A screw rod with self-cooling function

Abstract

The screw with self-cooling function comprises a rod body and screw ribs arranged on the rod body, the screw ribs comprise a feeding section, a compression section and a metering section, a through hole is arranged in the middle of the rod body, a screw head is detachably connected to the end of the rod body near the metering section, and the screw head seals the end opening of the through hole. The advantages of the screw are as follows: the through hole penetrates the screw, the cooling liquid can flow into the front section of the rod body, about 15-20% of the cooling blind area is eliminated, the whole screw is cooled, the cooling dead angle is avoided, the whole screw is fully cooled, the screw head is fully cooled, the overheat decomposition of the material in the screw head is effectively prevented, the end of the through hole is sealed by the screw head, the cooling liquid flowing to the end is backflowed and flows out of the through hole under pressure, the circulation of the cooling liquid is realized, the cooling liquid and the core of the screw are fully heat-exchanged, and the large amount of shearing heat generated in the compression section can be timely taken away.

Description

Technical Field

[0001] This invention relates to the field of screw manufacturing technology, and more particularly to a screw with a self-cooling function. Background Technology

[0002] Gradient screws are widely used in the extrusion processing of heat-sensitive plastics such as PVC. The material undergoes continuous shearing and compression in the gradual compression section of the screw, generating a large amount of shear heat.

[0003] Traditional solid screws cause heat to accumulate in the core and cannot dissipate, leading to the "core burning" and decomposition of PVC materials, resulting in yellow lines and black spots on the material and affecting product quality.

[0004] Existing screws with cooling chambers mostly employ a "blind hole" structure. A "blind hole" is a hole that is not open at the bottom, preventing the cooling medium from flowing to the very tip of the screw. This results in poor cooling at the head and the creation of cooling dead zones. To prevent overheating, the screw speed must be reduced, limiting production efficiency. Therefore, the structure of existing screws needs further improvement. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a screw with a self-cooling function that can fully cool the screw head, in view of the above-mentioned existing technology.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: The screw with self-cooling function includes a rod body and a screw rib provided on the rod body. The screw rib includes a feeding section, a compression section and a metering section. The screw body is characterized in that: a rod body through hole is axially provided in the middle part of the rod body, and a screw head is detachably connected to the end of the rod body near the metering section. The screw head seals the end opening of the rod body through hole.

[0007] As an improvement, a connecting thread can preferably be provided on the inner wall of the rod body through hole near the metering section, and a connecting section is provided at the end of the screw head. The outer wall of the connecting section is provided with an outer wall thread that can be screwed into the connecting thread. The connecting section is inserted into the rod body through hole and screwed into the rod body. This results in high connection efficiency, good sealing effect, and convenient screw head installation.

[0008] A further improvement is made by preferably providing an annular sealing groove on the inner wall of the through hole corresponding to both ends of the connecting thread. When the connecting section is inserted into the through hole of the rod, the sealing groove is filled with a corresponding sealing ring. This improves the sealing performance and prevents coolant leakage.

[0009] In a further improvement, the connecting section preferably includes a root column and an end column. The outer wall thread is provided on the root column, and the diameter of the end column is smaller than the diameter of the root column. A connecting recess for inserting the connecting section is provided at the end of the through hole of the rod body. The connecting thread and the sealing groove are provided on the inner wall of the connecting recess, and the root of the connecting recess is adapted to the end column. This allows for better adaptation to the through hole of the rod body and avoids eccentricity.

[0010] As a further improvement, a stepped through hole can preferably be provided on the other end of the through hole in the rod body opposite to the connecting recess, which facilitates the machining of the through hole in the rod body. This reduces the machining difficulty of the through hole in the rod body.

[0011] In a further improvement, the stepped through-hole can preferably be composed of a first through-hole, a second through-hole, a third through-hole, and a fourth through-hole in sequence, with the first and second through-holes, the second and third through-holes, and the third and fourth through-holes connected together by corresponding chamfers for a smooth transition. This further reduces the processing difficulty.

[0012] As an improvement, the through hole in the rod body can preferably include a first through hole section, a second through hole section, and a third through hole section. The diameter of the first through hole section is larger than the diameter of the third through hole section, and the diameter of the third through hole section is larger than the diameter of the second through hole section. The first through hole section corresponds to the rear section of the metering section and the compression section, and the third through hole section corresponds to the front section of the feeding section and the compression section. Sufficient cooling of the front part of the screw is achieved.

[0013] Further improvements include a preferred ratio of the length of the compression section to the length of the rod body of 0.4 to 0.5. The screw groove depth of the compression section gradually decreases along the material's forward direction. The screw groove depth at the initial position of the compression section is the same as that of the feeding section, and the screw groove depth at the end position of the compression section is the same as that of the metering section. This continuously provides shear force to promote material plasticization.

[0014] Further improvements can be made, with the screw compression ratio preferably ranging from 1.4 to 1.8. This allows for better generation of sustained shear heat to achieve material plasticization.

[0015] Further improvements include a preferred ratio of the metering section length to the rod length of 0.1 to 0.15, which better homogenizes the melt and establishes extrusion pressure.

[0016] Compared with the prior art, the advantages of this invention are as follows: the through hole in the rod body penetrates the screw, allowing coolant to flow into the front section of the rod body, eliminating approximately 15-20% of the cooling blind zone, achieving overall cooling of the screw, avoiding cooling dead zones, and thus fully cooling the entire screw; at the same time, because the screw head is fully cooled, overheating and decomposition of the material at the screw head are effectively prevented; the end of the through hole in the rod body is sealed by the screw head, causing the coolant flowing to the end to flow back out of the through hole under pressure, realizing the flow and circulation of coolant, allowing the coolant to fully exchange heat with the screw core, and timely removing a large amount of shear heat generated in the compression section, making the screw core temperature uniform and avoiding the "core burning" phenomenon; the uniform cooling and plasticizing process reduces defects such as yellow lines and black spots in PVC products, improving the appearance quality and physical properties of the product. Attached Figure Description

[0017] Figure 1 This is a perspective view of an embodiment of the present invention; Figure 2 for Figure 1 Exploded structural diagram; Figure 3 yes Figure 2 Frontal projection view after removing the screw head; Figure 4 yes Figure 3 Cross-sectional view along line AA; Figure 5 yes Figure 2 Enlarged view of section I. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0019] like Figures 1 to 5 As shown, the screw with self-cooling function in this embodiment includes a rod body 1 and a screw rib 11 provided on the rod body 1. The screw rib 11 includes a feeding section A, a compression section B, and a metering section C. A rod body through hole 10 is axially provided in the middle of the rod body 1. A screw head 2 is detachably connected to the end of the rod body near the metering section C. The screw head 2 seals the end opening 14 of the rod body through hole 1.

[0020] A connecting thread is provided on the inner wall of the rod body through hole 10 near the metering section C. A connecting section 21 is provided at the end of the screw head 2. The outer wall of the connecting section 21 is provided with an outer wall thread that can be screwed into the connecting thread. The connecting section 21 is inserted into the rod body through hole 10 and screwed into the rod body 1. An annular sealing groove 12 is provided on the inner wall of the rod body through hole 10 corresponding to both ends of the connecting thread. When the connecting section 21 is inserted into the rod body through hole 10, the sealing groove 12 is filled with a corresponding sealing ring.

[0021] The connecting section 21 includes a root column and an end column. The outer wall thread is provided on the root column. The diameter of the end column is smaller than that of the root column. A connecting recess 13 for inserting the connecting section is provided at the end of the through hole 10 of the rod body. The connecting thread and the sealing groove 12 are provided on the inner wall of the connecting recess 13. The root of the connecting recess 13 is adapted to the end column.

[0022] A stepped through hole S is provided on the other end of the rod through hole 10 opposite to the connecting recess 13 to facilitate the machining of the rod through hole. The stepped through hole S is composed of a first through hole S1, a second through hole S2, a third through hole S3, and a fourth through hole S4 in sequence. The first through hole S1 and the second through hole S2, the second through hole S2 and the third through hole S3, and the third through hole S3 and the fourth through hole S4 are connected together by corresponding chamfers for a smooth transition.

[0023] The rod body through hole 10 includes a first through hole T1, a second through hole T2, and a third through hole T3. The diameter of the first through hole T1 is larger than the diameter of the third through hole T3, and the diameter of the third through hole T3 is larger than the diameter of the second through hole T2. The first through hole T1 corresponds to the rear section of the metering section C and the compression section B, and the third through hole T3 corresponds to the front section of the feeding section A and the compression section B.

[0024] The length ratio of compression section B to rod body 1 is 0.4–0.5. The screw groove depth of compression section B gradually decreases along the material feeding direction. The screw groove depth at the initial position of compression section B is the same as that of feed section A, and the screw groove depth at the end position of compression section B is the same as that of metering section C. The screw compression ratio is 1.4–1.8. Since the screw groove depth of metering section C remains constant, and the screw groove depth of feed section A also remains constant, the screw compression ratio is the ratio of the screw groove volume at the initial position of compression section to the screw groove volume at the end position of compression section.

[0025] The ratio of the length of the measuring segment C to the length of the rod 1 is 0.1 to 0.15.

[0026] Working principle: Coolant, such as cooling water or cooling oil, flows into the inner cavity of the rod body through-hole from one end. Since the other end of the through-hole is blocked by the screw head, the pressure of the coolant gradually increases after flowing to the other end of the rod body, causing it to flow back in the opposite direction and eventually leave the through-hole, thus carrying away heat from the rod body and achieving cooling. With continuous cooling, the heated coolant flows out while new coolant flows in, allowing for continuous heat exchange between the coolant and the rod body, carrying away heat and achieving thorough cooling of the entire rod body.

Claims

1. A screw with self-cooling function, comprising a rod body (1) and a screw rib (11) disposed on the rod body (1), wherein the screw rib (11) comprises a feeding section (A), a compression section (B), and a metering section (C), characterized in that: The rod body (1) is provided with a rod body through hole (10) through the middle part of the rod body (1) in an axial direction. A screw head (2) is detachably connected to the end of the rod body near the metering section (C). The screw head (2) seals the end opening (14) of the rod body through hole (1).

2. The screw according to claim 1, characterized in that: A connecting thread is provided on the inner wall of the rod body through hole (10) near the metering section (C), and a connecting section (21) is provided at the end of the screw head (2). The outer wall of the connecting section (21) is provided with an outer wall thread that can be screwed into the connecting thread. The connecting section (21) is inserted into the rod body through hole (10) and screwed into the rod body (1).

3. The screw according to claim 2, characterized in that: An annular sealing groove (12) is provided on the inner wall of the rod through hole (10) corresponding to both ends of the connecting thread. When the connecting section (21) is inserted into the rod through hole (10), the sealing groove (12) is filled with a corresponding sealing ring.

4. The screw according to claim 3, characterized in that: The connecting section (21) includes a root column and an end column. The outer wall thread is provided on the root column. The diameter of the end column is smaller than that of the root column. A connecting recess (13) for inserting the connecting section is provided at the end of the rod through hole (10). The connecting thread and sealing groove (12) are provided on the inner wall of the connecting recess (13). The root of the connecting recess (13) is adapted to the end column.

5. The screw according to claim 4, characterized in that: A stepped through hole (S) is provided on the other end of the rod through hole (10) opposite to the connecting recess (13) to facilitate the machining of the rod through hole.

6. The screw according to claim 5, characterized in that: The stepped through hole (S) is composed of a first through hole (S1), a second through hole (S2), a third through hole (S3), and a fourth through hole (S4) in sequence. The first through hole (S1) and the second through hole (S2), the second through hole (S2) and the third through hole (S3), and the third through hole (S3) and the fourth through hole (S4) are connected together by corresponding chamfers for a smooth transition.

7. The screw according to any one of claims 1 to 6, characterized in that: The rod body through hole (10) includes a first through hole (T1), a second through hole (T2), and a third through hole (T3). The diameter of the first through hole (T1) is larger than the diameter of the third through hole (T3), and the diameter of the third through hole (T3) is larger than the diameter of the second through hole (T2). The first through hole (T1) corresponds to the rear section of the metering section (C) and the compression section (B), and the third through hole (T3) corresponds to the front section of the feeding section (A) and the compression section (B).

8. The screw according to claim 7, characterized in that: The length of the compression section (B) is 0.4 to 0.5 of the length of the rod (1). The screw groove depth of the compression section (B) gradually decreases along the material forward direction. The screw groove depth at the initial position of the compression section (B) is the same as the screw groove depth of the feeding section (A). The screw groove depth at the end position of the compression section (B) is the same as the screw groove depth of the metering section (C).

9. The screw according to claim 8, characterized in that: The screw compression ratio is 1.4 to 1.

8.

10. The screw according to claim 8, characterized in that: The ratio of the length of the measuring section (C) to the length of the rod (1) is 0.1 to 0.15.

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