JP4012186B2 - Joint boots - Google Patents

Description

  The present invention relates to a bellows-shaped joint boot mainly used for an automobile triport type constant velocity joint or the like.

  A triport type joint is known as one of constant velocity joints used for vehicle drive shafts and the like.

  For example, as shown in FIGS. 6 and 7, the triport type constant velocity joint has three trunnions 3 each having a roller 2 protruding in a direction perpendicular to the axis on one shaft 1 on the input side and the output side. And the outer case 6 provided at the end of the other shaft 5. The outer case 6 has three sliding grooves 6 a in the axial direction corresponding to the tripart 4 on the inner periphery thereof. The constant velocity joint is capable of transmitting rotational torque while allowing the shafts 1 and 5 to be angled by fitting the roller 2 of the triport 4 with the sliding groove 6a so as to be slidable in the axial direction. It is configured.

  In such a constant velocity joint, in order to prevent dust and foreign matter from entering the joint, or to keep the sealed grease, generally, the portion of the shaft 1 on the side of the triport 4 from the outer case 6 is used. A joint boot 100 having a bellows shape that can be appropriately expanded and contracted and bent so as to cover is mounted. The joint boot 100 is formed as a large-diameter side attachment portion 101 having one end portion in the axial direction fitted on the outer periphery of the outer case 6 and fixed by a fastening member 7 such as a ring-shaped band, and the other end portion is the tripart 4. It is formed as a small-diameter side mounting portion 102 that is fixed to the outer periphery of the side shaft 1 by a fastening member 8 such as a ring-shaped band, and the both 101 and 102 are integrally connected by a bellows portion 103.

  As shown in FIG. 7, the outer case 6 is provided with three concave portions 6 b arranged in the circumferential direction on the outer periphery corresponding to the arrangement of the sliding grooves 6 a on the inner periphery. The outer peripheral shape is formed in a non-circular shape having an uneven shape in the circumferential direction. Therefore, the large-diameter side attachment portion 101 of the joint boot 100 attached to the outer case 6 has a noncircular shape whose inner peripheral shape corresponds to the outer peripheral shape of the outer case 6. That is, the inner periphery of the large-diameter side mounting portion 101 is formed to project inwardly at three locations in the circumferential direction corresponding to the concave portion 6 b of the outer case 6.

When such an inwardly projecting portion 104 of the large diameter side mounting portion 101 is a solid thick portion as shown in FIG. 6, a thick portion and a thin portion in the circumferential direction of the large diameter side mounting portion 101. Are alternately formed, and there is a problem that it is difficult to ensure sufficient sealing performance with the outer case 6. As means for solving this problem, the following configurations are disclosed in Patent Documents 1 and 2 below. That is, in Patent Document 1, the large-diameter side mounting portion has a plurality of arc-shaped wall portions arranged in a common cylindrical surface, and an overhang formed in an inwardly curved manner between the arc-shaped wall portions. There is disclosed a configuration in which a wall portion is provided, and support wall portions that elastically support the wall portion are provided on the outer surface of the overhanging wall portion at intervals in the circumferential direction. In addition, a configuration is disclosed in which a plurality of axially extending support wall portions provided at intervals in the circumferential direction are reinforced with support wall portions extending in the circumferential direction. Patent Document 2 discloses a configuration in which a groove (slot) extending in the circumferential direction is provided on the outer peripheral surface of the inwardly projecting portion of the large-diameter side mounting portion.
European Patent Application No. 0915264 (especially FIG. 3) JP 2002-122237 A

  Patent Document 1 discloses that the support wall portion extending in the circumferential direction is provided on the outer surface of the overhanging wall portion of the large-diameter side attachment portion as described above, but is provided on the inner peripheral surface of the large-diameter side attachment portion. The relationship with the seal ridges is silent. Further, Patent Document 2 describes that two sealing protrusions are provided on the inner peripheral surface of the large-diameter side mounting portion, but the positions of the sealing protrusions and the groove extending in the circumferential direction are described. The relationship is not clear.

  In the overhanging portion of the large-diameter side mounting portion that is externally fitted and fixed to the non-circular outer case as described above, the sealing performance is improved by changing the solid shape to the above-described hollow shape. However, there are cases where further improvement in sealing performance is required. In such a case, it is difficult to meet the demand for high sealing performance only by the structure on the outer surface side of the overhanging wall portion, and the relationship with the sealing protrusions provided on the inner side surface of the overhanging wall portion becomes important.

  The present invention has been made in view of the above points, and in joint boots attached to a non-circular outer case like a triport type constant velocity joint, the sealing performance is higher than before. It aims at providing what can demonstrate.

The joint boot according to the present invention includes a large-diameter side mounting portion that is externally fixed to the outer case having a plurality of concave portions in the circumferential direction using a fastening member, and a small-diameter side mounting portion that is attached to the shaft. A joint boot comprising a bellows part integrally connecting the two, wherein the large-diameter side attachment part includes a plurality of arcuate wall parts arranged at intervals in the circumferential direction within a common cylindrical surface; between the arc-like wall portion is curved in the overhang formed radially inward, and it and a projecting wall portion having the same thickness as the arcuate wall portion, the peripheral inside surface of the projecting wall portion A plurality of sealing ridges extending in the direction are provided at intervals in the axial direction, and a supporting wall portion extending in the circumferential direction for supporting the outer surface on the outer surface of the projecting wall portion is provided on the plurality of sealing ridges . each seal so as to correspond to each Match the arrangement position in the ridge and boots axial direction in which provided with a plurality.

  In the joint boot of the present invention, the inwardly projecting portion of the large-diameter side mounting portion that is fitted into the concave portion of the outer case has a curved projecting wall portion and a support wall provided on the outer surface thereof Compared with the case where the overhanging part is formed with a solid thick part, it is possible to prevent the occurrence of sink marks due to shrinkage after molding, and the thick part and the thin part. The unevenness of the tightening force can be reduced. Therefore, moldability and sealability can be improved.

  Further, particularly in the present invention, the circumferentially extending support wall portion that supports the outer surface of the overhanging wall portion coincides with the sealing protrusion provided on the inner surface of the overhanging wall portion, that is, the overhanging portion. Since the support wall portion is provided so as to overlap the sealing ridge through the wall portion, the tightening force by the tightening member is surely exerted on the sealing ridge through the support wall portion. High sealing performance can be exhibited.

  In the joint boot of the present invention, it is preferable that the outer edge of the support wall portion is formed along a cylindrical surface common to the arc-shaped wall portion, in order to ensure stable tightening performance by the tightening member.

In the joint boot of the present invention, preferably the connecting wall extending boot axis connecting both between adjacent support wall portion is provided with a plurality at intervals in the circumferential direction. Thereby, it is possible to prevent the support wall portion extending in the circumferential direction from falling during the tightening by the tightening member, and to more reliably apply the tightening force by the tightening member to the sealing protrusion.

  ADVANTAGE OF THE INVENTION According to this invention, in a joint boot attached to the outer case of a non-circular outer periphery shape like a triport type constant velocity joint, a high sealing performance can be exhibited more than before.

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

  FIG. 1 is a half cross-sectional half side view of a joint boot 10 according to an embodiment of the present invention, and FIG. 2 is a front view of its large diameter side. The joint boot 10 is a thermoplastic elastomer resin boot to be mounted on the above-described triport type constant velocity joint for an automobile shown in FIGS. 6 and 7, and includes a small diameter side mounting portion 12 on one end side and the small diameter side. A large-diameter side attachment portion 14 on the other end side that is coaxially disposed apart from the attachment portion 12, and a hollow bellows portion 16 that integrally connects the small-diameter side attachment portion 12 and the large-diameter side attachment portion 14. And is integrally formed by a known molding method such as injection blow molding.

  The small-diameter side mounting portion 12 has a short cylindrical shape that is fitted and fixed to the shaft 1 on the triport 4 side, and a fixing concave portion 18 that extends in the circumferential direction for receiving the ring-shaped fastening member 8 on the outer peripheral surface. Is provided. The large-diameter side mounting portion 14 has a substantially short cylindrical shape that is fitted and fixed to the outer case 6, and is arranged coaxially with the small-diameter side mounting portion 12, that is, with a common center line L. . The bellows portion 16 is a bellows body having a circular cross section with a difference in diameter at both ends, and forms a grease filled space therein. The bellows portion 16 is formed in a tapered shape so as to be sequentially reduced from the large diameter side mounting portion 14 to the small diameter side mounting portion 12.

  As shown in FIG. 2, the outer diameter of the large-diameter-side mounting portion 14 has a circular shape. On the other hand, the inner peripheral shape has a plurality (three in this embodiment) of concave portions 6 b in the circumferential direction. Corresponding to the outer peripheral shape of the outer case 6 arranged uniformly, a non-circular shape projecting inwardly into a curved surface is formed at a plurality of locations in the circumferential direction (three locations in this embodiment).

  Specifically, the large-diameter side attachment portion 14 is fitted into the three arc-shaped wall portions 22, 22, 22 disposed on the arc-shaped outer peripheral surface of the outer case 6 and the concave portion 6 b of the outer case 6. Three projecting wall portions 24, 24, 24 are provided, and these are alternately arranged in the circumferential direction. The arc-shaped wall portions 22 are arranged at equal intervals in the circumferential direction within a common cylindrical surface with the center line L as an axis, and have a substantially constant thickness in the circumferential direction. The overhanging wall portion 24 is formed between the adjacent arcuate wall portions 22 and 22 so as to protrude radially inwardly therefrom, has a substantially constant thickness in the circumferential direction, and has a circular shape. It has substantially the same thickness as the arcuate wall portion 22.

  On the inner peripheral surface of the large-diameter side mounting portion 14, a sealing protrusion 26 extending over the entire circumferential direction is provided. A plurality of sealing ridges 26 (two in this embodiment) are provided in parallel with each other at intervals in the axial direction.

  The outer surface of the arc-shaped wall portion 22 is provided with two circumferentially extending ridges 28, 28 that are spaced apart in the axial direction and extend in the circumferential direction, and a ring-shaped fastening member therebetween. 7 is a fixing recess 20 extending in the circumferential direction for receiving 7.

  A support wall portion 30 extending in the circumferential direction for supporting the overhanging wall portion with respect to the fastening member 7 is provided on the outer surface of the overhanging wall portion 24. As shown in FIG. 3, in this embodiment, two supporting wall portions 30 are provided in parallel to each other at an axial interval, and the inner surface of the overhanging wall portion 24 is shown in FIGS. Are provided so as to correspond to the two sealing protrusions 26 provided respectively. In other words, the support wall 30 is provided so that the sealing protrusion 26 and the arrangement position in the boot shaft direction coincide with each other. As shown in FIGS. 2 and 3, the support wall portion 30 is provided over substantially the entire circumferential direction of the overhanging wall portion 24, and the two support wall portions 30 and 30 that receive the fastening member 7. The outer edge 30a is formed along a cylindrical surface common to the arc-shaped wall 22. In other words, the outer edge 30a of the support wall 30 has an arcuate cross-sectional shape that forms a common cylindrical surface with the outer peripheral surface of the fixing recess 20 in the arcuate wall 22, whereby the tightening member 7. Stable tightening due to is ensured.

  The two support wall portions 30, 30 are connected by three connecting walls 32, 34, 32 extending in the axial direction and spaced apart in the circumferential direction, and are reinforced thereby. More specifically, the connecting wall includes a central connecting wall 34 that connects the circumferential centers of the support wall 30 and side connecting walls 32 and 32 that are symmetrically disposed on both sides thereof. As shown, the central connecting wall 34 extends in the radial direction, and the side connecting walls 32, 32 are formed in parallel to the central connecting wall 34.

  In the present embodiment, vertical wall portions 36 and 38 are provided on both sides of the support wall portions 30 and 30 in the axial direction on the outer surface of the overhanging wall portion 24, respectively. The vertical wall portions 36 and 38 have the same contour shape as that of the support wall portion 30. Therefore, in this embodiment, the vertical wall portions 36 and 38 are laterally (in the direction perpendicular to the axis) on the radially inwardly protruding portion of the large-diameter side mounting portion 14. It can also be seen that a meat stealing recess 40 from the outside is provided, and the support wall 30 is provided in the meat stealing recess 40. The vertical wall portions 36 and 38 are not regions tightened by the tightening member 7 and may be omitted.

  In the case of the resin joint boot 10 of the present embodiment configured as described above, since the inwardly projecting portion of the large-diameter side mounting portion 14 has a stealing shape, the projecting portion is formed as a solid thick portion. Compared to the case, it is possible to prevent the occurrence of sink marks due to shrinkage after molding, and it is possible to reduce uneven tightening force between the thick part and the thin part.

  In addition, since the support wall portion 30 that supports the outer surface of the overhanging wall portion 24 is provided so as to overlap the inner circumferential projection ridge 26 via the overhanging wall portion 24, the tightening force by the tightening member 7 Can be reliably exerted on the sealing ridge 26 via the support wall portion 30, and high sealing performance with the outer case 6 is exhibited.

  Furthermore, since the two parallel supporting wall portions 30, 30 extending in the circumferential direction are connected by the connecting walls 32, 34, 32 extending in the axial direction at a plurality of locations in the circumferential direction, tightening by the tightening member 7 is performed. It is possible to prevent the support wall 30 from collapsing at times, and the tightening force by the tightening member 7 can be applied to the sealing protrusion 26 more reliably, leading to further improvement in sealing performance.

  The connection structure by the connection walls 32 and 34 is not limited to the said embodiment, The number and the connection position can be changed suitably. For example, as shown in FIG. 5 (a), by arranging the side connection walls 32, 32 so as to connect both ends of the support wall portions 30, 30, the support wall portion 30 and the connection walls 32, 34 are formed. As a whole, it can also be formed in a letter shape.

In addition, in this invention, as shown in FIG.5 (b), the aspect which does not provide a connection wall between the two support wall parts 30 and 30 is also included .

  Since the joint boot of the present invention can ensure high sealing performance, it can be suitably used as a joint boot mainly used for a triport type constant velocity joint of an automobile.

It is a half section half side view of the resin joint boot concerning one embodiment of the present invention. It is the front view which looked at the joint boot from the large diameter side attaching part side. It is the principal part enlarged view seen from the III direction of FIG. It is the IV-IV sectional view taken on the line of FIG. (A) And (b) is a principal part enlarged view (equivalent to the figure seen from the III direction of FIG. 2 ) of the joint boot concerning other embodiment. It is sectional drawing which shows the triport type constant velocity joint which attached the conventional resin joint boot. It is a side view of an equivalent speed joint.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Resin joint boot, 12 ... Small diameter side attaching part, 14 ... Large diameter side attaching part, 16 ... Bellows part, 22 ... Arc-shaped wall part, 24 ... Overhanging wall part, 26 ... Sealing protrusion, 30 ... Support Wall part, 30a ... outer edge of support wall part, 32, 34 ... connecting wall

Claims (3)

A large-diameter side mounting portion that is externally fixed to the outer case having a plurality of concave portions in the circumferential direction by using a fastening member, a small-diameter side mounting portion that is attached to the shaft, and a bellows that integrally couples the two. A joint boot comprising a portion,
The large-diameter attachment part includes projecting a plurality of arcuate wall portion which is spaced apart in the circumferential direction in a common cylindrical plane, the curved radially inwards between the arc-like wall portion formed And an overhanging wall portion having the same thickness as the arcuate wall portion ,
A plurality of sealing ridges extending in the circumferential direction on the inner side surface of the overhanging wall portion are provided at intervals in the axial direction, and a supporting wall portion extending in the circumferential direction for supporting the outer surface on the outer side surface of the overhanging wall portion A joint boot, wherein a plurality of seal ridges are provided in correspondence with each of the plurality of seal ridges so that the arrangement positions in the axial direction of the boot coincide with those of the seal ridges .   The joint boot according to claim 1, wherein an outer edge of the support wall portion is formed along a cylindrical surface common to the arcuate wall portion. The joint boot according to claim 1 or 2, wherein a plurality of connecting walls extending in the boot axial direction for connecting both of the adjacent supporting wall portions are provided at intervals in the circumferential direction .

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