JP2013096545A - Constant-velocity universal joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a constant-velocity universal joint that prevents the lubricating function inside a joint from being impaired even in a severe usage environment in which a boot made of rubber or a resin cannot endure.SOLUTION: The constant-velocity universal joint includes: an outer joint member 43; and an inner joint member 46 that transmits torque to the inside of the outer joint member 43 via a torque transmitting member while permitting angular displacement. An opening of the outer joint member 43 is sealed by a seal member S. The seal member S includes: a metal spherical seal part 80; and an auxiliary seal structure 95 covering the outer periphery of the metal spherical seal part 80. The metal spherical seal part 80 comprises: a spherical seal inner ring 82 having a convex spherical seal surface 81; and a spherical seal outer ring 84 having a concave spherical seal surface 83 in relatively sliding contact with the seal surface 81 of the spherical seal inner ring 82.

Description

  The present invention relates to a constant velocity universal joint.

  For example, constant velocity universal joints used in various industrial machines are equipped with rubber or resin boots as seal members to prevent foreign materials from entering and grease from leaking from the inside. Is common.

  However, the roll driving force transmission device used in continuous casting equipment, which is one of the steel equipment among various industrial machines, transmits the driving force to various rolls. Radiation heat of 80 ° C or higher, high temperature and humidity due to water vapor, scattering of scale Since it is used in an inferior atmosphere due to chemicals or the like, in the case of the sealing member made of the rubber or resin boot described above, the sealing member is liable to deteriorate, leading to a decrease in sealing performance and durability performance.

  For this reason, constant velocity universal joints built in roll drive force transmission devices used in poor atmospheres do not use rubber or resin boots, but adopt a metal spherical seal structure. ing. The constant velocity universal joint includes an outer joint member, an inner joint member, a ball that transmits torque while allowing angular displacement between the outer joint member and the inner joint member, and a cage that holds the ball. And a spherical seal structure is provided between the shaft extending from the inner joint member and the outer joint member (Patent Document 1).

  As shown in FIG. 5, the constant velocity universal joint described in Patent Document 1 or the like has an outer joint member 3 in which a plurality of track grooves 1 extending in the axial direction are formed on the spherical inner peripheral surface 2 at equal intervals in the circumferential direction. An inner joint member 6 in which a plurality of track grooves 4 extending in the axial direction corresponding to the track grooves 1 of the outer joint member 3 are formed on the spherical outer peripheral surface 5 at equal intervals in the circumferential direction, and the outer joint member 3 A plurality of balls 7 which are torque transmission members disposed on a ball track formed in cooperation with the track groove 1 of the inner joint member 6 and the spherical inner peripheral surface 2 of the outer joint member 3. And a cage 8 that holds the ball 7 interposed between the spherical outer peripheral surface 5 of the inner joint member 6.

  By inserting the shaft end of the shaft 10 into the shaft hole of the inner joint member 6 and performing spline fitting, the two are coupled so that torque can be transmitted. Further, the shaft 10 is secured to the inner joint member by fastening the lock plate 12 with bolts 13 to the shaft end of the shaft 10 that is spline-fitted with the inner joint member 6. A flange 15 for connecting and fixing to the rotating shaft is integrally connected to one end of the outer joint member 3.

  In order to close the opening of the outer joint member 3, liquid enters from the inside of the joint and leakage of grease from the inside between the opening end of the outer joint member 3 and the shaft 10 extending from the inner joint member 6. A spherical seal structure 20 is provided to prevent this.

  The spherical seal structure 20 has a metal spherical seal outer ring 22 having a concave spherical seal surface 21 on the inner diameter attached to the outer joint member 3 and a metal having a convex spherical seal surface 23 on the outer diameter. The spherical seal inner ring 24 is slidably mounted on the shaft 10 extending from the inner joint member 6, and the spherical seal inner ring 24 is provided by a spring 25 disposed between the spherical seal inner ring 24 and the inner joint member 6. The sealing surface 23 is brought into elastic contact with the sealing surface 21 of the spherical seal outer ring 22.

  In the constant velocity universal joint described in Patent Document 1, liquid scattered from the periphery adheres to the seal surface 23 of the spherical seal inner ring 24 and the seal surface 21 of the spherical seal outer ring 22 and enters the inside of the joint. In order to prevent the grease from being washed away, the seal surface 23 of the spherical seal inner ring 24 and the seal surface 21 of the spherical seal outer ring 22 are provided with a water repellent coating.

JP 2010-65814 A

  However, when used in the continuous casting equipment of the above steel equipment, there is scattering of chemical water and iron powder, and the water-repellent coating on the seal surface of the spherical seal inner ring and the seal surface of the spherical seal outer ring is stable for a long time. It is difficult to exert the sealed function. That is, foreign matter intrusion into the joint is inevitable due to adhesion and accumulation of impurities.

  Therefore, in view of such circumstances, the present invention intends to provide a constant velocity universal joint that does not impair the lubrication function inside the joint even under severe use environments that cannot be withstood by rubber or resin boots. .

  The constant velocity universal joint of the present invention includes an outer joint member, and an inner joint member that transmits torque while allowing angular displacement between the outer joint member and the outer joint member via the torque transmission member. A constant velocity universal joint whose opening is sealed by a sealing member, the sealing member sliding relative to a spherical seal inner ring having a convex spherical seal surface and the seal surface of the spherical seal inner ring. A spherical metal seal portion including a spherical seal outer ring having a concave spherical seal surface in contact therewith, and a secondary seal structure covering the outer periphery of the spherical metal seal portion.

  According to the constant velocity universal joint of the present invention, it is possible to prevent foreign matters (water, scales, etc.) from entering the metal spherical seal portion with the secondary seal structure.

  It is preferable to dispose an impregnated member impregnated with a lubricant on the track line of the seal surface of the outer surface of the spherical seal or on the outer peripheral side of the inner surface of the spherical seal. By disposing the impregnated member impregnated with the lubricant, the sliding surface between the spherical seal inner ring and the spherical seal outer ring is stably lubricated.

  The spherical seal outer ring includes a short cylindrical portion that is externally fitted to a shaft member that extends from the inner joint member, and a flange-shaped portion that is connected to the short cylindrical portion, and an inner diameter surface of the flange-shaped portion is the seal. A grease nipple for supplying a lubricant is attached to the spherical seal outer ring, and a seal ring is interposed between the inner diameter surface of the short cylindrical portion and the outer diameter surface of the shaft member. Also good.

  With this setting, the supply of lubricant can be stably supplied into the joint by attaching the grease nipple. In addition, since the seal ring is interposed between the inner diameter surface of the short cylinder portion and the outer diameter surface of the shaft member, the sealing performance between the inner diameter surface of the short cylinder portion and the outer diameter surface of the shaft member is improved. be able to.

  The spherical seal outer ring includes a short cylindrical portion that is externally fitted to a shaft member that extends from the inner joint member, and a flange-shaped portion that is connected to the short cylindrical portion, and an inner diameter surface of the flange-shaped portion is the seal. The spherical seal outer ring is provided with a grease nipple for supplying a lubricant, and a labyrinth seal is provided between the inner diameter surface of the short cylindrical portion and the outer diameter surface of the shaft member. May be.

  With this setting, the supply of lubricant can be stably supplied into the joint by attaching the grease nipple. Further, since the labyrinth seal is provided between the inner diameter surface of the cylinder portion and the outer diameter surface of the shaft member, the sealing performance between the inner diameter surface of the cylinder portion and the outer diameter surface of the shaft member can be improved.

  It is preferable to apply a fluororesin-based coating agent to at least one of the seal surface of the spherical seal inner ring and the seal surface of the spherical seal outer ring of the metal spherical seal portion. The spherical core of the sealing surface of the inner ring of the spherical seal and the spherical core of the sealing surface of the outer ring of the spherical seal are preferably concentric with the joint axis.

  The secondary seal structure includes a seal material that is in sliding contact with the outer diameter surface of the spherical seal outer ring, and the seal material is attached to a cover member disposed on the outer diameter side of the outer joint member. The material can be configured to be mounted while being held by the end plate.

  The end plate may be composed of at least two divided pieces. You may comprise the sealing material of a subsealing structure from the ring-shaped body which has a slit.

  In the present invention, in the secondary seal structure, foreign matter (water, scale, etc.) can be prevented from entering the metal spherical seal portion, so that a so-called double seal structure is formed, and as a constant velocity universal joint, Excellent water resistance and dustproof performance. Moreover, the spherical seal inner ring is covered with the spherical seal outer ring, and a high operating angle (about 20 °) is possible.

  Further, by disposing the impregnated member impregnated with the lubricant, the sliding surface between the spherical seal inner ring and the spherical seal outer ring is stably lubricated, and stable torque transmission is possible. In the case where the grease nipple for supplying the lubricant is attached, the lubricant can be stably supplied into the joint, and stable torque transmission can be performed over a long period of time. By providing a seal ring between the inner diameter surface of the short cylindrical portion and the outer diameter surface of the shaft member or by providing a labyrinth seal, the sealing performance can be improved.

  When a fluororesin-based coating agent is applied, it has excellent lubricity, can reduce the sliding resistance during operation, and can obtain smooth operability. When the spherical core of the seal surface of the metal spherical seal portion and the spherical core of the seal surface of the metal spherical seal portion are concentric with the joint axis, the metal spherical seal portion smoothly follows when taking an operating angle. be able to. That is, by adjusting the core position, the dimensional change of the spherical metal seal portion can be suppressed, and the sealing performance can be improved.

  In the case where the seal material of the sub seal structure is attached to the cover member, the seal material is held by the end plate, so the seal material can be attached to the constant velocity universal joint in a stable state, It is possible to stably prevent foreign matter (water, scale, etc.) from entering the spherical metal seal.

  In the case where the end plate is composed of two divided pieces, the sub seal structure can be easily inspected and replaced. If the seal material of the sub seal structure is composed of a ring body having a slit, the inspection and replacement workability of the seal material becomes easy.

It is sectional drawing of the constant velocity universal joint which shows embodiment of this invention. It is a front view of the constant velocity universal joint shown in the said FIG. FIG. 2A is a cross-sectional view of a sub-seal structure used in the constant velocity universal joint shown in FIG. 1, and FIG. 2B is a cross-sectional view of a first modified example. ) Is a cross-sectional view of the second modified example, (d) is a cross-sectional view of the third modified example, and (e) is a cross-sectional view of the first modified example. It is principal part sectional drawing which shows the modification of a spherical seal outer ring. It is sectional drawing of the conventional constant velocity universal joint.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1 and 2 show a constant velocity universal joint according to the present invention. The constant velocity universal joint has an outer joint member 43 in which a plurality of track grooves 41 extending in the axial direction are formed on the inner diameter surface 42 at equal intervals in the circumferential direction. An inner joint member 46 in which a plurality of track grooves 44 extending in the axial direction corresponding to the track grooves 41 of the outer joint member 43 are formed on the outer diameter surface 45 at equal intervals in the circumferential direction, and the outer joint member 43 A plurality of balls 47, which are torque transmitting members disposed on a ball track formed by the track groove 41 and the track groove 44 of the inner joint member 46 in cooperation, the inner diameter surface 42 of the outer joint member 43, and the inner joint member And a cage 48 for holding the balls 47 interposed between the outer diameter surfaces 45 of the 46.

  The outer joint member 43 includes a mouth part 43a having an inner diameter surface 42 in which the track groove 41 is formed, and a short cylinder part 43b on the bottom side of the mouse part 43a. The outer cylinder member 43b is connected to the rotation shaft. A flange member 55 for fixing is integrally connected. The flange member 55 includes a cylindrical main body portion 55a and a disk-shaped outer flange portion 55b provided on the side opposite to the outer joint member of the cylindrical main body portion 55a. The inner diameter of the cylindrical main body 55a is composed of a small-diameter portion 56 on the outer joint member side and a large-diameter portion 57 on the anti-outer joint member side, and at the step portion between the small-diameter portion 56 and the large-diameter portion 57, The plate 58 is engaged. The end plate 58 is held between the retaining ring 59 fitted in the circumferential groove of the large diameter portion 57 and the stepped portion. In FIG. 1, reference numeral 60 a denotes a welded portion that fixes the short cylindrical portion 43 b of the outer joint member 43 and the flange member 55.

  In addition, a recess 61 is provided on the back surface (the surface on the outer joint member side) of the disk-shaped outer flange portion 55b of the flange member 55 over the entire circumference in the circumferential direction. The concave portion 61 does not reach the outer peripheral edge of the disk-shaped outer collar portion 55b. For this reason, the circumferential direction remaining part 62 is formed in the peripheral edge of the back surface of the disk-shaped outer collar part 55b of the flange member 55. And the notch part 63 is provided in the outer peripheral surface of the disk shaped outer collar part 55b at 90 degree pitch along the circumferential direction (refer FIG. 2). In addition, as the height of the circumferential direction remaining part 62, ie, the depth T of the recessed part 61, it is about 1.5 mm-2.0 mm, for example.

  A female spline portion 65 is provided on the inner diameter surface of the shaft hole of the inner joint member 46, and the male spline portion 67 at the end of the shaft 66 is fitted into the shaft hole of the inner joint member 46. The female spline portion 65 of the inner joint member 46 and the male spline portion 67 of the shaft 66 are fitted. Further, the male spline portion 67 of the shaft 66 is fitted with retaining rings 68 and 69 on the distal end side and the proximal end side, respectively, thereby preventing the inner joint member 46 of the shaft 66 from coming off from the axial hole. Yes.

  A flange portion 70 is provided on the anti-male spline portion of the shaft 66, and a flange portion 71 is fixed to the flange portion 70 by welding or the like. The intermediate shaft 72 is connected to the flange portion 71 integrated with the flange portion 70 through a bolt / nut connection. That is, the intermediate shaft 72 has a flange portion 73 facing the flange portion 71 at the end thereof, and the flange portion 71 and 73 are overlapped with each other, and the intermediate shaft 72 is integrated with a fixing tool 75 including a bolt member and a nut member. It becomes. A small flange 76 is connected to the flange 70 of the shaft 66. In FIG. 1, reference numeral 60 b denotes a welded portion that fixes the flange portion 70 and the flange portion 71.

  The opening of the outer joint member 43 is sealed with a sealing member S. The sealing member S includes a metal spherical seal portion 80. The metal spherical seal portion 80 includes a spherical seal inner ring 82 having a seal surface 81 whose outer diameter surface is a convex spherical shape, and a concave spherical seal surface 83 which is in sliding contact with the seal surface 81 of the spherical seal inner ring 82. And a spherical seal outer ring 84 having an inner diameter surface.

  The spherical seal inner ring 82 is formed of a short cylindrical body having a small diameter portion 82 a and a large diameter portion 82 b, and the large diameter portion 82 b is externally fixed to the outer joint member 43. In other words, the spherical seal inner ring 82 has a press-fitting and caulking specification to the outer joint member 43 and does not use a fixture such as a bolt. The seal surface 81 is formed on the outer diameter surface of the open end of the small diameter portion 82a of the spherical seal inner ring 82. The spherical seal outer ring 84 includes a short cylindrical portion 84a that is externally fitted to a shaft member (shaft) 66 that extends from the inner joint member 46, and a flange-shaped portion 84b that is connected to the short cylindrical portion 84a. The inner surface (inner spherical surface) of the flange-shaped portion 84 b constitutes the seal surface 83.

  The short cylinder portion 84a includes a thin portion 85 and a thick portion 86, and an opening 88 to which a grease nipple 87 for supplying lubricant is attached is provided in the thick portion 86. Further, a seal ring 90 such as an O-ring is interposed between the inner diameter surface of the short cylindrical portion 84 a and the outer diameter surface of the shaft member (shaft) 66. That is, the circumferential groove 91 is provided on the inner diameter surface of the thin portion 85, and the seal ring 90 is fitted in the circumferential groove 91. In addition, as this seal ring 90, it is preferable to use the fluororubber thing excellent in slidability.

  An elastic member 92 made of a coil spring or the like is interposed between the flange portion 70 of the shaft 66 and the spherical seal outer ring 84. That is, one end of the elastic member 92 is externally fitted to the small flange portion 76 of the shaft 66, and the other is externally fitted to the thin portion 85 of the short cylindrical portion 84 a of the spherical seal outer ring 84.

  In this way, by interposing the elastic member 92, the spherical seal outer ring 84 is pressed against the spherical seal inner ring 82 by the elastic force of the elastic member 92, and the seal surface 81 of the spherical seal inner ring 82 and the spherical seal outer ring 82 are pressed. 84, the sealing surface 83 is in elastic contact. The spherical core O1 of the seal surface 81 of the spherical seal inner ring 82 and the spherical core O2 of the seal surface 83 of the spherical seal outer ring 84 are set so as to be concentric with the joint axis O.

  Therefore, when the constant velocity universal joint takes an operating angle from the state shown in FIG. 1, the seal surface 81 of the spherical seal inner ring 82 and the seal surface 83 of the spherical seal outer ring 84 are in an elastic contact state. It will slide. Further, the spherical seal inner ring 82 and the spherical seal outer ring 84 are preferably made of SUS material having excellent corrosion resistance, but may be carbon steel for machine structure for the purpose of heat resistance. Furthermore, Si or fluorine rubber having excellent heat resistance may be used.

  In this embodiment, the spherical seal inner ring 82 and the spherical seal outer ring 84 are subjected to electroless nickel plating after material refining (hardness: HRc 20 to 30). As a result, corrosion resistance and wear resistance were improved. It is also preferable to apply a fluororesin coating to at least one of the seal surface 81 of the spherical seal inner ring 82 and the seal surface 83 of the spherical seal outer ring 84. In this case, for example, PTFE (polytetrafluoroethylene) can be coated by heat fusion or the like. In addition to PTFE, PFA, FEP, ETFE, linear and / or cyclic fluoropolymers such as a fluoroalkyl polymer or fluoropolyether polymer having a functional group such as carboxyl at the molecular chain end can be used. .

  Incidentally, the sealing member S is provided with a sub seal structure 95 on the outer peripheral side of the spherical metal seal portion 80. The sub seal structure 95 includes a seal material 99 made of a ring-shaped body attached to a cover member 98 disposed on the outer diameter side of the outer joint member 43. The cover member 98 is formed of a short cylindrical body that is externally fitted and fixed to the outer joint member 43 via a ring-shaped spacer 100. In this case, the spacer 100 is externally fitted to the short cylinder portion 43b side of the mouth portion 43a of the outer joint member 43, and the mouse member 43a of the outer joint member 43 is screwed to the mouse portion 43a of the outer joint member 43 in a state where the cover member 98 is externally fitted thereto. The cover member 98 and the spacer 100 are fixed to the outer joint member 43 through the bolt member 101 to be attached.

  An inner flange portion 102 is provided on the inner diameter portion of the cover member 98 on the side opposite to the spacer, and as shown in FIG. 3A and the like, a circumferential notch 103 for fitting the seal material of the inner flange portion 102 is provided. It has been. The sealing material 99 is fitted into the circumferential cutout 103. Further, an end plate 105 of a flat ring shape is attached to the end face on the counter spacer side of the cover member 98, whereby the sealing material 99 is held in the circumferential notch 103. As shown in FIG. 1, the end plate 105 is fixed to the end face on the counter spacer side of the cover member 98 via a bolt member 106 screwed to the end face of the inner flange portion 102 of the cover member 98. As the sealing material 99, a felt material (nonwoven fabric), a fluororesin such as PTFE, a polyamide-based synthetic fiber, a rubber material (CR, NR, NBR, Si, ACM, FPM / FKM, or the like) can be used. That is, the sealing material 99 can be formed of felt, rubber material, etc., and cost reduction can be achieved.

  In this case, as shown in FIG. 3A, the inner diameter surface 99 a of the seal material 99 comes into sliding contact with the seal surface 83 of the spherical seal outer ring 84. A gap C is formed between the inner diameter 102 a of the inner flange portion 102 of the cover member 98 and the seal surface 83 of the spherical seal outer ring 84. A gap C <b> 1 is formed between the inner diameter edge 105 a of the end plate 105 and the seal surface 83 of the spherical seal outer ring 84.

  Further, as shown in FIG. 1, an impregnation member 110 impregnated with a lubricant is disposed on the track line of the seal surface 83 of the spherical seal outer ring 84 or on the outer peripheral side of the spherical seal inner ring 82. As the impregnating member 110, a material that can be impregnated with a lubricant such as foamed urethane, felt, sponge, or the like and is not easily deteriorated in an environment where the constant velocity universal joint is used is selected. In addition, what is generally used for this kind of constant velocity universal joint can be used as a lubricant.

  3 (b) to 3 (e) show a modification of the sealing material 99. In FIG. 3 (b), a plurality of V-shaped circumferential small grooves 112 having a V-shaped cross section are formed on the inner diameter surface 99a of the sealing material 99. To reduce the sliding contact area and increase the contact surface pressure. In FIG.3 (c), the notch part 113 is provided in the internal diameter surface 99a, and the sliding contact area is made small. In FIG.3 (d), the circumferential groove | channel 114 is formed in the internal diameter surface 99a, and the two circumferential sliding parts 115a and 115b are formed. In FIG. 3E, as in FIG. 3D, the two circumferential sliding portions 115a and 115b are formed, but the sliding contact area of one circumferential sliding portion 115a is increased.

  According to the constant velocity universal joint of the present invention, foreign material (water, scale, etc.) can be prevented from entering the spherical metal seal portion 80 by the secondary seal structure 95. For this reason, what is called a double sealing structure will be comprised, and it will become excellent in water resistance and dustproof performance as a constant velocity universal joint. In addition, the spherical seal inner ring 82 is covered with the spherical seal outer ring 84, so that a high operating angle (about 20 °) is possible.

  By disposing the impregnated member 110 impregnated with the lubricant, the sliding surface between the spherical seal inner ring 81 and the spherical seal outer ring 84 is stably lubricated, and stable torque transmission is possible. In the case where the grease nipple 87 for supplying the lubricant is provided, the lubricant can be stably supplied into the joint, and stable torque transmission can be performed over a long period of time. By interposing the seal ring 90 between the inner diameter surface of the short cylindrical portion 84a and the outer diameter surface of the shaft 66, the sealing performance can be improved.

  In addition, as in this embodiment, the spherical seal inner ring 82 is press-fitted / clamped into the outer joint member 43, and no fasteners such as bolts are used, thereby reducing cost and size. It becomes possible.

  In the case where the sealing material 95 is attached to the cover member 98, the sealing material 95 is held by the end plate 105. Therefore, the sealing material 95 can be attached to the constant velocity universal joint in a stable state. Intrusion of foreign matter (water, scale, etc.) into the spherical metal seal portion 80 can be stably prevented.

  When the spherical core O1 of the seal surface 81 of the spherical seal inner ring 81 and the spherical core O2 of the seal surface 83 of the spherical seal outer ring 84 are concentric with the joint axis O, the metal spherical surface is used when taking an operating angle. The seal part 80 can follow smoothly. That is, by adjusting the core position, the dimensional change of the spherical metal seal portion 80 can be suppressed, and the sealing performance can be improved.

  By applying a fluororesin coating on at least one of the seal surface 81 of the spherical seal inner ring 82 and the seal surface 83 of the spherical seal outer ring 84, the sliding resistance during operation can be lowered, and smooth operation is achieved. Sex can be obtained.

  Further, as shown in FIG. 2, the disk-shaped outer flange portion 55b of the flange member 55 is provided with notches 63 that open to the outer diameter surface at a pitch of 90 ° along the circumferential direction. For this reason, the fastening bolt member (not shown) can be easily fitted into the notch 63, and the fastening workability can be improved. In addition, a recess 61 is provided on the back surface side of the disc-shaped outer flange portion 55b, and the bolt member can be set in the notch portion 63 in a small space.

  By the way, the seal ring 90 is mounted on the inner diameter surface of the short cylindrical portion 84a of the spherical seal outer ring 84. However, a labyrinth seal 120 as shown in FIG. Good. Even if such a labyrinth seal 120 is used, the sealing performance can be improved.

  In the above embodiment, the end plate 105 is constituted by a single flat plate ring body. However, the end plate 105 may be separated into at least two. In other words, the plurality of slits (see FIG. 4) end plate 105 may be composed of a plurality of divided pieces. Thus, if the end plate 105 is constituted by a plurality of divided pieces, the inspection and replacement work of the sealing material 99 held by the end plate 105 becomes easy.

  The sealing material 99 can also be configured by a ring-shaped body having a slit (not shown). Thus, if it has a slit, there exists an advantage by which the replacement | exchange operation | work of the sealing material 99 becomes easy.

  The outer surfaces of the cover member 98 and the end plate 105 surrounding the constant velocity universal joint are preferably coated with urethane coating or the like. By applying the urethane coating, it is possible to improve scratch resistance, water resistance, and corrosion resistance. For this reason, corrosion resistance and wear resistance due to a scale or the like for the constant velocity universal joint can be increased. Here, the urethane coating is formed by coating urethane resin on the surface of the base material (such as the cover member 98 and the end plate 105). Urethane resin is a compound with repeating urethane bonds in the composition, polyisocyanate compound having two or more isocyanate groups (O = C = NRN = C = O) and polyol compound having two or more hydroxyl groups. (HO-R'-OH), polyamine (H2N-R "-NH2), obtained by reacting with compounds with active hydrogen (-NH2, -NH, -CONH-, etc.) such as water. , R ', R ": aliphatic, aromatic, etc.)

  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 metal spherical seal portion 80, a spherical seal inner ring 81, A spherical seal outer ring 84 and a spherical seal middle ring interposed between these inner and outer rings may be provided. In the example shown in the figure, the constant velocity universal joint was a Rzeppa type fixed constant velocity universal joint, but even undercut free type fixed type constant velocity universal joints, double offset type, cross groove type, Alternatively, a sliding type constant velocity universal joint such as a tripod type may be used.

43 Outer joint member 46 Inner joint member 47 Ball (torque transmission member)
80 Metal spherical seal portions 81 and 83 Seal surface 82 Spherical seal inner ring 84 Spherical seal outer ring 84a Short cylinder portion 84b Saddle-shaped portion 87 Grease nipple 90 Seal ring 95 Sub seal structure 98 Cover member 99 Seal material 105 End plate 110 Impregnation Member 120 Labyrinth seal O Joint axis O1, O2 Spherical core S Sealing member

Claims (7)

An outer joint member and an inner joint member that transmits torque while allowing angular displacement between the outer joint member and the outer joint member, and the opening of the outer joint member is sealed with a sealing member. Constant velocity universal joint,
The sealing member is a metal spherical surface composed of a spherical seal inner ring having a convex spherical seal surface and a spherical seal outer ring having a concave spherical seal surface that is in sliding contact with the seal surface of the spherical seal inner ring. A constant velocity universal joint comprising: a seal portion; and a secondary seal structure covering an outer periphery of the spherical metal seal portion.   2. The constant velocity universal joint according to claim 1, wherein an impregnated member impregnated with a lubricant is disposed on a track line of a seal surface of the outer surface of the spherical seal or on an outer peripheral side of the inner surface of the spherical seal.   The spherical seal outer ring includes a short cylindrical portion that is externally fitted to a shaft member that extends from the inner joint member, and a flange-shaped portion that is connected to the short cylindrical portion, and an inner diameter surface of the flange-shaped portion is the seal. The spherical seal outer ring is provided with a grease nipple for supplying a lubricant, and a seal ring is interposed between the inner diameter surface of the cylindrical portion and the outer diameter surface of the shaft member. The constant velocity universal joint according to claim 1 or 2.   The spherical seal outer ring includes a short cylindrical portion that is externally fitted to a shaft member that extends from the inner joint member, and a flange-shaped portion that is connected to the short cylindrical portion, and an inner diameter surface of the flange-shaped portion is the seal. A grease nipple for supplying a lubricant is attached to the spherical seal outer ring, and a labyrinth seal is provided between the short cylindrical portion and the outer diameter surface of the shaft member. The constant velocity universal joint of any one of Claims 1-3.   5. The fluororesin-based coating agent is applied to at least one of the seal surface of the spherical seal inner ring and the seal surface of the spherical seal outer ring of the metal spherical seal portion. The constant velocity universal joint described in 1.   The spherical core of the seal surface of the inner ring of the spherical seal and the spherical core of the seal surface of the outer ring of the spherical seal are concentric with the joint axis. The constant velocity universal joint described.   The secondary seal structure includes a seal material that is in sliding contact with the outer diameter surface of the spherical seal outer ring, and the seal material is attached to a cover member disposed on the outer diameter side of the outer joint member. The constant velocity universal joint according to any one of claims 1 to 6, wherein the material is mounted in a state of being held by an end plate.

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