JP2013087915A - Constant velocity universal joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a constant velocity universal joint, capable of effectively preventing penetration of water or the like from the outside of the joint to the inside thereof, and further effectively preventing boot reversion, boot breakage or the like due to excellent flowing property of air from the inside of the joint to the outside of the joint.SOLUTION: The constant velocity universal joint includes: an outside joint member 23 having an opening and an inside joint member 26 transmitting a torque with the outside joint member 23 through a torque transmitting member while allowing angular displacement. The opening of the outside joint member 23 is sealed by a sealing device 40 having a shaft installation portion 41a fitted and fixed onto a shaft 30 extending from the inside joint member. An air passage 60 reduced in sectional area from the joint inner side toward the joint outer side is provided between an inner diameter surface 61 of the shaft installation portion 41a of the sealing device 40 and an outer diameter surface 62 of a sealing device installation portion 30a of the shaft 30.

Description

  The present invention relates to a constant velocity universal joint, and in particular, is used in a power transmission system of an automobile or various industrial machines. For example, it is incorporated in a propeller shaft of an automobile and includes a sealing device that prevents lubricant leakage from the inside of the joint. It relates to a constant velocity universal joint.

  For example, there are two types of constant velocity universal joints that are used as means for transmitting a rotational force from an automobile engine to wheels at a constant velocity: a fixed constant velocity universal joint and a sliding constant velocity universal joint. Both of these constant velocity universal joints have a structure in which two shafts on the driving side and the driven side are connected so that rotational torque can be transmitted at a constant speed even if the two shafts have an operating angle.

  For example, as a constant velocity universal joint assembled to a propeller shaft used in an automobile such as a 4WD vehicle or an FR vehicle, there is a double offset type sliding constant velocity universal joint.

  As shown in FIG. 8, the double offset type sliding type constant velocity universal joint includes an outer joint member 3 in which linear track grooves 1 extending in the axial direction are formed at a plurality of locations in the circumferential direction of the cylindrical inner peripheral surface 2. An inner joint member 6 in which linear track grooves 4 extending in the axial direction in pairs with the track grooves 1 of the outer joint member 3 are formed at a plurality of locations in the circumferential direction of the spherical outer peripheral surface 5; Ball 7 as a plurality of torque transmitting members interposed between the track groove 1 of the inner joint member 6 and the track groove 4 of the inner joint member 6, the cylindrical inner peripheral surface 2 of the outer joint member 3, and the inner joint member The cage 9 that holds the ball 7 accommodated in the pocket 8 interposed between the spherical outer peripheral surface 5 and the spherical outer peripheral surface 6 is a main component.

  A female spline 11 is formed on the inner diameter surface of the axial hole of the inner joint member 6, and the male spline 13 at the end of the shaft 12 is fitted into the axial hole. And the female spline 11 and the male spline 13 are fitted. A retaining ring 14 is attached to the female spline 11.

  One opening of the outer joint member 3 is sealed with a sealing device 15. The sealing device 15 shown in FIG. 8 is a boot with an adapter, and includes a boot 16 made of a rubber material or a flexible resin material and a metal adapter 17. The boot 16 includes a small-diameter end portion 16a that is externally fitted to the shaft 12, a large-diameter end portion 16b that is connected to the adapter 17, and a bellows-shaped bent portion 16c between the small-diameter end portion 16a and the large-diameter end portion 16b. Become. The small-diameter end portion 16 a of the boot 16 is fastened by the band 20 and fixed to the shaft 12. The adapter 17 includes a caulking portion 17 a that is caulked and fixed to the large-diameter end portion 16 b of the boot 16, and a fitting portion 17 b that is fitted into the opening of the outer joint member 3. A seal member 18 such as an O-ring is fitted on the outer diameter surface of the opening of the outer joint member 3. An end cap 20 is attached to the other opening of the outer joint member 3.

  When a constant velocity universal joint is used for a propeller shaft of an automobile, the operating angle of the outer joint member 23 and the inner joint member 26 is small and is often used under high speed rotation. In such a constant velocity universal joint, the internal pressure rises as the temperature inside the joint increases during high-speed rotation, and the internal pressure fluctuates due to subsequent cooling to negative pressure. Thus, if the boot 16 is deformed excessively due to a change in the internal pressure of the joint, the durability of the boot 16 is lowered.

  For this reason, conventionally, countermeasures for ventilation have been taken to prevent boot inversion and breakage due to increased joint internal pressure. As a measure against the ventilation, a vent is provided as disclosed in Patent Document 1, Patent Document 2, and the like.

Japanese Patent Application Laid-Open No. 2004-156689 JP 2006-275259 A

  The conventional vent is intended to discharge the air inside the joint to the outside of the joint in order to prevent an increase in internal pressure. However, if the vent hole is too large, grease inside the joint is discharged from the vent hole, and grease leakage occurs. In addition, water or the like may enter from the outside of the joint to the inside of the joint, and the life of the joint will be reduced due to the water penetration. On the other hand, if this vent hole is small, the air inside the joint will not easily flow out of the joint, and boot inversion and boot breakage are likely to occur.

  In view of the above problems, the present invention can effectively prevent water from entering the inside of the joint from the outside of the joint, and has excellent air outflow from the inside of the joint to the outside of the joint, such as boot inversion and boot breakage. Provided is a constant velocity universal joint that can effectively prevent the occurrence of the above.

  The constant velocity universal joint of the present invention includes an outer joint member having an opening, and an inner joint member that transmits torque while allowing angular displacement between the outer joint member and the outer joint member via the torque transmission member. A constant velocity universal joint in which an opening portion of an outer joint member is sealed by a sealing device in which a shaft mounting portion is fitted and fixed to a shaft extending from the joint member, and the inner diameter surface of the shaft mounting portion of the sealing device and the shaft sealing device An air passage having a smaller cross-sectional area from the inner side of the joint toward the outer side of the joint is provided between the outer diameter surface of the mounting portion.

  According to the constant velocity universal joint of the present invention, air (air) can flow out from the inside of the joint to the outside of the joint through the air passage. Moreover, since the cross-sectional area of the outside of the joint is set to be small in the air passage, it is possible to prevent the lubricant from flowing out from the opening on the outside of the joint.

  A lubricant reservoir can be provided in the middle of the air passage. By providing the lubricant reservoir, it is possible to improve the function of preventing the lubricant from flowing out to the outside.

  The air passage is set so that the opening inside the joint and the opening outside the joint are displaced in the circumferential direction, and the circumferential length of the air passage is 180 degrees or more in the circumferential direction. It may be inclined to form a certain angle with respect to the shaft, or may be inclined with an angular displacement with respect to the shaft. Furthermore, you may have a branched path as a ventilation path.

  The sealing device includes a boot having a shaft mounting portion, and the boot is a rubber boot or a resin boot. In the case of rubber boots, the boot surface hardness is preferably Hs50 to Hs70, and in the case of resin boots, the boot surface hardness is preferably HDD38 to HDD50. The rubber boot is made of a rubber material such as chloroprene. The resin boot is formed of, for example, a thermoplastic elastomer such as ester, olefin, urethane, amide, or styrene.

  According to the constant velocity universal joint of the present invention, air can flow out from the inside of the joint to the outside of the joint via the air passage, so that it is effective to cause boot reversal or boot breakage due to an increase in internal pressure. Can be prevented. Further, since it is possible to prevent the lubricant from flowing out to the outside of the joint and water from entering the inside of the joint, the joint function (torque transmission function) is hardly deteriorated, and a stable joint mechanism can be exhibited over a long period of time.

  When the lubricant reservoir is provided, the function of preventing the lubricant from flowing out can be improved, and a more stable life can be obtained. In addition, by allowing the opening on the inside of the joint and the opening on the outside of the joint to shift in the circumferential direction, the outflow of lubricant to the outside of the joint and the penetration of water into the joint can be made more stable. Can be prevented.

  The boot may be a rubber boot or a resin boot, and is excellent in versatility. The thermoplastic elastomer has an intermediate property between resin and rubber, and has an advantage of excellent durability such as fatigue and wear, heat aging resistance, and oil resistance.

It is sectional drawing which shows embodiment of the constant velocity universal joint of this invention. FIG. 2 is an enlarged cross-sectional view of a portion where a concave groove of a boot mounted on the constant velocity universal joint shown in FIG. 1 is omitted. FIG. 2 is an enlarged cross-sectional view of a portion corresponding to a concave groove of a boot attached to the constant velocity universal joint shown in FIG. 1. It is an expanded sectional view showing the 1st modification of a ditch of a boot. It is an expanded sectional view showing the 2nd modification of a ditch of a boot. It is an expanded sectional view showing the 3rd modification of a ditch of a boot. It is sectional drawing which shows the modification of the ditch | groove which forms a ventilation path. It is sectional drawing of the conventional constant velocity universal joint.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. FIG. 1 shows a constant velocity universal joint according to the present invention. In this case, the constant velocity universal joint is a double offset type sliding constant velocity universal joint.

  The constant velocity universal joint includes a pair of an outer joint member 23 in which linear track grooves 21 extending in the axial direction are formed at a plurality of positions in the circumferential direction of the cylindrical inner peripheral surface 22 and the track grooves 21 of the outer joint member 23. The linear track groove 24 extending in the axial direction is formed at a plurality of locations in the circumferential direction of the spherical outer peripheral surface 25, the track groove 21 of the outer joint member 23, and the track groove 24 of the inner joint member 26. Between the ball 27, which is a plurality of torque transmitting members that transmit torque, and the cylindrical inner peripheral surface 22 of the outer joint member 23 and the spherical outer peripheral surface 25 of the inner joint member 26. The cage 29 that holds the balls 27 accommodated in the pockets 28 is a main component. The number of balls can be set arbitrarily.

  The shaft 30 is connected to the shaft hole of the inner joint member 26 by spline fitting and is prevented from coming off by a retaining ring 34. That is, a female spline 31 is formed on the inner diameter surface of the shaft hole of the inner joint member 26, and a male spline 32 is formed on the end of the shaft 30. Then, the male spline 32 of the shaft 30 is fitted into the shaft hole of the inner joint member 26, and the male spline 32 is fitted to the female spline 31. A retaining ring 34 is attached to the end of the male spline 32.

  The outer joint member 23 is provided on the side of the opening 33b opposite to the short cylindrical main body 23a in which the track groove 21 is formed on the cylindrical inner peripheral surface 22 and the opening 33a to which a sealing device 40 described later is attached. And an outer flange portion (flange portion) 23b. A seal plate 35 is fitted into the opening 33b on the side where the outer flange 23b is provided. That is, the seal plate 35 includes a disc-shaped main body portion 35a and a short cylindrical portion 35b extending in the axial direction from the outer peripheral edge portion of the disc-shaped main body portion 35a. The short cylindrical portion 35b is an opening 33b of the outer joint member 23. It is press-fitted inside. The sealing device 40 and the seal plate 35 block leakage of a lubricant such as grease sealed in the outer joint member 23.

  Further, the inner part S (the inner joint member 26, the ball 27, and the cage 29) is prevented from coming off from the outer joint member 23 (regulation) on the inner diameter surface of the outer joint member 23 on the both opening portions 33a and 33b side. Retaining rings 35 and 36 are mounted.

  One opening 33 a is sealed by a sealing device 40. The sealing device 40 is a boot with an adapter, and includes a boot 41 and a metal adapter 42. The boot 41 includes a small-diameter end portion 41a that is externally fitted to the shaft 30, a large-diameter end portion 41b that is connected to the adapter 42, and a bellows-shaped bent portion 41c between the small-diameter end portion 41a and the large-diameter end portion 41b. Consists of.

  The boot 41 may be a rubber boot or a resin boot. In the case of rubber boots, the surface hardness of the boot 41 is preferably Hs50 to Hs70, and in the case of resin boots, the surface hardness of the boot 41 is preferably HDD38 to HDD50. The rubber boot is made of, for example, chloroprene rubber or silicon rubber. The resin boot is formed of, for example, a thermoplastic elastomer such as ester, olefin, urethane, amide, or styrene, and a composition containing the thermoplastic elastomer. In the case of a resin boot, if the surface hardness is smaller than the HDD 38, the heat resistance is lowered, the cost of the boot is increased, and the strength is reduced. Conversely, if the surface hardness is larger than the HDD 50, the fatigue, flexibility and assembly are reduced. This will cause a decrease in dexterity. In the case of a rubber boot, if the surface hardness is smaller than Hs50, the strength of the boot 41 is reduced, and conversely, if the surface hardness is larger than Hs70, the fatigue property is reduced.

  The small diameter end portion 41a has a short cylindrical shape, and as shown in FIG. 2, a circumferential groove 43 is provided on the outer diameter surface thereof, and the shaft 30 has a small diameter portion boot as shown in FIG. A mounting portion 30a is provided. Then, the small diameter end portion (shaft mounting portion) 41a of the boot 41 is externally fitted to the boot mounting portion 30a of the shaft 30, and the band 45 is formed in the circumferential groove 43 (see FIG. 2) in this externally fitted state. The small diameter end portion 41 a of the boot 41 is fixed to the shaft 30 by mounting and tightening (reducing the diameter) of the band 45.

  The adapter 42 includes a small diameter portion 42a and a large diameter portion 42b. A caulking portion 42a for caulking and fixing the large diameter end portion 41b of the boot 41 is formed at the end portion of the small diameter portion 42a. Further, a circumferential groove 46 is formed on the outer diameter surface on the one opening side of the outer joint member 23, and the diameter of the large diameter portion 42 b of the adapter 42 is reduced to fit into the circumferential groove 46. A portion 47 is formed. That is, the reduced diameter portion 47 of the adapter 42 is fitted into the circumferential groove 46 of the outer joint member 23 by press fitting the large diameter portion 42 b of the adapter 42 into one opening of the outer joint member 23. A circumferential groove 49 is formed on the outer diameter surface between the circumferential groove 46 and the end face 48 of the outer joint member 23, and a seal ring 50 such as an O-ring of the circumferential groove 49 is fitted therein. It is worn. As shown in FIG. 1, the stepped portion 42 c between the small diameter portion 42 a and the large diameter portion 42 b of the adapter 42 is the end surface 48 of the outer joint member 23 in a state where the adapter 42 is mounted on the outer joint member 23. It will be in the state contact | abutted.

  In this constant velocity universal joint, the air passage 60 (see FIG. 3) is provided between the inner diameter surface 61 of the shaft mounting portion 41a of the sealing device 40 and the outer diameter surface 62 of the sealing device mounting portion (boot mounting portion) 30a of the shaft 30. Is provided. As shown in FIG. 3, the air passage 60 includes a concave groove 63 provided on the inner diameter surface 61 of the shaft mounting portion 41 a and an outer diameter surface 62 of the boot mounting portion 30 a facing the concave groove 63. . In this case, the concave groove 63 is a linear groove extending in the shaft axial direction, and its groove width is reduced from the inside of the joint toward the outside of the joint. That is, when the width dimension of the opening 63a on the joint inner side is W1 and the width dimension of the opening 63b on the joint outer side is W2, W1> W2.

  For this reason, by forming the concave groove 63, the constructed air passage 60 has a cross-sectional area that decreases from the inside of the joint toward the outside of the joint. In this case, W1 is about 1.0 mm to 2.0 mm, W2 is about 0.5 mm to 0.8 mm, and W1 / W2 is about 2.0. In addition, the depth T of the concave groove 63 (see FIG. 7A) is set to about 0.5 mm to 1.5 mm. The number of the concave grooves 63 for configuring the ventilation path 60 can be arbitrarily set.

  In the constant velocity universal joint of the present invention, air (air) can flow out from the inside of the joint to the outside of the joint through the air passage 60. For this reason, it is possible to effectively prevent the occurrence of boot reversal or boot breakage due to an increase in internal pressure. In addition, since the cross-sectional area of the outside of the joint of the air passage 60 is set to be small, it is possible to prevent the outflow of lubricant to the outside of the joint and the intrusion of water or the like into the inside of the joint, thereby reducing the joint function (torque transmission function). It is possible to exert a joint mechanism that is stable over a long period of time.

  The boot 41 may be a rubber boot or a resin boot, and is excellent in versatility. The thermoplastic elastomer has an intermediate property between resin and rubber, and has an advantage of excellent durability such as fatigue and wear, heat aging resistance, and oil resistance. Moreover, the strength is stabilized by setting the surface hardness of the boot as described above.

  Next, FIG. 4 shows a first modification of the air passage 60, and is inclined so as to form a certain angle with respect to the axis of the shaft 30 or the axis of the boot 15. The concave groove 63 is inclined so as to form a certain angle with respect to the axis of the shaft 30 or the axis of the boot 15, and the groove width is reduced from the inside of the joint toward the outside of the joint. That is, when the width dimension of the opening inside the joint is W1, and the width dimension of the opening outside the joint is W2, W1> W2.

  Further, the vent 60 is provided with a lubricant reservoir 65 in the middle thereof. That is, a semicircular recess 65 a is connected to the recess groove 63. Thus, if it inclines so that a fixed angle may be made | formed with respect to the shaft 30, the said ventilation path 60 will be the joint internal side opening part (opening part 63a of the ditch | groove 63), and a joint external side The opening (opening 63b of the groove 63) is displaced in the circumferential direction.

  In the air passage 60 of the second modified example shown in FIG. 5, the air passage 60 is inclined with an angular displacement with respect to the shaft. That is, in the developed view, the groove 63 is meandered in a flat S shape. Further, the ventilation path 60 of the third modification shown in FIG. The branch path 66 is formed by forming an L-shaped groove 66a composed of a short piece 67 and a long piece 68 in communication with the groove 63 on the inner diameter surface 61 of the shaft mounting portion 41a. It is composed. Further, a small recess 69a is formed in a corner portion between the short piece 68 and the long piece 67 of the concave groove 66a, thereby constituting a lubricant reservoir 69.

  4 to 6, the opening on the inner side of the joint (opening 63a of the groove 63) and the opening on the outer side of the joint (opening 63b of the groove 63) are displaced in the circumferential direction. However, in this case, the circumferential length of the air passage 60 is preferably 180 deg or more in the circumferential direction.

  When the lubricant reservoir 65 is provided, the function of preventing the lubricant from flowing out can be improved, and a more stable life can be obtained. Further, by allowing the opening 63a on the inner side of the joint and the opening 63b on the outer side of the joint to be displaced in the circumferential direction, the outflow of the lubricant to the outside of the joint and the intrusion of water or the like into the joint is more stable. Can be prevented.

  By the way, the air passage 60 only needs to have a cross-sectional area that decreases from the inside of the joint toward the outside of the joint. Therefore, when such an air passage 60 is formed, in the case shown in FIG. 7 (a), the groove depth T is constant from the joint inner side toward the joint outer side, and the width dimension W2 of the joint outer side opening 63b is set to the joint inner side opening 63a. The width dimension W1 of the opening 63a on the joint inner side and the width dimension W2 of the opening 63b on the joint outer side are set to be the same, and the groove depth T is As shown in 7 (b), the depth may be shallower from the joint inner side toward the joint outer side. That is, T1> T2, where the groove depth of the opening 63a on the joint inner side is T1, and the groove depth of the opening 63b on the outer side of the joint is T2. Also by setting in this way, the cross-sectional area of the air passage 60 can be reduced from the inside of the joint toward the outside of the joint.

  For this reason, as shown in FIG. 3, even if the concave groove 63 is arranged along the axial direction, as shown in FIGS. Even if the opening 63b of the joint is displaced in the circumferential direction, the width dimension W1 of the joint inner side opening and the width dimension W2 of the joint outer side opening are set to be the same as the groove depth. T may be made shallower from the inside of the joint toward the outside of the joint. The groove depth of the opening 33a on the joint inner side is about 0.5 mm to 1.5 mm, and the width T2 of the opening on the outer side of the joint is about 0.5 mm to 0.8 mm. / T2 is about 2.0.

  As described above, the embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiment, and various modifications are possible. For example, as the sealing device 40, the outer fitting is performed on the boot mounting portion 30a of the shaft 30. A boot (rubber boot or resin boot) comprising a fixed small-diameter portion, a large-diameter portion fitted and fixed to the opening 33a of the outer joint member 23, and a bellows portion connecting the small-diameter portion and the large-diameter portion. It may be configured. Further, the number of the lubricant reservoirs 65 can be increased or decreased arbitrarily. Of course, such a lubricant reservoir 65 may not be provided. In FIGS. 5 and 6, the concave groove 63 is curved as a flat S-shape in the developed view, but may be a combination of linear concave grooves having different inclination angles. In this case, it may be a combination of a linear groove and a curved groove, or a combination of only a linear groove.

  In the embodiment, the air passage 60 is provided by forming the concave groove 63 in the inner diameter surface 61 of the shaft mounting portion 41a of the boot 41. However, the ventilation path 60 is formed on the inner diameter surface 61 of the shaft mounting portion 41a of the boot 41. You may provide such a ditch | groove in the outer diameter surface 62 of the boot mounting part 30a of the shaft 30, without providing in the ditch | groove 63. FIG. Further, a concave groove may be provided on the inner diameter surface 61 of the shaft mounting portion 41 a of the boot 41 and the outer diameter surface 62 of the boot mounting portion 30 a of the shaft 30. Thus, when providing a groove on the boot side and the shaft side, the groove on the boot side and the groove on the shaft side may or may not face each other.

  In the above embodiment, the constant velocity universal joint is a double offset type constant velocity universal joint, but other sliding type constant velocity universal joints such as a tripod type constant velocity universal joint, a cross groove type constant velocity universal joint, etc. There may be. The fixed constant velocity universal joint is not limited to a sliding constant velocity universal joint, and may be a Rzeppa type constant velocity universal joint or an undercut free type constant velocity universal joint.

23 outer joint member 26 inner joint member 27 ball (torque transmission member)
30 Shaft 30a Sealing device mounting part (boot mounting part)
33a Opening part 40 Sealing device 41 Boot 41a Shaft mounting part (small diameter end part)
60 Ventilation path 61 Inner surface 62 Outer surface 63a Opening 63b Opening 65 Lubricant reservoir 66 Branch

Claims (8)

An outer joint member having an opening, and an inner joint member that transmits torque while allowing angular displacement between the outer joint member via the torque transmission member, and a shaft mounting portion on a shaft that extends from the inner joint member Is a constant velocity universal joint in which the opening of the outer joint member is sealed with a sealing device to be externally fitted and fixed,
An air passage having a smaller cross-sectional area from the inner side of the joint toward the outer side of the joint is provided between the inner diameter surface of the shaft mounting portion of the sealing device and the outer diameter surface of the sealing device mounting portion of the shaft. Constant velocity universal joint.   The constant velocity universal joint according to claim 1, wherein a lubricant reservoir is provided in the middle of the air passage.   The air passage is characterized in that the opening inside the joint and the opening outside the joint are displaced in the circumferential direction, and the circumferential length of the air passage is 180 degrees or more in the circumferential direction. The constant velocity universal joint according to claim 1 or 2.   The vent is characterized in that the opening on the inner side of the joint and the opening on the outer side of the joint are displaced in the circumferential direction and are inclined so as to form a certain angle with respect to the shaft. The constant velocity universal joint of any one of Claims 1-3.   The said air passage is inclined with an angular displacement with respect to the said shaft, while the opening part inside a coupling and the opening part outside a coupling are shifted in the circumferential direction. The constant velocity universal joint according to claim 3.   The constant velocity universal joint according to any one of claims 1 to 5, wherein the air passage has a branch passage.   The said sealing device has a boot which has a shaft mounting part, This boot is a rubber boot, The surface hardness of the said boot is Hs50-Hs70, Any one of Claims 1-6 characterized by the above-mentioned. The constant velocity universal joint described in 1.   The said sealing device has a boot which has a shaft mounting part, This boot is a resin boot, The surface hardness of the said boot is HDD38-HDD50, Any one of Claims 1-6 characterized by the above-mentioned. The constant velocity universal joint described in the paragraph.

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