JP4284951B2 - Method of manufacturing bearing ring for ball bearing - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is used as a constituent member of the ball bearings, moreover relates to the production how ball bearing races with a trajectory of the concave shape having a curved surface.
[0002]
[Prior art]
Conventionally, a bearing ring for a rolling bearing such as a ball bearing has a problem that its life is short due to repeated load. In response to this problem, the present inventors heat-treated a blank for a raceway member made of carbon steel for machine structure machined into a predetermined shape to harden the raceway part, and then turned or ground the raceway part. Proposed a method for manufacturing a bearing race member that has been subjected to roller burnishing on the raceway portion, and has a hardness of at least 0.2 mm deep from the surface of the raceway portion to be hardened to Hv800 or higher, and has already been filed. (Japanese Patent Application No. 2002-138970, filed on May 14, 2002). In this way, by applying roller burnishing to the raceway, a longer life is achieved than in the past.
[0003]
[Problems to be solved by the invention]
However, in the above manufacturing method, as shown in FIG. 4, not only the roller burnishing sphere 12 is brought into rolling contact with the concave raceway 11 having a curved surface in the circumferential direction but also perpendicular to the circumferential direction. Therefore, there is a problem that a processing method is complicated and a high level of technology is required to obtain dimensional accuracy. In addition, there is also a problem that the number of processes is large because a roller burnishing process is performed after finishing a track having a curved surface by turning or grinding.
[0004]
The present invention has been made in view of such circumstances, and aims to provide a manufacturing how ball bearing races Ru can be the dimensional accuracy easily produce long-life ball bearing raceway good And
[0005]
[Means for Solving the Problems]
The inventors of the present invention have intensively studied to develop a technique for easily manufacturing a long-life bearing ball bearing ring having a concave raceway having a curved surface. In that process, paying attention to the point that the object of roller burnishing is a concave-shaped track having a curved surface, a ceramic ball having a shape that matches the shape of the track or an intermediate material subjected to heat treatment We found that a ball bearing ring with good dimensional accuracy and a long life could be easily obtained by roller burnishing using steel balls harder than the raceway surface , and the present invention was completed. It was.
[0006]
A method for manufacturing a ball bearing race for a ball bearing according to the present invention is a method for manufacturing a ball bearing race for a ball bearing having a concave raceway having a curved surface, and at least the surface of the raceway is made of a metal material. leave produce an intermediate material heat treatment orbit semi-circular cross section of the shape smaller than the shape of the track is formed is performed, the roller having a final trajectory shape and same shape the trajectory of the intermediate material By pressing a ball made of ceramics for burnishing or a steel ball harder than the surface of the intermediate material subjected to the heat treatment, it is brought into contact with the surface while relatively rolling along the track. maximum residual compressive stress at a depth of shear stress acts 800MPa or more and / or stiffness to the above Hv800 the bearing during use a depth in the range of 0.08~0.3mm It is characterized.
[0007]
With the manufacturing method described above, a ball made of ceramic for roller burnishing or a steel ball harder than the track surface of the intermediate material subjected to heat treatment is pressed against the track of the intermediate material that is the workpiece. Since the rolling contact is made along the track, the size can be expanded while finishing the track of the intermediate material to be smooth. Therefore, it is possible to easily manufacture a recess-shaped track having a curved surface that is difficult to manufacture with high accuracy. Further, since the roller burnishing is performed, residual stress can be applied to the raceway surface, the hardness can be increased, and as a result, a long-life ball bearing raceway with high fatigue strength can be manufactured. Further, according to this manufacturing method, the final recess shape of the raceway becomes a semicircular cross-section by roller burnishing, so that a raceway suitable for a ball bearing can be provided.
[0008]
In the present invention, the "same shape" includes those shapes of the trajectory of the ball bearing raceway after roller burnishing is slightly smaller by the spring back.
Further, in the present invention, the roller burnishing is a kind of processing for plastic processing of the surface, and is a method in which the convex portions on the surface are locally pushed by a ball.
[0009]
The ball bearing race ring manufacturing method of the present invention is the above-described ball bearing race ring manufacturing method, wherein the ball is made of a ceramic ball for roller burnishing, or steel harder than the raceway surface of the intermediate material subjected to heat treatment. pressing manufacturing of the ball in the hydraulic pressure that features a Rukoto.
[0010]
Further, in the above manufacturing method, and balls as rolling elements constituting the roller burnishing ceramic balls or hard steel ball and ball bearings than the heat treatment is performed intermediate material of the raceway surface for processing it is preferably the same shape. If it becomes like this, since the track | orbit of the bearing ring actually used as a ball bearing and the ball | bowl as a rolling element correspond, there exists an advantage that it becomes a favorable ball bearing. Here, the "same shape", to those on the design dimension was completely actually manufactured even in the same shape including those where there is an error.
[0011]
Further, in the above-described method for manufacturing the ball bearing raceway, a hard steel ball than ceramic balls or the heat treatment is performed intermediate material of the raceway surface prior km over La burnishing for processing, of the intermediate material yet good as having an axial curvature 99.995% following the curvature of the shape of the orbit of a semicircular cross section. With the above configuration, since the relationship between the size of the sphere for roller burnishing and the size of the track of the intermediate material that is the workpiece is appropriate, the track can be formed with particularly high dimensional accuracy, and the track surface is particularly smooth. Can be.
[0012]
Further, in the above-described method for manufacturing the ball bearing raceway, a hard steel ball than ceramic balls or the heat treatment is performed intermediate material of the raceway surface prior km over La burnishing for processing, of the intermediate material but it may also as having a 1~3μm radius of curvature greater than the axial curvature radius of the shape of the track. With the above configuration, since the relationship between the ball for roller burnishing and the dimension of the track of the intermediate material that is the workpiece becomes appropriate, the track can be formed with particularly high dimensional accuracy and the track surface can be particularly smooth. can do.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Below, the manufacturing method of the bearing ring for ball bearings of this invention is concretely demonstrated based on drawing using the inner ring for ball bearings which is the embodiment as an example.
[0016]
First, as shown in FIG. 1 and FIG. 2, a known forging, turning, heat treatment, and rough polishing are applied to a material made of bearing steel to form a raceway 1 having a semicircular cross section in the outer circumferential direction. The inner ring material 2 is produced. This track 1 is smaller than the size of the semicircular cross section of the final track 3 (in the figure, the broken line 3 indicates the final track size).
[0017]
Then, as shown in FIG. 3, larger than a semicircular cross section of the inner ring material 2, the roller burnishing ceramic balls for processing (sphere) 4 having a final inner semi-circular cross section and same shape The inner ring material 2 is pressed against the track 1 with a strong pressure. In this state, the roller burnishing process is performed on the raceway 1 of the inner ring material 2 by fixing the roller burnishing ball 4 side and rotating the inner ring material 2 around the bearing rotation axis. As a result, the semicircular cross-sectional shape of the track 3 can be expanded to the final dimensions, and the surface of the track 3 can be smoothed. Further, depending on the conditions of the roller burnishing, a residual compressive stress of 800 MPa or more at a depth (usually about 0.08 to 0.3 mm from the surface) at which the maximum shear stress acts when the bearing is used, or the hardness Hv is set. Since it can be 800 or more, fatigue strength can be increased. In this way, an inner ring for a ball bearing can be manufactured.
[0018]
Here, bearing steel is used as the material of the intermediate material 2, the roller burnishing conditions are ceramic balls (diameter 6.3mm), workpiece rotation speed 100m / min, tool feed 0.1mm / rev, machining fluid circulates Confirm that the semi-circular curvature radius is 2 μm and the surface roughness Rz is 0.2 μm or less when the oil pressure of the roller burnishing tool is 1000 N. is doing. It has also been confirmed that when the oil pressure is 780 N under the same conditions, the radius of curvature of the semicircular cross section is 1 μm larger and the surface roughness Rz is 0.2 μm or less.
[0019]
In said manufacturing method, it is preferable that the curvature of the ball | bowl 4 is set to 99.995% or less of the axial direction curvature in the cross-sectional semicircle shape of the inner ring | wheel raw material 2. FIG. Especially preferably, it is 99.992-99.994%. This is because, when a material having a large axial curvature is used, the dimensional accuracy may be lowered or the surface roughness may be increased.
[0020]
Moreover, it is preferable to use a curvature radius of the ball 4 that is 1 to 3 μm larger than the curvature radius in the axial direction in the semicircular cross section of the inner ring material 2. If it is not within such a range, the dimensional accuracy may be lowered or the surface roughness may be increased.
[0021]
The life test was conducted using the inner ring for the ball bearing obtained as described above and the inner ring for the ball bearing obtained by rough polishing, finishing, and superfinishing without performing the roller burnishing. As a result, it was confirmed that the life of the inner ring for ball bearings obtained as described above was about 2.2 times longer.
[0022]
(Other matters)
In the above description, the method of performing the roller burnishing process by rotating the inner ring material 2 has been described. However, the ceramic balls 4 may be rolled and contacted along the track while the inner ring material 2 is fixed.
Moreover, although the ceramic thing was used as the ball | bowl 4 for roller burnishing processing, if it is harder than the track | orbit 1 surface of the intermediate material 2 to process, there will be no restriction | limiting in particular, For example, a high hardness steel ball May be used.
Furthermore, although the bearing steel is used as the material of the intermediate material 2 in the above, the present invention is not limited to this, and various metal materials conventionally used as the material of the bearing ring for the rolling bearing may be used.
In the above, the case where the roller burnishing process is performed after the rough polishing has been described, but the present invention is not limited to this, and if there is no problem such as damage to the roller burnishing process, The roller burnishing may be performed immediately after the heat treatment without performing rough polishing.
Furthermore, in the above description, the inner ring for the ball bearing has been described. However, the outer ring can be manufactured in the same manner.
[0023]
【The invention's effect】
As described above, according to the method of manufacturing a ball bearing raceway of the present invention, in rolling contact with and along said balls for roller burnishing its orbit in a state pressed against the raceway of the intermediate material is a workpiece Therefore, it is possible to easily manufacture a long-life ball bearing ring for a ball bearing.
[0024]
Moreover, in the manufacturing method described above, since the ball for roller burnishing is used, a raceway suitable for a ball bearing can be manufactured. The roller burnishing and Ball of rolling elements constituting the ball and ball bearings for processing a same shape, matching and Ball as a raceway and the rolling elements of the bearing ring is in when actually used as a ball bearing Therefore, it is possible to provide a ball bearing having a very good dimension.
[0025]
Furthermore, the curvature of the ball for roller burnishing and the curvature of the track of the intermediate material that is the workpiece, or the curvature radius of the ball for roller burnishing and the radius of curvature of the track of the intermediate material that is the workpiece are specified. If the above relationship is satisfied, the final track can be formed with particularly high dimensional accuracy, and the track surface can be made particularly smooth.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing an intermediate material used in a method for manufacturing a bearing ring for rolling bearings (an inner ring for ball bearings) according to the present invention.
FIG. 2 is a cross-sectional view of the intermediate material shown in FIG.
FIG. 3 is a schematic cross-sectional view for explaining a method for manufacturing a rolling bearing race (inner ring for ball bearing) according to the present invention.
FIG. 4 is a cross-sectional view for explaining a conventional roller burnishing process.
[Explanation of symbols]
1 Track 2 Intermediate Material 3 Final Track 4 Ceramic Ball

Claims (7)

A method of manufacturing a ball bearing ring for ball bearings having a concave raceway having a curved surface, and at least the surface of the raceway is made of a metal material, and having a semicircular cross-section having a shape smaller than the final raceway shape in advance. leave produce an intermediate material orbit was forming heat treatment is performed, ceramic balls or the heat treatment facilities for roller burnishing with the final trajectory shape and same shape the trajectory of the intermediate material In a state where a steel ball harder than the surface of the intermediate material is pressed, it is brought into contact with the rolling while relatively along the track so that the depth is in the range of 0.08 to 0.3 mm from the surface. the ball bearing manufacturing method for a bearing ring, characterized in that the residual compressive stress in a depth acting maximum shear stress when a certain bearing using more and / or stiffness 800MPa than Hv800   2. The ball bearing race according to claim 1, wherein a ceramic ball for roller burnishing or a steel ball harder than a raceway surface of the intermediate material subjected to the heat treatment is pressed with hydraulic pressure. A method for manufacturing a bearing ring for ball bearings. 2. The ball bearing race according to claim 1, wherein a ball made of ceramic and a ball made of steel harder than the raceway surface of the intermediate material subjected to the heat treatment or the ceramic ball for the roller burnishing are configured. the ball bearing manufacturing method for a bearing ring, characterized in that and the balls as the rolling elements are the same shape.   The ball bearing race according to any one of claims 1 to 3, wherein the ball made of ceramic for roller burnishing or a ball made of steel harder than the raceway surface of the intermediate material subjected to the heat treatment. Is a method for manufacturing a bearing ring for ball bearings having a curvature of 99.995% or less of the axial curvature of the semi-circular raceway shape of the intermediate material.   The ball bearing race according to any one of claims 1 to 3, wherein the ball made of ceramic for roller burnishing or a ball made of steel harder than the raceway surface of the intermediate material subjected to the heat treatment. However, the manufacturing method of the bearing ring for ball bearings has a curvature radius which is 1 to 3 μm larger than the curvature radius in the axial direction of the shape of the raceway of the intermediate material.   6. The ball bearing race according to claim 1, wherein the intermediate material is produced by subjecting a material made of bearing steel to forging, cutting, and heat treatment. A method for producing a bearing ring for ball bearings.   The ball bearing race according to any one of claims 1 to 5, wherein the intermediate material is produced by subjecting a material made of bearing steel to forging, cutting, heat treatment and rough polishing. A method for manufacturing a bearing ring for ball bearings, wherein

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