WO2017047377A1

WO2017047377A1 - Boot band

Info

Publication number: WO2017047377A1
Application number: PCT/JP2016/075363
Authority: WO
Inventors: 慎吾吉永; 石島　実
Original assignee: Ntn株式会社
Priority date: 2015-09-18
Filing date: 2016-08-30
Publication date: 2017-03-23

Abstract

A boot band 31 is provided with: a band body 35 obtained by forming a band plate-like member 32 in a ring shape by joining in an overlapping manner the inner peripheral surfaces of the opposite ends 33, 34 of the band plate-like member 32; and a lever 38 attached to the joint 36 of the band body 35 and obtained by forming a strip-like member 37 in a circular arc shape. When the lever 38 is folded back at an end of the lever 38 and overlapped on the band body 35, the band body 35 is reduced in diameter and tightened around a boot for a constant velocity universal joint, the boot being disposed inside the band body 35, the end of the lever 38 serving as the fulcrum at which the lever 38 is folded back. Two-stage chamfered sections 42, 43 arranged in the direction of the lever plate thickness are provided at the fulcrum-side portion 41 of the end of the lever 38.

Description

Boots band

The present invention is a boot band which is attached to a fixed type and a sliding type constant velocity universal joint incorporated in automobiles and various industrial machines, and which tightens a boot for preventing foreign matter intrusion from outside the joint and leakage of lubricant from inside the joint. About.

For example, there are two types of constant velocity universal joints that are used as means for transmitting rotational force from an automobile engine to wheels at a constant speed: a fixed constant velocity universal joint and a sliding constant velocity universal joint. Both of these constant velocity universal joints have a structure in which two shafts on the driving side and the driven side are connected so that rotational torque can be transmitted at a constant speed even if the two shafts have an operating angle.

A drive shaft that transmits power from an automobile engine to a drive wheel needs to cope with angular displacement and axial displacement caused by a change in the relative positional relationship between the engine and the wheel. Therefore, the drive shaft is generally equipped with a sliding constant velocity universal joint on the engine side (inboard side) and a fixed constant velocity universal joint on the drive wheel side (outboard side). It has a structure in which fast universal joints are connected by a shaft.

In these sliding type constant velocity universal joints or fixed type constant velocity universal joints, the outer joint member of the constant velocity universal joint is used to prevent leakage of the lubricant enclosed inside the joint and to prevent foreign matter from entering from the outside of the joint. Boots are mounted between the shaft. This type of boot has a sealing property secured by tightening with a metal boot band (for example, see Patent Document 1) and fixing it to the outer joint member and the shaft.

The boot band disclosed in Patent Document 1 is called a one-touch type, and is attached to a band body formed into a ring shape by joining both end portions of a band plate-like member, and a joint portion of the band body. And a lever obtained by forming a strip-like member into an arc shape.

The assembly of this boot band is as follows. First, prior to assembling the boot band, the end of the boot is attached to the outer joint member or shaft of the constant velocity universal joint. At this time, a boot band is disposed outside the end of the boot.

In this state, in the boot band, the base end of the lever is folded back as a fulcrum, and the band main body is reduced in diameter by overlapping the lever on the band main body. The end of the boot is fastened and fixed to the outer joint member or shaft of the constant velocity universal joint by the boot band whose diameter is reduced.

JP-A-10-26108

By the way, in general, in a one-touch type boot band, when the base end portion of the lever is folded back as a fulcrum, the contact portion of the band main body is bent along the base end portion of the lever. At this time, if an edge is formed at the fulcrum side part of the base end portion of the lever, the radius of curvature at the abutting portion of the band body that abuts against the edge is reduced, so that stress concentration is concentrated on the abutting portion of the band body. Occurs locally.

When this local stress concentration occurs, when the boot band is reused in the evaluation test of the constant velocity universal joint, if the lever is repeatedly folded, the fulcrum side of the base end portion of the lever is caused by metal fatigue. There is a risk of the band body breaking near the site.

In order to relieve the local stress concentration as described above and prevent the band body from being broken due to repeated folding of the lever, the boot band disclosed in Patent Document 1 has a fulcrum side portion at the base end portion of the lever. The edge is removed, and the fulcrum side portion is formed in a curved surface shape.

However, in the boot band disclosed in Patent Document 1, an edge process such as barrel processing or shot blasting is performed in order to remove the edge at the fulcrum side portion of the base end portion of the lever and make the fulcrum side portion into a curved surface shape. Necessary. As a result, the boot band is expensive.

Therefore, the present invention has been proposed in view of the above-mentioned problems, and the object of the present invention is to relieve local stress concentration, reduce metal fatigue due to repeated lever folding, and break the band body. An object of the present invention is to provide a boot band capable of preventing costs and reducing costs by simple means.

As technical means for achieving the above-mentioned object, the present invention provides a band body in which a band plate member is formed into a ring shape by joining the inner peripheral surfaces of both end portions of the band plate member so as to overlap each other. And a lever attached to the joint of the band main body, and a strip-shaped member formed into an arc shape. The band main body is reduced in diameter by folding the lever end on the fulcrum and overlapping the lever on the band main body. A boot band for fastening a constant velocity universal joint boot arranged inside the band body, wherein a plurality of chamfered portions along the lever plate thickness direction are provided at a fulcrum side portion of the end portion of the lever. And

In the boot band of the present invention, by providing a plurality of chamfered portions along the lever plate thickness direction at the fulcrum side portion of the end of the lever, when the end of the lever is folded back as a fulcrum, the end of the lever The band body is bent along the plurality of chamfered portions formed. By increasing the radius of curvature of the band main body in contact with the chamfered portion, local stress concentration generated in the contact portion of the band main body can be reduced.

As a result, even if the lever is repeatedly folded back, the strength of the band body can be ensured, and the band body can be prevented from breaking near the fulcrum side portion of the end of the lever. Further, since the plurality of chamfered portions can be formed by simple means, the cost of the boot band can be reduced as compared with barrel processing or the like.

In the present invention, the multi-step chamfered portion is a two-step chamfered portion in which the chamfer angle of the second step is larger than the chamfer angle of the first step from the end of the lever with respect to the normal direction of the band body. The chamfer angle of the second step is larger than the normal direction of the band body than the chamfer angle of the first step from the end of the band, and the chamfer angle of the third step is larger than the chamfer angle of the second step. It is desirable to have a three-stage chamfered portion that is larger than the normal direction.

If such a configuration is adopted, the local stress concentration generated at the contact portion of the band main body can be surely alleviated, and the breaking strength of the band main body can be secured. As a result, it is possible to reliably prevent the band body from being broken near the fulcrum side portion of the end of the lever. Further, in the case of a two-step or three-step chamfered portion, the processing can be simplified, and the cost can be greatly reduced as compared with barrel processing.

In the present invention, the two-step chamfered portion has a first-step chamfering angle of 10 to 45 ° with respect to the normal direction of the band body, and a second-step chamfering angle of 45 to the normal direction of the band body. A configuration in which the angle is 80 ° is desirable. Further, in the third step chamfered portion, the first step chamfer angle is 10 to 45 ° with respect to the normal direction of the band body, and the second step chamfer angle is 30 to 60 with respect to the normal direction of the band body. It is desirable that the third stage chamfer angle is 50 to 80 ° with respect to the normal direction of the band body.

If such a configuration is adopted, the chamfered portion of two or three steps can be set at an optimum angle, and it becomes easy to ensure the breaking strength of the band body. As a result, even if the lever is repeatedly folded, it is possible to more reliably prevent the band body from breaking near the fulcrum side portion of the end of the lever.

According to the present invention, it is possible to alleviate local stress concentration generated at the contact portion of the band body when the lever is folded back. By relaxing the local stress concentration, it is possible to ensure the breaking strength of the band body even when the lever is repeatedly folded, and to prevent the band body from breaking near the fulcrum side part at the end of the lever. In the evaluation test of the constant velocity universal joint, the band can be reused. In addition, since a plurality of chamfered portions can be formed by simple means, the cost of the boot band can be reduced compared to barrel processing or the like. As a result, it is possible to provide a boot band that is highly reliable, has a long life, and is inexpensive.

In embodiment of this invention, it is a front view which shows the state before turning back the lever of a boot band. It is a front view which shows the state after folding the lever of a boot band. FIG. 3 is a perspective view showing a fulcrum side portion of the end portion of the lever in the embodiment product 1 of the present invention. It is principal part expanded sectional drawing which shows the state which turned back the lever of the boot band in the implementation goods 1 of this invention. FIG. 6 is a perspective view showing a fulcrum side portion of the end of the lever in the embodiment product 2 of the present invention. FIG. 6 is an enlarged cross-sectional view of a main part showing a state in which the lever of the boot band is folded back in the embodiment product 2 of the present invention. It is a comparison product for comparing with the implementation product of the present invention, and is a perspective view showing a fulcrum side portion of the end of the lever. It is a comparison product for comparing with the implementation product of the present invention, and is a principal part enlarged sectional view showing a state where the lever of the boot band is folded back. It is a graph which shows the frequency | count of folding | turning of a lever until the band main body fractures | ruptures about the

implementation products

1 and 2 of this invention, and a comparison product. It is a front view which shows the state which clamp | tightened and fixed the edge part of the boot to the outer joint member and shaft of the constant velocity universal joint with the boot band. It is sectional drawing of FIG.

Embodiments of a boot band according to the present invention will be described in detail below with reference to the drawings.

As a constant velocity universal joint to which the boot band in the following embodiments is applied, it is incorporated in a drive shaft of an automobile and connects two shafts of a drive side and a driven side, and the two shafts take a working angle and rotate at a constant speed. An undercut-free type constant velocity universal joint which is one of fixed type constant velocity universal joints having a structure for transmitting

The present invention can also be applied to other fixed type constant velocity universal joints such as a Rzeppa type constant velocity universal joint, a double offset type constant velocity universal joint, a cross groove type constant velocity universal joint, a tripod type, and the like. The present invention can also be applied to a sliding type constant velocity universal joint such as a speed universal joint.

FIG. 7 shows an undercut-free constant velocity universal joint constituting a part of the drive shaft, a shaft, and a boot mounted between the constant velocity universal joint and the shaft. FIG. 8 is a cross-sectional view of FIG.

As shown in FIGS. 7 and 8, the constant velocity universal joint includes an outer joint member 11, an inner joint member 12, a ball 13, and a cage 14.

In the outer joint member 11, arc-shaped track grooves 15 extending in the axial direction are formed at a plurality of locations on the spherical inner peripheral surface 16 at equal intervals in the circumferential direction. The inner joint member 12 is paired with the track groove 15 of the outer joint member 11, and arc-shaped track grooves 17 are formed at a plurality of locations on the spherical outer peripheral surface 18 at equal intervals in the circumferential direction. The ball 13 is interposed between the track groove 15 of the outer joint member 11 and the track groove 17 of the inner joint member 12. The cage 14 is disposed between the spherical inner peripheral surface 16 of the outer joint member 11 and the spherical outer peripheral surface 18 of the inner joint member 12 to hold the ball 13.

The opening side portion of the track groove 15 of the outer joint member 11 and the back side portion of the track groove 17 of the inner joint member 12 are formed in a straight shape parallel to the joint axial direction to increase the operating angle. One end of a shaft 19 is connected to the inner joint member 12 by spline fitting. An inner joint member of a sliding type constant velocity universal joint (not shown) is connected to the other end of the shaft 19 by spline fitting.

This constant velocity universal joint has a bellows shape made of rubber or resin between the outer joint member 11 and the shaft 19 in order to prevent leakage of the lubricant sealed inside the joint and prevent foreign matter from entering from the outside of the joint. The boot 20 is provided with a structure. By encapsulating a lubricant in the inner space of the outer joint member 11 and the boot 20, lubricity is ensured during the operation in which the shaft 19 rotates with an operating angle with respect to the outer joint member 11.

The boot 20 includes a large-diameter end portion 21 fastened and fixed to the outer peripheral surface of the outer joint member 11 by a boot band 31, a small-diameter end portion 22 fastened and fixed to the outer peripheral surface of the shaft 19 by the boot band 31, and a large-diameter end The portion 21 and the small-diameter end portion 22 are connected to each other, and an elastic bellows portion 23 having a diameter reduced from the large-diameter end portion 21 toward the small-diameter end portion 22 is formed. The large-diameter end 21 and the small-diameter end 22 of the boot 20 are fastened and fixed by the boot band 31 so as to ensure sealing performance.

Since the constant velocity universal joint has a function of rotating while taking an operating angle, the boot 20 is made of rubber or resin having a telescopic bellows shape to ensure flexibility to follow its behavior. Is used. As the rubber material, chloroprene rubber or silicon rubber having a surface hardness of Hs 45 to 75 is suitable. As the resin material, a thermoplastic polyester elastomer having a surface hardness of HD 38 to 55 or a composition containing a thermoplastic polyester elastomer is suitable.

The metal boot band 31 that fastens and fixes the above-described boot 20 to the outer joint member 11 and the shaft 19 has the following structure. FIG. 1 shows a state before the boot 20 (see FIG. 7) is fastened and fixed, and FIG. 2 shows a state after the boot 20 (see FIG. 7) is fastened and fixed.

The boot band 31 of this embodiment is called a one-touch type. As shown in FIG. 1, a band formed into a ring shape by joining both

end portions

33 and 34 of a metal band plate member 32. A main part is composed of a main body 35 and a lever 38 which is attached to a joint portion 36 of the band main body 35 and is formed by forming a metal strip member 37 into an arc shape. The band main body 35 is provided with a stopper 39 for fixing the lever 38 after being folded back.

The band body 35 has a joint portion 36 formed by abutting the inner peripheral surface of the one end portion 33 of the band plate member 32 and the inner peripheral surface of the other end portion 34 and fixing them by welding or the like. The lever 38 is attached to the band main body 35 by fixing its base end portion to the outer peripheral surface of the joint portion 36 of the band main body 35 by welding or the like. The stopper portion 39 is composed of a pair of tongue pieces 40 provided so as to stand up radially outward on both sides in the width direction of the band main body 35. Since the lever 38 requires a folding operation, the lever 38 is thicker than the band main body 35 in order to ensure its strength.

The assembly of the boot band 31 having the above configuration is performed in the following manner. Prior to the assembly of the boot band 31, the large-diameter end portion 21 of the boot 20 is fitted on the outer peripheral surface of the outer joint member 11 of the constant velocity universal joint, and the small-diameter end portion 22 of the boot 20 is mounted on the outer peripheral surface of the shaft 19. Fit outside. At this time, the boot band 31 is disposed outside the large-diameter end 21 and the small-diameter end 22 of the boot 20.

In this state, the lever 38 is folded back with the base end portion of the lever 38 of the boot band 31 as a fulcrum, so that the concave curved inner peripheral surface of the lever 38 is superimposed on the convex curved outer peripheral surface of the band main body 35. The band main body 35 is reduced in diameter by overlapping the lever 38 on the band main body 35. The boot 20 is tightened and fixed to the outer peripheral surface of the outer joint member 11 and the outer peripheral surface of the shaft 19 by the boot band 31 whose band main body 35 has a reduced diameter.

The distal end of the lever 38 is pressed by the tongue piece 40 and fixed to the band body 35 by crimping the tongue piece 40 of the stopper 39 of the band body 35 inwardly.

In the boot band 31 of the embodiment shown in FIG. 3A, a plurality of, for example, two-step chamfered

portions

42 and 43 along the lever plate thickness direction are provided in the fulcrum side portion 41 of the base end portion of the lever 38. In this embodiment, the number of steps of the chamfered

portions

42 and 43 is two, but can be three or more. In the boot band 31 of the embodiment shown in FIG. 4A, three steps of chamfered portions 44 to 46 along the lever plate thickness direction are provided in the fulcrum side portion 41 of the base end portion of the lever 38. The chamfered portion may have four or more steps, and the number of steps is arbitrary.

Thus, by providing the two-step chamfered

portions

42 and 43 or the three-step chamfered portions 44 to 46 at the fulcrum side portion 41 of the base end portion of the lever 38, the base end portion of the lever 38 is folded back as a fulcrum. At this time, as shown in FIG. 3B or 4B, the band main body 35 is bent along the two-step chamfered

portions

42 and 43 or the three-step chamfered portions 44 to 46 formed at the base end portion of the lever 38. become.

By increasing the radius of curvature at the contact portion of the band main body 35 contacting the chamfered

portions

42, 43 or the chamfered portions 44-46, the two-step chamfered

portions

42, 43 or the three-step chamfered portions 44-46 are used. The local stress concentration generated at the contact portion of the band main body 35 can be alleviated.

As a result, when the boot band 31 is reused in the evaluation test of the constant velocity universal joint, the breaking strength of the band main body 35 can be secured even if the lever 38 is repeatedly folded, and the base end of the lever 38 can be secured. It is possible to prevent the band main body 35 from being broken near the fulcrum side portion 41 of the portion. Further, the two-step chamfered

portions

42 and 43 or the three-step chamfered portions 44 to 46 can be formed at a low cost by a simple means such as cutting or pressing.

As shown in FIG. 3A, the two-step chamfered

portions

42 and 43 have a second-step chamfering angle β with respect to the normal direction of the band main body 35 rather than the first-step chamfering angle α from the end of the lever 38. It is getting bigger. That is, the first-stage chamfering angle α is 10 to 45 °, preferably 20 to 40 ° with respect to the normal direction of the band body 35, and the second-stage chamfering angle β is set to the normal direction of the band body 35. The angle is 45 to 80 °, preferably 50 to 70 °.

In this embodiment, the first-stage chamfering angle α is 30 ° with respect to the normal direction of the band main body 35, and the second-stage chamfering angle β is 60 ° with respect to the normal direction of the band main body 35.

As shown in FIG. 4A, the three-stage chamfered portions 44 to 46 have a second-stage chamfering angle β from the end of the lever 38 with respect to the normal direction of the band body 35 rather than the first-stage chamfered angle α. The third chamfer angle γ is larger than the second chamfer angle β with respect to the normal direction of the band main body 35. That is, the first step chamfering angle α is 10 to 45 °, preferably 20 to 30 ° with respect to the normal direction of the band main body 35, and the second step chamfering angle β is set to the normal direction of the band main body 35. The chamfering angle γ at the third step is 50 to 80 °, preferably 65 to 75 ° with respect to the normal direction of the band main body 35, with respect to 30 to 60 °, preferably 40 to 50 °.

In this embodiment, the first step chamfering angle α is 30 ° with respect to the normal direction of the band main body 35, and the second step chamfering angle β is 50 ° with respect to the normal direction of the band main body 35. The chamfer angle γ of the step is set to 70 ° with respect to the normal direction of the band main body 35.

By setting the two-step chamfering angles α, β or the three-step chamfering angles α, β, γ within the above-mentioned range, the two-

step chamfering portions

42, 43 or the three-step chamfering portions 44 to 46 are optimal angles. It becomes easy to secure the breaking strength of the band main body 35. As a result, the band main body 35 can be more reliably prevented from breaking in the vicinity of the fulcrum side portion 41 of the base end portion of the lever 38, so that the band can be reused in the evaluation test of the constant velocity universal joint. It becomes.

If the two-step chamfering angles α, β or the three-step chamfering angles α, β, γ deviate from the above range, it is difficult to ensure the breaking strength of the band main body 35.

In the case of the two-stage chamfered

portions

42 and 43, if the first-stage chamfer angle α is smaller than the lower limit value (10 °) or the second-stage chamfer angle β is larger than the upper limit value (80 °), the chamfering effect is obtained. It becomes difficult to exhibit the chamfering and mold the chamfer. Further, if the upper and lower limit boundary values (45 °) between the first-stage chamfer angle α and the second-stage chamfer angle β are shifted, it is difficult to obtain a uniform dispersion effect at the two-

stage chamfers

42 and 43. It becomes.

In the case of the three-stage chamfered portions 44 to 46, if the first-stage chamfer angle α is smaller than the lower limit value (10 °) or the third-stage chamfer angle γ is larger than the upper limit value (80 °), the chamfering effect is obtained. It becomes difficult to exhibit the chamfering and mold the chamfer. Also, the upper and lower boundary values (45 °, 30 °) between the first step chamfer angle α and the second step chamfer angle β, and the second step chamfer angle β and the third step chamfer angle γ If the lower limit boundary values (60 °, 50 °) are deviated, it is difficult to obtain a uniform dispersion effect in the three-stage chamfered portions 44 to 46.

As shown in FIGS. 3A and 3B, the applicant of the present invention has a boot band 31 (implemented product 1 of the present invention) in which two steps of

chamfered portions

42 and 43 are provided at a fulcrum side portion 41 at the base end of the lever 38. 4A and 4B, a boot band 31 (a product 2 according to the present invention) in which three steps of chamfered portions 44 to 46 are provided in the fulcrum side portion 41 of the base end portion of the lever 38, and FIG. As shown in FIG. 5B, a test was performed to compare with a boot band 131 (comparative product) in which an edge portion 144 is provided without chamfering at a fulcrum side portion 141 of the base end portion of the lever 138.

In the test, the band

main bodies

35 and 135 were broken in the vicinity of the

fulcrum side portions

41 and 141 of the base end portions of the

levers

38 and 138 by folding the

levers

38 and 138 for the

products

1 and 2 and the comparative products. The number of iterations was verified. In addition, this verification test was done about four

implementation products

1 and 2 and four comparison products.

As a result, as shown in FIG. 6, in the four comparative products, the number of repetitions until the band main body 135 broke was 3 to 4 times. On the other hand, in the four working

products

1 and 2, the number of repetitions until the band body 35 broke was 6 to 7 times.

In the working products 1 and 2 (see FIG. 3B and FIG. 4B), the band that contacts the two-step chamfered

portions

42 and 43 or the three-step chamfered portions 44 to 46 when the base end portion of the lever 38 is folded back as a fulcrum. The radius of curvature at the contact portion of the main body 35 is larger than the radius of curvature at the contact portion of the band main body 135 that contacts the edge portion 144 in the comparative product (see FIG. 4B). Thus, in the

products

1 and 2, local stress concentration generated at the contact portion of the band main body 35 can be reduced.

As described above, the working

products

1 and 2 that can alleviate the local stress concentration generated in the contact portion of the band main body 35 can be folded back twice as much as the comparative product. As a result, it has been clarified that in the

products

1 and 2, the band main body 35 can be prevented from being broken in the vicinity of the fulcrum side portion 41 of the base end portion of the lever 38 when the lever 38 is folded back.

The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the gist of the present invention. The equivalent meanings recited in the claims, and all modifications within the scope.

Claims

A band body formed by forming the band plate-shaped member into a ring shape by joining the inner peripheral surfaces of both end portions of the band plate-shaped member, and a strip-shaped member attached to the joint portion of the band body. A lever formed in a circular arc shape, the band main body is reduced in diameter by folding the lever with the end of the lever as a fulcrum, and overlapping the lever on the band main body. A boot band for tightening a joint boot,
A boot band comprising a plurality of chamfered portions along a lever plate thickness direction at a fulcrum side portion of an end portion of the lever.
The multi-step chamfered portion is a two-step chamfered portion in which the chamfer angle at the second step is larger than the chamfer angle at the first step from the end of the lever with respect to the normal direction of the band body. The boot band as described in.
The two-step chamfered portion has a first-step chamfering angle of 10 to 45 ° with respect to the normal direction of the band body, and a second-step chamfering angle of 45 to 80 ° with respect to the normal direction of the band body. The boot band according to claim 2.
The plurality of chamfered portions have a second chamfer angle larger than the first chamfer angle from the end of the lever with respect to the normal direction of the band body, and the second chamfer angle The boot band according to claim 1, wherein the chamfered portion is a three-stage chamfered portion in which the chamfer angle of the third stage is larger than the normal direction of the band body.
The three-step chamfered portion has a first-step chamfering angle of 10 to 45 ° with respect to the normal direction of the band body, and a second-step chamfering angle of 30 to 60 ° with respect to the normal direction of the band body. The boot band according to claim 4, wherein the chamfer angle at the third stage is 50 to 80 ° with respect to the normal direction of the band body.