Metering injection mechanism and injection molding equipment

Abstract

According to the metering injection mechanism and the injection molding equipment, a downward pressing mechanism is additionally arranged in a feeding cylinder, and a pushing rod is matched with the downward pressing mechanism to extrude injection molding raw materials towards the output end of an injection material pipe, so that glass fibers are prevented from being broken due to spiral stirring of the injection molding raw materials; the structural strength of an injection molding finished product is improved, the output dosage of injection molding raw materials is accurate, and the production and processing efficiency is higher; injection molding raw materials meeting multiple times of injection molding are injected into the material supply cylinder, the injection molding raw materials fill the internal pipeline of the injection material pipe, and then the injection cylinder drives the material pushing rod to move at a first thrust value so as to exhaust gas among the injection molding raw materials from the exhaust structure; and the injection cylinder drives the material pushing rod to move by the preset stroke or the preset duration at the second thrust value larger than the first thrust value, then the injection cylinder repeatedly acts at the second thrust value to quantitatively extrude the injection molding raw materials for multiple times, and multiple injections are carried out after one-time feeding is met so as to improve the injection molding machining efficiency.

Description

TECHNICAL FIELD

[0001] The utility model relates to injection molding production technical field especially relates to a kind of metering injection mechanism and injection molding equipment. BACKGROUND

[0002] When producing injection molding products, the raw materials required for injection molding are usually injected into the mold for molding by using injection mechanism. The current injection mechanism uses moving cylinder to drive the whole injection mechanism to move towards the direction of the mold to press against the mold, and then uses motor to rotate to drive the screw to rotate. The outside of the screw is sleeved with a material pipe along its length direction. The upper side of the material pipe is provided with a feed inlet for inputting injection molding raw materials. With the rotation of the screw, the screw thread on the screw can push the injection molding raw materials into the mold.

[0003] The screw thread on the screw has the functions of stirring, pushing and extruding, so it is widely used in the injection mechanism of the current injection molding equipment and has good effect. However, in order to improve the mechanical strength of the parts, some existing injection molding products often add glass fiber to the plastic. The glass fiber is in the form of long strip and silk. When the screw rotates, the glass fiber will be cut or twisted, which will reduce the strength of the plastic finished product.

[0004] In addition, in the injection mechanism using screw, the screw rotates a certain number of turns to realize the feeding action, and then the fed part is extruded. Due to the different densities of injection molding raw materials and the unstable extrusion degree of injection molding raw materials when the screw rotates, the quality of the product formed by each injection molding is not stable. Moreover, the screw has certain delay characteristics in pushing material, which reduces the working efficiency. INVENTION CONTENTS

[0005] The utility model aims at solving one of the technical problems existing in the prior art. Therefore, one of the purposes of the utility model is to provide a metering injection mechanism which can avoid stirring injection molding raw materials by screw to improve the strength of finished product, accurately output dose and has high working efficiency. The second purpose is to provide an injection molding equipment using the above metering injection mechanism.

[0006] According to the metering injection mechanism of the first aspect of the utility model, the installation seat, the material cylinder main body, the moving cylinder, the feeding pipe and the push rod are arranged in the above manner. When the injection molding raw materials are fed into the injection material pipe, the push rod is driven to move close to the injection mold to output the injection molding raw materials.

[0007] The metering injection mechanism has at least the following beneficial effects:

[0008] The metering injection mechanism with the above structure increases the pressing mechanism in the feeding pipeline, and the pushing rod cooperates with the pressing mechanism to extrude the injection material towards the output end of the injection material pipe, so that the glass fiber can be prevented from being broken by screwing and stirring the injection material, the structural strength of the injection product is improved, and compared with the traditional screw rod mode, the output dose of the injection material is accurate, and the production and processing efficiency is higher.

[0009] In some embodiments of the utility model, two parallel slide rails are arranged on the mounting seat, the extension direction of the slide rail is consistent with the sliding direction of the material cylinder main body, the material cylinder main body has a supporting leg slider that slides on the two slide rails respectively, the injection material pipe is horizontally arranged at the middle position between the two slide rails, and the feeding pipeline is vertically arranged at the middle position between the two slide rails.

[0010] In some embodiments of the utility model, supporting frames are arranged on the two sides of the material cylinder main body respectively corresponding to the two slide rails, the supporting leg slider is mounted on the supporting frame, the first mounting channel for mounting the injection material pipe is horizontally arranged through the material cylinder main body, the material cylinder main body is provided with the second mounting channel that is in communication with the first mounting channel and extends upward, the feeding pipeline is mounted on the second mounting channel, and the first mounting channel and the second mounting channel are located at the middle position between the two supporting frames.

[0011] In some embodiments of the utility model, the second mounting channel comprises a feeding port in communication with the upper side of the first mounting channel and a conical flow guide surface formed on the outer peripheral edge of the feeding port and having a wide upper part and a narrow lower part, the feeding port is in the shape of a long strip parallel to the first mounting channel, and the lower end of the feeding pipeline is sealingly connected to the outer peripheral edge of the conical flow guide surface.

[0012] In some embodiments of the utility model, the pressing mechanism comprises two first piston cylinders arranged vertically upward, the cylinder bodies of the two first piston cylinders are fixedly connected to the opposite sides of the second mounting channel respectively, a lifting cross beam is connected between the upper ends of the output rods of the two first piston cylinders, the middle part of the lifting cross beam is provided with a pressing rod that extends downward into the feeding pipeline, the pressing rod is provided with a first sealing plug that cooperates with the inner peripheral wall of the feeding pipeline, and the first sealing plug is a conical body that is matched with the conical flow guide surface and has a wide upper part and a narrow lower part.

[0013] In some embodiments of this utility model, the material cylinder body is provided with a third installation channel on each side of the first installation channel. The third installation channel is parallel to the slide rail and located directly above the corresponding support frame. The cylinder bodies of the two injection cylinders are respectively installed in the two third installation channels. A gantry frame is connected between the output rods of the two injection cylinders extending out of one end of the material cylinder body. The two sides of the gantry frame are respectively slidably arranged on the two slide rails. The end of the push rod away from the injection tube is fixedly connected to the middle of the gantry frame.

[0014] In some embodiments of this utility model, one end of the injection tube has a discharge nozzle extending out of the material cylinder body, the discharge nozzle being used to connect to the input port of the injection mold, and the other end of the injection tube is provided with a scraper sleeve that can contact the outer peripheral wall of the push rod to prevent the injection molding material from overflowing.

[0015] In some embodiments of this utility model, the outer peripheral wall of the push rod is recessed in a radial direction to form a spiral groove, the spiral groove extends along the length of the push rod, and the spiral groove and the scraper sleeve can define a spiral gas channel that can only allow gas to be discharged outward.

[0016] An injection molding device according to a second aspect of the present invention includes a metering injection mechanism of any of the above-described technical solutions. This injection molding device can avoid breaking glass fibers due to spiral stirring of the injection molding material, thereby improving the structural strength of the injection-molded product. Furthermore, compared to the traditional screw method, it provides more precise dosage of the injection molding material, resulting in higher production efficiency.

[0017] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0019] Figure 1 This is a schematic diagram of the structure of one embodiment of the metering injection mechanism of this utility model;

[0020] Figure 2 for Figure 1 A structural schematic diagram from another perspective of the embodiment;

[0021] Figure 3 for Figure 1 A cross-sectional schematic diagram of an embodiment;

[0022] Figure 4 for Figure 1A schematic view of the structure of the cylinder body of the embodiment.

[0023] Reference signs:

[0024] mounting seat 100; slide rail 110; cylinder body 200; foot slider 210; first mounting channel 220; second mounting channel 230; feeding port 231; conical flow guide surface 232; third mounting channel 240; support frame 250; injection cylinder 300; discharge nozzle 310; scraping sleeve 320; moving cylinder 400; feeding pipe 500; pressing mechanism 600; first piston cylinder 610; lifting cross beam 620; pressing rod 630; first sealing plug 640; pushing rod 700; injection cylinder 710; gantry 720. DETAILED DESCRIPTION

[0025] The embodiments of the present application are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application.

[0026] In the description of the present application, it should be understood that, in relation to the orientation description, for example, the orientation or position relationship indicated by the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0027] In the description of the present application, the meaning of several is one or more, and the meaning of multiple is two or more, greater than, less than, more than, etc. are understood as not including the number, above, below, etc. are understood as including the number. If it is described as first, second, it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the sequence of indicated technical features.

[0028] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For ordinary skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0029] Referring to Figures 1 to 4 The utility model discloses a kind of metering injection mechanism, comprising: mounting seat 100;Material cylinder main body 200, slidingly disposed in the mounting seat 100, material cylinder main body 200 is equipped with the injection material pipe 300 extending along its sliding direction;Moving cylinder 400, one end is connected to the material cylinder main body 200, the other end is fixedly installed on injection mold, for driving the output end of the injection material pipe 300 to be tightly in the input port of injection mold;Feed pipe 500, vertically in the upper side wall of the injection material pipe 300 and communicate the inside of the injection material pipe 300;Pressing mechanism 600, lifting is disposed in the feed pipe 500, and the injection raw material in the feed pipe 500 is pressed into the injection material pipe 300 downwards;Pushing rod 700, one end of the pushing rod 700 is slidingly disposed in the injection material pipe 300, the other end of the pushing rod 700 is connected with the injection cylinder 710 that drives it to move close to the injection mold to output injection raw material.

[0030] The metering injection mechanism of above structure increases pressing mechanism 600 in feed pipe 500, and injection raw material is extruded towards the output end of injection material pipe 300 using pushing rod 700 cooperation pressing mechanism 600, so as to avoid that glass fiber is broken by screwing stirring injection raw material, and the structural strength of injection product is improved, and compared with the traditional mode of screw, the output dose of injection raw material is accurate, and production and processing efficiency is higher.

[0031] Referring to Figure 1 And Figure 2 In some embodiments of the utility model, in order to realize that material cylinder main body 200 slides stably relative to mounting seat 100, two parallelly arranged slide rails 110 are arranged on the mounting seat 100, the extension direction of the slide rail 110 is consistent with the sliding direction of the material cylinder main body 200, the material cylinder main body 200 has supporting foot sliding block 210 that slides on two slide rails 110 respectively, the injection material pipe 300 is horizontally arranged at the intermediate position between two slide rails 110, and the feed pipe 500 is vertically arranged at the intermediate position between two slide rails 110.It can be understood that pressing mechanism 600 acts vertically downwards on feed pipe 500 to push injection raw material into injection material pipe 300, and the above layout of feed pipe 500 and injection material pipe 300 is beneficial to force balance, and can avoid the situation of tilting.

[0032] Referring to Figure 1 And Figure 4In some embodiments of the utility model, two sides of material cylinder main body 200 respectively correspond two slide rails 110 are provided with support frame 250, foot sliding block 210 is installed to support frame 250, first installation passage 220 for installing injection material pipe 300 is horizontally arranged in material cylinder main body 200, material cylinder main body 200 is equipped with the second installation passage 230 that is communicated with first installation passage 220 and extends upwards, feed pipe 500 is installed to second installation passage 230, first installation passage 220, second installation passage 230 are all located in the intermediate position between two support frames 250. Specifically, first installation passage 220 and second installation passage 230 of material cylinder main body 200 are integrally formed in material cylinder main body 200, injection material pipe 300, feed pipe 500 are installed on first installation passage 220 and second installation passage 230 respectively, which facilitates the production and manufacture of metering injection mechanism.

[0033] Referring to Figure 3 And Figure 4 In some embodiments of the utility model, the second installation passage 230 includes the feed inlet 231 that is communicated with the upper side of the first installation passage 220 and the conical flow guide surface 232 that is formed in the outer peripheral edge of the feed inlet 231 and is wide at the top and narrow at the bottom, the feed inlet 231 is in a long strip shape parallel to the first installation passage 220, and the lower end of the feed pipe 500 is sealingly connected to the outer peripheral edge of the conical flow guide surface 232. It can be understood that when the injection material in the feed pipe 500 is pushed downward by the downward pressing mechanism 600, the injection material can enter the feed inlet 231 along the conical flow guide surface 232, which can reduce the risk of jamming. Moreover, since the feed inlet 231 is parallel to the first installation passage 220, the injection material entering the feed inlet 231 from the conical flow guide surface 232 can flow along the length direction of the injection material pipe 300, further improving the smoothness of the injection material supply.

[0034] Referring to Figures 1 to 3In some embodiments of the utility model, the lower pressure mechanism 600 includes two vertical upwardly arranged first piston cylinder 610, two first piston cylinder 610's cylinder body is fixedly connected on the opposite sides of second installation channel 230 respectively, two first piston cylinder 610's output rod's upper end is connected with the lifting crossbeam 620 between, the middle part of lifting crossbeam 620 is equipped with the lower pressure rod 630 that goes down into the feed pipe 500, be equipped with the first sealing plug 640 that cooperates with the inner peripheral wall of feed pipe 500 on lower pressure rod 630, first sealing plug 640 is the cone that is matched with conical flow guide surface 232 and is wide at top narrow, it can be understood that, when the output rod of two first piston cylinder 610 is retracted, drive lifting crossbeam 620 to move down, thereby drive the first sealing plug 640 of lower pressure rod 630 moves down along the inner peripheral wall of feed pipe 500, until the outer peripheral wall of first sealing plug 640 is tightly matched with conical flow guide surface 232, in turn, push the injection material to enter the injection material pipe 300 down, and form good sealing effect. Because the force that the injection cylinder 710 drive pusher rod 700 extrudes injection material is larger, lower pressure mechanism 600 must keep larger lower pressure to ensure that injection material does not overflow, and the driving mode that two first piston cylinder 610 and lifting crossbeam 620 cooperate can reach good driving force effect.

[0035] Referring to Figure 2 And Figure 4 In some embodiments of the utility model, the material cylinder main body 200 is equipped with a third installation channel 240 on the two sides of first installation channel 220 respectively, the third installation channel 240 is parallel to the slide rail 110 and is located above the corresponding support frame 250, the cylinder body of two injection cylinders 710 is installed in two third installation channels 240 respectively, and the output rod of two injection cylinders 710 is connected with a gantry 720 between one end of the material cylinder main body 200, the two sides of the gantry 720 are respectively arranged on two slide rails 110, and the end of the pusher rod 700 away from the injection material pipe 300 is fixedly connected to the middle part of the gantry 720. It can be understood that the third installation channel 240 is used for installing the injection cylinder 710, and the two injection cylinders 710 are distributed on the two sides of the pusher rod 700, which is conducive to the pusher rod 700 receiving the axial thrust, and can avoid the problem of large volume caused by arranging the injection cylinder 710 along the extension direction of the pusher rod 700.

[0036] Referring to Figure 3In some embodiments of the utility model, one end of injection material pipe 300 has material outlet 310 which extends from material cylinder main body 200, material outlet 310 is used for connecting the input port of injection mold, the other end of injection material pipe 300 is internally provided with scraping sleeve 320 which can contact with the outer peripheral wall of pushing material rod 700 to prevent the overflow of injection raw material. It can be understood that the relative sliding between pushing material rod 700 and injection material pipe 300 can cause the overflow of injection raw material, and the setting of scraping sleeve 320 can solve or improve this situation.

[0037] In some embodiments of the utility model, the outer peripheral wall of pushing material rod 700 is recessed along its radial direction to form spiral groove, spiral groove is arranged along the length direction of pushing material rod 700, spiral groove and scraping sleeve 320 can define spiral gas channel which can only discharge gas outward. It needs to be explained that when pushing material rod 700 moves towards the direction of material outlet 310, injection raw material is extruded and discharged from material outlet 310, at the same time, since the inside of injection material pipe 300 is in sealed state, the gas between injection raw material cannot be discharged, leading to the product of injection molding is easy to produce bubbles, using spiral gas channel can make the gas discharge outward along the direction of spiral gas channel away from material outlet 310, and the shape of spiral gas channel makes it difficult for injection raw material to follow the gas to discharge, that is, spiral gas channel can only discharge gas but not injection raw material.

[0038] The injection tube 300 of the metering injection mechanism of any of the above technical solutions is communicated with an exhaust structure, and the working principle thereof comprises the following steps: the moving cylinder 400 drives the output end of the injection tube 300 to abut against the input port of the injection mold, injection material is injected into the feeding pipeline 500, and the quantity of the injection material meets the multiple injection of the injection mold; the injection cylinder 710 drives the material pushing rod 700 to move away from the injection mold so that the internal pipeline of the injection tube 300 is communicated with the feeding pipeline 500; the lower pressing mechanism 600 drives the injection material to fill the internal pipeline of the injection tube 300; then the injection cylinder 710 drives the material pushing rod 700 to move close to the injection mold at a first pushing force value, so that the gas between the injection materials in the injection tube 300 is exhausted outward from the exhaust structure; then the injection cylinder 710 drives the material pushing rod 700 to move close to the injection mold at a second pushing force value for a preset stroke or a preset time length, the second pushing force value is greater than the first pushing force value; and then the injection cylinder 710 repeatedly drives the material pushing rod 700 to move close to the injection mold at the second pushing force value for a preset stroke or a preset time length, so that the injection material is extruded multiple times in a quantitative manner. The above injection material extrusion method can meet the multiple injection after one-time feeding, further improve the efficiency of injection molding, can avoid the broken glass fiber caused by the spiral stirring of the injection material, improve the structural strength of the injection product, and compared with the traditional screw mode, the output dose of the injection material is accurate, and the quality stability of the injection product is improved.

[0039] The exhaust structure is the spiral gas channel in the above embodiment, the size of the first pushing force value can be adjusted according to the softness and hardness of different injection materials, for example, the gas gap of the relatively soft injection material is generally large, at this time, the first pushing force value needs to be appropriately increased, the gas gap of the relatively hard injection material is generally small, at this time, the first pushing force value needs to be appropriately reduced. In some embodiments of the utility model, a gas pressure sensor can also be connected to the end of the spiral gas channel, after the injection cylinder 710 drives the material pushing rod 700 to press on the injection material for a certain time length at the first pushing force value, if the gas pressure sensor detects that the exhausted gas is almost 0, the first pushing force value can be set as a set value, if the gas pressure sensor detects that the exhausted gas is greater than a certain flow, the first pushing force value needs to be increased, so as to meet the exhaust condition, and the internal structure of the injection material is not easily damaged due to excessive pressure.

[0040] The utility model also discloses an injection equipment, including the metering injection mechanism of any of the above technical solutions. The injection equipment can avoid the broken glass fiber caused by the spiral stirring of the injection material, improve the structural strength of the injection product, and compared with the traditional screw mode, the output dose of the injection material is accurate, and the production and processing efficiency is higher.

[0041] Any technical features in the above embodiments can be combined, and for the sake of brevity, not all possible combinations are described above, however, it should be understood that the scope of the specification includes all possible combinations.

[0042] Although the embodiments of the present application have been shown and described, it should be understood by those ordinary skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. A metered dose injection mechanism characterized by, The utility model relates to a kind of metering injection mechanisms comprising: Mounting seat (100); Material cylinder body (200), slidingly disposed in the mounting seat (100), the material cylinder body (200) is equipped with injection material pipe (300) extending along its sliding direction; Moving cylinder (400), one end is connected to the material cylinder body (200), the other end is fixedly installed on injection mold, for driving the output end of the injection material pipe (300) to be tightly pressed in the input port of the injection mold; Feed pipe (500), vertically disposed in the upper side wall of the injection material pipe (300) and communicated with the inside of the injection material pipe (300); Pressing mechanism (600), liftingly disposed in the feed pipe (500), injection raw material in the feed pipe (500) is pressed downwards into the injection material pipe (300); Pushing rod (700), one end of the pushing rod (700) is slidably disposed in the injection material pipe (300), the other end of the pushing rod (700) is connected with shooting cylinder (710) for driving it to move close to the injection mold to output injection raw material.

2. The metering injection mechanism according to claim 1, wherein: The mounting seat (100) is provided with two parallel sliding rails (110), the extension direction of the sliding rails (110) is consistent with the sliding direction of the material cylinder body (200), the material cylinder body (200) has foot sliding blocks (210) sliding on the two sliding rails (110) respectively, the injection material pipe (300) is horizontally disposed at the middle position between the two sliding rails (110), and the feed pipe (500) is vertically disposed at the middle position between the two sliding rails (110).

3. The metering injection mechanism according to claim 2, wherein: The material cylinder body (200) is provided with support frames (250) corresponding to the two sliding rails (110) respectively on both sides, the foot sliding blocks (210) are mounted on the support frames (250), the material cylinder body (200) is horizontally provided with a first mounting channel (220) for mounting the injection material pipe (300), the material cylinder body (200) is provided with a second mounting channel (230) extending upward and communicating with the first mounting channel (220), the feed pipe (500) is mounted on the second mounting channel (230), and the first mounting channel (220) and the second mounting channel (230) are located at the middle position between the two support frames (250).

4. The metering injection mechanism according to claim 3, wherein: The second mounting channel (230) comprises a feed port (231) communicating with the upper side of the first mounting channel (220) and a conical flow guide surface (232) shaped on the outer peripheral edge of the feed port (231) and gradually narrowing from top to bottom, the feed port (231) is in the shape of a long strip parallel to the first mounting channel (220), and the lower end of the feed pipe (500) is sealingly connected to the outer peripheral edge of the conical flow guide surface (232).

5. The metering injection mechanism according to claim 4, characterized in that: the pressing mechanism (600) comprises two vertically upward arranged first piston cylinders (610), cylinder bodies of the two first piston cylinders (610) are fixedly connected on opposite sides of the second mounting channel (230), upper ends of output rods of the two first piston cylinders (610) are connected with a lifting cross beam (620), a middle part of the lifting cross beam (620) is provided with a pressing rod (630) downwardly extending into the feeding pipeline (500), the pressing rod (630) is provided with a first sealing plug (640) matched with an inner circumferential wall of the feeding pipeline (500), the first sealing plug (640) is a conical body matched with the conical flow guide surface (232) and having a width gradually decreasing from top to bottom.

6. The metering injection mechanism according to claim 3, characterized in that: the material cylinder body (200) is provided with a third mounting channel (240) on each side of the first mounting channel (220), the third mounting channel (240) is parallel to the slide rail (110) and located directly above the corresponding support frame (250), cylinder bodies of two injection cylinders (710) are respectively mounted in the two third mounting channels (240), output rods of the two injection cylinders (710) are connected with a gantry (720) between one end of the material cylinder body (200) extending out of the material cylinder body (200), the gantry (720) is respectively slidably arranged on the two slide rails (110), and the pushing rod (700) is fixedly connected to a middle part of the gantry (720) away from the injection material pipe (300).

7. The metering injection mechanism according to claim 1, characterized in that: one end of the injection material pipe (300) has a discharging nozzle (310) extending out of the material cylinder body (200), the discharging nozzle (310) is used for connecting an input port of an injection mold, and the other end of the injection material pipe (300) is internally provided with a scraping sleeve (320) capable of contacting an outer circumferential wall of the pushing rod (700) to prevent overflow of injection materials.

8. The metering injection mechanism according to claim 7, characterized in that: the outer circumferential wall of the pushing rod (700) is recessed along a radial direction to form a spiral groove, the spiral groove extends along a length direction of the pushing rod (700), and the spiral groove and the scraping sleeve (320) can define a spiral gas channel only allowing gas to be discharged outward.

9. An injection molding apparatus characterized by comprising: The metering injection mechanism according to any one of claims 1-8.

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