JP2008168492A - Method of manufacturing rubber-made tube, method of manufacturing air spring, molding apparatus for unvulcanized rubber tube and air spring - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a rubber-made tube which enables orientation of short fibers in the direction along the plane passing the central axis, even for tubes of large diameters or indefinite diameters, e.g. the drum-shaped or the Japanese-hand-drum-shaped. <P>SOLUTION: An unvulcanized rubber tube 9 is extruded around a guide rod 8 to orient short fibers 4 contained in the tube in the direction of the central axis of the tube. When being extruded, the unvulcanized rubber tube 9 is cut spirally with a cutter 11 running around the tube to form an unvulcanized tape 10. At the same time, a forming drum 12, while moved in the extruding direction of the unvulcanized rubber tube 9, is made to rotate and run around the unvulcanized rubber tube 9 at the same rpm of the cutter 11. The unvulcanized rubber tape 10 is wound around the forming drum 12 to form an unvulcanized rubber tube 3. The short fibers 4 are oriented along the plane including the central axis of the unvulcanized rubber tube 3 and along the surface of the unvulcanized rubber tube 3. Then, the unvulcanized rubber tube 3 is vulcanized and formed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a rubber cylinder containing short fibers, a method for producing an air spring provided with the rubber cylinder as a diaphragm, and an unvulcanized rubber cylinder before vulcanization molding to a rubber cylinder. The present invention relates to a molding device and an air spring including a cylindrical diaphragm made of rubber containing short fibers.

  In general, rubber cylinders such as air spring diaphragms, rubber pipe joints, tires, rubber hoses and the like are manufactured by vulcanization molding of an unvulcanized rubber cylinder formed by molding unvulcanized rubber into a cylinder. For molding unvulcanized rubber cylinders, the unvulcanized rubber is extruded into a tube shape and placed on the molding drum, the unvulcanized rubber is directly coated on the molding drum by the crosshead method, and the molding drum is unvulcanized. A method of winding a rubber tape in a spiral shape is used.

  Among these molding methods, the method of extruding unvulcanized rubber into a tube shape and the crosshead method are for molding unvulcanized rubber cylinders such as rubber hoses that have a relatively small diameter and a constant diameter along the central axis direction. Used to mold relatively large-diameter unvulcanized rubber cylinders such as air spring diaphragms and tires, and drum-shaped and drum-shaped unvulcanized rubber cylinders. The method of wrapping around is adopted.

  Moreover, for the purpose of improving physical properties such as the rigidity, strength, and wear resistance of rubber, a short tube may be contained in a rubber cylinder (for example, Patent Document 1). A rubber cylinder containing such short fibers can be produced by adding short fibers to the unvulcanized rubber that forms the unvulcanized rubber cylinder.

Furthermore, air springs and the like are fastened to other members with fasteners and sealed with the elastic force of the end rubber compressed by fastening. It is expected that the sealing performance will be improved by increasing. Specifically, the end rubber that has been compressed in the thickness direction by fastening tends to stretch along a plane that passes through the central axis of the rubber cylinder. Can be increased.
JP 2000-297533 A

  By the way, the short fiber contained in the rubber contributes to the rigidity and strength in the orientation direction, but does not contribute to the rigidity and strength in the direction orthogonal to the orientation direction, and therefore follows a plane passing through the central axis of the rubber cylinder. In order to suppress the elongation of the rubber in the direction, it is necessary to orient the short fibers in the direction of the elongation. Therefore, when an unvulcanized rubber tape is wound in a spiral shape to form an unvulcanized rubber cylinder, the short fibers 102 are oriented in the tape width direction of the unvulcanized rubber tape 101 as shown in FIG. There is a need.

  However, when the unvulcanized rubber tape is formed by calendaring or extrusion, the short fibers are oriented in the tape length direction, which is the drawing direction or the extrusion direction. Therefore, the unvulcanized rubber tape is formed by winding such an unvulcanized rubber tape. In the rubber cylinder, short fibers are oriented in the circumferential direction without being along a plane passing through the central axis.

  On the other hand, short fibers can be oriented in the direction of the central axis by adopting a method of extruding unvulcanized rubber into a tube shape or a cross head method. It cannot be used for molding unvulcanized rubber cylinders such as air spring diaphragms and tires having a diameter and an indefinite diameter.

  On the other hand, as shown in FIG. 5B, the unvulcanized rubber tape 103 in which the short fibers 102 are oriented in the tape length direction formed by a calendar or the like is cut intermittently, the direction thereof is changed, and the tape is again formed. A method of forming the unvulcanized rubber tape 101 in which the short fibers 102 are oriented in the tape width direction by arranging them in a tape shape can be considered, but this method requires two steps to form the unvulcanized rubber tape 101, and Since the unvulcanized rubber tape 103 is cut intermittently, the molding of the unvulcanized rubber cylinder is also intermittent.

  Further, as shown in FIG. 5C, an unvulcanized rubber tube 104 is extruded so that the short fibers 102 are oriented in the central axis direction, and this is cut into a spiral shape so that the short fibers 102 are formed in the tape width direction. Although a method of forming the oriented unvulcanized rubber tape 101 is also conceivable, as shown in FIG. 5C, this method twists the unvulcanized rubber tape 101 when it is pulled out from the unvulcanized rubber tube 104. .

  The present invention relates to a method for producing a rubber cylinder having a large diameter or an indefinite diameter such as a drum shape or a drum shape and capable of orienting short fibers in a direction along a plane passing through the central axis, and the rubber cylinder Of an air spring provided with a diaphragm as a diaphragm, an apparatus for forming an unvulcanized rubber cylinder before vulcanization molding into a rubber cylinder, and an air spring provided with a cylindrical diaphragm made of rubber containing short fibers For the purpose of provision.

  In order to achieve the above object, the present invention provides a method for producing a rubber cylinder containing short fibers. Specifically, first, an unvulcanized rubber tube containing short fibers is extruded to form an unvulcanized rubber tube in which the short fibers are oriented in the tube central axis direction. Further, the unvulcanized rubber tube is cut into a spiral shape to form an unvulcanized rubber tape containing short fibers, and the molding drum is rotated around its central axis while rotating around the unvulcanized rubber tube. By rotating the unvulcanized rubber tape around the molding drum in a spiral manner to form the unvulcanized rubber cylinder, the short fiber is flat and includes the central axis of the unvulcanized rubber cylinder and the unvulcanized rubber cylinder. Then, the unvulcanized rubber cylinder is vulcanized and molded.

  According to the above configuration, since the unvulcanized rubber tape is spirally wound around the molding drum to mold the unvulcanized rubber cylinder, the rubber cylinder body having a large diameter or an indefinite diameter such as a drum shape or a drum shape is used. Even if it exists, the unvulcanized rubber cylinder can be molded easily and accurately. In addition, by cutting the unvulcanized rubber tube into a spiral shape, an unvulcanized rubber tape in which short fibers are oriented in the tape width direction is formed, so that the flat surface including the central axis of the rubber cylinder and the unvulcanized rubber cylinder It is possible to orient short fibers in a direction along the surface.

  Further, since the molding drum circulates around the unvulcanized rubber tube, the unvulcanized rubber tape can be taken out from the unvulcanized rubber tube without being twisted. Moreover, since the molding drum rotates, even if the diameters of the unvulcanized rubber cylinder and the unvulcanized rubber tube are different, the unvulcanized rubber tape is taken out from the unvulcanized rubber cylinder and wound around the molding drum. The length can be matched.

  Here, the short fiber is not limited as long as it is oriented to the extrusion direction by extruding unvulcanized rubber containing it to increase the rigidity and strength of the rubber, and its material and dimensions are limited. However, in consideration of its rigidity, strength and dispersibility in unvulcanized rubber, nylon short fibers and aramid short fibers having an average fiber diameter of 1 μm to 20 μm and an average fiber length of 3 mm to 20 mm are used. It can be illustrated. Moreover, as a compounding quantity of the short fiber to the unvulcanized rubber, the short fiber is added in an amount of 0.5 to 5 parts by weight with respect to 100 parts by weight of the unvulcanized rubber in consideration of handling properties and rubber properties after vulcanization. It is preferable to mix by weight.

  Further, the rubber cylinder may be a vulcanized molding of only an unvulcanized rubber cylinder formed by spirally winding an unvulcanized rubber tape. Further, a reinforcing layer may be provided as rubber or outer surface rubber.

  That is, an unvulcanized rubber cylinder formed by wrapping and molding an unvulcanized rubber tape spirally around a molding drum is used as an inner surface rubber, and a reinforcing layer and an outer surface rubber are arranged on the outer side thereof, and then an inner surface rubber as an unvulcanized rubber cylinder, A laminate of the reinforcing layer and the outer rubber can be vulcanized. Alternatively, an inner rubber and a reinforcing layer are arranged outside the molding drum, and an unvulcanized rubber cylinder formed by winding an unvulcanized rubber tape in a spiral shape on the outer side is used as an outer rubber. It is also possible to vulcanize and mold an outer rubber laminate as a vulcanized rubber cylinder.

  The extrusion molding of the unvulcanized rubber tube, the cutting into the unvulcanized rubber tape, and the winding of the unvulcanized rubber tape around the molding drum can be performed separately, but these may be performed simultaneously.

  Specifically, by extruding the unvulcanized rubber tube around the guide rod and in the central axis direction of the guide rod, by rotating the cutter around the guide rod around the guide rod, The unvulcanized rubber tube is cut into a spiral shape to form an unvulcanized rubber tape. Simultaneously with the formation of the unvulcanized rubber tape, the molding drum is moved in the extrusion direction of the unvulcanized rubber tube, and the molding drum is rotated and rotated at the same rotational speed as that of the cutter. Wrap the rubber rubber tape in a spiral.

  According to this configuration, the unvulcanized rubber tube is extruded, cut into the unvulcanized rubber tape, and the unvulcanized rubber tape is wound around the molding drum at the same time. Automation can be achieved. Further, since the unvulcanized rubber tube is cut in a spiral shape while being extruded, the length of the guide rod can be set short.

  By the way, even if the tape width of the unvulcanized rubber tape and the orientation direction of the short fiber with respect to the tape width direction are the same, if the diameter of the unvulcanized rubber cylinder to be wound and molded is different, the short width relative to the central axis direction is reduced. The orientation direction of the fibers is also different. On the other hand, when molding an unvulcanized rubber cylinder of an arbitrary diameter, in order to set the orientation direction of the short fiber with respect to the central axis to a desired direction, the unvulcanized rubber tube extrusion speed and the rotation of the cutter are rotated. The width of the unvulcanized rubber tape may be adjusted by adjusting at least one of the numbers.

  That is, in order to set the orientation direction of the short fibers with respect to the central axis of the unvulcanized rubber cylinder to a desired direction, the tape width of the unvulcanized rubber tape or the orientation direction of the short fibers with respect to the tape width direction may be adjusted. Moreover, by adjusting the width of the tape cut out from the unvulcanized rubber tube, the orientation direction of the short fibers relative to the tape width direction can be set to a desired direction, so by adjusting the width of the unvulcanized rubber tape The orientation direction of the short fibers can be set to a desired direction.

  Furthermore, the unvulcanized rubber tape cut out spirally from the unvulcanized rubber tube, the orientation direction of the short fiber changes corresponding to the diameter of the unvulcanized rubber tube, but by adjusting the tape width, the tape width Since the orientation direction of the short fibers with respect to the direction can be set to a desired direction, a desired unvulcanized rubber tape can be cut out from an unvulcanized rubber tube having an arbitrary diameter.

  In addition, in order to mold an unvulcanized rubber cylinder whose inner diameter changes along the central axis direction, a molding drum whose outer diameter changes along the central axis direction is used, and an unvulcanized rubber corresponding to the diameter is used. What is necessary is just to change the tape width of a rubber tape. That is, while adjusting the tape width by adjusting at least one of the extrusion speed of the unvulcanized rubber tube, the rotational speed of the cutter rotation, and the position of the cutter in the central axis direction of the guide rod, the unvulcanized rubber What is necessary is just to change the internal diameter along the center axis direction of a pipe | tube.

  By supporting the molding drum in a cantilevered manner, the molding drum can be supported without causing the support member to interfere with the guide rod, and the length (L) and inner diameter (D) of the unvulcanized rubber cylinder in the central axis direction. ) And the ratio (L / D) to 10 or less, the bending accuracy of the molding drum can be suppressed and the molding accuracy of the unvulcanized rubber cylinder can be increased.

  When unvulcanized rubber tape is wound spirally around the molding drum, the thickness of the unvulcanized rubber cylinder to be molded can be adjusted by stacking the side edges of the unvulcanized rubber tape on the previously wound portion. For example, an unvulcanized rubber cylinder having a desired thickness can be molded without changing the thickness of the unvulcanized rubber tube during extrusion molding.

  Moreover, an air spring can be manufactured by using the rubber cylinder manufactured by the above method as a diaphragm and attaching a fastening fitting to at least one end of the diaphragm. In addition to the air spring, the above manufacturing method can also manufacture rubber pipe joints, tires, rubber hoses, and the like.

  The present invention also provides an apparatus for molding an unvulcanized rubber cylinder before vulcanization molding into a rubber cylinder. Specifically, a die, a guide rod that penetrates the die hole from the inside of the die and protrudes in the extrusion direction, and supplies the unvulcanized rubber to the die while applying pressure to the periphery of the die hole and the gap between the guide rods An extruder that extrudes an unvulcanized rubber tube around the guide rod, a cutter that circulates around the guide rod and spirally cuts the unvulcanized rubber tube to form an unvulcanized rubber tape, And a molding drum for spirally winding a vulcanized rubber tape to form an unvulcanized rubber cylinder. Furthermore, the molding drum moves in the extrusion direction and rotates around the guide rod at the same rotational speed as the cutter while rotating around its central axis as a rotation axis, thereby spiraling the unvulcanized rubber tape around it. Wrapping.

  According to this configuration, similarly to the above-described method for manufacturing a rubber cylinder, an unvulcanized rubber cylinder can be easily and easily formed even in a rubber cylinder having a large diameter or an indefinite diameter such as a drum shape or a drum shape. It can be molded accurately. The extruder may be a straight extruder having a head composed of a spindle and a die, or a crosshead extruder in which the head and the screw intersect.

  In addition, if the position of the cutter in the central axis direction of the guide rod can be adjusted, the tape width of the unvulcanized rubber tape can be changed without changing the extrusion speed of the unvulcanized rubber tube and the rotation speed of the cutter and molding drum. Therefore, it is possible to facilitate molding of an uncured unvulcanized rubber cylinder.

  This molding device can be used for molding ordinary unvulcanized rubber cylinders that do not contain short fibers, but if an unvulcanized rubber cylinder is molded from unvulcanized rubber containing short fibers, a rubber cylinder The short fiber can be oriented in the direction along the plane including the central axis of the rubber cylinder and the surface of the unvulcanized rubber cylinder while containing the short fiber in the body, and the method for producing the rubber cylinder, The same effect can be obtained.

  In the present invention, a fastener is attached to at least one end of a cylindrical diaphragm made of rubber containing short fibers, and the short fibers extend in a direction along the plane including the central axis of the diaphragm and the surface of the diaphragm. An air spring characterized by being oriented is provided.

  According to this configuration, since the short fibers are oriented in the direction along the plane including the central axis of the diaphragm and the surface of the diaphragm, the rigidity of the end rubber against compression in the thickness direction by the fastener can be increased. Further, the inner pressure sealing performance of the diaphragm can be improved, and the air spring can be reduced in size by high pressure and large displacement.

  As described above, according to the present invention, the unvulcanized rubber tape formed by spirally cutting the unvulcanized rubber tube is wound around the molding drum by rotating the molding drum around the unvulcanized rubber tube. It is possible to easily and accurately mold an unvulcanized rubber cylinder of a rubber cylinder having a large diameter or an indefinite diameter such as a drum shape or a drum shape.

  Moreover, since the short fibers contained in the unvulcanized rubber can be oriented in the direction along the plane passing through the central axis of the rubber cylinder, the rigidity of the end rubber can be increased, thereby The internal pressure sealing performance of the air spring diaphragm can be enhanced.

  BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out a rubber cylinder manufacturing method, an air spring manufacturing method, an unvulcanized rubber cylinder molding apparatus, and an air spring according to the present invention will be described below with reference to the drawings.

  First, the configuration of an unvulcanized rubber cylinder molding apparatus will be described. FIG. 1 is a schematic view showing a molding apparatus for an unvulcanized rubber cylinder according to the present invention.

  For example, the molding apparatus 1 molds the unvulcanized rubber cylinder 3 before vulcanization molding into a rubber cylinder 2 as a diaphragm of an air spring, for example, so that the unvulcanized rubber cylinder 3 contains short fibers 4. Extruder 6 that feeds unvulcanized rubber 5 containing short fibers 4 to a die 7 attached to a head 6a at the tip while pressurizing, and a die hole 7a of the die 7 in the extrusion direction A guide rod 8 projecting in the direction of the rod, a cutter 11 for forming an unvulcanized rubber tape 10 by cutting an unvulcanized rubber tube 9 extruded around the guide rod 8 into a spiral shape, and a spiral of the unvulcanized rubber tape 10 And a molding drum 12 for molding the unvulcanized rubber cylinder 3 by being wound in a shape.

  The extruder 6 has a cylindrical head 6a provided at the tip of a tubular extruder body 6b, and the unvulcanized rubber 5 is directed toward the head 6a by rotating a screw 6c built in the extruder body 6b. To be pumped. Thereby, the unvulcanized rubber 5 is extruded from the gap between the inner peripheral edge of the die hole 7a of the die 7 attached to the head 6a and the outer peripheral surface of the guide rod 8 penetrating the die hole 7a, and protrudes in the extrusion direction. An unvulcanized rubber tube 9 is extruded around the guide rod 8 to be performed.

  The die 7 has a plate shape having a die hole 7a in the center thereof, and is bolted to one end in the central axis direction of the head 6a so as to cover the center hole of the head 6a from one side (extrusion direction side). The die hole 7a is set to a size for extruding the unvulcanized rubber tube 9 to a desired outer diameter.

  The guide rod 8 is housed in the central hole of the head 6a, and the tip of the guide rod 8 penetrates the die hole 7a and protrudes in the extrusion direction, and the base end is bolted to the other end in the central axis direction of the head 6a. The center hole is covered from the other side. The outer diameter of the guide rod 8 is, for example, about φ100 mm, and is set to a size for extruding the unvulcanized rubber tube 9 to a desired inner diameter. A portion of the guide bar 8 that is housed in the head 6a is set to have a length in the central axis direction longer than the outer diameter so that the unvulcanized rubber 5 to be pushed out extends over the entire circumference. Moreover, the site | part which protrudes in an extrusion direction is formed in the taper shape slightly thin as the front-end | tip so that it may be easy to extrude the unvulcanized rubber tube 9. FIG.

  The cutter 11 is supported by a cutter orbiting device 13 arranged so as to surround the guide rod 8, and the cutter 11 rotates around the guide rod 8 so that the cutter 11 circulates around the guide rod 8. The vulcanized rubber tube 9 is cut into a spiral shape. The cutter 11 is adjustable in the position of the guide bar 8 in the central axis direction, thereby adjusting the tape width of the unvulcanized rubber tape 10 formed by spirally cutting the unvulcanized rubber tube 9. It has become.

  The molding drum 12 is arranged in parallel with the guide rod 8, and one side end thereof is cantilevered by a molding drum orbiting device 14 arranged on one side of the tip of the guide rod 8. The apparatus 14 rotates in the circumferential direction at the same rotational speed as the cutter rotating apparatus 13 while moving in the extrusion direction.

  As a result, the molding drum 12 circulates around the guide rod 8 at the same rotational speed as that of the cutter 11 while moving in the extrusion direction, and the unvulcanized rubber tape 10 is wound around the molding drum 12 in a spiral shape. The rubber rubber cylinder 3 is molded. Further, the molding drum 12 rotates with its central axis as the rotation axis, so that the cutting speed of the unvulcanized rubber tape 10 from the unvulcanized rubber tube 9 and the winding speed around the molding drum 12 are made to coincide. ing.

  The outer diameter of the molding drum 12 is, for example, about φ142 mm, and the length in the central axis direction of the molding drum 12 is not yet up to a ratio (L / D) of the central axis length (L) to the inner diameter (D) of up to 10. The length required for molding the vulcanized rubber cylinder 4 is set. Accordingly, the bending accuracy of the molding drum 12 that circulates around the guide rod 8 while being cantilevered is sufficiently suppressed, and the molding accuracy of the unvulcanized rubber cylinder 4 is increased.

  Next, a method for manufacturing a rubber cylinder will be described. First, the unvulcanized rubber 5 containing the short fibers 4 is pressurized by the extruder 6 and extruded from the die hole 7 a along the central axis direction of the guide rod 8, so that the short fibers 4 are formed around the guide rod 8. An unvulcanized rubber tube 9 oriented in the tube central axis direction, that is, the extrusion direction is extruded. As this extrusion molding, for example, an unvulcanized rubber tube 9 having an extrusion speed of about 2 m / min and a thickness of about 1.5 mm can be extruded. Here, the short fibers 4 contained in the unvulcanized rubber 5 are nylon short fibers having an average fiber diameter of 1 μm to 20 μm and an average fiber length of 3 mm to 20 mm, for example, and are oriented in the extrusion direction of the unvulcanized rubber 5. To do.

  Further, the unvulcanized rubber tube 9 is spirally cut by rotating the cutter 11 around the guide rod 8 while continuously extruding the unvulcanized rubber tube 9 around the guide rod 8. For example, the unvulcanized rubber tape 10 containing the short fibers 4 with a tape width of about 39 mm is formed. At this time, the short fibers 4 are oriented in a direction slightly inclined with respect to the tape width direction of the unvulcanized rubber tape 10. The inclination angle in the orientation direction of the short fibers 4 increases as the tape width increases, and approaches 0 ° as the tape width decreases. Therefore, the tape width may be set so that a desired inclination angle is obtained. That is, the width of the unvulcanized rubber tape 10 may be adjusted by adjusting at least one of the extrusion speed of the unvulcanized rubber tube 9 and the rotational speed of the cutter 11.

  Further, simultaneously with the extrusion molding of the unvulcanized rubber tube 9 and the formation of the unvulcanized rubber tape 10, the molding drum 12 is moved in the extrusion direction at the same speed as the extrusion speed of the unvulcanized rubber tube 9, The shaft is rotated around the unvulcanized rubber tube 9 at the same rotational speed as that of the cutter 11 while rotating around the rotation axis. As a result, the unvulcanized rubber tape 10 is wound around the molding drum 12 in a spiral manner, and the side edges of the unvulcanized rubber tape 10 are joined in order to mold the unvulcanized rubber cylinder 3. At this time, the short fibers 4 are oriented in a direction substantially along the plane including the central axis of the unvulcanized rubber cylinder 3 and the surface of the unvulcanized rubber cylinder 3.

  Here, for example, when the molding drum 12 has a complicated shape such as a truncated cone, a drum shape, or a drum shape, and the unvulcanized rubber cylinder 3 having these shapes is molded, the unvulcanized rubber cylinder The short fibers 4 are preferably oriented in a substantially constant direction by changing the tape width of the unvulcanized rubber tape 10 in correspondence with the change in the inner diameter along the direction of the central axis 3. Specifically, the unvulcanized rubber tape is adjusted by adjusting at least one of the extrusion speed of the unvulcanized rubber tube 9, the rotational speed of the cutter 11, and the position of the cutter 11 in the central axis direction of the guide bar 8. While changing the tape width of 10, the rotational speed and movement speed of the molding drum 12 are adjusted.

  Next, the unvulcanized rubber cylinder 3 is used as an inner surface unvulcanized rubber, and a reinforcing layer and an outer surface unvulcanized rubber are arranged on the outer side thereof. Thereafter, the inner surface unvulcanized rubber as the unvulcanized rubber cylinder 3, the reinforcing layer, and The rubber cylinder 2 is obtained by vulcanizing and molding the laminate of the outer surface unvulcanized rubber.

  Furthermore, an air spring can be manufactured by using the rubber cylinder 2 manufactured by the above method as a diaphragm and attaching a fastening fitting to at least one end thereof. In this air spring, the diaphragm is made of rubber containing the short fibers 4, and the short fibers 4 are oriented in a direction along the plane including the central axis of the diaphragm and the surface of the diaphragm. Thereby, the rigidity of the rubber against compression in the thickness direction by the fastening fitting attached to the end portion of the diaphragm is increased, and the sealing performance against the internal air pressure is improved.

  Here, the influence of the orientation direction of the short fibers on the rigidity of the rubber will be described. FIG. 2 is a graph showing the relationship between the elongation and tensile stress of rubber containing short fibers oriented in a certain direction. In FIG. 2, A shows the relationship when the rubber is pulled in the orientation direction of the short fibers, and B shows the relationship when the rubber is pulled in a direction perpendicular to the orientation direction of the short fibers.

  As shown in FIG. 2, the short fibers 4 regulate the elongation in the orientation direction, so that in the range of the tensile rate of 15% to 40%, which is the tensile rate of normal rubber products, in the orientation direction of the short fibers 4. It can be seen that, when pulled, the tensile stress is 2.5 to 3 times the same elongation (%) than when pulled in the direction perpendicular to the orientation direction.

  Thus, since the short fibers 4 regulate the elongation in the orientation direction, by orienting the short fibers 4 in a direction along the plane including the central axis of the diaphragm and the surface of the diaphragm, that is, as shown in FIG. In the rubber folded portion at the end of the diaphragm, the short fibers 4 are oriented radially, so that the elongation in the orientation direction (arrow direction in FIG. 3) due to compression with the fastening metal is restricted, and the rigidity of the end rubber is reduced. This improves the sealing performance against the internal air pressure.

  According to the above configuration, the unvulcanized rubber tape 10 is spirally wound around the molding drum 12 and the unvulcanized rubber cylinder 3 is molded. Therefore, by appropriately setting the shape of the molding drum 12, a large diameter of about 200 mm or more is obtained. Alternatively, an unvulcanized rubber cylinder 3 having an indefinite diameter such as a truncated cone shape, a drum shape, or a drum shape can also be formed. Thereby, even the rubber cylinder 2 having a large diameter and a complicated shape, such as a diaphragm of an air spring, can be accurately manufactured.

  In other words, for example, the method of directly covering an extruded unvulcanized rubber tube on a molding drum cannot be extruded to a size exceeding φ200 mm practically, and when it is extruded into a long tube shape, it is molded. Dimensional variation is likely to occur when placed on the drum. On the other hand, the molding by winding the unvulcanized rubber tape 10 does not change the dimensions when forming the unvulcanized rubber tape 10 or winding it around the molding drum.

  Moreover, even when molding a large-diameter unvulcanized rubber cylinder 3, as in direct coating with a crosshead method, the molding does not become difficult and the equipment cost does not increase extremely, A thin wall having a thickness of about several mm can be molded.

  Moreover, the molding by winding the unvulcanized rubber tape 10 does not increase the material loss as in the case of the tube system or the cross head direct coating even when the short unvulcanized rubber cylinder 3 is molded.

  Furthermore, since the unvulcanized rubber tube 9 formed by extruding the unvulcanized rubber 5 containing the short fibers 4 is spirally cut to form the unvulcanized rubber tape 10, almost the tape of the unvulcanized rubber tape 10 is obtained. The short fibers 4 can be oriented in the width direction. Thereby, the short fibers 4 can be oriented in the direction along the plane including the central axis of the rubber cylinder 2 and the surface of the rubber cylinder 2, and the rigidity of the end rubber against the compression in the thickness direction by the fasteners. The internal pressure sealing performance can be enhanced. In addition, there is little decrease in the sealing pressure due to repeated deformation, and high-pressure sealing can be performed over a long period of time. For example, the air spring can be reduced in size by high pressure and large displacement.

  Further, since the unvulcanized rubber tube 9 is extruded and left in a hot state immediately after being cut, an unvulcanized rubber tape 10 is formed and wound around the molding drum 12. It is possible to strongly bond each other.

  A single molding apparatus 1 can form unvulcanized rubber tapes 10 of various thicknesses and widths, and the extruder 6 simply extends the length of the guide bar 8 as compared with the conventional one. Conventionally used extruders can be used almost as they are.

  In addition, this invention is not limited to said embodiment, A change can be suitably added within the scope of the present invention. For example, as shown in FIG. 4, the molding drum 12 can be arranged to be inclined with respect to the guide bar 8 instead of being arranged in parallel with the guide bar 8, whereby the unvulcanized rubber tape 10 is wound. The angle may be adjusted.

  Further, when the unvulcanized rubber tape 10 is spirally wound around the molding drum 12, the unvulcanized rubber cylinder 3 to be molded is overlapped with the side edge of the winding portion of the unvulcanized rubber tape 10 over the previously wound portion. You can also adjust the thickness.

  The molding apparatus 1 can be suitably used for molding an unvulcanized rubber cylinder 3 containing short fibers 4, but may be used for molding an unvulcanized rubber cylinder not containing short fibers 4. The rubber cylinder 2 to be manufactured may be not only a diaphragm of an air spring but also a rubber pipe joint, a tire, a rubber hose, or the like.

  The unvulcanized rubber cylinder 3 is an inner unvulcanized rubber, a reinforcing layer and an outer unvulcanized rubber are arranged on the outer side, and these laminates are vulcanized to form a rubber cylinder 2. It is not limited to. That is, only the unvulcanized rubber cylinder 3 may be vulcanized and molded into the rubber cylinder 2, or the unvulcanized rubber cylinder 3 as the outer unvulcanized rubber on the outside of the inner surface unvulcanized rubber and the reinforcing layer. These layers may be vulcanized and molded to form a rubber cylinder 2, and both the inner surface unvulcanized rubber and the outer surface unvulcanized rubber may be the unvulcanized rubber cylinder 3.

The schematic diagram which shows the molding apparatus of the unvulcanized rubber cylinder which concerns on this invention Diagram showing the relationship between the elongation and tensile stress of rubber containing short fibers oriented in a certain direction Schematic showing the diaphragm end where short fibers are oriented radially The schematic diagram which shows another form of the shaping | molding apparatus of the unvulcanized rubber cylinder which concerns on this invention Diagram showing the conventional method for forming unvulcanized rubber tape

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Molding apparatus 2 Rubber cylinder 3 Unvulcanized rubber cylinder 4 Short fiber 5 Unvulcanized rubber 6 Extruder 7 Die 8 Guide rod 9 Unvulcanized rubber tube 10 Unvulcanized rubber tape 11 Cutter 12 Molding drum

Claims (11)

A method for producing a rubber cylinder containing short fibers,
By extruding unvulcanized rubber containing short fibers, an unvulcanized rubber tube in which the short fibers are oriented in the tube central axis direction is formed, and the unvulcanized rubber tube is cut into a spiral shape. Forming an unvulcanized rubber tape containing short fibers, and molding the unvulcanized rubber tape by rotating the molding drum around the unvulcanized rubber tube while rotating around its central axis as a rotation axis. The short fiber is oriented in a direction along the plane including the central axis of the unvulcanized rubber cylinder and the surface of the unvulcanized rubber cylinder, while spirally wound around the drum and molding the unvulcanized rubber cylinder, A method for producing a rubber cylinder, wherein the unvulcanized rubber cylinder is vulcanized and molded.   While the unvulcanized rubber tube is extruded around the guide rod and in the central axis direction of the guide rod, a cutter that cuts the unvulcanized rubber tube is rotated around the guide rod, thereby A vulcanized rubber tube is cut into a spiral shape to form the unvulcanized rubber tape, and simultaneously with the formation of the unvulcanized rubber tape, the molding drum is rotated while being moved in the extrusion direction of the unvulcanized rubber tube. The method for producing a rubber cylinder according to claim 1, wherein the rubber cylinder is wound around the molding drum in a spiral shape by rotating at the same rotational speed as the cutter.   The rubber according to claim 2, wherein the width of the unvulcanized rubber tape is adjusted by adjusting at least one of an extrusion speed of the unvulcanized rubber tube and a rotational speed of the cutter. A method for manufacturing a tubular body.   While changing the tape width by adjusting at least one of the extrusion speed of the unvulcanized rubber tube, the rotational speed of the cutter, and the position of the cutter in the central axis direction of the guide rod, The method for producing a rubber cylinder according to claim 2 or 3, wherein the inner diameter of the vulcanized rubber cylinder is changed along the central axis direction.   The molding drum is cantilevered and a ratio (L / D) of a length (L) to an inner diameter (D) in the central axis direction of the unvulcanized rubber cylinder is set to 10 or less. Item 5. A method for producing a rubber cylinder according to any one of Items 1 to 4.   When unvulcanized rubber tape is wound helically around the molding drum, the thickness of the unvulcanized rubber cylinder to be molded is adjusted by overlapping the side edges of the unvulcanized rubber tape winding part on the previously wound part. The method for producing a rubber cylinder according to any one of claims 1 to 5, wherein:   A manufacturing method of an air spring, wherein a diaphragm as a rubber cylinder is manufactured by the method according to claim 1, and a fastening fitting is attached to at least one end of the diaphragm. An apparatus for molding an unvulcanized rubber cylinder before vulcanization molding into a rubber cylinder,
A die, a guide rod that penetrates the die hole from the inside of the die and protrudes in the extruding direction, and supplies the unvulcanized rubber to the die while pressurizing the guide rod from the periphery of the die hole and the gap between the guide rods. An extruder for extruding an unvulcanized rubber tube around the guide, a cutter that circulates around the guide rod and spirally cuts the unvulcanized rubber tube to form an unvulcanized rubber tape, and the unvulcanized A molding drum for spirally winding a vulcanized rubber tape into an unvulcanized rubber cylinder,
The molding drum moves in the extrusion direction, and rotates around the guide rod at the same rotational speed as the cutter while rotating around its central axis as a rotation axis, thereby spiraling the unvulcanized rubber tape around it. An unvulcanized rubber cylinder molding apparatus characterized by winding.   The apparatus for molding an unvulcanized rubber cylinder according to claim 8, wherein the cutter is adjustable in a position in a central axis direction of the guide rod.   The unvulcanized rubber cylinder molding apparatus according to claim 8 or 9, wherein the unvulcanized rubber cylinder is molded from an unvulcanized rubber containing short fibers.   A fastener is attached to at least one end of a cylindrical diaphragm made of rubber containing short fibers, and the short fibers are oriented in a direction along the plane including the central axis of the diaphragm and the surface of the diaphragm. Features an air spring.

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