JP6284712B2

JP6284712B2 - Constant velocity universal joint

Info

Publication number: JP6284712B2
Application number: JP2013085649A
Authority: JP
Inventors: 輝明藤尾; 正純小林; 賢二山田
Original assignee: NTN Corp
Current assignee: NTN Corp
Priority date: 2013-04-16
Filing date: 2013-04-16
Publication date: 2018-02-28
Anticipated expiration: 2033-04-16
Also published as: JP2014206262A

Description

本発明は、自動車、航空機、船舶や各種産業機械の動力伝達系において使用され、例えば４ＷＤ車やＦＲ車などで使用されるドライブシャフトやプロペラシャフト等に組み込まれて駆動側と従動側の二軸間で角度変位を許容する等速自在継手に関する。 The present invention is used in power transmission systems of automobiles, airplanes, ships, and various industrial machines, and is incorporated into a drive shaft, a propeller shaft, etc. used in, for example, a 4WD vehicle, an FR vehicle, etc. It is related with the constant velocity universal joint which accept | permits an angular displacement between.

例えば、自動車のエンジンから駆動車輪に動力を伝達するドライブシャフトは、エンジンと車輪との相対的位置関係の変化による角度変位と軸方向変位に対応する必要があるため、一般的に、エンジン側（インボード側）に摺動式等速自在継手を、駆動車輪側（アウトボード側）に固定式等速自在継手をそれぞれ装備し、両者の等速自在継手をシャフトで連結した構造を具備する。このドライブシャフトを構成するシャフトの両端に設けられた等速自在継手は、内側継手部材の軸孔にシャフトの先端部を挿入してスプライン嵌合させたトルク伝達可能な構造を具備する。 For example, a drive shaft that transmits power from an automobile engine to a drive wheel needs to cope with an angular displacement and an axial displacement caused by a change in the relative positional relationship between the engine and the wheel. A sliding type constant velocity universal joint is provided on the inboard side, and a fixed type constant velocity universal joint is provided on the drive wheel side (outboard side), and both constant velocity universal joints are connected by a shaft. The constant velocity universal joint provided at both ends of the shaft constituting the drive shaft has a structure capable of transmitting torque by inserting the tip of the shaft into the shaft hole of the inner joint member and performing spline fitting.

この種の等速自在継手では、ブーツ交換などの整備工数の簡略化を図るため、内部部品である内側継手部材とシャフトとを分解可能に結合させたシャフト抜け止め構造が採用されている（例えば、特許文献１参照）。 This type of constant velocity universal joint employs a shaft retaining structure in which an inner joint member, which is an internal component, and a shaft are releasably coupled in order to simplify maintenance work such as boot replacement (for example, , See Patent Document 1).

本出願人が先に提案した特許文献１のシャフト抜け止め構造は、シャフトの先端部に環状凹溝を形成すると共に内側継手部材の軸孔端部に当接部を形成している。この内側継手部材の軸孔にシャフトの先端部を挿入するに際して、シャフトの環状凹溝に弾性的に縮径可能な止め輪を装着し、シャフトの挿入後、縮径状態にある止め輪が内側継手部材の当接部に達した時点で、その止め輪を弾性復元力でもって拡径させることにより内側継手部材の当接部に係止させるようにしている。 In the shaft retaining structure of Patent Document 1 previously proposed by the present applicant, an annular concave groove is formed at the tip of the shaft and an abutting portion is formed at the end of the shaft hole of the inner joint member. When inserting the tip of the shaft into the shaft hole of the inner joint member, a retaining ring that can be elastically reduced in diameter is attached to the annular groove in the shaft, and after the shaft is inserted, the retaining ring in the reduced diameter state is placed on the inner side. When the contact portion of the joint member is reached, the retaining ring is expanded by an elastic restoring force so as to be engaged with the contact portion of the inner joint member.

このシャフト抜け止め構造では、環状凹溝のシャフト先端側に、軸方向（シャフトの引き抜き方向）と直交する面に対して角度αで傾斜する係止面が形成されている。また、内側継手部材の当接部には、軸方向（シャフトの引き抜き方向）と直交する面に対して角度βで傾斜する係止面が形成されている。この環状凹溝の係止面の傾斜角度αと当接部の係止面の傾斜角度βとの相対角度β−αを規定することにより、内側継手部材とシャフトとが分解可能な分解構造、あるいは内側継手部材とシャフトとが分解不可能な非分解構造を選択可能としている。 In this shaft retaining structure, a locking surface that is inclined at an angle α with respect to a surface perpendicular to the axial direction (shaft drawing direction) is formed on the tip end side of the annular groove. Further, the contact portion of the inner joint member is formed with a locking surface that is inclined at an angle β with respect to a surface orthogonal to the axial direction (shaft drawing direction). An exploded structure in which the inner joint member and the shaft can be disassembled by defining a relative angle β-α between the inclination angle α of the locking surface of the annular groove and the inclination angle β of the locking surface of the contact portion, Alternatively, it is possible to select a non-disassembly structure in which the inner joint member and the shaft cannot be disassembled.

つまり、環状凹溝の係止面の傾斜角度αと当接部の係止面の傾斜角度βとの相対角度β−αを大きく設定することにより（β−α＞１９°）、シャフトの引き抜き力により止め輪が内側継手部材の当接部の係止面に沿って縮径し、その当接部から離脱するような分解構造としている。一方、環状凹溝の係止面の傾斜角度αと当接部の係止面の傾斜角度βとの相対角度β−αを小さく設定することにより（０°≦β−α≦１９°）、シャフトの引き抜き力が作用しても止め輪が内側継手部材の当接部の係止面に沿って縮径せず、その当接部から離脱しないような非分解構造としている。 That is, by setting the relative angle β-α between the inclination angle α of the engaging surface of the annular groove and the inclination angle β of the engaging surface of the contact portion (β-α> 19 °), the shaft is pulled out. The disassembly structure is such that the retaining ring is reduced in diameter along the locking surface of the abutting portion of the inner joint member by force and is detached from the abutting portion. On the other hand, by setting a relative angle β-α between the inclination angle α of the locking surface of the annular groove and the inclination angle β of the locking surface of the contact portion (0 ° ≦ β−α ≦ 19 °), Even if a pulling force of the shaft is applied, the retaining ring does not shrink along the locking surface of the abutting portion of the inner joint member and does not separate from the abutting portion.

特許第４９６４４１７号公報Japanese Patent No. 4964417

ところで、特許文献１で開示されたシャフト抜け止め構造では、シャフトの環状凹溝のシャフト先端側に、軸方向（シャフトの引き抜き方向）と直交する面に対して角度αで傾斜する係止面を設けることにより、その環状凹溝の係止面の傾斜角度αと当接部の係止面の傾斜角度βとの相対角度β−αが１９°よりも大きいか小さいかでもって、内側継手部材とシャフトとの分解構造あるいは非分解構造を選択可能としている。 By the way, in the shaft retaining structure disclosed in Patent Document 1, a locking surface that is inclined at an angle α with respect to a surface orthogonal to the axial direction (shaft drawing direction) is provided on the shaft front end side of the annular groove of the shaft. By providing the inner joint member, the relative angle β-α between the inclination angle α of the engaging surface of the annular groove and the inclination angle β of the engaging surface of the abutting portion is larger or smaller than 19 °. The disassembly structure or non-disassembly structure of the shaft and the shaft can be selected.

このシャフト抜け止め構造では、内側継手部材の軸孔にシャフトの先端部を挿入するに際して、止め輪がシャフトの環状凹溝に嵌まり込んで確実に縮径することができるように環状凹溝の軸方向長さを確保する必要があり、また、係止面がシャフト先端側に向けて拡開するように傾斜している。このことから、シャフトの環状凹溝の係止面と内側継手部材の当接部の係止面との間で止め輪の軸方向ガタ量が大きくなるという問題があった。この内側継手部材とシャフトとの組み付け後に止め輪の軸方向ガタ量が大きいと、車両における異音、振動が発生する原因となる。 In this shaft retaining structure, when the tip of the shaft is inserted into the shaft hole of the inner joint member, the retaining groove is fitted into the annular groove of the shaft so that the diameter can be reliably reduced. It is necessary to ensure the length in the axial direction, and the locking surface is inclined so as to expand toward the tip end side of the shaft. For this reason, there has been a problem that the amount of backlash in the axial direction of the retaining ring increases between the engaging surface of the annular groove of the shaft and the engaging surface of the contact portion of the inner joint member. If the amount of play in the axial direction of the retaining ring is large after the inner joint member and the shaft are assembled, it may cause abnormal noise and vibration in the vehicle.

そこで、本発明は前述の改善点に鑑みて提案されたもので、その目的とするところは、簡便な構造でもって、シャフトの環状凹溝の係止面と内側継手部材の当接部の係止面との間で止め輪の軸方向ガタを抑制して異音および振動の発生を未然に防止し得る等速自在継手を提供することにある。 Accordingly, the present invention has been proposed in view of the above-described improvements, and the object of the present invention is to have a simple structure and to engage the engagement surface of the annular groove of the shaft with the contact portion of the inner joint member. An object of the present invention is to provide a constant velocity universal joint that can prevent the occurrence of abnormal noise and vibration by suppressing axial play of the retaining ring between the retaining surface and the retaining surface.

前述の目的を達成するための技術的手段として、本発明は、外側継手部材と、その外側継手部材との間でトルク伝達部材を介して角度変位を許容しながらトルクを伝達する内側継手部材とを備え、その内側継手部材の軸孔にシャフトの先端部を挿入してトルク伝達可能に嵌合させ、シャフトの環状凹溝に弾性的に縮径可能に装着された止め輪を、内側継手部材の軸孔端部に形成された当接部に当接させることにより、内側継手部材に対してシャフトを抜け止めする等速自在継手であって、環状凹溝のシャフト先端側は、シャフトの外周面から径方向内側へ延びるように形成され軸方向と直交する面に対して傾斜する係止面と、係止面に隣接して径方向内側に延びるように形成され軸方向と直交する面に対して平行な壁面とで構成され、シャフトへの引き抜き力の作用時、止め輪は、シャフトの環状凹溝の係止面と、内側継手部材の当接部の係止面および円筒面とで挟み込まれ、内側継手部材の当接部の係止面の傾斜角度βと、シャフトの環状凹溝の係止面の傾斜角度αとの相対角度β−αを８°以下としたことを特徴とする。 As technical means for achieving the aforementioned object, the present invention includes an outer joint member, an inner joint member that transmits torque while allowing angular displacement between the outer joint member via the torque transmission member, and The inner end of the inner joint member is inserted into the shaft hole of the shaft and fitted so that torque can be transmitted. The constant velocity universal joint prevents the shaft from coming off from the inner joint member by abutting against the abutting portion formed at the end portion of the shaft hole, and the front end side of the annular groove is the outer periphery of the shaft. A locking surface formed to extend radially inward from the surface and inclined with respect to a surface orthogonal to the axial direction, and a surface formed to extend radially inward adjacent to the locking surface and orthogonal to the axial direction It is composed of a parallel walls for, Schaff When the pulling force acts on the retaining ring, the retaining ring is sandwiched between the engaging surface of the annular groove of the shaft and the engaging surface and the cylindrical surface of the abutting portion of the inner joint member. The relative angle β-α between the inclination angle β of the engaging surface and the inclination angle α of the engaging surface of the annular groove of the shaft is set to 8 ° or less .

本発明では、環状凹溝のシャフト先端側でシャフトの外周面から径方向内側へ延びるように形成され、軸方向と直交する面に対して傾斜する係止面に隣接して、軸方向と直交する面に対して平行な壁面を径方向内側へ延びるように形成したことにより、軸方向と直交する面に対して傾斜する係止面のみが形成された従来の等速自在継手（特許文献１参照）の場合よりも、シャフトの環状凹溝の係止面と内側継手部材の当接部の係止面との間で止め輪の軸方向ガタ量を小さくすることができる。 In the present invention, it is formed so as to extend radially inward from the outer peripheral surface of the shaft on the shaft front end side of the annular groove, adjacent to the locking surface inclined with respect to the surface orthogonal to the axial direction, and orthogonal to the axial direction. A conventional constant velocity universal joint in which only a locking surface that is inclined with respect to a surface orthogonal to the axial direction is formed by forming a wall surface parallel to the surface to extend radially inward (Patent Document 1) The axial backlash amount of the retaining ring can be reduced between the engaging surface of the annular groove of the shaft and the engaging surface of the contact portion of the inner joint member.

つまり、内側継手部材の軸孔にシャフトの先端部を挿入するに際して、止め輪が環状凹溝に嵌まり込んで確実に縮径できるように環状凹溝の軸方向長さを確保した上で、その環状凹溝のシャフト先端側に軸方向と直交する面に対して平行な壁面を形成したことにより、環状凹溝の係止面を内側継手部材の当接部の係止面に近づけることができ、その分、止め輪の軸方向ガタ量を小さくすることができる。
また、本発明では、内側継手部材の当接部の係止面の傾斜角度βと、シャフトの環状凹溝の係止面の傾斜角度αとの相対角度β−αを８°以下としたことにより、シャフトの引き抜き力が作用しても止め輪が内側継手部材の当接部の係止面に沿って縮径せず、その当接部から離脱しない確実な非分解構造とすることができる。 In other words, when inserting the tip of the shaft into the shaft hole of the inner joint member, after securing the axial length of the annular groove so that the retaining ring fits into the annular groove and can be surely reduced in diameter, By forming a wall surface parallel to the surface perpendicular to the axial direction on the shaft front end side of the annular groove, the engagement surface of the annular groove can be brought closer to the engagement surface of the contact portion of the inner joint member. The amount of play in the axial direction of the retaining ring can be reduced accordingly.
In the present invention, the relative angle β−α between the inclination angle β of the locking surface of the abutting portion of the inner joint member and the inclination angle α of the locking surface of the annular groove of the shaft is 8 ° or less. Thus, even if the pulling force of the shaft is applied, the retaining ring does not reduce the diameter along the locking surface of the contact portion of the inner joint member, and a reliable non-disassembly structure that does not separate from the contact portion can be obtained. .

本発明において、内側継手部材の当接部に形成され軸方向と直交する面に対して傾斜する係止面と、シャフトの環状凹溝の係止面との間で止め輪の軸方向ガタ量を０．５ｍｍ以下とすることが望ましい。このように、止め輪の軸方向ガタ量を０．５ｍｍ以下とすれば、車両における異音、振動の発生を確実に防止することができる。 In the present invention, the axial backlash amount of the retaining ring between the engaging surface formed at the contact portion of the inner joint member and inclined with respect to the surface orthogonal to the axial direction and the engaging surface of the annular groove of the shaft Is preferably 0.5 mm or less. Thus, if the amount of play in the axial direction of the retaining ring is 0.5 mm or less, the generation of abnormal noise and vibration in the vehicle can be reliably prevented.

本発明では、環状凹溝のシャフト先端側でシャフトの外周面から径方向内側へ延びるように形成され、軸方向と直交する面に対して傾斜する係止面に隣接して、軸方向と直交する面に対して平行な壁面を径方向内側へ延びるように形成する。このように、環状凹溝のシャフト先端側に軸方向と直交する面に対して平行な壁面を形成したことにより、軸方向と直交する面に対して傾斜する係止面のみが形成された従来の等速自在継手の場合よりも、シャフトの環状凹溝の係止面と内側継手部材の当接部の係止面との間で止め輪の軸方向ガタ量を小さくすることができる。このように止め輪の軸方向ガタを抑制することで、車両における異音および振動の発生を未然に防止することができる。 In the present invention, it is formed so as to extend radially inward from the outer peripheral surface of the shaft on the shaft front end side of the annular groove, adjacent to the locking surface inclined with respect to the surface orthogonal to the axial direction, and orthogonal to the axial direction. A wall surface parallel to the surface to be extended is formed to extend radially inward. Thus, by forming the wall surface parallel to the surface orthogonal to the axial direction on the shaft front end side of the annular groove, only the locking surface inclined with respect to the surface orthogonal to the axial direction is formed. The amount of play in the axial direction of the retaining ring can be reduced between the engaging surface of the annular groove of the shaft and the engaging surface of the contact portion of the inner joint member, as compared with the constant velocity universal joint. In this way, by suppressing the backlash in the axial direction of the retaining ring, it is possible to prevent the generation of abnormal noise and vibration in the vehicle.

本発明の実施形態で、アンダーカットフリー型の固定式等速自在継手の全体構成を示す断面図である。In an embodiment of the present invention, it is a sectional view showing the whole structure of an undercut free type fixed type constant velocity universal joint. 図１のシャフトを示す断面図である。It is sectional drawing which shows the shaft of FIG. 図２のＡ部を示す部分拡大断面図である。It is a partial expanded sectional view which shows the A section of FIG. 図１の内側継手部材を示す断面図である。It is sectional drawing which shows the inner side coupling member of FIG. 図４のＢ部を示す部分拡大断面図である。It is a partial expanded sectional view which shows the B section of FIG. 図１の止め輪を示す側面図である。It is a side view which shows the retaining ring of FIG. 図１のＣ部を示す部分拡大断面図である。It is a partial expanded sectional view which shows the C section of FIG. 止め輪の軸方向ガタ量を説明するための要部拡大断面図である。It is a principal part expanded sectional view for demonstrating the amount of axial play of a retaining ring. 係止面の相対角度が小さい場合に止め輪に作用する力を説明するための要部拡大断面図である。It is a principal part expanded sectional view for demonstrating the force which acts on a retaining ring when the relative angle of a locking surface is small. 係止面の相対角度が大きい場合に止め輪に作用する力を説明するための要部拡大断面図である。It is a principal part expanded sectional view for demonstrating the force which acts on a retaining ring when the relative angle of a locking surface is large. 相対角度とシャフトの引き抜き力との関係から、シャフトが抜けるか否かの判定結果の一例を示すグラフである。It is a graph which shows an example of the determination result of whether a shaft comes off from the relationship between a relative angle and the drawing-out force of a shaft. 相対角度とシャフトの引き抜き力との関係から、シャフトが抜けるか否かの判定結果の他例を示すグラフである。It is a graph which shows the other example of the determination result of whether a shaft pulls out from the relationship between a relative angle and the drawing-out force of a shaft.

本発明に係る等速自在継手の実施形態を以下に詳述する。以下の実施形態では、固定式等速自在継手の一種であるアンダーカットフリー型等速自在継手（ＵＪ）を例示する。なお、本発明は、アンダーカットフリー型等速自在継手以外の他の固定式等速自在継手であるツェッパ型等速自在継手（ＢＪ）や、摺動式等速自在継手であるダブルオフセット型等速自在継手（ＤＯＪ）、トリポード型等速自在継手（ＴＪ）、クロスグルーブ型等速自在継手にも適用可能である。 Embodiments of the constant velocity universal joint according to the present invention will be described in detail below. In the following embodiments, an undercut free type constant velocity universal joint (UJ), which is a kind of fixed type constant velocity universal joint, is illustrated. The present invention is not limited to the undercut free type constant velocity universal joint, but is a fixed type constant velocity universal joint, such as a Rzeppa type constant velocity universal joint (BJ), a sliding type constant velocity universal joint, a double offset type, etc. It can also be applied to a speed universal joint (DOJ), a tripod type constant velocity universal joint (TJ), and a cross groove type constant velocity universal joint.

この実施形態の等速自在継手は、図１に示すように、外側継手部材１１、内側継手部材１２、ボール１３およびケージ１４で主要部が構成されている。この等速自在継手は、一端が開口したカップ状をなし、軸方向に延びるトラック溝１５が球状内周面１６の複数箇所に円周方向等間隔で形成された外側継手部材１１と、軸方向に延びるトラック溝１７が外側継手部材１１のトラック溝１５と対をなして球状外周面１８の複数箇所に円周方向等間隔で形成された内側継手部材１２と、外側継手部材１１のトラック溝１５と内側継手部材１２のトラック溝１７との間に配されたトルク伝達部材としてのボール１３と、外側継手部材１１の球状内周面１６と内側継手部材１２の球状外周面１８との間に介在してボール１３を保持するケージ１４とを備えた構造を具備する。これら内側継手部材１２、ボール１３およびケージ１４が、外側継手部材１１に収容された内部部品を構成している。なお、ボール１３は６個、８個などその個数は任意である。 As shown in FIG. 1, the constant velocity universal joint according to this embodiment includes an outer joint member 11, an inner joint member 12, a ball 13, and a cage 14. This constant velocity universal joint has a cup shape with one open end, and an outer joint member 11 in which track grooves 15 extending in the axial direction are formed at a plurality of locations on the spherical inner peripheral surface 16 at equal intervals in the circumferential direction, and the axial direction. The track groove 17 extending in the direction of the outer joint member 11 forms a pair with the track groove 15 of the outer joint member 11 and is formed at a plurality of locations on the spherical outer peripheral surface 18 at equal intervals in the circumferential direction, and the track groove 15 of the outer joint member 11. And a ball 13 as a torque transmitting member disposed between the outer joint member 12 and the track groove 17 of the inner joint member 12, and a spherical inner peripheral surface 16 of the outer joint member 11 and a spherical outer peripheral surface 18 of the inner joint member 12. And a cage 14 for holding the ball 13. The inner joint member 12, the ball 13, and the cage 14 constitute an internal part accommodated in the outer joint member 11. The number of balls 13 is arbitrary, such as six or eight.

自動車のドライブシャフトを構成する等速自在継手においては、内側継手部材１２にシャフト１９がスプライン嵌合によりトルク伝達可能に結合されている。このシャフト１９の内側継手部材１２への組み付け作業は、外側継手部材１１の内部に、内側継手部材１２、ボール１３およびケージ１４からなる内部部品を組み込んだ後に行われることから、以下のようなシャフト抜け止め構造を採用している。 In a constant velocity universal joint constituting a drive shaft of an automobile, a shaft 19 is coupled to the inner joint member 12 so as to transmit torque by spline fitting. Since the assembling work of the shaft 19 to the inner joint member 12 is performed after the inner parts composed of the inner joint member 12, the ball 13 and the cage 14 are incorporated into the outer joint member 11, the following shaft Uses a retaining structure.

このシャフト抜け止め構造では、図２および図３に示すように、シャフト１９の先端部に環状凹溝２０を形成すると共に、図４および図５に示すように、内側継手部材１２の軸孔２１の奥側端部に当接部２２を設ける。シャフト１９の内側継手部材１２への組み付け作業では、シャフト１９の環状凹溝２０に弾性的に縮径可能なＣ字形状のサークリップ等の止め輪２３（図６参照）を装着する。内側継手部材１２の軸孔２１にシャフト１９の先端部を挿入してスプライン２４，２５よりトルク伝達可能に嵌合させる。 In this shaft retaining structure, as shown in FIGS. 2 and 3, an annular groove 20 is formed at the tip of the shaft 19, and as shown in FIGS. 4 and 5, the shaft hole 21 of the inner joint member 12. A contact portion 22 is provided at the back end of the. In the assembling work of the shaft 19 to the inner joint member 12, a retaining ring 23 (see FIG. 6) such as a C-shaped circlip that can be elastically reduced in diameter is attached to the annular groove 20 of the shaft 19. The tip end portion of the shaft 19 is inserted into the shaft hole 21 of the inner joint member 12 and is fitted so that torque can be transmitted from the splines 24 and 25.

このシャフト１９の挿入により、環状凹溝２０で縮径状態にある止め輪２３は、内側継手部材１２の当接部２２に達した時点でその弾性復元力により拡径する。このようにして止め輪２３を拡径させることにより内側継手部材１２の当接部２２に係止させる。なお、自由状態での止め輪２３の外径Ｄ１（図６参照）は、内側継手部材１２の当接部２２の内径Ｄ２（図４参照）よりも大きく設定されている。これにより、止め輪２３を内側継手部材１２の当接部２２に確実に係止させることができる。 With the insertion of the shaft 19, the retaining ring 23 that is in a reduced diameter state in the annular groove 20 is expanded in diameter by its elastic restoring force when it reaches the contact portion 22 of the inner joint member 12. In this way, the retaining ring 23 is expanded in diameter to be engaged with the contact portion 22 of the inner joint member 12. The outer diameter D1 (see FIG. 6) of the retaining ring 23 in the free state is set larger than the inner diameter D2 (see FIG. 4) of the contact portion 22 of the inner joint member 12. Thereby, the retaining ring 23 can be reliably locked to the contact portion 22 of the inner joint member 12.

なお、内側継手部材１２の軸孔２１のシャフト挿入側端部にテーパ面２６を形成すると共に、シャフト１９の大径部にテーパ面２７を形成することによりストッパ部２８を構成している。このストッパ部２８により、内側継手部材１２の軸孔２１にシャフト１９を挿入する際、シャフト１９の大径部のテーパ面２７を内側継手部材１２の軸孔２１のシャフト挿入側端部のテーパ面２６に当接させることで、内側継手部材１２に対するシャフト１９の挿入位置を規制するようにしている。 The stopper portion 28 is configured by forming a tapered surface 26 at the shaft insertion side end of the shaft hole 21 of the inner joint member 12 and forming a tapered surface 27 at the large diameter portion of the shaft 19. When the shaft 19 is inserted into the shaft hole 21 of the inner joint member 12 by the stopper portion 28, the tapered surface 27 of the large diameter portion of the shaft 19 is changed to the taper surface of the shaft insertion side end portion of the shaft hole 21 of the inner joint member 12. 26, the insertion position of the shaft 19 with respect to the inner joint member 12 is regulated.

このシャフト抜け止め構造において、シャフト１９の環状凹溝２０のシャフト先端側は、図２および図３に示すように、シャフト１９の外周面から径方向内側へ延びるように形成され、軸方向と直交する面に対して角度αで傾斜する係止面２９（傾斜面）と、その係止面２９に隣接して径方向内側へ延びるように形成され、軸方向と直交する面に対して平行な壁面３０（垂直面）とで構成されている。一方、内側継手部材１２の当接部２２は、図４および図５に示すように、軸孔２１の奥側に位置するスプライン２４の端部に形成され、軸方向と直交する面に対して角度βで傾斜する係止面３１と、その係止面３１から内側継手部材１２の奥側端面まで延びるように形成された円筒面３２とで構成されている。 In this shaft retaining structure, the tip end side of the annular groove 20 of the shaft 19 is formed so as to extend radially inward from the outer peripheral surface of the shaft 19 as shown in FIGS. 2 and 3, and orthogonal to the axial direction. A locking surface 29 (inclined surface) that is inclined at an angle α with respect to the surface to be formed, and is formed so as to extend radially inward adjacent to the locking surface 29 and parallel to the surface orthogonal to the axial direction. It is comprised with the wall surface 30 (vertical surface). On the other hand, the contact portion 22 of the inner joint member 12 is formed at the end of the spline 24 located on the back side of the shaft hole 21 as shown in FIGS. The locking surface 31 is inclined at an angle β, and the cylindrical surface 32 is formed so as to extend from the locking surface 31 to the back end surface of the inner joint member 12.

シャフト１９に引き抜き力が作用した場合、図７に示すように、止め輪２３は、シャフト１９の環状凹溝２０の係止面２９と、内側継手部材１２の当接部２２の係止面３１および円筒面３２とで挟み込まれる。つまり、シャフト１９の環状凹溝２０の係止面２９と接触する止め輪２３が、内側継手部材１２の当接部２２の係止面３１および円筒面３２と接触して係止される。このようにして、シャフト１９が内側継手部材１２に対して抜け止めされる。 When a pulling force is applied to the shaft 19, as shown in FIG. 7, the retaining ring 23 includes a locking surface 29 of the annular groove 20 of the shaft 19 and a locking surface 31 of the contact portion 22 of the inner joint member 12. And the cylindrical surface 32. That is, the retaining ring 23 that contacts the locking surface 29 of the annular groove 20 of the shaft 19 contacts and is locked with the locking surface 31 and the cylindrical surface 32 of the contact portion 22 of the inner joint member 12. In this way, the shaft 19 is prevented from coming off from the inner joint member 12.

前述したように、環状凹溝２０のシャフト先端側では、シャフト１９の外周面から径方向内側へ延びるように形成され、軸方向と直交する面に対して傾斜する係止面２９に隣接して、軸方向と直交する面に対して平行な壁面３０を径方向内側へ延びるように形成したことにより、軸方向と直交する面に対して傾斜する係止面（図３の破線部分）のみが形成された従来の等速自在継手（特許文献１参照）の場合よりも、シャフト１９の環状凹溝２０の係止面２９と内側継手部材１２の当接部２２の係止面３１との間で止め輪２３の軸方向ガタ量を小さくすることができる。 As described above, on the shaft front end side of the annular groove 20, it is formed to extend radially inward from the outer peripheral surface of the shaft 19, and is adjacent to the locking surface 29 that is inclined with respect to the surface orthogonal to the axial direction. By forming the wall surface 30 parallel to the surface orthogonal to the axial direction so as to extend inward in the radial direction, only the locking surface (dashed line portion in FIG. 3) that is inclined with respect to the surface orthogonal to the axial direction is provided. Compared with the formed conventional constant velocity universal joint (refer to Patent Document 1), between the locking surface 29 of the annular groove 20 of the shaft 19 and the locking surface 31 of the contact portion 22 of the inner joint member 12. Thus, the amount of axial play of the retaining ring 23 can be reduced.

つまり、内側継手部材１２の軸孔２１にシャフト１９の先端部を挿入するに際して、止め輪２３が環状凹溝２０に嵌まり込んで確実に縮径できるように環状凹溝２０の軸方向長さを確保した上で、図３の軸方向ガタ減少量δの分だけ、環状凹溝２０の係止面２９を内側継手部材１２の当接部２２の係止面３１に近づけることができ、その分、止め輪２３の軸方向ガタ量を小さくすることができる。ここで、止め輪２３の軸方向ガタ量とは、図８に示すように、止め輪２３とシャフト１９の環状凹溝２０の係止面２９との間の軸方向すきまＳ１、および止め輪２３と内側継手部材１２の当接部２２の係止面３１との間の軸方向すきまＳ２の総和Ｓ１＋Ｓ２を意味する。 That is, when the tip end of the shaft 19 is inserted into the shaft hole 21 of the inner joint member 12, the axial length of the annular groove 20 is such that the retaining ring 23 fits into the annular groove 20 and can be reliably reduced in diameter. 3, the locking surface 29 of the annular groove 20 can be brought closer to the locking surface 31 of the contact portion 22 of the inner joint member 12 by the amount of axial play reduction δ in FIG. Therefore, the amount of axial play of the retaining ring 23 can be reduced. Here, the axial backlash amount of the retaining ring 23 refers to the axial clearance S1 between the retaining ring 23 and the locking surface 29 of the annular groove 20 of the shaft 19 and the retaining ring 23 as shown in FIG. And the sum S1 + S2 of the axial clearance S2 between the contact surface 22 of the contact portion 22 of the inner joint member 12 and the inner joint member 12.

図８では、止め輪２３とシャフト１９の環状凹溝２０の係止面２９との軸方向すきまＳ１、および止め輪２３と内側継手部材１２の当接部２２の係止面３１との軸方向すきまＳ２を誇張して示しているが、これら軸方向すきまＳ１，Ｓ２の総和である軸方向ガタ量、つまり、内側継手部材１２の当接部２２の係止面３１とシャフト１９の環状凹溝２０の係止面２９との間の軸方向ガタ量は０．５ｍｍ以下がよい。 In FIG. 8, the axial clearance S1 between the retaining ring 23 and the retaining surface 29 of the annular groove 20 of the shaft 19, and the axial direction between the retaining ring 23 and the retaining surface 31 of the contact portion 22 of the inner joint member 12. Although the clearance S2 is exaggerated, the axial backlash, which is the sum of the axial clearances S1 and S2, that is, the locking surface 31 of the contact portion 22 of the inner joint member 12 and the annular concave groove of the shaft 19 is shown. The axial backlash between the 20 locking surfaces 29 is preferably 0.5 mm or less.

この程度に軸方向ガタ量が小さければ、車両における異音、振動の発生を確実に防止することができる。なお、本出願人が実車による異音、振動の発生状況を確認したところ、軸方向ガタ量が０．５ｍｍよりも大きく、１．０ｍｍよりも小さい場合、車両や走行条件により異音や振動が発生する場合があり、軸方向ガタ量が１．０ｍｍよりも大きいと、車両や走行条件により異音や振動が高い確率で発生することが判明した。 If the amount of axial play is small, it is possible to reliably prevent the generation of abnormal noise and vibration in the vehicle. In addition, when the applicant confirmed the occurrence of abnormal noise and vibration due to the actual vehicle, when the axial backlash amount is larger than 0.5 mm and smaller than 1.0 mm, the abnormal noise and vibration may be generated depending on the vehicle and running conditions. When the amount of axial backlash is greater than 1.0 mm, it has been found that abnormal noise and vibration are generated with high probability depending on the vehicle and running conditions.

また、シャフト１９の環状凹溝２０において係止面２９と壁面３０との境界位置も重要である。つまり、図７に示すように、シャフト１９の環状凹溝２０の係止面２９の止め輪接触点Ｐと、その係止面２９に隣接する壁面３０との境界点Ｑとの間の長さＬは０．３ｍｍ≦Ｌ≦１．０ｍｍがよい。 Further, the boundary position between the locking surface 29 and the wall surface 30 in the annular groove 20 of the shaft 19 is also important. That is, as shown in FIG. 7, the length between the retaining ring contact point P of the locking surface 29 of the annular groove 20 of the shaft 19 and the boundary point Q between the wall surface 30 adjacent to the locking surface 29. L is preferably 0.3 mm ≦ L ≦ 1.0 mm.

この止め輪接触点Ｐと境界点Ｑとの長さＬが０．３ｍｍよりも小さいと（Ｌ＜０．３ｍｍ）、シャフト１９に衝撃的な引き抜き力が作用した場合、止め輪２３が突発的に内側継手部材１２の当接部２２の係止面３１に沿って縮径してシャフト１９が内側継手部材１２から抜けてしまうおそれがある。一方、止め輪接触点Ｐと境界点Ｑとの長さＬが１．０ｍｍよりも大きいと（Ｌ＞１．０ｍｍ）、環状凹溝２０の係止面２９が内側継手部材１２の当接部２２の係止面３１から軸方向に離間することになり、前述の軸方向ガタ量が大きくなる。 If the length L between the retaining ring contact point P and the boundary point Q is smaller than 0.3 mm (L <0.3 mm), the retaining ring 23 will suddenly occur when a shocking pulling force acts on the shaft 19. Further, the shaft 19 may come out of the inner joint member 12 due to a diameter reduction along the locking surface 31 of the contact portion 22 of the inner joint member 12. On the other hand, when the length L between the retaining ring contact point P and the boundary point Q is larger than 1.0 mm (L> 1.0 mm), the locking surface 29 of the annular groove 20 is a contact portion of the inner joint member 12. Accordingly, the above-described axial play is increased.

従って、止め輪接触点Ｐと境界点Ｑとの間の長さＬを０．３ｍｍ≦Ｌ≦１．０ｍｍとすることにより、シャフト１９に衝撃的な引き抜き力が作用しても止め輪２３が不所望に縮径することがなく、シャフト１９を内側継手部材１２に確実に抜け止めすることができ、止め輪２３の軸方向ガタも確実に抑制することができる。 Therefore, by setting the length L between the retaining ring contact point P and the boundary point Q to 0.3 mm ≦ L ≦ 1.0 mm, the retaining ring 23 can be moved even if an impact pulling force acts on the shaft 19. Without undesirably reducing the diameter, the shaft 19 can be reliably prevented from coming off the inner joint member 12, and the axial play of the retaining ring 23 can also be reliably suppressed.

この等速自在継手では、ブーツ交換などの整備工数の簡略化を図るため、分解可能な仕様あるいは分解不可能な仕様に応じて、内側継手部材１２とシャフト１９との分解構造と非分解構造とを選択可能としたシャフト抜け止め構造を採用する。このシャフト抜け止め構造では、図７に示すように、シャフト１９の環状凹溝２０の係止面２９の傾斜角度α（図３参照）と、内側継手部材１２の当接部２２の係止面３１の傾斜角度β（図５参照）との相対角度β−αを規定する。 In this constant velocity universal joint, in order to simplify maintenance man-hours such as replacement of boots, the disassembled structure of the inner joint member 12 and the shaft 19 and the non-disassembled structure according to the specifications that can be disassembled or the specifications that cannot be disassembled. Adopting a shaft retaining structure that can be selected. In this shaft retaining structure, as shown in FIG. 7, the inclination angle α (see FIG. 3) of the locking surface 29 of the annular groove 20 of the shaft 19 and the locking surface of the contact portion 22 of the inner joint member 12. A relative angle β-α with respect to an inclination angle β of 31 (see FIG. 5) is defined.

この相対角度β−αが小さい場合、図９に示すように、シャフト１９に引き抜き力が作用した時、内側継手部材１２の当接部２２の係止面３１から受ける縮径方向の分力ＦＮと、シャフト１９の環状凹溝２０の係止面２９から受ける拡径方向の分力ＦＳとの差が小さいため、止め輪２３の弾性力でもって当接部２２への係止状態を維持することができ、止め輪２３は縮径されずにシャフト１９と内側継手部材１２とが分解不可能な非分解構造となる。 When this relative angle β−α is small, as shown in FIG. 9, when a pulling force is applied to the shaft 19, a component force FN in the reduced diameter direction received from the locking surface 31 of the contact portion 22 of the inner joint member 12. And the component force FS in the diameter increasing direction received from the locking surface 29 of the annular groove 20 of the shaft 19 is small, so that the locking state to the contact portion 22 is maintained by the elastic force of the retaining ring 23. The retaining ring 23 is not reduced in diameter and has a non-decomposed structure in which the shaft 19 and the inner joint member 12 cannot be disassembled.

逆に、相対角度β−αが大きい場合、図１０に示すように、シャフト１９に引き抜き力が作用した時、内側継手部材１２の当接部２２の係止面３１から受ける縮径方向の分力ＦＮと、シャフト１９の環状凹溝２０の係止面２９から受ける拡径方向の分力ＦＳとの差が大きいため（ＦＮ＞ＦＳ）、止め輪２３の弾性力でもって当接部２２への係止状態を維持することができず、止め輪２３は縮径されてシャフト１９と内側継手部材１２とが分解可能な分解構造となる。 On the other hand, when the relative angle β-α is large, as shown in FIG. 10, when the pulling force is applied to the shaft 19, the amount in the reduced diameter direction received from the locking surface 31 of the contact portion 22 of the inner joint member 12. Since the difference between the force FN and the component force FS in the diameter-expanding direction received from the engaging surface 29 of the annular groove 20 of the shaft 19 is large (FN> FS), the elastic force of the retaining ring 23 leads to the contact portion 22. The retaining ring 23 is reduced in diameter so that the shaft 19 and the inner joint member 12 can be disassembled.

ここで、本出願人が検証したところ、特許文献１に開示された環状凹溝の係止面の傾斜角度αと当接部の係止面の傾斜角度βとの相対角度β−αの範囲（β−α≦１９°）では、シャフトの引き抜き力が作用しても止め輪の縮径を抑制することが困難な場合があり、確実な非分解構造であるとは言えないことが判明した。そこで、この実施形態の等速自在継手では、内側継手部材１２の当接部２２の係止面３１の傾斜角度βと、シャフト１９の環状凹溝２０の係止面２９の傾斜角度αとの相対角度β−αを８°以下とする。 Here, as a result of verification by the present applicant, the range of the relative angle β−α between the inclination angle α of the engaging surface of the annular groove and the inclination angle β of the engaging surface of the contact portion disclosed in Patent Document 1. (Β−α ≦ 19 °), it has been found that it is difficult to suppress the diameter reduction of the retaining ring even when the pulling force of the shaft acts, and it cannot be said that it is a reliable non-decomposed structure. . Therefore, in the constant velocity universal joint of this embodiment, the inclination angle β of the locking surface 31 of the abutting portion 22 of the inner joint member 12 and the inclination angle α of the locking surface 29 of the annular groove 20 of the shaft 19 are determined. The relative angle β-α is set to 8 ° or less.

このように、内側継手部材１２の当接部２２の係止面３１の傾斜角度βと、シャフト１９の環状凹溝２０の係止面２９の傾斜角度αとの相対角度β−αを８°以下とすることにより（０°＜β−α≦８°）、シャフト１９の引き抜き力が作用しても止め輪２３が内側継手部材１２の当接部２２の係止面３１に沿って縮径せず、その当接部２２から離脱しない確実な非分解構造とすることができる。なお、β−α≦０°の場合には、内側継手部材１２の当接部２２の係止面３１から受ける縮径方向の分力ＦＮよりも、シャフト１９の環状凹溝２０の係止面２９から受ける拡径方向の分力ＦＳの方が大きくなるため（ＦＮ＜ＦＳ）、止め輪２３が縮径せずに分解不可能な非分解構造となる。 Thus, the relative angle β−α between the inclination angle β of the locking surface 31 of the contact portion 22 of the inner joint member 12 and the inclination angle α of the locking surface 29 of the annular groove 20 of the shaft 19 is 8 °. By setting as below (0 ° <β−α ≦ 8 °), the retaining ring 23 is reduced in diameter along the locking surface 31 of the abutting portion 22 of the inner joint member 12 even when the pulling force of the shaft 19 is applied. Therefore, a reliable non-decomposing structure that does not separate from the contact portion 22 can be obtained. When β−α ≦ 0 °, the locking surface of the annular groove 20 of the shaft 19 is larger than the component force FN in the reduced diameter direction received from the locking surface 31 of the contact portion 22 of the inner joint member 12. Since the component force FS in the diameter-expanding direction received from 29 becomes larger (FN <FS), the retaining ring 23 has a non-decomposable structure that cannot be disassembled without reducing its diameter.

本出願人が検証した結果として、相対角度β−αとシャフト１９の引き抜き力との関係から、シャフト１９と内側継手部材１２とが分解可能か否かを判定した結果を図１１および図１２に示す。つまり、シャフト１９の止め輪２３を内側継手部材１２の当接部２２に係止させた後、シャフト１９に引き抜き力を作用させた時に、そのシャフト１９が抜けるか否かを実験したものである。縦軸の引き抜き力は、抜けた場合の抜け荷重、抜けなかった場合の最大荷重である。図１１の丸印は線径がφ１．６ｍｍの止め輪２３を使用した例であり、図１２の四角印は線径がφ１．８ｍｍの止め輪２３を使用し、三角印は線径がφ２．３ｍｍの止め輪２３を使用した例である。 As a result of verification by the present applicant, FIG. 11 and FIG. 12 show the results of determining whether the shaft 19 and the inner joint member 12 can be disassembled from the relationship between the relative angle β-α and the pulling force of the shaft 19. Show. That is, after the retaining ring 23 of the shaft 19 is locked to the contact portion 22 of the inner joint member 12, whether or not the shaft 19 is pulled out when an extraction force is applied to the shaft 19 is tested. . The pull-out force on the vertical axis is the pull-out load when it is pulled out, and the maximum load when it is not pulled out. The circle mark in FIG. 11 is an example using a retaining ring 23 with a wire diameter of φ1.6 mm, the square mark in FIG. 12 uses the retaining ring 23 with a wire diameter of φ1.8 mm, and the triangular mark has a wire diameter of φ2 mm. This is an example in which a 3 mm retaining ring 23 is used.

図１１および図１２に示すように、止め輪２３の線径の大小にかかわらず、相対角度β−αが８°以下であれば、シャフト１９と内側継手部材１２とが分解不可能な非分解構造となっていることが明らかである。なお、相対角度β−αが１０°の場合、抜けるものと抜けないものとが混在していることから、この相対角度β−αが１０°近辺が分解構造と非分解構造との境界であることが確認できる。 As shown in FIGS. 11 and 12, the shaft 19 and the inner joint member 12 cannot be disassembled if the relative angle β-α is 8 ° or less, regardless of the wire diameter of the retaining ring 23. It is clear that it has a structure. In addition, when the relative angle β-α is 10 °, there are a mixture of those that are missing and those that are not missing. Therefore, the relative angle β-α near 10 ° is a boundary between the decomposition structure and the non-decomposition structure. I can confirm that.

なお、相対角度β−αを８°、好ましくは１０°よりも大きくすることにより、シャフト１９と内側継手部材１２とが分解可能な分解構造とすることができる。この分解構造における内側継手部材１２を非分解構造の等速自在継手に共通して使用する場合、その内側継手部材１２の当接部２２の係止面３１の傾斜角度βとの相対角度β−αが８°以下となるように、環状凹溝２０の係止面２９の傾斜角度αを選定したシャフト１９を用いればよい。このようにして、前述した分解構造の内側継手部材１２との組み合わせであっても確実な非分解構造とすることが可能となる。この非分解構造におけるシャフト１９の環状凹溝２０の係止面２９の傾斜角度αは、分解構造で使用するシャフト１９（傾斜角度α＝０°）と視認性よく区別できて容易に管理することができるように、１５°以上とすることが好ましい。 In addition, it can be set as the decomposition | disassembly structure which can disassemble the shaft 19 and the inner joint member 12 by making relative angle (beta)-(alpha) larger than 8 degrees, Preferably it is 10 degrees. When the inner joint member 12 in this disassembled structure is commonly used for a constant velocity universal joint in a non-decomposed structure, the relative angle β− with respect to the inclination angle β of the locking surface 31 of the contact portion 22 of the inner joint member 12. What is necessary is just to use the shaft 19 which selected the inclination | tilt angle (alpha) of the locking surface 29 of the annular groove 20 so that (alpha) might be 8 degrees or less. In this way, a reliable non-decomposed structure can be obtained even in combination with the inner joint member 12 having the above-described disassembled structure. The inclination angle α of the locking surface 29 of the annular groove 20 of the shaft 19 in this non-decomposed structure can be easily managed by distinguishing with good visibility from the shaft 19 (inclination angle α = 0 °) used in the exploded structure. Is preferably 15 ° or more so that the

本発明は前述した実施形態に何ら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内において、さらに種々なる形態で実施し得ることは勿論のことであり、本発明の範囲は、特許請求の範囲によって示され、さらに特許請求の範囲に記載の均等の意味、および範囲内のすべての変更を含む。 The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the gist of the present invention. It includes the equivalent meanings recited in the claims and the equivalents recited in the claims, and all modifications within the scope.

１１外側継手部材
１２内側継手部材
１３トルク伝達部材（ボール）
１９シャフト
２０環状凹溝
２１軸孔
２２当接部
２３止め輪
２９係止面
３０壁面
３１係止面
α，β 傾斜角度
Ｐ止め輪接触点
Ｑ境界点 11 outer joint member 12 inner joint member 13 torque transmission member (ball)
19 Shaft 20 Annular groove 21 Shaft hole 22 Abutting portion 23 Retaining ring 29 Engaging surface 30 Wall surface 31 Engaging surface α, β Inclination angle P Retaining ring contact point Q Boundary point

Claims

外側継手部材と、前記外側継手部材との間でトルク伝達部材を介して角度変位を許容しながらトルクを伝達する内側継手部材とを備え、前記内側継手部材の軸孔にシャフトの先端部を挿入してトルク伝達可能に嵌合させ、前記シャフトの環状凹溝に弾性的に縮径可能に装着された止め輪を、前記内側継手部材の軸孔端部に形成された当接部に係止させることにより、内側継手部材に対してシャフトを抜け止めする等速自在継手であって、
前記環状凹溝のシャフト先端側は、前記シャフトの外周面から径方向内側へ延びるように形成され軸方向と直交する面に対して傾斜する係止面と、前記係止面に隣接して径方向内側に延びるように形成され軸方向と直交する面に対して平行な壁面とで構成され、シャフトへの引き抜き力の作用時、止め輪は、シャフトの環状凹溝の係止面と、前記内側継手部材の当接部の係止面および円筒面とで挟み込まれ、前記内側継手部材の当接部の係止面の傾斜角度βと、前記シャフトの環状凹溝の係止面の傾斜角度αとの相対角度β−αを８°以下としたことを特徴とする等速自在継手。 An outer joint member, and an inner joint member that transmits torque while allowing angular displacement between the outer joint member and the outer joint member, and the shaft tip is inserted into the shaft hole of the inner joint member Then, a retaining ring that is fitted so as to be able to transmit torque and is elastically retractable in the annular groove of the shaft is locked to a contact portion formed at the end of the shaft hole of the inner joint member. A constant velocity universal joint that prevents the shaft from coming off against the inner joint member,
A shaft front end side of the annular groove has a locking surface formed so as to extend radially inward from the outer peripheral surface of the shaft and inclined with respect to a surface orthogonal to the axial direction, and has a diameter adjacent to the locking surface. The wall is formed to extend inward in the direction and is parallel to the surface orthogonal to the axial direction, and when the pulling force is applied to the shaft, the retaining ring includes the locking surface of the annular groove in the shaft, The angle of inclination β of the locking surface of the abutting portion of the inner joint member and the angle of inclination of the locking surface of the annular groove of the shaft are sandwiched between the locking surface and the cylindrical surface of the abutting portion of the inner joint member A constant velocity universal joint characterized in that a relative angle β-α to α is 8 ° or less .

前記内側継手部材の当接部に形成され軸方向と直交する面に対して傾斜する係止面と、前記シャフトの環状凹溝の係止面との間で前記止め輪の軸方向ガタ量を０．５ｍｍ以下とした請求項１に記載の等速自在継手。 The amount of axial backlash of the retaining ring between the locking surface formed at the contact portion of the inner joint member and inclined with respect to the surface orthogonal to the axial direction and the locking surface of the annular groove of the shaft. The constant velocity universal joint according to claim 1, wherein the constant velocity universal joint is 0.5 mm or less.