Single-row conical bearing inner sleeve forging machining process and profiling tool

Abstract

The invention provides a single-row conical bearing inner sleeve forging machining process and a profiling tool. The process comprises the following steps of incoming material inspection, saw cutting and blanking, heating, upsetting material in-mold forming, in-mold blind hole punching, material core removing, end face flattening, demolding, ring rolling forming, spray cooling and spheroidizing annealing. The bearing inner sleeve forging profiling tool comprises a blank making die, a rolling wheel and a limiting roller. The blank making die comprises a material upsetting die and a punch, and a middle blank with the similar shape is obtained through the blank making die; the outer diameter of the rolling wheel and the outer diameter of the limiting roller are both provided with rolling parts similar to the outer diameter of the forge piece in shape. The rolling parts of the rolling wheel and the limiting roller are matched with the outer diameter of the forge piece, and the limiting roller assists the rolling wheel in rolling and forming the forge piece; a middle blank with the similar shape can be obtained through the blank manufacturing die, then the ring rolling process is carried out, the forge piece is rolled into the needed single-row conical shape, and it is guaranteed that the shape of a forge piece raceway is basically consistent with the shape of a product raceway.

Description

Technical Field

[0001] This invention relates to a forging and shaping tooling for bearing inner rings, which applies the forging and shaping of large and medium-sized single-row tapered bearing inner ring forgings using a pneumatic hammer and radial rolling mill, belonging to the field of bearing manufacturing technology. Background Technology

[0002] In recent years, with the increasing demand for medium and large bearings, finished product customers have been purchasing forgings based on the lowest price offered by price comparison. This has put great pressure on the forging industry. Under the current circumstances, it is necessary to improve the quality of bearing forgings through technological innovation and process improvement, reduce the weight of forgings, lower costs, and improve the quality of bearing forgings to meet customer quality requirements in order to remain competitive in the fierce market.

[0003] The inner ring structure of a single-row tapered roller bearing differs from that of conventional symmetrical bearings. The inner ring is an extremely asymmetrical part; its overall profile resembles a thin-walled stepped tapered sleeve with a regular cylindrical inner bore. The first key feature of its outer surface is the tapered raceway surface, whose cone angle forms a certain angle with the bearing's centerline. The second crucial feature is a guide flange at the large end, with its inner side being the raceway's terminating surface and its outer side a vertical end face. From the cross-sectional view, the wall thickness changes drastically from the large end to the small end, making near-net-shape forging extremely difficult. Summary of the Invention

[0004] In view of the above problems, the purpose of this application is to provide a forging process and tooling for the inner sleeve of a single-row tapered bearing, so that an intermediate blank with a similar shape can be obtained first through a blanking mold, and then the forging can be rolled into the required single-row tapered shape through a rolling process, ensuring that the shape of the raceway of the forging and the raceway of the product are basically consistent.

[0005] To achieve some or all of the above objectives or other objectives, this application provides the following technical solution: Forging process for the inner sleeve of a single-row tapered bearing, including the following steps: Step 1: Incoming material inspection: Check the properties of the raw materials and feed them into the system after confirming that they are qualified; Step 2, sawing and cutting: Cut the raw material into sections suitable for forging; select round steel with a diameter of 240~260 mm for the billet; Step 3: Heating: Heat the material section to the forging temperature; Step 4: Upsetting in the mold: Place the heated material segment into the upsetting mold, so that the outer diameter and shape of the material segment gradually conform to the inner cavity of the upsetting mold; Step 5: Punching blind holes in the mold: With the small end of the blank facing up and the large end facing down in the upsetting mold, use a punch to punch blind holes; Step 6, punching and removing the core: turn the blank over so that the inner large end is facing up and the small end is facing down, and punch through the blind holes on the blank to form the blank; Step 7, Flatten the end face: Make the height of the blank equal to the height of the upsetting die; Step 8, Demolding: Turn the blank over so that the smaller end is facing up and the larger end is facing down, and demold it; Step 9, Rolling and Expanding: Place the blank into the bearing inner sleeve forging and shaping fixture and roll and expand it. Step 10, Spray cooling: Cool the forging to a specific temperature by spraying or air cooling, thereby cooling the outer diameter temperature of the forging; Step 11, Spheroidizing Annealing: Heat the forging in an annealing furnace, hold it at that temperature for a period of time, and then slowly cool it in the furnace.

[0006] Furthermore, the specific steps include: Step 1: Incoming material inspection: Inspect the surface quality and markings of the raw materials, check the various indicators of the raw materials, verify the performance of the raw materials, and feed them into the system after confirming that they are qualified. Step 2: Sawing and blanking: Cut the raw material into sections suitable for forging to prepare for the forging process; the billet is made of 250 mm diameter round steel, the material is high carbon bearing steel, and it is cut by a saw; the weight is within the upper and lower limits, the end face inclination H value cannot exceed the specified value corresponding to the material diameter; and the quality is inspected by testing equipment. Step 3: Heating: Heat the material section to the forging temperature of 1050~1150℃ and hold it at that temperature for a period of time. The initial forging temperature is usually 1030~1150℃. Step 4, Upsetting in the mold: The heated material segment is placed into the upsetting mold and deformed by being continuously hammered by an air hammer. At the same time, due to the constraint of the upsetting mold, the diameter and shape of the material segment gradually conform to the inner cavity of the upsetting mold. Step 5: With the small end of the blank facing up and the large end facing down in the upsetting die, use a punch with an outer diameter of φ145mm, a taper of 0°27′30″, and a length of 125mm to punch blind holes; Step 6, punching and removing the core: turn the blank over so that the inner large end is facing up and the small end is facing down, use an air hammer to hammer the punch into the blind hole in the middle of the blank, punch through the blind hole on the blank to form the blank; Step 7, Flatten the end face: After punching, use a pneumatic hammer to hammer the end face of the blank so that the height of the blank is equal to the height of the upsetting die, which is 123mm. Step 8, Demolding: Turn the blank over so that the inner small end is facing up and the large end is facing down, place it on the pad ring, and gently tap it with an air hammer to remove it; Step 9, Rolling and Expanding: Place the blank into the rolling and expanding equipment, and roll and expand the inner hole and conical surface of the blank with a mandrel so that the inner hole and conical surface of the blank meet the process requirements. Step 10, Spray Cooling: Depending on the temperature, high carbon chromium bearing steel forgings are cooled outdoors using either air cooling or spray cooling with a dedicated cooling device. When the outer diameter temperature of the forging is cooled to 680~600℃, it turns dark cherry red. Use a forklift to move it out of the rapid cooling area and allow it to air cool naturally. Spraying water is strictly prohibited below 600℃. Lay water grates or channel steel on the site to prevent the formation of puddles. Step 11, Spheroidizing Annealing: Heat the forging to 800±10℃ in an annealing furnace, hold it at that temperature for a period of time, and then slowly cool it in the furnace.

[0007] A forging and shaping tooling for bearing inner sleeves used in forging processes includes a blanking die, a rolling roller, and a limiting roller. The blanking die includes an upsetting die and a punch, through which an intermediate blank with a similar shape is first obtained, so that the metal distribution is roughly reasonable. The rolling roller includes a wheel cover, a wheel core, and a bottom wheel, which are arranged concentrically in sequence. The outer diameter of the rolling roller and the outer diameter of the limiting roller are both provided with a rolling section with a shape similar to the outer diameter of the forging. The rolling sections of the rolling roller and the limiting roller are both configured to fit the outer diameter of the forging, and the limiting roller assists the rolling roller in rolling the forging into shape.

[0008] Furthermore, it also includes a signal roller, which is used to form the forging; the three-point positioning of the rolling roller, the limiting roller and the signal roller forms a circle to achieve the required external dimensions of the forging.

[0009] Furthermore, the shape of the inner cavity of the upsetting die is similar to but not the same as the shape of the rolling part of the rolling wheel, and the shape of the blank is a conical large arc.

[0010] Furthermore, the limiting roller is used in conjunction with the rolling wheel core, and the outer shape of the rolling part of the limiting roller is the same as that of the rolling part of the rolling wheel core; the outer diameter of the rolling wheel core is larger than that of the limiting roller.

[0011] Furthermore, the rolling wheel core is a hollow annular body with an outer diameter that forms the rolling section of the rolling wheel core. When rolling the forging, the rolling section fully engages with the forging, and the height of the rolling section is 123mm.

[0012] Furthermore, the limiting roller is an annular body with a central inner diameter hole of equal diameter at the top and bottom and a smaller inner diameter in the middle. The lower part of the annular body is the rolling part of the limiting roller, and the upper middle part is a vertical section. When rolling the forging, it cooperates with the forging through the lower rolling part. The height of the rolling part is 120mm.

[0013] Furthermore, the limiting roller is a standard part with an overall height of 340mm.

[0014] Furthermore, the rolling wheel core is connected to the ring rolling machine via a bottom wheel, and the wheel cover is fastened onto the wheel core.

[0015] Compared with the prior art, the beneficial effects of the present invention are: by optimizing the forging profile tooling structure of the bearing inner sleeve, by using the combination of the limiting roller and the rolling wheel and adopting the corresponding forging process to achieve near-net-shape forging of the single-row conical inner ring forging, the market competitiveness is improved, the material utilization rate of forging is increased, and the machining efficiency is also improved. Attached Figure Description

[0016] Figure 1 This is a flowchart of the inner ring forging process of the present invention; Figure 2 The diagram illustrates the product during the processing: material segment (sawing, heating) — blank (after forming in the upsetting mold) — blank (after punching blind holes in the mold) — blank (after removing the core) — blank (after rolling and expanding). Figure 3 This is a schematic diagram of the assembly of the inner ring forging in the machining state according to the present invention; Figure 4 This is a structural diagram of the rolling wheel core of the contouring tooling of the present invention; Figure 5 This is an assembly drawing of the roller core, bottom roller, and roller cover of the present invention; Figure 6 This is a schematic diagram of the upsetting die during the blank preparation process of the present invention; Figure 7 This is a schematic diagram of the punch structure in the punching part of the present invention; Figure 8 This is a schematic diagram of the structure of the limiting roller of the contouring tooling of the present invention; Figure 9 This is a schematic diagram of the blank structure of the present invention; Figure 10 This is a schematic diagram of the bearing inner ring forging structure of the present invention; Figure 11 This is a finished product image of the single-row tapered roller inner ring processed according to the present invention; In the diagram, 1. bottom wheel, 2. wheel cover, 3. wheel core, 4. upsetting die, 5. punch, 6. limiting roller, 7. blank, 8. inner ring forging, 9. signal roller, 10. finished single-row tapered roller inner ring. Detailed Implementation

[0017] To make the structure and function of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0018] See appendix Figure 1-11 The forging process for the inner sleeve of a single-row tapered bearing includes the following steps: Step 1: Incoming material inspection: Inspect the surface quality and markings of the raw materials, check the various indicators of the raw materials, verify the performance of the raw materials, and feed them into the system after confirming that they are qualified. Step 2: Sawing and blanking: Cut the raw material into sections suitable for forging to prepare for the forging process; the billet is made of 250 mm diameter round steel, the material is high carbon bearing steel, and it is cut by a saw; the weight is within the upper and lower limits, the end face inclination H value cannot exceed the specified value corresponding to the material diameter; and the quality is inspected by testing equipment. Step 3: Heating: Heat the material section to the forging temperature of 1050~1150℃ and hold it at that temperature for a period of time. The initial forging temperature is usually 1030~1150℃. Step 4, Upsetting in the mold: The heated material segment is placed into the upsetting mold and deformed by being continuously hammered by an air hammer. At the same time, due to the constraint of the upsetting mold, the diameter and shape of the material segment gradually conform to the inner cavity of the upsetting mold. Step 5: With the small end of the blank facing up and the large end facing down in the upsetting die, use a punch with an outer diameter of φ145mm, a taper of 0°27′30″, and a length of 125mm to punch blind holes; Step 6, punching and removing the core: turn the blank over so that the inner large end is facing up and the small end is facing down, use an air hammer to hammer the punch into the blind hole in the middle of the blank, punch through the blind hole on the blank to form the blank; Step 7, Flatten the end face: After punching, use a pneumatic hammer to hammer the end face of the blank so that the height of the blank is equal to the height of the upsetting die, which is 123mm. Step 8, Demolding: Turn the blank over so that the inner small end is facing up and the large end is facing down, place it on the pad ring, and gently tap it with an air hammer to remove it; Step 9, Rolling and Expanding: Place the blank into the rolling and expanding equipment, and roll and expand the inner hole and conical surface of the blank with a mandrel so that the inner hole and conical surface of the blank meet the process requirements. Step 10, Spray Cooling: Depending on the temperature, high carbon chromium bearing steel forgings are cooled outdoors using either air cooling or spray cooling with a dedicated cooling device. When the outer diameter temperature of the forging is cooled to 680~600℃, it turns dark cherry red. Use a forklift to move it out of the rapid cooling area and allow it to air cool naturally. Spraying water is strictly prohibited below 600℃. Lay water grates or channel steel on the site to prevent the formation of puddles. Step 11, Spheroidizing Annealing: Heat the forging to 800±10℃ in an annealing furnace, hold it at that temperature for a period of time, and then slowly cool it in the furnace.

[0019] The forging process route is as follows: Incoming material inspection—sawing and blanking—heating—upsetting in-mold forming—blind hole punching in-mold—core removal—flat end face—demolding—rolling and expanding—spray cooling—spheroidizing annealing.

[0020] By following the above process route, the relevant requirements of the product can be achieved. It is important to note that the machining allowance should be uniform across all raceway surfaces to ensure that the cutting tool is subjected to uniform force during machining.

[0021] The bearing inner ring forging conformal tooling includes: a bottom wheel 1, a wheel cover 2, a wheel core 3, and a limiting roller 6; the outer diameter of the rolling wheel core 3 and the outer diameter of the limiting roller 6 are both provided with rolling parts that are similar in shape to the outer diameter of the bearing inner ring forging 8; the rolling parts of the rolling wheel and the limiting roller correspond to the outer diameter of the bearing inner ring forging 8 and are respectively configured to fit together, and the limiting roller 6 assists the rolling wheel core 3 in rolling the bearing inner ring forging 8 into shape.

[0022] The limiting roller 6 is used in conjunction with the rolling wheel core 3. The outer shape of the rolling part of the limiting roller 6 is the same as that of the rolling part of the rolling wheel core 3. The outer diameter of the rolling wheel core 3 is larger than that of the limiting roller 6.

[0023] The bearing of the present invention is a medium-to-large single-row tapered bearing inner ring 10, which forms a certain angle between its raceway surface and the axial center line. It is an extremely asymmetrical part, with the wall thickness changing drastically from the large end to the small end.

[0024] The rolling wheel core 3 is a hollow annular body with an outer diameter that is the rolling part of the rolling wheel core. When rolling the forging, the rolling part fully cooperates with the forging. The height of the rolling part is 123mm.

[0025] The limiting roller 6 is an annular body with the same inner diameter hole at the top and bottom and a smaller inner diameter in the middle. The lower part of the annular body is the rolling part of the limiting roller, and the upper middle part is a vertical section. When rolling the forging 8, it cooperates with the forging through the lower rolling part. The height of the rolling part is 120mm.

[0026] The reason why the height of the rolling part of the rolling wheel core 3 is slightly larger than the height of the limiting roller 6 is that the rolling wheel is processed in a hot state. After reaching room temperature and cooling, it will shrink to a certain extent to ensure a certain tolerance range.

[0027] The limiting roller 6 is a standard part with an overall height of 340mm. When the forging 8 is rolled in a contour rolling motion, the limiting roller 6 acts as an auxiliary to the rolling wheel core 3, and works with the rolling wheel core 3 to roll the forging 8 into the required single-row conical shape.

[0028] The rolling wheel core 3 is connected to the ring rolling machine via the bottom wheel 1. The forging 8 is fitted onto the mandrel, which supports the forging. The rolling wheel core 3 acts as the active drive wheel, driving the forging 8 to rotate. The limiting roller 6 acts as the driven wheel, and through the cooperation of the limiting roller 6, the forging 8 is rolled in a contour-following manner. After rolling, the forging 8 undergoes heat treatment, machining, grinding, and forming processes to finally become a single-row conical inner ring finished product. Figure 10 As shown.

[0029] In order to effectively limit the outer diameter of the forging, the profiling tooling of the present invention is also provided with a signal roller 9 for forming the forging; the signal roller 9 cooperates with the forging 8, and the three-point positioning of the rolling wheel core 3, the limiting roller 6 and the signal roller 9 forms a circle to achieve the required outer dimensions of the forging.

[0030] When the contouring tooling of the present invention is used in the blanking process after the blank has been heated, the cylindrical material segment is forged in the upsetting mold 4 by air hammer to achieve the large arc cone shape of the blank 7.

[0031] When the material segment is formed in the same shape as the inner cavity of the upsetting die 4, it is punched by the punch 5.

[0032] The use of the contouring tooling of the present invention is to first obtain an intermediate blank with a similar shape through the blanking mold after the blank is heated, and then perform the rolling process to roll the forging into the required single-row conical shape, so as to ensure that the shape of the forging raceway and the product raceway are basically consistent.

[0033] This invention successfully completed the forging process using its contouring tooling, and after verification through machining, it passed the full-size acceptance test at the customer's site, and the product was officially supplied in batches.

[0034] In the description of this invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front end", "rear end", "both ends", "one end", "the other end", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0035] The above-disclosed embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of this application. Therefore, any equivalent variations made in accordance with the claims of this application shall still fall within the scope of this application.

Claims

1. A single-row tapered bearing inner race forging process, characterized in that: Comprise the following steps: Step one, incoming inspection: check the performance of raw materials, confirm qualified after feeding; Step two, saw cutting: cut the raw material into suitable for forging processing section; blank selection diameter of 240~260mm round steel; Step three, heating: the section is heated to forging temperature; Step four, upset mode forming: the heated section is put into the upset mode, the section gradually conforms to the shape of the inner cavity of the upset mode; Step five, blind hole punching: the blank is in the upset mode, the small head is up, the big head is down, and the punch is used to punch the blind hole; Step six, hole punching: the blank is turned over, the big head is up, the small head is down, the blind hole on the blank is punched through, and the blank is formed; Step seven, flat end face: the height of the blank is equal to the height of the upset mode; Step eight, demolding: the blank is turned over, the small head is up, the big head is down, and the blank is demolded; Step nine, rolling and expanding: the blank is put into the forging processing tooling and rolled and expanded; Step ten, spray cooling: the forged piece is cooled to a certain temperature by spraying or air cooling, and the outer diameter temperature of the forged piece is cooled; Step eleven, spheroidizing annealing: the forged piece is heated in the annealing furnace, and slowly cooled with the furnace after a period of time.

2. The single-row tapered bearing inner race forging process of claim 1, wherein: Specifically, the following steps are included: Step one: incoming inspection: the surface quality and identification of the raw material are accepted, and the indexes of the raw material are tested, the performance of the raw material is checked, and the feeding is carried out after the confirmation of qualified; Step two: saw cutting: cut the raw material into suitable for forging processing section, prepare for forging process; blank selection diameter of 250mm round steel, material is high carbon bearing steel, which is obtained by sawing machine; the weight meets the upper and lower limit range, the end face inclination H value cannot exceed the corresponding specified value of the material diameter; and the quality is tested by detection equipment; Step three, heating: the section is heated to forging temperature 1050~1150℃, and the temperature is kept for a period of time, the initial forging temperature is usually 1030~1150℃; Step four, upset mode forming: the heated section is put into the upset mode, the section is deformed by constantly hammering with air hammer, and the section gradually conforms to the shape of the inner cavity of the upset mode due to the limitation of the upset mode; Step five, blank in the upset mode, small head up, big head down, use the punch with outer diameter φ145mm, taper 0°27′30″, length 125mm to punch the blind hole; Step six, hole punching: the blank is turned over, the big head is up, the small head is down, the air hammer is used to hammer the punch into the blind hole in the middle of the blank, the blind hole on the blank is punched through, and the blank is formed; Step seven, flat end face: after punching, the air hammer is used to hammer the end face of the blank, so that the height of the blank is equal to the height of the upset mode, and the height is 123mm; Step eight, demolding: the blank is turned over, the small head is up, the big head is down, and is placed on the spacer ring, which can be knocked off by air hammer; Step nine, rolling and expanding: the blank is put into the rolling and expanding equipment, the inner hole and taper of the blank are rolled and expanded by the core rod, so that the inner hole and taper of the blank meet the process needs; Step ten, spray cooling: according to the temperature, high carbon chromium bearing steel forgings are cooled by air cooling or special cooling device spray cooling in the outdoor cooling device, the outer diameter temperature of the forging is cooled to 680~600℃, and the dark cherry red color is obtained, and the forging is removed from the rapid cooling area by a forklift and naturally air cooled; water is strictly prohibited below 600℃, and water grating or channel steel is laid on the site to prevent the formation of water pools; Step eleven, spheroidizing annealing: the forging is heated to 800±10℃ in the annealing furnace, and slowly cooled in the furnace for a period of time.

3. A bearing inner sleeve forging profiling tooling for use in the forging process of any of claims 1-2, characterized in that: It comprises a blanking die, a rolling wheel and a limiting roller (6); the blanking die comprises an upsetting die (4) and a punch (5), and a similar intermediate rough casting is obtained through the blanking die, so that the metal distribution is roughly reasonable; the rolling wheel comprises a wheel cover (2), a wheel core (3) and a bottom wheel (1), and the wheel cover (2), the wheel core (3) and the bottom wheel (1) are arranged in sequence and concentrically; the outer diameter of the rolling wheel and the outer diameter of the limiting roller (6) are provided with rolling portions similar to the shape of the outer diameter of the forging (8); the rolling portions of the rolling wheel and the limiting roller (6) are arranged in cooperation with the outer diameter of the forging (8), and the rolling wheel is assisted by the limiting roller (6) to roll and form the forging (8).

4. The bearing cup swaging tooling fixture of claim 3, wherein: It also comprises a signal roller (9) for forming the forging (8); the three-point positioning of the rolling wheel, the limiting roller (6) and the signal roller (9) forms a circle to realize the required outer shape size of the forging (8).

5. The bearing cup swaging tooling fixture of claim 3, wherein: The inner cavity shape of the upsetting die (4) is similar to but not the same as the rolling portion of the rolling wheel, and the shape of the blanking piece (7) is a large circular arc conical shape.

6. The bearing cup swaging tooling fixture of claim 3, wherein: The limiting roller (6) is used in combination with the rolling wheel core (3), the rolling portion of the limiting roller (6) has the same outer shape structure as the rolling portion of the rolling wheel core (3); and the outer diameter size of the rolling wheel core (3) is larger than the outer diameter size of the limiting roller (6).

7. The bearing cup swaging tooling fixture of claim 3, wherein: The rolling wheel core (3) is a hollow annular body, the outer diameter of the annular body is the rolling portion of the rolling wheel core (3), and the rolling portion is completely matched with the forging (8) during rolling.

8. The bearing cup swaging tooling fixture of claim 3, wherein: The limiting roller (6) is a hollow annular body with the same upper and lower inner diameters and a small middle inner diameter, the lower part of the annular body is the rolling portion of the limiting roller (6), the middle and upper parts are vertical sections, and the rolling portion of the lower part is matched with the forging (8) during rolling.

9. The bearing cup swaging tooling fixture of claim 3, wherein: The limiting roller (6) is a standard part with a total height of 340mm.

10. The bearing cup swaging tooling fixture of claim 3, wherein: The rolling wheel core (3) is connected to the rolling ring machine through the bottom wheel (1), and the wheel cover (2) is buckled on the wheel core (3).

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