JPH0620587Y2 - Rotary screw for kneading - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention is used, for example, in an extruder for kneading and extruding a synthetic resin such as ABS resin and glass fiber or carbon fiber. The present invention relates to a kneading rotary screw, and more particularly, to a kneading rotary screw capable of obtaining a high quality raw material.

(B) Conventional Technique As the kneading rotary screw as described above, there is one disclosed in, for example, Japanese Patent Laid-Open No. 60-97805.

This screw has a first-stage kneading section and a second-stage kneading section on the same axis, and a kneading blade with a tip is provided in the first-stage kneading section to enable kneading action, In the kneading section,
An elliptical cavity that is long in the axial direction is provided so that a mixing action can be imparted.

Further, in this screw, the kneading blade with a tip of the first stage kneading section can obtain a kneading action, and the cavity of the second stage kneading section can obtain a mixing action.

(C) Problems to be Solved by the Invention However, in the screw of the above-described example, since the first-stage kneading section is formed by the kneading blades and the second-stage kneading section is formed by the oval cavity that is long in the axial direction, There are some difficulties.

Although the kneading blade has a strong shearing action, the unevenness of the unevenness makes it easier for the raw material flow to be constant.
A vigorous flow change such as pressure change and flow resistance change during kneading, and fine splitting and merging of raw materials does not occur, so that a positive stirring action cannot be obtained.

Further, in the second stage kneading section, the cavities are not formed in the spiral direction but along the axial direction, and since the cavities are not connected to each other, the raw material is considerably mixed in the second stage kneading section. It will be forcibly split and merged. As a result, twisting and pressure are applied to the raw materials due to the diverting and merging, and the residual stress is not sufficiently removed, or the various raw materials are extruded in a state where they are not uniformly blended. In this case, when the extruded raw material is cooled and solidified, deformation such as sink marks may occur in the kneading raw material due to residual stress during kneading.

Therefore, an object of the present invention is to provide a rotary screw for kneading, which has a better kneading action and can obtain a high quality raw material.

(D) Means for Solving the Problems This invention is directed to a first kneading section at the rear of the peripheral surface of the rotary screw in the transfer direction, and a second kneading section at the front of the transfer direction at a predetermined interval.
Each of the kneading parts is provided, and the first kneading part is provided with a wide kneading concave part deeper toward a central part, and narrow kneading concave parts formed in zigzag in a spiral direction on both sides centering on the wide kneading concave part,
The wide kneading concave portion and the narrow kneading concave portion are formed in the width direction of the spiral and are connected to each other by a raw material flow passage,
The kneading part is a kneading rotary screw composed of a large number of kneading recesses formed in a zigzag pattern along the spiral direction and deeper toward the center, and a raw material flow passage engraved adjacent to these kneading recesses. Characterize.

(E) Action In this invention, the raw material transferred by the rotating action of the rotary screw is first forcibly kneaded at a high pressure by the first kneading section arranged at the rear position in the transfer direction. The first kneading section has a wide kneading concave portion deeper toward the center, narrow kneading concave portions formed in zigzag along the spiral direction on both sides of the wide kneading concave portion, and the wide kneading concave portion. Since it is composed of a narrow-flow kneading concave portion and a raw material flow passage engraved in the width direction of the spiral and connecting the two, the raw material is a turbulent flow phenomenon due to a pressure change between each kneading concave portion and the non-kneading concave portion. , Turbulent pulsation phenomenon due to pulsation phenomenon due to change in flow resistance due to depth of each kneading recess. Furthermore, due to the arrangement of the kneading recesses and the raw material flow passage, the raw material undergoes a severe flow change in which the raw material is split and merged left and right with respect to the feeding direction.

The raw material kneaded in the first kneading section is transferred in the screw direction in the screw section in front of the first kneading section, the residual stress is removed and the material is made uniform, and further arranged in the front side in the transfer direction. The kneading is performed by the second kneading section. The second kneading section is composed of a large number of kneading recesses formed in a zigzag pattern along the spiral direction and deeper in the central portion, and a raw material flow passage engraved in the adjoining part of the kneading recesses. A part of the raw material sequentially flows from the kneading concave portion to the adjacent kneading concave portion through the raw material flow passage. That is, the raw materials are kneaded and extruded at a lower pressure than in the first kneading section.

(F) Effect of the device According to this device, the residual stress of the raw material added by the compulsory kneading in the first kneading part is applied to the screw part between the kneading parts arranged at two positions in the front and rear in the transfer direction. It can be sufficiently removed so that various raw materials can be adjusted to a homogeneous kneaded state.

Moreover, since the uniformly kneaded raw material kneaded in the first kneading section described above is further kneaded in the second kneading section at a low pressure, various raw materials can be kneaded more uniformly. In this kneading in the second kneading section, since the raw materials are sufficiently kneaded in the first kneading section, it is not necessary to forcibly knead at a high pressure, and it is possible to prevent the occurrence of residual stress. Therefore, high quality raw materials can be surely obtained.

In addition, the shape of the first kneading section allows a positive stirring action, and the second kneading section enables efficient kneading at a low pressure.

Moreover, since the depths of the respective kneading recesses are sequentially made different in the spiral direction, it is possible to prevent the raw material from being pressure-fed along the concave surface thereof and staying in the raw material. Therefore, a homogeneous raw material can be obtained.

(G) Embodiment An embodiment of the present invention will be described in detail below with reference to the drawings.

The drawing shows a kneading rotary screw used in an extruder. In FIG. 1, the kneading rotary screw 1 has a different axial peripheral surface of the rotary screw 2 in which a screw groove 2a having a spiral groove shape is engraved. The first kneading section 3 having a kneading groove shape is engraved at the rear side in the transfer direction and the second kneading section 4 is arranged at the front side in the transfer direction at predetermined intervals in the axial direction, and in front of the first kneading section 3. An adjusting ring 5 for adjusting the outflow amount of the raw material from the first kneading section 3 is arranged at the position.

As shown in FIG. 2, the above-described first kneading section 3 has a large number of wide kneading recesses 3a ... and each of the narrow kneading recesses 3b, 3c on the outer peripheral surface of the shaft formed to have the maximum outer diameter of the rotary screw 2. ... and are engraved along the spiral direction.

Each of the wide kneading concave portions 3a described above is formed such that the central portion in the spiral direction is deepest inscribed, while the central portion in the spiral direction is gradually inscribed shallowly in the front and rear portions along the spiral direction.

The narrow-width kneading recesses 3b, 3c, ... Each of the narrow-width kneading recesses 3b, 3c, ... Further, in the spiral width direction of the wide kneading concave portions 3a ... And the narrow width kneading concave portions 3b, 3c at both sides, adjacent side edges are used as raw material flow allowing portions in the spiral width direction. The respective raw material flow passages 3d ... Are formed and connected to each other by being polymerized with each other.

As shown in FIG. 3, the second kneading section 4 has a large number of kneading recesses 4a ... Staggered along the spiral direction on the outer peripheral surface of the shaft formed to have the maximum outer diameter of the rotary screw 2. Engraved,
Each of the kneading recesses 4a ... Is engraved deepest in the central part in the spiral direction, and on the other hand, is gradually engraved in the front and rear parts along the spiral direction with the central part as the central part.
In the spiral width direction of the raw material, the raw material flow passage 4 is provided adjacent to each kneading recess 4a as a raw material flow allowing portion in the spiral width direction.
b ... are respectively engraved and connected.

As shown in FIG. 4, the adjusting ring 5 is screwed to the connecting portion of the rotary screw 2 which is divided into two parts in front and rear of the first kneading section 3 in the transfer direction. After being screwed to the screw portion 2b screwed on the one end surface of the shaft, they are fixed in position by mutual tightening force by the fixing nut 6 screwed to the screw portion 2b in advance, and are rotated in a direction to loosen each other. The fixed position of the adjusting ring 5 can be finely adjusted in the axial direction by the dynamic operation.

In the adjusting ring 5 described above, the rising surface facing the first kneading section 3 is formed as a tapered surface 5a having a steep inclination angle, and the other surface is formed as a tapered surface 5b having a smooth inclination angle. The amount of outflow of the raw material from the first kneading section 3 is limited by finely adjusting the facing gap between the smooth tapered surface 5b of the above and the tapered stepped section 7a formed on the inner peripheral surface of the heating cylinder 7 described later. To do.

As shown in FIG. 5, an extruder 8 using the above-mentioned kneading rotary screw 1 has, as described above, inside a heating cylinder 7 having an input port 9 at one end and an extrusion port 10 at the other end. The configured kneading rotary screw 1 is inserted and the base end is connected to a drive mechanism (not shown) such as a drive motor.

In the heating cylinder 7, the first vent hole 11 is provided on the axial peripheral surface between the first kneading section 3 and the adjusting ring 5, and the second vent hole is provided in front of the second kneading section 4 in the transfer direction. ., 12, band heaters 13 ... Are mounted on the outer peripheral surface, and a hopper 14 for charging raw materials is continuously provided at the charging port 9.

The illustrated embodiment is configured as described above, and the operation will be described below.

As shown in FIG. 5, the kneading rotary screw 1 is rotated in the direction of the arrow so that the raw material in the hopper 14 is quantitatively supplied into the heating cylinder 7 and is transferred toward the extrusion port 10 during the transfer. While the raw material is heated and melted by the band heater 13, the raw material is forcibly kneaded at a high pressure when passing through the first kneading section 3.

In the first kneading section 3, the wide kneading concave section 3 is deeper toward the center.
a and a narrow kneading recess 3b formed in zigzag along the spiral direction at both sides centering on the wide kneading recess 3a.
, 3c, and the raw material flow passages 3d, which are formed in the spiral width direction of the wide kneading concave portions 3a and the narrow kneading concave portions 3b, 3c, and connect the two, the raw material is ,
Turbulence due to pressure change between the kneading recesses 3a ..., 3b ..., 3c.
A turbulent pulsation phenomenon is caused by the pulsation phenomenon due to the change of the flow resistance due to the depth of 3b. Furthermore, the arrangement of the kneading recesses 3a ..., 3b ..., 3c ... and the raw material flow passage 3
The raw material is split left and right with respect to the feeding direction because of d ...
The flow changes violently due to repeated merging.

After the kneading in the first kneading section 3, the amount of raw material outflow from the first kneading section 3 is adjusted by adjusting the adjustment ring 5 and the step 7a of the heating cylinder 7.
The air bubbles mixed in the raw material are squeezed out by restricting the gap between the raw materials and the high pressure to the raw material, and the bubbles are evacuated from the first vent hole 11. Then, while the raw material is being transferred in the spiral direction in the screw portion 2a after the first kneading portion 3, the pressure in the screw portion 2a is slightly lowered to remove the residual stress applied to the raw material in the first kneading portion 3. Remove.

Further, when passing through the second kneading section 4, the raw material is positively kneaded at a pressure lower than that of the first kneading section 3.

In the second kneading section 4, a large number of kneading recesses 4a formed in a zigzag pattern along the spiral direction are deeper in the central portion, and raw material flow passages 4b formed in the adjoining parts of the kneading recesses 4a. Therefore, a part of the raw material is mixed in the kneading recess 4a ...
Through the raw material flow passages 4b to the adjacent kneading recesses 4a. That is, the raw material is kneaded and extruded at a pressure lower than that in the first kneading section 3.

Then, after degassing in the second vent hole 12, the homogeneously kneaded raw material is extruded from the extrusion port 10.

In this way, the residual stress of the raw material added by the forced kneading in the first kneading section 3 is sufficiently removed at the screw portion between the kneading sections 3 and 4 arranged at two positions in the front and rear in the transfer direction. Thus, various raw materials can be adjusted to a homogeneous kneaded state.

Moreover, since the uniformly kneaded raw material kneaded in the above-mentioned first kneading section 3 is further kneaded in the second kneading section 4 at a low pressure, various raw materials can be kneaded more uniformly. The kneading in the second kneading section 4 is performed by the first kneading section 3
Since the raw materials have been sufficiently kneaded, it is not necessary to forcibly knead them at a high pressure, it is possible to prevent residual stress from occurring, and it is possible to reliably obtain high-quality raw materials.

Further, the shape of the first kneading section 3 allows a positive stirring action, and the second kneading section 4 enables efficient kneading at a low pressure.

Moreover, since the respective kneading concave portions 3a ..., 3b ..., 3c ..., 4a ... Have different depths sequentially in the spiral direction,
The raw material is pressure-fed along the concave surface, and it is possible to prevent the raw material from staying. Therefore, a homogeneous raw material can be obtained.

[Brief description of drawings]

The drawings show an embodiment of the present invention, FIG. 1 is a side view of a rotary screw for kneading, FIG. 2 is an enlarged side view showing a first kneading section, and FIG. 3 is an enlarged side view showing a second kneading section. FIG. 4 is an enlarged side view showing an adjusting ring, and FIG. 5 is a vertical side view of an extruder using a kneading rotary screw. DESCRIPTION OF SYMBOLS 1 ... Rotating screw for kneading 2 ... Rotating screw 2a ... Screw part 3 ... 1st kneading part 3a ... Wide kneading concave part 3b, 3c ... Narrow kneading concave part 3d ... Raw material flow passage 4 ... 2nd kneading part 4a ... Kneading Recess 4b ... Raw material flow passage

Claims (1)

[Scope of utility model registration request] 1. A first kneading section is provided at the rear of the peripheral surface of the rotary screw in the transfer direction, and a second kneading section is provided at the front of the peripheral surface of the rotary screw at a predetermined interval.
Each of the kneading parts is provided, and the first kneading part is provided with a wide kneading concave part deeper toward the central part, and a narrow kneading concave part formed in zigzag in a spiral direction on both sides of the wide kneading concave part, The wide kneading concave portion and the narrow kneading concave portion are formed in the width direction of the spiral and connected to each other by a raw material flow passage, and the second kneading portion is formed in a zigzag pattern along the spiral direction. A kneading rotary screw composed of a large number of kneading recesses deeper toward the center and a raw material flow passage engraved in the adjacency of these kneading recesses.