Thermal insulation sheath injection molding system
By using the slow rotation of the middle sleeve in the thermally insulated sheath injection molding system to drive the spiral conveying blades to preheat the rubber raw materials, the problems of waste of heat energy and unpreheated rubber raw materials are solved, and the injection molding efficiency and molding pass rate are improved.
Patent Information
- Application Number
- CN202510481623.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-17
- Publication Date
- 2025-07-11
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
In the prior art, the heat insulation sheathing casing is seriously wasted during molding and water cooling, and the rubber raw materials are directly heated and melted without preheating, resulting in low injection molding efficiency.
By controlling the slow rotation of the sleeve, the spiral conveying blades are driven to rotate slowly in the preheating chamber, and the high-temperature heat exchange between the rubber raw materials and the injection mold is achieved, and the preheating of the rubber raw materials and the initial cooling of the inner sheath of the molding chamber is completed.
It improves the heating and melting efficiency of rubber raw materials, reduces heat energy waste, and improves the overall efficiency and molding qualification rate of sheath injection molding.
Smart Images
Figure CN120287515A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of injection molding equipment, and more specifically, it relates to a heat insulation sheath injection molding system. Background Art
[0002] Injection molding, also known as injection molding, is a molding method that combines injection and molding. The advantages of the injection molding method are high production speed, high efficiency, automated operation, and the ability to form complex parts. Injection molding is suitable for mass production and the molding processing of complex-shaped products.
[0003] In the production of heat insulation sleeves in the intelligent manufacturing equipment industry, injection molding is often used to process heat insulation sleeves. Usually, a hot melt plastic is extruded into a mold by an injection device, formed in the mold, and then pulled out of the mold. The temperature of the formed sleeve is relatively high, and water cooling is required in the subsequent process.
[0004] However, a large amount of heat energy is generated before the sleeve is formed in the mold and before water cooling. Direct water cooling in the subsequent process causes waste of heat energy. At the same time, in the prior art, the rubber raw material is not preheated, and the rubber raw material is directly added to an electric heating barrel for heating and melting. Therefore, it is very necessary to utilize the heat energy inside the injection mold to preheat the rubber raw material. Summary of the Invention
[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a heat insulation sheath injection molding system. By controlling the slow rotation of the middle sleeve to drive the spiral conveying blade to slowly rotate in the preheating chamber, the slow conveying of the rubber raw material in the preheating chamber is realized, and heat exchange is carried out with the high temperature inside the injection mold, which not only realizes the preliminary cooling of the sheath inside the molding cavity, but also completes the preheating of the rubber raw material, improves the heating and melting efficiency of the subsequent rubber raw material, and thus improves the injection molding efficiency of the sheath.
[0006] To achieve the above purpose, the present invention provides the following technical solutions:
[0007] A heat-insulating sheath injection molding system includes a screw injection molding device and an injection mold fixedly installed at the output end of the screw injection molding device; the injection mold includes a front sleeve, a middle sleeve, and a rear sleeve arranged coaxially; both ends of the middle sleeve are rotatably matched with the front sleeve and the rear sleeve respectively; the front sleeve includes an outer tube, an inner tube, and a core shaft tube arranged coaxially; a forming cavity is formed between the core shaft tube and the inner tube; a preheating cavity is formed between the inner tube and the outer tube; a spiral conveying blade placed inside the preheating cavity is fixedly installed on the outer peripheral side of the middle sleeve; a batching part is fixedly installed beside the screw injection molding device; the batching part includes a support frame; a fixed ring coaxially arranged is fixedly installed at the top of the support frame; an electric heating barrel is communicated and installed at the bottom of one fixed ring; a hopper is communicated and installed at the top of the other fixed ring; a material changing frame is rotatably arranged between the two fixed rings.
[0008] The present invention is further arranged as follows: a flange is fixed at one end of the inner tube; the output end of the screw injection molding device is fixedly connected with the flange through fastening bolts; inner annular grooves are respectively opened on the inner peripheral side of the inner tube and the inner peripheral side of the rear sleeve; annular plates rotatably matched with the corresponding inner annular grooves are respectively fixed at both ends of the middle sleeve; a sealing ring is fixedly installed on the outer peripheral side of the annular plate; a sealing groove adapted to the sealing ring is opened on the inner peripheral side of the inner annular groove.
[0009] The present invention is further arranged as follows: toothed rings are respectively fixed on the outer peripheral sides of the middle sleeve and the rear sleeve; two first motors are fixedly installed on the side of the support frame; first gears meshing with the corresponding toothed rings are respectively fixed at the output ends of the two first motors.
[0010] The present invention is further arranged as follows: a second motor is fixedly installed on the side of the support frame; a second gear is fixed at the output end of the second motor; the material changing frame includes a connecting plate; rotating rings rotatably matched with the corresponding fixed rings are respectively fixed at both ends of the connecting plate; a toothed ring meshing with the second gear is fixedly installed on the peripheral side of the connecting plate; a first heat preservation barrel and a second heat preservation barrel are respectively communicated and arranged on the peripheral sides of the two rotating rings; the bottoms of the first heat preservation barrel and the second heat preservation barrel are both opened and are slidably adapted to the inner peripheral sides of the corresponding fixed rings; avoiding openings are symmetrically opened on the peripheral side of the outer tube near its two ends.
[0011] The present invention is further arranged as follows: a lower discharge port is opened at the bottom of one fixed ring; an upper discharge port is opened at the top of the other fixed ring; an outer annular groove is opened on the outer peripheral side of the fixed ring; annular baffles are rotatably arranged in both outer annular grooves; an upper discharge hole is opened at the top of one annular baffle; a lower discharge hole is opened at the bottom of the other annular baffle.
[0012] The present invention is further configured such that: an arc-shaped toothed plate is fixed to the outer peripheral side surface of the annular baffle; a third motor is fixedly installed on the side surface of the support frame; a connecting shaft is fixed to the output end of the third motor; two groups of gears are fixed to the peripheral side surface of the connecting shaft; the two gears are respectively meshed and matched with the corresponding arc-shaped toothed plates.
[0013] The present invention is further configured such that: a filter plate is fixed to the end of the inner tube; an annular filter net is fixed to the end of the outer tube; the core shaft tube, the filter plate, and the inside of the inner tube are all provided with a hollow structure; the inside of the core shaft tube is communicated with the inside of the inner tube through the filter plate; a plurality of first ventilation holes communicated with the preheating cavity are uniformly formed on the outer peripheral side surface of the inner tube; a plurality of second ventilation holes are uniformly formed on the inner peripheral side surface of the core shaft tube; a plurality of air permeable holes are uniformly formed on the spiral conveying blade.
[0014] The present invention is further configured such that: an annular seat is fixed to the end of the core shaft tube; an air extractor is fixedly installed on the annular seat; a controller is fixedly installed on the support frame; the output end of the controller is electrically connected to the air extractor, the first motor, the second motor, and the third motor respectively; a delivery pump is arranged inside the electric heating barrel; the output end of the delivery pump is connected to the feed inlet of the screw injection molding device through a delivery pipe.
[0015] The advantages of the present invention are:
[0016] 1. By controlling the middle sleeve and the rear sleeve to rotate at different speeds, the present invention avoids the sheath from sticking to the inner wall of the forming cavity of the injection mold, facilitates demolding, accelerates molding, and at the same time, there is no residue of the rubber raw material in the forming cavity, improving the qualified rate of the sheath molding.
[0017] 2. By controlling the slow rotation of the middle sleeve to drive the spiral conveying blade to slowly rotate in the preheating cavity, the present invention realizes the slow conveyance of the rubber raw material in the preheating cavity, exchanges heat with the high temperature inside the injection mold, not only realizes the preliminary cooling of the sheath inside the forming cavity, but also completes the preheating of the rubber raw material, improving the subsequent heating and melting efficiency of the rubber raw material, thereby improving the injection efficiency of the sheath. Description of the Drawings
[0018] Figure 1 is a schematic structural diagram of a heat-insulating sheath injection molding system of the present invention.
[0019] Figure 2 is a cross-sectional view of the injection mold of the present invention.
[0020] Figure 3 is a cross-sectional view of the front sleeve of the present invention.
[0021] Figure 4 is of the present invention Figure 3 schematic structural diagram of the front view.
[0022] Figure 5 Cross-sectional view of the middle sleeve of the present invention.
[0023] Figure 6 Cross-sectional view of the rear sleeve of the present invention.
[0024] Figure 7 Partial cross-sectional view of the batching part of the present invention.
[0025] Figure 8 For the Figure 7 Structure schematic diagram from the official perspective.
[0026] Figure 9 Partial cross-sectional view of the material changing rack of the present invention.
[0027] Figure 10 Cross-sectional view of the annular baffle of the present invention.
[0028] Figure 11 For the Figure 2 Enlarged view of area A.
[0029] In the figure: 1, injection mold; 2, front sleeve; 3, middle sleeve; 4, rear sleeve; 5, outer tube; 6, inner tube; 7, mandrel tube; 8, forming cavity; 9, preheating cavity; 10, spiral conveying blade; 11, batching part; 12, support frame; 13, fixed ring; 14, electric heating barrel; 15, hopper; 16, material changing rack; 17, flange; 18, inner annular groove; 19, annular plate; 20, gear ring; 21, first motor; 22, second motor; 23, connecting plate; 24, rotating ring; 25, tooth ring; 26, first heat preservation barrel; 27, second heat preservation barrel; 28, avoidance opening; 29, lower discharge port; 30, outer annular groove; 31, annular baffle; 32, upper discharge hole; 33, arc-shaped tooth plate; 34, third motor; 35, connecting shaft; 36, gear; 37, filter plate; 38, annular filter net; 39, first ventilation hole; 40, second ventilation hole; 41, exhaust fan; 42, controller; 43, air vent hole; 44, lower discharge hole; 45, annular seat. Detailed implementation manners
[0030] It should be noted that, without conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.
[0031] It should be pointed out that, unless otherwise specified, all technical and scientific terms used in the present application have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.
[0032] In the present invention, unless otherwise specified, the orientations such as "upper" and "lower" generally refer to the directions shown in the drawings, or to the vertical, perpendicular or gravitational directions; similarly, for the convenience of understanding and description, "left" and "right" generally refer to the left and right shown in the drawings; "inner" and "outer" refer to the inner and outer of the contour of each component itself, but the above orientation terms are not used to limit the present invention.
[0033] Example 1. Please refer to Figures 1 - 11 , the present invention provides the following technical solutions:
[0034] A heat-insulating sheath injection molding system. Specifically, it includes a screw injection molding device and an injection mold 1 fixedly installed at the output end of the screw injection molding device; the injection mold 1 includes a front sleeve 2, a middle sleeve 3, and a rear sleeve 4 arranged coaxially; both ends of the middle sleeve 3 are rotatably matched with the front sleeve 2 and the rear sleeve 4 respectively.
[0035] The front sleeve 2 includes an outer tube 5, an inner tube 6, and a core shaft tube 7 arranged coaxially; a forming cavity 8 is formed between the core shaft tube 7 and the inner tube 6; a preheating cavity 9 is formed between the inner tube 6 and the outer tube 5; a spiral conveying blade 10 placed inside the preheating cavity 9 is fixedly installed on the outer peripheral side of the middle sleeve 3.
[0036] A batching part 11 is fixedly installed beside the screw injection molding device; the batching part 11 includes a support frame 12; a coaxial fixed ring 13 is fixedly installed at the top of the support frame 12; an electric heating barrel 14 is communicated and installed at the bottom of one fixed ring 13; a hopper 15 is communicated and installed at the top of the other fixed ring 13; a material changing frame 16 is rotatably arranged between the two fixed rings 13.
[0037] The working principle of this Example 1:
[0038] By controlling the middle sleeve 3 and the rear sleeve 4 to rotate at different speeds, it is possible to prevent the sheath from sticking to the inner wall of the forming cavity 8 in the injection mold 1, which is convenient for demolding and accelerates the molding; at the same time, there is no residue of the rubber raw material in the forming cavity 8, which improves the qualified rate of the sheath molding; by controlling the slow rotation of the middle sleeve 3 to drive the spiral conveying blade 10 to slowly rotate in the preheating cavity 9, thereby realizing the slow conveying of the rubber raw material in the preheating cavity 9 and exchanging heat with the high temperature inside the injection mold 1. This not only realizes the preliminary cooling of the sheath inside the forming cavity 8, but also completes the preheating of the rubber raw material, improves the heating and melting efficiency of the subsequent rubber raw material, and thus improves the injection molding efficiency of the sheath.
[0039] Example 2. Please refer to Figures 1 - 11, on the basis of the first embodiment, the second embodiment is improved as follows. Specifically, a flange 17 is fixed to one end of the inner tube 6; the output end of the screw injection molding device is fixedly connected to the flange 17 through fastening bolts; inner annular grooves 18 are provided on the inner peripheral side of the inner tube 6 and the inner peripheral side of the rear sleeve 4; annular plates 19 that are rotationally matched with the corresponding inner annular grooves 18 are respectively fixed to both ends of the middle sleeve 3; a sealing ring is fixed to the outer peripheral side of the annular plate 19; a sealing groove adapted to the sealing ring is provided on the inner peripheral side of the inner annular groove 18.
[0040] Toothed rings 20 are respectively fixed to the outer peripheral sides of the middle sleeve 3 and the rear sleeve 4; two first motors 21 are fixedly installed on the side of the support frame 12; first gears that are meshed with the corresponding toothed rings 20 are respectively fixed to the output ends of the two first motors 21.
[0041] The working principle of the second embodiment:
[0042] The screw injection molding device is composed of components such as a barrel, a screw, a nozzle, a hopper, a metering device, a screw drive device, an injection cylinder, and an injection seat moving cylinder. The rubber raw material is added to the electrically heated barrel 14 and heated and melted. The screw injection molding device injects a certain amount of molten material into the injection mold 1 under the action of a certain pressure and temperature to complete the injection molding of the sheath.
[0043] By fixing the flange 17 at the end of the inner tube 6 to the output end of the screw injection molding device through fastening bolts, controlling the start of the two first motors 21 to drive the corresponding first gears to rotate, thereby driving the corresponding toothed rings 20 to rotate, and controlling the rotational speed of the first motor 21 cooperating with the middle sleeve 3 to be lower than the rotational speed of the first motor 21 cooperating with the rear sleeve 4, so that the rotational speed of the middle sleeve 3 is lower than that of the rear sleeve 4. The low-speed rotation of the middle sleeve 3 is used for transition to avoid the sheath being distorted and deformed by high-speed rotation. The high-speed rotation of the rear sleeve 4 enables the sheath to basically separate from the inner wall of the rear sleeve 4, reducing the resistance when the sheath is discharged.
[0044] Embodiment Three, please refer to Figures 1 - 11 , on the basis of the second embodiment, the third embodiment is improved as follows. Specifically, a second motor 22 is fixedly installed on the side of the support frame 12; a second gear is fixed to the output end of the second motor 22; the material changing frame 16 includes a connecting plate 23; rotating rings 24 that are rotationally matched with the corresponding fixing rings 13 are respectively fixed to both ends of the connecting plate 23; a toothed ring 25 that is meshed with the second gear is fixed to the circumferential side of the connecting plate 23; a first heat preservation barrel 26 and a second heat preservation barrel 27 are respectively communicated with the circumferential sides of the two rotating rings 24; the bottoms of the first heat preservation barrel 26 and the second heat preservation barrel 27 are both open and are slidably adapted to the inner peripheral side of the corresponding fixing ring 13; avoiding openings 28 are symmetrically provided on the circumferential side of the outer tube 5 near both ends thereof.
[0045] A lower discharge port 29 is provided at the bottom of a fixed ring 13; an upper discharge port is provided at the top of another fixed ring 13; an outer annular groove 30 is provided on the outer peripheral side of the fixed ring 13; annular baffles 31 are rotatably provided in both outer annular grooves 30; an upper discharge hole 32 is provided at the top of one annular baffle 31; a lower discharge hole 44 is provided at the bottom of the other annular baffle 31.
[0046] An arc-shaped toothed plate 33 is fixed to the outer peripheral side of the annular baffle 31; a third motor 34 is fixedly installed on the side of the support frame 12; a connecting shaft 35 is fixed to the output end of the third motor 34; two groups of gears 36 are fixed to the peripheral side of the connecting shaft 35; the two gears 36 are respectively meshed and matched with the corresponding arc-shaped toothed plates 33.
[0047] A controller 42 is fixedly installed on the support frame 12; the output end of the controller 42 is electrically connected to the exhaust fan 41, the first motor 21, the second motor 22 and the third motor 34 respectively; a delivery pump is provided inside the electric heating barrel 14; the output end of the delivery pump is connected to the feed inlet of the screw injection molding device through a delivery pipe.
[0048] The working principle of the third embodiment:
[0049] In the initial state, the bottom of the first heat preservation barrel 26 is placed directly above the electric heating barrel 14, the second heat preservation barrel 27 is placed directly below the hopper 15, and the corresponding upper discharge holes 32 and lower discharge holes 44 on the two annular baffles 31 are respectively communicated with the first heat preservation barrel 26 and the second heat preservation barrel 27 (at this time, the second heat preservation barrel 27 is in an inverted state, and its bottom is placed directly below the hopper 15). By adding rubber raw materials into the hopper 15, the rubber raw materials fall into the second heat preservation barrel 27 directly below. After the rubber raw materials in the second heat preservation barrel 27 are loaded, control the third motor 34 to drive the two gears 36 to rotate synchronously, and cooperate with the corresponding arc-shaped toothed plates 33 to drive the two annular baffles 31 to rotate synchronously, so that the upper discharge holes 32 and the lower discharge holes 44 respectively rotate away from the first heat preservation barrel 26 and the second heat preservation barrel 27.
[0050] Control to start the screw injection molding device to extrude and send the molten rubber raw materials into the molding cavity 8 through the filter plate 37. At the same time, control the two first motors 21 to drive the corresponding middle sleeves 3 and rear sleeves 4 to rotate. The formed sheath slides out along the core shaft tube 7 and enters the external cold water pool for cooling.
[0051] During the slow rotation of the middle sleeve 3, the spiral conveyor blade 10 is driven to slowly rotate inside the preheating cavity 9. The rubber raw materials in the second heat preservation barrel 27 fall from its top, and the rotating spiral conveyor blade 10 slowly conveys the falling rubber raw materials into the preheating cavity 9 and falls into the first heat preservation barrel 26 for storage, realizing the preheating of the rubber raw materials.
[0052] When all the rubber raw materials inside the second heat preservation barrel 27 are collected into the first heat preservation barrel 26, control to start the second motor 22 to drive the second gear to rotate, drive the toothed ring 25 to rotate synchronously with the material changing rack 16, so that the first heat preservation barrel 26 rotates away from the electric heating barrel 14 (at this time, the first heat preservation barrel 26 is in an inverted state), and the second heat preservation barrel 27 rotates away from the hopper 15. Control to start the two first motors 21 to drive the corresponding first gears to rotate in the reverse direction, thereby driving the middle sleeve 3 to rotate in the reverse direction together with the spiral conveying blade 10. The rubber raw materials inside the first heat preservation barrel 26 fall down and are conveyed by the reversely rotating spiral conveying blade 10 through the preheating cavity 9 and finally fall back inside the second heat preservation barrel 27. Repeat the above operations to realize the reciprocating cycle preheating of the rubber raw materials, and further improve the preheating effect of the rubber raw materials.
[0053] When the preheating of the rubber raw materials is completed, control to start the third motor 34 to drive the two gears 36 to rotate synchronously in the reverse direction, so that the corresponding upper discharge holes 32 and lower discharge holes 44 on the two annular baffles 31 are respectively communicated with the first heat preservation barrel 26 and the second heat preservation barrel 27. At this time, the preheated rubber raw materials inside the first heat preservation barrel 26 fall into the electric heating barrel 14 for heating and melting. New rubber raw materials can be continuously added to the hopper 15, and the molten state is conveyed to the feeding end of the screw injection molding device through the delivery pump to complete the delivery of the molten rubber raw materials.
[0054] Embodiment 4, please refer to Figures 1 - 11 , on the basis of Embodiment 3, the following improvements are made in this Embodiment 4. Specifically, an annular filter screen 38 is fixed at the end of the outer tube 5; the core shaft tube 7, the filter plate 37, and the inner tube 6 are all provided with hollow structures inside; the inside of the core shaft tube 7 is communicated with the inside of the inner tube 6 through the filter plate 37; a plurality of first ventilation holes 39 communicated with the preheating cavity 9 are evenly opened on the outer peripheral side of the inner tube 6; a plurality of second ventilation holes 40 are evenly opened on the inner peripheral side of the core shaft tube 7; a plurality of air holes 43 are evenly opened on the spiral conveying blade 10; a filter plate 37 is fixed at the end of the inner tube 6; an annular seat 45 is fixed at the end of the core shaft tube 7; an exhaust fan 41 is fixedly installed on the annular seat 45.
[0055] The working principle of this Embodiment 4:
[0056] By controlling to start the exhaust fan 41, the external air sends the heat inside the core shaft tube 7 into the internal hollow cavity of the core shaft tube 7 through the second ventilation holes 40, and sends it into the internal hollow cavity of the inner tube 6 through the internal hollow cavity of the filter plate 37, and sends it into the preheating cavity 9 through the first ventilation holes 39 to further heat the rubber raw materials during the conveying process, and further improve the preheating effect of the rubber raw materials. The air after heat exchange is discharged through the annular filter screen 38.
[0057] Obviously, the embodiments described above are only some of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.
[0058] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.
[0059] It should be noted that the terms "first", "second", etc. in the description, claims and drawings of the present application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.
[0060] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
[0061] The above is only the preferred implementation mode of the present invention. The protection scope of the present invention is not limited to the above embodiments. Any technical solutions falling within the concept of the present invention shall belong to the protection scope of the present invention. It should be pointed out that for those of ordinary skill in the art, several improvements and refinements made without departing from the principle of the present invention should also be regarded as within the protection scope of the present invention.
Claims
1. An insulating sheath injection molding system, comprising a screw injection molding device and an injection mold (1) fixedly installed at the output end of the screw injection molding device; characterized in that: The injection mold (1) includes a front sleeve (2), a middle sleeve (3), and a rear sleeve (4) arranged coaxially; both ends of the middle sleeve (3) are rotatably matched with the front sleeve (2) and the rear sleeve (4) respectively; The front sleeve (2) includes an outer tube (5), an inner tube (6), and a mandrel tube (7) arranged coaxially; a forming cavity (8) is formed between the mandrel tube (7) and the inner tube (6); a preheating cavity (9) is formed between the inner tube (6) and the outer tube (5); a spiral conveyor blade (10) placed inside the preheating cavity (9) is fixed on the outer peripheral side of the middle sleeve (3); A batching section (11) is fixedly installed beside the screw injection device; the batching section (11) includes a support frame (12); a coaxial fixing ring (13) is fixed on the top of the support frame (12); an electric heating barrel (14) is connected and installed at the bottom of one of the fixing rings (13); a hopper (15) is connected and installed at the top of the other fixing ring (13); a material changing frame (16) is rotatably arranged between the two fixing rings (13).
2. The injection molding system for a heat insulation sheath according to claim 1, characterized in that: A flange (17) is fixed at one end of the inner tube (6); the output end of the screw injection device is fixedly connected with the flange (17) through fastening bolts; inner annular grooves (18) are formed on the inner peripheral side of the inner tube (6) and the inner peripheral side of the rear sleeve (4); annular plates (19) rotatably matched with the corresponding inner annular grooves (18) are fixed at both ends of the middle sleeve (3) respectively; a sealing ring is fixed on the outer peripheral side of the annular plate (19); a sealing groove adapted to the sealing ring is formed on the inner peripheral side of the inner annular groove (18).
3. The injection molding system for a heat insulation sheath according to claim 2, characterized in that: Toothed rings (20) are fixed on the outer peripheral sides of the middle sleeve (3) and the rear sleeve (4); two groups of first motors (21) are fixedly installed on the side of the support frame (12); first gears meshing with the corresponding toothed rings (20) are fixed at the output ends of the two first motors (21).
4. The injection molding system for a heat insulation sheath according to claim 3, wherein: A second motor (22) is fixedly installed on the side of the support frame (12); a second gear is fixed at the output end of the second motor (22); the material changing frame (16) includes a connecting plate (23); rotating rings (24) rotatably matched with the corresponding fixing rings (13) are fixed at both ends of the connecting plate (23); a toothed ring (25) meshing with the second gear is fixed on the peripheral side of the connecting plate (23); a first heat preservation barrel (26) and a second heat preservation barrel (27) are respectively connected and arranged on the peripheral sides of the two rotating rings (24); the bottoms of the first heat preservation barrel (26) and the second heat preservation barrel (27) are both open and are slidably adapted to the inner peripheral side of the corresponding fixing ring (13); avoiding openings (28) are symmetrically formed on the peripheral side of the outer tube (5) near both ends thereof.
5. An injection molding system for a heat insulation sheath according to claim 4, characterized in that: A lower discharge port (29) is formed at the bottom of the fixed ring (13); an upper discharge port is formed at the top of the fixed ring (13); an outer annular groove (30) is formed on the outer peripheral side of the fixed ring (13); annular baffles (31) are rotatably arranged in both of the outer annular grooves (30); an upper discharge hole (32) is formed at the top of one of the annular baffles (31); a lower discharge hole (44) is formed at the bottom of the other annular baffle (31).
6. The injection molding system for a heat insulation sheath according to claim 5, wherein: An arc-shaped tooth plate (33) is fixed on the outer peripheral side of the annular baffle (31); a third motor (34) is fixedly installed on the side of the support frame (12); a connecting shaft (35) is fixed at the output end of the third motor (34); two groups of gears (36) are fixed on the circumferential side of the connecting shaft (35); the two gears (36) are respectively meshed with the corresponding arc-shaped tooth plates (33).
7. The injection molding system for a heat insulation sheath according to claim 6, wherein: A filter plate (37) is fixed at the end of the inner pipe (6); an annular filter screen (38) is fixed at the end of the outer pipe (5); the core shaft pipe (7), the filter plate (37) and the inner part of the inner pipe (6) are all provided with hollow structures; the inside of the core shaft pipe (7) is communicated with the inside of the inner pipe (6) through the filter plate (37); first ventilation holes (39) communicating with the preheating cavity (9) are uniformly formed on the outer peripheral side of the inner pipe (6); a plurality of second ventilation holes (40) are uniformly formed on the inner peripheral side of the core shaft pipe (7); a plurality of air-permeable holes (43) are uniformly formed on the spiral conveying blade (10).
8. An injection molding system for a heat insulation sheath according to claim 7, characterized in that: An annular seat (45) is fixed at the end of the core shaft pipe (7); an exhaust fan (41) is fixedly installed on the annular seat (45); a controller (42) is fixedly installed on the support frame (12); the output end of the controller (42) is electrically connected to the exhaust fan (41), the first motor (21), the second motor (22) and the third motor (34) respectively; a delivery pump is arranged inside the electric heating barrel (14); the output end of the delivery pump is connected to the feed inlet of the screw injection molding device through a delivery pipe.