JP4068699B2 - Bellows and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a bellows and a method for manufacturing the bellows, and more particularly, to a bellows with less generation of wrinkles (wrinkles) in a bellows-like wall surface and a method for manufacturing such a bellows.
[0002]
[Prior art]
Rubber bellows are used for various purposes, and for the purpose of imparting high pressure resistance, bellows with a base fabric in which a base fabric is embedded in rubber have been developed. In addition, for example, in order to improve responsiveness for the purpose of using a vibration absorbing member of a precision measuring device, there is an increasing demand for a so-called thin bellows having a thin rubber thickness.
[0003]
The structure of the bellows generally includes a pair of opposing ring-shaped facing surface portions and a bellows-like wall surface portion (a bellows-like wall surface portion) provided so as to connect the outer peripheral edge portions of these facing surface portions to each other. A plurality of peaks are formed on the wall surface. When manufacturing a bellows having such a structure as a bellows with a base fabric, first, a preform of the bellows is molded with a mold using rubber before vulcanization. Next, the base fabric is wound around the outside of the preform, and then vulcanized by heating and pressurizing in a mold. During this vulcanization, the temporarily softened rubber material penetrates into the base fabric, so that the bellows after vulcanization molding has a structure in which the base fabric is embedded.
[0004]
[Problems to be solved by the invention]
However, when the base fabric-containing bellows is molded as described above, because there are peaks and valleys on the outer peripheral edge of the bellows, a portion that extends to the base fabric and a portion that does not extend occur, and two or more stages, In particular, the bellows-shaped bellows having three or more ridges has a problem that wrinkles are easily generated and the yield of products is reduced.
[0005]
The present invention was invented under such circumstances, and its purpose is to produce a bellows that is free of wrinkles and has excellent pressure resistance, and a bellows capable of producing such a bellows with a high yield. It is to provide a method.
[0006]
[Means for Solving the Problems]
In order to solve such a problem, the bellows of the present invention is provided so that a pair of ring-shaped facing surface portions arranged so as to face each other and an outer peripheral edge portion of the facing surface portion are connected to each other. A rubber bellows with a base fabric comprising a bellows-like wall surface portion having two or more peak portions and one or more valley portions, and a base fabric integrally embedded in the facing surface portion and the bellows-like wall surface portion. There,
The stretchability of the weft yarn in the circumferential direction of the bellows of the base fabric disposed at the top of the mountain portion is set to be larger than the stretchability of the weft yarn in the circumferential direction of the bellows of the base fabric disposed in the recess of the valley portion. Is done.
[0007]
As a more preferred embodiment, in the bellows of the present invention, in the central longitudinal section of the bellows, the vertical axis is a line connecting the recesses of the valleys in the axial direction, and the peak is perpendicular to the vertical axis. The line toward the top of the horizontal axis is the horizontal axis, the intersection of the vertical axis and the horizontal axis is the center of the measurement reference position of the angle, and the horizontal axis is the 0 ° line, from the center of the measurement reference position to the top of the mountain The stretchability of the weft in the bellows circumferential direction of the base fabric disposed within the angle range of 30 ° is set larger than the stretchability of the weft in the bellows circumferential direction of the base fabric disposed in the recess of the valley portion. Composed.
[0008]
Moreover, the manufacturing method of the bellows of the present invention includes a pair of ring-shaped facing surface portions arranged so as to face each other, and two or more mountain portions provided so as to connect the outer peripheral edge portions of the facing surface portions to each other. and one or more and a bellows-shaped wall portion having a trough portion, and the preform forming step of forming the bellows preforms made unvulcanized rubber in a mold, the bellows of the base fabric located at the top of the ridges The base fabric is formed so that the stretchability of the weft yarn in the circumferential direction is greater than the stretchability of the weft yarn in the circumferential direction of the bellows located in the recessed portion of the valley portion, and is substantially cylindrical. A step of preparing a base fabric woven so as to have the form of the above, and a base fabric having the substantially cylindrical form on the bellows preform made of unvulcanized rubber formed by the preform molding step Applying and applying said application A vulcanization molding step of vulcanizing with pushing the base fabric unvulcanized rubber bellows preform at a mold, are such as to have structure.
[0009]
Moreover, the manufacturing method of the bellows of this invention is set as the structure that the substantially cylindrical form of the said base fabric is a cylindrical form as a more preferable aspect.
[0010]
Further, in the bellows manufacturing method of the present invention, as a more preferable aspect, the substantially cylindrical form of the base fabric is a ring-shaped part with a cylindrical side face part and both cylindrical opening end parts facing inward. It is set as the structure which comprises a shoulder part which follows a counter surface part.
[0011]
Moreover, the manufacturing method of the bellows of this invention is set as the structure by which the substantially cylindrical form of the said base fabric is provided with the peak part and trough part along the form of the said bellows-like wall surface part as a more preferable aspect. .
[0012]
In such the present invention, the elongation of the weft yarn of the base fabric arranged at the top of the peak portion in the bellows-like wall surface portion is set to be larger than the elongation of the weft yarn of the base fabric arranged in the recessed portion of the valley portion. Therefore, the base fabric is surely attached so as to conform to the shape of the bellows preform, and there is no wrinkle in the bellows-like wall surface during vulcanization molding in the vulcanization molding process, and pressure resistance The bellows excellent in the yield are manufactured with high yield.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0014]
Bellows <br/> Figure 1 of the present invention is a perspective view showing an embodiment of a bellows of the present invention, the bellows 2 is a plan view of the bellows shown in FIG 1, FIG 3 is shown in FIG. 2 It is an AA arrow half-section view. 1 to 3, a bellows 1 according to the present invention is configured so that a pair of opposed ring-shaped rubber facing surface portions 2A and 2B and outer peripheral edge portions of the facing surface portions 2A and 2B are connected to each other. And a rubber bellows-like wall surface portion 3 provided.
[0015]
Each of the opposing surface portions 2A and 2B has a ring-shaped flat plate shape, and has an opening 4 as a preferable aspect at the center portion, and a bead portion 5 is formed inside the inner peripheral edge portion. Further, a yarn beat 5 a is formed on the innermost surface of the bead portion 5. In principle, even if there is no opening 4, it can be connected to other parts (metal parts), but the opening 4 is necessary in consideration of workability, assemblability, structure, and the like. If the opening 4 is present, a form corresponding to it is necessary in order to ensure particularly a sealing property after assembling or to ensure a concentricity between the bellows and other parts. The structure of the bead portion 5 in the present embodiment is a structure in which such consideration has been made, and since the base fabric 10 described later has entered the tip of the bead portion 5 facing inward, when pressed, The cloth due to tension is difficult to come off. This point, sealability, concentricity, etc. are satisfactory. Further, the yarn beat 5a is formed in order to further increase the sealing performance, that is, to increase the partial surface pressure of the bead portion.
[0016]
In the present embodiment, the bellows-like wall surface portion 3 includes a plurality of peak portions 3a (three peak portions in the illustrated example) and valley portions 3b (two valley portions in the illustrated example) positioned between the peak portions 3a. have. And in this bellows 1, the continuous base fabric 10 is embedded in the opposing surface portions 2A and 2B and the bellows-like wall surface portion 3 (FIG. 3).
[0017]
As shown in FIG. 4, the base fabric 10 is composed of weft yarns arranged in the top portion 30 </ b> A of the peak portion 3 a in the bellows-shaped wall portion 3 (yarns arranged in the horizontal direction (arrow α direction in FIG. 4): The stretch in the circumferential direction of the bellows-shaped wall surface portion 3 is woven so as to be larger than the stretch of the weft arranged in the hollow portion 30B of the valley portion 3b. This is a comparison of the weft elongation in a narrow range between the top portion 30A and the hollow portion 30B (showing positions close to the uppermost point and the lowermost point, respectively). In practice, the wefts arranged in a predetermined area in the vicinity of the mountain portion 3a having a particularly high degree of deformation are used with consideration of the size of the mountain portion 3a and the convex state of the mountain portion 3a.
[0018]
More specifically, for example, as shown in FIG. 4, the top portion 30 </ b> A of the bellows-like wall surface portion 3 is set to a position of 0 °, and the weft yarn of the base fabric 10 disposed within an angle range of ± 30 ° from this position. It is woven in a substantially cylindrical shape so that the elongation is greater than the elongation of the weft yarn of the base fabric 10 arranged in the recess 3B of the valley portion 3b. The angle range of ± 30 ° is determined as a preferable range in the present invention, and this range can be appropriately changed as necessary.
[0019]
In the present invention, in order to change the stretchability of the weft while maintaining the strength of the base fabric 10, for example, a method of changing the direction of the yarn or a method of changing the weaving method is performed. Further, as a means for distinguishing and knowing the stretchability of the weft, for example, there is a method of identifying the weft by different coloring depending on the degree of stretch.
[0020]
On the other hand, warp yarns (yarns arranged in the horizontal direction (arrow β direction) in FIG. 4; so-called axial direction) are different from the above-described weft yarns and generally have the same stretchability. Although there is no restriction | limiting in particular about the specific stretchability of a warp, As an example, moderate stretchability of the middle grade of the at least 2 types of elongation used with the said weft is provided. The shape of the facing surface portions 2A and 2B is not particularly limited and is a ring-shaped flat plate shape in the illustrated example, but may be a ring shape or the like that is convex toward the outside of the bellows 1. In addition, the shape and dimensions of the bead portion 5 formed on the inner peripheral edge portions of the facing surface portions 2A and 2B can be appropriately set in consideration of the purpose of use of the bellows 1, required characteristics, and the like. In addition, line PP 'in FIG. 4 has shown the state of the base fabric 10 before being attached.
[0021]
The bellows-like wall surface portion 3 has a thickness in the range of, for example, about 0.15 to 1.8 mm, and the length of the bellows-like wall surface portion 3 (distance between the facing surface portion 2A and the facing surface portion 2B in FIG. 3). There are no particular restrictions on the number (step number), shape, dimensions, etc. of the crests 3a, and they can be set as appropriate in consideration of the purpose of use of the bellows 1 and required characteristics. For example, the cross-sectional shape of the peak portion 3a can be a semicircular shape, a triangular shape, or the like, and the shape and dimensions of the plurality of peak portions 3a may be the same, or consist of two or more types. May be.
[0022]
Such a bellows 1 includes a pair of ring-shaped facing surface portions 2A and 2B and a bellows-like wall surface portion 3 that face each other as described above, and has excellent responsiveness, and the facing surface portions 2A and 2B and the bellows-like wall surface portion. Excellent pressure resistance is imparted by the base fabric 10 embedded in 3.
[0023]
In addition, in order to maintain the form of the bellows 1 simply, you may make it attach a round and a reinforcement ring etc. to the trough part 3b along the circumferential direction.
[0024]
The rubber used in the bellows 1 of the present invention as described above may be a conventionally known synthetic rubber or natural rubber, and is not particularly limited. Synthetic rubbers usable in the present invention include, for example, acrylonitrile-butadiene rubber, styrene-butadiene rubber, butadiene rubber, isoprene rubber, propylene-butadiene rubber, acrylonitrile-isoprene rubber, chloroprene rubber, butyl rubber, ethylene-propylene rubber, acrylic Examples thereof include rubber, fluorine rubber, ether-thioether rubber, polysulfide rubber, urethane rubber, and silicon rubber. After adding additives such as a vulcanizing agent and a vulcanization accelerator as described later to such a rubber material as necessary, it is kneaded by a kneading machine, and the resulting rubber mixture is formed into a sheet shape beforehand by a roll. Then, the thickness is adjusted with a calendar to produce a sheet-like molded product (small piece), and then the bellows 1 can be produced by the production method of the present invention described later using this sheet-like molded product.
[0025]
The vulcanizing agent to be used can be appropriately selected according to the rubber used from sulfur, zinc oxide, magnesium oxide, aromatic nitro compound, organic peroxide and the like.
[0026]
Further, as a vulcanization accelerator, a thiazole compound such as 2-mercaptobenzothiazole (MBT), a sulfenamide compound such as N-cyclhexhexyl-2-benzothiazole sulfenamide (CZ), and 2-mercaptothiazoline Thiazoline compounds such as tetramethylthiuram monosulfide (TT), thiuram compounds such as tetraethylthiuram disulfide (TET), dithiocarbamate compounds such as dimethyldithiocarbamate, aldehyde amine compounds such as hexamethylenetetramine, diphenylguanidine, etc. Guanidine compounds, and thiazole compounds such as N, N-diethylcarbamoyl-2-benzothiazyl sulfide can be used.
[0027]
Furthermore, you may contain anti-aging agents, organic fatty acids, such as stearic acid, and fillers, such as carbon black, as needed. Such an additive is preferably contained in an amount of 1 to 150 parts by weight per 100 parts by weight of rubber.
[0028]
As the base fabric 10 used in the bellows 1 of the present invention, a fabric using yarns such as polyamide (6 nylon, 66 nylon, etc.), aramid, polyester, cotton and the like is used for plain weaving, tricot, knitted fabric, karamif, etc. The base fabric and the like formed by adjusting and weaving and immersing this in an adhesive or the like and drying can be exemplified.
[0029]
Production method <br/> then the bellows of the present invention, a method of manufacturing a bellows of the present invention will be described with reference to FIGS. 5-10.
[0030]
(Preform molding process)
In the bellows manufacturing method of the present invention, first, in a preform molding step, a bellows preform made of unvulcanized rubber is molded with a mold. FIG. 5 is a half-sectional view showing an example of a mold used in the preform molding process. In FIG. 5, a preform mold 21 is composed of a core 22, a middle mold 23, an upper mold 24, and a lower mold 25.
[0031]
The core 22 has a disk shape, includes an outer peripheral portion 22a having an inner peripheral surface shape of the bellows 1, and has a concave portion 22b for the bead portion 5 and a groove portion 22c for releasing excess rubber in a ring shape.
[0032]
The middle mold 23 has an inner peripheral part 23 a having the shape of the bellows-like wall surface part 3 of the bellows 1 and can be divided into two or more. In the illustrated example, the upper and lower end portions of the inner peripheral portion 23 a of the middle mold 23 coincide with the apexes of the upper and lower two crest portions constituting the bellows-like wall surface portion 3.
[0033]
The upper mold 24 and the lower mold 25 have a bellows between the outer peripheral portion 22a of the core 22 and the inner peripheral portion 23a of the middle mold 23 in a state where the core 22 and the middle mold 23 are engaged as illustrated. A gap (cavity) for forming the shaped wall portion 3 is formed. Further, the upper mold 24 and the lower mold 25 are formed with a recess 24a for forming a part of the bellows-like wall surface portion 3 and the opposing surface portions 2A and 2B, and a gap (cavity) between the upper die 24 and the lower die 25. Is formed.
[0034]
In such a preform mold 21, the core 22, the middle mold 23, the upper mold 24, and the lower mold 25 are formed in an engaged state as illustrated.
[0035]
The molding of the unvulcanized rubber bellows preform using the preform mold 21 as described above is performed, for example, as shown in FIG. In a state where a plurality of unvulcanized rubber sheet-like molded articles (small pieces) are placed on the outer peripheral surface 22a of the core 22 and the upper surface of the core 22 and the concave portion 25a of the lower mold 25, Each mold member can be engaged and pressurized.
[0036]
At this time, it is necessary to set the temperature and pressure of the mold 21 within a range in which the unvulcanized rubber is not completely vulcanized. Further, pressurization may be performed in a range of about 3 to 90 seconds after several bumps, for example.
[0037]
FIG. 7 is a half-sectional view showing an example of a bellows preform formed in the preform forming process using the mold 21 shown in FIG. 5, and corresponds to FIG.
[0038]
In FIG. 7, the bellows preform 11 made of unvulcanized rubber is provided so that the opposing surface portions 12A and 12B of a pair of opposing ring-shaped flat plates and the outer peripheral edge portion of the opposing surface portion are connected to each other. The bellows-shaped wall surface part 13 which consists of the two peak parts 13a and the two trough parts 13b, and the bead part 15 (thread bead 15a) are provided in the inner peripheral part of opposing surface part 12A, 12B.
[0039]
In addition, when a burr | flash exists in the bellows preform 11 taken out in the state engaged with the core 22 from the metal mold | die 21, this burr | flash is removed. In addition, when the opposed surface portions 12A, 12B, etc. of the molded bellows preform 11 have insufficient rubber thickness, a sheet-like molded product (small piece) of unvulcanized rubber as described above may be added to the corresponding portion. .
[0040]
(Second step)
In the second step of the bellows manufacturing method of the present invention, first, as shown in FIG. 6 (b), the opposing surface portions 12A and 12B of the bellows preform 11 formed in the preform forming step described above and The base fabric 10 is covered so as to cover the bellows-like wall surface portion 13. In addition, the base fabric 10 can also be wound. In FIG. 6B, the base fabric 10 is adhered onto the bellows preform 11 taken out from the mold 21 while being attached to the core 22 in the preform molding step. For example, the base cloth 10 can be attached by using the opening jig 16 capable of expanding the diameter while expanding the cylindrical base cloth 10 in the radial direction (arrow direction) of the bellows-shaped wall surface portion 13. Attach to cover.
[0041]
As shown in FIGS. 4 and 8 to 10, the base fabric 10 is woven so as to have a substantially cylindrical shape, and is positioned at the top portion 3 </ b> A of the peak portion 3 a in the bellows-like wall surface portion 3. The weft yarn of the base fabric 10 is formed and prepared so as to be greater than the elongation of the weft yarn of the base fabric 10 located in the recess 3B of the valley portion 3b.
[0042]
In Fig.8 (a), the substantially cylindrical form of the base fabric 10 is woven so that a cylindrical shape may be exhibited. The length in the warp direction of the cylindrical base fabric 10a shown in FIG. 8 (a) has a length dimension sufficient to cover the bellows-like wall surface portion 13 and the opposing surface portions 12A and 12B of the bellows preform 11. . In order to prepare the base fabric 10 by mass production, for example, as shown in FIG. 8B, a long cylindrical base fabric 10A having a plurality of lengths is woven, and each base fabric 10a is woven. It can be considered that the film is cut at a position corresponding to the length of the film.
[0043]
Further, in FIG. 9, the substantially cylindrical form of the base fabric 10 is formed into ring-shaped facing surface portions 12A and 12B with the cylindrical side surface portion 10b and both cylindrical opening end portions 10c and 10d facing inward. It is woven so as to be provided with shoulder portions 10e, 10f that can be fitted. The length of the side surface portion 10b of the base fabric 10g is long enough to cover the bellows-shaped wall surface portion 13 of the bellows preform 11, and the lengths of both shoulder portions 10e and 10f are The foam 11 has a length dimension sufficient to cover both opposing surface portions 12A and 12B. In order to prepare the base fabric 10 by mass production, for example, as shown in FIG. 9B, a base fabric 10G having an irregular shape having a plurality of length dimensions is woven, and each base fabric 10g is prepared. It can be considered that the film is cut at a position corresponding to the length of the film.
[0044]
Furthermore, in FIG. 10, the substantially cylindrical form of the base fabric 10 is a ridge part 10 h and a valley part 10 i along the form of the ridge part 13 a and the valley part 13 b in the bellows-shaped wall part 13 of the bellows preform 11. The cylindrical opening end portions 10j and 10k are woven so as to have shoulder portions 10l and 10m so that they face the ring-shaped facing surface portions 12A and 12B with the inner ends facing inward. Accordingly, the base fabric 10n has a length dimension sufficient to cover the bellows-shaped wall surface portion 13 and the opposing surface portions 12A and 12B of the bellows preform 11 over the entire curved surface. In the base fabric preparation step in the present embodiment, the base fabric 10n has a bellows shape, and thus is woven as a single base fabric. However, the present invention is not limited to this, and a long bellows having a plurality of length dimensions is not limited thereto. The base fabric may be woven and cut at a position corresponding to the length of each base fabric 10n.
[0045]
As described above, the base fabrics 10a (FIG. 8), 10g (FIG. 9), and 10n (FIG. 10) are woven so as to have a substantially cylindrical shape, and the top portion 3A of the peak portion 3a in the bellows-like wall surface portion 3 is obtained. 6 (c) because the elongation of the weft yarn of the base fabric 10 located in the region is larger than the elongation of the weft yarn of the base fabric 10 located in the recess 3B of the valley portion 3b. As shown in the figure, the base fabric 10 can be surely placed along the peak portion 13a and the valley portion 13b of the bellows-shaped wall portion 13 of the bellows preform 11. Further, when the base fabric 10 is bonded to the facing surface portions 12A, 12B, etc. of the bellows preform 11, it can be bonded using the above-mentioned small pieces of unvulcanized rubber material. After such application of the base fabric 10 is completed, the excess base fabric is removed, and further, the base fabric 10 is pressed against the bellows preform 11 so as not to cause wrinkles.
[0046]
Next, in the second step, the bellows preform 11 around which the base fabric 10 is wound is vulcanized. As shown in FIG. 6 (d), the final molding die 41 is composed of the core 22, the middle die 43, the upper die 44, and the lower die 45.
[0047]
The core 22 is used in common with the core 22 constituting the preform molding die 21 used in the above-described preform molding step.
[0048]
The middle mold 43 has an inner peripheral part 43a having the shape of the bellows-like wall surface part 3 of the bellows 1, and can be divided into two or more. In the illustrated example, the upper and lower end portions of the inner peripheral portion 43 a of the middle mold 43 are respectively coincident with the apexes of the two upper and lower peaks constituting the bellows-like wall surface portion 3.
[0049]
Molding of the bellows 1 using such a final molding die 41 includes a core 22, around which the bellows preform 11 to which the base fabric 10 is attached as described above, a middle mold 43, and an upper mold. 44 and the lower mold 45 are engaged, pressurized and heated. The pressurization can be performed, for example, after bumping several times, and the temperature and time during vulcanization can be appropriately set according to the rubber material used.
[0050]
After the final molding using such a mold 41 is performed, the bellows 1 is taken out from the mold 41, and if there is a burr, the burr is removed to complete the manufacture of the bellows 1.
[0051]
In the bellows manufacturing method of the present invention described above, the core 22 of the mold 21 used in the preform molding process is shared with the core 22 of the mold 41 used in the second process. The invention is not limited to this. For example, the base fabric 10 may be mounted after the bellows preform 11 molded in the preform molding process is mounted on the core dedicated to the mold 41.
[0052]
【The invention's effect】
As described above in detail, according to the present invention, the base fabric located on the bellows-like wall surface portion of the bellows preform is woven so as to have a substantially cylindrical shape, and the top of the peak portion in the bellows-like wall surface portion. Since the weft of the base fabric located in the base fabric is formed so as to be larger than the elongation of the weft of the base fabric located in the depression of the valley, wrinkles (even if it is relatively thin) The bellows excellent in pressure resistance can be manufactured with a very high yield.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embodiment of a bellows of the present invention.
FIG. 2 is a plan view of the bellows shown in FIG.
FIG. 3 is a half-sectional view taken along the line AA in FIG. 2;
FIG. 4 is a schematic diagram for explaining a weaving state of a base fabric used in the present embodiment.
FIG. 5 is a half-sectional view showing an example of a mold used in a preform molding step of the bellows manufacturing method of the present invention.
6A and 6B are diagrams illustrating a method for manufacturing a bellows according to the present invention, in which FIG. 6A is a half-sectional view illustrating a situation in which a bellows preform is molded in a preform molding process, and FIG. It is a half piece sectional view showing the situation where a base cloth is attached, (c) is a half piece sectional view showing a bellows preform which covered a base cloth, and (d) is a half piece sectional view showing a vulcanization molding process. .
7 is a view showing a bellows preform formed by the preform forming step of the bellows manufacturing method of the present invention, and corresponds to FIG. 3. FIG.
FIG. 8A is a perspective view showing a cylindrical base fabric, and FIG. 8B is a perspective view showing a long base fabric in which a cylindrical base fabric is continuously woven in consideration of productivity. It is.
FIG. 9A is a schematic view showing an irregularly shaped base fabric, and FIG. 9B is a perspective view showing a long base fabric in which the irregularly shaped base fabric is continuously woven in consideration of productivity. It is.
FIG. 10 is a schematic view showing a bellows-shaped base fabric.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Bellows 2A, 2B ... Opposite surface part 3 ... Bellows-like wall surface part 3a ... Mountain part 3b ... Valley part 4 ... Opening part 5 ... Bead part 10 ... Base cloth 11 ... Bellows preform 21, 31, 41 ... Mold 22, 32 ... Core 23, 33, 43 ... Middle type 24, 34, 44 ... Upper type 25, 35, 45 ... Lower type

Claims (6)

A bellows-like wall surface having a pair of ring-shaped facing surface portions arranged so as to face each other, and two or more peak portions and one or more valley portions provided so as to connect the outer peripheral edge portions of the facing surface portions to each other A rubber bellows with a base fabric comprising a base fabric integrally embedded in the portion and the opposing surface portion and the bellows-like wall surface portion,
The stretchability of the weft in the bellows circumferential direction of the base fabric disposed at the top of the peak is set to be greater than the stretchability of the weft in the bellows circumferential direction of the base fabric disposed in the recess of the valley. Bellows characterized by that. In the central longitudinal section of the bellows, the vertical axis is a line that connects the depressions of the valleys in the axial direction, and the vertical axis is a line that goes to the top of the peak in the direction perpendicular to the vertical axis. The base fabric arranged within an angle range of ± 30 ° from the center of the measurement reference position to the top of the mountain, with the intersection with the horizontal axis being the center of the angle measurement reference position and the horizontal axis being the 0 ° line. The bellows according to claim 1, wherein the stretchability of the weft yarn in the circumferential direction of the bellows is set to be larger than the stretchability of the weft yarn in the circumferential direction of the bellows of the base fabric disposed in the recessed portion of the valley portion. A bellows-like wall surface having a pair of ring-shaped facing surface portions arranged so as to face each other, and two or more peak portions and one or more valley portions provided so as to connect the outer peripheral edge portions of the facing surface portions to each other A preform molding step of molding a bellows preform made of unvulcanized rubber with a mold,
The crests bellows circumferential direction of the weft of the stretchable base fabric located at the top of, taken into consideration so as to be larger than the weft of the stretchable bellows circumferential direction of the base cloth positioned recess of the valley Preparing a base fabric that is a formed base fabric and woven so as to have a substantially cylindrical shape;
A step of depositing a base fabric having the substantially cylindrical form on a bellows preform made of unvulcanized rubber formed by the preform molding step;
A method for producing a bellows, comprising: a vulcanization molding step in which the adhered base fabric is pressed into a bellows preform made of unvulcanized rubber with a mold and vulcanized.   The method for manufacturing a bellows according to claim 3, wherein the substantially cylindrical form of the base fabric is cylindrical.   The substantially cylindrical form of the base fabric includes a cylindrical side surface portion and a shoulder portion that extends along both the ring-shaped opposing surface portions with both cylindrical opening end portions facing inward. 3. A method for producing a bellows according to 3.   The manufacturing method of the bellows of Claim 3 with which the substantially cylindrical form of the said base fabric is provided with the peak part and trough part along the form of the said bellows-like wall surface part.

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