A precision rolling forming method for a complete conformal streamline raceway of a ball bearing

Abstract

The application provides a precise rolling forming method for a complete conformal streamline raceway of a ball bearing, and belongs to the field of ball bearing preparation.The length of a material section and a upsetting ratio of blanking are determined according to the axial height and volume of a ring blank of the ball bearing, and the height-diameter ratio of the material section is controlled to be small; the material section is upset according to the determined upsetting ratio, and the upsetting ratio of the material section is controlled to be small; and then the material section is put into a die to be stamped into the ring blank; a driving roller and a core roller are arranged to form a full-closed pass, and the ring blank is rolled by using the full-closed pass to realize conformal forming of a raceway streamline, and the rolling ratio is controlled to be large under the condition that the core roller can be put into a model cavity.The application considers the influence of the blanking process on subsequent blank making, designs the volume and blanking diameter of the material section, makes the height-diameter ratio of the material section as small as possible, and reduces the radial flow of the bearing ring metal in this stage; the upsetting process is considered to have an influence on the metal flow in subsequent rolling, the upsetting ratio is made as small as possible, and the adverse influence of uneven deformation in the forging process on the metal streamline distribution is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of ball bearing rolling, and in particular to a method for accurately rolling a ball bearing complete conformal streamline raceway. Background Art

[0002] Bearings are core components of high-end equipment such as industrial machine tools, aircraft engines, and rail transit systems, directly impacting their performance and lifespan. Bearings primarily consist of outer rings, balls, and inner cages. The outer rings are the core component that determines bearing performance, and raceway fatigue failure is the most common form of bearing failure. Therefore, improving the fatigue performance of bearing raceways is crucial.

[0003] With the rapid development of processing technology, existing manufacturing can guarantee the accuracy of bearings and achieve high-precision processing and manufacturing of the raceways. For example, patent CN1085733C discloses a continuous annealing furnace, rolling bearings, annealing methods, and methods for manufacturing inner and outer rings of deep-groove ball bearings. However, the structural state of the bearing is the key to determining fatigue performance. Existing manufacturing is very lacking in control of the structural state, especially the control of the streamline state of the bearing is almost blank, resulting in the inability of bearing performance to meet the service requirements of high-end equipment, which has become a shortcoming in the manufacturing of high-end equipment. In order to achieve high-performance bearing manufacturing, the streamline of the bearing raceway must be strictly controlled, and the blanking, billet making, and rolling processes are the key core processes that determine metal flow and streamline forming. To this end, it is necessary to organically combine the forging billet making and rolling forming processes to obtain a streamline distribution state that follows the complete shape of the ball bearing along the raceway. Summary of the Invention

[0004] In view of this, the present invention proposes a method for accurately rolling a ball bearing's complete conformal streamline raceway to solve the problem that the current preparation process of the outer ring of the ball bearing lacks control over the streamline state of the bearing.

[0005] The technical solution of the present invention is implemented as follows: The present invention provides a method for precise rolling forming of a complete conformal streamline raceway of a ball bearing, comprising the following steps: S1, determining the length and upsetting ratio of the blanking material according to the axial height and volume of the ring blank of the ball bearing, and controlling the height-to-diameter ratio of the bar material to be small; S2, upsetting the material segment according to the upsetting ratio determined in step S1, and controlling the upsetting ratio of the material segment to be small, and then placing the material segment into a mold for stamping into a ring blank; S3, arranging a driving roller and a core roller to form a fully closed hole, and using the fully closed hole to roll the ring blank to achieve conformal streamline forming of the raceway, and controlling the rolling ratio to be large under the condition that the core roller can be placed in the mold cavity.

[0006] On the basis of the above technical solution, preferably, step S1 includes the following steps: S11, determining the volume of the bar according to the axial height and volume of the ring blank of the ball bearing; S12, determining the cutting diameter of the material segment according to the volume of the bar; S13, correcting the cutting segment length and upsetting ratio according to the cutting diameter of the material segment, controlling the height-to-diameter ratio of the bar to be smaller during correction, and cutting to obtain the material segment.

[0007] More preferably, the blanking diameter D0 of the material section in step S12 is determined as follows:

[0008]

[0009] Among them, V0 is the bar volume, μ is the material segment upsetting ratio, B is the ring blank height of the ball bearing outer ring and is the final forging height of the ball bearing outer ring.

[0010] More preferably, the height-to-diameter ratio of the bar is reduced by controlling the diameter of the standard bar to be larger.

[0011] On the basis of the above technical solution, preferably, step S2 includes the following steps: S21, upsetting the material segment according to the upsetting ratio, and controlling the upsetting ratio of the material segment to be small; S22, setting an extrusion preforming upper die and an extrusion preforming lower die to form a model cavity, placing the material segment into the model cavity, and using a conical punch to extrude the blank, forming an inner cavity with a conical cross-section in the blank, and retaining the skin in the inner cavity of the blank; S23, punching the blank to remove the skin, and obtaining a ring blank with an inner conical cross-section.

[0012] More preferably, the value range of the material segment upsetting ratio μ in step S21 is,

[0013]

[0014] Among them, V0 is the bar volume, B is the ring blank height of the ball bearing outer ring and is the final forging height of the ball bearing outer ring.

[0015] More preferably, the range of the diameter d1 of the end of the tapered punch in step S22 is,

[0016]

[0017] Where d0 is the maximum diameter of the core roller profile, V a is the forging volume of the ball bearing outer ring.

[0018] More preferably, the rolling ratio in step S3 is determined for,

[0019]

[0020] Among them, δ is the thickness of the skin, D1min is the minimum inner diameter of the model cavity, S a is the axial cross-sectional area of ​​the ball bearing outer ring forging, and θ is the punch angle of the tapered punch.

[0021] More preferably, the punch angle θ of the tapered punch is 2° to 10°, and the punch angle θ of the tapered punch is controlled to be smaller according to the height B of the ring blank.

[0022] More preferably, when d1=d0, the minimum inner diameter D of the model cavity is obtained. 1min .

[0023] The method for accurately rolling a ball bearing raceway with a complete conformal streamlined raceway according to the present invention has the following beneficial effects compared to the prior art:

[0024] (1) Based on the analysis of the heredity and evolution of metal streamlines during the upsetting, punching and rolling processes, the present invention controls the bar upsetting ratio, punch shape and rolling ratio to suppress the radial metal flow of the billet during pre-forging, improve the metal streamline distribution, and realize metal streamline control throughout the forging process of ball bearing rings.

[0025] (2) The present invention takes into account the impact of the blanking process on subsequent blanking, designs the bar volume and blanking diameter, makes the bar height-to-diameter ratio as small as possible, and reduces the radial flow of the bearing ring metal at this stage; takes into account the impact of the upsetting process on the subsequent rolling metal flow, designs a reasonable upsetting ratio, makes the upsetting ratio as small as possible, and reduces the adverse effect of uneven deformation in the forging process on the metal streamline distribution.

[0026] (3) The present invention takes into account the influence of rolling deformation on the final distribution of bearing raceway streamlines, and directly forms the outer ring of the ball bearing and its raceway through a core roller with protrusions to achieve near-net forming of the raceway; at the same time, it controls a reasonable amount of rolling deformation to obtain dense metal streamlines that are continuously distributed along the raceway contour, ultimately improving the raceway fatigue performance and bearing service life.

[0027] (4) The present invention designs a reasonable punching angle and tries to eliminate unfavorable streamline distribution through the punching process. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 It is a structural schematic diagram of the ball bearing outer ring forging of the present invention;

[0030] Figure 2 Flow chart for blanking step S2 of the complete conformal streamline raceway rolling process of the ball bearing outer ring forging of the present application;

[0031] Figure 3 Blank section view of the ring blank of the ball bearing outer ring of the present application;

[0032] Figure 4 Flow chart for blanking step S3 of the complete conformal streamline raceway rolling process of the ball bearing outer ring forging of the present application;

[0033] Figure 5 Schematic diagram of simulated metal streamline distribution of the ball bearing outer ring forging of the present application;

[0034] Figure 6 Streamline corrosion metallographic diagram of the ball bearing outer ring forging of the present application. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0036] As shown in Figure 1 in combination with Figure 2 , Figure 3 and Figure 4 , a complete conformal streamline raceway precision rolling forming method of a ball bearing of the present application comprises the following steps:

[0037] S1, determine the length of the material section and the upsetting ratio according to the axial height and volume of the ring blank of the ball bearing, and control the height-diameter ratio of the bar material to be small. The purpose of step S1 is to prepare suitable bar material for the subsequent blanking and forming process. By precisely controlling the blanking process, the quality of the metal streamline distribution is ensured. By reasonably designing the volume and diameter of the bar material, the problem of metal radial flow caused by too small diameter and too large radial deformation of the bar material is avoided, so that the metal streamline in the subsequent processing is more ideal; reducing the height-diameter ratio can reduce the defects caused by uneven flow of the bearing outer ring during the forming process, which helps to achieve a better streamline distribution.

[0038] S2, upsetting the material segment according to the upsetting ratio determined in step S1, controlling the upsetting ratio of the material segment to be small, and then placing the material segment into a die for stamping to form a ring blank. The purpose of step S2 is to preliminarily form the ring blank of the ball bearing outer ring through upsetting and stamping. Controlling the plastic flow of the metal during the upsetting process is crucial for subsequent forming. By controlling the upsetting ratio, the radial flow of the metal can be effectively suppressed, preventing uneven distribution of metal streamlines; the selection of the tapered punch shape and the optimization of the stamping process help to limit the radial flow of the metal, so that the deformation is concentrated on the inner diameter of the ring blank, avoiding the generation of eddy current defects.

[0039] In step S3, the drive roller 6 and the core roller 7 are arranged to form a fully enclosed pass. The ring blank is rolled using the fully enclosed pass to achieve conformal roller raceway streamline formation. The rolling ratio is controlled to be as large as possible while the core roller 7 can fit into the mold cavity. During the roller raceway formation process in step S3, the rolling ratio must be strictly controlled to ensure the continuity and density of the streamlines, as well as the tight and uniform metal structure at the roller raceway, which is beneficial for improving the fatigue performance of the bearing. Controlling the appropriate rolling ratio and conformal distribution of the metal streamlines can optimize the strength, toughness, and wear resistance of the bearing outer ring, thereby extending the bearing's service life.

[0040] exist Figure 1 In a preferred embodiment shown, step S1 includes the following steps:

[0041] S11, first, under the guidance of the ring blank design principle of equal axial height and constant volume, determine the bar volume V0=V according to the axial height and volume of the ball bearing ring blank. a +V b , V a is the final forging volume of the ball bearing outer ring, V b is the volume of the waste core for blank punching (i.e. the volume of the skin 5);

[0042] S12, determine the blanking diameter D0 of the material segment based on the bar volume. Under reasonable process conditions, a larger blanking diameter is more conducive to production. However, if the blanking diameter of the bar is too large, it will cause blanking defects such as uneven end surfaces during the subsequent upsetting process, which are difficult to correct. If the blanking diameter is too small, that is, the height-to-diameter ratio is too large, the outer diameter of the material cake is large, which means that the metal flows radially and the streamlines are severely bent and deformed, affecting the final streamline distribution of the product.

[0043] S13, based on the calculated blanking diameter D0, a standard bar stock diameter as large as possible is selected in accordance with the design standards for the outer ring of a ball bearing. This minimizes the bar stock's aspect ratio. A bar stock with a smaller aspect ratio reduces radial metal flow during the forming process, avoiding problems such as uneven local streamlines and asymmetric deformation. Finally, the corrected blanking length and upsetting ratio are obtained. Then, the stock is blanked according to the determined segment size to obtain the segment.

[0044] exist Figure 1 In a preferred embodiment shown in FIG. 1 , the blanking diameter D0 of the material section in step S12 is determined to be,

[0045]

[0046] Among them, V0 is the bar volume, μ is the material segment upsetting ratio, B is the ring blank height of the ball bearing outer ring and is the final forging height of the ball bearing outer ring.

[0047] exist Figure 1 In a preferred embodiment shown, the standard bar diameter is controlled to be larger so as to reduce the aspect ratio of the bar. The aspect ratio refers to the ratio between the length of the bar (i.e., the height of the bar) and its diameter (i.e., the diameter of the bar). A bar with a large aspect ratio means that the length is relatively long and the diameter is small. During the plastic deformation process, the metal needs to flow in the longer direction, and the flow speed and direction may be more uneven. Conversely, a bar with a small aspect ratio means that the length is relatively short and the diameter is large. Such a bar will have a more stable and uniform flow of metal during the forming process. In a bar with a larger diameter, the metal is more likely to flow evenly in the radial direction (i.e., the transverse direction), avoiding the directional flow problem that is prone to occur in a bar with a small diameter (for example, uneven material accumulation or local excessive density). During the forming process, for a bar with a large aspect ratio, the deformation of the metal mainly occurs in the long direction, and the deformation in this direction is more likely to be uneven. For example, the metal may be concentrated in certain areas and stretched too much, or compressed too much, resulting in uneven plastic deformation; a smaller aspect ratio means that the deformation direction of the metal is more uniform, which helps to obtain more stable and uniform metal streamlines during the forming process; by controlling the larger bar diameter, the deformation process of the billet can be more stable, reducing defects (such as cracks, etc.) caused by uneven metal flow. In this way, the formed billet 4 can also maintain a high degree of stability during subsequent processing. In the case of a large aspect ratio, the metal often requires a longer flow path, which is prone to local metal accumulation or local excessive compression. This problem is more prominent in complex mold shapes. By controlling the diameter of the bar and reducing the aspect ratio, the metal flows more evenly in the mold, thereby avoiding metal accumulation and excessive compression, which helps to improve the forming accuracy.

[0048] exist Figure 2 In a preferred embodiment shown, step S2 includes the following steps:

[0049] S21, upsetting the material segment according to the upsetting ratio. To minimize the adverse effects of uneven deformation on metal flow distribution during the forging process, the upsetting ratio of the material segment needs to be controlled within a relatively small range. Upsetting involves compressing the bar stock into the initial shape of the blank 4, primarily by deforming the metal material through pressure. The purpose of controlling the upsetting ratio is to ensure smooth forming of the blank 4 in subsequent steps by achieving a reasonable degree of metal compression, without excessive material accumulation or uneven flow.

[0050] After upsetting is complete, the blank 4 is placed in a die for extrusion. The die comprises an upper extrusion preforming die 1 and a lower extrusion preforming die 2, which together form a mold cavity. The material segment is placed in the mold cavity and extruded using a tapered punch 3. This creates a conical inner cavity within the blank 4, retaining a skin 5. The tapered punch 3 creates a conical inner cavity within the blank 4, allowing metal to flow along the die walls, forming a preliminary inner tapered blank shape. This avoids uneven flow lines or localized metal concentration, providing an ideal foundation for subsequent roll forming.

[0051] S23, punching is performed on the blank 4 obtained in step S22 to remove the skin 5. The punch used for punching to remove the skin 5 is a cylindrical punch instead of the conical punch 3, and finally a ring blank with an inner conical cross section is obtained.

[0052] exist Figure 2 In a preferred embodiment shown in FIG. 1 , the value range of the material segment upsetting ratio μ in step S21 is,

[0053]

[0054] Among them, V0 is the bar volume, B is the ring blank height of the ball bearing outer ring and is the final forging height of the ball bearing outer ring.

[0055] exist Figure 3 In a preferred embodiment shown, in order to reduce the contact area between the punch and the hard-to-deform area of ​​the blank and concentrate the deformation at the inner diameter during the punching process, a small-diameter tapered punch is used for punching. At the same time, it is necessary to ensure that the core roller 7 can smoothly enter the die during ring rolling. Therefore, the end diameter d1 of the tapered punch 3 in step S22 has a value range of

[0056]

[0057] Wherein, d0 is the maximum diameter of the core roller 7, V a It can be seen that the end diameter d1 of the tapered punch 3 should be larger than the maximum diameter of the core roller 7 profile, but smaller than a certain ratio of the forged diameter of the ball bearing outer ring; 0.72 is a preferred parameter for calculating this ratio.

[0058] exist Figure 4 In a preferred embodiment shown, the rolling ratio is the ratio of the longitudinal cross-sectional area of ​​the ring billet before and after rolling. In order to obtain a good and dense metal streamline distribution, the rolling forming should be carried out with a large rolling ratio as much as possible while ensuring that the core roll can be smoothly placed in the die. The rolling ratio in step S3 is determined as follows: for,

[0059]

[0060] Among them, δ is the thickness of the skin 5, D 1min is the minimum inner diameter of the model cavity, S a is the axial cross-sectional area of ​​the ball bearing outer ring forging, and θ is the punch angle of the tapered punch 3.

[0061] exist Figure 2 In a preferred embodiment shown, the punch angle θ of the tapered punch 3 is between 2° and 10°. This angle is adjusted based on the ring blank height B. When the ring blank height B is large, the angle θ should be appropriately reduced. Controlling the punch angle of the tapered punch 3 is intended to eliminate unfavorable streamline distribution, ensuring that metal streamlines are more consistent with expectations during subsequent processing and avoiding unfavorable structural defects. A smaller punch angle θ means the punch's tapered portion is more gently tapered. A smaller punch angle minimizes directional variation in metal flow, helping the metal fill the die cavity more evenly and avoiding excessive localized plastic deformation. Specifically, a smaller punch angle ensures uniform metal flow along the die wall during punching, reducing excessive stretching or squeezing of the metal in localized areas and minimizing the risk of uneven streamlines. The punch angle influences the rolling ratio. A larger punch angle results in a smaller rolling ratio, a larger inner diameter of the forming cavity, greater radial and axial deformation of the blank during filling, and increased curvature of the internal streamlines of the ring blank.

[0062] exist Figure 3 In a preferred embodiment shown in FIG, a forming concave mold cavity is provided in the driving roller 6, and the driving roller 6 and the core roller 7 form a fully closed hole; when punching, the internal volume of the forming concave mold cavity V 型腔 for,

[0063]

[0064] The inner diameter D1 of the extrusion preforming mold cavity opened on the extrusion preforming lower die 2 is also the outer diameter of the inner conical section ring blank, and its value is,

[0065]

[0066] Therefore, when d1=d0, the minimum inner diameter D of the mold cavity of the extrusion preforming lower mold 2 is obtained. 1min. The minimum inner diameter determines the flow path of the metal in the mold. If the inner diameter is too large, it will become difficult to control the metal flow, which may lead to uneven forming. If the inner diameter is too small, the punch will still be in the downward process when the metal fills the cavity, which will generate great compressive stress and quickly damage the die cavity. The design of the minimum inner diameter needs to take into account the fluidity of the metal, avoid uneven flow and local accumulation or material shortage, ensure that the metal can be evenly distributed in the mold, and avoid uneven deformation. In addition, the selection of the minimum inner diameter also involves the optimization of the forming pressure. The appropriate inner diameter helps to maintain appropriate pressure during the extrusion process, so that the metal can flow better in the mold, avoiding damage to the mold due to excessive pressure or incomplete forming due to insufficient pressure.

[0067] The present invention further provides a ball bearing outer ring, which is manufactured by the ball bearing complete conformal streamline raceway precision rolling forming method of any of the above embodiments, specifically:

[0068] like Figure 1 As shown in the figure, the material used is GCr15, the bearing ring is 6308 ball bearing outer ring, the outer diameter, inner diameter, raceway inner diameter, height and raceway radius of the ball bearing outer ring forging are D=90.2mm, d=75.75mm, d m =82.16mm, B=23.18mm, R=9.25mm, the outer ring forging volume is V a =35991.3mm 3 , axial cross-sectional area S a =136.337mm 2 The ring blank punching thickness is δ = 4 mm, and the maximum diameter of the core roller 7 is d0 = 14.4 mm. The forging process is implemented as follows:

[0069] (1) Determine the cutting size

[0070] According to the above technical solution, the end diameter of the tapered punch 3 should be controlled to: 14.4mm <d1≤16mm,则取d1=15mm,得到制坯冲孔的废料芯体积为V b =706.858mm 3 , so the blanking volume is V0 = 35991.3 + 706.858 = 36698.158 mm 3 .

[0071] To minimize metal flow line bending during forging, the upset ratio of the material segment is controlled to: μ ≤ 1.55. First, substituting μ = 1.5 into the formula for calculating the blanking diameter D0, we obtain D0 = 36.659 mm. Based on the national standard GB702-72, the standard bar diameter is selected, and finally D0 = 38 mm, resulting in a blanking length H0 = 32.359 mm and an upset ratio μ = 1.396. Subsequently, blanking is performed according to the bar size.

[0072] (2) Pre-forging

[0073] like Figure 2 As shown, firstly, free upsetting is performed on the press at a speed of 10 mm / s. Then, the blank 4 is extruded on the press using the extrusion preforming upper die 1, the extrusion preforming lower die 2 and the tapered punch 3, and the punched skin 5 is left at the bottom of the blank. The punch end diameter d1 = 15 mm, and the punch angle θ = 5° are selected. The smaller punch end diameter and punch angle can reduce the contact area between the punch and the difficult-to-deform area of ​​the blank, so that the deformation during the punching process is concentrated on the inner diameter position, and the metal streamline distribution will not be significantly changed during the punching process. Subsequently, the skin 5 is removed by punching to obtain an inner conical cross-section ring blank, as shown Figure 3 shown.

[0074] (3) Rolling forming

[0075] like Figure 4 As shown, the rolling device includes a driving roller 6 and a core roller 7. The inner conical cross-section ring blank is rolled on the ring rolling machine using the rolling pass. Through the geometric design of the rolling pass and the control of the rolling deformation, the raceway is nearly net-shaped, and the ball bearing outer ring forging is obtained. In order to obtain a near-net-shape raceway, the roll pass adopts a fully closed pass, and the geometry is consistent with the cross-sectional shape of the forging raceway. The parameters determined in the pre-forging process design process result in the outer diameter of the ring blank D1 = 47.943 mm, and the minimum inner diameter of the mold cavity under the extrusion preforming is D 1min =47.228mm. The ring billet rolling ratio of the embodiment of the present invention Meet the forming requirements.

[0076] The outer ring of the 6308 ball bearing obtained in the above embodiment is compared with the traditional cutting-formed ring and the outer ring of the Swedish SKF bearing by the raceway metal streamline. Figure 5 、 Figure 6 As shown, the outer ring forging of the embodiment of the present invention exhibits continuous and conforming metal streamlines, essentially following the raceway profile and lacking turbulent eddy currents. This demonstrates that the present method can improve metal streamline distribution by controlling the bar upsetting ratio, punch shape, and rolling ratio, resulting in well-defined, continuous metal streamlines that conform to the bearing ring forging's geometric shape.

[0077] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for accurately rolling a ball bearing raceway with a complete conformal streamline, characterized by: The following steps are included: S1, determine the blanking length and upsetting ratio according to the axial height and volume of the ball bearing ring blank, and control the height-to-diameter ratio of the bar to be as small as possible; S2, upsetting the material segment according to the upsetting ratio, controlling the upsetting ratio of the material segment to be small, then placing the material segment into a die and punching it into a ring blank, arranging a driving roller (6) and a core roller (7) to form a fully closed hole, and rolling the ring blank using the fully closed hole to achieve raceway streamline forming; S21, upsetting the material segment according to the upsetting ratio, and controlling the upsetting ratio of the material segment to be small, the upsetting ratio of the material segment μ The value range of is, ， in, V 0 is the bar volume, unit is mm 3 , B is the ring blank height of the ball bearing outer ring and the final forging height of the ball bearing outer ring, in mm; S22, setting an extrusion preforming upper die (1) and an extrusion preforming lower die (2) to form a mold cavity, placing the material segment into the mold cavity, and using a conical punch (3) to extrude the blank to obtain a blank (4), forming an inner cavity with a conical cross section in the blank (4), and retaining a skin (5) in the inner cavity of the blank, and the end diameter of the conical punch (3) is d The value range of 1 is, ， in, d 0 is the maximum diameter of the core roller (7) profile, in mm, V a is the forging volume of the outer ring of the ball bearing, in mm 3 ; S23, punching the blank (4) to remove the skin (5), thereby obtaining a ring blank with an inner conical cross section; S3, under the condition that the core roller (7) can be placed in the mold cavity, the rolling ratio is controlled to be large, and the rolling ratio is determined. φ for, ， in, δ is the thickness of the skin (5), in mm, D 1min is the minimum inner diameter of the model cavity, in mm, S a is the axial cross-sectional area of ​​the ball bearing outer ring forging, in mm 2 , θ is the punch angle of the conical punch (3).

2. The method for accurately rolling a ball bearing raceway with a complete conformal streamline according to claim 1, characterized in that: The step S1 includes the following steps: S11, determining the bar volume according to the axial height and volume of the ring blank of the ball bearing; S12, determining the cutting diameter of the material section according to the volume of the bar; S13, correcting the length of the blanking segment and the upsetting ratio according to the blanking diameter of the material segment, correcting and controlling the height-to-diameter ratio of the bar material to be smaller, and blanking to obtain the material segment.

3. The method for accurately rolling a ball bearing raceway with a complete conformal streamline according to claim 2, characterized in that: Determine the cutting diameter of the material segment in step S12 D 0 is, ， in, V 0 is the bar volume, unit is mm 3 , μ is the upsetting ratio of the material segment, B It is the ring blank height of the ball bearing outer ring and the final forging height of the ball bearing outer ring, in mm.

4. The method for accurately rolling a ball bearing with a complete conformal streamline raceway according to claim 3, characterized in that: By controlling the diameter of the standard bar to be larger, the height-to-diameter ratio of the bar is reduced.

5. The method for accurately rolling a ball bearing raceway with a complete conformal streamline according to claim 1, characterized in that: The punch angle of the tapered punch (3) θ 2°~10°, according to the height of the ring blank B Control the punch angle of the tapered punch (3) θ Take the smaller one.

6. The method for accurately rolling a ball bearing with a complete conformal streamline raceway according to claim 1, characterized in that: when d 1= d 0, the minimum inner diameter of the model cavity is obtained D 1min。

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