Large-diameter plastic pipe extrusion die

Abstract

The invention relates to the technical field of plastic extrusion forming, in particular to a large-diameter plastic pipe extrusion die which is connected to a discharge port of an extruder and comprises a spiral body, a die body, an expansion sleeve, a mouth die and an adjusting screw, the rear end face of the spiral body is connected with the discharge port, and the spiral body is wrapped with the die body, the expansion sleeve and the mouth die from back to front. The spiral body, the die body and the expansion sleeve are connected into a whole, the mouth die is pressed and fixed to a front end opening of the expansion sleeve, a plurality of threaded through holes are evenly formed in the front end opening of the expansion sleeve along the circumference, the adjusting screws are installed in the threaded through holes, the front ends of the adjusting screws penetrate through the threaded through holes and then make contact with the mouth die, and the expansion sleeve makes contact with the rear end of the mouth die. The contact surface of the expansion sleeve and the mouth mold is a spherical surface I; according to the extrusion die, the position of the mouth die can be quickly adjusted, and the material leakage condition can be reduced.

Description

Technical Field

[0001] The invention relates to the technical field of plastic extrusion molding, in particular to a large-diameter plastic pipe extrusion die. Background Art

[0002] When producing plastic pipes, the raw materials enter the die head from the extruder, flow through the flow channel between the die and the core, enter the sizing sleeve for shaping, and then cool down to obtain the plastic pipe of the required diameter. In the production process of plastic pipes, whether the wall thickness of the plastic pipe is uniform is an important indicator affecting the quality of the pipe fittings. Therefore, during production, it is necessary to adjust the gap between the die and the core in the die head to make the pipe wall thickness uniform.

[0003] In the prior art, there are many ways to achieve uniform pipe wall thickness: 1. The invention patent with authorization announcement number CN111745934B provides a mold for producing thick-walled pipes with uniform wall thickness, including a die base, a spiral body and an outer die body connected to the die base, a shrinking core connected to the spiral body, a die core connected to the shrinking core, and a die disposed outside the die core. A flow channel is formed between the spiral body and the shrinking core and the outer die body, an extrusion channel is formed between the die and the die core, and the flow channel is connected to the extrusion channel. The die base is equipped with a driving mechanism for driving the die core to rotate. The rotation of the die core causes the inner wall of the melt in the extrusion channel to generate a circumferential motion force. Through such a reverse force, the conditions for the formation of melt accumulation caused by the destruction of melt sagging are achieved, thereby avoiding the problem of thin upper end and thick lower end of the pipe caused by melt sagging in the production of thick-walled pipes, improving the yield rate of thick-walled pipes and improving product quality. 2. Traditional equipment, by turning the adjustment bolt to change the position of the die, the pipe wall thickness is adjusted.

[0004] In the process of realizing the present invention, the inventors found that there are at least the following problems in the prior art: the method of making the pipe wall thickness uniform by rotating the mold core has a high degree of equipment structure complexity and high equipment cost; the method of adjusting the position of the die has a low equipment manufacturing cost, but leakage is likely to occur between the die and the expansion sleeve, wasting raw materials, and when adjusting, each adjusting bolt needs to be readjusted to a new tightness, which is inconvenient to operate. Summary of the invention

[0005] Aiming at the deficiencies of the prior art, the present invention develops a large-diameter plastic pipe extrusion die, which can quickly adjust the position of the die and reduce material leakage.

[0006] The technical solution to the technical problem solved by the present invention is as follows: an embodiment of the present invention provides a large-diameter plastic pipe extrusion die, which is connected to the discharge port of an extruder, and includes a spiral body, a die body, an expansion sleeve, a die, and an adjusting screw. The rear end face of the spiral body is connected to the discharge port, and the die body, the expansion sleeve, and the die are wrapped around the outside of the spiral body from back to front. The spiral body, the die body, and the expansion sleeve are connected as a whole. The die is pressed and fixed at the front end opening of the expansion sleeve. A plurality of threaded through holes are evenly arranged along the circumference of the front end opening of the expansion sleeve. The adjusting screw is installed in the threaded through hole. The front end of the adjusting screw contacts the die after passing through the threaded through hole. The expansion sleeve contacts the rear end of the die, and the contact surface between the expansion sleeve and the die is a spherical surface.

[0007] As an optimization, the extrusion die also includes a pressure plate, which is fixed to the front end face of the expansion sleeve by a tightening screw. The die is arranged between the pressure plate and the expansion sleeve. The pressure plate fixes the die on the expansion sleeve. The pressure plate is block-shaped, and a spherical protrusion is arranged on the surface opposite to the die.

[0008] As an optimization, the adjusting screw contacts the side or end face of the die. The center of the spherical surface 1 in the large-diameter extrusion die is located at the front end of the front end face of the expansion sleeve, and the die can be rotated by applying force to the side or end face of the die.

[0009] As an optimization, three pressing plates and three adjusting screws are evenly arranged along the circumference of the central axis of the expansion sleeve, and the pressing plates and the adjusting screws are spaced apart.

[0010] As an optimization, the extrusion die is arranged horizontally, and an adjusting screw is arranged on the top of the expansion sleeve.

[0011] As an optimization, the extrusion die also includes a clamping plate, which is in a circular ring shape and connected to the die. The clamping plate contacts the front end of the die, and the contact surface between the die and the clamping plate is spherical surface 2, and spherical surface 1 is concentric and has the same diameter as spherical surface 2.

[0012] As an optimization, the extrusion die further includes a tie rod and a pin, which are evenly distributed along the center of the clamping plate and the expansion sleeve, and are arranged at intervals, and the tie rod and the pin connect the clamping plate and the expansion sleeve. The tie rod is a long bolt, and the clamping plate and the expansion sleeve are provided with connection ports and pin holes corresponding to the tie rod and the pin.

[0013] As an optimization, the extrusion die also includes a support plate, an adjustment rod, and a cap seat. The cap seat is in the shape of an open spherical cover and is fixed to the front end side of the die. The support plate is arranged at the front end of the clamping plate. A penetrating threaded hole is arranged on the support plate. The adjustment rod is a screw rod. The adjustment rod passes through the threaded hole on the support plate. The lower end of the adjustment rod passes through the cap seat and is connected to a ball. The support plate, the adjustment rod, and the cap seat are evenly arranged in at least three groups along the circumference of the center line of the die.

[0014] As an optimization, the discharge port is arranged vertically downward, and the extrusion die is arranged vertically downward.

[0015] The effects provided in the summary of the invention are only the effects of the embodiments, rather than all the effects of the present invention. The above technical solution has the following advantages or beneficial effects:

[0016] 1. By rotating the adjusting screw, the die can be rotated along the center of the spherical surface to adjust the position of the die, thereby adjusting the shape of the outlet of the flow channel at the front end of the spiral body and adjusting the thickness of the plastic pipe. By setting the contact surface between the expansion sleeve and the die as a spherical surface, the sealing between the expansion sleeve and the die is improved, which can reduce leakage.

[0017] 2. By arranging a spherical protrusion on the surface of the pressing plate opposite to the die, the spherical protrusion of the pressing plate is in point contact with the die, so that the rotating die can be pressed and fixed.

[0018] 3. By setting three pressure plates and adjusting screws at intervals, the number of clamping screws and adjusting screws is reduced to the greatest extent, and the adjustment speed of the die position is improved.

[0019] 4. By setting a clamp, and the clamp presses and fixes the die on the expansion sleeve, the contact surface of the die, the clamp and the expansion sleeve is the same spherical surface, and the pressing force applied by the fixed die does not need to be too large to ensure the sealing. When rotating the adjusting screw, there is no need to loosen the connection between the clamp and the expansion sleeve, and the die position can be adjusted quickly.

[0020] 5. By setting at least three groups of support plates, adjustment rods and cap seats, the front end of the die can be stretched and squeezed, the shape of the die can be changed, the adjustment method is increased, and the thickness of the plastic pipe can be adjusted more flexibly.

[0021] 6. By setting the discharge port and the extrusion die vertically downward, the raw materials in the radial direction of the plastic pipe are evenly stressed, avoiding the influence of gravity and further improving the uniformity of the thickness of the plastic pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a left view of the first embodiment of the present invention.

[0023] Figure 2 This is a general structural diagram of the first embodiment of the present invention.

[0024] Figure 3 It is a left view of the second embodiment of the present invention.

[0025] Figure 4 This is a general structural diagram of the second embodiment of the present invention.

[0026] Among them: spiral body 1, mold body 2, expansion sleeve 3, die 4, adjustment screw 5, pressure plate 6, clamping plate 7, support plate 8, adjustment rod 9, cap seat 10, pull rod 11, pin 12, discharge port 20, spherical surface 1 41, spherical surface 2 42. DETAILED DESCRIPTION

[0027] In order to clearly illustrate the technical features of the present invention, the present invention is described in detail below through specific implementation methods and in conjunction with the accompanying drawings.

[0028] Figure 1 , Figure 2 As an embodiment of the present invention, Figure 2 As shown, a large-diameter plastic pipe extrusion die is connected to the discharge port 20 of the extruder, including a spiral body 1, a die body 2, an expansion sleeve 3, a die 4, an adjusting screw 5, and a pressing plate 6. The rear end face of the spiral body 1 is connected to the discharge port 20, the die body 2, the expansion sleeve 3, and the die 4 are wrapped on the outside of the spiral body 1 from back to front, the spiral body 1, the die body 2, and the expansion sleeve 3 are connected as a whole, the die 4 is pressed and fixed at the front end opening of the expansion sleeve 3, and the front end opening of the expansion sleeve 3 is evenly arranged along the circumference. The adjusting screw 5 is installed in the threaded through hole, and the front end of the adjusting screw 5 contacts the die 4 after passing through the threaded through hole, the expansion sleeve 3 contacts the rear end of the die 4, and the contact surface between the expansion sleeve 3 and the die 4 is a spherical surface 41. The pressing plate 6 is fixed to the front end face of the expansion sleeve 3 by a clamping screw, and the die 4 is arranged between the pressing plate 6 and the expansion sleeve 3. The pressing plate 6 fixes the die 4 to the expansion sleeve 3. The pressing plate 6 is block-shaped, and a spherical protrusion is arranged on the surface of the pressing plate 6 opposite to the die 4. By arranging the spherical protrusion on the surface of the pressing plate 6 opposite to the die 4, the spherical protrusion of the pressing plate 6 and the die 4 are in point contact, and the rotating die 4 can be clamped and fixed. The adjusting screw 5 is in contact with the side of the die 4. The center of the spherical surface 41 in the large-diameter extrusion die is located at the front end of the front end face of the expansion sleeve 3, and the die 4 can be rotated by applying a force to the side or end face of the die 4.

[0029] like Figure 1 As shown, three pressing plates 6 and adjusting screws 5 are respectively arranged uniformly along the central axis of the expansion sleeve 3, and the pressing plates 6 and adjusting screws 5 are spaced apart. By arranging three pressing plates 6 and adjusting screws 5 at intervals, the number of clamping screws and adjusting screws 5 is reduced to a great extent, and the adjustment speed of the position of the die 4 is improved. The extrusion die is arranged horizontally, and one adjusting screw 5 is arranged at the top of the expansion sleeve 3. By arranging one adjusting screw 5 at the top of the expansion sleeve 3, when the extrusion die is arranged horizontally, the thickness of the upper end of the plastic tube can be reduced by loosening the adjusting screws 5 on both sides of the lower end of the expansion sleeve 3 and tightening the adjusting screws 5 on the top of the expansion sleeve 3; conversely, the thickness of the upper end of the plastic tube can be increased by loosening the adjusting screws 5 on the top of the expansion sleeve 3 and tightening the adjusting screws 5 on both sides of the lower end of the expansion sleeve 3.

[0030] Figure 3 , Figure 4 For the second embodiment of the present invention, Figure 4 As shown, a large-diameter plastic pipe extrusion die is connected to the discharge port 20 of the extruder, including a spiral body 1, a die body 2, an expansion sleeve 3, a die 4, an adjusting screw 5, and a clamp 7. The rear end face of the spiral body 1 is connected to the discharge port 20, the die body 2, the expansion sleeve 3, and the die 4 are wrapped on the outside of the spiral body 1 from back to front, the spiral body 1, the die body 2, and the expansion sleeve 3 are connected as a whole, the die 4 is pressed and fixed at the front end opening of the expansion sleeve 3, and the front end opening of the expansion sleeve 3 is evenly arranged along the circumference. The adjusting screw 5 is installed in the threaded through hole, and the front end of the adjusting screw 5 contacts the die 4 after passing through the threaded through hole, the expansion sleeve 3 contacts the rear end of the die 4, and the contact surface between the expansion sleeve 3 and the die 4 is a spherical surface 41. The clamping plate 7 is in a circular ring shape, and the clamping plate 7 is connected to the die 4. The clamping plate 7 contacts the front end of the die 4. The contact surface between the die 4 and the clamping plate 7 is a spherical surface 2 42, and the spherical surface 1 41 is concentric with the spherical surface 2 42. By setting the clamping plate 7, and clamping the die 4 to be pressed and fixed on the expansion sleeve 3, the contact surface between the die 4 and the clamping plate 7 and the expansion sleeve 3 is the same spherical surface, and the pressing force applied by the fixed die 4 does not need to be too large to ensure the sealing. When rotating the adjusting screw 5, there is no need to loosen the connection between the clamping plate 7 and the expansion sleeve 3, and the position of the die 4 can be quickly adjusted. The extrusion die also includes a tie rod 11 and a pin 12. The tie rod 11 and the pin 12 are evenly distributed along the center of the clamping plate 7 and the expansion sleeve 3. The tie rod 11 and the pin 12 are arranged at intervals, and the tie rod 11 and the pin 12 connect the clamping plate 7 and the expansion sleeve 3. The pull rod 11 is a long bolt, and the clamping plate 7 and the expansion sleeve 3 are provided with a connection port and a pin hole corresponding to the pull rod 11 and the pin shaft 12. The extrusion die also includes a support plate 8, an adjustment rod 9, and a cap seat 10. The cap seat 10 is an open spherical cover shape, and the cap seat 10 is fixed to the front end side of the die 4. The support plate 8 is arranged at the front end of the clamping plate 7, and a threaded hole is arranged on the support plate 8. The adjustment rod 9 is a screw rod, and the adjustment rod 9 passes through the threaded hole on the support plate 8. The lower end of the adjustment rod 9 passes through the cap seat 10 and is connected to a ball. The support plate 8, the adjustment rod 9, and the cap seat 10 are evenly arranged in four groups along the center line circumference of the die 4. By setting at least three groups of support plates 8, adjustment rods 9, and cap seats 10, the front end of the die 4 can be stretched and squeezed, the shape of the die 4 can be changed, the adjustment method is increased, and the thickness of the plastic pipe can be adjusted more flexibly.

[0031] The plastic raw material flows out from the discharge port 20 of the extruder, and enters the flow channel of the rear end face of the spiral body 1, the spiral flow channel between the die body 2 and the spiral body 1, the flow channel between the expansion sleeve 3 and the spiral body 1, and the flow channel between the die 4 and the spiral body 1 in turn, and finally flows out from the front end of the spiral body 1, and forms a plastic tube after cooling. By rotating the adjustment screw 5, the die 4 can be rotated along the center of the sphere 41 to adjust the position of the die 4, thereby adjusting the shape of the outlet of the flow channel at the front end of the spiral body 1 and adjusting the thickness of the plastic tube. By setting the contact surface between the expansion sleeve 3 and the die 4 as a spherical surface, the sealing between the expansion sleeve 3 and the die 4 is improved, and leakage can be reduced.

[0032] When in use, the discharge port 20 and the extrusion die can be arranged vertically downward. By arranging the discharge port 20 and the extrusion die vertically downward, the raw materials in the radial direction of the plastic pipe are uniformly stressed, avoiding the influence of gravity, and further improving the uniformity of the thickness of the plastic pipe.

[0033] Although the above describes the specific implementation mode of the invention in conjunction with the drawings, it is not intended to limit the scope of protection of the invention. Based on the technical solution of the present invention, various modifications or variations that can be made by those skilled in the art without creative work are still within the scope of protection of the present invention.

Claims

1. A large-diameter plastic pipe extrusion die, connected to a discharge port (20) of an extruder, comprising a spiral body (1), a die body (2), an expansion sleeve (3), a die (4), and an adjusting screw (5), wherein the rear end face of the spiral body (1) is connected to the discharge port (20), the die body (2), the expansion sleeve (3), and the die (4) are wrapped around the outside of the spiral body (1) from back to front, the spiral body (1), the die body (2), and the expansion sleeve (3) are connected as a whole, the die (4) is pressed and fixed at the front end opening of the expansion sleeve (3), the front end opening of the expansion sleeve (3) is evenly provided with a plurality of threaded through holes along the circumference, the adjusting screw (5) is installed in the threaded through hole, and the front end of the adjusting screw (5) contacts the die (4) after passing through the threaded through hole, wherein the adjusting screw (5) is characterized in that: The expansion sleeve (3) contacts the rear end of the die (4), and the contact surface between the expansion sleeve (3) and the die (4) is a spherical surface (41).

2. A large-diameter plastic pipe extrusion die according to claim 1, characterized in that: The extrusion die also includes a pressing plate (6), which is fixed to the front end surface of the expansion sleeve (3) by means of a clamping screw. The die (4) is arranged between the pressing plate (6) and the expansion sleeve (3). The pressing plate (6) fixes the die (4) on the expansion sleeve (3). The pressing plate (6) is block-shaped, and a spherical protrusion is arranged on the surface of the pressing plate (6) opposite to the die (4).

3. A large-diameter plastic pipe extrusion die according to claim 1, characterized in that: The adjusting screw (5) contacts the side surface or end surface of the die (4).

4. A large-diameter plastic pipe extrusion die according to claim 2, characterized in that: The pressure plates (6) and the adjusting screws (5) are respectively arranged in three evenly spaced circles along the central axis of the expansion sleeve (3), and the pressure plates (6) and the adjusting screws (5) are spaced apart from each other.

5. A large-diameter plastic pipe extrusion die according to claim 4, characterized in that: The extrusion die is arranged horizontally, and an adjusting screw (5) is arranged on the top of the expansion sleeve (3).

6. A large-diameter plastic pipe extrusion die according to claim 1, characterized in that: The extrusion die also includes a clamping plate (7) which is in the shape of a circular ring and is connected to the die (4). The clamping plate (7) contacts the front end of the die (4). The contact surface between the die (4) and the clamping plate (7) is a second spherical surface (42). The first spherical surface (41) and the second spherical surface (42) are concentric and have the same diameter.

7. A large-diameter plastic pipe extrusion die according to claim 6, characterized in that: The extrusion die also includes a tie rod (11) and a pin (12). The tie rod (11) and the pin (12) are evenly distributed along the center of the clamping plate (7) and the expansion sleeve (3). The tie rod (11) and the pin (12) are arranged at intervals. The tie rod (11) and the pin (12) connect the clamping plate (7) and the expansion sleeve (3).

8. A large-diameter plastic pipe extrusion die according to claim 6, characterized in that: The extrusion die also includes a support plate (8), an adjustment rod (9), and a cap seat (10). The cap seat (10) is in the shape of an open spherical cover. The cap seat (10) is fixed to the front end side of the die (4). The support plate (8) is arranged at the front end of the clamping plate (7). A threaded hole is arranged on the support plate (8). The adjustment rod (9) is a screw rod. The adjustment rod (9) passes through the threaded hole on the support plate (8). The lower end of the adjustment rod (9) passes through the cap seat (10) and is connected to a ball. The support plate (8), the adjustment rod (9), and the cap seat (10) are evenly arranged in at least three groups along the circumference of the center line of the die (4).

9. A large-diameter plastic pipe extrusion die according to claim 1, characterized in that: The discharge port (20) is arranged vertically downward, and the extrusion die is arranged vertically downward.

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