A spinning wheel mechanism for increasing the rib filling height in spin forming of internally ribbed cylinders and its usage method

Abstract

This invention relates to a spinning wheel mechanism and its method for improving the filling height of ribbed cylindrical blanks during spinning. The method includes: installing a ribbed groove mandrel onto the spindle of a spinning machine; fixing a spherical spinning wheel to a spinning wheel frame, with one end of the spherical spinning wheel protruding from the receiving groove near the outer periphery of the spindle of the spinning machine; starting the spinning machine, causing the cylindrical blank to rotate around the spindle at a set speed under the drive of the ribbed groove mandrel, and the spherical spinning wheel moving radially and axially at a set feed ratio under the drive of the spinning wheel frame; when the spherical spinning wheel contacts the cylindrical blank, it rotates and rolls the cylindrical blank, thus filling the inner ribs. This invention uses a spherical spinning wheel, which increases the axial contact length between the spinning wheel and the cylindrical blank during spinning, and increases the material used for radial filling during the rolling process; furthermore, the greater rotational freedom of the spherical spinning wheel coordinates the deformation behavior of the material. These two factors work together to promote the filling of the material into the inner rib groove, effectively improving the filling height.

Description

Technical Field

[0001] This invention relates to the field of spinning forming technology, specifically to a spinning wheel mechanism for increasing the filling height of a ribbed cylinder during spinning forming and its usage method. Background Technology

[0002] With the rapid development of high-end equipment in aerospace and other fields, especially the development of new-generation launch vehicles, higher requirements have been placed on the integration, lightweighting, and high performance of key components. Ribbed cylindrical parts are such key components, featuring internally designed grid-like or spirally interwoven reinforcing ribs that significantly improve their stiffness and axial load-bearing capacity. Flow spinning is a superior technology for achieving high-performance integral forming of such components. However, in the flow spinning process of ribbed cylindrical parts, the axial contact length between the spinning wheel and the blank is relatively short. The axial feed of the spinning wheel forces the material to flow primarily axially, with less radial flow, often resulting in insufficient rib height and causing the formed component to fail to meet usage requirements. Furthermore, the existing spinning wheel is a single-degree-of-freedom rotating structure, only able to rotate around the axial direction. During interaction with the blank, it only generates circumferential rolling action, while the axial direction pushes the material to deform, a process primarily based on sliding friction. This deformation method increases the force required to deform the material, resulting in high forming loads and demanding equipment requirements during the forming process. Therefore, developing a new type of spinning wheel device that increases the rib filling height and reduces the forming load of internally ribbed cylindrical parts during flow spinning is of great significance for high-quality forming of internally ribbed cylindrical parts during flow spinning.

[0003] Currently, there are only a few technical methods for improving the rib height in flow spinning forming of internally ribbed cylindrical parts, both domestically and internationally. The literature (W. Lyu, M. Zhan, PF Gao, et al. Rib filling behavior in flow forming of thin-walled tube with helical grid-stiffened ribs[C]. The International Journal of Advanced Manufacturing Technology. 2022) mainly focuses on increasing the rib height by adjusting spinning process parameters such as thinning rate and feed ratio. The main problem is that the effect of process parameters in controlling rib height is limited, making it difficult to meet the current requirements for high rib and high wall thickness ratio in internally ribbed cylindrical parts. Research on improving the spinning process is also limited. Currently, the main method involves applying axial pressure (patent application number CN201910320612.1) to promote material flow towards the ribs, thereby increasing the internal rib height. However, this axial force application method requires the addition of limiting devices such as springs at the tail end of the mandrel, which increases the requirements for structural freedom and complicates the spinning forming equipment, making it difficult to meet the current demand for high freedom and high flexibility. In addition, axial force application also increases the forming load of the equipment, which goes against the development trend of cost reduction and efficiency improvement. Summary of the Invention

[0004] Based on this, the present invention provides a spinning wheel mechanism and its method for improving the filling height of internally ribbed cylindrical parts during spinning. The innovative idea is to replace the traditional double-cone rounded-corner spinning wheel with a spherical spinning wheel. During the forming process of the internally ribbed cylindrical part, the spherical spinning wheel has a longer axial contact length and more rotational degrees of freedom with the blank, which can effectively coordinate the material flow behavior and promote the filling of material into the ribs, thereby achieving a higher filling height than the traditional spinning wheel. Simultaneously, the high rotational degree of freedom of the spherical spinning wheel allows it to adaptively adjust the rotation angle during blank deformation, changing the axial sliding friction form of the traditional spinning wheel, thus effectively reducing the forming load.

[0005] To achieve the above objectives, the present invention provides a spinning wheel mechanism for increasing the filling height of a spin-formed tube with internal ribs, comprising:

[0006] Rotary support;

[0007] A spherical bearing, one end of which is connected to the wheel support, and the other end of which is provided with a receiving groove; and

[0008] A spherical wheel is rotatably housed within the receiving groove, with a portion of the spherical wheel protruding from the receiving groove. The spherical wheel has rotational degrees of freedom in the X, Y, and Z axes within the receiving groove.

[0009] The method for increasing the rib filling height of a spin-forming cylinder with internal ribs using the above-mentioned spinning wheel mechanism includes the following steps:

[0010] (1) Install the ribbed groove core mold onto the spindle of the spinning machine, and then fix the cylindrical blank with a wall thickness of t onto the ribbed groove core mold;

[0011] (2) The spherical spinning wheel is fixedly connected to the spinning wheel frame of the spinning machine through its spinning wheel support. The end of the spherical spinning wheel protrudes from the receiving groove and is close to the outer periphery of the spindle of the spinning machine. The radius r of the spherical spinning wheel and the wall thickness t of the cylindrical blank satisfy the following relationship:

[0012]

[0013] In the formula, α is the forming angle formed by the axial front end of the spherical swivel and the cylindrical blank;

[0014] (3) Start the spinning machine. The cylindrical blank rotates around the main shaft at a set speed under the drive of the core mold with rib groove. The spherical spinning wheel moves radially and axially at a set feed ratio under the drive of the spinning wheel frame. When the spherical spinning wheel contacts the cylindrical blank, it rotates and rolls the cylindrical blank to realize the filling of the inner rib.

[0015] As a further preferred technical solution of the present invention, the cylindrical blank is locked and fixed on the core mold with ribbed groove by fixing bolts.

[0016] As a further preferred technical solution of the present invention, in step (3), the spherical wheel moves radially at a speed of v=1mm / s and is fed axially at a feed ratio of f=1.5mm / s.

[0017] As a further preferred technical solution of the present invention, when the spherical roller rotates and rolls the cylindrical blank to achieve the filling of the inner ribs, the forming angle α formed by the axial front end of the spherical roller and the cylindrical blank is 20° to 30°, preferably forming angle α < 30°, so as to avoid defects such as severe diameter expansion caused by excessive forming angle.

[0018] As a further preferred technical solution of the present invention, in steps (2) and (3), at least two spherical rollers are evenly distributed around the outer periphery of the cylindrical blank so that the at least two spherical rollers work together synchronously to roll the cylindrical blank, thereby improving the processing efficiency.

[0019] The rotary wheel mechanism for increasing the filling height of the spin forming of the inner ribbed cylinder and its usage method of the present invention, by adopting the above technical solution, can achieve the following beneficial effects:

[0020] 1) The present invention uses a spherical spinning wheel, which increases the axial contact length between the spinning wheel and the blank during the spinning process, and increases the amount of material used for radial filling during the rolling process of the spinning wheel; at the same time, the more rotational freedom of the spherical spinning wheel coordinates the deformation behavior of the material. The two work together to promote the filling of the material into the inner rib groove, which can effectively increase the filling height.

[0021] 2) This invention employs a spherical spinning wheel, which possesses a certain degree of self-adaptive capability. During the forming process, the rotation angle of the spinning wheel can be adaptively adjusted according to the material's deformation resistance, thereby reducing the forming load. Taking the spinning forming of a cylindrical part with helical internal ribs as an example, compared with the spinning forming results of traditional spinning wheel devices, the spinning design method of this invention using a spherical spinning wheel significantly improves the rib height compared to the traditional method under the same spinning process parameters, while effectively reducing the forming load. Attached Figure Description

[0022] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0023] Figure 1 This is a schematic diagram of the process of using a spinning mechanism and a spinning machine to spin a cylindrical part with internal ribs using a spherical spinning wheel;

[0024] In the diagram: 1. Cylindrical blank; 2. Ribbed grooved core mold; 3. Spinner support; 4. Spherical bearing; 5. Spherical spinner; 6. Fixing bolt.

[0025] Figure 2 This is a schematic diagram illustrating the principle for selecting the radius of a spherical gyroscope.

[0026] Figure 3 It uses a spherical rotary wheel and a double-cone rounded corner transition rotary wheel to form the rib height contrast curve of the cylindrical part with spiral internal ribs.

[0027] Figure 4 Comparison curves of forming loads for forming cylindrical parts with helical internal ribs using spherical spinning wheels and double-conical rounded transition spinning wheels.

[0028] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Terms such as "upper," "lower," "left," "right," "middle," and "one" used in the preferred embodiments are merely for clarity of description and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0030] Example 1

[0031] like Figure 1 As shown in the figure, the present invention provides a rotary wheel mechanism for improving the filling height of a spin-formed tube with internal ribs, which includes a rotary wheel support 3, a joint bearing 4, and a spherical rotary wheel 5; one end of the joint bearing 4 is fixedly connected to the rotary wheel support 3, and the other end has an axial front end with a receiving groove, the spherical rotary wheel 5 is rotatably received in the receiving groove, and part of the spherical rotary wheel 5 protrudes out of the receiving groove, the spherical rotary wheel 5 has rotational freedom in the X, Y, and Z axes in the receiving groove.

[0032] The spherical spinning wheel is used in conjunction with a spinning machine. Specifically, the spherical spinning wheel is bolted to the spinning wheel frame via a spinning wheel support 3. The spinning machine is equipped with a grooved core mold 2 and a spinning wheel frame. The grooved core mold 2 and the spinning wheel frame are standard features of existing spinning machines and will not be further explained here. The cylindrical blank 1 to be processed is locked onto the grooved core mold 2 with fixing screws. During the fluid spinning process, the spherical spinning wheel 5 can rotate freely through the spherical bearing, producing a rolling effect on the cylindrical blank 1.

[0033] The method for using the aforementioned spinning mechanism to increase the rib filling height of the spin-forming tube with internal ribs is as follows:

[0034] (1) Install the core mold with ribs and grooves onto the spindle of the spinning machine, and then fix the cylindrical blank with a wall thickness of t=6mm onto the core mold with ribs and grooves by fixing bolts.

[0035] (2) The spherical spinning wheel is fixedly connected to the spinning wheel frame of the spinning machine through its spinning wheel support. One end of the spherical spinning wheel protrudes from the receiving groove and is close to the outer periphery of the spindle of the spinning machine. The forming angle of the spherical spinning wheel varies with the wall thickness of the blank and the thinning rate δ. Therefore, the present invention constrains the selection of the radius of the spherical spinning wheel according to the extreme thinning condition (δ=100%) (e.g. Figure 2 As shown in the figure (the arrow indicates the axial feed direction of the spherical roller), the radius r of the spherical roller and the wall thickness t of the cylindrical blank satisfy the following relationship:

[0036]

[0037] Through numerous experiments, it has been found that during the flow spinning process of cylindrical parts, if the forming angle α is too large, it may lead to problems such as excessive material bulging and diameter expansion in front of the spinning wheel, making the spinning process impossible. Therefore, the forming angle α is generally taken as 20-30°. In this embodiment, the cylindrical blank wall thickness t=6mm, and when maintaining α at 20-30° during spinning, a spherical spinning wheel with a diameter of Ф100mm is used.

[0038] (3) Start the spinning machine. The cylindrical blank rotates around the main shaft at a set speed of 60 r / min under the drive of the core mold with ribs. The spherical spinning wheel moves radially at a speed of v = 1 mm / s under the drive of the spinning wheel frame, and feeds axially at a feed ratio of f = 1.5 mm / s, with a thinning rate of φ = 54%. When the spherical spinning wheel contacts the cylindrical blank, it rotates and rolls the cylindrical blank to achieve the filling of internal ribs. After forming, the blank is obtained as shown in the figure. Figure 3 and 4 The data shown.

[0039] Comparative Example 1

[0040] As a control experiment for Example 1, the difference lies in the use of a rotating device with a double-conical rounded corner transition wheel instead of the spherical wheel in Example 1. This double-conical rounded corner transition wheel has a radius of 150mm, a forming angle of 22.5°, and a rounded corner radius R=10mm, while the remaining spinning parameters remain unchanged. After forming, the following is obtained: Figure 3 and 4 The data shown.

[0041] Compare Figure 3 and 4 Comparing the data from Example 1 and Comparative Example 1, it was found that the rib height after forming with a spherical rotary wheel can reach approximately 5 mm, which is 25% higher than the rib height (approximately 4 mm) of the traditional rotary wheel with a double-cone rounded transition. This is because the spherical rotary wheel increases the axial contact length between the wheel and the cylindrical blank, resulting in more material used for radial filling during the rolling process. Simultaneously, the spinning pressure during forming of the cylindrical part with internal ribs using a spherical rotary wheel is approximately 100-107 kN, which is 13% lower than the spinning pressure (115-122 kN) during the traditional rotary wheel with a double-cone rounded transition. This is because the spherical rotary wheel can adaptively adjust its rotation angle according to the material's deformation resistance during the forming process, thereby reducing the forming load. The results indicate that the spherical rotary wheel can significantly increase the rib height of the cylindrical part with internal ribs compared to the traditional double-cone rounded transition rotary wheel, while effectively reducing the forming load during the spinning process.

[0042] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and various changes or modifications can be made to these embodiments without departing from the principles and essence of the present invention. The scope of protection of the present invention is defined only by the appended claims.

Claims

1. A method for using a spinning wheel mechanism to increase the rib filling height of a spin-formed tube with internal ribs, characterized in that, The spinning wheel mechanism includes: Rotary support; A spherical bearing, one end of which is connected to the wheel support, and the other end of which is provided with a receiving groove; and A spherical wheel is rotatably housed within the receiving groove, with a portion of the spherical wheel protruding from the receiving groove. The spherical wheel has rotational degrees of freedom in the X, Y, and Z axes within the receiving groove. The method of use includes the following steps: (1) Install the ribbed groove core mold onto the spindle of the spinning machine, and then fix the cylindrical blank with a wall thickness of t onto the ribbed groove core mold; (2) The spherical spinning wheel is fixedly connected to the spinning wheel frame of the spinning machine through its spinning wheel support. The end of the spherical spinning wheel protrudes from the receiving groove and is close to the outer periphery of the spindle of the spinning machine. The radius r of the spherical spinning wheel and the wall thickness t of the cylindrical blank satisfy the following relationship: ； Wherein, α is the forming angle formed by the axial front end of the spherical swivel and the cylindrical blank, and the value of the forming angle α is 20° to 30°; (3) Start the spinning machine. The cylindrical blank rotates around the spindle at a set speed under the drive of the core mold with ribs. The spherical spinning wheel moves radially and axially at a set feed ratio under the drive of the spinning wheel frame. When the spherical spinning wheel contacts the cylindrical blank, it rotates and rolls the cylindrical blank to achieve the filling of internal ribs; wherein, In steps (2) and (3), at least two spherical spinning wheels are evenly distributed around the outer circumference of the cylindrical blank.

2. The method of use according to claim 1, characterized in that, The cylindrical blank is fixed to the core mold with ribbed groove by fixing bolts.

Images