Method for rolling forming a full-contoured stream-lined raceway of a tapered roller bearing

Abstract

The application provides a rolling forming method for a complete conformance streamline raceway of a tapered roller bearing, and belongs to the field of bearing preparation. A blank is designed according to the size of an outer ring of the tapered roller bearing, the size of a bar material for blanking is determined, the blank is obtained by blanking, and the height-diameter ratio of the bar material is controlled to be small during the blanking process. The intermediate material is obtained by upsetting the bar material according to the upsetting ratio, the upsetting ratio of the bar material is controlled to be small during the upsetting process of the bar material, the intermediate material is obtained by extrusion forming and stamping, the blank is punched to obtain a ring blank, the ring blank is rolled by using a full-closed pass to realize the conformance streamline forming of the raceway and obtain a final forging, and the rolling ratio is controlled to be large under the condition that a core roller can be put into the full-closed pass. The application considers the influence of the blanking process on subsequent blank making, designs the volume of the bar material and the blanking diameter, makes the height-diameter ratio of the bar material as small as possible, and reduces the radial flow of the bearing ring metal in this stage. The application considers the influence of the upsetting process on the metal flow in subsequent rolling, designs a reasonable upsetting ratio, makes the upsetting ratio as small as possible, and reduces the adverse influence of uneven deformation in the forging process on the metal streamline distribution.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bearing manufacturing, and particularly relates to a rolling forming method for a complete conformal streamline raceway of a tapered roller bearing. BACKGROUND

[0002] Bearing is a core component of high-end equipment such as industrial mother machine, aero-engine and rail transit, and directly affects the service performance and life of high-end equipment. The bearing mainly consists of a ring, a rolling body and a retainer, wherein the bearing ring is a core component that determines the performance of the bearing, and the raceway fatigue failure is the most common form of bearing failure. Therefore, it is crucial to improve the fatigue performance of the bearing raceway.

[0003] With the rapid development of processing technology, the existing manufacturing can guarantee the bearing precision and realize high-precision processing and manufacturing of the raceway. For example, Chinese patent CN111318630B discloses a near-net composite rolling forming method for an inner ring of a tapered roller bearing. However, the organizational state of the bearing is the key to determine the fatigue performance, and the existing manufacturing lacks control over the organizational state, especially the control over the streamline state of the bearing, which leads to the fact that the performance of the bearing cannot meet the service requirements of high-end equipment, becoming a short board in the manufacturing of high-end equipment. In order to realize high-performance manufacturing of the bearing, the streamline of the bearing raceway must be strictly controlled, and the blanking, blanking and rolling process is the key core process that determines the metal flow and streamline forming. Therefore, it is necessary to organically combine the forging blanking and rolling forming process to obtain the complete conformal streamline distribution state of the tapered roller bearing along the raceway. SUMMARY

[0004] In view of this, the present application provides a rolling forming method for a complete conformal streamline raceway of a tapered roller bearing, which solves the problem that the preparation process of the outer ring of the tapered roller bearing lacks control over the streamline state of the bearing.

[0005] The technical scheme of the present application is as follows: The present application provides a rolling forming method for a complete conformal streamline raceway of a tapered roller bearing, which includes the following steps: S1, designing a blank according to the size of the outer ring of the tapered roller bearing, the outer peripheral wall of one end of the blank in the axial direction is provided with a conical surface, determining the size of the blank and the size of the blank and blanking to obtain a material section, and controlling the height-diameter ratio of the bar to be small during blanking; S2, the bar is upset according to the upsetting ratio to obtain an intermediate material, the upsetting ratio is controlled to be small during the upsetting process of the bar, the intermediate material is formed by extrusion and stamping to obtain a blank, and the blank is punched to form a ring blank; S3, 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 the conformal forming of the raceway streamline and obtain a final forging, and the rolling ratio is controlled to be large under the condition that the core roller can be put into the full-closed pass.

[0006] On the basis of the above technical solution, preferably, step S1 includes the following steps: S11, determining the axial height, bar volume, and blanking diameter of the final forging according to the axial height and volume of the outer ring of the tapered roller bearing; S12, determining the axial height, outer diameter, and axial height and minimum outer diameter of the blank according to the axial height and bar volume of the final forging; S13, determining the blanking length and upsetting ratio of the bar according to the blanking diameter of the bar and blanking to obtain the bar, and controlling the height-to-diameter ratio of the bar to be small in the process of determining the blanking length of the bar.

[0007] More preferably, step S2 includes the following steps: S21, upsetting the rod material according to the upsetting ratio to obtain an intermediate material, and controlling the upsetting ratio to be small during the upsetting process of the rod material; S22, setting an extrusion preforming upper die and an extrusion preforming lower die to form a cavity, and the bottom of the inner circumferential wall of the cavity is also provided with a conical surface, the intermediate material is placed in the cavity for extrusion forming and is punched with a conical punch to obtain a blank, an inner cavity with an inner cross-section of a conical cross-section is formed in the blank, and the inner cavity of the blank retains a skin; S23, punching the blank to remove the skin and obtain a ring blank.

[0008] More preferably, in step S21, the range of the axial height H1 of the intermediate material is,

[0009]

[0010] Where V0 is the volume of the bar, B is the axial height of the final forging, h is the axial height of the cone, D1 is the outer diameter of the blank, and D2 is the minimum outer diameter of the cone.

[0011] More preferably, the axial height h of the conical surface is in the range of 0.2 to 0.3 times the axial height B of the final forging; the minimum outer diameter D2 of the conical surface satisfies,

[0012]

[0013] The value range of n is 1 to 1.1; the outer diameter of the blank is obtained by converting the volume of the bar, the minimum outer diameter of the cone, the axial height of the cone, and the axial height of the final forging.

[0014] More preferably, in step S21, the bar upsetting ratio μ satisfies,

[0015]

[0016] Among them, H1 is the axial height of the intermediate material, and V0 is the volume of the bar.

[0017] More preferably, in step S22, the range of the diameter d1 of the end of the tapered punch is,

[0018]

[0019] Where B is the axial height of the final forging, V a is the volume of the final forging, and d0 is the maximum diameter of the core roll profile.

[0020] More preferably, the rolling ratio in step S3 is determined for,

[0021]

[0022] Where h is the axial height of the cone, D2 is the minimum outer diameter of the cone, and D 1min is the minimum inner diameter of the cavity, S a is the axial cross-sectional area of ​​the final forging, δ is the thickness of the skin, and θ is the punch angle of the tapered punch.

[0023] 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 as small as possible according to the axial height B of the final forging.

[0024] More preferably, when d1=d0, the minimum inner diameter D of the cavity is obtained. 1min .

[0025] The present invention provides a method for rolling a tapered roller bearing with a complete conformal streamline raceway, which has the following beneficial effects compared to the prior art:

[0026] (1) Based on the analysis of the heredity and evolution of metal streamlines during the upsetting, punching and rolling processes, the present invention first designs a blank and sets the outer peripheral wall of the bottom end of the blank to have a tapered surface. Then, by regulating the blank height, tapered surface height, bar upsetting ratio, punch shape and rolling ratio, the radial metal flow of the blank during the pre-forging process is suppressed, the metal streamline distribution is improved, and the metal streamline control of the entire forging process of the tapered roller bearing ring is achieved.

[0027] (2) The present invention takes into account the influence of the blanking process on the subsequent blanking, and the forming mold cavity is designed to be single-conical. The bar volume and blanking diameter are designed to make the bar height-to-diameter ratio as small as possible, thereby reducing the radial flow of the bearing ring metal at this stage; considering the influence of the upsetting process on the subsequent rolling metal flow, a reasonable upsetting ratio is designed to make the upsetting ratio as small as possible, thereby reducing the adverse effect of uneven deformation during the forging process on the metal streamline distribution.

[0028] (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 tapered roller bearing and its raceway through an "hourglass" core roller 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.

[0029] (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

[0030] 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.

[0031] Figure 1 Schematic diagram of the structure of the outer ring forging of a tapered roller bearing of the present invention;

[0032] Figure 2 Schematic diagram of the process of pre-forging the outer ring of a tapered roller bearing in step S2 of the complete conformal streamline rolling process of the present invention;

[0033] Figure 3 It is a front view of the ring blank of the outer ring of the tapered roller bearing of the present invention;

[0034] Figure 4 A cross-sectional view of a ring blank of the outer ring of a tapered roller bearing of the present invention;

[0035] Figure 5 Schematic diagram of the process of pre-forging the outer ring of a tapered roller bearing in step S3 of the complete conformal streamline rolling process of the present invention;

[0036] Figure 6 Schematic diagram of simulated metal streamline distribution of the final forging of the present invention;

[0037] Figure 7 This is a streamline corrosion metallographic diagram of the tapered roller bearing outer ring product of the present invention.

[0038] In the figure: 1. Extrusion preforming upper die; 2. Extrusion preforming lower die; 3. Conical punch; 4. Blank; 5. Continuous skin; 6. Driving roller; 7. Core roller. DETAILED DESCRIPTION

[0039] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0040] like Figure 1shown, in conjunction Figure 2 、 Figure 3 and Figure 4 A method for rolling a full-contoured streamline raceway of a tapered roller bearing, comprising the following steps:

[0041] S1, design a blank 4 according to the size of the outer ring of the tapered roller bearing, a taper surface is formed on the outer peripheral wall of one end of the blank 4, the size of the blank 4 and the size of the blank 4 are determined, and the blank is obtained by blanking, and the height-diameter ratio of the blank is controlled to be small during blanking. Step S1 ensures the optimal distribution of metal flow lines by precisely controlling the blanking process. By reasonably designing the volume and diameter of the blank, the problem of metal radial flow caused by too small diameter and too large radial deformation of the blank is avoided, so that the metal flow line 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 forming, which helps to achieve better streamline distribution.

[0042] The taper surface is provided on the bottom end of the blank 4 to improve the flow path of the metal during forming. Especially for parts with complex geometry such as tapered roller bearing outer rings, the uniformity of metal flow is crucial. Through the design of the taper surface, the metal can be better guided when flowing at the bottom end of the blank, so that the metal flows in the predetermined direction during plastic deformation, thereby avoiding uneven flow and defects. The taper surface can provide a gradually tapered surface to help the metal flow along the surface, reducing the non-uniformity of deformation. Generally, if the bottom end of the outer peripheral wall is a vertical surface, the metal may accumulate locally when flowing, causing poor flow, stress concentration or material shortage. The design of the taper surface provides a gradually changing slope, allowing the metal to flow uniformly inward during deformation, improving overall flowability and fillability. By setting the taper surface, the metal can be more evenly distributed in the die during deformation, avoiding local excessive deformation or insufficient metal flow. Especially for parts with complex geometry, the taper surface can effectively reduce the accumulation of local material and reduce the probability of defects such as cracks.

[0043] S2, according to the upsetting ratio, the intermediate material is obtained by upsetting the bar material, and the upsetting ratio is controlled to be small during the upsetting of the bar material, the intermediate material is formed by extrusion and stamping to obtain the blank 4, and the blank 4 is punched to form a ring blank. By controlling the upsetting ratio, the radial flow of the metal can be effectively inhibited, and the uneven distribution of the metal flow lines can be prevented; the selection of the taper punch shape and the optimization of the stamping process help to limit the radial flow of the metal, concentrate the deformation at the inner diameter position of the ring blank, and avoid vortex defects.

[0044] S3, a drive roller 6 and a core roller 7 are arranged to form a fully closed pass. The ring blank is rolled using the fully closed pass to achieve conformal raceway flow lines to produce the final forging. The rolling ratio is controlled to a maximum value, provided that the core roller 7 can fit into the fully closed pass. During the raceway formation process, the rolling ratio must be strictly controlled to ensure the continuity and density of the flow lines, and to ensure a tight and uniform metal structure in the raceway, which is beneficial for improving the fatigue performance of the bearing. Controlling the appropriate rolling ratio and conformal distribution of the metal flow lines can optimize the strength, toughness, and wear resistance of the bearing outer ring, thereby extending the bearing's service life.

[0045] exist Figure 4 In a preferred embodiment shown, step S1 includes the following steps:

[0046] S11, determine the axial height, bar volume, and blanking diameter of the final forging based on the axial height and volume of the outer ring of the tapered roller bearing.

[0047] Specifically, first, under the guidance of the ring blank 4 design principle of constant volume, the bar volume is determined to be V0 = V a +V b , where V a is the final forging volume, V b The volume of the waste core used for blank punching is the volume of the skin 5.

[0048] The blanking diameter D0 can be expressed as,

[0049]

[0050] Among them, μ is the upsetting ratio of the material segment, and H1 is the height of the intermediate material obtained after the bar is upset.

[0051] S12, determine the axial height, outer diameter D1, axial height h of the tapered surface, and minimum outer diameter D2 of the blank 4 based on the axial height of the final forging and the bar volume. The axial height of the blank 4 is the same as the axial height B of the final forging; the minimum outer diameter D2 of the tapered surface is essentially the outer diameter of the bottom end face of the blank 4. The outer diameter of the outer ring of the tapered roller bearing is fixed, that is, the outer diameter of the final forging or the outer diameter D1 of the blank 4 is fixed. The value of D1 is,

[0052]

[0053] Among them, V 内孔 is the volume of the inner cone of the blank 4, or the volume of the inner cavity of the blank 4 before the skin 5 is removed by punching, and its value is,

[0054]

[0055] Among them, δ is the thickness of the skin 5, θ is the punch angle of the tapered punch 3, and d1 is the end diameter of the tapered punch 3, which is also the inner hole diameter of the portion of the ring blank where the skin 5 is removed.

[0056] S13, based on the bar stock's cutting diameter, determines the bar stock's cutting length and upset ratio, and then cuts the bar stock to obtain the bar stock. During the process of determining the bar stock's cutting length, the bar stock's height-to-diameter ratio is minimized. Once the cutting diameter is calculated, the largest possible standard bar stock diameter is selected in accordance with national standard GB702-72 to minimize the bar stock's height-to-diameter ratio. Finally, the corrected bar stock length and upset ratio are determined for the cutting process. Bar stock with a smaller height-to-diameter ratio can reduce radial metal flow during the forming process, avoiding problems such as uneven local streamlines and asymmetric deformation. Finally, the corrected cutting length and upset ratio are obtained, and the bar stock is then cut according to the determined segment size to obtain the segment stock.

[0057] exist Figure 2 In a preferred embodiment shown, step S2 includes the following steps:

[0058] S21, upsetting the bar stock according to the upsetting ratio to obtain an intermediate stock. During the upsetting process, the upsetting ratio is controlled to be small. The purpose of controlling the upsetting ratio is to ensure that the blank 4 can be smoothly formed in subsequent steps by achieving a reasonable degree of metal compression, without excessive material accumulation or uneven flow.

[0059] S22, an extrusion preforming upper die 1 and an extrusion preforming lower die 2 are set to form a cavity. In order to reduce the adverse effects of uneven deformation on the distribution of metal streamlines during the forging process, the mold cavity shape is designed to be a single cone, so the bottom of the inner wall of the cavity is also provided with a cone. The intermediate material is placed in the cavity for extrusion forming and a conical punch 3 is used for punching to obtain a blank 4. An inner cavity with a conical inner cross-section is formed in the blank 4, and a skin 5 is retained in the inner cavity of the blank 4. The conical punch 3 forms an inner cavity with a conical cross-section in the blank 4, so that the metal can flow along the wall of the mold to form a preliminary blank shape with an inner cone, avoiding uneven streamlines or local metal concentration, and providing an ideal foundation for subsequent rolling forming.

[0060] S23, punching the blank 4 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.

[0061] exist Figure 3 In a preferred embodiment shown in FIG. 1 , in step S21 , the range of the axial height H1 of the intermediate material is,

[0062]

[0063] Among them, V0 is the volume of the bar, B is the axial height of the final forging, h is the axial height of the tapered surface, D1 is the outer diameter of the billet 4, and D2 is the minimum outer diameter of the tapered surface. Since the extrusion forming process is to extrude the roughened intermediate material into the billet 4, the intermediate material will be extruded from a smaller axial height to a larger height of the billet 4 during the process. Therefore, the maximum value of the intermediate material is not greater than 0.9 times the axial height of the billet 4. At the same time, during the forging or rolling forming process, the axial height of the billet (i.e., the length of the billet) directly affects the flow pattern of the metal. If the axial height of the intermediate material is too small, the metal may be excessively concentrated in certain areas of the mold cavity during the forming process, causing local excessive deformation or material waste, which may eventually lead to geometric shape and dimensional deviations of the product, and may also cause insufficient metal flow in the mold, resulting in poor forming. Therefore, the minimum value of the axial height of the intermediate material is also limited.

[0064] exist Figure 3 In a preferred embodiment shown, the axial height h of the conical surface is in the range of 0.2 to 0.3 times the axial height B of the final forging. During the forging process, the bottom of the blank 4 usually needs to guide the metal flow through the conical surface to ensure that the metal can evenly fill the mold; if the axial height of the conical surface is too large, it will lead to increased resistance to metal flow, causing local deformation difficulties, and may even lead to material shortages or material waste; on the contrary, if the axial height of the conical surface is too small, the effect of the conical surface is insufficient, and the metal flow may be too concentrated, resulting in excessive local stress, thereby increasing the risk of defects. Limiting the ratio of the axial height of the conical surface relative to the axial height of the final forging can avoid the problem of uneven flow while ensuring the guiding effect of the conical surface, ensuring smooth flow and uniform deformation of the metal.

[0065] The minimum outer diameter D2 of the cone satisfies,

[0066]

[0067] The value of n ranges from 1 to 1.1. The design of the minimum outer diameter of the cone surface needs to be coordinated with the wall thickness and structural requirements of the forging. For example, if the final forging has a thin-walled structure, the minimum outer diameter of the cone surface may need to be smaller to prevent the metal from filling the die smoothly. For thicker forgings, the minimum outer diameter of the cone surface may be relatively large to ensure the stability of metal flow and avoid material flow difficulties caused by excessive compression.

[0068] The outer diameter of the blank 4 is calculated based on the bar volume, the minimum outer diameter of the tapered surface, the axial height of the tapered surface, and the axial height of the final forging.

[0069] exist Figure 4 In a preferred embodiment shown in FIG. 1 , in step S21 , the upsetting ratio μ of the bar material satisfies,

[0070]

[0071] Among them, H1 is the axial height of the intermediate material, and V0 is the volume of the bar.

[0072] exist Figure 2 In a preferred embodiment shown in FIG. 2 , in step S22 , when a tapered punch 3 is used for reverse extrusion, in order to reduce the contact area between the tapered punch 3 and the hard-to-deform area of ​​the blank 4 and concentrate the deformation during the punching process on the inner diameter position of the inner cavity of the blank 4 , a small-diameter tapered punch 3 is used for punching and forming; at the same time, it is also necessary to ensure that the core roller 7 can smoothly enter the die during the subsequent rolling of the ring blank. Therefore, the value range of the end diameter d1 of the tapered punch 3 is,

[0073]

[0074] Where B is the axial height of the final forging, V a is the volume of the final forging, and d0 is the maximum diameter of the core roller 7 profile.

[0075] exist Figure 5 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 roller 7 can be smoothly placed in the die. Therefore, the rolling ratio in step S3 is determined as follows: for,

[0076]

[0077] Where h is the axial height of the cone, D2 is the minimum outer diameter of the cone, and D 1min is the minimum inner diameter of the cavity, S a is the axial cross-sectional area of ​​the final forging, δ is the thickness of the skin 5, and θ is the punch angle of the tapered punch 3.

[0078] 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 minimized based on the final axial height B of the forged piece. Specifically, when the ring blank height B is large, the punch angle θ at the end of the tapered punch 3 should be appropriately minimized. The edge of the tapered punch 3 is rounded to a radius R = 0.15d1 + (1-2) mm, with the standard size applied upward. Punching is then performed to remove the skin 5, resulting in a ring blank with a single tapered outer wall end.

[0079] exist Figure 4 In a preferred embodiment shown in FIG, when d1 = d0, the minimum inner diameter D of the cavity is obtained. 1min .

[0080] The present invention further provides an outer ring of a tapered roller bearing, which is manufactured by the complete conformal streamline raceway rolling forming method of the tapered roller bearing of any of the above embodiments. Specifically:

[0081] like Figure 1 As shown in the figure, a tapered roller bearing outer ring made of GCr15 is used. The final forging is composed of two outer rings mirror-symmetrical along the radial surface. The outer diameter, minimum inner diameter, height of the inner surface cylindrical part, and total height of the final forging are D = 234.5mm, d = 189.5mm, b = 29mm, and B = 165mm respectively. The volume of the final forging is V a =1966720mm 3 , the final axial cross-sectional area S of the forging a =2897.16mm 2 The thickness of the ring blank 4 including the skin 5 is δ=9mm, and the maximum diameter of the core roller 7 is d0=45mm. The preparation process is implemented as follows:

[0082] (1) Determine the cutting size

[0083] According to the above technical solution, the diameter of the end of the tapered punch 3 should be controlled as follows: 45mm<d1≤55.44mm, then d1=48mm, and the volume of the waste core for blank punching (i.e. the volume of the skin 5) is V b =16286.016mm 3 , so the volume of the blanked bar is,

[0084] V0=1966720+16286.016=1983006.016mm 3 .

[0085] Take the inner hole taper of ring blank 4 as θ = 5°, then V 内孔 =473253.408mm 3 Since h = (0.2-0.3) × 165 = 33-49.5 mm, and D2 = (1-1.1) × 123.19 = 123.19-135.51 mm, we assume h = 45 mm and D2 = 125 mm, yielding D1 = 139.61 mm. Therefore, 134.08 mm ≤ H1 ≤ 148.5 mm, so we assume H1 = 140 mm. To minimize metal flow line bending during forging, the upset ratio of the material segment is controlled to μ ≤ 1.33. First, substituting μ = 1.3 into the formula for calculating the blanking diameter D0 yields D0 = 117.8 mm. Based on the national standard GB702-72, we select the standard bar diameter and finally set D0 = 120 mm, resulting in a blanking bar length H0 = 175.34 mm and an upset ratio μ = 1.252. Subsequently, blanking is performed according to the bar size.

[0086] (2) Pre-forging

[0087] like Figure 2 As shown, the die forging is first performed on a press at a speed of 10 mm / s. After upsetting, the blank is as shown in FIG. Figure 3 As shown. The blank 4 is then extruded on a press using an extrusion preforming upper die 1, an extrusion preforming lower die 2, and a tapered punch 3, leaving the skin 5 at the bottom of the blank's inner cavity. The end diameter d1 of the tapered punch 3 is 48 mm, and the punch angle θ is selected to be 5°. The smaller punch end diameter and punch angle reduce the contact area between the tapered punch 3 and the hard-to-deform area of ​​the blank 4, concentrating deformation during the punching process on the inner diameter of the blank 4's inner hole. The metal streamline distribution is not significantly altered during the punching process.

[0088] The edge of the end of the conical punch 3 is rounded, and the radius of the fillet is R = 0.15 × 48 + (1 ~ 2) mm = 8.2 ~ 9.2 mm. The standard value is R = 10 mm. The radius of the end of the conical punch 3 cannot be too small to avoid the difficulty of metal flow at the corner, resulting in severe deformation and cutting of the metal flow line. Then punching is performed to remove the skin 5, and the following is obtained: Figure 4 The ring blank 4 is shown.

[0089] (3) Rolling forming

[0090] like Figure 5 As shown, the rolling apparatus includes a drive roller 6 and a core roller 7. The ring rolling mill uses a rolling pass to roll the inner tapered ring blank. By designing the rolling pass geometry and controlling the rolling deformation, the raceway is nearly net-shaped, resulting in a ball bearing outer ring forging. To achieve a near-net-shape raceway, the roll pass uses a fully closed pass, whose geometry matches the cross-sectional shape of the forged raceway.

[0091] The parameters determined in the pre-forging process design process give the outer diameter of the ring blank D1 = 47.943 mm, and the minimum inner diameter of the mold cavity under extrusion preforming is D 1min =138.18mm.

[0092] The ring billet rolling ratio of the embodiment of the present invention is: Meet the forming requirements.

[0093] The simulated metal streamline distribution and streamline corrosion metallography of the tapered roller bearing outer ring obtained in the above embodiment are as follows: Figure 6 、 Figure 7 As shown, it can be found that the metal streamlines of the outer ring forging of the embodiment of the present invention are continuously distributed along the shape, and the streamlines are basically distributed along the raceway contour, without turbulent eddy currents and streamline outcrops.

[0094] This shows that the method of the present invention can improve the distribution of metal streamlines by regulating the shape of the ring blank 4, the bar upsetting ratio, the punch shape, and the rolling ratio, and obtain good metal streamlines that are continuously distributed along the geometric shape of the bearing ring forging.

[0095] 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 rolling a tapered roller bearing with a complete conformal streamline raceway, characterized in that: The following steps are involved: S1, designing a blank (4) according to the size of the outer ring of the tapered roller bearing, a tapered surface being provided on the outer peripheral wall of one axial end of the blank (4), determining the size of the blanked bar and the size of the blank (4) and blanking to obtain a material segment, and controlling the height-to-diameter ratio of the bar to be minimized during the blanking process; S2, upsetting the bar material according to the upsetting ratio to obtain an intermediate material, and controlling the upsetting ratio to be small during the upsetting process of the bar material, extruding and punching the intermediate material to obtain a blank (4), and punching the blank (4) to produce a ring blank; S3, a driving roller (6) and a core roller (7) are provided to form a fully closed die, the ring blank is rolled using the fully closed die to achieve a raceway streamline forming to obtain a final forging, and the rolling ratio is controlled to be large under the condition that the core roller (7) can be placed in the fully closed die; The step S2 includes the following steps: S21, upsetting the bar material according to the upsetting ratio to obtain an intermediate material, and controlling the upsetting ratio to be small during the upsetting process of the bar material; S22, an extrusion preforming upper die (1) and an extrusion preforming lower die (2) are provided to form a cavity, the inner wall bottom of the cavity is also provided with a conical surface, the intermediate material is placed in the cavity for extrusion forming and punched with a conical punch (3) to obtain a blank (4), an inner cavity with a conical cross section is formed in the blank (4), and a skin (5) is retained in the inner cavity of the blank (4); S23, punching the blank (4) to remove the skin (5) and obtain a ring blank; In step S21, the axial height of the intermediate material is H The value range of 1 is, ， in, V 0 is the volume of the bar, in mm 3 , B is the axial height of the final forging, in mm, h is the axial height of the conical surface of the blank (4), in mm, D 1 is the outer diameter of the blank (4), in mm, D 2 is the minimum outer diameter of the conical surface of the blank (4), in mm; the axial height of the conical surface of the blank (4) is h The value range is the axial height of the final forging B 0.2~0.3 times; The minimum outer diameter of the conical surface of the blank (4) D 2 Satisfaction, ， Among them, the value range of n is 1~1.1; The outer diameter of the blank (4) is obtained by converting the volume of the bar, the minimum outer diameter of the conical surface, the axial height of the conical surface, and the axial height of the final forging; In step S21, the bar material's upsetting ratio μ satisfy, ， in, H 1 is the axial height of the intermediate material, in mm, V 0 is the volume of the bar, in mm 3 ; In step S22, the end diameter of the tapered punch (3) is d The value range of 1 is, ， in, B is the axial height of the final forging, in mm, V a is the volume of the final forging, in mm 3 , d 0 is the maximum diameter of the core roller (7) profile, in mm; Determine the rolling ratio in step S3 φ for, ， in, h is the axial height of the conical surface of the blank (4), in mm, D 2 is the minimum outer diameter of the conical surface of the blank (4), in mm, D 1min is the minimum inner diameter of the cavity, in mm, S a is the axial cross-sectional area of ​​the final forging, in mm 2 , δ is the thickness of the skin (5), in mm, θ is the punch angle of the conical punch (3).

2. The method for rolling a tapered roller bearing with a complete conformal streamline raceway according to claim 1, characterized in that: The step S1 includes the following steps: S11, determining the axial height, bar volume, and blanking diameter of the final forging according to the axial height and volume of the outer ring of the tapered roller bearing; S12, determining the axial height, outer diameter, axial height of the conical surface, and minimum outer diameter of the blank (4) according to the axial height of the final forging and the volume of the bar; S13, determining the cutting length and upsetting ratio of the bar according to the cutting diameter of the bar and cutting to obtain the bar, and controlling the height-to-diameter ratio of the bar to be small during the process of determining the cutting length of the bar.

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

4. The method for rolling a tapered roller 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 cavity is obtained D 1min .

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