JP3537896B2 - Heating cylinder for pre-plastic injection molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic injection molding machine in which a resin material melted in a plasticizing section is accumulated and measured in an injection section and then injected. The present invention relates to an improvement in a heating cylinder-side first connection block formed in a V-shape by connecting a heating cylinder and an injection cylinder on an injection section side with a first connection block and a second connection block having communication paths.

[0002]

2. Description of the Related Art In general, a screw prepra type injection molding machine includes a plasticizing section having a screw and an injection section having an injection plunger, and a molten resin plasticized in the plasticizing section passes through a communication passage. The resin in the injection chamber is injected into the mold cavity through a nozzle by an injection plunger. Conventionally, a check ball valve is provided in the communication passage to prevent the resin in the injection chamber from flowing back to the plasticizing portion during injection by the injection plunger. The pre-plastic injection molding machine has a large plasticizing ability as compared with the in-line injection molding machine because it has an independent plasticizing section, and is particularly effective for high cycle molding. There is a possibility that a problem may occur with respect to a material in which the retention of the resin is likely to occur and thermal decomposition is likely to occur.

[0003] In order to solve the above problem, the present applicant has proposed as disclosed in Japanese Patent Publication No. 5-37810 (Fig. 6).
), The plasticizing part side 10 and the injection part side 20 are connected to the heating cylinder 11 and the injection cylinder 23 via the first connection block 5 and the second connection block 9, and the passage 9 g of the second connection block 9. And the passage 30 of the nozzle adapter 22 are communicated by the bush 21, and the screw 12 capable of rotating and moving forward and backward is inserted into the heating cylinder 11, and is retracted by the rotation of the screw 12 (two thin lines from the solid line position). The plasticizing chamber 14 is formed (to the dashed line position), and the molten resin flows from the opening (passage) 5a of the first connection block 5 to the opening 31 on the injection chamber 25 side through the passages 9g and 30 to form the plasticizing chamber 14. Plunger 2 inserted into injection cylinder 23
4 is retracted, and the resin accumulated in the injection chamber 25 is measured. Then, when the metering reaches a certain amount, the screw 12 is advanced while the rotation is stopped, pressed against the contact surface 5m (see FIG. 7) formed on the first connection block 5, stopped, and stopped. Is closed, and injection is possible without a check valve so that the resin in the injection chamber 25 does not flow backward through the passages 30 and 9 g from the opening 31 side due to the advance of the plunger 24. In FIG. 6, reference numeral 4 denotes a key for determining a positional relationship between the heating cylinder 11 and the first connection block 5 and the second connection block 9, reference numerals 6, 7, and 8 denote set bolts, reference numeral 13 denotes a heater, and reference numeral 26 denotes a nozzle adapter. 22
A nozzle hole 28 communicating with the nozzle attached to the connecting portion 27 is an injection sub-path located on the opposite side of the opening 31 which is likely to become a resin pool.

The second connecting block 9 includes a mounting plate 9b formed in an arc shape so as to conform to the outer shape of the injection cylinder 23 and the nozzle adapter 22 inside the mounting swash plate 9a, and the mounting swash plate 9a.
A support plate 9c is integrally formed at the center of the mounting plate 9b to form a substantially triangular shape in a side view. At the center of the mounting swash plate 9a, at right angles to the mounting swash plate 9a, and at the mounting plate 9b.
The passage 9g communicating with the inside of the support plate 9c is smoothly drilled with a constant diameter in a direction perpendicular to the mounting plate 9b from a predetermined position. Holes 9d (four places in this figure) for a heater and seats and holes 9e for a thermocouple are drilled in appropriate places of the support plate 9c, and a key groove to be described later is cut and set in the mounting swash plate 9a. Tap hole for Holt 7 and mounting plate 9b
Are provided with holes for set bolts 8 and holes 9f for fixing the bolts to the injection cylinder 23 side. A spigot 9h is provided around the passage 9g at the center of the mounting swash plate 9a so as to fit with the projection 5e (see FIGS. 7 and 8) of the first connection block 5. This second connecting block 9
In the same manner as in the heating cylinder 11, the injection cylinder 23, the nozzle adapter 22, and the like, corrosion and wear occur due to corrosive gas generated from resin. For example, alloy tool steel such as SKD material or structural alloy steel using,
Surface treatment such as quenching or nitriding is applied (Heisei 2
Published the third edition on November 5th, Sanko Publishing Co., Ltd., author:
Akihiro Hiroe, Atsushi Iida "Easy Injection Molding Machine"
From application to recent technology-see pages 26-30).

The first connecting block 5 is also manufactured using the above-described steel material, and has a cylindrical shape as shown in a sectional view of FIG. 7 and a plan view of FIG. The steel material is cut into a predetermined thickness, then cut and drilled, and is manufactured in a square shape in an outer shape. Each part has an opening (passage) 5a, the heating cylinder 11 and equal to the diameter _{D 1} pores 5b, the contact surface 5c of the distal end of the heating cylinder 11, spigot and the diameter _{D 2} fitted with an end surface 11a 5d Is a depth H ₁ ,
The protrusions 5e fitted with spigot 9h of the second connecting blocks the diameter d _1, the height is protruded H _2, on the central surface side (in Fig. 7 upper contact side of the screw 12), A contact surface 5m having the same angle as the tip angle S of the screw 12 is formed on the periphery of the opening 5a, and a play surface 5n is formed by the play angle R so as to avoid full contact with the screw 12. The contact surface 5m may be in full contact, but the resin pressure to be pushed back from the injection chamber 25 is proportional to the area of the passage 5a.
m. The heating cylinder 11 and the second connection block 9 are provided at the center of one side on the outer peripheral side of the first connection block 5.
A key groove 5k for alignment with the mounting swash plate 9a is formed, and as shown in FIG. 8, mounting bolt holes 5f for connection with the heating cylinder 11 and mounting bolts for connection with the mounting swash plate 9a. The holes 5g are formed so as to be out of positional relation with each other.

As described above, when closing the passage 5a, the rotation of the screw 12 is stopped and the screw 12 is moved forward. However, since the moving distance of the screw 12 is short, the screw 12 is not moved until it comes into contact with the contact surface 5m. The screw 12 is slightly rotated. Further, when the screw 12 is rotated to start melting the resin, the tip of the screw 12 starts to rotate from the state of contact with the contact surface 5m, and the screw 12 is retracted by the pressure at which the resin material is melted ( Screw 1
(The forward and backward movements of 2 are the same, about 1 mm). Therefore,
Since the contact surface 5m is rubbed by the tip of the screw 12, it must be replaced due to wear. In addition, since the alloy tool steel or the structural alloy steel is quenched or nitrided, it is heat-treated at a high temperature such as quenching, so that the first connection block 5 having many holes is quenched or distorted, There is a possibility that the first connecting block 5 may be broken from the time of starting use.

[0007]

Problems to be Solved by the Invention
In order to commercialize the pre-plastic injection molding machine disclosed in Japanese Patent Application Publication No. 5-37810, the first connecting block 5 attached like a lid on the tip side of the heating cylinder 11 includes:
It is desirable to replace it regularly or irregularly in consideration of wear. Since there are a large number of holes such as the mounting bolt holes 5f and 5g, it is easy to induce burning distortion and burning cracks. Since the outer shape is adjusted to the shape of the mounting swash plate 9a, it is cut from a round steel into a square shape, so that the processing time becomes longer and the cost increases. And so on.

That is, the screw 12 and the contact surface 5m are in contact with each other with a pressing force stronger than the resin pressure for pushing the screw 12 back to close the opening 5a.
In addition, the screw 12 is rubbed by the screw 12 at a moment from when the screw 12 advances to a complete stop and until the screw 12 starts rotating and the pressure of the molten resin increases, so that the screw 12 is easily worn. On the other hand, the first connecting block 5 includes a screw 12
The hardness of the contact surface 5m is the same as or slightly lower than the hardness of the contact surface 5a. Since there are a large number of mounting bolt holes 5f and 5g, quenching occurs during quenching or burning distortion occurs. For example, in the case of burning distortion, when the first connecting block 5 is attached to the heating cylinder 11, Alternatively, when the first connection block 5 is attached to the second connection block 9 thereafter, a crack may be formed in the first connection block 5 or a gap may be formed in the attached contact portion. If a gap is formed in the crack or the contact portion, the molten resin enters the gap due to the pressure of the resin, and may eventually break the first connection block 5, and the resin leaks out therefrom, When the resin enters, the mounting bolts 6,
There is a possibility that an accident such as breaking of 7 may occur.

The cracking caused by the replacement, quenching or nitriding of the first connection block 5 due to the partial wear as described above, and the processing time loss due to the external shape have a serious effect on cost. Become. The first connection block 5 is located on the distal end side of the heating cylinder 11 and is also one of important components indispensable for the heating cylinder 11 as a resin passage.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and will be described with reference to FIGS. 1 to 5.
Plasticizing section (10) for rotating and plasticizing the synthetic resin material
And an injection plunger (24) in an injection cylinder (23).
And an injection section (20) for injecting the plasticized material from a nozzle by moving back and forth. The heating cylinder (1) having a first connection block (3) on the plasticization section (10) side.
1) and an injection cylinder (23) having a second connection block (9) on the side of the injection section (20) by connecting the two connection blocks (3, 9) to each other to form a communication path (1a, 9g, 30), and at the same time, the molten material is circulated from the plasticizing section (10) to the injection section (20), and at the time of injection, the screw (12) is advanced to make the first connection block (3). ), The leading end of the screw (12) is brought into contact with the screw (12) to close the passage (1a), and the first connecting block (3) is connected to the connecting flange (2) by the screw touch. The connecting flange (2) is formed of a flat disk, and the center of the connecting flange (2) is larger than the inner diameter (D ₁ ) of the heating cylinder (11). The diameter (d ₂ ) The screw touch bush (1) having a contact surface (1m) with which a part of the tip of the screw (12) comes into contact is inserted into the upper spigot (2j), and the connection flange is formed. (2)
The upper peripheral edge (1q) is tightly contacted with and fixed to the end surface (11a) by abutting and fixing the end surface (11a) of the heating cylinder (11) and the upper peripheral edge (1q). A lower fitting portion (1h) of the touch bush (1) projects from a lower spigot (2h) of the connection flange (2) to enable connection with the second connection block (9).

The screw touch bush (1)
The center of the screw (12) penetrates the resin passage (1a) at the center, the contact surface (1m) where a part of the tip of the screw (12) is in contact with the hole of the passage (1a), and the tip of the screw (12) thereby forming a larger angle (R) and the play surface (1n), the plane inner diameter _{(D 1)} larger in diameter than the _{(d 2)} and the said upper rim (1q) of said heating cylinder (11) In addition, the lower fitting portion (1h) is formed, and is integrally formed in a substantially convex shape in a side view.

The disk-shaped connecting flange (2)
Is a spigot (2d) that penetrates the lower spigot (2h) at the center of the disk, and sequentially fits with the upper spigot (2j) and the end face (11a) of the heating cylinder (11).
Are formed in a stepped shape, and mounting bolt holes (2) for connection with the heating cylinder (11) and the second connection block (9) are formed.
f, 2g), and one keyway (2k) is formed on the outer periphery of the disc-shaped connecting flange (2).

Further, the screw touch bush (1) is made of alloy tool steel or structural alloy steel by quenching or nitriding to have the same hardness as the screw (12), and the connecting flange (2) is made of heat and heat resistant. It is characterized in that it is made of a special purpose alloy steel having a corrosive property.

[0014]

[Action] diameter of the coupling flange (2) and the upper spigot (2j) and the fitting upper part is a mating portion of the screw touch bush (1) (1j) _{(d 2)} is, JIS (Japanese Industrial Standards) B0401 Although the fitting is firmly performed by the "fitting fit" defined in the "dimensional tolerance and fitting", the upper fitting portion (1) is fitted into the upper spigot (2j).
j) together, the end surface (11) of the heating cylinder (11).
a) is brought into contact with the upper peripheral edge (1q), the set bolt (6) is inserted into the mounting bolt hole (2g) around the upper peripheral edge (1q), and tightened sequentially. 1j) is tightly fitted and assembled, the contact surfaces (1i, 2i) are brought into close contact with each other, and the end surface (11
a) and the upper peripheral edge (1q) are tightly integrated with each other, and the screw touch bush (1) is fixed by fixing the connecting flange (2). (2i), it is tightly fixed so as to be sandwiched between them, so that there is no danger of resin leaking from both joint surfaces, and the tightly fitted upper spigot (2
Since j) and the upper fitting portion (1j) are tightly fitted, it prevents the molten resin from flowing into this portion. Although the connecting flange (2) and the screw touch bush (1) are manually operated, by fixing the connecting flange (2) to the heating cylinder (11), the fitting is performed firmly, if not mechanically. I have. Screw (12)
Although the screw touch bush (1) does not use bolts or detents when the screw touch bush (1) is contacted or retracted momentarily at the time of forward or rotation start, the screw touch bush (1) There is no such thing as rotating.

Further, the screw touch bush (1) which comes into direct contact with the molten resin is a small screw touch bush (1) which is considered to be easily affected by gas generated when the resin melts. Contributes to improved compatibility.

Since the connecting flange (2), which does not come into direct contact with the molten resin, is cut and finished by cutting a cylindrical round steel, unlike the conventional example, the outer shape is not cut into a square shape. Is shortened, which greatly contributes to cost reduction.

Further, a screw touch bush (1)
Quenching or nitriding alloy tool steel or structural alloy steel that has heat resistance, wear resistance and corrosion resistance, and for the connecting flange (2), select special purpose alloy steel excellent in heat resistance and corrosion resistance. Since the performance as a part according to the purpose can be given, the maintenance of the machine such as maintenance and inspection and maintenance is improved.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a partially assembled view, FIG. 2 shows a first embodiment of a screw touch bush 1, FIG. 3 shows a second embodiment of the screw touch bush 1, and FIGS.
Will be described. Except for the screw touch bush 1 and the connecting flange 2 according to the present invention, and the first connecting block 3 in which both are combined, the same reference numerals used in FIG. 6 are assigned to the same parts, and FIGS. The description will be given with the supplementary codes (a, b, c...) Used in FIGS. Since the first connecting block 3 is based on the premise that the conventional second connecting block 9 and the heating cylinder 11 are used, the thickness T ₁ and the height T ₂ are fixed.

First, an embodiment of the screw touch bush 1 will be described with reference to FIGS. 2 and 3.
Slightly wider cut than slightly larger material round steel height T ₂ than the diameter d ₂ of the center to penetrate the passage 1a, the contact surface on one side which is from the upper peripheral edge 1q and the angle S around the passage 1a 1m and slightly larger than the diameter of the contact surface play surface 1n and the screw 12 which is an angle R from the predetermined position of 1m, the inner diameter D ₁ the same as the hole 1b of the heating cylinder 11 is formed, part inlaid top By forming 1j and the lower fitting portion 1h, the contact surface 1i and the convex portion 1e as a whole are finished in a convex shape in side view. Diameter d of upper fitting portion 1j
_2, interference fit with the upper spigot 2j of the connecting flange 2 to be described later, the diameter d ₁ of the lower fitting-in portion 1h, together with the clearance fit to the lower spigot 2h penetrating the connecting flange 2, abutting surface 1i Are fitted so as to be in close contact with the contact surface 2i.

The second embodiment shown in FIG. 3 is different from the first embodiment in that the play surface 1r is formed at an angle P smaller than the contact surface 1m.
This is provided near the passage 1a, and is effective for preventing a hole of the penetrating opening 1a from being blocked like a burr on the passage 1a side even if the contact surface 1m is set. The play surface 1r, the contact surface 1m, and the play surface 1n are divided into three angles P,
Although joined by S and R, similar results can be obtained by forming them by a series of circular arcs.

This screw touch bush 1 is generally made of alloy tool steel or structural alloy steel, and sometimes made of carbon steel.
Chromium, nickel-chromium, chromium-molybdenum, chromium-vanadium, silicon-manganese steel, etc., the amount of added elements is adjusted, the carbon amount is 0.2-0.5% of ordinary,
Heat treatment, abrasion resistance, and corrosion resistance are improved by performing carburization (cementation), surface hardening (case hardening), subzero treatment (subzero treatment), or surface nitriding.

Further, when the screw touch bush 1 is made of, for example, chromium-molybdenum steel and is subjected to chromium diffusion treatment instead of carburization diffusion treatment, the surface thereof becomes Fe--Cr.
A ferrite layer is formed, and Cr-C carbides are scattered in the layer, so that the surface has improved corrosion resistance and abrasion resistance.
At about 0 ° C., there is no layer change, and a surface layer having heat resistance can be formed. Accordingly, by making the portion that comes into contact with the screw 12 a separate screw touch bush 1, the furnace for heat-treating the screw touch bush 1, which has been reduced in size like an insert piece, can be made small. It is possible to greatly expand the range of treatments suitable for improving the wear resistance and the wear resistance and the corrosion resistance and the selection of the steel material.

Next, the connecting flange 2 is formed by cutting a round steel material having a columnar outer diameter (outer shape) to a thickness T ₁ + depth H ₁ thicker than the thickness, including a cutting allowance, and cutting the same at the center thereof. Convex part 1e
(Axis) and the relationship between the diameter d ₁ of the lower spigot 2h (hole) through the lower portion spigot 2h which was loose fit, also,
Upper spigot 2j fitted with upper fitting 1j (shaft)
The spigot 2j to interference fit the relationship between the diameter _{d 2} of the (pores), the spigot 2d which mate with the end face 11a (the axis) of the heating cylinder 11 to the diameter _{D 2} (hole), the spigot 2d
Depth _{H 1} is slightly deeper than the height _{H 1} of the end face 11a (in this case, about 0.05~0.1mm deep) to a depth _{T 0} of the upper spigot 2j is fitted the upper portion of the screw touch bush 1 height _{T 0} the same depth of the write portion 1j (however, since here deeply about 0.05~0.1mm as described above, correspondingly shallower depth) is processed as. Furthermore, the contact surface 2c with the heating cylinder 11, the contact surface 2q with the end surface 11a, the contact surface 2i with the contact surface 1i of the screw touch bush 1, and the mounting swash plate 9a in the second connection block 9 By forming the contact surface 2p in a planar shape, the lower spigot 2
h, the upper spigot 2j and the spigot 2d are formed with contact surfaces 2i, 2q, and 2c in a stepwise manner. This spigot 2h,
2j and 2d and the mounting bolt hole 2
The connection flange 2 is completed by piercing or cutting f, 2g and the keyway 2k at predetermined positions.

The connecting flange 2 does not come into direct contact with the molten resin, but is attached to the heating cylinder 11 so as to cover the screw touch bush 1 with the screw touch bush 1 fitted in the upper spigot 2j. Since it is attached and connected to the second connection block 9 via the connection flange 2, steel having heat resistance and corrosion resistance in addition to general mechanical properties may be used. Therefore, for example, it is processed using a special purpose alloy steel such as stainless steel, and in some cases, it is quenched for the purpose of improving corrosion resistance, so that its durability can also be improved.

The screw touch bush 1 and the connecting flange 2 have been described above.

When the screw touch bush 1 is assembled to the connecting flange 2, it becomes the first connecting block 3 having the same function as the conventional first connecting block 5, but this assembly is integrated by press fitting. It is also possible to assemble. However, in the present invention, since the screw touch bush 1 of the first connection block 3 needs to be replaced due to wear, the assembling work is performed at the site where the injection molding machine is placed. State.

That is, the upper fitting portion 1j of the screw touch bush 1 is connected to the upper spigot 2j of the first connecting flange 2.
Insert the heating cylinder 11
The key 4 fastened by screws to the key groove 2k is aligned with the key groove 2k, and the set bolts 6 (here, four places) are inserted into the mounting bolt holes 2g. Outer circumference of end face 11a of cylinder 11 and contact face 2c
Is completed by tightening without gaps. When this clamping, the upper rim 1q is a spigot 2d depth _{H 1} of the screw touch bushing 1 from the upper abutment surface 2q of the upper spigot 2j, than the height _{H 1} of the end face 11a from 0.05 to 0.
Since it is 1 mm deeper, it protrudes more than the contact surface 2q, and the end surface 11a and the upper peripheral edge 1q are in strong contact. The contact surface 2q is practically non-contact, and the contact surfaces 1i and 2i are in surface contact with each other, and a strong frictional contact is obtained by the interference fit between the upper spigot 2j and the upper fitting portion 1j. To check the該締with state, the convex portion 1e from the lower spigot 2h total height T ₂ of the screw touch bush 1 - since projecting by a length inlaid T _{1 =} amount of protrusion H _2, the protrusion amount H ₂ By measuring, it can be confirmed whether the fitting is sufficient.

Further, the set bolt 7 (in this case, the mounting bolt hole 2g is inserted into the mounting bolt hole 2g while the projection 1e and the spigot 9h of the mounting swash plate 9a are aligned with the key groove 9k fixed to the heating cylinder 11. The connection is completed by inserting (four places) and tightening sequentially.

At the time of disassembly, the heating cylinder 11 is separated from the first connection block 3 by loosening the set bolt 7 and separating it from the second connection block 9 and then loosening the set bolt 6. The abutment surface 2c side Place the tool post which is a large hole than the diameter d ₂ of the upper spigot 2j, placed down the abutment surface 2c so as to be able to screw the touch bush 1 drops into the hole Thus, the protrusion 1e on the upper side can be pushed out by hitting with a tool such as a hammer, and can be replaced.

In addition, when the screw 12 advances and closes the passage 1a during assembly use, the contact surface 1m having a small area formed on the surface of the screw touch bush 1 is formed.
, The screw 12 comes into contact, so that it can be closed with a small pressure. Then, the end surface 11a of the heating cylinder 11 comes into surface contact with the upper peripheral edge 1q, and the contact surfaces 1i, 2i are pressed against each other so as to press each other. 1j, the frictional contact area is large due to the tight fit.
2 when the screw 1 is not completely stopped
2, the screw touch bush 1 is fixed stably without instantaneous rotation. Furthermore, when the screw 12 starts rotating and starts melting the resin from the state where the screw 12 closes the passage 1a, the instant contact surface 1m is rubbed, but the flight on the tip side of the screw 12, that is, The screw 1 that was in contact with the contact surface 1m due to the pressure generated by the rotation of the molten resin in the metering zone
2 immediately separates from the contact surface 1m, and keeps the screw touch bush 1 stable without rotating it.

The first connecting block 3 can be divided into the screw touch bush 1 and the connecting flange 2 when viewed from the working surface, so that the influence of harmful gas on steel generated when the resin is melted is reduced. In addition to the corrosion resistance, heat resistance and abrasion resistance of the screw touch bush 1, the steel parts are selected in consideration of heat resistance and abrasion resistance, and the corrosion resistance, heat resistance and abrasion resistance to be determined by heat treatment. Can improve the sex. Screw touch bush 1 with small insert
Has a simplified processing shape, which facilitates production. In the present invention, alloy tool steel or structural alloy steel is used, but the corrosion resistance, heat resistance, and wear resistance as described above are used. By using a ceramic alloy made of a metal powder mainly composed of, it is possible to improve the durability with respect to the service life.

In addition, the purpose of the connecting flange 2 is to close the front of the heating cylinder 11 like a lid and to connect with the injection side 20 via the second connecting block 9 to be integrated. By selecting a steel material that has heat resistance and corrosion resistance, its characteristics can be utilized and the outer diameter (shape) is not cut into a square shape. The portion where the hole 5f approaches the side in the outer periphery is eliminated, and there is no fear that a crack may occur from the approaching portion.

Further, since the screw touch bush 1 improves compatibility and can utilize the characteristics of the steel used as described above, the service life of the screw touch bush 1 is also extended, and overall The cost reduction by dividing the first connection block 3 into the screw touch bush 1 and the connection flange 2 is considerably large. And
The screw touch bush 1 is replaced by a set bolt 6,
7 can be replaced by removing them, so that there is no problem in security, and each contact surface, ie, the convex portion 11a, the upper peripheral edge 1c, the contact surfaces 1i, 2i, and the convex portion 1e.
And the spigot 9h are firmly adhered to each other in a strong contact, so that the possibility that molten resin enters the corresponding contact surface and breaks the set bolts 6 and 7 can be eliminated.

[0034]

As described above, while the first connecting block is conventionally formed as a single unit as a whole, the first connecting block is divided into a screw touch bush and a connecting flange, and the connecting flange is tightened. Since the touch bush is adapted to be fitted to the connection flange, the compatibility of the screw touch bush is improved, and furthermore, by tightening the connection flange, the screw touch bush comes into strong frictional contact within the connection flange. It is fixed without using a fixing tool such as a bolt or a key, and the screw touch bush does not crack when tightened. Therefore, replacement at the site where the machine is installed can be easily performed.

Since the screw touch bush is made of a small insert, the material of the screw touch bush can be selected from steel excellent in heat resistance, corrosion resistance and abrasion resistance suitable for the application, and suitable heat treatment can be performed. In addition, it is possible to improve the characteristics by heat treatment and corrosion resistance required for the connection flange, and to improve the characteristics by heat treatment. The performance as a heating cylinder of the machine is improved.

[Brief description of the drawings]

FIG. 1 is a partially assembled plan view according to the present invention.

FIG. 2 is a sectional view of Embodiment 1 of the screw touch bush according to the present invention.

FIG. 3 is a sectional view of a screw touch bush according to a second embodiment of the present invention.

FIG. 4 shows the connecting flange of the present invention taken along the line X-O- in FIG.
FIG.

FIG. 5 is a bottom view of the connection flange in FIG. 4;

FIG. 6 is a partially assembled plan view of a conventional example.

FIG. 7 is a cross-sectional view of a first connection block in a conventional example, taken along line XX in FIG. 8;

FIG. 8 is a bottom view of the first connection block in FIG. 7;

[Explanation of symbols]

Reference Signs List 1 screw touch bush 1a passage (opening) 1h lower fitting portion 1i abutment surface 1j upper fitting portion 1m contact surface 1n play surface 1r play surface 1q upper peripheral edge 2 connecting flange 2d spigot 2f mounting bolt hole 2g mounting bolt hole 2h lower portion Spigot 2i Contact surface 2j Upper spigot 2k Keyway 3 First connecting block 9 Second connecting block 9g Passage 10 Plasticizing section 11 Heating cylinder 11a End face 12 Screw 14 Plasticizing chamber 20 Injection section 23 Injection cylinder 24 Injection plunger 25 Injection chamber 30 passage R (play) angle D ₁ inner diameter (diameter) of heating cylinder 11 d ₂ diameter of upper spigot 2j (1a, 9g, 30 communicating passages)

Claims (4)

(57) [Claims] 1. A plasticizing section which rotates a screw in a heating cylinder to plasticize a synthetic resin material, and an injection section which advances and retreats an injection plunger into an injection cylinder to inject the plasticized material from a nozzle. The heating cylinder having a first connection block on the plasticizing part side and the injection cylinder having a second connection block on the injection part side are connected to each other by connecting the two connection blocks to each other. And the molten material is circulated from the plasticizing section to the injection section. At the time of injection, the screw is advanced so that the tip of the screw comes into contact with the first connection block to close the passage. In the heating cylinder for a pre-plastic injection molding machine described above, the first connection block is constituted by a connection flange and a screw touch bush, and the connection flange is formed by a flat disk. In addition, an upper spigot having a diameter larger than the inner diameter of the heating cylinder is provided at the center of the connection flange, and the screw touch bush having a contact surface with which a part of the screw tip comes into contact with the spigot is provided. By inserting and fitting, the connecting flange is fastened and fixed while abutting the end face of the heating cylinder and the upper peripheral edge, whereby the upper peripheral edge is closely contacted and fixed to the end face, and the lower fitting portion of the screw touch bush is fixed. A heating cylinder for a pre-plastic injection molding machine, wherein the heating cylinder protrudes from a lower spigot of the connection flange to enable connection with the second connection block. 2. The screw touch bush penetrates a resin passage at the center, and a contact surface around the passage hole where a part of the screw tip comes into contact, and a play at an outer periphery thereof having an angle larger than the screw tip. Surface, and the upper peripheral edge having a diameter larger than the inner diameter of the heating cylinder is formed in a plane, and the lower fitting portion is formed to be integrally formed in a substantially convex shape in a side view. The heating cylinder for a pre-plastic injection molding machine according to claim 1. 3. The disc-shaped connecting flange penetrates a lower spigot at the center of the disc, and an upper spigot and a spigot for fitting and positioning with an end face of a heating cylinder are sequentially formed in a stepped shape. And a mounting bolt hole for connection with the second connection block is drilled,
The heating cylinder for a pre-plastic injection molding machine according to claim 1, wherein one keyway is formed on an outer periphery of the disc-shaped connecting flange. 4. The screw touch bush is made of alloy tool steel or structural alloy steel by quenching or nitriding to have the same hardness as the screw, and the connecting flange is a special purpose alloy steel having heat resistance and corrosion resistance. That formed,
Claim 1 or 2 or 3 pre-plasticization type injection molding machine heated cylinder wherein. that's all