JPH079064A - Manufacture of outer race for ball bearing - Google Patents

Abstract

PURPOSE:To provide a method for manufacturing an outer race for ball bearing enable to obtain the outer race for ball bearing having excellent durability. CONSTITUTION:After heating a columnar state billet 1 having a first prescribed height H forming plural metal flows 2 in the axial direction of the cross section, an upsetting is executed to manufacture a first upsetting processed material. Successively, after turning over the first upsetting processed material, the upsetting is again applied to manufacture a second upsetting processed matrial 5 having a prescribed height H2. Thereafter, by applying a vertically uniform center pressing, center punching and rolling work (V1) respectively, then the width upset is executed to manufacture the finish forging product 17 having a third prescribed height H3. Further, the upsetting ratio being the ratio of the decreasing quantity (H-H3) to the first prescribed hesight H of the columnar steel billet 1 is made to be 0.50-0.65.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an outer ring for a ball bearing, and more particularly to a method for manufacturing an outer ring for a ball bearing, which is manufactured by plastic working an outer ring for a ball bearing used for aircraft engines and the like.

[0002]

2. Description of the Related Art When an outer ring for a ball bearing is manufactured by plastic working, conventionally, a cylindrical steel billet is held by an upper mold and a lower mold, and the cylindrical steel billet is upset. After press-pressing the center portion of the plane from above to reduce the thickness of the center portion of the plane, punching is performed to punch the inside to manufacture a ring-shaped workpiece, and then the ring-shaped workpiece is manufactured. The outer ring was manufactured by holding the outer peripheral surface of the above with a forming roll, rolling with a mandrel roll, and then cutting by machining.

[0003]

In the above conventional manufacturing method, the cylindrical steel billet is heated and then set up, but the lower die is heated more than the upper die. Since the contact time of the steel billet is long, the temperature distribution is not uniform, and the temperature becomes lower as it goes downward. Therefore, when the upsetting step is performed once as in the conventional manufacturing method, as shown in FIG. 4, the metal fiber flow after upsetting due to the flow resistance of the steel billet (hereinafter,
.., which are simply referred to as "metal flow", are asymmetrical in the vertical direction. Further, since the middle pressing is performed from one direction, the asymmetrical shape of the metal flows 51 ... Is increased. For this reason, the metal flow 51 of the work does not match the raceway surface of the bearing outer ring when the rolling process is finally performed, and the metal flow 51 ... Is cut when the work is formed by machining. There is a problem that the bearing life is shortened by being exposed on the outer ring raceway surface.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method of manufacturing an outer ring for a ball bearing, which can obtain an outer ring for a ball bearing having excellent durability.

[0005]

In order to achieve the above object, a method of manufacturing an outer ring for a ball bearing according to the present invention is provided with a first predetermined height H in which a large number of metal flows are formed in the axial direction of a cross section.
After heating the cylindrical steel billet with the hot forging zone,
Upsetting to produce an upset workpiece, then inverting the first upset workpiece, and then upsetting the first upset workpiece to have a second predetermined height H2. An upset product is manufactured, and thereafter, a flat central portion of the second upset product is evenly pressed from above and below to form an intermediate pressing portion, and then the intermediate pressing portion is hollowed out. Forming a ring-shaped workpiece, rolling the ring-shaped workpiece, then performing width upsetting to form a third upset workpiece having a third predetermined height H3, and Height reduction amount of the cylindrical steel billet with respect to the first predetermined height H of the cylindrical steel billet (H−
The upsetting rate, which is the ratio of H3), is set to 0.50 to 0.65.

[0006]

According to the above method, the first upset product manufactured by upsetting the heated cylindrical billet is inverted, and upset is performed again to form the second upset product. Since it is manufactured, it is possible to maintain the thermal symmetry of the product (the second upsetting work), and the ring-shaped work formed by middle pressing and hollowing is formed in the axial direction of the metal flow. The symmetry of can be secured.

By the way, when the first upset work is upset until the second upset work reaches the height of the final forged product, the ring-shaped work is higher than the upset work. Since the height is maintained, the ratio of the width T to the height H2 'of the ring-shaped workpiece 40, that is, the value of (T / H2') may increase as shown in FIG.

As described above, the so-called surface rolling in which the work is not plastically deformed to the inside of the ring-shaped workpiece 40 even if the rolling is performed in a state where the value of (T / H2 ') is relatively large, only the surface is plastically deformed. The rolling process ends in this state (surface rolling state).

Therefore, according to the present invention, the height H3 of the final forged product is
Rolling process is performed on the ring-shaped workpiece 40 having the second predetermined height H2 before it becomes the final forged product having the predetermined height H3 (third upsetting workpiece).
Since it is formed, it is possible to plastically deform the inside of the ring-shaped workpiece to give a desired curvature to the metal flow inside the workpiece, and to match the raceway surface shape of the outer ring with the metal flow. It will be possible.

Further, the height of the steel billet before installation (first
H), the height (third predetermined height) of the third upset workpiece that is the final forged product is H3, and the upsetting rate η is defined by the mathematical expression (1), then η = (H-H3) / H
(1) When the upsetting ratio η is small, the metal flow 42 has a small curvature, and as shown in FIG. 4A, after the width upsetting, the metal flow 42 ... The curvature is too small to match the raceway surface. On the other hand, when the upsetting ratio η is large, as shown in FIG.
Has a large curvature, and after the end of the width upsetting, the metal flow 42, ... At a place corresponding to the raceway surface has an excessively large curvature and does not match the raceway surface. Therefore, the upset ratio η has an optimum range. In the present invention, the upsetting ratio η is set to 0.
Since it is set to 50 to 0.65, it is possible to form a metal flow that matches the raceway surface of the outer ring.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings.

1 (I)-(V) and 2 (VI)-(VI)
II) is a manufacturing process chart sequentially showing one embodiment of a method for manufacturing an outer race for a ball bearing according to the present invention. The manufacturing process diagram is most suitable for manufacturing the outer ring of the ball bearing for an aircraft engine using the high temperature bearing material M50.

Each figure shows an outline of a cross section in the axial direction (vertical direction in the figure) of a steel billet which is a work during the manufacturing process, and the one-dot chain line shows the central axis.

In FIG. 1 (I), reference numeral 1 denotes a cylindrical steel billet having a height H of 143 mm (hereinafter simply referred to as "steel billet") formed from a material made by forging. Metal flows 2 are formed and are stretched in parallel with the axial direction of the steel billet 1.

In this manufacturing method, first, the steel billet 1 is heated to a hot forging zone, and then, as shown in FIG. 1 (II), a first upper mold 3a and a first lower mold 3b are used. Detained,
The first upsetting is performed by pressing from above with a predetermined pressure to produce a first upsetting 4 having a height H1 of, for example, 110 mm, and then the first upsetting 4 is inverted. , Figure 1
As shown in (III), the first upper mold 3a and the first lower mold 3b are held again, and the second upsetting is performed so that the height H2 is larger than the height of the final finished product. For example, a second upset workpiece 5 of 77 mm is manufactured.

That is, in the hot forging process as in this embodiment, as described in the section [Problems to be solved by the invention], the upper die 3a of the first upsetting is the first installation. Since the contact time with the steel billet 1 is longer than that of the lower die 3b, the temperature distribution inside the steel billet 1 becomes non-uniform and the temperature becomes lower as it goes downward, so the upsetting process is performed twice. Separately, by inverting the workpiece (workpiece) between the first upsetting and the second upsetting, it is possible to avoid the metal flow 2 ... Asymmetrical due to the non-uniformity of the temperature distribution. is doing.

Next, the second upset workpiece 5 is turned over again, and as shown in FIG. 1 (IV), the second upset work is performed by the second upper die 7a and the second lower die 7b. The center portion of the plane of the workpiece 5 is held and pressed with a predetermined uniform pressure in the arrow A direction and the arrow B direction to perform intermediate pressing, and the thickness of the central portion is reduced to form the intermediate pressing portion 9. Then, as shown in FIG. 1 (V), the through hole 10 is formed by punching out by punching or the like.
The ring-shaped processed product 11 in which is formed is molded.

Next, as shown in FIG. 2 (VI), the pressing surface 1
The outer periphery of the ring-shaped workpiece 11 is held by a forming roll 13 having 2 and the inner peripheral surface of the ring-shaped workpiece 11 is pressed by the mandrel roll 14 in the direction of arrow C to enlarge the hole diameter of the through hole 10. Then, the rolling process ends when the hole diameter reaches a predetermined value.

After the rolling process is performed in this manner, then, as shown in FIG. 1 (VII), the periphery of the work is held by the outer mold 15, and the upper surface of the work is held by the inner mold 16. The upsetting ratio η defined by the mathematical expression (1) is 0.50 to 0.
The width upsetting is performed so as to be within the range of 65, and the third upset work 17 which is the final forged product is manufactured.

Η = (H−H3) / H (1) Here, H3 is the height of the upsetting work 17 in the third upsetting. In this embodiment, H3 = 60 mm, and therefore the upset ratio η is set to 0.58 according to the mathematical expression (1).

That is, by setting the upsetting ratio η to a predetermined range (0.50 to 0.65) of 0.58 for the reason described in the section [Operation], the outer ring raceway surface 19 (see FIG. (See (VIII)) Metal flow 2 that matches the shape ...
Is formed.

Finally, as shown in FIG. 2 (VIII), an outer ring 18 having a metal flow 2 ... Which is cut out by machining to match the shape (curvature) of the raceway surface 19 is obtained. The outer ring 18 manufactured in this manner can prevent the cut surface of the metal flow 2 ... from being exposed to the raceway surface (prevention of end flow), can prolong the life of the outer ring 18, and can improve the bearing performance. The durability can be improved.

It is needless to say that the present invention is not limited to the above-mentioned embodiment and can be modified within the scope not departing from the gist. For example, if the cooling effect of the object to be processed is large, it goes without saying that the object to be processed may be reheated between the respective steps and each predetermined step may be performed. Moreover, FIG.
In order to make the flow vertically symmetrical, it was stated that after the first upsetting, it is inverted and then the second upsetting, but there is no effect on having a metal flow 2 that matches the shape of the raceway surface in VIII of FIG. If it is asymmetric (acceptable), the first upsetting step may be omitted (because the billet temperature can be prevented from decreasing and reheating can be reduced).

[0024]

As described in detail above, in the method for manufacturing the outer ring for the ball bearing according to the present invention, the cylindrical steel billet having the first predetermined height H in which a large number of metal flows are formed in the axial direction of the cross section. Is heated to a hot forging zone to perform upsetting to produce an upset workpiece, and then the first upset workpiece is inverted and then the first upset workpiece is upset to 2 predetermined height H2
And then pressurizing the center portion of the plane of the second upsetting work piece from above and below to form an intermediate pressing portion, and then punching out the intermediate pressing portion. To form a ring-shaped processed product, and then subject the ring-shaped processed product to rolling processing, and then performing width upsetting to obtain a third predetermined height H3.
Since the third upsetting work having the above is formed, the symmetry of the metal flow can be secured, and the outer ring having the metal flow relatively well matched with the raceway surface shape can be manufactured, and the durability of the bearing can be improved. It is possible to improve the property.

Further, the height decrease amount (H) of the cylindrical steel billet with respect to the first predetermined height H of the cylindrical steel billet.
Since the upsetting ratio, which is the ratio of −H3), is set to 0.50 to 0.65, it is possible to obtain an outer ring having a metal flow with a bending ratio substantially the same as that of the raceway surface.

[Brief description of drawings]

FIG. 1 is a manufacturing process diagram (1/2) showing an embodiment of a method for manufacturing an outer race for a ball bearing according to the present invention.

FIG. 2 is a manufacturing process diagram (2/2) showing an embodiment of a method for manufacturing an outer race for a ball bearing according to the present invention.

FIG. 3 is a diagram for explaining the relationship between the width T and the height H2 ′ of the ring-shaped workpiece.

FIG. 4 is a cross-sectional view of a workpiece showing a state of metal flow after upsetting in the related art.

[Explanation of symbols]

 1 Cylindrical Steel Billet 2 Metal Flow 4 First Upset Workpiece 5 Second Upset Workpiece 9 Middle Push Section 11 Ring-shaped Workpiece 17 Third Upset Workpiece

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomio Inukai 1345-8 Shibukawa City, Gunma Prefecture (72) Inventor Koichi Sakaguchi 1-4-6 Tsukiwa, Otsu City, Shiga Prefecture Omi Forging Co., Ltd. (72) Inventor Shigeru Okitsu 1-4-6 Tsukiwa, Otsu-shi, Shiga Omi Forging Co., Ltd. (72) Inventor Yoshinori Hongo 1-4-6 Tsukiwa, Otsu-shi, Shiga Ouchi Forging (72) Inventor Hiroyuki Sawai Kanagawa 133-96 Tehiro, Kamakura-shi (72) Takashi Yoshikai 2-3-22 Nakatehara, Kohoku Ward, Yokohama City, Kanagawa Prefecture

Claims (1)

[Claims] 1. A upset work piece is prepared by heating a cylindrical steel billet having a first predetermined height H in which a large number of metal flows are formed in the axial direction of the cross section in a hot forging zone and then performing upsetting. Manufacturing, and then inverting the first upset and then upsetting the first upset to produce an upset having a second predetermined height H2, after which The center portion of the plane of the second upsetting workpiece is evenly pressed from above and below to form the intermediate pressing portion, and then the intermediate pressing portion is hollowed out to form a ring-shaped workpiece, and then the ring. After the rolling work is performed on the work piece, a width upsetting is performed to form a third upset work piece having a third predetermined height H3, and the first predetermined height of the cylindrical steel billet. The upset ratio, which is the ratio of the height reduction amount (H-H3) of the cylindrical steel billet to the height H, is set to 0.50 to 0.65. Production method of the outer ring for ball bearings, characterized by.