JP4068754B2 - Rubber hose manufacturing apparatus and manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a manufacturing apparatus for manufacturing a rubber hose having a constant outer diameter by passing a mandrel through a crosshead extruder, and in particular, a manufacturing apparatus suitable for manufacturing a rubber hose having a tapered portion on the inner surface and a constant outer diameter. And a manufacturing method.
[0002]
[Prior art]
FIG. 9 shows a rubber hose manufacturing apparatus using a conventional crosshead extruder. When the mandrel 1 passes through the crosshead die 3 of the known crosshead extruder 2, the rubber compound 4 is extruded and coated on the peripheral surface of the mandrel 1, and the rubber hose X having a constant outer diameter is manufactured. The mandrel 1 is fed to the crosshead extruder 2 by a feed conveyor 5 in which a plurality of rollers are arranged, and the tip is placed on a bed 7 attached to the drive conveyor 6 so as to be movable in the axial direction. Then, thrust is generated by the fluid pressure of the extruded rubber, and the mandrel 1 is moved. Further, centering for holding the shaft core of the mandrel 1 at a fixed position is performed by the receiving roller 9 fixed in the vacuum boot 8. In the figure, reference numeral 10 denotes a speed sensor.
[0003]
When the straight mandrel 1 is used in the above manufacturing apparatus, the rubber hose X having a constant outer diameter and inner diameter can be manufactured. By the way, a tapered rubber hose X having excellent wear resistance is used as a pumping tube used in a squeeze pump that performs slurry pumping of earth and sand or ready-mixed concrete.
[0004]
As this tapered rubber hose X, there is one in which the outer surface and the inner surface shown in FIG. 10 are tapered as disclosed in Japanese Patent Application No. 9-232154. The rubber hose X is manufactured by inserting an unvulcanized rubber hose X having a constant outer diameter that has already been extruded into the tapered mandrel 1. Therefore, the small diameter portion is thick, the large diameter portion is thin, and the outer surface is tapered.
[0005]
However, the tapered rubber hose X cannot be manufactured using the crosshead extruder 2. Accordingly, as a rubber hose X manufactured using the rubber hose X, a rubber hose X having a taper portion Xa on the inner surface and having a constant outer diameter as shown in FIG. 11 is disclosed in Japanese Patent Laid-Open No. 10-16075. Is manufactured as follows. That is, the mandrel 1 including the tapered portion 1a, the small diameter portion 1b, and the large diameter portion 1c shown in FIG. 12 is passed through the crosshead die 3 of the crosshead extruder 2, and an unvulcanized rubber compound 4 is formed on the peripheral surface of the mandrel 1. A rubber layer having a constant outer diameter is formed by extrusion coating, and a rubber layer reinforced with fibers is formed on the peripheral surface, and then vulcanized.
[0006]
[Problems to be solved by the invention]
In general, in a manufacturing apparatus using a crosshead extruder, a mandrel is moved in the axial direction while being supported by a roller or the like. Since the straight mandrel can be supported by the receiving roller in the vicinity of the cross head die, the shaft core is held at a fixed position.
[0007]
However, since the outer diameter of the tapered mandrel changes as it moves, the receiving roller can support the large diameter portion, but cannot support the small diameter portion and the tapered portion, and must support both ends. I must. Therefore, in the case of a product having a long or large diameter or a product having a large inner taper angle, for example, if the diameter of the rubber hose exceeds 125A, the weight of the mandrel 1 exceeds 50 kg, and the mandrel becomes large and heavy. As a result, bending is likely to occur, and the shaft core is displaced from the center axis of the crosshead extruder at the central portion in the axial direction, resulting in thickness fluctuation in the vertical direction and uneven thickness. In addition, since the mandrel deflection changes with fluctuations in the extrusion pressure, the wall thickness accuracy in the axial direction varies. Therefore, the dimensional accuracy of the product cannot be ensured, the quality is deteriorated, and the characteristics of the tapered rubber hose cannot be utilized. In this way, a product with a small diameter of 100 A or less and a length of about 3 m can be manufactured with a conventional method, but can be manufactured by a conventional method. Will have an impact.
[0008]
Therefore, in view of the above, an object of the present invention is to provide a manufacturing apparatus that can perform centering by holding the shaft core at a fixed position and manufacture a rubber hose X having no wall thickness variation.
[0009]
[Means for Solving the Problems]
In the present invention, in order to prevent the shaft core from deviating from the central axis of the crosshead extruder due to the bending of the mandrel, it is only necessary to support the mandrel that moves in the vicinity of the crosshead die. In addition, a rotating body that supports the mandrel is provided on the upstream side of the moving direction, the rotating body can be moved, and the position of the rotating body is adjusted according to the movement of the mandrel, whereby the mandrel is centered. By the way, in order to increase the accuracy of centering, it is desirable to arrange the rotating body as close to the crosshead die as possible. Alternatively, a rotating body may be provided at a plurality of locations in the axial direction to support the mandrel, and the cantilever can be prevented without being cantilevered.
[0010]
Therefore, if the mandrel has a tapered portion, the shaft core is always held at a fixed position by changing the position of the rotating body so as to approach or separate from the shaft core according to the change in the outer diameter. it can. As a result, accurate centering is performed when the mandrel is passed through the crosshead die of the crosshead extruder, and the rubber compound can be extruded and coated around the mandrel without variation in wall thickness. A rubber hose having a high dimensional accuracy with a constant outer diameter can be manufactured. Similarly, for straight mandrels, high-quality centering with high accuracy and constant outer diameter without fluctuations can be achieved by finely adjusting the position of the rotating body in response to small changes in outer diameter. The rubber hose can be manufactured. In addition, as a rubber compound, various rubber | gum and thermoplastic elastomer are included.
[0011]
Here, the rotating body is a plurality of supporting rollers arranged around the mandrel on the upstream side in the moving direction from the crosshead extruder, and the supporting rollers are movable in the radial direction with respect to the axis of the mandrel. The Or it is set as the guide roller which is arrange | positioned in the vicinity of a crosshead die and supports the lower part of a mandrel, and a guide roller is supported by a roller stand so that rolling is possible. If a detection means for detecting the position of the mandrel is provided, it is possible to quickly cope with a change in the outer diameter of the mandrel, and high-precision centering is possible.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
The rubber hose X manufacturing apparatus of the present embodiment passes a mandrel 1 having a taper portion 1a through a crosshead die 3 of a crosshead extruder 2 and moves the mandrel 1 in the axial direction while placing a rubber compound 4 around it. By forming the rubber layer by extrusion coating, a rubber hose X having a tapered portion Xa on the inner surface and a constant outer diameter as shown in FIG. 11 is manufactured. As a centering mechanism for holding the mandrel 1 in a fixed position, as shown in FIG. 1, a rotating body that supports the mandrel 1 on the upstream side of the crosshead die 3 in the moving direction, and a mandrel 1 shaft On the other hand, a moving means for moving the rotating body close to and away from the rotating body is provided, and a control device is provided for performing movement control of the rotating body according to the movement of the mandrel 1 in order to hold the axis of the mandrel 1 at a fixed position. Note that the basic configuration and manufacturing method of the manufacturing apparatus are the same as those in the past. In FIG. 1, 11 is a seal, 12 is a spindle, and 13 is a bypass valve.
[0013]
The rotating body is a circular guide roller 20 that supports the lower portion of the mandrel 1, and is disposed in the vicinity of the crosshead die 3 in the boot 8. A cradle 21 is provided below the guide roller 20, and the upper surface of the cradle 21 is formed as a flat surface inclined downward from the downstream side in the moving direction of the mandrel 1, so that the guide roller 20 can roll freely. To support. A hydraulic or pneumatic cylinder 22 is rotatably mounted around the support shaft 23 in the boot 8, and a guide roller 20 is rotatably mounted on the tip of the rod 24. The cylinder 22 is operated by the control valve 25, and the guide roller 20 rolls in the axial direction along the upper surface of the receiving base 21 by the expansion and contraction of the rod 24. Therefore, the guide roller 20 approaches and separates from the axial center of the mandrel 1. Thus, the cylinder 22 and the cradle 21 constitute moving means.
[0014]
As another form of the rotating body, as shown in FIG. 2, as the upper guide roller 20 a that contacts the mandrel 1 and the lower guide roller 20 b that contacts the cradle 21, the guide rollers 20 a and 20 b are attached to the support shaft 26. It is attached to the tip of an arm 27 that is rotatably supported. Then, as the moving means, the cradle 21 is movable in the axial direction, and is moved by a cylinder, a motor, etc., so that the lower guide roller 20b rolls along the upper surface of the cradle 21 and the upper guide roller 20a The mandrel 1 is moved close to and away from the axis of the mandrel 1. As described above, when a plurality of guide rollers 20a and 20b are provided, the resistance applied to each of the guide rollers 20a and 20b is reduced, and the movement becomes smooth.
[0015]
Further, on the outside upstream of the crosshead extruder 2, there are provided a vertical control roller 30 and a horizontal control roller 31 that support the mandrel 1 from four directions and perform positioning in the vertical direction and the horizontal direction, respectively. Each of the control rollers 30 and 31 is a pair of drum-shaped rollers arranged vertically or horizontally opposite to each other with the mandrel 1 interposed therebetween. The control rollers 30 and 31 are arranged on a frame (not shown) so as to be movable vertically or horizontally. It is supported. The control rollers 30 and 31 are moved so as to be close to and away from the axis of the mandrel 1 by moving means such as a cylinder or a motor. Therefore, even if the mandrel 1 having a different diameter is supported by the guide roller 20 and the vertical control roller 30, two points can be supported, and bending can be reduced.
[0016]
Here, during extrusion by the crosshead extruder 2, the mandrel 1 moves in the axial direction, and the thrust is obtained by the flow pressure of the extruded rubber compound 4. Therefore, the flow pressure changes depending on the outer diameter of the mandrel 1, and the extrusion speed (mandrel moving speed) changes. FIG. 3 shows changes in the moving speed when the screw rotation speed of the crosshead extruder 2 is kept constant. That is, when the outer diameter of the mandrel 1 is constant, the moving speed is constant, but the moving speed varies depending on the outer diameter, and when the small diameter portion 1b passes, the thickness of the rubber layer is large and the cross-sectional area is large. When the large-diameter portion 1c passes, the moving speed increases because the wall thickness is small and the cross-sectional area is small. In the taper portion 1a, the cross-sectional area gradually decreases as the outer diameter gradually increases, so that the moving speed increases in a quadratic function according to the moving distance.
[0017]
Therefore, in order to center the mandrel 1, the positions of the guide roller 20 and the control rollers 30, 31 must be controlled in accordance with the outer diameter of the mandrel 1. Therefore, a position sensor is provided as a detection means for detecting the position of the mandrel 1, and a control device for controlling the operation of the moving means based on the detection result of the position sensor is provided. As the position sensor, the detection roller 32 is brought into contact with the mandrel 1 and the moving distance of the mandrel 1 is detected from the number of rotations of the detection roller 32 rotating as the mandrel 1 moves. It is arranged near the side. The detection roller 32 is supported by a spring or the like and is movable in the radial direction following the change in the outer diameter of the mandrel 1. Instead of this, a speed sensor that detects the moving speed of the mandrel 1 may be used.
[0018]
Here, the detection means may be any means that can recognize the shape of the mandrel 1 in order to control the position of the guide roller 20 or the like. Therefore, in addition to the position sensor, a change in the outer diameter of the mandrel 1 is detected by a distance sensor using ultrasonic waves and light, and the shape of the mandrel 1 is detected from image information using a CCD camera. When using these, it is necessary to arrange them close to the guide roller 20 or the like.
[0019]
And since this position sensor is arrange | positioned in the upstream from the guide roller 20, the control apparatus estimates the outer diameter of the mandrel 1 in the position of the guide roller 20 based on the positional information from a position sensor. The operation of the cylinder of the moving means is controlled so that the shaft core is always at a fixed position. That is, if the current movement distance of the mandrel 1 is detected by the position sensor, the position of the mandrel 1 at the position of the guide roller 20 that is located at a substantially constant distance from the position sensor is known, and the mandrel 1 corresponding to the position is detected. Can be estimated. Similarly, a position sensor may be provided close to the control rollers 30 and 31 on the upstream side, and the movement of the control rollers 30 and 31 may be immediately controlled based on the detection result.
[0020]
Therefore, when the small-diameter portion 1b or the large-diameter portion 1c having a constant outer diameter passes through the guide roller 20, the guide roller 20 is moved to a position corresponding to the outer diameter and held at that position. Next, when the taper portion 1a passes, the time required for the taper portion 1a to pass is determined from the length and moving speed of the taper portion 1a, and the cylinder 22 may be operated only for that time. Since the moving speed is slow when the starting end passes through the crosshead die 3, the rod 24 of the cylinder 22 is slowly shortened, and the moving speed becomes faster as the end of the taper portion 1a is approached, so the rod 24 is gradually shortened faster. . As a result, the mandrel 1 is centered.
[0021]
Therefore, when the crosshead extruder 2 has a constant rubber extrusion amount, the center axis of the crosshead extruder 2 and the axis of the mandrel 1 coincide with each other while the axis of the mandrel 1 is held at a fixed position. Since the rubber compound 4 can be extruded and coated on the outer periphery of the mandrel 1, the thickness accuracy of the rubber layer is stable and uneven thickness does not occur, and the inner surface has a tapered portion Xa and a constant outer diameter. A quality rubber hose X can be manufactured.
[0022]
(Second Embodiment)
In the present embodiment, a mandrel 1 having tapered portions 1a formed on both sides with a large-diameter portion 1c as shown in FIG. 4 is used, and the manufacturing apparatus has basically the same configuration as the conventional one. As shown in FIG. 5, a centering mechanism is disposed between the infeed conveyor 5 and the crosshead extruder 2.
[0023]
Similar to the first embodiment, this centering mechanism includes a rotating body and moving means, and is provided at two locations in the axial direction, and can be supported in a more stable state than supporting the mandrel 1 at one location. 6 and 7, a plurality of drum-shaped support rollers 40 are provided around the mandrel 1 as a rotating body. The support rollers 40 are arranged at three positions so as to surround the mandrel 1 at equal intervals, and are attached to a mounting plate 42 having a hole 41 slightly larger than the outer diameter of the large-diameter portion 1c of the mandrel 1 so as to be movable in the radial direction. Yes. The mounting plate 42 is fixed to a moving table 43 that moves in a direction orthogonal to the axial direction, and the moving table 43 is moved along the rail 44 by a cylinder or the like.
[0024]
The roller shaft of the support roller 40 is attached to a rack gear 45 that is slidably supported on the attachment plate 42, and a rotation shaft 47 having pinion gears 46 fixed to both ends is provided through the attachment plate 42. . One pinion gear 46 meshes with the rack gear 45, and the other pinion gear 46 meshes with a ring gear 48 that is rotatably supported by the moving table 43. A rod 50 of a cylinder 49 attached to the moving table 43 is rotatably attached to the ring gear 48. Therefore, a moving means is constituted by each of these gears and the cylinder 49. When the cylinder 49 is operated, the ring gear 48 is rotated, and the pinion gear 46 is further rotated to move the rack gear 45 in the radial direction. The support rollers 40 are closely spaced from the axis of the mandrel 1 in synchronism.
[0025]
Further, a position sensor for detecting the position of the mandrel 1 is provided, and a control device for controlling the operation of the cylinder 49 based on the detection result is also provided. These may be the same as those in the first embodiment. However, since the support rollers 40 are provided at two positions shifted in the axial direction, the cylinder 49 is operated with a time difference.
[0026]
Thus, when the mandrel 1 is fed into the crosshead extruder 2, the cylinder 49 is operated according to the outer diameter of the mandrel 1. For example, in the case of corresponding to the small-diameter portion 1 b of the mandrel 1, when the rod 50 of the cylinder 49 is extended, the ring gear 48 rotates clockwise in FIG. 6, and each rack gear 45 is directed toward the axis via the pinion gear 46. Therefore, each support roller 40 sandwiches the mandrel 1 evenly. Therefore, the axis of the mandrel 1 is aligned with the central axis of the crosshead extruder 2. And since the outer diameter will become large gradually when the taper part 1a of the mandrel 1 approaches, the rod 50 of the cylinder 49 is shortened according to this. Then, the ring gear 48 rotates counterclockwise, and each rack gear 45 moves by the same amount so as to move away from the shaft center via the pinion gear 46, so that each support roller 40 puts the shaft core of the mandrel 1 at a fixed position. It moves according to the change in outer diameter while holding.
[0027]
Instead of controlling the operation of the cylinder 49 based on the detection result of the position sensor, a constant fluid pressure is supplied to the cylinder 49 so that the cylinder 49 automatically follows the change in the outer diameter of the mandrel 1. It may be. That is, when the outer diameter gradually decreases, the support roller 40 naturally moves toward the axis due to the pressure of the cylinder 49, and when the outer diameter increases, the support roller 40 moves the mandrel 1. Therefore, the support roller 40 automatically moves according to the outer diameter in response to releasing the pressure from the cylinder 49 by a pressure relief valve or the like, and the axis of the mandrel 1 can be held at a fixed position. it can. Therefore, the position of the support roller 40 is self-adjusted according to the outer diameter of the mandrel 1 without providing the detection means, and control is unnecessary.
[0028]
Therefore, the mandrel 1 can be centered by the centering mechanism immediately before the mandrel 1 is fed into the crosshead extruder 2, and the center axis of the crosshead extruder 2 and the axis of the mandrel 1 coincide. Therefore, the rubber compound 4 can be uniformly extruded and coated on the outer periphery of the mandrel 1, and a high-quality rubber hose X having a tapered portion Xa on the inner surface and a constant outer diameter can be manufactured.
[0029]
In addition, this invention is not limited to the said embodiment, Of course, many corrections and changes can be added to the said embodiment within the scope of the present invention. In the first embodiment, the upper surface of the cradle 21 may be curved as shown in FIG. 8, and the mandrel can be centered by moving the rod of the cylinder at a constant speed according to the movement of the mandrel. Control becomes easy. Such a curved surface may be formed according to a quadratic curve of the moving speed of the mandrel.
[0030]
In the second embodiment, a guide roller may be provided in the crosshead extruder, and the mandrel can be centered with higher accuracy. Further, the support roller may be provided in the cross head extruder, and conversely, the guide roller may be provided outside the cross head extruder.
[0031]
Further, the guide roller and the support roller may be moved by a motor. Further, instead of supporting the guide roller by the cradle, the guide roller is directly held by a screw jack, and this jack is moved up and down to move the guide roller. Are moved close to and away from the axis.
[0032]
Moreover, although the manufacturing apparatus of each embodiment is directed to a mandrel having a tapered portion, it is needless to say that the manufacturing apparatus can also be applied to manufacturing a rubber hose using a straight mandrel.
[0033]
【The invention's effect】
As is apparent from the above description, according to the present invention, when a rubber hose having a constant outer diameter is manufactured by extruding and covering the outer periphery of the mandrel with a crosshead extruder, the mandrel is maintained even if the outer diameter of the mandrel changes. Since the supporting position of the mandrel can be changed in accordance with the change in the outer diameter, the mandrel shaft core can always be held at a fixed position. Therefore, the mandrel shaft center is accurately centered with respect to the center axis of the crosshead extruder, the thickness accuracy is greatly improved, and a high-quality rubber hose without uneven thickness can be manufactured.
[0034]
In particular, in mandrels with tapered portions and long mandrels, the effect of restricting the bending is enhanced, and the dimensional accuracy of the wall thickness is stably obtained, and a rubber hose having a tapered portion on the inner surface and a constant outer diameter is increased. Suitable for manufacturing with precision. In addition, since it is a simple configuration in which a roller or the like is simply attached to an existing apparatus, the cost is not increased, and it is possible to easily cope with mass production of a rubber hose having a tapered portion on the inner surface.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a main part of a rubber hose manufacturing apparatus according to a first embodiment of the present invention. FIG. 2 is a view showing a guide roller of another embodiment. FIG. 5 is a schematic view of a rubber hose manufacturing apparatus. FIG. 6 is a side view of the centering mechanism. FIG. 7 is a front view of the centering mechanism. FIG. 9 is a schematic configuration diagram of a conventional rubber hose manufacturing apparatus. FIG. 10 is a cross-sectional view of a tapered rubber hose. FIG. 11 is a cross-sectional view of a rubber hose having a tapered portion on the inner surface and a constant outer diameter. FIG. 12 is a diagram showing a mandrel having a tapered portion.
DESCRIPTION OF SYMBOLS 1 Mandrel 1a Tapered part 2 Crosshead extruder 3 Crosshead die 4 Rubber compound 20 Guide roller 21 Receptacle 22 Cylinder 32 Detection roller 40 Support roller X Rubber hose Xa Tapered part

Claims (5)

  A manufacturing apparatus for manufacturing a rubber hose having a constant outer diameter by passing a mandrel through a crosshead die of a crosshead extruder and extruding and coating a rubber compound around the mandrel while moving the mandrel in the axial direction. A rotating body that supports the mandrel upstream of the crosshead die in the moving direction, and a moving means that changes the position of the rotating body with respect to the axial center of the mandrel is provided, according to the movement of the mandrel. Then, the moving means is driven to hold the mandrel shaft core in a fixed position.   A mandrel having a tapered portion is passed through a crosshead die of a crosshead extruder, and the mandrel is moved in the axial direction while extruding and covering the rubber compound around the mandrel. A manufacturing apparatus for manufacturing a fixed rubber hose, a rotating body that supports the mandrel upstream of the crosshead die in a moving direction, and a moving unit that moves the rotating body close to and away from the axis of the mandrel. Is provided, and the rotating body is moved in accordance with the movement of the mandrel to hold the mandrel axis in a fixed position.   The rotating body is composed of a plurality of support rollers arranged around the mandrel on the upstream side in the movement direction from the crosshead extruder, and the support rollers are movable in the radial direction with respect to the axis of the mandrel. The rubber hose manufacturing apparatus according to claim 2.   The rotating body is a guide roller that is disposed in the vicinity of the crosshead die and supports the lower portion of the mandrel, and the guide roller is rotatably supported by a cradle whose upper surface is inclined to detect the position of the mandrel. The guide roller is moved close to and away from the axis of the mandrel by moving the guide roller along the upper surface of the cradle based on the detection result of the detection means. The rubber hose manufacturing apparatus according to 2 or 3. When a mandrel having a taper is passed through the crosshead die of the crosshead extruder while moving in the axial direction, the mandrel can be moved closer to and away from the axial center upstream of the crosshead die. The rotating body is moved according to the progress of the mandrel while being supported by the rotating body, and the mandrel shaft core is held at a fixed position, and a rubber compound is extruded and coated around the mandrel, A method of manufacturing a rubber hose, comprising: a rubber hose having a tapered portion on an inner surface and having a constant outer diameter.

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