JP2001187917A - Double row spherical roller bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a double row spherical roller bearing whose thermal deformation of a guide ring is suppressed, that is caused by hardening and tempering treatment. SOLUTION: A manufacturer produces a guide ring 13 of specified measurement and shape by forging, cutting and the like and then oil-hardens the guide ring 13 with specified heating treatment and hardening temperature. In such a case, some camber or distortion occurs at the guide ring 13 due to uneven cooling, etc., at the time of hardening. Afterward, the manufacturer fits the guide ring 13 to a cylindrical first correction mold 31. The guide ring 13 is sandwiched by a circular second correction mold 33 and a disc-like third correction mold 35 from upper and lower sides. Next, the manufacturer carries current to a high frequency heating coil 31 through a tempering control device, and heats the guide ring 13 to a specified tempering temperature while watching it through a thermometer 39. The guide ring 13, temporarily showing plasticity at its system, is corrected in its camber or distortion in the first to third correction molds 31, 33, 35.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-row spherical roller bearing used for supporting a rotary shaft and the like, and more particularly to a technique for facilitating the manufacture of guide wheels.

[0002]

2. Description of the Related Art Double-row spherical roller bearings are frequently used as self-aligning bearings in cases where misalignment between the shaft and the housing is unavoidable, or where the rotating shaft is likely to bend by vibrating machines or the like. Have been. The double-row spherical roller bearing includes an outer ring having a concave spherical track whose center of curvature is the bearing center, an inner ring having two rows of tracks, and two rows of rollers disposed between the tracks of the inner and outer rings. A predetermined intersection angle is allowed between the center axis of the outer ring and the center axis of the inner ring. In general, a double row spherical roller bearing often uses a guide wheel together with a retainer in order to prevent skew of the rollers. The guide wheel is a thin ring-shaped component made of high carbon chromium bearing steel or the like, and is disposed on the inner ring side or the outer ring side of the cage.

[0003] The guide rollers are subjected to a surface hardening treatment in order to prevent abrasion because the rolling rollers are in sliding contact with the side surfaces. As a surface hardening method for guide wheels, a tufftriding treatment has been generally adopted in the past. However, this method has a very shallow hardening depth (about 0.005 to 0.02 mm).
When an impact or heavy load is applied to the guide wheel in a vibration environment or the like, surface peeling may occur. Further, since a cyanide salt is used in the tuftride treatment, there is a problem in working hygiene, and it has been difficult to treat a highly toxic waste liquid. Therefore, quenching and tempering treatments have been partially adopted as a surface hardening method instead of the tuftride treatment. According to the quenching / tempering process, a relatively deep portion of the guide wheel (0.03 to
0.5mm)
There is no need to use highly toxic chemicals as in the case of the tuftride treatment.

[0004]

However, when quenching / tempering treatment is performed on a thin guide wheel, so-called heat treatment deformation often occurs, and when the guide wheel is directly incorporated, the bearing may not rotate normally. . For this reason, the quenched and tempered guide wheels need to be finished to a regular size and shape by grinding, and the number of working steps and manufacturing costs have been increased. The present invention has been made in view of the above circumstances, and has as its object to provide a double-row spherical roller bearing using a guide wheel having high hardness and high dimensional accuracy without performing mechanical processing after heat treatment.

[0005]

In order to solve the above problems, according to the first aspect of the present invention, there is provided an outer ring having a concave spherical orbit having a center of curvature as a center of a bearing, an inner ring having two rows of orbits, A double-row spherical roller bearing comprising two rows of barrel rollers disposed between raceways of the inner and outer rings via a retainer and a guide wheel, wherein the guide wheel has an outer peripheral surface and an inner peripheral surface. A quenching or tempering treatment in which at least one of the face and the end face is restrained is proposed.

According to the present invention, for example, by performing quenching or tempering in a straightening mold, the heat treatment deformation of the guide wheel can be suppressed to an allowable limit or less.

According to the second aspect of the present invention, the outer ring having a concave spherical track whose center is the center of curvature of the bearing, the inner ring having two rows of tracks, and the inner and outer rings via a retainer and a guide wheel. The present invention proposes a double-row spherical roller bearing provided with two rows of barrel-shaped rollers disposed between the tracks, wherein the guide wheels are subjected to a quenching treatment in a high-pressure gas atmosphere.

According to the present invention, by using a high-pressure gas as a quenching refrigerant, the cooling of the work is performed uniformly and quickly as compared with oil quenching or the like. It is kept below the allowable limit.

According to the third aspect of the present invention, the inner and outer rings have an outer ring having a concave spherical track whose center of curvature is the center of the bearing, an inner ring having two rows of tracks, and a retainer and a guide wheel. The present invention proposes a double-row spherical roller bearing having two rows of barrel rollers disposed between the tracks, wherein the guide wheels have been subjected to austempering.

According to the present invention, for example, by using a molten salt or the like as a quenching refrigerant, the work can be cooled more uniformly and quickly than oil quenching or the like. The bainite transformation, which is a diffusion transformation due to the isothermal transformation, is combined with this, so that a guide wheel having high toughness and heat treatment deformation suppressed to an allowable limit or less can be obtained.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a half longitudinal sectional view showing a double row spherical roller bearing according to an embodiment of the present invention. In the figure, a double-row spherical roller bearing includes an outer race 1 having a concave spherical raceway 3 whose center of curvature is a bearing center, an inner race 5 having two rows of raceways 7, a raceway 3 of the outer race 1 and the inner race 5, And two rows of barrel-shaped rollers (hereinafter simply referred to as rollers) 9 disposed between the guide wheels 13 and a guide wheel 13 having a tapered cross section between the cage 11 and the two rows of raceways 7 on the inner and outer ring 5 side. Is held.
The guide wheel 13 has a shape shown in FIG. 2 and faces the retainer 11 with a gap. When the double row spherical roller bearing is incorporated in a machine, a means for preventing falling as described in Japanese Patent Application Laid-Open No. Hei 5-157116 is required in order to prevent the roller 9 from falling off the press holder 11. However, since it is not directly related to the gist of the invention, the illustration and the like are omitted.

In the first embodiment, the guide wheels 13 are
2 (high carbon chromium bearing steel) as a raw material in the following procedure. That is, the manufacturing worker first manufactures the guide wheel 13 having a predetermined size and shape by forging, cutting, or the like, and then performs a predetermined heat treatment (for example, one heat treatment at 1113 ° K).
The guide wheel 13 is oil-hardened at a quenching temperature (for example, 333 ° K) for 3 minutes). At this time, the guide wheel 13 is slightly warped or distorted due to uneven cooling or the like during quenching. Thereafter, the manufacturing worker fits the guide wheel 13 into the cylindrical first correction mold 31, as shown in FIG.
The guide wheel 13 is provided with a predetermined pressure (for example, 1 ton) by the annular second correction mold 33 and the disc-shaped third correction mold 35.
Is pressed from above and below. In the case of the present embodiment, the first to third correction dies 31, 33, 35 are made of ceramic. In FIG. 3, the member indicated by reference numeral 37 is the first correction mold 31.
A high-frequency heating coil disposed on the outer periphery of the device is a non-contact type thermometer, and is connected to a tempering control device (not shown).

Next, the manufacturing worker energizes the high-frequency heating coil 37 via the tempering control device, and monitors the guide wheel 13 at a predetermined tempering temperature (520 to 770 ° in this embodiment) while monitoring with the thermometer 39. Heat to K). As a result, in the guide wheel 13, the solute carbon precipitates and diffuses as ε-carbide, and the martensite structure changes from tetragonal to cubic to improve toughness. On the other hand, since the guide wheel 13 temporarily shows plasticity in its structure during the tempering process,
Warpage and distortion are corrected in the first to third correction molds 31, 33, 35. In the present embodiment, each correction mold 31, 33,
Since a ceramic having a linear expansion coefficient of about 1/5 of steel is used as the material of 35, the guide wheel 13 is compressed and straightened by the straightening dies 31, 33, and 35 with strong pressure during tempering.

In the first embodiment, by adopting such a tempering method, 1.5 mm from the surface of the guide wheel 13 is obtained.
While obtaining a hardness of HRC 50 or more at the (core) portion, thermal deformation could be suppressed to a very small value. FIG.
Using a guide wheel 13 made of J2 or S48C (carbon steel for machine structural use) as a material, the amount of deformation (warpage) after performing the correction tempering of the present embodiment and the conventional normal tempering is shown in a graph. A and B are guide wheels 13 made of SUJ2
This is an example in which straightening and tempering were performed on C.D.
E and F are examples in which normal tempering is performed on the guide wheel 13 made of SUJ2, and G and H are examples in which S48C is used.
This is an example in which normal tempering is performed on a guide wheel 13 made of a material. As can be seen from this graph, the warpage was about 0.2 mm when the normal tempering was performed, but the warpage was suppressed to 0.05 mm or less when the corrective tempering was performed.

Next, the second and third embodiments using no correction mold will be described. In these embodiments, a predetermined heat treatment (for example, 1113) is performed on a workpiece similar to the first embodiment.
(１３K for 13 minutes), and then the quenching method was changed. That is, the second embodiment corresponds to the second aspect in which quenching is performed in a high-pressure gas atmosphere.
High pressure gas (in this embodiment, 1 MPa
Helium gas) was used. The third embodiment corresponds to the third aspect of the invention in which an austempering process is performed. The third embodiment uses a molten salt at a predetermined temperature (573 ° K in the present embodiment) for a predetermined time (60 minutes in the present embodiment). ) And isothermal holding.

FIG. 7 is a graph showing the amount of warpage of the guide wheel 13 due to quenching. As can be seen from this figure, in the oil quenching (a) of the first embodiment, the warpage exceeds 0.2 mm. On the other hand, in the quenching (b) of the second embodiment and the quenching (c) of the third embodiment, both were able to be reduced to 0.1 mm or less.

The result is that, in the second embodiment, the use of the high-pressure gas as the cooling medium allows the work to be cooled more uniformly and quickly than in the conventional oil quenching, resulting from uneven cooling. This is because deformation due to heat treatment can be suppressed to a small value. In the second embodiment, the surface hardness after quenching is 83
5Hv is obtained, and even after performing the tempering process,
The surface hardness required for the guide wheel 13 was sufficiently secured.
In the second embodiment, since there is no need to perform cleaning and drying after quenching, there is an advantage that the manufacturing time and the number of steps can be reduced.

Further, in the third embodiment, the use of a molten salt having a high cooling ability and not causing a vapor film stage at the time of cooling in the cooling medium makes it possible to cool the work more uniformly than in the conventional oil quenching. This is because the heat treatment is performed quickly and the heat treatment deformation due to the non-uniform cooling is kept small. Further, in oil quenching, martensitic transformation, which is a non-diffusion transformation with a large lattice distortion, occurs, whereas in austempering, bainite transformation, which is a diffusion transformation, occurs.
This difference in allotropic transformation contributes to the magnitude of heat treatment deformation. In the third embodiment, 580 Hv was obtained as the surface hardness after quenching, and the surface hardness required for the guide wheel 13 was sufficiently secured. In the second embodiment, a tempering step that requires several hours is not required, and thus there is an advantage that the manufacturing time and the number of steps can be significantly reduced.

FIG. 8 is a table showing a comparison between the above embodiments and the conventional apparatus. The column of the amount of warpage shows the amount of plane distortion after the heat treatment, and the column of the post-processing shows the presence or absence of machining after the heat treatment. In the column of surface hardness, the surface hardness (Vickers hardness) after the heat treatment is shown, and in the column of the rotation condition, the presence or absence of a failure in the rotation condition when the guide wheel 13 is incorporated into the double row spherical roller bearing is shown. It is. As can be seen from FIG. 8, in each of the embodiments of the present invention, the amount of warpage after the heat treatment was 0.1 mm or less, and good rotation was obtained without requiring post-processing. In the conventional apparatus, when the warpage is corrected by the post-processing, a good rotation can be obtained, but when the post-processing is not performed, a problem occurs in the rotation state.

That is, in the conventional apparatus, the guide wheel subjected to the hardening heat treatment has a deformation (warpage) of 0.1 m due to the post-processing.
m, and incorporated into the double-row spherical roller bearing. By adopting the present invention, the guide wheel with a warpage of 0.1 mm or less that does not cause a problem when rotating the double-row spherical roller bearing is provided. It can be manufactured without any processing, and significant advantages can be obtained in terms of manufacturing cost and delivery time.

The description of the specific embodiment is completed above.
The aspect of the present invention is not limited to the above embodiments, and the guide wheels 13 arranged on the outer ring 1 side shown in FIGS.
May be applied. In the case of the double row spherical roller bearing shown in FIG. 5, the retainer 11 is a two-piece press-formed product having a substantially Z-shaped cross-section, and the outer periphery of the guide wheel 13 is provided on the outer periphery as shown in FIG. Parallel cut part 1 for incorporation into
5 are formed. In the first embodiment, the ceramic is used as the material of the straightening type. However, non-magnetic steel, an aluminum alloy, brass, or the like may be used. The quenching or tempering treatment may be performed in a state where the outer peripheral surface or the inner peripheral surface of the ring is restrained. In the second embodiment, a high-pressure gas other than the helium gas may be used, or the pressure may not be set at the illustrated pressure. Also in the third embodiment, the temperature and the quenching time of the molten salt can be changed as appropriate.
In addition, the specific shape of the retainer, the guide wheel, and the like can be appropriately changed depending on design convenience and the like.

[0022]

As is apparent from the above description, according to the first aspect of the present invention, the outer ring having the concave spherical orbit with the center of curvature being the center of the bearing, the inner ring having the two rows of orbits, A double row spherical roller bearing provided with two rows of barrel rollers disposed between the raceways of the inner and outer rings via a vessel and a guide wheel, wherein the guide wheel has an outer peripheral surface and an inner peripheral surface thereof. And, in a state where at least one of the end faces is constrained, quenching or tempering treatment is performed, for example, by performing quenching or tempering treatment in a straightening mold, heat treatment deformation of the guide wheel Below the permissible limit,
No post-processing of the guide wheels is required, and man-hours and manufacturing time can be reduced.

According to the second aspect of the present invention, the outer ring having a concave spherical track whose center is the center of curvature of the bearing, the inner ring having two rows of tracks, the retainer and the guide wheel are used. A double-row spherical roller bearing comprising two rows of barrel rollers disposed between the raceways of the inner and outer rings, wherein the guide wheels are subjected to a quenching treatment in a high-pressure gas atmosphere. Cooling is performed uniformly and quickly compared to oil quenching, etc., heat treatment deformation of the guide wheel due to uneven cooling is kept below the allowable limit, and post-processing of the guide wheel is not required, so man-hours and manufacturing time Can be shortened.

According to the third aspect of the present invention, the outer ring having a concave spherical track whose center is the center of curvature of the bearing, the inner ring having two rows of tracks, the retainer and the guide wheel are used. A double-row spherical roller bearing comprising two rows of barrel rollers disposed between the raceways of the inner and outer rings, wherein the guide wheels are subjected to austempering, so that, for example, they are melted as a quenching refrigerant. By using a salt or the like, the cooling of the work is performed uniformly and quickly as compared with oil quenching and the like, and the transformation of the work becomes bainite transformation which is a diffusion transformation by isothermal transformation using the S curve. As a result, a guide wheel having high toughness and heat treatment deformation less than the allowable limit can be obtained, and post-processing of the guide wheel becomes unnecessary, so that the number of steps and the manufacturing time can be reduced.

[Brief description of the drawings]

FIG. 1 is a half longitudinal sectional view showing a double row spherical roller bearing according to an embodiment.

FIG. 2 is a half cut front view showing a guide wheel in the embodiment.

FIG. 3 is an explanatory diagram showing a tempering step in the embodiment.

FIG. 4 is a graph showing an amount of deformation (warpage) after performing a correction tempering and a normal tempering according to the embodiment.

FIG. 5 is a half vertical sectional view showing another example of a double row spherical roller bearing to which the present invention can be applied.

FIG. 6 is a half-cut front view showing a guide wheel in the example.

FIG. 7 is a graph showing the amount of warpage of the guide wheels due to quenching.

FIG. 8 is a table showing a comparison between each embodiment and a conventional device.

[Explanation of symbols]

 1 outer race 3 raceway 5 inner raceway 7 raceway 9 roller 11 roll press retainer 13 guide wheel 31, 33, 35 correction type 37 high frequency heating coil 39 temperature Total

Claims (3)

[Claims] 1. An outer ring having a concave spherical raceway centered on the center of curvature of a bearing center, an inner ring having two rows of raceways, and a raceway between the inner and outer rings via a retainer and a guide wheel. A double row spherical roller bearing comprising two rows of barrel rollers, wherein the guide wheel is quenched or tempered in a state in which at least one of an outer peripheral surface, an inner peripheral surface, and an end surface is restricted. Double row spherical roller bearing characterized by having been subjected to the following. 2. An outer ring having a concave spherical track whose center of curvature is a bearing center, an inner ring having two rows of tracks, and a track between the inner and outer rings via a retainer and a guide wheel. A double-row spherical roller bearing comprising two rows of barrel rollers, wherein the guide wheel is subjected to a quenching treatment in a high-pressure gas atmosphere. 3. An outer ring having a concave spherical track whose center of curvature is a bearing center, an inner ring having two rows of tracks, and a track between the inner and outer rings via a retainer and a guide wheel. A double row spherical roller bearing comprising two rows of barrel rollers, wherein the guide wheel is subjected to austempering.