JP2963607B2 - How to make inner and outer rings of bearings - Google Patents

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 and an inner ring of a bearing.

[0002]

2. Description of the Related Art FIG. 1 shows a process chart of the most advanced method of manufacturing a small-diameter bearing at present. In the manufacturing method shown in this figure, an outer ring and an inner ring are manufactured in the following steps. (1) A bar material 1 as a raw material of a bearing is forged by a forging machine 2 to form a disk having a hole at the center. Then, it is annealed by heat treatment. The raw material 3 that has been subjected to this processing is transported to a processing factory. (2) The disk-shaped raw material 3 transported to the processing factory is polished to a width that forms the side surfaces of the outer ring portion and the inner ring portion. In this step, the width of the raw material 3 is processed to be equal to the width of the completed outer ring 5 and the inner ring 6. (3) The outer diameter surface of the raw material 3 is polished. In this step, the outer diameter of the raw material 3 is processed to be equal to the outer diameter of the completed outer ring 5. (4) Turning the inner surface of the raw material 3. In this step, the inner diameter of the raw material 3 is turned equal to the inner diameter of the completed inner ring 6.
By the way, in this specification, "turning" is used in a broad sense including polishing. (5) Turning the outer peripheral corner and the inner peripheral corner into a round surface. (6) The groove 4 is turned on one surface of the raw material 3 to separate the outer ring and the inner ring. The width of the groove 4 is determined so that the inner diameter of the outer ring separated by the groove 4 and the outer diameter of the inner ring are substantially the dimensions of the finished product. (7) The raw material 3 is reversed, and the groove 4 is also turned on the opposite surface. (8) Stop the outer ring and press the inner ring to separate the outer ring and the inner ring. (9) Turning the outer track 7 on the inner surface of the outer ring. (10) Turning both sides of the outer groove 9 for fitting the seal of the bearing on the outer ring. (11) The inner track 8 is turned on the outer peripheral surface of the separated inner ring. (12) The outer peripheral surface of the inner ring is turned to complete the inner ring.

The outer ring 5 and the inner ring 6 manufactured by the above process
Is a bearing race with a machining accuracy of ± 4/100 mm. The bearing race processed to this precision is conveyed to a bearing assembly factory, quenched and polished, and finished to the order of 1/1000 mm, and assembled as a bearing. In the present specification, the finished product of the outer race 5 and the inner race 6 means a state before being transported to a bearing factory, that is, a state of a bearing race before being polished and processed to a predetermined accuracy.

[0004]

The method for manufacturing the outer ring and the inner ring as described above cannot effectively use raw materials. Further, there is a disadvantage that a large amount of chips is generated in the manufacturing process. This is because the groove 4 is turned on the disk-shaped raw material 3 in order to separate the outer ring 5 and the inner ring 6. Bearings are basic components often used in many mechanical devices. For this reason, it is extremely important to mass-produce at low cost. The above-mentioned processing method conventionally performed is
Each processing step has already been considered to the utmost and production costs have been reduced to a minimum. Therefore, it is almost impossible to further reduce the manufacturing cost by the conventional method.

In order to mass-produce the outer ring and the inner ring at low cost, it is necessary to reduce raw material costs and the cost required for processing. The present inventors first paid attention to cutting and removing a considerable amount of metal in a step of turning a groove to separate it into an outer ring and an inner ring. The turning process reduces the yield of the raw material because a part of the raw material is cut off. In addition, large amounts of chips that are expensive to dispose of are generated.
If the turning process that generates chips can be omitted and the outer ring and inner ring can be separated, the use efficiency of raw materials can be improved and the yield can be improved, and the amount of chips that require time to dispose can be significantly reduced. . Therefore, there is an effect that the raw material cost can be reduced and the overall processing cost can be reduced.

[0006] The outer ring and the inner ring should not be scrapped.
The method of separation by the method described in Japanese Patent Application Laid-Open No. 52-119463 is disclosed.
Information. The manufacture of the bearings described in this publication
In the manufacturing method, an inner ring and an outer ring are manufactured in the steps shown in FIG. (1) The raw material 21 is processed into a flat shape. (2) Forming a flat material into a bottomed shape with a concave portion
You. The material processed into this shape has an inner ring at the bottom,
The tubular part becomes the outer ring. The outer diameter and inner diameter of the cylinder are the same as the outer diameter of the outer ring.
It is processed equal to the inside diameter. In addition, the overall height of the material is outside
It is machined to the same height as the wheel. (3) The axis of the inner part of the cylindrical part of the material processed into a bottomed shape
Cut along the cutting line extending in the direction
A ring is formed to separate the inner ring. Furthermore, in this process, the bottom
Ring element for manufacturing the inner ring by punching the center from the part into a circle
The material 22 is formed. When forming the annular material 22,
The cut circular part is discarded as scrap. (4) The annular material 22 has an outer diameter larger than the inner ring and an inner ring.
The inner diameter is smaller than the inner diameter. In addition, the annular material
It is thinner than the inner ring. Place a thin annular material outside the specified
The inner ring 23 having a diameter, an inner diameter, and a thickness is processed.

[0007] The production method described in this gazette
The outer ring and inner ring can be separated to prevent scrap from
There are features. However, this manufacturing method is
To eliminate any scraps that can be made when separating the inner ring
In order to manufacture the inner ring from an annular material processed into a thin plate,
Need to be In other words, the inner ring is made from a thin annular material
Need to be processed. Outer diameter of annular material processed into inner ring
Is equal to the inner diameter of the outer ring, and the outer and inner rings are separated.
This is because there is no scrap that can be made. Thin ring
It is extremely difficult to process the shaped material into the inner ring. Especially
The bearing is made of a hard metal material with a high carbon content
The annular material pressed into a thin plate
I will make it thicker in the later processing and make the outer diameter smaller and make the whole thicker
Is extremely difficult in practice. Furthermore, for bearings
Extremely high reliability is required.
It is extremely difficult to machine thick and small outer diameters.
You. It is made by processing a thin annular material thicker to reduce the outer diameter.
Is a difficult process, the inner race, which is the rolling surface of the steel ball,
Can not eliminate the possibility of cracks etc. on the outer peripheral surface
Because. In the bearing manufacturing process,
Even if one defective product occurs every 10,000
Must be reliably removed and its sorting is extremely difficult
It is.

[0008] Instead of using a thin annular material for the inner ring,
Separate into a shape almost equal to the completed inner ring and outer ring
A method is also described. This manufacturing method is as shown in FIG.
In addition, the raw material 21 was processed to be equal to the thickness of the outer ring and the inner ring.
Then, punch the center with a size equal to the inner diameter of the inner ring, and then
In addition, the outer ring and the inner ring are machined into steps
The outer ring and the inner ring are separated by removing the space between the inner rings in a disk shape. This
The outer ring and inner ring separated by the method of thickening thin metal material
No need to process. However, this method uses the outer ring and inner ring
You can eliminate the disc-shaped scraps that can be made in between
Absent. For this reason, raw materials cannot be used effectively.

That is, in the conventional method, the outer ring and the inner ring are separated.
Or you can scrap when away, or, scrub
If it is not possible to machine the inner ring,
Is that high-quality inner rings cannot be mass-produced inexpensively.
is there.

A first object of the present invention is to solve this problem.
And punching the inner ring from the outer ring
In addition, by rolling this,
Bearing inner ring that can improve the efficiency and reduce raw material costs
And a method of manufacturing the outer ring.

By the way, the inner ring separated by punching
The outer diameter is equal to the inner diameter of the separated outer race. Conventional
Turning a groove of a predetermined width between the outer ring and the inner ring as in the manufacturing method
Therefore, the outer ring and the inner ring are not separated. This way
The inner ring separated by
It is extremely difficult. First, a center hole is drilled in the raw material, and this is punched and separated into an inner ring and an outer ring. When the inner ring and the outer ring are separated, a crack 12 is generated in the inner ring 6 and the center hole 11 is formed. Is deformed. 2 and 3 show a state of the inner ring 6 which has been provided with the center hole 11 and punched from the outer ring. As shown in FIG. 2, the inner ring 6 separated from the outer ring by punching has a crack 12 on the opposite surface (right side in FIG. 2) punched with a punch. As shown in FIG. 3, cracks 12 are radially generated from the center hole 11 in the punched inner race. Further, in the punched inner race, the center hole 11 is deformed into a tapered shape as shown in FIG. For example, when the raw material 3 having a center hole 11 having an inner diameter of 11.5 mm is punched and separated into an outer ring and an inner ring, the center hole 11 is formed.
As shown in FIG. 2, one end is 9.78 mm and the other end is 1
It has a tapered shape of 2.30 mm.

As described above, the crack 12 is generated in the inner ring and the center hole 11 is deformed when the raw material 3 is punched and separated into the outer ring and the inner ring, as indicated by arrows in FIG. This is because a stress acts internally in the direction. That is, the raw material 3 pressed by the punch 14 is subjected to a stress directed toward the inner diameter in the vicinity of the pressing surface 14A. On the opposite side, a stress acts to escape to the outer diameter side. That is, strong compressive stress acts near the pressing surface 14A, and tensile stress acts on the opposite side. The compression stress of the pressing surface 14A is the center hole 1
1 is deformed small, and the tensile stress on the opposite side enlarges the central hole 11. In addition, strong tensile stress can cause cracks 12
Cause

In order to solve this drawback, the present inventors have experimented with a method of inserting a bush (not shown) into a previously drilled center hole to separate the outer ring from the inner ring. The bush inserted into the center hole of the raw material prevents the center hole from being deformed during punching. In particular, it is possible to effectively prevent the center hole from becoming small in the vicinity of the pressing surface. If the bush prevents the center hole from shrinking, the center hole on the opposite side can be less likely to become large. However, this method
As shown in FIG. 3, the inner ring that has been punched has many adverse effects that are easily broken in the radial direction . This is because the bush strongly presses and expands the inner surface of the center hole 11 during punching. In addition, in the method of punching the raw material 3 by inserting the bush, as shown in FIG. 2, it is also difficult to effectively prevent cracks generated on the side opposite to the pressing surface.

Further, when the inner race is separated from the outer race by punching a thick metal raw material, a step 6A is formed on the outer surface of the inner race as shown in FIG. The step 6A is finished by turning and removing this portion to form the inner ring 6 having a predetermined size. In order to reduce the turning amount, it is important to reduce the step 6A as much as possible. However, it is extremely difficult to reduce the step 6A of the inner ring when performing punching. This is because a considerably thick metal is stamped and separated into an outer ring and an inner ring.

The method of manufacturing the inner and outer rings of the bearing according to the present invention has been developed to further eliminate these drawbacks. An important second object of the present invention is to prevent cracking of the inner ring that occurs when performing punching, further prevent deformation of the center hole, separate the outer ring and the inner ring with a punching machine, It is an object of the present invention to provide a method for manufacturing an inner ring and an outer ring of a bearing capable of punching a center hole in the inner ring by punching. Another important object of the present invention is to reduce the step formed on the outside of the inner ring in the step of drilling a center hole in the punched inner ring, and to reduce the amount of turning after the inner ring and the outer ring of the bearing. It is to provide a manufacturing method.

[0016]

According to the manufacturing method of the present invention, an outer ring and an inner ring are manufactured as described below in order to achieve the above object. The manufacturing method of the present invention is based on
A metal raw material 3 formed in a disk shape having a small outer diameter is punched by a punching machine to separate it into an outer ring and an inner ring, and a center hole 11 is formed in the inner ring by a punching machine.

In the manufacturing method of the present invention, the raw material 3 is punched by a punching machine to separate it into an outer ring and an inner ring, and then the separated inner ring is further punched to form a center hole 11. That is, the raw material 3 having no center hole 11 is punched by a punching machine to separate the outer ring and the inner ring, and the inner ring separated from the outer ring is punched to form the center hole 11. Characterized in that the inner ring with the hole is roll-formed.

Further, in the method of manufacturing the inner ring and the outer ring of the bearing according to the present invention , the center hole is punched and formed in the inner ring separated from the outer ring by punching the raw material. Punching
The inner ring is preferably heat treated. This is because the residual stress generated in the inner ring by the punching process for separating the outer ring and the inner ring is reduced, and further, the hardness hardened by the punching process is reduced. In the heat treatment, the inner ring is heated to 600 to 900 ° C., preferably 700 to 850 ° C. or more to be cooled. Center hole
Both the inner ring with the bore and the outer ring separated from the inner ring.
Roll forming. Roll forming completes outer and inner diameter of inner ring
The outer diameter and the inner diameter of the inner ring, the finished outer ring outer diameter and inner diameter of the outer ring
Same shape for outer diameter and inner diameter.

[0019]

Method for producing inner and outer rings of the bearing of the working of the present invention, the inner ring that is separated from the outer ring, rolling molding by drilling a center hole 11 by processing punching. The inner and outer rings of the bearing are not manufactured by stamping a thin metal plate.
The thick disk-shaped raw material 3 is punched, separated into an outer ring and an inner ring, and then punched to form a center hole 11.
The manufacturing method of the outer ring and the inner ring of the present invention is as follows.
Separating the outer and inner rings, followed by drilling a central hole 11 in the port Nchingu machine the inner wheel to roll forming the inner and outer rings. this
The method does not turn the grooves, so no chips are generated. Groove
The conventional method of turning and separating is to separate the raw material into the outer ring and the inner ring.
Separate into rings and a significant amount of chips. The production method of the present invention
A process to separate raw materials into outer and inner rings by punching
Does not generate chips as much as possible. For this reason, raw materials are not wasted
By making effective use, it can be separated into an outer ring and an inner ring. Stamping
Outer ring and inner ring are races whose outer diameter and inner diameter are finished products.
Is not the size of The outer diameter of the inner ring after being punched
Is equal to the inner diameter of the outer ring. Outside and inside dimensions
Outer ring and inner ring with different methods are roll-formed and finished products
It is molded to the same size and race. Roll forming, turning
Instead of pressing the outer ring and inner ring to form
Does not occur. In addition, when molded by this method,
At the same time as forming the diameter to the specified size, the track was provided
Or round chamfering. For this reason,
Simple, easy and short time compared to turning method
Can be provided with tracks, etc.
You. Furthermore, the method according to the invention does not drill the center hole 11 first and then separate it into an outer ring and an inner ring as before. In the method of punching the raw material 3 in which the center hole 11 is perforated and separating it into an outer ring and an inner ring, the inner ring is damaged in the punching process in which the inner ring and the outer ring are separated. However, the method of the present invention punches the center hole 11 by punching the inner ring separated from the outer ring. Therefore, in the step of punching the raw material 3 and separating it into an outer ring and an inner ring, damage to the inner ring can be minimized. This is because the center hole 11 is not bored in the inner ring when separated from the outer ring. The inner ring separated from the outer ring is heat-treated to remove residual stress, and to further eliminate the work hardening of the punching process. The hardness of the heat-treated inner ring decreases, and the center hole 11 is punched by punching with a punching machine.

The inner ring punched in this state can not only prevent the occurrence of cracks 12 and the like when processing with a punching machine as in the prior art, but also form the center hole 11 by forming the outer shape neatly. There are features that can be done. As shown in FIG. 5, when the inner ring 6 fitted and set in the concave portion 18A of the die 18 to be punched is punched by a punching machine, the outer shape of the inner ring 6 is the same as that of the concave portion 18A of the die. This is because it is molded by being strongly pressed against the inner surface. For this reason, the manufacturing method of the present invention, when punching the center hole 11 in the inner ring,
The step 6A formed on the outside of the inner ring is reduced to form a beautiful shape. As shown in FIG. 5, the inner ring 6 having the large step 6A on the outside is fitted into the concave portion 18A of the mold 18 and the punch 19 is driven into the center. The spreading force acts. This expanding force strongly presses the outer diameter of the inner ring against the inner surface of the concave portion 18A of the mold 18 to reduce the step 6A. In particular, in the manufacturing method of the present invention, the inner ring softened by the heat treatment is inserted into the concave portion 18A of the mold 18 and punched, so that the inner ring that is easily deformed is expanded by the pressing force of the punch 19. Step 6
It is formed into a shape that reduces A. Therefore, the inner ring separated from the outer ring by the punching machine can prevent the occurrence of cracks in the step of heat-treating and punching the center hole 11, and form a clean surface by forming a small step on the outer surface,
Further, a center hole having a constant thickness is formed in the center.

[0021]

An embodiment of the present invention will be described below with reference to FIG. However, the following examples are intended to exemplify a method for embodying the technical idea of the present invention, and do not specify a method of manufacturing the inner ring and the outer ring of the bearing of the present invention in the following method. .

(1) Step of Cutting Bar Material to Predetermined Thickness As shown in FIG. 7, a cutter 10 is used to cut the cylindrical bar material 1 to a predetermined thickness to obtain a raw material 3 for a bearing.
And The bar material 1 is obtained by subjecting the structure to spheroidizing treatment.
Hardness is measured as HRB by Rockwell (B scale)
= 90 to 91 is used. This bar material 1
Contains the following components in addition to iron.

C: 0.95 to 1.10% by weight Si: 0.15 to 0.35% by weight Mn: 0.5% by weight or less P: 0.025% by weight or less S: 0.020% by weight % Cr or less 1.30-1.60% by weight Mo 0.08% by weight or less Ni 0.25% by weight Cu 0.25% by weight or less

However, SUJ3 to SUJ5 can be used for the bar material 1 instead of SUJ2. The bar material 1 has HR
B having a spheroidizing treatment in which B is in the range of 88 to 95 can be used. The cutter 10 for cutting the bar material 1 includes a rotating shaft 1
The circular saw blade 10B is fixed at a predetermined interval at 0A. The rotating shaft 10A of the cutter 10 is disposed in parallel with the bar material 1, and the rotating cutter 10 is moved closer to the bar material 1 to cut the bar material 1. The outer diameter of the bar material 1 is designed to be a size that can be formed into a predetermined size outer ring and inner ring by rolling and forming after punching. For example, a bar material 1 for producing a race in which the outer diameter of the completed outer race 5 is 40 mm has an outer diameter of 3 mm.
1 mm.

(2) Step of Punching Raw Material with Punching Machine to Separate Outer Ring and Inner Ring As shown in FIG. 8, raw material 3 is cut using a punching machine.
Is separated into an outer ring 5 and an inner ring 6. The punching machine is a mold 13 having a recess 13A into which the raw material 3 is fitted.
And a punch 14 for punching the center of the raw material 3. Further, the punching machine includes a punch guide 17 for inserting the raw material 3 into the recess 13A of the mold 13. With the punch guide 17 pressing the raw material 3, the raw material 3 is punched by the punch 14. Mold recess 13A
Is designed to have a slightly larger but substantially equal inner diameter than the outer diameter of the raw material 3 to prevent the outer diameter of the raw material 3 from being deformed during punching. The outer diameter of the punch 14 is substantially equal to the outer diameter of the inner ring 6 to be punched. In this punching machine, the raw material 3 is punched by a punch to separate the raw material 3 into an outer ring 5 and an inner ring 6. The outer diameter of the inner ring 6 to be stamped is, for example, the outer diameter of the inner ring 6 to be stamped is 22 mm in the case of manufacturing a race in which the outer diameter of the completed inner ring 6 is 25 mm.

(3) Step of heat-treating the inner ring separated from the outer ring The inner ring punched by a punching machine is heat-treated to eliminate work hardening and residual stress. The punched inner race is work-hardened when punched by the punch 14 with strong force. Also, strong residual stress is generated inside the inner ring. Heat treatment softens the inner ring. The heat treatment is performed by heating the inner ring to 800 ° C. for 10 minutes and then cooling it down.
If the temperature at which the inner ring is heated and heat-treated is too low, the inner ring cannot be sufficiently softened, and if it is too high, spheroidization of the material is hindered.
For this reason, the heating temperature of the inner ring is set in the range of 600 to 900 ° C. The heating time of the inner ring differs depending on the heating temperature. As for the heating time, preferably, the heating time at 750 ° C. or more is 10 minutes or more. If the heating time is too short, the inner ring cannot be sufficiently softened. If it is too long, there is no harm, but the running cost increases. Therefore, the heating time of the inner ring is set to an optimum value in consideration of the running cost and the degree to which the inner ring can be softened. The inner ring softened by the heat treatment is set in the punching machine again to prevent cracking when the center hole 11 is punched, and the outer surface is pushed out to the inner surface of the concave portion of the mold by the punch driven into the center. Can be molded.

(4) Step of punching center hole by punching the heat-treated inner ring The inner ring softened by the heat treatment is put into a concave portion 18A of a die 18 of a punching machine as shown in FIG. In a state where the cylindrical punch guide 20 presses the outer periphery of the inner ring 6, the inner ring 6 is punched by the punch 19 to punch the center hole 11. The mold 18 has a concave portion 1 in which the inner ring 6 can be fitted.
8A. The concave portion 18A has a columnar shape whose inner surface is a smooth surface. The inner diameter of the concave portion 18A is designed to be larger than the outer diameter of the inner ring 6 at a portion to be inserted into the concave portion 18A, but as small as possible so that the inner ring 6 stamped here can be inserted. For example, the inner diameter of the recess 18A is
It is designed to be 0.1 to 0.3 mm larger than the outer diameter of the portion that fits into A.

The inner ring separated from the outer ring by punching with a punching machine does not have the same outer diameter. As shown in FIG. 5, the inner ring has a smaller outer diameter at the center,
A step 6A is formed on the outer peripheral surface. The punching machine for forming the center hole 11 in the inner race 6 does not necessarily require the entire inner race 6 to be recessed 18.
Although it is not necessary to fit the inner ring A, the mold 18 shown in FIG.

By narrowing the gap between the recess 18A and the inner ring 6,
When punching with the punch 19, the outer peripheral surface of the inner ring 6 is
It is extruded strongly into the inner surface of 8A and formed into an ideal shape. This is because when the punch 19 punches the inner ring, a force acts to push the inner ring outward. The inner ring 6 whose outer peripheral surface is strongly pressed against the concave portion 18A is a mold 18
The recess 18A is formed so that the step 6A is reduced.

By the way, in an experiment actually conducted by the present inventors, when the inner ring was punched under the following conditions, the outer diameter was formed to be 28/1000 mm thicker at the point A having a step.
At point B, it was formed thicker by 5/1000 mm. Maximum outer diameter of inner ring (Dmax) 21.2 mm Thickness of inner ring (Lmax) 12.0 mm Inner diameter of mold recess ( Dm ) 21.4 mm Depth of mold recess ( Lm) )… 13.0mm Punch outside diameter (Dp)… 9.0mm Punch punching pressure… 60ton

(5) Step of heat-treating both the outer ring and the inner ring Raw materials having a hardness suitable for punching are separated into an outer ring and an inner ring by cold stamping, and then subjected to cold rolling and rolling. Cracks occur. In addition, when rolling is performed, it does not become completely circular due to distortion. This is because the stamped outer and inner rings are too hard. The stamped outer and inner rings are heat-treated to soften and remove work hardening and residual stress caused by the stamping. The outer ring and the inner ring work harden when punched with strong force.
Work hardening makes the outer ring and the inner ring separated by punching work harder than the hardness of the raw material.

Heat treatment is performed to soften the stamped outer and inner rings. Heat treatment for the outer ring and inner ring is 780
Heated to 780 ° C for 4 hours and 780 ° C to 700 ° C over 3 hours
Allow to cool slowly. When this heat treatment is performed, HRB before heat treatment is performed.
The HRB is 90 for the outer ring and the inner ring whose
To decline. HRB before punching and heat treatment is 11
The outer ring and the inner ring of 0 to 120 are punched from SUJ2 raw materials having an HRB of 90 to 91. That is, the raw material having an HRB of 90 to 91 becomes H
RB becomes 110-120, and when this is heat-treated, 90
To decline. However, HRB of heat treated outer and inner rings
Varies slightly depending on the measurement site.

The heat treatment in this step needs to soften the HRB of the outer ring and the inner ring to 94 or less. The bar material used for the bearing race is heated to 600 ± 25 ° C. and then gradually cooled, whereby the work hardening and the residual stress can be almost completely removed. The heat treatment in this step is not intended only to remove the residual stress and work hardening of the punching process. Heat treatment, in addition to removing residual stress, reduces the hardness of the outer ring and the inner ring to prevent cracking and deformation that occur during rolling. In consideration of this, the heat treatment after the punching process is performed by reducing the heating temperature of the outer ring and the inner ring by 7%.
The temperature is set to 00 ° C. or higher, more preferably 723 ° C. or higher. Heating to 723 ° C. or higher can reduce the hardness of the outer ring and the inner ring.

When the heating temperature is increased, the HR of the outer ring and the inner ring is increased.
B decreases. Further, even if the heating time is lengthened, the HRB decreases. However, when the heating temperature is too high, the spheroidization of the outer ring and the inner ring subjected to the spheroidization treatment is reduced. The heating temperature that does not impair the spheroidization of the inner ring of the outer ring is 900 ° C. or less. Therefore, in this heat treatment step, the outer ring and the inner ring are 700 to 9
Heated to 00 ° C, preferably 723-850 ° C. The heating time must be short when the temperature is high and long when the temperature is low. For example, when the heating temperature is 780 ° C., the heating time is 2 hours or more.

(6) Step of Turning Heat-Treated Outer Ring and Inner Ring The heat-treated outer and inner rings are heated to form a decarburized layer on the surface. The thickness of the decarburized layer is 5/100 to 8/100 mm. In order to remove this decarburized layer, the surfaces of the outer ring and the inner ring are turned. The outer ring and the inner ring are turned on the inner diameter and turned or polished on the outer diameter and the width. In order to completely remove the decarburized layer, the surface of the outer ring and the inner ring is turned by at least 100/100 mm.

(7) Step of Roll Forming Outer Ring and Inner Ring The outer ring and the inner ring whose surfaces are turned are roll-formed by cold rolling using a cold rolling forming machine. The inner ring that is cold-rolled can be heated to 50-100 ° C. The rolled outer ring and inner ring are finished to the dimensions of the completed outer ring and inner ring.

As shown in FIG. 9, the cold rolling forming machine has a mandrel 15 and a forming roll 16 inserted into the centers of the inner ring and the outer ring. The mandrel 15 is inserted into the inner diameter of the outer ring or the inner ring, and the forming roll 16 presses and rolls the outer periphery to cold-roll the outer ring and the inner ring. For example, if the inner diameter is 1
Mandrel 15 for rolling and forming the inner ring to 0.5 mm
Is the maximum outer diameter of the part that rolls the inner diameter of the inner ring is 10.3m
m, and the minimum outer diameter is about 8 mm. Outer ring and inner ring
Roll forming is performed to finish the A to H surfaces in FIG. That is, the A, B, C, and D surfaces of the outer ring and the E, F, G, and H surfaces of the inner ring
Finish the surface. The mandrel 15 that finishes the outer ring by rolling and forming into this shape has a ridge that forms an outer track on the outer ring. Forming roll 16 for rolling and forming the inner ring into this shape
Has a ridge that forms the inner track. As described above, when the inner race is formed by rolling and forming the inner race and the outer race is formed when the outer race is formed by rolling, there is a feature that the material of the portion removed as the race can be effectively used. However, it is needless to say that the inner track and the outer track can be processed by turning after rolling.

(8) Step of Turning to Finish Outer Ring and Inner Ring to Predetermined Dimensions The rolled outer ring is turned to width to finish it to predetermined dimensions, and also to turn grooves for fitting bearing seals. Formed. The inner ring is turned to a predetermined size by turning the width.

[0039]

The method of manufacturing a bearing according to the present invention provides an outer ring
Scraps do not occur when separating the inner ring
Nevertheless, a lot of outer and inner races with extremely high quality
There is a feature that can be produced. It is the bearing of the present invention
The manufacturing method is similar to the conventional method shown in FIG.
Because it is not necessary to manufacture the inner ring by processing
is there. The method of the present invention, when separating the outer ring and the inner ring,
Adjust the outer diameter of the inner ring to the
Equal to the diameter, but rolling both outer and inner rings separated
Since the outer diameter is increased by molding, the inner ring is made of a thin annular material.
No need to do. As shown in FIG. 11, the thickness in the axial direction
By comparison, an annular material whose width in the radial direction is
Conventional production by squeezing in the direction to form an inner ring with a predetermined outer diameter
It is extremely difficult to process a thin annular material into a thick inner ring.
Difficult to mass produce high quality bearings
Is almost impossible. The production method of the present invention
The inner diameter of the outer ring and the outer diameter of the inner ring
After that, since both the outer ring and the inner ring are roll-formed,
There is no need to machine the inner ring from a thin annular material. others
The outer ring and inner ring so that they cannot be scrapped.
Despite being able to produce high quality races inexpensively in large quantities
It is just ideal for bearing manufacturing method
Realizing the special features.

Further, according to the method of manufacturing the inner ring and the outer ring of the bearing of the present invention, the two steps of separating the outer ring and the inner ring and drilling a center hole in the inner ring can be efficiently performed by punching. The feature is that deformation and cracking of the processed inner ring can be minimized. In the manufacturing method of the present invention, the outer ring and the inner ring are separated by punching first, and then the inner ring is heat-treated to remove work hardening and residual stress, which is inserted into a concave portion of a mold and punched. This is because it is punched. The manufacturing method of the outer ring and the inner ring of the present invention is different from the conventional method of punching a raw material in which the center hole is punched in advance, and after separating the outer ring and the inner ring, the inner ring is punched to form the center hole. Perforate.
Further, the inner ring separated from the outer ring is softened by heat treatment, and then punched again to form a center hole. The inner ring, which is separated from the outer ring by this method and has a center hole, is efficiently processed in a very short time by two-step punching, and is difficult to solve by the conventional method. It has the feature that cracks and deformation at the time can be effectively eliminated. For this reason, the manufacturing method of the present invention has the feature that high quality outer and inner rings can be mass-produced at low cost.

Further, a notable feature of the present invention is that
An object of the present invention is to reduce the amount of turning of an inner ring having a center hole formed by punching. This is very important for the production of bearing races. The large amount of turning
This not only increases the turning cost, but also lowers the yield of raw materials, and furthermore, it takes time to dispose of chips.
The method of punching and separating the outer ring and the inner ring has a feature that the processing can be efficiently performed in a very short time, but a step is formed on the outer periphery of the punched inner ring as shown in FIG. This is because a considerably thick metal is stamped and separated into an outer ring and an inner ring. The inner ring having a step needs to be subsequently removed by turning the step. If the step is large,
The amount of turning of the inner ring increases. In the manufacturing method of the present invention, after the inner ring separated from the outer ring by punching is heat-treated and softened, the inner ring is fitted into a concave portion of a mold to punch a center hole.
The inner ring that is put in the recess of the mold and punched with a punch,
It is forcibly pushed outward by the inserted punch. This force is formed by strongly pressing the outer peripheral surface of the stepped inner ring against the concave portion of the mold. Accordingly, the inner ring having the center hole formed by punching is punched and the outer peripheral surface having a step is formed neatly by the concave portion. The outer peripheral surface of the formed inner ring has less steps. Therefore, the method of manufacturing the inner ring and the outer ring of the bearing of the present invention can separate the outer ring and the inner ring by two-step punching, further improve the machining efficiency by drilling a center hole, and reduce the turning amount of the inner ring. Features that can be reduced are also realized.

The method of the present invention, in which the outer peripheral surface of the inner ring is forged when drilling the center hole, has the effect of reducing the level difference and the amount of post-processing turning. There is also an effect on processing into a typical state. The outer peripheral surface of the inner ring becomes a rolling surface of the steel ball which is extremely important for the bearing. How ideal this surface can be has a significant effect on the life of the bearing. The inner ring can extend the life by keeping the outer peripheral surface in an ideal state. The inner ring can forge the martensite structure on the surface by forging the outer peripheral surface. The inner ring having a fine surface texture is prevented from peeling off when used and has a long life.

Further, in the method of manufacturing the inner ring and the outer ring according to the present invention, the inner ring having the center hole formed therein is roll-formed in a forged state. The inner ring to be roll-formed is further forged by pressing the outer peripheral surface with a forming roll. Therefore, the outer peripheral surface of the inner race is further finely textured in this step. As described above, the manufacturing method of the present invention, in which the outer peripheral surface of the inner race, which is the rolling surface of the steel ball, can have a dense structure, has an excellent feature that a long-life inner race can be manufactured.

[Brief description of the drawings]

FIG. 1 is a process diagram showing a manufacturing process of a conventional bearing.

FIG. 2 is a sectional view of an inner ring punched by a conventional method.

FIG. 3 is a perspective view of an inner ring punched by a conventional method.

FIG. 4 is a sectional view showing a state in which an inner ring is punched from an outer ring by a conventional method.

FIG. 5 is a sectional view showing a state in which a center hole is punched in an inner ring by the method of the present invention.

FIG. 6 is a process diagram showing a manufacturing process of the bearing according to one embodiment of the present invention.

FIG. 7 is a front view showing a state where the bar material is cut into a disk shape.

FIG. 8 is a cross-sectional view showing a state in which a raw material is stamped and separated into an outer ring and an inner ring.

FIG. 9 is a cross-sectional view showing a state where a stamped outer ring and an inner ring are roll-formed.

FIG. 10 is a cross-sectional view showing a cross section of an outer ring and an inner ring formed by rolling;

FIG. 11 Outer and inner rings to prevent scrap
Sectional view showing a conventional manufacturing method for separation

FIG. Conventional production of races by separating outer and inner rings
Sectional view showing the manufacturing method

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Bar material 2 ... Forging machine 3 ... Raw material 4 ... Groove 5 ... Outer ring 6 ... Inner ring 6A ... Step 7 ... Outer track 8 ... Inner track 9 ... Outer groove 10 ... Cutter 10A ... Rotating shaft 10
B ... Circular saw blade 11 ... Center hole 12 ... Crack 13 ... Mold 13A ... Recess 14 ... Punch 14A ... Pressing surface 15 ... Mandrel 16 ... Forming roll 17 ... Punch guide 18 ... Mold 18A ... Recess 19 ... Punch 20 ... Punch Guide 21 ... Raw material 22 ... Ring material 23 ... Inner ring

Claims (1)

(57) [Claims] We claim: 1. The metallic raw materials are formed into a disk shape of smaller outer diameter than the outer ring as a product and punching in Ponchingu machine, the outside diameter of the finished annulus is finished bearing
Separate inner ring with outer diameter smaller than outer ring and punch
Insert the inner ring separated from the outer ring into the concave part of the mold
The center hole is punched by punching with a punch of a punching machine, and both the inner ring with the center hole and the outer ring separated from the inner ring
The outer and inner diameters of the inner ring are
The outer diameter and inner diameter of the outer ring to the outer diameter of the completed outer ring.
Bearings characterized by being molded identically to the inner diameter
How to make wheels and outer rings.