JP2000297825A - Divided type boot, joining method therefor, welding agent and heating body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve seal performance and fatigue strength at divided end parts joined each other of a divided type boot and to improve workability at the time of mounting the boot. SOLUTION: A projecting streak 16 formed at a divided end part 14 of a boot is temporarily coupled with a recessed streak 17 formed at the other divided end part 15 in engaged states of engaging difference of level parts 162a, 172a each other formed on the one side and is joined with the recessed streak 17 by welding, fusion or adhesion. By joining a polymerized projecting streak 173 formed on a non-engaged side (an inner peripheral side) of the recessed streak 17 by striding the streak 173 over an inner peripheral surface 16a of the projecting streak 16 and an inner peripheral surface 14b of the divided end part 14 continuous to this inner peripheral surface 16a, large joining area is secured. Because the projecting streak 16 is engaged on only one side, the insertion resistance is reduced. Because the polymerized projecting streak 173 becomes a guide at the time of the insertion, a temporary coupling work becomes easy. Thickness of the divided end parts 14, 15 is reduced and fatigue durability can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boot used for sealing an operating part such as a universal joint, and more particularly to a boot having a partly divided circumferential direction. Etc. that can be attached from the side.

[0002]

2. Description of the Related Art In a boot of this type, a flexible portion formed in a bellows-like shape of a boot is flexibly expanded and contracted by attaching mounting portions at both axial ends to, for example, an outer race and a joint shaft of a universal joint. While preventing foreign matter from entering the operating portion of the universal joint, the oil and fats such as grease filled in the operating portion are sealed.

[0003] One type of the boots is a split type.
In a split type boot according to the prior art, a rubber boot is divided at a part in the circumferential direction, and a plurality of male couplings respectively arranged at predetermined intervals at split ends facing each other in the circumferential direction. A fastener comprising a member and a female coupling member is provided integrally. In other words, at the time of mounting, the split ends are opened from the side to cover a universal joint or the like, and the fasteners are bonded and bonded with an adhesive so that the split ends are closely joined to each other. It has become.

[0004]

The boot is rotated by rotating the outer race, to which the mounting portions at both ends in the axial direction are fixed, and the joint shafts in a state where they are inclined with respect to each other.
The bellows portion repeats the bending and stretching operation every half cycle of rotation. In the case of the split type boot, if the split end portions bonded to each other are repeatedly bent and stretched, the hardened adhesive layer may cause cracks or the like due to fatigue, and the grease in the universal joint may leak at an early stage. Is pointed out. In addition, it is necessary to provide the male and female coupling members of the fastener at the divided ends with high precision, and since this fastener has low sealing performance, it is necessary to secure the sealing performance by applying a coating agent or the like. In addition, it is pointed out that the boot may be damaged in a short period of time due to poor followability of the boot in bending and stretching deformation.

SUMMARY OF THE INVENTION The present invention has been made under the above circumstances, and its main technical problems are to improve the sealing performance and fatigue strength at the divided end of a split type boot, The object is to improve workability at the time of mounting.

[0006]

The above technical problems can be effectively solved by the present invention.

First, the split type boot according to the first aspect of the present invention is a cylindrical boot having one portion divided in the circumferential direction, and is divided in a circumferential direction so as to be opposed to each other and integrally joined when mounted. A ridge and a ridge extending along the cross-sectional shape of the boot are formed at the ends, and the ridge on one of the divided ends and the concave on the other divided end are engaged with each other on one side in the thickness direction. The convex ridge is formed on the non-engagement side of the concave ridge so as to protrude longer than the convex ridge, and is formed so as to be joined over the one divided end. Further, in this configuration, more preferably, the mounting portions at both ends in the axial direction of the boot are formed of a rubber-like elastic material having a higher elasticity than the boot, and the outer peripheral surface of the mating member is separated through a packing that is divided at one location in the circumferential direction. Attached to.

According to a second aspect of the present invention, there is provided the split type boot according to the first aspect, wherein the end of the overlapped ridge at the valley portion of the bellows portion of the boot is the other split end. Is formed at the same position in the circumferential direction as that of the end face, or is set back in the circumferential direction from this end face.

A split type boot according to a third aspect of the present invention is a tubular boot having one portion divided in a circumferential direction, the divided ends being opposed to each other in a circumferential direction and integrally joined to each other when mounted. A convex ridge and a concave ridge extending along the axial cross-sectional shape of the boot are formed on each of the portions, and the convex ridge on one of the divided ends and the concave ridge on the other divided end engage with each other on one side in the thickness direction. And the ridges on the bellows of the boot and the slope connecting the ridges and valleys on the non-engagement side of the ridges, the ridges projecting longer than the ridges and An overlapped ridge is formed so as to be joined over the one divided end.

A split boot according to a fourth aspect of the present invention is provided with an open portion in which one portion on the circumference is split, and is mounted by covering a mounting member such as a universal joint and joining the open portion. Wherein the open portion is joined by welding while being heated by a heating element having self-heating properties.

According to a fifth aspect of the present invention, there is provided a method for joining a split-type boot, comprising an open portion obtained by dividing one portion on a circumference, and joining the open portion after covering a mounting member such as a universal joint. A method of joining split-type boots to be mounted by contacting or approaching a heating element having self-heating properties to the opening, and welding while heating the opening with the heating element. I do.

Further, the welding agent according to claim 6 of the present invention comprises:
A welding agent used when joining a split-type boot, which is provided with an open portion obtained by dividing one portion on a circumference and covers a mounting member such as a universal joint, and then joining the open portion. The coating is applied to a facing surface of the opening to weld the facing surface.

Further, the welding agent according to claim 7 of the present invention comprises:
The above-mentioned welding agent according to claim 6, wherein the welding agent comprises a solvent that dissolves the thermoplastic elastomer.

Further, the welding agent according to claim 8 of the present invention comprises:
The above-mentioned welding agent according to claim 6, wherein the welding agent is dimethylformamide, tetrahydrofuran, toluene,
It is characterized in that a solvent of ethyl acetate, methyl ethyl ketone, acetone, cyclohexanone, dichloromethane is used alone or in combination.

[0015] The heating element according to claim 9 of the present invention comprises:
A heating element which is provided with an open part obtained by dividing one part on the circumference, covers a mounting member such as a universal joint, and then joins a split-type boot attached by joining the open part. And has self-heating properties, and is fixed to the boot and heat-welds the open portion in contact with or close to the open portion.

According to a tenth aspect of the present invention, there is provided the heating element according to the ninth aspect, wherein the heating element is deformed following the bellows shape of the boot. Characterized in that a heat-generating component is contained in the heat-generating device.

Still further, the heating element according to the eleventh aspect of the present invention is the heating element according to the ninth aspect, wherein the heating element is in close contact with the opening along the bellows shape of the boot.
An uneven shape along the unevenness of the bellows is previously formed on the outer surface of the heating body.

According to the split-type boot according to the first aspect of the present invention having the above-described configuration, the divided portions of the boots joined to each other in the state of being mounted on the mounting member such as the universal joint ensure a good sealing property. . This is because the ridges and the ridges extend continuously at the divided ends of the boot, and their mating surfaces are integrated by welding, fusion or adhesion, and This is because a large joint area is secured by forming the convex ridge and the overlapping convex ridge that is joined across the one divided end portion continuous to the convex ridge on the non-engagement side of the ridge.

Further, since the protruding ridge is shaped to be engaged with the concave ridge on one side in the thickness direction, the divided end portion is made thinner as compared with the case where the engaging portion is formed on both sides in the thickness direction. Can be. For this reason, by inserting and engaging the convex ridge with the concave ridge, the insertion resistance at the time of temporarily joining the divided ends is reduced, and the overlapping convex ridge serves as a guide at the time of insertion. Can be easily performed, and an increase in stress due to repeated bending and stretching deformation is suppressed, so that fatigue durability is improved.

In the case where the mounting portions at both ends in the axial direction of the boot are mounted on the outer peripheral surface of a mating member such as a universal joint via packing formed of a rubber-like elastic material which is more elastic than the boot, It is possible to improve the sealing property in the part.

If the overlapping ridges in the boot according to the first aspect are provided over the entire length of the bellows portion of the boot, there is a tendency that the thickness of the joint portion tends to increase. Since the stress on the outer surface of the valley portion of the bellows portion is large, there is a concern that a crack may be generated early at this portion. Therefore, in such a case, like the boot according to claim 2 of the present invention, the end of the overlapped ridge at the valley portion of the bellows portion of the boot is located at the same circumferential position as the end surface of the other divided end or It is preferable to form it so as to retreat in the circumferential direction from this end face. In this case, the thickness of the joint at the valley is reduced,
The generated stress can be reduced. Further, as in the boot according to the third aspect, on the non-engagement side of the concave streak, on the peak of the bellows portion, and on the slope connecting the peak and the valley, the protrusion protrudes longer than the protruding streak and one of the protruding streaks. The same operation and effect can be obtained by forming a polymerized ridge that is joined over the divided ends.

Further, the present invention has the above configuration.
In the boots according to the above, the boot is manufactured without attaching a fastener to the facing surface of the opening, and when the boot is mounted on the outer periphery of a mounting member such as a universal joint, a welding agent is applied to the facing surface of the opening. To weld the opposing surfaces together. Further, when the open portion is welded in this way, the open portion is welded while being heated by a heating element having self-heating properties, thereby promoting a welding reaction or a joining reaction. The open portion joined by welding has excellent sealing properties because the opposing surfaces are integrated with each other, and can be freely deformed following the deformation of the bellows portion. Having self-heating means that the device itself generates heat when used, and does not require external energy supply such as electric power to generate heat. In order to ensure excellent jointability by welding, it is preferable to use a thermoplastic elastomer as the material of the split-type boot. Particularly, in order to sufficiently exhibit the performance as a boot, polyurethane having high strength and excellent durability is used. It is preferable to use a thermoplastic thermoplastic elastomer or a polyester thermoplastic elastomer.

Further, in the method for joining boots according to the fifth aspect of the present invention, a boot is manufactured without attaching a fastener to a surface facing the open portion, and the boot is mounted on the outer periphery of a mounting member such as a universal joint. In some cases, a welding agent is applied to the facing surfaces of the open portions to weld the facing surfaces to each other. In addition, when the opening is welded in this way, a heating element having self-heating properties is brought into contact with or close to the opening, and welding is performed while heating the opening with this heating element, thereby accelerating the welding reaction or joining reaction. Let it. The open portion joined by welding has excellent sealing properties because the opposing surfaces are integrated with each other, and can be freely deformed following the deformation of the bellows portion. Heating elements with self-heating properties include iron powder,
It is preferable to use water, activated carbon, salt, or metal oxide and water as main components, which generate heat mainly by an oxidation reaction or a reduction reaction. If it is, it can be used.

Further, in the present invention, the heating element used for joining the open portions is a bag having air permeability such as paper, non-woven fabric or cloth, and iron powder, water, activated carbon and salt, or metal oxide and water. When the outer bag of the shielding film that wraps the heating element is opened, the moisture in the air touches the iron, and this iron causes an oxidation reaction. Alternatively, the metal oxide and water react to cause a reduction reaction. Therefore, high heat is generated with this,
This high heat makes it possible to heat-weld the opening. In addition, even though there are irregularities (peaks and valleys) due to the bellows on the outer surface of the boot, the heating element transfers the heat to the opening so that the heating element can be transferred to the open part. It is preferable that the heating element is housed in close contact with the entire outer surface of the open portion by accommodating the heating element or by shaping the outer surface of the heating element in advance in accordance with the unevenness of the bellows. As a result, the heating element closely contacts or approaches not only the convex part (peak part) but also the concave part (valley part) of the bellows, and the temperature of the concave part rises without changing much as the temperature of the convex part. It is possible to raise the overall temperature normally, which in turn makes it possible to reduce the welding time.

Also, for example, if a dryer that blows hot air is used to heat the open portion, a person must hold the dryer and work by cutting with the dryer until the welded portion is sufficiently dried. A restraining means must be provided separately so that the opening does not open on the way, and the opening must be kept closed. In addition, when the hot air is blown by the dryer, there is a possibility that a large variation in temperature occurs between a portion where the hot air is blown and a portion where the hot air is not blown. On the other hand, if the heating element is fixed to the outer surface of the open portion of the boot and welding is performed, the work can proceed without a human being at the time of drying, and there is no need to separately provide a restraining means. Also, it is possible to maintain the open portion in the closed state until the welded portion dries, and it is easy to keep the heating temperature constant. In addition, external heat energy sources such as power supply equipment and heat-generating lights are not required. As a method of fixing the heating body to the outer surface of the open part of the boot, an adhesive sheet,
It is preferable to use attachment means such as an adhesive tape, a knot, an elastic cloth, or a magic tape.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment FIGS. 1 to 3 show a preferred embodiment of a split-type boot according to the present invention. First, in FIG. 1, reference numeral 1 denotes a boot entirely formed of a thermoplastic elastomer.

The thermoplastic elastomer is abbreviated as TPE, as is well known, and has the property of an elastomer (rubber-like elastic material) at room temperature and exhibits plastic fluidity at high temperature, that is, at room temperature. Has a molecular structure or a micro-dispersed structure in which a rubber component having entropy elasticity and a constraining component for preventing plastic deformation are combined, and has excellent ozone resistance, strength, cold resistance, grease resistance,
For example, there are polyurethane thermoplastic elastomer (TPU) and polyester thermoplastic elastomer (TPEE) having fatigue resistance.

In the present embodiment, preferably, the boot 1
As the material, a polyurethane thermoplastic elastomer having excellent strength, ozone resistance and fatigue durability as compared with a normal rubber material is used. In addition, the number average molecular weight is 15
A polyether-type polyurethane-based thermoplastic elastomer obtained by reacting a polyoxymethylene glycol of from 0 to 2500 with a chain extender and an organic diisocyanate, and having a melt viscosity at a temperature of 200 ° C of 0.5 × 10 ⁴ to 1 Those having a density of 0.0 × 10 ⁶ poise are excellent in water resistance and moldability, and are more preferable. In this case, for example, the NCO index (NCO equivalent number / OH equivalent number) of the polyoxymethylene glycol, the chain extender, and the organic diisocyanate is 1.0 to 1.1, and the chain extender has, for example, 2 carbon atoms. And a low molecular weight diol of 10 to 10, and the organic diisocyanate is, for example, 4,4'-diphenylmethane diisocyanate.

The boot 1 has a small-diameter mounting portion 11 formed at one end in the axial direction, a large-diameter mounting portion 12 formed at the other end in the axial direction, and a circumferential direction between the two mounting portions 11 and 12. And a thin-walled bellows portion 13 in which a valley portion 13a and a valley portion 13b are formed repeatedly. The mounting part 11, 1
2 are formed on the outer peripheral surface thereof with band mounting grooves 11a and 12a extending in the circumferential direction. The band mounting grooves 11a and 12a are respectively provided with the mounting portions 11 and 12, for example, a joint shaft of a universal joint and an outer joint. A band is wrapped around the outer peripheral surface of the race for binding.

As shown in FIG. 2, which is a cross-sectional view taken along the line II-II 'in FIG. 1, the boot 1 is divided at one location in the circumferential direction, and divided ends 14 facing each other on both circumferential sides. , 15 have a shape in which the portion extending the bellows portion 13 has an increased thickness toward the inner peripheral side, that is, is formed to be appropriately thicker than the bellows portion 13.

A protruding ridge 16 is formed at one of the divided ends 14 of the boot 1 in a direction opposite to the other divided end 15. Corresponding groove-shaped concave stripes 17 are formed. These ridges 16
The ridge 17 extends along the entire length of the bellows portion 13 in the axial direction along the cross-sectional shape of the boot 1.

As shown in FIG. 3, the ridges 16 are
And a head 162 formed at the tip of the neck 161 protruding from a position eccentrically located on the inner periphery of the end surface 14a of one of the divided ends 14, and the head 162 is formed on the outer peripheral surface 161a of the neck 161. And an outer peripheral tapered surface 162b that becomes smaller in diameter from the outer peripheral edge of the engaging step 162a toward the tip 162c. The inner peripheral surface 16a of the ridge 16 forms a flat surface that is continuous with the inner peripheral surface 14b of the one divided end portion 14.

The concave ridge 17 has a sectional shape corresponding to the above-mentioned convex ridge 16, that is, the end face 1 of the other divided end 15 facing one of the divided ends 14.
5a, a head receiving portion 171 extending from the neck receiving portion 171 and a head receiving portion 172 extended therefrom.
Numeral 72 designates an engaging step 172a which rises from the outer diameter surface 171a of the neck receiving part 171 to the outer peripheral side, and the engaging step 172a.
An outer diameter tapered surface 172b having a smaller diameter from the outer peripheral edge of 72a toward the inside of the divided end portion 14 is provided. Also,
The inner peripheral side of the concave ridge 17 is formed by overlapping the convex ridge 1 extending toward the one of the divided ends 14 longer than the projecting length of the convex ridge 16.
73, and its outer peripheral surface 173a is
Inner peripheral surface 16a and one of the divided ends 1 continuous therewith
4 is formed corresponding to the inner peripheral surface 14b.

The ridge 16 has one side in the thickness direction (outer circumference side).
Is formed only on the ridge 1 and the concave ridge 17 has a corresponding shape, so that as shown in FIG.
Compared to the case where the engaging step portions a and b are formed on both the outer periphery and the inner periphery of the concave strip 6 'and the concave strip 17', the divided end 1
4, 15 can be reduced in thickness t.

As shown in FIG. 1, grommets 2 and 3 as packings are arranged on the inner periphery of the mounting portions 11 and 12 at both ends in the axial direction of the boot 1, respectively. The grommets 2 and 3 are more elastic than the thermoplastic elastomer forming the boot 1 and have superior properties to oil resistance, cold resistance and compression set, for example, NBR (nitrile rubber).
And at least one portion in the circumferential direction is divided similarly to the boot 1.

The grommet 2 arranged on the inner circumference of the mounting portion 11 on the small diameter side of the boot 1 has the mounting portion 11 on its outer peripheral surface.
A band-shaped fitting groove 21 that can be fitted to the inner peripheral portion of the seal is formed, and a seal ridge 22 continuous in the circumferential direction is formed on the inner peripheral surface. Similarly, the grommet 3 arranged on the inner periphery of the attachment portion 12 on the large diameter side of the boot 1 has the attachment portion 12 on its outer peripheral surface.
A fitting step portion 31 capable of fitting with the inner peripheral portion of the seal member is formed, and a seal ridge 32 continuous in the circumferential direction is formed on the inner peripheral surface.

As described above, the split-type boot having the above-described structure is mounted, for example, as a sealing means for a universal joint (not shown). At the time of this mounting, the split part of the boot 1 is opened, and the universal joint is laterally mounted so that the small diameter side mounting part 11 is on the joint shaft side of the universal joint and the large diameter side mounting part 12 is on the outer race side. 3A, and the projection 16 of the one divided end 14 and the concave ridge 17 of the other divided end 15 are inserted and fitted from the separated state shown in FIG. 3A as shown in FIG. 3B. Thereby, the divided ends 14 and 15 are temporarily connected to each other.

In the above-mentioned provisional joining process, the ridge 16 becomes the concave 1
7 is guided by an overlapping projection 173 that protrudes long from the inner circumference toward the divided end portion 14 side. When the head 162 of the ridge 16 is inserted into the neck receiving portion 171 of the ridge 17, the ridge 17 is deformed so as to be once opened by interference with the outer peripheral tapered surface 162 b of the head 162, By completely inserting the head 162 into the head receiving portion 172 of the concave streak 17, the convex streak 16 and the concave streak 17 are substantially closely fitted to each other as shown in FIG. . As shown in FIG. 2, the boot 1 made of a thermoplastic elastomer is formed to have a shape in which a divided portion is opened to a certain extent, so that the boot 1 attempts to open due to the elasticity of the thermoplastic elastomer. In the state shown, since the engaging step portions 162a and 172a are engaged with each other, the temporary connection state is maintained.

A grommet 2 is arranged on the outer peripheral surface of the joint shaft of the universal joint so as to be hugged from the side.
The mounting portion 11 on the small diameter side is arranged such that an inner peripheral portion is fitted into a band-shaped fitting groove 21 formed on an outer peripheral surface of the grommet 2 and a metal band wound around the band mounting groove 11a. Tied up by Similarly, the grommet 3 is arranged on the outer race outer peripheral surface of the universal joint so as to hug it from the side, and the mounting portion 12 on the large diameter side of the boot 1 has an inner peripheral portion formed on the outer peripheral surface of the grommet 3. It is arranged so as to fit with the formed fitting step 31 and is tied up by another metal band wound around the band mounting groove 12a.

That is, the mounting portions 11 and 12 of the boot 1 made of a thermoplastic elastomer are provided with grommets 2 and 3 made of nitrile rubber or the like, which is well compatible with a mating material and has high elasticity.
Is fixed to the outer peripheral surface of the joint shaft of the universal joint and the outer peripheral surface of the outer race. In particular, the mounting portions 11, 1
The grommet 2 and the grommets 2 and 3 are tightly fitted in a concave and convex fitting state by the binding force of the metal band from the outer periphery, and the outer peripheral surface of the joint shaft and the outer race at the sealing ridges 11b and 12b of the grommets 2 and 3. A good sealing state can be obtained by locally increasing the sealing surface pressure with respect to.

The divided ends 14, 15 temporarily joined by inserting and engaging the ridges 16 and the recesses 17 with each other,
For example, joining is performed by a method of welding using a welding agent. In this case, the welding agent is preliminarily divided into the divided ends 14, 1.
5 are dropped and spread over the joint surfaces of the ridges 16 and the concave ridges 17 and the overlapping ridges 173. As a result, the thermoplastic elastomer in the surface layer portion of the joining surface temporarily melts, and a continuous thermoplastic elastomer structure is formed by evaporating the welding agent, whereby an integrated joining state is obtained.

When the boot 1 is formed of a polyurethane thermoplastic elastomer of the polyether type, the polyurethane thermoplastic elastomer is dimethylformamide as a welding agent used for joining the divided ends 14 and 15. And tetrahydrofuran (TH
F) and dissolved in a solvent consisting of a mixture of
a · s) Those adjusted to 100 to 10,000 are preferred. That is, by adjusting the viscosity in this way, dripping hardly occurs during application of the solvent, and the workability can be improved. Further, as the solvent,
Ethyl acetate, acetone, methyl ethyl ketone (ME
K), a mixed solvent in which cyclohexanone, chloroform or the like is added in a small amount to the dimethylformamide can also be used.

As a method of joining the divided ends 14 and 15 temporarily joined by the ridges 16 and the recesses 17, the above-described means such as welding with a welding agent or bonding with fusion dope cement by heating can also be adopted. . Among these, in the joining by fusion, the divided ends 14, 1
A method of temporarily heating the fitting portion 5 or applying high frequency vibration is preferable. That is, the thermoplastic elastomer on the fitting surface of the convex ridges 16 and the concave ridges 17 is temporarily melted by heating to form a continuous thermoplastic elastomer structure, thereby joining them.

By the above-mentioned operation, the divided ends 14 and 15 of the boot 1 are integrally joined to each other, and in particular, a large joining area is secured by the overlapping ridge 173.
It is possible to effectively prevent grease inside the universal joint from leaking from the joint between the divided ends 14 and 15 or muddy water and dust from entering from the joint between the divided ends 14 and 15 from the outside. . The divided end portions 14 and 15 are formed thicker than the bellows portion 13, but as described above, the cross-sectional shape is thinner and more flexible than that of the mushroom-shaped engagement structure shown in FIG. It is possible to secure a flexible bending and stretching property. Moreover, for this reason, the divided ends 14, 15
, And the early peeling of the joint surface can be prevented.

Even if the divided ends 14 and 15 are made thinner, the overlapping projections 17a are provided over the entire length of the bellows portion 13 of the boot 1 so that the bellows portion 13 is formed. When there is a concern that a crack due to stress concentration may occur in the valley 13b, it is effective to take the following measures.

That is, first, as shown in FIGS. 5 and 6, the end 173a of the overlapping ridge 173 at the valley 13b of the bellows 13 of the boot 1 is circumferentially aligned with the end face 15a of the other divided end 15. The circumferential length of the overlapping ridge 173 at the valley 13b (FIG. 6)
(See (B)) the peak 13a, the peak 13a and the valley 13
6A is shorter than the circumferential length of the overlapping ridge 173 (see FIG. 6 (A)) at the slope 13c connecting to the slope 13c, whereby the thickness of the divided ends 14, 15 at the valley 13b is substantially reduced. (Second embodiment).

Alternatively, as shown in FIG.
The end 173a of the overlapping ridge 173 in the valley 13b of the bellows portion 13 is formed so as to retreat in the circumferential direction from the end surface 15a of the other divided end portion 15, thereby forming the overlapping ridge 173 in the valley 13b. Circumferential length (see Fig. 7 (B))
Are overlapped ridges 173 at the peak 13a and the slope 13c.
(See FIG. 7 (A)), thereby substantially reducing the thickness of the divided ends 14, 15 in the valley 13b (third embodiment).

Alternatively, as shown in FIG. 8 and FIG. 9, the overlapping ridges 173 are originally provided only on the peak 13a and the slope 13c of the bellows 13 of the boot 1 (FIG. 9).
(See FIG. 9A), and do not provide it in the valley 13b (FIG. 9).
(See (B)), thereby substantially reducing the thickness of the divided ends 14 and 15 in the valley 13b (fourth embodiment).

Therefore, the valley 1
If the thickness of the divided ends 14 and 15 in 3b is reduced, stress is less likely to be concentrated on the valley 13b, so that cracks due to stress concentration can be effectively prevented, and the stress on the valley 13b is reduced. Thus, it is possible to improve the fatigue property and extend the life.

According to a comparative test (test conditions are as follows) conducted by the inventors of the present invention, the conventional product was 70 to 11
While the crack was generated by the operation at 5 hours, the prototype of the present invention did not generate the crack even at the operation of 500 hours.

Test conditions: -20 ° C. × 10-20 deg ×
300 rpm x 30 cpm

Further, by forming the joining surface of the divided ends 14 and 15, particularly the joining surface (the groove-side surface) of the other divided end 15, in a rough shape, the wettability of the solvent is ensured, and Can be improved, and the adhesiveness can be improved.

Returning to the description of FIG. 1 to FIG. 3, the boot 1 is formed of a thermoplastic elastomer having excellent strength, ozone resistance and fatigue durability and water resistance as compared with a normal rubber material. Therefore, leakage of grease or the like due to fatigue failure of the joint is unlikely to occur, and excellent durability is exhibited.

In the above embodiment, for example, the grommets 2 and 3 as the packing are attached to the mounting portion 1 of the boot 1.
It is also possible to incorporate them into the inner circumferences of the boots 1 and 12 in advance by means such as fitting, or to integrate them with the boot 1 by bonding or the like.

With respect to a specific example of this embodiment,
A product durability test and a material water resistance test were performed together with the comparative example.

<Example> 660 parts of polyoxymethylene glycol having a number average molecular weight of 1700 and 55 parts of 1,4-butanediol as a chain extender were mixed, and 4,4 ′ was obtained as an organic diisocyanate corresponding to a theoretical amount. Diphenylmethane diisocyanate: Add 252.5 parts and add 160
A split-type boot having the shape shown in FIGS. 1 and 2 was injection-molded using a polyether-type polyurethane-based thermoplastic elastomer obtained by reacting at 10 ° C. for 10 minutes. The split ends 14 and 15 of the boot 1 are joined by welding with a welding agent. As the welding agent, a polyether-type polyurethane thermoplastic elastomer of the same material as that to be joined is dissolved in a solvent composed of dimethylformamide. The viscosity (mPa · s) adjusted to 1000 was used. After the application of the welding agent, it was stably held for 15 minutes.

<Comparative Example> Using a polyolefin-based thermoplastic elastomer (Santoprene 101-87: manufactured by AES Co., Ltd.), a split-type boot having the shape shown in FIGS. 1 and 2 was injection-molded. The split ends 14 and 15 of the boot 1 are joined by welding with a welding agent. As the welding agent, dimethylformamide is used.
It was kept stable for 15 minutes.

Evaluation method Product durability test Each boot of the example and the comparative example produced as described above was attached to a swing rotation test device, and the durability time was measured. The endurance time was determined by the time at which grease leaked from the boot after the start of operation. [Test conditions] Temperature: room temperature Swing angle: 25 to 40 ° Swing cycle: 30 times / min Rotation speed: 600 rpm

The test results were as follows.

First, in the product durability test, in the comparative example, the occurrence of grease leakage was observed 20 minutes after the start of the test, whereas in the example, it took 280 minutes until the grease leakage occurred. It was confirmed that the split-type boot formed of the polyurethane-based thermoplastic elastomer was more excellent in durability.

The same effects as described above can be obtained even if a polyester-type polyurethane thermoplastic elastomer is used as the material of the boot 1. Further, in the illustrated embodiment, the ridge 16 is formed on the outer peripheral side with the concave ridge 17.
However, it is also possible to engage with the concave ridge 17 on the inner peripheral side and to have the overlapping convex ridge 173 on the outer peripheral side of the concave ridge 17.

Fifth Embodiment As shown in FIG.
The split-type boot 1 according to the second embodiment has a tubular shape as a whole, includes an annular small-diameter side attachment portion (also referred to as a fixed portion) 11 at one end opening, and a small-diameter side fixing portion 11 at the other end opening. A larger-diameter annular large-diameter mounting portion 12 is provided,
Further, a bellows portion 13 is integrally formed between the two mounting portions 11 and 12, and the whole is formed of a thermoplastic elastomer. This thermoplastic elastomer is a polyurethane-based thermoplastic elastomer. The boot 1 is provided with an open portion (also referred to as a joint or cut portion) 18 in which one portion on the circumference is divided and opened over the entire length, and the open portion 18 is provided with a self-heating property. It is joined by welding while being heated by a heated body (also referred to as a heating agent, a heating element or a heating agent).

The boot 1 is manufactured without attaching a fastener to the opposing surfaces 18a and 18b of the opening 18, and the opening 1 is opened at the time of mounting, and the boot 1 is put on the universal joint or the like from the opening 18. And then the opening 18
Are attached to the outer periphery of the universal joint. At this time, the small-diameter mounting portion 11 is fixed to the drive shaft by a band, and the large-diameter mounting portion 12 is similarly fixed to the universal joint by a band.

As shown in FIG. 11, the heating element 41 is made of paper,
A heat-generating component (not shown) containing iron powder, water, activated carbon and salt, or a metal oxide and water as main components is housed inside a breathable bag 42 made of nonwoven fabric or cloth. When the outer bag (not shown) made of a shielding film is opened for use, moisture in the air comes into contact with iron, and this iron causes an oxidation reaction or a reduction reaction between metal oxide and water. . Accordingly, high heat is generated along with this, and the open portion 18 can be heated and welded by the high heat. The bag 42 containing the heat-generating component has an irregular shape that can be freely deformed. The bag 42 has an adhesive so that one surface of the bag 42 can fix the heating body 41 to the outer surface of the opening 18 of the boot 1. A heat generating surface 4 that generates high heat on the same surface as an adhesive surface 43 by attaching a sheet or the like.
4 is set.

Although the above-mentioned heating uses a chemical reaction type heat generating material, a phase change type heat storage material which generates heat when the crystalline substance is crystallized from a supercooled state can also be used. An example of the heat storage material is sodium acetate hydrate. Since the former substance is liquid, it is more easily adapted to the shape of the boot.

As shown in FIGS. 12 and 13, the heating element 41 is attached to the outer surface of the opening 18 of the boot 1.
8 so that the opening portion 18 is kept closed so that the opening portion 18 is not opened during the welding operation. Also, the unevenness of the outer surface of the bellows portion 4 of the boot 1 (Yamaya)
The heat generated in the heating element 41 is efficiently transmitted to the opening 18 because the bag 42 is appropriately deformed along with and adheres to the unevenness in a wide area. Therefore, the open portion 18 can be efficiently heated and welded by the high heat that is efficiently transmitted as described above. Also, as shown in FIGS. 14 (A) and 15, irregularities 45 are formed on the outer surface of the heating element 41 in advance,
Even if the uneven shape 45 is arranged in accordance with the unevenness of the outer surface of the bellows portion 4, the heating surface 44 of the heating body 41 can be brought into contact with the boot 1 over a wide area. FIG.
The heating element 41 in FIG. 15A has a plurality of irregularities.
Is provided with one convex portion. In addition, heating element 4
When storing 1, in order to fold the outer surface into an uneven shape as shown in FIG. 14 (B), the outer surface is made of an elastic material, for example, nylon tights, nylon stockings, etc. It is good to pack so that it can be shielded from moisture in the inside.

As the attachment means for fixing the heating element 41 to the outer surface of the boot 1, various fixing means can be considered in addition to the above-mentioned pressure-sensitive adhesive sheet. FIGS. 16 and 17 each show an example. In the example of FIG. 16, as one of the heating elements, a plurality of tying cords 46 are attached to both sides of a heating element 41 such as a commercially-available body warmer. Connect each other. In the example of FIG. 17, a heating element 41 like a commercially available warmer is also used.
A pair of elastic cloths 47 are attached to both sides of the boot 1, and a plurality of magic tapes 48 are attached to the elastic cloth 47. The elastic cloths 47 are wrapped around the outer periphery of the boot 1, and the magic tapes 48 are overlapped and closed. Therefore, in any case, the opening 18 can be kept in a closed state in order to restrain the boot 1 from the outer periphery by the tying string 46 or the elastic cloth 47, and the heating element 41 can move along the unevenness of the outer surface of the bellows 4. In order to deform, the heating surface 4 of this heating element 41
4 can be brought into close contact with the outer surface of the opening 18. The mounting means made of cloth has a heat retaining effect because it is flat and covers the outer periphery of the boot 1, and thereby has an effect of making the temperature of the welded portion uniform and promoting welding.

When mounting the boot 1 on the outer periphery of a mounting member such as a universal joint or the like, first, as described above, the universal joint or the like is covered with the boot 1 and then the welding agent is applied to the opposing surfaces 18a and 18b of the open portion 18. And then the opposite surface 1
8a and 18b are closed, and the opening 18 is closed. Next, the closed state of the opening 18 is maintained using the above-mentioned various attachment means, and the heating element 41 is brought into close contact with the outer surface of the opening 18 to generate heat. When the heating element 41 is removed from the boot 1 after the required time has elapsed, the heating element 41 is removed.
The opening 18 is heated and welded in a relatively short time by the heat generation effect of the above, and the mounting operation can be completed with this.

Therefore, according to this method, the boot 1
In the manufacture of the boot 1, the troublesome work of requiring the fasteners to be accurately attached to the opposing surfaces 18a and 18b of the open portion 18 can be omitted, and thus the manufacture of the boot 1 can be firstly facilitated.

When the boot 1 is mounted, the opening 1
Since it is only necessary to attach the heating element 41 to the outer surface of the heating element 8 and generate heat from the heating element 41, a person can leave the work site during the welding operation. Therefore, the opening 1 of the boot 1
8 or the mounting operation of the boot 1 can be facilitated.

The welded open portion 18 has excellent sealing properties because the opposing surfaces 18a and 18b are integrated by welding. Therefore, the opposing surface 18
The operation of separately applying a coating agent or a sealant or the like to a and 18b can be omitted, and from this point also, the joining operation of the opening 18 or the mounting operation of the boot 1 can be facilitated.

Furthermore, since the welded open portion 18 is freely deformed following the deformation of the bellows portion 4, the boot 1 is also excellent in the deformation followability of the open portion 118. Therefore, the opening 18 can be prevented from being damaged in a short period of time, and its durability can be improved.

Next, the inventors of the present invention conducted a performance comparison test of the welded structure according to the present embodiment, and the details and results will be described below.

The first of these performance tests is that
In the peel test of No. 8, a state in which the joined open portion 18 was peeled by hand was evaluated as follows. ：: No peeling Δ: 50% of the open part peeled ×: All of the open part peeled

The second of the performance tests is an evaluation of the operating condition of the joined open portion 18. After joining, the boot 1 is assembled into a joint, and the open portion 18 is rotated 10 times at a maximum angle of 40 degrees. The state was evaluated as follows. ◎: No opening ○: Very small (2mm or less) one opening △: Very small (2mm or less) Several openings ×: Several openings (2mm or more)

<Example 1> After welding the open portion 18 of the split-type boot 1 made of a polyurethane thermoplastic elastomer material, the heating body 41 shown in FIG.
Hold for 10 minutes.

Example 2 After welding the open portion 18 of the split-type boot 1 made of a polyurethane thermoplastic elastomer material, the heating body 41 shown in FIG.
Hold for 10 minutes.

Example 3 After welding the open portion 18 of the split-type boot 1 made of a polyurethane thermoplastic elastomer material, the heating body 41 shown in FIG.
Hold for 10 minutes.

Example 4 After welding the open portion 18 of the split type boot 1 made of a polyester thermoplastic elastomer material, the heating body 41 shown in FIG.
Hold for 10 minutes.

Comparative Example 1 After the open portion 18 of the split-type boot 1 made of a polyurethane thermoplastic elastomer material was welded, the heating body 41 was held for 10 minutes without touching the open portion 18.

<Comparative Example 2> After the open portion 18 of the split-type boot 1 made of a polyurethane-based thermoplastic elastomer material was welded, the heating body 41 was held for 30 minutes without touching the open portion 18.

<Comparative Example 3> After the open portion 18 of the split type boot 1 made of a polyurethane thermoplastic elastomer material was welded, the heating element 41 was not applied to the open portion 18 and instead was heated by a dryer for 10 minutes.

The test results are as shown in the table of FIG. 18, which confirmed the effectiveness of the present invention.

The welding agent provided by the present invention is as follows.

That is, if the opening 18 of the split-type boot 1 made of a thermoplastic elastomer is to be joined not by welding but by bonding with an adhesive or by heat fusion, there is a concern that the following problems may occur. You.

First, when the opening 18 is bonded with an adhesive, the opening 18 can be bonded, but the adhesive cannot follow the movement of the boot 1. 18 may be peeled off. On the other hand, if the opening 18 is welded with a welding agent as in the present invention, the joint and the boot body are integrated after the welding, so that the joint can follow the movement of the boot 1. Become like

There is no adhesive bonding suitable for actual assembly work (preferably completed within 30 minutes) at a maintenance shop or the like. That is, the instant adhesive type expires before the bonding operation is completed, and the opening 18 cannot be bonded. With a normal adhesive (curable type), it takes about one night to complete the bonding, which is also unsuitable for work. On the other hand, if the opening 18 is welded with a welding agent as in the present invention, the assembling operation can be completed within 30 minutes by adjusting the type and mixing ratio of the solvent. The welding agent provided by the present invention is, as described above, dimethylformamide, tetrahydrofuran, toluene, ethyl acetate, methyl ethyl ketone, acetone, cyclohexanone and dichloromethane solvent alone or mixed, and also dissolves the thermoplastic elastomer To increase the viscosity of the solution. Further, a thermoplastic elastomer is dissolved in a mixed solution of dimethylformamide and tetrahydrofuran to obtain a viscosity of 10 to 10,000 mPa.
S, and a mixed solution of dimethylformamide and tetrahydrofuran, wherein the mixing ratio is dimethylformamide / tetrahydrofuran =
10/90 to 90/10, and the thermoplastic elastomer is dissolved in the solution to increase the viscosity to 10 to 1000.
The working time is adjusted to 0 cps, and by combining these components, the working time can be freely controlled so as to be suitable for actual work.

When the opening 18 is heated and fused, a fusing device (for example, a soldering iron, a drier, a special device, etc.) and a power supply are required. There is also an unfavorable aspect of the work. On the other hand, if the opening 18 is welded with a welding agent as in the present invention, these devices, power supplies, and the like can be eliminated.

Next, the inventors of the present invention conducted a performance comparison test on the welding agent provided by the present invention, and the details and results will be described below.

The first of these performance tests is that
In the peel test of No. 8, a state in which the joined open portion 18 was peeled by hand was evaluated as follows. ：: No peeling Δ: 50% of the open part peeled ×: All of the open part peeled

The second of the performance tests is the evaluation of the operating state of the joined open portion 18. After joining, the boot 1 is assembled into a joint, and the open portion 18 is rotated 10 times at a maximum angle of 40 degrees. Was evaluated as follows. ◎: No opening ○: Very small (2mm or less) one opening △: Very small (2mm or less) Several openings ×: Several openings (2mm or more)

The third of the performance tests is an evaluation of the easiness of the coating operation. The easiness of controlling the coating amount when each of the welding agents is coated on the facing surfaces 18a and 18b of the opening 18 is evaluated. It was evaluated as follows. ：: very good △: somewhat difficult to control, but no problem in work ×: viscosity too high or too low, difficult to control

Example 1 A mixed solution of dimethylformamide and tetrahydrofuran was used as a welding agent in the open portion 18 of the split-type boot 1 made of a polyurethane thermoplastic elastomer material, and the mixing ratio was dimethylformamide / tetrahydrofuran = 10 /. Using 90,
Joined and held for 20 minutes.

Example 2 A mixed solution of dimethylformamide and tetrahydrofuran was used as a welding agent in the open portion 18 of the split-type boot 1 made of a polyurethane thermoplastic elastomer material, and the mixing ratio was dimethylformamide / tetrahydrofuran = 50 / Using 50 things,
Joined and held for 20 minutes.

Example 3 A mixed solution of dimethylformamide and tetrahydrofuran was used as a welding agent in the opening 18 of the split-type boot 1 made of a polyurethane thermoplastic elastomer material, and the mixing ratio was dimethylformamide / tetrahydrofuran = 90 / Using 10 things,
Joined and held for 20 minutes.

Example 4 A mixed solution of dimethylformamide and tetrahydrofuran was used as a welding agent in the open portion 18 of the split boot 1 made of a polyurethane thermoplastic elastomer material, and the mixing ratio was dimethylformamide / tetrahydrofuran = 50 / 50, and a polyurethane-based thermoplastic elastomer material was mixed to adjust the viscosity to 500 mPa · s.
Hold for minutes.

Example 5 A mixed solution of dimethylformamide and tetrahydrofuran was used as a welding agent in the open portion 18 of the split boot 1 made of a polyester thermoplastic elastomer material, and the mixing ratio was dimethylformamide / tetrahydrofuran = 50 / 50, a polyester-based thermoplastic elastomer material was mixed, and the viscosity was adjusted to 500 mPa · s.
Hold for minutes.

<Comparative Example 1> Methanol was used alone as a welding agent in the open portion 18 of the split-type boot 1 made of a polyurethane-based thermoplastic elastomer material, and was joined and held for 20 minutes.

Comparative Example 2 Dimethylformamide was solely used as a welding agent and joined to the open portion 18 of the split-type boot 1 made of a polyurethane thermoplastic elastomer material.
Hold for 20 minutes.

<Comparative Example 3> Tetrahydrofuran was used alone as a welding agent in the open portion 18 of the split-type boot 1 made of a polyurethane-based thermoplastic elastomer material and joined.
Hold for 0 minutes.

Comparative Example 4 A mixed solution of dimethylformamide and tetrahydrofuran was used as a welding agent in the open portion 18 of the split boot 1 made of a polyurethane thermoplastic elastomer material, and the mixing ratio was dimethylformamide / tetrahydrofuran = 50 / 50, and further mixed with a polyurethane-based thermoplastic elastomer material to adjust the viscosity to 20,000 mPa · s, and joined,
Hold for 20 minutes.

The test results are as shown in the table of FIG. 19, which confirmed the effectiveness of the present invention.

When the opening 18 of the split boot 1 is joined by the joining method of the present invention, prior to this, the opening habit of the opening 18 is corrected and the opposing surfaces 18a, 18b are adjusted.
It is effective and effective to perform the welding after the force for separating the members does not act on the opening 18. The following method is used to correct the opening habit of the opening 18.

That is, first, after molding, the boot 1 is pressed from the outer periphery by a tightening means such as a rubber band, a wrapping cord, or a wrapping cloth and put into a constant temperature bath (in the case of a urethane type, 90 boots).
For 1 hour). Alternatively, immediately after molding, the boot 1 is pressed from the outer periphery by a tightening means such as a rubber band and deformed by preheating (preheating) (5 hours at room temperature). Alternatively, after molding, the boot 1 is pressed from the outer periphery by a tightening means such as a rubber band, and locally deformed by applying heat to the side opposite to the opening.

In the split type boot 1 according to the first embodiment, the small diameter side mounting portion 11 and the large diameter side mounting portion 1 are provided.
A packing made of grommets 2 and 3 such as NBR is arranged on the inner peripheral side of 2, and the packing seals between the mounting portions 11 and 12 and the shaft or outer race of the universal joint. In one or both of the attachment portion 11 and the large-diameter attachment portion 12, instead of or in combination with the packing, the attachment portions 11, 12 are used.
A required number of lip portions may be integrally formed on the inner peripheral surface of the device, and a necessary sealing action may be secured by the lip portions. An example will be described below.

That is, in the split-type boot 1 shown in FIGS. 20 and 21, the small-diameter-side mounting portion 11 is provided between the shaft 52 by the packing 51 made of a grommet such as NBR disposed on the inner peripheral side. Although the sealing property is ensured, the large-diameter side mounting portion 12 has no packing, and an annular lip portion 53 is provided on the inner peripheral side of the mounting portion 12 as shown in FIG.
The required number of pieces are integrally formed, and the necessary sealing properties are secured by the lip portion 53 being in close contact with the outer peripheral surface of the outer race 54. In the figure, three lip portions 53 are arranged at predetermined intervals in the axial direction, and lip portions 53a and 53c on both sides in the axial direction are each formed into a rectangular cross section, and a lip 53b at the center in the axial direction. Are formed in a triangular cross section.

Since the boot 1 is provided with an open portion which is open at one location on the circumference, the mounting portion 12 is also divided at one location on the circumference, and accordingly, each lip portion 53 and its connecting base are connected. 55 is also divided at one location on the circumference. Regarding this divided structure, the divided end faces (also referred to as opposing faces) 12A and 12B of the mounting portion 12, the respective lips 53 and the divided end faces 53A and 53B of the connection base 55 thereof, Are displaced in the circumferential direction at one and the other of the male and female structures in a step-like manner.
Since the entire bonding area increases, the bonding force can be increased.

If the joining force is insufficient, the grease in the boot 1 may enter between the lip portions 53b and 53c, or the grease entering between the lip portions 53b and 53c may enter between the lip portions 53b and 53c. It is feared that the boot 1 may be twisted due to this in the circumferential direction. To solve this, it is effective to further increase the joint area as described below.

That is, as shown in FIG.
A protrusion or end wall-shaped step portion 56A that expands in the radial direction of the boot 1 is integrally formed on one of the divided end surfaces 12B, and the protrusion or end wall-shaped step portion 56A is formed on the other divided end surface 12A. Notch-shaped or end-faced step portions 5 on the receiving side, which are inserted alternately in the axial direction and are closely contacted in the axial direction.
6B, and the divided end faces 12A, 12B, 53A, 53B
22 are joined together by joining the stepped portions 56A and 56B together at the axial end surfaces, thereby increasing the joint area as compared with the case of FIG. In this way, the joining force is further increased by further increasing the joining area, so that even if a torsional load is applied to the boot 1, the boot 1 can be prevented from being twisted. Step 5
6A and 56B each have a lip 53
It is the same as the inner diameter of (53a). Note that, in this embodiment, all other configurations such as the material and the joining structure of the boot 1 are the same as those in the first embodiment.

[0110]

The present invention has the following effects.

That is, first, regarding the first aspect, the divided ends of the boots are integrally joined together when the ridges and the recesses are engaged with each other by engagement, and a large joint area is secured by the overlapping ridges. Therefore, the bonding strength is high and the sealing performance is excellent. In addition, since the ridge is shaped to be engaged with the ridge on one side in the thickness direction, the divided ends can be made relatively thin, so that the responsiveness when repeatedly subjected to bending and stretching deformation is good, and Fatigue durability is also improved. Further, when the mounting portions at both ends in the axial direction of the boot are mounted on the outer peripheral surface of a mating member such as a universal joint via a packing, the sealing performance at the mounting portion can be improved.

According to the second and third aspects of the present invention, since the thickness of the divided end portion at the valley portion of the bellows portion of the boot is reduced, stress is less likely to be concentrated at the valley portion. The generation of cracks can be effectively prevented, and the stress at the valleys can be reduced, the fatigue property can be improved, and the life can be extended.

Further, in the case of claim 4 and the following, when manufacturing the boot, the troublesome work of correctly attaching the fastener to the facing surface of the open portion can be omitted, so that the manufacturing of the boot is facilitated. Can be. In addition, when the boot is mounted, it is only necessary to attach a heating element to the outer surface of the opening and generate heat from the heating element, so that a person can leave the work site during the welding operation. Therefore, the joining operation of the open portion of the boot or the mounting operation of the boot can be facilitated. When the material of the boot is a polyurethane-based thermoplastic elastomer, the welding can be completed in a short time because the bonding property by welding is excellent. In addition, if the heating element is given a deformability that follows the bellows using a bag with irregular shape, or if the heating element is previously formed with irregularities, the heating element can be used only with the convex part of the bellows. Therefore, the temperature can be increased evenly because it is in close contact with the recess. Therefore, the welding time can be shortened also from this point. Further, the open portions welded and joined have excellent sealing properties because the opposing surfaces are integrated by welding. Therefore, the operation of separately applying a coating agent, a sealant, or the like to the opposing surface can be omitted, and the joining operation of the open portion or the operation of mounting the boot can be facilitated also from this point. Furthermore, since the welded open part is freely deformed following the deformation of the bellows part, the boot is also excellent in the deformation followability of the open part. This prevents the opening from being damaged in a short time,
Its durability can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a split-type boot according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is an enlarged sectional view of a main part of the split type boot,
(A) is a sectional view of an unjoined state, and (B) is a sectional view of a joined state.

FIG. 4 is a cross-sectional view of a main part of a split-type boot showing another example of a ridge and a ridge.

FIG. 5 is a sectional view of a split-type boot according to a second embodiment of the present invention.

FIG. 6 is an enlarged sectional view of a main part of the split type boot,
5A is an enlarged sectional view taken along line AA in FIG. 5, and FIG. 5B is an enlarged sectional view taken along line BB in FIG.

7A and 7B are cross-sectional views of a main part of a split-type boot according to a third embodiment of the present invention, wherein FIG. 7A is a cross-sectional view of a state where the boot is cut at a peak or a slope of a bellows, and FIG. Section view of the state cut by

FIG. 8 is a sectional view of a split-type boot according to a fourth embodiment of the present invention.

FIG. 9 is an enlarged sectional view of a main part of the split type boot,
8A is an enlarged cross-sectional view taken along line CC in FIG. 8, and FIG. 8B is an enlarged cross-sectional view taken along line DD in FIG.

FIG. 10 is a perspective view of a split-type boot according to a fifth embodiment of the present invention.

FIG. 11 is a perspective view of a heating element according to the embodiment of the present invention.

FIG. 12 is an explanatory view of a state in which a heating body is fixed to a split-type boot.

FIG. 13 is an explanatory view showing a state in which the heating element is fixed to the split-type boot.

FIG. 14A is a perspective view showing another example of the heating body,
(B) is a perspective view of a state where the heating body is folded.

FIG. 15 is a perspective view showing another example of the heating element.

FIG. 16 is a perspective view showing another example of the heating element.

FIG. 17 is a perspective view showing another example of the heating element.

FIG. 18 is a table showing performance test results of a welded structure.

FIG. 19 is a table showing the performance test results of the welding agent.

FIG. 20 is a cross-sectional view of a split boot according to another embodiment of the present invention.

FIG. 21 is a half cut sectional view showing a mounted state of the boot.

22 (A) and 22 (B) are perspective views showing a joining structure and a sealing structure of a large-diameter end portion of the boot.

FIGS. 23A and 23B are perspective views showing another joining structure and a sealing structure of the large-diameter end portion of the boot in both FIGS.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Split-type boot 11,12 Attachment part 11a, 12a Band attachment groove 12A, 12B, 53A, 53B Divided end face 13 Bellows part 13a Crest part 13b Valley part 14,15 Divided end part 14a, 15a End face 14b Inner peripheral surface 16 Convex stripe 161 Neck 161a Outer peripheral surface 162 Head 162a, 172a Engagement step 162b Outer peripheral taper surface 162c Tip 17 concave ridge 171 Neck receiving portion 171a Outer diameter surface 172 Head receiving portion 172b Inward tapered surface 173 Overlapping convex end 173a End Parts 18a, 18b Opposing surfaces 2, 3 Grommets (packing) 21 Belt-shaped fitting grooves 22, 32 Sealing ridges 31 Fitting step portions 41 Heating body 42 Bag 43 Sticking surface 44 Heating surface 45 Uneven shape 46 Knotting 47 Stretchable cloth 48 Magic tape 51 Packing 52 Shaft 53, 53a, 53b, 53 Lip 54 outer race 55 connecting base 56A, 56B stepped portion

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hiromitsu Yamoto 4-3-1 Tsujido Shinmachi, Fujisawa-shi, Kanagawa N OK Co., Ltd. (72) Inventor Yukihisa Tateishi 4-3-1 Tsujido Shinmachi, Fujisawa-shi, Kanagawa N OK Co., Ltd. (72) Kenichi Fujimoto, Inventor 4-3-1 Tsujido Shinmachi, Fujisawa-shi, Kanagawa NOK Co., Ltd. (72) Inventor Kazuhiko Fujimoto 4-3-1 Tsujido Shinmachi, Fujisawa-shi, Kanagawa NOK Co., Ltd. (72) Inventor Atsushi Nagashima 4-3-1 Tsujido Shinmachi, Fujisawa-shi, Kanagawa N OK Co., Ltd. (72) Inventor Junichi Nakayama 4-3-1 Tsujido Shinmachi, Fujisawa-shi, Kanagawa F-term in NOK Co., Ltd. 3J043 AA03 FA06 FA07 FB04

Claims (11)

[Claims] 1. A cylindrical boot (1) having a circumferentially divided one portion, wherein said boots (1) are divided into end portions (14, 15) which face each other in the circumferential direction and are integrally joined to each other when mounted. A convex ridge (16) and a concave ridge (17) extending along the axial cross-sectional shape of the boot (1) are formed, and the convex ridge (16) on the one divided end (14) side and the other divided end ( The concave ridge (17) on the 15) side has a shape that is engaged with each other on one side in the thickness direction, and the convex ridge (16) is on the non-engaging side of the concave ridge (17).
An overlapped ridge (173), which is longer and protrudes and is joined over the ridge (16) and the one split end (14).
A split-type boot characterized in that a boot is formed. 2. The split-type boot according to claim 1, wherein the end (173a) of the overlapping ridge (173a) in the valley (13b) of the bellows (13) of the boot (1) is the other split end. A split-type boot formed at the same position in the circumferential direction as the end face (15a) of the portion (15), or formed so as to retreat in the circumferential direction from the end face (15a). 3. A cylindrical boot (1) having a circumferentially divided one portion, wherein said boots (1) are divided into end portions (14, 15) which are circumferentially opposed to each other and are integrally joined to each other when mounted. A convex ridge (16) and a concave ridge (17) extending along the axial cross-sectional shape of the boot (1) are formed, and the convex ridge (16) on the one divided end (14) side and the other divided end ( The recess (17) on the 15) side has a shape that is engaged with each other on one side in the thickness direction, and is a non-engagement side of the recess (17) and a crest on the bellows portion (13) of the boot (1). (13a) and a slope (1) connecting the peak (13a) and the valley (13b).
3c), the overlapped ridge (173), which is longer than the ridge (16) and is joined to the ridge (16) and the one divided end (14), is formed. Split-type boots featured. 4. An open portion (1) obtained by dividing one portion on the circumference.
8), which is a split-type boot (1) that is mounted by covering the mounting member such as a universal joint and then joining the open portion (18), wherein the open portion (18) is self-heating. A split type boot characterized in that it is joined by welding while being heated by a heating body (41) provided with: 5. An open portion (1) obtained by dividing one portion on the circumference.
8), which is a method of joining a split-type boot (1) to be attached by covering an attachment member such as a universal joint and then joining the open portion (18). A method for joining split-type boots, comprising bringing a heating body (41) having heat generation properties into contact or close proximity, and welding while heating the opening (18) with the heating body (41). 6. An open portion (1) obtained by dividing one portion on the circumference.
8) a welding agent used when joining the split-type boot (1) to be attached by covering the attachment member such as a universal joint and then joining the open portion (18); Opposing surfaces (18a) (18b) of the opening (18)
A welding agent which is applied to the surface and welds the opposed surfaces (18a) and (18b). 7. The welding agent according to claim 6, wherein the welding agent comprises a solvent that dissolves the thermoplastic elastomer. 8. The welding agent according to claim 6, wherein the welding agent is a solvent of dimethylformamide, tetrahydrofuran, toluene, ethyl acetate, methyl ethyl ketone, acetone, cyclohexanone, or dichloromethane, alone or in combination. Agent. 9. An open part (1) obtained by dividing one portion on the circumference.
8), a heating element (41) used when joining the split-type boot (1) attached by covering the attachment member such as a universal joint and then joining the opening (18).
And has self-heating properties, is fixed to the boot (1), and comes into contact with or close to the opening (18).
8) A heating element characterized in that the heating element is heated and welded. 10. A heating element according to claim 9, wherein said heating element (41) is provided with a heat-generating component in a bag (42) having an irregular shape such that said heating element (41) deforms following the bellows shape of the boot (1). A heating element characterized by being housed. 11. The heating element (41) according to claim 9, wherein the heating element (41) is in close contact with the opening (18) along the bellows shape of the boot (1).
(45) on the outer surface of the bellows in advance along the bellows
Is a shaped body.