Extrusion head with low air gap rate

Abstract

The invention relates to a low-air-gap-rate extrusion head, and relates to the technical field of extrusion heads. The device comprises a combination part, the combination part is of a tubular structure with non-uniform inner diameters, a material passing opening is formed in one end of the combination part, a connecting opening is formed in the other end of the combination part, the opening area of the connecting opening is larger than that of the material passing opening, and the opening center of the connecting opening is flush with the opening center of the material passing opening. The diameters of the sections of the inner side walls of the combination parts evenly change from the material passing opening to the connecting opening, and the ends, close to the connecting opening, of the pair of combination parts are connected through a fast-assembling structure. When the extrusion head extrudes a spongy foaming material, in the advancing process of the foaming material, the foaming material is subjected to pressure relief firstly and then subjected to pressure reduction after passing through the middle part, so that internal gas is exhausted, and the foaming material is extruded out from the material passing opening in the other end, and the extrusion head reduces the possibility that the extruded material generates more air holes in the high-pressure process, so that the foaming material is more uniform in particle size. And the discharging quality is improved.

Description

Technical Field

[0001] The present invention relates to the field of extrusion head accessories, and particularly to an extrusion head with a low air gap rate. Background Art

[0002] The extrusion head is a key component in the extrusion molding equipment, which is used to extrude molten plastics, rubbers, metals or other materials through specific-shaped openings to form the required cross-sectional shapes. The extrusion head is widely used in the production of plastic pipes, sheets, films, profiles, cables and other products.

[0003] Currently, the general extrusion heads include a flat die head for producing flat products such as plastic films, sheets, and plates; a round die head for producing round cross-section products such as pipes, rods, and cables; a coextrusion die head for producing multi-layer composite materials, which extrudes and composites different materials simultaneously, etc.

[0004] However, in the process of processing sponge-like foamed materials, an extrusion head is often required to perform an extrusion operation on the sponge-like foamed materials. Since the sponge-like foamed material is a porous structure containing a large number of air bubbles inside, during the extrusion process of a conventional die head, due to the air in the material, more pores will be generated, resulting in a higher air gap rate of the discharged material, thus easily causing poor discharged material quality, so it needs to be improved. Summary of the Invention

[0005] In order to improve the problem of a relatively high air gap rate during the extrusion of sponge-like foamed materials by the extrusion head in the related art, the present invention provides an extrusion head with a low air gap rate.

[0006] The extrusion head with a low air gap rate provided by the present invention adopts the following technical solution: An extrusion head with a low air gap rate includes a combined part, the combined part is a tubular structure with uneven inner diameter, one end of the combined part is provided with a material passing port, the other end is provided with a connection port, the opening area of the connection port is larger than the opening area of the material passing port, the opening center of the connection port is flush with the opening center of the material passing port, the cross-sectional diameter of the inner side wall of the combined part changes uniformly from the material passing port towards the connection port, and one end of a pair of the combined parts close to the connection port is connected through a quick-installation structure.

[0007] By adopting the above technical solution, when the extrusion head in the present invention extrudes sponge-like foamed materials, since the combined part is in a horn shape and a pair of combined parts are connected to each other, during the advancing process of the foamed material, it will first release pressure, pass through the middle part and then be compressed, thereby discharging the internal gas and being extruded from the material passing port at the other end. The extrusion head in the present invention reduces the possibility of generating more pores in the extruded material during the high-pressure process and improves the discharged material quality.

[0008] Optionally, a surrounding pipe is sleeved on the side wall of the combined part. An oil injection cavity is formed between the surrounding pipe and the outer side wall of the combined part. An oil outlet is formed on the side wall of the surrounding pipe, and an oil outlet valve is sleeved on the side wall of the oil outlet.

[0009] By adopting the above technical solution, with the structure of the surrounding pipe, the operator can inject high-temperature oil into the oil injection cavity formed between the surrounding pipe and the outer side wall of the combined part through the oil outlet, so as to ensure the temperature inside the cavity and further improve the discharging quality.

[0010] Optionally, the quick installation structure includes a quick installation head and a connecting ring. The quick installation head is arranged on the side wall of one of the connecting ports away from the material passing port, and the connecting ring is arranged on the side of the connecting port of the other combined part away from the material passing port. A connecting hole for inserting the quick installation head is formed on the side wall of the connecting ring away from the material passing port. A locking piece is arranged on the side wall of the quick installation head, and a fixing structure for fixing the locking piece is arranged in the connecting hole.

[0011] By adopting the above technical solution, a pair of combined parts in the present invention are combined through the quick installation structure. On the one hand, the assembly is more convenient. On the other hand, since a pair of combined parts are generally arranged at the feeding end, the end close to the machine is more likely to be worn and aged under the vibration of the machine during production. Using the quick installation structure instead of the original integral forming structure can realize partial replacement of the extrusion head and save production costs.

[0012] Optionally, the locking piece is rotatably connected to the side wall of the quick installation head through an elastic member. A reset groove for inserting the locking piece is formed on the side wall of the quick installation head. A locking bolt is arranged on the side wall of the locking piece close to the quick installation head. A trigger groove is formed along the length direction on the end wall of the quick installation head close to the connecting hole. A trigger rod is inserted into the trigger groove, and the trigger rod is slidably connected to the trigger groove. A locking buckle is arranged at one end of the trigger rod inserted into the trigger groove, and the locking buckle is inserted into the locking bolt. When the trigger rod abuts against the bottom wall of the connecting hole and slides, the locking buckle is removed from the locking bolt.

[0013] By adopting the above technical solution, during the process of quick installation, the quick installation head on one combined part is inserted into the connecting hole. Since the trigger rod is slidably connected to the quick installation head through the trigger groove, after the trigger rod is inserted into the connecting hole along with the quick installation head, the end wall of the trigger rod abuts against the bottom wall of the connecting hole and drives the trigger rod to slide in the trigger groove, so that the locking buckle is disengaged from the locking bolt. Since the locking piece is connected to the side wall of the quick installation head through an elastic member, the locking piece rotates under the drive of the elastic member and is locked by the fixing structure, thus improving the stability of the quick installation structure.

[0014] Optionally, a stabilizing groove is formed in the inner sidewall of the triggering groove, a stabilizing magnet is inserted in the stabilizing groove, a connecting magnet is embedded in the sidewall of the triggering rod, the stabilizing magnet and the connecting magnet are magnetically attracted to each other, and when the locking buckle is removed from the locking bolt, the stabilizing magnet and the connecting magnet are adsorbed.

[0015] By adopting the above technical solution, when the triggering rod moves in the triggering groove, the locking buckle disengages from the locking bolt, thereby realizing the change in the shape of the locking piece; however, when it is necessary to disassemble the quick-release head, if the quick-release head is directly removed from the connecting hole, the inner sidewall of the connecting hole abuts against the sidewall of the locking piece, and when the locking piece is recycled, the stabilizing magnet and the connecting magnet make the locking piece not easy to slide, and then the locking bolt is not easy to reset to the reset groove, thereby affecting the reset of the locking piece.

[0016] Optionally, a locking groove is formed on the side of the connecting hole away from the quick-release head, the locking groove is communicated with the connecting hole, when the locking buckle is disengaged from the locking bolt, the locking piece rotates to be attached to the sidewall of the locking groove, the fixing structure includes a fixing ring, a fixing piece and a fixing spring, the fixing ring is embedded in the connecting ring and is rotatably connected to the connecting ring, a pair of fixing pieces are provided, the pair of fixing pieces are rotatably connected, the fixing spring is arranged between the pair of fixing pieces, the fixing spring is in a compressed state, one fixing piece abuts against the sidewall of the locking piece, and the other fixing piece abuts against the bottom wall of the connecting hole.

[0017] By adopting the above technical solution, when the locking buckle is disengaged from the locking bolt, after the locking piece rotates with the elastic member, it fits against the inner sidewall of the locking groove. At this time, if the quick-release head moves, it is difficult to stabilize the locking piece only by the elastic force of the elastic member, so that the locking piece will rotate and at the same time the quick-release head will slide along the direction of the connecting hole. By the structure of the fixing piece abutting against the locking piece and the bottom wall of the locking groove, the stability of the locking piece inserted in the connecting hole is increased.

[0018] Optionally, the sidewall of the fixing piece is an arc surface, and the opening of the pair of fixing pieces on the side close to the fixing spring is larger than the opening at the end away from the fixing spring.

[0019] By adopting the above technical solution, by adopting the structure of the fixing piece with an arc surface, the fixing piece can adjust the pressing force on the locking piece according to the opening distance. When the ends of the pair of fixing pieces close to the fixing spring abut against the sidewall of the locking piece, the stable locking of the locking piece is realized, and the assembler can rotate the fixing ring to adjust the position of the pair of fixing pieces relative to the locking piece, thereby realizing the locking and opening of the locking piece.

[0020] Optionally, a fixing colloid is provided on the side wall of the fixing piece, the fixing colloid abuts against the bottom wall of the locking piece, and the fixing colloid between the fixing piece and the locking piece is in a compressed state.

[0021] By adopting the above technical solution, the structure of the fixing colloid enables the pair of fixing pieces to be further tightened against the locking piece through the deformation of the fixing colloid during the process of abutting against the locking piece, thereby increasing the stability of the fixing piece when abutting against the locking piece.

[0022] Optionally, a limiting groove is formed on the side wall of the connecting ring close to the fixing ring, a limiting rod is provided on the side wall of the fixing ring close to the limiting groove, the limiting rod is inserted into the limiting groove, when one end of the fixing piece close to the fixing spring abuts against the side wall of the locking piece, the limiting rod abuts against the end wall of the side wall of the limiting groove, and when the other end of the fixing piece away from the fixing spring is located between the side wall of the locking piece and the inner side wall of the connecting hole, the limiting rod abuts against the other end of the limiting groove.

[0023] By adopting the above technical solution, when the assembler controls the rotation of the fixing ring, after the fixing ring rotates to abut against the side wall of the locking piece, if it is further rotated, it will cause the fixing piece to disengage from the side wall of the locking piece. Furthermore, through the structure of the limiting groove and the limiting rod, after the locking piece abuts against one end of the fixing piece close to the fixing spring, it is difficult to move further, thereby improving the stability of the fixing piece.

[0024] In summary, the present invention includes at least one of the following beneficial effects: 1. When the extrusion head in the present invention extrudes the sponge-like foaming material, since the combination part is in a horn shape and a pair of combination parts are connected to each other, when the foaming material travels, it will first release pressure, pass through the middle part and then be compressed, thereby discharging the internal gas and being extruded from the material passing port at the other end. The extrusion head in the present invention reduces the possibility of generating more pores in the extruded material during the high-pressure process and improves the discharging quality.

[0025] 2. The pair of combination parts in the present invention are combined through a quick-installation structure. On the one hand, the assembly is more convenient. On the other hand, since the pair of combination parts are generally arranged at the feeding end and the end close to the machine is more likely to be worn and aged under the vibration of the machine during production, using the quick-installation structure instead of the original integral molding structure can realize partial replacement of the extrusion head and save production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic structural diagram of an embodiment of the present invention; Figure 2 is a schematic structural diagram for embodying the connection relationship between the combination part and the surrounding pipe in an embodiment of the present invention; Figure 3is Figure 2 An enlarged schematic view of part A in Figure 4 A schematic structural view for embodying the connection relationship between the fixing structure and the locking piece in the embodiment of the present invention; Figure 5 is Figure 4 An enlarged schematic view of part B in In the figure: 1. Combined part; 11. Material passing port; 12. Connection port; 13. Enclosing pipe; 14. Oil outlet; 15. Oil injection cavity; 2. Quick installation head; 21. Connection ring; 22. Connection hole; 23. Locking piece; 24. Reset groove; 26. Trigger groove; 27. Trigger rod; 28. Trigger plate; 31. Locking buckle; 32. Locking bolt; 33. Stable groove; 331. Stable magnet; 332. Connecting magnet; 34. Locking groove; 4. Fixing structure; 41. Fixing ring; 42. Fixing piece; 43. Fixing spring; 44. Fixing colloid; 45. Limiting rod. Specific embodiments

[0027] The following will Figures 1-5 further describe the present invention in detail with reference to the attached

[0028] Embodiment 1 The embodiment of the present invention discloses a low air gap rate extrusion head. Referring to Figure 1 , a low air gap rate extrusion head includes a pair of combined parts 1, and the pair of combined parts 1 are combined and connected by means of a flange. The pair of combined parts 1 are both tubular structures with uneven inner diameters, that is, the inside of the combined part 1 is hollow and both ends are open. One end of a combined part 1 is provided with a material passing port 11, and the other end is provided with a connection port 12. The opening center of the connection port 12 and the opening center of the material passing port 11 are on the same horizontal line, and the opening center of the connection port 12 is the midpoint of the cross section of the connection port 12, and the opening center of the material passing port 11 is the midpoint of the cross section of the material passing port 11. The cross section where the connection port 12 is located and the cross section where the material passing port 11 is located are both circular. The inner hole diameter of a combined part 1 decreases from the direction of the connection port 12 towards the material passing port 11, so the pair of combined parts 1 are arranged in a cup shape.

[0029] Referring to Figure 1 and Figure 2 , a pair of combined parts 1 are fixedly welded with an enclosing pipe 13 on the outer side walls of the pair of combined parts 1. The enclosing pipe 13 is coaxially arranged with the material passing port 11 and the connection port 12 of the combined part 1. The inner side wall of the enclosing pipe 13 and the outer side wall of the combined part 1 form an oil injection cavity 15, and an oil outlet 14 is penetrated and opened on the outer side wall of the enclosing pipe 13. The oil outlet 14 is communicated with the oil injection cavity. An operator can inject hot oil into the oil injection cavity 15 through the oil outlet 14, so as to heat or keep warm the material extruded in the combined part 1, and improve the discharging quality.

[0030] Example 2 The difference between Example 2 and Example 1 is as follows: Referring to Figure 2 and Figure 3 A quick connector 2 is fixedly welded to the outer side wall of the connection port 12 of a combination part 1, and a connection ring 21 is fixedly welded to the side wall of the connection port 12 of the other combination part 1 close to the quick connector 2. A connection hole 22 is formed in the side wall of the connection ring 21. The quick connector 2 is inserted into the connection hole 22, and the quick connector 2 is slidably connected to the connection hole 22. A reset groove 24 is formed in the side wall of the connection port 12 where the quick connector 2 is inserted. A locking piece 23 is inserted into the reset groove 24. The locking piece 23 is connected to the side wall of the quick connector 2 inserted into the connection hole 22 through an elastic hinge structure, and the elastic piece is arranged in the direction towards the inside of the combination part 1. A trigger groove 26 is formed in the end wall of one end of the quick connector 2 inserted into the connection hole 22 along the length direction of the quick connector 2. A trigger rod 27 is inserted into the trigger groove 26, and the trigger rod 27 is slidably connected to the trigger groove 26. A trigger plate 28 is fixedly welded to the side wall of the connection port 12 of the combination part 1 where the connection hole 22 is located, and the trigger plate 28 is located directly below the connection hole 22. When the quick connector 2 is inserted into the connection hole 22, the end wall of the trigger rod 27 abuts against the side wall of the trigger plate 28, and as the quick connector 2 continues to be inserted, the end of the trigger rod 27 inserted into the trigger groove 26 moves in the direction away from the trigger plate 28.

[0031] Referring to Figure 2 and Figure 3 A locking buckle 31 is fixedly welded to the end wall of one end of the trigger rod 27 inserted into the trigger groove 26. A locking bolt 32 is integrally formed on the inner side wall of the locking piece 23 close to the reset groove 24. The locking buckle 31 is inserted into the locking bolt 32, so as to realize the locking of the locking piece 23. Thus, when the trigger rod 27 is inserted into the connection hole 22 along with the quick connector 2, the trigger rod 27 drives the locking buckle 31 to move out of the locking bolt 32, so that the locking piece 23 is opened under the action of the elastic hinge and fits against the side wall where the connection port 12 is located. An engagement magnet 332 is embedded in the side wall of the trigger rod 27. A stable groove 33 is formed in the inner side wall of the trigger groove 26. The stable groove 33 is communicated with the trigger groove 26. A stable magnet 331 is inserted into the stable groove 33, and the stable magnet 331 is magnetically attracted to the engagement magnet 332. When the quick connector 2 needs to be disassembled, if the quick connector 2 is directly removed from the connection hole 22, the inner side wall of the connection hole 22 abuts against the side wall of the locking piece 23 and the locking piece 23 is retracted, the stable magnet 331 and the engagement magnet 332 make the locking piece 23 not easy to slide, and thus the locking bolt 32 is not easy to reset into the reset groove 24, thereby affecting the reset of the locking piece 23.

[0032] Referring to Figure 4 andFigure 5 , a fixing structure 4 is further provided on the side wall of the combined part 1 where the connecting hole 22 is located. When the locking buckle 31 is separated from the locking bolt 32, after the locking piece 23 rotates with the elastic member, it fits against the inner side wall of the locking groove 34. At this time, if the quick-loading head 2 moves, it is difficult to stabilize the locking piece 23 only by the elastic force of the elastic member, so that the locking piece 23 will rotate, and at the same time, the quick-loading head 2 will slide along the direction of the connecting hole 22. Therefore, the fixing structure 4 is designed to fix the locking piece 23. The fixing structure 4 includes a fixing ring 41, a fixing piece 42 and a fixing spring 43. The fixing ring 41 is embedded in the outer side wall of the combined part 1 where the connecting hole 22 is located, and the fixing ring 41 is rotatably connected to the side wall of the combined part 1. There are a pair of fixing pieces 42, and one end of the pair of fixing pieces 42 is welded and fixed. The fixing piece 42 is made of rigid metal material. The opposite side walls of the pair of fixing pieces 42 are arc-shaped, that is, the vertical distance between the pair of fixing pieces 42 from the welding point to the opening gradually increases. One fixing piece 42 is welded and fixed to the side wall of the fixing ring 41, and the two fixing pieces 42 are arranged in a V shape. The fixing spring 43 is arranged between the pair of fixing pieces 42, and the fixing spring 43 is in a compressed state. A fixing colloid 44 is adhesively fixed on the side wall of the fixing piece 42. The fixing colloid 44 is in a compressed state, and the fixing piece 42 abuts against the side wall of the locking piece 23 through the fixing colloid 44. Through the structure of the fixing spring 43 and the fixing colloid 44, the fixing piece 42 presses against the locking piece 23, thereby increasing the stability of the locking piece 23 when it is locked.

[0033] Refer to Figure 4 and Figure 5 , a limiting rod 45 is welded and fixed on the side wall of the fixing ring 41 close to the connecting ring 21. A limiting groove is opened on the side wall of the connecting ring 21 close to the limiting rod 45. The limiting rod 45 is inserted into the limiting groove. When one end of the fixing piece 42 close to the fixing spring 43 abuts against the side wall of the locking piece 23, the limiting rod 45 abuts against the side wall end wall of the limiting groove. When the other end of the fixing piece 42 away from the fixing spring 43 is located between the locking piece 23 and the inner side wall of the connecting hole 22, the limiting rod 45 abuts against the other end of the limiting groove. When the assembler controls the rotation of the fixing ring 41, when the fixing ring 41 rotates until it abuts against the side wall of the locking piece 23, if it rotates further, it will cause the fixing piece 42 to disengage from the side wall of the locking piece 23. Furthermore, through the structure of the limiting groove and the limiting rod 45, after the locking piece 23 abuts against one end of the fixing piece 42 close to the fixing spring 43, it is difficult to move further, thereby improving the stability of the fixing piece 42.

[0034] The implementation principle of an extrusion head with a low air gap rate in an embodiment of the present invention is as follows: When a pair of combined parts 1 in the present invention are installed, first, the connection ports 12 of the pair of combined parts 1 are opposed to each other, and the quick-loading head 2 is inserted along the connection hole 22. When the quick-loading head 2 is inserted along the connection hole 22, the trigger rod 27 abuts against the trigger plate 28, causing the locking buckle 31 to move out of the locking bolt 32. At the same time, the stable magnet 331 and the connecting magnet 332 are adsorbed to each other. At the same time, the locking piece 23 pops out of the reset groove 24. Then, the operator rotates the fixing ring 41 so that the fixing piece 42 rotates between the locking piece 23 and the fixing ring 41, thereby fixing the locking piece 23 through the fixing ring 41. A pair of combined parts 1 in the present invention are combined through a quick-loading structure. On the one hand, the assembly is more convenient. On the other hand, since a pair of combined parts 1 are generally arranged at the feeding end, the end close to the machine is more likely to be worn and aged under the vibration of the machine during production. Using the quick-loading structure instead of the original integral molding structure can achieve partial replacement of the extrusion head, saving production costs.

[0035] The above are all the preferred embodiments of the present invention, and the protection scope of the present invention is not limited accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of the present invention should be covered within the protection scope of the present invention.

Claims

1. A low air void ratio extrusion head, characterized in that: The invention comprises a combined part (1), wherein the combined part (1) is a tubular structure with an uneven inner diameter, wherein a material passage opening (11) is provided at one end of the combined part (1), and a connecting opening (12) is provided at the other end, wherein the opening area of ​​the connecting opening (12) is larger than the opening area of ​​the material passage opening (11), the opening center of the connecting opening (12) is arranged flush with the opening center of the material passage opening (11), the cross-sectional diameter of the inner side wall of the combined part (1) changes uniformly from the material passage opening (11) toward the connecting opening (12), and a pair of ends of the combined parts (1) close to the connecting opening (12) are connected by a quick-installation structure.

2. A low air gap extrusion head according to claim 1, characterized in that: A surrounding tube (13) is sleeved on the side wall of the combined part (1), the surrounding tube (13) and the outer side wall of the combined part (1) form an oil injection cavity (15), an oil outlet (14) is opened on the side wall of the surrounding tube (13), and an oil outlet valve is sleeved on the side wall of the oil outlet (14).

3. A low air gap extrusion head according to claim 1, characterized in that: The quick-loading structure comprises a quick-loading head (2) and a connecting ring (21); the quick-loading head (2) is arranged on a side wall of one of the connecting ports (12) away from the material passage opening (11); the connecting ring (21) is arranged on a side of the connecting port (12) of the other combination part (1) away from the material passage opening (11); a connecting hole (22) for inserting the quick-loading head (2) is provided on the side wall of the connecting ring (21) away from the material passage opening (11); a locking plate (23) is provided on the side wall of the quick-loading head (2); and a fixing structure (4) for fixing the locking plate (23) is provided in the connecting hole (22).

4. A low air gap extrusion head according to claim 3, characterized in that: The locking piece (23) is rotatably connected to the side wall of the quick-loading head (2) through an elastic component; a reset groove (24) for inserting the locking piece (23) is provided on the side wall of the quick-loading head (2); a locking bolt (32) is provided on the side wall of the locking piece (23) close to the quick-loading head (2); a trigger groove (26) is provided on the end wall of the quick-loading head (2) close to the connecting hole (22) along the length direction; a trigger rod (27) is inserted into the trigger groove (26); the trigger rod (27) is slidably connected to the trigger groove (26); a locking buckle (31) is provided at one end of the trigger rod (27) inserted into the trigger groove (26); the locking buckle (31) is inserted into the locking bolt (32); when the trigger rod (27) abuts against the bottom wall of the connecting hole (22) and slides, the locking buckle (31) moves out of the locking bolt (32).

5. A low air void ratio extrusion head according to claim 4, characterized in that: A stabilizing groove (33) is provided on the inner side wall of the trigger groove (26), a stabilizing magnet (331) is inserted in the stabilizing groove (33), a connecting magnet (332) is embedded on the side wall of the trigger rod (27), the stabilizing magnet (331) and the connecting magnet (332) are magnetically attracted to each other, and when the locking buckle (31) is removed from the locking bolt (32), the stabilizing magnet (331) and the connecting magnet (332) are attracted to each other.

6. A low air void ratio extrusion head according to claim 4, characterized in that: A locking groove (34) is provided on a side of the connecting hole (22) away from the quick-release head (2). The locking groove (34) is communicated with the connecting hole (22). When the locking buckle (31) is disengaged from the locking bolt (32), the locking plate (23) rotates to fit the side wall of the locking groove (34). The fixing structure (4) comprises a fixing ring (41), a fixing plate (42) and a fixing spring (43). The fixing ring (41) is embedded in the connecting ring (21) and is rotatably connected to the connecting ring (21). A pair of fixing plates (42) are provided. The pair of fixing plates (42) are rotatably connected. The fixing spring (43) is provided between the pair of fixing plates (42). When the fixing spring (43) is in a compressed state, one of the fixing plates (42) abuts against the side wall of the locking plate (23), and the other fixing plate (42) abuts against the bottom wall of the connecting hole (22).

7. A low air void ratio extrusion head according to claim 6, characterized in that: The side wall of the fixing plate (42) is an arc surface, and the distance between a pair of fixing plates (42) close to the fixing spring (43) is greater than the distance between the ends away from the fixing spring (43).

8. The low air void ratio extrusion head according to claim 6, characterized in that: A fixing colloid (44) is arranged on the side wall of the fixing plate (42), the fixing colloid (44) abuts against the bottom wall of the locking plate (23), and the fixing colloid (44) between the fixing plate (42) and the locking plate (23) is in a compressed state.

9. The low air void ratio extrusion head according to claim 6, characterized in that: A limiting groove is provided on the side wall of the connecting ring (21) close to the fixing ring (41), and a limiting rod (45) is provided on the side wall of the fixing ring (41) close to the limiting groove. The limiting rod (45) is inserted into the limiting groove. When one end of the fixing plate (42) close to the fixing spring (43) abuts against the side wall of the locking plate (23), the limiting rod (45) abuts against the side wall end wall of the limiting groove. When one end of the fixing plate (42) away from the fixing spring (43) is located between the locking plate (23) and the inner side wall of the connecting hole (22), the limiting rod (45) abuts against the other end of the limiting groove.

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