A 360-degree conical gyratory thin-wall structure casting mouth roundness correction tool and correction method

Abstract

This invention discloses a fixture and method for correcting the roundness of the opening of a 360° conical thin-walled casting, belonging to the field of casting technology. The correction fixture includes a lower mold base, a bottom pad, a limiting block, a correction pad, a first correction block, and a second correction block. The inner wall of the lower mold base cavity is reserved with anti-deformation compensation to offset elastic rebound after correction, including 0.5° taper compensation and 0.25mm radial dimension compensation. During correction, the casting is placed in the cavity of the lower mold base. The conical surface of the first correction block converts the axial pressure borne by the second correction block and the correction pad into a uniform radial tightening force, forcing the opening of the casting to shrink inward and fit into the cavity. After pressure holding and aging, it is removed. This method solves the problems of low efficiency, poor accuracy, and easy secondary deformation caused by traditional manual correction, achieving efficient, accurate, and consistent correction of the roundness of the opening of conical thin-walled castings.

Description

Technical Field

[0001] This invention belongs to the field of casting technology, specifically relating to a special tooling for correcting the roundness of the opening of a 360° conical rotating thin-walled structure casting and a correction method using the tooling. Background Technology

[0002] Thin-walled castings with a 360° conical shape of rotation, such as certain engine casings and housing components, are prone to deformation during casting solidification and cooling due to their unique geometry and thin walls. This deformation is often caused by uneven cooling rates in different areas, inconsistent solidification shrinkage, and residual stress release. The opening (usually the larger end) is particularly susceptible to defects such as excessive ellipticity and outward expansion of the diameter. These deformations can severely affect the assembly accuracy and sealing performance between the casting and adjacent components, and may even lead to product scrap.

[0003] Currently, the industry primarily employs traditional mechanical straightening methods for correcting the roundness of the casting openings. The most common method is manual hammering, where operators, relying on experience, use tools like copper or rubber hammers to tap the deformed area, attempting to restore it to its theoretical shape. Additionally, there are simpler clamping methods, using simple ring clamps or modules to mechanically constrain the casting opening before applying external force for straightening. However, these traditional methods have several inherent drawbacks: First, they are inefficient, heavily reliant on the operator's experience and skill level, resulting in inconsistent quality. Second, straightening accuracy is difficult to guarantee, leading to poor roundness consistency and failing to meet high-precision assembly requirements. Third, manual hammering or simple constraints can easily generate excessive concentrated stress in localized areas of the casting, potentially causing microcracks or secondary deformation, and even new deformations during subsequent use due to stress release. Finally, for mass production, traditional methods are slow, costly, and difficult to standardize.

[0004] Therefore, there is an urgent need in this field to develop a special tooling and method that can efficiently, stably, and accurately correct the roundness of the opening of a 360° conical rotating thin-walled casting, in order to overcome the shortcomings of existing technologies and meet the needs of modern high-precision manufacturing. Summary of the Invention

[0005] The purpose of this invention is to overcome the aforementioned deficiencies of the prior art and provide a tooling and method for correcting the roundness of the opening of a 360° conical rotating thin-walled structure casting. This tooling, through a unique anti-deformation compensation cavity design and a multi-component collaborative force-applying mechanism, can achieve uniform and controllable radial tightening correction of the casting opening, effectively counteracting springback and ensuring the roundness accuracy and consistency of batch products after correction.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A tooling for correcting the roundness of the opening of a 360° conical rotating thin-walled structure casting is characterized by comprising a lower mold base, a bottom pad, a limiting block, a correcting pad, a first correcting block, and a second correcting block, wherein: the lower mold base is a rigid base, the top of the lower mold base is provided with a conical cavity for accommodating the casting, the inner wall of the cavity is provided with an anti-deformation compensation structure, and the inner wall of the cavity is also provided with a limiting boss for circumferentially limiting the casting; the bottom pad is a ring structure and is disposed below the lower mold base; the first correcting block is a frustum structure, the lower conical surface of the frustum structure is used to fit against the conical surface of the casting; the second correcting block is a columnar structure, the top of the second correcting block contacts a press, the bottom of the second correcting block is installed in the central hole of the first correcting block, and the columnar structure is used to apply axial pressure to the base of the casting; The straightening pad is a hollow cylindrical structure, concentrically fitted outside the second straightening block, and placed on the upper surface of the first straightening block, with its top contacting the press. When the press applies pressure, the axial pressure of the press acts simultaneously on the straightening pad and the second straightening block to drive the first straightening block to squeeze the casting. The inner wall of the lower die applies a uniform radial tightening force to the opening of the casting, causing the casting to shrink radially inward to complete the straightening work. The limiting block is a circular ring structure, located at the bottom center of the lower die. The limiting block is used to contact the casting base during the pressure holding stage to restrict its axial movement.

[0007] Preferably, the anti-deformation compensation structure includes: the taper of the cavity is 0.3°-0.7° smaller than the inner cone surface of the casting target, and / or the surface of the cavity is offset in the radial direction by 0.15mm-0.35mm from the inner surface of the casting target.

[0008] Preferably, a limiting groove is provided between the limiting bosses, and a supporting ridge is provided in the middle of the limiting groove.

[0009] Preferably, the outer wall of the casting is provided with multiple pairs of external toothed blades at equal intervals, the inner wall of the casting is provided with multiple pairs of internal toothed blades at equal intervals, and the bottom plane of the casting is provided with multiple arc-shaped curved blades, wherein: the outer contour of the pair of external toothed blades is consistent with the shape of the limiting groove; the multiple arc-shaped curved blades extend in an arc shape along the circumference of the inner bottom ring of the casting, and the multiple arc-shaped curved blades are arranged in a spiral array to form a central vortex structure, which is used to guide the airflow to form a vortex in the central region.

[0010] Preferably, it also includes limiting posts, and a plurality of the limiting posts are symmetrically arranged on the limiting block.

[0011] A correction method using the above-mentioned mouth roundness correction fixture includes the following steps: S1. Casting clamping: The casting to be corrected is placed in the cavity of the lower mold base and circumferentially positioned by the limiting boss; S2, Pressure Correction: Place the correction pad, the first correction block, and the second correction block on the casting; start the press to press down, and drive the first correction block through the second correction block and the correction pad, so that the first correction block applies a radial tightening force to the opening of the casting, so that the opening of the casting fits against the inner wall of the cavity. S3, Pressure Holding Time: Maintain pressure for a period of time; S4. Unloading and Inspection: Remove the pressure, take out the casting, and check the roundness of the opening.

[0012] Preferably, in step S2, the first correction block is adjusted so that its lower conical surface fits against the conical inclined surface of the casting, and the lower end surface of the second correction block contacts the upper surface of the first correction block.

[0013] Preferably, the pressure holding time in step S3 is 3-5 minutes.

[0014] Preferably, if the roundness of the casting opening does not meet the requirements after step S4, steps S2 and S3 are repeated for further correction.

[0015] The beneficial effects of this invention are as follows: 1) Precise compensation and high precision: The tooling cavity innovatively presets a dual composite anti-deformation compensation amount of 0.5° taper and 0.25mm radial dimension, which scientifically predicts and offsets the elastic rebound of the casting after straightening and unloading, ensuring that the roundness of the mouth after straightening can stably and accurately meet the design tolerance requirements.

[0016] 2) Uniform force distribution and stable quality: Through the conical transmission of the first correction block and the coordinated downward pressure of the second correction block and the correction pad, the axial pressure of the press is converted into a uniform and synchronous radial tightening force on the casting opening. Combined with the circumferentially distributed limiting force of the cavity, local stress concentration is avoided, effectively preventing new irregular deformations or microscopic damage during the correction process, ensuring the stability of the correction quality and the consistency of batch products.

[0017] 3) Structural optimization and cost savings: A modular design combining a first correction block, a second correction block, and a correction pad replaces a potentially large and complex integrated module. This design enables multi-position and multi-directional coordinated force application while reducing the volume and weight of individual components, lowering the processing difficulty and material costs of tooling, and achieving the goal of realizing complex functions with a simple structure.

[0018] 4) Convenient operation and improved efficiency: The tooling structure is simple and reasonable, and the clamping, centering, and unloading operations are convenient and quick, reducing the reliance on operator skills. The entire straightening process is mechanized and standardized, which significantly improves the efficiency of straightening operations and eliminates the uncertainty and errors caused by manual operation. Attached Figure Description

[0019] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 is a schematic diagram of the overall structure of the present invention.

[0021] Figure 2 is a schematic diagram of the component installation of the present invention.

[0022] Figure 3 is a schematic diagram of the lower mold base structure of the present invention.

[0023] Figure 4 is a schematic diagram of the casting structure of the present invention.

[0024] Figure 5 is a schematic diagram of the installation position of the limiting post of the present invention.

[0025] In the diagram: 1. Lower mold base; 101. Limiting boss; 102. Limiting groove; 103. Support ridge; 2. Bottom pad block; 3. Limiting block; 4. Correcting pad block; 5. First correction block; 6. Second correction block; 7. Casting; 701. External toothed plate pair; 702. Internal toothed plate; 703. Arc-shaped curved blade; 8. Limiting post. Detailed Implementation

[0026] In the description of this invention, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0027] The present invention will now be described in detail with reference to the accompanying drawings.

[0028] As shown in Figures 1 to 5, this embodiment provides a tooling for correcting the roundness of the opening of a 360° conical rotating thin-walled structure casting, which mainly includes a lower mold base 1, a bottom pad 2, a limiting block 3, a correction pad 4, a first correction block 5, and a second correction block 6.

[0029] In the diagram, the lower mold base 1 is the foundation and core positioning component of the entire tooling. It is made of high-strength steel and is a rigid, disc-shaped base. Its top is machined with a tapered cavity that matches the outer contour of the casting 7 to be straightened, used to accommodate the casting. The inner wall of this cavity is not machined according to the theoretical final dimensions of the casting, but rather with a pre-reserved anti-deformation compensation amount: specifically, the taper of the cavity is 0.5° smaller than the target inner tapered surface of the casting, and its surface is offset radially inward by 0.25mm. This composite compensation amount is determined based on the material's mechanical properties and numerous process tests, used to precisely counteract the elastic rebound of the casting after the straightening pressure is released, ensuring that the final dimensions meet the standards. The inner wall of the cavity is also machined with multiple circumferentially distributed limiting bosses. When the casting is placed in, these bosses contact the outer wall of the casting, restricting its horizontal movement and achieving precise positioning. The bottom of the lower mold base 1 is machined with threaded holes, allowing it to be securely mounted on the press's worktable using bolts.

[0030] In the figure, the bottom pad 2 is placed below the lower mold base 1 to adjust the overall height of the tooling and ensure that the casting has enough axial movement space when the press is pressed down, so that radial shrinkage can occur smoothly.

[0031] In the diagram, the limiting block 3 plays a role in the later stage of the straightening process, namely the pressure holding stage. When the press presses down to the predetermined position, the upper surface of the limiting block 3 contacts the lower surface of the base of the casting 7, preventing the casting from axially moving due to stress adjustment during the pressure holding period.

[0032] It should be noted that the first correction block 5 is a key force transmission and conversion component. Its main body is a frustum-shaped cone, with a conical lower surface designed to fit tightly against the large conical area of ​​the casting 7 requiring correction. Its upper surface is flat. The second correction block 6 is the main direct force-applying component, shaped like a cylindrical rod. Its lower end face presses directly against the central area of ​​the casting 7's base, applying axial pressure. Its cylindrical section is adjacent to the correction pad 4. The correction pad 4 is placed beside the second correction block 6, with its upper surface essentially at the same level as the upper end face of the second correction block 6. When the press head of the press descends, it acts simultaneously on both the second correction block 6 and the correction pad 4.

[0033] It should be noted that the outer wall of the casting 7 is provided with multiple pairs of external toothed blades 701 at equal intervals, the inner wall of the casting 7 is provided with multiple pairs of internal toothed blades 702 at equal intervals, and the bottom plane of the casting 7 is provided with multiple arc-shaped curved blades 703. The outer contour of the pair of external toothed blades 701 is consistent with the shape of the limiting groove 102, and the pair of external toothed blades 701 can be snapped onto the supporting ridge 103. The multiple arc-shaped curved blades 703 extend in an arc shape along the circumference of the bottom inner ring of the casting 7, and the multiple arc-shaped curved blades 703 are arranged in a spiral array to form a central vortex structure, which is used to guide the airflow to form a vortex in the central region.

[0034] In actual operation, the correction process is as follows: First, the casting is clamped (S1). The casting 7, whose roundness at the opening is out of tolerance due to deformation, is placed into the cavity of the lower mold base 1 with its small end facing down. Automatic centering is achieved by the limiting boss in the cavity, ensuring that the casting and the tooling are coaxial. Then, pressure correction (S2) is performed. The correction pad 4, the first correction block 5, and the second correction block 6 are placed sequentially in the center area above the casting 7. The position of the first correction block 5 is adjusted so that its lower conical surface is completely in contact with the large conical surface of the casting 7. The second correction block 6 is placed in the center of the casting base, with its lower end face in contact with the upper surface of the first correction block 5. The press is started, and the pressure head slowly presses down, acting on the second correction block 6 and the correction pad 4. The second correction block 6 directly transmits axial pressure to the center of the casting base. At the same time, the downward pressure of the correction pad 4 pushes the first correction block 5. Since the lower surface of the first correction block 5 is conical and fits against the conical surface of the casting, when it is subjected to a downward force, it generates an inward horizontal component force (radial force). This force drives the conical wall of the casting to contract inward. Under the action of the radial contraction force, the opening of the casting gradually fits against the inner wall of the cavity of the lower mold base 1, which has anti-deformation compensation. Next, pressure holding aging S3 is performed. When the pressure reaches the set value and the opening of the casting basically fits against the cavity, the pressure is kept constant for 3-5 minutes. This process allows the stress inside the casting material to be fully redistributed and relaxed, stabilizing the deformation effect and minimizing springback after unloading. Finally, part removal inspection S4 is performed. The pressure is slowly released, and the second correction block 6, the first correction block 5, and the correction pad block 4 are removed in sequence. The corrected casting 7 is then removed from the lower mold base 1. The roundness of its opening is checked using a precision measuring instrument. If the result meets the requirements, the correction is complete; if not, steps S2-S3 can be repeated for micro-correction, which usually takes 1-2 times to achieve the required accuracy.

[0035] It should be further clarified that a 100T to 200T press is used until the casting has no axial displacement, and the correction is performed at room temperature. This invention, through the aforementioned tooling structure and method, achieves efficient, high-precision, and consistent correction of the roundness of the opening of a 360° conical rotating thin-walled casting.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A tooling for correcting the roundness of the opening of a 360° conical rotating thin-walled structural casting, characterized in that, It includes a lower mold base (1), a bottom pad (2), a limiting block (3), a straightening pad (4), a first straightening block (5), and a second straightening block (6), wherein: The lower mold base (1) is a rigid base. The top of the lower mold base (1) is provided with a conical cavity for accommodating the casting (7). The inner wall of the cavity is provided with an anti-deformation compensation structure. The inner wall of the cavity is also provided with a limiting boss (101) for circumferentially limiting the casting (7). The bottom pad (2) has a circular ring structure and is located below the lower mold base (1); The first correction block (5) is a frustum structure, and the lower cone surface of the frustum structure is used to fit against the cone surface of the casting (7); The second correction block (6) is a columnar structure. The top of the second correction block (6) contacts the press, and the bottom of the second correction block (6) is installed in the center hole of the first correction block (5). The columnar structure is used to apply axial pressure to the chassis of the casting (7). The correction pad (4) is a hollow cylindrical structure. The correction pad (4) is concentrically fitted outside the second correction block (6). The correction pad (4) is placed on the upper surface of the first correction block (5). The top of the correction pad (4) contacts the press. When the press applies pressure, the axial pressure of the press acts on the straightening pad (4) and the second straightening block (6) at the same time, so as to drive the first straightening block (5) to squeeze the casting (7). The inner wall of the lower die base (1) applies a uniform radial tightening force to the mouth of the casting, and the casting (7) shrinks inward along the radial direction to complete the straightening work. The limiting block (3) is a circular ring structure. The limiting block (3) is located at the bottom center of the lower mold base (1). The limiting block (3) is used to contact the base of the casting (7) during the pressure holding stage to limit its axial movement.

2. The mouth roundness correction fixture according to claim 1, characterized in that, The anti-deformation compensation structure includes: the taper of the cavity is 0.3°-0.7° smaller than the inner cone surface of the casting (7), and / or the surface of the cavity is offset in the radial direction by 0.15mm-0.35mm from the inner surface of the casting (7).

3. The mouth roundness correction fixture according to claim 2, characterized in that, A limiting groove (102) is provided between the limiting bosses (101), and a supporting ridge (103) is provided in the middle of the limiting groove (102).

4. The mouth roundness correction fixture according to claim 3, characterized in that, The outer wall of the casting (7) is provided with multiple pairs of external toothed blades (701) at equal intervals, the inner wall of the casting (7) is provided with multiple pairs of internal toothed blades (702) at equal intervals, and the bottom plane of the casting (7) is provided with multiple arc-shaped curved blades (703), wherein: The outer contour of the outer toothed plate pair (701) is consistent with the shape of the limiting groove (102); Multiple curved blades (703) extend in an arc shape along the circumference of the bottom inner ring of the casting (7), and multiple curved blades (703) are arranged in a spiral array to form a central vortex structure, which is used to guide the airflow to form a vortex in the central region.

5. The mouth roundness correction fixture according to claim 4, characterized in that, It also includes limiting posts (8), and multiple limiting posts (8) are symmetrically arranged on the limiting block (3).

6. A correction method using the mouth roundness correction fixture as described in any one of claims 1-5, characterized in that, Includes the following steps: S1. Casting clamping: Place the casting (7) to be corrected in the cavity of the lower mold base (1) and perform circumferential positioning through the limiting boss (101); S2, Pressure Correction: Place the correction pad (4), the first correction block (5) and the second correction block (6) on the casting (7); start the press to press down, and drive the first correction block (5) through the second correction block (6) and the correction pad (4), so that the first correction block (5) applies a radial tightening force to the opening of the casting (7), so that the opening of the casting (7) fits against the inner wall of the cavity; S3, Pressure Holding Time: Maintain pressure for a period of time; S4. Unloading and inspection: Remove the pressure, take out the casting (7) and check the roundness of the opening.

7. The correction method according to claim 6, characterized in that, In step S2, the first correction block (5) is adjusted so that its lower conical surface fits against the conical inclined surface of the casting (7), and the lower end face of the second correction block (6) contacts the upper surface of the first correction block (5).

8. The correction method according to claim 7, characterized in that, The pressure holding time in step S3 is 3-5 minutes.

9. The correction method according to claim 7, characterized in that, If the roundness of the mouth of the casting (7) does not meet the requirements after step S4, then repeat steps S2 and S3 for correction.

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