Tapered roller bearing complete shape follow-up streamline raceway rolling forming method

Abstract

The invention provides a rolling forming method for a complete shape follow-up streamline raceway of a tapered roller bearing, and belongs to the field of bearing preparation. According to the size of an outer ferrule of the tapered roller bearing, a blank is designed, the size of a blanked bar and the size of the blank are determined, blanking is conducted to obtain a material section, and the height-diameter ratio of the bar is controlled to be small in the blanking process; the bar is subjected to upsetting according to the upsetting ratio to obtain an intermediate material, the upsetting ratio is controlled to be small in the upsetting process of the bar, the intermediate material is subjected to extrusion forming and stamping to obtain a blank, and the blank is punched to form a ring blank; and the ring blank is rolled through the fully-closed hole pattern to achieve rolling path streamline follow-up forming to obtain a final forge piece, and the rolling ratio is controlled to be large under the condition that a core roller can be placed in the fully-closed hole pattern. The influence of the blanking process on subsequent blank making is considered, and the bar size and the blanking diameter are designed, so that the height-diameter ratio of the bar is as small as possible, and the radial flow of bearing ring metal at the stage is reduced; and in consideration of the influence of the upsetting process on subsequent rolling metal flow, a reasonable upsetting ratio is designed, so that the upsetting ratio is as small as possible, and the adverse influence of non-uniform deformation in the forging process on metal streamline distribution is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of bearing preparation, and in particular to a method for rolling a tapered roller bearing with a complete conformal streamline raceway. Background Art

[0002] Bearings are core components of high-end equipment such as industrial mother machines, aircraft engines, and rail transportation, and directly affect the service performance and life of high-end equipment. Bearings are mainly composed of rings, rolling elements, and cages. Bearing rings are the core components that determine bearing performance, and raceway fatigue failure is the most common form of bearing failure. Therefore, it is crucial to improve the fatigue performance of bearing raceways.

[0003] With the rapid development of processing technology, existing manufacturing can guarantee the accuracy of bearings and achieve high-precision processing and manufacturing at the raceway. For example, Chinese patent CN111318630B discloses a near-net composite rolling forming method for the inner ring of a tapered roller bearing. However, the organizational state of the bearing is the key to determining fatigue performance. Existing manufacturing lacks control over the organizational 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 high-end equipment manufacturing. 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 of the tapered roller bearing along the raceway that follows the complete shape. Summary of the invention

[0004] In view of this, the present invention proposes a method for rolling a tapered roller bearing with a complete conformal streamline raceway, which is used to solve the problem that the current preparation process of the outer ring of the tapered roller 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 rolling a complete streamlined raceway of a tapered roller bearing, comprising the following steps: S1, designing a blank according to the size of the outer ring of the tapered roller bearing, a tapered surface is provided on the outer peripheral wall of one axial end of the blank, determining the size of the blank and the size of the blank to be cut, cutting the blank to obtain a material section, and controlling the height-to-diameter ratio of the bar to be small during the cutting process; S2, upsetting the bar 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, extruding and stamping the intermediate material to obtain a blank, and punching the blank to form a ring blank; S3, providing a driving roller and a core roller to form a fully closed hole, rolling the ring blank using the fully closed hole to achieve streamlined raceway forming to obtain a final forging, and controlling the rolling ratio to be large under the condition that the core roller can be placed in the fully closed hole.

[0006] On the basis of the above technical scheme, preferably, step S1 includes the following steps: S11, determining the axial height, bar volume and cutting 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 tapered surface of the blank according to the axial height and bar volume of the final forging; 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 in the process of determining the cutting 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, 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 a conical punch is used to punch to obtain a blank, an inner cavity with an inner cross-section of a conical cross-section is formed in the blank, and a skin is retained in the inner cavity of the blank; 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] 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 cone, D1 is the outer diameter of the billet, 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 calculated according to 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 upsetting ratio μ of the bar material 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 value range of the end diameter d1 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 method for rolling a tapered roller bearing with a complete conformal streamline raceway 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 conical surface. Then, by regulating the blank height, conical 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 whole process of forging the tapered roller bearing ring is realized.

[0027] (2) The present invention takes into account the influence of the blanking process on the subsequent blanking, designs the forming die cavity into a single cone, and designs the bar volume and blanking diameter so that the bar height-to-diameter ratio is as small as possible, thereby reducing the radial flow of the bearing ring metal at this stage; considers the influence 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 during the forging process on the metal streamline distribution.

[0028] (3) The present invention takes into account the effect 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, a reasonable rolling deformation amount is controlled 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 drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative work.

[0031] Figure 1 It is a schematic structural diagram of the outer ring forging of a tapered roller bearing of the present invention;

[0032] Figure 2 It is a schematic flow chart of step S2 of pre-forging a blank in a complete conformal streamline raceway rolling process of a tapered roller bearing outer ring forging of the present invention;

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

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

[0035] Figure 5 It is a schematic flow chart of step S3 of pre-forging a blank in a complete conformal streamline raceway rolling process of a tapered roller bearing outer ring forging of the present invention;

[0036] Figure 6 It is a 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 outer ring of the tapered roller bearing of the present invention.

[0038] In the figure: 1. extrusion preforming upper die; 2. extrusion preforming lower die; 3. conical punch; 4. blank; 5. 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 described embodiments 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 creative work are within the scope of protection of the present invention.

[0040] like Figure 1As shown, combined Figure 2 , Figure 3 and Figure 4 The present invention provides a method for rolling a tapered roller bearing with a complete conformal streamline raceway, comprising the following steps:

[0041] S1, design the blank 4 according to the size of the outer ring of the tapered roller bearing, and provide a conical surface on the outer peripheral wall of one axial end of the blank 4, determine the size of the blanked bar and the size of the blank 4, and obtain the material section by blanking, and control the height-to-diameter ratio of the bar to be small during the blanking process. Step S1 ensures the high-quality distribution of metal streamlines by precisely controlling the blanking process. By reasonably designing the volume and diameter of the bar, the metal radial flow problem caused by the bar diameter being too small and the radial deformation being too large can be avoided, thereby ensuring that the metal streamlines in subsequent processing are more ideal; reducing the height-to-diameter ratio can reduce the defects caused by uneven flow during the forming process of the outer ring of the bearing, and help achieve a better streamline distribution.

[0042] The purpose of setting the conical surface on the outer peripheral wall of the bottom end of the blank 4 is to improve the flow path of the metal during the forming process, especially for parts with complex geometric shapes such as the outer ring of a tapered roller bearing, the uniformity of metal flow is crucial. Through the design of the conical surface, the metal can be better guided when flowing at the bottom end of the blank, so that the metal flows in a predetermined direction during the plastic deformation process, thereby avoiding uneven flow and defects. The conical surface can help the metal flow along this surface by providing a gradually shrinking surface, reducing the non-uniformity of deformation. Normally, if the outer peripheral wall of the bottom end is a vertical surface, local accumulation may occur when the metal flows, resulting in poor flow, stress concentration or material shortage. The design of the conical surface provides a gradually changing inclined surface, so that the metal can gradually and evenly flow inward during deformation, improving the overall fluidity and filling properties. By setting the conical surface, the metal can be more evenly distributed in the mold during the deformation process, avoiding the phenomenon of local excessive deformation or insufficient metal flow. Especially for parts with complex geometric shapes, the conical surface can effectively reduce the accumulation of local materials and reduce the probability of defects such as cracks.

[0043] 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 stamping the intermediate material to obtain a blank 4, and punching the blank 4 to form a ring blank. By controlling the upsetting ratio, the radial flow of the metal can be effectively suppressed and the uneven distribution of the metal streamline can be prevented; the selection of the conical punch shape and the optimization of the stamping process are helpful to limit the radial flow of the metal, so that the deformation is concentrated on the inner diameter position of the ring blank, and the eddy current defects are avoided.

[0044] S3, a driving roller 6 and a core roller 7 are arranged to form a fully closed pass, and the ring blank is rolled using the fully closed pass to achieve the raceway streamline conformal forming to obtain the 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 pass. In the process of raceway formation, the rolling ratio needs to be strictly controlled to ensure the continuity and density of the streamline, and to ensure that the metal structure at the raceway is tight and uniform, which is conducive to improving the fatigue performance of the bearing; controlling the appropriate rolling ratio and conformal distribution of the metal streamline can optimize the strength, toughness and wear resistance of the bearing outer ring, thereby extending the service life of the bearing.

[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 according to the axial height and volume of the outer ring of the tapered roller bearing.

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

[0048] The cutting 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 according to the axial height of the final forging and the volume of the bar. 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 surface of the blank 4. The outer diameter of the outer ring of the tapered roller bearing is determined, that is, the outer diameter of the final forging or the outer diameter D1 of the blank 4 is determined, and 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, according to the cutting diameter of the bar, determine the cutting length and upsetting ratio of the bar and cut the bar to obtain the bar, and in the process of determining the cutting length of the bar, control the height-to-diameter ratio of the bar to be small. After the cutting diameter is calculated, according to the national standard GB702-72, select the largest possible standard bar diameter so that the height-to-diameter ratio of the bar is as small as possible, and finally obtain the corrected bar length and upsetting ratio during cutting. Bars with a relatively small height-to-diameter ratio can reduce the radial flow of metal during the forming process, avoiding problems such as uneven local streamlines and asymmetric deformation. Finally, the corrected cutting length and upsetting ratio are obtained, and then the material segment is cut according to the determined segment size and the segment is obtained.

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

[0058] 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. The purpose of controlling the upsetting ratio is to ensure that the blank 4 can be smoothly formed in the subsequent process through 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 effect 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 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 cone, D1 is the outer diameter of the blank 4, and D2 is the minimum outer diameter of the cone. Since the extrusion forming process is to extrude the roughened intermediate material into the blank 4, the intermediate material will be extruded from a smaller axial height to a larger height of the blank 4 during the process, so the maximum value of the intermediate material is not greater than 0.9 times the axial height of the blank 4; at the same time, during the forging or rolling forming process, the axial height of the blank (that is, the length of the blank) 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 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 will also cause insufficient metal flow in the mold, resulting in poor forming, so 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 cone 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 cone to ensure that the metal can evenly fill the mold; if the axial height of the cone is too large, it will increase the 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 cone is too small, the effect of the cone 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 cone to the axial height of the final forging can avoid the problem of uneven flow while ensuring the guiding effect of the cone, ensuring smooth flow and uniform deformation of the metal.

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

[0066]

[0067] Among them, the value range of n is 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 is a thin-walled structure, the minimum outer diameter of the cone surface may need to be smaller to avoid the metal from being unable to fill 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 due to excessive compression.

[0068] The outer diameter of the blank 4 is calculated based on the volume of the bar, the minimum outer diameter of the cone surface, the axial height of the cone 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. 1 , in step S22, when a conical punch 3 is used for reverse extrusion, in order to reduce the contact area between the conical punch 3 and the hard-to-deform area of ​​the blank 4 and to concentrate the deformation during the punching process on the inner diameter position of the inner cavity of the blank 4, a small-diameter conical 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 hole shape when the ring blank is subsequently rolled, so the value range of the end diameter d1 of the conical 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, a large rolling ratio should be used as much as possible under the condition that the core roller 7 can be smoothly placed in the hole. 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 conical punch 3.

[0078] exist Figure 2 In a preferred embodiment shown, the punch angle θ of the tapered punch 3 is 2° to 10°, and the punch angle θ of the tapered punch 3 is controlled to be small according to the axial height B of the final forging. Specifically, when the height B of the ring blank is large, the punch angle θ at the end of the tapered punch 3 should be appropriately selected to be small, and the edge of the end of the tapered punch 3 is rounded, with a fillet radius R = 0.15d1 + (1 to 2) mm, and the standard size is taken upward. Then, punching is performed to remove the skin 5, and a ring blank with a single cone at the end of the outer peripheral wall is obtained.

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

[0080] The present invention also 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-symmetrically 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, 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 skin 5 of the ring blank 4 is δ=9mm, and the maximum diameter of the core roller 7 is d0=45mm. The preparation process is implemented in the following steps:

[0082] (1) Determine the cutting size

[0083] According to the above technical solution, the end diameter of the conical punch 3 should be controlled to be: 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 bar material is obtained as follows:

[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=33~49.5mm, D2=(1~1.1)×123.19=123.19~135.51mm, take h=45mm, D2=125mm, get D1=139.61mm, then 134.08mm≤H1≤148.5mm, take H1=140mm, in order to reduce the bending degree of metal streamlines during forging, control the upsetting ratio of the material section to be, μ≤1.33, first take μ=1.3 and substitute it into the calculation formula of the blanking diameter D0, get D0=117.8mm, select the standard bar diameter according to the national standard GB702-72, and finally take D0=120mm, so as to get the blanking bar length H0=175.34mm, upsetting ratio μ=1.252. Then, blanking is carried out according to the bar size.

[0086] (2) Pre-forging

[0087] like Figure 2 As shown in FIG. 1 , the die forging is first performed on a press at a speed of 10 mm / s. After the forging, the blank is as shown in FIG. Figure 3 As shown. Then, the blank 4 is extruded on a press machine using an extrusion preforming upper die 1, an extrusion preforming lower die 2 and a conical punch 3, and the skin 5 is left at the bottom of the inner cavity of the blank. The end diameter d1 of the conical punch 3 is 48 mm, and the punch angle θ is selected to be 5°. The smaller punch end diameter and punch angle can reduce the contact area between the conical punch 3 and the difficult-to-deform area of ​​the blank 4, so that the deformation during the punching process is concentrated on the inner diameter position of the inner hole of the blank 4, and the metal streamline distribution will not be significantly changed during the punching process.

[0088] The end edge 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, and the standard value is R = 10 mm. The radius of the end edge of the conical punch 3 cannot be too small to avoid the difficulty of metal flow at the corner, severe deformation, and the 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 device includes a driving roller 6 and a core roller 7. The inner conical section ring blank is rolled on the ring rolling machine using the rolling pass. The near net shape of the raceway is achieved through the geometric design of the rolling pass and the control of the rolling deformation, 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 geometric shape is consistent with the cross-sectional shape of the forging 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 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 metallographic structure of the outer ring of the tapered roller bearing 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 protection scope 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 a 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 bar material to be cut and the size of the blank (4) and cutting the material to obtain a material section, and controlling the height-to-diameter ratio of the bar material to be small during the cutting 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 stamping the intermediate material to obtain a blank (4), and punching the blank (4) to form a ring blank; S3, a driving roller (6) and a core roller (7) are arranged to form a fully closed hole, and the ring blank is rolled using the fully closed hole to achieve rolling path streamline forming to obtain the 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 hole.

2. A method for rolling a tapered roller bearing with a complete conformal streamline raceway according to claim 1, characterized in that: The step S1 comprises 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 in the process of determining the cutting length of the bar, controlling the height-to-diameter ratio of the bar to be small.

3. A method for rolling a tapered roller bearing with a complete conformal streamline raceway according to claim 2, characterized in that: The step S2 comprises 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 arranged 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 a conical punch (3) is used to punch 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.

4. A method for rolling a tapered roller bearing with a complete conformal streamline raceway according to claim 3, characterized in that: In step S21, the range of the axial height H1 of the intermediate material is: Wherein, V0 is the volume of the bar, B is the axial height of the final forging, h is the axial height of the conical surface, D1 is the outer diameter of the blank (4), and D2 is the minimum outer diameter of the conical surface.

5. A method for rolling a tapered roller bearing with a complete conformal streamline raceway according to claim 4, characterized in that: 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, Among them, the value range of n is 1 to 1.1; The outer diameter of the blank (4) is calculated based on 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.

6. A method for rolling a tapered roller bearing with a complete conformal streamline raceway according to claim 3, characterized in that: In step S21, the upsetting ratio μ of the bar material satisfies, Wherein, H1 is the axial height of the intermediate material, and V0 is the volume of the bar material.

7. A method for rolling a tapered roller bearing with a complete conformal streamline raceway according to claim 3, characterized in that: In step S22, the value range of the end diameter d1 of the tapered punch (3) is, Wherein, 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.

8. A method for rolling a tapered roller bearing with a complete conformal streamline raceway according to claim 7, characterized in that: Determine the rolling ratio in step S3 for, Wherein, 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 conical punch (3).

9. A method for rolling a tapered roller bearing with a complete conformal streamline raceway according to claim 8, characterized in that: The punch angle θ of the tapered punch (3) is between 2° and 10°, and the punch angle θ of the tapered punch (3) is controlled to be as small as possible according to the axial height B of the final forging.

10. A method for rolling a tapered roller bearing with a complete conformal streamline raceway according to claim 8, characterized in that: When d1=d0, the minimum inner diameter D of the cavity is obtained. 1min .

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