PVC wire tube mold matching structure

Abstract

The utility model discloses a PVC line pipe mould cooperation structure relates to the field of plastic processing, including the mouth mould and the core rod, the core rod is in the mouth mould, the mouth mould is cooperated with the front mould body, the cooperation surface of mouth mould and the front mould body is the inclined plane, the cooperation surface of core rod and the inner mould body is the inclined plane, the inner mould body with the same side cooperation of the front mould body with the support, the cooperation surface of inner mould body and the front mould body with the support is the inclined plane. Compared with the connection cooperation between the mouth mould and the shrinkage cover is set as the circular arc surface in the comparative technique, leads to the problem of material leakage, influences the precision of product. Through setting the main cooperation position of mould as the inclined plane cooperation, even if material wants to seep from the cooperation surface, because the contact area of inclined plane is big, the friction is big, and the material leakage is more difficult, improves the precision of product simultaneously, and sets up the screw hole that can adjust the gap on the mouth mould and the front mould body, thereby can fine tune the wall thickness of product.

Description

Technical Field

[0001] This utility model relates to the field of plastic processing, specifically to a PVC conduit mold fitting structure in extrusion molding equipment. Background Technology

[0002] In the field of PVC extruded pipes, the wall thickness deviation of the pipes is largely determined by the die mandrel and the precision of the die fit. The wall thickness deviation of the pipes directly affects their weight per meter and quality. Especially in the current pipeline die production environment, where the pursuit of high output and high quality is the goal, if the die precision cannot meet the requirements, it will not only affect the production quality, but also consume a lot of manpower and resources in adjusting the precision.

[0003] Traditional conduit mold fitting structures mostly use curved surfaces for the die opening, with a few using flat surfaces, while the remaining mold components are primarily flat surfaces. The curved surfaces at the die opening are prone to material leakage during production, making machining difficult. Furthermore, these fitting methods are susceptible to environmental influences during machining and assembly, resulting in low overall mold precision. Therefore, providing a high-precision mold fitting structure can significantly solve these problems.

[0004] As can be seen from the “PVC conduit mold” disclosed in announcement number CN207190230U, the connection transition between the die and the shrink sleeve is an arc surface, the fitting accuracy is low, and there is no ability to adjust the distance between the die and the shrink sleeve, so the wall thickness of the extruded tube cannot be adjusted. Utility Model Content

[0005] The purpose of this invention is to improve the overall installation accuracy of the conduit mold by installing inclined surfaces between the die and the front mold body, between the mandrel and the inner mold body, and between the inner mold body, the front mold body, and the support. This also results in a tighter fit, preventing material leakage. Another purpose of this invention is to create an adjustable gap between the die and the front mold body, allowing the die to move according to adjustments, thereby adjusting the wall thickness of the product extruded from the die.

[0006] The present invention achieves its purpose by adopting the following technical solutions.

[0007] A PVC conduit mold fitting structure includes a die and a mandrel. The mandrel is fitted inside the die. The die mates with a front mold body, and the mating surface between the die and the front mold body is inclined. The mandrel mates with an inner mold body, and the mating surface between the mandrel and the inner mold body is inclined. Both the inner mold body and the front mold body mate with the same side of a support, and the mating surfaces between the inner mold body and the front mold body and the support are inclined.

[0008] Furthermore, the end of the die is provided with a die bevel fitting section, and the upper part of the front die body is provided with a front die upper bevel fitting section, the front die upper bevel fitting section and the die bevel fitting section are in contact and fit together.

[0009] Furthermore, the inclined mating section of the die is an annular protrusion structure, the inclined mating section of the front mold body is a disc structure, and the inner sidewall of the inclined mating section of the die and the outer sidewall of the inclined mating section of the front mold body are inclined surfaces with equal inclination angles.

[0010] Furthermore, the inclined shaft section of the mandrel is engaged with the inclined groove section of the inner mold body.

[0011] Furthermore, the mandrel and the inner mold body have two mating points. Below the inclined shaft section of the mandrel and the inclined groove section of the inner mold body, the mandrel thread engages with the inner mold body thread.

[0012] Furthermore, at the mating end face of the die and the front mold body, there is an adjustment gap between the die and the front mold body.

[0013] Preferably, the die has a clearance adjustment hole on the outer side of the die inclined mating section, and a front mold body mating screw hole on the outer side of the front mold body. The axes of the die inclined mating section and the front mold body mating screw hole coincide. One side of the bracket inclined mating section mates with the inclined shaft section of the inner mold body, and the other side of the bracket inclined mating section mates with the inclined lower inclined mating section of the front mold body.

[0014] Preferably, the other side of the bracket is installed in conjunction with the fluid distributor and the rear mold body.

[0015] Furthermore, the fluid distribution is located in the space created by the cooperation and installation of the rear mold body and the bracket.

[0016] This utility model has the following beneficial effects:

[0017] Compared to the comparative technology where the connection between the die and the shrink sleeve is set as an arc surface, which easily leads to material leakage at the arc mating surface and affects the product's precision, this utility model sets the main mating position of the mold as an inclined surface. Even if material leaks from the mating surface, the large contact area and high friction of the inclined surface make leakage more difficult, while also improving the product's precision. Furthermore, adjustable screw holes are provided on the die and the front mold body to finely adjust the product's wall thickness. Attached Figure Description

[0018] Figure 1 This is a cross-sectional structural diagram of the present invention.

[0019] Figure 2 for Figure 1 A magnified view of a portion of point A in the middle.

[0020] Figure 3 for Figure 1 A magnified view of a section at point B in the middle.

[0021] Figure 4 for Figure 1 A magnified view of a section at point C.

[0022] In the diagram, 1-die, 11-adjusting wall clearance, 12-die inclined mating section, 13-clearance adjustment hole, 2-mandrel, 21-mandrel inclined shaft section, 22-mandrel thread, 3-inner mold body, 31-inner mold body inclined shaft section, 32-inner mold body thread, 33-inner mold body inclined groove section, 4-front mold body, 41-front mold body upper inclined mating section, 42-front mold body lower inclined mating section, 43-front mold body mating screw hole, 5-bracket, 51-bracket inclined mating section, 6-flow divider, 7-rear mold body. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0024] Example 1:

[0025] like Figures 1 to 4 As shown, a PVC conduit mold fitting structure includes a die 1 and a mandrel 2. The mandrel 2 is fitted inside the die 1. The die 1 fits with a front mold body 4, and the mating surface between the die 1 and the front mold body 4 is an inclined surface. The mandrel 2 fits with an inner mold body 3, and the mating surface between the mandrel 2 and the inner mold body 3 is an inclined surface. Both the inner mold body 3 and the front mold body 4 fit with the same side of a bracket 5, and the mating surfaces between the inner mold body 3 and the front mold body 4 and the bracket 5 are inclined surfaces.

[0026] The mandrel 2 is detachably installed inside the die 1. The annular gap between the mandrel 2 and the die 1 forms the forming channel for the extrusion of molten material into the pipe. The size of the gap between the mandrel 2 and the die 1 directly determines the cross-sectional profile and wall thickness of the pipe. Therefore, the dimensional accuracy of the mating gap between the mandrel 2 and the die 1 determines the uniformity of the wall thickness of the extruded pipe product.

[0027] The die 1 fits tightly with the front mold body 4. In the prior art, this fitting position is prone to material leakage, which can affect the product manufacturing accuracy. Therefore, the accuracy and tightness of this fitting interface are crucial for preventing molten material leakage and ensuring the stable and accurate positioning of the die 1. The mandrel 2 fits with the inner mold body 3 to precisely position and fix the mandrel 2. Since the mandrel 2 cannot be fixed to the die 1, but the mandrel 2 itself needs to maintain a stable distance from the die 1, the mandrel 2 is fixed to the inner mold body 3.

[0028] The inner mold body 3 remains relatively stationary with the die 1, thus ensuring that its axis is aligned with the die 1 and that it has high coaxiality. The inner mold body 3 and the front mold body 4 are uniformly fixedly installed on the same side of the bracket 5. The bracket 5, as an intermediate fixed connector, provides a stable positioning reference for the inner mold body 3 and the front mold body 4, thereby achieving relative fixation of the die 1 and the mandrel 2.

[0029] This utility model designs the mating surface between the die 1 and the front die body 4 as an inclined structure, such as... Figure 1 and Figure 2 As shown, specifically, the end of the die 1 is provided with a die bevel fitting section 12, which is a ring-shaped protrusion. Correspondingly, the upper part of the front mold body 4, that is, the end that connects with the die 1, is provided with a front mold body upper bevel fitting section 41, which is a disc-shaped structure. The inner sidewall of the die bevel fitting section 12 and the outer sidewall of the front mold body upper bevel fitting section 41 together form mutually fitting bevels. The inclination angles of the inner sidewall of the die bevel fitting section 12 and the outer sidewall of the front mold body upper bevel fitting section 41 are equal, so they can fit tightly together.

[0030] When die 1 is assembled into the front die body 4, a large-area close contact is formed between the inner wall of the inclined mating section 12 of the die and the outer wall of the inclined mating section 41 of the front die body. Compared with the traditional arc surface or flat surface mating, this inclined mating method not only provides a better self-centering effect and higher radial positioning accuracy, but also enhances the friction between the mating surfaces due to the significantly increased contact area. This makes it extremely difficult for molten material to leak from this mating surface, even under high extrusion pressure, i.e., the so-called overflow phenomenon, thereby improving the stability of the production process, the cleanliness of the product, and effectively reducing material loss.

[0031] Reference Figure 1 and Figure 3The mandrel 2 and the inner mold body 3 also utilize a beveled fit. Specifically, the mandrel 2 is machined with a beveled shaft section 21, which can be a cylindrical section with a certain taper on the mandrel body. The inner mold body 3 is provided with a precisely matched beveled groove section 33, which is an annular groove with a corresponding taper in the inner hole of the inner mold body 3. The close fit between the mandrel beveled shaft section 21 and the inner mold beveled groove section 33 ensures that the mandrel 2 has high positioning accuracy and stable support in the inner mold body 3, preventing the mandrel 2 from shaking during product extrusion and causing uneven product wall thickness. This is crucial for ensuring the uniformity of the final pipe wall thickness.

[0032] To further enhance the reliability and adjustability of the mandrel 2 within the inner mold body 3, this embodiment provides two mating points between the mandrel 2 and the inner mold body 3. In addition to the inclined surface mating between the mandrel inclined shaft section 21 and the inner mold body inclined groove section 33, below this inclined surface mating point, at the end furthest from the extrusion direction, the mandrel 2 is also provided with a mandrel thread 22, while the corresponding position on the inner mold body 3 is machined with a matching inner mold body thread 32. Through the threaded engagement of the mandrel thread 22 and the inner mold body thread 32, the mandrel 2 is not only firmly axially fixed to the inner mold body 3, effectively preventing it from shifting under the axial force of the extruded material, but also provides a means for fine-tuning the axial position of the mandrel 2.

[0033] like Figure 1 and Figure 4 As shown, the inner mold body 3 and the front mold body 4 are both installed on the same side of the support 5, facing the extrusion direction, and their mating surfaces with the support 5 are also designed with bevels. Specifically, the support 5 is provided with a support bevel mating section 51. According to its structural characteristics, the inner circumference of the support bevel mating section 51 is beveled with the inner mold body bevel shaft section 31 of the inner mold body 3, that is, the conical section of the outer circumference of the inner mold body 3; while on the other side, that is, the outer circumference of the support bevel mating section 51 is beveled with the front mold body lower bevel mating section 42 of the front mold body 4, that is, the conical section of the outer circumference of the front mold body lower bevel mating section 42.

[0034] By utilizing the centering characteristics of the inclined surface mating, the inner mold body 3 and the front mold body 4 can be stably and concentrically installed on the bracket 5. This provides a foundation for the die 1 to be installed on the front mold body 4 and the mandrel 2 to be installed on the inner mold body 3, and reduces positioning errors during installation. At the same time, the inclination angles of the inner and outer circumferential conical surfaces of the bracket inclined surface mating section 51 of the bracket 5 are different, so the inclination angles of the inclined surfaces that mate with the inner mold body 3 and the front mold body 4 and the bracket inclined surface mating section 51 are also different.

[0035] To adjust the wall thickness deviation of the extruded pipe, this invention incorporates a fine-tuning mechanism at the positions of the die 1 and the front die body 4. For example... Figure 2As shown, at the mating end faces of the die 1 and the front mold body 4, especially after the inclined mating section 12 of the die 1 and the inclined mating section 41 of the front mold body are mated, a small and adjustable axial gap is reserved between them, which is the wall adjustment gap 11. In order to adjust the product wall thickness using the wall adjustment gap 11, at least two gap adjustment holes 13 are evenly and symmetrically arranged on the outer circumference of the inclined mating section 12 of the die 1. Correspondingly, the outer side or flange surface of the front mold body 4 is provided with front mold body mating screw holes 43 that coincide with the axis of these gap adjustment holes 13. The front mold body mating screw holes 43 are threaded holes. By screwing in or out screws (not shown in the figure) into these paired screw holes, the operator can accurately control the height of both sides of the mating between the die 1 and the front mold body 4.

[0036] When the adjusting screw passes through the gap adjustment hole 13 (which serves as a through hole) and is screwed into the threaded hole 43 of the front mold body, tightening the screw on one side reduces the wall adjustment clearance 11 on that side. This causes the wall of the die 1 on the other side to move slightly towards the mandrel 2, thereby reducing the extrusion gap and making the tube wall thinner. Conversely, loosening the screw on one side increases the wall adjustment clearance 11 on that side. This causes the wall of the die 1 on the other side to move slightly away from the mandrel 2, thereby increasing the extrusion gap and making the tube wall thicker. Conversely, loosening the screw on one side increases the wall adjustment clearance 11 on that side. This causes the wall of the die 1 on the other side to move slightly away from the mandrel 2, thereby increasing the extrusion gap and making the tube wall thicker. Conversely, the wall of the die 1 on that side moves slightly towards the mandrel 2, making the tube wall thinner.

[0037] This design allows operators to quickly and easily fine-tune the pipe wall thickness. The gap adjustment hole 13 and the front mold body mating screw hole 43 are set to precisely control the small wall thickness deviations that may occur during the production process, ensuring that the final product wall thickness accuracy always meets the preset standard, and effectively compensate for fluctuations that may be caused by changes in production conditions such as material batch differences and slight mold wear, thereby avoiding the problems of difficult, time-consuming and labor-intensive adjustment of traditional pipe extrusion molds.

[0038] On the other side of the support 5, away from the die 1, it is installed in conjunction with the distributor 6 and the rear die 7. The distributor 6 is typically placed within the internal space formed by the rear die 7 and the support 5. The rear die 7 is generally connected to the extruder head and is responsible for receiving molten PVC material from the extruder. The core function of the distributor 6 is to effectively divert the molten material, initially separating it from a solid flow into a tubular, hollow flow state, ensuring that the material can smoothly and uniformly enter the annular cavity formed by the mandrel 2 and the die 1. This plays a crucial role in ensuring the consistency of material flow across the pipe cross-section and avoiding wall thickness deviations and internal stress concentrations caused by uneven flow rates.

[0039] In operation, the molten PVC material enters from the rear mold body 7, is evenly distributed by the distributor 6, and then flows sequentially through the inner mold body 3 and the front mold body 4 fixed by the support 5. Finally, it is extruded from the annular gap formed between the die 1 and the mandrel 2, and cooled and shaped into a pipe.

[0040] The beneficial effects of this utility model are reflected in the following aspects:

[0041] Firstly, by employing inclined plane fits at the mating positions of die 1 and front die 4, mandrel 2 and inner die 3, inner die 3 and support 5, and front die 4 and support 5, the concentricity and positioning accuracy between components are significantly improved. The self-centering characteristic of the inclined plane fit helps reduce assembly errors, enabling the overall die to achieve a high level of precision, thus providing a good guarantee for the dimensional stability and wall thickness uniformity of the extruded pipe.

[0042] Secondly, this structure offers superior leak-proof performance compared to existing technologies. The beveled fit increases the contact area, and its structural features and tight fit between the mating surfaces generate greater friction and a better sealing effect. This effectively improves the material leakage problem that easily occurs in high-pressure areas such as dies with traditional arc or flat mating surfaces, helping to ensure a clean production environment and efficient material utilization.

[0043] Furthermore, the convenient wall thickness adjustment capability is an innovation of this invention. Utilizing the wall thickness adjustment gap 11 between the die 1 and the front die body 4, and the adjustment mechanism comprised of the gap adjustment hole 13 and the screw hole 43 fitting with the front die body, operators can easily and precisely fine-tune the pipe wall thickness. This adjustment capability is primarily used to precisely control and correct minor deviations in pipe wall thickness during production, ensuring that the product meets preset precision standards. It can also effectively address wall thickness variations caused by material characteristic fluctuations, die wear, or environmental changes, thereby contributing to improved product qualification rates.

[0044] In addition, the mandrel 2 and the inner mold body 3 adopt multiple fixing methods, including inclined surface fit and threaded fit, to ensure that the structure has good stability and reliability. This allows the mandrel to maintain good stability and positioning accuracy even under high temperature and high pressure working environment, effectively preventing loosening or eccentricity.

[0045] These improvements collectively bring about tangible cost-effectiveness and efficiency gains: due to the higher precision of the molds, reduced material leakage, and easier adjustment, it helps to reduce defective products caused by mold problems and save raw materials; at the same time, it can also reduce the manpower and time that operators need to spend on mold debugging and maintenance to a certain extent.

[0046] In summary, this utility model improves the fitting accuracy of the PVC conduit mold by designing an inclined surface fit, which also reduces the difficulty of positioning and fitting the various components during mold installation. The inclined surface fit also reduces the possibility of material overflow during production. Compared with the existing technology that uses a circular arc segment for fit, the processing accuracy requirements are relatively low, the fit is easier, and it is less likely to overflow.

Claims

1. A PVC conduit mold fitting structure, characterized in that, It includes a die (1) and a mandrel (2). The mandrel (2) is fitted inside the die (1). The die (1) is fitted with a front mold body (4). The mating surface between the die (1) and the front mold body (4) is an inclined surface. The mandrel (2) is fitted with an inner mold body (3). The mating surface between the mandrel (2) and the inner mold body (3) is an inclined surface. The inner mold body (3) and the front mold body (4) are both fitted with the same side of a bracket (5). The mating surfaces between the inner mold body (3) and the front mold body (4) and the bracket (5) are inclined surfaces.

2. The PVC conduit mold fitting structure according to claim 1, characterized in that, The end of the die (1) is provided with a die inclined surface fitting section (12), and the upper part of the front die body (4) is provided with a front die upper inclined surface fitting section (41). The front die upper inclined surface fitting section (41) and the die inclined surface fitting section (12) are in contact and fit together.

3. The PVC conduit mold fitting structure according to claim 2, characterized in that, The inclined mating section (12) of the die is an annular protrusion structure, and the inclined mating section (41) of the front mold body is a disc structure. The inner sidewall of the inclined mating section (12) of the die and the outer sidewall of the inclined mating section (41) of the front mold body are inclined surfaces with equal inclination angles.

4. A PVC conduit mold fitting structure according to claim 1, 2, or 3, characterized in that, The inclined shaft section (21) of the mandrel (2) is engaged with the inclined groove section (33) of the inner mold body (3).

5. The PVC conduit mold fitting structure according to claim 4, characterized in that, The mandrel (2) and the inner mold body (3) have two mating parts: the mandrel inclined shaft section (21) and the inner mold body inclined groove section (33) are mated below the inclined surface; the mandrel thread (22) of the mandrel (2) is threadedly engaged with the inner mold body thread (32) of the inner mold body (3).

6. A PVC conduit mold fitting structure according to claim 1, 2, 3, or 5, characterized in that, At the mating end face of the die (1) and the front mold body (4), there is an adjustment gap (11) between the die (1) and the front mold body (4).

7. The PVC conduit mold fitting structure according to claim 2, characterized in that, On the die (1), a clearance adjustment screw hole (13) is provided on the outer side of the die inclined mating section (12), and a front mold body mating screw hole (43) is provided on the outer side of the front mold body (4). The axes of the die inclined mating section (12) and the front mold body mating screw hole (43) coincide.

8. A PVC conduit mold fitting structure according to claim 1, 2, 3, 5, or 7, characterized in that, One side of the bracket inclined surface mating section (51) of the bracket (5) is mated with the inclined surface of the inner mold body inclined shaft section (31) of the inner mold body (3), and the other side of the bracket inclined surface mating section (51) of the bracket (5) is mated with the inclined surface of the lower inclined surface mating section (42) of the front mold body (4).

9. A PVC conduit mold fitting structure according to claim 1, 2, 3, 5, or 7, characterized in that, The other side of the bracket (5) is installed in conjunction with the fluid distributor (6) and the rear mold body (7).

10. The PVC conduit mold fitting structure according to claim 9, characterized in that, The fluid separator (6) is located in the space created by the cooperation of the rear mold (7) and the bracket (5).

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