Single row tapered roller bearing inner ring raceway shaping tool and forging process

Abstract

The application relates to a single-row tapered roller bearing inner ring raceway shaping tool and a forging process, and belongs to the bearing forging technical field.The single-row tapered roller bearing inner ring raceway shaping tool comprises a lower die base, an upper die base, a shaping lower die, an upper pressing die and a driving assembly, the shaping lower die is arranged on the lower die base, the shaping lower die is provided with a placing cavity for placing a bearing inner ring forging, the inner wall of the placing cavity is provided with a shaping conical surface, the shaping conical surface is used for matching a preset raceway conical surface of the bearing inner ring forging at a final forging temperature, the upper pressing die is arranged on the upper die base and is used for abutting against the upper end surface of the bearing inner ring forging, and the driving assembly is used for driving the upper die base to move with the upper pressing die.The application has the effects of reducing the size deviation of the high-temperature bearing inner ring forging caused by uneven cooling shrinkage, reducing the subsequent machining allowance, obtaining a relatively thick compact layer and prolonging the service life of the bearing inner ring.

Description

Technical Field

[0001] This application relates to the field of bearing forging technology, and in particular to a tooling and forging process for shaping the inner ring raceway of a single-row tapered roller bearing. Background Technology

[0002] Tapered roller bearings are a type of separable rolling bearing in which the inner ring raceway, outer ring raceway, and rolling elements are all tapered. These bearings are classified into different structural types, such as single-row, double-row, and four-row tapered roller bearings, according to the number of rows of rollers.

[0003] Currently, the inner rings of single-row tapered roller bearings are mainly formed by high-temperature forging. However, after the reaming process, the raceway tapered surface on the outer side of the high-temperature bearing inner ring forging is prone to uneven shrinkage and deformation during the cooling process. This makes it difficult to accurately control the machining allowance and dimensional tolerances, resulting in a shallow dense layer on the raceway tapered surface, which affects the dimensional accuracy of the bearing inner ring raceway tapered surface and the service life of the bearing inner ring. Summary of the Invention

[0004] To help reduce dimensional deviations in high-temperature bearing inner ring forgings caused by uneven cooling shrinkage, ensure the dimensional accuracy and form and position tolerances of the inner ring raceway tapered surface, reduce subsequent machining allowances, help obtain a thicker dense layer, and improve the service life of the bearing inner ring, this application provides a single-row tapered roller bearing inner ring raceway shaping tooling and forging process.

[0005] Firstly, this application provides a tooling for shaping the inner ring raceway of a single-row tapered roller bearing, which adopts the following technical solution: A tooling for shaping the inner ring raceway of a single-row tapered roller bearing, comprising: Lower mold base; The upper mold base is slidably disposed above the lower mold base in a vertical direction; A shaping lower die is disposed on the lower die base. The shaping lower die has a placement cavity for placing the bearing inner ring forging. The inner wall of the placement cavity has a shaping conical surface, which is used to match the preset raceway conical surface of the bearing inner ring forging at the final forging temperature. An upper die is disposed on the upper die base, and the upper die is used to abut against the upper end face of the bearing inner ring forging; A drive component is used to drive the upper mold base to move the upper pressure mold.

[0006] Preferably, the inner wall of the placement cavity has a lower limiting wall surface, the inner diameter of which is used to match the preset minimum outer diameter of the bearing inner ring forging at the final forging temperature, and the lower limiting wall surface is located below the forming cone surface.

[0007] Preferably, the inner wall of the placement cavity has an upper limit wall surface, the inner diameter of which is greater than the preset maximum outer diameter of the bearing inner ring forging at the final forging temperature, the upper limit wall surface is located above the forming cone surface, and the outer diameter of the upper die is less than or equal to the inner diameter of the upper limit wall surface.

[0008] Preferably, the lower die base is provided with a stripper rod that slides vertically through it, and the stripper rod slides into the placement cavity. The upper die base is provided with a transmission assembly, which is used to drive the stripper rod to move upward during the upward movement of the upper die base, so as to push the shaped bearing inner ring forging out of the placement cavity.

[0009] Preferably, the transmission assembly includes a pull rod and a base plate. The pull rod is connected to the upper mold base, and the base plate is connected to the pull rod. The base plate is located below the unloading rod and is used to abut against the upward movement of the unloading rod.

[0010] Preferably, a support base for supporting the bearing inner ring forging 4 is slidably disposed in the placement cavity. The unloading rod is located below the support base. When the support base abuts against the bottom wall of the placement cavity, and the forming cone surface of the forming lower die abuts against the raceway cone surface of the bearing inner ring forging on the support base, the lower end of the pull rod is higher than the upper surface of the base plate. A pressure relief hole is provided on the support base.

[0011] Preferably, the support base has a groove, the pressure relief hole is located on the bottom wall of the groove, and the inner diameter of the groove is greater than or equal to the inner diameter of the bearing inner ring forging.

[0012] Preferably, the unloading rod is provided with an anti-detachment block, and the lower mold base is provided with a snap-fit ​​groove that engages with the anti-detachment block. The depth of the snap-fit ​​groove is greater than the thickness of the anti-detachment block. The anti-detachment block is aligned with the pressure relief hole, and the cross-sectional area of ​​the anti-detachment block is greater than the cross-sectional area of ​​the pressure relief hole.

[0013] Preferably, the lower mold base has an installation cavity, the shaping lower mold is located in the installation cavity, a prestressed mold is provided in the installation cavity, the prestressed mold is sleeved on the outside of the shaping lower mold, the inner circumference of the prestressed mold has a limiting inner cone surface, the outer circumference of the shaping lower mold has a limiting outer cone surface, the limiting inner cone surface is used to abut against the limiting outer cone surface, the lower mold base is detachably provided with a cover plate, the prestressed mold is located in the cover plate, the inner circumference of the cover plate has a pressing inner cone surface, the outer circumference of the prestressed mold has a pressing outer cone surface, the pressing inner cone surface is used to abut against the pressing outer cone surface.

[0014] Secondly, this application provides a forging process for the inner ring of a single-row tapered roller bearing, employing the following technical solution: A forging process for the inner ring of a single-row tapered roller bearing, using the aforementioned single-row tapered roller bearing inner ring raceway shaping fixture, includes the following steps: The billet is prepared by heating the bar stock to the forging temperature and then hot shearing it. Upsetting: The billet is upset to a ratio of 3-5. Punching involves using a punching punch to create blind holes in the upset blank, with a punching deformation of 1.5. Piercing is used to open up the blind holes in the blank after punching. Hole enlargement is performed by using the rolling disc on a hole enlarger to enlarge the hole in the pierced billet. The size of the raceway cone surface of the enlarged billet is 0.5mm-2mm larger than the size of the shaped cone surface. In the shaping process, the expanded bearing inner ring forging is placed into the placement cavity of the shaping lower die. Then, the drive assembly is activated, which drives the upper die holder to move the upper pressure die downward, so that the upper pressure die abuts against the upper end face of the bearing inner ring forging. Under the vertical pressure of the upper pressure die, the raceway tapered surface of the outer circumference of the bearing inner ring forging is driven to fit with the shaping tapered surface of the inner circumference of the shaping lower die, thus performing forced precision shaping. Forging cooling is performed by using rapid cooling in the early stage and air cooling in the later stage to cool the forgings after shaping. annealing.

[0015] In summary, this application includes the following beneficial technical effects: 1. During operation, the bearing inner ring forging at the preset final forging temperature after hole expansion is placed into the placement cavity of the forming lower die. Then, the drive assembly is activated, which drives the upper die holder to move the upper pressure die downward, so that the upper pressure die abuts against the upper end face of the bearing inner ring forging. Under the vertical pressure of the upper pressure die, the raceway cone surface of the outer circumference of the bearing inner ring forging is driven to fit against the forming cone surface of the inner circumference of the forming lower die, thereby performing forced precision forming. Since the cone angle of the forming cone surface is consistent with the preset raceway cone angle at the final forging temperature of the bearing inner ring forging, and the entire forming lower die is at room temperature, the forming cone surface can quickly cool down locally during the forming process of the high-temperature bearing inner ring forging, reducing the dimensional deviation of the forging caused by uneven cooling shrinkage, stabilizing the size and shape of the bearing inner ring forging after forming, thus helping to ensure the dimensional accuracy and form and position tolerance of the raceway cone surface, reducing the subsequent machining allowance, helping to obtain a thicker dense layer, and effectively improving the fatigue life and operational reliability of the bearing product. 2. By adopting a large upsetting ratio, it helps to meet the material deformation requirements, so that the looseness, micropores and shrinkage cavities inside the billet are welded together and densified during the deformation process, thereby improving the density of the material. The post-forging cooling method of rapid cooling in the early stage and air cooling in the later stage helps to ensure the uniformity of the internal structure and improve the service life of the product. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the tooling in the initial state in the embodiments of this application.

[0017] Figure 2This is a partial structural diagram of the tooling in its initial state in an embodiment of this application.

[0018] Figure 3 This is a schematic diagram of the lower mold base in its initial state in an embodiment of this application.

[0019] Figure 4 This is a partial exploded view of an embodiment of this application.

[0020] Figure 5 This is a partial structural diagram of the tooling in the shaping state in the embodiments of this application.

[0021] Explanation of reference numerals in the attached drawings: 1. Lower mold base; 2. Upper mold base; 3. Shaping lower mold; 31. Limiting outer conical surface; 4. Bearing inner ring forging; 5. Placement cavity; 6. Shaping conical surface; 7. Upper pressure mold; 8. Lower limiting wall surface; 9. Upper limiting wall surface; 10. Unloading rod; 11. Tie rod; 12. Base plate; 13. Support base; 14. Pressure relief hole; 15. Groove; 16. Anti-detachment block; 17. Snap-fit ​​groove; 18. Mounting cavity; 19. Prestressed mold; 191. Limiting inner conical surface; 192. Pressing outer conical surface; 20. Cover plate; 201. Pressing inner conical surface; 21. Mold frame. Detailed Implementation

[0022] The following combination Figures 1-5 This application will be described in further detail.

[0023] This application discloses a tooling for shaping the inner ring raceway of a single-row tapered roller bearing. (Refer to...) Figure 1 and Figure 2 The single-row tapered roller bearing inner ring raceway shaping fixture includes a mold frame 21, a lower mold base 1, an upper mold base 2, a shaping lower mold 3, an upper pressure mold 7, and a drive assembly. The mold frame 21 serves as the bottom support base of the shaping fixture. The lower mold base 1 is fixedly installed on the mold frame 21 by welding or bolting. The upper mold base 2 is slidably positioned above the lower mold base 1 in the vertical direction. Specifically, the upper mold base 2 can be slidably positioned on the mold frame 21 in the vertical direction by the cooperation of a slider and a guide rail, or it can be slidably positioned above the lower mold base 1 by fixing a guide post on the lower mold base 1 and opening a guide hole on the upper mold base 2 that slides with the guide post. No limitation is made here.

[0024] Reference Figure 2 and Figure 3 The lower die base 1 has an installation cavity 18 with a circular cross-section. The shaping lower die 3 is installed in the installation cavity 18 of the lower die base 1. The shaping lower die 3 is annular and has a placement cavity 5 at its center for placing the bearing inner ring forging 4.

[0025] Reference Figure 3 and Figure 4Furthermore, the inner wall of the placement cavity 5 has a shaped conical surface 6, which is a conical annular structure. Its cone angle and cone surface profile match the preset raceway cone surface of the bearing inner ring forging 4 at the final forging temperature. The bearing inner ring forging 4 is placed into the placement cavity 5 at the final forging temperature, at which time the forging temperature is usually between 700°C and 900°C, and the material still has good plasticity.

[0026] Reference Figure 2 The upper die 7 is bolted to the upper die base 2 and moves vertically together with the upper die base 2. The upper die 7 is cylindrical and abuts against the upper end face of the bearing inner ring forging 4. The drive assembly is mounted on the die frame 21 or the lower die base 1 and drives the upper die base 2 to move the upper die 7. In this embodiment, the drive assembly is mounted on the die frame 21. Specifically, the drive assembly can be a hydraulic cylinder or a servo electric cylinder, with its output end fixedly connected to the top surface of the upper die base 2. The extension and retraction of the drive assembly drives the upper die base 2 to move up and down vertically. In other embodiments, the drive assembly can also be a cylinder, an electric push rod, or other driving method.

[0027] During operation, the bearing inner ring forging 4, after reaming and final forging at the preset temperature, is placed into the placement cavity 5 of the shaping lower die 3. Then, the drive assembly is activated, driving the upper die holder 2 to move the upper pressure die 7 downwards, causing the upper pressure die 7 to abut against the upper end face of the bearing inner ring forging 4. Under the vertical pressure of the upper pressure die 7, the raceway cone surface of the outer circumference of the bearing inner ring forging 4 is forced to fit against the shaping cone surface 6 of the inner circumference of the shaping lower die 3, thus performing forced precision shaping. Because the cone angle of the shaping cone surface 6 is equal to the preset raceway cone angle at the final forging temperature of the bearing inner ring forging 4... Furthermore, since the entire lower die 3 is at room temperature, rapid local cooling is achieved during the forming process where the forming conical surface 6 abuts against the high-temperature bearing inner ring forging 4. This helps reduce dimensional deviations caused by uneven cooling and shrinkage of the raceway conical surface of the bearing inner ring forging 4, thereby stabilizing the dimensions and shape of the formed bearing inner ring forging 4. This helps ensure the dimensional accuracy and geometric tolerances of the raceway conical surface, reduces subsequent machining allowances, and facilitates the formation of a thicker, denser layer. It also ensures the geometric accuracy of the raceway conical surface on the bearing inner ring forging 4, effectively improving the fatigue life and operational reliability of the bearing product. Simultaneously, using the forming tooling of this application helps ensure product dimensional consistency in mass production, reduces rework and scrap, and the rapid forming process improves overall production efficiency.

[0028] The dense layer refers to the distance between the raceway cone surface and the displayed forging flow lines; the greater the distance, the thicker the material in that part, the better its performance, and the lower the possibility of failure.

[0029] Reference Figure 3 and Figure 4To facilitate the positioning of the bearing inner ring forging 4, the inner wall of the placement cavity 5 has a lower limiting wall surface 8, which is located below the forming conical surface 6. The inner diameter of the lower limiting wall surface 8 matches the preset minimum outer diameter of the bearing inner ring forging 4 at the final forging temperature. Furthermore, the inner diameter of the lower limiting wall surface 8 is equal to the minimum diameter of the forming conical surface 6, so that the lower limiting wall surface 8 connects with the lower side of the forming conical surface 6. By making the outer circumferential surface of the smaller end of the bearing inner ring forging 4 in close contact with the lower limiting wall surface 8, the smaller end of the bearing inner ring forging 4 can be effectively radially limited during the forming process.

[0030] Reference Figure 3 and Figure 4 To prevent interference during the forming process of the bearing inner ring forging 4, the inner wall of the placement cavity 5 also has an upper limit wall surface 9. The upper limit wall surface 9 is located above the forming conical surface 6. The inner diameter of the upper limit wall surface 9 is larger than the preset maximum outer diameter of the bearing inner ring forging 4 at the final forging temperature. Furthermore, the inner diameter of the upper limit wall surface 9 is larger than the maximum inner diameter of the forming conical surface 6, so that an appropriate gap is left between the outer circumferential surface of the large end of the bearing inner ring forging 4 and the upper limit wall surface 9, which facilitates the insertion and removal of the forging. In other embodiments, the inner diameter of the upper limit wall surface 9 can also be designed to match the preset maximum outer diameter of the bearing inner ring forging 4 at the final forging temperature.

[0031] Reference Figure 2 and Figure 4 The outer diameter of the upper mold 7 is less than or equal to the inner diameter of the upper limit wall 9, so that the upper mold 7 can smoothly enter the placement cavity 5 without interfering with the upper limit wall 9.

[0032] Reference Figure 2 and Figure 3 To facilitate demolding of the shaped bearing inner ring forging 4, a stripper rod 10 is slidably installed on the lower mold base 1 along the vertical direction. The stripper rod 10 is a cylindrical rod structure, with its lower end located outside the lower mold base 1 and its upper end sliding into the placement cavity 5. The stripper rod 10 is located at the center of the shaping lower mold 3. A transmission assembly is provided on the upper mold base 2. The transmission assembly is used to drive the stripper rod 10 upward during the upward movement of the upper mold base 2, so as to push the shaped bearing inner ring forging 4 out of the placement cavity 5.

[0033] Reference Figure 2 and Figure 3To facilitate the upward movement of the unloading rod 10 during the rising of the upper mold base 2, the transmission assembly includes pull rods 11 and a base plate 12. Multiple pull rods 11 are evenly spaced along the circumference of the upper mold base 2. The pull rods 11 slide vertically through the mold frame 21, and correspondingly, the mold frame 21 has through holes for the pull rods 11 to slide through. The upper end of each pull rod 11 is welded to the upper mold base 2 or detachably fixed via a threaded connection and nut. The base plate 12 is fixedly connected to the lower ends of the multiple pull rods 11. Specifically, the base plate 12 and the pull rods 11 can be fixedly connected by welding or locking nuts. The base plate 12 is located directly below the unloading rod 10 and has a disc-shaped or square plate structure. When the upper mold base 2 rises, the pull rods 11 drive the base plate 12 to rise synchronously, and the upper surface of the base plate 12 is used to abut against the unloading rod 10 as it moves upward.

[0034] After the molding is completed, the upper mold base 2 moves the base plate 12 upward through multiple tie rods 11, which helps the base plate 12 to abut against the unloading rod 10, so that the unloading rod 10 pushes out the bearing inner ring forging 4 in the placement cavity 5, which facilitates demolding and material removal.

[0035] Reference Figure 2 , Figure 3 and Figure 4 A support base 13 is slidably disposed within the placement cavity 5. Specifically, the support base 13 has a circular cross-section, and its outer wall is clearance-fitted with the lower limit wall 8 within the placement cavity 5. The support base 13 supports the bearing inner ring forging 4. A discharge rod 10 is located directly below the support base 13, and an anti-detachment block 16 is welded to its upper end. The lower end face of the support base 13 abuts against the upper end face of the anti-detachment block 16. When the discharge rod 10 moves upward, the anti-detachment block 16 pushes the support base 13, along with the bearing inner ring forging 4 on it, upward together.

[0036] Reference Figure 3 and Figure 5 The lower mold base 1 has a locking groove 17 that engages with the anti-detachment block 16. The locking groove 17 is a circular groove structure with an inner diameter slightly larger than the outer diameter of the anti-detachment block 16. When the support base 13 abuts against the bottom wall of the placement cavity 5, and the shaping cone surface 6 of the shaping lower mold 3 abuts against the raceway cone surface of the bearing inner ring forging 4 on the support base 13, the lower end of the pull rod 11 is higher than the upper surface of the base plate 12. This prevents the base plate 12 from rigidly blocking the downward movement of the unloading rod 10, which helps ensure that the upper pressure mold 7 can press the bearing inner ring forging 4 into place. At the same time, this height difference design also ensures that when the upper mold base 2 moves upward, the base plate 12 can abut against the unloading rod 10 at an appropriate position to achieve a reliable demolding action.

[0037] Reference Figure 3The upper surface of the support base 13 is provided with a groove 15, the cross-section of the groove 15 is circular, and the inner diameter of the groove 15 is greater than or equal to the inner diameter of the bearing inner ring forging 4; furthermore, the bottom wall of the groove 15 is provided with a pressure relief hole 14, which penetrates the support base 13 in the vertical direction, so that gas can be discharged through the pressure relief hole 14 during the shaping process.

[0038] Reference Figure 3 The anti-detachment block 16 is aligned with the pressure relief hole 14, and the cross-sectional area of ​​the anti-detachment block 16 is larger than that of the pressure relief hole 14. The depth of the locking groove 17 is greater than the thickness of the anti-detachment block 16. This design ensures that the unloading rod 10 will not detach from the placement cavity 5 during reciprocating motion. At the same time, during the molding process, since there are gaps between the anti-detachment block 16 and the bottom wall of the locking groove 17, and between the unloading rod 10 and the lower mold base 1, the anti-detachment block 16 will not block the exhaust channel of the pressure relief hole 14.

[0039] Reference Figure 3 The inner diameter of the mounting cavity 18 is larger than the outer diameter of the lower mold 3. To facilitate the fixing of the lower mold 3, a prestressed mold 19 is provided in the mounting cavity 18. The prestressed mold 19 has a circular sleeve structure and is sleeved on the lower mold 3. The inner diameter of the prestressed mold 19 matches the outer diameter of the lower mold 3, and the outer diameter of the prestressed mold 19 matches the inner diameter of the mounting cavity 18.

[0040] Reference Figure 3 and Figure 4 Furthermore, the upper inner ring surface of the prestressed mold 19 has a limiting inner conical surface 191, and the upper outer circumferential surface of the shaping lower mold 3 has a limiting outer conical surface 31. Both the limiting inner conical surface 191 and the limiting outer conical surface 31 are conical mating surfaces, with the limiting inner conical surface 191 abutting against the limiting outer conical surface 31. When the shaping lower mold 3 is subjected to radial expansion force from the bearing inner ring forging 4, the tight fit between the limiting outer conical surface 31 and the limiting inner conical surface 191 generates a radial constraint force on the shaping lower mold 3.

[0041] Reference Figure 3 and Figure 4 To facilitate the fixing of the prestressed mold 19, a cover plate 20 is detachably provided on the lower mold base 1. Specifically, the cover plate 20 is annular and can be detachably installed on the top surface of the lower mold base 1 using fasteners such as bolts or screws. The prestressed mold 19 is located inside the cover plate 20. The inner circumferential surface of the cover plate 20 has a pressing inner conical surface 201, which is a conical annular structure. The upper outer circumferential surface of the prestressed mold 19 has a pressing outer conical surface 192. The pressing inner conical surface 201 is used to abut against the pressing outer conical surface 192. Furthermore, the diameters of the pressing inner conical surface 201, the pressing outer conical surface 192, the limiting inner conical surface 191, and the limiting outer conical surface 31 all increase from top to bottom to achieve a conical pressing effect.

[0042] When assembling the tooling, first place the shaping lower mold 3 in the mounting cavity 18, then put the prestressing mold 19 on the outside of the shaping lower mold 3. At this time, the outer wall of the prestressing mold 19 abuts against the inner wall of the placement cavity 5. Under the action of external force, the limiting inner cone surface 191 of the prestressing mold 19 abuts against the limiting outer cone surface 31 of the outer circumference of the shaping lower mold 3. Then, fix the cover plate 20 to the upper surface of the lower mold base 1 by bolts or screws, so that the pressing inner cone surface 201 of the cover plate 20 matches the pressing outer cone surface 192 of the prestressing mold 19, thereby locking the shaping lower mold 3 and the prestressing mold 19. The detachable design of the cover plate 20 facilitates the replacement and maintenance of the shaping lower mold 3 and the prestressing mold 19.

[0043] The implementation principle of this application embodiment is as follows: When the shaping tooling is in the initial state, the driving component moves the upper mold base 2 and the upper pressure mold 7 to a position away from the lower mold base 1. At this time, the bottom plate 12 abuts against the bottom of the unloading rod 10, the anti-detachment block 16 disengages from the snap-fit ​​groove 17, and the support base 13 disengages from the bottom wall of the placement cavity 5.

[0044] During operation, the bearing inner ring forging 4, after reaming and final forging at the preset temperature, is placed on the support base 13. Then, the drive assembly is activated, driving the upper die holder 2 to move the upper pressure die 7 downwards. At this time, the contact force between the base plate 12 and the unloading rod 10 decreases. Under the gravity of the unloading rod 10, the anti-detachment block 16, the support base 13, and the bearing inner ring forging 4, the unloading rod 10, the anti-detachment block 16, the support base 13, and the bearing inner ring forging 4 move downwards synchronously until the anti-detachment block 16 moves into the locking groove 17, and the support base 13 abuts against the bottom wall of the placement cavity 5. At this point, the support base 13 and the unloading rod 10 are in position. Then, the drive assembly continues to drive the upper die holder 2 and the upper pressure die 7 downwards, causing the base plate 12 to detach from the unloading rod 10. The upper pressure die 7 abuts against the upper end face of the bearing inner ring forging 4. Under pressure, the raceway cone surface on the outer circumference of the bearing inner ring forging 4 is forced to fit against the shaping cone surface 6 on the inner circumference of the shaping die 3, thereby performing forced precision shaping. Since the cone angle of the shaping cone surface 6 is consistent with the preset raceway cone angle at the final forging temperature of the bearing inner ring forging 4, and the entire shaping die 3 is at room temperature, the raceway cone surface of the high-temperature bearing inner ring forging 4 can be rapidly cooled during the shaping process of the shaping cone surface 6 against the high-temperature bearing inner ring forging 4. This helps to reduce dimensional deviations caused by uneven cooling and shrinkage of the raceway cone surface of the bearing inner ring forging 4, ensuring the dimensional accuracy and form and position tolerances of the raceway cone surface, reducing subsequent machining allowances, and helping to obtain a thicker, denser layer. This ensures the geometric accuracy of the raceway cone surface on the bearing inner ring forging 4, effectively improving the fatigue life and operational reliability of the bearing product. Simultaneously, using the shaping tooling of this application helps to ensure product dimensional consistency in mass production, reducing rework and scrap, and the shaping process is fast, improving overall production efficiency.

[0045] After the shaping is completed, the drive assembly drives the upper mold base 2 and the upper pressure mold 7 to move upward. The upper mold base 2 drives the base plate 12 to move upward through the pull rod 11, so that the upper pressure mold 7 is separated from the bearing inner ring forging 4. As the base plate 12 continues to move upward, the base plate 12 abuts against the lower end face of the unloading rod 10 and pushes the unloading rod 10 to move upward. The anti-detachment block 16 on the unloading rod 10 pushes the support base 13 together with the bearing inner ring forging 4 on it to move upward, pushing the bearing inner ring forging 4 out of the placement cavity 5 to achieve demolding. Then the operator or the material handling mechanism can take out the bearing inner ring forging 4 to facilitate the next shaping cycle.

[0046] This application also discloses a forging process for the inner ring of a single-row tapered roller bearing. The forging process for the inner ring of a single-row tapered roller bearing utilizes the aforementioned single-row tapered roller bearing inner ring raceway shaping fixture and includes the following steps.

[0047] Step 1: Material preparation. The bar stock is heated to the forging temperature and then hot-sheared to obtain the billet.

[0048] Specifically, multiple bars are hoisted onto a rack and fed into a medium-frequency induction furnace for medium-frequency heating, gradually increasing the temperature from room temperature to a preset forging temperature. Then, a punch press with cutting tools is used to hot-shear the heated bars to the required process length, yielding a billet. In this embodiment, the height-to-diameter ratio of the billet is 3.

[0049] Step 2: Upsetting. Upset the billet to a ratio of 3-5.

[0050] Specifically, the hot-sheared billet is placed in the upsetting station of a press for upsetting. To ensure the degree of material deformation, the upsetting ratio is 3-5. The upsetting ratio refers to the ratio of the height before upsetting to the height after upsetting, or equivalently, the ratio of the cross-sectional area after upsetting to the cross-sectional area before upsetting. In this embodiment, a preferred upsetting ratio is 3.5. A large upsetting ratio helps to satisfy the material deformation requirements, causing the looseness, micropores, and shrinkage cavities inside the billet to be welded together and densified during the deformation process, thereby improving the density of the material and laying the foundation for obtaining a thicker, denser layer.

[0051] Step 3: Punching. Use a punching punch to punch blind holes in the upset billet. The punching deformation is 1.5.

[0052] Specifically, the upset billet is placed into a punching die, and a punching punch is used to punch blind holes in the billet. The punching is performed using reverse extrusion, and the punch is a large-tapered punch with a taper angle of 18°-30°. During this process, the material deforms in the reverse direction. This reverse extrusion deformation causes the upset billet to extend axially to a certain extent, with a deformation amount of 1.5. The deformation amount refers to the ratio of the height of the billet after punching to the height of the billet before punching.

[0053] Step 4: Punching, to open up the blind holes in the blank after punching.

[0054] After punching, the blank is punched through from the back of the blind hole using a piercing punch, ensuring that the mandrel of the subsequent reamer can be smoothly inserted into the blank.

[0055] Step 5: Hole enlargement. The blank after piercing is enlarged using the rolling disc on the hole enlarger. The size of the raceway cone surface of the blank after hole enlargement is 0.5mm-2mm larger than the size of the shaped cone surface.

[0056] Furthermore, the shape of the working surface of the rolling disc is consistent with the pre-set final forging shape, which helps to ensure that the forging flow line is consistent with the product raceway shape; in the embodiment of this application, the size of the raceway cone surface of the billet after hole expansion is 1mm-2mm larger than the size of the forming cone surface to ensure that the dense layer is deep enough.

[0057] Step 6: Shaping. Place the bearing inner ring forging 4, after reaming and final forging at the preset temperature, on the support base 13. Then, start the drive assembly. The drive assembly drives the upper die base 2 to move the upper pressure die 7 downward. Under the gravity of the unloading rod 10, the anti-detachment block 16, the support base 13, and the bearing inner ring forging 4, the unloading rod 10, the anti-detachment block 16, the support base 13, and the bearing inner ring forging 4 move downward synchronously until the anti-detachment block 16 moves into the locking groove 17. The support base 13 abuts against the bottom wall of the placement cavity 5. At this time, the support base 13 and the unloading rod 10 are in place. Then, the drive assembly continues to drive the upper mold base 2 and the upper pressure mold 7 to move down, so that the bottom plate 12 is separated from the unloading rod 10. The upper pressure mold 7 abuts against the upper end face of the bearing inner ring forging 4. Under the vertical pressure of the upper pressure mold 7, the raceway cone surface of the outer circumference of the bearing inner ring forging 4 is driven to fit with the shaping cone surface 6 of the inner circumference of the shaping lower mold 3, so as to perform forced precision shaping.

[0058] Step 7: Post-forging cooling. The forging is cooled by rapid cooling in the early stage and air cooling in the later stage.

[0059] Specifically, the initial rapid cooling followed by subsequent air cooling method involves simultaneously cooling the forging with air cooling and water mist cooling. After the forging cools to a first preset cooling temperature, air cooling is then used to further cool it to a second preset cooling temperature, followed by natural air cooling. The first and second preset cooling temperatures are set as needed. This continuous and rapid cooling method helps to ensure a uniform raceway structure free of network carbides, thus meeting the required internal microstructure.

[0060] Step 8: Annealing.

[0061] Continuous spheroidizing annealing is performed on the forgings after cooling to obtain a uniform spheroidized structure.

[0062] In addition, to ensure stable dimensional stability, this embodiment also controls the temperature of each process during forging by controlling the billet preparation cycle. Specifically, in this embodiment, the upsetting, punching, and piercing steps each take about 3 seconds, the reaming takes about 5 seconds, and after reaming, the transfer time from the reamer to the raceway shaping fixture is about 2 seconds. By matching the time of each process and coordinating the production line cycle, the final forging temperature can be controlled, which helps to ensure the dimensional stability of the finished product.

[0063] The implementation principle of the forging process in this application embodiment is as follows: by adopting a large upsetting ratio, it helps to meet the material deformation, so that the porosity, micropores and shrinkage cavities inside the billet are welded together and densified during the deformation process, thereby improving the density of the material; the finishing of the inner ring raceway shaping tool ensures the shape and position dimensions of the raceway, while reducing the machining allowance, which helps to obtain a thicker dense layer; and the post-forging cooling method of rapid cooling in the early stage and air cooling in the later stage makes the raceway structure more uniform, ensuring that the internal structure transformation meets the requirements.

[0064] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A tooling for shaping the raceway of the inner ring of a single-row tapered roller bearing, characterized in that, include: Lower mold base (1); The upper mold base (2) is slidably disposed above the lower mold base (1) in the vertical direction; A shaping lower die (3) is provided on the lower die base (1). The shaping lower die (3) has a placement cavity (5) for placing the bearing inner ring forging (4). The inner wall of the placement cavity (5) has a shaping cone surface (6). The shaping cone surface (6) is used to match the preset raceway cone surface at the final forging temperature of the bearing inner ring forging (4). An upper die (7) is disposed on the upper die base (2), and the upper die (7) is used to abut against the upper end face of the bearing inner ring forging (4); A drive assembly is used to drive the upper mold base (2) to move the upper pressure mold (7).

2. The single-row tapered roller bearing inner ring raceway shaping fixture according to claim 1, characterized in that, The inner wall of the placement cavity (5) has a lower limiting wall surface (8), the inner diameter of which is used to match the preset minimum outer diameter of the bearing inner ring forging (4) at the final forging temperature, and the lower limiting wall surface (8) is located below the forming cone surface (6).

3. The single-row tapered roller bearing inner ring raceway shaping fixture according to claim 1, characterized in that, The inner wall of the placement cavity (5) has an upper limit wall surface (9), the inner diameter of which is greater than the preset maximum outer diameter of the bearing inner ring forging (4) at the final forging temperature. The upper limit wall surface (9) is located above the forming cone surface (6), and the outer diameter of the upper die (7) is less than or equal to the inner diameter of the upper limit wall surface (9).

4. The single-row tapered roller bearing inner ring raceway shaping fixture according to claim 1, characterized in that, The lower mold base (1) is slidably provided with a stripper rod (10) in the vertical direction. The stripper rod (10) slides into the placement cavity (5). The upper mold base (2) is provided with a transmission assembly. The transmission assembly is used to drive the stripper rod (10) to move upward during the upward movement of the upper mold base (2) so as to push the shaped bearing inner ring forging (4) out of the placement cavity (5).

5. The single-row tapered roller bearing inner ring raceway shaping fixture according to claim 4, characterized in that, The transmission assembly includes a pull rod (11) and a base plate (12). The pull rod (11) is connected to the upper mold base (2), and the base plate (12) is connected to the pull rod (11). The base plate (12) is located below the unloading rod (10) and is used to abut against the unloading rod (10) as it moves upward.

6. The single-row tapered roller bearing inner ring raceway shaping fixture according to claim 5, characterized in that, The placement cavity (5) is slidably provided with a support base (13) for supporting the bearing inner ring forging 4. The unloading rod (10) is located below the support base (13). When the support base (13) abuts against the bottom wall of the placement cavity (5), and the shaping cone surface (6) of the shaping lower die (3) abuts against the raceway cone surface of the bearing inner ring forging (4) on the support base (13), the lower end of the pull rod (11) is higher than the upper surface of the base plate (12). The support base (13) is provided with a pressure relief hole (14).

7. The single-row tapered roller bearing inner ring raceway shaping fixture according to claim 6, characterized in that, The support base (13) has a groove (15) and the pressure relief hole (14) is located on the bottom wall of the groove (15). The inner diameter of the groove (15) is greater than or equal to the inner diameter of the bearing inner ring forging (4).

8. A single-row tapered roller bearing inner ring raceway shaping fixture according to claim 6, characterized in that, The unloading rod (10) is provided with an anti-detachment block (16), and the lower mold base (1) is provided with a snap-fit ​​groove (17) that engages with the anti-detachment block (16). The depth of the snap-fit ​​groove (17) is greater than the thickness of the anti-detachment block (16). The anti-detachment block (16) is aligned with the pressure relief hole (14), and the cross-sectional area of ​​the anti-detachment block (16) is greater than the cross-sectional area of ​​the pressure relief hole (14).

9. A single-row tapered roller bearing inner ring raceway shaping fixture according to any one of claims 1-8, characterized in that, The lower mold base (1) has an installation cavity (18), the shaping lower mold (3) is located in the installation cavity (18), and a prestressed mold (19) is provided in the installation cavity (18). The prestressed mold (19) is sleeved on the outside of the shaping lower mold (3). The inner circumference of the prestressed mold (19) has a limiting inner cone surface (191), and the outer circumference of the shaping lower mold (3) has a limiting outer cone surface (31). The surface (191) is used to abut against the limiting outer cone surface (31). The lower mold base (1) is detachably provided with a cover plate (20). The prestressed mold (19) is located inside the cover plate (20). The inner circumferential surface of the cover plate (20) has a pressing inner cone surface (201). The outer circumferential surface of the prestressed mold (19) has a pressing outer cone surface (192). The pressing inner cone surface (201) is used to abut against the pressing outer cone surface (192).

10. A forging process for the inner ring of a single-row tapered roller bearing, using the single-row tapered roller bearing inner ring raceway shaping tooling as described in any one of claims 1-9, characterized in that, Includes the following steps: The billet is prepared by heating the bar stock to the forging temperature and then hot shearing it to obtain the billet. Upsetting: The billet is upset to a ratio of 3-5. Punching involves using a punching punch to create blind holes in the upset blank, with a punching deformation of 1.

5. Piercing is used to open up the blind holes in the blank after punching. Hole enlargement is performed by using the rolling disc on a hole enlarger to enlarge the hole in the pierced billet. The size of the raceway cone surface of the enlarged billet is 0.5mm-2mm larger than the size of the shaped cone surface. For shaping, the bearing inner ring forging after hole expansion is placed in the placement cavity (5) of the shaping lower die (3). Then, the drive assembly is started. The drive assembly drives the upper die seat (2) to drive the upper pressure die (7) to move downward, so that the upper pressure die (7) abuts against the upper end face of the bearing inner ring forging. Under the vertical pressure of the upper pressure die (7), the raceway cone surface of the outer circumference of the bearing inner ring forging is driven to fit with the shaping cone surface (6) of the inner circumference of the shaping lower die (3) for forced precision shaping. Forging cooling is performed by using rapid cooling in the early stage and air cooling in the later stage to cool the forgings after shaping. annealing.

Images