JPH09177993A - Boot attaching structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To always fasten a boot fixing part to an opposite member in the best from with a boot band by setting up the dimensions of the band groove width of a boot fixing part and a boot band width, and setting up a convex part width to band width. SOLUTION: The parts of boot attaching structure are designated in such a way as the width of a band groove 4 on the outer periphery of a boot fixing part 1 by W; the width of a convex part 12 on an inner periphery by (b); its height by (f); the depth of the engaging groove 21 of an opposite member 2 where the convex part 12 is fitted by (a); its width by (b); and the height of projections 22 which exist on both sides of the engaging groove 21 and bite in the boot fixing part 1 by (c), and a dimensional relationship among them is set up as follows. [w<W<1.3w], [0.3w<=b<=0.5w], [0.9b<=e<=b], [0.2mm<=c<=0.5mm], [0.5mm<=a<=1.5mm], [f<=(a-c)] and [(b/a)>=3]. In addition, the radius of curvature of an arced face from the middle flat face 21m of the engaging grove 21 of the opposite member 2 to the projection 22 is set up within the dimension range of [0.1mm<=R<=a].

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boot mounting structure to be mounted on a mating member such as a constant velocity universal joint for automobiles.

[0002]

2. Description of the Related Art Boots provided to prevent the leakage of grease enclosed in a constant velocity universal joint and the intrusion of foreign matter into the interior of a constant velocity universal joint are fitted on the outer periphery of the outer ring of the constant velocity universal joint. It has a diameter portion, a small diameter portion fitted on the outer periphery of the shaft of the constant velocity universal joint, and a bellows portion between the large diameter portion and the small diameter portion.
The large diameter part and the small diameter part of this boot are formed as a cylindrical boot fixing part, which is fitted on the outer periphery of a mating member such as the outer ring or shaft of a constant velocity universal joint, and then tightened with a boot band (metal band). Then, it is airtightly fixed to the mating member.

The above boots are roughly classified into rubber boots and resin boots, and in recent years, resin boots tend to be used frequently. In particular, since resin boots have less elasticity than rubber boots, the fitting and fixing state on the mating member is likely to be unstable, and a special devise has been made in the mounting structure with the mating member. As the boot mounting structure, the one shown in FIGS. 5 and 6 is known.

In the mounting structure shown in FIG. 5, after the boot fixing portion 41, which is the large diameter portion or the small diameter portion of the resin boot, is fitted to the outer periphery of the mating member 42 (the outer ring or shaft of the constant velocity universal joint),
The boot fixing portion 41 is tightened with the boot band 43 to be elastically deformed, and the annular convex portion 44 provided on the inner periphery of the boot fixing portion 41 is brought into close contact with the annular engagement groove 45 provided on the outer periphery of the mating member 42 to make the resin. It fixes the boots. Note that FIG. 5 shows a state after tightening with the boot band 43.

In the mounting structure shown in FIG. 6, a plurality of engaging grooves 52 and projections 53 are alternately formed close to each other on the outer circumference of a mating member 51, and the inner circumference of the boot fixing portion 55 is tightened by the tightening force of the boot band 54. The resin boot is fixed by making the projection 53 bite into. In the case of FIG. 6, the state before tightening by the boot band 54 is shown.

[0006]

In the mounting structure shown in FIG. 5, since the engaging groove 45 has a square shape, its machining needs to be performed by turning (parting off), resulting in high machining cost. . Further, in order to secure the retaining strength and the sealing property of the boot fixing portion 41, the convex portion 44 of the boot fixing portion 41 is provided.
Since it is necessary to make the height h of the resin boot relatively large, the method of molding the resin boot is limited, which also causes a high cost. Further, since the resin boot is generally much harder than the rubber boot and is less likely to be elastically deformed, the protrusion 44
If it is high, the fitting work to the mating member 42 becomes difficult, and if the convex portion 44 is lowered to make this fitting work even a little, there is a problem that the sealing property becomes insufficient.

In the mounting structure shown in FIG. 6, a plurality of engaging grooves 5 are provided.
Since 2 and the protrusion 53 are alternately formed close to each other, it is necessary to form them by complicated copying. Therefore, the number of processing steps is large, and the processing cost is high as in the above case. Also, the tightening force of the boot band 54 causes the boot fixing portion 55 to bite into the protrusion 53 of the mating member 51 to ensure good sealing performance. However, in some resin boots, the protrusion 53 does not move to the protrusion 53. In relation to the biteability of
It is expected that there may be some shortage of good sealability.

In order to solve the above problems, the present applicant previously developed and applied for a boot mounting structure as shown in FIGS. 7 (A) and 7 (B) (Japanese Patent Application No. 6-72995). This boot mounting structure will be described. Incidentally, FIG. 7A shows a partial cross section and a partial side surface of the boot fixing portion 1 of the large diameter portion or the small diameter portion of the resin boot, and the outer ring of the constant velocity universal joint or the mating member 2 of the shaft before band fixing. FIG. 7B shows a partial side surface of only the mating member 2.

An annular convex portion 12 is integrally formed on the inner circumference 11 of the boot fixing portion 1, and an annular band groove 4 is formed on the outer circumference thereof. The resin boot having the boot fixing portion 1 is TP
It is formed from a resin material such as E (thermoplastic elastomer) by injection molding, blow molding, or the like. After the boot fixing portion 1 is fitted into the outer periphery 23 of the mating member 2, the boot band 3 is fitted into the band groove 4. The boot band 3 is a metal binding band.

An annular engaging groove 2 is formed on the outer periphery 23 of the mating member 2.
1, and annular protrusions 22 are integrally formed on both sides of the engagement groove 21. The engaging groove 21 is a circular arc groove having a radius of curvature R ′,
The groove shoulders on both sides thereof are the protrusions 22. The width b and the depth a of the engagement groove 21 shown in FIG. 7B are set so that the convex portion 12 of the boot fixing portion 1 fits properly here, and the protruding portion 22.
Protrudes from the outer periphery 23 of the mating member 2 at a predetermined height c.

The boot fixing part 1 is fitted into the outer periphery 23 of the mating member 2, the convex part 12 is fitted into the engaging groove 21, and both are positioned, and the boot band 3 fitted in the band groove 4 is positioned.
When the boot fixing part 1 is contracted to the mating member 2 by reducing the diameter of the boot fixing part 1, elastic deformation occurs on the inner circumference 11 side of the boot fixing part 1.
The protrusion 12 is displaced toward the engagement groove 21 side, and the protrusion 22 bites into the inner circumference 11 side of the boot fixing portion 1. Due to the fitting of the convex portion 12 and the engaging groove 21 and the strong engagement of the protruding portion 22, the boot fixing portion 1 is fixed to the mating member 2 with high retaining strength and sealing property.

In the boot mounting structure of the above-mentioned prior application,
The following dimensions were set. Width b of the engaging groove 21 of the mating member 2
And the depth a and the height c of the protrusion 22 are set as follows: a = 0.5 to 1.5 mm, b = 3.0 to 5.0 mm, c = 0.1 to 0.5 mm, and (b / a) ≧ Set to 3.

Width b of the engaging groove 21 in the above dimension setting
Is set on the premise that the width w of the boot band 3 is normally 8 to 12 mm, and the protrusion 22 stably bites into the boot fixing portion 1 by setting the width b. Further, the depth a of the engagement groove 21 is determined when the convex portion 12 is securely fitted into the engagement groove 21 and the boot fixing portion 1 receives a combined force in the axial X direction or the radial Y direction. However, the depth is such that a fixing force that does not cause displacement with respect to the mating member 2 is obtained. Further, the height c of the protruding portion 22 is such that the protruding portion 22 surely bites into the boot fixing portion 1, and the inner circumference 11 of the boot fixing portion 1 closely adheres to the outer circumference 23 of the mating member 2 with high airtightness. It is a value. In this case, the upper limit of the width of the protrusion 22 is about 1 mm.

Further, the setting of (b / a) ≧ 3 is to make the engaging groove 21 a shape that can be profiled. With this setting, the processing cost of the engagement groove 21 can be reduced. In addition, (b /
If a) <3, it is difficult to process the engagement groove 21 by a normal copying process, and it is necessary to rely on a turning process (cutting off process), resulting in a high processing cost.

Further, when the above-mentioned dimensions are set, even if the height f of the convex portion 12 of the boot fixing portion 1 is reduced, a strong engagement adhesion force with the engagement groove 21 is obtained, and the boot fixing portion 1 High retention strength and sealability can be secured. Furthermore, by reducing the height f of the convex portion 12, more various methods such as a direct blow method and a press blow method can be applied to the method for molding the resin boot, and the molding cost can be reduced. By reducing the height h, the workability of fitting the mating member 2 is improved.

In the above-mentioned prior application, it has been found that the problems associated with the boot mounting structure shown in FIGS. 5 and 6 can be solved.
However, the dimensional relationship of the protrusion 12 with respect to the width w of the boot band 3, the engaging groove 21 and the protrusion 22 for the protrusion 12,
By further pursuing the dimensional relationship of, it has been found that it can be improved and a more effective type of constant velocity universal joint boot can be provided.

There are various types of constant velocity universal joints such as fixed type, sliding type and cross groove type, and various types of boot materials are used, from resin to rubber such as chloroprene. The structure shown in FIG. 7 may not always be suitable for the boot mounting structure of these various types of constant velocity universal joints. For example, when the structure of FIG. 7 is used for the boot mounting structure that uses the resin boot in the fixed type constant velocity universal joint that can be used up to a high turning angle for the front wheel outboard of an automobile, a slight problem occurs in the sealing property. I have something to do.

That is, in the above resin boot, an additive may be contained in the resin for the purpose of improving the boot moldability, improving the wear resistance of the boot, suppressing the scratching noise of the boot surface, and the like. Depending on the type and amount of this additive, the frictional resistance on the boot surface decreases compared to when it is not added, and it becomes disadvantageous in the sealing part with the mating member of the boot fixing part, which makes the sealing property of FIG. 7 unstable. May be. For example,
As an additive that is effective in suppressing scratching noise, any substance that is generally known as a substance that exerts a lubricating action may be used, although it has a large or small effect, for example, paraffin wax, crostarin wax, polyethylene wax, montan wax. , Silicone oil, fatty acid, fatty acid amide, ester wax, fatty alcohol, alcohol ester, fatty acid ester, polyether compound, mineral oil, synthetic oil, vegetable oil, etc. widely used for rubber and resin, and other applications Examples include those used for lubricating oils and the like. Further, these additives may be used by being added to the boot material or in a state of being adhered (applied) to the outer surface of the boot. However, this kind, usage and dose must be within a range that is satisfactory in terms of moldability and product performance, as well as surface modification of the base material boot material. From this point, in the resin boots for constant velocity universal joints, the use of which is increasing recently, the compound RO (R′O) _n OH {R is an alkyl group and R ′ is a compound disclosed in JP-A-3-139557. An alkylene group having 1 to 6 carbon atoms, n is 1 to
Indicates an integer of 100. } Is considered to be particularly effective. However, such an additive having a high effect of suppressing rubbing noise causes a reduction in frictional resistance, and as a disadvantage thereof, the current sealing force may be insufficient.

Therefore, the object of the present invention is to pursue the dimensional relationship of the above-mentioned prior application more effectively, and to be effective for mounting boots of constant velocity universal joints of various types, and to obtain higher mounting strength and sealability. The present invention is to provide a boot mounting structure.

[0020]

SUMMARY OF THE INVENTION According to the present invention, by tightening a boot band fitted in a band groove on the outer circumference of a boot fixing portion, a convex portion on the inner circumference of the boot fixing portion is pressed against an engaging groove of a mating member. Then, in the boot mounting structure of FIG. 7 in which the protrusions on both sides of the engaging groove are bited into the boot fixing portion to fix the boot fixing portion to the outer periphery of the mating member, in the width direction center of the band groove and the convex portion of the boot fixing portion. The center lines are set so as to face each other, and the width W of the band groove, the width w of the boot band, the width e of the convex portion, and the width b of the engaging groove of the mating member are [w <W ≦ 1.3w]. , [
0.3w ≦ b ≦ 0.5w], [0.9b ≦ e ≦ b], and the height f of the convex portion from the inner circumference of the boot fixing portion, the depth a of the engaging groove of the mating member, Between the heights c of the protrusions on both sides of the engaging groove from the outer circumference of the mating member, [0.2 mm ≦ c ≦
0.5mm], [0.5mm ≤ a ≤ 1.5] mm, and further, [f ≤ (ac)], [(b / a) ≥ 3] The above object is achieved.

Although the sectional shape of the engaging groove of the mating member in the axial direction of the mating member is not specified, the central portion of the mating groove may be parallel to the axis depending on the type and material of the boot fixing portion and the mating member. The flat surface has a shape in which an arcuate surface is continuous from the flat surface toward the protrusion apexes on both sides of the engaging groove, and the radius of curvature R of the arcuate surface on at least one side of the flat surface is [0.1 mm ≦ R ≦
In some cases, it may be desirable to set the dimension a].

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention applied to the boot mounting structure shown in FIG. 7 will be described below with reference to FIGS. It should be noted that the same or corresponding portions as those in FIG. 7 of FIGS. 1 to 4 are designated by the same reference numerals to avoid duplication of description.

FIG. 1A shows a state before the boot fixing portion 1 is fitted to the mating member 2 and tightened by the boot band 3, and FIG. 1B shows after the tightening by the boot band 3. The state of is shown. The schematic structure of this boot attachment structure is the same as that of FIG. 7, except that the following finer dimension setting is performed. That is, according to the present invention, the dimensional relationship between the width w of the boot band 3 and the width W of the band groove 4, the width e and the height f of the convex portion 12 with respect to the boot band 3, and the respective dimensions a to c of the mating member 2. As a result of conducting an experimental investigation under various conditions and also an experimental investigation of the cross-sectional shape of the engagement groove 21 of the mating member 2 in the axial direction under various conditions, the following dimensions were set.

As shown in FIG. 2, in the boot fixing portion 1, the center line of the band groove 4 at the center in the width direction and the inner circumference 11 thereof.
After setting the center lines of the protrusions at the center in the width direction to substantially coincide with each other, the width W of the band groove 4, the width w of the boot band 3, the width e of the protrusion 12, the engaging groove of the mating member 2 are set. 21 between the widths b, [w <W ≦ 1.3w], [0.9b ≦ e ≦ b], [
0.3w ≤ b ≤ 0.5w].

Here, the dimension setting of [w <W ≦ 1.3w] is a result of investigating the assembling property of the boot band 3 in the band groove 4 and the fixing property of the boot band 3 in the band groove 4. . In this case, w <W is natural and W ≦ 1.3w
When the width W exceeds 1.3 w, the rattling in the band groove 4 of the boot band 3 becomes large and the fixability deteriorates, and the tightening force when tightening the boot fixing portion 1 to the mating member 2 is set. There is a possibility that the balance will be lost and tightening failure will occur. In order to further improve the fixing property of the boot band 3, it is desirable to set the dimension of [1.01w <W ≦ 1.2w], and this dimension setting is most effective in the range of w = 5 to 20 mm. It is known as a result of the experiment.

The dimension setting of [0.9b≤e≤b] is for fitting the convex portion 12 of the boot fixing portion 1 into the engaging groove 21 of the mating member 2 with good matching. The cross-sectional shape of the convex portion 12 in the axial direction may be an arc shape, a trapezoidal shape, or the like. The convex portion 12 fits into the engagement groove 21 with good matching, and is positioned with respect to the force in the X direction when tightening the band. The upper limit of the width e for preventing the deviation is naturally b, and the lower limit is 0.9b.
It has been found that the preferable lower limit is 0.95b.

If the height f of the convex portion 12 is too low, the positional deviation restraining force against the force in the X direction at the time of band tightening is insufficient, and if it is too high, problems of boot formability and boot assembling occur. . Therefore, the height f of the convex portion 12 should not exceed the depth a of the engagement groove 21 of the mating member 2. This will be described later.

The setting of [0.3w ≦ b ≦ 0.5w] is determined from the distribution tendency of the tightening force of the boot band 3. When the center line of the band groove 4 and the center line of the convex portion 12 are aligned with each other and the boot band 3 of the band groove 4 is tightened, the tightening force is strongest in the center part in the band width direction and decreases as it approaches the end of the band. (In particular, the caulking type boot band that has an Ω (omega) shaped clamp part that is commonly used as a boot band for resin boots has a structure that has a marked difference in tightening force in the band width direction. Is). Therefore, when the boot fixing portion 1 is fastened to the mating member 2 by the boot band 3, the tightening force is most effectively and strongly applied to the engaging groove 21 and the protruding portion 22 of the mating member 2. It is desirable to tighten the engaging groove 21 at the central portion, and for that purpose, it is effective to set b ≦ 0.5w. On the other hand, the width b of the engaging groove 21 is
If it is less than 0.3 w, it becomes particularly difficult to form the engaging groove 21 and the manufacturing cost of the mating member 2 increases.

The present invention pursues the workability of the constituent members and the biteability of the mating member 2 into the boot fixing portion 1 when the band is fastened as a result of the above dimension setting, and as a result, the protrusion from the inner circumference 11 of the boot fixing portion 1 is obtained. Between the height f of the portion, the depth a of the engaging groove 21 of the mating member 2, and the height c of the protrusion 22, [0.2 mm
Set the dimensional range of ≤c≤0.5mm], [0.5mm≤a≤1.5mm], and the dimensional relationship of [f≤ (ac)], [(b / a) ≥3].

That is, if the height c of the projection 22 of the mating member 2 is too small, the inner circumference 11 of the boot fixing portion 1 strongly contacts the outer circumference 23 of the mating member 2 when the band is tightened, and the boot of the projection 22 is booted. It is not possible to expect a sufficient bite into the fixed part 1. Therefore, when the lower limit value of the height c at which the protrusion 22 can be expected to bite into the boot fixing portion 1 sufficiently well is calculated,
It was found that a lower limit of 0.2 mm is suitable.

On the contrary, if the height c of the protrusion 22 is too large, the material diameter of the mating member 2 must be increased, which increases the material cost and the processing cost.
When the boot fixing portion 1 is fixed, a gap may be created between the boot fixing portion 1 and the outer periphery 23 of the mating member 2, dusts may be accumulated, and the sealability may be deteriorated.
If the height c is too large, in the case of the resin boot, the selection width of the diameter of the mating member 2 and the tightening margin of the inner diameter of the boot fixing portion 1 becomes narrow, and the outer diameter of the mating member 2 and the boot fixing portion 1 become smaller.
If the inner diameters of the two are matched, the assembling properties of the both may become extremely poor. When the optimum upper limit value of the height c under each condition was obtained, it was found that 0.5 mm was appropriate.

The size regulation of [0.5 mm ≦ a ≦ 1.5 mm] is based on the following reason. The depth a of the engaging groove 21 of the mating member 2 is
It is desired that the convex portion 12 does not come into contact with the bottom of the engaging groove 21 when the band is tightened. That is, the convex portion 1 when tightening the band
When 2 comes into contact with the bottom of the engagement groove 21 and is elastically deformed, the biting property of the protrusion 22 is reduced by the reaction force of the deformation. On the other hand, if the depth a is too large, the strength of the engaging groove 21 will be reduced, and it will be difficult to copy the engaging groove 21, which will be disadvantageous in manufacturing cost and workability. On the other hand, if the depth a is too small, the height f of the protrusion 12 must be reduced accordingly, and the effect of fixing the position of the protrusion 12 in the engagement groove 21 is reduced. From the above, the depth a of the engagement groove 21 is
0.5 mm or more is suitable to improve the position fixing of the convex portion 12, and 1.5 mm or less is suitable to improve the copying workability.

Further, the relationship between the depth a of the engaging groove 21 and the height f of the convex portion 12 is that the convex portion 12 is engaged with the engaging groove 21 when the band is tightened.
It is necessary to avoid contact with the bottom of the ridge, or to prevent the bite of the protrusion 22 from being affected by such contact. In this relationship, the height c of the protrusion 22 and the material of the boot are also related, and in consideration of these, the height f of the protrusion 12 and the engagement groove 21 are taken into consideration.
When the optimum dimensional relationship between the depth a and the height c of the protruding portion 22 was obtained, the relationship of f ≦ (ac) was found.

The dimensional relationship of [(b / a) ≧ 3] is
Similar to the mounting structure shown in FIG. 7, the engaging groove 21 is shaped so as to be capable of being profiled so as to improve workability and reduce manufacturing cost.

The effect of the dimension setting and the dimension relationship setting at each part of the boot mounting structure is that the engaging groove 2 of the mating member 2 is effective.
A slight difference can be seen depending on the cross-sectional shape in the axial direction of 1. That is, the cross-sectional shape of the engaging groove 21 in the axial direction is suitable as shown in FIGS. 2, 3, and 4. Engagement groove 21 of FIG.
Has a flat surface 21m whose central portion is parallel to the axis, and a circular arc surface 21n is continuous from the flat surface 21m toward the vertices of the protrusions 22 on both sides of the engaging groove 21. Engagement groove 2 of FIG.
No. 1 has a flat surface 21'm whose entire bottom is parallel to the axis. The engaging groove 21 in FIG. 4 is an arc surface 21′n having a radius of curvature R ′ as in the case of FIG.

Considering the biteability of the protrusion 22 into the boot fixing portion 1 by the engagement groove 21 of each shape shown in FIGS. 2 to 4, the biteability of FIG. 2 is better than that of FIG. The biteability of FIG. 3 is better than that of FIG. However, in the shape of the engaging groove 21 of FIG. 3, problems may occur in stress concentration and workability of the flat surface 21 ′ m and the corner portion of the protrusion 22. Here, in consideration of the biting property and the workability, the best one is the engaging groove 21 having the shape shown in FIG. 2, and a better shape of the engaging groove 21 is that the radius of curvature of the arc surface 21n is R. Then, the size range is set to [0.1 mm ≦ R ≦ a]. That is, when the radius of curvature R is smaller than 0.1 mm, the biteability increases as in FIG. 3, but the workability deteriorates. On the contrary, when the radius of curvature R exceeds the dimension of the depth a of the engaging groove 21, the workability is improved but the biting property is deteriorated.

[0037]

According to the present invention, by setting the size of the band groove width and the boot band width of the boot fixing portion and setting the width of the convex portion with respect to this band width, the boot fixing portion is always the best mode in the boot band. It is possible to tighten with, and by setting the dimensions of the convex part of the boot fixing part, the engaging groove of the mating member and the protruding part, the engaging property of the convex part and the engaging groove at the time of band tightening,
Since the protrusions always bite into each other optimally, it is possible to reliably secure high retaining strength and sealability of the boot fixing portion. Such high sealing performance can be ensured in a wide variety of constant velocity universal joints and boots, and in particular, resin boots can be used with fixed type constant velocity universal joints that can be used up to a high turning angle for front wheel outboard of automobiles. It is also effective in the boot mounting structure used. In addition, the method for forming the boot fixing portion is not limited, and the engaging groove of the mating member can also be copied,
The manufacturing cost can be easily reduced, and the workability of attaching the boot fixing portion to the mating member can be improved.

[Brief description of the drawings]

FIG. 1 (A) is a sectional view showing the periphery of a boot fixing portion according to an embodiment before band tightening, and FIG. 1 (B) is a sectional view after band tightening.

FIG. 2 is a sectional view of a boot fixing portion and a side view of a mating member according to the embodiment of FIG.

FIG. 3 is a side view showing the periphery of an engagement groove of a mating member according to another embodiment.

FIG. 4 is a side view showing the periphery of an engagement groove of a mating member according to another embodiment.

FIG. 5 is a cross-sectional view showing the periphery of a boot fixing portion according to a conventional configuration.

FIG. 6 is a cross-sectional view showing the periphery of a boot fixing portion according to another conventional configuration.

FIG. 7 (A) is a cross-sectional view before tightening the band showing the periphery of the boot fixing portion of the boot mounting structure which is the premise of the present invention, and FIG. 7 (B) is a relationship of the mating member in FIG. 7 (A). It is a side view which shows the periphery of a compound groove.

[Explanation of Codes] 1 boot fixing part 2 mating member 3 boot band 4 band groove 11 inner circumference 12 convex part 21 engaging groove 22 protruding part 23 outer circumference w boot band width W band groove width e convex part width f convex part height a Engagement groove depth b Engagement groove width c Projection height

Claims (2)

[Claims] 1. An annular band groove is formed on the outer circumference of a cylindrical boot fixing portion that constitutes an end of the boot, and an annular band groove is formed integrally with a portion of the inner circumference of the boot fixing portion facing the band groove. On the other hand, on the outer periphery of the mating member which forms the convex portion and on which the boot fixing portion is fitted and fixed, an annular engaging groove into which the convex portion is fitted, and mating members on both sides of this engaging groove. A boot band formed by forming an annular protrusion projecting from the outer periphery, fitting the boot fixing portion to the outer periphery of the mating member by fitting both protrusions and the engaging groove, and fitting in the band groove on the outer periphery of the boot fixing portion. In the boot mounting structure in which the boot fixing part is tightened and the inner circumference of the boot fixing part is elastically deformed by this tightening force to be airtightly fixed to the outer periphery of the mating member, the band groove of the boot fixing part and the widthwise center of the convex part The width of the band groove at the position where the center lines are almost opposite W, the width of the boot band is w, the width of the convex portion e, the width of the engaging groove of the mating member b, [w <W ≦ 1.3w], [0.3w ≦ b ≦
0.5w], [0.9b ≦ e ≦ b], and the height of the convex portion from the inner circumference of the boot fixing portion is f and the depth of the engaging groove of the mating member is a. Assuming that the height of the protrusions on both sides of the groove from the outer periphery of the mating member is c, [0.2 mm ≤ c ≤ 0.5 m
m], [0.5 mm ≤ a ≤ 1.5 mm], and further, [f ≤ (ac)], [(b / a) ≥ 3]. Boot mounting structure. 2. The engaging groove of the mating member is a flat surface whose central portion is parallel to the mating member axis, and the arcuate surface is continuous from this flat surface toward the apexes of the protrusions on both sides of the mating groove. , The radius of curvature R of the circular arc surface on at least one side of the flat surface is
The boot mounting structure according to claim 1, wherein the size is [0.1 mm≤R≤a].