JP4041115B2 - 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. 8 and 9, 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. 9, the outer case 6 is provided with three circumferentially-arranged concave portions 6 b on the outer periphery corresponding to the arrangement of the inner peripheral sliding grooves 6 a. 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 the inwardly projecting portion 104 of the large-diameter side mounting portion 101 is a solid thick portion as shown in FIG. 8, the thick-walled portion and the thin-walled 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 such a problem, Patent Document 1 below discloses that a large-diameter side mounting portion has a plurality of arc-shaped wall portions arranged in a common cylindrical surface, and an inner side between the arc-shaped wall portions. And a protruding wall portion formed in a curved shape, and a plurality of supporting wall portions that elastically support the protruding wall portion are provided on the outer surface of the protruding wall portion at intervals in the circumferential direction. ing.

  Further, in Patent Document 2 below, a rubber in which a thicker core than a rubber boot is embedded in the thick part of the large-diameter side mounting part, and the thickness of the inner and outer layers of the thick part divided by the center is made uniform. A joint boot made is disclosed.

Further, in Patent Document 3 below, an insert is not provided between the boot and the outer case, instead of forming the inner peripheral shape of the large-diameter side mounting portion of the boot itself into a noncircular shape corresponding to the outer peripheral shape of the outer case. A technique for interposing and ensuring sealing performance is disclosed. That is, Patent Document 3 discloses that the outer peripheral shape is circular between the cylindrical large-diameter side mounting portion of the boot and the non-circular outer case, and the inner peripheral shape is radially inward at a plurality of locations in the circumferential direction. A technique is disclosed in which an insert that is formed to protrude in the direction is interposed.
European Patent Application No. 0915264 Japanese Utility Model Sho 61-54523 JP 55-60726

  In the technique of the above-mentioned Patent Document 1, a plurality of support wall portions are provided on the overhanging portion of the large-diameter side attachment portion, thereby providing a complicated thinning shape on the thick portion of the boot body. This requires a complicated mold configuration, which increases the cost.

  In the technique of Patent Document 2 described above, a complicated mold configuration is required to embed the core in the boot main body, which causes high costs. In addition, when the core is attached to the large-diameter side mounting portion by press-fitting after the boot body is molded, as shown in FIG. 1 of Patent Document 2, the central core extends from the end surface of the large-diameter side mounting portion to the boot shaft. Therefore, when the outer periphery of the large-diameter side mounting part is tightened with a fastening member such as a ring-shaped band, the core may be displaced in the axial direction and fall off the large-diameter side mounting part. Inferior workability.

  In the technique of Patent Document 3, since the insert is interposed between the boot and the outer case, there are two seal portions between the outer case and the insert and between the insert and the boot. Since high accuracy is required for the seal portion, when the number of seal portions is increased in this way, it becomes more difficult to manage the dimensions.

  The present invention has been made in view of such points, and in a joint boot attached to a non-circular outer shape outer case such as a triport type constant velocity joint, the sealing performance is high and low. The object is to provide a product that is excellent in assembly workability and easy to manage in terms of cost.

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. In the projecting portion, a meat stealing recess that is recessed radially inward is provided on the outer peripheral surface of the large-diameter side mounting portion so as to leave vertical wall portions at both ends in the axial direction of the projecting portion. A resin insert is inserted in the stealing recess, and the insert is formed larger than the meat stealing recess and is held by being press-fitted into the meat stealing recess, and the meat stealing recess On the bottom of An inner wall portion that is fitted so as to be in contact with the entire surface, a peripheral wall portion that is fitted to the vertical wall portions at both ends in the axial direction, and an inner wall portion that is provided on an outer surface of the inner wall portion. A support wall portion that supports the two axial support wall portions extending in the axial direction, and a midpoint between the two axial support wall portions. The insert is provided with a circumferential support wall portion extending in the circumferential direction to be connected and reinforced, whereby the insert is provided with four meat stealing holes that are recessed radially inward from the outer surface .

  In the joint boot of the present invention, by providing a meat stealing recess that is recessed in the radial direction on the outer peripheral surface of the large-diameter side fitting portion that is fitted to the concave portion of the outer case. As compared with the case where the projecting portion is formed of a solid thick portion, the occurrence of sink marks due to shrinkage after molding can be prevented. Moreover, a high sealing performance can be ensured by inserting a separate insert into the meat stealing recess and fastening the outer periphery with a fastening member.

  In the joint boot of the present invention, the outer edge of the insert that is tightened by the tightening member is formed along the circular outer peripheral shape of the large-diameter side attachment portion, so that the tightening performance by the tightening member is stable. It is preferable in securing.

Further, according to the joint boot of the present invention, since the thickness-reducing hole in several are provided in the insert, it is possible to sink due to contraction after molding the insert itself can be prevented. Further, in the case of the insert , the tightening force by the outer peripheral tightening member is transmitted to the inner wall portion via the support wall portion, and is exerted in an equalized state over the entire bottom surface of the meat stealing recess by the inner wall portion. Therefore, variation in the tightening force in the circumferential direction can be reduced.

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

  Further, according to the present invention, the mold configuration for molding the boot body can be simplified and the cost can be reduced as compared with Patent Document 1 described above. Furthermore, the cost can be reduced by forming the insert with a material having a lower cost than the material constituting the boot body.

  Further, in the case of Patent Document 2, since the core is inserted in the axial direction from the end face of the large-diameter side mounting portion, there is a possibility that the core may fall off or shift in the axial direction when tightening with the tightening member. According to the present invention, the insert is covered with the fastening member from the outer periphery so as to cover the insert. Therefore, there is no such inconvenience and the assembly workability is excellent.

  In the present invention, since a separate insert is used, the seal portion is only one portion between the outer case and the boot. Therefore, compared with the case of Patent Document 3, the seal portion is used. Dimension management is also easy.

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

1 is a half sectional side view of a joint boot 10 according to a reference example , FIG. 2 is a front view of the large diameter side, and FIG. 3 is a sectional view taken along line III-III in FIG. 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. 8 and 9, 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 tripport 4 side using a tightening member 8, and a circumferential direction for receiving the ring-shaped tightening member 8 on the outer peripheral surface. A fixing recess 18 extending in the direction is provided. The large-diameter side mounting portion 14 has a substantially short cylindrical shape that is externally fixed to the outer case 6 using the fastening member 7, and is coaxial with the small-diameter side mounting portion 12, that is, has a common center line L. Arranged to have. 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 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. As a result, the large-diameter side mounting portion 14 has an arcuate wall portion 22 arranged on the arcuate outer peripheral surface of the outer case 6 and an overhang portion 24 fitted to the concave portion 6b of the outer case 6 in the circumferential direction. It is arranged alternately.

  The outer surface of the arc-shaped wall portion 22 is provided with two circumferentially extending ridges 26, 26 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.

  The overhanging portion 24 is provided with a meat stealing concave portion 28 from the side (outward in the direction perpendicular to the axis) that is recessed inward in the radial direction on the outer peripheral surface thereof. The meat stealing recess 28 is provided over the entire circumferential direction in each overhanging portion 24, and the depth thereof is such that the bottom wall portion 30 of the meat stealing recess 28 has substantially the same thickness as the arcuate portion 22. And it is set so that it may become deep gradually gradually in the circumferential direction center side of the overhang | projection part 24 so that it may have substantially constant thickness in the circumferential direction. The meat stealing recess 28 is provided so as to leave thin vertical wall portions 32 and 34 at both ends in the axial direction of the overhanging portion 24, and is tightened by the tightening member 7 at least in the axial direction of the overhanging portion 24. It is formed over the entire area.

  A resin insert 36 is inserted into each meat stealing recess 28 and is tightened by the tightening member 7 on the outer periphery. In this embodiment, the insert 36 has an outer shape corresponding to the recess 28 so that the entire meat stealing recess 28 is filled. Then, it is interposed between the meat stealing recess 28 and the tightening member 7, and the tightening force by the outer periphery tightening member 7 is transmitted to the inner bottom wall portion 30, thereby sealing between the outer case 6 and the outer case 6. Is provided to ensure. If the insert 36 can exert a tightening force by the tightening member 7 on the bottom wall portion 30 so as to ensure a sufficient sealing performance between the bottom wall portion 30 and the outer case 6, The shape is not limited.

  An outer edge 36 a of the insert 36 that receives the tightening member 7 is formed along a circular shape on the outer periphery of the large-diameter side attachment portion 14. That is, the outer edge 36 a of the insert 36 has a circular arc-shaped profile that forms a common cylindrical surface with the outer peripheral surface of the fixing recess 20 in the arc-shaped wall portion 22. Tightness is ensured.

The insert 36 is molded separately from the joint boot body, and is usually manufactured by injection molding of a thermoplastic resin. The obtained insert 36 is inserted into the meat stealing recess 28 as shown in FIG. 4 with respect to the joint boot body formed separately. At that time, the insert 36 is allowed to slightly larger than the thinned-out recess 28, Ru is holding the insert 36 in the recess 28 by press-fitting in the recess 28.

  In addition, the material of the insert 36 is not specifically limited, For example, the same resin material as a joint boot main body can also be used. Preferably, a resin material that is less expensive than the joint boot body is used, whereby the overall material cost can be reduced without impairing the performance of the joint boot. As the hardness of the resin, a resin having a hardness comparable to that of the joint boot body is preferably used.

If it is ∎ it can butter made joint boot 10 name above, is provided with the thinned concave portion 28 from the side to the projecting portion 24 inward in the large-diameter attachment part 14, the thickness mid real the overhang portion As compared with the case of forming with a meat part, it is possible to prevent the occurrence of sink marks due to shrinkage after molding. When the resin insert 36 is attached to the meat stealing recess 28 and the outer periphery thereof is tightened with the fastening member 7, the tightening force is transmitted to the bottom wall 30 of the meat stealing recess 28 via the insert 36, High sealing performance can be secured by pressing the bottom wall portion 30 against the outer peripheral surface of the outer case 6.

Further, since the form of di Yointobutsu body is relatively simple, it is possible to simplify the mold structure for molding this, the cost can be reduced. Further, since the fastening member 7 is tightened from the outer periphery so as to cover the insert 36, there is no problem that the insert 36 falls off during fastening, and the assembly workability is excellent. Furthermore, since a separate insert is used, the seal portion itself is only one place between the outer case 6 and the boot body, so that the size control for the seal portion requiring accuracy is easy. .

  5 to 7 show specific examples of the insert 36. FIG.

In the reference example shown in FIG. 5, the insert 36 includes an inner wall portion 40 that fits to the bottom surface 28 a of the meat stealing recess 28, a rectangular frame-shaped peripheral wall portion 42 that fits to the inner peripheral surface of the meat stealing recess 28, and A support wall portion 44 is provided on the outer surface of the inner wall portion 40 and supports the inner wall portion 40 with respect to the fastening member 7.

  The support wall portion 44 includes a circumferential support wall portion 44a extending from one end to the other end in the circumferential direction of the insert 36, and an axial support wall portion 44b extending in the axial direction so as to intersect at right angles thereto. The circumferential support wall portion 44 a is reinforced by the intersecting axial support wall portions 44 b, and the outer edge thereof is formed along the circular outer peripheral shape of the large-diameter side attachment portion 14. The circumferential support wall 44a and the axial support wall 44b are provided along the axial center line and the circumferential center line of the insert 36, respectively, so as to intersect each other at the midpoint. Thus, the insert 36 is provided with a plurality (four) of meat stealing holes 46 that are recessed radially inward from the outer surface thereof.

In the embodiment of the present invention shown in FIG. 6, the support wall portion 44 has two axial support wall portions 44 c and 44 c extending in the axial direction, and a periphery that connects and reinforces the midpoints of both. And a circumferential support wall 44d extending in the direction. Thus, the insert 36 is provided with a plurality (four) of meat stealing holes 48 that are recessed radially inward from the outer surface thereof.

In the reference example shown in FIG. 7, the insert 36 is provided with a plurality of meat theft holes 50 penetrating in the thickness direction. The meat stealing holes 50 have an elliptical cross section, and a plurality (six) are provided at predetermined intervals.

  As described above, by providing the insert 36 with the plurality of meat steal holes 46, 48, 50, it is possible to prevent the occurrence of sink marks due to the shrinkage of the resin insert itself after molding.

  In particular, in the example of FIGS. 5 and 6, the tightening force by the outer peripheral tightening member 7 is transmitted to the inner wall portion 40 via the support wall portion 44. Since the inner wall portion 40 is disposed so as to be in contact with the entire bottom surface 28a of the meat stealing recess 28, the tightening force transmitted to the inner wall portion 40 is exerted on the entire bottom surface 28a of the meat stealing recess 28 in an equalized state. Thus, variation in the tightening force in the circumferential direction is reduced. Furthermore, as shown in FIG. 5, when the circumferential support wall portion 44a extending in the entire circumferential direction of the insert 36 is provided, the variation in the tightening force in the circumferential direction can be further reduced, and high sealing performance can be secured. it can.

  The joint boot of the present invention has high sealing performance, is low in cost, is excellent in assembling workability, and is easy to control dimensions. Therefore, the joint boot is mainly used for a triport type constant velocity joint of an automobile. Can be suitably used.

It is a half section half side view of the resin joint boot concerning a reference example . It is the front view which looked at the joint boot from the large diameter side attaching part side. It is the III-III sectional view taken on the line of FIG. It is a disassembled perspective view which expands and shows the principal part of the joint boot. It is a figure which shows one reference example of insert, (a) is a top view, (b) is the AA sectional view taken on the line. It is a figure which shows the example which concerns on embodiment of insert, (a) is a top view, (b) is the BB sectional drawing. It is a figure which shows the other reference example of insert, (a) is a top view, (b) is the CC sectional view taken on the line. 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, 24 ... Overhang part, 28 ... Meat stealing recessed part, 28a ... Bottom face of meat stealing recessed part, 36 ... Insert, 40 ... inner wall part, 44 ... support wall part, 46, 48, 50 ... meat steal hole, 7 ... tightening member

Claims (2)

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 the inner peripheral shape projects radially inward at a plurality of locations in the circumferential direction, and the outer peripheral surface of the large-diameter side mounting portion is in the protruding portion. A meat stealing recess recessed inward in the radial direction is provided so as to leave vertical wall portions at both ends in the axial direction of the overhanging portion, and a resin insert is inserted into the meat stealing recess ,
The insert is formed larger than the meat stealing recess and is held by being press-fitted into the meat stealing recess, and is fitted inside so as to contact the entire bottom surface of the meat stealing recess. A wall portion, a peripheral wall portion fitted to the vertical wall portions at both ends in the axial direction, a support wall portion provided on an outer surface of the inner wall portion and supporting the inner wall portion with respect to the fastening member, With
The support wall portion includes two axial support wall portions extending in the axial direction, and a circumferential support wall portion extending in the circumferential direction for connecting and reinforcing the midpoints of the two axial support wall portions. Thus, the insert was provided with four meat theft holes that were recessed radially inward from the outer surface,
Joint boots.   The joint boot according to claim 1, wherein an outer edge of the insert is formed along a circular outer peripheral shape of the large-diameter side attachment portion.

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