JP2017205985A - Rubber extrusion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber extrusion device capable of suppressing deterioration of productivity while enhancing filling property of a rubber in a casing.SOLUTION: A rubber extrusion device 1 includes casing 2 and a screw axis 3 accommodated inside of the casing 2. The casing 2 includes an injection port 21 for injecting an unvulcanized rubber G inside of the casing 2, a discharge port 22 for discharging the unvulcanized rubber G and a degasification port 23 positioned between the injection port and the discharge port and connected to a vacuum device. The screw axis 3 has a spiral blade 32 extruding the vulcanized rubber G in casing 2 toward the discharge port 22 with mixing. The spiral blade 32 includes a first blade 41 in upstream side than the degasification port 23 and a second blade 42 in downstream side than the degasification port 23. In at least a preceding part of the degasification port 23, the first blade 41 includes a gradation region 41A with tapering reed angle α.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rubber extrusion device for extruding unvulcanized rubber.

  Conventionally, in a rubber extrusion device, a deaeration port for degassing an unvulcanized rubber is provided in a casing.

  For example, Patent Document 1 below discloses a rubber extrusion device in which the transfer speed after degassing is higher than the transfer speed before degassing. Further, in the rubber extrusion device, immediately before the deaeration port, by providing a connecting piece for connecting axially opposed screw blades and reducing the flow path of the unvulcanized rubber, the rubber filling property is improved, The rubber is prevented from being discharged from the deaeration port (see paragraphs “0014” and “0015” of the same document).

Japanese Patent No. 4863392

  However, in the rubber extrusion device shown in Patent Document 1, since the flow path is rapidly reduced in front of the connecting piece, the flow resistance of the unvulcanized rubber is increased, so that the amount of rubber discharged is reduced. And productivity deteriorates.

  The present invention has been devised in view of the above circumstances, and has as its main object to provide a rubber extrusion device capable of suppressing deterioration of productivity while improving the filling property of rubber in a casing.

  The present invention is a rubber extrusion device for extruding unvulcanized rubber, and includes a casing and a screw shaft accommodated in the casing, and the casing puts the unvulcanized rubber inside the casing. An injection port for charging, a discharge port for discharging the unvulcanized rubber, and a deaeration port located between them and connected to a vacuum device; A spiral blade that extrudes the unvulcanized rubber while kneading the unvulcanized rubber toward the discharge port, and the spiral blade is a first blade on the upstream side of the degassing port and a downstream side of the degassing port. The first wing includes a gradation region in which the lead angle gradually decreases at least immediately before the deaeration port.

  In the rubber extrusion device according to the present invention, it is preferable that the second blade has a lead angle larger than a maximum lead angle of the gradation region.

  In the rubber extrusion device according to the present invention, it is preferable that the second blade has a lead angle larger than a maximum lead angle of the first blade.

  In the rubber extrusion device according to the present invention, it is preferable that the gradation region forms the entire range of the first blade in the screw shaft direction.

  In the rubber extrusion device according to the present invention, it is preferable that the gradation angle continuously changes the lead angle.

  In the rubber extrusion device according to the present invention, it is desirable that the lead angle of the gradation region changes stepwise.

  In the rubber extrusion device according to the present invention, in the gradation region, at least one first groove penetrating the first blade in the axial direction of the screw is formed, and the first groove is a groove toward the inlet. It is desirable to include an extension with a gradually increasing cross section.

  In the rubber extrusion device according to the present invention, it is preferable that the extension portion is provided at an end portion of the first groove on the inlet side.

  The rubber extrusion device according to the present invention further includes at least one connecting piece for connecting between blade surfaces facing each other in the screw axis direction of the first blade in the gradation region, and the connecting piece includes the connecting piece. It is desirable that at least one second groove that penetrates through in a direction crossing the screw axis direction is formed.

  In the rubber extrusion device according to the present invention, it is preferable that the second groove is inclined at an angle substantially equal to the lead angle of the first blade.

  In the rubber extrusion device of the present invention, the first blade of the screw shaft on the upstream side of the deaeration port has a gradation region where the lead angle gradually decreases immediately before the deaeration port, so that the rubber discharge amount is maintained. However, the rubber filling property is gradually enhanced in the gradation region. This makes it possible to achieve both rubber filling properties and productivity in the casing.

It is sectional drawing which shows one Embodiment of the rubber extrusion apparatus of this invention. It is sectional drawing which expands and shows the gradation area | region of FIG. It is a perspective view which shows the screw shaft in the vicinity of the deaeration port of FIG. It is a side view of the screw shaft which expands and shows a part of 1st blade | wing of FIG. It is a side view of the screw shaft which shows the connection piece of FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view of a rubber extrusion device 1 according to this embodiment. As shown in FIG. 1, the rubber extrusion device 1 according to this embodiment includes a casing 2 and a screw shaft 3 accommodated in the casing 2. A gear pump 7 is provided on the downstream side of the casing 2.

  The casing 2 is located between the inlet 21 for feeding the unvulcanized rubber G into the casing 2, the outlet 22 for discharging the unvulcanized rubber G, and a vacuum device (not shown). And a deaeration port 23 connected to the other.

  The screw shaft 3 includes a shaft main body 31 and a spiral wing 32 protruding from the shaft main body 31 to the outside in the radial direction of the screw shaft 3. The spiral blade 32 is continuously formed in the circumferential direction while being displaced in the axial direction of the screw shaft 3. The spiral blade 32 pushes the unvulcanized rubber G in the casing 2 toward the discharge port 22 while kneading. Unvulcanized rubber G discharged from the discharge port 22 is supplied to the gear pump 7.

  The spiral blade 32 includes a first blade 41 on the upstream side of the deaeration port 23 and a second blade 42 on the downstream side of the deaeration port 23. The downstream end of the first blade 41 is formed continuously with the upstream end of the second blade 42. Thereby, the first blade 41 and the second blade 42 constitute one spiral blade 32 that is continuous in the axial direction of the screw shaft 3.

  The first blade 41 includes a gradation region 41A in which the lead angle θ1 changes at least at a portion 24 immediately before the deaeration port 23.

  FIG. 2 is a cross-sectional view of the rubber extrusion device 1 in the gradation region 41A. In the gradation area 41 </ b> A, the lead angle α of the first blade 41 gradually decreases from the inlet 21 toward the deaerator 23. When the lead angle α of the first blade 41 is gradually decreased, the pitch of the first blade 41 opposed in the axial direction of the screw shaft 3, that is, the flow path cross section of the unvulcanized rubber G is also gradually decreased. Accordingly, a rapid flow path reduction in the gradation area 41A is avoided, and the discharge amount of the unvulcanized rubber G from the discharge port 22 can be easily ensured. Further, as the flow path in the gradation area 41A is gradually reduced, the filling property of the unvulcanized rubber G passing through the gradation area 41A is gradually improved, and the unfilled portion 24 is not added in the portion 24 immediately before the deaeration port 23. The rubber rubber G is sufficiently filled. Thereby, it becomes possible to aim at coexistence with the filling property and productivity of the unvulcanized rubber G in the casing 2.

  In the present embodiment, as shown in FIG. 1, the lead angle β of the second blade 42 is constant. As shown in FIG. 2, the lead angle β of the second blade 42 is preferably larger than the maximum lead angle α1 of the first blade 41 in the gradation region 41A. Thereby, the extrusion speed of the unvulcanized rubber G from the discharge port 22 is increased, and a sufficient supply amount of the unvulcanized rubber G to the gear pump 7 is ensured. Moreover, the filling property of the unvulcanized rubber G in the portion 24 immediately before the deaeration port 23 is improved.

  Furthermore, the lead angle β of the second blade 42 is preferably larger than the maximum lead angle α2 of the first blade 41. Thereby, the extrusion speed of the unvulcanized rubber G from the discharge port 22 is further increased, and the supply amount of the unvulcanized rubber G to the gear pump 7 can be ensured sufficiently and easily. Moreover, the filling property of the unvulcanized rubber G in the portion 24 immediately before the deaeration port 23 is easily enhanced.

  The lead angle β of the second blade 42 may be configured to gradually increase from the deaeration port 23 toward the discharge port 22. Thereby, the extrusion speed of the unvulcanized rubber G from the discharge port 22 is further increased, and the supply amount of the unvulcanized rubber G to the gear pump 7 can be ensured sufficiently and easily.

  The gradation area 41 </ b> A desirably forms the entire range of the first blade 41 in the axial direction of the screw shaft 3, that is, the entire range upstream of the deaeration port 23. As a result, the lead angle α of the first blade 41 gradually decreases, the flow path in the gradation region 41A gradually decreases, and the discharge amount of the unvulcanized rubber G from the discharge port 22 can be easily ensured. .

  In the gradation area 41A, it is desirable that the lead angle α of the first blade 41 changes continuously. As a result, the lead angle α of the first blade 41 gradually decreases gradually, and the reduction of the flow path in the gradation region 41A becomes more gradual.

  In the gradation area 41A, the lead angle α of the first blade 41 may be changed in a stepwise manner. Such a screw shaft 3 is easy to design and manufacture, and the cost of the rubber extrusion device 1 can be easily reduced.

  FIG. 3 shows the screw shaft 3 in the vicinity of the deaeration port 23. It is desirable that at least one first groove 45 is formed in the first wing 41 of the gradation area 41A. The first groove 45 penetrates the first blade 41 in the axial direction of the screw shaft 3.

  Since the first groove 45 is formed in the first blade 41, a part of the unvulcanized rubber G passes through the first groove 45, and the flow resistance of the unvulcanized rubber G in the gradation region 41A is reduced. In addition, the discharge amount of the unvulcanized rubber G from the discharge port 22 can be more easily ensured. Further, the unvulcanized rubber G that passes through the flow path R surrounded by the shaft body 31, the first blade 41 that faces the axial direction of the screw shaft 3, and the inner wall of the casing 2 and the unvulcanized rubber that passes through the first groove 45. Good kneading is obtained by shear deformation generated between the rubber G and the rubber G. Furthermore, since the unvulcanized rubber G that has passed through the first groove 45 is kneaded with the unvulcanized rubber G on the downstream side, the kneading of the unvulcanized rubber G is further improved.

  Since the cross section of the first groove 45 is smaller than the cross section of the flow path R, the speed of the unvulcanized rubber G passing through the first groove 45 is higher than the speed of the unvulcanized rubber G passing through the flow path R. Also grows. Therefore, it is desirable that the extended portion 46 be formed in the first groove 45. The extended portion 46 is formed so that the groove cross section gradually increases toward the insertion port 21. By forming the extended portion 46 in the first groove 45, the flow resistance of the unvulcanized rubber G flowing into the first groove 45 is further reduced (that is, the pressure loss in the first groove 45 is reduced), and the discharge The discharge amount of the unvulcanized rubber G from the outlet 22 can be secured more easily.

  FIG. 4 shows the first groove 45 in an enlarged manner. The angle θ between the groove edges facing each other across the groove center line in the extended portion 46 is preferably 60 ° to 90 °. When the angle θ is less than 60 °, the high shear load region (region other than the expansion portion 46) occupying the first groove 45 is shortened, and the pressure loss can be reduced, but when passing through the first groove 45. There is a risk that the high shear deformation and high shear heat generation achieved cannot be obtained. On the other hand, when the angle θ exceeds 90 °, the effect of reducing the pressure loss by providing the extended portion 46 in the first groove 45 is limited.

  The extension 46 is preferably provided at the end of the first groove 45 on the inlet 21 side, that is, at the upstream side of the first groove 45. Such an extended portion 46 makes it easy for the unvulcanized rubber G to flow into the first groove 45 from the flow path R, and the discharge amount of the unvulcanized rubber G from the discharge port 22 can be more easily ensured.

  The corner of the intersection 46a between the extension 46 and the first groove 45 may be rounded. As a result, the unvulcanized rubber G easily flows from the extended portion 46 into the first groove 45, and the discharge amount of the unvulcanized rubber G from the discharge port 22 can be more easily ensured.

  As shown in FIG. 3, it is desirable that at least one connecting piece 47 is provided in the gradation area 41A. The connecting piece 47 connects the blade surfaces facing each other in the axial direction of the screw shaft 3 of the first blade 41. The connecting piece 47 is formed along the axial direction of the screw shaft 3. The connecting piece 47 is formed to protrude from the shaft body 31 to the flow path R. Accordingly, the unvulcanized rubber G flowing through the flow path R is blocked by the connecting piece 47, and the pressure of the unvulcanized rubber G on the upstream side of the flow path R is increased. As a result, the filling property of the unvulcanized rubber G in the portion 24 immediately before the deaeration port 23 is easily enhanced, and the unvulcanized rubber G easily flows into the first groove 45 from the flow path R. The kneading of the vulcanized rubber G is further improved.

  A plurality of connecting pieces 47 may be provided. In this case, it is desirable that the protruding height of each connecting piece 47 gradually increases toward the downstream side of the flow path R. Thereby, the filling property of the unvulcanized rubber G in the portion 24 immediately before the deaeration port 23 is easily enhanced.

  FIG. 5 shows the connecting piece 47. It is desirable that at least one second groove 48 be formed in the connecting piece 47. The second groove 48 penetrates the connecting piece 47 in a direction crossing the axial direction of the screw shaft 3 (that is, the thickness direction of the connecting piece 47).

  Since the second groove 48 is formed in the connecting piece 47, a part of the unvulcanized rubber G blocked by the connecting piece 47 passes through the second groove 48. Accordingly, the flow resistance of the unvulcanized rubber G is reduced while maintaining the filling property of the unvulcanized rubber G at the portion 24 immediately before the deaeration port 23, and the unvulcanized rubber G is discharged from the discharge port 22. The quantity can be easily secured.

  The second groove 48 is preferably inclined at an angle substantially equal to the lead angle α of the first blade 41 at both ends of the connecting piece 47. When the lead angles α of the first blades 41 at both ends of the connecting piece 47 are different, it is desirable to incline at the average angle. As a result, a part of the unvulcanized rubber G passing through the flow path R smoothly passes through the second groove 48, so that the flow resistance of the unvulcanized rubber G is reduced, and the unvulcanized from the discharge port 22 is reduced. The discharge amount of the rubber G can be easily secured.

  As mentioned above, although embodiment of this invention was described in detail, this invention is changed and implemented in various aspects, without being limited to said specific embodiment.

DESCRIPTION OF SYMBOLS 1 Rubber extrusion apparatus 2 Casing 3 Screw shaft 21 Input port 22 Discharge port 23 Deaeration port 32 Spiral blade 41 First blade 41A Gradation area 42 Second blade α Lead angle G Unvulcanized rubber

Claims (10)

A rubber extrusion device for extruding unvulcanized rubber,
A casing and a screw shaft housed in the casing;
The casing includes an inlet for introducing the unvulcanized rubber into the casing, an outlet for discharging the unvulcanized rubber, and a detachment unit positioned therebetween and connected to a vacuum device. Including mouthpieces,
The screw shaft includes a spiral blade that pushes out the unvulcanized rubber in the casing while kneading the unvulcanized rubber toward the discharge port,
The spiral wing includes a first wing upstream of the deaeration port and a second wing downstream of the deaeration port,
The rubber extruding apparatus according to claim 1, wherein the first blade includes a gradation region in which a lead angle gradually decreases at least immediately before the deaeration port.   The rubber extrusion device according to claim 1, wherein the second blade has a lead angle larger than a maximum lead angle of the gradation region.   The rubber extrusion device according to claim 1, wherein the second blade has a lead angle larger than a maximum lead angle of the first blade.   The rubber gradation device according to any one of claims 1 to 3, wherein the gradation region forms the entire range of the first blade in the screw axial direction.   The rubber extrusion device according to any one of claims 1 to 4, wherein the lead angle of the gradation region changes continuously.   The rubber extrusion device according to any one of claims 1 to 4, wherein the lead angle of the gradation region changes stepwise. In the gradation region, at least one first groove penetrating the first wing in the axial direction of the screw is formed,
The rubber extrusion device according to any one of claims 1 to 6, wherein the first groove includes an extension portion in which a groove section gradually increases toward the charging port.   The rubber extruding device according to claim 7, wherein the extension portion is provided at an end portion of the first groove on the inlet side. The gradation region further includes at least one connecting piece that connects between the blade surfaces facing each other in the screw axis direction of the first blade,
The rubber extruding device according to any one of claims 1 to 8, wherein the connecting piece is formed with at least one second groove penetrating the connecting piece in a direction crossing the screw axis direction.   The rubber extrusion device according to claim 9, wherein the second groove is inclined at an angle substantially equal to the lead angle of the first blade.

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