Plastic pipe injection mold with large bending-diameter ratio

Abstract

The utility model discloses an injection mold for a plastic pipe with a large bending diameter ratio, which is characterized in that an upper mold base is provided with a first accommodating cavity, an upper mold core is positioned in the first accommodating cavity and is fixed with the upper mold base, the upper mold base and the upper mold core are provided with first injection molding channels, and the upper mold core is provided with an arc-shaped upper mold cavity; a second containing cavity is formed in the lower mold base, the lower mold core is located in the second containing cavity and matched with the lower mold base, and a second injection molding channel is formed in the lower mold core; an arc-shaped lower mold cavity is formed in the lower mold core; a notch communicated with the second containing cavity is formed in the lower die base, the supporting base is matched with the notch, one end of the connecting base is fixed to the supporting base, the connecting base is matched with the lower die cavity, and after the connecting column is fixed to the other end of the connecting base, the connecting column is suspended in the lower die cavity. The utility model is favorable for reducing the manufacturing difficulty of the die.

Description

Technical Field

[0001] The utility model relates to the technical field of plastic products, in particular to an injection mould for a plastic pipe with a large bend-to-diameter ratio. Background Art

[0002] In recent years, plastic elbow joints have been widely used in the fields of construction, water supply and drainage, electrical appliances, telecommunications, transportation, papermaking, etc. In various types of plastic pipe networks, elbow joints are very critical components. Due to the special stress conditions and high stress levels at the bends of the pipes, the most easily worn parts of the pipes are also at the bends. With the influence of factors such as medium pressure and flow rate, they show irregular and uneven wear, which makes the bends easy to rupture and cause serious consequences.

[0003] As an important component in the pipeline system, plastic elbow joints are attracting more and more attention. In engineering, elbows with a bend-to-diameter ratio (R / D) greater than 2.5 are often called large bend-to-diameter ratio elbows. Compared with ordinary plastic elbow joints, large bend-to-diameter ratio plastic elbow joints have the advantages of reducing pipeline fluid resistance, increasing flow coefficient, reducing pressure loss, and improving pipeline safety. They have great application prospects in various fluid pipelines and pressure pipelines. Further research on elbows found that their bend-to-diameter ratio is a very critical parameter. At the same pipe diameter, as the bend-to-diameter ratio increases, the flow coefficient increases, and the maximum wear decreases. Considering factors such as economy and mold manufacturing, it is usually relatively appropriate to take a bend-to-diameter ratio of 2.5 to 3.5. However, the research on molding molds and molding processes for elbow joints of 90° and above is relatively complicated. Therefore, a mold device that conforms to actual production is required, and injection molding process conditions that meet the high quality requirements of the product are required to obtain plastic elbow joint products with good comprehensive performance and high precision.

[0004] Plastic elbow joints are usually made by injection molding, and the injection molding process is extremely complex. Researchers need to study the molding rules through a large number of numerical simulations and molding process experiments. Obtaining a reasonable combination of process parameters is an important way to produce high-quality and high-precision products. Domestic experts have found through long-term research that the injection temperature has a very prominent effect on its strength, with an influence rate of nearly 66%. At the same time, analysis of injection molded product samples found that weld marks have a great influence on the appearance quality and mechanical properties of the product. In the injection molding process, melt, mold temperature and injection pressure are the main factors affecting weld marks.

[0005] At present, since the mold manufacturing accuracy of the above-mentioned elbow joints is difficult to meet the corresponding requirements, it is easy to cause incomplete injection or weld mark defects during injection molding, and the production efficiency is very low, which is a difficult problem that plastic product manufacturers need to solve. Utility Model Content

[0006] The utility model provides a plastic pipe injection mold with a large bend-to-diameter ratio. The utility model is beneficial to reducing the difficulty of manufacturing the mold.

[0007] The technical solutions to the above problems are as follows:

[0008] A large bending-diameter ratio plastic pipe injection mold comprises an upper mold assembly and a lower mold assembly matched with the upper mold assembly, wherein the upper mold assembly comprises an upper mold base and an upper mold core, wherein the upper mold base is provided with a first accommodating cavity, the upper mold core is located in the first accommodating cavity and is fixed to the upper mold base, the upper mold base and the upper mold core are provided with a first injection channel, and the upper mold core is provided with an arc-shaped upper mold cavity;

[0009] The lower mold assembly includes a lower mold base and a lower mold core. The lower mold base is provided with a second accommodating cavity. The lower mold core is located in the second accommodating cavity and cooperates with the lower mold base. The lower mold core is provided with a second injection channel. The lower mold core is provided with an arc-shaped lower mold cavity.

[0010] It also includes a mold core, which includes a support seat, a connecting seat, and a curved connecting column. The lower mold seat is provided with a notch connected to the second accommodating cavity. The support seat cooperates with the notch. One end of the connecting seat is fixed to the support seat, and the connecting seat cooperates with the lower mold cavity. After the connecting column is fixed to the other end of the connecting seat, the connecting column is suspended in the lower mold cavity.

[0011] When demolding is required after the injection molding is completed, the support seat is driven to move by the driver, driving the connecting seat and the connecting column to move, thereby separating the mold core from the large bend ratio plastic tube. If the resistance is large during the demolding process, since the mold core of the utility model is composed of a first connector, a second connector, and a third connector, after the injection molding is completed, when the mold core needs to be separated from the large bend ratio plastic tube, first release the connection between the first connector and the connecting seat, and then apply a pulling force to the external support block to move the first connector, the second connector, and the third connector. When the plug on the first connector is exposed to the outside of the large bend ratio plastic tube, take out the plug and the connecting screws in turn to separate the first connector from the second connector. According to the above method, take out the second connector and the third connector in turn. Since the mold core of the utility model is composed of a first connector, a second connector, and a third connector, and is supported in sequence by an outer support block and an inner support block, it is only necessary to ensure the processing accuracy of the first connector, the second connector, and the third connector to improve the accuracy of the mold. The manufacturing accuracy of a single connector is easier to ensure than the accuracy of the entire arc-shaped mold core. Moreover, the greatest advantage of this structure is that the maximum curvature of the plastic tube can reach 180°. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a stereoscopic diagram of the large bend-to-diameter ratio plastic pipe injection mold of the utility model.

[0013] Figure 2 A three-dimensional view of the upper mold assembly.

[0014] Figure 3 A three-dimensional view of the lower mold assembly.

[0015] Figure 4 For Figure 3 A schematic diagram with some parts hidden on the basis of the model.

[0016] Figure 5 This is the main view of the mold core after hiding some parts.

[0017] Figure 6 This is a three-dimensional image of the mold core with some parts hidden.

[0018] Figure 7 This is a cross-sectional view of the mold core.

[0019] Markings in the accompanying drawings: large bend-diameter ratio plastic tube A, upper mold base 1, upper mold core 2, first injection channel 3, upper mold cavity 4.

[0020] A lower mold base 11 , a notch 11 a , a lower mold core 12 , a second injection channel 13 , and a lower mold cavity 14 .

[0021] Support seat 31, connecting seat 32, connecting column 33, first connecting body 33a, second connecting body 33b, third connecting body 33c, outer support block 33d, inner support block 33e, connecting screw 33f, plug 33g, first through hole 33h, second through hole 33i, third hole 33j, through hole 33k, guide rail 34, mounting plate 35, linear drive 36. DETAILED DESCRIPTION

[0022] The utility model is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0023] like Figures 1 to 7 The utility model provides a large bend-diameter ratio plastic pipe injection mold, comprising an upper mold assembly, a lower mold assembly, and a mold core. The lower mold assembly cooperates with the upper mold assembly, and the mold core cooperates with the upper mold assembly and the lower mold assembly respectively. Each part and the relationship between the parts are described in detail below.

[0024] The upper mold assembly includes an upper mold base 1 and an upper mold core 2. The upper mold base 1 is provided with a first accommodating cavity. The upper mold core 2 is located in the first accommodating cavity and fixed to the upper mold base 1. The upper mold base 1 and the upper mold core 2 are provided with a first injection channel 3. The upper mold core 2 is provided with an arc-shaped upper mold cavity 4.

[0025] The lower mold assembly includes a lower mold base 11 and a lower mold core 12. The lower mold base 11 is provided with a second accommodating cavity. The lower mold core 12 is located in the second accommodating cavity and cooperates with the lower mold base 11. The lower mold core 12 is provided with a second injection channel 13. The lower mold core 12 is provided with an arc-shaped lower mold cavity 14. The second injection channel 13 is connected to the lower mold cavity 14. The arc of the lower mold cavity 14 can be 45 to 180 degrees. For example, the arc of the lower mold cavity 14 can be 45 degrees, 90 degrees, 135 degrees, and 180 degrees. When the upper mold assembly and the lower mold assembly are molded together, the upper mold cavity 4 cooperates with the lower mold cavity 14, and the first injection channel 3 cooperates with the second injection channel 13.

[0026] The mold core includes a support seat 31, a connecting seat 32, and a curved connecting column 33. The lower mold base 11 is provided with a notch 11a connected to the second accommodating cavity. The support seat 31 cooperates with the notch 11a. One end of the connecting seat 32 is fixed to the support seat 31. The connecting seat 32 cooperates with the lower mold cavity 14. After the connecting column 33 is fixed to the other end of the connecting seat 32, the connecting column 33 is suspended in the lower mold cavity 14. The curvature of the connecting column 33 matches the curvature of the lower mold cavity 14. Through the action of the support seat 31 and the connecting seat 32, the connecting column 33 is suspended in the lower mold cavity 14. After the injection molding material enters the lower mold cavity 14, the injection molding material wraps the mold core, and after cooling, a plastic tube with a large bending-diameter ratio is formed.

[0027] The connecting column 33 includes a first connecting body 33a, a second connecting body 33b, a third connecting body 33c, an outer supporting block 33d, an inner supporting block 33e, a connecting screw 33f, and a plug 33g. The cross-sections of the first connecting body 33a, the second connecting body 33b, and the third connecting body 33c are fan-shaped. The first connecting body 33a, the second connecting body 33b, and the third connecting body 33c are provided with a first through hole 33h and a second through hole 33i that penetrate the axial end surface, and the axial end surface of the third connecting body 33c is provided with a third hole 33j. The circumferential surfaces of the first connecting body 33a, the second connecting body 33b, and the third connecting body 33c are all provided with through holes 33k that match the first through hole 33h and the second through hole 33i.

[0028] An outer support block 33d is provided in the first through hole 33h on the first connecting body 33a, an inner support block 33e is provided in the second through hole 33 on the first connecting body 33a, one end of the outer support block 33d on the first connecting body 33a is inserted into the connecting seat 32 and connected by a connecting screw 33f. One end of the inner support block 33e on the first connecting body 33a is inserted into the second through hole 33h on the second connecting body 33b, an outer support block 33d is provided in the first through hole 33h on the second connecting body 33b, and one end of the outer support block 33d on the second connecting body 33b is inserted into the third hole 33j on the third connecting body 33c.

[0029] Since one end of the outer support block 33d on the first connecting body 33a is inserted into the connecting seat 32 and connected by the connecting screw 33f, the first connecting body 33a is supported on the connecting seat 32 by the outer support block 33d. Since one end of the inner support block 33e on the first connecting body 33a is inserted into the second through hole 33h on the second connecting body 33b, the second connecting body 33b is supported by the first connecting body 33a through the inner support block 33e. Since one end of the outer support block 33d on the second connecting body 33b is inserted into the third hole 33j on the third connecting body 33c, the third connecting body 33c is supported by the second connecting body 33b through the outer support block 33d.

[0030] After a plurality of connecting screws 33f are respectively passed through the through holes 33k on the first connecting body 33a, the second connecting body 33b and the third connecting body 33c, they cooperate with the outer support blocks 33d and / or the inner support blocks 33e on each second connecting body 33b to position the outer support blocks 33d and the inner support blocks 33e.

[0031] The outer support block 33d and the inner support block 33e are arranged one above the other, and both the outer support block 33d and the inner support block 33e are provided with waist-shaped holes, and the connecting screws 33f pass through the waist-shaped holes. For the connecting screws 33f located in two adjacent outer support blocks 33d and inner support blocks 33e, the connecting screws 33f passing through the outer support block 33d form a positioning for the end of the adjacent inner support block 33e, and the connecting screws 33f passing through the inner support block 33e form a positioning for the end of the adjacent outer support block 33d.

[0032] A plurality of plugs 33g are used to seal the through holes 33k on the first connector 33a, the second connector 33b and the third connector 33c. The plugs 33g can prevent the injection material from entering the through holes 33k, wherein the through holes 33k are stepped holes, and after the plugs 33g are matched with the through holes 33k, the plugs 33g are pressed against the steps of the through holes 33k.

[0033] In this embodiment, the first connector 33a is composed of two sections and arranged symmetrically, the second connector 33b is composed of two sections and arranged symmetrically, and the third connector 33c is composed of two sections and arranged symmetrically. Therefore, the arc of the entire connecting column 33 is 180 degrees. The two sections of the third connector 33c do not need to be connected by the outer support block 33d and / or the inner support block 33e. The preferred method is that the two sections of the third connector 33c can be connected by magnetic attraction, which makes demoulding simpler.

[0034] In this embodiment, one end of the first connector 33a is matched with one end of the second connector 33b through a concave-convex structure, and the other end of the second connector 33b is matched with one end of the third connector 33c through a concave-convex structure. For example, one end of the first connector 33a is provided with a protrusion, and one end of the second connector 33b is provided with a recessed portion. The protrusion on the first connector 33a and the recessed portion on the second connector 33b form a concave-convex match, and the other end of the second connector 33b and the third connector 33c are similarly matched by this structure. Through the concave-convex matching structure, the tightness of the match between the two adjacent connectors can be increased, and the gap between the two can be reduced, which is convenient for subsequent demoulding.

[0035] The first connector 33a, the second connector 33b and the third connector 33c are all magnetic, and the first connector 33a and the second connector 33b are attracted to each other by magnetism, and the third connector 33c and the second connector 33b are attracted to each other by magnetism. The magnetic attraction force can increase the support force between two adjacent connectors.

[0036] The mold core also includes a driver for driving the support seat 31 to move in the notch 11a, and the driver is fixed to the support seat 31. The driver includes a guide rail 34, a mounting plate 35, and a linear driver 36. One end of the guide rail 34 is located in the notch 11a and is fixed to the lower mold seat 11. The support seat 31 is slidably matched with the guide rail 34. The mounting plate 35 is fixed to the other end of the guide rail 34. The linear driver 36 is fixed to the mounting plate 35. The power output end of the linear driver 36 passes through the mounting plate 35 and is connected to the support seat 31.

[0037] When demolding is required after the injection molding is completed, the support seat 31 is driven by the driver to move, driving the connecting seat 32 and the connecting column 33 to move, so that the mold core is separated from the large bending ratio plastic tube A. If the resistance is large during the demolding process, since the mold core of the utility model is composed of a first connector 33a, a second connector 33b, and a third connector 33c, after the injection molding is completed, when the mold core needs to be separated from the large bending ratio plastic tube A, the connection between the first connector 33a and the connecting seat 32 is first released, and then a pulling force is applied to the outer support block 33d to move the first connector 33a, the second connector 33b, and the third connector 33c. When the plug on the first connector 33a is exposed to the outside of the large bending ratio plastic tube A, the plug 33g and the connecting screw 33f are removed in turn to separate the first connector 33a from the second connector 33b. According to the above method, the second connector 33b and the third connector 33c are removed in turn.

[0038] Finally, it should be noted that the above embodiments are merely preferred embodiments of the present invention and are used to illustrate the technical solution of the present invention, rather than limiting it, let alone limiting the protection scope of the present invention. Although the utility model has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features therein may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solution from the protection scope of the claims.

Claims

1. A large bending-diameter ratio plastic tube injection mold, comprising an upper mold assembly and a lower mold assembly cooperating with the upper mold assembly, the upper mold assembly comprising an upper mold base (1) and an upper mold core (2), the upper mold base (1) being provided with a first accommodating cavity, the upper mold core (2) being located in the first accommodating cavity and being fixed to the upper mold base (1), the upper mold base (1) and the upper mold core (2) being provided with a first injection channel (3), and the upper mold core (2) being provided with an arc-shaped upper mold cavity (4); The lower mold assembly comprises a lower mold base (11) and a lower mold core (12); the lower mold base (11) is provided with a second accommodating cavity; the lower mold core (12) is located in the second accommodating cavity and cooperates with the lower mold base (11); the lower mold core (12) is provided with a second injection channel (13); and the lower mold core (12) is provided with an arc-shaped lower mold cavity (14); It is characterized in that The mold core also includes a support seat (31), a connecting seat (32), and a connecting column (33) bent in an arc shape. The lower mold seat (11) is provided with a notch (11a) connected to the second accommodating cavity. The support seat (31) cooperates with the notch (11a). One end of the connecting seat (32) is fixed to the support seat (31). The connecting seat (32) cooperates with the lower mold cavity (14). After the connecting column (33) is fixed to the other end of the connecting seat (32), the connecting column (33) is suspended in the lower mold cavity (14).

2. The large bend-to-diameter ratio plastic pipe injection mold according to claim 1, characterized in that: The connecting column (33) comprises a first connecting body (33a), a second connecting body (33b), a third connecting body (33c), an outer supporting block (33d), an inner supporting block (33e), connecting screws (33f), and a plug (33g); The cross-sections of the first connecting body (33a), the second connecting body (33b) and the third connecting body (33c) are fan-shaped; the first connecting body (33a), the second connecting body (33b) and the third connecting body (33c) are provided with a first through hole (33h) and a second through hole (33i) penetrating the axial end surface; and the axial end surface of the third connecting body (33c) is provided with a third hole (33j); The first connecting body (33a), the second connecting body (33b) and the third connecting body (33c) are all provided with through holes (33k) that match the first through hole (33h) and the second through hole (33i) on their circumferential surfaces; An outer support block (33d) is provided in a first through hole (33h) on the first connecting body (33a), an inner support block (33e) is provided in a second through hole (33i) on the first connecting body (33a), and one end of the outer support block (33d) on the first connecting body (33a) is inserted into the connecting seat (32) and connected via a connecting screw (33f); One end of an inner support block (33e) located on the first connecting body (33a) is inserted into a second through hole (33i) on the second connecting body (33b), an outer support block (33d) is provided in the first through hole (33h) on the second connecting body (33b), and one end of the outer support block (33d) located on the second connecting body (33b) is inserted into a third hole (33j) on the third connecting body (33c); A plurality of connecting screws (33f) are respectively passed through the through holes (33k) on the first connecting body (33a), the second connecting body (33b) and the third connecting body (33c), and then cooperate with the outer supporting blocks (33d) and / or the inner supporting blocks (33e) on each second connecting body (33b) to position the outer supporting blocks (33d) and the inner supporting blocks (33e); and a plurality of plugs (33g) are used to seal the through holes (33k) on the first connecting body (33a), the second connecting body (33b) and the third connecting body (33c).

3. The large bend-to-diameter ratio plastic pipe injection mold according to claim 2, characterized in that: The first connector (33a) has two sections and is symmetrically arranged, the second connector (33b) has two sections and is symmetrically arranged, and the third connector (33c) has two sections and is symmetrically arranged.

4. The large bend-to-diameter ratio plastic pipe injection mold according to claim 2, characterized in that: One end of the first connector (33a) cooperates with one end of the second connector (33b) via a concave-convex structure, and the other end of the second connector (33b) cooperates with one end of the third connector (33c) via a concave-convex structure.

5. The large bend-to-diameter ratio plastic pipe injection mold according to claim 2, characterized in that: The first connector (33a), the second connector (33b), and the third connector (33c) are all magnetic; the first connector (33a) and the second connector (33b) are attracted to each other through magnetism, and the third connector (33c) and the second connector (33b) are attracted to each other through magnetism.

6. The large bend-to-diameter ratio plastic tube injection mold according to any one of claims 1 to 5, characterized in that: The mold core also includes a driver for driving the support seat (31) to move in the notch (11a), and the driver is fixed to the support seat (31).

7. The large bend-to-diameter ratio plastic pipe injection mold according to claim 6, characterized in that: The driver comprises a guide rail (34), a mounting plate (35), and a linear driver (36); one end of the guide rail (34) is located in the notch (11a) and is fixed to the lower die base (11); the support base (31) is slidably matched with the guide rail (34); the mounting plate (35) is fixed to the other end of the guide rail (34); the linear driver (36) is fixed to the mounting plate (35); and a power output end of the linear driver (36) passes through the mounting plate (35) and is connected to the support base (31).

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