Pipe extrusion die

Abstract

The utility model discloses a pipe extrusion die. The pipe extrusion die comprises a die body, a mandrel and a wall pressing piece, the mandrel is arranged in the die body, a runner is formed between the mandrel and the die body and used for extruding raw materials, and the raw materials leave the runner to form a pipe; the wall pressing piece is coaxially installed at the output end of the mandrel, an outer conical surface is arranged on the periphery of the wall pressing piece, and when the temperature of the mold is 220 DEG C, the end, close to the mandrel, of the outer conical surface is matched with the periphery of the output end of the mandrel, and the other end of the outer conical surface inclines outwards so that the inner wall of a pipe can be flattened. The included angle between the generatrix of the outer conical surface and the axis of the mandrel is larger than 1 degree and smaller than 3 degrees. The utility model provides a pipe extrusion die which can improve the smoothness of the inner wall of a pipe.

Description

Technical Field

[0001] The utility model relates to the technical field of pipe extrusion, in particular to a pipe extrusion die. Background Art

[0002] Existing pipe extrusion dies such as Figure 5 As shown, it includes a mold body 91 and a mandrel 92, the mandrel is arranged in the mold body, a flow channel 93 is formed between the mandrel and the mold body, and the raw material is extruded through the flow channel to form a tube 94. At that time, the inner wall smoothness of the tube output by the existing mold was poor, and the existing practice was to increase the pressure of the raw material and enlarge the mold, but this led to an increase in the cost of the mold. Utility Model Content

[0003] In order to solve the defect that the inner wall smoothness of the pipe output by the existing die is poor, the utility model provides a pipe extrusion die to improve the inner wall smoothness of the pipe.

[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0005] A pipe extrusion die comprises: a die body, a core shaft and a wall pressing piece; the core shaft is arranged in the die body, a flow channel is formed between the core shaft and the die body, the flow channel is used to extrude raw materials, and the raw materials leave the flow channel to form a pipe; the wall pressing piece is coaxially installed at the output end of the core shaft, and an outer cone surface is arranged on the outer periphery of the wall pressing piece. When the temperature of the die is 220 degrees Celsius, one end of the outer cone surface close to the core shaft cooperates with the outer periphery of the output end of the core shaft, and the other end of the outer cone surface is inclined outward to flatten the inner wall of the pipe, and the angle between the generatrix of the outer cone surface and the axis of the core shaft is greater than 1 degree and less than 3 degrees.

[0006] Through the above arrangement, firstly, the wall pressing member can flatten the inner wall of the pipe output from the flow channel to improve the smoothness of the inner wall of the pipe; secondly, it is convenient to transform and upgrade the existing mold, and the smoothness of the inner wall of the pipe can be increased without increasing or lengthening the mold.

[0007] Furthermore, the wall pressing piece is made of PTFE.

[0008] Through the above arrangement, the wall pressing part is wear-resistant, has a low friction coefficient, is resistant to high temperatures, and has high chemical stability.

[0009] Furthermore, the mandrel comprises: a mandrel body, a positioning column and a stud; the mandrel body is arranged in the mold body, a flow channel is formed between the mandrel body and the mold body, the wall pressing piece is attached to the output end of the mandrel body, and the end of the outer cone surface close to the flow channel is matched with the outer periphery of the output end of the mandrel body; the positioning column is coaxially fixedly connected to the output end of the mandrel body, and the positioning column passes through the wall pressing piece to prevent the wall pressing piece from moving radially; the stud is coaxially fixedly connected to the end of the positioning column away from the mandrel body;

[0010] The mold also includes a nut which is threadedly connected to the stud to lock the wall pressing piece onto the mandrel body.

[0011] Furthermore, a threaded hole is coaxially arranged at the output end of the core shaft, and the mold further comprises a bolt, which passes through the wall pressing piece and is threadedly connected to the threaded hole to lock the wall pressing piece on the core shaft.

[0012] Furthermore, the bolt includes: a threaded portion, a limiting portion and a head; the threaded portion is threadedly connected to the threaded hole; the limiting portion is coaxially fixedly connected to the threaded portion, the wall pressing piece is annular to form an inner conical surface parallel to the outer conical surface on the inner side, and the outer periphery of the limiting portion is fitted with the inner conical surface; the head is fixedly connected to an end of the limiting portion away from the threaded portion, and the head contacts the wall pressing piece to press the wall pressing piece onto the core shaft.

[0013] Through the above arrangement, firstly, the stability of the wall pressing member is increased; secondly, it is convenient to separate the bolt from the wall pressing member. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of a mold according to an embodiment.

[0015] Figure 2 It is a cross-sectional view of the mold of the embodiment.

[0016] Figure 3 for Figure 2 Enlarged view of point A.

[0017] Figure 4 The figure is a schematic diagram of the installation of the wall pressing member according to another embodiment.

[0018] Figure 5 A schematic diagram of an existing mold. DETAILED DESCRIPTION

[0019] The technical solution of the utility model is further specifically described below through embodiments and in conjunction with the accompanying drawings.

[0020] See also Figures 1 to 3 A pipe extrusion die comprises: a die body 2, a core shaft 3 and a wall pressing piece 4; the core shaft 3 is arranged in the die body 2, a flow channel 5 is formed between the core shaft 3 and the die body 2, the flow channel 5 is used to extrude the raw material, and the raw material leaves the flow channel 5 to form a pipe; the wall pressing piece 4 is coaxially installed at the output end of the core shaft 3, and the outer periphery of the wall pressing piece 4 is provided with an outer cone 41. When the temperature of the mold is 220 degrees Celsius, one end of the outer cone 41 close to the core shaft 3 cooperates with the outer periphery of the output end of the core shaft 3, and the other end of the outer cone 41 is inclined outward to flatten the inner wall of the pipe, and the angle j between the generatrix of the outer cone 41 and the axis of the core shaft 3 is greater than 1 degree and less than 3 degrees.

[0021] Through the above arrangement, firstly, the wall pressing member 4 can flatten the inner wall of the pipe output by the flow channel 5 to improve the smoothness of the inner wall of the pipe; secondly, it is convenient to transform and upgrade the existing mold, and the smoothness of the inner wall of the pipe can be increased without increasing or lengthening the mold.

[0022] In the present application, the mold body 2 can refer to the existing mold; the wall pressing member 4 is arranged outside the output end of the flow channel 5 to perform secondary processing on the pipe output from the flow channel 5; the ambient temperature for pipe extrusion is generally around 220 degrees Celsius, and the end of the outer cone 41 close to the core shaft 3 is matched with the outer periphery of the output end of the core shaft 3, that is, there is basically no gap between the wall pressing member 4 and the core shaft 3, and the pipe can move smoothly to the outer cone 41; the end of the outer cone 41 away from the flow channel 5 is inclined outward, and when the pipe moves along the outer cone 41, the outer cone 41 squeezes the inner wall of the pipe, flattens the inner wall of the pipe, and improves the smoothness of the inner wall of the pipe.

[0023] As an implementation method, the material of the wall pressing member 4 is PTFE.

[0024] Through the above arrangement, the wall pressing member 4 is wear-resistant, has a low friction coefficient, is resistant to high temperatures, and has high chemical stability.

[0025] As an implementation method, the mandrel 3 includes: a mandrel body 31, a positioning column 32 and a stud 33; the mandrel body 31 is arranged in the mold body 2, a flow channel 5 is formed between the mandrel body 31 and the mold body 2, the wall pressing member 4 is attached to the output end of the mandrel body 31, and the end of the outer cone 41 close to the flow channel 5 is matched with the outer periphery of the output end of the mandrel body 31; the positioning column 32 is coaxially fixedly connected to the output end of the mandrel body 31, and the positioning column 32 passes through the wall pressing member 4 to prevent the wall pressing member 4 from radial movement; the stud 33 is coaxially fixedly connected to the end of the positioning column 32 away from the mandrel body 31;

[0026] The mold further includes a nut 8 which is threadedly connected to the stud 33 to lock the wall pressing member 4 on the core shaft body 31 .

[0027] In another embodiment, see Figure 4 A threaded hole 6 is coaxially arranged at the output end of the core shaft 3 , and the mold further comprises a bolt 7 , which passes through the wall pressing member 4 and is threadedly connected to the threaded hole 6 to lock the wall pressing member 4 on the core shaft 3 .

[0028] In the present application, a threaded hole 6 can be directly processed at the output end of the existing mandrel 3, and then the adapted wall pressing member 4 can be installed on the output end of the mandrel 3 by means of bolts 7, thereby retaining the existing mandrel 3 and reducing the modification cost.

[0029] As an implementation method, the bolt 7 includes: a threaded portion 71, a limiting portion 72 and a head 73; the threaded portion 71 is threadedly connected to the threaded hole 6; the limiting portion 72 is coaxially fixedly connected to the threaded portion 71, and the wall pressing member 4 is annular to form an inner conical surface 42 parallel to the outer conical surface 41 on the inner side, and the outer periphery of the limiting portion 72 is in contact with the inner conical surface 42; the head 73 is fixedly connected to one end of the limiting portion 72 away from the threaded portion 71, and the head 73 contacts the wall pressing member 4 to press the wall pressing member 4 onto the core shaft 3.

[0030] Through the above arrangement, firstly, the stability of the wall pressing member 4 is increased; secondly, it is convenient to separate the bolt 7 from the wall pressing member 4.

[0031] In the present application, the limiting portion 72 prevents the wall pressing member 4 from moving radially; the head 73 presses the wall pressing member 4 against the end of the core shaft 3 to prevent the wall pressing member 4 from moving axially; when removing the wall pressing member 4, the mold is cooled to room temperature, and the head 73 is rotated with a wrench to remove the bolt 7 and the wall pressing member 4 from the core shaft 3. Due to the drop in temperature, the radius of the wall pressing member 4 shrinks, and the inner conical surface 42 of the wall pressing member 4 will slide relative to the outer periphery of the limiting portion 72, making it convenient to separate the wall pressing member 4 and the bolt 7.

[0032] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the claims attached to the utility model.

Claims

1. A pipe extrusion die, characterized in that: include: A mold body and a mandrel, wherein the mandrel is disposed in the mold body, a flow channel is formed between the mandrel and the mold body, and the flow channel is used to extrude raw materials, and the raw materials leave the flow channel to form a pipe; A wall pressing part, which is coaxially installed at the output end of the core shaft, and an outer cone is provided on the outer periphery of the wall pressing part. When the temperature of the mold is 220 degrees Celsius, one end of the outer cone close to the core shaft cooperates with the outer periphery of the output end of the core shaft, and the other end of the outer cone is inclined outward to flatten the inner wall of the pipe. The angle between the generatrix of the outer cone and the axis of the core shaft is greater than 1 degree and less than 3 degrees.

2. A pipe extrusion die according to claim 1, characterized in that: The material of the wall pressing member is PTFE.

3. A pipe extrusion die according to claim 1, characterized in that: The mandrel comprises: A mandrel body, wherein the mandrel body is disposed in the mold body, the flow channel is formed between the mandrel body and the mold body, the wall pressing member is attached to the output end of the mandrel body, and one end of the outer cone surface close to the flow channel is matched with the outer periphery of the output end of the mandrel body; A positioning column, wherein the positioning column is coaxially fixedly connected to the output end of the mandrel body, and the positioning column passes through the wall pressing member to prevent the wall pressing member from moving radially; A stud, the stud is coaxially fixedly connected to an end of the positioning column away from the core shaft body; The mold further comprises a nut which is threadedly connected to the stud to lock the wall pressing member on the core shaft body.

4. A pipe extrusion die according to claim 1, characterized in that: The output end of the core shaft is coaxially provided with a threaded hole, and the mold further comprises a bolt, which passes through the wall pressing member and is threadedly connected with the threaded hole to lock the wall pressing member on the core shaft.

5. A pipe extrusion die according to claim 4, characterized in that: The bolt comprises: a threaded portion, the threaded portion being threadedly connected to the threaded hole; A limiting portion, wherein the limiting portion is coaxially fixedly connected to the threaded portion, the wall pressing member is annular to form an inner conical surface parallel to the outer conical surface on the inner side, and the outer periphery of the limiting portion is in contact with the inner conical surface; The head portion is fixedly connected to an end of the limiting portion away from the threaded portion, and the head portion contacts the wall pressing member to press the wall pressing member onto the core shaft.

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