JP2015113879A - Boot for constant velocity joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a boot for a constant velocity joint capable of suppressing generation of rubbing sound from a bellows portion of the boot in operating the constant velocity joint.SOLUTION: A boot 70 for a constant velocity joint has a bellows portion 71 in which crest portions 71a-71f and trough portions 71g-71k are alternately and continuously formed. Grooves 74 and 75 for discharging a fluid from a bottom side toward a crest portion side, are formed on an outer peripheral face Ga which connects apex portions T of the crest portions and bottoms Bo of the trough portions.

Description

  The present invention relates to a constant velocity joint boot.

  Conventionally, there is a boot that is mounted between two members and enables an operation that follows the relative movement of the two members. By the way, in recent years, a boot for a constant velocity joint among such boots has been requested to be downsized, and in order to realize downsizing, for example, it is necessary to shorten the overall length of the boot. In this case, in order to satisfy a large operating angle of the constant velocity joint, as shown in Patent Document 1, many ridges and valleys must be formed continuously in a short overall length. As a result, when the constant velocity joint is bent and operated at a large operating angle, the crests and troughs extend outside the bent part, and the necessary length can be ensured.

JP 2005-83439 A

  However, the downsized constant velocity joint boot described above has many peaks and valleys continuously. For this reason, when the constant velocity joint is bent and operated at a large operating angle, the bellows folds and contracts at the contracted portion inside the bent portion, and the adjacent outer peripheral surfaces of the mountain portions contact each other and are relatively displaced. May rub against each other. At this time, for example, if water adheres to the outer peripheral surface of each adjacent peak, the outer peripheral surfaces stick-slip due to non-uniform friction coefficient between the water adhering part and the non-adhering part, As a result, there is a risk of scratching.

  This invention is made in view of such a situation, and it aims at providing the boot for constant velocity joints which can suppress generation | occurrence | production of the abrasion noise from the bellows part of the boot at the time of constant velocity joint operation | movement. .

  (Claim 1) The constant velocity joint boot of the present invention is a constant velocity joint boot having bellows portions formed by alternately and continuously forming peaks and troughs, and the top of the peaks and the A groove for discharging the fluid from the valley bottom side toward the peak side is provided on the outer peripheral surface connecting the valley bottom.

  As a result, when a fluid such as water adheres to the outer peripheral surface, when the constant velocity joint is operated in a bent state, each contacted outer peripheral surface is the outer peripheral surface in a portion where the bellows portion is contracted. The fluid adhering to the surface is pushed out and moved into the groove. And the fluid which flowed into the groove | channel distribute | circulates a groove | channel by the centrifugal force which generate | occur | produced with rotation of a bellows part, and is discharged | emitted outside the bellows part. For this reason, the friction coefficient between the outer peripheral surfaces which contact is uniform, and generation | occurrence | production of the abrasion sound resulting from a stick slip is suppressed.

  (Claim 2) In the state where the opposing outer peripheral surfaces connecting the apex of the adjacent peak portions and the valley bottom of the valley portion located between the peak portions are in contact with each other, the groove is radially outward. You may form so that it may open. Thus, the same effect as in the first aspect can be obtained with certainty.

  (Claim 3) The constant velocity joint boot is provided with a plurality of grooves, and the plurality of grooves are formed radially outward from a center line of the constant velocity joint boot. May be. Thus, when each contacted outer peripheral surface pushes out the fluid adhering to the outer peripheral surface, it can be reliably collected in the groove in a short time when the extruded fluid moves in the circumferential direction of each outer peripheral surface.

  (Claim 4) The groove may be formed so that a cross-sectional area of the channel is enlarged from the valley bottom side toward the peak portion side. As a result, the fluid that has flowed into the groove can flow out to the outside without resistance, and the fluid between the outer peripheral surfaces can be discharged well.

  (Claim 5) The groove is provided on one outer peripheral surface of the opposing outer peripheral surface respectively connecting the apex of the adjacent peak portions and the valley bottom located between the peak portions, and the other of the opposing outer peripheral surfaces. The outer peripheral surface may be formed in a non-recessed shape. Thereby, it is not necessary to provide a groove on both sides of the opposing outer peripheral surface, and it can be formed at low cost.

  (Claim 6) The distance from the valley bottom to the peak on one of the opposing outer peripheral surfaces is shorter than the distance from the valley bottom to the peak on the other of the opposing outer peripheral surfaces, and the groove is the counter outer peripheral surface. It may be provided in one of these. Thereby, the fluid that has flowed into the groove flows through the short groove by the centrifugal force generated with the rotation of the bellows part, and is discharged to the outside of the bellows part in a short time.

It is a figure explaining the state when operating the constant velocity joint assembly by the predetermined operating angle. FIG. 5 is an enlarged view illustrating the boot in an initial state where the constant velocity joint assembly is not operated at a predetermined operating angle. It is the Q section enlarged view of FIG. FIG. 4 is a sectional view taken along arrow 4-4 in FIG. 3. FIG. 5 is an enlarged cross-sectional view taken along arrow 5-5 in FIG. 4. It is a figure explaining the groove shape of the deformation | transformation aspect corresponding to FIG.

<Embodiment>
(Constitution of constant velocity joint assembly)
The constant velocity joint assembly 1 of the present embodiment will be described with reference mainly to FIGS. FIG. 1 is an axial cross-sectional view showing a state where the constant velocity joint assembly 1 is operated at the maximum joint angle θ. FIG. 2 shows an axial sectional view of the boot of FIG. 1 in the initial state. FIG. 3 is an enlarged view of a portion Q in FIG. Here, the initial state is a state where the joint angle is 0 °. The joint angle is a relative angle between the outer ring axis C1 and the inner ring axis C2 shown in FIG. The maximum joint angle refers to a joint angle at which the opening end of the outer ring and the outer peripheral surface of the shaft are in contact with each other and a further angle cannot be added. Normally, the constant velocity joint 10 is operated at an angle below the maximum joint angle θ.

  The constant velocity joint assembly 1 is used for a power transmission shaft of a vehicle, for example. The constant velocity joint assembly 1 is suitably used for a drive shaft that connects a differential (not shown) and a wheel (not shown).

  As shown in FIG. 1, the constant velocity joint assembly 1 includes a constant velocity joint 10, a shaft 60, a constant velocity joint boot 70 (hereinafter referred to as a boot), a large diameter boot band 95, and a small diameter boot band. 96.

  The constant velocity joint 10 is exemplified by a ball type constant velocity joint in FIG. 1, but a tripod type constant velocity joint or the like can also be applied. The constant velocity joint 10 of the present embodiment is a fixed ball type constant velocity joint (also referred to as a “Zepper type constant velocity joint”) that fixes the joint center O as the center of bending and does not allow axial displacement. As shown in FIG. 1, the joint center O is an intersection of the outer ring axis C1 and the inner ring axis C2.

  The constant velocity joint 10 includes an outer ring 20, an inner ring 30 as an inner member, a plurality of balls 40 as torque transmission members, and a cage 50. When a tripod type constant velocity joint is applied, the inner member is a tripod and the torque transmission member is a roller.

  The shaft 60 includes a front end portion 61 and a rear portion 62 in order from the front end side (the right side in FIG. 1). The tip portion 61 is spline-fitted with the inner peripheral surface of the inner ring 30. As shown in FIG. 1, when the shaft 60 is inclined at the maximum joint angle θ with respect to the outer ring 20, the rear part 62 contacts the outer peripheral surface of the rear part 62 and the chamfered part 25 a of the open end 25 of the outer ring 20. . In addition, an annular groove 62 a is formed at the left end of the rear part 62 in FIG.

  As shown in FIG. 2, the boot 70 is formed in a cylindrical shape having an inclination as an overall shape, and covers the space between the outer ring 20 and the shaft 60. The boot 70 is made of resin, and includes a bellows portion 71, an outer ring side mounting portion 72, a shaft side mounting portion 73, and a drainage groove 74 (corresponding to the groove of the present invention) formed in the bellows portion 71. Have.

  The bellows portion 71 is provided with a plurality of alternating crests and troughs, is expandable and contractible in the direction of the center line of the boot 70, and bends and deforms to follow changes in the joint angle θ. The center line direction of the boot 70 refers to the center line direction of the boot 70 in the initial state shown in FIG. 2, and coincides with the inner ring axis C2.

  Here, in order from the side close to the opening end 25 of the outer ring 20, reference numerals 71a to 71f are assigned to the six peak parts, and reference numerals 71g to 71k are assigned to the five valley parts located between the peak parts 71a to 71f. Is attached. An outer ring side mounting portion 72 is provided on the right side of the bellows portion 71 in FIG. 1, and a shaft side mounting portion 73 is provided on the left side in FIG. The bellows portion 71 is formed so that the outer diameter of each of the peak portions 71a to 71f is gradually reduced from the outer ring side mounting portion 72 side toward the shaft side mounting portion 73 side.

  The outer ring side attachment portion 72 is attached to the annular groove 24 formed at the outer peripheral surface end portion of the outer ring 20, and is pressed against the outer peripheral surface of the outer ring 20 by pressing the outer peripheral surface radially inward by the large-diameter boot band 95. Seal between. The shaft side attaching portion 73 is attached to the annular groove 62 a of the rear portion 62 of the shaft 60, and seals between the outer peripheral surface of the shaft 60 by pressing the outer peripheral surface radially inward by the small-diameter boot band 96. As the large-diameter boot band 95 and the small-diameter boot band 96, for example, an Ω-type boot band, a folded (one-touch) boot band, or the like is applied.

(Description of the deformation state of the bellows portion 71 when the constant velocity joint 10 is operated)
Here, the deformation state of the bellows portion 71 when the constant velocity joint 10 is operated, which is necessary for the following description, will be described. As described above, the constant velocity joint 10 normally rotates in a state bent at a predetermined joint angle below the maximum joint angle θ shown in FIG. 1. The deformation state will be described with reference to FIG. 1 showing the state.

  In this state, the bellows portion 71 simultaneously has a contraction portion on the contraction side shown in the lower part of FIG. 1 and an extension portion on the extension side shown in the upper part. In the contracted portion, the peak portions 71a to 71f and the valley portions 71g to 71k of the bellows portion 71 are folded and contracted. In the extension part, the peak parts 71a to 71f and the valley parts 71g to 71k extend to ensure the necessary length during extension. When the connecting shaft 21 connected to the outer ring 20 and the shaft 60 are rotated in such a state, the contraction part eventually becomes an extension part at an extension side position rotated 180 degrees, and the extension part is a contraction side position rotated 180 degrees. It becomes a shrinking part. As described above, the bellows portion 71 performs an operation in which the contraction portion and the extension portion repeatedly appear every 180 degrees as the constant velocity joint 10 rotates. Note that the bellows portion 71 is in a state similar to the initial state in an intermediate phase between the extension portion and the contraction portion.

(Detailed configuration of bellows portion 71 and drainage groove 74)
The bellows portion 71 is disposed between the outer ring side mounting portion 72 and the shaft side mounting portion 73. As described above, the bellows portion 71 is formed such that the peak portions 71a to 71f and the valley portions 71g to 71k are alternately and continuously formed. Moreover, each outer peripheral surface Ga is formed between the vertex T of each peak part 71a-71f and the valley bottom Bo of each valley part 71g-71k.

  One outer peripheral surface of the outer peripheral surfaces Ga facing each other between the adjacent peak portions 71a to 71f among the outer peripheral surfaces Ga formed by connecting the respective peak portions 71a to 71f and the respective valley portions 71g to 71k. In Ga, drain grooves 74 shown in FIGS. 3 and 4 are formed. At this time, one outer peripheral surface Ga refers to the outer peripheral surface Ga having a shorter distance from the valley bottom Bo to the apex T of the peak portion among the opposing outer peripheral surfaces Ga (hereinafter also referred to as the opposing outer peripheral surface Ga). I mean. Specifically, in the present embodiment, as shown in FIG. 2, the outer peripheral surface Ga arranged on the outer ring side attachment portion 72 side in the opposed outer peripheral surface Ga is referred to. In this case, the surface of the other outer peripheral surface Ga opposite to the one outer peripheral surface Ga is formed in a non-recessed shape.

  The drainage grooves 74 (grooves) are formed radially from the valley Bo side of each outer peripheral surface Ga toward the peaks 71a to 71f, with the center line of the boot 70 as the center. A plurality of drain grooves 74 are arranged at equal intervals over the entire circumference of each outer peripheral surface Ga. The number to be arranged may be set arbitrarily. Further, as shown in FIG. 4, the groove width of the drainage groove 74 is increased from the valley bottom Bo side toward the peak portions 71a to 71f. In other words, a and b have a relationship of a <b, where a is the groove width on each valley bottom Bo side of each drainage groove 74 and b is the groove width on each mountain portion 71a to 71f side.

  Moreover, the groove depth from each outer peripheral surface Ga of the drain groove 74 is formed at a uniform predetermined depth, and its cross-sectional shape is as shown in FIG. From these, it can be said that in the drainage groove 74, the flow path cross-sectional area A shown in FIG. 5 is gradually enlarged from the valley bottom Bo side toward the peak portions 71a to 71f. In addition, the drainage groove 74 is a bellows no matter how the one outer peripheral surface Ga formed with the drainage groove 74 and the other outer peripheral surface Ga formed in a non-concave shape come into contact with each other in the contracted portion. It is formed so as to open to the outside of the portion 71.

(About the state in the contraction part inside the bending part of the bellows part 71)
During the operation of the constant velocity joint assembly 1 bent at a predetermined joint angle, the outer periphery of each peak portion 71a to 71f of the bellows portion 71 at the contraction portion of the bellows portion 71 inside the bent portion of the constant velocity joint 10. The surfaces come into contact with each other and are folded as shown in FIG.

  At this time, in the bellows portion 71 according to the present embodiment, the outer diameters of the plurality of peak portions 71a to 71f are formed with different outer diameters, similarly to the conventional constant velocity joint boot. For this reason, in the shrinkage | contraction part, each outer peripheral surface Ga of each adjacent peak part 71a-71f contacts, and depending on the contact state, each peak part 71a-71f may contact.

  When each peak part 71a-71f contacts, the peripheral speed at the time of rotating with the action | operation of the constant velocity joint 10 differs in each peak part 71a-71f vicinity. For this reason, there is a case in which a peripheral speed difference occurs between the two in contact with each other, a relative displacement (slip) occurs between the outer peripheral surfaces Ga in the vicinity of the ridges 71a to 71f, and scratching noise is generated between the opposing outer peripheral surfaces Ga. is there. In the present invention, this rubbing sound is allowed.

  However, in such a state, when water (corresponding to the fluid of the present invention) is interposed in a portion between the opposed outer peripheral surfaces Ga that are relatively displaced, a portion where water is attached and a portion where water is not attached The coefficient of friction becomes nonuniform between the two. For this reason, for example, in a conventional constant velocity joint boot in which the opposing outer peripheral surfaces Ga are formed uniformly and non-recessed, when such a state occurs, a well-known stick is formed between the opposing outer peripheral surfaces Ga. It has been found that there is a possibility of slipping and generating a larger scratching sound. An object of the present invention is to suppress the generation of scratching noise caused by water.

  For this reason, in the bellows portion 71 according to the present embodiment, out of the opposing outer peripheral surface Ga facing between the adjacent peak portions 71a to 71f, drainage grooves are formed in each outer peripheral surface Ga arranged on the outer ring side mounting portion 72 side. 74 is provided. The drainage groove 74 is formed so as to be opened outward in the radial direction of the bellows portion 71 in a state where the opposed outer peripheral surfaces Ga are in contact with each other. Thereby, even if the outer peripheral surfaces Ga of the ridges 71a to 71f are in contact with each other in a state where water is interposed in the contraction portion, the water is pushed and moved in various directions by the contact between the outer peripheral surfaces Ga. Then, a certain amount flows into the drain groove 74. That is, the water moved in the circumferential direction of the outer circumferential surface Ga by the contact between the outer circumferential surfaces Ga easily flows into the drainage groove 74 formed orthogonal to the circumferential direction.

  Then, the water flowing into the drain groove 74 flows well in the radial direction of the outer peripheral surface Ga by the centrifugal force generated with the operation of the constant velocity joint 10 and acting on the boot 70, and is quickly discharged to the outside from the opening. Is done. At this time, the groove width of the drainage groove 74 is widened from a to b from the valley bottom Bo side toward the peak portions 71a to 71f. That is, the channel cross-sectional area A of the drainage groove 74 that extends from the valley bottom Bo side to the peak portions 71a to 71f side is enlarged. For this reason, even if a large amount of water flows into the drainage groove 74, the drainage groove 74 does not become a resistance, and the water is discharged well from the drainage groove 74 to the outside. Moreover, the water moved to the radial direction other than the circumferential direction of outer peripheral surface Ga by contact of opposing outer peripheral surfaces Ga is discharged | emitted outside from each peak part 71a-71f side.

  As a result, even if the outer peripheral surfaces Ga of the ridges 71a to 71f having water attached to each other are in contact with each other at the contraction portion, water is discharged well between the opposing outer peripheral surfaces Ga, and water is interposed between the outer peripheral surfaces Ga. Since the contact is made in a state where no contact is made, it is possible to satisfactorily suppress the generation of a large rubbing sound caused by water.

  As is clear from the above description, according to the above embodiment, when water (fluid) is attached to the outer peripheral surface Ga surface, for example, when the constant velocity joint 10 rotates in a bent state, the bellows portion In the portion where 71 is contracted, the opposed outer peripheral surface Ga in contact pushes and moves the water adhering to the surface of the outer peripheral surface Ga and flows into the drain groove 74. The water flowing into the drainage groove 74 flows through the drainage groove 74 by the centrifugal force generated with the rotation of the bellows part 71 and is discharged to the outside of the bellows part 71. For this reason, the friction coefficient between the outer peripheral surfaces Ga which contact is uniform, and generation | occurrence | production of the abrasion sound resulting from a stick slip is suppressed.

  Moreover, according to the said embodiment, the drainage groove 74 is centering on the centerline of the boot 70 in the radial direction of each outer peripheral surface Ga which is a direction which goes to each peak part 71a-71f side from the valley bottom Bo side of each outer peripheral surface Ga. Are formed radially. For this reason, when the opposed outer peripheral surface Ga that is in contact with the contracted portion of the bellows portion 71 pushes out the water adhering to the outer peripheral surface Ga surface, the extruded water moves in the circumferential direction of the opposing outer peripheral surface Ga, thereby forming a radial direction. The water efficiently flows into the drainage groove 74 and is quickly discharged from the opening of the drainage groove 74 to the outside.

  Moreover, according to the said embodiment, the groove width of the drainage groove 74 (groove) is expanded so that the flow-path cross-sectional area A may be expanded toward each peak part 71a-71f side from the valley bottom Bo side. Is formed. Thereby, the water that has flowed into the drainage groove 74 can flow out to the outside without resistance, and the water between the opposing outer peripheral surfaces Ga is discharged well.

  Moreover, according to the said embodiment, the drainage groove 74 (groove) is the outer peripheral surface by the side of the outer ring | wheel side attaching part 72 which is one outer peripheral surface Ga among the opposing outer peripheral surfaces Ga which each adjacent peak part 71a-71f faces. It is provided only in Ga. Thereby, it is not necessary to provide the drain groove 74 in both opposing outer peripheral surfaces Ga, and it can form at low cost.

  Moreover, according to the said embodiment, the drain groove 74 is one outer peripheral surface Ga where the distance from the valley bottom Bo to the peak parts 71a-71f is short among each opposing outer peripheral surface Ga of each adjacent peak part 71a-71f. Provided. Thereby, the water that has flowed into the drainage groove 74 flows through the short drainage groove 74 by the centrifugal force generated with the rotation of the bellows part 71 and is discharged from the opening to the outside of the bellows part 71 in a short time.

(About modification)
In the above embodiment, the drain grooves 74 are formed radially on the outer peripheral surface Ga with the center line of the boot 70 as the center. However, the present invention is not limited to this mode, and the drainage groove may be a drainage groove 75 shown in FIG. The drainage groove 75 is formed so that the center line has a predetermined angle α ° with respect to an imaginary line drawn radially around the center line of the boot 70.

  At this time, the predetermined angle α ° means that the water in the drainage groove 75 is quickly discharged to the outside by the urging force of the centrifugal force generated by the boot 70 rotating with the operation of the bent constant velocity joint 10. It is preferable that the angle enables the above. In addition, what is necessary is just to let the rotation direction of the boot 70 rotated with the action | operation of the constant velocity joint 10 mentioned above be the rotation direction at the time of advance of a vehicle with high use frequency. The direction of the arrow shown in FIG. 6 shows the rotational direction of the boot 70 when the vehicle moves forward as an example. Further, the drainage groove 74 and the drainage groove 75 differ only in the arrangement angle of the drainage groove, and are otherwise the same.

  In addition, in the said embodiment and deformation | transformation aspect, the drainage grooves 74 and 75 (groove) were provided in the outer peripheral surface Ga by the side of the outer ring | wheel side attaching part 72 among the opposing outer peripheral surfaces Ga which each adjacent peak part 71a-71f faces. However, the present invention is not limited thereto, and the drain grooves 74 and 75 may be provided on the outer peripheral surface Ga on the shaft side mounting portion 73 side of the outer peripheral surface Ga facing each of the adjacent peak portions 71a to 71f. Moreover, you may provide the drain grooves 74 and 75 in the both sides of the opposing outer peripheral surface Ga which face each other. However, when the drain grooves 74 and 75 are provided on both sides of the opposing outer peripheral surface Ga facing each other, it is preferable that the drain grooves 74 and 75 are not in contact with each other when the opposing outer peripheral surfaces Ga are in contact with each other in the contracted portion. . The corresponding effects can be obtained also by these.

  Moreover, in the said embodiment and modification, in order to increase the flow-path cross-sectional area of the drain grooves 74 and 75, the groove width of the drain grooves 74 and 75 was expanded from a to b. However, the present invention is not limited to this mode, and the channel cross-sectional area may be increased by increasing the groove depth from the valley bottom Bo side toward the peak portions 71a to 71f without changing the groove width. Furthermore, both the groove width and the groove depth may be enlarged to increase the channel cross-sectional area.

  Moreover, in the said embodiment and deformation | transformation aspect, although the several drainage grooves 74 and 75 were provided, the drainage grooves 74 and 75 may be only one. This also provides a reasonable effect. The fluid applicable to the present invention is not limited to water. Any fluid can be applied as long as it is a fluid that may cause the friction coefficient between the opposing outer peripheral surfaces Ga to be non-uniform when the opposing outer peripheral surfaces Ga contact each other in the contracted portion.

  Further, in the above embodiment, the boot 70 according to the invention has been described as being applied to a fixed ball type constant velocity joint. However, the present invention is not limited to this, and the boot 70 can also be applied to a sliding ball type constant velocity joint. It can also be applied to various tripod type constant velocity joints. Even in such a configuration, the same effect can be obtained.

  1: constant velocity joint assembly, 10: constant velocity joint, 20: outer ring, 60: shaft, 70: boot (boot for constant velocity joint), 71: bellows portion, 72: outer ring side mounting portion, 73: shaft side mounting Part, 74, 75: drainage groove (groove), Ga: outer peripheral surface.

Claims (6)

A constant velocity joint boot having a bellows portion formed alternately and continuously between a mountain portion and a valley portion,
A boot for a constant velocity joint, wherein a groove for discharging a fluid from the valley bottom side toward the peak portion side is provided on an outer peripheral surface connecting the apex of the peak portion and the valley bottom of the valley portion. In the state where the opposing outer peripheral surfaces connecting the apex of the adjacent peak portions and the valley bottom of the valley portion located between the peak portions are in contact with each other,
The groove is formed to open radially outward.
The constant velocity joint boot according to claim 1. The constant velocity joint boot is provided with a plurality of the grooves,
3. The constant velocity joint boot according to claim 1, wherein the plurality of grooves are formed radially outward from a center line of the constant velocity joint boot.   The constant velocity joint boot according to any one of claims 1 to 3, wherein the groove is formed so that a cross-sectional area of a flow path is enlarged from the valley bottom side toward the peak portion side. The groove is provided on one outer peripheral surface of the opposing outer peripheral surface that connects the apex of the adjacent peak portions and the valley bottom located between the peak portions,
The other outer peripheral surface of the opposed outer peripheral surface is formed in a non-recessed shape,
The boot for constant velocity joints as described in any one of Claims 1-4. The distance from the valley bottom to the peak on one of the opposing outer peripheral surfaces is shorter than the distance from the valley bottom to the peak on the other of the opposing outer peripheral surfaces,
The groove is provided on one of the opposed outer peripheral surfaces.
The constant velocity joint boot according to claim 5.

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