JP4869854B2 - Seal structure - Google Patents

Description

  The present invention relates to a seal structure applicable to a sliding type constant velocity universal joint that expands and contracts greatly as a power transmission drive shaft of a general industrial machine or a vehicle.

  Constant velocity universal joints can be broadly divided into fixed types that allow only angular displacement between two axes, and sliding types that allow angular displacement and axial displacement, depending on the use conditions and applications. Selected. Representative examples of the fixed type include a Zepper type constant velocity universal joint, and examples of the sliding type include a double offset type constant velocity universal joint, a tripod type constant velocity universal joint, and the like. Of the sliding types, tripod type constant velocity universal joints use rollers as torque transmission members, and others use balls as torque transmission members.

  For example, as shown in FIG. 6, a double offset type constant velocity universal joint includes an outer joint member (outer ring) 3 in which a plurality of linear track grooves 2 are formed in an axial direction on a cylindrical inner diameter surface 1, and a spherical shape. An inner joint member (inner ring) 6 in which a plurality of (same number of track grooves 2) linear track grooves 5 are formed in the outer diameter surface 4 in the axial direction, and the track groove 2 and inner joint member 6 of the outer joint member 3. A torque transmission ball 7 disposed on a ball track formed in cooperation with the track groove 5 and a cage (cage) 8 for holding the torque transmission ball 7.

  The spherical center O1 of the outer diameter surface 8a of the cage 8 and the spherical center O2 of the inner diameter surface 8b are offset from the pocket center O to the opposite side in the axial direction, respectively.

  A shaft 10 is fitted into the inner joint member 6. That is, the spline portion 11 is formed on the inner diameter surface of the center hole of the inner joint member 6, and the spline portion 9 of the shaft 10 is fitted to the spline portion 11.

  A boot 15 is attached to the opening of the outer joint member 3. The boot 15 includes a large diameter portion 15a, a small diameter portion 15b, and a bellows portion 15c between the large diameter portion 15a and the small diameter portion 15b. The large diameter portion 15 a is fitted to the outer diameter surface on the opening side of the outer ring 3, and the small diameter portion 15 b is fitted to the boot mounting portion 16 of the shaft 10.

  In this case, a circumferential groove 17 is formed on the outer peripheral surface of the large-diameter portion 15a, and a boot band 18 is fastened to the circumferential groove 17 so that the large-diameter portion 15a and the outer joint member 3 are integrated. . Further, a concave groove 19 is formed in the boot mounting portion 16 of the shaft, and a small diameter portion 15 b is fitted in the circumferential concave groove 19. A circumferential groove 20 is formed on the outer peripheral surface of the small diameter portion 15b, and the boot band 18 is fastened to the circumferential groove 20 so that the small diameter portion 15b and the shaft 10 are integrated.

  When this type of joint transmits rotational torque while taking an operating angle, the cage 8 rotates to the position of the torque transmission ball 7 that moves on the ball track in accordance with the inclination of the inner joint member 6, thereby transmitting torque. The ball 7 is held within the angle bisector of the operating angle. Further, when the outer joint member 3 and the inner joint member 6 move relative to each other in the axial direction, slip occurs between the outer diameter surface of the cage 8 and the inner diameter surface 1 of the outer joint member, and smooth axial movement (plan Zing) is possible.

  As described above, the bellows type flexible boot is applied as the boot of the sliding type constant velocity universal joint, and the same applies to the boot of the tripod type sliding type constant velocity universal joint (Patent Document 1). Further, a sealing device including a metal adapter and a boot has been proposed (Patent Document 2). This sealing device is attached to a cross groove type constant velocity universal joint as shown in FIG.

  The constant velocity universal joint shown in FIG. 7 has linear track grooves 25, 22 inclined on the outer peripheral surface 24 of the inner ring 26 and the inner peripheral surface 21 of the outer ring 23 in directions opposite to each other in the axial direction. Formed in the axial direction, balls 27 are incorporated at the intersections of both track grooves 25, 22, and these balls 27 are held by a cage 28 disposed between the outer peripheral surface 24 of the inner ring 26 and the inner peripheral surface 21 of the outer ring 23. Is. A shaft 30 is fitted into the inner ring 26. That is, the spline portion 31 is formed on the inner diameter surface of the center hole of the inner ring 26, and the spline portion 29 of the shaft 10 is fitted to the spline portion 31.

  The sealing device includes a metal adapter 33 attached to the outer ring 23, and a boot 34 attached to the adapter 33 and the shaft 30. The metal adapter 33 includes an outer ring fitting portion 33a and a cylindrical main body portion 33b. The outer ring fitting portion 33a includes a large-diameter short cylindrical portion 35 and a radial wall 36 extending from the short cylindrical portion 35 in the inner diameter direction. The short cylindrical portion 35 is fitted on the outer diameter surface on the one end surface 23a side of the outer ring 23, and the fastener 37 made of a bolt member in a state where the radial wall 36 is in contact with the one end surface 23a of the outer ring 23. The metal adapter 33 is fixed to the outer ring 23.

  In this case, the flange member 38 is fixed to the other end surface 23 b side of the outer ring 23 via the fastener 37. That is, the flange member 38 is formed with a recess 39 into which the other end surface 23 b side of the outer ring 23 is fitted, and is provided with a screw hole 40. The other end surface 23 b side of the outer ring 23 is fitted in the recess 39, and the bolt member as the fastener 37 is inserted into the through hole 41 provided in the radial wall 36 of the metal adapter 33 and the through hole 42 of the outer ring 23. The metal adapter 33 and the flange member 38 can be attached to the outer ring 23 by being screwed into the screw hole 40 via.

The boot 34 includes a large diameter portion 34a, a small diameter portion 34b, and a bent portion 34c that connects the large diameter portion 34a and the small diameter portion 34b. Then, the large diameter portion 34 a of the boot 34 is fixed to the metal adapter 33 by crimping the opening end portion of the main body portion 33 b of the metal adapter 33. Further, the small-diameter portion 34b of the boot 34 is fixed to the shaft 30 by externally fitting the small-diameter portion 34b of the boot 34 to the shaft 30 and fastening the boot band 45 fitted in the concave groove 43 of the small-diameter portion 34b. The
JP 2000-283175 A JP 2003-56590 A

  When the boot 15 as shown in FIG. 6 is used under a high rotational speed condition, the lubricating grease filled in the joint inside the bellows portion 15c is unevenly distributed and expands by the centrifugal force during rotation. When the rotational speed exceeds a certain value, the bellows portion 15c abnormally expands and deforms. If it expands and deforms in this way, there is a possibility that it will be damaged by interference with the peripheral part, or in some cases it cannot withstand the deformation and burst.

  Therefore, as a device corresponding to high-speed rotation, a sealing device including a metal adapter 33 and a boot 34 as shown in FIG. 7 has been proposed. However, even if such a metal adapter 33 is used or a metal adapter 33 as shown in FIG. 6 is not used, the small diameter portions 15b and 34b of the boots 15 and 34 are connected to the joint. The shafts 10 and 30 are clamped at a position having a certain distance from the center. Therefore, as a constant velocity universal joint assembly (a constant velocity universal joint in a state where the boot is mounted), when the space in the longitudinal direction (axial direction) is limited, the boots 15 and 34 shown in FIGS. Is not applicable.

  In particular, when the amount of expansion / contraction between the inner ring and the outer ring exceeds, for example, 100 mm, there is a problem that the bellows portion 15c and the bent portion 34c cannot cope.

  In view of the above problems, the present invention is excellent in high-speed rotation performance (performance capable of high-speed rotation), and can also follow large expansion and contraction in the axial direction between the inner member (inner ring) and the outer member (outer ring). Provide a seal structure with less restrictions on installation space.

The seal structure of the present invention is a seal structure that closes a gap between an inner member that rotates around an axis and an outer member that rotates around the axis and is capable of relative displacement in the axial direction of the inner member. there, a large diameter portion mounted on the outer member, and a small diameter portion which is mounted in front Symbol inner member consists of a cone section connecting the large diameter portion and a small diameter portion, the bellows portion in the cone portion an elastic deformable tubular boot having no, this boot via the short cylindrical portion of the slide-in state in which the small diameter portion is housed state within the outer member the large-diameter portion is provided on the outer member with folded back from the inner diameter side to the small diameter portion, the small diameter portion is the small-diameter portion in a slide-out condition to be exposed state from the outer member is folded back to the large diameter portion from the outer diameter side through a spacer for preventing buckling, The axial stroke amount between the inner member and the outer member is Almost twice the axial length between the large diameter portion and a small diameter portion of the boot in the derived state, is intended to follow the axial direction of the relative displacement between the inner and outer members.

  According to the seal structure of the present invention, in the boot, the large diameter portion is folded from the inner diameter side to the small diameter portion side in a slide-in state where the small diameter portion is housed in the outer member, and the small diameter portion is exposed from the outer member. In the slide-out state, the small diameter portion is folded from the outer diameter side to the large diameter portion side. That is, the displacement difference between the slide-in state and the slide-out state is approximately twice the length between the small diameter portion and the large diameter portion. Moreover, it is not necessary to provide a conventional bellows part between the small diameter part and the large diameter part, despite following such a large displacement.

In the slide-in state, the large-diameter portion is folded back from the inner diameter side to the smaller-diameter portion side through the short cylindrical portion, and a buckling prevention spacer is disposed on the inner diameter side of the boot folded portion formed in the slide-out state. Can do. For this reason, buckling of the boot folded portion can be prevented on the large diameter portion side and the small diameter portion side, and damage to the boot in the boot folded portion can be prevented.

  As the seal structure, the inner member is an inner joint member of a constant velocity universal joint having a track groove formed on the outer diameter surface, and the outer member is an outer joint member of the constant velocity universal joint formed with a track groove on the inner diameter surface. As a constant velocity universal joint.

  As a sealing structure, the inner member is a first rotating body of a gear coupling having an internal gear, and the outer member is a second rotating body of a gear coupling having an external gear meshing with the internal gear. Can be used.

  As the seal structure, the inner member can be used as an inner ring of the ball spline, and the outer member can be used as an outer ring of the ball spline in the ball spline.

  In the seal structure of the present invention, the difference in displacement between the slide-in state and the slide-out state is about twice the length between the small diameter portion and the large diameter portion, and the axial direction relative to the inner member and the outer member is Can follow a large displacement. In addition, since there is no need to provide a bellows portion as in the prior art between the small-diameter portion and the large-diameter portion, it is possible to avoid the expansion of the boot due to a lubricant such as a lubricating grease during rotation, and to achieve high-speed rotation resistance. Excellent. Furthermore, in the slide-in state, the small-diameter portion is housed in the outer member, and the overall length of the boot can be shortened compared to a conventional one (a boot having a bellows portion or a bent portion) having the same expansion / contraction amount. . For this reason, it can arrange | position in a site | part with restrictions in the space of an axial direction like a gauge conversion trolley | bogie.

  Buckling of the boot folded portion formed in the slide-out state can be prevented by the buckling prevention spacer, and damage to the boot at the boot folded portion can be prevented. Thereby, it becomes what was excellent in durability and exhibits the stable sealing effect over a long period of time.

  The seal structure of the present invention can be used in various devices and mechanisms such as constant velocity universal joints, gear couplings, and ball splines. In addition, when used in these devices, mechanisms, etc., it is excellent in high-speed rotation resistance and durability, and exhibits an excellent sealing effect stably over a long period of time.

  An embodiment of a constant velocity universal joint according to the present invention will be described with reference to FIGS.

  FIG. 1 shows a main part of a gauge conversion carriage using the seal structure according to the present invention. As shown in FIG. 3, the gauge conversion carriage 50 includes a track narrow gauge section 52 including a pair of rails 51 and 51 arranged at a narrow interval, and a pair of rails 53 and 53 arranged at a standard interval. It is a cart that can travel with the standard gauge section 54. Between the narrow gauge section 52 and the standard gauge section 54, a gauge conversion section 56 including connecting rails (guide rails) 55 and 55 is provided.

  That is, the bogie 50 is such that the distance between the opposed wheels 57 and 57 (see FIG. 1) is displaced. In the narrow gauge section 52, the wheels 57 and 57 correspond to the rail distance of the section 52, and the rail 51 , 51. Further, in the standard gauge section 54, the wheels 57 and 57 travel on the rails 53 and 53 corresponding to the rail interval of the section 54. From the narrow gauge section 52 to the standard gauge section 54, or from the standard gauge section 54 to the narrow gauge section 52, the wheels 57, 57 correspond to the distance between the connecting rails 55, 55 of the gauge conversion section 56, and on the connecting rails 55, 55. Drive on.

  For this reason, the cart 50 is provided with a wheel position changing mechanism M as shown in FIG. The wheel position changing mechanism M includes a first constant velocity universal joint 60A and a second constant velocity universal joint 60B.

  The first constant velocity universal joint 60A includes an outer ring 63 (63A) as an outer member in which a plurality of track grooves 62 are formed in the axial direction on the inner diameter surface, and a plurality (the same number as the track grooves 62) on the outer diameter surface. Torque transmission disposed on a ball track formed by the inner ring 66 (66A) as an inner member in which the track groove 65 is formed in the axial direction, the track groove 62 of the outer ring 63A, and the track groove 65 of the inner ring 66 are formed in cooperation. A ball 67 (67A) and a cage (cage) 68 (68A) for holding the torque transmission ball 67 are provided.

  The inner ring 66 </ b> A is connected to a sleeve member 71 that is fitted on a shaft (ring shaft) 70, and the wheel 57 is connected to the sleeve member 71. That is, when the sleeve member 71 reciprocates in the axial direction with respect to the shaft 70, the wheel 57 reciprocates along the shaft axis. At this time, the inner ring 66A also reciprocates along the shaft axis.

  The opening between the inner ring 66 </ b> A and the outer ring 63 </ b> A is closed with a seal structure having a boot 72. As shown in FIG. 2, the boot 72 includes a large diameter portion 72a, a small diameter portion 72b, and a cone portion 72c that connects the large diameter portion 72a and the small diameter portion 72b. The boot material may be a thermoplastic elastomer such as ester, olefin, urethane, amide, or styrene, or rubber such as chloroprene.

  In this case, the adapter 73 is fixed to the wheel side end surface of the outer ring 63 </ b> A via the bolt member 74, and the large diameter portion 72 a of the boot 72 is attached to the adapter 73. That is, the adapter 73 includes a main body portion 73a formed of a flat ring body fixed in contact with the wheel-side end surface of the outer ring 63A, and a short cylindrical portion 73b extending from the main body portion 73a to the wheel side along the axial direction. Prepare.

  Further, a circumferential concave groove 75 is formed on the inner diameter surface of the large diameter portion 72a of the boot 72, and as shown by the phantom line in FIG. 2, the large diameter portion 72a is folded back so that the outer diameter surface 76 becomes the adapter. 73 is superposed on the outer diameter surface 77 of the short cylindrical portion 73b. That is, the circumferential groove 75 on the inner diameter surface of the large diameter portion 72a is disposed on the outer diameter side, and in this state, the boot band 78 is fitted and fastened to the circumferential groove 75. As a result, the large-diameter portion 72a of the boot 72 is mounted on the outer ring 63A side. At this time, a thick portion 107 is formed at the distal end portion of the short cylindrical portion 73b, and a bulging portion 107a protruding toward the outer diameter side is provided at the distal end edge of the thick portion 107. For this reason, the large diameter portion 72a side of the boot 72 is folded back through the thick portion 107 of the short cylindrical portion 73b. In this state, the boot band 78 is fitted into the circumferential groove 75 and fastened. As a result, the large diameter portion 72a of the boot 72 is mounted on the outer ring 63A side.

  A circumferential groove 81 is provided in the vicinity of the wheel side end of the track groove 65 on the outer diameter surface of the inner ring 66 </ b> A, and a small diameter portion 72 b of the boot 72 is fitted on the circumferential groove 81. The boot band 78 is fitted and fastened to the circumferential groove 80 formed on the outer diameter surface of the small diameter portion 72b. As a result, the small diameter portion 72b of the boot 72 is mounted on the inner ring 66A side.

The first constant velocity universal joint 60A of the configured wheel position changing mechanism M as described above, slide-in state the small diameter portion 72b of the boot 72 is housed state within the outer ring 63A of the outer member (in Fig. 1 state) shown in the upper half, a small diameter portion 72b is displaced in the slide-out state to be exposed state from the outer ring 63A (the state shown in the lower half of Figure 1).

  In the slide-in state shown in the upper half of FIG. 1, the large-diameter portion 72a is folded back from the inner diameter side to the small-diameter portion 72b side as shown by the phantom line in FIG. In the slide-out state shown in the lower half of FIG. 1, the small diameter portion 72b is folded back from the outer diameter side to the large diameter portion 72a side. That is, the boot 72 follows the relative axial displacement of the inner ring 66A and the outer ring 63A. Note that the small diameter portion 72b is not folded back in the slide-in state, and the large diameter portion 72a is not folded back in the slide-out state.

  The second constant velocity universal joint 60B includes an inner ring 66B, an outer ring 63B, a ball 67B fitted to a ball track between the inner ring 66B and the outer ring 63B, and a cage 68B that holds the ball 67B. . A fixing member 84 is disposed on the first constant velocity universal joint 60A side of the outer ring 63B, and a bolt member 85 inserted through the fixing member 84 and the outer ring 63B is screwed to the wheel 57, whereby the outer ring 63B is moved to the wheel 57. It is fixed to. The fixing member 84 includes a flat ring body 84a and a short cylindrical portion 84b extending from the inner diameter end of the flat ring body 84a toward the first constant velocity universal joint 60A. The flat ring body 84a is a wheel 57. The seal member 83 is interposed between the short cylinder portion 84b and the inner ring 66B.

  In the seal structure of the present invention, the boot 72 has the large-diameter portion 72a folded back from the inner diameter side to the small-diameter portion side in a slide-in state where the small-diameter portion 72b is housed in the outer ring 63, and the small-diameter portion 72b is separated from the outer ring 63A. The small diameter portion 72b is folded from the outer diameter side to the large diameter portion side in the exposed slide-out state. That is, the displacement difference between the slide-in state and the slide-out state is approximately twice the length between the small diameter portion 72b and the large diameter portion 72a. For this reason, it is possible to follow a relatively large axial displacement between the inner ring 66A and the outer ring 63A.

  Moreover, it is not necessary to provide a conventional bellows portion between the small diameter portion 72b and the large diameter portion 72a in spite of following such a large displacement. The expansion of the boot 72 can be avoided, and the high-speed rotation resistance is excellent. Furthermore, in the slide-in state, the small-diameter portion is housed in the outer member, and the overall length of the boot can be shortened compared to a conventional one (a boot having a bellows portion or a bent portion) having the same expansion / contraction amount. . For this reason, it can arrange | position in the site | part with restrictions in the space of an axial direction like the gauge conversion trolley | bogie etc. which are shown in FIG.

  By the way, in an inter-gauge conversion truck that is required to mutually enter a standard gauge of 1435 mm and a narrow gauge of 1069 mm, for example, the first constant velocity universal joint 60A has an outer ring outer diameter of about 300 mm and an inner ring inner diameter of 230 mm. There is a cross groove type having 18 balls. And this constant velocity universal joint is located in the cylinder of a large gear, and expansion and contraction of 180 mm or more is allowed in a limited space in the longitudinal direction (axial direction). Moreover, if the carriage is a Shinkansen, high-speed rotation is required that exceeds the rotational speed of 2000 rpm when the speed is 300 km / h. Thus, even if it rotates at high speed, the seal structure of the present invention can withstand this high-speed rotation because it is configured as described above.

In the slide-out state, the small-diameter portion 72b is folded back, and as shown in FIG. 4, a buckling prevention spacer 82 is disposed in the vicinity of the small-diameter portion 72b of the boot 72, that is, on the inner diameter side of the boot folded portion . . The buckling prevention spacer 82 can be configured by an O-ring 82 a that is fitted around the small diameter portion 72 b of the boot 72.

This prevents damage to the boot in the boot folded portion, becomes excellent in durability, it exhibits stable sealing effect over a long period of time.

  Next, FIG. 5 shows a constant velocity universal joint to which a seal structure according to the present invention is applied. This is a double offset type constant velocity universal joint, and a plurality of linear track grooves 92 are axially formed on a cylindrical inner surface 91. An outer joint member 93 formed on the outer surface 94, an inner joint member 96 formed with a plurality of (same number of track grooves 92) linear track grooves 95 in the axial direction on a spherical outer diameter surface 94, and an outer joint member 93. The track groove 92 of the inner joint member 96 and the track groove 95 of the inner joint member 96 are provided with a torque transmission ball 97 disposed on a ball track, and a cage 98 that holds the torque transmission ball 97. .

  The spherical center O1 of the outer diameter surface 98a of the cage 98 and the spherical center O2 of the inner diameter surface 98b are offset from the pocket center O to the opposite side in the axial direction, respectively.

  In addition, the shaft 100 is fitted into the inner joint member 96. That is, the spline portion 101 is formed on the inner diameter surface of the center hole of the inner joint member 96, and the spline portion 99 of the shaft 100 is fitted to the spline portion 101.

  The gap between the outer joint member 93 and the shaft 100 is closed by the seal structure according to the present invention. The seal structure in this case includes a metal adapter 102 attached to the outer joint member 93 and a boot 72 attached to the adapter 102 and the shaft 100. The boot 72 uses the boot 72 shown in FIGS.

  The metal adapter 102 includes a disk part 102a and a cylindrical part 102b in the axial direction from the inner diameter end of the disk part 102a. A concave portion 103 is provided on the end surface of the disk portion 102 a on the side opposite to the cylindrical portion, and the opening end portion of the outer joint member 93 is fitted in the concave portion 103. Then, by screwing the bolt member 106 into the screw hole 105 formed in the opening end surface of the outer joint member 93 through the through hole 104 provided in the disk portion 102a, the metal adapter 102 is attached to the outer joint member 93. It is attached to.

  Further, a thick portion 107 is formed at the tip of the cylindrical portion 102b, like the short cylindrical portion 73b of the adapter 73 shown in FIG. 2, and the tip edge of the thick portion 107 protrudes to the outer diameter side. A bulging portion 107a is provided. For this reason, the large diameter portion 72a side of the boot 72 is folded back through the thick portion 107 of the cylindrical portion 102b, and the outer diameter surface 76 is overlapped with the outer diameter surface 108 of the cylindrical portion 102b. In this state, the boot band 78 is fitted into the circumferential groove 75 and fastened. As a result, the large diameter portion 72a of the boot 72 is mounted on the outer joint member 93 side.

  A circumferential concave groove 109 is provided in the vicinity of the spline portion 99 of the shaft 100, and a small diameter portion 72 b of the boot 72 is fitted on the circumferential concave groove 109, and the circumferential concave groove formed in the small diameter portion 72 b of the boot 72 is formed. The boot band 78 is fitted into the groove 80 and fastened. As a result, the small diameter portion 72b of the boot 72 is attached to the inner joint member 96 side.

  Even in this constant velocity universal joint, the boot 72 has the small diameter portion 72b folded back from the inner diameter side to the small diameter portion 72b side in a slide-in state in which the small diameter portion 72b is housed in the outer joint member. In a slide-out state in which 72b is exposed from the outer joint member, the small diameter portion 72b is folded from the outer diameter side to the large diameter portion 72a side.

  For this reason, it is possible to follow a relatively large displacement between the inner joint member 96 and the outer joint member 93 in the axial direction. Moreover, it is not necessary to provide a conventional bellows portion between the small diameter portion 72b and the large diameter portion 72a in spite of following such a large displacement. The expansion of the boot 72 can be avoided, and the high-speed rotation resistance is excellent.

  The seal structure of the present invention can also be applied to gear couplings, ball splines, and the like. The gear coupling performs power transmission between the first rotating body and the second rotating body by meshing between an internal gear provided on the first rotating body and an external gear provided on the second rotating body. . Then, when the first rotating body and the second rotating body are relatively displaced in the axial direction, the seal structure of the present invention is used for the sealing structure that closes the gap between the first rotating body and the second rotating body. can do.

  A ball spline has a large number of balls interposed between an outer ring (outer cylinder) and an inner ring (inner cylinder) that are coaxial with each other, and the outer cylinder and the inner cylinder slide in the axial direction via the balls. Power can be transmitted. And the seal structure of this invention can be used for the seal structure which plugs up the clearance gap between an outer cylinder and an inner cylinder.

  As described above, the seal of the present invention can be used in various devices and mechanisms such as a constant velocity universal joint, a gear coupling, and a ball spline. In addition, when used in these devices, mechanisms, etc., it is excellent in high-speed rotation resistance and durability, and exhibits an excellent sealing effect stably over a long period of time.

  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 a constant velocity universal joint, it slides in the axial direction of the outer joint member. The present invention can be applied to a sliding constant velocity universal joint provided with a mechanism to perform the above, and can be applied to various sliding constant velocity universal joints such as a tripod type and a cross groove type other than the double offset type.

  As the buckling prevention spacer, other than the O-ring, a square ring, a D ring, a T ring, an X ring, and the like can be used. In short, it suffices if the folded portion is bent too much to prevent a decrease in life. These materials may be any materials that can cope with the environment in which the seal structure is used, and various materials such as resin and rubber can be used.

It is principal part sectional drawing of the gauge conversion trolley | bogie using the seal structure which shows embodiment of this invention. It is sectional drawing of the boot of the said seal structure. It is a simple top view of the rail which the said gauge change cart runs. It is a fragmentary cross-sectional view before Ki軌 between conversion carriage. It is sectional drawing of the constant velocity universal joint which uses the said seal structure. It is sectional drawing of the constant velocity universal joint using the conventional seal structure. It is sectional drawing of the other constant velocity universal joint which uses the conventional seal structure.

Explanation of symbols

72 Boot 72a Large diameter portion 72b Small diameter portion 82 Buckling prevention spacer 91 Inner surface 92 Track groove 93 Outer joint member 94 Outer surface 95 Track groove 96 Inner joint member

Claims (5)

A seal structure that closes a gap between an inner member that rotates about an axis and an outer member that rotates about the axis and is capable of relative displacement in the axial direction of the inner member;
It consists of a large diameter portion mounted on the outer member, and a small diameter portion which is mounted in front Symbol inner member, a cone section which connects the large diameter portion and a small diameter portion, no bellows portion to the cone portion an elastic deformable tubular boots, the boots from the inner diameter side through the short cylindrical portion of the slide-in state in which the small diameter portion is housed state within the outer member the large-diameter portion is provided on the outer member together are folded into the small diameter portion, the small diameter portion is the small-diameter portion in a slide-out condition to be exposed state from the outer member is folded back to the large diameter portion from the outer diameter side through a spacer for preventing buckling, an inner member The axial stroke amount with the outer member is almost twice the axial length between the large diameter portion and the small diameter portion of the boot in the free state, so that the axial relative of the inner member and the outer member is relative. A seal structure that follows displacement. 2. The seal structure according to claim 1, wherein the buckling prevention spacer includes a ring body disposed on an inner diameter side of a boot folded portion formed in a slide-out state.   The inner member is an inner joint member of a constant velocity universal joint in which a track groove is formed on an outer diameter surface, and the outer member is an outer joint member of a constant velocity universal joint in which a track groove is formed on an inner diameter surface. The seal structure according to claim 1 or 2, wherein   The inner member is a first rotating body of a gear coupling having an internal gear, and the outer member is a second rotating body of a gear coupling having an external gear meshing with the internal gear. The seal structure according to claim 1 or 2.   The seal structure according to claim 1 or 2, wherein the inner member is an inner ring of a ball spline and the outer member is an outer ring of a ball spline.

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