JP2003181590A - Ball-shaped product and method and apparatus for manufacturing it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ball-shaped product capable of easily using for a horizontal high-speed forging machine, for example, and secure a uniform work margin in a polishing process after forging, and to provide a method and an apparatus for manufacturing the ball-shaped product. <P>SOLUTION: The ball-shaped product 1 is made of bearing steel and comprises an almost globular main body 2 and a ring part 4 which is projected in the shape of a tangent along the longest circumference line of the main body 2 (for example, the equator of the earth). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention has a diameter of, for example, 1
The present invention relates to a ball-shaped product for obtaining a 0 mm ball bearing and the like, a manufacturing method thereof, and a manufacturing apparatus thereof.

[0002]

2. Description of the Related Art In order to form a ball product having a diameter of several tens of millimeters by hot forging, as shown in FIG.
A forging device 40 consisting of a die 44 was used. The punch 41 has a substantially hemispherical cavity 42 at its tip and a thin peripheral edge 43 thereof. Also, die 4
4 has a substantially hemispherical cavity 45 at one end surface.
In advance, a cylindrical blank (not shown) obtained by cutting a steel bar heated to a predetermined temperature is upset and forged, so that the whole having a flat end surface 47, 48 and a peripheral surface protruding in a curved shape is almost barrel-shaped. The intermediate material 46 of is prepared.

Next, as shown in FIG. 4A, the intermediate material 46 heated to a required temperature is placed in the cavity 4 of the die 44.
5 and the punch 41 is moved toward the die 44. As a result, as shown in FIG. 4 (B), a ball product 49 having a substantially spherical outer shape can be formed by hot forging. However, in the forging device 40, since the cross section of the peripheral edge 43 of the punch 41 has a thin sharp edge, the vicinity of the peripheral edge 43 is likely to be broken or chipped, which is not practical.

In order to solve the above problems, a forging device 5 comprising a punch 51 and a die 54 as shown in FIG. 4 (C).
A method of hot forging a ball using 0 is also performed.
The punch 51 of the forging device 50 has a thick peripheral edge 53 around a cavity 52 located at the tip thereof, while the die 54 has a cavity 56 facing the cavity 52 and a step 58 around the cavity 56. And a ring-shaped guide 55. After inserting the barrel-shaped intermediate material 46 into the cavity 56 of the die 54 in advance, as shown in FIG. 4 (C), the punch 51 is brought closer and the peripheral edge 53 is inside the guide 55 of the die 54. And it is made to enter just before the step 58. At this time, in the narrow gap between the peripheral edge 53 of the punch 51 and the step 58 of the die 54, a part of the material 46 enters and a relatively thin disk-shaped burr 64 is formed.

The ball-shaped product 60 hot forged by the forging device 50 is along the longest circumferential line (corresponding to the equator of the earth) in the spherical ball body 62, as shown in FIG. 4 (D). , Has a disc-shaped burr 64 that projects in the radial direction. The width and thickness of the burr 64 may vary depending on individual forging steps. For this reason, when the ball-shaped product 60 is shaped into a true sphere by polishing or the like in the next step, the machining allowance to be polished becomes uneven, which affects the quality of the obtained ball bearing and the like. . Further, in the above ball-shaped product 60, since the disc-shaped burr 64 is projected, even if the punch 51 is separated after forging, it is difficult to take out because it closely adheres to the die 54 and is difficult to grip with a jig. There was also a problem that it was not suitable for machines.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the problems in the conventional techniques described above, and the machining allowance of the polishing step after forging is uniform, and can be easily applied to, for example, a horizontal high-speed forging machine. An object of the present invention is to provide a ball-shaped product, a manufacturing method thereof, and a manufacturing apparatus thereof.

[0007]

In order to solve the above-mentioned problems, the present invention has been conceived to have a thin and common shape for burrs protruding to the outside of a ball-shaped product. That is, the ball-shaped product of the present invention (Claim 1) is made of steel or the like, and includes a main body having a substantially spherical shape as a whole, and a ring portion protruding tangentially along the longest circumferential line of the main body. , Is characterized.

According to this, the ring portion projecting tangentially to the substantially spherical main body has a flat columnar outer shape. Therefore, the shape and thickness of the ring portion are likely to be uniform, and the machining allowance in the polishing in the next step can be uniformized, so that the quality of the ball bearing or the like of the final product can be stabilized. Further, since the ring portion facilitates gripping with a jig, it can be easily applied to, for example, a horizontal high-speed forging machine. In this specification, the longest circumference line is
It refers to the longest circumferential line on the surface of the spherical body, and corresponds to, for example, the equator when the body is regarded as the earth. Further, the "tangential shape" refers to a tangent line of the main body peripheral surface orthogonal to the longest circumferential line.

Further, the method for producing a ball-shaped product of the present invention
(Claim 2) comprises a first forming step for forming a substantially barrel-shaped intermediate material by upsetting a cylindrical material made of steel or the like in the axial direction thereof and forging the intermediate material. , A punch having a substantially hemispherical cavity at the tip,
A die having substantially the same cavities facing each other and extending from the periphery of the cavity and including an annular surface that receives the outer peripheral surface of the punch halfway, and then inserting the punch into the cavity of the die. A second forming step of forming a ball-shaped product including a substantially spherical main body and a ring portion projecting tangentially along the longest circumferential line of the main body by forging closer to each other. Characterize. In the second molding step, the tip surface of the punch stops at a position (bottom dead center) at a predetermined distance from the step of the die.

According to this, in the second forming step, the punch approaches the cavity of the die and enters part way along the annular surface of the die, so that the intermediate material is the tip of the punch, the annular surface of the die, and Overhang in the space surrounded by the steps of the die. As a result, the ball-shaped product including the ring portion can be surely forged. Further, since the ring portion facilitates gripping with, for example, a sandwich jig, it is possible to perform sequential high-speed forging in which a large number of materials are sequentially formed into ball-shaped products by sequentially moving between the above steps. Becomes Further, even if the punch is separated from the die after the second molding step, the obtained ball-shaped product is not taken out carelessly from the die, so that it can be reliably taken out. Therefore, the productivity of the ball-shaped product forging process can be improved.

Further, the ball-shaped product manufacturing apparatus of the present invention
(Claim 3) has a cavity having a substantially cylindrical outer shape and a substantially hemispherical shape provided at the distal end of the cavity, and a punch having a distal end surface surrounding the cavity with a predetermined thickness, and a cavity facing the cavity. And a cavity having a substantially hemispherical shape and recessed toward the base end, and a die having an annular surface extending through a step around the cavity and partially receiving the punch. According to this, the second forming step of forging the ball-shaped product including the ring portion from the intermediate material can be reliably performed without damaging the vicinity of the front end surface of the punch.

Further, according to the present invention, the punch has a holder having a tip end surface forming a part of the cavity at an axial center thereof and movable along the axial direction of the punch.
Alternatively, the die includes an apparatus for manufacturing a ball-shaped product (claim 4), which has an ejector that is capable of projecting and retracting along the axial direction of the die near the center of the cavity. According to this, the substantially barrel-shaped intermediate material inserted into the die is held while being held concentrically with the axis of the punch, and the second molding step is performed reliably, and the ball-shaped intermediate material obtained after this step is obtained. By gripping the product with a jig, it can be reliably taken out from the die. Therefore, the second molding step can be executed more reliably. The holder and the ejector (knockout pin) may be combined in the same manufacturing apparatus.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments for carrying out the present invention will be described with reference to the drawings. FIG. 1 (A) is a perspective view showing a ball-shaped product 1 of the present invention, and FIG. 1 (B) is a sectional view thereof. The ball-shaped product 1 is made of, for example, bearing steel (SUJ2), and has a substantially spherical body 2 as shown in FIGS.
And a ring portion 4 projecting tangentially along the longest circumferential line (equivalent to, for example, the equator of the earth) on the surface of the main body 2 and orthogonal thereto. Also, the top of the main body 2
A flat surface 6 having a circular shape in plan view is located (corresponding to the North Pole of the earth), and a thin curve is projected from the main body 2 at the bottom of the main body 2 (corresponding to the South Pole of the earth) and a bottom view is provided. The circular curved surface portion 8 and its edge line 9 are located.

As shown in FIGS. 1 (A) and 1 (B), the ring portion 4 has a straight line portion having a constant width which is tangential along the surface of the main body 2 in a side view, and surrounds the whole circumference of the main body 2. Along with, but slightly projecting in the radial direction. By the way, the main body 2
When the diameter of the ring is about 59 mm, the diameter of the ring part 4 is about 60
mm and its width is 16 mm. The flat surface 6 has a diameter of about 10 mm, and the curved surface portion 8 has a diameter of about 20 mm. The flat surface 6 can be formed by a punch holder in the manufacturing apparatus described later, and the curved surface portion 8 can be formed in the vicinity of the ejector of the die in the manufacturing apparatus described later. Not an essential element. Further, the alternate long and short dash line in FIG. 1 (B) indicates a machining allowance which is polished and removed in the next polishing step. That is, the ball-shaped product 1 is an intermediate product for manufacturing, for example, a ball bearing or the like.

According to the ball-shaped product 1 as described above, the ring portion 4 which is tangential to the main body 2 and protrudes thinly has a flat columnar outer shape. Therefore, the ring portion 4 has a shape and a thickness. Since it is likely to be uniform and the machining allowance in the polishing of the next step can be made uniform, it is possible to stabilize the quality of the final product such as the ball bearing. Further, since the ring portion 4 makes it easy to grip with a jig immediately after the second molding step described later, it can be easily applied to, for example, a horizontal high-speed forging machine.

Next, a method of manufacturing the ball-shaped product 1 of the present invention and a manufacturing apparatus 20 used for the method will be described with reference to FIGS. FIG. 2A shows a cylindrical raw material (blank) 10 obtained by cutting a steel bar made of the bearing steel and heated to a required temperature (about 1100 to 1200 ° C.). As shown in FIG. 2 (A), the material 10 has a pair of end faces 12 and 14 facing each other, and has a diameter of about 46 mm and a length of about 69 mm. Such a cylindrical material 10
On the other hand, upsetting forging (first forming step: free forging) is performed between a pair of tools whose tip surface (not shown) is flat along the axial direction. As a result, as shown in FIG.
Intermediate material 1 in which 8 is curved and protrudes and the whole is almost barrel-shaped
It becomes 6. The maximum diameter of the intermediate material 16 is about 54 mm.
And the length is about 56 mm.

Next, the intermediate material 16 is subjected to a second molding step. In the second molding step, a ball-shaped product manufacturing apparatus 20 of the present invention as shown in FIG. 2 (C) is used. In addition, the intermediate material 16 is a jig 1
In a state where 8 is gripped, it is carried into the manufacturing apparatus 20 from near the pair of tools in the first molding step. Manufacturing equipment 2
As shown in FIG. 2 (C), 0 is a hot work tool steel (for example, Fe
-3 wt% Cr-3 wt% Mo; JIS: SKD7 equivalent).

As shown in FIG. 2 (C), the punch 21 has a cavity 22 having a substantially cylindrical outer shape, a substantially hemispherical shape at the tip (lower end in the drawing), and a cavity 22 recessed toward the base end. Around the cavity 22, a tip surface 23 having a predetermined width dimension (thickness) is located, and the center of the bottom of the cavity 22 (the axial center of the punch 21) moves along the axial direction of the punch 21. A possible holder 24 penetrates. The holder 24 integrally has an intermediate large-diameter portion 26 and a base end portion 28 having a diameter slightly smaller than the intermediate-diameter portion 26, and has a small-diameter hole 25 and a large-diameter hole 25 formed in the center of the punch 21 along the axial direction. It is inserted in the diameter hole 27.
Further, the holder 24 is wound around the base end portion 28 of the cavity 24 due to the elasticity of the coil spring 29 arranged between the large diameter portion 26 and the base end portion of the punch 21 (not shown).
It is constantly pressed downward in FIG. 2 (C) so that it can be projected to the vicinity of the center in 2.

On the other hand, as shown in FIG. 2C, the die 30 includes a substantially columnar main body 31 and a ring-shaped annular piece 35 fixed to a front end surface 34 thereof with bolts (not shown) or the like. The main body 31 has a cavity 32 facing the cavity 22 of the punch 21 and having a substantially hemispherical shape and recessed toward the base end of the main body 31. Further, the annular piece 35 has an annular surface 36, which extends along the axial direction of the cavity 32 inside, through the circular step portion 33 located in the periphery of the cavity 32 in plan view. Furthermore, the main body 3
In the vicinity of the center of the cavity 32 in FIG. 1, a through hole 37 that penetrates the main body 31 along the axial direction thereof is bored, and an ejector (knockout pin) 38 is movable in the through hole 37 and the cavity 32 It is arranged so that it can be projected and retracted (projected and immersed) from the bottom of the. The tip surface of the ejector 38 is a curved surface continuous with the cavity 32.

As shown in FIG. 2 (C), the intermediate material 16 maintaining the heating temperature has its peripheral surface 18 held by a jig (not shown), and the annular piece 35 and the cavity 32 of the die 30. Inserted inside. Next, as shown in FIG. 2 (D), the punch 21 approaches the die 30, and the tip end surface of the holder 24, which approaches the punch 21, contacts the one end surface 12 of the intermediate material 16. As a result, the intermediate material 16
Is sandwiched between the holder 24 and the center of the bottom surface of the cavity 32 of the die 30, and the axis of the intermediate material 16 is determined by the punch 21 and the cavities 22, 3 of the die 30.
Positioned coaxially with 2. At this time, the holder 24
Moves to the base end side of the punch 21 while compressing the coil spring 29.

Further, as shown in FIG.
When the tool is moved closer to the die 30, the vicinity of the end surfaces 12 and 14 of the intermediate material 16 makes surface contact with the cavities 22 and 32 of the punch 21 and the die 30 and plastically deforms following these shapes. That is, as shown in FIG. 3A, the intermediate material 16 fills the insides of the cavities 22 and 32,
Plastic deformation occurs near the both ends. As a result,
The intermediate material 16 has a substantially elliptical cross-sectional shape as shown. Meanwhile, the tip surface of the holder 24 is
Since it is pushed by the expansion deformation of the cavity 22, it moves to the vicinity of the bottom of the cavity 22.

As shown in FIG. 3 (B), subsequently, the punch 21 is brought closer to the die 30 side, and the tip surfaces 2 of the both are approached.
3 and the step portion 33 are brought close to each other. At this time, the front end surface 23 of the punch 21 penetrates along the inside of the annular surface 36 of the annular piece 35 to the middle of the annular surface 36. As a result, the die 21 comes close to the die 30 to the position of the bottom dead center, and as shown in FIG. 3B, the oval intermediate material 16 causes pressure on the entire surfaces of the cavities 22 and 32. While being pressed. As a result, it is plastically deformed into the substantially spherical main body 2 following the shapes of the cavities 22 and 32, and at the same time, it is surrounded by the tip end surface 23 of the punch 21, the step portion 33 of the die 30, and the annular surface 36 of the annular piece 35. Even in the space of rectangular cross section and circular shape,
The material 16 is projected. During this time, the punch 21
Since the front end surface 23 has a predetermined thickness, damage such as chipping does not occur in the vicinity thereof.

As a result of the above, as shown in FIG. 3 (B), the ring portion 4 which is thinly projected over the entire circumference of the substantially spherical main body 2.
Is formed. As a result, the main body 2 has a substantially spherical shape.
The ball-shaped product 1 including the ring portion 4 protruding tangentially along the longest circumferential line thereof is formed by hot forging (second forming step). Since the ring portion 4 is thin and the outer diameter is always the same, the step portion 3 of the die 30 is formed.
Do not stick to 3.

At the end of the second molding step, the holder 24
Has moved to a position where its tip surface is substantially flush with the bottom surface of the cavity 22 and is in surface contact with the material 16, so that the flat surface 6 is formed on the ball-shaped product 1. Further, in the second molding step, the tip surface of the ejector 38 of the die 30 is pushed toward the base end of the main body 31 by the material 16. Therefore, the curved surface portion 8 may be formed on the opposite side of the flat surface 6 along the ejector 38 and a part of the through hole 37.

Then, as shown in FIG. 3C, the punch 2
1 is separated from the die 30, and the ejector 38 is projected from the bottom surface of the cavity 32 of the die 30. As a result, the ball-shaped product 1 is separated from the cavity 32 of the die 30, and the ring portion 4 thereof is guided along the axial direction of the annular surface 36 inside the annular piece 35. This allows
The ball-shaped product 1 does not accidentally fall out of the die 30. Further, by ejecting the ejector 38 from the bottom surface of the cavity 32 and grasping the ring portion 4 exposed from the annular piece 35 with a jig (not shown), the ball-shaped product 1 can be reliably taken out of the manufacturing apparatus 20.

On the other hand, in the punch 21 separated from the die 30, the holder 24 is subjected to elasticity by the coil spring 29 as shown in FIG.
Move into 2 and project. As a result, the following intermediate material 16
It is possible to further perform the above-mentioned second forming step of hot forging. The obtained ball-shaped product 1 is shaped into a predetermined spherical shape by polishing and removing the machining allowance of the surface layer in the next polishing step, and is subjected to a required heat treatment or the like to obtain a ball bearing or the like. It becomes a spherical product (final product).

Further, the first molding step shown in FIGS. 2A and 2B and the second molding step using the manufacturing apparatus 20 shown in FIGS. 2C to 3C are By arranging the pair of forging tools used in one molding step and the manufacturing apparatus 20 adjacently, the ball-shaped products 1 are sequentially obtained from the raw material 10 through the intermediate raw material 16 in a progressive manner. For example, horizontal type high speed forging can be performed.

The present invention is not limited to the form described above. For example, the ball-shaped product of the present invention includes a form in which the main body has an elliptical cross section and the ring portion 4 is projected along the outer peripheral surface orthogonal to the long axis thereof. Alternatively, a form having a through hole or a recess having a required diameter in a body having a substantially circular or elliptical cross section along a direction orthogonal to the plane including the ring portion 4 is also included. Further, the material of the ball-shaped product is not limited to the bearing steel, but includes other steel types, titanium, aluminum, and alloys based on these. Further, the preheated raw material 10 may be reheated to the required temperature at the stage of the intermediate raw material 16, for example, without being directly subjected to the first and second molding steps. In addition, the die 30
The body 31 and the annular piece 35 may be integrally molded.

[0029]

The ball-shaped product of the present invention described above
According to the first aspect, the ring portion protruding tangentially to the substantially spherical main body has a flat columnar outer shape, so that the shape and thickness of the ring portion are likely to be uniform. As a result, the machining allowance in the polishing in the next step can be made uniform, so that the quality of the final product such as the ball bearing can be stabilized. Moreover, since the ring portion facilitates gripping with a jig, it can be easily applied to a horizontal high-speed forging machine, for example.

Further, the method for producing the ball-shaped product of the present invention
According to (Claim 2), the ball-shaped product including the ring portion can be surely forged, and the ring portion facilitates gripping with a jig. Therefore, a large number of materials can be sequentially moved by sequentially moving between the steps. It becomes easy to perform high-speed forging such as a horizontal die for forming a ball-shaped product. Moreover, even if the punch is separated from the die after the second molding step, the obtained ball-shaped product is not inadvertently extracted from the die, so that it can be reliably taken out by a jig or the like. Therefore, the productivity of ball-shaped products can be improved.

Furthermore, the ball-shaped product manufacturing apparatus of the present invention
According to the third aspect, the second forming step of forging the ball-shaped product including the ring portion from the intermediate material can be reliably executed without damaging the vicinity of the front end surface of the punch. In addition, according to the ball-shaped product manufacturing apparatus of claim 4, the intermediate material inserted in the die is held concentrically with the axis of the punch and the second molding step is performed reliably.
The ball-shaped product obtained after such a step can be gripped by a jig or the like and reliably taken out from the die. Therefore, the second molding step can be executed more reliably.

[Brief description of drawings]

FIG. 1A is a perspective view showing a ball-shaped product of the present invention,
(B) is sectional drawing in the viewing angle along the BB line in (A).

2A and 2B are schematic views showing a first molding step of the manufacturing method of the present invention, and FIGS. 2C and 2D show a part of the manufacturing apparatus and the second molding step of the present invention. Schematic.

3A to 3C are schematic views showing a second molding step following FIG. 2D.

4A to 4D are schematic views showing a conventional manufacturing method or a ball-shaped product obtained.

[Explanation of symbols]

1 ……………… Ball-shaped product, 2 ………………
Main body, 4 …………………… Ring part, 10…
……… Material, 16 ………… Intermediate material,
20 ………… Manufacturing equipment, 21 ………… Punch,
22, 32 ... Cavity, 23 ......... Tip surface, 24 ......... Holder, 30 ...
…… Die, 33 ………… Step, 3
6 ………… ring surface, 38 ………… ejector

Claims (4)

[Claims] 1. A ball-shaped product comprising a main body made of steel or the like and having a substantially spherical shape, and a ring portion protruding tangentially along the longest circumferential line of the main body. 2. A first forming step of forming a substantially barrel-shaped intermediate material by upsetting a cylindrical material made of steel or the like in its axial direction and forging the intermediate material at the tip. Between a punch having a substantially hemispherical cavity and a die having a substantially similar cavity facing each other and having an annular surface extending from the periphery of the cavity and partially receiving the outer peripheral surface of the punch. After being inserted, the punch is brought closer to the cavity of the die to forge a ball-shaped product including a substantially spherical body and a ring portion projecting tangentially along the longest circumferential line of the body. A second molding step, and a method for manufacturing a ball-shaped product, comprising: 3. A punch having a substantially cylindrical outer shape, a substantially hemispherical shape provided at the tip thereof, which is recessed toward the base end, and a tip surface surrounding the periphery thereof with a predetermined thickness, and a punch facing the cavity and substantially Manufacturing a ball-shaped product, comprising: a hemispherical cavity that is concave toward the proximal end; and a die that extends through a step around the cavity and has an annular surface that partially receives the punch. apparatus. 4. The punch has a holder whose tip end surface forms a part of the cavity at the axial center thereof and is movable along the axial direction of the punch. The ball-shaped product manufacturing apparatus according to claim 3, further comprising an ejector that can be retracted along the axial direction of the die near the center of the cavity.