JP6644528B2 - Seal structure and constant velocity universal joint - Google Patents

Description

  The present invention relates to a seal structure and a constant velocity universal joint having the seal structure.

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

  However, among constant velocity universal joints applied to power transmission mechanisms of various industrial machines, when used in steel equipment, etc., they are used in harsh environments (bad atmosphere) where hot water containing chemical water or iron powder scatters. Often done. For this reason, in a constant velocity universal joint used in such a poor atmosphere, conventionally, various proposals have been made to adopt a metal spherical seal structure without using a seal member made of rubber or resin boots. (Patent Document 1 and Patent Document 2).

  A constant velocity universal joint using a metal spherical seal structure has, for example, a configuration as shown in FIG. This constant velocity universal joint has an outer joint member 3 in which a plurality of track grooves 2 are formed in the inner diameter surface 1 along the axial direction, and a plurality of track grooves 5 in the outer diameter surface 4 along the axial direction. An inner joint member, a plurality of torque transmitting balls disposed on a ball track formed by a pair of the track groove of the outer joint member and the track groove of the inner joint member, and an inner diameter of the outer joint member; A cage (8) is provided between the surface (1) and the outer diameter surface (4) of the inner joint member (6) and holds a torque transmitting ball (7).

  A female spline 11 is formed on the inner surface of the hole of the inner joint member 6, and a male spline 13 of the shaft 12 is fitted into the hole of the inner joint member 6. The spline 11 is fitted.

  One opening of the outer joint member 3 is closed by a seal structure S. The seal structure S is a spherical seal structure formed by metal-to-metal spherical contact without using a boot. The seal inner ring 20 on the shaft side, the seal outer ring 21 on the outer joint member side, and the seal inner ring 20 And an elastic member 22 pressed to the side.

  The seal inner ring 20 includes a bowl-shaped main body 20a having a convex spherical sealing surface 23, and a short cylindrical portion 20b connected to the inner diameter of the main body 20a. Further, the seal outer ring 21 is formed of a ring body having an inner flange portion 21a on the inner diameter portion on the outer side of the joint. The seal outer ring 21 is fixed to the outer joint member 3 via a bolt member (not shown) screwed to the outer joint member 3. The inner flange portion 21a of the seal outer ring 21 includes a radial portion 25 extending in the radial direction, and an extending portion 26 extending to the inner diameter portion of the radial portion 25 so as to decrease in diameter from outside the joint toward the inside of the joint. Prepare. Then, the end face of the extending portion 26 becomes a concave curved sealing surface 27 that slides on the sealing surface 23. A cylindrical spacer 28 is fitted on the shaft 12. The seal inner ring 20 is fitted on the spacer 28.

  The elastic member 22 is formed of a coil spring and is interposed between the seal inner ring 20 and the inner joint member 6. In this case, the seal inner ring 20 is provided with a circumferential recess 29 between the outer diameter surface of the short cylindrical portion 20b and the inner surface of the main body portion 20a. For this reason, one end 22 a of the elastic member 22 is fitted into the circumferential recess 29, and the other end 22 b is in contact with the end face of the inner joint member 6. Therefore, the seal inner ring 20 is pressed outward by the elastic force of the elastic member 22.

  That is, as shown by the imaginary line in FIG. 3, even when the constant velocity universal joint has an operating angle (for example, 10 °), the elastic force of the elastic member 22 causes the sealing surface 23 of the seal inner ring 20 to be closed. And the seal 27 of the seal outer ring 21 are set so as to be pressed against each other. For this reason, between the seal surface 23 of the seal inner ring 20 and the seal surface 27 of the seal outer ring 21, the sealing performance is excellent and a stable sealing function is exhibited.

JP 2010-65814 A JP 2011-190871 A

  As described above, in the case of a constant velocity universal joint having a metal spherical seal structure, a metal sliding contact between the seal surface of the seal inner ring and the seal surface of the seal outer ring. In other words, the seal portions that are mated by the spherical surface are rubbed with the rotation. For this reason, the seal surface is easily worn, and if worn, the sealing function is reduced, and the life of the sealing function in such a sealing structure is short.

  Therefore, the present invention provides a seal structure and a constant velocity universal joint capable of extending the life of the seal function.

Seal structure of the present invention includes an outer joint member having a plurality of track grooves are formed on the inner surface, an inner joint member having a plurality of track grooves are formed on the outer surface, the track groove and the inner joint member of the outer joint member A torque transmitting member interposed between the outer joint member and a track groove , and the outer joint member includes a mouth portion having a bottom wall, and a shaft is fitted into the mouth portion of the outer joint member. A seal structure for sealing an opening between the mouth portion and the shaft in the constant velocity universal joint, wherein the metal spherical seal inner ring has a convex spherical seal surface, and a seal surface of the metal spherical seal inner ring. And a metal spherical seal outer ring having a concave spherical seal surface which is relatively in sliding contact with the outer joint member via a first bearing structure on the outer joint member side. Around Mounted in the braking state, the metal spherical seal outer ring, in which co-rotation of the inner joint member through the second bearing structure is mounted in a state of being restricted to the inner joint member.

  According to the seal structure of the present invention, the metal spherical seal inner ring is mounted on the outer joint member side in a state in which rotation with the outer joint member is restricted via the first bearing structure, and the metal spherical seal outer ring is provided. Are mounted on the inner joint member side in a state where rotation with the inner joint member is restricted via the second bearing structure, so that when torque is transmitted by this constant velocity universal joint, The inner ring of the metal spherical seal and the outer ring of the metal spherical seal do not rotate. Therefore, rubbing due to rotation does not occur in the seal portions that are joined by the spherical surface.

  The first bearing structure portion includes an outer joint member-side pedestal mounted on the opening of the outer joint member, and a rolling bearing mounted on the outer joint member-side pedestal. The spherical seal inner ring may be configured to be mounted on the outer joint member side base. With this configuration, the first bearing structure and the second bearing structure can be stably provided.

  The inner joint member is formed of a shaft having an inner race component having a track groove into which the torque transmitting member is fitted, and the second bearing structure includes a rolling bearing mounted on the shaft. The rolling bearing may be provided with the metal spherical seal outer ring. As described above, when the inner joint member is formed by the shaft having the inner ring forming portion in which the track groove into which the torque transmitting member is fitted is formed, it is necessary to perform spline fitting between the shaft and the inner joint member. There is no. For this reason, the assemblability can be improved. If spline fitting is necessary, when the pitch circle of the torque transmitting ball is reduced, the thickness between the spline from the ball groove bottom (track groove bottom) of the inner joint member may be insufficient and the strength may not be secured. is there. On the other hand, in the integrated structure, the pitch circle of the torque transmitting ball can be reduced without insufficient strength.

A shaft-side pedestal and an elastic member are disposed on the shaft, and the elastic force of the elastic member is transmitted to the shaft-side pedestal and the bearing of the second shaft portion, so that the metal spherical seal outer ring is provided inside the metal spherical seal. It is preferable that the seal surface of the metal spherical seal outer ring and the seal surface of the metal spherical seal inner ring be in close contact with each other by being pressed to the ring side . With such a configuration, it is possible to improve the close contact between the sealing surface of the metal spherical seal outer ring and the sealing surface of the metal spherical seal inner ring, and exhibit a stable sealing function.

Constant velocity universal joint of the present invention includes an outer joint member having a plurality of track grooves are formed on the inner surface, an inner joint member having a plurality of track grooves are formed on the outer surface, and the track grooves of the outer joint member inner A torque transmitting member interposed between the joint member and the track groove to transmit torque, and the outer joint member includes a mouth portion having a bottom wall, and a shaft is fitted into the mouth portion of the outer joint member. A constant velocity universal joint, wherein the opening of the outer joint member is sealed by the seal structure.

  According to the constant velocity universal joint of the present invention, the metal spherical seal inner ring and the metal spherical seal outer ring do not rotate when torque is transmitted by the constant velocity universal joint. Therefore, rubbing due to rotation does not occur in the seal portions that are joined by the spherical surface.

  In the present invention, since the rubbing due to the rotation does not occur in the seal portions joined by the spherical surface, it is possible to extend the life of the seal function. Moreover, since the outer ring of the spherical seal and the inner ring of the spherical seal are made of metal, the seal structure can withstand severe use conditions.

It is sectional drawing of the constant velocity universal joint using the seal structure of this invention. FIG. 2 is an enlarged sectional view of a main part of the constant velocity universal joint shown in FIG. 1. It is sectional drawing of the constant velocity universal joint using the conventional seal structure.

  An embodiment of the present invention will be described below with reference to FIGS. 1 and 2 show a constant velocity universal joint according to the present invention. In this constant velocity universal joint, an outer joint member 33 having a plurality of (for example, six) track grooves 32 formed on an inner diameter surface 31 and a plurality (for example, six) track grooves 35 formed on an outer diameter surface 34. And a plurality (for example, six) of torque transmitting members interposed between the track groove 31 of the outer joint member 33 and the track groove 35 of the inner joint member 36 for transmitting torque. A torque transmitting ball 37 and a retainer 38 for holding the ball 37 between the inner diameter surface 31 of the outer joint member 33 and the outer diameter surface 34 of the inner joint member 36 are provided.

  The outer joint member 33 includes a mouth portion 41 having a bottom wall 41a, and a flange portion 42 provided continuously with the bottom wall 41a of the mouth portion 41. A track groove 32 is formed on the inner diameter surface 31 of the mouth part 41.

  The inner joint member 36 is formed by a shaft 40 having an inner ring forming portion 39 in which a track groove 35 in which the torque transmitting ball 37 as the torque transmitting member is fitted is formed. The shaft 40 has an outer flange portion 40a, a large-diameter convex portion 40b, a medium-diameter convex portion 40c, and a small-diameter convex portion 40d formed at a base end thereof.

  The opening of the outer joint member 33, that is, the opening of the mouth part 41 is sealed by the seal structure S. The seal structure S has a metal spherical seal inner ring 52 having a convex spherical seal surface 51, and a metal spherical surface having a concave spherical seal surface 53 slidably in contact with the seal surface 51 of the metal spherical seal inner ring 52. And a seal outer ring 54. Note that the metal spherical seal inner ring 52 and the metal spherical seal outer ring 54 are preferably made of a SUS-based material having excellent corrosion resistance. However, if heat resistance is intended, carbon steel for machine structure may be used. Good.

  The metal spherical seal inner ring 52 includes a ring body portion 55 having an outer diameter surface that is a convex spherical surface and constituting the seal surface 51, and a large-diameter short cylindrical portion 56 connected to the ring body portion 55. A rolling bearing 57 is fitted to the short cylindrical portion 56. Further, the rolling bearing 57 is mounted on a pedestal (outer joint member side pedestal) 58 which is mounted on the opening of the mouth portion 41 of the outer joint member 33. In this case, the rolling bearing 57 and the outer joint member side pedestal 58 constitute a first bearing structure portion M1 described later.

  The outer joint member-side pedestal 58 includes a short cylindrical main body 59 having a circumferential cutout 59 a on the outer joint surface opposite the joint, and a thin ring portion 60 connected to the main body 59. Then, the opening of the mouth portion 41 of the outer joint member 33 is fitted and fixed to the ring portion 60. In this case, a circumferential concave portion 43 is provided on the outer diameter surface of the opening of the mouth portion 41 of the outer joint member 33, and the ring portion 60 is fitted into the circumferential concave portion 43.

  Further, a spherical seat 58 a is provided at a joint side corner portion inside the pedestal 58, and the spherical seat 58 a slides on an outer diameter portion 38 a of the retainer 38 on the joint opening side. Further, a spherical seat 41b is provided at a corner between the bottom wall 41a of the outer joint member 33 and the track groove 32, and the spherical seat 41b is in sliding contact with the outer diameter portion 38b of the retainer 38 on the joint rear side.

  The rolling bearing 57 is fitted in a circumferential cutout 59 a of a main body 59 of the pedestal 58. In this case, the rolling bearing 57 includes an inner race 61 having a raceway surface 61a formed on the outer diameter surface, an outer race 62 having a raceway surface 62a formed on the inner diameter surface, a raceway surface 61a of the inner race 61, and a raceway surface 62a of the outer race 62. And a rolling element 63 that rolls between them. For this reason, the inner ring 61 is externally fitted to the circumferential cutout 59a, and the outer ring 62 is internally fitted to the short cylindrical portion 56 of the metal spherical seal inner ring 52.

  By the way, notch portions 55a and 55b are provided on the inner end surface and the inner diameter surface of the ring body portion 55 of the metal spherical seal inner ring 52. Therefore, gaps C1 and C2 are formed between the inner ring 61 of the rolling bearing 57 and the bottom surface of the circumferential cutout 59a of the main body 59 of the pedestal 58.

  The metal spherical seal outer ring 54 has a bowl shape and includes a boss 54a and an extension 54b extending from the boss 54a. Then, the inner surfaces of the boss portion 54a and the extension portion 54b form a sealing surface 53 having a concave spherical shape.

  Circumferential recesses 64 and 65 are provided on the outer diameter surface and the inner diameter surface of the boss portion 54a, and a rolling bearing 66 is fitted into the circumferential recess 65 on the inner diameter side. That is, the rolling bearing 66 includes an inner race 67 having a raceway surface 67a formed on an outer diameter surface, an outer race 68 having a raceway surface 68a formed on an inner diameter surface, a raceway surface 67a of the inner race 67, and a raceway surface 68a of the outer race 68. And a rolling element 69 that rolls between them.

  In the rolling bearing 66, the inner ring 67 is fitted to the intermediate portion 40 e of the shaft 40, and the outer ring 68 is fitted to the circumferential recess 65 of the boss 54 a of the metal spherical seal outer ring 54. In this case, the inner ring 67 does not rotate around the shaft axis with respect to the shaft 40, but is slidable in the shaft axis direction. For example, an uneven portion such as a male spline is formed in an intermediate portion 40e of the shaft 40, and an uneven portion such as a female spline which meshes (fits) with the uneven portion of the intermediate portion 40e of the shaft 40 on the inner diameter surface of the inner ring 67 of the rolling bearing 66. What is necessary is just to form a part.

  Further, a shaft-side pedestal 70 interposed between the inner ring 67 and the small-diameter convex portion 40d of the shaft 40 is disposed. The pedestal 70 has an outer diameter side thick ring portion 70a, a thin ring portion 70b extending from the opposite side of the inner diameter surface of the thick ring portion 70a to the inner side, and a joint from the inner diameter end of the thin ring portion 70b. And a pressing portion 70c protruding to the side. In this case, the rolling bearing 66 and the shaft-side pedestal 70 constitute a second bearing structure portion M2 described later.

  The thick ring portion 70a of the shaft-side pedestal 70 is fitted into the circumferential recess 64 on the outer diameter side of the boss portion 54a of the metal spherical seal outer ring 54, and the rolling bearing 66 is pressed by the pressing portion 70c of the shaft-side pedestal 70. When the outer ring 67 is in contact with the outer end surface of the inner ring 67, a gap C3 is generated between the inner end surface 71 of the thick ring portion 70a of the pedestal 70 and the radial end surface 64a of the circumferential recess 64, and the thickness of the pedestal 70 A gap C4 is generated between the inner diameter surface 72 of the ring portion 70a and the circumferential end surface 64b of the circumferential recess 64, and the joint-side end surface 73 of the thin ring portion 70b of the shaft-side pedestal 70 and the metal spherical seal outer ring 54 A gap C5 is formed between the boss 54a and the outer end surface 74 of the boss 54a.

  Further, an elastic member 75 is interposed between the shaft-side pedestal 70 and the outer flange portion 40a of the shaft 40. In this case, the elastic member 75 is a compression spring, and presses the shaft-side pedestal 70 toward the inside of the joint. As described above, when the shaft-side pedestal 70 is pressed toward the inside of the joint, the pressing portion 70c of the shaft-side pedestal 70 presses the outer end surface 67b of the inner ring 67 of the rolling bearing 66 toward the inside of the joint. When the outer end surface 67b of the inner ring 67 of the rolling bearing 66 is pressed toward the inside of the joint, the inner end surface 68b of the outer ring 68 of the rolling bearing 66 presses the rear projection 75 of the circumferential recess 65 toward the inside of the joint. As a result, the sealing surface 53 of the metal spherical seal outer ring 54 presses the sealing surface 51 of the metal spherical seal inner ring 52, and the sealing surfaces 51 and 53 come into close contact with each other.

  For this reason, in the constant velocity universal joint configured as described above, rotation of the metal spherical seal inner ring 52 with the outer joint member 33 on the outer joint member 33 side via the first bearing structure portion M1 is restricted. The metal spherical seal outer ring 54 is mounted on the inner joint member 36 side in a state where rotation with the inner joint member 36 is restricted via the second bearing structure M2. Here, the first bearing structure portion M1 can be configured by the rolling bearing 57 and the pedestal 58, and the second bearing structure portion M2 can be configured by the rolling bearing 66 and the pedestal 70. Therefore, the first bearing structure M1 and the second bearing structure M2 can be stably provided.

  When torque is transmitted by the constant velocity universal joint, the metal spherical seal inner ring 52 and the metal spherical seal outer ring 54 do not rotate. Therefore, the seal portions (the seal surface 51 and the seal surface 53) which are joined by the spherical surface are not rubbed by the rotation, and the life of the seal function can be extended. In addition, since the outer spherical seal ring 54 and the inner spherical seal ring 52 are made of metal, the seal structure can withstand severe use conditions.

  Also, as shown by the imaginary line in FIG. 1, even when the constant velocity universal joint takes an operation angle (for example, 15 °), the metal spherical seal inner ring 52 has the first bearing structure on the outer joint member 33 side. Rotation with the outer joint member 33 is restricted via the portion M1, and rotation of the metal spherical seal outer ring 54 with the inner joint member 36 on the inner joint member 36 side via the second bearing structure portion M2 is regulated. Will be done.

  When the inner joint member 36 is formed by the shaft 40 having the inner ring forming portion 39 in which the track groove 35 into which the ball 37 as the torque transmitting member fits is formed, the shaft 40 and the inner joint member 36 There is no need for spline fitting. For this reason, the assemblability can be improved. If spline fitting is necessary, when the pitch circle of the torque transmitting ball is reduced, the thickness between the spline from the ball groove bottom (track groove bottom) of the inner joint member may be insufficient and strength may not be secured. is there. On the other hand, in the integrated structure, the pitch circle of the torque transmitting ball can be reduced without insufficient strength.

  If the elastic member 75 is provided, the inner ring sliding contact surface (seal surface 53) of the metal spherical seal outer ring 54 and the outer ring sliding contact surface (seal surface 51) of the metal spherical seal inner ring 52 are provided. Closeness can be improved and stable sealing performance can be exhibited.

  As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above embodiments, and various modifications are possible. A sliding type constant velocity universal joint may be used. The fixed constant velocity universal joint may be a bar field type or an undercut free type, and the sliding constant velocity universal joint may be a double offset type or a cross groove type. May also be of the tripod type. In the case of a tripod type, it may be a single roller type or a double roller type. The rolling bearing may be a cylindrical roller bearing, a needle roller bearing, or the like, or may be a sliding bearing. Rolling bearings are optimal because they have less resistance.

33 Outer joint member 35 Track groove 36 Inner joint member 37 Torque transmitting ball 39 Inner ring component 40 Shaft 51 Seal surface 52 Metal spherical seal inner ring 53 Seal surface 54 Metal spherical seal outer ring 57 Rolling bearing 58 Outer joint member side base 66 Rolling Bearing 70 Shaft side pedestal 75 Elastic member M1 First bearing structure M2 Second bearing structure S Seal structure

Claims (5)

An outer joint member having a plurality of track grooves are formed on the inner surface, an inner joint member having a plurality of track grooves are formed on the outer surface, between the track grooves and the track grooves of the inner joint member of the outer joint member A torque transmission member that transmits torque by being interposed therebetween , and the outer joint member includes a mouth portion having a bottom wall, and a constant velocity universal joint in which a shaft is fitted into the mouth portion of the outer joint member. A seal structure for sealing the opening between the mouth and the shaft ,
A metal spherical seal inner ring having a convex spherical seal surface; and a metal spherical seal outer ring having a concave spherical seal surface slidingly in contact with the seal surface of the metal spherical seal inner ring, wherein the metal spherical surface A seal inner ring is mounted on the outer joint member side in a state in which rotation with the outer joint member is restricted via a first bearing structure, and the metal spherical seal outer ring is mounted on the inner joint member side with a (2) A seal structure, wherein the seal structure is mounted in a state where rotation with an inner joint member is restricted via a bearing structure.   The first bearing structure portion includes an outer joint member-side pedestal mounted on the opening of the outer joint member, and a rolling bearing mounted on the outer joint member-side pedestal. The seal structure according to claim 1, wherein the spherical seal inner ring is mounted on the outer joint member side base.   The inner joint member is formed of a shaft having an inner race component having a track groove into which the torque transmitting member is fitted, and the second bearing structure includes a rolling bearing mounted on the shaft. The seal structure according to claim 1, wherein the rolling bearing is provided with the metal spherical seal outer ring. A shaft-side pedestal and an elastic member are disposed on the shaft, and the elastic force of the elastic member is transmitted to the shaft-side pedestal and the bearing of the second shaft portion, so that the metal spherical seal outer ring is provided inside the metal spherical seal. 4. The seal structure according to claim 3, wherein the seal structure is pressed toward the ring so that the seal surface of the metal spherical seal outer ring and the seal surface of the metal spherical seal inner ring are in close contact. An outer joint member having a plurality of track grooves are formed on the inner surface, an inner joint member having a plurality of track grooves are formed on the outer surface, between the track grooves and the track grooves of the inner joint member of the outer joint member A torque transmission member interposed for transmitting torque, and the outer joint member includes a mouth portion having a bottom wall, and a shaft is fitted into the mouth portion of the outer joint member. ,
The constant velocity universal joint, wherein an opening of the outer joint member is sealed in the seal structure according to any one of claims 1 to 4.

Images