JP5834968B2 - Cross shaft type universal joint - Google Patents

Cross shaft type universal joint Download PDF

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Publication number
JP5834968B2
JP5834968B2 JP2012017148A JP2012017148A JP5834968B2 JP 5834968 B2 JP5834968 B2 JP 5834968B2 JP 2012017148 A JP2012017148 A JP 2012017148A JP 2012017148 A JP2012017148 A JP 2012017148A JP 5834968 B2 JP5834968 B2 JP 5834968B2
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shaft
cross
portions
base
yokes
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JP2013155806A (en
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誠一 森山
誠一 森山
前田　篤志
篤志 前田
泰志 重田
泰志 重田
定方　清
清 定方
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NSK Ltd
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NSK Ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D3/00—Yielding couplings, i.e. with means permitting movement between the connected parts during the drive
    • F16D3/16—Universal joints in which flexibility is produced by means of pivots or sliding or rolling connecting parts
    • F16D3/26—Hooke's joints or other joints with an equivalent intermediate member to which each coupling part is pivotally or slidably connected
    • F16D3/38—Hooke's joints or other joints with an equivalent intermediate member to which each coupling part is pivotally or slidably connected with a single intermediate member with trunnions or bearings arranged on two axes perpendicular to one another
    • F16D3/382—Hooke's joints or other joints with an equivalent intermediate member to which each coupling part is pivotally or slidably connected with a single intermediate member with trunnions or bearings arranged on two axes perpendicular to one another constructional details of other than the intermediate member
    • F16D3/385—Bearing cup; Bearing construction; Bearing seal; Mounting of bearing on the intermediate member
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D3/00—Yielding couplings, i.e. with means permitting movement between the connected parts during the drive
    • F16D3/16—Universal joints in which flexibility is produced by means of pivots or sliding or rolling connecting parts
    • F16D3/26—Hooke's joints or other joints with an equivalent intermediate member to which each coupling part is pivotally or slidably connected
    • F16D3/38—Hooke's joints or other joints with an equivalent intermediate member to which each coupling part is pivotally or slidably connected with a single intermediate member with trunnions or bearings arranged on two axes perpendicular to one another
    • F16D3/40—Hooke's joints or other joints with an equivalent intermediate member to which each coupling part is pivotally or slidably connected with a single intermediate member with trunnions or bearings arranged on two axes perpendicular to one another with intermediate member provided with two pairs of outwardly-directed trunnions on intersecting axes
    • F16D3/41—Hooke's joints or other joints with an equivalent intermediate member to which each coupling part is pivotally or slidably connected with a single intermediate member with trunnions or bearings arranged on two axes perpendicular to one another with intermediate member provided with two pairs of outwardly-directed trunnions on intersecting axes with ball or roller bearings

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Sealing Of Bearings (AREA)

Description

この発明は、例えばステアリングシャフトの動きをステアリングギヤに伝達する為、自動車のステアリング装置に組み込んだ状態で使用する十字軸式自在継手の改良に関する。具体的には、十字軸を構成する４本の軸部の基端部の疲労強度を向上させる事により、この十字軸を組み込んだ十字軸式自在継手の信頼性及び耐久性の向上、或いは小型・軽量化を可能にするものである。   The present invention relates to an improvement in a cross shaft type universal joint that is used in a state where it is incorporated in a steering device of an automobile, for example, in order to transmit the movement of a steering shaft to a steering gear. Specifically, by improving the fatigue strength of the base end portion of the four shaft portions constituting the cross shaft, the reliability and durability of the cross shaft universal joint incorporating this cross shaft is improved, or a small size・ It is possible to reduce the weight.

自動車のステアリング装置は、例えば特許文献１に記載されている如く、図７に示す様に構成している。運転者が操作するステアリングホイール１の動きは、ステアリングシャフト２、自在継手３、中間シャフト４、別の自在継手３を介して、ステアリングギヤユニット５の入力軸６に伝達される。そして、このステアリングギヤユニット５に内蔵したラック＆ピニオン機構により左右１対のタイロッド７、７を押し引きし、左右１対の操舵輪（一般的には前輪）に、前記ステアリングホイール１の操作量に応じて、適切な舵角を付与する様に構成している。   An automobile steering device is configured as shown in FIG. 7 as described in Patent Document 1, for example. The movement of the steering wheel 1 operated by the driver is transmitted to the input shaft 6 of the steering gear unit 5 through the steering shaft 2, the universal joint 3, the intermediate shaft 4, and another universal joint 3. A pair of left and right tie rods 7 and 7 are pushed and pulled by a rack and pinion mechanism built in the steering gear unit 5, and the amount of operation of the steering wheel 1 is applied to a pair of left and right steering wheels (generally, front wheels). Depending on the situation, an appropriate rudder angle is provided.

この様なステアリング装置に組み込む自在継手として一般的には、カルダン継手と呼ばれる十字軸継手が、広く使用されている。図８〜９は、前記特許文献１に記載される等により、従来から広く知られている自在継手の１例を示している。尚、図８〜９に示した構造は、振動の伝達を防止する、所謂防振継手であるが、本発明の対象となる自在継手は、必ずしも防振構造を具備する必要はない。そこで、以下の説明は防振構造を省略して、自在継手３の本体部分の構造に就いて行う。   In general, a cross joint called a cardan joint is widely used as a universal joint incorporated in such a steering apparatus. 8 to 9 show an example of a universal joint that has been widely known so far, as described in Patent Document 1 above. The structures shown in FIGS. 8 to 9 are so-called vibration-proof joints that prevent transmission of vibration, but the universal joint that is the subject of the present invention does not necessarily have to have a vibration-proof structure. Therefore, the following description will be made on the structure of the main body portion of the universal joint 3 while omitting the vibration-proof structure.

この自在継手３は、十分な剛性を有する金属材によりそれぞれが二又状に形成された１対のヨーク８ａ、８ｂと、軸受鋼の如き合金鋼等の硬質金属により造られた十字軸９とから構成される。これら両ヨーク８ａ、８ｂの両端部には、互いに同心の円孔１０、１０を形成している。そしてこれら各円孔１０、１０に、やはり軸受鋼、肌焼鋼等の硬質金属製の板材により有底円筒状に造られた軸受カップ１１、１１を、互いの開口を対向させた状態で内嵌固定している。又、前記十字軸９は、１対の柱部の中間部同士を互いに直交させた如き形状を有し、それぞれが円柱状である、４箇所の軸部１２、１２を有する。即ち、中心部に設けた結合基部１３の円周方向等間隔４箇所位置に、それぞれ前記各軸部１２、１２の基端部を結合固定している。これら各軸部１２、１２の中心軸は、同一平面上に存在する。   The universal joint 3 includes a pair of yokes 8a and 8b each formed in a bifurcated shape by a metal material having sufficient rigidity, and a cross shaft 9 made of a hard metal such as an alloy steel such as bearing steel. Consists of Concentric holes 10 and 10 are formed at both ends of both yokes 8a and 8b. And in these circular holes 10 and 10, bearing cups 11 and 11 made of a hard metal plate material such as bearing steel and case-hardened steel are formed in a state where the openings face each other. It is fitted and fixed. Further, the cross shaft 9 has a shape such that intermediate portions of a pair of column portions are orthogonal to each other, and has four shaft portions 12 and 12 each having a cylindrical shape. That is, the base end portions of the shaft portions 12 and 12 are fixedly connected to four positions at equal intervals in the circumferential direction of the connecting base portion 13 provided in the center portion. The central axes of these shaft portions 12 and 12 exist on the same plane.

この様な各軸部１２、１２の軸方向中間部乃至先端部は、前記各軸受カップ１１、１１内に挿入している。そして、これら各軸受カップ１１、１１の内周面と前記各軸部１２、１２の先半部外周面との間に、ニードル軸受等のラジアル軸受１４、１４を設け、前記十字軸９に対して前記両ヨーク８ａ、８ｂが、軽い力で揺動変位する様にしている。この様に構成する為、これら両ヨーク８ａ、８ｂの中心軸同士が一致しない状態でも、これら両ヨーク８ａ、８ｂの間で回転力の伝達を、伝達ロスを僅少に抑えた状態で行える。   The axial direction intermediate part thru | or the front-end | tip part of each such axial part 12 and 12 are inserted in each said bearing cup 11 and 11. FIG. Then, radial bearings 14, 14 such as needle bearings are provided between the inner peripheral surfaces of the bearing cups 11, 11 and the front half outer peripheral surfaces of the shaft portions 12, 12. Thus, the yokes 8a and 8b are oscillated and displaced with a light force. Due to such a configuration, even when the central axes of the yokes 8a and 8b do not coincide with each other, the rotational force can be transmitted between the yokes 8a and 8b with little transmission loss.

上述の様な自在継手３、３のうち、車室外に設置する（図７で下側の）自在継手３の場合には、前記十字軸９を構成する前記各軸部１２、１２の基端部（前記結合基部１３側の端部）と前記各軸受カップ１１、１１の開口部との間に、それぞれシールリング１５、１５を設けている。そして、これら各シールリング１５、１５により、前記各ラジアル軸受１４、１４の設置部分に泥水等が進入するのを防止し、前記自在継手３の耐久性の確保を図っている。前記各シールリング１５、１５はそれぞれ、金属製で円環状の芯金１６と、ゴムの如きエラストマー製の弾性材１７とから成る。このうちの芯金１６は、軟鋼板等の金属板を曲げ形成する事により、断面Ｌ字形で全体を円環状に形成したもので、円輪部１８と、この円輪部１８の内周縁側から前記各軸部１２、１２の先端側に向けて折れ曲がった円筒部１９とから成る、断面Ｌ字形としている。又、前記弾性材１７は、前記芯金１６を包埋する事でこの芯金１６により補強された基部２０と、この基部２０から延出した、それぞれが特許請求の範囲に記載したシールリップである、ラジアルシールリップ２１とスラストシールリップ２２とから成る。   Among the universal joints 3 and 3 as described above, in the case of the universal joint 3 installed on the outside of the passenger compartment (lower side in FIG. 7), the base ends of the shaft portions 12 and 12 constituting the cross shaft 9 Seal rings 15 and 15 are provided between the portion (the end on the coupling base 13 side) and the opening of each of the bearing cups 11 and 11, respectively. The seal rings 15 and 15 prevent muddy water and the like from entering the installed portions of the radial bearings 14 and 14, thereby ensuring the durability of the universal joint 3. Each of the seal rings 15 and 15 is made of a metal-made annular cored bar 16 and an elastic material 17 made of elastomer such as rubber. Of these, the core 16 is formed by bending a metal plate such as a mild steel plate to form an annular shape as a whole with an L-shaped cross section, and an inner peripheral side of the annular portion 18. The cylindrical section 19 is bent toward the tip end side of each of the shaft sections 12 and 12 and has an L-shaped cross section. The elastic member 17 includes a base 20 reinforced by the core 16 by embedding the core 16, and a seal lip described in the claims, each extending from the base 20. A radial seal lip 21 and a thrust seal lip 22 are provided.

それぞれがこの様な構成を有する、前記各シールリング１５、１５は、前記芯金１６を包埋した基部を前記各軸部１２、１２の基端部に締り嵌めで（弾性材１７の一部を弾性変形させた状態で）外嵌する事により、これら各軸部１２、１２の基端部に、嵌合部のシール性を確保した状態で支持している。この様にこれら各軸部１２、１２の基端部に前記各シールリング１５、１５を支持し、前記十字軸９と前記各軸受カップ１１、１１とを組み合わせた状態で、前記各シールリップ２１、２２のうちのラジアルシールリップ２１のシール縁は、前記各軸受カップ１１、１１の外周面のうちで開口寄り端部に、全周に亙り弾性的に当接する。又、前記スラストシールリップ２２のシール縁は、前記各軸受カップ１１、１１の開口部に形成された内向鍔部２３の外面（前記結合基部１３に対向する面）に、全周に亙り弾性的に当接する。   Each of the seal rings 15, 15 having such a structure is formed by tightening a base portion embedding the cored bar 16 to a base end portion of each of the shaft portions 12, 12 (part of the elastic material 17. By being externally fitted (in a state of being elastically deformed), the base end portions of the shaft portions 12 and 12 are supported in a state in which the sealing performance of the fitting portions is ensured. In this way, the seal rings 15 and 15 are supported on the base end portions of the shaft portions 12 and 12, and the seal lips 21 are combined with the cross shaft 9 and the bearing cups 11 and 11. , 22, the seal edge of the radial seal lip 21 is elastically in contact with the end near the opening of the outer peripheral surfaces of the bearing cups 11 and 11 over the entire circumference. Further, the seal edge of the thrust seal lip 22 is elastic over the entire circumference on the outer surface of the inward flange portion 23 formed on the opening of each of the bearing cups 11 and 11 (the surface facing the coupling base portion 13). Abut.

更に、前記各軸部１２、１２の中心部にはそれぞれ有底の挿入孔２４、２４を、これら各軸部１２、１２の先端面に開口する状態で、前記各軸部１２、１２の軸方向に形成している。そして、これら各挿入孔２４、２４の内側に、合成樹脂製のピン２５、２５を挿入している。これら各ピン２５、２５は、前記各軸受カップ１１、１１と前記各軸部１２、１２との間で突っ張る事により、これら各軸受カップ１１、１１の開口端部と前記基部１３との距離が縮まり過ぎる事を防止する。そして、前記各シーリング１５、１５のスラストシールリップ２２が過度に圧縮されたり、反対に圧縮量が低下し過ぎる事を防止する。即ち、自在継手３の使用時に前記十字軸９と前記各軸受カップ１１、１１との間に加わるスラスト荷重に基づき、スラスト荷重作用側（アンカ側）のシールリング１５が過度に圧縮されて耐久性が損なわれ、反対側（反アンカ側）のシールリング１５の圧縮量が低下し過ぎて、このシールリング１５によるシール性が損なわれる事を防止する。   In addition, bottomed insertion holes 24 and 24 are opened at the center portions of the shaft portions 12 and 12, respectively, so that the shafts of the shaft portions 12 and 12 are opened. It is formed in the direction. And synthetic resin pins 25 and 25 are inserted inside the respective insertion holes 24 and 24. The pins 25 and 25 are stretched between the bearing cups 11 and 11 and the shafts 12 and 12, so that the distance between the opening end of the bearing cups 11 and 11 and the base 13 is increased. Preventing it from shrinking too much. Then, the thrust seal lip 22 of each of the seals 15 and 15 is prevented from being excessively compressed, and conversely, the amount of compression is prevented from being excessively reduced. That is, when the universal joint 3 is used, the thrust load acting side (anchor side) seal ring 15 is excessively compressed on the basis of the thrust load applied between the cross shaft 9 and the bearing cups 11, 11. Is prevented, and the amount of compression of the seal ring 15 on the opposite side (anti-anchor side) is excessively reduced, thereby preventing the sealing performance of the seal ring 15 from being impaired.

但し、上述の様なピン２５、２５を設けない、十字軸式の自在継手に就いても、従来から広く知られている。即ち、図１０に示した従来構造の第２例の如く、軸受カップ１１ａの底部２６の内面中央寄り部分に突条２７、２７を形成し、これら各突条２７、２７の先端縁を、十字軸９を構成する軸部１２の先端面に当接させている。この様な構造によっても、自在継手の構成部材の寸法精度及び組立精度を確保さえすれば、前記軸受カップ１１ａと前記軸部１２との間に設けるシールリング１５の圧縮量を適性範囲に保持できる。   However, a cross shaft type universal joint that does not have the pins 25 and 25 as described above is also widely known. That is, as in the second example of the conventional structure shown in FIG. 10, the ridges 27, 27 are formed near the center of the inner surface of the bottom 26 of the bearing cup 11a, and the tip edges of these ridges 27, 27 are cross-shaped. It is made to contact | abut to the front end surface of the axial part 12 which comprises the axis | shaft 9. As shown in FIG. Even with such a structure, the compression amount of the seal ring 15 provided between the bearing cup 11a and the shaft portion 12 can be maintained within an appropriate range as long as the dimensional accuracy and assembly accuracy of the components of the universal joint are ensured. .

何れの構造の場合でも、十字軸９を構成する軸部１２、１２の基端部にシールリング１５、１５を、締り嵌めで外嵌支持する。そして、これら各軸部１２、１２に対するこれら各シールリング１５、１５の位置決めを適正にする事が、十字軸式の自在継手３の変位抵抗を抑えると共に、これら各シールリング１５、１５のシール性能を確保する面から重要になる。これらの事を考慮すると、図８〜１０に示した従来構造では、十字軸式自在継手に関して、十分な信頼性及び耐久性を確保しつつ、小型・軽量化を図る事が難しい。この点に就いて、図１１を参照しつつ説明する。   In any structure, the seal rings 15 and 15 are externally supported by interference fitting at the base end portions of the shaft portions 12 and 12 constituting the cross shaft 9. The proper positioning of the seal rings 15 and 15 with respect to the shaft portions 12 and 12 suppresses the displacement resistance of the cruciform universal joint 3 and the sealing performance of the seal rings 15 and 15. It becomes important from the aspect of securing. In consideration of these matters, it is difficult to reduce the size and weight of the cross shaft universal joint while ensuring sufficient reliability and durability in the conventional structure shown in FIGS. This point will be described with reference to FIG.

十字軸９を構成する軸部１２のうち、軸方向中間部乃至先端部である、図１１のＬ範囲部分は、ラジアル軸受１４（図８〜１０参照）の内輪軌道としての役目を有する為、超仕上等の研削加工を施す。十字軸式自在継手によるトルク伝達は、前記ラジアル軸受１４を介して行うので、伝達可能なトルク（トルク容量）を確保する必要上、前記Ｌ範囲の長さ寸法は或る程度必要である。又、このＬ範囲で表された内輪軌道部分よりも基端寄り部分には、シールリング１５の基部２０を外嵌支持する。この支持力を十分に確保する為、及び、この嵌合部のシール性を確保する為には、前記軸部１２と前記基部２０との嵌合幅Ｗを、或る程度以上確保する必要がある。又、これら基部２０と軸部１２とを嵌合させた状態で、この基部２０に包埋した芯金１６の円輪部１８の片面を、前記十字軸９を構成する、前記結合基部１３の外面である段差面３８に当接させて、前記軸部１２の軸方向に関する、前記シールリング１５の位置決めを図る。この位置決めの精度を確保する為には、前記円輪部１８の片面と前記段差面３８との当接状態を安定させる必要上、これら両面同士を均一に当接させる必要がある。   Of the shaft portion 12 constituting the cross shaft 9, the L range portion in FIG. 11, which is an axial middle portion to a tip portion, serves as the inner ring raceway of the radial bearing 14 (see FIGS. 8 to 10). Grinding such as super finishing. Since the torque transmission by the cross shaft type universal joint is performed through the radial bearing 14, it is necessary to secure a transmittable torque (torque capacity), and a certain length dimension in the L range. Further, the base portion 20 of the seal ring 15 is externally supported so as to be closer to the base end than the inner ring raceway portion represented by the L range. In order to sufficiently secure the supporting force and to ensure the sealing performance of the fitting portion, it is necessary to secure the fitting width W between the shaft portion 12 and the base portion 20 to some extent. is there. Further, in a state where the base portion 20 and the shaft portion 12 are fitted to each other, one side of the annular portion 18 of the cored bar 16 embedded in the base portion 20 is formed on the joint base portion 13 constituting the cross shaft 9. The seal ring 15 is positioned with respect to the axial direction of the shaft portion 12 by being brought into contact with the step surface 38 which is an outer surface. In order to ensure the positioning accuracy, it is necessary to stabilize the contact state between one surface of the annular portion 18 and the stepped surface 38, and to make these both surfaces contact uniformly.

以上の事を考慮し、しかも、前記十字軸９の全長を少しでも短く抑えて、この十字軸９を組み込んだ自在継手３（図７〜１０参照）の小型・軽量化を図る為に従来は、図１１に示す様に、前記軸部１２の外周面と前記段差面３８とを連続させる凹曲面２８の曲率半径を小さくしていた。一方、前記自在継手３によりトルクを伝達する際に、前記軸部１２と前記結合基部１３との連続部には、この結合基部１３に対しこの軸部１２を倒す方向のモーメントが、繰り返し加わる。そして、このモーメントにより、前記凹曲面２８部分に応力が加わる。この応力の大きさは、この凹曲面２８の断面形状の曲率半径が小さい程、又、前記軸部１２の外径が小さい程、それぞれ大きくなる。従って、前記凹曲面２８部分に亀裂等の損傷が発生するのを防止すべく、この凹曲面２８部分に加わる応力を低く抑える為には、前記凹曲面２８の断面形状の曲率半径を大きくするか、又は、前記軸部１２の外径を大きくする必要があり、自在継手３の小型・軽量化を図る面からは不利になる。   In view of the above, in order to reduce the overall length of the cross shaft 9 as much as possible and to reduce the size and weight of the universal joint 3 (see FIGS. 7 to 10) incorporating the cross shaft 9, As shown in FIG. 11, the radius of curvature of the concave curved surface 28 that connects the outer peripheral surface of the shaft portion 12 and the stepped surface 38 is made small. On the other hand, when torque is transmitted by the universal joint 3, a moment in the direction of tilting the shaft portion 12 with respect to the coupling base portion 13 is repeatedly applied to the continuous portion of the shaft portion 12 and the coupling base portion 13. Then, stress is applied to the concave curved surface portion 28 by this moment. The magnitude of the stress increases as the radius of curvature of the cross-sectional shape of the concave curved surface 28 decreases and as the outer diameter of the shaft portion 12 decreases. Therefore, in order to suppress the stress applied to the concave curved surface 28 in order to prevent the concave curved surface 28 from being damaged such as cracks, the radius of curvature of the sectional shape of the concave curved surface 28 is increased. Alternatively, it is necessary to increase the outer diameter of the shaft portion 12, which is disadvantageous in terms of reducing the size and weight of the universal joint 3.

特許文献２には、十字軸の軸部の全長を確保して、この軸部がヨークの円孔から抜け出難くする為、この軸部の先端部に面取り部を設ける発明が記載されている。この様な特許文献２に記載された発明の構造によれば、大きなトルク伝達時に於ける、十字軸とヨークとの分離防止を図るべく、この十字軸を構成する各軸部の全長を長くした場合でも、この十字軸をヨークに組み込む事ができる。但し、前記特許文献２に記載された発明の構造にしても、前記図１１により説明した様な理由で、大きな負荷が加わった場合に於ける破壊強度（大負荷時破壊強度）を大きくし難く、信頼性及び耐久性の確保と、小型・軽量化との両立を図り難い。   Patent Document 2 describes an invention in which a chamfered portion is provided at the tip of the shaft portion in order to secure the full length of the shaft portion of the cross shaft and make it difficult for the shaft portion to come out of the circular hole of the yoke. According to the structure of the invention described in Patent Document 2 as described above, in order to prevent the cross shaft and the yoke from being separated when transmitting a large torque, the total length of each shaft portion constituting the cross shaft is increased. Even in this case, this cross shaft can be incorporated into the yoke. However, even with the structure of the invention described in Patent Document 2, it is difficult to increase the breaking strength (breaking strength under a large load) when a large load is applied for the reason described with reference to FIG. Therefore, it is difficult to achieve both reliability and durability while reducing size and weight.

特開２０１０−１８１０１６号公報JP 2010-181016 A 特開平１１−０３７１７１号公報JP 11-037171 A

本発明は、上述の様な事情に鑑みて、大負荷時破壊強度を大きくして、信頼性及び耐久性の確保と、小型・軽量化との両立を図り易い構造を実現すべく発明したものである。   In view of the circumstances as described above, the present invention was invented to increase the breaking strength under heavy load, and to realize a structure that facilitates both ensuring reliability and durability, and reducing size and weight. It is.

本発明の十字軸式自在継手は何れも、１対のヨークと、４個の円孔と、４個の軸受カップと、十字軸と、４組のラジアル軸受とを備える。
このうちの１対のヨークは、それぞれが二股状に形成されている。
又、前記各円孔は、これら両ヨークの両端部に、互いに同心に形成されている。
又、前記各軸受カップは、それぞれが有底円筒状で、互いの開口を対向させた状態で、前記各円孔の内側に内嵌固定されている。
又、前記十字軸は、結合基部の外周面に４本の軸部を放射状に固設して成る。そして、これら各軸部を前記各軸受カップ内に挿入した状態で、前記両ヨークと組み合わされている。
更に、前記各ラジアル軸受は、前記各軸部の外周面と前記各軸受カップの内周面との間に設けられている。 Each of the cross shaft type universal joints of the present invention includes a pair of yokes, four circular holes, four bearing cups, a cross shaft, and four sets of radial bearings.
Each of the pair of yokes is formed in a bifurcated shape.
The circular holes are concentrically formed at both ends of the yokes.
Each bearing cup has a bottomed cylindrical shape and is fitted and fixed inside each of the circular holes with the openings facing each other.
The cross shaft is formed by radially fixing four shaft portions on the outer peripheral surface of the coupling base portion. The shafts are combined with the yokes in a state where the shafts are inserted into the bearing cups.
Furthermore, each said radial bearing is provided between the outer peripheral surface of each said axial part, and the inner peripheral surface of each said bearing cup.

特に、本発明の十字軸式自在継手に於いては、前記十字軸を構成する前記各軸部の基端部外周面と前記結合基部の外面である段差面とを、それぞれ断面形状が部分円弧形である凹曲面により連続させている。又、これら各凹曲面のうちの少なくとも一部を、前記段差面のうちでこれら各凹曲面の周囲部分よりも、前記各軸部の軸方向に関して、この結合基部の中心寄りに存在させている。そして、前記段差面のうちで前記各軸部の基端部の周囲部分に、それぞれ環状凹部を形成している。   In particular, in the cross shaft type universal joint of the present invention, the cross-sectional shape of each of the base end portion outer peripheral surface of each shaft portion constituting the cross shaft and the step surface which is the outer surface of the coupling base portion is a partial circle. It is made continuous by an arc-shaped concave curved surface. Further, at least a part of each of the concave curved surfaces is present closer to the center of the coupling base in the axial direction of each of the shaft portions than the peripheral portion of each concave curved surface of the stepped surface. . And the annular recessed part is each formed in the surrounding part of the base end part of each said axial part among the said level | step difference surfaces.

又、本発明を実施する場合、前記十字軸を構成する前記各軸部と前記各軸受カップとを、これら各軸部の軸方向に関する相対変位を実質的に抑えた状態で（構成部材の弾性変形に基づく僅かな相対変位を除き阻止した状態で）組み合わせる。又、４個のシールリングを、前記各軸部の基端部にそれぞれの基部を外嵌支持した状態で、これら各軸部の基端部と前記各軸受カップの開口部との間に設ける。前記各シールリングは、金属製で円環状の芯金と、この芯金を包埋する事でこの芯金により補強された基部及びこの基部から延出したシールリップを備えた弾性材とから構成する。そして、前記各シールリングを、前記基部を前記各軸部の基端部に締り嵌めで外嵌支持すると共に、前記各シールリップを前記各軸受カップの外面に全周に亙って当接させた状態で、前記十字軸と前記両ヨークとの間に組み付ける。 Further, when the present invention is carried out, the shaft portions constituting the cross shaft and the bearing cups are substantially restrained from relative displacement in the axial direction of the shaft portions (elasticity of the constituent members). deforming a slight relative displacement based on the exception in blocking state) combined. Also, four seal rings are provided between the base end portions of the shaft portions and the opening portions of the bearing cups in a state where the base portions are fitted and supported on the base end portions of the shaft portions. . Each of the seal rings is composed of a metal-made annular cored bar, a base part reinforced by embedding the cored bar, and an elastic material having a seal lip extending from the base part. To do. Then, each seal ring is externally supported by an interference fit to the base end portion of each shaft portion, and each seal lip is brought into contact with the outer surface of each bearing cup over the entire circumference. In this state, it is assembled between the cross shaft and the yokes.

特に請求項１に記載した発明の場合には、前記各環状凹部の開口を前記各シールリングの基部の軸方向端面により塞いだ環状空間内に、グリースを封入する。Particularly, in the case of the invention described in claim 1, grease is sealed in an annular space in which the opening of each annular recess is closed by the axial end surface of the base portion of each seal ring.

これに対し、請求項２に記載した発明の場合には、前記各凹曲面を、断面形状の曲率半径が互いに異なる複数の曲面同士を滑らかに連続させた複合曲面とする。そして、これら各複合曲面を構成するそれぞれ複数の曲面のうち、前記各軸部に連続する内径側曲面の曲率半径を、これら各内径側曲面の周囲に存在する外径側曲面の曲率半径よりも大きくする。又、前記芯金を、円輪部と、この円輪部の内周縁側から前記各軸部の先端側に向けて折れ曲がった円筒部とから成る断面Ｌ字形とする。そして、前記円輪部のうちの少なくとも外径寄り部分を、前記十字軸の結合基部の外面である段差面に当接させる。 On the other hand, in the case of the invention described in claim 2, each concave curved surface is a complex curved surface in which a plurality of curved surfaces having different curvature radii in cross-sectional shape are smoothly continued. And among each of the plurality of curved surfaces constituting each composite curved surface, the radius of curvature of the inner diameter side curved surface continuing to each of the shaft portions is larger than the curvature radius of the outer diameter side curved surface existing around each of the inner diameter side curved surfaces. Enlarge. The cored bar has an L-shaped cross section including an annular portion and a cylindrical portion bent from the inner peripheral edge side of the annular portion toward the tip side of each shaft portion. Then, at least a portion near the outer diameter of the circular ring portion is brought into contact with a step surface which is an outer surface of the coupling base portion of the cross shaft.

又、請求項３に記載した発明の場合には、前記各シールリングを構成する弾性材の一部で、前記各基部の軸方向端面の内径寄り部分に、前記十字軸の結合基部の側に突出する凸部を設ける。そして、これら各凸部を前記各環状凹部内に進入させる。 In the case of the invention described in claim 3, a part of the elastic material constituting each of the seal rings is located near the inner diameter portion of the axial end face of each of the base portions, on the side of the coupling base portion of the cross shaft. Protruding protrusions are provided. And these each convex part is made to approach in said each annular recessed part.

又、請求項４に記載した発明の場合には、前記シールリングを構成する弾性材の基部の一部で、前記芯金よりも径方向外側部分に、前記十字軸の結合基部の側に突出する第二シールリップを全周に亙って形成する。そして、これら各第二シールリップの先端縁を、前記段差面のうちで前記環状凹部の周囲部分に、全周に亙って当接させる。 In the case of the invention described in claim 4, a part of the base portion of the elastic material constituting the seal ring protrudes radially outward from the cored bar and protrudes toward the coupling base portion of the cross shaft. The second seal lip is formed over the entire circumference. The leading edge of each of the second seal lips is brought into contact with the peripheral portion of the annular recess in the step surface over the entire circumference.

上述の様な請求項１〜４に記載した発明を実施する場合に好ましくは、例えば請求項５に記載した発明の様に、前記段差面のうちで前記環状凹部の周囲部分と、前記芯金を構成する円輪部のうちでこの周囲部分と当接する部分の軸方向片側面とを、平坦面若しくは部分円すい面状の傾斜面とする。そして、前記周囲部分とこの軸方向片側面とを面同士で当接させる。Preferably, when carrying out the invention described in claims 1 to 4 as described above, for example, as in the invention described in claim 5, the peripheral portion of the annular recess and the cored bar in the step surface. The one axial side surface of the portion that contacts the peripheral portion of the annular portion constituting the flat surface is defined as a flat surface or a partially conical inclined surface. And the said surrounding part and this axial direction one side surface are contact | abutted by surfaces.

又、請求項６に記載した本発明の場合には、前記十字軸を構成する前記各軸部と前記各軸受カップとを、これら各軸部の軸方向に関する相対変位を可能に組み合わせる。そして、これら各軸部に、弾性材製のシールリングを外嵌し、これら各シールリングを、前記各軸受カップの開口部側端面と、前記十字軸の段差面との間で、軸方向に関して弾性的に圧縮した状態で挟持する。
更に、前記各凹曲面を、断面形状の曲率半径が互いに異なる複数の曲面同士を滑らかに連続させた複合曲面とする。そして、これら各複合曲面を構成するそれぞれ複数の曲面のうち、前記各軸部に連続する内径側曲面の曲率半径を、これら各内径側曲面の周囲に存在する外径側曲面の曲率半径よりも大きくする。 In the case of the present invention described in claim 6, the shaft portions constituting the cross shaft and the bearing cups are combined so as to allow relative displacement in the axial direction of the shaft portions. Then, a seal ring made of an elastic material is externally fitted to each of these shaft portions, and each of these seal rings is between the opening side end surface of each bearing cup and the step surface of the cross shaft with respect to the axial direction. It is clamped in an elastically compressed state.
Further, each concave curved surface is a composite curved surface in which a plurality of curved surfaces having different cross-sectional radii of curvature are smoothly connected. And among each of the plurality of curved surfaces constituting each composite curved surface, the radius of curvature of the inner diameter side curved surface continuing to each of the shaft portions is larger than the curvature radius of the outer diameter side curved surface existing around each of the inner diameter side curved surfaces. Enlarge.

上述の様に構成する本発明の十字軸式自在継手によれば、大負荷時破壊強度を大きくして、信頼性及び耐久性の確保と、小型・軽量化との両立を図り易い構造を実現できる。
即ち、本発明の十字軸式自在継手の場合には、十字軸を構成する結合基部の外面である段差面のうちで各軸部の基端部の周囲部分にそれぞれ環状凹部を形成し、この環状凹部を利用して、これら各軸部の基端部外周面と段差面とを、それぞれ断面形状が部分円弧形である凹曲面により連続させている。従って、前記各軸部の軸方向中間部乃至先端部に存在する内輪軌道の軸方向長さ、及び、シールリングを装着可能な部分の軸方向幅を確保し、しかも、前記凹曲面の断面形状の曲率半径を大きくできる。この為、トルク伝達時に前記各軸部に加わる、倒れ方向のモーメントに拘らず、これら各軸部の基端部外周面と段差面との連続部に発生する応力を低く抑えられる。この結果、前記各軸部の長さ寸法や外径を特に大きくしなくても、前記連続部に亀裂等の損傷を発生し難くできて（大負荷時破壊強度を大きくして）、前記十字軸を組み込んだ十字軸式自在継手の信頼性及び耐久性を確保できる。言い換えれば、必要とする信頼性及び耐久性を同じとした場合には、前記十字軸の寸法を小さく抑えて、この十字軸を組み込んだ、十字軸式自在継手の小型・軽量化を図れる。 According to the cross joint universal joint of the present invention configured as described above, the structure is easy to achieve both high reliability and durability while reducing the size and weight by increasing the breaking strength under heavy load. it can.
That is, in the case of the cruciform universal joint of the present invention, an annular recess is formed in the peripheral portion of the base end portion of each shaft portion in the step surface which is the outer surface of the coupling base portion constituting the cruciform shaft. Utilizing the annular recess, the outer peripheral surface of the base end portion and the step surface of each shaft portion are made continuous by a concave curved surface having a partial arc shape in cross section. Accordingly, the axial length of the inner ring raceway existing in the axially intermediate portion or the tip portion of each shaft portion and the axial width of the portion where the seal ring can be mounted are secured, and the cross-sectional shape of the concave curved surface is ensured. Can increase the radius of curvature. For this reason, irrespective of the moment in the tilting direction applied to each shaft portion during torque transmission, the stress generated at the continuous portion between the base end portion outer peripheral surface and the step surface of each shaft portion can be kept low. As a result, even if the length and outer diameter of each shaft portion are not particularly increased, it is difficult to cause damage such as cracks in the continuous portion (increasing the breaking strength under heavy load), and the cross The reliability and durability of the cross joint universal joint incorporating the shaft can be secured. In other words, when the required reliability and durability are the same, the size of the cross shaft can be kept small, and the cross shaft universal joint incorporating the cross shaft can be reduced in size and weight.

本発明に関する参考例を、十字軸及びシールリングを取り出した状態で示す部分断面図。The fragmentary sectional view which shows the reference example regarding this invention in the state which took out the cross shaft and the seal ring. 本発明の実施の形態の第１例を示す、図１と同様の図（Ａ）と、環状凹部の断面形状の別例を示す部分断面図（Ｂ）。 The figure (A) similar to FIG. 1 which shows the 1st example of embodiment of this invention, and the fragmentary sectional view (B) which show another example of the cross-sectional shape of an annular recessed part. 同第２例を示す、図１と同様の図。The figure similar to FIG. 1 which shows the 2nd example . 同第３例を示す、図１と同様の図。The figure similar to FIG. 1 which shows the 3rd example . 同第４例を示す、図１と同様の図（Ａ）及び第二シールリップの形状の別例を示す部分断面図（Ｂ）。The same figure (A) which shows the 4th example , and a partial sectional view (B) which shows another example of the shape of the 2nd seal lip. 同第５例を示す、図１と同様の図（Ａ）及びシールリングの別例を示す部分断面図（Ｂ）。The same figure (A) as FIG. 1 which shows the 5th example , and the fragmentary sectional view (B) which shows another example of a seal ring. 自在継手を組み込んだステアリング装置の１例を示す斜視図。The perspective view which shows an example of the steering device incorporating a universal joint. 従来から知られている自在継手の第１例を示す、部分切断側面図。The partial cut side view which shows the 1st example of the universal joint known conventionally. 一部を省略して示す、図８の拡大Ｘ−Ｘ断面図。FIG. 9 is an enlarged XX cross-sectional view of FIG. 従来から知られている自在継手の第２例を示す、図９のＹ−Ｙ断面に相当する図。The figure equivalent to the YY cross section of FIG. 9 which shows the 2nd example of the universal joint known conventionally. 従来構造の場合に生じる問題を説明する為の、図１と同様の図。The same figure as FIG. 1 for demonstrating the problem which arises in the case of a conventional structure.

［参考例］
図１は、本発明に関する参考例を示している。尚、本参考例の特徴は、十字軸を構成する各軸部の基端部外周面と結合基部の外面である段差面との連続部の形状を工夫する事により、前記十字軸の寸法を大きくせずに、前記各軸部に加わるモーメントに基づいて前記連続部に発生する応力を低く抑えられる構造を実現する点にある。その他の部分の構造及び作用は、前述の図１０〜１１に示した従来構造の第２〜３例とほぼ同様であるから、同等部分に関する図示並びに説明は、省略若しくは簡略にし、以下、本参考例の特徴部分を中心に説明する。 [ Reference example ]
FIG. 1 shows a reference example related to the present invention . The feature of this reference example is that the dimensions of the cross shaft are determined by devising the shape of the continuous portion between the outer peripheral surface of the base end portion of each shaft portion constituting the cross shaft and the stepped surface which is the outer surface of the coupling base portion. The present invention is to realize a structure that can suppress the stress generated in the continuous portion based on the moment applied to each shaft portion without increasing the size. The construction and function of other portions are substantially the same as the first two or three example of the conventional structure shown in FIG. 10-11 described above, the illustration and description of the same portion was omitted or simplified, less, this reference The description will focus on the features of the example .

本参考例の場合には、十字軸式の自在継手を構成する十字軸９ａを構成する各軸部１２の基端部外周面と、結合基部１３の外面の一部で、これら各軸部１２の基端部の周囲部分である段差面３８とを、それぞれ断面形状が部分円弧形である凹曲面２８ａにより連続させている。又、これら各凹曲面２８ａのうちの一部を、前記段差面３８のうちでこれら各凹曲面２８ａの周囲部分よりも、前記各軸部１２の軸方向に関して、前記結合基部１３の中心寄り（図１の左寄り）に存在させている。そして、前記段差面３８のうちで前記各軸部１２の基端部の周囲部分に、それぞれ環状凹部２９を形成している。前記各凹曲面２８ａの内外両周縁部のうち、内周縁は、前記各軸部１２と滑らかに連続している。言い換えれば、これら各軸部１２の母線は、前記各凹曲面２８ａの内周縁の接線方向に存在する。一方、前記段差面３８とこれら各凹曲面２８ａの外周縁側との連続部の断面形状は、微分不能な（単一の接線を描けない）、少しだけ尖った形状としている。 In the case of this reference example, the shaft portion 12 is formed on the outer peripheral surface of the base end portion of each shaft portion 12 and the outer surface of the coupling base portion 13 constituting the cross shaft 9a constituting the cross shaft type universal joint. And a stepped surface 38 which is a peripheral portion of the base end portion thereof is made continuous by a concave curved surface 28a having a partial arc shape in cross section. Further, a part of each of the concave curved surfaces 28a is located closer to the center of the coupling base 13 in the axial direction of each of the shaft portions 12 than the peripheral portion of each of the concave curved surfaces 28a in the stepped surface 38 ( It exists on the left side of FIG. Then, annular recesses 29 are respectively formed in the stepped surface 38 around the base end portion of each shaft portion 12. Of the inner and outer peripheral edge portions of each concave curved surface 28a, the inner peripheral edge is smoothly continuous with each axial portion 12. In other words, the generatrix of each shaft portion 12 exists in the tangential direction of the inner peripheral edge of each concave curved surface 28a. On the other hand, the cross-sectional shape of the continuous portion between the step surface 38 and the outer peripheral edge side of each concave curved surface 28a is a slightly pointed shape that cannot be differentiated (cannot draw a single tangent).

又、前記各軸部１２の基端部に、芯金１６と弾性材１７ａとから成るシールリング１５ａを外嵌支持している。このシールリング１５ａの構成は、ラジアルシールリップ２１ａの先端部が二股になっている点以外、前述の図９〜１０に示した従来構造とほぼ同様である。前記シールリング１５ａは、前記弾性材１７ａの基部２０を前記各軸部１２の基端部に締り嵌めで外嵌すると共に、前記芯金１６の円輪部１８の軸方向片側面（図１の左側面）の外径寄り部分を、前記段差面３８のうちで前記環状凹部２９の周囲部分に突き当てた状態で、前記各軸部１２の基端部に組み付けている。この状態で、前記円輪部１８の軸方向片側面と前記段差面３８のうちで前記環状凹部２９の周囲部分とが、面同士で当接する。尚、この段差面３８のうちでこの環状凹部２９の周囲部分と、前記円輪部１８の軸方向片側面とは、前記各軸部１２の中心軸に対し直交する方向に存在する平坦面とする事が、各部の加工を容易にする面からは好ましい。但し、当接状態を安定させる為に、前記段差面３８のうちでこの環状凹部２９の周囲部分と前記円輪部１８の軸方向片側面とのうちの一方を部分円すい状の凸面とし、他方を同じ角度だけ傾斜した部分円すい状の凹面とする事もできる。何れの場合でも、十字軸式の自在継手を組み立てた状態では、前記弾性材１７ａのラジアルシールリップ２１ａの先端縁が軸受カップ１１ａの端部外周面に、同じくスラストシールリップ２２が内向鍔部２３の外面に、それぞれ全周に亙って弾性的に当接する。   A seal ring 15a composed of a core metal 16 and an elastic material 17a is externally supported on the base end portion of each shaft portion 12. The structure of the seal ring 15a is substantially the same as the conventional structure shown in FIGS. 9 to 10 except that the tip of the radial seal lip 21a is bifurcated. The seal ring 15a externally fits the base portion 20 of the elastic member 17a to the base end portion of each shaft portion 12 by an interference fit, and one axial side surface of the annular portion 18 of the core metal 16 (see FIG. 1). A portion closer to the outer diameter of the left side surface is assembled to the base end portion of each shaft portion 12 in a state where it abuts against the peripheral portion of the annular recess 29 in the step surface 38. In this state, one side surface in the axial direction of the annular ring portion 18 and the peripheral portion of the annular recess 29 in the step surface 38 abut each other. Of the step surface 38, the peripheral portion of the annular recess 29 and the one axial side surface of the annular portion 18 are flat surfaces existing in a direction perpendicular to the central axis of each shaft portion 12. It is preferable from the viewpoint of facilitating the processing of each part. However, in order to stabilize the contact state, one of the stepped surface 38 and the peripheral portion of the annular recess 29 and one axial side surface of the annular portion 18 is a partially conical convex surface, and the other Can be a conical concave surface inclined by the same angle. In any case, in a state where the cross shaft type universal joint is assembled, the end edge of the radial seal lip 21a of the elastic member 17a is on the outer peripheral surface of the end portion of the bearing cup 11a, and the thrust seal lip 22 is also the inward flange portion 23. Are elastically contacted with the outer surface of each of the outer circumferences over the entire circumference.

前記自在継手の伝達効率を良好にすると共に、前記各シールリング１５ａによるシール性能を確保する為には、前記各シールリップ２１ａ、２２の弾性変形量を適正に規制する必要がある。そして、この為には、前記各シールリング１５ａと前記各軸受カップ１１ａとの位置関係を適正に規制する必要がある。このうちの各シールリング１５ａの軸方向位置は、前記円輪部１８の軸方向片側面と前記段差面３８との当接により、適正に規制できる。又、前記各軸受カップ１１ａの軸方向位置は、ヨーク８ａの円孔１０（図１０参照）に対する嵌合位置を調節し、座部２６ａの内面中央部と前記軸部１２の端面中央部とを当接させる事により規制できる。この為、本参考例の構造によれば、前記各シールリップ２１ａ、２２の弾性変形量を適正に規制して、前記自在継手の伝達効率を良好にすると共に、前記各シールリング１５ａによるシール性能を確保できる。 In order to improve the transmission efficiency of the universal joint and to ensure the sealing performance by the seal rings 15a, it is necessary to properly regulate the elastic deformation amounts of the seal lips 21a and 22. For this purpose, it is necessary to properly regulate the positional relationship between the seal rings 15a and the bearing cups 11a. Of these, the axial position of each seal ring 15 a can be properly regulated by the contact between the one axial side surface of the annular ring portion 18 and the stepped surface 38. Further, the axial position of each bearing cup 11a adjusts the fitting position of the yoke 8a with respect to the circular hole 10 (see FIG. 10) so that the inner surface central portion of the seat portion 26a and the end surface central portion of the shaft portion 12 are connected. It can be regulated by bringing it into contact. For this reason, according to the structure of the present reference example , the elastic deformation amount of each of the seal lips 21a, 22 is appropriately regulated to improve the transmission efficiency of the universal joint, and the sealing performance by the seal ring 15a. Can be secured.

更に、前記各環状凹部２９の存在により、前記各軸部１２の軸方向寸法を大きくしなくても、これら各軸部１２の基端部外周面と前記段差面３８との連続部に存在する凹曲面部２８ａの断面形状の曲率半径を大きくできる。この為、前記自在継手によるトルク伝達時に、前記各軸部１２に加わる、倒れ方向のモーメントに拘らず、これら各軸部１２の基端部外周面と前記段差面３８との連続部に発生する応力を低く抑えられる。この結果、前記各軸部１２の長さ寸法や外径を特に大きくしなくても、大負荷時破壊強度を大きくして、前記連続部に亀裂等の損傷を発生し難くできて、前記十字軸９ａを組み込んだ十字軸式自在継手の信頼性及び耐久性を確保できる。逆に、必要とする大負荷時破壊強度、延いては信頼性及び耐久性を同じとした場合には、前記十字軸９ａの寸法を小さく抑えて、この十字軸９ａを組み込んだ、十字軸式自在継手の小型・軽量化を図れる。何れにしても、前記凹曲面部２８ａの断面形状の曲率半径を大きくする為に、前記各軸部１２の軸方向中間部乃至先端部に存在するラジアル軸受１４の為の内輪軌道の軸方向長さ、及び、前記各シールリング１５ａを構成する弾性材１７ａの基部２０を外嵌する部分の軸方向幅を確保できる。従って、前記十字軸式自在継手のトルク容量を確保すると共に、前記各シールリング１５ａの位置決め性（姿勢の安定化）も図れる。   Further, due to the presence of the annular recesses 29, the axial end dimensions of the shaft portions 12 do not have to be increased, and the base end portion outer peripheral surface of each shaft portion 12 and the stepped surface 38 are present. The radius of curvature of the cross-sectional shape of the concave curved surface portion 28a can be increased. For this reason, at the time of torque transmission by the universal joint, regardless of the moment in the falling direction applied to each shaft portion 12, it occurs in the continuous portion between the outer peripheral surface of the base end portion of each shaft portion 12 and the step surface 38. Stress can be kept low. As a result, even if the length and outer diameter of each of the shaft portions 12 are not particularly increased, the breaking strength under a large load can be increased and damage such as cracks can hardly occur in the continuous portion. The reliability and durability of the cross shaft type universal joint incorporating the shaft 9a can be ensured. On the other hand, if the required breaking strength at the time of heavy load, and the reliability and durability are the same, the cross shaft 9a is incorporated with the cross shaft 9a being kept small. The universal joint can be reduced in size and weight. In any case, in order to increase the radius of curvature of the cross-sectional shape of the concave curved surface portion 28a, the axial length of the inner ring raceway for the radial bearing 14 existing at the axial intermediate portion or tip portion of each shaft portion 12 is determined. And the axial direction width | variety of the part which externally fits the base 20 of the elastic material 17a which comprises each said seal ring 15a is securable. Accordingly, the torque capacity of the cross shaft type universal joint can be ensured, and the positioning performance (posture stabilization) of each seal ring 15a can be achieved.

［実施の形態の第１例］
図２は、本発明の実施の形態の第１例を示している。本例の場合には、十字軸９ｂを構成する段差面３８のうちで、各軸部１２の基端部を囲む部分に形成した各凹曲面２８ｂの断面形状を、曲率半径が互いに異なる複数の曲面同士を滑らかに連続させた複合曲面としている。そして、これら各複合曲面を構成するそれぞれ複数の曲面のうち、前記各軸部１２に連続する内径側曲面３０の曲率半径を、これら各内径側曲面３０の周囲に存在する外径側曲面３１の曲率半径よりも大きくしている。これら内径側、外径側両曲面３０、３１のうち、内径側曲面３０に関する曲率半径は、上述した参考例の凹曲面２８ａ｛図２の（Ａ）の鎖線参照｝の曲率半径と同じとし、外径側曲面３１に関する曲率半径を、この凹曲面２８ａの曲率半径よりも十分に小さくしている。又、前記各内径側曲面３０の外周縁と前記各外径側曲面３１の内周縁とを、互いに接線方向で滑らかに連続させている。 [ First example of embodiment]
FIG. 2 shows a first example of the embodiment of the present invention . In the case of this example, among the stepped surfaces 38 constituting the cross shaft 9b, the cross-sectional shape of each concave curved surface 28b formed in the portion surrounding the base end portion of each shaft portion 12 is a plurality of different curvature radii. It is a compound curved surface in which curved surfaces are smoothly connected. Of the plurality of curved surfaces constituting each composite curved surface, the radius of curvature of the inner diameter side curved surface 30 continuing to each shaft portion 12 is set to the outer diameter side curved surface 31 around each inner diameter side curved surface 30. It is larger than the radius of curvature. Of these inner diameter side and outer diameter side curved surfaces 30, 31, the radius of curvature related to the inner diameter side curved surface 30 is the same as the curvature radius of the concave curved surface 28a of the reference example described above (see the chain line in FIG. 2A). The radius of curvature related to the outer diameter side curved surface 31 is made sufficiently smaller than the radius of curvature of the concave curved surface 28a. Further, the outer peripheral edge of each inner diameter side curved surface 30 and the inner peripheral edge of each outer diameter side curved surface 31 are smoothly and continuously connected to each other in the tangential direction.

上述の様に構成する本例の構造によれば、前記各軸部１２の基端部の断面形状の曲率半径を大きくし、十字軸式自在継手によるトルク伝達時にこの基端部に大きな応力が発生するのを防止しつつ、図２の（Ａ）に鎖線で示した参考例の構造に比べて、環状凹部２９ａの外径を小さくできる。そして、この外径を小さくできる分、シールリング１５ａを構成する芯金１６の円輪部１８の軸方向片側面と、前記段差面３８との接触面積を広くし、前記シールリング１５ａの姿勢をより安定させて、このシールリング１５ａによるシール性能の向上を図れる。 According to the structure of this example configured as described above, the curvature radius of the cross-sectional shape of the base end portion of each shaft portion 12 is increased, and a large stress is applied to the base end portion during torque transmission by the cross shaft universal joint. The outer diameter of the annular recess 29a can be reduced as compared with the structure of the reference example shown by the chain line in FIG. Then, the contact area between the one side surface in the axial direction of the annular portion 18 of the metal core 16 constituting the seal ring 15a and the stepped surface 38 is increased by the amount that the outer diameter can be reduced, and the posture of the seal ring 15a is increased. The sealing performance can be improved by the seal ring 15a in a more stable manner.

尚、本例の如く、前記各凹曲面２８ｂの断面形状を複合曲面とする場合に、この複合曲面を構成する曲面の種類は２種類に限らない。３種類以上であっても良いし、内周縁側から外周縁側に向けて曲率半径を連続的に変化させても良い。更には、図２の（Ｂ）に示す様に、環状凹部２９ｂの外径側端部を、各軸部１２の中心軸をその中心とする円筒面３２としても良い。
その他の部分の構成及び作用は、上述した参考例と同様であるから、同等部分に関する説明は省略する。 As in this example, when the cross-sectional shape of each concave curved surface 28b is a compound curved surface, the types of curved surfaces constituting the compound curved surface are not limited to two. There may be three or more types, and the curvature radius may be continuously changed from the inner peripheral edge side toward the outer peripheral edge side. Further, as shown in FIG. 2B, the outer diameter side end of the annular recess 29b may be a cylindrical surface 32 having the center axis of each shaft portion 12 as its center.
Since the configuration and operation of the other parts are the same as those of the reference example described above, the description of the equivalent parts is omitted.

［実施の形態の第２例］
図３は、本発明の実施の形態の第２例を示している。本例の場合も、十字軸９ａを構成する各軸部１２の基端部にシールリング１５ａの基部２０を、締り嵌めで外嵌支持している。そして、この基部２０により、段差面３８のうちで、前記各軸部１２の基端部を囲む部分に形成した各環状凹部２９の開口を塞いでいる。特に、本例の場合には、これら各環状凹部２９の開口を塞ぐ事で画成した環状空間３３内に、グリース３４を封入している。 [ Second Example of Embodiment]
FIG. 3 shows a second example of the embodiment of the present invention . Also in this example, the base portion 20 of the seal ring 15a is externally supported by an interference fit at the base end portion of each shaft portion 12 constituting the cross shaft 9a. The base 20 closes the openings of the annular recesses 29 formed in the stepped surface 38 in the portion surrounding the base end of the shaft 12. In particular, in the case of this example, the grease 34 is enclosed in an annular space 33 defined by closing the openings of the annular recesses 29.

この様な本例の構造によれば、前記基部２０の端面と前記段差面３８との突合せ部のシール性を向上させて、外部空間に存在する泥水等の異物が、この突合せ部を通じて、ラジアル軸受１４側に入り込む事を防止できる。尚、本例の様にグリースによりシール性を向上させる構造は、上述の図２に示した実施の形態の第１例の構造と組み合わせて実施する事もできる。
その他の部分の構成及び作用は、前述した参考例と同様であるから、同等部分に関する説明は省略する。 According to such a structure of this example, the sealing performance of the abutting portion between the end surface of the base portion 20 and the stepped surface 38 is improved, and foreign matters such as muddy water existing in the external space are radially passed through the abutting portion. It can prevent entering into the bearing 14 side. In addition, the structure which improves a sealing performance with grease like this example can also be implemented in combination with the structure of the first example of the embodiment shown in FIG. 2 described above.
Since the configuration and operation of the other parts are the same as those of the reference example described above, the description of the equivalent parts is omitted.

［実施の形態の第３例］
図４は、本発明の実施の形態の第３例を示している。本例の場合も、十字軸９ａを構成する各軸部１２の基端部にシールリング１５ｂの基部２０ａを、締り嵌めで外嵌支持している。特に、本例の場合には、これら各シールリング１５ｂを構成する弾性材１７ｂの一部で、前記各基部２０ａの軸方向端面の内径寄り部分に、十字軸９ａの結合基部１３の側に突出する凸部３５を、全周に亙って設けている。そして、これら各凸部３５を、前記十字軸９ａを構成する段差面３８のうちで、前記各軸部１２の基端部の周囲部分に形成した、各環状凹部２９内に進入させている。そして、前記基部２０ａによりこれら各環状凹部２９の開口を塞ぐ事で画成した環状空間３３の容積を、実質的に低減している。 [ Third example of embodiment]
FIG. 4 shows a third example of the embodiment of the present invention . Also in this example, the base portion 20a of the seal ring 15b is externally supported by an interference fit at the base end portion of each shaft portion 12 constituting the cross shaft 9a. In particular, in the case of this example, a part of the elastic material 17b constituting each of the seal rings 15b protrudes toward the coupling base 13 side of the cross shaft 9a at a portion closer to the inner diameter of the axial end surface of each base 20a. Convex portions 35 are provided over the entire circumference. These convex portions 35 are made to enter into the respective annular concave portions 29 formed in the peripheral portion of the base end portion of each shaft portion 12 in the step surface 38 constituting the cross shaft 9a. The volume of the annular space 33 defined by closing the openings of the annular recesses 29 by the base portion 20a is substantially reduced.

この様な本例の構造によれば、温度変化に基づく前記各環状空間３３内の圧力変化に伴って外部空間に存在する泥水等の異物が、前記各基部２０ａの端面と前記段差面３８との突合せ部を通じて、前記各環状空間３３内に入り込む事を抑えられる。即ち、これら各環状空間３３内に存在する空気の容積が多いと、温度変化（温度上昇後の低下）に伴ってこれら各環状空間３３内に外気が吸入され易くなる。そして、この外気と共に外部空間に浮遊する異物が、これら各環状空間３３を通じて各ラジアル軸受１４側に入り込むと、これら各ラジアル軸受１４の耐久性が損なわれる。これに対して本例の構造によれば、前記各凸部３５の分だけ、前記各環状隙間３３の容積を低減し、温度変化に伴う、これら各環状隙間３３内と前記外部空間との間での空気の出入りを少なく抑えて、これら各環状隙間３３を通じ、この外部空間に浮遊する異物（周囲に存在する水滴等を含む）が、前記各ラジアル軸受１４側に入り込む事を防止できる。尚、この様な機構による異物進入防止効果（シール性）を確保する為には、前記各凸部３５により、前記各環状空間３３全体を塞ぐ事が好ましい。この様な本例の構造に関しても、前述の図２に示した実施の形態の第１例の構造と組み合わせて実施する事もできる。
その他の部分の構成及び作用は、前述した参考例と同様であるから、同等部分に関する説明は省略する。 According to such a structure of this example, foreign matters such as muddy water existing in the external space due to the pressure change in each annular space 33 based on the temperature change are caused by the end face of each base portion 20a and the step surface 38. It is possible to suppress entry into the annular spaces 33 through the butting portions. That is, if the volume of air existing in each annular space 33 is large, outside air is easily sucked into each annular space 33 with a temperature change (decrease after the temperature rises). And if the foreign substance which floats in external space with this external air enters into each radial bearing 14 side through each said annular space 33, durability of these each radial bearing 14 will be impaired. On the other hand, according to the structure of this example, the volume of each annular gap 33 is reduced by the amount of each convex portion 35, and the space between the inside of each annular gap 33 and the external space accompanying a temperature change is reduced. It is possible to prevent foreign matters (including water droplets existing in the surroundings) from entering the respective radial bearings 14 through the annular gaps 33 while suppressing the entry / exit of air at the center. In order to secure the foreign matter entry preventing effect (sealability) by such a mechanism, it is preferable to block the entire annular spaces 33 with the convex portions 35. The structure of this example can also be implemented in combination with the structure of the first example of the embodiment shown in FIG.
Since the configuration and operation of the other parts are the same as those of the reference example described above, the description of the equivalent parts is omitted.

［実施の形態の第４例］
図５は、本発明の実施の形態の第４例を示している。本例の場合には、各シールリング１５ｃを構成する弾性材１７ｃの基部２０ｂの一部で、芯金１６の円輪部１８の外周縁よりも径方向外側部分に、十字軸９ａの結合基部１３の側に突出する第二シールリップ３６を、それぞれ全周に亙って形成する。そして、これら各第二シールリップ３６の先端縁を、前記十字軸９ａを構成する段差面３８のうちで環状凹部２９の周囲部分に、全周に亙って当接させている。この様な、前記各第二シールリップ３６により、前記環状凹部２９の存在に拘らず、前記各シールリング１５ｃによるシール性能の確保を図っている。 [ Fourth Example of Embodiment]
FIG. 5 shows a fourth example of the embodiment of the present invention . In the case of this example, a part of the base portion 20b of the elastic member 17c constituting each seal ring 15c and a joint base portion of the cross shaft 9a on a radially outer side portion of the outer peripheral edge of the annular portion 18 of the cored bar 16 The second seal lips 36 projecting toward the side 13 are formed over the entire circumference. The leading edge of each second seal lip 36 is brought into contact with the peripheral portion of the annular recess 29 in the step surface 38 constituting the cross shaft 9a over the entire circumference. Such second seal lips 36 ensure the sealing performance of the seal rings 15c regardless of the presence of the annular recess 29.

尚、図５のうちの（Ａ）に示した構造の場合には、前記各第二シールリップ３６の方向を、先端縁に向かうに従って径方向外側に向かう方向に傾斜させている。そして、前記基部２０と前記環状凹部２９とにより画成された環状空間３３内に存在する余分なグリースや空気を、温度上昇時に外部空間に逃がすが、温度低下時にこの外部空間に浮遊する異物を前記環状空間内に吸い込み難くして、必要とするシール性の確保を図っている。但し、各第二シールリップの形状は、上述の様な形状に限定するものではない。例えば図５の（Ｂ）に示す様な形状の、第二シールリップ３６ａを採用する事もできる。尚、この図５の（Ｂ）に示した第二のシールリップ３６ａは、長さ寸法を大きくする事で、段差面３８との当接に基づく締め代の変化に追従し易く（撓み易く）している。要は、前記各シールリング１５ｃを、前記十字軸９ａを構成する各軸部１２の基端部に外嵌支持した状態で、前記各第二シールリップ３６、３６ａの先端縁が、前記段差面３８のうちで環状凹部２９の周囲部分に、全周に亙って弾性的に当接できる形状であれば良い。この様な本例の構造に関しても、前述の図２に示した実施の形態の第１例の構造と組み合わせて実施する事もできる。
その他の部分の構成及び作用は、前述した参考例と同様であるから、同等部分に関する説明は省略する。 In the case of the structure shown in FIG. 5A, the direction of each of the second seal lips 36 is inclined in the direction toward the radially outer side toward the tip edge. Then, excess grease and air existing in the annular space 33 defined by the base 20 and the annular recess 29 are released to the external space when the temperature rises. It is difficult to suck into the annular space to ensure the necessary sealing performance. However, the shape of each second seal lip is not limited to the shape as described above. For example, the second seal lip 36a having a shape as shown in FIG. Incidentally, the second seal lip 36a shown in FIG. 5B can easily follow the change of the tightening margin based on the contact with the step surface 38 (easily bent) by increasing the length dimension. doing. In short, in a state where the seal rings 15c are externally supported by the base end portions of the shaft portions 12 constituting the cross shaft 9a, the tip edges of the second seal lips 36, 36a Any shape can be used as long as it can elastically contact the peripheral portion of the annular recess 29 among the entire circumference. The structure of this example can also be implemented in combination with the structure of the first example of the embodiment shown in FIG.
Since the configuration and operation of the other parts are the same as those of the reference example described above, the description of the equivalent parts is omitted.

［実施の形態の第５例］
図６は、本発明の実施の形態の第５例を示している。先に述べた実施の形態の第１〜４例及び参考例の構造が何れも、シール性能の高いシールリングを組み込んで成り、車室外（エンジンルーム内）に設置するのに適切な構造であるのに対して、本例の構造は、車室内に設置するのに適切な構造である。この様な本例の十字軸式自在継手の場合には、十字軸９ａを構成する各軸部１２と各軸受カップ１１ｂとを、これら各軸部１２の軸方向に関する相対変位を可能に組み合わせている。そして、これら各軸部１２に、弾性材製のシールリングであるＯリング３７を外嵌し、これら各Ｏリング３７を、前記各軸受カップ１１ｂの開口部側端面である、この開口部に形成した内向鍔部２３の外側面と、前記十字軸９ａを構成する段差面３８との間に挟持している。十字軸式自在継手を組み立てた状態で前記Ｏリング３７は、この段差面３８と前記内向鍔部２３の外側面との間で、軸方向に関して弾性的に圧縮する。又、前記各軸部１２の先端部と前記各軸受カップ１１ｂの内面とは離隔したままとなる。前記十字軸式自在継手によるトルク伝達時に、これら各軸部１２の先端部と各軸受カップ１１ｂとの間に作用するスラスト荷重は、前記各Ｏリング３７が支承する。尚、これら各Ｏリング３７の断面形状は、図６の（Ａ）に示した様な円形に限らず、（Ｂ）に示した様な角形でも良い。又、本例の構造と、前記図２に示した、断面形状の曲率半径が互いに異なる複数の曲面同士を滑らかに連続させた複合曲面である、環状凹部２９ａ、２９ｂとを組み合わせて実施する事もできる。この様にすれば、前記段差面３８のうちで、前記Ｏリング３７を当接させられる部分の幅寸法を確保し易い。
その他の部分の構成及び作用は、前述した参考例と同様であるから、同等部分に関する説明は省略する。 [ Fifth Example of Embodiment]
FIG. 6 shows a fifth example of the embodiment of the present invention . Each of the structures of the first to fourth examples and the reference example of the embodiment described above is a structure that incorporates a seal ring with high sealing performance and is suitable for installation outside the vehicle compartment (inside the engine room). On the other hand, the structure of this example is a structure suitable for installation in the passenger compartment. In the case of such a cruciform universal joint of this example, the shaft portions 12 and the bearing cups 11b constituting the cruciform shaft 9a are combined so as to allow relative displacement in the axial direction of the shaft portions 12. Yes. Then, an O-ring 37 that is a seal ring made of an elastic material is externally fitted to each of the shaft portions 12, and each of the O-rings 37 is formed in this opening that is an opening side end surface of each of the bearing cups 11b. The outer surface of the inward flange 23 is sandwiched between the step surface 38 constituting the cross shaft 9a. The O-ring 37 is elastically compressed in the axial direction between the step surface 38 and the outer surface of the inward flange 23 in a state where the cross shaft universal joint is assembled. Moreover, the front-end | tip part of each said shaft part 12 and the inner surface of each said bearing cup 11b remain spaced apart. Each O-ring 37 supports the thrust load that acts between the tip of each shaft 12 and each bearing cup 11b during torque transmission by the cross shaft universal joint. The cross-sectional shape of each O-ring 37 is not limited to a circle as shown in FIG. 6A, but may be a square as shown in FIG. Further, the structure of this example is combined with the annular recesses 29a and 29b, which are complex curved surfaces in which a plurality of curved surfaces having different cross-sectional radii of curvature shown in FIG. You can also. In this way, it is easy to ensure the width dimension of the portion of the step surface 38 where the O-ring 37 is brought into contact.
Since the configuration and operation of the other parts are the same as those of the reference example described above, the description of the equivalent parts is omitted.

本発明の十字軸式自在継手は、ステアリング装置に限らず、各種トルク伝達機構に組み付けた状態で使用できる。   The cross shaft type universal joint of the present invention is not limited to a steering device, and can be used in a state assembled to various torque transmission mechanisms.

１ ステアリングホイール
２ ステアリングシャフト
３ 自在継手
４ 中間シャフト
５ ステアリングギヤユニット
６ 入力軸
７ タイロッド
８ａ、８ｂ ヨーク
９、９ａ、９ｂ 十字軸
１０ 円孔
１１、１１ａ、１１ｂ 軸受カップ
１２ 軸部
１３ 結合基部
１４ ラジアル軸受
１５、１５ａ、１５ｂ、１５ｃ シールリング
１６ 芯金
１７、１７ａ、１７ｂ、１７ｃ 弾性材
１８ 円輪部
１９ 円筒部
２０、２０ａ、２０ｂ 基部
２１、２１ａ ラジアルシールリップ
２２ スラストシールリップ
２３ 内向鍔部
２４ 挿入孔
２５ ピン
２６、２６ａ 底部
２７ 突条
２８、２８ａ、２８ｂ 凹曲面
２９、２９ａ、２９ｂ 環状凹部
３０ 内径側曲面
３１ 外径側曲面
３２ 円筒面
３３ 環状空間
３４ グリース
３５ 凸部
３６、３６ａ 第二シールリップ
３７ Ｏリング
３８ 段差面 DESCRIPTION OF SYMBOLS 1 Steering wheel 2 Steering shaft 3 Universal joint 4 Intermediate shaft 5 Steering gear unit 6 Input shaft 7 Tie rod 8a, 8b Yoke 9, 9a, 9b Cross shaft 10 Circular hole 11, 11a, 11b Bearing cup 12 Shaft part 13 Joint base part 14 Radial Bearing 15, 15a, 15b, 15c Seal ring 16 Core metal 17, 17a, 17b, 17c Elastic material 18 Annular portion 19 Cylindrical portion 20, 20a, 20b Base portion 21, 21a Radial seal lip 22 Thrust seal lip 23 Inward facing portion 24 Insertion hole 25 Pin 26, 26a Bottom 27 Projection 28, 28a, 28b Concave surface 29, 29a, 29b Annular recess 30 Inner surface curved surface 31 Outer surface side curved surface 32 Cylindrical surface 33 Annular space 34 Grease 35 Convex portion 36, 36a Second Seal lip 37 O Ring 38 Stepped surface

Claims (6)

それぞれが二股状に形成された１対のヨークと、
これら両ヨークの両端部に互いに同心に形成された４個の円孔と、
互いの開口を対向させた状態でこれら各円孔の内側に内嵌固定された、それぞれが有底円筒状である４個の軸受カップと、
結合基部の外周面に４本の軸部を放射状に固設して成り、これら各軸部をこれら各軸受カップ内に挿入した状態で前記両ヨークと組み合わされた十字軸と、
これら各軸部の外周面とこれら各軸受カップの内周面との間に設けられた４組のラジアル軸受と、
を備えた十字軸式自在継手に於いて、
前記十字軸を構成する前記各軸部の基端部外周面と前記結合基部の外面である段差面とを、それぞれ断面形状が部分円弧形である凹曲面により連続させており、これら各凹曲面のうちの少なくとも一部を、前記段差面のうちでこれら各凹曲面の周囲部分よりも、前記各軸部の軸方向に関し、この結合基部の中心寄りに存在させて、前記段差面のうちで前記各軸部の基端部の周囲部分にそれぞれ環状凹部を形成しており、
前記十字軸を構成する前記各軸部と前記各軸受カップとが、これら各軸部の軸方向に関する相対変位を実質的に抑えた状態で組み合わされており、
これら各軸部の基端部にそれぞれの基部を外嵌支持された状態で、これら各軸部の基端部と前記各軸受カップの開口部との間に４個のシールリングが設けられており、
これら各シールリングは、金属製で円環状の芯金と、この芯金を包埋する事でこの芯金により補強された基部及びこの基部から延出したシールリップを備えた弾性材とから成るものであり、
前記各シールリングは、前記基部を前記各軸部の基端部に締り嵌めで外嵌支持すると共に、前記各シールリップを前記各軸受カップの外面に全周に亙って当接させた状態で、前記十字軸と前記両ヨークとの間に組み付けられており、
前記各環状凹部の開口を前記各シールリングの基部の軸方向端面により塞いだ環状空間内に、グリースが封入されている、
事を特徴とする十字軸式自在継手。 A pair of yokes each formed in a bifurcated shape;
Four circular holes formed concentrically with each other at both ends of these yokes,
Four bearing cups each having a bottomed cylindrical shape, fitted and fixed inside each of these circular holes with their openings facing each other;
A cross shaft combined with the yokes in a state in which the four shaft portions are radially fixed to the outer peripheral surface of the coupling base portion, and the shaft portions are inserted into the bearing cups;
4 sets of radial bearings provided between the outer peripheral surface of each shaft part and the inner peripheral surface of each bearing cup ;
In the cross joint universal joint with
The outer peripheral surface of the base end portion of each shaft portion constituting the cross shaft and the step surface which is the outer surface of the coupling base portion are continuously connected by a concave curved surface having a partial arc shape in cross section. At least a part of the curved surface is located closer to the center of the coupling base with respect to the axial direction of each of the shaft portions than the surrounding portion of each concave curved surface of the step surfaces, And forming an annular recess in the peripheral portion of the base end portion of each shaft portion ,
The shaft portions constituting the cross shaft and the bearing cups are combined in a state where the relative displacement in the axial direction of the shaft portions is substantially suppressed,
Four seal rings are provided between the base end portions of the shaft portions and the opening portions of the bearing cups with the base portions fitted and supported on the base end portions of the shaft portions. And
Each of these seal rings is made of a metal and annular cored bar, and a base part reinforced by embedding the cored bar and an elastic material having a seal lip extending from the base part. Is,
Each seal ring is a state in which the base is externally supported by an interference fit to the base end of each shaft portion, and each seal lip is in contact with the outer surface of each bearing cup over the entire circumference. And is assembled between the cross shaft and the yokes,
Grease is sealed in an annular space in which the opening of each annular recess is closed by the axial end surface of the base of each seal ring.
A cross joint universal joint characterized by それぞれが二股状に形成された１対のヨークと、
これら両ヨークの両端部に互いに同心に形成された４個の円孔と、
互いの開口を対向させた状態でこれら各円孔の内側に内嵌固定された、それぞれが有底円筒状である４個の軸受カップと、
結合基部の外周面に４本の軸部を放射状に固設して成り、これら各軸部をこれら各軸受カップ内に挿入した状態で前記両ヨークと組み合わされた十字軸と、
これら各軸部の外周面とこれら各軸受カップの内周面との間に設けられた４組のラジアル軸受と、
を備えた十字軸式自在継手に於いて、
前記十字軸を構成する前記各軸部の基端部外周面と前記結合基部の外面である段差面とを、それぞれ断面形状が部分円弧形である凹曲面により連続させており、これら各凹曲面のうちの少なくとも一部を、前記段差面のうちでこれら各凹曲面の周囲部分よりも、前記各軸部の軸方向に関し、この結合基部の中心寄りに存在させて、前記段差面のうちで前記各軸部の基端部の周囲部分にそれぞれ環状凹部を形成しており、
前記十字軸を構成する前記各軸部と前記各軸受カップとが、これら各軸部の軸方向に関する相対変位を実質的に抑えた状態で組み合わされており、
これら各軸部の基端部にそれぞれの基部を外嵌支持された状態で、これら各軸部の基端部と前記各軸受カップの開口部との間に４個のシールリングが設けられており、
これら各シールリングは、金属製で円環状の芯金と、この芯金を包埋する事でこの芯金により補強された基部及びこの基部から延出したシールリップを備えた弾性材とから成るものであり、
前記各シールリングは、前記基部を前記各軸部の基端部に締り嵌めで外嵌支持すると共に、前記各シールリップを前記各軸受カップの外面に全周に亙って当接させた状態で、前記十字軸と前記両ヨークとの間に組み付けられており、
前記各凹曲面が、断面形状の曲率半径が互いに異なる複数の曲面同士を滑らかに連続させた複合曲面であり、これら各複合曲面を構成するそれぞれ複数の曲面のうち、前記各軸部に連続する内径側曲面の曲率半径が、これら各内径側曲面の周囲に存在する外径側曲面の曲率半径よりも大きく、前記芯金は、円輪部と、この円輪部の内周縁側から前記各軸部の先端側に向けて折れ曲がった円筒部とから成る断面Ｌ字形で、前記円輪部のうちの少なくとも外径寄り部分が、前記段差面に当接している、
事を特徴とする十字軸式自在継手。 A pair of yokes each formed in a bifurcated shape;
Four circular holes formed concentrically with each other at both ends of these yokes,
Four bearing cups each having a bottomed cylindrical shape, fitted and fixed inside each of these circular holes with their openings facing each other;
A cross shaft combined with the yokes in a state in which the four shaft portions are radially fixed to the outer peripheral surface of the coupling base portion, and the shaft portions are inserted into the bearing cups;
4 sets of radial bearings provided between the outer peripheral surface of each shaft part and the inner peripheral surface of each bearing cup ;
In the cross joint universal joint with
The outer peripheral surface of the base end portion of each shaft portion constituting the cross shaft and the step surface which is the outer surface of the coupling base portion are continuously connected by a concave curved surface having a partial arc shape in cross section. At least a part of the curved surface is located closer to the center of the coupling base with respect to the axial direction of each of the shaft portions than the surrounding portion of each concave curved surface of the step surfaces, And forming an annular recess in the peripheral portion of the base end portion of each shaft portion ,
The shaft portions constituting the cross shaft and the bearing cups are combined in a state where the relative displacement in the axial direction of the shaft portions is substantially suppressed,
Four seal rings are provided between the base end portions of the shaft portions and the opening portions of the bearing cups with the base portions fitted and supported on the base end portions of the shaft portions. And
Each of these seal rings is made of a metal and annular cored bar, and a base part reinforced by embedding the cored bar and an elastic material having a seal lip extending from the base part. Is,
Each seal ring is a state in which the base is externally supported by an interference fit to the base end of each shaft portion, and each seal lip is in contact with the outer surface of each bearing cup over the entire circumference. And is assembled between the cross shaft and the yokes,
Each of the concave curved surfaces is a composite curved surface in which a plurality of curved surfaces having different cross-sectional radii of curvature are smoothly connected to each other, and each of the plurality of curved surfaces constituting each of the composite curved surfaces is continuous with each of the shaft portions. The radius of curvature of the inner diameter side curved surface is larger than the radius of curvature of the outer diameter side curved surface existing around each of these inner diameter side curved surfaces, and the cored bar has a ring part and each An L-shaped cross section consisting of a cylindrical portion bent toward the tip end side of the shaft portion, at least a portion near the outer diameter of the annular portion is in contact with the step surface,
A cross joint universal joint characterized by それぞれが二股状に形成された１対のヨークと、
これら両ヨークの両端部に互いに同心に形成された４個の円孔と、
互いの開口を対向させた状態でこれら各円孔の内側に内嵌固定された、それぞれが有底円筒状である４個の軸受カップと、
結合基部の外周面に４本の軸部を放射状に固設して成り、これら各軸部をこれら各軸受カップ内に挿入した状態で前記両ヨークと組み合わされた十字軸と、
これら各軸部の外周面とこれら各軸受カップの内周面との間に設けられた４組のラジアル軸受と、
を備えた十字軸式自在継手に於いて、
前記十字軸を構成する前記各軸部の基端部外周面と前記結合基部の外面である段差面とを、それぞれ断面形状が部分円弧形である凹曲面により連続させており、これら各凹曲面のうちの少なくとも一部を、前記段差面のうちでこれら各凹曲面の周囲部分よりも、前記各軸部の軸方向に関し、この結合基部の中心寄りに存在させて、前記段差面のうちで前記各軸部の基端部の周囲部分にそれぞれ環状凹部を形成しており、
前記十字軸を構成する前記各軸部と前記各軸受カップとが、これら各軸部の軸方向に関する相対変位を実質的に抑えた状態で組み合わされており、
これら各軸部の基端部にそれぞれの基部を外嵌支持された状態で、これら各軸部の基端部と前記各軸受カップの開口部との間に４個のシールリングが設けられており、
これら各シールリングは、金属製で円環状の芯金と、この芯金を包埋する事でこの芯金により補強された基部及びこの基部から延出したシールリップを備えた弾性材とから成るものであり、
前記各シールリングは、前記基部を前記各軸部の基端部に締り嵌めで外嵌支持すると共に、前記各シールリップを前記各軸受カップの外面に全周に亙って当接させた状態で、前記十字軸と前記両ヨークとの間に組み付けられており、
前記各シールリングを構成する弾性材の一部で、前記各基部の軸方向端面の内径寄り部分に、前記十字軸の結合基部の側に突出する凸部を設け、これら各凸部を前記各環状凹部内に進入させている、
事を特徴とする十字軸式自在継手。 A pair of yokes each formed in a bifurcated shape;
Four circular holes formed concentrically with each other at both ends of these yokes,
Four bearing cups each having a bottomed cylindrical shape, fitted and fixed inside each of these circular holes with their openings facing each other;
A cross shaft combined with the yokes in a state in which the four shaft portions are radially fixed to the outer peripheral surface of the coupling base portion, and the shaft portions are inserted into the bearing cups;
4 sets of radial bearings provided between the outer peripheral surface of each shaft part and the inner peripheral surface of each bearing cup ;
In the cross joint universal joint with
The outer peripheral surface of the base end portion of each shaft portion constituting the cross shaft and the step surface which is the outer surface of the coupling base portion are continuously connected by a concave curved surface having a partial arc shape in cross section. At least a part of the curved surface is located closer to the center of the coupling base with respect to the axial direction of each of the shaft portions than the surrounding portion of each concave curved surface of the step surfaces, And forming an annular recess in the peripheral portion of the base end portion of each shaft portion ,
The shaft portions constituting the cross shaft and the bearing cups are combined in a state where the relative displacement in the axial direction of the shaft portions is substantially suppressed,
Four seal rings are provided between the base end portions of the shaft portions and the opening portions of the bearing cups with the base portions fitted and supported on the base end portions of the shaft portions. And
Each of these seal rings is made of a metal and annular cored bar, and a base part reinforced by embedding the cored bar and an elastic material having a seal lip extending from the base part. Is,
Each seal ring is a state in which the base is externally supported by an interference fit to the base end of each shaft portion, and each seal lip is in contact with the outer surface of each bearing cup over the entire circumference. And is assembled between the cross shaft and the yokes,
A part of the elastic material constituting each of the seal rings, provided on the portion near the inner diameter of the axial end surface of each base portion, is provided a convex portion projecting toward the coupling base portion of the cross shaft, and each of these convex portions is each Entering the annular recess,
A cross joint universal joint characterized by それぞれが二股状に形成された１対のヨークと、
これら両ヨークの両端部に互いに同心に形成された４個の円孔と、
互いの開口を対向させた状態でこれら各円孔の内側に内嵌固定された、それぞれが有底円筒状である４個の軸受カップと、
結合基部の外周面に４本の軸部を放射状に固設して成り、これら各軸部をこれら各軸受カップ内に挿入した状態で前記両ヨークと組み合わされた十字軸と、
これら各軸部の外周面とこれら各軸受カップの内周面との間に設けられた４組のラジアル軸受と、
を備えた十字軸式自在継手に於いて、
前記十字軸を構成する前記各軸部の基端部外周面と前記結合基部の外面である段差面とを、それぞれ断面形状が部分円弧形である凹曲面により連続させており、これら各凹曲面のうちの少なくとも一部を、前記段差面のうちでこれら各凹曲面の周囲部分よりも、前記各軸部の軸方向に関し、この結合基部の中心寄りに存在させて、前記段差面のうちで前記各軸部の基端部の周囲部分にそれぞれ環状凹部を形成しており、
前記十字軸を構成する前記各軸部と前記各軸受カップとが、これら各軸部の軸方向に関する相対変位を実質的に抑えた状態で組み合わされており、
これら各軸部の基端部にそれぞれの基部を外嵌支持された状態で、これら各軸部の基端部と前記各軸受カップの開口部との間に４個のシールリングが設けられており、
これら各シールリングは、金属製で円環状の芯金と、この芯金を包埋する事でこの芯金により補強された基部及びこの基部から延出したシールリップを備えた弾性材とから成るものであり、
前記各シールリングは、前記基部を前記各軸部の基端部に締り嵌めで外嵌支持すると共に、前記各シールリップを前記各軸受カップの外面に全周に亙って当接させた状態で、前記十字軸と前記両ヨークとの間に組み付けられており、
前記各シールリングを構成する弾性材の基部の一部で、前記芯金よりも径方向外側部分に、前記十字軸の結合基部の側に突出する第二シールリップを全周に亙って形成し、これら各第二シールリップの先端縁を、前記段差面のうちで前記環状凹部の周囲部分に、全周に亙って当接させている、
事を特徴とする十字軸式自在継手。 A pair of yokes each formed in a bifurcated shape;
Four circular holes formed concentrically with each other at both ends of these yokes,
Four bearing cups each having a bottomed cylindrical shape, fitted and fixed inside each of these circular holes with their openings facing each other;
A cross shaft combined with the yokes in a state in which the four shaft portions are radially fixed to the outer peripheral surface of the coupling base portion, and the shaft portions are inserted into the bearing cups;
4 sets of radial bearings provided between the outer peripheral surface of each shaft part and the inner peripheral surface of each bearing cup ;
In the cross joint universal joint with
The outer peripheral surface of the base end portion of each shaft portion constituting the cross shaft and the step surface which is the outer surface of the coupling base portion are continuously connected by a concave curved surface having a partial arc shape in cross section. At least a part of the curved surface is located closer to the center of the coupling base with respect to the axial direction of each of the shaft portions than the surrounding portion of each concave curved surface of the step surfaces, And forming an annular recess in the peripheral portion of the base end portion of each shaft portion ,
The shaft portions constituting the cross shaft and the bearing cups are combined in a state where the relative displacement in the axial direction of the shaft portions is substantially suppressed,
Four seal rings are provided between the base end portions of the shaft portions and the opening portions of the bearing cups with the base portions fitted and supported on the base end portions of the shaft portions. And
Each of these seal rings is made of a metal and annular cored bar, and a base part reinforced by embedding the cored bar and an elastic material having a seal lip extending from the base part. Is,
Each seal ring is a state in which the base is externally supported by an interference fit to the base end of each shaft portion, and each seal lip is in contact with the outer surface of each bearing cup over the entire circumference. And is assembled between the cross shaft and the yokes,
A second seal lip that protrudes toward the coupling base portion of the cross shaft is formed over the entire circumference at a part of the base portion of the elastic material that constitutes each seal ring in a radially outer portion than the cored bar. The tip edge of each second seal lip is in contact with the peripheral portion of the annular recess in the step surface over the entire circumference.
A cross joint universal joint characterized by 前記段差面のうちで前記環状凹部の周囲部分と、前記芯金を構成する円輪部のうちでこの周囲部分と当接する部分の軸方向片側面とが、平坦面若しくは部分円すい面状の傾斜面であって、前記周囲部分とこの軸方向片側面とが面同士で当接している、請求項１〜４のうちの何れか１項に記載した十字軸式自在継手。 Of the stepped surface, the peripheral portion of the annular recess and the one axial side surface of the portion of the annular ring portion that constitutes the core metal that is in contact with the peripheral portion are inclined in a flat surface or a partial conical surface shape. The cross shaft type universal joint according to any one of claims 1 to 4 , wherein the peripheral portion and the one axial side surface are in contact with each other. それぞれが二股状に形成された１対のヨークと、
これら両ヨークの両端部に互いに同心に形成された４個の円孔と、
互いの開口を対向させた状態でこれら各円孔の内側に内嵌固定された、それぞれが有底円筒状である４個の軸受カップと、
結合基部の外周面に４本の軸部を放射状に固設して成り、これら各軸部をこれら各軸受カップ内に挿入した状態で前記両ヨークと組み合わされた十字軸と、
これら各軸部の外周面とこれら各軸受カップの内周面との間に設けられた４組のラジアル軸受と、
を備えた十字軸式自在継手に於いて、
前記十字軸を構成する前記各軸部の基端部外周面と前記結合基部の外面である段差面とを、それぞれ断面形状が部分円弧形である凹曲面により連続させており、これら各凹曲面のうちの少なくとも一部を、前記段差面のうちでこれら各凹曲面の周囲部分よりも、前記各軸部の軸方向に関し、この結合基部の中心寄りに存在させて、前記段差面のうちで前記各軸部の基端部の周囲部分にそれぞれ環状凹部を形成しており、
前記十字軸を構成する前記各軸部と前記各軸受カップとを、これら各軸部の軸方向に関する相対変位を可能に組み合わせており、
これら各軸部に、弾性材製のシールリングを外嵌し、これら各シールリングを、前記各軸受カップの開口部側端面と、前記十字軸の段差面との間で、軸方向に関して弾性的に圧縮した状態で挟持しており、
前記各凹曲面が、断面形状の曲率半径が互いに異なる複数の曲面同士を滑らかに連続させた複合曲面であり、これら各複合曲面を構成するそれぞれ複数の曲面のうち、前記各軸部に連続する内径側曲面の曲率半径が、これら各内径側曲面の周囲に存在する外径側曲面の曲率半径よりも大きい、
事を特徴とする十字軸式自在継手。 A pair of yokes each formed in a bifurcated shape;
Four circular holes formed concentrically with each other at both ends of these yokes,
Four bearing cups each having a bottomed cylindrical shape, fitted and fixed inside each of these circular holes with their openings facing each other;
A cross shaft combined with the yokes in a state in which the four shaft portions are radially fixed to the outer peripheral surface of the coupling base portion, and the shaft portions are inserted into the bearing cups;
4 sets of radial bearings provided between the outer peripheral surface of each shaft part and the inner peripheral surface of each bearing cup ;
In the cross joint universal joint with
The outer peripheral surface of the base end portion of each shaft portion constituting the cross shaft and the step surface which is the outer surface of the coupling base portion are continuously connected by a concave curved surface having a partial arc shape in cross section. At least a part of the curved surface is located closer to the center of the coupling base with respect to the axial direction of each of the shaft portions than the surrounding portion of each concave curved surface of the step surfaces, And forming an annular recess in the peripheral portion of the base end portion of each shaft portion ,
The shafts constituting the cross shaft and the bearing cups are combined so as to allow relative displacement in the axial direction of the shafts.
A seal ring made of an elastic material is externally fitted to each of these shaft portions, and each of these seal rings is elastic with respect to the axial direction between the opening-side end surface of each bearing cup and the step surface of the cross shaft. It is sandwiched in a compressed state,
Each of the concave curved surfaces is a composite curved surface in which a plurality of curved surfaces having different cross-sectional radii of curvature are smoothly connected to each other, and each of the plurality of curved surfaces constituting each of the composite curved surfaces is continuous with each of the shaft portions. The curvature radius of the inner diameter side curved surface is larger than the curvature radius of the outer diameter side curved surface existing around each inner diameter side curved surface.
A cross joint universal joint characterized by
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