Split structure lower die and wheel low pressure casting die

Abstract

The present invention belongs to the technical field of wheel casting, and provides a split structure lower mold and a wheel low-pressure casting mold. The top of the cavity of the lower mold is provided with a horizontal parting surface, and the parting surface divides the lower mold into an upper part and a lower part. The lower part is in a circular ring shape. The present application reasonably designs the lower mold, sets the parting surface at the position where the overall thickness of the lower mold changes sharply, and splits the lower mold, thereby ensuring the uniformity of the thickness of the lower mold casting cavity body to the greatest extent, reducing the large internal stress generated by the lower mold in a hot state, improving a series of effects caused by the thermal deformation of the lower mold on the product, improving the wheel casting size accuracy and the life of the lower mold, further improving product quality, and reducing mold costs.

Description

Technical Field

[0001] The present application relates to the technical field of wheel casting, and in particular to a split structure lower mold and a wheel low-pressure casting mold. Background Art

[0002] Low-pressure casting refers to a casting method in which the mold is generally placed above a sealed crucible, and compressed air is passed into the crucible to create a low pressure (0.06-0.15MPa) on the surface of the molten metal, causing the molten metal to rise from the riser to fill the mold and control solidification.

[0003] The lower die of the wheel casting mold is used to shape the front of the wheel. During the low-pressure casting process, the lower die is thermally deformed due to thermal stress. The thermal deformation of the lower die not only affects the accuracy of the front shape of the wheel, but also has a serious impact on the axial processing size of the wheel center hole and the finishing processing amount of the front finishing product. Summary of the invention

[0004] The embodiment of the present application provides a split structure lower mold and a wheel low-pressure casting mold. Through the reasonable design of the lower mold, the large internal stress generated by the lower mold in a hot state is reduced, and the serious influence of thermal deformation of the lower mold on the wheel shape and casting size during casting is improved, thereby improving the casting accuracy of the wheel and the life of the mold.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] In a first aspect, a split structure lower mold is provided, wherein a cavity is arranged at the bottom of the lower mold, and a horizontal parting surface is arranged along the top of the cavity between the outer edge of the cavity and the outer edge of the lower mold, and the parting surface divides the lower mold into an upper part and a lower part, and the lower part is in a circular ring shape.

[0007] In some embodiments, at the parting surface, a heat insulation groove is provided on the upper body or the lower body.

[0008] In some embodiments, the thermal insulation groove is generally annular in shape and surrounds the cavity.

[0009] In some embodiments, the upper body and the lower body are provided with corresponding flat-head threaded holes, and the flat-head threaded holes cooperate with bolts to connect and fix the upper body and the lower body.

[0010] In some embodiments, the upper body and the lower body are provided with corresponding pin holes, and the pin holes cooperate with positioning pins to position the upper body and the lower body circumferentially to prevent the upper body and the lower body from rotating circumferentially.

[0011] In some embodiments, one of the locating pin hole of the upper body and the locating pin hole of the lower body is waist-shaped and the other is circular.

[0012] In some embodiments, the upper body and the lower body are matched in a stepped manner, and the step is arranged on the inner side of the parting surface.

[0013] In some embodiments, a circle of bosses is provided on the inner side of the top surface of the lower body, and a depression is correspondingly provided on the lower end surface of the upper body, and the bosses and the depression form a stepped fit.

[0014] In some embodiments, more than one circle of deep holes and shallow holes are provided on the bottom surface of the upper split body; the number of the deep holes and shallow holes in each circle is equal, and the deep holes and shallow holes are arranged at intervals.

[0015] In the second aspect, an embodiment of the present application provides a low-pressure casting mold for a wheel, comprising an upper mold, a side mold and a lower mold, wherein the upper mold, the side mold and the lower mold form a casting cavity of the wheel, and the lower mold is the split structure lower mold described in any of the above embodiments.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] Provided are a split structure lower mold and a wheel low-pressure casting mold, wherein a horizontal parting surface is provided on the top of the cavity of the lower mold, and the parting surface divides the lower mold into an upper part and a lower part, and the lower part is in a circular ring shape. The present application reasonably designs the lower mold, sets the parting surface at the position where the overall thickness of the lower mold changes sharply, and splits the lower mold, thereby ensuring the uniformity of the thickness of the lower mold casting cavity body to the greatest extent, reducing the large internal stress generated by the lower mold in a hot state, improving a series of effects of thermal deformation of the lower mold on the product, improving the wheel casting dimensional accuracy and the life of the lower mold, further improving product quality, and reducing mold costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 It is a structural schematic diagram of a split structure lower mold in one or more embodiments of the present application.

[0020] Figure 2 It is a schematic structural diagram of an upper split body of a split structure lower mold in one or more embodiments of the present application.

[0021] Figure 3 It is a bottom view of the upper split of a split-structure lower mold in one or more embodiments of the present application.

[0022] Figure 4 It is a structural schematic diagram of the lower split of a split-structure lower mold in one or more embodiments of the present application.

[0023] Figure 5 It is a top view of the lower split of a split structure lower mold in one or more embodiments of the present application.

[0024] Figure 6 It is a structural schematic diagram of a wheel low-pressure casting mold in one or more embodiments of the present application.

[0025] Among them: 1-lower mold, 2-cavity, 3-parting surface, 4-upper split, 5-lower split, 6-insulation groove, 7-flat head threaded hole, 8-fastening bolt, 9-pin hole, 10-locating pin, 11-deep hole, 12-shallow hole, 13-upper mold, 14-side mold. DETAILED DESCRIPTION

[0026] The terms "first", "second", "third" and "fourth" etc. in the specification and claims of the present application and the drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0027] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0028] The present application has found that when the wheel is cast at low pressure, the temperature is lower at the part far from the gate, and the temperature is higher as it is closer to the gate, forming a certain temperature difference. In addition, the thickness difference of each part of the lower mold is large, which leads to a large thermal stress inside the lower mold, causing the lower mold to be thermally deformed. This thermal deformation has a serious impact on the product modeling, related casting dimensions and machining dimensions. In order to reduce the thermal stress generated inside the lower mold, a split structure lower mold is provided in one embodiment of the present application, wherein a cavity is provided at the bottom of the lower mold, and a horizontal parting surface is provided along the top of the cavity between the outer edge of the cavity and the outer edge of the lower mold, and the parting surface divides the lower mold into an upper part and a lower part, and the lower part is in a circular ring shape. In this embodiment, the parting surface is provided at the part where the overall thickness of the lower mold changes sharply, so as to split the lower mold, thereby ensuring the uniformity of the thickness of the lower mold casting cavity body to the greatest extent, reducing the large internal stress generated by the lower mold in the hot state, improving a series of effects caused by the thermal deformation of the lower mold on the product, improving the wheel casting dimensional accuracy and the life of the lower mold, further improving product quality, and reducing mold costs.

[0029] In order to reduce heat conduction between the upper and lower parts and facilitate the implementation of the casting process, in some embodiments, a heat insulation groove is provided on the upper part or the lower part at the parting surface. In order to achieve a better heat insulation effect, in some embodiments, the heat insulation groove is preferably in an annular shape as a whole, surrounding the cavity.

[0030] In order to ensure a safe distance between the threaded hole and the mold cavity, and at the same time ensure that the upper and lower parts of the lower mold are connected and fastened by the fastening bolts, in some embodiments, the upper and lower parts are correspondingly provided with flat-head threaded holes, and the flat-head threaded holes cooperate with bolts to connect and fix the upper and lower parts.

[0031] In order to prevent the circumferential rotation between the upper and lower parts of the lower mold, in some embodiments, pin holes are correspondingly opened on the upper and lower parts, and the pin holes cooperate with positioning pins to position the upper and lower parts circumferentially to prevent the upper and lower parts from rotating circumferentially.

[0032] Taking into account the deformation of the positioning pin due to heat and to facilitate the installation of the positioning pin for positioning, in some embodiments, one of the positioning pin hole of the upper body and the positioning pin hole of the lower body is waist-shaped and the other is circular.

[0033] In order to radially position the upper and lower parts of the lower mold and ensure a good positioning effect, in some embodiments, the upper and lower parts are matched in a stepped manner. Considering the temperature difference and thermal expansion difference of the lower mold of the upper and lower parts, the stepped platform is arranged on the inner part of the parting surface. In order to facilitate disassembly and assembly, in some embodiments, a circle of bosses is arranged on the inner side of the top surface of the lower part, and a depression is arranged correspondingly on the lower end surface of the upper part, and the bosses and the depression form a stepped match.

[0034] In order to reduce the thermal stress generated inside the lower mold and accelerate heat dissipation, in some embodiments, more than one circle of deep holes and shallow holes are opened on the bottom surface of the upper split body; the number of deep holes and shallow holes in each circle is equal, and the deep holes and shallow holes are arranged at intervals.

[0035] In the second aspect, the embodiment of the present application provides a low-pressure casting mold for a wheel, including an upper mold, a side mold and a lower mold, wherein the upper mold, the side mold and the lower mold form a casting cavity for the wheel, and the lower mold is a split structure lower mold as described in any of the above embodiments. The low-pressure casting mold for a wheel in this embodiment has a simple structure, and solves the current situation of thermal deformation of the lower mold caused by thermal stress on the basis of ensuring the low-pressure casting process, which not only improves the casting accuracy of the front shape of the wheel, but also solves the problems of the out-of-tolerance casting size of the front wheel, the out-of-tolerance axial machining size of the wheel center hole, and the deviation of the finishing machining amount of the front finishing product, thereby further improving the product quality and reducing the mold cost.

[0036] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0037] Embodiment 1:

[0038] In this embodiment 1, a split structure lower mold 1 is provided, such as Figure 1-5As shown in , a cavity 2 is provided at the bottom of the lower mold 1, and a horizontal parting surface 3 is provided along the top of the cavity 2 between the outer edge of the cavity 2 and the outer edge of the lower mold 1. The parting surface 3 divides the lower mold into an upper part 4 and a lower part 5. The lower part 5 is in the shape of a circular ring. At the parting surface 3, a heat insulation groove 6 is provided on the upper part 4 or the lower part 5. The heat insulation groove 6 is in the shape of a circular ring as a whole, surrounding the cavity 2. Flat-head threaded holes 7 are provided on the upper part 4 and the lower part 5, and 8 flat-head threaded holes 7 are provided on the upper and lower parts 4 and 5 respectively. The flat-head threaded holes 7 cooperate with 8 fastening bolts 8 to connect and fix the upper part 4 and the lower part 5. The upper body 4 and the lower body 5 are provided with two pin holes 9 correspondingly at the top and bottom. The pin holes 9 cooperate with two positioning pins 10 to position the upper body 4 and the lower body 5 circumferentially to prevent the upper body 4 and the lower body 5 from rotating circumferentially. Figure 3 and 5 It can be seen that the positioning pin hole 9 of the lower body 5 is circular, and the positioning pin hole 9 of the upper body 4 is waist-shaped. The upper body 4 and the lower body 5 are matched in a stepped manner, and the step is arranged on the inner side of the parting surface 3. A circle of bosses is arranged on the inner side of the top surface of the lower body 5, and a concave part is arranged correspondingly on the lower end surface of the upper body 4, and the bosses and the concave part form a stepped match. Figure 3 As shown in the figure, two circles of deep holes 11 and shallow holes 12 are opened on the bottom surface of the upper body 4. The deep holes 11 and the shallow holes 12 are connected to the cavity 2, and the number of the deep holes 11 and the shallow holes 12 on each circle is equal to 5, and the deep holes 11 and the shallow holes 12 are arranged at intervals.

[0039] In some other embodiments, the positioning pin hole of the upper body 4 may be circular, and the positioning pin hole 9 of the lower body 5 may be waist-shaped.

[0040] In this embodiment 1, the lower mold is split by setting a parting surface at the position where the overall thickness of the lower mold changes sharply, thereby ensuring the uniformity of the thickness of the lower mold casting cavity body to the greatest extent, reducing the large internal stress generated by the lower mold in a hot state, and improving a series of effects of the thermal deformation of the lower mold on the product, thereby solving the problems of wheel front shape and casting size out-of-tolerance caused by thermal deformation of the lower mold, improving the wheel casting size accuracy and the life of the lower mold, further improving product quality, and reducing mold costs.

[0041] Example 2

[0042] In this embodiment 2, a wheel low-pressure casting mold is provided, such as Figure 6As shown in the figure, it includes an upper mold 13, a side mold 14 and a lower mold 1, and the upper mold 13, the side mold 14 and the lower mold 1 form a casting cavity of the wheel, and the lower mold is the split structure lower mold 1 described in the above embodiment 1. A low-pressure casting mold for a wheel in this embodiment is adopted, which has a simple structure. On the basis of ensuring the low-pressure casting process, it solves the current situation of thermal deformation of the lower mold caused by thermal stress, and not only improves the casting accuracy of the front shape of the wheel, but also solves the problems of the out-of-tolerance casting size of the front wheel, the out-of-tolerance axial machining size of the wheel center hole, and the deviation of the finishing machining amount of the front finishing product. This invention greatly improves the front shape accuracy of the wheel, the casting size accuracy and the life of the lower mold, and many machining size problems caused by the thermal deformation of the lower mold have also been well solved, thereby further improving the product quality and reducing the mold cost.

[0043] Example 3

[0044] In Example 3, an 18-inch wheel mold is selected. Figure 6 As shown in the figure, the upper mold 13, the side mold 14 and the lower mold 1 are included, and the upper mold 13, the side mold 14 and the lower mold 1 form a casting cavity for the wheel. The lower mold 1 adopts the split structure lower mold in the above embodiment 1, and the parting surface 3 of the lower mold is set at the position where the overall thickness of the lower mold 1 changes sharply. The thickness of the lower split 5 is 45mm. Figure 1 Schematic form, to ensure the uniformity of the thickness of the lower mold casting cavity body to the greatest extent.

[0045] like Figure 4 As shown in FIG, a heat insulation groove 6 with a depth of 1 mm and a width of 20 mm is processed on the horizontal parting surface 3 where the lower part 5 is located.

[0046] like Figure 2 As shown in , the threaded hole corresponding to the M16 high-strength fastening bolt 8 (GB / 70M16x35) connecting and fastening the upper part 4 and the lower part 5 is a flat-head threaded hole 7. The upper part 4 and the lower part 5 of the lower mold 1 are connected and fastened with 8 evenly distributed M16 high-strength fastening bolts 8. Generally, the bottom of the flat-head threaded hole 7 is ≥6mm away from the mold cavity, and the thread engagement length is ≥16mm. The M16 threaded hole is 10mm away from the mold cavity, and the thread engagement length is 20mm.

[0047] like Figure 3 and 5As shown in the figure, two locating pins 10 are used to locate the upper part 4 and the lower part 5 to prevent the circumferential rotation between the upper and lower parts of the lower mold 1. The two locating pins 10 are symmetrical and distributed 20 degrees symmetrically on the Y axis. The locating pins are of GB / T120.1-2000 10x30 specifications with a diameter of 10 mm and a height of 30 mm. Considering thermal deformation, the pin hole 9 in the lower part 5 adopts a circular locating pin hole with a diameter of φ10 mm and a depth of 10 mm, and the pin hole 9 in the upper part 4 adopts a waist-shaped locating pin hole with a width of 10 mm, a length of 15 mm, and a depth of 22 mm.

[0048] like Figure 1 , 2 As shown in 4, the upper and lower parts are radially positioned by a stepped fit, and the length of the stepped fit surface is 5mm. This not only improves the positioning effect, but also facilitates disassembly and assembly.

[0049] The roughness of the parting surface 3 of the upper and lower parts is 1.6, and the maximum outer circle side wall is left with 1mm processing allowance. After the two parts are fully positioned and tightened, the maximum outer diameter of the side wall is processed as a whole to fully ensure the dimensional accuracy and matching quality after the split lower mold is assembled.

[0050] Example 4

[0051] In Example 4, a 20-inch wheel mold is selected. Figure 6 As shown in the figure, it includes an upper mold 13, a side mold 14 and a lower mold 1, and the upper mold 13, the side mold 14 and the lower mold 1 form a casting cavity for the wheel. The lower mold 1 adopts the split structure lower mold in the above embodiment 1, and the parting surface 3 of the lower mold is set at the position where the overall thickness of the lower mold 1 changes sharply. The thickness of the split lower mold B is 50mm. Figure 1 Schematic form, to ensure the uniformity of the thickness of the lower mold casting cavity body to the greatest extent.

[0052] Two heat-insulating grooves 6 with a depth of 2 mm and a width of 20 mm are processed on the horizontal parting surface where the lower split body 5 is located. The edges of the two heat-insulating grooves 6 are 5 mm to the left and right of the lower mold side wall.

[0053] like Figure 2 , 3 As shown in , the threaded hole corresponding to the M16 high-strength fastening bolt 8 (GB / 70M16x35) connecting and fastening the upper part 4 and the lower part 5 is a flat-head threaded hole 7. The upper part 4 and the lower part 5 of the lower mold 1 are connected and fastened with 8 evenly distributed M16 high-strength fastening bolts 8. Generally, the bottom of the flat-head threaded hole 7 is ≥6mm away from the mold cavity, and the thread engagement length is ≥16mm. The M16 threaded hole is 8mm away from the mold cavity, and the thread engagement length is 18mm.

[0054] like Figure 3 and5 As shown in the figure, two locating pins 10 are used to locate the upper part 4 and the lower part 5 to prevent the circumferential rotation between the upper and lower parts of the lower mold 1. The two locating pins 10 are symmetrical and distributed 20 degrees symmetrically about the Y axis. The locating pins 10 are of GB / T120.1-2000 10x30 specifications with a diameter of 10 mm and a height of 30 mm. Considering thermal deformation, the pin hole 9 in the lower part 5 adopts a circular locating pin hole with a diameter of φ10 mm and a depth of 10 mm, and the pin hole 9 in the upper part 4 adopts a waist-shaped locating pin hole with a width of 10 mm, a length of 15 mm, and a depth of 22 mm.

[0055] like Figure 1 , 2 4, the upper and lower parts of the lower mold 1 are radially positioned by a stepped fit, and the length of the stepped fit surface is 5 mm. This improves the positioning effect and is also convenient for disassembly and assembly.

[0056] The roughness of the parting surface 3 of the upper and lower parts is 1.6, and the maximum outer circle side wall is left with 1mm processing allowance. After the two parts are fully positioned and tightened, the maximum outer diameter of the side wall is processed as a whole to fully ensure the dimensional accuracy and matching quality after the split lower mold is assembled.

[0057] Embodiments 3-4 were analyzed, and hot casting simulation analysis was performed using simulation software on the one-piece lower mold and the lower molds with upper and lower split structures designed according to the above two schemes in Embodiments 3-4. The results showed that compared with the one-piece lower mold, in the hot state, the thermal deformation of the upper and lower split structure lower mold in Embodiment 3 was reduced by 85%, and the thermal deformation of the upper and lower split structure lower mold in Embodiment 4 was reduced by 88.9%.

[0058] According to the mold design and processing in Examples 3-4, low-pressure casting verification of 2,000 wheel hubs was carried out respectively. The results showed that compared with before the improvement, the proportion of wheel front shape and size deviation in Example 3 was reduced by 94.2%, and the proportion of wheel front shape and size deviation in Example 4 was reduced by 96.7%, which completely solved this industry problem, greatly reduced the thermal deformation of the lower mold, and improved the casting accuracy, machining accuracy and mold life of the wheel front.

[0059] The embodiments of the present application are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. At the same time, for general technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. Split structure lower mold, characterized by: A cavity is provided at the bottom of the lower mold, and a horizontal parting surface is provided between the outer edge of the cavity and the outer edge of the lower mold along the top of the cavity, and the parting surface divides the lower mold into an upper part and a lower part, and the lower part is in a circular ring shape; The upper part and the lower part are matched in a stepped manner, and the step platform is arranged on the inner side of the parting surface; A circle of bosses is arranged on the inner side of the top surface of the lower body, and a depression is arranged correspondingly on the lower end surface of the upper body, and the bosses and the depression form a stepped fit; More than one circle of deep holes and shallow holes are provided on the bottom surface of the upper split body; the number of the deep holes and shallow holes in each circle is equal, and the deep holes and shallow holes are arranged at intervals.

2. According to the split structure lower mold in claim 1, it is characterized in that: At the parting surface, a heat insulation groove is provided on the upper part or the lower part.

3. According to the split structure lower mold in claim 2, it is characterized in that: The heat insulation groove is in an annular shape as a whole and surrounds the cavity.

4. According to the split structure lower mold in claim 1, it is characterized in that: The upper part and the lower part are provided with flat-head threaded holes correspondingly, and the flat-head threaded holes cooperate with bolts to connect and fix the upper part and the lower part.

5. According to the split structure lower mold in claim 1, it is characterized in that: The upper body and the lower body are provided with pin holes correspondingly, and the pin holes cooperate with the positioning pins to position the circumference of the upper body and the lower body, thereby preventing the upper body and the lower body from rotating circumferentially.

6. The split structure lower mold according to claim 5, characterized in that: One of the locating pin holes of the upper split body and the locating pin holes of the lower split body is waist-shaped, and the other is circular.

7. A wheel low-pressure casting mold, comprising an upper mold, a side mold and a lower mold, wherein the upper mold, the side mold and the lower mold form a casting cavity of the wheel, characterized in that: The lower mold is a split structure lower mold as described in any one of claims 1-6.

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