JP2011106534A

JP2011106534A - Fixed type constant-velocity universal joint

Info

Publication number: JP2011106534A
Application number: JP2009260670A
Authority: JP
Inventors: Tomoshige Kobayashi; 智茂小林; Minoru Ishijima; 実石島; Kisao Yamazaki; 起佐雄山崎; Aiko Ishikawa; 愛子石川
Original assignee: NTN Corp; NTN Toyo Bearing Co Ltd
Current assignee: NTN Corp
Priority date: 2009-11-16
Filing date: 2009-11-16
Publication date: 2011-06-02

Abstract

PROBLEM TO BE SOLVED: To provide a fixed type constant-velocity universal joint capable of suppressing the generation of a stick slip and abnormal noise at a cold time due to insufficient lubrication even if it is used in an extremely cold district. SOLUTION: In the fixed type constant-velocity universal joint including an outer joint member 23 having a plurality of track grooves 22 on an inside diameter surface, an inner joint member 26 formed with a plurality of track grooves 25 on an outside diameter surface, a plurality of balls 27 interposed between the track grooves 22 of the outer joint member 23 and the track grooves 25 of the inner joint member 26 and transmitting torque, and a cage 28 retaining the balls 27 and sealing grease in the joint, a number of minute recesses are formed at least in the track grooves 22 of the outer joint member 23 out of the inner surface of the outer joint member 23, the outer surface of the inner joint member 26 and the inner and outer surfaces of the cage 28, the surface roughness Ra of the surface formed with the recesses is made 0.8 or higher, the Rsk value of a parameter of the surface roughness is made to be a negative value, and the abnormal noise at the cold time is suppressed. COPYRIGHT: (C)2011,JPO&INPIT

Description

この発明は、自動車等の車両の動力伝達系に使用されるもので、駆動側と従動側の二軸間で角度変位のみを許容する固定型等速自在継手であって、特に極寒地で使用されても、潤滑不足によるスティックスリップの発生を抑制した固定型等速自在継手に関する。 The present invention is used for a power transmission system of a vehicle such as an automobile, and is a fixed type constant velocity universal joint that allows only an angular displacement between two axes of a driving side and a driven side, and particularly used in a cold region. The present invention also relates to a fixed type constant velocity universal joint that suppresses the occurrence of stick slip due to insufficient lubrication.

固定型等速自在継手であるツェッパ型等速自在継手は、図６に示すように、外側継手部材３、内側継手部材６、ボール７およびケージ８からなる。外側継手部材３の球状内径面１には複数のトラック溝２が円周方向等間隔に、かつ軸方向に沿って形成されている。内側継手部材６の球状外径面４には、外側継手部材３のトラック溝２と対向するトラック溝５が円周方向等間隔に、かつ軸方向に沿って形成されている。外側継手部材３のトラック溝２と内側継手部材６のトラック溝５との間にトルクを伝達する複数のボール７が介在されている。外側継手部材３の球状内径面１と内側継手部材６の球状外径面４の間に、ボール７を保持するケージ８が配置されている。外側継手部材３の外周と、内側継手部材６に連結されたシャフトの外周とをブーツで覆い、継手内部には、潤滑剤としてグリースが封入されている（図示省略）。 A Rzeppa type constant velocity universal joint, which is a fixed type constant velocity universal joint, includes an outer joint member 3, an inner joint member 6, balls 7, and a cage 8, as shown in FIG. A plurality of track grooves 2 are formed on the spherical inner surface 1 of the outer joint member 3 at equal intervals in the circumferential direction and along the axial direction. Track grooves 5 facing the track grooves 2 of the outer joint member 3 are formed on the spherical outer diameter surface 4 of the inner joint member 6 at equal intervals in the circumferential direction and along the axial direction. A plurality of balls 7 that transmit torque are interposed between the track grooves 2 of the outer joint member 3 and the track grooves 5 of the inner joint member 6. Between the spherical inner diameter surface 1 of the outer joint member 3 and the spherical outer diameter surface 4 of the inner joint member 6, a cage 8 that holds the ball 7 is disposed. The outer periphery of the outer joint member 3 and the outer periphery of the shaft connected to the inner joint member 6 are covered with boots, and grease is sealed inside the joint as a lubricant (not shown).

図６に示すように、外側継手部材３の球状内径面１と内側継手部材６の球状外径面４の曲率中心は、いずれも、継手の中心Ｏに形成されている。これに対して、外側継手部材３のトラック溝２の曲率中心Ａと、内側継手部材６のトラック溝５の曲率中心Ｂとは、継手の中心Ｏに対して軸方向に等距離Ｌオフセットされている。これにより、継手が作動角をとった場合、外側継手部材３と内側継手部材６の両軸線がなす角度を二等分する平面上にボール７が常に案内され、二軸間で等速に回転トルクが伝達されることになる。 As shown in FIG. 6, the centers of curvature of the spherical inner surface 1 of the outer joint member 3 and the spherical outer surface 4 of the inner joint member 6 are both formed at the center O of the joint. On the other hand, the center of curvature A of the track groove 2 of the outer joint member 3 and the center of curvature B of the track groove 5 of the inner joint member 6 are offset by an equal distance L in the axial direction with respect to the center O of the joint. Yes. As a result, when the joint takes an operating angle, the ball 7 is always guided on a plane that bisects the angle formed by the two axes of the outer joint member 3 and the inner joint member 6, and rotates at a constant speed between the two axes. Torque is transmitted.

ところで、極寒地に長時間放置された自動車では、その前輪を駆動するために使用される固定型等速自在継手も外気温と同等の低温（例えば、−２０℃以下）となり、その固定型等速自在継手に封入されているグリースも同様の低温になっている。 By the way, in a car left in a very cold region for a long time, the fixed type constant velocity universal joint used to drive the front wheel also has a low temperature (for example, −20 ° C. or less) equivalent to the outside temperature. The grease enclosed in the quick universal joint has a similar low temperature.

このような場合に、固定型等速自在継手が高作動角状態で、この継手にトルクが入力されると、トルク入力した直後に、継手内部のトラック溝と、このトラック溝に案内されるボールとの間で、一時的な潤滑不足によるスティックスリップが発生することがある。このようなスティックスリップが発生すれば異音として運転者に聴こえる場合がある。この異音のことを冷時異音という。この冷時異音はジョイントが回転すれば、その発熱によりジョイント内部温度が上昇しすぐに消えるため、長期に低温環境下に置かれた車両で発進する際のみ問題となり、発進直後以外は問題とならない。 In such a case, if the fixed type constant velocity universal joint is in a high operating angle state and torque is input to the joint, immediately after the torque is input, the track groove inside the joint and the ball guided to the track groove In some cases, stick slip may occur due to temporary lack of lubrication. If such stick-slip occurs, it may be heard by the driver as an abnormal noise. This abnormal noise is called cold abnormal noise. This cold noise is a problem only when starting with a vehicle that has been placed in a low temperature environment for a long period of time because the internal temperature of the joint rises and disappears quickly when the joint rotates. Don't be.

上記のような冷時異音の問題ではないが、従来、等速自在継手の異音の発生を抑えるものがある（特許文献１〜３）。特許文献１に記載のものは、摺動型等速自在継手であって、保持器ポケットの継手軸方向に対向するポケット壁面の周方向中央部を中高として、この中高部において所望のボール締め代にして、異音発生を防止したものである。 Although it is not a problem of the above-mentioned abnormal noise at the time of cold, there exist some which suppress generation | occurrence | production of the abnormal noise of a constant velocity universal joint conventionally (patent documents 1-3). The one disclosed in Patent Document 1 is a sliding type constant velocity universal joint, and a central portion in the circumferential direction of the pocket wall surface facing the joint axial direction of the cage pocket is defined as a middle height. Thus, the generation of abnormal noise is prevented.

特許文献２に記載のものは、固定型等速自在継手の保持器のポケットとボールとの間の隙間を０〜３０μｍとすると共に、トラック溝に摩擦係数０．１３以下のグリースを付着させて、打音の発生を抑えたものである。 Patent Document 2 discloses a fixed type constant velocity universal joint in which a clearance between a cage pocket and a ball is set to 0 to 30 μm, and grease having a friction coefficient of 0.13 or less is adhered to a track groove. , Which suppresses the occurrence of sound.

特許文献３に記載のものは、８個のボールを使用した固定型等速自在継手において、ボールの表面に微少凹部をランダムに多数形成し、ボールの表面粗さをRａ０．０３〜Rａ０．６、ボールの表面粗さパラメータＲsk値を−１．０以下に設定したことで、摩擦を低減させてトルク伝達効率を向上したものである。
実公昭６１−１９２１２号公報実開平５−７５５２５号公報特開２００８−１９０５９６号公報 Patent Document 3 discloses a fixed type constant velocity universal joint using eight balls, in which a large number of minute concave portions are randomly formed on the surface of the ball, and the surface roughness of the ball is set to Ra 0.03 to Ra 0.6. By setting the surface roughness parameter Rsk value of the ball to −1.0 or less, the friction is reduced and the torque transmission efficiency is improved.
Japanese Utility Model Publication No. 61-19212 Japanese Utility Model Publication No. 5-75525 JP 2008-190596 A

従来技術は、前述したような極寒地に長時間放置された自動車における固定型等速自在継手のトラック溝とボールとの間で、一時的な潤滑不足によるスティックスリップ、冷時異音という特殊な環境で発生する異音に着目したものではない。 The conventional technology has special characteristics such as stick-slip due to temporary lack of lubrication, abnormal noise during cold, between the track groove and the ball of the fixed type constant velocity universal joint in an automobile left for a long time in an extremely cold region as described above. It does not focus on abnormal noise generated in the environment.

本願の発明者らは、上記のスティックスリップの原因を究明するために固定型等速自在継手の作動状態を検討した。図６に示す固定型等速自在継手は、ボールが６個のツェッパ型等速自在継手が作動角４０°をとった状態を示す。ラインＬ１は外側継手部材３のトラック溝２とボール７との接触点の軌跡であり、ラインＬ２は内側継手部材６のトラック溝５とボール７との接触点の軌跡である。両トラック溝２、５とボール７とは、接触角をもって接触しているので、ラインＬ１およびラインＬ２は各トラック溝２、５の溝底から離れた位置で接触する。ラインＬ１およびラインＬ２の接触点軌跡の長さを表１に記載した。ラインＬ１の接触点軌跡の長さは、ラインＬ２接触点の軌跡の長さの１．５７倍の長さであり、外側継手部材３のトラック溝２とボール７との接触点の移動量が大きいことがわかる。 The inventors of the present application examined the operating state of the fixed type constant velocity universal joint in order to investigate the cause of the stick-slip described above. The fixed type constant velocity universal joint shown in FIG. 6 shows a state in which the Rzeppa type constant velocity universal joint with six balls takes an operating angle of 40 °. Line L1 is the locus of the contact point between the track groove 2 of the outer joint member 3 and the ball 7, and line L2 is the locus of the contact point between the track groove 5 of the inner joint member 6 and the ball 7. Since both the track grooves 2 and 5 and the ball 7 are in contact with each other with a contact angle, the line L1 and the line L2 are in contact with each other at a position away from the bottom of each track groove 2 and 5. Table 1 shows the lengths of the contact point trajectories of the lines L1 and L2. The length of the contact point locus of the line L1 is 1.57 times the length of the locus of the line L2 contact point, and the amount of movement of the contact point between the track groove 2 of the outer joint member 3 and the ball 7 is as follows. You can see that it ’s big.

図７に示す固定型等速自在継手は、ボールが８個のツェッパ型等速自在継手が作動角４０°をとった状態を示す。図６と同様に、ラインＬ１は外側継手部材３のトラック溝２とボール７との接触点の軌跡であり、ラインＬ２は内側継手部材６のトラック溝５とボール７との接触点の軌跡である。表１に記載したように、ボールが８個のツェッパ型等速自在継手の場合は、ラインＬ１の接触点軌跡の長さは、ラインＬ２接触点の軌跡の長さの１．５３倍の長さであり、外側継手部材３のトラック溝２とボール７との接触点の移動量が大きいことがわかる。

The fixed type constant velocity universal joint shown in FIG. 7 shows a state in which a Zepper type constant velocity universal joint having eight balls takes an operating angle of 40 °. Similarly to FIG. 6, the line L 1 is the locus of the contact point between the track groove 2 of the outer joint member 3 and the ball 7, and the line L 2 is the locus of the contact point between the track groove 5 of the inner joint member 6 and the ball 7. is there. As shown in Table 1, in the case of a Rzeppa constant velocity universal joint with eight balls, the length of the contact point locus of the line L1 is 1.53 times the length of the locus of the line L2 contact point. It can be seen that the amount of movement of the contact point between the track groove 2 of the outer joint member 3 and the ball 7 is large.

上記の結果、外側継手部材３のトラック溝２とボール７との接触点と内側継手部材６のトラック溝５とボール７との接触点との間に周速差が発生し、滑りが生じる。固定型等速自在継手の内部が極低温になると、グリースが流動しにくい状態になり、上記の滑り接触部に一時的な潤滑不足によるスティックスリップが発生すると考えられる。 As a result, a circumferential speed difference is generated between the contact point between the track groove 2 of the outer joint member 3 and the ball 7 and the contact point between the track groove 5 of the inner joint member 6 and the ball 7, thereby causing slippage. When the inside of the fixed type constant velocity universal joint becomes extremely low temperature, the grease becomes difficult to flow, and it is considered that stick slip due to temporary insufficient lubrication occurs in the sliding contact portion.

上記のスティックスリップは、固定型等速自在継手が回転すると、ボールとトラック溝間やケージと内側継手部材および外側継手部材の球面接触部での発熱により、極短時間で固定型等速自在継手の内部に封入されたグリースの温度が上昇するため、スティックスリップは発生しなくなる。また、固定型等速自在継手の内部温度が−２０℃まで低くならない場合や、−２０℃以下でも固定型等速自在継手の作動角が小さい場合にはスティックスリップは発生しないことが分かった。作動角が小さい場合には、トラック溝とボール間の相対変位が小さく、外側継手部材のトラック溝とボールとの接触点と内側継手部材のトラック溝とボールとの接触点との間に発生する周速差による滑り量が少ないためと考えられる。 The above-mentioned stick-slip is a fixed type constant velocity universal joint in a very short time due to heat generated between the ball and the track groove or the spherical contact portion of the cage and the inner joint member and the outer joint member when the fixed type constant velocity universal joint rotates. Since the temperature of the grease sealed in the inside of the chamber rises, stick slip does not occur. It was also found that stick slip does not occur when the internal temperature of the fixed type constant velocity universal joint does not decrease to -20 ° C or when the operating angle of the fixed type constant velocity universal joint is small even at -20 ° C or less. When the operating angle is small, the relative displacement between the track groove and the ball is small and occurs between the contact point between the track groove and the ball of the outer joint member and the contact point between the track groove and the ball of the inner joint member. This is thought to be because there is little slippage due to the difference in peripheral speed.

このような状態に鑑み、極低温かつ高面圧下での潤滑性を向上する手段として、外側継手部材のトラック溝と球状内径面、内側継手部材のトラック溝と球状外径面、およびケージの球状内外径面の表面粗さに着目したものである。 In view of such a situation, as means for improving the lubricity under a cryogenic temperature and high surface pressure, the track groove and spherical inner surface of the outer joint member, the track groove and spherical outer surface of the inner joint member, and the spherical shape of the cage The focus is on the surface roughness of the inner and outer diameter surfaces.

この発明の目的は、極寒地で使用されても、一時的な潤滑不足によるスティックスリップの発生を抑え、冷時異音を抑制した固定型等速自在継手を提供することにある。 An object of the present invention is to provide a fixed type constant velocity universal joint that suppresses occurrence of stick-slip due to temporary insufficient lubrication and suppresses abnormal noise during cold, even when used in extremely cold regions.

この発明に係る固定型等速自在継手は、内径面に複数のトラック溝が形成された外側継手部材と、外径面に複数のトラック溝が形成された内側継手部材と、前記外側継手部材のトラック溝と内側継手部材のトラック溝との間に介在してトルクを伝達する複数のボールと、このボールを保持するケージとを備え、継手内部にグリースを封入した固定式等速自在継手において、前記外側継手部材の内表面、内側継手部材の外表面、およびケージの内外表面のうち、少なくとも、外側継手部材のトラック溝に多数の微少くぼみを形成し、このくぼみ形成面の表面粗さをRa０．８以上とすると共に表面粗さのパラメータのＲsk値を負の値とし、冷時異音を抑制したことを特徴とするものである。 A fixed type constant velocity universal joint according to the present invention includes an outer joint member in which a plurality of track grooves are formed on an inner diameter surface, an inner joint member in which a plurality of track grooves are formed on an outer diameter surface, and the outer joint member. In a fixed type constant velocity universal joint that includes a plurality of balls that transmit torque by interposing between the track groove and the track groove of the inner joint member, and a cage that holds the ball, and in which grease is sealed inside the joint, Of the inner surface of the outer joint member, the outer surface of the inner joint member, and the inner and outer surfaces of the cage, at least a number of minute recesses are formed in the track groove of the outer joint member, and the surface roughness of the recess forming surface is Ra0. The Rsk value of the parameter of the surface roughness is set to a negative value, and abnormal noise during cold is suppressed.

請求項２の発明は、請求項１に記載の固定型等速自在継手において、前記微少くぼみを、外側継手部材の内表面を構成する球状内径面にも形成したものである。 According to a second aspect of the present invention, in the fixed type constant velocity universal joint according to the first aspect, the minute recess is also formed on a spherical inner surface constituting the inner surface of the outer joint member.

請求項３の発明は、請求項１又は請求項２に記載の固定型等速自在継手において、前記微少くぼみを、内側継手部材の外表面を構成するトラック溝および球状外径面にも形成したものである。 According to a third aspect of the present invention, in the fixed type constant velocity universal joint according to the first or second aspect, the minute recess is also formed in a track groove and a spherical outer diameter surface constituting the outer surface of the inner joint member. Is.

請求項４の発明は、請求項１〜３のいずれか１項に記載の固定型等速自在継手において、前記微少くぼみを、ケージの内外表面を構成する球状内径面および球状外径面にも形成したものである。 According to a fourth aspect of the present invention, in the fixed type constant velocity universal joint according to any one of the first to third aspects of the present invention, the small depression is also applied to the spherical inner surface and the spherical outer surface constituting the inner and outer surfaces of the cage. Formed.

請求項５の発明に係る固定型等速自在継手は、内径面に複数のトラック溝が形成された外側継手部材と、外径面に複数のトラック溝が形成された内側継手部材と、前記外側継手部材のトラック溝と内側継手部材のトラック溝との間に介在してトルクを伝達する複数のボールと、このボールを保持するケージとを備え、継手内部にグリースを封入した固定式等速自在継手において、前記外側継手部材の内表面、内側継手部材の外表面およびケージの内外表面のうち、少なくとも内側継手部材の外表面とケージの内外表面に多数の微少くぼみを形成し、この微少くぼみの表面粗さをRa０．８以上とすると共に表面粗さのパラメータのＲsk値を負の値とし、冷時異音を抑制したことを特徴とするものである。 A fixed type constant velocity universal joint according to a fifth aspect of the invention includes an outer joint member having a plurality of track grooves formed on an inner diameter surface, an inner joint member having a plurality of track grooves formed on an outer diameter surface, and the outer surface. Fixed constant velocity free with a plurality of balls that transmit torque by interposing between the track groove of the joint member and the track groove of the inner joint member, and a cage that holds the ball, and in which grease is sealed inside the joint In the joint, among the inner surface of the outer joint member, the outer surface of the inner joint member, and the inner and outer surfaces of the cage, a plurality of minute recesses are formed on at least the outer surface of the inner joint member and the inner and outer surfaces of the cage. The surface roughness is Ra 0.8 or more, and the Rsk value of the surface roughness parameter is set to a negative value to suppress cold noise.

請求項６の発明は、請求項１〜５のいずれか１項に記載の固定型等速自在継手において、前記微少くぼみの表面粗さをRa０．８以上Ra１．５以下の範囲にしたものである。 A sixth aspect of the present invention is the fixed type constant velocity universal joint according to any one of the first to fifth aspects, wherein the surface roughness of the minute recess is in a range of Ra 0.8 or more and Ra 1.5 or less. is there.

請求項７の発明は、請求項１〜６のいずれか１項に記載の固定型等速自在継手において、前記グリースの増ちょう剤をウレア化合物とし、ちょう度を０号から２号としたものである。 The invention according to claim 7 is the fixed type constant velocity universal joint according to any one of claims 1 to 6, wherein the thickener of the grease is a urea compound and the consistency is from 0 to 2. It is.

請求項８の発明は、請求項１〜７のいずれか１項に記載の固定型等速自在継手において、前記外側継手部材および内側継手部材の各トラック溝を軸方向において円弧部のみで形成したものである。 The invention according to claim 8 is the fixed type constant velocity universal joint according to any one of claims 1 to 7, wherein each track groove of the outer joint member and the inner joint member is formed only by an arc portion in the axial direction. Is.

請求項９の発明は、請求項１〜７のいずれか１項に記載の固定型等速自在継手において、前記外側継手部材および内側継手部材の各トラック溝を軸方向において円弧部とストレート部で構成したものである。 A ninth aspect of the present invention is the fixed type constant velocity universal joint according to any one of the first to seventh aspects, wherein each track groove of the outer joint member and the inner joint member is formed by an arc portion and a straight portion in the axial direction. It is composed.

請求項１０の発明は、請求項１〜９のいずれか１項に記載の固定型等速自在継手において、前記外側継手部材および内側継手部材のトラック溝を６本とし、外側継手部材および内側継手部材の対向するトラック溝に介在するボールを６個としたものである。 A tenth aspect of the present invention is the fixed type constant velocity universal joint according to any one of the first to ninth aspects, wherein the outer joint member and the inner joint member have six track grooves, and the outer joint member and the inner joint. Six balls are interposed in the track grooves facing each other.

請求項１１の発明は、請求項１〜９のいずれか１項に記載の固定型等速自在継手において、前記外側継手部材および内側継手部材のトラック溝を８本とし、外側継手部材および内側継手部材の対向するトラック溝に介在するボールを８個としたものである。 The invention according to claim 11 is the fixed type constant velocity universal joint according to any one of claims 1 to 9, wherein the outer joint member and the inner joint have eight track grooves of the outer joint member and the inner joint member. Eight balls are interposed in the track grooves facing each other.

前述のように、外側継手部材のトラック溝とボールとの接触点と内側継手部材のトラック溝とボールとの接触点との周速差が発生し、滑りが生じる。このような固定型等速自在継手の内部が極低温になると、グリースが流動しにくい状態になり、上記の滑り接触部に一時的な潤滑不足が起こり、スティックスリップが発生しやすいという現象をつきとめ、これに着目し、外側継手部材のトラック溝と球状内径面、内側継手部材のトラック溝と球状外径面、およびケージの球状内外径面の表面粗さの新たな設定を見出したものである。本発明はこのような知見に基づくものである。 As described above, the peripheral speed difference between the contact point between the track groove and the ball of the outer joint member and the contact point between the track groove and the ball of the inner joint member occurs, and slipping occurs. When the inside of such a fixed type constant velocity universal joint becomes extremely low temperature, the grease becomes difficult to flow, and there is a temporary shortage of lubrication at the sliding contact portion, and stick slip is likely to occur. Focusing on this, the present inventors have found new settings for the surface roughness of the track groove and spherical inner surface of the outer joint member, the track groove and spherical outer surface of the inner joint member, and the spherical inner and outer surface of the cage. . The present invention is based on such knowledge.

この発明の固定型等速自在継手によれば、外側継手部材の内表面、内側継手部材の外表面、およびケージの内外表面のうち、少なくとも外側継手部材のトラック溝に、あるいは内側継手部材の外表面とケージの内外表面に多数の微少くぼみを形成し、このくぼみ形成面の表面粗さをRa０．８以上とすると共に表面粗さのパラメータのＲsk値を負の値としたので、このような表面粗さを有するトラック溝表面とボール間や各接触部におけるスティックスリップが起こりにくい接触状態に加えて、潤滑剤であるグリースの高い保持能力により、スティックスリップ、冷時異音の発生を抑制することができる。 According to the fixed type constant velocity universal joint of the present invention, among the inner surface of the outer joint member, the outer surface of the inner joint member, and the inner and outer surfaces of the cage, at least the track groove of the outer joint member or the outer surface of the inner joint member. Many small depressions are formed on the surface and the inner and outer surfaces of the cage, the surface roughness of the depression forming surface is Ra 0.8 or more, and the Rsk value of the surface roughness parameter is set to a negative value. In addition to the contact state between the surface of the track groove having the surface roughness and the ball, and the stick slip is unlikely to occur at each contact portion, the high holding ability of the grease as a lubricant suppresses the occurrence of stick slip and cold noise. be able to.

さらに、上記くぼみ形成面の表面粗さをRa０．８以上Ra１．５以下の範囲にしたことにより、上記の作用に加えて、定常走行における音響抑制も維持しつつ、冷時スティックスリップおよび、これによる冷時異音の発生をより一層抑制することができる。 Furthermore, by making the surface roughness of the indentation surface in a range of Ra 0.8 or more and Ra 1.5 or less, in addition to the above-described action, while maintaining acoustic suppression in steady running, It is possible to further suppress the occurrence of abnormal noise during cold.

以下、この発明の実施形態を図１〜図４に基づいて説明する。図１は実施形態の固定型等速自在継手を軸線と平行な面で切断した縦断面図、図２は軸線と直交する断面で切断した横断面図である。図３は図２の要部を示す。 Hereinafter, embodiments of the present invention will be described with reference to FIGS. FIG. 1 is a longitudinal sectional view of a fixed type constant velocity universal joint according to an embodiment cut along a plane parallel to the axis, and FIG. 2 is a transverse sectional view cut along a section orthogonal to the axis. FIG. 3 shows a main part of FIG.

本発明の実施形態の固定型等速自在継手は、図１および図２に示すように、外側継手部材２３、内側継手部材２６、ボール２７およびケージ２８からなる。外側継手部材２３の球状内径面２１には複数のトラック溝２２が円周方向等間隔に、かつ軸方向に沿って形成されている。内側継手部材２６の球状外径面２４には、外側継手部材２３のトラック溝２２と対向するトラック溝２５が円周方向等間隔に、かつ軸方向に沿って形成されている。外側継手部材２３のトラック溝２２と内側継手部材２６のトラック溝２５との間にトルクを伝達する複数のボール２７が介在されている。外側継手部材２３の球状内径面２１と内側継手部材２６の球状外径面２４の間に、ボール２７を保持するケージ２８が配置されている。ケージ２８の球状外径面２８aは外側継手部材２３の球状内径面２１と、ケージ２８の球状内径面２８bは内側継手部材２６の球状外径面２４とそれぞれ嵌合している。ここで、外側継手部材２３のトラック溝２２と球状内径面２１を合わせて外側継手部材２３の内表面という。また、内側継手部材２６のトラック溝２５と球状外径面２４を合わせて内側継手部材２６の外表面といい、ケージ２８の球状外径面２８aと球状内径面２８ｂを合わせてケージ２８の内外表面という。 As shown in FIGS. 1 and 2, the fixed type constant velocity universal joint according to the embodiment of the present invention includes an outer joint member 23, an inner joint member 26, a ball 27, and a cage 28. A plurality of track grooves 22 are formed on the spherical inner surface 21 of the outer joint member 23 at equal intervals in the circumferential direction and along the axial direction. Track grooves 25 facing the track grooves 22 of the outer joint member 23 are formed in the spherical outer diameter surface 24 of the inner joint member 26 at equal intervals in the circumferential direction and along the axial direction. A plurality of balls 27 for transmitting torque are interposed between the track grooves 22 of the outer joint member 23 and the track grooves 25 of the inner joint member 26. A cage 28 for holding a ball 27 is disposed between the spherical inner surface 21 of the outer joint member 23 and the spherical outer surface 24 of the inner joint member 26. The spherical outer diameter surface 28 a of the cage 28 is fitted with the spherical inner diameter surface 21 of the outer joint member 23, and the spherical inner diameter surface 28 b of the cage 28 is fitted with the spherical outer diameter surface 24 of the inner joint member 26. Here, the track groove 22 of the outer joint member 23 and the spherical inner surface 21 are collectively referred to as the inner surface of the outer joint member 23. The track groove 25 and the spherical outer diameter surface 24 of the inner joint member 26 are referred to as the outer surface of the inner joint member 26, and the spherical outer diameter surface 28a and the spherical inner diameter surface 28b of the cage 28 are combined to be the inner and outer surfaces of the cage 28. That is.

外側継手部材２３の球状内径面２１と内側継手部材２６の球状外径面２４の曲率中心は、それぞれ継手の中心Ｏに形成されている。外側継手部材２３のトラック溝２２は、開口側のストレート部２２aと、奥側の円弧部２２bとからなる。一方、内側継手部材２６のトラック溝２５は、開口側の円弧部２５bと奥側のストレート部２５aとからなる。外側継手部材２３のトラック溝２２の円弧部２２bの曲率中心Ｏ１と、内側継手部材２６のトラック溝２５の円弧部２５bの曲率中心Ｏ２とは、継手の中心Ｏに対して軸方向に等距離Ｆオフセットされている。これにより、継手が作動角をとった場合、外側継手部材２３と内側継手部材２６の両軸線がなす角度を二等する平面上にボール２７が常に案内され、二軸間で等速に回転が伝達されることになる。この固定型等速自在継手は、ボールが８個のアンダーカットフリータイプである。尚、この実施形態では、ケージ２８の球状外径面２８aの曲率中心（図示省略）は継手中心Ｏより開口側に、ケージ２８の球状内径面２８bの曲率中心（図示省略）は継手中心Ｏより奥側にそれぞれ小量オフセットして形成されている。 The centers of curvature of the spherical inner surface 21 of the outer joint member 23 and the spherical outer surface 24 of the inner joint member 26 are respectively formed at the center O of the joint. The track groove 22 of the outer joint member 23 includes an opening-side straight portion 22a and a back-side arc portion 22b. On the other hand, the track groove 25 of the inner joint member 26 includes an opening-side arc portion 25b and a back-side straight portion 25a. The center of curvature O1 of the arc portion 22b of the track groove 22 of the outer joint member 23 and the center of curvature O2 of the arc portion 25b of the track groove 25 of the inner joint member 26 are equidistant F in the axial direction with respect to the center O of the joint. It is offset. As a result, when the joint takes an operating angle, the ball 27 is always guided on a plane that bisects the angle formed by the two axes of the outer joint member 23 and the inner joint member 26, and rotates at a constant speed between the two axes. Will be communicated. This fixed type constant velocity universal joint is an undercut free type with eight balls. In this embodiment, the center of curvature (not shown) of the spherical outer surface 28a of the cage 28 is on the opening side from the joint center O, and the center of curvature (not shown) of the spherical inner surface 28b of the cage 28 is from the joint center O. Each is formed with a small offset on the back side.

図３は図２の要部であり、詳しくは外側継手部材２３と内側継手部材２６の対向するトラック溝２２、２５の横断面である。図３に示すように、ボール２７は、外側継手部材２３のトラック溝２２と２点Ｃ１２、Ｃ１３でアンギュラコンタクトし、内側継手部材２６のトラック溝２５と２点Ｃ１５、Ｃ１６でアンギュラコンタクトしている。ボール中心Ｏ５と各接点Ｃ１２、Ｃ１３、Ｃ１５、Ｃ１６を通る直線と、ボール中心Ｏ５と継手中心Ｏを通る直線がなす角度αは３０°〜３８°に設定することが好ましい。本実施形態の８個ボールの継手は、従来の６個ボールの継手に比べ、そのボール径が小さく形成されているが、従来の継手と同等以上の耐久性が得られる。 FIG. 3 is an essential part of FIG. 2, and more specifically, is a cross section of the track grooves 22 and 25 of the outer joint member 23 and the inner joint member 26 facing each other. As shown in FIG. 3, the ball 27 is in angular contact with the track groove 22 of the outer joint member 23 at two points C12 and C13, and is in angular contact with the track groove 25 of the inner joint member 26 at two points C15 and C16. . It is preferable that an angle α formed by a straight line passing through the ball center O5 and each of the contacts C12, C13, C15, C16 and a straight line passing through the ball center O5 and the joint center O is set to 30 ° to 38 °. The eight-ball joint of this embodiment is formed with a smaller ball diameter than the conventional six-ball joint, but the durability equal to or higher than that of the conventional joint is obtained.

このアンダーカットフリータイプの固定型等速自在継手の場合も、前述の図７に示すボールが８個のツェッパ型等速自在継手と同様に、外側継手部材２３のトラック溝２２とボール２７との接触点の移動量が、内側継手部材２６のトラック溝２５とボール２７との接触点の移動量より大きい。したがって、外側継手部材２３のトラック溝２２とボール２７との接触点と内側継手部材２６のトラック溝２５とボール２７との接触点との間に周速差が発生し、滑りが生じる。 Also in the case of this undercut free type fixed type constant velocity universal joint, the ball shown in FIG. 7 is formed between the track groove 22 of the outer joint member 23 and the ball 27 as in the case of the eight Zepper type constant velocity universal joints. The amount of movement of the contact point is larger than the amount of movement of the contact point between the track groove 25 of the inner joint member 26 and the ball 27. Therefore, a circumferential speed difference is generated between the contact point between the track groove 22 of the outer joint member 23 and the ball 27 and the contact point between the track groove 25 of the inner joint member 26 and the ball 27, and slip occurs.

外側継手部材２３の外周と、内側継手部材２６に連結されるシャフト３０の外周とをブーツ３１で覆い、継手内部には、潤滑剤としてグリースが封入されている。 The outer periphery of the outer joint member 23 and the outer periphery of the shaft 30 connected to the inner joint member 26 are covered with a boot 31, and grease is sealed as a lubricant inside the joint.

封入グリースは、基油、増ちょう剤および添加剤からなる。基油としては、鉱物油、エステル系合成油、エーテル系合成油、炭化水素系合成油等の普通に使用される潤滑油又はそれらの混合油が挙げられる。しかしながら、コストや固定型等速自在継手に取り付けられるブーツへの影響を考慮し、鉱物油のみの適用も可能である。 The sealed grease consists of a base oil, a thickener and an additive. Examples of the base oil include commonly used lubricating oils such as mineral oils, ester-based synthetic oils, ether-based synthetic oils, hydrocarbon-based synthetic oils, and mixed oils thereof. However, in consideration of the cost and the effect on the boot attached to the fixed type constant velocity universal joint, it is possible to apply only mineral oil.

増ちょう剤としては、リチウム石けん、リチウムコンプッレクス石けん、カルシウム石けん、カルシウムコンプレックス石けん、アルミニウム石けん、アルミニウムコンプレックス石けん等の石けん類、ジウレア化合物、ポリウレア化合物等のウレア化合物が挙げられるが、特に限定されるものではない。ただし、固定型等速自在継手の耐久性を考慮すると、ジウレア増ちょう剤が望ましい。 Examples of the thickener include soaps such as lithium soap, lithium complex soap, calcium soap, calcium complex soap, aluminum soap, aluminum complex soap, and urea compounds such as diurea compounds and polyurea compounds. It is not something. However, considering the durability of the fixed type constant velocity universal joint, a diurea thickener is desirable.

添加剤としては、固定型等速自在継手の耐久性を考慮し、モリブデン系添加剤や、その他極圧添加剤を０．１〜１０質量％添加してもよい。 As an additive, considering the durability of the fixed type constant velocity universal joint, a molybdenum-based additive or other extreme pressure additive may be added in an amount of 0.1 to 10% by mass.

固定型等速自在継手に封入されるグリースは、その使用状態から、ちょう度０〜２号とするのが好ましく、より好ましくは１号とする。 The grease enclosed in the fixed type constant velocity universal joint preferably has a consistency of 0 to 2, more preferably No. 1 from the state of use.

外側継手部材２３のトラック溝２２、球状内径面２１、内側継手部材２６のトラック溝２５、球状外径面２４やケージ２８の球状外径面２８a、球状内径面２８bの表面には、多数の微少凹部をランダムに形成してあり、その表面粗さ（算術的平均粗さ）を０．８以上とすると共に、表面粗さのパラメータＲsk値を負の値とした。 On the surfaces of the track groove 22, the spherical inner surface 21 of the outer joint member 23, the track groove 25 of the inner joint member 26, the spherical outer surface 24, the spherical outer surface 28a of the cage 28, and the surface of the spherical inner surface 28b, a number of minute Concave portions were randomly formed, the surface roughness (arithmetic average roughness) was 0.8 or more, and the surface roughness parameter Rsk was a negative value.

ここで、表面粗さのＲaとは、ＪＩＳＢ０６０１−２００１において規定する表面粗さパラメータの「高さ方向の振幅平均パラメータ」における算術平均粗さＲａである。また、本文中に表記のＲaの単位はすべて「μｍ」である。 Here, the surface roughness Ra is the arithmetic average roughness Ra in the “amplitude average parameter in the height direction” of the surface roughness parameter defined in JIS B 0601-2001. The unit of Ra described in the text is all “μm”.

表面粗さのパラメータＲsk値とは、ＪＩＳＢ０６０１−２００１において規定する表面粗さの分布曲線の歪度（ＳＫＥＷＮＥＳＳ）、すなわち、表面粗さの平均値に対する凹凸の振幅分布曲線の相対性を表す値である。 The surface roughness parameter Rsk value represents the degree of skewness (SKEWNESS) of the surface roughness distribution curve defined in JIS B 0601-2001, that is, the relativity of the unevenness amplitude distribution curve with respect to the average value of the surface roughness. Value.

パラメータＲsk値は、表面粗さの平均線に対して、振幅分布曲線の山が多いときは正、山と谷が等しいときは零、谷が多いときは負の値となる。したがって、微少凹部を多数形成した外側継手部材２３のトラック溝２２、球状内径面２１、内側継手部材２６のトラック溝２５、球状外径面２４やケージ２８の球状外径面２８a、球状内径面２８bの表面粗さのパラメータＲsk値は負の値となる。 The parameter Rsk value is positive when the amplitude distribution curve has many peaks, zero when the peaks and valleys are equal, and negative when there are many valleys with respect to the average surface roughness line. Accordingly, the track groove 22, the spherical inner diameter surface 21, the track groove 25 of the inner joint member 26, the spherical outer diameter surface 24, the spherical outer diameter surface 28a of the cage 28, and the spherical inner diameter surface 28b, which are formed with a large number of minute recesses. The parameter Rsk value of the surface roughness is negative.

表面粗さの測定箇所は、内側継手部材２６および外側継手部材２３のいずれも次のとおりである。トラック溝２２、２５は、一つのトラック溝底の継手中心Ｏの位置で、軸方向および周方向の２方向の測定結果の平均値とする。球状内径面２１、球状外径面２４は、球面幅中心（継手中心Ｏの位置）の一箇所で、軸方向および周方向の２方向の測定結果の平均値とする。ケージ２８については次のとおりである。球状外径面２８a、球状内径面２８ｂのいずれも、一箇所の柱部中央の継手中心Ｏの位置で、軸方向および周方向の２方向の測定結果の平均値とする。 The measurement points of the surface roughness are as follows for both the inner joint member 26 and the outer joint member 23. The track grooves 22 and 25 are the average value of the measurement results in the two directions of the axial direction and the circumferential direction at the position of the joint center O at the bottom of one track groove. The spherical inner diameter surface 21 and the spherical outer diameter surface 24 are an average value of measurement results in two directions, the axial direction and the circumferential direction, at one location of the spherical width center (position of the joint center O). The cage 28 is as follows. Both the spherical outer diameter surface 28a and the spherical inner diameter surface 28b are average values of measurement results in two axial and circumferential directions at the position of the joint center O at the center of one column portion.

Ｒa値およびＲsk値の測定には、測定器フォームタリサーフ（テーラーホブソン製）で測定する。測定条件として、カットオフ種別：ガウシアン、測定長さ：５λで、カットオフ数：６、カットオフ波長：０．２５ｍｍ、測定倍率：１００００倍、測定速度：０．３０ｍｍ／Ｓとした。 The Ra value and the Rsk value are measured with a measuring instrument foam Talysurf (made by Taylor Hobson). The measurement conditions were cut-off type: Gaussian, measurement length: 5λ, cut-off number: 6, cut-off wavelength: 0.25 mm, measurement magnification: 10,000 times, measurement speed: 0.30 mm / S.

微少くぼみを多数形成する方法としては、例えば、特殊バレル研磨があるが、それ以外にショットピーニング処理等により表面加工を行ってもよい。バレル研磨は、バレル容器に研磨対象物であるワークと研磨材（メディア）を入れ、バレル運動により発生するワークとメディアとの相対摩擦のより表面加工を行う。バレル研磨においてＲsk値のコントロールは、バレル研磨機の回転速度、加工時間、ワーク投入量、チップの種類と大きさ等を選ぶことにより行える。 As a method for forming a large number of minute recesses, for example, there is special barrel polishing, but other than that, surface processing may be performed by shot peening treatment or the like. In barrel polishing, a workpiece and an abrasive (medium), which are objects to be polished, are placed in a barrel container, and surface processing is performed by relative friction between the workpiece and the media generated by barrel movement. In barrel polishing, the Rsk value can be controlled by selecting the rotational speed of the barrel polishing machine, the processing time, the amount of workpiece input, the type and size of the chip, and the like.

ショットピーニングは、処理対象物の表面に小粒子を投射する処理であり、最表面を塑性変形させる条件で行われる。 Shot peening is a process of projecting small particles onto the surface of the object to be processed, and is performed under the condition that the outermost surface is plastically deformed.

以下に本発明の実施例および比較例を説明する。表２に示すように各実施例および比較例の固定型等速自在継手は、両継手部材、ケージに種々レベルの表面粗さおよびＲsk値を有する処理を施した。各実施例および比較例は、いずれも実施形態で説明したボールが８個のアンダーカットフリータイプの固定型等速自在継手である。 Examples of the present invention and comparative examples will be described below. As shown in Table 2, in the fixed type constant velocity universal joints of the examples and comparative examples, both joint members and cages were subjected to treatments having various levels of surface roughness and Rsk values. Each of the examples and comparative examples is an undercut free type fixed type constant velocity universal joint with eight balls described in the embodiment.

各実施例および比較例には実績のある同じグリースを封入し、その組成は、次のとおりである。
基油：ナフテン系鉱物油３０質量％、パラフィン系鉱物油７０質量％（基油として含まれる潤滑成分の全質量に対する質量％）
増ちょう剤：脂肪式ジウレア化合物と芳香族ジウレア化合物の混合１４質量％（グリース組成成分(基油と増ちょう剤と添加剤)の全質量に対する質量％）
添加剤：二硫化モリブデン（ＭｏＳ²）、モリブデンジチオカーバメイト（ＭＯＤＴＣ）、モリブデンジチオフォスフェート（ＭＯＤＴＰ）、Ｓ系極圧添加剤、ＳＮ系極圧添加剤
しかし、封入グリースはこれに限るものではない。 Each example and comparative example is filled with the same proven grease, and the composition is as follows.
Base oil: 30% by mass of naphthenic mineral oil, 70% by mass of paraffinic mineral oil (% by mass with respect to the total mass of the lubricating components contained as the base oil)
Thickener: 14% by mass of fatty diurea compound and aromatic diurea compound (% by mass based on the total mass of grease composition components (base oil, thickener and additive))
Additives: Molybdenum disulfide (MoS ² ), molybdenum dithiocarbamate (MODTC), molybdenum dithiophosphate (MODTP), S-based extreme pressure additive, SN-based extreme pressure additive However, the enclosed grease is not limited thereto.

各実施例および比較例は、表２に示す表面粗さを有する。具体的には、各実施例および比較例として、微少くぼみを形成した部位、そのくぼみ形成面の表面粗さＲａ、Ｒskを表２に示すように種々異ならせたものを準備した。 Each Example and Comparative Example has the surface roughness shown in Table 2. Specifically, as examples and comparative examples, the portions where minute dents were formed and the surface roughnesses Ra and Rsk of the dent forming surfaces were made different as shown in Table 2.

冷時異音の評価試験
冷時異音を計測する試験機を図５に示す。冷時異音の試験条件は、各実施例および比較例ともに次のとおりである。
ジョイント作動角：３５°
回転数：２００rpm
負荷トルク：５００Ｎｍ、
冷蔵温度：−４０℃で６時間以上冷蔵
内側継手部材に貼り付けた熱電対により、試験直前の継手内部温度を計測し、継手内部温度が−３０℃のときの異音レベルを集音マイクにて計測した。その測定結果を表２に示す。
表中の評価基準は次のとおりである。
◎：優れる、○：良好、△：やや劣る、×：不良
また、表中の表面処理実施部位の欄の記号は次のとおりである。
○：表面処理を実施 −：表面処理を未実施

Evaluation Test of Cold Abnormal Noise FIG. 5 shows a testing machine that measures the cold abnormal noise. The test conditions for cold abnormal noise are as follows in each example and comparative example.
Joint working angle: 35 °
Rotation speed: 200rpm
Load torque: 500 Nm,
Refrigeration temperature: Refrigerate at -40 ° C for 6 hours or longer Measure the internal temperature of the joint just before the test with a thermocouple attached to the inner joint member, and use the noise collecting microphone to measure the abnormal noise level when the internal temperature of the joint is -30 ° C. Measured. The measurement results are shown in Table 2.
The evaluation criteria in the table are as follows.
A: Excellent, B: Good, B: Slightly inferior, X: Bad In addition, the symbols in the column for the surface treatment site in the table are as follows.
○: Surface treatment is performed-: Surface treatment is not performed

表２に示す比較例４は現状品のサンプルである。外側継手部材の内表面、内側継手部材の外表面およびケージの内外表面は、いずれも微少くぼみを形成しておらず、その表面粗さＲａ０．５、Ｒsk０．０３である。評価結果として、冷時異音の問題がある。通常異音については当然のことながら問題はない。この比較例４を基準にして、微少くぼみを形成する部位、そのくぼみ形成面の表面粗さＲａ、Ｒskを種々異ならせたサンプルを立案、評価して本発明に至った。 Comparative Example 4 shown in Table 2 is a sample of the current product. The inner surface of the outer joint member, the outer surface of the inner joint member, and the inner and outer surfaces of the cage do not form a minute recess, and have surface roughness Ra0.5 and Rsk0.03. As an evaluation result, there is a problem of abnormal noise during cold. Normally, there is no problem with abnormal noise. Based on the comparative example 4, the present invention was made by designing and evaluating samples in which the minute dents were formed and the surface roughnesses Ra and Rsk of the dent forming surfaces were varied.

各比較例の分析経緯は後述することにして、まず、実施例の評価結果を説明する。
実施例１は、外側継手部材の内表面、内側継手部材の外表面およびケージの内外表面のいずれにも表面粗さＲａ０．８、Ｒsk−０．１２の微少くぼみを形成したもので、優れた冷時異音の抑制効果が認められた。これは、当該表面粗さを有するトラック溝表面とボール間および各接触部におけるスティックスリップが起こりにくい接触面状態に加えて、潤滑剤であるグリースの高い保持能力によるものと考えられる。 The analysis process of each comparative example will be described later. First, the evaluation results of the examples will be described.
Example 1 was formed by forming minute recesses with surface roughness Ra 0.8, Rsk-0.12 on any of the inner surface of the outer joint member, the outer surface of the inner joint member, and the inner and outer surfaces of the cage. An effect of suppressing cold noise was observed. This is considered to be due to the high holding ability of the grease, which is a lubricant, in addition to the contact surface state in which stick slip does not easily occur between the surface of the track groove having the surface roughness and the balls and at each contact portion.

実施例４は、実施例１に対して表面粗さを粗くしたものであり、外側継手部材の内表面、内側継手部材の外表面およびケージの内外表面のいずれにも表面粗さＲａ１．５、Ｒsk−０．５の微少くぼみを形成したものである。実施例４は、同様に優れた冷時異音の抑制効果が認められた。 In Example 4, the surface roughness is made rougher than that in Example 1, and the surface roughness Ra1.5 is applied to any of the inner surface of the outer joint member, the outer surface of the inner joint member, and the inner and outer surfaces of the cage. A small indentation of Rsk-0.5 is formed. In Example 4, an excellent cold noise suppression effect was similarly recognized.

実施例２および実施例５は、微少くぼみを形成する部位を外側継手部材の内表面のみとしたものである。実施例２は、外側継手部材の内表面のみ表面粗さＲａ０．８、Ｒsk−０．４９の微少くぼみを形成したもので、一方、実施例５は、外側継手部材の内表面のみ表面粗さＲａ１．５、Ｒsk−０．５の微少くぼみを形成したものである。実施例２および実施例５は、いずれも冷時異音の抑制効果が優れていた。これは、外側継手部材のトラック溝とボールとの接触点の移動量が大きいことによると考えられる。 In Example 2 and Example 5, only the inner surface of the outer joint member is formed as a site where the minute recess is formed. In Example 2, only the inner surface of the outer joint member is formed with a minute recess having surface roughness Ra0.8, Rsk-0.49. On the other hand, in Example 5, only the inner surface of the outer joint member is surface roughness. A small indentation of Ra1.5 and Rsk-0.5 is formed. In both Example 2 and Example 5, the effect of suppressing cold abnormal noise was excellent. This is considered to be due to the large amount of movement of the contact point between the track groove of the outer joint member and the ball.

実施例３および実施例６は、微少くぼみを形成する部位を内側継手部材の外表面とケージの内外表面としたものである。実施例３は、内側継手部材の外表面とケージの内外表面の双方の表面粗さＲａ０．８、Ｒsk−０．６９の微少くぼみを形成したもので、一方、実施例６は、内側継手部材の外表面とケージの内外表面の双方の表面粗さＲａ１．５、Ｒsk−０．７４の微少くぼみを形成したものである。実施例３および実施例６は、実施例１、実施例２、実施例４および実施例５に比べて冷時異音の抑制効果は少し劣るが、実用上は問題のないレベルであった。 In Example 3 and Example 6, the portion where the minute depression is formed is the outer surface of the inner joint member and the inner and outer surfaces of the cage. In Example 3, a small indentation of surface roughness Ra 0.8, Rsk-0.69 of both the outer surface of the inner joint member and the inner and outer surfaces of the cage is formed, while Example 6 is an inner joint member. A small indentation having surface roughness Ra1.5 and Rsk-0.74 of both the outer surface of the cage and the inner and outer surfaces of the cage is formed. Example 3 and Example 6 were slightly inferior in the effect of suppressing cold abnormal noise as compared with Example 1, Example 2, Example 4 and Example 5, but were practically satisfactory levels.

上記の各実施例は、表２に示すように通常異音においても良好な結果であった。また、微少くぼみの表面粗さがＲａ０．７以下では、通常環境でのグリース保持能力があったとしても、特殊な環境下でのスティックスリップ、冷時異音の発生を抑制できるものではない。一方、微少くぼみの表面粗さがＲａ１．５を越えると、冷時異音を抑制できるものの、常温での評価において異音が発生する通常異音という別の問題が発生することが評価試験の結果より明らかになった。したがって、微少くぼみを形成した表面の粗さはＲａ０．８〜Ｒａ１．５が実用的な範囲となる。 As shown in Table 2, each of the above examples had good results even with normal abnormal noise. In addition, when the surface roughness of the minute dent is Ra 0.7 or less, even if there is a grease retaining ability in a normal environment, it is not possible to suppress the occurrence of stick-slip and cold abnormal noise in a special environment. On the other hand, if the surface roughness of the small dent exceeds Ra1.5, it is possible to suppress the abnormal noise during cold, but another problem of abnormal noise that occurs in the evaluation at room temperature may occur. It became clear from the result. Therefore, Ra0.8 to Ra1.5 is a practical range for the roughness of the surface where the minute depressions are formed.

次に、各比較例の評価結果を説明する。比較例１〜３は、いずれも現状品（比較例４）に対して、表面粗さを良くしたものである（微少くぼみは形成していない）が、冷時異音の評価結果は劣っていた。表面粗さを良好にしても冷時異音の抑制に効果がないことが分かった。 Next, the evaluation results of each comparative example will be described. In Comparative Examples 1 to 3, the surface roughness of the current product (Comparative Example 4) is improved (no minute dents are formed), but the evaluation results of cold noise are inferior. It was It was found that even if the surface roughness was good, there was no effect in suppressing cold noise.

比較例５および比較例６は、現状品（比較例４）レベルの表面粗さで、微少くぼみを形成したものである。表面粗さＲａ０．５で微少くぼみを形成した表面状態では、冷時異音の抑制には十分でないことが判明した。 Comparative Example 5 and Comparative Example 6 are formed with minute depressions at the surface roughness of the current product (Comparative Example 4) level. It was found that the surface state in which a minute dent was formed with a surface roughness Ra of 0.5 was not sufficient to suppress cold abnormal noise.

比較例７〜９は、表面粗さＲａ０．８又は１．５で微少くぼみを形成する部位を内側継手部材の外表面又はケージの内外表面としたものである。比較例７〜９の評価結果より、微少くぼみを形成する部位を内側継手部材の外表面又はケージの内外表面のみとした場合は、冷時異音の抑制効果が十分出ないことが判明した。 In Comparative Examples 7 to 9, a portion where a minute depression is formed with a surface roughness Ra of 0.8 or 1.5 is used as the outer surface of the inner joint member or the inner and outer surfaces of the cage. From the evaluation results of Comparative Examples 7 to 9, it was found that the effect of suppressing the abnormal noise during cold was not sufficiently exhibited when only the outer surface of the inner joint member or the inner and outer surfaces of the cage was formed as the site where the minute depression was formed.

比較例１０〜１３は、表面粗さを非常に粗くし、表面粗さＲａ２．５として微少くぼみを形成したものである。微少くぼみを形成する部位により、冷時異音の抑制効果が良好なものもあるが、このような表面粗さすると、トラック溝とボールとの接触移動に伴う通常異音が大きくなり、実用できないことが判明した。 In Comparative Examples 10 to 13, the surface roughness is very rough, and a small depression is formed as the surface roughness Ra2.5. Some parts have small dents that have a good effect of suppressing abnormal noise during cold, but such surface roughness usually increases the abnormal noise that accompanies the contact movement between the track groove and the ball and is not practical. It has been found.

表２の測定結果は、ボールが８個のアンダーカットフリータイプの固定型等速自在継手のものであるが、ボールが６個のアンダーカットフリータイプの固定型等速自在継手においても同様に冷時異音の抑制効果がある。 The measurement results in Table 2 are for a fixed type constant velocity universal joint with 8 balls undercut free type, but in the same way for a fixed type constant velocity universal joint with 6 balls undercut free. There is an effect of suppressing abnormal noise.

また、図４に示すような、トラック溝が円弧部のみからなるツェッパ型等速自在継手においても、外側継手部材のトラック溝とボールとの接触点と内側継手部材のトラック溝とボールとの接触点との間に発生する周速差による滑り量は、アンダーカットフリータイプの固定型等速自在継手と同様であるので、冷時異音の抑制効果がある。 Also, in the Rzeppa type constant velocity universal joint in which the track groove is composed only of the arc portion as shown in FIG. 4, the contact point between the track groove and the ball of the outer joint member and the contact between the track groove and the ball of the inner joint member. The amount of slip due to the difference in peripheral speed generated between the point and the point is the same as that of the fixed type constant velocity universal joint of the undercut free type, and therefore has an effect of suppressing cold abnormal noise.

この発明に係る固定型等速自在継手の縦断面図である。It is a longitudinal cross-sectional view of the fixed type constant velocity universal joint which concerns on this invention. 前記固定型等速自在継手の横断面図である。It is a cross-sectional view of the fixed type constant velocity universal joint. 図２の要部を拡大した横断面図である。It is the cross-sectional view which expanded the principal part of FIG. 軸方向において円弧部のみで形成されたトラック溝を有する固定型等速自在継手の縦断面図である。It is a longitudinal cross-sectional view of the fixed type constant velocity universal joint which has the track groove formed only in the circular arc part in the axial direction. 冷時異音を計測する試験機の平面図である。It is a top view of the testing machine which measures abnormal noise at the time of cold. 従来の６個ボールの固定型等速自在継手が高作動角をとった場合の、トラック溝とボールの接触状態を示す縦断面図である。FIG. 6 is a longitudinal sectional view showing a contact state between a track groove and a ball when a conventional six-ball fixed type constant velocity universal joint has a high operating angle. 従来の８個ボールの固定型等速自在継手が高作動角をとった場合の、トラック溝とボールの接触状態を示す縦断面図である。FIG. 10 is a longitudinal sectional view showing a contact state between a track groove and a ball when a conventional eight-ball fixed type constant velocity universal joint has a high operating angle.

２１球状内径面
２２トラック溝
２２a ストレート部
２２b 円弧部
２３外側継手部材
２４球状外径面
２５トラック溝
２５ａストレート部
２５b 円弧部
２６内側継手部材
２７ボール
２８ケージ
２８a 球状外径面
２８b 球状内径面
Ｏ継手中心
Ｏ１外側継手部材のトラック溝の円弧部の曲率中心
Ｏ２内側継手部材のトラック溝の円弧部の曲率中心
Ｏ５ボール中心 21 spherical inner surface 22 track groove 22a straight portion 22b arc portion 23 outer joint member 24 spherical outer surface 25 track groove 25a straight portion 25b arc portion 26 inner joint member 27 ball 28 cage 28a spherical outer surface 28b spherical inner surface O joint Center O1 Center of curvature of the arc part of the track groove of the outer joint member O2 Center of curvature of the arc part of the track groove of the inner joint member O5 Center of the ball

Claims

内径面に複数のトラック溝が形成された外側継手部材と、外径面に複数のトラック溝が形成された内側継手部材と、前記外側継手部材のトラック溝と内側継手部材のトラック溝との間に介在してトルクを伝達する複数のボールと、このボールを保持するケージとを備え、継手内部にグリースを封入した固定式等速自在継手において、前記外側継手部材の内表面、内側継手部材の外表面およびケージの内外表面のうち、少なくとも外側継手部材のトラック溝に多数の微少くぼみを形成し、この微少くぼみの表面粗さをRa０．８以上とすると共に表面粗さのパラメータのＲsk値を負の値とし、冷時異音を抑制したことを特徴とする固定式等速自在継手。 An outer joint member having a plurality of track grooves formed on the inner diameter surface, an inner joint member having a plurality of track grooves formed on the outer diameter surface, and between the track grooves of the outer joint member and the track grooves of the inner joint member. In a fixed type constant velocity universal joint that includes a plurality of balls that transmit torque by interposing them and a cage that holds the balls, and in which grease is sealed inside the joint, the inner surface of the outer joint member, the inner joint member Of the outer surface and the inner and outer surfaces of the cage, a large number of minute recesses are formed at least in the track grooves of the outer joint member. The surface roughness of these minute recesses is Ra 0.8 or more, and the Rsk value of the surface roughness parameter is set to A fixed type constant velocity universal joint that is negative and suppresses abnormal noise during cold.

前記微少くぼみを、外側継手部材の内表面を構成する球状内径面にも形成したことを特徴とする請求項１に記載の固定式等速自在継手。 The fixed type constant velocity universal joint according to claim 1, wherein the minute recess is also formed on a spherical inner surface constituting the inner surface of the outer joint member.

前記微少くぼみを、内側継手部材の外表面を構成するトラック溝および球状外径面にも形成したことを特徴とする請求項１又は請求項２に記載の固定式等速自在継手。 3. The fixed type constant velocity universal joint according to claim 1, wherein the minute recess is also formed in a track groove and a spherical outer diameter surface constituting an outer surface of the inner joint member.

前記微少くぼみを、ケージの内外表面を構成する球状内径面および球状外径面にも形成したことを特徴とする請求項１から３のいずれか１項に記載の固定式等速自在継手。 The fixed type constant velocity universal joint according to any one of claims 1 to 3, wherein the minute recesses are also formed on a spherical inner surface and a spherical outer surface constituting the inner and outer surfaces of the cage.

内径面に複数のトラック溝が形成された外側継手部材と、外径面に複数のトラック溝が形成された内側継手部材と、前記外側継手部材のトラック溝と内側継手部材のトラック溝との間に介在してトルクを伝達する複数のボールと、このボールを保持するケージとを備え、継手内部にグリースを封入した固定式等速自在継手において、前記外側継手部材の内表面、内側継手部材の外表面およびケージの内外表面のうち、少なくとも内側継手部材の外表面とケージの内外表面に多数の微少くぼみを形成し、この微少くぼみの表面粗さをRa０．８以上とすると共に表面粗さのパラメータのＲsk値を負の値とし、冷時異音を抑制したことを特徴とする固定式等速自在継手。 An outer joint member having a plurality of track grooves formed on the inner diameter surface, an inner joint member having a plurality of track grooves formed on the outer diameter surface, and between the track grooves of the outer joint member and the track grooves of the inner joint member. In a fixed type constant velocity universal joint that includes a plurality of balls that transmit torque by interposing them and a cage that holds the balls, and in which grease is sealed inside the joint, the inner surface of the outer joint member, the inner joint member Of the outer surface and the inner and outer surfaces of the cage, at least the outer surface of the inner joint member and the inner and outer surfaces of the cage are formed with a number of minute dents. A fixed type constant velocity universal joint characterized in that the Rsk value of the parameter is set to a negative value and noise during cold is suppressed.

前記微少くぼみの表面粗さをRa０．８以上Ra１．５以下の範囲にしたことを特徴とする請求項１〜５のいずれか１項に記載の固定型等速自在継手。 The fixed type constant velocity universal joint according to any one of claims 1 to 5, wherein a surface roughness of the minute recess is in a range of Ra 0.8 or more and Ra 1.5 or less.

前記グリースの増ちょう剤をウレア化合物とし、ちょう度を０号から２号としたことを特徴とする請求項１〜６のいずれか１項に記載の固定型等速自在継手。 The fixed type constant velocity universal joint according to any one of claims 1 to 6, wherein the thickener of the grease is a urea compound and the consistency is from 0 to 2.

前記外側継手部材および内側継手部材の各トラック溝を軸方向において円弧部のみで形成したことを特徴とする請求項１〜７のいずれか１項に記載の固定型等速自在継手。 8. The fixed type constant velocity universal joint according to claim 1, wherein each of the track grooves of the outer joint member and the inner joint member is formed by only an arc portion in the axial direction.

前記外側継手部材および内側継手部材の各トラック溝を軸方向において円弧部とストレート部で構成したことを特徴とする請求項１〜７のいずれか１項に記載の固定型等速自在継手。 8. The fixed type constant velocity universal joint according to claim 1, wherein each track groove of the outer joint member and the inner joint member is configured by an arc portion and a straight portion in the axial direction.

前記外側継手部材および内側継手部材のトラック溝を６本とし、外側継手部材および内側継手部材の対向するトラック溝に介在するボールを６個としたことを特徴とする請求項１〜９のいずれか１項に記載の固定型等速自在継手。 10. The track grooves of the outer joint member and the inner joint member are six, and the balls interposed in the track grooves facing the outer joint member and the inner joint member are six. The fixed type constant velocity universal joint according to item 1.

前記外側継手部材および内側継手部材のトラック溝を８本とし、外側継手部材および内側継手部材の対向するトラック溝に介在するボールを８個としたことを特徴とする請求項１〜９のいずれか１項に記載の固定型等速自在継手。 10. The track groove of the outer joint member and the inner joint member is eight, and the number of balls interposed in the opposed track grooves of the outer joint member and the inner joint member is eight. The fixed type constant velocity universal joint according to item 1.