JP2006118529A - Joint boot - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure high sealing performance without deteriorating a moldability in a joint boot mounted in an outer case with a non-circular outer peripheral form like a tri-port constant velocity joint. <P>SOLUTION: In a large diameter side mounting part 14 externally fitted and fixed with respect to an outer case 6 by employing a clamping member 7, the inner peripheral shape is formed so as to be protruded inward in a peripheral direction in a plurality of circumferential parts. Lightening holes 34, 36 extend in an axial direction from an end surface of the large diameter side mounting part 14 are provided to the protruded part 24. A recessed part 42 recessed inward in a radial direction is provided to an area 40 on a bellows side from a area 38 clamped by the clamping member 7 in the large diameter side mounting part 14 so as to be formed in a thin thickness shape. <P>COPYRIGHT: (C)2006,JPO&NCIPI

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. 9 and 10, the triport type constant velocity joint has three trunnions 3 having rollers 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. 10, the outer case 6 is provided with three evenly arranged concave portions 6 b in the circumferential direction on the outer circumference corresponding to the arrangement of the sliding grooves 6 a on the inner circumference. 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. 10, 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. In order to solve such a problem, the following Patent Document 1 discloses an inner wall portion projecting inwardly in a large-diameter side mounting portion, and an arc-shaped outer wall portion on the outer peripheral side. And an example of a support wall that connects the inner wall portion and the outer wall portion, and is configured with a plurality of support walls that are arranged at equal intervals in the circumferential direction and extend in parallel with each other. Patent Document 2 below discloses an example in which the inner wall portion and the outer wall portion are connected by a single support wall at the center in the circumferential direction of the both. Patent Document 3 below discloses an example 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 JP 2003-329057 A JP 2002-122237 A

  In the techniques disclosed in Patent Literature 1 and Patent Literature 2, the inwardly extending portion of the large-diameter side attachment portion is provided with a hollow hole extending in the axial direction from the end surface of the large-diameter side attachment portion. Therefore, the above-mentioned sealing performance is being improved. However, in the case of the hollow hole extending in the axial direction, if the axial dimension of the large-diameter side attachment portion is large, it is necessary to increase the axial dimension of the hollow hole accordingly. When the axial dimension of the lightening hole is increased in this way, the core for molding this becomes long, so that there is a problem that the core is difficult to be removed at the time of molding the large-diameter side mounting portion, and thus the moldability is impaired. .

  On the other hand, in the technique disclosed in Patent Document 3, a plurality of grooves extending in the circumferential direction are arranged in parallel on the outer peripheral surface of the large-diameter side mounting portion where a fastening member such as a ring-shaped band is arranged. Such a tightening region by a band or the like is desirably a flat cylindrical surface without a groove in order to perform stable tightening.

  The present invention has been made in view of the above points, and in a joint boot attached to a non-circular outer shape outer case such as a triport type constant velocity joint, tightening without impairing formability. It is an object of the present invention to provide a joint boot that can be stably tightened by an attaching member and has excellent sealing properties.

  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 mounting part has a circular outer peripheral shape, while an inner peripheral shape is radially inward at a plurality of locations in the circumferential direction. The overhanging portion is provided with one or more hollow holes extending in the axial direction from the end surface of the large-diameter side attachment portion, and more than a tightening region by the tightening member in the large-diameter side attachment portion. In the region on the bellows portion side, the outer peripheral surface falls inward in the radial direction at the projecting portion, so that the region on the bellows portion side in the projecting portion is formed thin.

  By providing a hollow hole extending in the axial direction from the end surface of the overhang portion in this way, it prevents the occurrence of sink marks due to shrinkage after molding compared to the case where the overhang portion is formed of a solid thick portion. It is possible to improve moldability and sealability. In addition, since the hollow hole extends in the axial direction, the tightening region to be tightened by the tightening member can be formed into a flat cylindrical surface, thereby enabling stable tightening. And while providing such a hollow hole extending in the axial direction, in the region closer to the bellows portion than the tightening region, the outer peripheral surface is recessed inward in the radial direction at the overhanging portion, so that it is thinned. The thick shape at the overhanging portion can be eliminated even in the region on the bellows portion side of the attached region. For this reason, even when the axial dimension of the large-diameter side attachment portion becomes large, it is not necessary to increase the axial dimension of the above-mentioned hollow hole, so that there is no problem of poor formability.

  In the joint boot of the present invention, the radially inwardly depressed portion of the projecting portion is a linearly depressed portion extending in the chord direction, and an arc-shaped wall interposed between the two projecting portions at both ends thereof May be connected to the unit. In this case, if it is the above-mentioned linear depression part with respect to the overhanging part which protrudes in the curved surface shape, the both ends will protrude inward beyond the overhanging part. Therefore, by making this projecting part abut on the front end surface of the outer case, it is possible to position the boot in the axial direction when assembling to the outer case, and to improve the assembling workability. .

  In the joint boot of the present invention, the large-diameter side attachment portion in the overhanging portion has an inner wall portion projecting radially inward and a part of the outer peripheral surface of the large-diameter side attachment portion. An outer wall portion, a radially extending central support wall connecting the inner wall portion and the outer wall portion at the center in the circumferential direction thereof, and left and right connecting the inner wall portion and the outer wall portion on both sides of the central support wall It is preferable that the above-mentioned side hole is formed, and the side support wall is inclined so as to approach the central support wall toward the outside.

  Thus, by providing the side support wall so as to be closer to the center support wall toward the outer side, it is possible to ensure the demoldability of the core for forming the lightening hole. In addition, the side support wall that supports the outer surface of the inner wall portion can be coupled at an angle close to perpendicular to the inner wall portion, and the surface pressure exerted on the outer case by the inner wall portion can be made uniform in the circumferential direction. Can do.

  In the joint boot of this invention, it is preferable that the said side support wall is couple | bonded with the inner wall part in the intermediate position of the connection part with the center support wall in an inner wall part, and the root part to an outer wall part. . The weakest part on both sides of the connecting part with the central support wall in the inner wall part is the midpoint between the connecting part and the base part to the outer wall part, so the inner wall part is supported by the side support wall at this position. If reinforced as described above, it is more effective for uniforming the surface pressure to the outer case by the inner wall portion.

  According to the present invention, in a joint boot attached to a non-circular outer shape outer case such as a triport type constant velocity joint, stable tightening by a tightening member can be performed without impairing formability. High sealing performance can be obtained.

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

  FIG. 1 is a perspective view of a joint boot 10 according to an embodiment of the present invention, FIG. 2 is a half sectional side view thereof, FIG. 3 is a front view of its large diameter side, and FIG. 4 is a front view of its small diameter side. It is. This joint boot 10 is a thermoplastic elastomer resin boot to be mounted on the above-described triport type constant velocity joint for automobiles shown in FIGS. 9 and 10, 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 attachment portion 14 has a short cylindrical shape that is fitted and fixed to the outer case 6, and is arranged coaxially with the small-diameter side attachment portion 12, that is, has a common center line L. The large-diameter mounting portion 14 is also provided with a fixing recess 20 extending in the circumferential direction for receiving the ring-shaped fastening member 7 on the outer peripheral surface.

  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. 3, the large-diameter side attachment portion 14 has a circular outer peripheral shape. On the other hand, the inner circumferential shape corresponds to the outer circumferential shape of the outer case 6 in which a plurality of (in this embodiment, three) concave portions 6b are evenly arranged in the circumferential direction. A non-circular shape projecting inwardly into a curved surface. Thereby, the large-diameter side mounting portion 14 has an arcuate portion 22 disposed on the arcuate outer peripheral surface of the outer case 6 and an overhanging portion 24 fitted in the concave portion 6b of the outer case 6 in the circumferential direction. It is arranged alternately.

  The projecting portion 24 includes an inner wall portion 26 projecting inward and an outer wall portion 28 on the outer peripheral side having an arc shape, and between the inner wall portion 26 and the outer wall portion 28. A central support wall 30 that connects the wall portions 26 and 28 at the center in the circumferential direction and a pair of left and right side support walls 32 and 32 that connect the wall portions 26 and 28 are provided on the left and right sides of the hollow portion. Yes.

  The outer wall portion 28 is an arc-shaped wall portion having a substantially constant thickness in the circumferential direction, has substantially the same thickness as the arc-shaped portion 22, and is integrated with the arc-shaped portion 22 to form a single unit. It is comprised so that a cylindrical body may be made. The inner wall portion 26 is formed to protrude in a curved surface shape from the inner peripheral surface of the cylindrical body toward the inner side in the radial direction, and has substantially the same thickness as the outer wall portion 28 and a substantially constant thickness in the circumferential direction. Is formed.

  As shown in FIG. 6, the central support wall 30 is a radially extending wall portion that supports the inner wall portion 26 with respect to the outer wall portion 28, and is formed to have substantially the same thickness as the inner wall portion 26. . The central support wall 30 is provided at the center in the circumferential direction where the height of the inner wall 26 protruding inward is the largest.

  The side support wall 32 is a wall portion that supports the inner wall portion 26 with respect to the outer wall portion 28, and is formed to have substantially the same thickness as the inner wall portion 26. The side support wall 32 is not parallel to the central support wall 30 provided radially from the center O of the large-diameter side mounting portion 14 but is inclined so as to approach the central support wall 30 toward the outer side. As a result, a total of three support walls, that is, the left and right side support walls 32, 32 and the central support wall 30, are connected to the outer wall portion 28 of the central support wall 30, that is, the circumferential direction of the outer wall portion 28. The center extends radially from the center toward the inner wall portion 26.

  More specifically, the side support wall 32 is configured so that the inner wall portion 26 is supported by the central support wall 30 and the side support walls 32 and 32 at equal intervals in the circumferential direction. The inner wall portion 26 is supported at an intermediate position between the base portion 26a and the connecting portion 26b of the central support wall, that is, connected to the inner wall portion 26 at the intermediate position. Further, the connecting portion is provided so as to be substantially perpendicular to the inner wall portion 26 so as to be inclined toward the center, that is, closer to the central support wall 30 as going outward from the connecting portion. Here, it is preferable that the coupling angle θ of the side support wall 32 with respect to the inner wall portion 26 is substantially vertical. Specifically, the coupling angle θ is within a range of 70 ° to 110 ° (that is, 90 ° ± 20 °). It is preferable that it exists, More preferably, it exists in the range of 80 degrees-100 degrees. The coupling angle θ is an angle formed between the center line N of the side support wall 32 and a tangent line P on the inner peripheral surface of the inner wall portion 26 intersecting the center line N.

  With such a configuration, the overhanging portion 24 is provided with a plurality of (four in this example) hollow portions 34, 36, 36, 34 that are arranged in the circumferential direction. These hollow holes 34, 36, 36, 34 are provided symmetrically with respect to the circumferential center line M of the overhanging portion 24, and as shown in FIG. 5, the end face (bellows portion 16) of the large-diameter side mounting portion 14 is provided. (The end face on the opposite side) and recessed in the axial direction of the boot 10. The pair of inner hollow holes 36, 36 partitioned by the central support wall 30 has a triangular cross section with an apex angle directed radially outward, and the pair of outer hollow holes 34 on the outer side. , 34 have a triangular cross section with an apex angle directed radially inward.

  As shown in FIG. 2, the lightening holes 34, 36, 36, 34 are provided in a tightening region 38 by the tightening member 7 in the overhang portion 24. Here, the tightening region 38 is a region having a fixing recess 20 on the outer periphery to which the tightening member 7 is fitted. In the region 40 closer to the bellows portion 16 than the tightening region 38, the outer peripheral surface of the large-diameter side attachment portion 14 has a circumferential portion corresponding to the overhang portion 24 that falls inward in the radial direction. A region 40 on the accordion portion side in the overhang portion 24 is formed in a thin shape. That is, the overhanging portion 24 is provided with the lightening holes 34 and 36 extending in the axial direction from the boot end surface in the tightening region 38, and in the region 40 on the bellows portion side, the side by the depression portion 42 inward in the radial direction. A meat stealer from the direction is provided.

  In this embodiment, as shown in FIGS. 1 and 2, the sagging portion 42 is formed by the shoulder portion adjacent to the bellows portion 16 in the overhang portion 24 being depressed inward in the radial direction. As shown in FIGS. 1, 3, and 4, the sagging portion 42 has a form in which the shoulder portion is cut into an arcuate cross section at three locations in the circumferential direction corresponding to the overhanging portion 24. Is a linear drop portion extending in the chord direction of the large-diameter side attachment portion 14, and is connected to an arcuate wall portion 44 interposed between two adjacent overhang portions 24, 24 at both ends thereof. . As shown in FIG. 3, the linear drop portion 42 is formed symmetrically with respect to the circumferential center line M of the overhang portion 24, and the inner surface height of the drop portion 42 and the overhang portion 24 in the center line M. Match.

  The thickness at the sagging portion 42 is set to be substantially the same as that of the arcuate wall portion 44, and further, the thickness is set to be substantially the same as that of the inner wall portion 26 described above. ing. Thereby, as for the large diameter side attaching part 14, the thickness of each part in the overhang | projection part 24 is made into thin shape also including the vertical wall part 46 which comprises the bottom wall of a hollow hole.

  In the resin joint boot 10 of the present embodiment configured as described above, the overhanging portions 24 and 36 are provided in the overhanging portion 24 of the large-diameter side mounting portion 14, and thus the overhanging portion is formed with a solid thick portion. Compared to the case, the occurrence of sink marks due to shrinkage after molding can be prevented.

  Further, since the hollow holes 34 and 36 are hollow holes extending in the axial direction, the inside of the fixing concave portion 20 in the tightening region 38 can be formed into a flat cylindrical surface, and thus stable tightening is possible. Become.

  Further, since the region 40 closer to the bellows part than the tightening region 38 is thinned by the side-to-side depression part 42, the axial dimension of the overhanging part 24 can be reduced while keeping the axial dimension of the hollow holes 34 and 36 small. It is possible to prevent the occurrence of sink marks in the entire direction.

  Moreover, since it is the linear drop part 42 as mentioned above, as shown in FIG. 3, it will become the form which the both ends of the drop part 42 protruded inward with respect to the curved surface-shaped overhang | projection part 24. As shown in FIG. For this reason, if the projecting portion 42a is assembled so as to abut on the distal end surface 6c of the outer case 6, the large-diameter side mounting portion 14 can be positioned in the axial direction, thereby improving the assembling workability. be able to. Moreover, since the sagging part 42 is linear, it is excellent also in the mold release property after shaping | molding.

  Further, as the lightening shape in the tightening region 38, the side operation wall 32 is inclined with respect to the central support wall 30 as described above, and the following operational effects are exhibited. That is, when the side support wall 32 is arranged in parallel to the central support wall 30, the cross-sectional area of the lightening hole 34 on the outside of the side support wall 32 becomes small, and the lightening hole 34 is formed. Although it is difficult to remove the core, the cross-sectional area of the outer lightening hole 34 is made to be the same as the cross-sectional area of the inner lightening hole 36 by inclining toward the central support wall 30 as described above. Therefore, it is possible to secure the mold release property of the core for forming these hollow holes and improve the moldability.

  In addition, the side support wall 32 that supports the outer surface of the inner wall portion 26 can be coupled to the inner wall portion 26 at an angle close to vertical by the above inclination. Therefore, when the large-diameter side attachment portion 14 is fastened and fixed using the fastening member 7, the surface pressure exerted on the outer case 6 by the inner wall portion 26 can be made uniform in the circumferential direction, and the seal at the overhang portion 24 is achieved. Can be improved.

  FIG. 7: is the front view seen from the large diameter side attaching part 14a side of the joint boot concerning other embodiment, and FIG. 8 is the principal part expanded sectional view. This embodiment differs from the above-described embodiment in the inclination angles of the left and right side support walls 32, 32 in the projecting portion 24 of the large-diameter side attachment portion 14a.

  That is, in this embodiment, the coupling angle θ with respect to the inner wall portion 26 of the side support wall 32 is set to be an angle closer to 90 ° than in the above embodiment. Thus, in the present embodiment, among the four lightening holes 34, 36, 36, 34 provided in the overhanging portion 24, the pair of inner lightening holes 36, 36 partitioned by the central support wall 30. The cross-sectional shape is different from the above embodiment. In other words, in this embodiment, the pair of hollow holes 36 and 36 on the inner side have a trapezoidal cross-sectional shape in which the outer peripheral surface side of the large-diameter side attachment portion 14a is narrowed. In addition, the pair of outer side holes 34, 34 on the outside have a triangular cross section similar to the above embodiment. Other configurations are the same as those of the above-described embodiment, and the same effects as those of the above-described embodiment are exhibited in this embodiment. In particular, in this embodiment, the coupling angle θ of the side support wall 32 with respect to the inner wall portion 26 is set to an angle closer to 90 ° than in the above-described embodiment. The surface pressure at the inner wall portion 26 can be made more uniform, and the sealing performance at the overhang portion 24 can be improved.

  Since the joint boot of the present invention can ensure high sealing performance without impairing moldability, it can be suitably used as a joint boot mainly used for a triport type constant velocity joint of an automobile.

1 is a perspective view of a resin joint boot according to an embodiment of the present invention. It is a half section half side view of the joint boot. It is the front view which looked at the joint boot from the large diameter side attaching part side. It is the front view which looked at the joint boot from the small diameter side attaching part side. It is a principal part expanded sectional view of the joint boot. It is the VI-VI sectional view taken on the line of FIG. It is the front view which looked at the joint joint boots made from resin concerning other embodiments from the large diameter side attaching part side. It is a principal part expanded sectional view of the joint boot of FIG. 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, 14a ... Large diameter side attaching part, 16 ... Bellows part, 24 ... Overhang part, 26 ... Inner side wall part, 26a ... Outer wall part of inner side wall part , A base portion of the inner wall portion, 28 ... an outer wall portion, 30 ... a central support wall, 32 ... a side support wall, 34, 36 ... a hollow hole, 38 ... a tightening region, 40: region on the side of the bellows part, 42: sagging part, 44 ... arc-shaped wall part

Claims (4)

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 side mounting portion has a circular outer peripheral shape, while an inner peripheral shape projects radially inward at a plurality of locations in the circumferential direction, and the projecting portion extends from an end surface of the large-diameter side mounting portion. One or a plurality of lightening holes extending in the axial direction are provided, and the outer peripheral surface is radially inward at the overhanging portion in a region closer to the bellows portion than the tightening region by the tightening member in the large-diameter side mounting portion. The joint boot is characterized in that the region on the bellows portion side in the overhanging portion is formed in a thin shape by falling into the shape.   The radially inwardly depressed portion of the projecting portion is a linearly depressed portion extending in the chord direction, and is connected to an arcuate wall portion interposed between two projecting portions at both ends thereof. The joint boot according to claim 1.   In the overhanging portion, the large-diameter side mounting portion includes an inner wall portion that projects radially inwardly, an arc-shaped outer wall portion that constitutes a part of the outer peripheral surface of the large-diameter side mounting portion, and these inner sides A central support wall extending in the radial direction connecting the wall portion and the outer wall portion at the center in the circumferential direction thereof, and left and right side support walls connecting the inner wall portion and the outer wall portion on both sides of the central support wall. The joint boot according to claim 1, wherein the side support wall is inclined so as to approach the central support wall toward the outside.   The side support wall is coupled to the inner wall portion at an intermediate position between a connection portion of the inner wall portion with the central support wall and a base portion to the outer wall portion. 3. Joint boot according to 3.

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