Spiral pipe extrusion die for PVC (polyvinyl chloride) drainage pipe
By using bearings and positioning part design in PVC drain pipe spiral pipe extrusion mold, the problem of uneven wall thickness caused by the spiral core swing is solved, and the stable production and quality control of PVC drain pipes are achieved.
Patent Information
- Application Number
- CN202422132238.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-30
- Publication Date
- 2025-07-25
- Estimated Expiration
- 2034-08-30
AI Technical Summary
In the prior art, the inlayed copper sleeve on the spiral die core is worn, causing the spiral die core to sway, resulting in the problem of uneven wall thickness of the PVC drain pipe.
The PVC drain pipe spiral tube extrusion die design includes an outer die sleeve, die core, rotary shaft and drive section. By providing the first and second bearings on the rotary shaft, friction is reduced, and the slant is avoided through the design of the positioning section, combining the flow guide section and anti-wear gasket to improve production stability.
It effectively avoids the slanting of the spiral die core during rotation, ensures the uniformity of the wall thickness of the PVC drainage pipe, and improves the stability and quality of production.
Smart Images
Figure CN223147706U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of PVC drain pipe molds, and more specifically, to a spiral pipe extrusion mold for PVC drain pipes. Background Art
[0002] The PVC spiral pipe is a PVC drain pipe with spiral ribs on the inner wall. When in use, the ribs on the inner wall of the PVC spiral pipe can guide the water flow in the pipe, making the water flow in the drain pipe advance in a swirling manner until it is discharged from the PVC spiral pipe. The spiral water flow can increase the impact force on the inner side wall of the drain pipe, reduce the adhesion of dirt in the water flow to the inner side wall of the drain pipe, and reduce the probability of the drain pipe being blocked.
[0003] The PVC spiral pipe with spiral ribs on the inner wall needs to be produced using a spiral pipe extrusion mold. In order to process the spiral ribs inside the pipe, the spiral mold core needs to be rotated during the extrusion of the PVC spiral pipe to form spiral ribs on the inner side wall of the pipe. When the spiral mold core rotates, it will rub against the mold core sleeve, resulting in wear of the spiral mold core. In the prior art, in order to avoid wear of the spiral mold core, a copper sleeve is inlaid on the spiral mold core, and the copper sleeve is used to prevent the spiral mold core from directly contacting the mold core sleeve, thereby avoiding wear of the spiral mold core. However, when the inlaid copper sleeve on the spiral mold core is worn, the spiral mold core will deflect during rotation, resulting in uneven wall thickness of the produced PVC drain pipe and affecting the quality of the PVC drain pipe. Summary of the Utility Model
[0004] The utility model aims to overcome the problem in the above-mentioned prior art that when the inlaid copper sleeve on the spiral mold core is worn, the spiral mold core will deflect, resulting in uneven wall thickness of the PVC drain pipe. The utility model provides a spiral pipe extrusion mold for PVC drain pipes, and this solution can prevent the spiral mold core in the mold from deflecting during rotation, thereby avoiding uneven wall thickness of the produced PVC drain pipe.
[0005] To solve the above technical problems, the technical solution adopted by the utility model is: a spiral pipe extrusion mold for PVC drain pipes, including an outer mold sleeve and a mold core, a rotating shaft, and a driving part located in the inner cavity of the outer mold sleeve. A flow channel is formed between the outer mold sleeve and the mold core. The mold core includes a spiral mold core and a mold core sleeve. One end of the spiral mold core is provided with a groove for forming pipe ribs, and the other end is provided with a positioning part inserted into the inner cavity of the mold core sleeve. One end of the rotating shaft passes through the mold core sleeve and is fixedly connected to the spiral mold core, and the other end is connected to the driving end of the driving part. A first bearing is sleeved on the positioning part, and the outer ring of the first bearing abuts against the inner cavity of the mold core sleeve. One end of the rotating shaft close to the driving part is sleeved with a second bearing, and the outer ring of the second bearing abuts against the inner side wall of the mold core.
[0006] After the raw materials enter the mold, they move forward along the runner between the outer mold sleeve and the mold core, flow through the mold core sleeve, and are extruded from the runner at the spiral mold core. The driving part drives the rotating shaft to rotate, the rotating shaft drives the spiral mold core to rotate, and when the spiral mold core rotates, the grooves on the spiral mold core rotate synchronously with the spiral mold core. The raw materials pass through the grooves on the spiral mold core before being extruded, and the rotating grooves cause spiral protrusions to be generated in the inner cavity of the pipe extruded from the spiral mold core. At the same time, the rotation of the rotating shaft will drive the inner ring of the second bearing to rotate, and the second bearing can reduce the friction between the rotating shaft and the mold core during rotation; the rotation of the spiral mold core will drive the inner ring of the first bearing on the positioning part to rotate, and the first bearing can reduce the friction between the spiral mold core and the mold core sleeve during rotation.
[0007] In the mold of this solution, the setting of the first bearing and the second bearing can make the rotating shaft have less friction when driving the spiral mold core to rotate. Under the action of the two bearings, it can avoid the yaw of the rotating shaft and the spiral mold core, and further avoid the problem of uneven wall thickness of the produced PVC spiral water pipe. At the same time, the positioning part extends into the inner cavity of the mold core sleeve. When the spiral mold core deflects, it will interfere with the inner cavity of the mold core sleeve, which can further restrict the rotation of the spiral mold core and avoid the yaw of the spiral mold core.
[0008] Preferably, the axis of the groove is spirally wound around the outer surface of the spiral mold core. One end of the groove close to the mold core sleeve is provided with a diversion section. There are several grooves, and several grooves are arranged at equal circumferential intervals with the axis of the spiral mold core as the rotation axis. One end of the diversion section close to the mold core sleeve is a sharp angle, the other end is connected to the groove, and the bottom surface of the diversion section is conical. The axis of the groove is spirally wound around the outer surface of the spiral mold core. When the molten raw materials advance along the groove, the spiral groove can make the spiral axis density of the protrusions on the inner surface of the extruded pipe higher as the spiral mold core rotates. The setting of the diversion section can make it more convenient for the molten raw materials to flow into the groove.
[0009] Preferably, the mold core further includes a fixed mold core and a material distribution head. The spiral mold core, the mold core sleeve, the fixed mold core and the material distribution head are connected in sequence. The fixed mold core and the material distribution head are connected by a support plate. The driving part is located in the inner cavity of the support plate. The rotating shaft passes through the fixed mold core, the mold core sleeve and the spiral mold core in sequence. There is a square section on the rotating shaft. The square section passes through the spiral mold core and fits with the inner side wall of the spiral mold core. There is also a locking bolt at one end of the rotating shaft away from the driving part. The locking bolt is threadedly connected to the rotating shaft, and the end face of the locking bolt abuts against the end face of the spiral mold core. The rotating shaft drives the spiral mold core to rotate through the square section, and the cross section of the square section can also be replaced with any polygon. The nut of the locking bolt abuts against the end face of the spiral mold core, clamping the spiral mold core between the nut of the locking bolt and the mold core sleeve.
[0010] Preferably, a transmission gear is sleeved on one end of the rotating shaft connected to the driving part. The transmission gear is fixedly connected to the rotating shaft, and the driving end of the driving part meshes with the transmission gear. The driving part drives the rotating shaft to rotate through the transmission gear, without the need for the driving part and the rotating shaft to be arranged on the same axis, which can shorten the length of the mold.
[0011] Preferably, it further includes a third bearing. The third bearing is sleeved on the rotating shaft, the outer ring of the third bearing abuts against the inner side wall of the core sleeve, a limiting protrusion is provided on the rotating shaft, a stepped surface is provided in the inner cavity of the core sleeve, and the two end faces of the third bearing respectively abut against the limiting protrusion and the stepped surface. The third bearing is sleeved on the rotating shaft, and the third bearing is located between the first bearing and the second bearing, which can further prevent the rotating shaft from deflecting during rotation.
[0012] Preferably, it further includes an anti-wear gasket. The anti-wear gasket is sleeved on the positioning part, and the two ends of the anti-wear gasket respectively abut against the end face of the core sleeve and the end face of the spiral core. The first bearing is located at one end of the positioning part away from the anti-wear gasket. The anti-wear gasket is sleeved on the positioning part, and the spiral core contacts the core sleeve through the anti-wear gasket. The anti-wear gasket can prevent contact between the spiral core and the core sleeve, thereby avoiding wear between the spiral core and the core sleeve when the spiral core rotates. When the spiral core deflects, the end of the spiral core closer to the driving part wears the most. The first bearing is located at one end of the positioning part away from the anti-wear gasket, so that the first bearing is located at the position on the spiral core where wear is most likely to occur, further reducing the probability of the spiral core deflecting.
[0013] Preferably, the outer mold sleeve includes an outer mold cavity plate and a discharge outer mold. The discharge outer mold is detachably connected to the outer mold cavity plate. The discharge outer mold includes a discharge plate, a discharge port and a pressing plate. A positioning groove is provided on the discharge plate. The discharge port is located in the positioning groove and fits against the side wall of the positioning groove. The outer side wall of the discharge port is a stepped surface. The pressing plate is sleeved on the stepped surface and abuts against the stepped surface. The pressing plate is detachably connected to the discharge plate.
[0014] Preferably, the runner includes a first contraction section and a second contraction section. The first contraction section is located between the core and the outer mold cavity plate. In the plane where the axis of the core is located, the included angle between the outer side wall of the cross-section of the first contraction section and the horizontal plane is 18° - 30°; the included angle between the inner side wall of the first contraction section and the horizontal plane is 10° - 15°; the second contraction section is located between the core and the discharge plate. In the plane where the axis of the core is located, the included angle between the outer side wall of the second contraction section and the horizontal plane is 6° - 12°, and the included angle between the inner side wall of the second contraction section and the horizontal plane is 170° - 175°.
[0015] Compared with the prior art, the beneficial effects of the present utility model are as follows: In this solution, the setting of the first bearing and the second bearing enables the rotating shaft to have smaller friction when driving the spiral die core to rotate. Under the action of the two bearings, the rotating shaft and the spiral die core can be prevented from yawing, thereby avoiding the problem of uneven wall thickness of the produced PVC spiral water pipe. At the same time, the positioning portion extends into the inner cavity of the die core sleeve. When the spiral die core deflects, it will interfere with the inner cavity of the die core sleeve, which can further restrict the rotation of the spiral die core and avoid the yawing of the spiral die core. Brief Description of the Drawings
[0016] Figure 1 is a schematic internal structure diagram of a spiral pipe extrusion die for a PVC drain pipe of the present utility model;
[0017] Figure 2 is a schematic internal structure diagram of the die core of a spiral pipe extrusion die for a PVC drain pipe of the present utility model;
[0018] Figure 3 is a schematic structural diagram of the spiral die core of a spiral pipe extrusion die for a PVC drain pipe of the present utility model;
[0019] Figure 4 is a schematic internal structure diagram of Embodiment 3 of a spiral pipe extrusion die for a PVC drain pipe of the present utility model. Detailed Embodiment
[0020] The drawings are only for illustrative purposes and should not be construed as a limitation of this patent; for better illustration of this embodiment, some components in the drawings will be omitted, enlarged or reduced, which do not represent the dimensions of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted. The positional relationships described in the drawings are only for illustrative purposes and should not be construed as a limitation of this patent.
[0021] In the drawings of the embodiments of the present utility model, the same or similar reference numerals correspond to the same or similar components; in the description of the present utility model, it should be understood that if there are terms such as "upper", "lower", "left", "right", "long", "short", etc. indicating the orientation or positional relationship, they are based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only for illustrative purposes and should not be construed as a limitation of this patent. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.
[0022] The technical solutions of the present utility model will be further specifically described below through specific embodiments and in conjunction with the drawings:
[0023] Example 1
[0024] An embodiment of a spiral pipe extrusion die for a PVC drain pipe, as Figure 1 and Figure 3 shown, includes an outer die sleeve 1 and a die core 2, a rotating shaft 3 and a driving part located in the inner cavity of the outer die sleeve 1. A flow channel 4 is formed between the outer die sleeve 1 and the die core 2. The die core 2 includes a spiral die core 201 and a die core sleeve 202. One end of the spiral die core 201 is provided with a groove 5 for forming a convex rib of the pipe, and the other end is provided with a positioning part 6 inserted into the inner cavity of the die core sleeve 202. One end of the rotating shaft 3 passes through the die core sleeve 202 and is fixedly connected to the spiral die core 201, and the other end is connected to the driving end of the driving part. A first bearing 7 is sleeved on the positioning part 6, and the outer ring of the first bearing 7 abuts against the inner cavity of the die core sleeve 202. A second bearing 8 is sleeved on one end of the rotating shaft 3 close to the driving part, and the outer ring of the second bearing 8 abuts against the inner side wall of the die core 2.
[0025] The working principle or process of this embodiment: After the raw material enters the die, it moves forward along the flow channel 4 between the outer die sleeve 1 and the die core 2, and is extruded from the flow channel 4 at the spiral die core 201 after flowing through the die core sleeve 202. The driving part drives the rotating shaft 3 to rotate, the rotating shaft 3 drives the spiral die core 201 to rotate, and when the spiral die core 201 rotates, the groove 5 on the spiral die core 201 rotates synchronously with the spiral die core 201. The raw material passes through the groove 5 on the spiral die core 201 before being extruded, and the rotating groove 5 causes a spiral protrusion to be generated in the inner cavity of the pipe extruded from the spiral die core 201. At the same time, the rotation of the rotating shaft 3 will drive the inner ring of the second bearing 8 to rotate, and the second bearing 8 can reduce the friction between the rotating shaft 3 and the die core 2 when the rotating shaft 3 rotates; the rotation of the spiral die core 201 will drive the inner ring of the first bearing 7 on the positioning part 6 to rotate, and the first bearing 7 can reduce the friction between the spiral die core 201 and the die core sleeve 202 when the spiral die core 201 rotates.
[0026] The beneficial effects of this embodiment: In this solution, the setting of the first bearing 7 and the second bearing 8 can make the rotating shaft 3 have less friction when driving the spiral die core 201 to rotate. Under the action of the two bearings, the rotation shaft 3 and the spiral die core 201 can be prevented from yawing, thereby avoiding the problem of uneven wall thickness of the produced PVC spiral water pipe. At the same time, the positioning part 6 extends into the inner cavity of the die core sleeve 202. When the spiral die core 201 deflects, it will interfere with the inner cavity of the die core sleeve 202, which can further restrict the rotation of the spiral die core 201 and avoid the yaw of the spiral die core 201.
[0027] Example 2
[0028] An embodiment 2 of a spiral pipe extrusion die for a PVC drain pipe, on the basis of embodiment 1, as Figures 1 - 3 shown, further defines the structures of the die core 2 and the rotating part.
[0029] Specifically, the axis of the groove 5 is spirally wound around the outer surface of the spiral core 201. A diversion section 501 is provided at one end of the groove 5 close to the core sleeve 202. There are several grooves 5, and the several grooves 5 are arranged at equal circumferential intervals around the axis of the spiral core 201 as the rotation axis 3. One end of the diversion section 501 close to the core sleeve 202 is a sharp angle, the other end is communicated with the groove 5, and the bottom surface of the diversion section 501 is conical.
[0030] Specifically, the core 2 further includes a fixed core 203 and a material distribution head 204. The spiral core 201, the core sleeve 202, the fixed core 203 and the material distribution head 204 are connected in sequence. The fixed core 203 and the material distribution head 204 are connected by a support plate 9. The driving part is located in the inner cavity of the support plate 9. The rotation axis 3 sequentially passes through the fixed core 203, the core sleeve 202 and the spiral core 201. A square section is provided on the rotation axis 3. The square section passes through the spiral core 201 and fits against the inner side wall of the spiral core 201. A locking bolt 10 is further provided at one end of the rotation axis 3 far from the driving part. The locking bolt 10 is threadedly connected to the rotation axis 3, and the end face of the locking bolt 10 abuts against the end face of the spiral core 201. A transmission gear 11 is sleeved on one end of the rotation axis 3 connected to the driving part. The transmission gear 11 is fixedly connected to the rotation axis 3, and the driving end of the driving part meshes with the transmission gear 11.
[0031] Specifically, it further includes a third bearing 12. The third bearing 12 is sleeved on the rotation axis 3. The outer ring of the third bearing 12 abuts against the inner side wall of the core sleeve 202. A limit protrusion 301 is provided on the rotation axis 3. A stepped surface is provided in the inner cavity of the core sleeve 202. The two end faces of the third bearing 12 respectively abut against the limit protrusion 301 and the stepped surface.
[0032] Specifically, it further includes an anti-wear gasket 13. The anti-wear gasket 13 is sleeved on the positioning part 6. The two ends of the anti-wear gasket 13 respectively abut against the end face of the core sleeve 202 and the end face of the spiral core 201. The first bearing 7 is located at one end of the positioning part 6 far from the anti-wear gasket 13.
[0033] Advantages of this embodiment: The axis of the groove 5 is spirally wound around the outer surface of the spiral die core 201. When the molten raw material advances along the groove 5, the spiral groove 5 can make the density of the raised spiral axis on the inner surface of the extruded pipe higher as the spiral die core 201 rotates. The setting of the diversion section 501 can more conveniently allow the molten raw material to flow into the groove 5. The rotating shaft 3 drives the spiral die core 201 to rotate through the square section, and the cross-section of the square section can also be replaced with any polygon. The nut of the locking bolt 10 abuts against the end face of the spiral die core 201, clamping the spiral die core 201 between the nut of the locking bolt 10 and the die core sleeve 202. The driving part drives the rotating shaft 3 to rotate through the transmission gear 11. There is no need for the driving part and the rotating shaft 3 to be arranged on the same axis, which can shorten the length of the mold. A third bearing 12 is sleeved on the rotating shaft 3, and the third bearing 12 is located between the first bearing 7 and the second bearing 8, which can further prevent the rotating shaft 3 from yawing during rotation. The setting of the wear-resistant gasket 13 can prevent the spiral die core 201 from wearing against the die core sleeve 202 during rotation. The first bearing 7 is located at one end of the positioning part 6 away from the wear-resistant gasket 13, so that the first bearing 7 is located at the position on the spiral die core 201 where wear is most likely to occur, further reducing the probability of yaw of the spiral die core 201.
[0034] Embodiment 3
[0035] An embodiment of a spiral pipe extrusion die for a PVC drainage pipe. On the basis of Embodiment 1 and Embodiment 2, as Figure 4 shown, the structure of the outer mold sleeve 1 is further defined.
[0036] Specifically, the outer mold sleeve 1 includes an outer mold cavity plate 101 and a discharge outer mold. The discharge outer mold is detachably connected to the outer mold cavity plate 101. The discharge outer mold includes a discharge plate 102, a discharge port 103 and a pressing plate 104. A positioning groove is provided on the discharge plate 102. The discharge port 103 is located in the positioning groove and fits against the side wall of the positioning groove. The outer side wall of the discharge port 103 is a stepped surface. The pressing plate 104 is sleeved on the stepped surface and abuts against the stepped surface. The pressing plate 104 is detachably connected to the discharge plate 102.
[0037] Specifically, the runner 4 includes a first contraction section 401 and a second contraction section 402. The first contraction section 401 is located between the mold core 2 and the outer mold cavity plate 101. In the plane where the axis of the mold core 2 lies, the angle between the outer side wall of the cross-section of the first contraction section 401 and the horizontal plane is 18°-30°; the angle between the inner side wall of the first contraction section 401 and the horizontal plane is 10°-15°. The second contraction section 402 is located between the mold core 2 and the discharge plate 102. In the plane where the axis of the mold core 2 lies, the angle between the outer side wall of the second contraction section 402 and the horizontal plane is 6°-12°, and the angle between the inner side wall of the second contraction section 402 and the horizontal plane is 170°-175°. In the plane where the axis of the mold core 2 lies, the cross-section angle of the material distributor head 204 is 60°-85°.
[0038] Beneficial effects of this embodiment: The outer discharge mold forms the runner 4 through the discharge port 103 of the discharge plate 102. The discharge port 103 is detachably connected to the discharge plate 102. When the mold needs to produce pipes with different thicknesses, discharge ports 103 of different specifications can be installed on the discharge plate 102 through the pressing plate 104, thereby changing the size of the discharge port 103 of the mold and making the mold have higher general applicability. Two contraction sections are provided in the runner 4 of this application, and the two contraction sections can compress the raw materials in the runner 4 twice, making the pipe more dense. When the angle between the outer side wall of the cross-section of the first contraction section 401 and the horizontal plane is 18°-30°; the angle between the inner side wall of the first contraction section 401 and the horizontal plane is 10°-15°, and the second contraction section 402 is located between the mold core 2 and the discharge plate 102. In the plane where the axis of the mold core 2 lies, when the angle between the outer side wall of the second contraction section 402 and the horizontal plane is 6°-12°, and the angle between the inner side wall of the second contraction section 402 and the horizontal plane is 170°-175°, the contraction effect of the raw materials is the best. When the cross-section angle of the material distributor head 204 is 60°-85°, the diversion effect of the mold inlet is the best.
[0039] Obviously, the above-mentioned embodiments of the present invention are merely examples for clearly explaining the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.
Claims
1. A spiral pipe extrusion die for PVC drain pipes, characterized in that, It includes an outer mold sleeve (1), a mold core (2), a rotating shaft (3) and a driving part located in the inner cavity of the outer mold sleeve (1). A runner (4) is formed between the outer mold sleeve (1) and the mold core (2). The mold core (2) includes a spiral mold core (201) and a mold core sleeve (202). One end of the spiral mold core (201) is provided with a groove (5) for forming a pipe rib, and the other end is provided with a positioning part (6) inserted into the inner cavity of the mold core sleeve (202). One end of the rotating shaft (3) passes through the mold core sleeve (202) and is fixedly connected to the spiral mold core (201), and the other end is connected to the driving end of the driving part. A first bearing (7) is sleeved on the positioning part (6), and the outer ring of the first bearing (7) abuts against the inner cavity of the mold core sleeve (202). A second bearing (8) is sleeved on one end of the rotating shaft (3) close to the driving part, and the outer ring of the second bearing (8) abuts against the inner side wall of the mold core (2).
2. The spiral pipe extrusion die of a PVC drain pipe according to claim 1, characterized in that, The axis of the groove (5) is spirally wound around the outer surface of the spiral mold core (201). One end of the groove (5) close to the mold core sleeve (202) is provided with a diversion section (501). There are several grooves (5), and several grooves (5) are arranged at equal circumferential intervals around the axis of the spiral mold core (201) with the rotating shaft (3) as the axis.
3. The spiral pipe extrusion die for a PVC drain pipe according to claim 1, characterized in that, The mold core (2) further includes a fixed mold core (203) and a material distributing head (204). The spiral mold core (201), the mold core sleeve (202), the fixed mold core (203) and the material distributing head (204) are connected in sequence. The fixed mold core (203) and the material distributing head (204) are connected by a support plate (9). The driving part is located in the inner cavity of the support plate (9). The rotating shaft (3) passes through the fixed mold core (203), the mold core sleeve (202) and the spiral mold core (201) in sequence.
4. The spiral tube extrusion die for a PVC drain pipe according to claim 3, characterized in that, The rotating shaft (3) is provided with a square section. The square section passes through the spiral mold core (201) and fits with the inner side wall of the spiral mold core (201). One end of the rotating shaft (3) far from the driving part is also provided with a locking bolt (10). The locking bolt (10) is threadedly connected to the rotating shaft (3), and the end face of the locking bolt (10) abuts against the end face of the spiral mold core (201).
5. The spiral pipe extrusion die for a PVC drain pipe according to claim 3, characterized in that, A transmission gear (11) is sleeved on one end of the rotating shaft (3) connected to the driving part. The transmission gear (11) is fixedly connected to the rotating shaft (3), and the driving end of the driving part meshes with the transmission gear (11).
6. The spiral tube extrusion die of a PVC drain pipe according to claim 3, characterized in that, It further includes a third bearing (12). The third bearing (12) is sleeved on the rotating shaft (3), and the outer ring of the third bearing (12) abuts against the inner side wall of the mold core sleeve (202). A limiting protrusion (301) is provided on the rotating shaft (3), and a step surface is provided in the inner cavity of the mold core sleeve (202). The two end faces of the third bearing (12) respectively abut against the limiting protrusion (301) and the step surface.
7. A spiral pipe extrusion die for a PVC drain pipe according to claim 1, characterized in that, It further includes an anti-wear gasket (13), the anti-wear gasket (13) is sleeved on the positioning portion (6), and two ends of the anti-wear gasket (13) are respectively abutted against the end face of the die core sleeve (202) and the end face of the spiral die core (201).
8. The spiral pipe extrusion die for a PVC drain pipe according to claim 7, characterized in that, The first bearing (7) is located at one end of the positioning portion (6) away from the anti-wear gasket (13).
9. The spiral tube extrusion die for a PVC drain pipe according to claim 1, characterized in that, The outer die sleeve (1) includes an outer die cavity plate (101) and a discharging outer die, the discharging outer die is detachably connected to the outer die cavity plate (101), the discharging outer die includes a discharging plate (102), a discharging port (103) and a pressing plate (104), a positioning groove is provided on the discharging plate (102), the discharging port (103) is located in the positioning groove and is in fit with the side wall of the positioning groove, the outer side wall of the discharging port (103) is a stepped surface, the pressing plate (104) is sleeved on the stepped surface and is abutted against the stepped surface, and the pressing plate (104) is detachably connected to the discharging plate (102).
10. A spiral pipe extrusion die for a PVC drain pipe according to claim 9, characterized in that, The runner (4) includes a first contraction section (401) and a second contraction section (402), the first contraction section (401) is located between the die core (2) and the outer die cavity plate (101), in the plane where the axis of the die core (2) is located, the included angle between the outer side wall of the cross section of the first contraction section (401) and the horizontal plane is 18° - 30°; the included angle between the inner side wall of the first contraction section (401) and the horizontal plane is 10° - 15°; The second contraction section (402) is located between the die core (2) and the discharging plate (102), in the plane where the axis of the die core (2) is located, the included angle between the outer side wall of the second contraction section (402) and the horizontal plane is 6° - 12°, and the included angle between the inner side wall of the second contraction section (402) and the horizontal plane is 170° - 175°.