JPH069815B2 - Twin screw different diameter kneading extruder - Google Patents

Description

TECHNICAL FIELD The present invention relates to a kneading extruder having a twin-screw different diameter, and in particular, it is possible to widely adjust the kneading degree (drawing degree) accompanying the movement of the cylinder. And a new improvement for facilitating the operation of the axial movement of the cylinder during continuous operation.

[Prior Art] This type of twin-screw different diameter kneading extruder that has been conventionally used is shown in FIG. 4, for example, in Japanese Patent Publication No. 47-42583 and Japanese Patent Publication No. 58-87013. The disclosed configurations may be mentioned.

That is, in the figure, what is denoted by reference numeral 1 is a cylinder provided so as to be movable in the axial direction by a hydraulic cylinder 3 provided in the main body 2, and in this cylinder 1, two large diameter shafts are provided. First shaft hole 1a and wall 1f consisting of holes
A pair of 2 consisting of two small-diameter shaft holes partitioned by
The shaft holes 1b and 1c are continuously formed.

A rear end 1d of the cylinder 1 is configured to be able to contact a stopper portion 2a formed on the main body 2.
The moving distance in the axial direction of is measured by a dial gauge 4 arranged in contact with the rear end 1d.

In each of the shaft holes 1a to 1c, a first outer diameter different from each other is provided.
A pair of a first screw shaft 7 and a second screw shaft 8 integrally having a screw portion 5 and a second screw portion 6 are rotatably arranged in a meshed state with each other, and each screw shaft 7
And 8 are connected to the reduction mechanism 9 via a connecting shaft 10, and are provided in a state of being fixed in the axial direction.

The first screw part 5 is composed of raw material supply parts 7a and 8a formed by flights with small leads and kneading parts 7b and 8b formed by flights with large leads, and the screw shafts 7 and Between the screw portions 5 and 6 in 8, there are formed taper portions 7c and 8c forming different diameter portions at positions where the outer diameter changes.

The inner wall taper portion 1 is provided at the inner wall positions of the shaft holes 1b and 1c corresponding to the taper portions 7c and 8c in the cylinder 1.
e is formed, and a gap t ₁ is formed between each of the tapered portions 7c and 8c and the inner wall tapered portion 1e.

Therefore, in the above-described configuration, the cylinder is variably moved in the axial direction during the continuous operation to change the gap t _1, thereby changing the filling rate in the kneading parts 7b and 8b of the screw parts 5 and 6, and The residence time was also changed to adjust the kneading degree of the raw materials.

[Problems to be Solved by the Invention] Since the conventional twin-screw different diameter kneading extruder is configured as described above, it has the following problems.

That is, the flow resistance (pressure loss) of the raw material (resin) is provided by adjusting only the above-mentioned gap t ₁ , but in this case, as shown in FIG. 5, the taper portion 7c flows. The pressure loss calculation formula for the raw material (resin) can be simplified as follows: However, ΔP = resistance value μ = resin viscosity Q = resin passing amount W = passing width L = passing length t ₁ = resin passing gap, which can be obtained from the above equation (1), but the gap t _{Since 1} changes with the third power, it is necessary to precisely and finely adjust the relational position between the cylinder 1 and the screw shafts 7 and 8, and the taper angle of the taper portions 7c and 8c should be reduced to make a large movement of the cylinder 1. Although the amount of change in the clearance t ₁ is minimized, the relationship between the clearance t ₁ and the angle θ of the tapered portions 7c and 8c is t ₁ = sin θ ×, as shown in FIG. Since χ (cylinder movement amount) is expressed by (2), the limit between the two axes is usually 15 ° or more in the limited distance between the two axes.

Therefore, as shown in FIG. 3, when viewed in a portion where the cylinder movement amount χ is small, the third power of the clearance t ₁ is effective, so that the relationship between the resistance value ΔP and the cylinder movement amount χ has a very remarkable change degree. However, for example, since it also changes due to a subtle influence such as a thermal expansion change of the cylinder 1 that occurs when the cylinder 1 is switched from heating to cooling, it is extremely difficult to appropriately adjust the movement of the cylinder 1, and The range was also limited.

Furthermore, when a high kneading degree is desired, the gap t _{1 is} as much as possible.
However, since the tapered portions 7c and 8c come into contact with the cylinder 1, it is necessary to provide a mechanical stopper for keeping the minimum clearance t ₁ .

Therefore, when high kneading is required, there is also a problem that the specially manufactured high kneading screw must be replaced.

The present invention has been made to solve the above problems, and in particular, enables wide and easy adjustment of the kneading degree (drawing degree) accompanying the movement of the cylinder, and continuous operation. It is an object of the present invention to provide a kneading extruder having different biaxial diameters, which facilitates the operation of axial movement of the cylinder inside.

[Means for Solving the Problem] A twin-screw different-diameter kneading extruder according to the present invention includes a pair of screw shafts rotatably provided in a cylinder movably provided in an axial direction, and the screw shafts. A first screw part and a second screw part which are formed via a tapered part and have different outer diameters from each other, and an inner wall tapered part formed on the inner wall of the cylinder corresponding to the tapered part,
This is a configuration including a columnar portion formed adjacent to the tapered portion and an inner wall tubular portion formed adjacent to the inner wall tapered portion.

[Operation] In the twin-screw different diameter kneading extruder according to the present invention, a columnar portion is provided adjacent to the taper portion of the screw shaft, and the raw material resistance (resin resistance) of the cylindrical portion is added to the raw material resistance (resin resistance) of the taper portion. By adding (resistance), a higher kneading effect and wider adjustment than before can be performed, and the relationship between the cylinder movement amount and the resistance value is configured to be less sensitive than before, and the kneading degree can be adjusted with relatively low accuracy. Can be easily adjusted.

That is, according to the above-mentioned formula (1), the clearance t ₁ is effective as a cube, but the length L flowing there is proportional to a cube, so that the cylindrical portion is changed by changing the relative position of the cylinder and the screw shaft. Since the effective length D at which the inner wall cylinder overlaps becomes the resistance value, which is a change of the first power, as shown in A and B shown in FIG. 3, the resistance value Δ with respect to the cylinder movement amount χ.
The change characteristic of P has a much gentler gradient than before.

Therefore, when the cylinder is moved to the right in the state shown in FIG. 1, the taper portion, that is, the clearance t ₁ decreases in resistance in the opening direction, and at the same time, the effective length D of the columnar portion decreases and the resistance also decreases. By continuously forming the columnar portion and the tapered portion adjacent to each other, the resistance value can be added, and the change curve of the resistance value ΔP with respect to the cylinder movement amount χ can be remarkably gentle. .

[Embodiment] A preferred embodiment of a kneading extruder having a different biaxial diameter according to the present invention will be described in detail below with reference to the drawings.

The same or equivalent parts as those of the conventional example will be described using the same reference numerals.

FIGS. 1 to 3 are for showing a kneading extruder having a twin-screw different diameter according to the present invention. FIG. 1 is a sectional view showing the entire structure, and FIG. 2 is a main part of FIG. 3 is an enlarged sectional view showing
The figure is a characteristic diagram of the resistance value.

In the figure, reference numeral 1 denotes a cylinder provided axially movable by a hydraulic cylinder 3 provided in a main body 2, and a large diameter cylinder formed of two axial holes is provided in the cylinder 1. A pair of second shaft holes 1b and 1c composed of two small-diameter shaft holes partitioned by the first shaft hole 1a and the wall 1f are continuously formed.

A rear end 1d of the cylinder 1 is configured to be able to contact a stopper portion 2a formed on the main body 2.
The moving distance in the axial direction of is measured by a dial gauge 4 arranged in contact with the rear end 1d.

Inside the shaft holes 1a to 1c, a pair of first screw shaft 7 and second screw shaft 8 integrally having a first screw part 5 and a second screw part 6 having different outer diameters rotate in a state of being meshed with each other. The screw shafts 7 and 8 are freely arranged, are connected to the reduction mechanism 9 via a connecting shaft 10, and are fixed in the axial direction.

Each of the first screw parts 5 is composed of raw material supply parts 7a and 8a formed by a flight with a small lead, and kneading parts 7b and 8b formed by a flight with a large lead. Between the screw portions 5 and 6 of the screw rods 8 and 8, tapered portions 7c and 8c and cylindrical portions 7e and 8e, which form different diameter portions at positions where the outer diameter changes, are formed adjacent to and continuous with each other. .

An inner wall taper portion 1e is formed at an inner wall position of each of the shaft holes 1a and 1c corresponding to the taper portions 7c and 8c of the cylinder 1, and between the respective taper portions 7c and 8c and the inner wall taper portion 1e. Has a gap t ₁ .

Further, inner wall cylinders 1ba and 1ca are formed on the inner walls of the shaft holes 1b and 1c corresponding to the cylinder parts 7e and 8e, respectively, and the cylinder parts 7e and 8e and the inner wall cylinders 1ba are formed. Between 1 and 1ca, a gap t ₂ is formed and, as shown in FIG. 2, an effective length D that overlaps each other is formed.

The twin-screw different-diameter kneading extruder according to the present invention is configured as described above, and its operation will be described below.

First, by driving the reduction mechanism 9, the screw shafts 7 and 8 are driven.
When the resin raw material is supplied to the raw material supply portions 7a and 8a in the cylinder 1 under the condition that they rotate with each other in a meshed state with each other, the kneading portions 7b and 8b.
Thus kneaded is extruded to the outside through the gap t ₁ and t ₂ booster 11 which is composed of the second screw part 6 and Kakujikuana 1b and 1c via (extrusion section).

In the above-mentioned state, when adjusting the degree of kneading of the resin raw material in the kneading parts 7b and 8b, the cylinder 1 is moved in the axial direction by the hydraulic cylinder 3, and the size of the gap t _{1 and} the cylindrical parts 7e and 8e and the inner wall cylinder are adjusted. This can be arbitrarily performed by changing the effective length D between the portions 1ba and 1ca.

That is, in the present invention, by adding the resin resistance of the cylindrical portions 7e and 8e to the resin resistance of the taper portions 7c and 8c, a higher kneading effect and a wider adjustment than before can be achieved, and the cylinder movement amount χ and the resistance can be increased. The relationship of the value ΔP is not as sensitive as the conventional one, and the kneading degree can be adjusted with relatively low accuracy.

That is, although the gap t ₁ is raised to the third power according to the equation (1),
Since the length L flowing there is proportional to the first power, by changing the relative positions of the cylinder 1 and the screw shafts 7 and 8, the cylindrical portions 7e and 8e and the inner wall tubular portions 1ba and 1c are changed.
Since the effective length D in which a overlaps with each other becomes the resistance value, and this is the change of the first power, the change characteristic of the resistance value ΔP with respect to the cylinder movement amount χ is conventionally as shown by the curves A and B shown in FIG. It is clear that the slope is much gentler than the characteristic.

Therefore, when the cylinder 1 is moved to the right in the state shown in FIG. 1, the taper portions 7c and 8c, that is, the gap t ₁ moves in the opening direction, so that the resistance is lowered, and at the same time, the inner wall tube portions 1ba and 1ca are removed. Since the effective length D of the cylindrical portions 7e and 8e is also reduced and the resistance is reduced, the resistance value is added by continuously forming the cylindrical portions 7e and 8e and the tapered portions 7c and 8c adjacent to each other. Therefore, the change curve of the resistance value ΔP with respect to the cylinder movement amount χ can be widened gently.

Therefore, the moving operation of the cylinder 1 does not require extremely tight precision as in the conventional case, and an arbitrary kneading degree can be easily obtained by moving the cylinder 1 by a rough mechanism.

Further, the gap t on the curves A and Aa shown in FIG.
₂ shows the case where it is set smaller than the gap t ₂ in the curves B and Ba.

In the above state, the cylinder 1 is moved to the right,
Although the state in which the clearance t ₁ is opened and the effective length D of the cylindrical portions 7e and 8e is reduced has been described, contrary to the above, by moving the cylinder 1 to the left, the clearance t ₁ is closed and The effective length D of the cylindrical portions 7e and 8e can be increased.

[Advantages of the Invention] Since the kneading extruder having different biaxial diameters according to the present invention is configured as described above, the following effects can be obtained.

That is, in addition to the conventional configuration of the gap using the taper portion, the cylindrical portion corresponding to the inner wall cylinder portion formed in the cylinder is continuously formed, so that the degree of change of the raw material resistance (resin resistance) with respect to the cylinder movement amount. It is possible to significantly loosen, and it is possible to obtain a high kneading control (squeezing effect) and a wide kneading range extremely easily.

In addition, since the degree of change in the material resistance (resin resistance) with respect to the cylinder movement amount is gentle, the accuracy of moving the cylinder can be improved by an extremely rough configuration and adjustment operation, and the kneading degree can be adjusted easily during continuous operation. Becomes

[Brief description of drawings]

FIGS. 1 to 3 are for showing a kneading extruder having a twin-screw different diameter according to the present invention. FIG. 1 is a sectional view showing the entire structure, and FIG. 2 is a main part of FIG. FIG. 3 is an enlarged sectional view, FIG. 3 is a characteristic diagram showing the degree of change in resistance value with respect to the cylinder movement amount in the conventional configuration and the configuration of the present invention, and FIGS. 4 to 6 show a conventional biaxial different diameter kneading extruder. FIG. 4 is a cross-sectional view showing the entire structure, and FIGS. 5 and 6 are operation explanatory views showing the operation principle of the main part in FIG. 1 is a cylinder, 1e is an inner wall taper portion, 1ba and 1ca are inner wall cylinder portions, 5 is a first screw portion, 6 is a second screw portion,
7 is a first screw shaft, 8 is a second screw shaft, 7c, 8c
Is a tapered portion, 7e, 8e columnar portions, t ₁ is a gap, and D is an effective length.

Claims (1)

[Claims] 1. A cylinder provided so as to be movable in the axial direction.
A pair of screw shafts (7,8) rotatably installed in (1)
A first screw portion (5) and a second screw portion (6) formed on the screw shafts (7, 8) via taper portions (7c, 8c) and having different outer diameters, and the taper portion ( 7c, 8c) corresponding to the inner wall of the cylinder (1) corresponding to the inner wall tapered portion (1e) formed on the inner wall of the twin-screw different diameter kneading extruder, the taper portion
(7c, 8c) cylindrical portion (7e, 8e) formed adjacent to, and the inner wall tapered portion (1e) formed adjacent to the inner wall tubular portion (1ba, 1
ca), and the gap (t ₁ ) between the tapered portions (7c, 8c) and the inner wall tapered portion (1e) along with the axial movement of the cylinder ( ₁ ).
And the cylindrical part (7e, 8e) and the inner wall cylinder part
A twin-screw different diameter kneading extruder, characterized in that the effective length (D) polymerized and formed by (1ba, 1ca) is variable.