JP2010137452A - Screw and method of manufacturing interior finishing member for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a screw for molding a foam resin molded article resistant to impact from the outside and bending stress by uniformly dispersing foaming gas in the resin to eliminate bursting of bubbles of the foaming gas and the formation of cavities (voids), and a method of manufacturing an interior finishing member for a vehicle. <P>SOLUTION: The screw 1 is housed in a cylinder barrel to constitute a part of a molding machine. A region (a metering part Mz) in which resin is in a molten state, is composed of at least one flight 7. A side face, heading in an advancing direction of the resin, of the flight 7 is a concave curved surface 9, and the flight 7 has a plurality of notches 31 penetrating in the advancing direction of the resin. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a screw used in an extrusion molding machine or an injection molding machine for producing a foamed resin molded article made of a thermoplastic resin and a foaming agent, and a method for producing a vehicle interior member.

  An injection molding machine melts and plasticizes a material such as a thermoplastic resin with a screw provided therein, and molds it as a molded product used in the field of automobiles, home appliances, and the like. Generally, the screw has a three-part configuration in the axial direction, and includes a supply unit Fz into which material is charged, a compression unit Cz into which material is melted, and a weighing unit Mz into which material is kneaded and measured. Furthermore, the screw used in the injection molding machine has a spirally wound flight over its entire length, and the spacing and depth of the axially aligned flights are adjusted so that the material can be easily kneaded. It has been done.

  That is, the thermoplastic resin supplied to the supply unit Fz is melted by heat energy from the heater and shear energy from rotation of the screw in the supply unit Fz, compression unit Cz, and metering unit Mz formed in the axial direction of the screw. And kneaded. And the thermoplastic resin which passed through the process is inject | poured in a metal mold | die, and is shape | molded as a thermoplastic resin molded object.

  By the way, the foamed resin molded product is a product in which a foaming agent is blended or mixed with a raw material resin and the resin is foamed in a mold, and injection molding is performed by blending a foaming agent using conventional techniques. However, the same screw as described above was used.

  For this reason, some problems may arise depending on the material and additive of the thermoplastic foam resin to be molded. That is, in general, the decomposition temperature of the foaming agent is lower than the melting point of the thermoplastic resin, and the foaming agent having a low decomposition temperature starts to decompose near the starting point of the screw (supply part Fz). Foaming gas is generated by this decomposition, but the foaming gas leaks to the outside through the hopper without being almost impregnated with the thermoplastic resin having a high unmelted ratio near the hopper provided in the supply unit Fz. In other words, the conventional screw cannot efficiently knead the thermoplastic resin and the foaming gas of the foaming agent, resulting in a problem that a poor foamed resin molded product having a low foaming ratio is molded.

Patent Document 1 discloses a screw that solves such a problem.
JP 2003-145597 A

In order to prevent the leakage of foaming gas, the injection molding screw described in Patent Document 1 has a groove depth on the resin supply side (supply portion Fz) and a groove in a completely melted region of the resin (generally, the measurement portion Mz). The depth ratio (compression ratio) is low (1.5 or less).
That is, Patent Document 1 intends to suppress the extrusion of gas to the front side (hopper side) by lowering the compression ratio.

  However, according to the invention of Patent Document 1, in the cylinder barrel, the kneadability is insufficient due to a decrease in the compression ratio, the foaming agent is not sufficiently dispersed in the thermoplastic resin, and bubbles of the foaming gas burst or are fine In some cases, a foam gas is connected to form a void. As a result, the foamed gas is not uniformly dispersed in the molten resin. Therefore, according to the measure described in Patent Document 1, there is a problem that the distribution and size of the bubbles of the foaming gas in the molded body are not uniform.

  In order to prevent such problems, there is a method to reduce the screw rotation speed. However, the time for the molten resin to stay in the cylinder barrel is extremely increased, and the burning of the resin and the foaming stop and the foaming gas is stopped. However, there was a concern that the original effect would not be exhibited. On the other hand, there is a method of expecting a high shearing force by increasing the number of rotations of the screw. However, in the conventional screw, there is a case where the kneadability of resin or the like is lowered. That is, as the number of rotations of the screw increases, resin or the like is sent forward in a short time, and as a result, the resin is injected without being sufficiently kneaded. Therefore, in the conventional screw, since the foaming gas is not uniformly dispersed in the resin, the molded foamed resin molded product has a low expansion ratio. As a result, the obtained foamed resin molded article has a problem that the strength is unstable and it is weak against external impact and bending stress.

  Therefore, in view of the above-mentioned drawbacks, the present invention uniformly foams the foaming gas in the resin, and eliminates the bursting of bubbles of the foaming gas and the generation of voids, thereby making the foam resistant to external impact and bending stress. It aims at providing the screw which can shape | mold a resin molded product. Furthermore, it aims at providing the manufacturing method of the vehicle interior member using the screw.

  The invention according to claim 1 for solving the above-mentioned problem is a screw that is housed in a cylinder barrel and constitutes a part of a molding machine, and a region in which the resin is in a molten state is composed of at least one or more flights. The flight in the region has a concave curved side surface in the traveling direction of the molten resin, and the flight has a plurality of notches penetrating in the traveling direction of the resin. It is a screw.

  In the screw according to the present invention, since the side surface of the flight arranged in the region where the resin is in a molten state is a concave curved surface in the traveling direction of the molten resin, rotating the screw pushes up the earth and sand with the blade portion of the bulldozer. The action works and the material such as resin is easily kneaded. Specifically, the molten resin is pushed out in the direction of the tip of the cylinder barrel by rotating the screw. However, since the flight is formed in a curved surface shape, the molten resin moves along the curved surface. In other words, since the molten resin once proceeds in the opposite direction to the direction of extrusion and then proceeds to the tip side, the residence time of the molten resin or the like is extended, and an environment is easily mixed. Further, since the flight having a curved surface has a notch penetrating in the traveling direction of the resin, the flow direction of the molten resin changes. Thereby, since the lump of the connected foaming gas covered with the molten resin can be finely dispersed, the fine foaming gas can be uniformly dispersed in the molten resin. Thereby, the obtained foamed resin molded product has a high expansion ratio, and can be a molded product resistant to external impact and bending stress.

  The invention according to claim 2 is the screw according to claim 1, wherein a side surface facing the curved surface is a flat surface.

  In the screw according to the present invention, the curved surface is provided on the side surface on the flight direction side of the molten resin of the flight, and the side surface of the flight opposite to the curved surface (the side opposite to the molten resin traveling direction) is flat. When a resin or the like is pushed forward by rotation and gets over, a large shearing force can be applied to the resin or the like. That is, the side of the flight that does not have a curved surface, for example, a side surface of a plane extending perpendicular to the axis, can be a great resistance when resin or the like is pushed out in the distal direction. Due to the resistance, a shearing force is generated in the resin or the like when the screw rotates. Thereby, the kneadability of the resin and the like is further increased, the foaming agent and the foaming gas are uniformly dispersed in the molten resin, and the foaming ratio of the resin can be further increased.

  The invention according to claim 3 is the screw according to claim 1 or 2, wherein the notches are not arranged at positions adjacent to each other in the axial direction.

  The screw according to the present invention does not significantly reduce the compressive force applied to the resin or the like because the notch is not disposed at a position adjacent in the axial direction. That is, sufficient kneading between the molten resin, the foaming agent, and the foaming gas can be maintained by not arranging another notch before and after the notch is disposed in the axial direction. Thereby, it becomes possible to disperse the foamed gas lumps connected in the molten resin more finely.

  The invention according to claim 4 is the screw according to any one of claims 1 to 3, wherein the curved surface is 1 to 3 times the curvature of the circumference of the outer diameter including the flight. .

  It is recommended that the screw in the present invention be 1 to 3 times the curvature of the outer diameter including the flight.

  The invention according to claim 5 is characterized in that an axial vertical length of the notch is 1/6 to 3/4 times an axial vertical length of the flight. It is a screw in any one.

  In the screw according to the present invention, the axial vertical length of the notch is recommended to be 1/6 to 3/4 times the axial vertical length of the flight.

  The invention according to claim 6 is the screw according to any one of claims 1 to 5, wherein the length of the notch in the spiral direction of the flight is 1 to 2 times the width of the flight. It is.

  In the screw according to the present invention, it is recommended that the spiral length of the flight of the notch is 1 to 2 times the width of the flight.

  A seventh aspect of the present invention is a method of manufacturing an interior member for a vehicle formed using the screw according to any one of the first to sixth aspects.

  It is recommended that the screw according to any one of claims 1 to 6 be used in the method for manufacturing a vehicle interior member in the present invention.

  The manufacturing method of the screw of the present invention and the vehicle interior member includes forming a concave curved surface in the traveling direction of the molten resin in the flight region in the region where the resin is in a molten state, so that the molten resin, the foaming agent, and foaming are formed. Gas is kneaded efficiently. Thereby, since a foaming agent and foaming gas are uniformly disperse | distributed in molten resin, foaming gas does not form a void. That is, since the obtained foamed resin molded article can have a high expansion ratio, it can be strong against external impact and bending stress.

  Next, the screw 1 which is an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic view showing an injection molding machine. FIG. 2 is a schematic side view of the screw according to the embodiment of the present invention. 3 is an AA schematic cross-sectional view of the metering portion of the screw shown in FIG. 4 is a schematic cross-sectional view taken along the line B-B of the measuring portion of the screw shown in FIG.

The injection molding machine 11 includes a screw 1, a cylinder barrel 2, a heater 3, a hopper 5, and an injection cylinder (not shown).
The injection molding machine 11 is one in which a raw material such as a resin or a foaming agent is charged from the hopper 5 and is extruded and molded to the front end side of the cylinder barrel 2 by rotating the screw 1 disposed in the cylinder barrel 2. Specifically, the screw 1 is rotated at a preset rotation number using a motor (not shown), and the molten resin or the like can be advanced in the distal direction. In the process, the charged resin, foaming agent, and the like are melted and kneaded. When the kneaded resin or the like is accumulated on the tip end side of the cylinder barrel 2, an operation of pushing out the screw 1 is executed, and the resin is injected into the mold 4 and molded into a foamed resin molded product.

First, the thermoplastic resin and foaming agent used as raw materials will be described.
The thermoplastic resin material applied for foam molding is a resin that can be injected with a general screw 1 such as injection molding, injection compression molding, injection foam molding, etc., but is not particularly limited, but is polypropylene, polyethylene, polystyrene, propylene / ethylene. Examples thereof include polyolefin resins such as copolymers.
The chemical foaming agent is not particularly limited, and examples thereof include azodicarbonamide (organic compound) and bicarbonates (inorganic compounds) such as sodium bicarbonate.
In addition to the chemical foaming agent, if necessary, the foamable molten resin may be a known foaming aid, foam nucleating agent, foam molding stabilizer, stabilizer, ultraviolet absorber, antioxidant, antistatic agent, Lubricants, colorants, flame retardants, crosslinking agents and / or fillers can be blended. Incidentally, as the foaming aid, for example, stearates such as sodium stearate, calcium stearate, magnesium stearate, potassium stearate, zinc stearate, montanic acid (which is octacosanoic acid) calcium, zinc montanate, etc. Higher fatty acid metal salts such as montanates, urea or urea compounds, paraffin, and other stearamides.
Examples of the foam nucleating agent include inorganic fillers such as talc, silica, calcium carbonate, and calcium silicate.

Next, each member in the injection molding machine 11 will be described with reference to the drawings.
As shown in FIG. 1, the cylinder barrel 2 accommodates a screw 1 which will be described later, and an injection hole 22 through which molten resin is injected on the front end side and a raw material such as resin is charged on the rear end side. A slot 23 is provided.
Further, a hopper 5 for supplying a material such as a resin or a foaming agent is provided at the inlet 23 of the cylinder barrel 2.

The heater 3 is provided so as to cover the periphery of the cylinder barrel 2 described above. This heater 3 promotes the melting of the resin or the like.
The mold 4 has various shapes depending on the type of molding. A concave receiving port 25 provided with a filling flow path 24 is formed at a position where the molten resin is filled from the tip of the cylinder barrel 2. Yes. Note that the receiving port 25 has a shape into which the tip of the cylinder barrel 2 is fitted.

  The screw 1 includes a main body portion 12 and a check ring 13. Inside the main body 12, a substantially cylindrical shape having a spline shaft (not shown) at the substantially center, and a male screw (not shown) is formed at the tip of the main body 12. A check ring 13 formed in a substantially conical shape is screwed onto the male screw at the one end.

On the other hand, the rear end side of the screw 1 which is the other end is connected to the injection cylinder, and the screw 1 can be moved back and forth in the axial direction of the spline shaft. The injection cylinder is operated by driving a motor (not shown).
The spline shaft (not shown) restricts the rotation of the screw 1 but allows the screw 1 to move in the axial direction.

  Moreover, as shown in FIG. 1, the flight 21 is provided in the main-body part 12 of the screw 1 helically. Resin or the like passes through the groove 16 sandwiched between the flights 21. This flight 21 is formed by cutting.

  As shown in FIG. 1, the screw 1 of the present embodiment includes a supply unit Fz, a compression unit Cz, and a measuring unit Mz formed in the axial direction, and is continuously connected. In addition, the area | region where resin is a complete molten state is mainly used as the measurement part Mz.

  Since the compression part Cz in the main body part 12 has a conical shape without a top part and has a shape whose diameter increases toward the measuring part Mz, the diameter of the supply part Fz is smaller than the diameter of the measuring part Mz. In addition, since the combined diameter of the main body 12 and the flight 21 is constant for the entire screw 1, the position of the flight 21 is smaller at a position where the outer diameter of the main body 12 is smaller than at a position where the outer diameter of the main body 12 is large. The height (axial vertical length) is large. That is, the height of the flight 21 of the supply unit Fz is larger than the height of the flight 21 of the measuring unit Mz. In the compression part Cz, the height of the flight 21 decreases as the outer diameter of the main body part 12 increases.

  Further, the screw 1 of the present embodiment has a configuration in which the decomposed foam gas hardly leaks in the supply unit Fz and the compression unit Cz. Specifically, a gas leak prevention unit (not shown) having a certain length is provided at an arbitrary location at a position where the resin starts to melt in the supply unit Fz. The gas leak prevention unit is defined such that the combined diameter of the main body 12 and the flight 21 is D, and the length of the spiral flight 21 when the spiral flight 21 is rotated is a lead ΔL, and the flight 21 is expressed as ΔL / D <1. It is a site provided. It should be noted that ΔL / D = 1 is set for other portions in the supply unit Fz.

  That is, with such a configuration, the filling rate of the foaming gas is increased between the screw 1 and the cylinder barrel 2, and the gas is impregnated and sealed with the semi-molten resin, thereby preventing the foaming gas from leaking. The action is strengthened. When the resin is further kneaded and completely melted and sent to the measuring unit Mz, the foaming agent and the foaming gas are further dispersed in the resin in the measuring unit Mz.

  The screw 1 of the present embodiment has a feature in the configuration of the screw 1 in the region where the resin is completely melted, that is, the measuring portion Mz, and will be described in detail. In addition, since the flight 7 and the groove | channel 8 in the measurement part Mz differ from the above-mentioned flight 21 and the groove | channel 16, the number is changed for convenience.

  As shown in FIG. 2, in the measuring portion Mz, one flight 7 is spirally arranged with the lead ΔL ′ having a smaller interval than the above-described lead ΔL, and a groove 8 is formed by the flights 7. Specifically, the lead ΔL ′ of the flight 7 is 1/30 to 1/3 times the lead ΔL, but preferably 1/20 to 1/5 times the lead ΔL. The spiral angle θ of the flight 7 (an angle counterclockwise from an angle perpendicular to the axis of the main body 12 of the screw 1) is 5 degrees to 30 degrees, and preferably 5 degrees to 15 degrees.

  The height of the flight 7 is 1/10 to 2/3 times the height of the flight 21 in the supply unit Fz, but preferably 1/5 to 1/3. The width t of the flight 7 is 1/5 to 5/6 times ΔL ′, but preferably 1/3 to 5/6 times. The width w of the groove 8 is 1/6 to 2/3 times the lead ΔL ′ of the flight 7, but preferably 1/4 to 1/2 times.

  That is, by making the lead ΔL ′ of the flight 7 smaller than the lead ΔL and making the spiral angle θ smaller than the supply unit Fz and the compression unit Cz, a large compressive force is exerted on the molten resin passing through the groove 8 in the measuring unit Mz. Can be given. That is, with this large compressive force, a high shearing force can be applied to the resin or the like when the screw 1 is rotated. Thereby, the void (cavity) formed by connecting the foaming gas can be made into a fine foaming gas.

  Furthermore, as shown in FIG. 3, the screw 1 according to the present embodiment has a curved surface 9 in which the shape of the flight 7 of the measuring portion Mz is concave in the traveling direction of the molten resin. Specifically, the flight 7 has a fin shape used for a fan, and the curvature of the curved surface 9 is 1 to 3 times the curvature of the outer diameter D obtained by combining the main body 12 and the flight 7. Further, the side surface on the supply portion Fz side of the flight 7 is a vertical wall (plane) 10 substantially perpendicular to the axis of the main body portion 12, and the other side surface facing the curved surface 9 is concave in the traveling direction of the molten resin. is there. That is, the flight 7 has both a curved surface and a flat surface.

  Generally, molten resin or the like is kneaded while being moved in the direction of the tip of the screw due to the rotation of the screw due to the spiral shape of the screw. Since the screw 1 of the present invention extrudes the molten resin by the curved surface 9, the resin or the like is extruded along the shape of the curved surface 9. In other words, the resin or the like advances after retreating toward the supply portion Fz so as to be scooped by the blade portion of the bulldozer. The molten resin or the like pushed forward is pushed toward the vertical wall 10 and gets over the vertical wall 10. That is, the screw 1 of the present invention has the curved surface 9 so that even when it is injected at the same rotational speed as the screw of the prior art, the resin or the like can be further kneaded. It is possible to give a high shearing force to

  Further, the flight 7 is provided with a notch 31 as shown in FIGS. The notch 31 penetrates the flight 7 in the thickness direction (resin traveling direction), and divides the flight 7 into three equal parts for each lead ΔL ′. In other words, the flight 7 of the measuring unit Mz has two notches 31 arranged at equal intervals for each lead ΔL ′. Specifically, the notch 31 has a height (vertical length in the axial direction) of 1/6 to 3/4 times the height of the flight 7, but preferably 1/4 to 2/3 times. . The length of the notch 31 in the spiral direction is ½ to 3 times the width t of the flight 7, but preferably is 1 to 2 times.

  That is, by providing the notches 31 at equal intervals in the spiral direction of the flight 7, a part of the resin or the like that has collided with the vertical wall 10 is changed in flow path and advances from the notches 31 toward the front end. For this reason, the resin or the like is more easily kneaded, and the foaming gas refined by the compression action is uniformly dispersed in the resin.

  Therefore, in the present embodiment, by configuring the screw 1 as described above, as shown in Table 1, even when the rotational speed of the screw 1 is increased, the bubble diameter of the foaming gas does not increase and a void is formed. There is nothing. Specifically, when the rotational speed of the screw is 75 to 90 rpm, the bubble diameter of the foaming gas is 105 to 108 (μm). That is, it cannot be a foamed resin molded product having a so-called void having a bubble diameter of the foaming gas of 120 (μm) or more.

That is, if the screw 1 of this embodiment is used, the resin can be sufficiently kneaded even if the rotational speed of the screw is increased to about 90 rpm. As a result, the molded foamed resin molded product has a high expansion ratio because the fine foamed gas formed by kneading is uniformly dispersed in the resin. That is, the obtained foamed resin molded product satisfies the predetermined standard values (bending strength = 50 N / cm, low-temperature impact strength = 32.5 kg-cm), and thus is a molded product resistant to external impact and bending stress. is there. Specifically, the molded product molded by the screw 1 of the present embodiment has a bending strength of 68 to 75 (N / cm) and a low temperature impact strength of 36.2 to 42.6 (kg-cm). .
In addition, the expansion ratio said here is (apparent volume of a molded article) / (raw material resin weight).

  On the other hand, as a comparative example, a screw having the same conditions as those in the example except for the measuring part Mz was used. Therefore, a screw having the following conditions, which is a conventional technique, was used as the screw. The comparative example is a general-purpose full-flight screw (comparative example) that is generally used.

  As shown in Table 1, in the comparative example, the bubble diameter of the foaming gas in the measuring portion Mz is 127 to 135 (μm). Specifically, as in the embodiment, when the screw rotation speed is increased to about 75 to 90 rpm, the bubble diameter of the foam gas gradually increases in proportion to the increase. That is, a foamed resin molded article having voids having a bubble diameter of 120 (μm) or more is obtained. Therefore, the obtained foamed resin molded product is a molded product that is low in external bending stress and impact because the foaming ratio is low and the bending strength and the low-temperature impact strength do not reach predetermined reference values. Specifically, the molded product formed by the screw of the comparative example has a bending strength of 45 to 49 (N / cm) and a low temperature impact strength of 28.2 to 31.3 (kg-cm).

  The conventional screw has a large groove width constituted by flights in the measuring portion Mz, and the ratio of the flight width to the groove width is often small. Therefore, it can be said that when the number of rotations is increased, the amount of resin extrusion per time is increased in proportion to the number of rotations. In short, with the conventional screw, even if the rotational speed is about 90 rpm, the residence time is too short in the measuring section Mz, so that the molten resin is not sufficiently kneaded. Therefore, the foaming gas is pushed forward of the screw without being uniformly dispersed in the resin. Therefore, the screw of the prior art gradually increases the bubble diameter of the foaming gas when the rotational speed is increased, thereby forming a void. Moreover, since resin etc. cannot fully be knead | mixed, foaming gas is not disperse | distributed uniformly in resin, and the expansion ratio of the foamed resin molded product obtained cannot be made high.

The molding machines, molds, and molding conditions used in the examples and comparative examples are as follows.
Used injection molding machine: EC-160 (manufactured by Toshiba Machine Co., Ltd.)
Screw diameter φ36 mm L / D = 22 (L is the effective length of screw)
Cylinder barrel set temperature
Supply unit Fz 180 ° C (180 degrees Celsius)
Compression section Cz 200 ° C (200 degrees Celsius)
Weighing section Mz 190 ° C (190 degrees Celsius)
Thermoplastic resin: Polypropylene J830HV (manufactured by Prime Polymer Co., Ltd.) 100 parts by weight Chemical foaming agent: Polyslen EE275F (manufactured by Eiwa Kasei Kogyo Co., Ltd.) 3 parts by weight Mold cavity capacity (dimensions): 1150 mm (width) x 750 mm (length) ) X 1.5mm (thickness)

It is the table | surface which showed the experimental result of the above-mentioned Example and comparative example.

  From the experimental results, with the conventional screw of the comparative example, even if the amount of the foaming agent is increased, it cannot be efficiently taken in and dispersed in the resin by the measuring unit Mz, and the increased amount of raw material is wasted. . However, according to the screw 1 of the present embodiment, it is possible to efficiently take in the foaming gas in the measuring portion Mz even if the same amount of foaming agent is used.

  That is, as described above, the flight 7 provided in the measuring portion Mz has both the curved surface 9 and the vertical wall 10, and is further formed at equal intervals so that the notch 31 penetrates in the thickness direction of the flight 7. ing. If the screw 1 having such a configuration is used, the resin and the foaming gas are pushed out in the distal direction by the curved surface 9, and at that time, the resin or the like temporarily moves back along the curved surface 9 in the axial direction. Even if the rotational speed is the same as that of the conventional screw, the residence time becomes longer, and the foaming gas is uniformly dispersed by further kneading. Further, since the side surface of the flight 7 facing the curved surface 9 is the vertical wall 10, the resin or the like is subjected to a high shearing force when extruded in the tip direction, the kneadability is increased, and the foaming gas becomes fine bubbles. Moreover, since a part of resin etc. can change a flow path by the notch 31, a fine foaming gas is disperse | distributed more uniformly.

  Therefore, with the screw 1 of the present embodiment, the foaming gas secured by the gas leak prevention unit can be efficiently taken into the resin in the metering unit Mz, the bubbles of the foaming gas are made fine, and voids are formed. It is possible to obtain a foamed resin molded article having a high expansion ratio that is uniformly distributed and that does not form.

  Although the screw 1 of the said embodiment showed the structure which the supply part Fz in the main-body part 12, the compression part Cz, and the measurement part Mz integrated, this invention is not necessarily limited to this. For example, the supply unit Fz, the compression unit Cz, and the weighing unit Mz are connected by a segment, or ΔL (the length that travels in the axial direction when the flight 7 or the flight 21 rotates once) / D (the main body unit 12 And the flight 7 or the diameter of the flight 21) may be connected in segments. Even in such a case, it is necessary to provide the gas leak prevention unit in the supply unit Fz and provide the above-described configuration in the measurement unit Mz as in the above embodiment.

  Although the screw 1 of the said embodiment showed the measurement part Mz comprised by the 1 flight 7, this invention is not necessarily limited to this, It is comprised by 2 or 3 flight 7 The weighing unit Mz may be used.

  The screw 1 of the above embodiment may be formed by forming a groove and a groove as shown in the above embodiment by cutting a cylindrical iron-based material or the like.

It is the schematic which shows an injection molding machine. It is a schematic side view of the screw which concerns on embodiment of this invention. It is an AA schematic sectional drawing of the measuring part of the screw shown in FIG. It is BB schematic sectional drawing of the measuring part of the screw shown in FIG.

Explanation of symbols

1 screw 2 cylinder barrel 7 flight 8 groove 9 curved surface 10 vertical wall (plane)
11 Injection Molding Machine 12 Main Body 31 Notch

Claims (7)

A screw that is housed in a cylinder barrel and constitutes a part of a molding machine, and a region in which the resin is in a molten state is composed of at least one or more flights,
The flight of the region is a curved surface having a concave side surface in the traveling direction of the molten resin,
The flight has a plurality of notches penetrating in a resin traveling direction.   The screw according to claim 1, wherein a side surface facing the curved surface is a flat surface.   The screw according to claim 1, wherein the notch is not disposed at a position adjacent in the axial direction.   The screw according to any one of claims 1 to 3, wherein a curvature of the curved surface is 1 to 3 times a curvature of an outer diameter including the flight.   The screw according to any one of claims 1 to 4, wherein an axial vertical length of the notch is 1/6 to 3/4 times an axial vertical length of the flight.   The screw according to any one of claims 1 to 5, wherein the length of the notch in the spiral direction of the flight is 1 to 2 times the width of the flight.   The manufacturing method of the vehicle interior member shape | molded using the screw in any one of Claims 1 thru | or 6.

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