JP3476004B2 - Split type boot, joining method thereof and heating body - Google Patents

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 particularly to a universal joint having a circumferentially divided shape. Etc. related to those that can be mounted from the side.

[0002]

2. Description of the Related Art In this type of boot, the bellows-like flexible portion of the boot flexibly expands and contracts by attaching the mounting portions at both axial ends thereof to, for example, the outer race and joint shaft of a universal joint. At the same time, foreign matter from the outside is prevented from entering the operating portion of the universal joint, and grease or the like filled in the operating portion is sealed.

One of the above boots is of a split type.
A split boot according to the related art is a rubber boot divided in a part in a circumferential direction thereof, and a plurality of male couplings arranged at predetermined intervals at split ends facing each other in the circumferential direction. A fastener including a member and a female coupling member is integrally provided. That is, at the time of mounting, the split ends are opened to cover the universal joint or the like from the side, and the fasteners are combined and bonded with an adhesive so that the split ends are bonded to each other in close contact with each other. It has become.

[0004]

The boot is rotated by rotating the outer race having the mounting portions at both ends in the axial direction fixed thereto and the axis of the joint shaft inclining to each other.
The bellows section repeats bending and stretching operations every half cycle of rotation. Then, in the split-type boot, when the split ends bonded to each other are repeatedly bent and stretched, the cured adhesive layer may be deteriorated due to fatigue such as cracks, and grease in the universal joint may leak early. Is pointed out. Further, it is necessary to provide the male coupling member and the female coupling member of the fastener with high precision at the divided ends, and since this fastener has a low sealing property, it is necessary to secure the sealing property by applying a coating agent or the like. Moreover, it is pointed out that the boot may be damaged in a short period of time due to its poor followability to bending and stretching deformation.

The present invention has been made under the above circumstances, and its main technical problem is to improve the sealing performance and the fatigue strength at the split ends of the split boot. It is to improve workability when mounted.

[0006]

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

That is, first, the split-type boot according to claim 1 of the present invention is a boot in the shape of a cylinder divided at one position in the circumferential direction, and the boots are opposed to each other in the circumferential direction and are integrally joined to each other when mounted. A convex strip and a concave strip extending along the axial cross-sectional shape of the boot are formed at the end portions, respectively, and the convex strip on one split end side and the concave strip on the other split end side are mutually formed on one side in the thickness direction. A overlapping projection is formed which has a shape to be engaged, and which protrudes longer than the projection on the non-engagement side of the recess and is joined across the projection and the one split end, and the split end is formed. Is to apply a welding agent, insert the ridges and ridges into each other, engage them, and heat them with a heating element.
Are further joined to each other, and the overlapping protrusions are
It is characterized in that the convex line is guided toward the concave line at the time of matching. Further, in this configuration, more preferably, the mounting portions at both axial ends of the boot are
The boot is mounted on the outer peripheral surface of the mating member through a packing made of a rubber-like elastic material having elasticity higher than that of the boot and divided at one position in the circumferential direction.

According to a second aspect of the present invention, there is provided the split type boot according to the first aspect, wherein the end portion of the overlapped ridge in the valley of the bellows portion of the boot is the other split end portion. It is characterized in that it is formed in the same direction as the end face of the above, or is receded in the circumferential direction from this end face.

[0009]

[0010]

According to a third aspect of the present invention, there is provided a method of joining split boots, comprising an open portion formed by dividing one portion on a circumference, covering a mounting member such as a universal joint, and then joining the open portion. A method of joining split boots to be mounted by means of applying a welding agent to the facing surface of the open part when mounting the boot on the outer periphery of a mounting member such as a universal joint ,
In front of the heating element that contains the exothermic component and is self-heating
The opening portion is brought into contact with or close to the opening portion, and the opening portion is welded while being heated by the heating body.

[0012]

[0013]

[0014]

A heating element according to claim 4 of the present invention is
A heating element that has an open portion that is divided at one location on the circumference and that is used when joining a split-type boot that is attached by covering a mounting member such as a universal joint and then joining the open portion. The bag has a self-heating property by containing a heat-generating component, and is fixed to the boot so as to be in contact with or close to the open portion and heat-weld the open portion.

A heating element according to claim 5 of the present invention is
The heating element according to claim 4 is characterized in that the heating element contains an exothermic component in a bag having an irregular shape so that the heating element is deformed following the bellows shape of the boot.

Furthermore, the heating body according to claim 6 of the present invention is the heating body according to claim 4 described above, wherein the heating body is in close contact with the open portion along the bellows shape of the boot. It is characterized in that the outer surface is formed in advance with a concavo-convex shape that conforms to the concavo-convex shape of the bellows.

According to the split-type boot according to the first aspect of the present invention having the above-described structure, the split portions of the boot joined to each other in the mounting state to the mounting member such as the universal joint ensure a good sealing property. . This is because the ridges and the ridges are continuously extended to the divided ends of the boot, and their mating surfaces are integrated by welding.
In addition, a large joint area is ensured 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-engaging side of the concave ridge. .

Further, since the convex strip has a shape to be engaged with the concave strip on one side in the thickness direction, the divided end portions are made thinner than in the case where the engaging portions are formed on both sides in the thickness direction. You can For this reason, the insertion resistance at the time of temporarily joining the divided end portions by inserting and engaging the convex strip into the concave strip is reduced, and the overlapping convex strip serves as a guide at the time of insertion, so that the temporary joining work is performed. Can be easily performed, and the increase in stress due to repeated bending and stretching deformation can be suppressed, so that fatigue durability is improved.

Further, when the mounting portions at both axial ends of the boot are mounted on the outer peripheral surface of a mating member such as a universal joint through a packing formed of a rubber-like elastic material having a higher elasticity than the boot, the mounting is performed. The sealability of the portion can be improved.

It should be noted that if the polymerized ridge in the boot according to the above-mentioned claim 1 is provided over the entire length of the bellows part of the boot, there is a tendency that the wall thickness of the joint portion becomes thicker. Since the stress on the outer surface of the valley portion of the bellows portion is large, there is a concern that an early crack may occur here. Therefore, in such a case, as in the boot according to claim 2 of the present invention, the end of the overlapping ridge in the valley of the bellows part of the boot is circumferentially located at the same position as the end face of the other divided end, or It is preferable to form it so as to recede in the circumferential direction from this end face, and if this is done, the wall thickness of the joint portion in the valley portion is reduced,
It is possible to reduce the generated stress. In addition, the non-engagement side of the concave line , the peak of the bellows part, and the slope part connecting the peak and the valley, project longer than the convex line, and the convex line and one of the divided ends. Even if the polymerized ridges are formed so as to be joined across the portions, the same effect can be obtained.

[0022]

In the boot joining method according to the third aspect of the present invention, the boot is manufactured without attaching the fastener to the facing surface of the open portion, and the boot is attached to the outer periphery of the attaching member such as the universal joint. At this time, a welding agent is applied to the facing surfaces of the open portion to weld the facing surfaces to each other. In addition, when welding the open portion in this way, a heating body having self-heating property is brought into contact with or close to the open portion, and the open portion is heated by this heating body to perform the welding, thereby promoting the welding reaction or the bonding reaction. Let The open portion joined by welding is excellent in sealing property because the opposing surfaces are integrated with each other, and can be freely deformed following the deformation of the bellows portion. As a heating element with self-heating property, iron powder,
It is preferable to use water, activated carbon and salt or metal oxides and water as main components which generate heat mainly due to an oxidation reaction or a reduction reaction. If anything, it is possible to use it. Having self-heating ability means
When it is used, it produces heat by itself,
It means that energy supply such as electric power is not required. Melting
In order to ensure excellent bonding by wearing,
It is preferable to use thermoplastic elastomer as the material, and especially
In order to fully exhibit the performance as boots, high strength
Polyurethane elastomer with excellent durability
Mer or polyester thermoplastic elastomer
Is preferred.

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, iron powder, water, activated carbon and salt or metal oxide and water. Which contains a heat-generating component whose main component is, and when the outer bag in the form of a shielding film that encloses this heating element is opened, the moisture in the air comes into contact with 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 and weld the open portion. In addition, even though the outer surface of the boot has irregularities (mountains and valleys) due to the bellows, the heating element transfers this heat to the open section so that the heat generating component is transferred to the bag having an irregular shape. It is preferable that the heating element is accommodated in the heating element or that the outer surface of the heating element is preliminarily formed with a concavo-convex shape that conforms to the irregularities of the bellows, and the heating element is brought into close contact with the entire outer surface of the opening. As a result, the heating element comes into close contact with or approaches not only the convex portion (mountain portion) of the bellows but also the concave portion (valley portion), and the temperature of the concave portion rises without much changing the temperature of the convex portion. It is possible to raise the overall temperature as a whole, and as a result, it is possible to shorten the welding time.

Further, for example, if a dryer for blowing hot air is used to heat the open part, a person must carry the work with the dryer until the welded part is sufficiently dried, and further In order to prevent the opening from opening in the middle, a restraint must be additionally provided to keep the opening closed. In addition, when the hot air is blown by the dryer, there is a possibility that a great variation occurs in the temperature between the portion where the hot air is blown and the 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 part of the boot for welding, it is possible to proceed with the work without the need of a person during the drying process, and a separate restraint means is not required. Also, the open portion can be maintained in the closed state until the welded portion is dried, and the heating temperature can be easily kept constant. In addition, external heat energy sources such as power supply equipment and exothermic lights are not required. As a method of fixing the heating element to the outer surface of the open part of the boot, an adhesive sheet,
It is preferable to use an attachment means such as an adhesive tape, a knot, an elastic cloth or a velcro tape.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION First Embodiment FIG. 1 to FIG. 3 show a preferred embodiment of a split boot according to the present invention. First, in FIG. 1, reference numeral 1 is a boot entirely made of a thermoplastic elastomer.

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

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

The boot 1 has a small-diameter mounting portion 11 formed at one axial end, a large-diameter mounting portion 12 formed at the other axial end, and a circumferential direction between these mounting portions 11, 12. Has a thin bellows portion 13 in which a mountain portion 13a and a valley portion 13b are repeatedly formed. The mounting parts 11, 1
Band mounting grooves 11a and 12a that extend in the circumferential direction are formed on the outer peripheral surface of 2, and the mounting portions 11 and 12 are provided in the band mounting grooves 11a and 12a, for example, a joint shaft and an outer joint of a universal joint. A band for tightly binding to the outer peripheral surface of the race is wound.

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

A convex strip 16 is formed on one of the split ends 14 of the boot 1 so as to project in a direction opposite to the other split end 15, and the other split end 15 has the convex strip 16 and Corresponding groove-shaped recesses 17 are formed. These ridges 16
The concave line 17 extends along the entire cross section of the boot 1 along the entire axial length of the bellows portion 13.

As shown in FIG. 3, the ridge 16 is used for the boot 1
Of the end portion 14a of one of the divided ends 14 of the neck portion 161 protruding from a position unevenly distributed on the inner periphery of the end surface 14a, and a head portion 162 formed at the tip of the neck portion 161. The head portion 162 has an outer peripheral surface 161a. Has an engaging step portion 162a that rises to the outer peripheral side, and an outer peripheral taper surface 162b that has a smaller diameter from the outer peripheral edge of the engaging step portion 162a toward the tip 162c. The inner peripheral surface 16a of the ridge 16 constitutes a flat surface which is continuous with the inner peripheral surface 14b of the one divided end portion 14.

The concave line 17 has a sectional shape corresponding to that of the above-mentioned convex line 16, that is, the end face 1 of the other divided end 15 facing the one divided end 14 side.
The neck receiving portion 171 extending from 5a and the head receiving portion 172 formed in the back of the neck receiving portion 171 are extended.
Reference numeral 72 denotes an engaging step part 172a rising from the outer diameter surface 171a of the neck receiving part 171 to the outer peripheral side, and the engaging step part 1
The outer diameter 72a has an outer diameter taper surface 172b having a smaller diameter toward the inside of the divided end portion 14. Also,
The inner peripheral side of the recessed ridge 17 extends toward the side of the one divided end portion 14 longer than the protruding length of the ridge 16, and the overlapped ridge 1 extends.
73, the outer peripheral surface 173a of which is the ridge 16
Inner peripheral surface 16a and one divided end portion 1 continuous with the inner peripheral surface 16a
4 is formed corresponding to the inner peripheral surface 14b.

The ridge 16 is on one side (outer peripheral side) in its thickness direction.
Since the engaging stepped portion 172a is formed only on the ridges 17 and the concave ridges 17 have a shape corresponding to this, as shown in FIG.
Compared with the case where the engaging step portions a and b are formed on both the outer circumference and the inner circumference of the 6'and the concave strip 17 ', the divided end portion 1
The wall thickness t of 4, 15 can be reduced.

As shown in FIG. 1, grommets 2 and 3 as packings are arranged on the inner circumferences of the mounting portions 11 and 12 at both axial ends of the boot 1, respectively. The grommets 2 and 3 are more elastic than the thermoplastic elastomer forming the boot 1 and have excellent oil resistance, cold resistance and compression set, for example NBR (nitrile rubber).
It is formed of a rubber material such as, and like the boot 1, at least one location in the circumferential direction is divided.

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 the outer peripheral surface thereof.
A band-shaped fitting groove 21 that can be fitted to the inner peripheral portion of the above is formed, and a sealing projection 22 continuous in the circumferential direction is formed on the inner peripheral surface. Similarly, the grommet 3 arranged on the inner periphery of the mounting portion 12 on the large diameter side of the boot 1 has the mounting portion 12 on the outer peripheral surface thereof.
A fitting step portion 31 that can be fitted to the inner peripheral portion of is formed, and a seal ridge 32 that is continuous in the circumferential direction is formed on the inner peripheral surface.

As described above, the split boot having the above structure is mounted as, for example, a sealing means for a universal joint (not shown). At the time of this mounting, the split portion of the boot 1 is opened, and the mounting portion 11 on the small diameter side is on the joint shaft side of the universal joint, and the mounting portion 12 on the large diameter side is on the outer race side. 3A, the convex strip 16 of the one split end portion 14 and the concave strip 17 of the other split end portion 15 are inserted and fitted from the separated state shown in FIG. 3A as shown in FIG. 3B. By doing so, the divided end portions 14 and 15 are temporarily joined together.

In the above-mentioned temporary joining process, the ridges 16 are the recesses 1
It is guided by the overlapping ridges 173 that project long from the inner circumference of 7 toward the divided end portion 14 side. Then, when the head 162 of the ridge 16 is inserted into the neck receiving portion 171 of the groove 17, the groove 17 is deformed so as to be opened once due to the interference with the outer peripheral tapered surface 162b of the head 162. When the head 162 is completely inserted into the head receiving portion 172 of the recessed line 17, the convex line 16 and the recessed line 17 are in close contact with each other as shown in FIG. 3 (B). . As shown in FIG. 2, the boot 1 made of a thermoplastic elastomer is formed in a shape in which the divided portions are opened to some extent, and therefore the boot 1 tries to open due to the elasticity of the thermoplastic elastomer, but as shown in FIG. In the state shown, since the engagement step portions 162a and 172a are engaged with each other, the temporary connection state is maintained.

The grommet 2 is arranged on the outer peripheral surface of the joint shaft of the universal joint so as to hug it from the side, and the boot 1
The mounting portion 11 on the small diameter side of the metal band is arranged such that the inner peripheral portion thereof is fitted into the band-shaped fitting groove 21 formed on the outer peripheral surface of the grommet 2 and is wound around the band mounting groove 11a. Tied up by. Similarly, the grommet 3 is arranged on the outer circumferential surface of the outer joint 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 the inner circumferential portion on the outer circumferential surface of the grommet 3. It is arranged so as to be fitted to the formed fitting step 31 and is tightly bound 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 grommets 2 and 3 made of nitrile rubber or the like which is well-adapted to the mating material and is rich in elasticity.
It is fixed to the outer peripheral surface of the joint shaft and the outer peripheral surface of the outer race of the universal joint via. In particular, the mounting parts 11, 1
2 and the grommet 2 and 3 are closely contacted in a concavo-convex fitting state by the tight binding force of the metal band from the outer periphery, and the outer peripheral surface of the joint shaft and the outer peripheral surface of the outer race in the sealing protrusions 11b and 12b of the grommet 2 and 3. A good sealing state can be obtained by locally increasing the sealing surface pressure with respect to.

The divided end portions 14 and 15 temporarily joined by inserting and engaging the ridges 16 and the ridges 17,
For example, joining is performed by a method of welding using a welding agent. In this case, the welding agent may be used in advance as the divided end portions 14, 1
5 to the joint surfaces of each other, the joint surface of the convex stripes 16 and the concave stripes 17 and the superposed convex stripes 173, and spread them all over. As a result, the thermoplastic elastomers on the surface layer portion of the joint surface are temporarily melted and the welding agent evaporates to form a continuous thermoplastic elastomer structure, resulting in an integrally joined state.

When the boot 1 is formed of a polyether type polyurethane thermoplastic elastomer, the polyurethane thermoplastic elastomer is dimethylformamide as the welding agent used for joining the divided end portions 14 and 15. And Tetrahydrofuran (TH
The viscosity (mP) when dissolved in a solvent consisting of a mixture of F)
What is adjusted to 100 to 10,000 is preferable. That is, by adjusting the viscosity in this way, dripping is unlikely to occur when the solvent is applied, and workability can be improved. Further, as the solvent,
Ethyl acetate, acetone, methyl ethyl ketone (ME
It is also possible to use a mixed solvent prepared by adding a small amount of K), cyclohexanone, chloroform or the like to the dimethylformamide.

As a method of joining the divided end portions 14 and 15 temporarily joined by the convex strip 16 and the concave strip 17, it is possible to adopt the above-mentioned means such as welding with a welding agent or bonding with a fusion dope cement by heating. . Among them, in the joining by fusion, the divided end portions 14, 1
A method of temporarily heating the fitting portion of No. 5 or applying high frequency vibration is suitable. That is, the thermoplastic elastomers on the fitting surfaces of the divided end convex ridges 16 and the concave ridges 17 are temporarily heated and melted to form a continuous thermoplastic elastomer structure for joining.

By the above-mentioned work, the divided end portions 14 and 15 of the boot 1 are integrally joined to each other, and in particular, since the wide area of the joint is secured by the overlapping projection 173,
It is possible to effectively prevent the grease inside the universal joint from leaking out from the joint portion of the divided end portions 14 and 15 or from entering the muddy water and dust from the outside from the joint portion of the divided end portions 14 and 15. . The divided end portions 14 and 15 are formed thicker than the bellows portion 13. However, as described above, the divided end portions 14 and 15 are thinner and flexible than the mushroom-shaped engaging structure shown in FIG. It is possible to secure sufficient bending and deformability. Moreover, for this reason, the divided end portions 14 and 15 are
It is possible to improve fatigue endurance and prevent premature peeling of the joint surface.

Even if the divided end portions 14 and 15 are thinned in this way, the overlapping protrusions 17a are still provided over the entire length of the bellows portion 13 of the boot 1, so that the bellows portion 13 is When it is feared that a crack will occur in the valley 13b due to stress concentration, it is effective to take the following measures.

That is, first, as shown in FIG. 5 and FIG. 6, the end 173a of the overlapping ridge 173 in the valley 13b of the bellows 13 of the boot 1 is circumferentially aligned with the end surface 15a of the other divided end 15. It is formed so as to be flush with the position, so that the circumferential length of the overlapping ridge 173 in the valley 13b (see FIG.
(Refer to (B)) The mountain part 13a and this mountain part 13a and the valley part 13
It is made shorter than the circumferential length (see FIG. 6 (A)) of the overlapping projections 173 in the inclined surface portion 13c connecting with b, thereby substantially reducing the thickness of the divided end portions 14 and 15 in the valley portion 13b. (Second embodiment).

Alternatively, as shown in FIG. 7, the boot 1
The end 173a of the overlapped ridge 173 in the valley 13b of the bellows 13 is formed so as to recede in the circumferential direction from the end surface 15a of the other divided end 15, so that the overlap of the overlapped ridge 173 in the valley 13b is formed. Circumferential length (see Fig. 7 (B))
Are overlapped ridges 173 on the peaks 13a and the slopes 13c.
The length in the circumferential direction (see FIG. 7 (A)) is made shorter, whereby the thickness of the divided ends 14 and 15 in the valley 13b is substantially reduced (third embodiment).

Alternatively, as shown in FIGS. 8 and 9, the overlapping protrusions 173 are originally provided only on the peaks 13a and the slopes 13c of the bellows 13 of the boot 1 (see FIG. 9).
(See FIG. 9A), so that it is not provided in the valley 13b (see FIG. 9).
(See (B)), thereby substantially reducing the thickness of the divided end portions 14 and 15 in the valley portion 13b (fourth embodiment).

Therefore, the valley portion 1 is formed by these configurations.
By reducing the thickness of the divided end portions 14 and 15 in 3b, stress is less likely to be concentrated in the valley portion 13b, and thus cracking due to stress concentration can be effectively prevented, and stress in the valley portion 13b is reduced. It is possible to improve fatigue resistance and extend life.

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

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

Further, by forming the joint surface of the divided end portions 14, 15 and particularly the joint surface (the surface on the groove side) of the other divided end portion 15 into a rough surface, the wettability of the solvent is secured and the solvent is wetted. It is also possible to improve the holding property and improve the adhesiveness.

Further, returning to the description of FIGS. 1 to 3, the boot 1 is formed of a thermoplastic elastomer which is superior in strength, ozone resistance, fatigue resistance and water resistance as compared with a usual rubber material. Therefore, the grease is unlikely to leak due to fatigue damage of the joint portion, and exhibits excellent durability.

In the above embodiment, for example, the grommets 2 and 3 as the packing are the mounting portion 1 of the boot 1.
It is also possible to preliminarily incorporate the inner circumference of 1, 12 into the boot 1 by means such as fitting, or to integrate it with the boot 1 by adhesion or the like.

Regarding a concrete example of the embodiment,
A product durability test and a material water resistance test were performed together with the comparative example.

<Example> Polyoxymethylene glycol having a number average molecular weight of 1700: 660 parts and 1,4-butanediol: 55 parts as a chain extender were mixed to obtain 4,4 'as an organic diisocyanate corresponding to the theoretical amount. Diphenylmethane diisocyanate: 252.5 parts of diphenylmethane diisocyanate was added, and the resulting mixture was reacted at 160 ° C. for 10 minutes to obtain a thermoplastic polyurethane-type elastomer of a polyether type.
The split boot having the shape shown in FIG. 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-based thermoplastic elastomer of the same material as the joining object is dissolved in a solvent composed of dimethylformamide. Then, the one whose viscosity (mPa · s) was adjusted to 1000 was used. After applying the above-mentioned welding agent, it was kept stable for 15 minutes.

Comparative Example A thermoplastic polyolefin elastomer (Santoprene 101-87: manufactured by AES Co., Ltd.) was used to injection-mold a split boot having the shape shown in FIGS. Joining of the divided end portions 14 and 15 of the boot 1 was performed by welding with a welding agent, and dimethylformamide was used as the welding agent, and after the application of the welding agent, it was kept stable for 15 minutes.

Evaluation method 1. Product Durability Test The boots of Examples and Comparative Examples produced as described above were mounted on an oscillating rotation tester, and the durability time was measured. The durability time was judged by the time when grease leaked from the boot after the start of operation. [Test conditions] Temperature: Room temperature rocking angle: 25-40 ° Rocking 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 recognized 20 minutes after the start of the test, whereas in the example, it took 280 minutes until the occurrence of grease leakage. It was confirmed that the split-type boot molded from the polyurethane-based thermoplastic elastomer was more excellent in durability.

Even if a polyester type polyurethane thermoplastic elastomer is adopted as the material of the boot 1, the same effect as described above can be obtained. Further, in the illustrated embodiment, the convex strip 16 is provided with the concave strip 17 on the outer peripheral side.
However, it is also possible to have a shape in which the inner peripheral side is engaged with the concave line 17 and the overlapping convex line 173 is provided on the outer peripheral side of the concave line 17.

Fifth Embodiment As shown in FIG. 10, the split boot 1 according to the second embodiment has a tubular shape as a whole, and has an annular small-diameter side mounting portion (fixing portion) at one end opening. (Also referred to as “11”) and an annular large-diameter side mounting portion 12 having a larger diameter than the small-diameter side fixing portion 11 at the other end opening, and a bellows portion 13 is integrally molded between both mounting portions 11 and 12. However, the whole is molded with a thermoplastic elastomer. This thermoplastic elastomer is a polyurethane-based thermoplastic elastomer. The boot 1 also includes an open portion (also referred to as a joint portion or a cut portion) 18 that is open at one point on the circumference thereof over the entire length in a divided manner. The open portion 18 has a self-heating property. The heating element (also referred to as a heating agent, a heating element or an exothermic agent) is heated and welded to join.

The boot 1 is manufactured without attaching fasteners to the facing surfaces 18a and 18b of the open portion 18, and the open portion 18 is opened at the time of mounting to cover the boot 1 from the open portion 18 on the universal joint or the like. , Then open part 18
Are attached to the outer circumference of the universal joint by joining. At this time, the small diameter side mounting portion 11 is fixed to the drive shaft side by the band, and the large diameter side mounting portion 12 is also fixed to the universal joint side by the 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 metal oxides and water as main components is contained in a breathable bag 42 made of non-woven fabric or cloth. When an outer bag (not shown) made of a shielding film is opened during use, the moisture in the air comes into contact with iron, which causes an oxidation reaction, or a metal oxide and water cause a reduction reaction. . Therefore, high heat is generated 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 indefinite shape that is freely deformable, and one surface of the bag 42 is adhesive so that the heating body 41 can be fixed to the outer surface of the open portion 18 of the boot 1. A sticking surface 43 is formed by attaching a sheet or the like, and a heating surface 4 that emits high heat on the same surface 4
4 is set.

Although the above-mentioned heating uses the chemical reaction type heat generating material, a phase change type heat storage material which generates heat when the crystalline substance is crystallized from the supercooled state may be used. An example of the heat storage material is sodium acetate hydrate. It is more liquid than the former powdery substance, so it is easier to adapt to the shape of the boot.

As shown in FIGS. 12 and 13, the heating element 41 is formed on the outer surface of the open portion 18 of the boot 1 by the open portion 1.
It is attached so as to straddle 8, and the opening portion 18 is kept closed by the attachment force so that the opening portion 18 does not open during the welding work. In addition, unevenness (mountain valley) on the outer surface of the bellows part 4 of the boot 1
Since the bag 42 is appropriately deformed along with and adheres to the irregularities in a wide area, the heat generated in the heating body 41 is efficiently transmitted to the open portion 18. Therefore, the open portion 18 can be efficiently heat-welded by the high heat thus efficiently transmitted. Further, as shown in FIGS. 14 (A) and 15, an uneven shape 45 is formed in advance on the outer surface of the heating body 41,
Even if the uneven shape 45 is arranged in accordance with the unevenness of the outer surface of the bellows portion 4, the heat generating surface 44 of the heating body 41 can be brought into contact with the boot 1 in a wide area. 14
The heating element 41 of (A) is provided with a plurality of irregularities, and FIG.
The heating element 41 of 1 has one convex portion. Also, the heating element 4
When storing 1 in order to fold the outer surface into a concavo-convex shape as shown in FIG. 14 (B), the outer surface is made of a stretchable material such as nylon tights, nylon stockings, etc. It is preferable to pack it so that it can be shielded from moisture and the like.

As the mounting means for fixing the heating element 41 to the outer surface of the boot 1, various fixing means other than the above-mentioned adhesive sheet are conceivable, and FIGS. 16 and 17 show one example thereof. In the example of FIG. 16, as one of the heating elements, a plurality of knotting cords 46 are attached to both sides of a heating element 41 such as a commercially available body warmer. Connect each other. In addition, in the example of FIG. 17, a heating element 41 such as a commercially available warmer is also used.
A pair of elastic cloths 47 are attached to both sides of the elastic cloth 47, and a plurality of magic tapes 48 are attached to the elastic cloth 47. The elastic cloths 47 are wound around the outer periphery of the boot 1 and the magic tapes 48 are overlapped and closed. Therefore, in any case, the open portion 18 can be kept in the closed state in order to restrain the boot 1 from the outer periphery by the knot string 46 or the stretchable cloth 47, and the heating body 41 can follow the unevenness of the outer surface of the bellows portion 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 open portion 18. The cloth-made attachment means has a flat shape and covers the outer periphery of the boot 1, and thus has a heat retaining effect, and thereby has an effect of making the temperature of the welded portion uniform and promoting welding.

When the boot 1 is mounted on the outer periphery of a mounting member such as a universal joint, the universal joint or the like is first covered with the boot 1 as described above, and then the welding agent is applied to the facing surfaces 18a and 18b of the open portion 18. And then facing surface 1
8a and 18b are closed to close the open portion 18. Next, the above-mentioned various mounting means are used to maintain the closed state of the open portion 18 and bring the heating element 41 into close contact with the outer surface of the open portion 18 to generate heat. When the heating element 41 is removed from the boot 1 after waiting the required time, the heating element 41 is removed.
Due to the heat generation effect, the open portion 18 is heat-welded in a relatively short time, and the mounting work can be completed with this.

Therefore, according to this method, the boot 1
At the time of manufacturing, it is possible to omit the troublesome work that the fasteners have to be accurately attached to the facing surfaces 18a and 18b of the opening portion 18, and thus the manufacturing of the boot 1 can be facilitated first.

When the boot 1 is attached, the opening 1
Since it suffices to attach the heating body 41 to the outer surface of 8 and heat the heating body 41, a person can leave the work site during the welding work. Therefore, the opening 1 of the boot 1
It is possible to facilitate the joining work of 8 or the mounting work of the boot 1.

Further, the fusion-bonded open portion 18 is excellent in sealing property because the opposing surfaces 18a and 18b are integrated by fusion. Therefore, the facing surface 18
It is possible to omit the work of separately applying the coating agent or the sealant or the like to a and 18b, and also from this point, the work of joining the open portion 18 or the work of mounting the boot 1 can be facilitated.

Furthermore, since the welded open portion 18 freely deforms following the deformation of the bellows portion 4, the boot 1 is also excellent in deformability of the open portion 118. Therefore, it is possible to prevent the open portion 18 from being damaged in a short period of time and improve its durability.

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

The first of the performance tests is the joined open part 1
8 is a peeling test of No. 8 and the state when the joined open portion 18 is peeled off by hand is evaluated as follows. ◯: Not peeled off Δ: 50% of the open portion was peeled off ×: All of the open portion was peeled off

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 the joint and the open portion 18 is rotated 10 times at a maximum angle of 40 degrees. The condition is evaluated as follows. ◎: No opening ○: Very small (2 mm or less) 1 opening opening △: Very small (2 mm or less) opening opening ×: Several opening (2 mm or more) opening

Example 1 After the open part 18 of the split type boot 1 made of a thermoplastic polyurethane elastomer material was welded, the heating element 41 shown in FIG. 11 was applied to the open part 18 and held for 10 minutes.

Example 2 After the open part 18 of the split type boot 1 made of a thermoplastic polyurethane elastomer was welded, the heating element 41 shown in FIG. 14 was applied to the open part 18 and held for 10 minutes.

Example 3 After the open portion 18 of the split boot 1 made of a thermoplastic polyurethane elastomer was welded, the heating element 41 shown in FIG. 15 was applied to the open portion 18 and held for 10 minutes.

Example 4 After the open part 18 of the split type boot 1 made of a polyester thermoplastic elastomer material was welded, the heating element 41 shown in FIG. 11 was applied to the open part 18 and held for 10 minutes.

<Comparative Example 1> After the open portion 18 of the split boot 1 made of a polyurethane-based thermoplastic elastomer material is welded, the heating body 41 is opened.
It was held for 10 minutes without hitting 8.

<Comparative Example 2> After the open portion 18 of the split type boot 1 made of a polyurethane-based thermoplastic elastomer material is welded, the heating body 41 is opened.
It was held for 30 minutes without hitting No. 8.

<Comparative Example 3> After the open portion 18 of the split boot 1 made of a polyurethane-based thermoplastic elastomer material is welded, the heating element 41 is opened.
No 8 was applied and instead it was heated with a dryer for 10 minutes.

The test results are shown in the table of FIG. 18, and the effectiveness of the present invention could be confirmed by this.

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

That is, if the open portion 18 of the split boot 1 made of a thermoplastic elastomer is joined by adhesion or heat fusion with an adhesive instead of welding with a welding agent, the following problems may occur. It

That is, first, when the open portion 18 is adhered by the adhesive, the open portion 18 can be adhered but the adhesive cannot follow the movement of the boot 1. There is a risk that 18 will peel off. On the other hand, if the open portion 18 is welded by the welding agent as in the present invention, the joint portion and the boot body are integrated after the welding, so that the joint portion can follow the movement of the boot 1. Like

Further, there is no adhesive which is suitable for an assembling work in an actual maintenance factory or the like (it is desirable to complete the bonding work within 30 minutes). That is, in the instant adhesive type, the open portion 18 is lost before the bonding work is completed, and the open portion 18 cannot be bonded. In addition, with an ordinary adhesive (curing type), it takes about overnight to complete the adhesion, which is not suitable for work. On the other hand, if the open portion 18 is welded by the welding agent as in the present invention, the assembling work 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, one or a mixture of solvents such as dimethylformamide, tetrahydrofuran, toluene, ethyl acetate, methyl ethyl ketone, acetone, cyclohexanone and dichloromethane, and it dissolves a thermoplastic elastomer. To increase the viscosity of the solution. Further, the thermoplastic elastomer is dissolved in a mixed solution of dimethylformamide and tetrahydrofuran to have a viscosity of 10 to 10,000 mPas.
.S, and a mixed solution of dimethylformamide and tetrahydrofuran with a mixing ratio of dimethylformamide / tetrahydrofuran =
10/90 to 90/10, and further dissolve the thermoplastic elastomer in the solution to increase the viscosity to 10 to 1000.
It 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.

Further, when the open portion 18 is heated and fused, a fusing device (for example, a soldering iron, a dryer, a special device, etc.), a power source, etc. are required. There are some unfavorable aspects as the work of. On the other hand, if the open portion 18 is welded with a welding agent as in the present invention, these devices, power supplies, etc. can be eliminated.

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

The first of these performance tests is the joined open part 1
8 is a peeling test of No. 8 and the state when the joined open portion 18 is peeled off by hand is evaluated as follows. ◯: Not peeled off Δ: 50% of the open portion was peeled off ×: All of the open portion was peeled off

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 incorporated into the joint and the open portion 18 is rotated 10 times at a maximum angle of 40 degrees. The state is evaluated as follows. ◎: No opening ○: Very small (2 mm or less) 1 opening opening △: Very small (2 mm or less) opening opening ×: Several opening (2 mm or more) opening

The third of the performance tests is the evaluation of the easiness of the coating work, which shows the ease of controlling the coating amount when each welding agent is applied to the facing surfaces 18a and 18b of the open portion 18. It is evaluated as follows. ○: Very good △: Somewhat difficult to control, but there is no problem in work ×: Viscosity is too high or too low and 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-based thermoplastic elastomer material, and the mixing ratio was dimethylformamide / tetrahydrofuran = 10 /. 90 pieces were used, 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-based thermoplastic elastomer material, and the mixing ratio was dimethylformamide / tetrahydrofuran = 50 /. Fifty pieces were used, joined, and held for 20 minutes.

Example 3 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 thermoplastic polyurethane elastomer material, and the mixing ratio was dimethylformamide / tetrahydrofuran = 90 /. 10 pieces were used, joined and held for 20 minutes.

Example 4 A mixture of dimethylformamide and tetrahydrofuran was used as a welding agent in the open portion 18 of the split type boot 1 made of a thermoplastic polyurethane elastomer, and the mixture ratio was dimethylformamide / tetrahydrofuran = 50 /. It was 50, and a polyurethane-based thermoplastic elastomer material was further mixed to adjust the viscosity to 500 mPa · s, which was bonded and held for 20 minutes.

Example 5 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 polyester thermoplastic elastomer material, and the mixing ratio was dimethylformamide / tetrahydrofuran = 50 /. It was 50, and a polyester-based thermoplastic elastomer material was further mixed to adjust the viscosity to 500 mPa · s. The materials were bonded and held for 20 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, joined and held for 20 minutes.

Comparative Example 2 Dimethylformamide alone was used as a welding agent in the open portion 18 of the split-type boot 1 made of a polyurethane-based thermoplastic elastomer material, and bonded and held 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 the pieces were joined and held for 20 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 type boot 1 made of a thermoplastic polyurethane elastomer material, and the mixing ratio was dimethylformamide / tetrahydrofuran = 50 /. It was 50, and a polyurethane-based thermoplastic elastomer material was further mixed to adjust the viscosity to 20000 mPa · s.

The test results are shown in the table of FIG. 19, and the effectiveness of the present invention could be confirmed.

Further, when the open portion 18 of the split boot 1 is joined by the joining method of the present invention, the opening habit of the open portion 18 is corrected prior to this, and the facing surfaces 18a, 18b.
It is effective and easy to carry out the work that welding is performed after the force of the mutual separation is prevented from acting on the open portion 18. There are the following methods to correct the opening tendency of the opening portion 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 urethane type, 90).
1 hour at ℃). 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 (remaining heat) (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 heat is locally applied to the side opposite to the mouth opening to deform it.

In the split boot 1 according to the first embodiment, the small-diameter side mounting portion 11 and the large-diameter side mounting portion 1 are provided.
Packings made of grommets 2 and 3 such as NBR are arranged on the inner peripheral side of 2, respectively. The packing seals between the mounting portions 11 and 12 and the shaft of the universal joint or the outer race, but the small diameter side. Either one or both of the mounting portion 11 and the large-diameter side mounting portion 12 may be replaced with the packing or used in combination with the mounting portion 11, 12
It is also possible to integrally mold a required number of lip portions on the inner peripheral surface of and to secure the necessary sealing action 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 arranged between the shaft 52 and the shaft 52 by the packing 51 made of a grommet such as NBR arranged on the inner peripheral side thereof. Although the sealing performance is secured, 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 are integrally formed, and the lip portion 53 is in close contact with the outer peripheral surface of the outer race 54, so that the necessary sealing performance is secured. In the figure, three lip portions 53 are arranged at a predetermined interval in the axial direction, and lip portions 53a and 53c on both sides in the axial direction are each formed in a rectangular cross section, and a lip 53b at the center in the axial direction is formed. Has a triangular cross section.

Further, since the boot 1 is provided with an open portion which is open at one location on its circumference, the mounting portion 12 is also divided at one location on the circumference, and accordingly, each lip portion 53 and its connecting base portion. Although 55 is also divided at one place on the circumference, regarding this divided structure, the divided end faces (also referred to as facing faces) 12A and 12B of the mounting portion 12 and the divided end faces 53A and 53B of each lip 53 and the connecting base portion 55 thereof are divided. When one of the male and female structures is arranged so as to be displaced in the circumferential direction in a stepped manner, the mounting portion 12 including each lip 53 and its base 55 is arranged.
The joining force can be increased because the overall joining area is increased.

If this joining force is insufficient, the grease in the boot 1 may enter between the lip portions 53b and 53c, or the grease that enters between the lip portions 53b and 53c may be applied between the lip portions 53b and 53c. There is a concern that the boot 1 may be twisted in the circumferential direction and twisted due to this, but in order to eliminate this, it is effective to further increase the joint area as follows.

That is, as shown in FIG. 23, the mounting portion 1
A protrusion-shaped 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-shaped or end wall-shaped step portion 56A is formed on the other divided end surface 12A. Notch-like or end-face-like step portion 5 on the receiving side in which the plugs are inserted alternately in the axial direction and closely contact with each other in the axial direction.
6B is provided and divided end faces 12A, 12B, 53A, 53B
At the time of joining, the both step portions 56A and 56B are joined together at the end faces in the axial direction so that the joining area is increased as compared with the case of FIG. Then, since the joining force is further increased by further increasing the joining area, it is possible to prevent the boot 1 from being twisted even when a torsional load is applied to the boot 1. Step 5
6A and 56B respectively have the inner diameter dimension of the lip portion 53.
It is the same as the inner diameter of (53a). In this embodiment, the material of the boot 1, the bonding structure, and other configurations are the same as those in the first embodiment.

[0110]

The present invention has the following effects.

That is, first, according to claim 1, the divided ends of the boot are engaged and welded to each other by the projections and the recesses being engaged with each other, and since the large projection area is secured by the overlapping projections, the joining is ensured. It has high strength and excellent sealing property. In addition, since the divided end can be made relatively thin by forming the convex strip into a shape in which the convex strip is engaged with the concave strip on one side in the thickness direction, the responsiveness when subjected to repeated bending and stretching deformation is good, and Fatigue durability is also improved.
Further, when the mounting portions at both axial ends of the boot are mounted on the outer peripheral surface of the mating member such as the universal joint via the packing, the sealability of the mounting portions can be improved.

Further, according to claim 2 , since the thickness of the divided end portion in the valley portion of the bellows portion of the boot is thinned, stress is less likely to be concentrated in the valley portion, and thus cracks due to the stress concentration are not generated. It is possible to effectively prevent the occurrence, and it is possible to reduce the stress in the valley portion, improve the fatigue resistance, and extend the life.

Further, according to claim 3 or 4,
When mounting the tool, apply a welding agent to the facing surface of the open part,
Since it is only necessary to attach a heating element to the outer surface of the open portion and heat the heating element, a person can leave the work site during the welding work. Therefore, the work of joining the open portion of the boot or the work of mounting the boot can be facilitated.
When the boot material is a polyurethane-based thermoplastic elastomer, the welding can be completed in a short time because the joining property by welding is excellent. Claims
As shown in 5 or 6, by using a bag having an indefinite shape, the heating element is provided with deformability that follows the irregularities of the bellows, or if the heating element is pre-shaped to have an irregular shape, the heating element is The temperature can be evenly increased because the bellows closely contacts not only the convex portion but also the concave portion. Therefore, also from this point, the welding time can be shortened. Further, the fusion-bonded open portion has excellent sealing properties because the opposing surfaces are integrated by fusion. Therefore, it is possible to omit the work of separately applying the coating agent or the sealant to the facing surfaces, and also from this point, the work of joining the open portion or the work of mounting the boot can be facilitated. Furthermore,
Since the open portion welded and joined is freely deformed following the deformation of the bellows portion, the boot is also excellent in deformation followability of the open portion. Therefore, it is possible to prevent the open portion from being damaged in a short period of time and improve its durability.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a split 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 an essential part of the split boot,
(A) is a cross-sectional view of the unbonded state, (B) is a cross-sectional view of the completed bonding

FIG. 4 is a sectional view of a main part of a split-type boot showing another example of a convex stripe and a concave stripe.

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

FIG. 6 is an enlarged sectional view of an essential part of the split 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.

FIG. 7 is a cross-sectional view of a main part of a split-type boot according to a third embodiment of the present invention, in which (A) is a cross-sectional view in a state of being cut by a ridge or a slope portion of a bellows, and (B) is a valley portion. Cross-sectional view after cutting with

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

FIG. 9 is an enlarged sectional view of an essential part of the split boot,
8A is an enlarged sectional view taken along line CC of FIG. 8, and FIG. 8B is an enlarged sectional view taken along line DD of FIG.

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

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

FIG. 12 is an explanatory view showing a state where the heating element is fixed to the split boot.

FIG. 13 is an explanatory view of a state where the heating element is fixed to the split boot as well.

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

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

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

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

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

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

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

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

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

FIG. 23 (A) and FIG. 23 (B) are perspective views showing another joint structure and seal structure of the large-diameter side end portion of the boot.

[Explanation of symbols]

1 split boots 11,12 mounting part 11a, 12a band mounting groove 12A, 12B, 53A, 53B split end face 13 Bellows 13a Yamabe 13b Tanibe 14,15 split end 14a, 15a end faces 14b inner peripheral surface 16 convex 161 neck 161a outer peripheral surface 162 head 162a, 172a Engagement stepped portion 162b Tapered outer circumference 162c tip 17 concave 171 neck receiving part 171a outer diameter surface 172 Head receiving part 172b Inward taper surface 173 polymerized ridge 173a end 18 Open section 18a, 18b facing surfaces 2,3 Grommet (packing) 21 Belt-shaped fitting groove 22,32 Seal ridge 31 Fitting step 41 heating body 42 bags 43 Sticking surface 44 Heating surface 45 uneven shape 46 knot 47 elastic cloth 48 Velcro 51 packing 52 axis 53, 53a, 53b, 53c Lip part 54 outer race 55 Connection Base 56A, 56B stepped portion

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yukihisa Tateishi 4-3-1 Tsujido Shinmachi, Fujisawa City, Kanagawa NOK Co., Ltd. (72) Kenichi Fujimoto 4-3-1 Tsujido Shinmachi, Fujisawa City, Kanagawa Prefecture In Nuoka Co., Ltd. (72) Inventor Kazuhiko Fujimoto 4-3-1 Tsujido Shinmachi, Fujisawa City, Kanagawa Prefecture In Nu Co., Ltd. (72) Inventor Jun Nagashima 4-3-1 Tsujido Shinmachi, Fujisawa City, Kanagawa (72) Inventor Junichi Nakayama, 4-3-1 Tsujido Shinmachi, Fujisawa City, Kanagawa NOK Co., Ltd. (56) References JP-A-9-137864 (JP, A) JP-A-59-232820 (JP, A) JP-A-2-142975 (JP, A) JP-A-4-362377 (JP, A) JP-A-9-177972 (JP, A) JP-A-10-110821 (JP, A) 10-227359 (JP, A) JP 8-261324 (JP, A) JP 9-119522 (JP, A) Actually open 5-83532 (JP, U) Actually open 62-122925 (JP , U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16D 3/84 F16J 15/52

Claims (6)

(57) [Claims] 1. A tubular boot (1) divided at one circumferential position, said boots (1) being circumferentially opposed to each other at said divided ends (14, 15) integrally joined to each other when mounted. The ridges (16) and the ridges (17) extending along the axial cross-sectional shape of the boot (1) are formed, and the ridges (16) on one split end (14) side and the other split end ( The concave line (17) on the side of (15) has a shape in which it is engaged with each other on one side in the thickness direction, and the convex line (16) is provided on the non-engaging side of the concave line (17).
Overlapping ridges (173) that project longer and are joined across this ridge (16) and the one split end (14).
The divided ends (14, 15) are coated with a welding agent, and the ridges (16) and the ridges (17) are inserted into each other to be engaged with each other.
The heated ridges (173) are bonded to each other by heating with a heating element, and the overlapping ridges (173) are connected to each other during the insertion engagement.
Guiding the ridge (16) toward the ridge (17)
The split boot is characterized by: 2. The split boot according to claim 1, wherein the end (173a) of the overlapping ridge (173) in the valley (13b) of the bellows (13) of the boot (1) is the other split end. A split-type boot characterized in that it is formed so as to be located in the same direction as the end surface (15a) of the portion (15) in the circumferential direction or is receded in the circumferential direction from the end surface (15a). 3. An open portion (1
A method for joining split boots (1), comprising: 8), covering a mounting member such as a universal joint, and then joining the open portion (18). When it is mounted on the outer periphery of a mounting member such as the above, a self-heating property is obtained by applying a welding agent to the facing surfaces (18a) and (18b) of the open portion (18) and accommodating heat-generating components in the bag (42). The heating element (41) is brought into contact with or close to the opening (18), and the opening (18) is moved to the heating element (41).
A method for joining split boots, characterized in that the welding is carried out while heating. 4. An open part (1
8), a heating element (41) which is used when joining a split-type boot (1) which is equipped by covering a mounting member such as a universal joint and then joining the opening (18).
While the bag (42) contains a heat-generating component and has a self-heating property, the bag (42) is fixed to the boot (1) and comes into contact with or close to the opening (18) while heating the opening (18).
A heating element characterized by being welded . 5. The heating element according to claim 4 , wherein the heating element (41) is provided with an exothermic component in a bag (42) having an irregular shape so that the heating element (41) is deformed following the bellows shape of the boot (1). A heating body characterized by being housed. 6. The heating element according to claim 4 , wherein the heating element (41) is in close contact with the opening (18) along the bellows shape of the boot (1).
An uneven shape (45) along the unevenness of the bellows in advance on the outer surface of the
A heating element characterized by being shaped.