A mold structure for improving inner and outer walls of pipes

Abstract

The invention discloses a mold structure for improving the inner and outer walls of a pipe, comprising a core rod, a die and a heating ring, the core rod and the die are concentrically distributed, the die is located on the periphery of the core rod, a discharge channel is formed between the inner periphery of the die and the outer periphery of the core rod, the end face of the die is fitted with the heating ring, the core rod comprises an extension portion exceeding the end face of the die, the extension portion is concentrically distributed with the core rod, the outer peripheral wall of the extension portion comprises a flaring portion 1, the diameter of the flaring portion 1 gradually increases from close to the die end to away from the die, the slope ɑ of the flaring portion 1 is 1.5-2 degrees, the axial length L1 of the flaring portion 1 is 6.5-7 mm, the inner peripheral wall of the heating ring comprises an inclined portion 1, the diameter of the inclined portion 1 gradually increases from close to the die end to away from the die, the diameter of the inclined portion 1 close to the die end is equal to that of the die, the slope b of the inclined portion 1 is 1.6-2.1 degrees, and the slope b of the inclined portion 1 is greater than the slope ɑ of the flaring portion 1. The die of the present invention does not accumulate precipitates, and the flatness of the inner wall of the product is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of pipe moulds, and in particular to a mould structure for improving the inner and outer walls of a pipe. Background Art

[0002] The current molds used to manufacture pipes have the core rod and die flush at the discharge end, which has the following problems:

[0003] 1. When the production speed is fast, the inner wall of the pipe will have obvious wrinkles and the inner wall is not smooth enough.

[0004] Second, if the precipitated material sticks to the die port, it will cause fine line problems on the pipe product, seriously affecting the appearance of the product. Frequent shutdown for cleaning is required, resulting in low efficiency and a lot of waste. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art and provide a mold structure for improving the inner and outer walls of a pipe, so that no deposits will accumulate on the die and the flatness of the inner wall of the product is improved.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A mold structure for improving the inner and outer walls of a pipe, comprising a core rod, a die and a heating ring, the core rod and the die being concentrically distributed, the die being located on the periphery of the core rod, a discharge channel being formed between the inner circumferential wall of the die and the outer circumferential wall of the core rod, an annular heating ring being fitted on the end face of the die, the core rod comprising an extension portion extending beyond the end face of the die, the extension portion being concentrically distributed with the core rod, the outer circumferential wall of the extension portion comprising a flaring portion 1, the diameter of the flaring portion 1 gradually increasing from close to the die end to away from the die end, the slope ɑ of the flaring portion 1 being 1.5-2 degrees, the axial length L1 of the flaring portion 1 being 6.5-7 mm, the inner circumferential wall of the heating ring comprising an inclined portion 1, the diameter of the inclined portion 1 gradually increasing from close to the die end to away from the die end, the diameter of the inclined portion 1 near the die end being equal to that of the die, the slope b of the inclined portion 1 being 1.6-2.1 degrees, and the slope b of the inclined portion 1 being greater than the slope ɑ of the flaring portion 1.

[0008] The extended portion includes a rounded corner portion, and the rounded corner portion connects an end portion of the expanded portion away from the die and an outer edge of the end surface of the extended portion.

[0009] The length L2 of the extended portion is 9.5-10 mm, and the axial length of the rounded portion is L2-L1=2.5-3.5 mm.

[0010] The radius R of the rounded corner is 2.5-3.5 mm.

[0011] The slope ɑ of the flared portion 1 is 1.8 degrees, the axial length L1 of the flared portion 1 is 6.5 mm, the length L2 of the extended portion is 9.5 mm, the axial length of the rounded portion is L2-L1=3 mm, and the radius R of the rounded portion is 3 mm.

[0012] The axial length L4 of the first oblique portion is 7.5-8 mm, and the axial length L4 of the first oblique portion is greater than the axial length L1 of the first flared portion.

[0013] The axial length L4 of the first inclined portion is 7.5 mm.

[0014] The slope b of the first slope is 2.0 degrees.

[0015] The inner peripheral wall of the heating ring includes an equal diameter portion and a second inclined portion. The first inclined portion, the equal diameter portion and the second inclined portion are distributed in sequence, and the second inclined portion and the first inclined portion are symmetrically distributed.

[0016] The thickness L3 of the heating ring is 25-50 mm, and the equal-diameter portion always has the same diameter, which is equal to the diameter of the outer end of the first inclined portion.

[0017] The beneficial effects of the present invention are:

[0018] 1. After the die end face is heated, the precipitate can be pulled out along with the pipe after being heated, which will not cause accumulation at the die. The die will not accumulate precipitates, and there is no need to stop the machine for cleaning, and no waste will be generated.

[0019] 2. The extended part protrudes from the end face of the core rod, and the inclined flaring and rounded corners can effectively improve the inner wall of the pipe product, and the flatness of the inner wall of the product is improved. After the inclined flaring is used to smooth the inner wall of the pipe, the extrusion volume of the equipment can be increased, and the production capacity can be increased by at least 1 ton / day (originally 13-14 tons, now increased to 14-15 tons / day).

[0020] 3. When the raw material barrel temperature is raised to above 170 degrees, the inner wall of the product will be uneven due to over-plasticization of the material. Now that the inner wall problem has been solved, the barrel temperature can be raised to 180 degrees. When the barrel temperature rises, the torque of the screw can be effectively reduced, thereby effectively avoiding the problem of screw breakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the present invention;

[0022] Figure 2 for Figure 1 Enlarged view of point A in the middle;

[0023] Figure 3 It is a front view of the heating ring of the present invention;

[0024] Figure 4It is a structural schematic diagram of the extension portion of the present invention;

[0025] Figure 5 Schematic diagram of the structure of the inner ring wall of the heating ring of the present invention.

[0026] In the figure: core rod 1, extension part 11, flared part 111, rounded part 112, die 2, heating ring 3, inclined part 1 31, equal diameter part 32, inclined part 2 33, socket 34, screw hole 35, thermocouple hole 36. DETAILED DESCRIPTION

[0027] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0028] like Figures 1 to 5 As shown, a mold structure for improving the inner and outer walls of a pipe comprises a core rod 1, a die 2 and a heating ring 3. The core rod 1 and the die 2 are concentrically distributed, the die 2 is located on the periphery of the core rod 1, and a discharge channel is formed between the inner circumferential wall of the die 2 and the outer circumferential wall of the core rod 1. The structural position relationship between the core rod 1 and the die 2 in this part is the existing technology.

[0029] Reference Figure 1 、 Figure 2 The core rod 1 includes an extended portion 11 that exceeds the end face of the outlet die 2 (the end for discharging the material). The extended portion 11 is concentrically distributed with the core rod 1. The extended portion 11 specifically refers to the portion of the core rod 1 whose length exceeds the right end of the outlet die 2, because the end faces of the two are flush in the prior art.

[0030] Reference Figure 4 The outer peripheral wall of the extended portion 11 includes a flared portion 111 and a rounded portion 112. The diameter of the flared portion 111 gradually increases from the end close to the die 2 to the end away from the die 2. The diameter of the flared portion 111 near the end of the die 2 is the same as the diameter of the right end of the die 2, and then the diameter of the flared portion 111 increases directly to the right.

[0031] Reference Figure 4 The length L2 of the extension portion 11 is 9.5-10 mm, and the length L2 of the extension portion 11 is preferably 9.5 mm.

[0032] Reference Figure 4The slope ɑ of the flared portion 111 is 1.5-2 degrees, preferably 1.8 degrees. The axial length L1 of the flared portion 111 is 6.5-7 mm, preferably 6.5 mm. Assuming ɑ is 1.8 degrees and L1 is 6.5 mm, the height of the right end of the flared portion 111 above its left end is 6.5*tan1.8=0.21 mm. The extended portion 11 is obtained by extending one end of the core rod 1 by 9.5 mm. The initial section of the extended portion 11, i.e., the flared portion 111, is inclined and enlarged, and the maximum enlargement is 0.21 mm. The flared portion 111 smoothes the inner wall of the extruded pipe, and since the slope of the flared portion 111 is 1.8 degrees, the axial length L1 is 6.5 mm, and the maximum inclination enlargement is 0.21 mm, the overall slope of the smoothing process is small, the travel length is short, the maximum size increase is limited, and it is not abrupt. The smoothing process is smooth and effective, and will not affect the performance parameters of the pipe.

[0033] Reference Figure 4 , the fillet portion 112 connects the end (right end) of the flared portion 111 away from the die 2 and the outer edge of the end face of the extension portion 11. The axial length of the fillet portion 112 is L2-L1=2.5-3.5mm, and the preferred axial length of the fillet portion 112 is L2-L1=3mm. The radius R of the fillet portion 112 is 2.5-3.5mm, and the preferred radius R of the fillet portion 112 is 3mm. The axial length of the fillet portion 112 is determined by the axial length of the entire extension portion 11 and the axial length of the flared portion 111. The extension portion 11 cannot exceed the end of the die 2 too much, otherwise it will cause defects and deformation on the inner wall of the pipe. Therefore, the axial length of the extension portion 11 is controlled within 10mm, and the extension portion 11 cannot be too short, otherwise it will not play the role of smoothing the inner wall of the pipe. Therefore, the minimum length of the extension portion 11 is mm. After the axial length of the extension portion 11 is determined, the axial length of the flared portion 111 accounts for approximately two-thirds of the entire extension portion 11. The axial length of the flared portion 111 is crucial, so its length cannot be too short. If it is too short, the inner wall of the pipe cannot be properly smoothed. If it is too long, it will occupy the space of the rounded portion 112. Without the rounded portion 112, the inner wall of the pipe will suddenly lose support after gradually expanding through the flared portion 111, causing local deformation and affecting product quality. The design of the rounded portion 112 provides a buffer and slight support for the pipe after passing through the flared portion 111, preventing sudden force changes and deformation.

[0034] Reference Figure 4 If the radius R of the rounded corner portion 112 is less than 2.5 mm, the smaller the radius R, the Figure 4The rounded corner 112 in the figure needs to protrude to the upper right corner (not shown). At this time, there is a process of continuing to rise from the highest point of the right end of the flared part 111 to the rounded corner 112, which is obviously not in line with the intention of the present invention. If the radius R of the rounded corner 112 is greater than 3.5mm, the larger the radius R, the Figure 4 The fillet 112 in the pipe needs to be indented toward the lower left corner (not shown). This will create a flat arc. In this case, there is a sudden descent from the highest point on the right end of the flared portion 111 into the fillet 112, which can cause local deformation and affect product quality. Therefore, the radius R of the fillet 112 is preferably 3 mm. This creates a perfect transition between the fillet 112 and the flared portion 111. There is no upward movement from the highest point on the right end of the flared portion 111 into the fillet 112, nor is there a significant downward movement within a very short axial length, which helps maintain the shape of the pipe.

[0035] Reference Figure 1 、 Figure 2 The end surface of the die 2 is fitted with a ring-shaped heating ring 3.

[0036] Reference Figure 3 The heating coil 3 is provided with a socket 34, a screw hole 35, and a thermocouple hole 36. The heating coil 3 is an annular structure as a whole. A heating wire is installed inside the heating coil 3. The heating coil 3 is heated by energizing the heating wire. The socket 34 is used to connect the power supply and provide a sensor interface. The heating coil 3 is installed on the right end face of the die 2 by screwing a bolt into the screw hole 35. The thermocouple hole 36 is used to install a temperature detection thermocouple, which can be used to detect the heating temperature in real time. The precipitate outside the right end face of the die 2 is melted by heating and pulled out together with the pipe. There is no need to stop the machine for cleaning and no waste is generated.

[0037] Reference Figure 1 、 Figure 2 、 Figure 5 The inner circumferential wall of the heating coil 3 includes a first bevel portion 31, a constant diameter portion 32, and a second bevel portion 33. The diameter of the first bevel portion 31 gradually increases from the end closest to the die 2 to the end farther away from the die 2. The diameter of the first bevel portion 31 near the die 2 is equal to the diameter of the die 2. The slope b of the first bevel portion 31 is 1.6-2.1 degrees, and the slope b of the first bevel portion 31 is greater than the slope ɑ of the flared portion 111. Preferably, the slope b of the first bevel portion 31 is 2.0 degrees. The inclined portion 31 is almost parallel to the flared portion 111, but is not actually parallel. Instead, the inclination of the inclined portion 31 is slightly larger. This is because there is precipitate outside the right end of the die 2. Although the precipitate produced at these moments is small, it always exists. After the precipitate melts, it is combined with the pipe. Therefore, it is necessary to slightly expand the channel after extrusion. The slope b of the inclined portion 31 is designed to be greater than the slope ɑ of the flared portion 111, which is equivalent to expansion to accommodate the melted precipitate.

[0038] Reference Figure 5 The axial length L4 of the inclined portion 31 is 7.5-8 mm, preferably 7.5 mm. Based on a b of 2.0 degrees and L4 of 7.5 mm, the right end of the inclined portion 31 is 0.26 mm higher than the left end by 7.5*tan2.0. This 0.26 mm is 0.05 mm greater than the 0.21 mm at the maximum slope of the flared portion 111. While this value is small, it is sufficient to accommodate the molten precipitate.

[0039] Reference Figure 5 The axial length L4 of the inclined portion 31 is greater than the axial length L1 of the flared portion 111. L4 is 7.5 mm and L1 is 6.5 mm, which is 1 mm larger than L1. Because the tube tends to expand after passing through the flared portion 111, the 1 mm extra length at the end of the inclined portion 31 compared to the end of the flared portion 111 mitigates this expansion, making the tube extrusion deformation more natural and smooth, reducing the occurrence of defects.

[0040] Reference Figure 5 The bevel 1 31, the equal diameter portion 32 and the bevel 2 33 are distributed in sequence, and the bevel 2 33 and the bevel 1 31 are symmetrically distributed. The bevel 2 33 and the bevel 1 31 are symmetrical about the center of the equal diameter portion 32. The equal diameter portion 32 is always the same diameter, and the diameter of the equal diameter portion 32 is equal to the diameter of the outer end of the bevel 1 31. That is, the diameter of the equal diameter portion 32 is equal to the diameter of the right end of the bevel 1 31, and the diameter of the equal diameter portion 32 is equal to the diameter of the left end of the bevel 2 33. The diameter of the bevel 2 33 gradually decreases from left to right, and the diameter of the right end of the bevel 2 33 is equal to the diameter of the left end of the bevel 1 31, that is, equal to the inner diameter of the die 2. The equal diameter portion 32 plays the role of connecting the bevel 2 33 and the bevel 1 31. The bevel 2 33 allows the pipe to return to the outer diameter at the time of initial extrusion, which is convenient for the subsequent operation of entering the sizing sleeve, so that the overall size of the pipe is not affected after the extension portion 11 and the heating ring 3 are added.

[0041] The thickness L3 of the heating ring 3 is 25-50 mm, and the above solutions are all data when L3 is 25 mm.

[0042] The thickness of the heating coil 3 is determined by the size of the pipe. The DN110 pipe uses an aluminum cast heating coil 3 with a thickness of 25 mm, and the DN160 pipe uses an aluminum cast heating coil 3 with a thickness of 50 mm. The structural difference between the heating coils 3 with different thicknesses lies in the length of the equal diameter part 32. The equal diameter part 32 of the heating coil 3 with a thickness of 50 mm is 25 mm longer than that of the heating coil with a thickness of 25 mm.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A mold structure for improving the inner and outer walls of a pipe, characterized by: The invention comprises a core rod (1), a die (2) and a heating ring (3), wherein the core rod (1) and the die (2) are concentrically distributed, the die (2) is located on the periphery of the core rod (1), a discharge channel is formed between the inner peripheral wall of the die (2) and the outer peripheral wall of the core rod (1), the end face of the die (2) is fitted with an annular heating ring (3), the core rod (1) comprises an extension portion (11) extending beyond the end face of the die (2), the extension portion (11) is concentrically distributed with the core rod (1), the outer peripheral wall of the extension portion (11) comprises an expansion portion (111), the diameter of the expansion portion (111) increases from near The diameter of the flared portion (111) gradually increases from the end close to the die (2) to the end away from the die (2), the slope ɑ of the flared portion (111) is 1.5-2 degrees, and the axial length L1 of the flared portion (111) is 6.5-7 mm. The inner peripheral wall of the heating ring (3) includes a slope (31), and the diameter of the slope (31) gradually increases from the end close to the die (2) to the end away from the die (2). The diameter of the slope (31) close to the die (2) is the same as that of the die (2), and the slope b of the slope (31) is 1.6-2.1 degrees. The slope b of the slope (31) is greater than the slope ɑ of the flared portion (111).

2. A mold structure for improving the inner and outer walls of a pipe according to claim 1, characterized in that: The extended portion (11) includes a rounded corner portion (112), and the rounded corner portion (112) connects the end of the expanded portion (111) away from the die (2) and the outer edge of the end surface of the extended portion (11).

3. A mold structure for improving the inner and outer walls of a pipe as claimed in claim 2, characterized in that: The length L2 of the extended portion (11) is 9.5-10 mm, and the axial length of the rounded corner portion (112) is L2-L1=2.5-3.5 mm.

4. A mold structure for improving the inner and outer walls of a pipe as claimed in claim 2, characterized in that: The radius R of the rounded corner (112) is 2.5-3.5 mm.

5. A mold structure for improving the inner and outer walls of a pipe as claimed in claim 3, characterized in that: The slope ɑ of the flared portion (111) is 1.8 degrees, the axial length L1 of the flared portion (111) is 6.5 mm, the length L2 of the extended portion (11) is 9.5 mm, the axial length of the rounded portion (112) is L2-L1=3 mm, and the radius R of the rounded portion (112) is 3 mm.

6. A mold structure for improving the inner and outer walls of a pipe as claimed in claim 1, characterized in that: The axial length L4 of the inclined portion 1 (31) is 7.5-8 mm, and the axial length L4 of the inclined portion 1 (31) is greater than the axial length L1 of the flared portion 1 (111).

7. A mold structure for improving the inner and outer walls of a pipe as claimed in claim 6, characterized in that: The axial length L4 of the inclined portion 1 (31) is 7.5 mm.

8. A mold structure for improving the inner and outer walls of a pipe as claimed in claim 1, characterized in that: The slope b of the inclined portion 1 (31) is 2.0 degrees.

9. A mold structure for improving the inner and outer walls of a pipe as claimed in claim 1, characterized in that: The inner peripheral wall of the heating ring (3) includes an equal diameter portion (32) and a second inclined portion (33), wherein the first inclined portion (31), the equal diameter portion (32) and the second inclined portion (33) are distributed in sequence, and the second inclined portion (33) and the first inclined portion (31) are symmetrically distributed.

10. A mold structure for improving the inner and outer walls of a pipe according to claim 9, characterized in that: The thickness L3 of the heating ring (3) is 25-50 mm, and the equal-diameter portion (32) always has the same diameter, and the diameter of the equal-diameter portion (32) is equal to the diameter of the outer end of the inclined portion (31).

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