Multi-layered hose

Abstract: A multi-layered hose (10) according to the present invention comprises a rubber outer layer (20) and a resin or metal inner layer (22) which is integrally formed at the inner periphery surface of the rubber outer layer (20). The thickness of the resin inner layer (22) formed at the inner periphery surface of the edge portion (18) is thinner than that of the resin inner layer (22) formed at the inner periphery surface of a main portion (14) of the hose (10). Therefore, when a mating pipe (16) is inserted into the hose edge portion (18), the mating pipe (16) is satisfactorily adhered to the inner surface of the hose edge portion (18), thereby obtaining excellent sealing.

Description: The present invention relates to a multi-layered hose according to the preambles of claims 1 and 11 which is suitable for use as a filler hose for automobiles. Conventionally, a rubber material such as NBR·PVC rubber which shows oil resistance and oil penetration resistance is used as a filler hose (a fuel hose) for automobiles. However, the above filler hose comprising only rubber can't cope with recent severe regulations of oil penetration resistance. To solve the above problem, as shown in Figure 20, a thin and fluorine-contained rubber inner layer 102 is formed at the inner periphery surface of a rubber outer layer 100. The above hose having the fluorine-contained rubber inner layer 102 shows excellent efficiency, but the cost is high. So, it is not suitable for practical use. Concerning the conventional hose for transmitting refrigerant, as shown in Figures 20 and 21, it is usual that a thin resin inner layer 104 is laminated on the inner periphery surface of a rubber outer layer 100. When the above laminated structure is applied to a filler hose, the resin inner layer 104 having excellent oil resistance and excellent oil penetration resistance is laminated on the inner periphery surface of the rubber outer layer 100. Therefore, it is possible to easily obtain excellent oil resistance and excellent oil penetration resistance while maintaining flexibility which is required for the hose. Furthermore, it is possible to obtain an inexpensive hose. In this case, a hard resin material is usually used as the resin inner layer 104, and the resin inner layer 104 is formed to have a certain thickness which is required for obtaining oil resistance and oil penetration resistance. This is because the hard resin material shows more excellent oil resistance than that of the soft resin material. Concerning the conventional hose having the above laminated structure, as shown in Figure 23, a resin tube (a resin inner layer 104) is extrusion-molded. Then, a rubber tube (a rubber outer layer 100) is extrusion-molded and laminated on the outside of the resin inner layer 104. Furthermore, the obtained rubber tube is vulcanized or semi-vulcanized, and bent to be in the certain direction. After that, the obtained rubber tube is vulcanized to produce the hose as shown in Figure 22. The resin inner layer 104 in the inside of the obtained hose has the same thickness at either the hose main portion or the hose edge portion. Furthermore, from the prior art document US-A-4 313 629 a hose is known which comprises a resilient outer rubber layer covering an inner layer which is a resilient nylon tube. The inner nylon tube of this hose extends up to the end portions of the hose. In particular, the end portions of the hose have a region where the inner nylon tube has merely a reduced thickness. Due to continuously raising requirements concerning the oil resistance and the oil penetration resistance, the hard resin material must have a certain considerable thickness which is required for obtaining the desired improved oil resistance and oil penetration resistance. However, such a structure raises the disadvantage that a mating pipe of metal which has to be inserted into the inner side of the hose edge portion cannot be fully adhered to the inside of the hose edge portion, thereby not obtaining enough sealing. Therefore, it is an object of the present invention to provide a multi-layered hose which can be low-cost manufactured while excellent oil resistance and oil penetration resistance qualities as well as a sufficient sealing by the mating with a mating pipe is obtained. This object is achieved by a multi-layered hose according to claims 1 or 11. Further advantageously improvements of such multi-layered hoses according to claims 1 and 11 are the subject-matter of the dependent claims. In view of an axial direction, a multi-layered hose according to the present invention comprises two edge portions for forming both side portions, and a central portion for connecting side portions. A nipple made of a metal or a hard resin is inserted into the edge portion. The central portion is a main portion, and it is formed in straight-shaped, curve-shaped or bellows-shaped. When the multi-layered hose according to the present invention is used as a filler hose for automobiles and when the inner layer is made of resin, it is desirable that the resin material for forming the inner layer has an excellent oil penetration resistance in which the penetration constant is not more than 5mg·mm/cm 2 ·day. Furthermore, it is preferable that the penetration constant is not more than 1mg·mm/cm 2 ·day, and more preferably, not more than 0.3mg·mm/cm 2 ·day. The oil penetration constant is measured as follows. A cup is filled with gasoline, and a resin film having the thickness of 1mm is attached to the upper surface of the cup in order not to leak gasoline. While maintaining the condition that the film is contacted to gasoline, the cup is let alone at the temperature of 40°C, and a decreased weight is measured at every 24 hours. After being stabled, the decreased weight of the resin film per 1mm and 1 cm 2 (mg·mm/cm 2 ·day) is calculated, and it is determined as the oil penetration constant. Concerning the multi-layered hose according to the present invention, when the inner layer is made of resin, the thickness of the inner layer is in the range of 0.01 to 1mm, preferably, in the range of 0.05 to 0.7mm, more preferably, in the range of 0.1 to 0.4mm. When a thin resin inner layer is formed at the inner periphery surface of the hose edge portion, the thickness of the thin resin inner layer is not more than 0.1mm, preferably, not more than 0.05mm. The inner layer can be formed at a part of the inner periphery surface of the edge portion near the main portion. The multi-layered hose according to the present invention can be used as other hose except as a filler hose. The outer layer can be a single rubber layer or a multiple of rubber layers. In the rubber layer, a reinforced thread or a reinforced cloth can be disposed. Concerning one multi-layered hose according to the present invention, no resin inner layer is formed at the inner periphery surface of the hose edge portion into which the mating member is inserted. Concerning another multi-layered hose according to the present invention, a resin inner layer is formed at the inner periphery surface of a main portion of an outer layer and at a part of the inner periphery surface of an edge portion near the main portion of the outer layer. In the first multi-layered hose of the invention, no resin inner layer is formed at the inner periphery surface of the hose edge portion into which the mating member is inserted. A resin inner layer is formed at the inner periphery surface of the hose main portion. Since no resin inner layer is formed at the inner periphery surface of the hose edge portion, a mating pipe is satisfactorily adhered to the inside of the hose edge portion when the mating pipe is inserted into the hose edge portion, thereby obtaining enough sealing at the connecting edge portion. Furthermore, the inner side of the hose edge portion is covered since the mating member is inserted and engaged with the hose. Therefore, the hose is not deteriorated due to an inner fluid such as gasoline, and the penetration of gasoline doesn't occur. Therefore, the multi-layered hose according to the present invention shows excellent oil resistance and excellent oil penetration resistance. Furthermore, the multi-layered hose can be produced at low price, and it shows satisfactory sealing at the hose edge portion. Concerning the multi-layered hose in which the inner layer is formed at a part of the inner periphery surface of the hose edge portion near the main portion, sealing is deteriorated since the inner layer is made of resin. However, the inner layer is formed at the main portion and the edge portion of the hose so that the following problems don't occur. When no inner layer is formed at the inner periphery surface of the hose edge portion, a stress concentration is generated at or near a boundary between rubber and resin of the inner periphery surface due to the physical difference between rubber and resin. And, the function of an inner fluid is much different. Therefore, the edge surface portion of the resin inner layer is likely to be come off from the rubber outer layer. In the multi-layered hose according to the present invention, the resin inner layer is formed only at a part of the edge portion. Moreover, an excellent trailability for the rubber outer layer is obtained. Furthermore, a stress concentration on the edge surface portion of the resin inner layer and peeling of the edge surface of the resin inner layer due to the function of an inner fluid are effectively prevented since the hose edge portion is supported between the rubber outer layer and the mating member. Moreover, the thickness of the resin inner layer which is formed at the hose edge portion is thin, and the resin inner layer is formed only at a part of the edge portion, so flexibility at the hose edge portion is not deteriorated, and excellent sealing can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a cross-sectional view of a multi-layered hose in the First Preferred Embodiment. Figure 2 shows a main cross-sectional view of a multi-layered hose in the Second Preferred Embodiment. Figure 3 is a main cross-sectional view for showing the condition that a nipple is inserted into the edge portion of the multi-layered hose in the Second Preferred Embodiment. Figure 4 is a main cross-sectional view of a multi-layered hose in the Third Preferred Embodiment. Figure 5 is a main cross-sectional view for showing the condition that a nipple is inserted into the edge portion of the multi-layered hose in the Third Preferred Embodiment. Figure 6 is a main cross-sectional view of a multi-layered hose in the Fourth Preferred Embodiment. Figure 7 is a main cross-sectional view for showing the condition that a nipple is inserted into the edge portion of the multi-layered hose in the Fourth Preferred Embodiment. Figure 8 shows a main cross-sectional view of a multi-layered hose in the Fifth Preferred Embodiment. Figure 9 is a main cross-sectional view for showing the condition that a nipple is inserted into the edge portion of the multi-layered hose in the Fifth Preferred Embodiment. Figure 10 is a main cross-sectional view of a multi-layered hose in the Sixth Preferred Embodiment. Figure 11 is a main cross-sectional view for showing the condition that a nipple is inserted into the edge portion of the multi-layered hose in the Sixth Preferred Embodiment. Figure 12 is a main cross-sectional view of a multi-layered hose in the Seventh Preferred Embodiment. Figure 13 is a main cross-sectional view for showing the condition that a nipple is inserted into the edge portion of the multi-layered hose in the Seventh Preferred Embodiment. Figure 14 shows a main cross-sectional view of a multi-layered hose in the Eighth Preferred Embodiment. Figure 15 is a main cross-sectional view for showing the condition that a nipple is inserted into the edge portion of the multi-layered hose in the Eighth Preferred Embodiment. Figure 16 is a main cross-sectional view of a multi-layered hose in the Ninth Preferred Embodiment. Figure 17 is a main cross-sectional view for showing the condition that a nipple is inserted into the edge portion of the multi-layered hose in the Ninth Preferred Embodiment. Figure 18 is a main cross-sectional view of a multi-layered hose in the Tenth Preferred Embodiment. Figure 19 is a main cross-sectional view for showing the condition that a nipple is inserted into the edge portion of the multi-layered hose in the Tenth Preferred Embodiment. Figure 20 is a partial cross-sectional view of a conventional multi-layered hose. Figure 21 is a general cross-sectional view of another conventional multi-layered hose. Figure 22 is a general cross-sectional view of the other conventional multi-layered hose. Figure 23 is a cross-sectional view for showing a process of producing the conventional multi-layered hose. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Having generally described the present invention, a further understanding can be obtained by reference to the specific preferred embodiments which are provided herein for purposes of illustration only and are not intended to limit the scope of the appended claims. The Preferred Embodiments according to the present invention will be hereinafter described with reference to Figures 1 through 19. First Preferred Embodiment Figure 1 shows a multi-layered hose 10 of the First Preferred Embodiment. In Figure 1, the left side is a cross-sectional view, and a nipple 16 of a mating member is inserted into an upper edge portion. The multi-layered hose 10 is a filler hose for automobiles in which gasoline is transmitted. The multi-layered hose 10 comprises a main portion 14 having an inner diameter of 34mm and a bellows portion 12, and an edge portion 18 into which a nipple 16 made of a metal pipe of a mating member is inserted. Concerning composition materials, the multi-layered hose 10 comprises a rubber outer layer 20 and a resin inner layer 22 which is integrally connected with an inner periphery surface of the main portion of the outer layer 20. Between the outer layer 20 and the inner layer 22, an adhesive layer exists (not shown). The rubber materials of the outer layer 20 include NBR PVC, CR, CHC, CSH, EPDM and so on. The outer layer 20 can be a single rubber layer or a multiple of rubber layers. When the outer layer 20 is a multiple of rubber layers, the inside of the outer layer comprises rubber having excellent oil resistance, and the outside of the outer layer comprises rubber having excellent fire resistance and excellent wear resistance. In this case, the multi-layered hose shows not only excellent oil resistance but also excellent fire resistance and excellent wear resistance. The resins of the inner layer 22 include polyamide, fluorine, polyester, polyvinyl chloride, polyacetal, PPS and so on. These resins show excellent oil resistance and excellent oil penetration resistance, and an oil penetration constant is not more than 1mg·mm/cm 2 ·day. In the multi-layered hose 10, the hose main portion 14 which is exposed to an inner fluid has a laminated structure comprising the rubber outer layer 20 and the resin inner layer 22. The hose main portion 14 also has a bellows portion. Therefore, the hose main portion 14 effectively controls oil penetration due to the inner layer 22 made of resin while maintaining excellent flexibility. On the other hand, the inner layer 22 is not formed at the hose edge portion 18 so that the outer layer 20 made of flexible rubber is closely engaged with the nipple 16 of the mating member, thereby obtaining excellent sealing. The multi-layered 10 hose shows excellent flexibility, excellent oil resistance, excellent oil penetration resistance, and excellent sealing with the mating metal pipe 16. These characteristics are required for hoses. In the multi-layered hose 10, the inner layer 22 is not formed at the inner surface of the edge portion 18, but the inner surface of the edge portion 18 is engaged with the mating metal pipe 16. As a result, the inner surface of the edge portion 18 is not directly contacted to gasoline so that gasoline is not penetrated to outside through the hose edge portion 18. Concerning the main portion 14 of the multi-layered hose 10, the outer layer 20 is adhered to the inner layer 22. Therefore, it is prevented that the inner layer 22 is come off from the outer layer 20 because of negative pressure and vibration which are acted on the inside of the multi-layered hose 10, and deformation of the multi-layered hose 10. There are two kinds of methods for connecting the rubber outer layer 20 and the resin inner layer 22. One method is that an adhesive is applied to the inner surface of the rubber outer layer 20 before the resin inner layer 22 is laminated on the rubber outer layer 20. The other method is that an adhesive is kneaded into rubber of the rubber outer layer 20 and/or resin of the resin inner layer 22. In the multi-layered hose 10, a core bar (not shown) is used, and it has the same shape as that of the hose hole. On the outer surface of the core bar, a resin film for forming the inner layer 22 is formed. After that, an adhesive is coated on the surface of the resin film. Then, a predetermined unvulcanized rubber is coated on the core bar having the resin film. Finally, the obtained core bar is put into a metallic mold and heated to be vulcanized-molding. In order to take out the obtained multi-layered hose from the core bar and the metallic mold, they are preferably a combination type comprising many parts. In stead of coating the adhesive on the resin film, it is effective that the resin film is activated. This activated method include a sodium-etching treatment, a surface oxidized treatment due to plasma flame, a physical treatment such as sputtering, and so on. When the resin surface is activated, rubber is valcanized and adhered to the resin surface to complete the strong connection between rubber and resin. The other method for producing the multi-layered hose is as follows. At first, rubber for forming the outer layer 22 is injection-molded to obtain a rubber compact. Then, an edge portion of the inner periphery surface of the obtained rubber compact is masked, and resin powder is coated to the inner periphery surface of the main portion in the same method as static powder coating. After that, the obtained hose is heated and the resin powder is melted to be the inner layer. In this method, the rubber compact for forming the outer layer can be valcanized at the time of molding, or it can be molded without being valcanized. Concerning the latter case, the rubber compact is vulcanized by heat which is generated at the time when the resin powder is melted. Second Preferred Embodiment Figure 2 shows a main cross-sectional area of a multi-layered hose 10 of the Second Preferred Embodiment. Figure 3 shows a main cross-sectional area of the multi-layered hose 10 of the Second Preferred Embodiment when the nipple 16 is inserted into the edge portion of the multi-layered hose 10. In the multi-layered hose 10, the inner diameter of the edge portion 18 is smaller than that of the main portion 14. Namely, the thickness of the multi-layered hose 10 is thick at the edge portion, and a low stepping portion 24 is disposed between the main portion 14 and the edge portion 18. The edge surface of the resin inner layer 22 is contacted to the stepping portion 24 on the inner periphery surface of the rubber outer layer 20. In the multi-layered hose 10, the edge surface of the inner layer 22 is covered with the stepping portion 24 on the inner periphery surface of the outer layer 20 so that the inner layer 22 is hardly come off from the edge surface. As shown in Figure 3, the large diameter portion on the outer periphery of the tip portion of the nipple 16 is engaged with the edge of the main portion 14. At this time, the inner periphery diameter of the main portion 14 is larger than that of the edge portion 18. As a result, the edge of the inner layer 22 is not greatly enlarged by the tip portion of the nipple 16. Therefore, the extension of the inner layer 22 becomes less. The multi-layered hose 10 of the Second Preferred Embodiment is produced by the same method as that of the First Preferred Embodiment. Third Preferred Embodiment Figure 4 shows a main cross-sectional area of a multi-layered hose 10 of the Third Preferred Embodiment. Figure 5 shows a main cross-sectional area of the multi-layered hose 10 of the Third Preferred Embodiment when the nipple 16 is inserted into the edge portion of the multi-layered hose 10. In the multi-layered hose 10, a ring-shaped groove 25 is disposed at a boundary portion between the edge portion 18 and the main portion 14 of the rubber outer layer 20. As shown in Figure 4, the ring-shaped groove 25 has the sectional shape in which the inner periphery diameter increases from the main portion 14 toward the edge portion 18 and it becomes small at the edge portion 18. The edge of the resin inner layer 22 is disposed at the largest inner periphery diameter portion of the ring-shaped groove 25, and the edge surface of the inner layer 22 is contacted to the inner wall of the ring-shaped groove 25. The multi-layered hose 10 of the Third Preferred Embodiment has the same functions and effects as those of the multi-layered hose 10 of the Second Preferred Embodiment. The inner layer 22 is hardly come off from its edge surface. And, the edge of the inner layer 22 is not greatly enlarged by the tip portion of the nipple 16. Therefore, the extension of the inner layer 22 becomes less. Fourth Preferred Embodiment Figure 6 shows a main cross-sectional area of a multi-layered hose 10 of the Fourth Preferred Embodiment. Figure 7 shows a main cross-sectional area of the multi-layered hose 10 of the Fourth Preferred Embodiment when the nipple 16 is inserted into the edge portion of the multi-layered hose 10. In the multi-layered hose 10, a ring-shaped projected portion 26 and the ring-shaped groove 25 are disposed at a boundary portion between the edge portion 18 and the main portion 14 of the rubber outer layer 20 from the main portion 14 toward the edge portion 18. As shown in Figure 6, the projected portion 26 is trapezoid in cross-sectional view and it circulates the inner periphery surface. The edge of the resin inner layer 22.is disposed at the largest inner periphery diameter portion of the ring-shaped groove 25, and the edge surface of the inner layer 22 is contacted to the inner wall of the ring-shaped groove 25. The multi-layered hose 10 of the Fourth Preferred Embodiment has the same functions and effects as those of the multi-layered hose 10 of the Second or Third Preferred Embodiment. The inner layer 22 is hardly come off from its edge surface. And, the edge of the inner layer 22 is not greatly enlarged by the tip portion of the nipple 16. Therefore, the extension of the inner layer 22 becomes less. Furthermore, the tip of the nipple 16 is contacted to and engaged with the side surface of the ring-shaped projected portion 26. As a result, the degree of the insertion of the nipple 16 is certainly known, and disadvantages due to an insufficient insertion of the nipple 16 can be prevented. Therefore, the multi-layered hose 10 is firmly engaged with the nipple 16. The top side of the multi-layered hose 10 is easily subjected by stress concentration when the nipple 16 is inserted into the multi-layered hose 10. Since the top side of the multi-layered hose 10 includes the projected portion 26, the multi-layered hose 10 is thick, thereby improving its wear resistance. In the Fourth Preferred Embodiment, the projected portion 26 can be separated into two or three with the predetermined distance in the circumferential direction, or the projected portion 26 can be replaced by a multiple of projections which are arranged in the circumferential direction. Fifth Preferred Embodiment Figure 8 shows a main cross-sectional area of a multi-layered hose 10 of the Fifth Preferred Embodiment. Figure 9 shows a main cross-sectional area of the multi-layered hose 10 of the Fifth Preferred Embodiment when the nipple 16 is inserted into the edge portion of the multi-layered hose 10. In the multi-layered hose 10, the inner diameter of the edge portion 18 is larger than that of the main portion 14. Namely, the thickness of the multi-layered hose 10 is thin at the edge portion, and a low stepping portion 27 is disposed between the main portion 14 and the edge portion 18. The inner layer 22 is formed only at the inner periphery surface of the main portion 14, and the edge surface of the inner layer 22 and the rubber outer layer 20 constitute the edge portion 18. In the multi-layered hose 10, since the low stepping portion 27 is disposed between the main portion 14 and the edge portion 18, the tip of the nipple 16 is contacted to the edge surface of the stepping portion 27 when the nipple 16 is inserted into the edge portion 18. Therefore, the tip of the nipple 16 is also contacted to the edge surface of the inner layer 22 so that a fluid in the multi-layered hose 10 is not directly contacted to the rubber outer layer 20. In this embodiment, since the thickness of the edge portion is thinner than that of the main portion 14, the nipple 16 is easily detached. The multi-layered hose 10 of the Fifth Preferred Embodiment is produced by the same method as that of the First Preferred Embodiment. Sixth Preferred Embodiment Figure 10 shows a main cross-sectional area of a multi-layered hose 10 of the Sixth Preferred Embodiment. Figure 11 shows a main cross-sectional area of the multi-layered hose 10 of the Sixth Preferred Embodiment when the nipple 16 is inserted into the edge portion of the multi-layered hose 10. In the multi-layered hose 10, the low stepping portion 27 and a ring-shaped projected portion 28 are disposed at the inner periphery surface between the main portion 14 and the edge portion 18. The resin inner layer 22 is formed at the inner periphery surface of the main portion 14 including the projected portion 28. The rubber outer layer 20 has the same thickness at both the main portion 14 and the edge portion 18 except at the projected portion 28. The multi-layered hose 10 of the Sixth Preferred Embodiment has the same functions and effects as those of the multi-layered hose 10 of the Fifth Preferred Embodiment. Furthermore, the above multi-layered hose 10 has the projected portion 28 so that the multi-layered hose 10 is firmly engaged with the nipple 16 as shown in the Fourth Preferred Embodiment. Therefore, the multi-layered hose 10 shows excellent wear resistance. Seventh Preferred Embodiment Figure 12 shows a main cross-sectional area of a multi-layered hose 10 of the Seventh Preferred Embodiment. Figure 13 shows a main cross-sectional area of the multi-layered hose 10 of the Seventh Preferred Embodiment when the nipple 16 is inserted into the edge portion of the multi-layered hose 10. In the multi-layered hose 10, a ring-shaped projected piece 31 in which the thickness in the axial direction is thin is disposed at a boundary portion between the edge portion 18 and the main portion 14. The resin inner layer 22 is contacted to the side surface of the projected piece 31. As shown in Figure 13, the projected piece 31 is pushed by the tip of the nipple 16 to cover the edge portion of the inner layer 22. Namely, the projected piece 31 exists between the tip portion of the nipple 16 and the edge portion of the inner layer 22 to seal a clearance between them. Therefore, a fluid leaked along the surface of the nipple 16 is certainly prevented. The multi-layered hose 10 of the Seventh Preferred Embodiment is produced by the same method as that of the First Preferred Embodiment. Eighth Preferred Embodiment Figure 14 shows a main cross-sectional area of a multi-layered hose 10 of the Eighth Preferred Embodiment. Figure 15 shows a main cross-sectional area of the multi-layered hose 10 of the Eighth Preferred Embodiment when the nipple 16 is inserted into the edge portion of the multi-layered hose 10. In the multi-layered hose 10, the ring-shaped groove 25 as shown in Figure 4 and a ring-shaped projected piece 31 which circulate the inner periphery surface are disposed at a boundary portion between the edge portion 18 and the main portion 14 from the main portion 14 toward the edge portion 18. The edge of the resin inner layer 22 is disposed at the bottom of the ring-shaped groove 25. The ring-shaped groove 25 and the ring-shaped projected piece 31 are projected or recessed toward the inclining direction against the axis of the multi-layered hose 10. The above projected piece 31 has the same sealing function as that of the projected piece 31 of the Seventh Preferred Embodiment. The edge of the inner layer 22 is extended to the bottom of the ring-shaped groove 25. Since the diameter of the ring-shaped groove 25 increases toward the edge portion, the ring-shaped groove 25 is not deformed by the tip of the nipple 16 when the nipple 16 is inserted, thereby improving wear resistance. The projected piece 31 can seal in wide ranges, and sealing capacity is improved. Ninth Preferred Embodiment Figure 16 shows a main cross-sectional area of a multi-layered hose 10 of the Ninth Preferred Embodiment. Figure 17 shows a main cross-sectional area of the multi-layered hose 10 of the Ninth Preferred Embodiment when the nipple 16 is inserted into the edge portion of the multi-layered hose 10. In the multi-layered hose 10, the ring-shaped projected portion 26 and the ring-shaped projection groove 25 as shown in Figure 6 and the ring-shaped projected piece 31 as shown in Figure 14 are disposed at a boundary portion between the edge portion 18 and the main portion 14. The resin inner layer 22 covers the surface of the projected-line 26, and the edge of the inner layer 22 is disposed at the bottom of the ring-shaped groove 25. The above projected piece 31 has the same sealing function as that of the projected piece 31 of the Seventh Preferred Embodiment. The edge of the inner layer 22 is extended to the bottom of the ring-shaped groove 25. Since the diameter of the ring-shaped groove 25 increases toward the edge portion, the ring-shaped groove 25 is not deformed by the tip of the nipple 16 when the nipple 16 is inserted, thereby improving wear resistance. The projected piece 31 can seal in wide ranges, and sealing capacity is improved. Furthermore, the projected portion 26 is disposed at the tip of the nipple 16 when the nipple 16 is inserted so that the multi-layered hose 10 is firmly engaged with the nipple 16 as shown in the Fourth Preferred Embodiment. Therefore, the multi-layered hose 10 shows excellent wear resistance. Tenth Preferred Embodiment Figure 18 shows a main cross-sectional area of a multi-layered hose 10 of the Tenth Preferred Embodiment. Figure 19 shows a main cross-sectional area of the multi-layered hose 10 of the Tenth Preferred Embodiment when the nipple 16 is inserted into the edge portion of the multi-layered hose 10. In the multi-layered hose 10, the ring-shaped projected portion 26 as shown in Figure 6 and the projected piece 31 as shown in Figure 12 are disposed at a boundary between the edge portion 18 and the main portion 14 with a certain distance from each other in the axial direction. And, the edge surface of the inner layer 22 is contacted to the side surface of the projected piece 31. The above projected piece 31 has the same sealing function as that of the projected piece 31 of the Seventh Preferred Embodiment. The projected portion 26 is disposed at the tip of the nipple 16 when the nipple is inserted, thereby improving wear resistance of the multi-layered hose 10.

Claims: A multi-layered hose (10) comprising a rubber outer layer (20) and a resin inner layer (22) integrally formed at the inner periphery surface of said outer layer (20), and having an edge portion (18) into which a mating member is inserted, characterized in that said inner layer (22) is formed at the inner periphery surface of a main portion (14) of said hose except that said edge portion (18). A multi-layered hose (10) according to claim 1, wherein the inner periphery diameter of an edge portion (18) of said outer layer (20) is smaller than that of a main portion (14) of said outer layer (20), and said outer layer (20) comprises a stepping portion (24) between said main portion (14) and said edge portion (18), and each of two edge surfaces of said inner layer (22) is contacted to said stepping portion (24). A multi-layered hose (10) according to claim 1, wherein the inner periphery diameter of an edge portion (18) of said outer layer (20) is larger than that of a main portion (14) of said outer layer (20), and said outer layer (20) comprises a stepping portion (27) between said main portion (14) and said edge portion (18), and each of two edge surfaces of said inner layer (22) is exposed to said stepping portion (27). A multi-layered hose (10) according to claim 1, wherein a projected portion (26) which encircles the inner periphery is disposed between said main portion (14) and said edge portion (18) of said outer layer (20), and said projected portion (26) is used as a stopper for said mating member. A multi-layered hose (10) according to claim 1, wherein a multiple of projected portions or projections which are arranged in the circumferential direction with the predetermined distance are disposed between said main portion (14) and said edge portion (18) of said outer layer (20), and said projected portions (26) or projections are used as a stopper for said mating member. A multi-layered hose (10) according to claim 1, wherein a flange-shaped projected piece (31) which encircles the inner periphery is disposed between said main portion (14) and said edge portion (18) of said outer layer (20), and said projected piece (31) is pushed by the tip portion of said mating member and pressed to the inner periphery surface of an edge portion (18) of said inner layer (10) to seal said inner periphery surface of said edge portion (18) and said mating member. A multi-layered hose (10) according to claim 1, wherein a ring-shaped groove (25) which encircles the inner periphery is disposed between said main portion (14) and said edge portion (18) of said outer layer (20), and the tip portion of said mating member has a projected portion on its outer periphery surface, and said projected portion is engaged with said groove (25). A multi-layered hose (10) according to claim 7, wherein an edge portion (18) of said inner layer (22) extends to the bottom of said ring-shaped groove (25). A multi-layered hose (10) according to claim 1, wherein a ring-shaped groove (25) which encircles the inner periphery is disposed between said main portion (14) and said edge portion (18) of said outer layer (20), and a flange-shaped projected piece (31) which encircles the inner periphery is disposed at an opening side of said groove (25), and a projected portion is disposed at an outer periphery surface of the tip portion of said mating member, and said projected portion is engaged with said groove, and said projected portion is pushed by the tip portion of said mating member to seal the inner periphery surface and said mating member. A multi-layered hose (10) according to claim 9, wherein said edge portion (18) of said inner layer (10) extends to the bottom of said ring-shaped groove (25). A multi-layered hose (10) comprising a rubber outer layer (20) (20) and a resin inner layer (22) integrally formed at the inner periphery surface of said outer layer (20), and having an edge portion (18) into which a mating member is inserted, wherein said inner layer (22) is formed at the inner periphery surface of a main portion (14) of said outer layer (20) and characterized in that said inner layer (22) is formed at a part of the inner periphery surface of an edge portion (18) near said main portion (14) of said outer layer (20). A multi-layered hose (10) according to claim 11, wherein said inner layer (22) formed at a part of the inner periphery surface of said edge portion (18) of said outer layer (20) is a straight tube having a fixed inner periphery diameter, and the tip portion of said mating member is in the shape of a straight tube having the outer periphery diameter which is engaged with the inner periphery of said inner layer (22).

Inventors: KAWASAKI MINORU, KAWASAKI, MINORU, Kawasaki, Minoru, c/o TOKAI RUBBER IND., LTD.
Applicants: TOKAI RUBBER IND LTD, TOKAI RUBBER INDUSTRIES, LTD.
Application year: 1993
Main classification: F16L33
IPC codes: F16L11, F16L33