JP3628746B2

JP3628746B2 - Elastic shaft coupling

Info

Publication number: JP3628746B2
Application number: JP04153095A
Authority: JP
Inventors: 眞白石
Original assignee: Kurashiki Kako Co Ltd
Current assignee: Kurashiki Kako Co Ltd
Priority date: 1995-03-01
Filing date: 1995-03-01
Publication date: 2005-03-16
Anticipated expiration: 2020-03-16
Also published as: JPH08232972A

Description

【０００１】
【産業上の利用分野】
本発明は、２本の軸を回転方向に弾性的な遊びをもって連結する弾性軸継手に関する。
【０００２】
【従来の技術】
実開昭５７−１３２８２１号公報には、上記２本の軸のうちの一方に結合する内筒の外周面と他方の軸に結合する外筒の内周面とを弾性体（ゴム）によって結合してなる弾性軸継手において、上記内筒及び外筒の断面形状を相似の長円形状にすることが記載されている。このような長円形状の内筒及び外筒の場合、両者が相対的な回転変位をすると、内筒の外周面と外筒の内周面との間の距離が変化するため、弾性体が部分的に圧縮されてストッパ効果が働く。よって、内筒と外筒との間の回転変位とこの両者間の伝達トルクとの関係をみた場合、この弾性軸継手では伝達トルクが急に高くなる非線形のバネ特性が得られる。
【０００３】
特開昭６０−２１５１２２号公報には、内筒及び外筒の断面形状を真円形状とした弾性軸継手において、内筒にストッパプレートを固定して該ストッパプレートの先端部を外筒の切欠き窓に差し込んだものが記載されている。このものでは両筒間の回転変位が大きくなったときにストッパプレートの先端部が上記切欠き窓において外筒に接触しストッパ機能を発揮する。また、特開平６−２７２７１８号公報には、上記ストッパプレートに代えて、内筒及び外筒を貫通するストッパピンを設けたものが記載されている。
【０００４】
【発明が解決しようとする課題】
しかし、上記長円形状の内筒と外筒とを用いた弾性軸継手の場合、そのバネ特性は確かに非線形になるものの、所期のストッパ効果を得るのが難しい。すなわち、内外の筒間の相対的な回転変位が小さい領域に遊びの効果をもたせるには、この両筒間にある程度の厚みを有する弾性体を設ける必要があるため、該弾性体が圧縮されてストッパ効果を発揮するまでの回転変位が大きくなる。従って、このような弾性軸継手を例えば自動車のステアリングシャフトに採用した場合、路面からの振動の伝達やシミーを防止すべく充分な遊び領域を確保すると、ストッパ効果の発揮が遅れて操舵性が低下する。
【０００５】
一方、上記ストッパプレートやストッパピンを用いた弾性軸継手の場合、かかるストッパ部材が外筒に当たったときに伝達トルクが急変するものの、内外の筒間に一定の回転変位があれば必ずストッパが働く。しかし、弾性軸継手にストッパ手段を設けるために、上記ストッパプレート等の組み込み、内外筒への面倒な機械加工を必要とし、また、部品点数も多くなる。
【０００６】
【課題を解決するための手段及びその作用】
本発明は、上記課題に対して、内筒や外筒自体をストッパに利用することによって、所期の遊び領域とストッパ効果とを簡単に得ることができるようにしたものである。以下、特許請求の範囲の各請求項に係る発明について具体的に説明する。
【０００７】
＜請求項１に係る発明＞
この発明は、互いに連結すべき２本の軸のうちの一方と一体になって回転する内側軸体の外周面と、他方の軸と一体になって回転する、全周にわたって連続した筒形になった外側軸体又は一対の半割状軸部材が合わされて筒形になった外側軸体の内周面とが弾性体によって連結されてなる弾性軸継手において、
上記外側軸体に、上記弾性体の端面の外側において該外側軸体の端部を内側に曲げることによって、上記内側軸体の外周面に向かって突出したストッパ部が形成され、
上記内側軸体の外周面は、上記ストッパ部が上記両軸体間に一定の回転変位を生じたときに当接するストッパ面を形成するように、当該軸体の回転中心からの距離が部分的に変化していることを特徴とする。
【０００８】
この発明においては、上記両軸体間の回転変位が一定未満であるときには、上記弾性体が弾性変形をすることによって緩衝効果を発揮し上記２本の軸間でのトルクないしは振動の伝達を抑制する。そして、上記両軸体間に一定の回転変位を生ずると、上記外側軸体に設けられたストッパ部が上記内側軸体の外周面のストッパ面に当接して上記２本の軸が直結状態になり、この両軸間で回転トルクが直接伝達される。
【０００９】
そうして、当該発明においては、ストッパ部が外側軸体の端部を曲げることによって形成されているから、従来のようなストッパプレートやストッパピンは不要であり、部品点数が少なくなるとともに、ストッパ部品の組み込みやそのための内外の軸体の機械加工が不要になる。また、上記ストッパ面が内側軸体の外周面によって形成されているから、このストッパ面を作るために内筒や外筒に特別な機械加工を施す必要はない。
【００１０】
ここに、上記ストッパ部は弾性体の端面の外側に設けられているが、内外の軸体間に軸方向に間隔をおいて２つの弾性体を設け、この両弾性体間に当該ストッパ部を形成することを本発明及び以下の各発明は含む。
【００１１】
＜請求項２に係る発明＞
この発明は、上記請求項１に記載されている弾性軸継手において、
上記ストッパ部及びストッパ面の各々が上記各軸体の回転中心に関して対称の位置関係になる２か所に設けられていることを特徴とする。
【００１２】
当該発明の場合、内外の軸体間に一定の回転変位を生じたときに点対称の関係に配置された２か所のストッパ部が同時に対応するストッパ面に当接するため、内外の軸体の軸心がずれることはなく、従って弾性体が局部的に異常変形することがない。
【００１３】
＜請求項３に係る発明＞
この発明は、互いに連結すべき２本の軸のうちの一方と一体になって回転する内側軸体の外周面と、他方の軸と一体になって回転する、全周にわたって連続した筒形になった外側軸体又は一対の半割状軸部材が合わされて筒形になった外側軸体の内周面とが弾性体によって連結されてなる弾性軸継手において、
上記内側軸体の外周面及び筒形になった外側軸体の内周面は、相似の非真円形に形成されていて、
上記外側軸体に、上記弾性体の端面の外側において該外側軸体の端部を内側に曲げることによって、上記内側軸体の外周面に向かって突出し該両軸体間に一定の回転変位を生じたときに該内側軸体の外周面に当接するストッパ部が形成されていることを特徴とする。
【００１４】
この発明においても、請求項１に係る発明の場合と同様に、弾性体によって弾性的な遊びを確保しながら、上記両軸体間に一定の回転変位を生じたときに上記ストッパ部を働かせて上記２本の軸を直結状態にすることができ、また、ストッパ部が外側軸体の端部を曲げることによって形成されているから、従来のようなストッパプレートやストッパピンは不要であり、部品点数が少なくなるとともに、ストッパ部品の組み込みやそのための内外の軸体の機械加工が不要になり、さらにストッパ面を別途形成する必要がない。
【００１５】
そうして、この発明では、内側軸体の外周面及び外側軸体の内周面が相似の非真円形に形成されているから、両軸体間に回転変位を生ずると両軸体の間隔が変化し、弾性体が部分的に圧縮されてストッパ効果が得られる。よって、この両軸体の形状的効果によって上記ストッパ部が働く前後で伝達トルクが急変することが防止される。また、上記両軸体間の弾性体もその肉厚が全周にわたって一定になり、弾性的な遊び領域を得る上で有利になる。
【００１６】
＜請求項４に係る発明＞
この発明は、上記請求項３に記載されている弾性軸継手において、
上記内側軸体の外周面及び筒形になった外側軸体の内周面の断面形状が、当該両軸体の回転中心に関して対称な非真円形に形成されていて、
上記ストッパ部が上記回転中心に関して対称の位置関係になる２か所に設けられていることを特徴とする。
【００１７】
この発明の場合は、内側軸体の外周面及び筒形になった外側軸体の内周面の断面形状が該両軸体の回転中心に関して対称な非真円形に形成されているから、同じく点対称に配置された２つのストッパ部に対応して２か所にストッパ面が形成されることになり、請求項２に係る発明と同様の作用が得られる。
【００１８】
＜請求項５に係る発明＞
この発明は、上記請求項４に記載されている弾性軸継手において、
上記内側軸体の外周面及び筒形になった外側軸体の内周面の断面形状が、相似の長円形状に形成されていて、
上記ストッパ部が、上記外側軸体の端部の長円形状における直線状に延びる部分を内側に曲げることによって形成され、該ストッパ部の先端が上記内側軸体の外周面の直線状に延びる部分と平行に形成されていることを特徴とする。
【００１９】
この発明の場合は、ストッパ部が上記外側軸体の端部を曲げることによって形成されているから、請求項１に係る発明と同様の作用が得られるが、さらに、内側軸体の外周面及び筒形になった外側軸体の内周面が長円形状であるから、同じく非真円形でも多角形状の場合とは違って、両軸体間に回転変位を生ずるときの弾性体の変形の仕方が部分的に大きく異なったものになることが少なく、弾性体の耐久性向上ないし内外の軸体からの剥離防止に有利になる。
【００２０】
ここに、上記外側軸体の長円形状における直線状に延びる部分にストッパ部を設け、該ストッパ部の先端を上記内側軸体の外周面の直線状に延びる部分と平行に形成しているのは、これによって、両軸体間に回転変位を生じたときに当該ストッパ部の先端が内側軸体の外周面に確実に当接するからである。
【００２１】
【発明の効果】
請求項１に係る発明によれば、外側軸体の端部を内側に曲げることによって内側軸体の外周面に向かって突出したストッパ部を形成し、該内側軸体の外周面を、ストッパ面が形成されるように、当該軸体の回転中心からの距離が部分的に変化してなる形状にしたから、ストッパ部品の組み込みやそのための内外の軸体の機械加工を要しないとともに、ストッパ面を作るために内外の軸体に特別な機械加工を施す必要はなく、両軸体間に一定の弾性的な遊びを得ながら、この両軸体間に一定の回転変位を生じたときには両軸体を直結状態にして確実にトルクを伝えることができる。
【００２２】
請求項２に係る発明によれば、上記請求項１に記載されている弾性軸継手において、上記ストッパ部及びストッパ面の各々を上記各軸体の回転中心に関して対称の位置関係になる２か所に設けているから、弾性体に局部的な異常変形を招くことなく、請求項１に係る発明の効果を得ることができる。
【００２３】
請求項３に係る発明によれば、内側軸体の外周面及び筒形になった外側軸体の内周面を相似の非真円形に形成し、外側軸体の端部を内側に曲げることによって、この両軸体間に一定の回転変位を生じたときに内側軸体の外周面に当接するストッパ部を形成したから、ストッパ部品の組み込みやそのための内外の軸体の機械加工を要しないとともに、ストッパ面を作るために内外の軸体に特別な機械加工を施す必要はなく、しかも、両軸体の形状に基づくストッパ効果を得ることができ、上記ストッパ部が働く前後で伝達トルクが急変することを防止することができる。
【００２４】
請求項４に係る発明によれば、上記請求項３に記載されている弾性軸継手において、上記内側軸体の外周面及び筒形になった外側軸体の内周面の断面形状を点対称な非真円形に形成し、同じく点対称の位置関係になるように２つのストッパ部を設けたから、請求項２に係る発明の効果と請求項３に係る発明の効果とを得ることができる。
【００２５】
請求項５に係る発明によれば、上記請求項４に記載されている弾性軸継手において、上記内側軸体の外周面及び筒形になった外側軸体の内周面の断面形状を相似の長円形とし、上記外側軸体の端の長円形状における直線状に延びる部分を内側に曲げることによってストッパ部を形成し、該ストッパ部の先端を上記内側軸体の外周面の直線状に延びる部分と平行に形成したから、弾性体の異常変形を防止してその耐久性を確保しながら、請求項３に係る発明及び請求項４に係る発明の効果を確実に得ることができる。
【００２６】
【実施例】
以下、本発明の実施例を図面に基づいて説明する。
【００２７】
＜実施例１＞
この実施例は本発明を自動車のステアリングシャフトの軸継手として用いたものである。図１において、１はステアリングホイール、２はインストルメントパネルのフレームに支持される上部シャフト、３は弾性軸継手４を有する中間シャフト、５は下部シャフト（パワーステアリング装置の入力軸）である。上部シャフト２、中間シャフト３及び下部シャフト５はユニバーサルジョイント６，６によって互いに連結されている。
【００２８】
上記弾性軸継手４の具体的な構造は図２及び図３に示されている。同図において、７は内側軸体、８は外側軸体であり、内側軸体７の外周面と外側軸体８の内周面とが全周にわたって弾性体（ゴム）９によって連結されている。内側軸体７及び外側軸体８は、断面形状が相似の長円形状になった筒体であって、互いに同心に配置されている。
【００２９】
そうして、上記外側軸体８の上端には、その長円形状の相対する直線状に延びる部分に内側へ曲げられたストッパ部１０，１０が設けられている。このストッパ部１０の先端は、上記内側軸体７の外周面の直線状に延びる部分と平行に直線状に延びており、該内側軸体７の外周面との間に一定のクリアランス１１が形成されている。この場合、上記内側軸体７の外周面の直線状に延びる部分が、内外の軸体７，８間に回転変位を生じたときに上記ストッパ部１０が当接するストッパ面１２になっている。
【００３０】
図４は、内外の軸体間の回転変位（捩れ角）と伝達トルクとの関係をみたものであり、同図において、破線で示す特性は内外の軸体の断面形状が真円形の弾性軸継手の場合（ストッパなし）、１点鎖線で示す特性は内外の軸体の断面形状が長円形の弾性軸継手の場合（ストッパなし）であり、実線で示す特性が上記実施例の弾性軸継手４のストッパ部１０とストッパ面１２との当接による効果を示している。
【００３１】
すなわち、上記実施例の弾性軸継手４の場合、内外の軸体７，８の断面形状が長円形状であるから、回転変位が小さい領域では１点鎖線で示すトルク伝達特性となり、この内外の軸体７，８の形状に起因するストッパ効果が得られ、上記ストッパ部１０とストッパ面１２とが当接する回転変位量になると、この当該当接によって内外の軸体７，８が回転方向において直結状態になり、実線で示すように伝達トルクが立ち上がる。
【００３２】
従って、上記回転変位が小さい領域ではトルクの伝達が少なく、弾性体９がトルクの伝達を緩和する緩衝作用を発揮し、路面の凹凸による車輪の振動がステアリングホイールに伝わることが防止されるとともに、シミーも防止される。そして、上記回転変位が大きくなると、上記ストッパ部１０とストッパ面１２との当接によってステアリングホイール１の回転が直接的にパワーステアリング装置の方に伝わるようになるが、その過渡期においては、上記内外の軸体７，８の形状に起因するストッパ効果が働くから、伝達トルクの急変が避けられ、運転者は違和感を覚えることがなくなり、操舵性の向上に有利になる。
【００３３】
なお、上記内外の軸体７，８の各々の端部にフランジを設け、これを連結すべき２本の軸の各々に結合することができることはもちろんである。
【００３４】
＜実施例２＞
この実施例については図５及び図６に示されている。実施例１の外側軸体８は全周にわたって連続した筒形になったものであるが、この実施例２では、弾性軸継手１４の外側軸体１８は、一対の半割状軸部材１８ａ，１８ａが合わされて断面形状が長円形状の筒形になるものである。内側軸体７は実施例１と同じものである。
【００３５】
すなわち、内側軸体７の外周面と外側軸体１８の各軸部材１８ａ，１８ａの内周面とは弾性体（ゴム）９ａ，９ａによって連結されている。外側軸体１８は、図５に示すように、これを結合すべき軸に組付ける前の自由な状態では２つの軸部材１８ａ，１８が離れている。そして、図６に示すように、外側軸体１８を結合すべき断面長円形状の軸２０に弾性軸継手１４を圧入することによって、上記両軸部材１８ａ，１８ａを弾性体９ａ，９ａの弾発力に抗して内側に寄せ合わせ断面長円形状の筒形になった外側軸体１８を形成することになる。また、各軸部材１８ａには実施例１と同様のストッパ部１０が形成されている。
【００３６】
従って、本例の場合は、弾性軸継手１４を軸２０に圧入することによって、弾性体９ａ，９ａに適度の予圧縮を与えて所望のバネ特性を得ることができる。また、外側軸体１８の各軸部材１８ａについては、パイプ材を半割にして成形することもできるが、ストッパ部１０を含めて該軸部材１８ａを圧延鋼板からプレス成形することができ、その場合はパイプ材から成形する場合に比べてコストの低減に有利になる。
【００３７】
なお、本発明の弾性軸継手は上記ステアリングシャフト以外の軸継手として利用することができる。
【図面の簡単な説明】
【図１】自動車のステアリングを示す側面図
【図２】実施例１の弾性軸継手の横断面図（図３のＡ−Ａ断面図）
【図３】同例の弾性軸継手の縦断面図
【図４】弾性軸継手のバネ特性を示すグラフ図
【図５】実施例２の弾性軸継手の自由状態の横断面図
【図６】同例の弾性軸継手を軸に圧入した状態の横断面図
【符号の説明】
１ステアリングホイール
２上部シャフト
３中間シャフト
４，１４弾性軸継手
５下部シャフト
７内側軸体
８，１８外側軸体
９，９ａ弾性体
１０ストッパ部
１１クリアランス
１２ストッパ面
１８ａ半割状軸部材[0001]
[Industrial application fields]
The present invention relates to an elastic shaft coupling that connects two shafts with elastic play in the rotational direction.
[0002]
[Prior art]
In Japanese Utility Model Laid-Open No. 57-132821, the outer peripheral surface of the inner cylinder coupled to one of the two shafts and the inner peripheral surface of the outer cylinder coupled to the other shaft are coupled by an elastic body (rubber). In the elastic shaft joint formed as described above, it is described that the cross-sectional shapes of the inner cylinder and the outer cylinder are similar oval shapes. In the case of such an oval inner cylinder and outer cylinder, if the relative rotational displacement of both, the distance between the outer peripheral surface of the inner cylinder and the inner peripheral surface of the outer cylinder changes, so the elastic body Partially compressed, the stopper effect works. Therefore, when the relationship between the rotational displacement between the inner cylinder and the outer cylinder and the transmission torque between the two is viewed, this elastic shaft coupling can obtain a non-linear spring characteristic in which the transmission torque increases rapidly.
[0003]
In Japanese Patent Laid-Open No. 60-215122, in an elastic shaft coupling in which the cross-sectional shape of the inner cylinder and the outer cylinder is a perfect circle, a stopper plate is fixed to the inner cylinder, and the tip of the stopper plate is cut off from the outer cylinder. What is inserted into the notch window is described. In this case, when the rotational displacement between the two cylinders becomes large, the tip of the stopper plate comes into contact with the outer cylinder at the notch window and exhibits a stopper function. Japanese Patent Application Laid-Open No. 6-272718 describes that a stopper pin penetrating the inner cylinder and the outer cylinder is provided in place of the stopper plate.
[0004]
[Problems to be solved by the invention]
However, in the case of the elastic shaft coupling using the above-mentioned elliptical inner cylinder and outer cylinder, the spring characteristics are certainly non-linear, but it is difficult to obtain the desired stopper effect. That is, in order to provide an effect of play in a region where the relative rotational displacement between the inner and outer cylinders is small, it is necessary to provide an elastic body having a certain thickness between the two cylinders. The rotational displacement until the stopper effect is exhibited increases. Therefore, when such an elastic shaft coupling is used for a steering shaft of an automobile, for example, if a sufficient play area is secured to prevent transmission of vibration from the road surface and shimmy, the stopper effect is delayed and the steering performance is lowered. To do.
[0005]
On the other hand, in the case of the elastic shaft coupling using the stopper plate and the stopper pin, the transmission torque changes suddenly when the stopper member hits the outer cylinder. However, if there is a constant rotational displacement between the inner and outer cylinders, the stopper must be installed. work. However, in order to provide the stopper means on the elastic shaft coupling, it is necessary to incorporate the stopper plate or the like and troublesome machining into the inner and outer cylinders, and the number of parts increases.
[0006]
[Means for Solving the Problem and Action]
In the present invention, an intended play area and a stopper effect can be easily obtained by using an inner cylinder or an outer cylinder itself as a stopper. Hereinafter, the invention according to each claim of the claims will be specifically described.
[0007]
<Invention according to Claim 1>
The present invention has an outer peripheral surface of an inner shaft that rotates integrally with one of two shafts to be connected to each other, and a cylindrical shape that rotates integrally with the other shaft and is continuous over the entire circumference. In the elastic shaft joint formed by connecting the outer shaft body or the pair of halved shaft members and the inner peripheral surface of the cylindrical outer shaft body connected by an elastic body,
To the outer shaft member, by bending the end portion of the outer shaft body inside the outer end face of the elastic member, a stopper portion protruding toward the outer peripheral surface of the inner shaft is formed,
The outer peripheral surface of the inner shaft body is partially separated from the rotation center of the shaft body so as to form a stopper surface that comes into contact when the stopper portion is caused to rotate at a certain rotational displacement between the shaft bodies. It is characterized by having changed.
[0008]
In the present invention, when the rotational displacement between the two shafts is less than a certain value, the elastic body is elastically deformed to exhibit a buffering effect and suppress transmission of torque or vibration between the two shafts. To do. When a certain rotational displacement is generated between the two shaft bodies, the stopper portion provided on the outer shaft body comes into contact with the stopper surface of the outer peripheral surface of the inner shaft body so that the two shafts are directly connected. Thus, rotational torque is directly transmitted between the two shafts.
[0009]
Thus, in the present invention, since the stopper portion is formed by bending the end portion of the outer shaft body, the conventional stopper plate and stopper pin are unnecessary, the number of parts is reduced, and the stopper is reduced. There is no need to incorporate parts or machine the inner and outer shafts for that purpose. Further, since the stopper surface is formed by the outer peripheral surface of the inner shaft body, it is not necessary to perform special machining on the inner cylinder or the outer cylinder in order to make the stopper surface.
[0010]
Here, the stopper portion is provided outside the end face of the elastic body. However, two elastic bodies are provided in the axial direction between the inner and outer shaft bodies, and the stopper portion is provided between the elastic bodies. The present invention and the following inventions include the formation.
[0011]
<Invention according to Claim 2>
The present invention provides the elastic shaft coupling according to claim 1,
Each of the stopper portion and the stopper surface is provided at two locations having a symmetrical positional relationship with respect to the rotation center of each shaft body.
[0012]
In the case of the present invention, when a certain rotational displacement occurs between the inner and outer shaft bodies, the two stopper portions arranged in a point-symmetrical relationship simultaneously abut against the corresponding stopper surfaces. The axis does not shift, and therefore the elastic body does not deform abnormally locally.
[0013]
<Invention according to claim 3 >
The present invention has an outer peripheral surface of an inner shaft that rotates integrally with one of two shafts to be connected to each other, and a cylindrical shape that rotates integrally with the other shaft and is continuous over the entire circumference. In the elastic shaft joint formed by connecting the outer shaft body or the pair of halved shaft members and the inner peripheral surface of the cylindrical outer shaft body connected by an elastic body,
The outer peripheral surface of the inner shaft body and the inner peripheral surface of the cylindrical outer shaft body are formed in a similar non-true circle,
To the outer shaft member, by bending the end portion of the outer shaft body inside the outer end face of the elastic body, a constant rotational displacement between projecting the both shaft body toward the outer peripheral surface of the inner shaft the stopper portion abutting the outer peripheral surface of the inner shaft when produced is formed, characterized in.
[0014]
In this invention as well, in the same way as in the case of the invention according to claim 1, while the elastic play is secured by the elastic body, the stopper portion is operated when a certain rotational displacement occurs between the shaft bodies. Since the two shafts can be directly connected, and the stopper portion is formed by bending the end portion of the outer shaft body, the conventional stopper plate and stopper pin are unnecessary, and the parts As the number of points is reduced, it is not necessary to incorporate stopper parts and machine the inner and outer shafts for that purpose, and it is not necessary to separately form a stopper surface.
[0015]
Thus, in the present invention, the outer peripheral surface of the inner shaft body and the inner peripheral surface of the outer shaft body are formed in a similar non-circular shape. Changes, and the elastic body is partially compressed to obtain a stopper effect. Therefore, it is possible to prevent the transmission torque from changing suddenly before and after the stopper portion works due to the shape effect of both shaft bodies. The thickness of the elastic body between the two shaft bodies is constant over the entire circumference, which is advantageous for obtaining an elastic play area.
[0016]
<Invention according to claim 4 >
The present invention provides the elastic shaft coupling according to claim 3 ,
The cross-sectional shape of the outer peripheral surface of the inner shaft body and the inner peripheral surface of the cylindrical outer shaft body is formed in a non-true circle symmetric with respect to the rotation center of the two shaft bodies,
The stopper portion is provided at two places having a symmetrical positional relationship with respect to the rotation center.
[0017]
In the case of this invention, since the cross-sectional shape of the outer peripheral surface of the inner shaft body and the inner peripheral surface of the cylindrical outer shaft body is formed in a non-true circle symmetric with respect to the rotation center of both shaft bodies, The stopper surfaces are formed at two locations corresponding to the two stopper portions arranged symmetrically with respect to the point, and the same operation as the invention according to claim 2 is obtained.
[0018]
<Invention according to claim 5 >
The present invention provides the elastic shaft coupling according to claim 4 ,
The cross-sectional shape of the outer peripheral surface of the inner shaft body and the inner peripheral surface of the cylindrical outer shaft body is formed in a similar oval shape,
The stopper portion is formed by bending inwardly a linearly extending portion of the end portion of the outer shaft body, and the tip portion of the stopper portion extends linearly on the outer peripheral surface of the inner shaft body It is characterized by being formed in parallel.
[0019]
In the case of this invention, since the stopper portion is formed by bending the end portion of the outer shaft body, the same effect as that of the invention according to claim 1 can be obtained. Since the inner peripheral surface of the cylindrical outer shaft has an oval shape, the deformation of the elastic body when rotational displacement occurs between the two shafts is different from the case of a polygonal shape even if it is non-circular. It is unlikely that the method is greatly different in part, which is advantageous for improving the durability of the elastic body and preventing peeling from the inner and outer shaft bodies.
[0020]
Here, a stopper portion is provided in the linearly extending portion of the outer shaft body, and the tip of the stopper portion is formed in parallel with the linearly extending portion of the outer peripheral surface of the inner shaft body. This is because the tip of the stopper portion reliably comes into contact with the outer peripheral surface of the inner shaft when a rotational displacement occurs between the two shafts.
[0021]
【The invention's effect】
According to the invention of claim 1, the stopper portion is formed projecting toward the outer peripheral surface of the inner shaft by bending the end of the outer shaft body inward, the outer peripheral surface of the inner shaft, the stopper surface Since the distance from the center of rotation of the shaft body is partially changed so that is formed, it is not necessary to incorporate stopper parts or machine the inner and outer shaft bodies for that purpose, It is not necessary to apply special machining to the inner and outer shafts to make a shaft. When a certain rotational displacement occurs between the two shafts while obtaining a certain elastic play between the two shafts, both shafts Torque can be transmitted reliably with the body directly connected.
[0022]
According to the invention according to claim 2, in the elastic shaft joint according to claim 1, the stopper portion and the stopper surface each have two symmetrical positions with respect to the rotation center of each shaft body. Therefore, the effect of the invention according to claim 1 can be obtained without causing local abnormal deformation in the elastic body.
[0023]
According to the invention of claim 3 , the outer peripheral surface of the inner shaft body and the inner peripheral surface of the cylindrical outer shaft body are formed in a similar non-circular shape, and the end portion of the outer shaft body is bent inward. Thus, when a constant rotational displacement is generated between the two shaft bodies, the stopper portion that contacts the outer peripheral surface of the inner shaft body is formed , so that it is not necessary to incorporate stopper parts or machine the inner and outer shaft bodies for that purpose. At the same time, there is no need to perform special machining on the inner and outer shaft bodies in order to make the stopper surface, and a stopper effect based on the shape of both shaft bodies can be obtained, and the transmission torque is increased before and after the stopper portions work. Sudden changes can be prevented.
[0024]
According to the invention according to claim 4 , in the elastic shaft joint according to claim 3 , the cross-sectional shapes of the outer peripheral surface of the inner shaft body and the inner peripheral surface of the cylindrical outer shaft body are point-symmetric. Since the two stopper portions are provided so as to have a non-true circular shape and also have a point-symmetrical positional relationship, the effect of the invention according to claim 2 and the effect of the invention according to claim 3 can be obtained.
[0025]
According to the invention of claim 5 , in the elastic shaft joint described in claim 4 , the cross-sectional shape of the outer peripheral surface of the inner shaft body and the inner peripheral surface of the cylindrical outer shaft body is similar. A stopper portion is formed by bending an inwardly extending portion of the oval shape of the end of the outer shaft body inwardly, and the tip of the stopper portion extends linearly on the outer peripheral surface of the inner shaft body. Since it is formed in parallel with the portion, the effect of the invention according to claim 3 and the invention according to claim 4 can be reliably obtained while preventing abnormal deformation of the elastic body and ensuring its durability.
[0026]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
[0027]
<Example 1>
In this embodiment, the present invention is used as a shaft coupling of a steering shaft of an automobile. In FIG. 1, 1 is a steering wheel, 2 is an upper shaft supported by the frame of the instrument panel, 3 is an intermediate shaft having an elastic shaft joint 4, and 5 is a lower shaft (input shaft of a power steering device). The upper shaft 2, the intermediate shaft 3 and the lower shaft 5 are connected to each other by universal joints 6 and 6.
[0028]
The specific structure of the elastic shaft coupling 4 is shown in FIGS. In the figure, reference numeral 7 denotes an inner shaft body, and 8 denotes an outer shaft body. The outer peripheral surface of the inner shaft body 7 and the inner peripheral surface of the outer shaft body 8 are connected by an elastic body (rubber) 9 over the entire circumference. . The inner shaft body 7 and the outer shaft body 8 are cylindrical bodies whose cross-sectional shapes are similar to each other, and are arranged concentrically with each other.
[0029]
Thus, at the upper end of the outer shaft body 8, stopper portions 10, 10 bent inward are provided at the portions of the oval shape extending in the opposite straight lines. The tip of the stopper portion 10 extends linearly in parallel with the linearly extending portion of the outer peripheral surface of the inner shaft body 7, and a constant clearance 11 is formed between the outer peripheral surface of the inner shaft body 7. Has been. In this case, a linearly extending portion of the outer peripheral surface of the inner shaft body 7 is a stopper surface 12 with which the stopper portion 10 abuts when rotational displacement occurs between the inner and outer shaft bodies 7 and 8.
[0030]
FIG. 4 shows the relationship between the rotational displacement (torsion angle) between the inner and outer shaft bodies and the transmission torque. In the figure, the characteristic indicated by the broken line indicates an elastic shaft whose inner and outer shaft bodies have a true circular cross section. In the case of a joint (without stopper), the characteristics indicated by the one-dot chain line are for an elastic shaft joint whose inner and outer shaft bodies are oval in cross section (no stopper), and the characteristics indicated by the solid line are the elastic shaft joints of the above embodiment. The effect by contact | abutting of the stopper part 10 and the stopper surface 12 of 4 is shown.
[0031]
That is, in the case of the elastic shaft joint 4 of the above embodiment, the cross-sectional shape of the inner and outer shaft bodies 7 and 8 is an oval shape. When the stopper effect resulting from the shape of the shaft bodies 7 and 8 is obtained and the rotational displacement amount at which the stopper portion 10 and the stopper surface 12 are in contact with each other, the contact causes the inner and outer shaft bodies 7 and 8 to move in the rotational direction. It becomes a direct connection state, and the transmission torque rises as shown by the solid line.
[0032]
Accordingly, in the region where the rotational displacement is small, the transmission of torque is small, and the elastic body 9 exerts a buffering action that relaxes the transmission of torque, preventing the vibration of the wheel due to road surface unevenness from being transmitted to the steering wheel, Shimmy is also prevented. When the rotational displacement increases, the rotation of the steering wheel 1 is directly transmitted to the power steering device due to the contact between the stopper portion 10 and the stopper surface 12, but in the transition period, Since the stopper effect due to the shapes of the inner and outer shaft bodies 7 and 8 works, a sudden change in transmission torque is avoided, and the driver does not feel uncomfortable, which is advantageous in improving the steering performance.
[0033]
Na us, a flange provided at an end of each of said inner and outer shafts 7 and 8, it is a matter of course that capable of binding to each of the two shafts to be connected to this.
[0034]
<Example 2>
This embodiment is shown in FIGS. 5 and 6. FIG. The outer shaft body 8 of the first embodiment has a cylindrical shape that is continuous over the entire circumference. However, in this second embodiment, the outer shaft body 18 of the elastic shaft coupling 14 has a pair of halved shaft members 18a, 18a is combined to form a cylindrical shape with an oval cross-sectional shape. The inner shaft body 7 is the same as that in the first embodiment.
[0035]
That is, the outer peripheral surface of the inner shaft body 7 and the inner peripheral surfaces of the shaft members 18a and 18a of the outer shaft body 18 are connected by elastic bodies (rubbers) 9a and 9a. As shown in FIG. 5, the outer shaft body 18 is separated from the two shaft members 18a and 18 in a free state before being assembled to the shaft to be coupled. Then, as shown in FIG. 6, the elastic shaft joint 14 is press-fitted into a shaft 20 having an oval cross section to which the outer shaft body 18 is to be coupled, whereby the shaft members 18a and 18a are elastically coupled to the elastic bodies 9a and 9a. The outer shaft 18 having a cylindrical shape with an oval cross section is formed on the inner side against the generated force. Each shaft member 18a is formed with a stopper portion 10 similar to that in the first embodiment.
[0036]
Therefore, in the case of this example, by pressing the elastic shaft coupling 14 into the shaft 20, it is possible to obtain a desired spring characteristic by applying appropriate pre-compression to the elastic bodies 9a, 9a. Further, each shaft member 18a of the outer shaft body 18 can be formed by halving the pipe material, but the shaft member 18a including the stopper portion 10 can be press-formed from a rolled steel plate, In this case, it is advantageous for cost reduction as compared with the case of molding from pipe material.
[0037]
The elastic shaft coupling of the present invention can be used as a shaft coupling other than the steering shaft.
[Brief description of the drawings]
FIG. 1 is a side view showing a steering of an automobile. FIG. 2 is a cross-sectional view of an elastic shaft joint according to a first embodiment (A-A cross-sectional view in FIG. 3).
3 is a longitudinal sectional view of the elastic shaft coupling of the same example. FIG. 4 is a graph showing the spring characteristics of the elastic shaft coupling. FIG. 5 is a transverse sectional view of the elastic shaft coupling of Example 2 in a free state. Cross-sectional view of the elastic shaft joint of the same example pressed into the shaft 【Explanation of symbols】
DESCRIPTION OF SYMBOLS 1 Steering wheel 2 Upper shaft 3 Intermediate shaft 4, 14 Elastic shaft coupling 5 Lower shaft 7 Inner shaft body 8, 18 Outer shaft body 9, 9a Elastic body 10 Stopper part 11 Clearance 12 Stopper surface 18a Half-shaped shaft member

Claims

The outer peripheral surface of the inner shaft that rotates integrally with one of the two shafts to be connected to each other, and the outer shaft that is continuous with the entire circumference and rotates integrally with the other shaft. In the elastic shaft coupling in which the body or the pair of halved shaft members are joined to each other and the inner peripheral surface of the outer shaft body formed into a cylindrical shape are connected by an elastic body,
To the outer shaft member, by bending the end portion of the outer shaft body inside the outer end face of the elastic member, a stopper portion protruding toward the outer peripheral surface of the inner shaft is formed,
The outer peripheral surface of the inner shaft body is partially separated from the rotation center of the shaft body so as to form a stopper surface that comes into contact when the stopper portion is caused to rotate at a certain rotational displacement between the shaft bodies. An elastic shaft coupling characterized by being changed to

In the elastic shaft coupling according to claim 1,
An elastic shaft coupling, wherein each of the stopper portion and the stopper surface is provided at two locations having a symmetrical positional relationship with respect to the rotation center of each shaft body.

The outer peripheral surface of the inner shaft that rotates integrally with one of the two shafts to be connected to each other, and the outer shaft that is continuous with the entire circumference and rotates integrally with the other shaft. In the elastic shaft coupling in which the body or the pair of halved shaft members are joined to each other and the inner peripheral surface of the outer shaft body formed into a cylindrical shape are connected by an elastic body,
The outer peripheral surface of the inner shaft body and the inner peripheral surface of the cylindrical outer shaft body are formed in a similar non-true circle,
To the outer shaft member, by bending the end portion of the outer shaft body inside the outer end face of the elastic body, a constant rotational displacement between projecting the both shaft body toward the outer peripheral surface of the inner shaft resulting elastic coupling, characterized in that the stopper portion abutting the outer peripheral surface of the inner shaft is formed when the.

In the elastic shaft coupling according to claim 3 ,
The cross-sectional shape of the outer peripheral surface of the inner shaft body and the inner peripheral surface of the cylindrical outer shaft body is formed in a non-true circle symmetric with respect to the rotation center of the two shaft bodies,
The elastic shaft coupling is characterized in that the stopper portion is provided at two places having a symmetrical positional relationship with respect to the rotation center.

In the elastic shaft coupling according to claim 4 ,
The cross-sectional shape of the outer peripheral surface of the inner shaft body and the inner peripheral surface of the cylindrical outer shaft body is formed in a similar oval shape,
The stopper portion is formed by bending inwardly a linearly extending portion of the end portion of the outer shaft body, and the tip portion of the stopper portion extends linearly on the outer peripheral surface of the inner shaft body It is formed in parallel with the elastic shaft coupling.