JP2006341255A - High-precision ring manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method capable of easily and efficiently manufacturing a high-precision ring for a stock to manufacture a bearing ring to constitute a radial ball bearing through cold working. <P>SOLUTION: A first high-precision ring 14 and a second intermediate stock 27 shown in Fig.(F) are manufactured from a billet 13 shown in Fig.(A) via a preliminary intermediate stock 16 shown in Fig.(B), a second preliminary intermediate stock 17 shown in Fig.(C), a third preliminary intermediate stock 20 shown in Fig.(D) and a first intermediate stock 23 shown in Fig.(E). An inner ring is formed by the first high-precision ring 14. The second intermediate stock 27 is subjected to inversion working for changing the sectional shape by 90° in the direction in which the inside diameter side having the large thickness dimension is expanded and similarly the outside diameter side having the small thickness dimension is contracted. A cylindrical second high-precision ring is manufactured while regulating the inside diameter, the outside diameter and the axial length, and an outer ring is formed out of the second high-precision ring. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The method for producing a high-accuracy ring according to the present invention is used for producing a high-accuracy ring which is a material for producing an inner ring and an outer ring constituting a radial ball bearing by cold working, for example. In addition, radial ball bearings incorporating inner and outer rings made of such a high-precision ring are, for example, electric motors incorporated in various household electrical products such as vacuum cleaners and ventilation fans, or rotations of various auxiliary machinery for automobiles, etc. Used for parts that do not require a high degree of rotational accuracy, such as support parts.

  A radial ball bearing 1 as shown in FIG. 6 is incorporated in a rotation support portion of various rotating devices. This radial ball bearing 1 is of a single-row deep groove type, and has a plurality of balls 4, 4 installed between an outer ring 2 and an inner ring 3 arranged concentrically with each other. Of these, a deep groove type outer ring raceway 5 is formed on the axially intermediate portion of the inner peripheral surface of the outer ring 2, and a deep groove type inner ring raceway 6 is formed on the entire outer periphery of the inner ring 3. is doing. The balls 4 and 4 are arranged so as to be able to roll between the outer ring raceway 5 and the inner ring raceway 6 while being held by a cage 7. With this configuration, the outer ring 2 and the inner ring 3 can freely rotate relative to each other. In the example shown in FIG. 6, a metal corrugated cage is used as the cage 7, but a synthetic resin crown-shaped cage is often used. Further, the outer peripheral edge of each sealing plate (including a contact-type seal plate and a non-contact-type shield plate; the same applies throughout the present specification) is engaged with the engaging grooves formed on the inner peripheral surfaces of both ends of the outer ring 2. In many cases, a structure that stops is used. In this case, the inner peripheral edges of the both sealing plates are slidably contacted or closely opposed to the outer peripheral surfaces of both end portions of the inner ring 3 over the entire periphery.

  Conventionally, in order to construct the races such as the outer ring 2 and the inner ring 3 constituting the radial ball bearing 1 as described above, generally, first, the shape and dimensions close to the finished product are obtained by forging and cutting. Had an intermediate material to have. The intermediate material is subjected to a heat treatment for curing the surface, and then the surface and the surface including the raceway surface such as the outer ring raceway 5 and the inner ring raceway 6 are made to have predetermined dimensions and surface roughness. Polishing was performed to obtain the above-described race. Such a manufacturing method of the raceway is not only troublesome in material yield but also cumbersome and costly.

Patent Documents 1 and 2 describe a method of making a raceway ring of a radial ball bearing centering on forging.
First, in the case of the invention described in Patent Document 1, a composite intermediate material in which an intermediate material for making an outer ring and an intermediate material for making an inner ring are integrated by forging, then the composite intermediate material is An invention is described in which an outer ring intermediate material for making an outer ring and an inner ring intermediate material for making an inner ring are divided. In the case of the invention described in Patent Document 1, an inner ring having a deep groove type inner ring raceway on the outer peripheral surface is obtained by expanding the diameter of a part of the intermediate material for the inner ring for making the inner ring. I have to.
Next, in Patent Document 2, a material formed by cutting a steel pipe made by hot extrusion is axially compressed (upsetting) with a vertical press, and a deep groove type is formed on the inner peripheral surface. An invention relating to a method for producing an outer ring having an outer ring raceway is described.

  Among the inventions described in Patent Documents 1 and 2 as described above, in the case of the invention described in Patent Document 1, a conical cylindrical portion is provided in the portion near the outer diameter of the material at the initial stage of processing. Form a composite intermediate material. For this reason, the processing load and the stress applied to the die including the punch and receiving die of the forging device are high when the composite intermediate material having a complicated shape including the conical cylindrical portion is comparatively large. Thus, the amount of elastic deformation of each part of the forging device including this mold is increased. As a result, it is difficult to sufficiently improve the dimensional accuracy and shape accuracy of the obtained composite intermediate material, the intermediate material for manufacturing the outer ring and the inner ring made from the composite intermediate material, and further the outer ring and the inner ring. In particular, when the process for producing the composite intermediate material is performed by cold forging, the load applied to the mold or the like becomes excessive, and it becomes difficult to ensure the durability of the mold or the like. Therefore, the processing of the composite intermediate material is made by hot forging or warm forging. In the case of hot forging or warm forging, the molds can be connected to each other regardless of the difference in temperature expansion. In order to ensure the fitting, the gap between the fitting portions must be set larger than in the case of cold forging. For this reason, it becomes difficult to sufficiently secure the shape and dimensional accuracy centered on the concentricity between the inner and outer diameters of the obtained composite intermediate material and the inner and outer peripheral surfaces. As a result, it is difficult to sufficiently secure the dimensional accuracy and run-out accuracy of the inner and outer diameters of the outer ring and inner ring obtained in the above-described applications that do not require a high degree of rotational accuracy.

  Moreover, in the case of the invention described in Patent Document 2, since the ring-shaped material is obtained by cutting a steel pipe made by hot extrusion, the inner and outer diameter dimensions and both inner and outer peripheral surfaces of this material are obtained. It is difficult to ensure a high degree of shape and dimensional accuracy centering on the concentricity between each other. As a result, it becomes difficult to ensure high dimensional accuracy and runout accuracy of the inner and outer diameters of the outer ring and inner ring obtained. Also, the work of cutting the steel pipe to make the material is troublesome, the productivity is poor, and the cost increases. Furthermore, it is necessary to perform cutting by decarburization on the material, and this also increases the cost.

  Patent Document 3 describes an invention in which a ring-shaped part is formed by cold-working a cylindrical material. However, in the case of the invention described in the above-mentioned Patent Document 3, only a single ring-shaped part is manufactured, and the axial dimension is not regulated during cold working, and the obtained ring The accuracy of the axial length of the shaped parts, and hence the accuracy of the volume, cannot be ensured. For this reason, it is difficult to make a practical race by simply plastically deforming the ring-shaped part.

  Furthermore, in Patent Document 4, a forging process is performed on the material to form an annular intermediate material with a crank-shaped cross section, and the intermediate material is cut and separated at the intermediate portion in the radial direction of the intermediate material. A method of making a pair of ring-shaped materials for making is described. In the case of such a method described in Patent Document 4, in the process of making both of these ring-shaped materials, the center portion of the intermediate material is punched out and the portion is scrapped. The part between the two ring-shaped materials is also punched into scrap. For this reason, the part which becomes a scrap increases among the said raw materials, and the yield of material worsens.

  On the other hand, the inventors of the present invention, for example, used a bearing that is used in the above-described applications and does not require a high degree of rotational accuracy, and that is configured with a radial ring bearing at a low cost while ensuring sufficient practical accuracy. The method of obtaining was considered (Japanese Patent Application No. 2004-289566). In the method according to the present invention, the race is produced by further cold-working a cylindrical high-precision ring made by cold working and having a volume substantially the same as the volume of the finished product. That is, the high-accuracy ring is further plastically deformed by cold working to process the surface shape including the raceway surface into substantially the same shape as the finished product.

FIG. 7 shows a process of making the inner ring 3a by cold working the high precision ring 8a.
In this case, first, the first intermediate material 9 shown in (B) is pressed by pressing a punch against the radially outer half of both axial end faces of the high-precision ring 8a shown in FIG. Get.
Next, an inner ring raceway 6 formed on the first intermediate material 9 with an outer diameter of a part in the radial direction (upper end portion in FIG. 7) formed on the outer peripheral surface of the intermediate portion of the inner ring 3a {FIG. 7F and FIG. No. 6} is applied to the groove bottom diameter (the outer diameter of the portion having the smallest outer diameter at the center in the width direction of the deep groove type inner ring raceway 6). A second intermediate material 10 is obtained.
Next, in the second intermediate material 10, the axial direction of the wall thickness in the radial direction of the portion corresponding to the other half part in the axial direction of the inner ring raceway 6 (the lower half part in FIG. 7) of the second intermediate material 10. The third intermediate material 11 shown in (D) is obtained by applying an inner diameter extrusion process for matching the distribution of the inner ring 3a to the distribution of the corresponding portion of the inner ring 3a to be manufactured.
Next, the inner diameter of the third intermediate material 11 is increased by extending the inner diameter of the third intermediate material 11 near the other end in the axial direction (near the lower end in FIG. 7). A fourth intermediate material 12 shown in (E) is obtained by making the inner ring raceway 6 uniform on the outer peripheral surface and making the inner ring raceway uniform.
Finally, the fourth intermediate material 12 is subjected to a finishing process such as a rolling process for adjusting the shape and properties of the outer peripheral surface to obtain an inner ring 3a shown in FIG.

FIG. 8 shows a process for manufacturing the outer ring 2a by cold-working the high-precision ring 8b.
In this case, first, a first intermediate material 9a shown in (B) is pressed by pressing a punch against the radially inner half of both axial end faces of the high-precision ring 8b shown in FIG. Get.
Next, the first intermediate material 9a is subjected to contraction processing for reducing the outer diameter of a part of the radial direction (the part excluding the upper end portion in FIG. 8) to the outer diameter of the outer ring 2a. The second intermediate material 10a shown in FIG.
Next, the second intermediate material 10a is formed with one half of the axial direction of the outer ring raceway 5 (the lower half of FIG. 8) of the second intermediate material 10a and the other half of the axial direction of the outer ring raceway 5 is formed. An inner diameter extrusion process is performed to match the distribution in the axial direction of the wall thickness in the radial direction of the portion corresponding to the portion (the upper half portion in FIG. 8) with the distribution of the corresponding portion of the outer ring 2a to be made (D The third intermediate material 11a shown in FIG.
Next, the outer diameter of the third intermediate material 11a near the other end in the axial direction of the third intermediate material 11a (near the upper end in FIG. 8) is reduced, and this outer diameter is removed (excluding the chamfered portions at both ends). The outer ring raceway 5 is formed on the inner peripheral surface, and the outer ring raceway forming process is performed to obtain the fourth intermediate material 12a shown in (E).
Finally, the fourth intermediate material 12a is subjected to a finishing process such as a rolling process for adjusting the shape and properties of the inner peripheral surface to obtain the outer ring 2a shown in FIG.

  As described above, if the outer ring 2a or the inner ring 3a of the radial ball bearing 1 is manufactured, the outer ring 2a or the inner ring 3a used in a portion where a high degree of rotational accuracy is not required can be achieved while ensuring practical accuracy. Can be built at a low cost. However, even in this case, the radial ball finally obtained that the dimensional accuracy including the shape accuracy and volume accuracy of the high-precision rings 8b and 8a to be the material of the outer ring 2a or the inner ring 3a is sufficiently secured. This is important in terms of ensuring the practical accuracy of the bearing. In order to further reduce the cost, it is preferable that the high-accuracy ring 8a for producing the inner ring 3a and the high-accuracy ring 8b for producing the outer ring 2a are produced from a single material. .

  On the other hand, in the case of the conventional methods described in Patent Documents 2 and 3, high-accuracy rings for making the respective race rings (inner ring 3a or outer ring 2a) are made independently of each other. This is not preferable from the viewpoint of reducing the cost by efficiently producing a high-precision ring for a wheel. In addition, Patent Document 5 describes a method of manufacturing a ring-shaped part by reversal processing that converts the cross-sectional shape of an annular material formed by punching a metal plate by 90 degrees. Even with the described method, it is impossible to efficiently produce a high-precision ring and reduce the cost.

  On the other hand, in the case of the conventional method described in Patent Document 1, it is good from the viewpoint of improving the efficiency of manufacturing work of the high-accuracy ring constituting each track ring and improving the yield of the material. However, there are problems in terms of ensuring the durability of the processing apparatus and ensuring the dimensional accuracy. Furthermore, in the case of the conventional method described in Patent Document 4, it is good from the viewpoint of improving the efficiency of the manufacturing work of the high-accuracy ring constituting each race, but as described above, securing the yield of the material. There is a problem from the aspect.

Japanese Patent Laid-Open No. 5-277615 Japanese Patent Laid-Open No. 2001-150082 JP 2000-94080 A JP 2000-71046 A Japanese Patent Laid-Open No. 10-146642

  In view of the circumstances as described above, the present invention is a material for producing an inner ring or an outer ring constituting a radial ball bearing by cold working, and sufficiently secures the practical accuracy of the finally obtained radial ball bearing. The present invention has been invented to realize a manufacturing method capable of easily and inexpensively manufacturing a high-accuracy ring that can be produced.

The method for producing a high-accuracy ring of the present invention includes at least the following steps (a) to (c).
(a) A billet-like material made of metal and having a volume larger than the volume of the high-precision ring to be manufactured is compressed in the axial direction, and a circular hole is formed in the central portion in the radial direction so that a predetermined thickness is formed in the central portion. A step of using a cylindrical portion having a vertical dimension and a predetermined axial dimension as a first intermediate material provided with an outward flange-like flange-like portion around the cylindrical portion.
(b) The first intermediate material is cut at the radial intermediate portion of the first intermediate material at the boundary between the outer peripheral surface of the cylindrical portion and the inner peripheral edge of the bowl-shaped portion, and obtained from the cylindrical portion. A portion to be obtained is a cylindrical first high-accuracy ring, and a portion obtained from the bowl-shaped portion is a ring-shaped second intermediate material.
(c) A cylindrical second high-accuracy ring whose inner diameter, outer diameter, and axial length are regulated values by reversal processing that changes the cross-sectional direction of the second intermediate material by 90 degrees; Process.

According to the manufacturing method of the high-accuracy ring of the present invention configured as described above, the inner diameter, the outer diameter, and the axial dimension are restricted to appropriate values, and the central axis of the inner peripheral surface and the central axes of the outer peripheral surface are connected to each other. A high-accuracy ring closely matched can be manufactured easily and efficiently with good material yield. As a result, it is possible to reduce the processing cost of the outer ring and inner ring constituting the radial ball bearing, which is manufactured by processing this high-accuracy ring, while ensuring practically sufficient performance.
Of course, by improving the machining accuracy, the present invention can be applied to a high-accuracy ring used for manufacturing a bearing ring for a ball bearing that requires a higher accuracy than the above-described applications. It is.

In the case of carrying out the present invention, preferably, as described in claim 2, for example, in the step (a), the axially opposite ends of the material are compressed in a direction approaching each other so A boss portion having a thickness dimension larger than that of the radially outward portion is formed, and a hook-like portion is formed around the boss portion. Then, the central portion of the boss portion is crushed in the axial direction to reduce the thickness of the central portion in the axial direction, and the thickness in the axial direction of the portion near the outer diameter of the boss portion is increased. Next, a circular hole is formed by punching out the portion where the thickness of the central portion is reduced.
By adopting such a configuration, it is possible to easily perform the punching work of the circular hole, and to reduce the volume of the portion to be scraped by the punching process, thereby further increasing the material yield. Can be improved.

Preferably, when the present invention is carried out, as described in claim 3, for example, in the step (a), the central portions of both end surfaces in the axial direction of the material are compressed in a direction approaching each other, and the shaft of the central portion is compressed. By reducing the thickness with respect to the direction, a pair of elementary cylindrical portions projecting in the axial direction (directions opposite to each other) from both side surfaces in the axial direction of the bowl-shaped portion are formed. And the part which reduced the thickness of the said center part is punched out, and a circular hole is formed.
By adopting such a configuration, it is possible to easily perform the punching work of the circular hole, and reduce the volume of the portion to be scraped by the punching process, thereby increasing the material yield. It can be further improved.

Further, when the present invention is carried out, preferably, the outer peripheral edge of the second intermediate material is placed between the second intermediate material between the step (b) and the step (c). In a state where the outer diameter of the material is restricted so as not to expand, an upsetting process is performed in which the second intermediate material is compressed to a predetermined thickness in the axial direction. Then, after the surplus portion of the second intermediate material is flowed to the inner peripheral edge, the inner peripheral portion is removed by piercing to remove the surplus portion, thereby reducing the volume of the second intermediate material. Set to desired value.
By adopting such a configuration, the volume of the second intermediate material can be more strictly regulated.

  When the present invention is implemented, preferably, the thickness dimension in the axial direction of the hook-shaped portion formed in the step (a) is set closer to the radial center portion (for example, the boss portion). The smaller it is, the smaller it is toward the outer periphery. Then, in the step (c), the outer intermediate portion of the second intermediate material is contracted radially inward, and the reverse processing is performed in the same direction in which the inner peripheral portion is expanded radially outward. If comprised in this way, the thickness dimension regarding the radial direction of the cylindrical 2nd high precision ring obtained from this 2nd intermediate material is restrained about an axial direction, keeping the stress applied to each part of the above-mentioned 2nd intermediate material low. Can be uniform.

  1 to 4 show a first embodiment of the present invention corresponding to claims 1, 2, 4, and 5. In the field of press working such as plastic working including cold forging and punching, if the shape before processing and the shape after processing are known, the shape and structure of the mold used for plastic processing can be determined. It is often easy (understood) to understand. Accordingly, illustrations of the shapes and structures of some of the molds are omitted, and the following description will focus on the shape of the workpiece in each process. In addition, since FIG. 1 is drawn with the postures of the workpieces matched to make it easy to understand the progress of the machining, the vertical direction of the workpieces in each process is not necessarily the same as the drawings. do not do. As is well known in the field of press working, it is natural to place the pressing die upward and the receiving die receiving the pressing force via the workpiece below.

  In the present embodiment, first, a long wire is cut into a predetermined length to obtain a billet (columnar material) 13 as shown in FIG. The billet 13 has a length that is slightly larger than the total volume of the first and second high-precision rings 14 and 15 to be obtained while pulling out the long wire wound around the drum from the uncoiler. It is obtained by cutting into dimensions (the above-mentioned predetermined length).

  The billet 13 thus obtained has a beer barrel-shaped (first) as shown in FIG. 1B by correcting both axial end surfaces by applying cold upsetting. 1) Preliminary intermediate material 16 is used. Thereafter, the preliminary intermediate material 16 is further subjected to an upsetting process that compresses in the axial direction, thereby obtaining a disk-shaped second preliminary intermediate material 17 as shown in FIG. The second preliminary intermediate material 17 has a boss portion 18 having a thickness dimension in the axial direction larger than that of a radially outer portion at the radial center portion, and an outward flange-like flange shape around the boss portion 18. The portions 19 are formed concentrically with each other.

In the second preliminary intermediate material 17, the thickness dimension T ₁₈ of the central boss portion ₁₈ is the largest with respect to the thickness dimension in the axial direction, and the thickness dimensions t ₁ and t ₂ of the bowl-shaped portion 19 are is smaller _{(T 18> t 1> t} 2) than the thickness T ₁₈ parts 18. Furthermore, the cross-sectional shape of the hook-shaped portion 19 is a wedge shape, and the thickness dimensions t ₁ and t ₂ of the hook-shaped portion 19 gradually change in the radial direction. That is, the thickness dimension t _1, t ₂ of the flange portion 19, the thickness t ₁ of the inner peripheral edge portion is large, the thickness t ₂ of the outer peripheral edge portion is smaller. The said hook-shaped part 19 is a part which should become the 2nd high precision ring 15 for making the outer ring | wheel 3a {refer (F) of FIG. 8} among said 1st and 2nd high precision rings 14 and 15. but the thickness T ₁₅ of the second high-precision ring 15 to produce {see FIG. 2 (C)}, the thickness dimension t ₁ of the inner and outer periphery of the flange portion 19, t ₂ of the intermediate (t ₁ > T ₁₅ > t ₂ ).

When performing the upsetting process to form the second preliminary intermediate material 17 as described above, the preliminary intermediate material 16 is a pair of gold having an inner surface shape that matches the outer surface shape of the second preliminary intermediate material 17. Compress between the molds in the axial direction. That is, the preliminary intermediate material 16 has the same inner diameter as the outer diameter D _{17 of} the second preliminary intermediate material 17, and the shape of the bottom surface is one side surface of the second preliminary intermediate material 17 in the axial direction {FIG. ) In a shape matching the shape of the bottom surface} with a bottomed circular hole, with the central axis of the preliminary intermediate material 16 and the central axis of the circular hole being matched, The preliminary intermediate material 16 is compressed in the axial direction between the bottom surface of the circular hole and the front end surface of the pressing die (a flat surface in this embodiment). Since the shape of the bottom surface and the front end surface is a shape that matches both axial side surfaces of the second preliminary intermediate material 17 (the concave and convex directions are reversed), the bottom surface and the front end surface are strongly pressed against each other. Thus, the second preliminary intermediate material 17 can be obtained.

The second preliminary intermediate material 17 is subjected to a second upsetting process by crushing the central portion of the boss portion 18 in the axial direction, so that the third preliminary intermediate material as shown in FIG. The material 20 is used. For this purpose, the center surface of the boss portion 18 of the second preliminary intermediate material 17 is restrained so that the outer diameter of the boss portion 18 does not expand, while the front end surface {the lower surface of FIGS. 1C and 1D}. Press in the axial direction from the side. At this time, the hook-shaped portion 19 of the second preliminary intermediate material 17 is sandwiched between the receiving mold and the holding mold to prevent the hook-shaped portion 19 from being deformed. Of these, the receiving mold includes a bottomed circular hole having the same inner diameter as the outer diameter D _{17 of} the second preliminary intermediate material 17 (and the third preliminary intermediate material 20). It has a cylindrical shape having an outer diameter that can be inserted inside the circular hole without a gap and an inner diameter that can fit the boss portion 18 inside without a gap. In addition, a punch unit is installed inside the holding die so as to be capable of axial displacement. This punch unit has a cylindrical press having an outer diameter smaller than the outer diameter of the boss 18 inside a cylindrical holding cylinder (ring punch) having an outer diameter that matches the outer diameter of the boss 18. A punch (punch) is fitted inside so as to be axially displaceable. And the front end surface of the said control cylinder is used as the annular | circular shaped control surface. The positional relationship of the receiving mold with respect to the workpiece is opposite to that in the case of producing the second preliminary intermediate material 17 with respect to the axial direction.

When the second preliminary intermediate material 17 is used as the third preliminary intermediate material 20, the hook-shaped portion 19 of the second preliminary intermediate material 17 is sandwiched between the receiving mold and the holding mold, and the punch With the front end surface of the holding cylinder of the unit being fixed at an appropriate position, the pressing rod of the punch unit is pressed against the front end portion of the boss portion 18. This pressing operation is performed until a part of the boss portion 18 reaches the distal end surface of the holding cylinder, there is no more space for the metal material to flow, and the pressing rod can no longer be displaced. As a result, the thickness in the axial direction of the central portion of the boss portion 18 is reduced, and the thickness in the axial direction of the portion near the outer diameter of the boss portion 18 is increased. A cylindrical portion 21 whose size is regulated to a desired value is formed. Regarding the third preliminary intermediate material 20 obtained in this way, the length L ₂₁ from the base end surface of the third preliminary intermediate material 20 (upper surface in FIG. 1D) to the distal end surface of the cylindrical portion _21. Is as specified. Further, the thickness T ₂₁ in the radial direction of the cylindrical portion 21 is strictly regulated to ½ of the difference between the inner diameter of the holding die and the outer diameter of the pressing rod of the punch unit. In short, the volume error existing in the second preliminary intermediate material 17 is compensated by changing the thickness of the bottom plate portion remaining in the central portion of the boss portion 18 (collecting the volume error in a scrap portion).

  When the third preliminary intermediate material 20 is formed as described above, it is surrounded by the cylindrical portion 21 at the center of the third preliminary intermediate material 20 as shown in FIG. A circular hole 22 is formed in the portion by punching with a press to obtain a first intermediate material 23 having a cylindrical portion 24 in the center. In this punching process, the cylindrical portion 21 is inserted by a punching punch inserted on the inner diameter side of the cylindrical portion 21 in a state where the third preliminary intermediate material 20 is placed on a receiving die having a punched hole in the center. The portion surrounded by is punched as a disc-like scrap 25. The outer diameter of the punching punch and the inner diameter of the punching hole are regulated so that the inner diameter of the circular hole 22 matches the inner diameter of the cylindrical portion 21. Therefore, the inner peripheral surface of the cylindrical portion 24 of the first intermediate material 23 obtained as a result of the punching process is a single cylindrical surface.

  The first intermediate material 23 obtained in this way is, as shown in FIG. 1 (F), a radial intermediate portion between the outer peripheral surface of the cylindrical portion 24 and the inner peripheral edge of the bowl-shaped portion 19. The first high precision ring 14 and the second intermediate material 27 are obtained by cutting at the boundary portion. This cutting operation is performed in such a manner that one axial surface {the lower surface of FIG. The surface {the upper surface of Fig. 1 (F)} is pressed by a punching punch toward the receiving mold. As a result of such cutting work by punching, the portion obtained from the cylindrical portion 24 becomes the cylindrical first high-accuracy ring 14, and the portion obtained from the bowl-shaped portion 19 is an annular second shape. It becomes the intermediate material 27.

  Of the first high-accuracy ring 14 and the second intermediate material 27 obtained in this way, the first high-accuracy ring 14 is obtained by, for example, the process shown in FIG. By using the ring 14 as the high-precision ring 8a shown in FIG. 7), the inner ring 3a is made. On the other hand, the second intermediate material 27 is formed into the second high-accuracy ring 15 by the processes as shown in FIGS. 15 is used as the high-precision ring 8b shown in FIG. 8), and the outer ring 2a is made.

  In the step of using the second intermediate material 27 as the second high-accuracy ring 15, first, the second intermediate material 27 is placed in the circular hole 30 of the die 29 as shown in FIG. A so-called sizing process is performed in which the tip ends of the pair of punches 31 and 31 are strongly pressed in a tightly fitted state. The front end surfaces of both punches 31 and 31 are conical concave surfaces that are in close contact with both axial side surfaces of the second intermediate material 27. The punches 31, 31 having the respective tip surfaces in such a shape reduce the distance between the tip surfaces to an appropriate distance while compressing the second intermediate material 27 in the axial direction. The thickness of the intermediate material 27 is set to an appropriate value. At this time, the surplus meat that has flowed as the thickness of the second intermediate material 27 is set to an appropriate value is collected at the inner peripheral edge of the second intermediate material 27. Accordingly, if the circular hole 32 is formed by punching (piercing) as shown in FIG. 2B in the center of the second intermediate material 27 subjected to the sizing, the second high material to be produced is formed. A fourth preliminary intermediate material 33 having the same volume as that of the precision ring 28 is obtained.

After the fourth preliminary intermediate material 33 is formed, the outer diameter portion of the fourth preliminary intermediate material 33 is changed from the state shown in FIG. 2B to the state shown in FIG. Reversing is performed by shrinking inward in the direction and changing the direction of the cross section by 90 degrees in the same manner as expanding the portion closer to the inner diameter outward in the radial direction. As shown in FIG. 4, the reversal process is performed by pushing the fourth preliminary intermediate material 33 into the cylindrical die 34 with a punch 35. The die 34 has a central hole in which a large-diameter portion 36 provided on the opening side and a small-diameter portion 37 concentric with the large-diameter portion 36 provided on the back side are continuous by a curved surface 38. . Among these, the inner diameter R ₃₇ of the small diameter portion 37 is smaller than the outer diameter of the fourth preliminary intermediate material 33 and larger than the inner diameter. The punch 35 has a tapered portion at the tip. When performing the reversing process, first, as shown in FIG. 4A, the fourth preliminary intermediate material 33 is locked (set) inside the large-diameter portion 36. Next, as shown in FIGS. 4B and 4C, the fourth preliminary intermediate material 33 is pushed into the small diameter portion 37 by the punch 35. As a result, the cross-section of the fourth preliminary intermediate material 33 is inverted by 90 degrees, and the cylindrical second high-accuracy ring 15 as shown in FIG.

Along with the reversing process performed as described above, the portion closer to the inner diameter of the fourth preliminary intermediate material 33 is stretched to reduce the thickness dimension, and the portion closer to the outer diameter is also compressed to increase the thickness dimension. Become. On the other hand, in the case of the present embodiment, since the thickness dimension in the axial direction of the fourth preliminary intermediate material 33 is large at the inner diameter portion and small at the outer diameter portion, the reversing process is completed. The thickness of the second high-accuracy ring 15 obtained in the radial direction is uniform in the axial direction (except for the chamfered portions at both end edges). That is, the fourth preliminary intermediate material 33 becomes the cylindrical second high-accuracy ring 15 in which the inner diameter, the outer diameter, and the axial length are set as the regulation values after the reversing process is completed. For this reason, the difference between the inner diameter R ₃₇ and the outer diameter D ₃₅ of the previous half of the punch 35 of the small-diameter portion 37, the second high-precision ring 15 to make the thickness T ₁₅ {shown in FIG. 2 (C) 2} (R ₃₇ −D ₃₅ = 2T ₁₅ ). The second high precision ring 15 as described above is subjected to cold working as shown in FIG.

  FIG. 5 shows Embodiment 2 of the present invention corresponding to claims 1 and 3 to 5. In the case of the present embodiment, the shape of the outer peripheral surface and both ends in the axial direction is formed on the (first) preliminary intermediate material 16 {see FIG. 5B) manufactured in the same manner as in the case of the first embodiment described above. By performing plastic working for trimming, a second preliminary intermediate material 39 as shown in FIG. 5C is obtained. The second preliminary intermediate material 39 is formed with circular concave holes 40a and 40b having the same diameter and concentric with each other in the center portion of both axial end surfaces, and at one axial end {upper end in FIG. 5C}. The outer diameter is made smaller than other parts.

  In the case of the present embodiment, a disk-shaped third preliminary intermediate material as shown in FIG. 5D is obtained by subjecting such a second preliminary intermediate material 39 to an upsetting process that compresses in the axial direction. 41 is obtained. The third preliminary intermediate material 41 includes a boss portion 42 and a bowl-shaped portion 19. Among these, the boss portion 42 provided in the central portion in the radial direction has a cylindrical shape in which the intermediate portion in the axial direction is blocked by the partition plate portion 43, and the thickness dimension in the axial direction is larger than that in the radially outward portion. It has become. Further, the hook-shaped portion 19 is formed concentrically with the boss portion 42 around the boss portion 42. The thickness dimension of the bowl-shaped portion 19 is regulated in the same manner as in the case of the first embodiment.

In the upsetting process for forming the third preliminary intermediate material 41 as described above, the second preliminary intermediate material 39 is basically replaced with the third preliminary intermediate material 41 in the same manner as in the first embodiment. It is performed by compressing in the axial direction between a pair of molds having an inner surface shape that matches the outer surface shape. In particular, in the case of the present embodiment, in the state where these two molds are brought close to each other until the distance between the two molds reaches a predetermined value, the center of one or both molds is attached to the mold. A punch provided with axial movement is strongly pressed against the central portion of the third preliminary intermediate material 41, which is the workpiece, to reduce the thickness of the central portion. And while reducing the thickness regarding the axial direction of the center part of the said boss | hub part 42, a metal material is made to flow from this center part, and a metal material is completely filled between the said both metal mold | dies. As a result, the axial length L _{42 of the} boss portion 42 and the thickness dimension of the flange-shaped portion 19 in the axial direction become the prescribed values. This is because the two molds are stopped in a state in which the distance between the two molds becomes a predetermined value. Further, the thickness of each part of the boss portion 42 in the radial direction is strictly regulated to ½ of the difference between the inner diameters of the two molds and the outer diameter of the punch (or part of the mold). The In short, the volume error of the second preliminary intermediate material 39 is compensated by making the thickness of the partition plate portion 43 at the intermediate portion in the axial direction of the boss portion 42 different.

  If the third preliminary intermediate material 41 is formed as described above, as shown in FIG. 5E, the axial intermediate portion of the boss portion 42 is formed at the center of the third preliminary intermediate material 41. The partition plate portion 43 is removed by punching with a press to form a circular hole 44, and a first intermediate material 46 having a cylindrical portion 45 at the center is obtained. In this punching process, the third preliminary intermediate material 41 is placed on a receiving die having a surface shape that matches one axial side surface of the third preliminary intermediate material 41 and having a punched hole in the center. Then, the partition plate portion 43 is punched out as a disc-shaped scrap 25 by a punching punch inserted on the inner diameter side of the boss portion 42. The outer diameter of the punching punch is matched with the inner diameter of the boss portion 42, and the inner peripheral surface of the first intermediate material 46 obtained as a result of the punching process is a single cylindrical surface.

  The first intermediate material 46 obtained in this way is, as shown in FIG. 5F, a radial intermediate portion between the outer peripheral surface of the cylindrical portion 45 and the inner peripheral edge of the bowl-shaped portion 19. The first high precision ring 47 and the second intermediate material 27 are obtained by cutting at the boundary portion. This cutting operation is performed in such a manner that one axial surface (the lower surface in FIG. 5F) of the bowl-shaped portion 19 is supported by the upper surface of the annular receiving die, and the axial direction in the central portion of the first intermediate material 46 and the like. The surface {the upper surface in FIG. 5F} is formed by strongly pressing the front end surface toward the receiving die with a punching punch having a shape matching the other surface of the central portion. As a result of such cutting work by punching, the portion obtained from the cylindrical portion 45 becomes the first high-accuracy ring 47 having a cylindrical shape and stepped portions 48, 48 on the outer peripheral surfaces of both ends. The part obtained from 19 becomes the annular second intermediate material 27.

  Of the first high-accuracy ring 47 and the second intermediate material 27 obtained in this way, the first high-accuracy ring 47 is obtained by, for example, the process shown in FIG. By using the ring 47 as the first intermediate material 9 shown in FIG. 7, the inner ring 3a is made. On the other hand, the second intermediate material 27 is formed as the second high-accuracy ring 15 by the processes as shown in FIGS. 2 to 4 as shown in FIG. The outer ring 2a is manufactured by such a process (by using the second high precision ring 15 as the high precision ring 8b shown in FIG. 8).

  The feature of the present invention is that, for example, a pair of high-precision rings for producing an inner ring and an outer ring can be efficiently produced. The method for processing the obtained high-accuracy ring into an inner ring or an outer ring is not particularly limited.

Sectional drawing which shows the front | former stage of the manufacturing process of Example 1 of this invention. Sectional drawing which similarly shows a back | latter stage. Sectional drawing which shows the specific implementation condition of a sizing process. Sectional drawing which similarly shows the implementation condition of inversion processing. Sectional drawing which shows the manufacturing process of Example 2 of this invention. The partial cutaway perspective view which shows an example of the radial ball bearing which incorporated the inner ring | wheel and outer ring | wheel produced with the high precision ring used as the object of this invention. Sectional drawing which shows an example of an inner ring process. Sectional drawing which shows an example of an outer ring process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Radial ball bearing 2, 2a Outer ring 3, 3a Inner ring 4 Ball 5 Outer ring raceway 6 Inner ring raceway 7 Cage 8, 8a, 8b High precision ring 9, 9a First intermediate material 10, 10a Second intermediate material 11, 11a Third Intermediate material 12, 12a Fourth intermediate material 13 Billet 14 First high-accuracy ring 15 Second high-accuracy ring 16 Preliminary intermediate material 17 Second preliminary intermediate material 18 Boss portion 19 Hook-shaped portion 20 Third preliminary intermediate material 21 Cylindrical portion 22 circular hole 23 first intermediate material 24 cylindrical portion 25 scrap 27 second intermediate material 29 die 30 circular hole 31 punch 32 circular hole 33 fourth preliminary intermediate material 34 die 35 punch 36 large diameter portion 37 small diameter portion 38 curved portion 39 first Two preliminary intermediate materials 40a, 40b Circular concave holes 41 Third preliminary intermediate material 42 Boss portion 43 Partition plate portion 44 Circular hole 45 Cylindrical portion 46 First During material 47 first precision ring 48 stepped portion

Claims (5)

A method for manufacturing a high-accuracy ring, comprising at least the following steps (a) to (c):
(a) A billet-like material made of metal and having a volume larger than the volume of the high-precision ring to be manufactured is compressed in the axial direction, and a circular hole is formed in the central portion in the radial direction so that a predetermined thickness is formed in the central portion. A step of using a cylindrical portion having a vertical dimension and a predetermined axial dimension as a first intermediate material provided with an outward flange-like flange-like portion around the cylindrical portion.
(b) The first intermediate material is cut at the radial intermediate portion of the first intermediate material at the boundary between the outer peripheral surface of the cylindrical portion and the inner peripheral edge of the bowl-shaped portion, and obtained from the cylindrical portion. A portion to be obtained is a cylindrical first high-accuracy ring, and a portion obtained from the bowl-shaped portion is a ring-shaped second intermediate material.
(c) A cylindrical second high-accuracy ring whose inner diameter, outer diameter, and axial length are regulated values by reversal processing that changes the cross-sectional direction of the second intermediate material by 90 degrees; Process.   In the step (a), by compressing both end portions in the axial direction of the material in a direction approaching each other, a boss portion having a thickness dimension in the axial direction larger than that in the radially outer portion is formed in the central portion in the radial direction. A hook-shaped part is formed in the peripheral part of the boss part, and the central part of the boss part is crushed in the axial direction to reduce the thickness of the central part in the axial direction and the outer diameter of the boss part. 2. The method for manufacturing a high-accuracy ring according to claim 1, wherein a circular hole is formed by punching out the portion where the thickness of the central portion is reduced after increasing the thickness of the offset portion in the axial direction.   In the step (a), by compressing the central portions of both end surfaces in the axial direction of the material in a direction approaching each other to reduce the thickness of the central portion in the axial direction, the axial portions are axially moved from both axial sides of the bowl-shaped portion. The method for manufacturing a high-accuracy ring according to claim 1, wherein after forming the protruding cylindrical portion, a circular hole is formed by punching out the portion where the thickness of the central portion is reduced.   Between the step (b) and the step (c), the outer periphery of the second intermediate material is constrained so that the outer diameter of the second intermediate material does not increase. In the direction, the upsetting process is performed to compress to the predetermined thickness, and after the surplus part of the second intermediate material flows to the inner peripheral part, the inner peripheral part is removed by piercing to remove the surplus part. The manufacturing method of the high precision ring described in any one of Claims 1-3 provided with the process of making the volume of said 2nd intermediate material into a desired value by removing. The thickness dimension in the axial direction of the bowl-shaped portion formed in the step (a) is reduced toward the outer peripheral edge greatly toward the central portion in the radial direction, and the outer diameter of the second intermediate material is reduced in the step (c). 5. The method for manufacturing a high-accuracy ring according to claim 1, wherein the shift portion is contracted radially inward and the reversal process is performed in a direction in which the radially close portion is expanded radially outward.

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