Metal mold for casting large-bore cylinder liner and molding apparatus and molding method

Abstract

The application provides a metal mold for casting a large-bore cylinder liner, comprising a lifting part and a liner profile part, a cover plate upper core head part between the lifting part and the upper end of the liner profile part, and a lower core head part at the lower end of the liner profile part; each part is a hollow cylindrical structure, and the four parts are coaxially installed in sequence from top to bottom; a pneumatic vibrator is installed at the position close to the upper and lower ends in the hollow structure of the liner profile part. Meanwhile, a molding device and a molding method based on the metal mold are provided. The upper core head, the lower core head and the liner profile of the cylinder liner are all in the lower box, the dimensional accuracy is guaranteed by the mold, the lower mold is one-time molding and forming, the dimensional accuracy of the casting is high, the machining allowance of the outer circle and the inner hole can be reduced by about 20%, and the lower mold has no multiple parting surfaces, so that the box matching is convenient and the risk of fire is small.

Description

Technical Field

[0001] This invention relates to the field of casting technology, specifically to a metal mold, molding device, and molding method for casting large-diameter cylinder liners. Background Technology

[0002] Conventional large-diameter cylinder liners are typically cast using a vertical casting process. Because the cylinder liner is quite long, in addition to the upper and lower parting lines, the lower mold is usually further divided into three to four sections, each shaped separately, and then assembled sequentially during assembly. Due to the multiple sections being assembled together, ensuring the coaxiality of each section and the coaxiality of the center hole core is difficult, resulting in large cumulative errors. Therefore, the machining allowance for the outer diameter and inner diameter of the cylinder liner is relatively large. Furthermore, the numerous sections of the lower mold result in many parting surfaces, making assembly inconvenient and increasing the risk of arcing. Summary of the Invention

[0003] To address the aforementioned shortcomings in the prior art, this invention provides a metal mold, molding device, and molding method for casting large-diameter cylinder liners.

[0004] According to one aspect of the present invention, a metal mold for casting large-diameter cylinder liners is provided, comprising: a lifting part and a cylinder liner outer shape part, a core head part on a cover plate located between the upper port of the lifting part and the cylinder liner outer shape part, and a lower core head part located at the lower port of the cylinder liner outer shape part; wherein each part is a hollow cylindrical structure, and the four parts are coaxially installed from top to bottom.

[0005] A pneumatic vibrator is installed inside the hollow structure of the cylinder liner's outer part near the upper and lower ports. This vibrator is used to assist in sand molding, ensuring that the cavity size is larger than the single-sided size of the mold, which facilitates demolding after the resin sand has cured.

[0006] Preferably, the metal mold is made of ductile iron through machining.

[0007] Preferably, the surface finish of the outer surface of the metal mold is Ra3.2 or higher.

[0008] Preferably, the wall thickness of the metal mold is 30-50 mm.

[0009] Preferably, the four parts are coaxially integrally formed and installed from top to bottom.

[0010] Preferably, the lifting part has two pairs of circular holes in the diametrical direction for suspending and / or lifting the metal mold.

[0011] Preferably, the pneumatic vibrator, located near the upper port, is situated at 1 / 4 of the overall length of the metal mold.

[0012] Preferably, the cylinder liner outer shape forms three chambers from top to bottom, and the diameters of the lifting part and the three chambers decrease sequentially from top to bottom, so that the outer surface of the metal mold forms a stepped structure.

[0013] Preferably, it further includes any one or more of the following components:

[0014] - Compressed air pipe, which is connected to the pneumatic vibrator;

[0015] - A round steel bar, which is adapted to be installed with the lifting part for suspending and / or lifting the metal mold.

[0016] According to another aspect of the present invention, a molding apparatus for casting large-diameter cylinder liners is provided, comprising: a sand box and a metal mold as described above, wherein the metal mold is detachably suspended at the center inside the sand box, and a molding cavity is formed between the sand box and the metal mold.

[0017] Preferably, in the working state, the sand box is placed in the pit.

[0018] Preferably, the sand box includes multiple circular sand boxes, which are coaxially stacked and securely fastened.

[0019] According to a third aspect of the present invention, a molding method for casting large-bore cylinder liners is provided, comprising:

[0020] Provide a metal mold and a sandbox;

[0021] First, a portion of resin sand is placed inside the sand box, and then the metal mold is suspended inside the sand box.

[0022] While adding sand, pound the sand, and when the sand is added to the set height, apply vibration to the added resin sand to assist in the sand pounding and molding, ensuring that the cavity size is larger than the single side size of the mold so that the mold can be removed after the resin sand has cured;

[0023] Continue adding sand until the full height is reached. Then stop adding sand, pound it tightly, and scrape it smooth to complete the shaping process.

[0024] After the resin sand has hardened, stop applying vibration and lift the metal mold vertically upwards to complete the demolding process;

[0025] in:

[0026] The metal mold is the metal mold described in any one of the above-described embodiments of the present invention;

[0027] The application of vibration force to the placed resin sand is achieved by activating the pneumatic vibrator of the metal mold.

[0028] Preferably, the set height is 2 / 3 of the height of the sand box.

[0029] Preferably, the amplitude of the applied vibration force is 1 to 2 mm.

[0030] By adopting the above technical solution, the present invention has at least one of the following beneficial effects compared with the prior art:

[0031] The metal mold, molding device, and molding method for casting large-diameter cylinder liners provided by this invention solve the problems of conventional cylinder liners having multiple parting surfaces and large machining allowances for the outer diameter and inner hole. The upper core head, lower core head, and cylinder liner shape are all located in the lower mold, and the dimensional accuracy is guaranteed by the mold. The lower mold is formed in one step, resulting in high dimensional accuracy of the casting. The machining allowance for the outer diameter and inner hole can be reduced by about 20%. Since the lower mold has no multiple parting surfaces, it is convenient to fit the mold and has a low risk of arcing.

[0032] The present invention provides a metal mold, molding device and molding method for casting large-diameter cylinder liners. A pneumatic vibrator is installed on the metal mold to assist in sand pounding and molding, ensuring that the cavity size is 1-2 mm larger on one side than the mold size, which facilitates demolding after the resin sand has cured. Attached Figure Description

[0033] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0034] Figure 1 This is a schematic diagram of the structure of a metal mold and molding device for casting large-diameter cylinder liners according to a preferred embodiment of the present invention.

[0035] Figure 2 This is a molding method for casting large-diameter cylinder liners in a preferred embodiment of the present invention.

[0036] In the diagram, 1 is the sand box, 2 is the round steel bar, 3 is the cylinder liner metal mold, 3.1 is the lifting part, 3.2 is the core head part on the cover plate, 3.3 is the cylinder liner outer shape part, 3.4 is the lower core head part, 4 is molding sand, 5 is the pneumatic vibrator, and 6 is the compressed air pipe. Detailed Implementation

[0037] The embodiments of the present invention are described in detail below: These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

[0038] Existing methods for manufacturing large-diameter cylinder liners typically employ a vertical casting process, which suffers from the technical problem of large machining allowances on the outer diameter and inner bore of the cylinder liner. To address this issue, one embodiment of the present invention provides a metal mold for casting large-diameter cylinder liners. This metal mold achieves high dimensional accuracy for large-diameter cylinder liners and reduces machining allowances.

[0039] like Figure 1 As shown, the metal mold for casting large-diameter cylinder liners provided in this embodiment may include: a lifting part and a cylinder liner outer shape part, a core head part on a cover plate located between the upper port of the lifting part and the cylinder liner outer shape part, and a lower core head part located at the lower port of the cylinder liner outer shape part; wherein each part is a hollow cylindrical structure, and the four parts are coaxially installed from top to bottom.

[0040] A pneumatic vibrator is installed inside the hollow structure of the cylinder liner near the upper and lower ports. This pneumatic vibrator can assist in sand molding, ensuring that the cavity size is slightly larger than the single side size of the mold (about 1-2 mm), which facilitates demolding after the resin sand has cured.

[0041] In a preferred embodiment, the metal mold is made entirely of ductile iron by machining.

[0042] In a preferred embodiment, the surface finish of the metal mold is Ra3.2 or higher.

[0043] In a preferred embodiment, the wall thickness of the metal mold is 30-50 mm.

[0044] In a preferred embodiment, the four parts are coaxially integrally molded and installed sequentially from top to bottom.

[0045] In a preferred embodiment, two pairs of circular holes are provided in the diameter direction of the lifting part for suspending and / or lifting the metal mold.

[0046] In a preferred embodiment, the pneumatic vibrator, located near the upper port, is situated at 1 / 4 of the overall length of the metal mold.

[0047] In a preferred embodiment, the cylinder liner outer portion forms three chamber sections from top to bottom, and the diameters of the lifting portion and the three chamber sections decrease sequentially from top to bottom, so that the outer surface of the metal mold forms a stepped structure.

[0048] In a preferred embodiment, it further includes any one or more of the following components:

[0049] - Compressed air pipe, which is connected to the pneumatic vibrator;

[0050] - Round steel bar, which is adapted to the lifting part for suspending and / or lifting metal molds; further, the round steel bar is detachably adapted to be installed in the round hole of the lifting part.

[0051] One embodiment of the present invention provides a molding device for casting large-diameter cylinder liners.

[0052] like Figure 1 As shown, the molding device for casting large-diameter cylinder liners provided in this embodiment may include: a sand box and a metal mold provided in the above embodiment of the present invention. The metal mold is detachably suspended at the center inside the sand box, and a molding cavity is formed between the sand box and the metal mold.

[0053] In a preferred embodiment, the sand box is placed in the pit during operation.

[0054] In a preferred embodiment, the sand box includes a plurality of circular sand boxes, which are coaxially stacked and securely mounted.

[0055] One embodiment of the present invention provides a molding method for casting large-diameter cylinder liners.

[0056] like Figure 2 As shown, the molding method for casting large-diameter cylinder liners provided in this embodiment may include:

[0057] S1 provides a metal mold and a sand box;

[0058] S2, First, put a portion of resin sand into the sand box, and then suspend the metal mold inside the sand box;

[0059] S3, while adding sand, pound the sand, and when the sand is added to the set height, apply vibration force to the added resin sand to assist in the sand pounding and molding function, so as to ensure that the cavity size is slightly larger than the single side size of the mold (about 1 to 2 mm), which makes it easier to remove the mold after the resin sand has cured.

[0060] S4, continue adding sand until the full height is reached, then stop adding sand, pound it tightly and scrape it flat to complete the shaping work;

[0061] S5. After the resin sand has hardened, stop applying vibration and lift the metal mold vertically upwards to complete the demolding.

[0062] In a preferred embodiment of S3, the height is set to 2 / 3 of the height of the sand box.

[0063] In a preferred embodiment of S3, the amplitude of the applied vibration force is 1-2 mm.

[0064] In a preferred embodiment, the metal mold is the metal mold for casting large-diameter cylinder liners provided in the above embodiments of the present invention; correspondingly, the vibration force applied to the placed resin sand is achieved by activating the pneumatic vibrator of the metal mold.

[0065] The technical solutions provided by the above embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and specific application examples, but this should not be construed as limiting the scope of protection of the present invention.

[0066] like Figure 1 As shown, the metal mold used for casting large-diameter cylinder liners, namely the cylinder liner metal mold 3, is a hollow cylindrical structure. The outer circle is divided into four areas from top to bottom. The first area corresponds to the metal mold lifting part 3.1, used to lift the metal mold; the second to fourth areas correspond to the cylinder liner outer shape part 3.3, used for shaping; the area between the first and second areas corresponds to the core head part 3.2 on the cover plate, used for the core to fall into the cover plate during assembly; the lower end of the fourth area corresponds to the lower core head part 3.4, used for the core to fall into the center hole during assembly. A pneumatic vibrator 5 is fixedly installed inside the cylinder liner metal mold 3 to assist in sand pounding and shaping, ensuring that the cavity size is 1-2 mm larger than the mold size on one side, which facilitates demolding after the resin sand has cured. One pneumatic vibrator 5 is located at the upper part, about 1 / 4 of the total length of the metal mold, and the other pneumatic vibrator 5 is located at the lower end of the metal mold, near the lower core head part 3.4. Compressed air pipe 6 is connected to pneumatic vibrator 5.

[0067] In some embodiments:

[0068] The external shape of the cylinder liner metal mold is all machined to ensure a surface finish of Ra3.2 or higher. The material is ductile iron with a wall thickness of 30-50mm. After initial casting, the outer circle is fully machined, and the inner hole is partially machined (for the installation of a pneumatic vibrator). The metal mold lifting section above the metal mold has two pairs of circular holes in the diameter direction, through which the metal mold can be suspended on the sand box using round steel bars 2.

[0069] During molding, all the round sand boxes used for the cylinder liner lower mold are stacked coaxially and secured to form sand box 1, which is placed in the molding area (because it is tall after assembly, it needs to be placed in a pit). First, a portion of molding sand 4 is placed into sand box 1 (slightly higher than the lower core head 3.4). Then, a round steel bar 2 is immediately used to suspend the metal mold lifting part 3.1 inside the sand box 1. Molding sand 4 is then added while sand is pounded. When the molding sand 4 is about 2 / 3 of the height of the sand box, the compressed air pipe 6 is turned on to activate the pneumatic vibrator 5. The cylinder liner metal mold 3 immediately vibrates with an amplitude of about 1-2 mm, making the cavity size 1-2 mm larger on each side than the mold size, facilitating demolding after the resin sand has cured. After adding the molding sand 4, it is pounded and leveled to complete the molding process. After the resin sand has hardened, the pneumatic vibrator 5 is turned off, the cylinder liner metal mold 3 stops vibrating, and the cylinder liner metal mold 3 is lifted vertically upwards to complete the demolding process.

[0070] The metal mold, molding device, and molding method for casting large-diameter cylinder liners provided in the above embodiments of the present invention are all located in the lower mold, with the upper core head, lower core head, and cylinder liner outline all in the lower mold. The dimensional accuracy is guaranteed by the mold, and the lower mold is formed in one step. The casting has high dimensional accuracy, and the machining allowance for the outer circle and inner hole can be reduced by about 20%. Since the lower mold has no multiple parting surfaces, it is convenient to fit the mold and the risk of sparking is small.

[0071] Any matters not covered in the above embodiments of the present invention are well-known in the art.

[0072] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A molding method for casting large-diameter cylinder liners, characterized in that, include: Provide a metal mold and a sandbox; First, a portion of resin sand is placed inside the sand box, and then the metal mold is suspended inside the sand box. While adding sand, pound the sand, and when the sand reaches the set height, apply vibration to the added resin sand; Continue adding sand until the full height is reached. Then stop adding sand, pound it tightly, and scrape it smooth to complete the shaping process. After the resin sand has hardened, stop applying vibration and lift the metal mold vertically upwards to complete the demolding process; in: The metal mold includes: a lifting part and a cylinder liner outer shape part, a core head part on a cover plate located between the upper port of the lifting part and the cylinder liner outer shape part, and a lower core head part located at the lower port of the cylinder liner outer shape part; wherein each part is a hollow cylindrical structure, and the four parts are coaxially installed from top to bottom. A pneumatic vibrator is installed inside the hollow structure of the cylinder liner's outer part near the upper and lower ports, respectively. The pneumatic vibrator, located near the upper port, is situated at 1 / 4 of the overall length of the metal mold; The metal mold is made of ductile iron through machining. The surface finish of the outer surface of the metal mold is Ra3.2 or higher; The wall thickness of the metal mold is 30~50mm; The four parts are coaxially molded and installed as a single unit from top to bottom; The lifting section has two pairs of circular holes in its diametrical direction for suspending and / or lifting the metal mold; The cylinder liner's outer shape forms three chambers from top to bottom, and the diameters of the lifting part and the three chambers decrease sequentially from top to bottom, resulting in a stepped structure on the outer surface of the metal mold. A compressed air pipe is provided, which is connected to the pneumatic vibrator; A round steel bar is provided, which is adapted to the lifting part for suspending and / or lifting the metal mold; The application of vibration force to the placed resin sand is achieved by activating the pneumatic vibrator of the metal mold; The set height is 2 / 3 of the height of the sand box; The amplitude of the applied vibration force is 1~2mm.

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