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CN-121669863-B - Integrated salt core forming process for casting aluminum alloy structural part by using automobile calipers

CN121669863BCN 121669863 BCN121669863 BCN 121669863BCN-121669863-B

Abstract

The invention relates to the technical field of casting aluminum alloy, and discloses an integrated salt core forming process of an automobile caliper casting aluminum alloy structural part, which comprises the steps of obtaining aluminum alloy liquid; the method comprises the steps of integrally preparing a full-salt-based core body by using salt raw materials, preheating the full-salt-based core body, an upper die assembly and a lower die assembly, gradually increasing the heating temperature of the full-salt-based core body, placing the full-salt-based core body into a casting cavity for casting aluminum alloy liquid, taking out a middle wedge block and a fixed block after casting molding, separating a die, taking out a casting, cooling, trimming, cleaning the casting, and performing heat treatment. The invention reduces the complexity of the assembly process by preparing the integrated full-salt-based core body, improves the forming precision of the core body structure, improves the structural strength of the full-salt-based core body by gradually heating the full-salt-based core body, and can quickly and nondestructively take out castings by sequentially removing the middle wedge block, the fixed block and the upper cover plate, thereby avoiding damaging the die, realizing the repeated use of the upper die assembly and reducing the complexity and the cost of the forming process.

Inventors

  • Chu Zhaohuan
  • FANG SONG

Assignees

  • 安庆雅德帝伯活塞有限公司

Dates

Publication Date
20260505
Application Date
20260211

Claims (9)

  1. 1. An integrated salt core forming process for casting an aluminum alloy structural member by using an automobile caliper is characterized by comprising the following steps of: s1, heating an aluminum alloy raw material to obtain an aluminum alloy liquid; S2, integrally preparing a full-salt-based core body (2) by using salt raw materials, wherein the full-salt-based core body (2) comprises a lower cylinder body (21) and oil channels (23) arranged at two ends of the lower cylinder body (21), two ends of each oil channel (23) are respectively intersected with two ends of the lower cylinder body (21), the full-salt-based core body (2), an upper die assembly (1) and a lower die assembly (3) are preheated, heating temperature is gradually increased and heat preservation treatment is carried out in the heating process of the full-salt-based core body (2), the heating temperature is in the range of 350-550 ℃, the heating time is 85-100 min, and the heat preservation time is 10-15 min, and the step-by-step heating temperature increase comprises the steps of setting three heating temperatures which are gradually increased; S3, placing the preheated full-salt-based core body (2) into a casting cavity formed by combining an upper die assembly (1) and a lower die assembly (3), and pouring the aluminum alloy liquid from the lower die assembly (3), wherein the upper die assembly (1) comprises an upper fixing piece (11), and the upper fixing piece (11) comprises a middle wedge block (111) and a fixing block (112) which can be mutually separated; s4, sequentially taking out the middle wedge block (111) and the fixed block (112) after casting molding, and separating the upper die assembly (1) from the lower die assembly (3) so as to take out the casting for cooling; And S5, trimming and cleaning the cooled casting, and performing heat treatment on the casting to finish the production of the casting.
  2. 2. The integrated salt core forming process according to claim 1, wherein in the second step, the full salt base core (2) further comprises a plurality of piston ends (22) respectively arranged at two sides of the lower cylinder (21), and the piston ends (22) intersect with two ends of the oil duct (23) to form an annular oil path.
  3. 3. The integrated salt core forming process according to claim 2, wherein the oil passage (23) includes a hypotenuse section (231) intersecting the piston end (22), an arc section (232) connected to the hypotenuse section (231), a bend section (233) connected to the arc section (232), the bend section (233) being of a U-shaped structure.
  4. 4. A one-piece salt core forming process according to claim 3, wherein the piston end (22) comprises a middle column (221) communicated with the lower cylinder body (21), an annular rib (222) is formed at one end of the middle column (221) close to the lower cylinder body (21), a connecting rib (223) is formed at one end of the middle column (221) far away from the lower cylinder body (21), the connecting rib (223) is communicated with two ends of the bevel edge section (231), and the connecting ribs (223) at the same side of the lower cylinder body (21) are all communicated through a connecting column (224) to form the annular oil path communicated with the oil duct (23), the connecting rib (223) and the connecting column (224).
  5. 5. The integrated salt core forming process according to claim 4, wherein a plurality of semicircular holes are formed at the bottom of the fixing block (112), the bottom side surface of the middle wedge block (111) is the bottom end surface of the semicircular hole, so as to form a semicircular groove (114), and the annular ribs (222) are embedded with the semicircular groove (114) one by one, so as to form a positioning structure.
  6. 6. The integrated salt core forming process according to claim 1, wherein in the third step, the upper die assembly (1) further comprises an upper cover plate (12), the upper cover plate (12) forms a through hole to be embedded into the fixed blocks (112), the middle wedge blocks (111) are embedded between the fixed blocks (112) through a concave-convex structure, convex edges (113) are formed on one side of the fixed blocks (112) far away from the middle wedge blocks (111) so as to be connected with the upper cover plate (12), and bolt connection structures are formed on the top of the middle wedge blocks (111) and the tops of the fixed blocks (112) on two sides; when the fixing block (112) and the middle wedge block (111) are fixed in the through hole of the upper cover plate (12), the bottom of the upper die assembly (1) forms the upper half part of the casting cavity, and the top of the lower die assembly (3) forms the lower half part of the casting cavity.
  7. 7. The integrated salt core forming process according to claim 6, wherein in step three, the lower die assembly (3) comprises: a lower bottom plate (31) connected with the upper cover plate (12), wherein the lower bottom plate (31) and the upper cover plate (12) are connected to form the casting cavity so as to contain the aluminum alloy liquid; And a pouring channel (32) formed on the top surface of the lower plate (31), wherein the pouring channel (32) forms a pouring opening (33) on the side surface of the lower plate (31).
  8. 8. The integrated salt core forming process according to claim 1, wherein in the fourth step, the cooling range of the casting is 320 ℃ to 420 ℃ and the cooling time range is 200s to 420s.
  9. 9. The integrated salt core forming process according to claim 1, wherein in the fifth step, the heat treatment includes: Carrying out solution treatment on the casting, wherein the heating temperature is 530-550 ℃, and the heat preservation is carried out for 5-8.5 hours; controlling the solid solution transfer time to be less than or equal to 30 seconds; and (3) aging the casting at the aging temperature of 170-200 ℃ for 3-6 hours.

Description

Integrated salt core forming process for casting aluminum alloy structural part by using automobile calipers Technical Field The invention relates to the technical field of casting aluminum alloy, in particular to an integrated salt core forming process for an automobile caliper casting aluminum alloy structural part. Background As a key component in a vehicle brake system, the structural complexity and performance requirements of the automobile calipers are increasingly improved along with industry development. The fixed car calliper inner structure is accurate, is equipped with the cylinder body space that is used for the piston motion generally and connects the built-in oil circuit of both sides cylinder body. These internal passages need to be integrally formed during the casting process to ensure smooth transfer of brake fluid under pressure, thereby avoiding leakage and ensuring rapidity of braking response. Currently, the production of automobile calipers mostly adopts a gravity casting process. In the conventional technology, the forming of the internal oil path and the cylinder space mainly depends on a sand core, for example, the sand core is manufactured by precoated sand to preset the internal cavity of the caliper. However, the sand core forming process has the obvious defects of poor surface quality, large roughness of the inner surface of the oil duct formed by casting and increased flow resistance of liquid due to larger granularity and limited compactness of the sand core material. To solve the above problems, the industry has begun to explore solutions that use salt cores instead of sand cores. As disclosed in CN117680618a, a process for forming salt core of oil passage of caliper is disclosed, which uses the characteristics of small gas generation and small granularity of salt core material to reduce the roughness of inner wall surface of oil passage and improve the internal quality of casting. Although the application of the salt core improves the surface precision and the cleaning efficiency, the casting of the high-performance integrated caliper still faces the challenges that the structural integration level is low, the existing salt core structure often needs a plurality of splicing assemblies, the assembly complexity of the core structure is increased, the high-precision position requirement is difficult to ensure, the assembly error is easy to generate, and the positioning and demoulding contradiction is that the stable positioning of the large-size integrated salt core in a casting mould becomes extremely difficult along with the complicated and integrated development of an internal oil way of the caliper. In the casting process, the aluminum liquid can generate scouring and buoyancy force on the salt cores with complex structures, the traditional die structure often causes difficulty in die taking after casting when fixing the salt cores, and the forced die taking is extremely easy to cause physical damage to precise integrated castings, so that the complexity and the production cost of a forming process are increased. Therefore, how to design a caliper casting forming process which can realize high-precision integrated forming, ensure stable positioning and realize nondestructive demolding is a technical problem to be solved in the current automobile brake part manufacturing field. Disclosure of Invention The invention provides an integrated salt core forming process for casting an aluminum alloy structural member of an automobile caliper, which aims to solve the problem of how to design a caliper casting forming process capable of realizing high-precision integrated forming, ensuring stable positioning and realizing nondestructive demolding, and has the following specific technical scheme: An integrated salt core forming process for casting an aluminum alloy structural member by using an automobile caliper comprises the steps of heating an aluminum alloy raw material to obtain an aluminum alloy liquid; the method comprises the steps of integrally preparing a full-salt-based core body by using salt raw materials, wherein the full-salt-based core body comprises a lower cylinder body and oil ducts arranged at two ends of the lower cylinder body, two ends of each oil duct are intersected with two ends of the lower cylinder body respectively, preheating the full-salt-based core body, an upper die assembly and a lower die assembly, heating the full-salt-based core body in a step-by-step heating temperature increasing mode and heat preservation treatment, the heating temperature ranges from 350 ℃ to 550 ℃, the heating time ranges from 85min to 100min, the heat preservation time ranges from 10min to 15min, the step-by-step heating temperature increasing mode comprises the steps of setting three step-by-step heating temperatures, setting the heating time according to the increasing range of the heating temperature to gradually reduce the heating rate, placing the preheated full-salt-bas