JP4080182B2 - SHELL TYPE NEEDLE ROLLER BEARING AND MANUFACTURING METHOD THEREOF - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a raceway for a shell needle roller bearing and a method for manufacturing the same.
[0002]
The shell-shaped needle roller bearing is a needle roller bearing having a press-processed outer ring. This press-processed outer ring is also called a shell, and its inner peripheral surface becomes a raceway surface on which the roller rolls. Also called a bearing ring.
[0003]
[Prior art]
A shell-type needle roller bearing shown in FIG. 5 includes a race ring 1, a plurality of needle rollers 3 that are rotatably incorporated in a raceway surface, that is, an inner peripheral surface 2 of the race ring 1, and a needle roller 3. A retainer 4 that holds at equal intervals in the circumferential direction is a main component. The bearing ring 1 is manufactured by pressing from a steel plate blank. Inward flanges 1 a and 1 b bent at the inner diameter side are formed at both ends of the race 1.
[0004]
The manufacturing process of the conventional bearing ring 1 is shown in FIGS. 6 to 9 are cross-sectional views of the press device in each process, and FIG. 10 shows a cross-section of the material in each process.
[0005]
FIG. 6 shows the press apparatus in a state immediately before the start of processing. A flat blank, that is, a shell material 10 is set between the upper punch P1 and the lower punch P2 at the upper limit position. The punch guide G1 is elastically held so as to be relatively movable with respect to the upper punch P1, and elastically presses the outer peripheral portion of the cup-shaped shell material 10 against the die D1, as shown in the figure. The lower punch P2 is elastically held toward the upper punch P1, descends following the lowering of the upper punch P1, and when the upper punch P1 rises, the lower punch P2 rises by an elastic force and is moved from the die D1 to the cup-shaped shell material 10. It works to discharge. Then, the cup-shaped shell material 10 is deep-drawn by lowering the upper punch P1 and pushing the cup-shaped shell material 10 into the die D1. This deep drawing is performed in two stages, a first deep drawing process (FIG. 7A) and a second deep drawing process. Thereafter, the bottom pushing process (FIG. 8A), the outer diameter ironing process (FIG. 8B), the bottoming process (9 (A)), and the trimming process (FIG. 9B) are continued.
[0006]
First deep drawing step The upper punch P1 is lowered from the state shown in FIG. 6 as shown in FIG. 7A, whereby the cup-shaped shell material 10 is drawn and compared as shown in FIG. 10A. It becomes a cup-shaped cross section with a shallow bottom. Thereafter, the upper punch P1 moves backward and the lower punch P2 rises, and the cup-shaped shell material 10 is taken out.
[0007]
Second Deep Drawing Process As shown in FIG. 7 (B), the cup-shaped shell material 10 that has undergone the first deep drawing is inserted into the die D2, and further deep drawing is performed with the upper punch P3 to a size substantially equal to the final product. To do. In the first and second deep drawing steps, as can be seen from FIGS. 10A and 10B, the deep cornering is performed by setting the bottom corner R11 of the cup-shaped shell material 10 to a larger radius of curvature than the final product. It is designed to be accurate.
[0008]
As shown in FIG. 8 (A), the cup-shaped shell material 10 is inserted into the die D3 by the upper punch P4 for pressing the bottom, and the bottom corner R11 of the cup-shaped shell material 10 is formed at the outer periphery of the top end of the upper punch P4. Press to process into a corner R12 having a small radius of curvature as shown in FIG. The radius of curvature of the bottom corner R12 is substantially equal to the bottom corner R of the race which is the final product (FIG. 4).
[0009]
As shown in FIG. 8B, the cup-shaped shell material 10 is inserted into the die D4 by the upper punch P5 for ironing, and the outer peripheral surface of the cup-shaped shell material 10 is ironed by the die D4. The outer periphery of the upper end of the upper punch P5 for ironing has a radius of curvature that is the same as or smaller than the radius of curvature of the bottom corner R12 of the cup-shaped shell material 10, and the outer peripheral surface of the cup-shaped shell material 10 is within the ironing die D4. By pressing against the peripheral surface, the outer peripheral surface of the cup-shaped shell material 10 is finished to a predetermined outer diameter. This ironing process may also be performed in two stages: rough ironing and finishing ironing.
[0010]
At the same time, the stepped portion 14 is ironed at the opening end of the cup-shaped shell material 10 on the stepped surface of the outer periphery of the upper punch P5. The stepped portion 14 is ironed into a two-stage shape as shown in FIG. 10D, for example, in a thinning process in order to facilitate edge bending in a subsequent process. The outer stepped portion 14a of the stepped portion 14 is cut off in the subsequent edge cutting step, and the inner stepped portion 14b is bent inward in the subsequent edge bending process to form a flange.
[0011]
As shown in FIG. 9 (A), a bottomed cup-shaped shell material 10 is inserted into a die D5 by a bottom punching upper punch P6 and is received by a hollow bottom punching lower punch P7 while being received by an upper punch P6. Is lowered to punch out the center of the bottom of the cup-shaped shell material 10. Further, by this bottoming process, the flange 1a is formed on the bottom of the cup-shaped shell material 10 as shown in FIG.
[0012]
Trimming (edge cutting) process As shown in FIG. 9B, the cup-shaped shell material 10 is inserted into the die D6 by the upper punch P8 for edge cutting, and the upper punch P8 is lowered while being received by the lower punch P9 to form a cup shape. The edge of the opening end of the shell material 10 is cut. In this edge cutting, as shown in FIG. 10 (F), the outer stepped portion 14a of the stepped portion 14 is cut away, and only the inner stepped portion 14b with stable dimensional accuracy remains.
[0013]
After the post-process trimming step, the entire cup-shaped shell material 10 is quenched. Next, a tempering process is performed on the opening end portion of the cup-shaped shell material 10 where the inner stepped portion 14b is provided so that cracking does not occur even if the opening end portion is bent in a subsequent edge bending step, and then tumbling (tumbling process) is performed. ) Removes coloration due to quenching and annealing. Thereafter, the needle roller 4 with cage is inserted into the cup-shaped shell material 10 (see FIG. 5), and the inner step 14b at the opening end is bent to form the other flange 1b. The shell needle roller bearing manufactured in this way is assembled by press-fitting the race 1 into a holding hole formed in a housing or the like with a tightening margin.
[0014]
[Problems to be solved by the invention]
Conventional shell-type needle roller bearings may suffer from problems such as insufficient bearing life, poor acoustics during use, variations in pressure input required to press fit into a housing, etc. and excessive maximum pressure input. . One of the common causes is insufficient accuracy of the race. However, in the above-described conventional method for manufacturing a shell-shaped needle roller bearing raceway, no processing has been performed for the purpose of improving the surface roughness and shape accuracy of the raceway surface.
[0015]
The outer diameter ironing process in FIG. 8 is not a direct ironing process (inner diameter ironing process) on the inner peripheral surface. Rather, a large distortion is given to the cup-shaped shell material when the outer peripheral surface of the cup-shaped shell material is rubbed with a die in the outer diameter ironing process of FIG. There is a proportional relationship between the magnitude of this distortion and the surface roughness of the inner circumferential surface (track surface). The more the ironing process is performed on the outer peripheral surface of the cup-shaped shell material, the greater the surface roughness of the inner circumferential surface (track surface). Gets worse. FIG. 11 is a conceptual diagram showing the relationship between the magnitude of distortion imparted to the material by processing and the surface roughness, and shows that the surface roughness deteriorates as processing is performed on the material. Therefore, in order to improve the surface roughness and shape accuracy of the raceway surface, it is necessary to directly process the portion. In the tumbling process, the outer peripheral surface is improved in surface roughness, but the inner peripheral surface serving as the raceway surface is only improved to remove sludge generated by quenching, and the surface roughness is not improved so much.
[0016]
However, when the inner diameter surface of the cup-shaped material such as the shell-shaped needle roller bearing raceway is subjected to ironing, the ironing punch must be press-fitted from the opening end side. As a result, the metal material that plastically flows concentrates on the bottom corner of the material, so that the ironing allowance cannot be made large. Further, the outer periphery of the tip end of the ironing punch functions to form the bottom corner of the cup-shaped shell material, and therefore needs to have a small radius of curvature. Accordingly, the processing surface pressure becomes excessive, and there is a risk of causing galling. This galling surely induces rough surfaces.
[0017]
If the inner peripheral surface of the cup-shaped shell material is rubbed with a squeezing punch with a small radius of curvature at the outer periphery of the tip, the lubricant will be scraped off and seizure will occur, or the squeezing punch will have poor fluidity and part of the circumferential direction Scratching may occur. Further, only the galling portion abruptly increases the frictional resistance, causing resistance in the punching direction, and causing unevenness in the processing force in the circumferential direction of the ironing punch. This non-uniform working force eventually acts as a moment to rotate the ironing punch, which promotes the inclination of the ironing punch and degrades the accuracy of the surface roughness, roundness, cylindricity, etc. of the inner surface of the cup-shaped material Let
[0018]
An object of the present invention is to improve the surface roughness and shape accuracy of a raceway for a shell needle roller bearing.
[0019]
[Means for Solving the Problems]
In a shell-shaped needle roller bearing bearing ring having a flange bent toward the inner diameter side at least on one end side of a cylindrical raceway surface, the raceway surface is an ironing surface, and the surface roughness (Ra) is 0. 15 μm or less. Ironing is known as a field of sheet metal pressing that reduces the wall thickness of a workpiece by punching and dies to make the thickness uniform. Since the raceway surface of the shell needle roller bearing according to the present invention is an ironed surface, that is, a surface subjected to direct ironing, it is used for a conventional shell needle roller bearing in which ironing is performed only on the outer peripheral surface. Compared with the raceway, the surface roughness of the raceway surface and the shape accuracy such as cylindricity and roundness are improved. Here, the surface roughness is based on the centerline average roughness (Ra) defined in JIS B 0601.
[0020]
A deep drawing step of forming a steel plate blank into a cup-shaped shell material by deep drawing, a surface pressing step of pressing the bottom corner of the cup-shaped shell material to a predetermined radius of curvature, and the cup-shaped shell material In the manufacturing method of a ring for a needle roller bearing of a shell type, comprising: a stepping process for forming a stepped portion at the opening end of the opening by ironing; and an edge cutting process for cutting off a peripheral edge of the opening end. It is a manufacturing method of the raceway for shell type needle roller bearings which further has an ironing process of ironing the inner peripheral surface of the cup-shaped shell material after processing. In the manufacturing process of the bearing ring, by subjecting the inner peripheral surface of the cup-shaped shell material to ironing, it is possible to obtain a bearing ring for a shell needle roller bearing having a high dimensional accuracy of the raceway surface and good surface roughness.
[0021]
In the ironing step in the method of manufacturing the raceway for a shell needle roller bearing, the ironing punch having a predetermined outer diameter is inserted until it contacts the bottom of the cup-shaped shell material, and the cup-shaped shell material is the final product. The ironing process is performed by press-fitting into a die having an inner diameter substantially equal to the outer diameter of the race and pulling the ironing punch toward the opening side of the cup-shaped shell material. By ironing the cylindrical inner peripheral surface of the cup-shaped shell material from the opening end side of the cup-shaped shell material to the opening end side, the inner peripheral surface of the cup-shaped shell material is ironed. Realized. As a result, the intended purpose of improving the surface roughness and the shape accuracy of the raceway surface of the shell-shaped needle roller bearing raceway can be achieved.
[0022]
Here, the cup-shaped shell material includes both a material whose bottom is punched and a material which is not stamped. After finishing the various pressing and ironing processes such as face pressing at the bottom corner of this cup-shaped material, and performing the ironing process of the inner peripheral surface at the final stage, the ironed inner peripheral surface remains as it is Since it becomes the raceway surface of the raceway ring as the final product, the surface roughness and shape accuracy are maintained with high accuracy.
[0023]
A deep drawing step of forming a steel plate blank into a cup-shaped shell material by deep drawing, a stepping step of forming a stepped portion at the opening end of the cup-shaped shell material by ironing, and the cup-shaped shell material A bottom punching process for punching the bottom part, an edge cutting process for cutting off the peripheral edge of the opening end of the cup-shaped shell material, and a squeezing punch having a predetermined outer diameter are inserted until they contact the bottom of the cup-shaped shell material. Pressing the bottom corner of the cup-shaped shell material into a predetermined radius of curvature, and press-fitting the cup-shaped shell material into a die having an inner diameter substantially equal to the outer diameter of the raceway ring as the final product And an ironing process for ironing by pulling the ironing punch toward the opening side of the cup-shaped shell material. It is a Michiwa method of manufacturing.
[0024]
The ironing punch used for ironing is to perform the ironing process on the inner peripheral surface in the final process after the process of punching the bottom of the bottomed cup-shaped shell material to form the inward flange. Immediately before the ironing process, the corner R with the flange of the cup-shaped shell material is surface-pressed. Thereby, one ironing punch can serve as both a punch that presses the bottom corner R of the cup-shaped shell material and a punch that irons the inner peripheral surface. In addition, when the ironing punch is inserted into the cup-shaped shell material prior to the inner diameter ironing process, the surface pressing process can be performed at the same time, so that one process is substantially omitted, and the cycle time is shortened.
[0025]
In the method of manufacturing a raceway for a shell-type needle roller bearing, the ironing punch has an outer diameter that is substantially equal to the inner diameter of the raceway surface of the raceway that is the final product, and an outer diameter that increases with distance from the tip. It has a processing head which consists of a taper part which decreases gradually.
[0026]
Insert the ironing punch from the opening of the cup-shaped shell material to the back, bring the tip of the processing head into contact with the bottom of the cup-shaped shell material, and press the die into the die in a state where both are integrated, then the ironing punch The inner peripheral surface of the cup-shaped shell material is ironed by pulling out toward the opening side of the cup-shaped shell material. Since the outer diameter of the taper of the machining head gradually decreases as it moves away from the tip, excessive surface pressure is not generated on the cup-shaped shell material during ironing, preventing galling and chewing the lubricating oil. It is easy to insert and suppresses baking. In this specification, “substantially equal” is intended to include those within the range of normal processing tolerances.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 3. It should be noted that substantially the same parts or portions are denoted by the same reference symbols throughout the accompanying drawings to avoid duplicating description.
[0029]
FIG. 1 is a step-by-step illustration of the ironing process in the manufacturing process of a raceway for a shell needle roller bearing (see FIG. 5). The cup-shaped shell material 10 has substantially the same shape as that obtained in the above-described trimming step of FIG. 10F, and has an inward flange 1a at one end of the cylindrical inner peripheral surface 2 and the other end. The side is an open end 15. The open end 15 is a cylindrical end obtained by trimming the stepped portion 14. The cup-shaped shell material 10 can be manufactured through the steps shown in FIGS. 7 and 9 except the ironing step shown in FIG.
[0030]
As shown in FIG. 2A, the ironing punch 20 is substantially cylindrical and has a machining head 23 at the tip. The processing head 23 includes a tapered portion 21 and a tip portion 22. The tapered portion 21 is a conical taper surface having a larger diameter as it goes to the tip, in other words, a tapered outer surface whose outer diameter gradually decreases as it gets away from the tip. The outer diameter of the tip 22 is set to be substantially equal to the inner diameter of the raceway surface in the raceway ring as the final product. The outer peripheral surface of the tip portion 22 is a curved surface having a small curvature radius, and this curvature radius is equal to or smaller than the curvature radius of the bottom corner R12 of the cup-shaped shell material 10. The inner diameter of the inner peripheral surface 2 of the cup-shaped shell material 10 before the ironing process is set to be slightly smaller than the outer diameter of the tip 22 of the ironing punch 20.
[0031]
Prior to squeezing the inner peripheral surface 2 of the cup-shaped shell material 10 using the squeezing punch 20, as shown in FIG. The tip is brought into contact with the bottom flange 1 a of the cup-shaped shell material 10. At this stage, there is a gap between the ironing punch 20 and the inner peripheral surface of the cup-shaped shell material 10, and the relationship between the two is loose.
[0032]
The cup-shaped shell material 10 / the ironing punch 20 thus integrated is press-fitted into the cylindrical die hole 31 of the die 30 as shown in FIG. The inner diameter of the die hole 31 is set to be substantially equal to a predetermined outer diameter of the race which is the final product. Then, the outer diameter of the cup-shaped shell material 10 is set slightly larger than the inner diameter of the die hole 31. Therefore, when the cup-shaped shell material 10 is press-fitted into the die hole 31, the outer peripheral surface of the cup-shaped shell material 10 is constrained to reduce the outer diameter, and the inner diameter is also reduced accordingly, thereby forming a predetermined ironing allowance. .
[0033]
Next, as shown in FIG. 2B, a flat stopper 40 is set on the die 30, and the upper end of the cup-shaped shell material 10 is brought into contact with the lower surface of the stopper 40. The stopper 40 prevents the cup-shaped shell material 10 from coming out of the die hole 31 due to the ironing load.
[0034]
Subsequently, as shown in FIG. 2C, the ironing punch 20 is raised and pulled out from the cup-shaped shell material 20 to perform ironing. At this time, the processing head 23 of the ironing punch 20 moves from the flange 1a side of the cup-shaped shell material 10 toward the opening end 15 side, and the inner peripheral surface 2 is ironed. When the ironing of the inner peripheral surface 2 is finished, the ironing punch 20 is extracted above the stopper 40 as shown in FIG.
[0035]
The processing head 23 of the ironing punch 20 has a conical taper shape, and the tip portion 22 having the largest diameter is ironed in order from the inner end of the cup-shaped shell material 10 toward the opening end 15 from the inner end of the flange 1a. To do. In this case, by reducing the taper angle of the taper portion 21 of the machining head 23, it is possible to avoid an excessive surface pressure during ironing.
[0036]
Since the processing head 23 of the ironing punch 20 has a conical shape, the inclination of the ironing punch 20 with respect to the cup-shaped shell material 10 changes even if unevenness occurs in the processing surface pressure distribution in the circumferential direction of the processing part during ironing. It is difficult to cause galling. Therefore, surface roughness of the inner peripheral surface (track surface) 2 of the cup-shaped shell material is not induced.
[0037]
Since the taper portion 21 of the processing head 23 is gradually reduced in diameter in the ironing processing direction, it is easy to bite the lubricating oil into the processing portion due to the wedge effect, and seizure is prevented.
[0038]
Since the metal material that plastically flows along with the ironing process flows toward the opening end 15, there is a place for escape of excess metal material, and there is no fear of troubles such as bottoming out of tools due to product variations.
[0039]
With the synergistic effect of the above advantages, stable inner diameter ironing of the cup-shaped shell material 10 by the ironing punch 20 is realized, and the surface roughness, roundness, and cylindricity of the ironed inner peripheral surface (track surface) 2 are realized. Etc. are improved.
[0040]
In this embodiment, the inner diameter ironing of the cup-shaped shell material is executed in the final process of manufacturing the cup-shaped shell material, and the accurately finished inner peripheral surface is provided as it is as the raceway surface of the bearing ring as the final product. The cup-shaped shell material may be a bottomed cup-shaped shell material. In this case, the ironing process by the ironing punch on the inner peripheral surface of the cup-shaped shell material is performed in the same manner as described above with reference to FIG. be able to.
[0041]
Further, the inner diameter ironing step may be executed immediately after the step of pressing the bottom corner of the flange at one end of the cylindrical inner peripheral surface of the cup-shaped shell material into a small radius of curvature. For example, as described below, it is also effective to manufacture a bearing ring by the process shown in FIG.
[0042]
A cup-shaped shell material 10 shown in FIG. 3A is a bottomed cup-shaped material obtained by a deep drawing process, and the bottom corner is a corner R portion 11 having a large radius of curvature. The cup-shaped shell material 10 is bottomed as shown in FIG. 3B, stepped and trimmed to form the flange 1a at the corner R portion 11, and the stepped portion 14 at the open end 15. Form. Thereafter, as shown in FIG. 3C, the cup-shaped shell material 10 with the punch 20 inserted to the bottom is press-fitted into the die hole 31 of the die 30. The die hole 31 in FIG. 3C is a bottomed hole. The flange 1a of the cup-shaped shell material 10 is brought into contact with the bottom portion 32 of the die hole 31, and the corner R11 is pressed by the outer periphery 22 of the tip end of the punch 20. Then, the corner R11 is processed into a corner R12 having a small predetermined curvature radius. When the punch 20 whose surface pressing is finished is raised, the inner peripheral surface of the cup-shaped shell material 10 is ironed by the processing portion 23 of the punch 20 in the same manner as in FIG.
[0043]
As shown in FIG. 3, the number of punches for manufacturing the bearing ring can be reduced by performing surface pressing and inner diameter ironing of the cup-shaped shell material 10 with the common punch 20, and the number of processing steps using the punch can also be reduced. Less.
[0044]
【The invention's effect】
In order to verify the effect of the present invention, the surface roughness, cylindricity, and roundness of the cylindrical inner peripheral surface of the steel plate cup-shaped shell material before and after ironing were measured, and the following experimental data was obtained.
[0045]
Experiment 1 (Surface roughness Ra)
The result of measuring the surface roughness Ra (μm) before and after ironing was measured for the inner circumferential surface of the cup-shaped shell material in three equal positions.
[0046]
Before ironing (0.3366), (0.3671), (0.3851)
After ironing (0.0319), (0.0328), (0.0409)
Since the surface roughness before ironing corresponds to the surface roughness of the conventional product raceway surface, the above experimental results show that the surface roughness of the product of the present invention is improved to about 1/10 of the conventional product. .
[0047]
Further, FIG. 4 shows one roughness curve of the inner peripheral surface of the cup-shaped shell material in which the surface roughness before ironing is Ra = 0.3366 and the surface roughness after ironing is Ra = 0.0319. Shown in FIG. 4 (A) is before ironing and FIG. 4 (B) is after ironing, and it can be clearly seen that the surface roughness is improved from the comparison between the two. The surface roughness Ra of the raceway surface is preferably 0.15 or less for practical use, but the average surface roughness Ra ≦ 0.1 is achieved by ironing the inner peripheral surface of the cup-shaped shell material. it can.
[0048]
Experiment 2 (cylindricity CY)
The result of measuring the cylindricity CY (μm) of the cup-shaped shell material is as follows. Here, the cylindricity is defined as the maximum radial distance in each radial plane between the cylinder inscribed in the cylindrical surface and each point on the surface.
[0049]
Before ironing 18.2
After ironing 15.0
From this experimental result, it was confirmed that the cylindricity was sufficiently improved.
[0050]
Experiment 3 (Roundness)
The result of measuring the roundness at the position of the inner circumferential surface of the cup-shaped shell material in three equal parts is as follows. Here, the roundness is defined as the maximum radial distance between a circle inscribed in a circular line and each point on the circular line.
[0051]
Before ironing (10.8μm), (8.4μm), (7.2μm)
After ironing (4.4μm), (4.2μm), (4.5μm)
Since the roundness before the ironing process corresponds to the roundness of the conventional product raceway surface, it can be seen from this experimental result that the roundness has been improved about twice.
[0052]
As described above, according to the present invention, it is possible to improve the surface roughness and shape accuracy of the raceway for a shell needle roller bearing.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view for explaining a production method of the present invention,
(A) is when the cup-shaped shell material is inserted,
(B) is when installing the stopper.
(C) During the ironing process,
(D) shows after ironing.
FIG. 2A is a cross-sectional view of a iron punch and a cup-shaped shell material;
(B) It is sectional drawing of the state inserted in the ironing punch and the cup-shaped shell raw material.
FIG. 3 is a cross-sectional view for explaining another embodiment of the present invention,
(A) is a cup-shaped shell material sectional view during deep drawing,
(B) is a cross-sectional view of the cup-shaped shell material after the bottoming process and the trimming process,
(C) It is sectional drawing of the bottom pushing process just before ironing.
FIG. 4A is a roughness curve diagram before ironing of the inner peripheral surface of a cup-shaped shell material;
(B) is the roughness curve figure after the ironing process of the internal peripheral surface of a cup-shaped shell raw material.
FIG. 5 is a partial sectional view of a shell needle roller bearing.
FIG. 6 is a cross-sectional view of the press apparatus in a state where a blank is set.
7A is an enlarged cross-sectional view in the first deep drawing step of the press device shown in FIG.
(B) is an expanded sectional view in the 2nd deep drawing process of the press apparatus shown by FIG.
8A is an enlarged cross-sectional view in the bottom pushing process of the pressing apparatus shown in FIG.
(B) is an expanded sectional view in the outer diameter ironing process of the press apparatus shown by FIG.
FIG. 9A is an enlarged cross-sectional view of the press apparatus shown in FIG.
(B) is an expanded sectional view in the trimming process of the press apparatus shown by FIG.
10 (A) is an enlarged cross-sectional view of a cup-shaped shell material in the step shown in FIG. 7 (A);
(B) is an enlarged cross-sectional view of a cup-shaped shell material in the step shown in FIG.
(C) is an enlarged cross-sectional view of a cup-shaped shell material in the step shown in FIG.
(D) is an enlarged cross-sectional view of a cup-shaped shell material in the step shown in FIG.
(E) is an enlarged cross-sectional view of a cup-shaped shell material in the step shown in FIG.
FIG. 10F is an enlarged cross-sectional view of the cup-shaped shell material in the process shown in FIG.
FIG. 11 is a conceptual diagram showing the relationship between distortion due to processing and surface roughness.
[Explanation of symbols]
1 bearing ring 1a, 1b flange 2 raceway surface (inner circumferential surface of cup-shaped shell material)
3 Needle roller 4 Cage 10 Cup-shaped shell material 11 Bottom corner R
12 Bottom corner R
14 Stepped portion 15 Open end portion 20 Punch 21 Tapered portion 22 Tip portion 23 Processing head 30 Die 31 Die hole 40 Stopper

Claims (3)

A deep drawing process of forming a steel sheet blank into a cup-shaped shell material by deep drawing;
A surface pressing step of pressing the bottom corner of the cup-shaped shell material to a predetermined radius of curvature;
A stepping step of forming a stepped portion at the opening end of the cup-shaped shell material by ironing; and
An edge cutting step of cutting a peripheral edge of the opening end,
In a method of manufacturing a ring for a shell needle roller bearing having
An inner diameter ironing step of ironing the inner peripheral surface of the cup-shaped shell material after the edge cutting step;
In the inner diameter ironing step, an ironing punch having a predetermined outer diameter is inserted until it abuts against the bottom of the cup-shaped shell material, and the cup-shaped shell material has an inner diameter substantially equal to the outer diameter of the raceway ring as the final product. A method for manufacturing a raceway for a shell-type needle roller bearing, wherein ironing is performed by press-fitting into a die and pulling out the ironing punch toward the opening side of the cup-shaped shell material. A deep drawing process of forming a steel sheet blank into a cup-shaped shell material by deep drawing;
A stepping step of forming a stepped portion at the opening end of the cup-shaped shell material by ironing; and
A bottoming step of punching a bottom portion of the cup-shaped shell material;
An edge cutting step of cutting the peripheral edge of the open end of the cup-shaped shell material;
Inserting a ironing punch having a predetermined outer diameter until it abuts against the bottom of the cup-shaped shell material, and pressing the bottom corner of the cup-shaped shell material to a predetermined radius of curvature,
The cup-shaped shell material is pressed into a die having an inner diameter substantially equal to the outer diameter of the raceway ring, which is the final product, and the inner diameter ironing is performed by ironing by pulling the iron punch toward the opening side of the cup-shaped shell material. A process for producing a raceway for a shell-type needle roller bearing. The ironing punch has a machining head including a tip portion having an outer diameter substantially equal to an inner diameter of a raceway surface in a raceway ring as a final product, and a tapered portion whose outer diameter gradually decreases as the distance from the tip portion is increased. The manufacturing method of the raceway for shell type needle roller bearings according to claim 1 or 2 .

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