Method of producing a stamped unitary steel retainer

Abstract

The present application relates to the technical field of precision machinery transmission component production, and discloses a production method of stamping type integral steel retainer, which comprises the following steps: A, material selection; B, blank making: forming a thin-walled pipe body corresponding to a product; C, excess material cutting: cutting off the excess burrs on both sides of the thin-walled pipe body; D, retainer stamping forming: stamping a plurality of cyclic grooves connected in head-to-tail manner by using a die, the inner ring center of the stamped cyclic groove is lower than the outer wall height of the thin-walled pipe body, and the round corner between the outer ring of the cyclic groove and the outer wall of the pipe body is increased; E, excess material cutting: cutting off the excess shape on both sides after forming; F, cross hole stamping: the cyclic groove comprises a working ball channel and a non-working ball channel, and a cross hole is stamped at the bottom of the working ball channel by using a die; G, shaping; and H, polishing, wherein the retainer produced by the above method has the advantages of high temperature resistance, less material consumption and high precision.

Description

Technical Field

[0001] This invention relates to the field of precision mechanical transmission component manufacturing technology, and in particular to a method for producing a stamped integral steel cage. Background Technology

[0002] Linear bearings are the main transmission components of linear motion systems and are widely used in linear transmission machinery and equipment, CNC machine tools, medical machinery, food processing machinery, printing machinery, precision instruments, textile machinery, metal cutting machinery, large-scale cargo handling machinery, office equipment automation devices and other industries.

[0003] The cage inside a linear bearing is primarily made of either plastic or steel. The plastic used is industrial-grade PA66. (Refer to...) Figure 1 As shown, this material is produced by injection molding. It has low high-temperature resistance and will deform when the temperature exceeds 120°C. The thinner edge of the circulation groove is prone to wear, which hinders the movement of the steel balls and results in a short service life. However, because the manufacturing process of this material is relatively simple and it can be mass-produced, it can meet the needs of most working environments with moderate temperatures and is widely used.

[0004] Steel cages can withstand temperatures above 150℃, therefore, they are essential in some high-temperature and other special environments. There are two main production methods for existing steel cages: the first is assembly after separate production, and the second is integral production. The first method involves cutting ST14 steel plates to the required size and then stamping them into individual raceway circulation grooves using a special mold. Each set of circulation grooves has working and non-working raceways, with the through-hole being the working raceway. During assembly, each individual circulation groove is filled with steel balls and placed at the corresponding position on the inner wall of the outer ring. Clamps are used to secure it to the outer ring end face (to prevent displacement). After several sets of circulation grooves on the inner wall of the outer ring are filled, two inner rings are installed at the inner diameter of both ends of the cage to support and fix each set of circulation grooves. Finally, retaining rings are pressed into the inner groove of the outer ring to tightly lock both ends of the cage and prevent movement.

[0005] The disadvantages of the first production method are: a) Each bearing requires 4 to 8 individual circulating groove iron plates, resulting in very low assembly efficiency. The structure of a single circulating groove plate is referenced... Figure 2 As shown; b. Since the several circulating grooves are not a complete unit, each piece is fixed by the inner ring support. There will be a certain gap during use. When subjected to a large external force, it is easy to loosen and deviate from the center of the raceway. This not only reduces the accuracy of the bearing movement, but may also directly damage it if the loosening is serious.

[0006] The disadvantages of the second production method are: c. The deformation required for the integral steel cage during stamping is 6 times that of a single side. In order to achieve a uniform and dimensionally compliant shape of 6 raceway circulation grooves, the initial material volume required increases, resulting in a large diameter of the tubular blank. However, with a large blank tube diameter, it is difficult to ensure that the 6 raceways are punched out evenly during stamping, often resulting in deviation. If the blank tube diameter is reduced, there will be insufficient material, the circulation grooves cannot be pressed out, or there may be cracking. The above problems are also the reason why there is no integral steel cage on the market. Summary of the Invention

[0007] To address the shortcomings of existing steel cages, which can only be produced in single-piece form and suffer from low assembly efficiency, low precision, and short service life, a stamped integral steel cage production method is provided that significantly improves assembly efficiency, precision, and service life.

[0008] To solve the above-mentioned technical problems, the present invention provides a method for producing a stamped integral steel cage, comprising the following steps:

[0009] A. Material selection;

[0010] B. Making the blank: forming a thin-walled tube corresponding to the product;

[0011] C. Excess material removal: Remove excess burrs from both sides of the thin-walled tube;

[0012] D. Cage stamping: Multiple circulation grooves connected end to end are stamped out using a die. The center of the inner ring of the stamped circulation groove is lower than the height of the outer wall of the thin-walled tube. At the same time, the radius between the outer ring of the circulation groove and the outer wall of the tube is increased.

[0013] E. Excess material removal: Remove excess material from both sides of the molded product to make the end faces of the product flat.

[0014] F. Punching transverse holes: The circulation groove includes working ball track and non-working ball track. A mold is used to punch transverse holes at the bottom of the working ball track.

[0015] G. Plastic surgery;

[0016] H. Polishing.

[0017] The innovation of this solution lies in step D, in which the stamping die is improved. The resulting changes are that the product has two distinct features that are completely different from the existing ones. Feature 1 is that the center of the inner ring of the stamped circulation groove is lower than the height of the outer wall of the thin-walled tube. Feature 2 is that the radius between the outer ring of the circulation groove and the outer wall of the tube is increased. This feature can produce a "material borrowing" effect during stamping, which can not only make up for the insufficient precision caused by large material usage, but also avoid the problem of circulation groove breakage caused by small material usage.

[0018] The reason for insufficient precision due to excessive material usage is that using thin-walled tubes of the same wall thickness will inevitably lead to a larger diameter, resulting in an excessive gap between the blank and the mold. During stamping, the blank may not be able to be centered. Once the blank is offset, it will inevitably cause uneven distribution of the multiple circumferentially distributed circulation grooves, resulting in insufficient precision.

[0019] The reason for damage caused by using less material is that: using thin-walled tubes with the same wall thickness, less material will inevitably lead to a smaller diameter. The circulating groove made by the existing mold will cause the edge of the circulating groove on the blank after the diameter is reduced to be thinner, which is easy to wear under stress and may even cause direct breakage during stamping.

[0020] In this method, the middle of the circulation groove is lower than the outer wall of the thin-walled tube, directly achieving the effect of diameter reduction at the middle of the circulation groove. This diameter reduction allows some material located in the middle of the circulation groove to be "relocated" to the position where the circulation groove needs to be opened. The addition of rounded corners is because the arc corresponding to the rounded corner is less than the length of the two segments of the original right angle, thus "relocating" some material from the thin-walled tube to the stamping area of ​​the circulation groove. The larger the rounded corner, the more material is "relocated". Combining the above two features, corresponding material is "relocated" to the circulation groove setting area both inside and outside the circulation groove. This results in sufficient material at the corresponding location of the circulation groove to achieve a uniform stamping effect when stamping the circulation groove. Therefore, the accuracy of the stamped cage can be guaranteed. Furthermore, due to the diameter reduction effect at the middle of the circulation groove, the gap between the thin-walled tube and the mold remains constant, which can improve the uniformity of each circulation groove after stamping. This results in a cage with high precision, less material, and good high-temperature resistance in the final formed cage. The one-piece formed cage can also improve the final bearing assembly efficiency.

[0021] Preferably, in step D, the height difference H0 between the center of the inner ring and the outer wall of the thin-walled tube is in the range of 0.9 mm to 8.2 mm; the radius R2 of the fillet between the outer ring of the circulation groove and the outer wall of the tube is in the range of 0.7 mm to 4.1 mm.

[0022] Using the above scheme, H0 is the value of the radius R1 of the thin-walled tube body minus the radius R at the center of the inner ring, that is, the reduction value at the center of the inner ring. The reduction values ​​corresponding to different sizes of cages are different, and the corresponding fillet radii are also different. As the cage size increases, the vertical H0 and R2 increase synchronously, and the increasing trend of both is proportional to the size of the rolling element.

[0023] Preferably, step B includes:

[0024] b1. Cutting the material into strips or pieces;

[0025] b2. Blanking: Evenly stamp multiple round blanks onto the strip-shaped material sheet;

[0026] b3. Stretching: Each circular blank is stretched to form a thin-walled tube corresponding to the product.

[0027] Using the above scheme, there are two ways to form thin-walled tubes. One way is to use a stretching method to form hollow tubes one by one from circular blanks.

[0028] Preferably, in step b3, the stretching includes two intermittent stretching processes. In the first stretching process, at least two consecutive stretching processes are required to stretch the round blank into a cylindrical shape. In the second stretching process, at least one stretching process is required to stretch the cylindrical blank formed in the previous step to the finished size.

[0029] Using the above method, the first stretching process involves more than two consecutive stretchings to initially stretch the product into a cylindrical shape. The second stretching process involves more than one stretching to further stretch the cylindrical shape to the corresponding size of the finished product.

[0030] Preferably, step B includes:

[0031] b1' Weld the two sides of the steel strips required for different sizes of capillary tubes to form a tubular shape;

[0032] b2', Cut the steel pipe formed by b1' into thin-walled pipes 3 to 5 meters long;

[0033] b3', Cut the thin-walled tube formed by b2' into a thin-walled tube body corresponding to a product.

[0034] The above method involves first forming a long, thin-walled tube, and then cutting it into multiple hollow tubes.

[0035] Preferably, step b1' requires pretreatment, which includes: steel strip rolling, annealing and cold rolling.

[0036] Preferably, step G involves shaping the material using a shaping mold on a 60T hydraulic press.

[0037] Preferably, in step H, a vibratory polishing machine is used to place a polishing stone, add a gloss enhancer, and polish the surface.

[0038] Preferably, the polishing time is 2 to 3 hours.

[0039] Preferably, step H is followed by step I, which includes cleaning, rust prevention, and placement in the semi-finished product warehouse.

[0040] This invention, by adopting the above technical solutions, has significant technical effects: In step D, the stamping die is improved, resulting in two distinct features on the product that are completely different from existing ones. Feature 1 is that the center of the inner ring of the stamped circulation groove is lower than the outer wall height of the thin-walled tube. Feature 2 is the increase of the fillet between the outer ring of the circulation groove and the outer wall of the tube. Feature 1 directly achieves the effect of diameter reduction in the middle of the circulation groove. This diameter reduction allows some material located in the middle of the circulation groove to be "repurposed" for the position where the circulation groove needs to be opened. The setting of Feature 2, because the arc corresponding to the fillet is smaller than the original two segments of the right angle... The length of the tube allows some material to be "borrowed" from the thin-walled tube to the stamping area of ​​the circulation groove. The larger the radius of the corner, the more material is "borrowed". Combining the above two characteristics, there is corresponding material "borrowed" from both the inside and outside of the circulation groove to the circulation groove setting area. This results in that when stamping the circulation groove, the amount of material at the corresponding part of the circulation groove is sufficient to achieve a uniform stamping effect. Therefore, the accuracy of the stamped product can be guaranteed. Furthermore, due to the diameter reduction effect in the middle of the circulation groove, the gap between the thin-walled tube and the mold is always maintained, which can improve the uniformity of each circulation groove after stamping, resulting in high precision and less material used in the final formed cage. Attached Figure Description

[0041] Figure 1 This is an isometric view of a cage made of PA66 plastic injection molding using existing technology;

[0042] Figure 2 This is a front view of a pre-existing single-piece circulating groove cage;

[0043] Figure 3 This is a schematic diagram of the strip-shaped material after being cut in this embodiment;

[0044] Figure 4 This is a schematic diagram of the stamping of a circular blank in this embodiment;

[0045] Figure 5 This is a schematic diagram of the circular billet after the first stretching process in this embodiment;

[0046] Figure 6 This is a schematic diagram of the circular billet after the second stretching process in this embodiment;

[0047] Figure 7 This is a cross-sectional view of the thin-walled barrel-shaped blank after it has been cut at both ends in this embodiment;

[0048] Figure 8 This is a front view of the thin-walled tubular blank after it has passed through the stamping circulation groove in this embodiment;

[0049] Figure 9 yes Figure 8 A sectional view of AA;

[0050] Figure 10This is a cross-sectional view of a thin-walled tube blank after it has passed through a stamping circulation groove, according to existing technology.

[0051] Figure 11 This is a front view of the thin-walled tubular blank after it has been punched with transverse holes, according to this embodiment.

[0052] Figure 12 yes Figure 11 A cross-sectional view of BB;

[0053] Figure 13 This is an isometric view of the thin-walled tubular blank after punching a transverse hole in this embodiment;

[0054] Figure 14 This is an isometric view of the cage and the collar assembly in this embodiment.

[0055] The parts referred to by the numbers in the above attached figures are as follows: 1. Strip-shaped sheet; 2. Circular billet; 3. Thin-walled tube; 4. Circulation groove; 5. Horizontal hole. Detailed Implementation

[0056] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0057] Example 1

[0058] A method for producing a stamped integral steel cage includes the following steps:

[0059] A. Material selection: Select a steel plate with small deformation and reasonable wall thickness. In this embodiment, ST14 steel plate is used.

[0060] B. Blank Making: This step includes: b1. Shearing: On a shearing machine, the steel plate selected in step A is sheared into strips of uniform width 1 according to the diameter of the product; b2. Blanking: Using a 40T machine tool, multiple circular blanks 2 are punched out from the strips obtained in step b1; b3. Stretching: Stretching includes two intermittent stretching processes. In the first stretching process, a 60T hydraulic press is used to stretch the circular blanks 2 into a cylindrical shape at least twice. In this embodiment, three stretching processes are used to initially stretch the circular blanks 2 into a cylindrical shape. Then, in the second stretching process, the cylindrical blanks are stretched at least once. In this embodiment, the cylindrical blanks are stretched into a cylindrical shape corresponding to the finished product size through two stretching processes.

[0061] C. Excess material removal: Use a laser cutting machine to remove the excess burrs on both sides of the cylindrical billet to form a thin-walled tube 3;

[0062] D. Cage stamping: This includes stamping the circulation groove 4. During the stamping of the circulation groove 4, multiple circulation grooves 4 connected end to end are stamped using a die. The center of the inner ring of the stamped circulation groove 4 is lower than the height of the outer wall of the thin-walled tube 3. At the same time, the radius of the rounded corner between the outer ring of the circulation groove 4 and the outer wall of the tube is increased. The height difference H0 between the center of the inner ring and the outer wall of the thin-walled tube 3 ranges from 0.9mm to 8.2mm. H0 = R1 (radius of thin-walled tube 3) - R (radius of the middle area of ​​the circulation groove 4); the radius R2 of the rounded corner between the outer ring of the circulation groove 4 and the outer wall of the tube ranges from 0.7mm to 4.1mm.

[0063] E. Excess material removal: Remove excess shape from both sides after molding, making the end faces of the product flat.

[0064] F. Punching transverse holes 5: The circulation groove 4 includes working ball channels and non-working ball channels. The mold is inserted into the inner hole of the blank, and a 16T punch press is used to punch transverse holes 5 at the bottom of the working ball channels. The width and length of the transverse holes 5 must be ensured under the constraint of the mold to ensure that the steel balls can pass through smoothly without falling or getting stuck.

[0065] G. Shaping: Using shaping molds on a 60T hydraulic press, the deformation of the billet at the circulation groove 4 and the transverse hole 5 caused by the stamping process is improved and corrected, thereby improving the roundness of the billet.

[0066] H. Polishing: Place the shaped blank into a vibratory polishing machine, add appropriately sized polishing stones and brightening agents, and polish for 2-3 hours to make the product surface smooth and improve the surface roughness.

[0067] 1. Clean, apply rust-preventive oil, and put into the semi-finished product warehouse.

[0068] In the aforementioned stamping process, step D is the core design point. In step D, the stamping die is improved, resulting in two distinct features on the product that are completely different from existing ones. Feature 1 is that the center of the inner ring of the stamped circulation groove 4 is lower than the outer wall height of the thin-walled tube 3. Feature 2 is increasing the fillet between the outer ring of the circulation groove 4 and the outer wall of the tube. Feature 1 directly achieves the effect of diameter reduction in the middle of the circulation groove 4. This diameter reduction allows some material located in the middle of the circulation groove 4 to be "repurposed" for the area where the circulation groove 4 needs to be created. Feature 2, because the arc corresponding to the fillet is shorter than the length of the two segments of the original right angle, thus… Part of the material from the thin-walled tube 3 is "borrowed" to the stamping area of ​​the circulation groove 4. The larger the radius, the more material is "borrowed". Combining the above two characteristics, there is corresponding material "borrowed" from both the inside and outside of the circulation groove 4 to the location of the circulation groove 4. This results in that when stamping the circulation groove 4, the amount of material at the corresponding location of the circulation groove 4 is sufficient to achieve a uniform stamping effect. Therefore, the accuracy of the stamped product can be guaranteed. Furthermore, due to the diameter reduction effect in the middle of the circulation groove 4, the gap between the thin-walled tube 3 and the mold remains constant, which can improve the uniformity of each circulation groove 4 after stamping, resulting in high precision and less material used in the final formed cage.

[0069] Example 2

[0070] The difference between this embodiment and Embodiment 1 lies in the production method of the thin-walled tube 3. Step B in this embodiment includes: b0', cutting steel strips of different widths according to the size of different models of cages, and performing pretreatments such as rolling, annealing and cold rolling on the steel strips to obtain curved steel strips; b1', welding the two sides of the steel strip to form a tube; b2', cutting the steel tube formed by b1' into thin-walled tubes of 3 to 5 meters in length; b3', cutting the thin-walled tubes formed by b2' into thin-walled tubes 3 corresponding to one product.

[0071] The thin-walled tube 3 obtained through the above steps is different from the barrel-shaped blank obtained in Example 1. In the subsequent step C, after the excess burrs on both sides of the thin-walled tube 3 are removed by a laser cutting machine, the obtained blank is the same as the blank obtained in step C of Example 1.

[0072] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for producing a stamped integral steel cage, characterized in that, Includes the following steps: A. Material selection; B. Making blanks: forming a thin-walled tube corresponding to the product (3); C. Excess material removal: Remove excess burrs on both sides of the thin-walled tube (3); D. Cage stamping: Multiple interconnected circulation grooves (4) are stamped using a die. The center of the inner ring of the stamped circulation groove (4) is lower than the height of the outer wall of the thin-walled tube (3). At the same time, the radius of the fillet between the outer ring of the circulation groove (4) and the outer wall of the tube is increased. The height difference H0 between the center of the inner ring and the outer wall of the thin-walled tube (3) is 0.9mm to 8.2mm. The radius R2 of the fillet between the outer ring of the circulation groove (4) and the outer wall of the tube is 0.7mm to 4.1mm. E. Excess material removal: Remove excess material from both sides of the molded product to make the end faces of the product flat. F. Punching transverse holes (5): The circulation groove (4) includes working ball track and non-working ball track. A transverse hole (5) is punched out at the bottom of the working ball track using a mold. G. Plastic surgery; H. Polishing.

2. The method for producing a stamped integral steel cage according to claim 1, characterized in that: Step B includes: b1. Cut the material into strips (1); b2. Blanking: A number of circular blanks (2) are uniformly stamped out on the strip-shaped material (1); b3. Stretching: Each circular blank (2) is stretched to form a thin-walled tube (3) corresponding to the product.

3. The method for producing a stamped integral steel cage according to claim 2, characterized in that: In step b3, stretching includes two intermittent stretching processes. In the first stretching process, at least two consecutive stretching processes are required to stretch the circular blank (2) into a cylindrical shape. In the second stretching process, at least one stretching process is required to stretch the cylindrical blank formed in the previous step to the finished size.

4. The method for producing a stamped integral steel cage according to claim 1, characterized in that: Step B includes: b1' Weld the two sides of the steel strips required for different sizes of capillary tubes to form a tubular shape; b2', Cut the steel pipe formed by b1' into thin-walled pipes 3-5 meters long; b3', Cut the thin-walled tube formed by b2' into a thin-walled tube body corresponding to a product (3).

5. The method for producing a stamped integral steel cage according to claim 4, characterized in that: Step b1' requires pretreatment, which includes: steel strip rolling, annealing and cold rolling.

6. The method for producing a stamped integral steel cage according to claim 1, characterized in that: Step G involves shaping the material using a shaping mold on a 60T hydraulic press.

7. The method for producing a stamped integral steel cage according to claim 1, characterized in that: Step H involves using a vibratory polishing machine, placing a polishing stone inside, adding a gloss enhancer, and then polishing.

8. The method for producing a stamped integral steel cage according to claim 1, characterized in that: Polishing time is 2-3 hours.

9. The method for producing a stamped integral steel cage according to claim 1, characterized in that: Step H is followed by step I, which includes cleaning, rust prevention, and placement in the semi-finished product warehouse.

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