JP2012207767A - Rubber boot for constant velocity joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber boot for a constant velocity joint that can avoid interference between a staking protrusion part and a bellows part when a fastening clamp having the staking protrusion part is used.SOLUTION: In a cross section containing an axial center O of the rubber boot 10, a distance in a radial direction K between the apex 28a of a first crest 28 adjacent to a small diameter cylinder part 12 and the bellows side opening end 18a of a clamp recessed groove 18 is defined as A; a distance in the axial direction X between the apex 28a of the first crest 28 and the bellows side opening end 18a of the clamp recessed groove 18 is defined as B; the radius of curvature of a connection part 40 having a circular cross section connecting between the outer slope 28b of the first crest and the outer periphery 12a of the small diameter cylinder part is defined as C; and the length of a perpendicular line q drawn from an inner slope 28c to the outer slope 28b of the first crest part with a boundary portion P between the connection part 40 and the outer slope 28b as the foot of the perpendicular line, is defined as D, and following relations are set: B/A≥0.80, C/A≥0.32, and D/A≥0.26.

Description

  The present invention relates to a rubber boot mainly used for a constant velocity joint of an automobile.

  The joint of the drive shaft of a vehicle such as an automobile is fitted with a bellows-like joint boot that can be appropriately expanded and contracted or bent in order to retain the enclosed grease or prevent the entry of dust and foreign substances. A rubber boot for a constant velocity joint made of a rubber material such as chloroprene rubber is known (for example, see Patent Document 1 below).

  FIG. 5 shows an example of a state in which a conventional rubber boot for a constant velocity joint is assembled to a constant velocity joint. The constant velocity joint is provided at one end of the shaft 5 on the driving side and the driven side, and a triport 4 formed by projecting three trunnions 3 having rollers 2 in a direction perpendicular to the axis, and the other shaft 5. The outer case 6 has three sliding grooves 6a in the axial direction corresponding to the triport 4 on its inner periphery, and the roller 2 of the triport 4 is fitted along the sliding groove 6a. ing. As a result, the constant velocity joint is configured to transmit rotational torque while allowing an angle (joint angle) between the shafts 1 and 5 and allowing sliding in the axial direction. .

  The rubber boot 100 includes a large-diameter cylindrical portion 101 that is fitted to the outer case 6, a small-diameter cylindrical portion 102 that is fitted to the shaft 1, and a bellows portion 103 that integrally couples the rubber boot 100. Covering the portion of the shaft 1 on the 4 side, it is configured to be able to expand and contract and bend. Annular clamp grooves 104 and 105 are provided on the outer peripheral surfaces of the large-diameter cylinder portion 101 and the small-diameter cylinder portion 102, respectively, and ring-shaped tightening clamps 7 and 8 are attached to the clamp recess grooves 104 and 105, respectively. By tightening from the outside, the large-diameter cylindrical portion 101 and the small-diameter cylindrical portion 102 are fixed to the outer case 6 and the outer peripheral surface of the shaft 1, respectively.

  Conventionally, in this type of rubber boot 100, the difference in the ridge / valley diameter of the bellows portion 103 is set so as to follow the movement of the constant velocity joint as much as possible, and the first peak portion 106 closest to the small diameter cylindrical portion 102 is set. Also for the shape, as shown in FIG. 6, the dimension A, which is the height from the outer peripheral surface of the small-diameter cylindrical portion 102, was set large. In addition, regarding the distance from the small-diameter cylindrical portion 102, the B dimension, which is the axial distance from the apex of the first peak portion 106 to the clamp groove 105, was set small.

JP 2001-165188 A

  By the way, as the clamping clamp, there is a case where a clamping clamp (for example, an omega clamp or the like) having a caulking convex portion protruding radially outward at one place in the circumferential direction is used. When such a clamping clamp is installed in the clamp groove on the outer peripheral surface of the small-diameter cylindrical portion, the caulking convex portion and the bellows portion (that is, the first peak portion) are used in the conventional one having the first peak shape. May come into contact. In detail, even in the above-described conventional shape, the maximum joint angle in the actual vehicle mounting state does not necessarily mean that the caulking convex portion and the bellows portion interfere with each other, but the maximum movable angle of the joint itself before vehicle mounting (vehicle mounting) It is desirable that the caulking convex portion and the bellows portion do not interfere with each other even if it is larger than the maximum joint angle.

  An object of the present invention is to provide a rubber boot for a constant velocity joint that can avoid interference between a caulking convex portion and a bellows portion when a clamping clamp having a caulking convex portion is used in view of the above points. And

The rubber boot for a constant velocity joint according to the present invention has a small-diameter cylindrical portion provided with an annular clamp groove on the outer peripheral surface, and is coaxially disposed apart from the small-diameter cylindrical portion and has a larger diameter than the small-diameter cylindrical portion. A plurality of peaks including a first peak portion, a first valley portion, and a second peak portion in order from the small diameter cylindrical portion side, which are integrally connected to the large diameter cylindrical portion, and the small diameter cylindrical portion and the large diameter cylindrical portion. A rubber boot for a constant velocity joint having a bellows portion in which a portion and a valley portion are alternately continuous, and in the cross section including the axial center of the rubber boot, the following dimensions A to D are set as follows: It is a thing.

B / A ≧ 0.80, C / A ≧ 0.32, and D / A ≧ 0.26
A: Distance in the radial direction between the apex of the first peak and the bellows side opening end of the clamp groove B: The axis between the apex of the first peak and the bellows side opening end of the clamp groove Distance in direction C: Radius of curvature of the connecting portion having an arcuate cross section connecting the outer slope of the first peak portion and the outer peripheral surface of the small-diameter cylindrical portion D: the boundary point between the connecting portion and the outer slope The length of the perpendicular dropped from the inner slope of the first peak to the outer slope as a leg of the perpendicular.

  With the rubber boot for constant velocity joint according to the present invention, when the tightening clamp having a caulking convex portion is mounted on the concave groove of the small diameter cylindrical portion by the above dimension setting, the first peak portion of the bellows portion and the caulking convexity are mounted. Interference with the part can be avoided.

It is a half cross-sectional half side view of the rubber boot for constant velocity joints which concerns on one Embodiment. It is a principal part expanded sectional view around the small diameter cylinder part of the rubber boot. It is a side view which shows the mounting state to the constant velocity joint of the rubber boot. It is an enlarged view of the caulking convex part seen from the IV direction of FIG. It is sectional drawing which shows the mounting state to the constant velocity joint of the conventional rubber boot. It is a principal part expanded sectional view around the small diameter cylinder part of the conventional rubber boot.

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

  A rubber boot for a constant velocity joint according to the embodiment (hereinafter sometimes simply referred to as a rubber boot) 10 is a rubber boot that is attached to a constant velocity joint of an automobile, and is attached to a shaft 1 as shown in FIGS. The small-diameter cylindrical portion 12, the large-diameter cylindrical portion 14 attached to the outer case 6, and the bellows portion 16 that integrally connects the small-diameter cylindrical portion 12 and the large-diameter cylindrical portion 14. The rubber boot 10 is made of a rubber material such as chloroprene rubber, and has completely different characteristics from the resin boot in terms of flexibility and the like. Therefore, in general, in setting the shape and thickness of the bellows portion, etc. It is clearly distinguished from resin boots. The configuration of the constant velocity joint itself is the same as that of the conventional art, and the description thereof is omitted.

  The small-diameter cylindrical portion 12 has a short cylindrical shape that is fitted and fixed to the outer peripheral surface of the shaft 1, and the outer peripheral surface 12 a of the small-diameter cylindrical portion 12 has a circumferential direction for receiving a ring-shaped clamping clamp 8. Is provided over the entire circumference (and thus in an annular shape). Further, on the inner peripheral surface 12 b of the small diameter cylindrical portion 12, a seal protrusion 20 is provided that fits into a seal groove (not shown) provided on the outer peripheral surface of the shaft 1.

  As shown in FIGS. 3 and 4, the clamping clamp 8 mounted in the clamp groove 18 has a caulking convex portion 8 a protruding radially outward at one place in the circumferential direction as shown in FIGS. 3 and 4. Fastening clamps called omega clamps are used. As shown in FIG. 4, the clamping clamp 8 is wound around the outer periphery of the clamp groove 18 and then caulked so that a part of the circumferential direction is sandwiched from the left and right by a caulking jig (not shown). A caulking convex portion 8a having a substantially Ω shape is formed.

  The large-diameter cylindrical portion 14 has a larger diameter than the small-diameter cylindrical portion 12 and has a short cylindrical shape that is fitted and fixed to the outer peripheral surface of the outer case 6. A circumferentially extending concave groove 22 for receiving the ring-shaped clamping clamp 7 is provided over the entire circumference. Further, on the inner peripheral surface of the large-diameter cylindrical portion 14, a seal protrusion 24 is provided that fits in a seal groove (not shown) provided on the outer peripheral surface of the outer case 6. The large-diameter cylindrical portion 14 is arranged coaxially apart from the small-diameter cylindrical portion 12, that is, the small-diameter cylindrical portion 12 and the large-diameter cylindrical portion 14 have a common axis as the axis O of the rubber boot 10. Is arranged.

  The bellows portion 16 is a bellows body having a circular cross section with a difference in diameter at both ends, and a grease filled space 26 is formed therein. In this example, the bellows portion 16 is, in order from the small diameter cylindrical portion 12 side, the first peak portion 28, the first valley portion 30, the second peak portion 32, the second valley portion 34, the third peak portion 36, and the third valley portion. 38 and has a bellows structure in which a plurality of peaks and valleys are alternately and continuously formed. The outer diameters of the crests and troughs are set so as to increase sequentially from the small diameter cylindrical part 12 to the large diameter cylindrical part 14, respectively.

  In the present embodiment having the above basic configuration, in the present embodiment, in order to avoid interference between the caulking convex portion 8a and the bellows portion 16 (first peak portion 28), the shape of the first peak portion 28 is as follows. Is set to

  In the cross section including the axial center O of the rubber boot 10 shown in FIG. 2, the following dimensions A to D are defined.

  A: Distance (mm) in the radial direction (that is, the direction perpendicular to the axis) K between the apex 28a of the first peak portion 28 and the bellows-side opening end 18a of the clamp groove 18. Here, the bellows part side opening end 18 a is a position that coincides with the outer peripheral surface 12 a of the small diameter cylindrical part 12 at the end of the clamp groove 18 on the bellows part 16 side, and the clamp groove 18 that is clamped by the clamping clamp 8. It is a radial position of the opening surface part which went up one step from the bottom face. Therefore, the dimension A is the distance in the radial direction K between the outer peripheral surface 12a of the small diameter cylindrical portion 12 and the apex 28a of the first peak portion 28, and coincides with the peak height of the first peak portion 28 from the outer peripheral surface 12a.

  B: Distance (mm) in the axial direction X between the apex 28a of the first peak portion 28 and the bellows side opening end 18a of the clamp groove 18. That is, the dimension B is the distance in the axial direction X between the end portion of the clamp groove 18 on the bellows portion 16 side and the apex 28a of the first peak portion 28.

  C: The dimension (mm) of the radius of curvature R of the connecting portion 40 having an arcuate cross section connecting the outer slope 28b of the first peak portion 28 and the outer peripheral surface 12a of the small diameter cylindrical portion 12. Here, the outer inclined surface 28b is an inclined surface on the outer surface side of the first peak portion 28 on the small-diameter cylindrical portion 12 side, and is an inclined surface having a linear cross section (thus forming a tapered surface as the entire peripheral shape). It is. Further, the outer peripheral surface 12a of the small diameter cylindrical portion 12 has a linear shape in which the cross section is parallel to the axial direction X on the bellows portion 16 side with respect to the clamp concave groove 18, so that the cylindrical shape has a full peripheral shape. It has a planar shape. Accordingly, the connecting portion 40 is a surface portion having an arcuate cross section that is interposed between the outer inclined surface 28a having the tapered surface shape and the outer peripheral surface 12a of the small-diameter cylindrical portion 12 having the cylindrical surface shape, and connects the two. C is the radius of curvature.

  D: The length of the perpendicular q drawn from the inner slope 28c of the first peak portion 28 to the outer slope 28b with the boundary point P between the connecting portion 40 having the arcuate cross section and the outer slope 28b as a leg. Here, the boundary point P is a point where the connecting portion 40 having a circular arc shape with a radius of curvature R intersects the outer slope 28b, that is, a point located at the end of the connecting portion 40 on the bellows portion 16 side. . The inner inclined surface 28c is an inclined surface on the inner surface side of the first peak portion 28 on the small-diameter cylindrical portion 12 side, and is an inclined surface having a linear cross section (thus forming a tapered surface as the entire peripheral shape). The perpendicular q is a perpendicular drawn from the inner slope 28c to the outer slope 28b so as to intersect perpendicularly at the boundary point P, and its length D is a boundary from the inner slope 28c on the perpendicular q. This is the distance to the point P. Therefore, the dimension D becomes an index of the thickness of the first peak portion 28 at the boundary point P, and particularly corresponds to the thickness of the root portion of the first peak portion 28 on the small diameter cylindrical portion 12 side.

  In the rubber boot 10 of the present embodiment, for these dimensions A to D, (1) B / A ≧ 0.80, (2) C / A ≧ 0.32, and D / A ≧ 0.26 are set. ing.

  Regarding (1), the smaller the dimension A and the larger the dimension B, the easier it is to avoid interference with the caulking convex portion 8a even if the first peak portion 28 falls to the small diameter cylindrical portion 12 side. . Therefore, B / A is preferably as large as possible, and by setting it to 0.80 or more, interference with the caulking convex portion 8a can be avoided. That is, when B / A is less than 0.80, interference between the first peak portion 28 and the caulking convex portion 8a cannot be avoided. B / A is more preferably 1.00 or more. The upper limit of B / A is not particularly limited, but is preferably 1.50 or less in order to satisfy good bellows performance.

  As for C / A in (2) above, the larger this value, the larger the radius of curvature R at the root of the first peak 28 relative to the peak height, and the first peak 28 is closer to the small diameter cylinder 12 side. It becomes difficult to fall into. That is, if the radius of curvature at the base portion is small, the first peak portion 28 tends to fall from that portion as a starting point, but by setting C / A to 0.32 or more, the fall is suppressed. Interference between the first peak portion 28 and the caulking convex portion 8a can be avoided. C / A is more preferably 0.35 or more. The upper limit of C / A is not particularly limited, but is usually preferably 0.75 or less.

  As the D / A of (3) is larger, the thickness at the base portion of the first peak portion 28 with respect to the peak height is larger. When the wall thickness is increased, the rigidity at the base portion is increased, and the first peak portion 28 is unlikely to fall down to the small diameter cylindrical portion 12 side. If D / A is less than 0.26, the thickness of the first peak portion 28 becomes too thin, the rigidity becomes small, and the first peak portion 28 and the caulking convex portion 8a may interfere with each other. D / A is more preferably 0.29 or more. The upper limit of D / A is not particularly limited, but is preferably 0.55 or less in order to satisfy good bellows performance.

  In addition, about the height of the crimping convex part 8a, the protrusion height to the radial direction K from the bellows part side opening end 18a (namely, outer peripheral surface 12a of the small diameter cylindrical part 12) of the clamp ditch | groove 18 is set to E (FIG. 4). As a reference), E / A is usually about 0.50 to 1.10.

  When the present inventors examined the shape of the 1st peak part 28 about various conventional constant velocity joint rubber boots, those which satisfy all the above (1)-(3) do not exist, The configuration satisfying (1) to (3) is a new configuration based on a technical idea different from the conventional one. Table 1 below shows B / A, C / A, and D / A for rubber boots according to Examples 1 to 3 that embody the above-described embodiment and Conventional Examples 1 to 7 that are conventional rubber boot products. Is. In Conventional Examples 1 to 7, at least one of the above (1) to (3) is not satisfied, and the shape is clearly different from that of the present embodiment.

  About each rubber boot of Examples 1-3 and Conventional Examples 1-7, the presence or absence of interference with a caulking convex part and durability were evaluated. For interference with the caulking convex portion, each rubber boot is assembled to the corresponding constant velocity joint, and each constant velocity joint with the vehicle not mounted is slid in the axial direction X in the direction of compressing the boot (−1 mm to − 26mm), and further, the maximum movable angle (12 ° to 31 °) at each slide position, or the constant velocity joint without any angle, the maximum slide position (−19 mm to −36 mm), The presence or absence of interference (contact) between the first peak portion and the caulking convex portion was evaluated.

As for durability, each rubber boot is assembled to the corresponding constant velocity joint and bent at the maximum joint angle and the maximum slide amount of each constant velocity joint in the vehicle mounted state. The number of revolutions was set to 300 rpm, and the time until breakage was measured. The evaluation was made with “◯” for 50 hours or more, and with “x” for those less than that.

  The results are as shown in Table 1, and in Conventional Examples 1 to 7 that do not satisfy at least one of the above (1) to (3), the first peak portion and the caulking convex portion interfere with each other. In the rubber boots of Examples 1 to 3 according to the present embodiment, the interference between the bellows portion and the caulking convex portion can be avoided while satisfying the target durability of the bellows performance.

  In the above embodiment, the bellows part is composed of three peaks and three valleys. However, the number and shape of the peaks and valleys are not limited to those in the above embodiment, and various changes can be made. is there. Although not enumerated one by one, various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 10 ... Rubber boot for constant velocity joints 12 ... Small diameter cylinder part 12a ... Outer peripheral surface 14 ... Large diameter cylinder part 16 ... Bellows part 18 ... Clamp groove 28 ... 1st mountain part 28a ... Apex 28b ... Outer slope 28c ... Inner slope 40 ... Connecting part O ... Axis center K ... Radial direction X ... Axial direction P ... Boundary point (foot of perpendicular) q ... Perpendicular

Claims (2)

A small-diameter cylindrical portion provided with an annular clamping groove on the outer peripheral surface; a large-diameter cylindrical portion spaced from the small-diameter cylindrical portion and arranged coaxially and having a larger diameter than the small-diameter cylindrical portion; and the small-diameter cylindrical portion; A large-diameter cylindrical portion is integrally connected, and a plurality of peak portions and valley portions including a first peak portion, a first valley portion, and a second peak portion are alternately and sequentially arranged from the small-diameter cylindrical portion side. A rubber boot for a constant velocity joint having a bellows part,
In the cross section including the axis of the rubber boot, the radial distance between the apex of the first peak and the bellows side opening end of the clamp recess is A, and the apex of the first peak and the clamp recess The axial distance from the bellows portion side opening end of the groove is B, and the curvature radius of the connecting portion having an arcuate cross section connecting the outer slope of the first peak portion and the outer peripheral surface of the small diameter cylindrical portion is C. And D is a length of a perpendicular line extending from the inner slope of the first peak to the outer slope with the boundary point between the connecting portion and the outer slope as a perpendicular foot, and B / A is 0.80 or more, A rubber boot for a constant velocity joint, wherein C / A is set to 0.32 or more and D / A is set to 0.26 or more.   2. The rubber boot for a constant velocity joint according to claim 1, wherein the clamp clamp mounted in the clamp concave groove is a clamp clamp having a caulking convex portion projecting radially outward at one place in a circumferential direction. .

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