JP2009079700A - Boot for constant velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a boot for a constant velocity universal joint enabling the constant velocity universal joint to take on a high operating angle of 50 degrees or more, without impairing its function and durability. <P>SOLUTION: In a plurality of ridge parts 17 forming a bellows part 16 of the boot 13, a recessed part 25 is formed in a top portion of at least a first ridge part as counted from an outer ring side. A pair of protrusion parts 28, 29 is formed on outer diameter side ends of opposing inner side faces 26, 27 of the recessed part 25, and tips 30, 31 of the protrusion parts 28, 29 are tapered, radially contracting toward a line α bisecting the recessed part in a radial direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a boot for a constant velocity universal joint that is used in a drive shaft of an automobile or various industrial machines and is attached to a constant velocity universal joint that transmits rotational torque.

  The constant velocity universal joint boot has a function to prevent the leakage of lubricating components such as grease and lubricating oil enclosed in the constant velocity universal joint (inside the joint) and the entry of foreign matter from the outside into the joint. Fulfill.

  As a constant velocity universal joint to which such a constant velocity universal joint boot (hereinafter abbreviated as a boot) is attached, FIG. 11 shows an undercut free constant velocity universal joint (UJ) which is one of the fixed type constant velocity universal joints. ).

  The constant velocity universal joint 101 includes an outer ring 102, an inner ring 103, a ball 104, and a cage 105 as main parts. Inside the outer ring 102, an internal part 106 including the inner ring 103, the ball 104, and the cage 105 is accommodated. ing.

  The outer ring 102 has an opening at one end, and a plurality of track grooves 107 are formed on the inner peripheral surface. A plurality of track grooves 108 are formed on the outer peripheral surface of the inner ring 103, and a shaft 110 is spline-fitted into the center hole 109 and is prevented from coming off by a circular circlip 111. A plurality of balls 104 are interposed between the track grooves 107 of the outer ring 102 and the track grooves 108 of the inner ring 103, and these balls 104 are held in a pocket 112 of the cage 105 disposed between the outer ring 102 and the inner ring 103. Has been.

Now, the opening of the outer ring 102 is covered with the boot 113 already described. The boot 113 includes a large diameter end portion 114, a small diameter end portion 115, and a bellows portion 116 that connects the large diameter end portion 114 and the small diameter end portion 115. The bellows portion 116 is formed by alternately forming a plurality of peak portions 117 and valley portions 118 each having a diameter reduced from the large-diameter end portion side toward the small-diameter end portion side. The large-diameter end portion 114 is attached to the outer peripheral surface 120 of the open end portion 119 of the outer ring 102, and the small-diameter end portion 115 is attached to the outer peripheral surface 123 of the shaft 110. Each attachment portion adds a boot band (121, 122). It is fastened and fixed (see Patent Document 1).
JP 2007-155002 A

  Now, in the constant velocity universal joint described in Patent Document 1 shown in FIG. 11, when the bellows portion 116 of the boot 113 is bent at a high operating angle of 50 ° or more, the bellows portion 116 has a peak portion on the side opposite to the bending direction. 117 (particularly on the large-diameter end portion side) extends and the apex portion thereof is recessed, so that there is a problem that the flexibility of the boot 113 is lowered and the life is shortened.

  As a method for solving this problem, a method is considered in which the boot 113 is easily elastically deformed by increasing the film length of the bellows portion 116 of the boot 113 (the length along the cross-sectional shape in the axial direction). As described above, as a method of increasing the film length of the bellows portion 116, it is conceivable to increase the outer diameter of the peak portion 117 or to decrease the inner diameter of the valley portion 118.

  However, if the inner diameter of the valley portion 118 is reduced, there is a problem that when the constant velocity universal joint 101 takes an operating angle, the valley portion 118 interferes with the shaft 110 and wears, which reduces the durability of the boot 113. It leads to. Further, when the outer diameter of the peak portion 117 is increased, the outer diameter of the bellows portion 116 is increased. Therefore, when the constant velocity universal joint 101 rotates, the centrifugal force applied to the boot 113 increases, and the centrifugal force causes the trough portion. 118 expands (the rotational expansion property of the boot 113 deteriorates), thereby reducing the difference between the outer diameter of the crest 117 and the inner diameter of the trough 118 and eliminating the crest of the bellows 116, thereby making the boot 113 flexible. There was a risk of losing its properties and impairing its functions.

  The present invention has been made in view of the above circumstances, and impairs the function and durability of a constant velocity universal joint boot that allows the constant velocity universal joint to take a high operating angle of 50 ° or more. It aims to provide without.

  The boot for a constant velocity universal joint according to the present invention for solving the above-mentioned problems is a shaft member having one end attached to an outer joint member of the constant velocity universal joint and the other end extended from the opening of the outer joint member. A constant velocity universal joint boot having a bellows portion formed by connecting the one end portion and the other end portion and having a plurality of peak portions and trough portions alternately formed, the bellows portion Among the ridges, at least the top portion of the first ridge located on the outer joint member side is formed with an annular recess for preventing a dent when the constant velocity universal joint takes an operating angle. .

  When the constant velocity universal joint takes an operating angle and the bellows portion of the boot bends, the peak portion on the outer joint member side extends in the axial direction on the anti-bending direction side of the bellows portion, and the top portion tends to be recessed. This is particularly noticeable on the large-diameter end portion side of the bellows portion. Therefore, when the concave portion is formed at least at the top portion of the first peak portion (the first peak portion counted from the outer joint member side) as in the present invention, the constant velocity universal joint takes an operating angle and the bellows of the boot. Even if the portion is bent and at least the top portion of the first peak portion is recessed on the anti-bending direction side of the bellows portion, this action can be suppressed by the concave portion formed at the top portion of the first peak portion.

  Moreover, it is preferable to form the said recessed part also in the top part of the 2nd peak part located in an outer joint member side among the peak parts of the said bellows part.

  As already mentioned, when the constant velocity universal joint takes an operating angle and the bellows part of the boot bends, the peak part on the outer joint member side extends in the axial direction on the anti-bending direction side of the bellows part, and its top part Is easy to dent. However, in addition to the first peak portion described above, if a concave portion is also provided at the top portion of the second peak portion, the constant velocity universal joint takes a high operating angle and the boot bellows portion is bent greatly, and the bellows portion is bent. Even if the top portions of the first peak portion and the second peak portion are recessed on the bending direction side, this action can be suppressed by the concave portions formed in the top portions of the first peak portion and the second peak portion. Therefore, the dent resistance on the outer joint member side of the bellows portion is greatly improved, and as a result, the constant velocity universal joint can reliably take a high operating angle.

  In addition, it is desirable to provide a pair of projecting portions that are in contact with each other in order to suppress wear on the bending direction side when the joint takes an operating angle on the opposing inner surface of the recess.

  When the constant velocity universal joint takes an operating angle and the bellows portion of the boot bends, at least the first peak portion contracts on the bending direction side of the bellows portion, and the opposing inner side surfaces of the recesses formed at the apex portion mutually Try to contact. However, by providing a pair of protrusions on the opposite inner surface of the recess as in the present invention, when the constant velocity universal joint takes an operating angle and the bellows portion of the boot is bent, on the bending direction side of the bellows portion, Since the pair of projecting portions provided on the opposing inner surface of the recess formed at least at the top portion of the first peak portion contact each other, it is possible to prevent the opposing inner surface of the recess from directly contacting and wearing. .

  It is preferable that the pair of projecting portions be provided on the outer diameter side end portion of the opposed inner surface of the recess.

  When the constant velocity universal joint takes an operating angle and the bellows portion of the boot bends, at least the first peak portion contracts on the bending direction side of the bellows portion, and the opposing inner side surfaces of the recesses formed at the apex portion mutually Try to contact. This is particularly noticeable on the opposed inner surface of the outer diameter side end of the recess. The reason for this is that when the bellows part is bent, the outer diameter side end part contacts the earliest side of the opposing inner surface of the recess, so the contact frequency when the constant velocity universal joint takes an operating angle is the opposing inner surface of the recess. This is because the contact wear is likely to occur. Therefore, as in the present invention, the provision of a pair of protrusions on the outer diameter side end of the opposed inner surface of the recess means that the contact wear of at least the opposed inner surface of the first peak portion is on the bending direction side of the bellows portion. It is effective as a means for efficiently preventing the above.

  It is desirable that the opposed tip portions of the pair of projecting portions have a planar shape.

  Here, the “front end portion of the projecting portion” means that when the constant velocity universal joint takes an operating angle and the bellows portion of the boot is bent, at least the first peak portion on the bending direction side of the bellows portion. It means a portion of the pair of projecting portions provided in the formed recess that contact each other. As in the present invention, since the contact portion of the projecting portion (the tip portion of the projecting portion) is planar, the contact area at the tip portion of the projecting portion is increased. At the peak, it is possible to prevent contact wear on the opposite inner surface of the concave portion formed at the top portion, and to disperse the force received at the time of contact at the planar tip to improve the durability of the protrusion itself Can do.

  The pair of protrusions are preferably provided by integral molding with the boot.

  In this way, by providing the projecting portion by integral formation with the boot, it is not necessary to use another component as the projecting portion, so that the number of components can be reduced. Therefore, it is possible to reduce the manufacturing cost necessary for manufacturing the boot.

  In the boot for a constant velocity universal joint according to the present invention, a concave portion is formed at least at the top portion of the first peak portion on the outer joint member side in the bellows portion. In this case, even if the constant velocity universal joint takes a high operating angle and the bellows portion of the boot is bent greatly, it is possible to prevent at least the top portion of the first peak portion from being recessed on the anti-bending direction side of the bellows portion. The bendability of the bellows portion on the outer joint member side can be improved. As a result, the constant velocity universal joint to which the boot of the present invention is attached can take a high operating angle. In the present invention, the boot membrane length is not increased by increasing the inner diameter of the peak or reducing the inner diameter of the valley unlike the conventional boot shown in FIG. The function and durability of the camera are not impaired.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 5 shows, as a first embodiment of the present invention, a constant velocity universal joint equipped with the constant velocity universal joint boot of the present invention.

  This constant velocity universal joint 1 is an undercut free type constant velocity universal joint (UJ) which is one of fixed type constant velocity universal joints, an outer ring 2 which is an outer joint member, an inner ring 3 which is an inner joint member, a ball 4. The cage 5 is the main part. Inside the outer ring 2, an internal part 6 including an inner ring 3, a ball 4 and a cage 5 is accommodated.

  The outer ring 2 has an opening at one end, and a plurality of track grooves 7 are formed on the inner peripheral surface. A plurality of track grooves 8 are formed on the outer peripheral surface of the inner ring 3, and a shaft 10 is spline-fitted into the center hole 9 from the opening of the outer ring 2. The shaft 10 is pulled out by a circular circlip 11 interposed between a concave groove 23 formed on the outer peripheral surface of the end portion and an annular concave groove 34 formed at the end portion of the center hole 9 of the inner ring 3. It has been stopped. A plurality of balls 4 are interposed between the track grooves 7 of the outer ring 2 and the track grooves 8 of the inner ring 3, and these balls 4 are held in a pocket 12 of the cage 5 disposed between the outer ring 2 and the inner ring 3. Has been.

  The opening of the outer ring 2 is covered with a boot 13. The boot 13 has a large-diameter end portion 14 that is one end portion, a small-diameter end portion 15 that is the other end portion, and a bellows portion 16 that connects the large-diameter end portion 14 and the small-diameter end portion 15. The bellows portion 16 is formed by alternately forming a plurality of crest portions 17 and trough portions 18 each having a diameter reduced from the large-diameter end portion side toward the small-diameter end portion side. The large-diameter end portion 14 is attached to the outer peripheral surface 20 of the open end portion 19 of the outer ring 2, and the small-diameter end portion 15 is attached to the outer peripheral surface 32 of the shaft 10, and each attachment portion adds a boot band (21, 22). Tightened and fixed.

Now, in this embodiment, as shown in FIG. 3 which is an enlarged view of the X ₁ portion of FIG. 5 and FIG. 1 which is an enlarged view of the X ₂ portion of FIG. A concave portion 25 is formed in an annular shape at the top portion of the first peak portion 24 (first peak portion 17 counted from the outer ring side) located on the side. The recess 25 includes a bottom 33 and a pair of opposed inner surfaces (26, 27) extending in the outer diameter direction from both axial sides of the bottom 33.

When the constant velocity universal joint 1 has a high operating angle of 50 ° or more in the direction indicated by the white arrow in FIG. 5 and the bellows portion 16 of the boot 13 is bent in the same direction, the anti-bending direction of the bellows portion 16 in the side (opposite side to the white arrow direction in the drawing), the first crest portion 24 (portion enclosed by a drawing X ₁₎ is extended as shown in FIG. 4, when you Hekomo at its top portion Force acts. However, when the concave portion 25 is provided in the top portion of the first peak portion 24 as in the present embodiment, the concave portion 25 suppresses the action of trying to concave the top portion of the first peak portion 24, so the first peak portion 24 does not dent. Therefore, the flexibility (easy to bend) of the bellows portion 16 on the outer ring side is improved. As a result, the constant velocity universal joint 1 can take a high operating angle of 50 ° or more.

  In addition, a pair of projecting portions (28, 29) are provided by integral molding with the boot 13 at the outer diameter side end portion of the opposed inner surface (26, 27) of the concave portion 25 formed in the first peak portion 24, The tip portions (30, 31) of the projecting portions (28, 29) facing each other are tapered surfaces whose diameter is reduced toward a line (indicated by α in the figure) that bisects the concave portion 25 in the axial direction. .

When the constant velocity universal joint 1 takes an operating angle in the direction indicated by the white arrow in FIG. 5 and the bellows portion 16 of the boot 13 bends in the same direction, the bending direction side of the bellows portion 16 (white in the drawing) the first crest portion 24 of the arrow direction side) (portion enclosed by a drawing X ₂₎ is contracted as shown in FIG. 2, opposite the side face of the recess 25 (26, 27) attempts to contact. However, when the pair of projecting portions (28, 29) are provided on the opposing inner side surfaces (26, 27) of the recess 25 as in the present embodiment, even if the opposing inner side surfaces (26, 27) try to contact each other. The tip portions (30, 31) of the pair of projecting portions (28, 29) provided on this contact first. Thus, when the front-end | tip part (30, 31) of a protruding part (28, 29) mutually contacts, it can prevent that an opposing inner surface (26, 27) mutually contacts and wears.

  Further, the contact portions of the projecting portions (28, 29), that is, the tip portions (30, 31) of the projecting portions (28, 29) have the recesses 25 in the axial direction as shown in FIGS. In order to form a tapered surface whose diameter is reduced toward a bisecting line (α in the figure), the projecting portions (28, 29) have a force at the time of contact even if the tip portions (30, 31) contact each other. Is dispersed by surface contact between the tapered surfaces, the durability of the protrusions (28, 29) can be improved.

  Further, since the projecting portions (28, 29) are provided integrally with the boot 13, it is not necessary to use a separate part as the projecting portion. For this reason, the number of parts can be reduced, and the cost required for manufacturing the boot 13 can be reduced. In this embodiment, the film length of the bellows portion 16 of the boot 13 is set such that the outer diameter of the peak portion 17 is increased or the inner diameter of the valley portion 18 is decreased as in the conventional boot shown in FIG. Therefore, the function and durability of the boot 13 are not impaired.

  FIG. 6 shows a fixed type constant velocity universal joint 41 (UJ) as a second embodiment of the present invention. In this embodiment, parts having the same portions, functions, and forms as those in the first embodiment shown in FIG. 5 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the constant velocity universal joint 41, the opening of the outer ring 2 is covered with a boot 43. The boot 43 includes a large-diameter end 44 that is one end, a small-diameter end 45 that is the other end, and a large-diameter end. The bellows portion 46 has a plurality of peak portions 47 and valley portions 48 that each reduce in diameter from the large diameter end portion side toward the small diameter end portion side. Formed. A large-diameter end 44 is attached to the outer peripheral surface 20 of the open end 19 of the outer ring 2, and a small-diameter end 45 is attached to the outer peripheral surface 32 of the shaft 10, and the respective attachment portions are boot bands (21, 22). It is fixed by crimping.

In the present embodiment, as shown in FIG. 9 which is an enlarged view of the Y ₁ portion of FIG. 6 and FIG. 7 which is an enlarged view of the Y ₂ portion of FIG. 6, the first peak portion 54 of the boot 43 (counted from the outer ring side). Recesses (55, 64) are formed in the top portions of the first peak portion 47) and the second peak portion 63 (second peak portion 47 counted from the outer ring side), respectively. The recesses (55, 64) include a bottom portion (62, 67) and opposing inner side surfaces (56, 57 and 65, 66) extending in the outer diameter direction from both axial sides of the bottom portion (62, 67).

When the constant velocity universal joint 41 has a high operating angle of 50 ° or more in the direction indicated by the white arrow in FIG. 6 and the bellows portion 46 of the boot 43 is largely bent in the direction of the white arrow in the drawing, the bellows portion 46. The first peak portion 54 and the second peak portion 63 (the portion surrounded by Y ₁ in the figure) on the side opposite to the bending direction (the side opposite to the white arrow direction side in the figure) extend as shown in FIG. Thus, a force to dent is applied to the apex portion. However, when the concave portions (55, 64) are provided in the first mountain portion 54 and the second mountain portion 63 as in the present embodiment, the concave portions (55, 64) are formed in the first mountain portion 24 and the second mountain portion described above. In order to suppress the action of trying to dent the top portion of the portion 63, the first ridge portion 24 and the second ridge portion 63 are not recessed. Therefore, the bendability (easy to bend) of the bellows portion 46 on the outer ring side is greatly improved, and moreover, this action becomes more remarkable than the first embodiment shown in FIG. As a result, the constant velocity universal joint 41 can reliably take a high operating angle of 50 ° or more.

  In the present embodiment, a pair of projecting portions (58, 59 and 68, 69) are integrally formed with the boot 43 on the opposite inner side surfaces (56, 57 and 65, 66) of the recesses (55, 64). The opposite tip portions (60, 61 and 70, 71) of the projecting portion are tapered toward the line (indicated by β in the figure) that bisects the recesses (55, 64) in the axial direction. A surface.

When the constant velocity universal joint 41 takes an operating angle and the boot 43 is bent as shown by a white arrow in FIG. 6, the first peak portion 54 on the bending direction side (the white arrow direction side in the drawing) of the boot 43. The second peak 63 (the portion surrounded by Y ₂ in the figure) contracts as shown in FIG. 8 so that the opposing inner surfaces (56, 57 and 65, 66) of the recesses (55, 64) come into contact with each other. And However, when the pair of protrusions (58, 59 and 68, 69) are provided on the opposing inner side surfaces (56, 57 and 65, 66) of the recesses (55, 64) as in the present embodiment, Even if the side surfaces (56, 57 and 65, 66) try to contact each other, the tip portions (60, 61 and 70, 71) of the pair of protrusions (58, 59 and 68, 69) provided on the side surfaces contact each other. To do. In this way, the tip end portions (60, 61 and 70, 71) of the projecting portions (58, 59 and 68, 69) come into contact with each other, so that the opposing inner surface (26, 27) of the recess (55, 64). Can be prevented from coming into contact with each other and being worn.

  The contact portions of the projecting portions (58, 59 and 68, 69), that is, the tip portions (60, 61 and 70, 71) of the projecting portions (58, 59 and 68, 69) are shown in FIGS. As shown in FIG. 9, since the concave portion 25 has a tapered surface that is reduced in diameter toward a line (β in the figure) that is bisected in the axial direction, the protrusions (58, 59 and 68, 69) Even if (60, 61 and 70, 71) come into contact with each other, the force at the time of contact is dispersed by the surface contact between the tapered surfaces, so the durability of the protrusions (58, 59 and 68, 69) is improved. Can be made.

  Since the protrusions (58, 59 and 68, 69) are provided by integral molding with the boot 43, it is not necessary to use a separate part as the protrusion, and thus the manufacturing cost required for manufacturing the boot 43 is eliminated. Can be reduced. Also in this embodiment, the film length of the bellows portion 46 of the boot 43 is set such that the outer diameter of the peak portion 47 is increased or the inner diameter of the valley portion 48 is decreased as in the conventional boot shown in FIG. Therefore, the function and durability of the boot 43 are not impaired.

  Although the embodiments of the present invention have been described so far, the present invention is not limited thereto, and various modifications can be made without departing from the meaning and contents described in the claims.

  For example, in the embodiment mentioned here, a pair of protrusions are provided on the outer diameter side end portions of the opposing inner surface of the concave portions formed in the first peak portion and the second peak portion. The arrangement position on the inner surface is not limited to the outer diameter side end, and can be arbitrarily changed as long as the effect of the present invention of preventing contact wear on the opposed inner surface can be obtained.

  In the embodiment described here, the present invention is applied to a resin boot. However, the present invention can also be applied to a CR (chloroprene rubber) boot. And the boot for constant velocity universal joints of this invention can be applied not only to the fixed type constant velocity universal joint mentioned in the embodiment but also to a known sliding type constant velocity universal joint.

  Furthermore, the bellows portion of the boot of the present embodiment has a shape in which a plurality of peak portions and valley portions are each reduced in diameter from the large diameter end portion side toward the small diameter end portion side. The present invention can also be applied to a boot that is constant from the end side to the small-diameter end side, and the small-diameter end of the boot is attached to a connecting component (such as a metal plate) attached to the outer peripheral surface of the shaft. Also, the present invention can be applied.

FIG. 6 is an enlarged view of a portion X ₂ in FIG. 5. First crest portion of X ₂ portion shown in FIG. 5 is a sectional view showing a state in which contracted. FIG. 6 is an enlarged view of a portion X ₁ in FIG. 5. It is a sectional view showing a state where the first crest portion of X ₁ part shown is extended in FIG. It is sectional drawing which shows the 1st Embodiment of this invention. It is sectional drawing which shows the 2nd Embodiment of this invention. It is an enlarged view of a Y ₂ parts in FIG. The first crest portion and the second convex portion of the Y ₂ portion shown in FIG. 6 is a sectional view showing a state in which contracted. It is an enlarged view of a Y ₁ portion in FIG. Is a sectional view showing a first crest portion and the state in which the second convex portion is extended in the Y ₁ portion shown in FIG 6 It is sectional drawing which shows the constant velocity universal joint equipped with the boot for conventional constant velocity universal joints.

Explanation of symbols

1 Fixed type constant velocity universal joint (UJ)
2 Outer ring (outer joint member)
10 Shaft (other parts)
13, 43 Boots 14, 44 Large diameter end (one end)
15, 45 Small diameter end (other end)
16, 46 Bellows portion 17, 47 Mountain portion 18, 48 Valley portion 24, 54 First mountain portion 63 Second mountain portion 25, 55, 64 Recessed portions 26, 27, 56, 57, 65, 66 Opposing inner side surfaces 28, 29 , 58, 59, 68, 69 Protruding part 30, 31, 60, 61, 70, 71 Tip part (tapered surface)

Claims (6)

One end is attached to the outer joint member of the constant velocity universal joint, the other end is attached to the shaft member extending from the opening of the outer joint member, and connects the one end and the other end; and A constant velocity universal joint boot having a bellows part formed by alternately forming a plurality of peaks and valleys,
Of the ridges of the bellows part, at least the top part of the first ridge part located on the outer joint member side is formed with a recess to prevent a dent when the constant velocity universal joint takes an operating angle. A boot for constant velocity universal joints.   2. The constant velocity universal joint boot according to claim 1, wherein the concave portion is formed at a top portion of a second peak portion located on the outer joint member side.   3. The constant velocity universal joint boot according to claim 1, wherein a pair of projecting portions that come into contact with each other when the joint takes an operating angle are provided on the opposing inner surface of the concave portion.   4. The constant velocity universal joint boot according to claim 3, wherein the pair of projecting portions are provided on an outer diameter side end portion of an opposed inner surface of the concave portion.   5. The constant velocity universal joint boot according to claim 3, wherein the opposing tip portions of the pair of projecting portions are planar.   The constant-velocity universal joint boot according to any one of claims 3 to 5, wherein the pair of projecting portions are provided by integral molding with the boot.

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