Rubber Hose with Fitting and Method for Manufacturing the Same

Abstract

To provide a rubber hose with a mouthpiece which can inhibit burrs from occurring on an inner surface of the mouthpiece, and to provide a manufacturing method of the rubber hose.SOLUTION: A rubber hose with a mouthpiece of the invention includes: a rubber hose body 3 having an inner surface rubber layer 1 and an outer rubber layer 2 formed at a radial outer side of the inner surface rubber layer 1; and mouthpieces 4 fixed to both ends of the rubber hose body 3. The inner surface rubber layer 1 is formed so as to contact with each mouthpiece 4 in a rubber hose length direction X, and the outer rubber layer 2 is formed so as to cover the inner surface rubber layer 1 and a base end of each mouthpiece 4. At least a part of a surface 6, which contacts with the inner surface rubber layer 1 in the rubber hose length direction X, of the mouthpiece 4 is formed as an inclined surface and / or a step surface.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a rubber hose with a fitting and a method for manufacturing the same, which can be suitably used for applications such as transporting fluids in which solids are mixed, such as fresh concrete and earth and sand water.

Background Art

[0002] As a method for manufacturing a rubber hose with fittings in which fittings are fixed to both axial ends of a rubber hose body, as shown in FIG. 11, an inner rubber layer 21 made of unvulcanized rubber is formed on a mandrel B, and an outer rubber layer composed of an outer rubber layer, a cord reinforcing rubber layer, a wire reinforcing rubber layer, etc. is formed on the outer peripheral side of the inner rubber layer 21 to form an unvulcanized rubber hose body 23, and a method of vulcanizing this is known (see Patent Document 1). Both ends in the length direction of the rubber hose body 23 are formed so as to cover the base end portions of the fittings 24, and the fittings 24 are fixed to both ends of the rubber hose body 23 by vulcanizing the rubber hose body 23.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Incidentally, after the base metal fitting 24 is externally inserted onto the mandrel B, its inner diameter is formed to be about 1 mm larger than the outer diameter of the mandrel B in order to be slidable on the mandrel B. Therefore, in a state where the base metal fitting 24 is externally inserted onto the mandrel B, a gap C is formed between the lower part of the mandrel B and the base metal fitting 24. The unvulcanized rubber hose body 23 is heated and vulcanized in a vulcanizing can while its outer periphery is wrapped and pressurized. Therefore, when the inner rubber layer 21 melts due to heating, the melted inner rubber flows toward both ends of the rubber hose body, and as shown in FIG. 12, there is a problem that burrs E are generated by leaking from the gap C between the lower part of the mandrel B and the base metal fitting 24.

[0005] The generated burrs not only impair the appearance of the rubber hose with the base metal fitting, but also increase the fluid resistance due to the burrs during fluid conveyance, and there is a risk that the burrs may peel off and mix into the fluid.

[0006] Therefore, an object of the present invention is to provide a rubber hose with a base metal fitting and a method for manufacturing the same that can suppress burrs generated on the inner surface of the base metal fitting.

Means for Solving the Problems

[0007] In order to solve the above problems, as one aspect of the present invention, a rubber hose body having an inner rubber layer and an outer rubber layer formed on the outer side in the radial direction of the inner rubber layer, and base metal fittings fixed to both ends of the rubber hose body are provided. The inner rubber layer is formed to abut against the base metal fitting in the length direction of the rubber hose, and the outer rubber layer is a rubber hose with a base metal fitting formed to cover the inner rubber layer and the base end portion of the base metal fitting, and at least a part of the surface of the base metal fitting that abuts against the inner rubber layer in the length direction of the rubber hose is an inclined surface and / or a stepped surface.

[0008] The outer rubber layer may be configured to include a wire-reinforced rubber layer reinforced by a spirally wound wire, a cord-reinforced rubber layer formed on the inner and outer surfaces of the wire-reinforced rubber layer, and an outer rubber layer as the outermost layer.

[0009] A diameter-expanded portion capable of accommodating the end portion of the rubber hose in the length direction of the inner rubber layer is formed at the base end portion of the fitting, and a surface that contacts the inner rubber layer may be formed in the diameter-expanded portion.

[0010] As a method for manufacturing a rubber hose with a fitting having the above configuration, specifically, a rubber hose with a fitting including a rubber hose body having an inner rubber layer and an outer rubber layer formed on the outer side in the radial direction of the inner rubber layer, and fittings fixed to both ends of the rubber hose body, an inner rubber layer forming step of forming the unvulcanized inner rubber layer on the outer peripheral surface of the mandrel; a cylindrical fitting is externally inserted onto the mandrel on which the inner rubber layer is formed, the fitting is slid in the axial direction of the mandrel, and the unvulcanized outer rubber layer is formed so as to cover the inner rubber layer and the base end portion of the fitting in a state where the fitting abuts against the axial end surface of the inner rubber layer; an outer rubber layer forming step; after the outer rubber layer forming step, a vulcanization step of vulcanizing the unvulcanized inner rubber layer and the outer rubber layer is provided, at least a part of the surface of the fitting that contacts the inner rubber layer in the length direction of the rubber hose is an inclined surface and / or a stepped surface, a space portion is formed between the inclined surface and / or the stepped surface and the end surface of the inner rubber layer in the length direction of the rubber hose after the outer rubber layer forming step, and the inner rubber of the inner rubber layer that flows in the vulcanization step may be caused to flow into the space portion.

Effect of the Invention

[0011] According to the rubber hose with a fitting according to one aspect of the present invention, since at least a part of the surface of the fitting that contacts the inner rubber layer in the length direction of the rubber hose is an inclined surface and / or a stepped surface, in the manufacturing process of the rubber hose with a fitting, when the fitting is brought into contact with the end surface of the unvulcanized inner rubber layer in the length direction of the rubber hose, a space portion is formed between the inclined surface and / or the stepped surface and the end surface of the inner rubber layer in the length direction of the rubber hose. Then, in the vulcanization step, since the flowed inner rubber is accommodated in the space portion, it is possible to suppress the generation of burrs on the inner surface of the fitting.

Brief Description of the Drawings

[0012]

Figure 1

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Modes for Carrying Out the Invention

[0013] [First Embodiment] Hereinafter, the first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing the rubber hose with a base metal fitting of this embodiment, and FIG. 2 is an enlarged view showing the base metal fitting and the inner rubber layer of the portion surrounded by the circular frame A in FIG. 1. In the figure, arrow X indicates the length direction of the rubber hose (which coincides with the axial direction of the mandrel B and the horizontal direction), and arrow Y indicates the vertical direction, respectively.

[0014] As shown in Fig. 1, the rubber hose with a fitting of the present embodiment includes a rubber hose body 3 having an inner rubber layer 1 and an outer rubber layer 2 formed on the radially outer side of the inner rubber layer 1, and fittings 4 fixed to both ends of the rubber hose body 3 in the rubber hose length direction. Note that Fig. 1 shows the state of the rubber hose with a fitting immediately after vulcanization on the mandrel B, and the rubber hose with a fitting can be obtained by removing the mandrel B.

[0015] The inner rubber layer 1 is formed so as to abut on the fitting 4 in the rubber hose length direction X, and the outer rubber layer 2 is formed so as to cover one end portion in the length direction of the inner rubber layer 1 and the fitting 4. In this article, of both ends in the length direction of the fitting 4, the side covered by the outer rubber layer 2 is defined as the base end of the fitting 4, and the side exposed from the rubber hose body 3 is defined as the tip of the fitting 4. And the portion of the fitting 4 covered by the outer rubber layer 2 is defined as the base end portion of the fitting 4. An expanded diameter portion 5 is formed on the inner surface on the base end portion side of the fitting 4. The inner rubber layer 1 is in a state of entering into the expanded diameter portion 5. A surface 6 (hereinafter abbreviated as the inner rubber abutting surface) that abuts on the end surface of the inner rubber layer 1 in the rubber hose length direction X is formed in the expanded diameter portion 5.

[0016] At least a part of the inner rubber abutting surface 6 is an inclined surface and / or a stepped surface. In the present embodiment, the inner rubber abutting surface 6 is a tapered inclined surface whose inner diameter becomes smaller toward the tip side of the fitting 4, but it may be an inclined surface that inclines in a curved shape. Further, the inner rubber abutting surface 6 may be a stepped surface having a step in the rubber hose length direction X.

[0017] As shown in Fig. 1, in the present embodiment, as the outer rubber layer 2, a wire-reinforced rubber layer 7 reinforced by a wire wound in a spiral shape, a cord-reinforced rubber layer 8 formed on the inner surface and the outer surface of the wire-reinforced rubber layer 7, and an outer rubber layer 9 as the outermost layer are provided. The wire-reinforced rubber layer 7 is composed of a hard steel wire as a wire and a coating rubber that coats the wire, whereby it is possible to obtain a rubber hose excellent in pressure resistance and buckling resistance. For the sake of convenience, the hatching of the cross section of the outer rubber layer 2 is omitted.

[0018] The cord-reinforced rubber layer 8 is made of a sheet-like material obtained by topping an unvulcanized rubber known in the art on a woven cord fabric (cord) made of fibers. Examples of the fibers used for the cord include organic fibers such as rayon, nylon, polyester, aramid, and carbon, as well as inorganic and metal fibers such as glass and steel.

[0019] In this embodiment, two layers of the cord-reinforced rubber layer 8 are laminated on the inner surface side of the wire-reinforced rubber layer 7, and the adjacent cord-reinforced rubber layers 8, 8 are arranged such that the inclination angles of the cords intersect symmetrically with respect to the axial direction of the mandrel B. The cord-reinforced rubber layer 8 on the outer surface side of the wire-reinforced rubber layer 7 is formed in one layer for the purpose of protecting the wire-reinforced rubber layer 7. Although the formation of the outer rubber layer 9 is not necessarily required, it is possible to protect the cord-reinforced rubber layer 8 and improve the durability of the rubber hose.

[0020] A stop ring 11 that continuously projects in the circumferential direction is formed on the outer peripheral surface of the base end portion of the fitting 4. The two cord-reinforced rubber layers 8, 8 on the inner surface side of the wire-reinforced rubber layer 7 are folded back so as to be hung on the bead ring 12 at a position beyond the stop ring, thereby preventing the fitting 4 from coming out of the rubber hose body 3.

[0021] The base compounding of the unvulcanized rubber used for the inner rubber layer 1, the cord-reinforced rubber layer 8, the wire-reinforced rubber layer 7, and the outer rubber layer 9 is not particularly limited, and any compounding known in the art in this field can be used. For example, natural rubber (NR), styrene-butadiene rubber (SBR), or a blend composition of NR and cis-1,4-polybutadiene rubber (BR) and / or SBR, which are excellent in abrasion resistance, water resistance, and processability, can be mentioned.

[0022] A method for manufacturing a rubber hose with a fitting having the above-described configuration will be described. First, an inner rubber layer 1 is formed on the outer peripheral surface of a mandrel B (inner rubber layer forming step). FIG. 3 is a cross-sectional view showing a state in which a fitting 4 is externally inserted into the mandrel B, or rather, a state in which the mandrel B is inserted into the fitting 4, after the inner rubber layer 1 is formed on the outer peripheral surface of the mandrel B. The inner diameter of the fitting 4 is formed to be slightly larger than the outer diameter of the mandrel B, so that a gap C is formed between the inner surface of the lower part of the fitting 4 and the outer surface of the lower part of the mandrel B.

[0023] FIG. 4 is a cross-sectional view showing a state in which the fitting 4 externally inserted into the mandrel B is slid, and the inner rubber layer 1 is inserted into the enlarged diameter portion 5 until the inner rubber layer 1 abuts against the inner rubber contact surface 6. FIG. 5 is an enlarged view of the portion surrounded by the circular frame D in FIG. 4. By forming the enlarged diameter portion 5 in the fitting 4 and inserting the inner rubber layer 1 therein, it is possible to suppress the relative displacement between the fitting 4 and the inner rubber layer 1 in the length direction X of the rubber hose when forming the outer rubber layer 2, and it becomes possible to stably form the outer rubber layer 2.

[0024] As described above, the inner rubber contact surface 6 is an inclined surface, and when the inner rubber layer 1 reaches the inner rubber contact surface 6, further entry is restricted. That is, the inner rubber contact surface 6 has a function as a stopper that prevents further entry of the inner rubber layer 1. Further, since the inner rubber contact surface 6 is an inclined surface inclined with respect to the length direction X of the rubber hose, a space portion 13 is formed between the inner rubber contact surface 6 and the end surface 1a of the inner rubber layer in the length direction X of the rubber hose (hereinafter abbreviated as the end surface of the inner rubber layer). More specifically, a space portion 13 surrounded by the inner rubber contact surface 6, the end surface 1a of the inner rubber layer, and the mandrel B is formed.

[0025] As shown in FIG. 6, in a state where the fitting 4 abuts against the end surface 1a of the inner rubber layer 1, an unvulcanized outer rubber layer 2 is formed so as to cover the base end portions of the inner rubber layer 1 and the fitting 4 (outer rubber layer forming step). After the outer rubber layer 2 forming step, the outer periphery of the rubber hose body 3 is wrapped, and in that state, it is housed in a vulcanizing can and heated, so that the unvulcanized inner rubber layer 1 and outer rubber layer 2 are vulcanized (vulcanizing step).

[0026] In this embodiment, a space portion 13 is interposed between the end surface 1a of the inner rubber layer and the gap C. Therefore, when heating in a state where the outer periphery of the rubber hose body 3 is wrapped and pressurized, the molten inner rubber layer flows toward both ends of the rubber hose body due to the pressure of the wrapping, and the inner rubber flows into the space portion 13. In other words, if the space portion 13 is not filled with the inner rubber, it will not leak out as burrs from the gap C. Accordingly, as shown in FIGS. 1 and 2, it is possible to suppress the molten inner rubber from leaking out from the gap C between the lower part of the mandrel B and the fitting 4. Note that the space portion 13 is preferably formed to a size such that it is filled with the inner rubber that has flowed in, but a part of the space may remain in the space portion 13 after the vulcanization process.

[0027] [Second Embodiment] In this embodiment, a diameter-expanded portion is not formed on the inner surface of the base end side of the fitting, and the base end surface of the fitting is characterized as the inner rubber contact surface. Other configurations are the same as those in the first embodiment. Note that in this embodiment, members having the same names as those in the first embodiment are given the same reference numerals for convenience.

[0028] FIG. 7 is an enlarged view showing a state in which the fitting 4 of this embodiment externally inserted into the mandrel B is slid as in FIG. 5 in the first embodiment, and the inner rubber layer 1 is in contact with the inner rubber contact surface 6. As shown in the figure, a tapered inclined surface with a smaller inner diameter as it goes toward the tip side of the fitting 4 is formed on the base end surface of the fitting 4, and this inclined surface is the inner rubber contact surface 6. And a space portion 13 is formed between the inner rubber contact surface 6 and the end surface 1a of the inner rubber layer. More specifically, a space portion 13 surrounded by the inner rubber contact surface 6, the end surface 1a of the inner rubber layer, and the mandrel B is formed. After the outer rubber layer forming process, by performing the vulcanization process, the inner rubber flows into the space portion 13, and the point that the generation of burrs can be suppressed is the same as in the first embodiment.

[0029] [Third Embodiment] In this embodiment, instead of making the inner rubber contact surface an inclined surface, it is a surface orthogonal to the length direction X of the rubber hose, and a part of it is a stepped surface, which is characteristic. Other configurations are the same as those in the first embodiment. In this embodiment, members with the same names as those in the first embodiment are assigned the same reference numerals for convenience.

[0030] FIG. 8 is an enlarged view showing a state in which the fitting 4 of this embodiment externally inserted on the mandrel B is slid as in FIG. 5 in the first embodiment, and the inner rubber layer 1 is in contact with the inner rubber contact surface 6. As shown in the drawing, an inner rubber contact surface 6 that contacts the end face 1a of the inner rubber layer in the length direction X of the rubber hose is formed inside the diameter-expanded portion 5. The inner rubber contact surface 6 includes a first contact surface 6a and a stepped surface 6b having a step in the length direction X of the rubber hose with respect to the first contact surface 6a.

[0031] When the fitting 4 having the above configuration is externally inserted on the mandrel B and slid toward the inner rubber layer 1, when the end face 1a of the inner rubber layer contacts the first contact surface 6a, the entry of the end face 1a of the inner rubber layer further into the tip direction of the fitting 4 is restricted (the sliding of the fitting 4 in the length direction X of the rubber hose is restricted). A part of the inner rubber contact surface 6 is a stepped surface 6b having a step with respect to the first contact surface 6a, and a space portion 13 is formed between the stepped surface 6b and the end face 1a of the inner rubber layer. More specifically, a space portion 13 surrounded by the stepped surface 6b, the end face 1a of the inner rubber layer, and the mandrel B is formed. After the outer rubber layer forming step, by performing the vulcanization step, the inner rubber flows into the space portion 13, and the suppression of the generation of burrs is the same as in the first embodiment.

[0032] [Fourth Embodiment] In this embodiment, the inner rubber contact surface 6 in the third embodiment includes the first contact surface 6a and the stepped surface 6b, whereas the stepped portion between the first contact surface 6a and the stepped surface 6b is an inclined surface 6c, which is characteristic. Other configurations are the same as those in the third embodiment. In this embodiment, members with the same names as those in the third embodiment are assigned the same reference numerals for convenience.

[0033] FIG. 9 is an enlarged view showing a state in which the base metal fitting 4 of the present embodiment extrapolated to the mandrel B is slid and the inner rubber layer 1 is in contact with the inner rubber contact surface 6, similar to FIG. 8 in the third embodiment. As shown in the figure, an inner rubber contact surface 6 that contacts the end surface 1a of the inner rubber layer in the rubber hose length direction X is formed in the diameter-expanded portion 5. The inner rubber contact surface 6 includes a first contact surface 6a, a stepped surface 6b having a step in the rubber hose length direction X with respect to the first contact surface 6a, and an inclined surface 6c connecting between the first contact surface 6a and the stepped surface 6b.

[0034] When the base metal fitting 4 configured as described above is extrapolated to the mandrel B and slid toward the inner rubber layer 1, when the end surface 1a of the inner rubber layer contacts the first contact surface 6a, the entry of the end surface 1a of the inner rubber layer further into the tip direction of the base metal fitting 4 is restricted. A part of the inner rubber contact surface 6 is a stepped surface 6b having a step with respect to the first contact surface 6 and a tapered inclined surface 6c, and a space portion 13 is formed between the stepped surface 6b, the inclined surface 6c, and the end surface 1a of the inner rubber layer. More specifically, a space portion 13 surrounded by the stepped surface 6b, the inclined surface 6c, the end surface 1a of the inner rubber layer, and the mandrel B is formed. After the outer rubber layer forming step, by performing the vulcanization step, it is possible to suppress the generation of burrs as in the first embodiment because the inner rubber flows into the space portion 13.

[0035] As described above, the embodiments of the present invention have been described. However, the scope of the present invention is not limited to this, and various modifications can be made without departing from the spirit of the invention. Specifically, in the present embodiment, the outer rubber layer 2 includes the outer rubber layer 9, but it is not necessarily required to include the outer rubber layer 9. Also, the configuration (single-layer configuration or multi-layer configuration) of the cord reinforcing rubber layer 8 formed on the inner and outer surfaces of the wire reinforcing rubber layer 7 can be appropriately changed.

[0036] Also, in the third or fourth embodiment, the stepped surface 6b is formed to contact the inner surface of the base metal fitting 4. However, the present invention is not limited to this. For example, as shown in FIG. 10, it is also possible to form a concave annular groove portion 14 on the first contact surface 6a toward the tip of the base metal fitting 4. In this case, the bottom surface of the annular groove portion becomes the stepped surface 6b, and a space portion is formed between the stepped surface 6b and the end surface 1a of the inner rubber layer. More specifically, a space portion surrounded by the stepped surface 6b, the side surface of the annular groove portion 14, and the end surface 1a of the inner rubber layer is formed.

[0037] That is, the space portion in the above modification is formed to be adjacent to the outside in the rubber hose length direction with respect to the end surface 1a of the inner rubber layer, similar to the space portions in the first to fourth embodiments. Thereby, after the outer rubber layer forming step, by performing the vulcanization step, the inner rubber can flow into the space portion, making it possible to suppress the generation of burrs.

[0038] The constituent elements disclosed in the present embodiment can be combined with each other, and by combining them, new technical features can be formed.

Description of Reference Numerals

[0039] 1 Inner rubber layer 2 Outer rubber layer 3 Rubber hose body 4 Base metal fitting 5 Diameter-expanded portion 6 Inner rubber contact surface 7 Wire-reinforcing rubber layer 8 Cord-reinforcing rubber layer 9 Outer surface rubber layer 11 Stop ring 12 Bead ring 13 Space portion 14 Annular groove portion B Mandrel C Gap E Burr

Claims

1. A rubber hose body having an inner rubber layer and an outer rubber layer formed radially outside the inner rubber layer, and fittings fixed to both ends of the rubber hose body, wherein the fittings have an inner rubber contact surface formed at the base end of the fittings, against which the end of the inner rubber layer in the hose length direction abuts, and the outer rubber layer is a rubber hose with fittings formed to cover the inner rubber layer and the base end of the fittings, and the fittings are a rubber hose with fittings in which at least a part of the inner rubber contact surface is an inclined surface and / or a stepped surface.

2. The rubber hose with fittings according to claim 1, wherein the outer rubber layer includes a wire-reinforced rubber layer reinforced by a spirally wound wire, a cord-reinforced rubber layer formed on the inner and outer surfaces of the wire-reinforced rubber layer, and an outer rubber layer as the outermost layer.

3. The rubber hose with fittings according to claim 1 or 2, wherein a diameter-expanded portion capable of accommodating the end of the inner rubber layer in the hose length direction is formed at the base end of the fittings, and a surface that abuts against the inner rubber layer is formed within the diameter-expanded portion.

4. A method for manufacturing a rubber hose with fittings, comprising a rubber hose body having an inner rubber layer and an outer rubber layer formed radially outside the inner rubber layer, and fittings fixed to both ends of the rubber hose body, an inner rubber layer forming step of forming the unvulcanized inner rubber layer on the outer peripheral surface of a mandrel, the fittings are cylindrical, and an inner rubber contact surface against which the end of the inner rubber layer in the hose length direction abuts is formed at the base end thereof. The fittings are externally inserted onto the mandrel on which the inner rubber layer is formed, and the fittings are slid in the axial direction of the mandrel so that the inner rubber contact surface of the fittings abuts against the end surface of the inner rubber layer in the hose length direction, and an outer rubber layer forming step of forming the unvulcanized outer rubber layer so as to cover the inner rubber layer and the base end of the fittings, a vulcanizing step of vulcanizing the unvulcanized inner rubber layer and the outer rubber layer after the outer rubber layer forming step, wherein at least a part of the inner rubber contact surface of the fittings is an inclined surface and / or a stepped surface, a space portion is formed between the inclined surface and / or the stepped surface and the end surface of the inner rubber layer in the hose length direction after the outer rubber layer forming step, and the method for manufacturing a rubber hose with fittings is such that the inner rubber of the inner rubber layer flowing during the vulcanizing step flows into the space portion.

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