WO2011155456A1

WO2011155456A1 - Deep groove ball bearing

Info

Publication number: WO2011155456A1
Application number: PCT/JP2011/062959
Authority: WO
Inventors: 上野　崇
Original assignee: Ntn株式会社
Priority date: 2010-06-11
Filing date: 2011-06-06
Publication date: 2011-12-15
Also published as: JP2011256977A; JP5612912B2

Abstract

Provided is a deep groove ball bearing such that balls can be completely prevented from riding inner and outer race shoulders, and that the rolling fatigue life is long. Balls (31) are installed between a raceway groove (12) of an outer race (11) and a raceway groove (22) of an inner race (21). The balls (31) are retained in a cage (40). A total of four shoulders are formed on both sides of the outer raceway groove (12) and the inner raceway groove (22). As regards these four shoulders, the heights of a pair of shoulders (13a, 23b), which are located diagonally, are set to be higher than those of the remaining pair of shoulders (13b, 23a). The height of the higher shoulder (13a) of the outer race (11) is denoted by H1, the height of the higher shoulder (23b) of the inner race (21) is denoted by H2, and the diameter of the balls (31) is denoted by d. On the basis of these notations, a ratio H1/d, which is the ratio of the shoulder height (H1) of the outer race (11) to the diameter (d) of the balls (31), is set to be within a range of 0.28 - 0.50. Furthermore, a ratio H2/d, which is the ratio of the shoulder height (H2) of the inner race (21) to the diameter (d) of the balls (31), is set to be within a range of 0.37 - 0.50. As a result, the balls (31) are prevented from riding inner and outer race shoulders. Bearing steel which is the raw material for the outer race (11) and the inner race (21), is heat treated, resulting in the rolling fatigue life being improved.

Description

Deep groove ball bearing

This invention relates to a deep groove ball bearing in which a ball is incorporated between an outer ring and an inner ring and the ball is held by a cage.

As shown in FIG. 12, the rotation of the final drive gear 1 of the transmission is transmitted from the final driven gear 2 to the differential case 3 that supports the gear 2, and the rotation of the differential case 3 is transmitted from a pair of pinions 5 fixed to the pinion shaft 4. In the differential that is transmitted to the

side gears

6a, 6b meshing therewith and transmitted to the left and

right axles

7a, 7b that support the

side gears

6a, 6b, the cylindrical portions 8a formed at both ends of the

differential case

3, 8b is rotatably supported by a pair of bearings B supported by the housing 9.

In the above differential, since a helical gear is employed for the final driven gear 2 supported by the differential case 3, when the final driven gear 2 rotates, a thrust load is applied to the differential case 3.

For this reason, it is necessary to use a bearing capable of supporting both a radial load and a thrust load as the bearing B that supports the differential case 3.

In addition, since a helical gear is used to transmit rotational torque in the transmission of an automobile, both radial load and thrust load can be supported as a bearing that supports a shaft provided with the helical gear. It is necessary to use a bearing.

Here, since the tapered roller bearing has a large load capacity and can receive both a thrust load and a radial load, it is suitable for a bearing for supporting the differential case 3 and a bearing for supporting a transmission shaft. In the roller bearing, there is a problem that torque loss is large and fuel consumption is increased. In order to reduce fuel consumption, it is preferable to use a deep groove ball bearing or an angular ball bearing with a small torque loss.

By the way, in the case of a standard deep groove ball bearing, when an excessive thrust load is applied, there is a concern that the ball rides on the shoulder on the load side receiving the thrust load and the shoulder edge is damaged. Also, in the angular ball bearing, when an excessive radial load is applied, there is a concern that the ball rides on the counterbore and has a short life.

In order to eliminate such inconvenience, in the deep groove ball bearing described in Patent Document 1, of the shoulders formed on both sides of the outer ring raceway groove and the inner ring raceway groove, the shoulder on the side receiving the thrust load. Is increased to prevent the ball from climbing and to suppress a decrease in the durability of the bearing.

JP 2000-145795 A

By the way, in the deep groove ball bearing described in the above-mentioned Patent Document 1, nothing is mentioned about the height of the shoulder on the side that prevents the ball from climbing over the shoulder, so the shoulder height is smaller than necessary. There is a problem in the use of the bearing due to the shoulder climbing.

In addition, the deep groove ball bearing has a smaller load capacity than a tapered roller bearing. Therefore, when the rolling fatigue life is requested to be the same as or comparable to that of a tapered roller bearing, a decrease in the rolling fatigue life is a problem. Become.

Furthermore, when used in a transmission, etc., foreign matter such as chips is mixed in the lubricating oil stored in the transmission case. As a result, the outer ring or inner ring raceway groove or the surface of the ball is indented by the foreign matter being caught. Is easily formed, and the damage spreads starting from the indentation, and there is a concern due to early damage.

An object of the present invention is to provide a deep groove ball bearing that can completely prevent a ball from climbing over a shoulder even under a large thrust load and has a long life against rolling fatigue life.

In order to solve the above problems, in the first invention, an outer ring having a raceway groove formed on the inner diameter surface, an inner ring having a raceway groove formed on the outer diameter surface, a raceway groove of the outer ring, and a raceway groove of the inner ring An outer ring raceway groove, out of a total of four shoulders located on both sides of the outer ring raceway groove and the inner ring raceway groove, comprising a ball incorporated in between and a cage formed with a pocket for holding the ball. In the deep groove ball bearing, the height of the shoulder on one side and the shoulder on the other side of the inner ring raceway groove is higher than the height of the shoulder on the other side of the outer ring raceway groove and one side of the inner ring raceway groove. When the height of the shoulder with a high height is H ₁ , the height of the shoulder with a high inner ring height is H ₂ , and the ball diameter of the ball is d, the shoulder height H ₁ of the outer ring with respect to the ball diameter d is The ratio H ₁ / d is in the range of 0.28 to 0.50, and the shoulder of the inner ring with respect to the ball diameter d The ratio H ₂ / d of the height H ₂ is in the range of 0.37 to 0.50, and at least the outer ring and the inner ring among the outer ring, the inner ring and the ball are in a weight ratio of 0.8 to 1.2% carbon. , Formed from an alloy steel containing 0.4 to 1.0% silicon, 0.2 to 1.2% chromium and 0.8 to 1.5% manganese, and after carbonitriding, 830 to 870 ° C. And tempering in the range of 160 to 190 ° C. to make the amount of retained austenite in the surface layer portion 25 to 50%, and the amount of austenite in the core portion to 15 to 120 ° C. 20% was adopted as a structure in which the compressive stress remained in the surface layer portion.

In the deep groove ball bearing having the above configuration, when assembling to a gear support device using a helical gear, a thrust generated by torque transmission to the helical gear is incorporated as an assembly in which the high shoulder of the inner ring is located on the helical gear side. The load should be received by the high shoulders of the outer and inner rings.

At this time, in the shoulder of the outer ring that receives the thrust load, the ratio H ₁ / d of the shoulder height H ₁ to the ball diameter d is 0.28 or more. This is based on the results of the test. In the test, the bearing 6208C was used. Since the ball diameter and the ball PCD of the bearing 6208C are fixed based on the internal specifications, the outer ring shoulder dimension satisfying the outer ring H / d = 0.28 or more is φ65.5 mm. If the shoulder dimension is changed from this shoulder dimension in units of 0.1 mm, shoulder climbing occurs and there is a problem in using the bearing. Therefore, H ₁ / d is set to 0.28 or more.

Further, in the shoulder of the inner ring that receives the thrust load, the ratio H ₂ / d of the shoulder height H ₂ to the ball diameter d is set to 0.37 or more. This is also a rule based on the test results. In the test, the bearing 6208C was used as described above. As described above, since the ball diameter and the ball PCD of the bearing 6208C are fixed based on the internal specifications, the inner ring shoulder dimension satisfying the inner ring H / d = 0.37 is φ56.6 mm. If the shoulder dimension is changed in 0.1 mm increments from this shoulder dimension, shoulder climbing occurs and there is a problem in using the bearing. Therefore, H ₂ / d is set to 0.37 or more.

By specifying the height of the shoulder that receives the thrust load of the outer ring and the height of the shoulder that receives the thrust load of the inner ring as described above, it is possible to completely prevent the ball from riding on the shoulder.

In the deep groove ball bearing according to the first invention, as described above, at least the outer ring and the inner ring are carbonitrided with high carbon bearing steel with a large amount of carbon, quenched from a high temperature, and then tempered at a relatively low temperature. Since the amount of retained austenite in the surface layer portion is 15 to 20%, the rolling fatigue life can be remarkably improved.

In order to solve the above problems, in the second invention, an outer ring having a raceway groove formed on the inner diameter surface, an inner ring having a raceway groove formed on the outer diameter surface, a raceway groove of the outer ring, and a raceway groove of the inner ring An outer ring raceway groove, out of a total of four shoulders located on both sides of the outer ring raceway groove and the inner ring raceway groove, comprising a ball incorporated in between and a cage formed with a pocket for holding the ball. In the deep groove ball bearing, the height of the shoulder on one side and the shoulder on the other side of the inner ring raceway groove is higher than the height of the shoulder on the other side of the outer ring raceway groove and one side of the inner ring raceway groove. When the height of the shoulder with a high height is H ₁ , the height of the shoulder with a high inner ring height is H ₂ , and the ball diameter of the ball is d, the shoulder height H ₁ of the outer ring with respect to the ball diameter d is The ratio H ₁ / d is in the range of 0.28 to 0.50, and the shoulder of the inner ring with respect to the ball diameter d The ratio H ₂ / d of the height H ₂ is in the range of 0.37 to 0.50, and at least the outer ring and the inner ring of the outer ring, the inner ring and the ball are in a weight ratio of 0.6 to 1.2% carbon. silicon 0.15 to 1.1%, formed by chromium 2.0% and bearing steel containing manganese 0.3 to 1.5%, carbonitriding temperature the bearing steel in excess of _{the a 1} transformation point in after carbonitrided, cooled to a temperature below the a ₁ transformation point, then, subjected to quenching and re-heating to a hardening temperature range of 790 ~ 830 ° C., was 8μm below the austenite grain size in average particle size The configuration is adopted.

In the deep groove ball bearing according to the second invention as well, the ratio H ₁ / d of the shoulder height H ₁ of the outer ring to the ball diameter d is set to 0, as in the deep groove ball bearing according to the first invention. And the ratio H ₂ / d of the shoulder height H ₂ of the inner ring to the ball diameter d of the ball is 0.37 or more, so that it is possible to completely prevent the ball from riding on the shoulder.

Further, the outer ring and the inner ring contain 0.6 to 1.2% carbon, 0.15 to 1.1% silicon, 2.0% or less chromium, and 0.3 to 1.5% manganese in terms of weight ratio. formed by bearing steel, again the bearing steel was carbonitrided at a carbonitriding processing temperature in excess of a ₁ transformation point, cooled to a temperature below the a ₁ transformation point, then the quenching temperature range of 790 ~ 830 ° C. By heating and quenching, an austenite crystal grain having an average grain size of 8 μm or less can be obtained, has a long life against rolling fatigue, improves crack strength, and decreases the aging rate. be able to.

In the first and second inventions, when the radius of curvature of the raceway groove of the outer ring is r ₁ , the radius of curvature of the raceway groove of the inner ring is r ₂ , and the ball diameter of the ball is d, the radius d / 2 of the ball The ratio r ₁ / d / 2 of the curvature radius r ₁ of the outer ring raceway groove is in the range of 1.03 to 1.08, and the ratio r ₂ / r of the curvature radius r ₂ of the inner ring raceway groove to the radius d / 2 of the ball When d / 2 is in the range of 1.015 to 1.04, slippage can be prevented at the contact portion between the ball and the raceway groove, and brittle peeling at the contact portion can be prevented.

Further, when the height of the shoulder with the lower height of the outer ring is H ₃ , the height of the shoulder with the lower height of the inner ring is H ₄ , and the ball diameter of the ball is d, the shoulder height of the outer ring with respect to the ball diameter d It is in the range of the ratio _H 3 / d of 0.08 to 0.25 of _{H 3,} and the ratio _H 4 / d of 0.08 to 0.25 of the inner ring shoulder height _{H 4} for the spherical diameter d of the ball If the above-mentioned range is set, the shoulders facing each other in the radial direction of the outer ring and the inner ring should have a larger distance than the case where each of the above shoulders has the same height as that of the standard deep groove ball bearing. Therefore, a cage having a large radial width and a high strength can be adopted as the cage.

Here, the cage includes a cylindrical first divided cage made of a synthetic resin molded product and a synthetic resin cylindrical second divided cage inserted inside the first divided cage. And a notch for forming a circular pocket for holding a ball in a state where both the split cages are combined inside and outside on one axial side surface of the first split cage and the other axial side surface of the second split cage. A connecting means is provided that is spaced apart in the circumferential direction, and in which the first divided holder and the second divided holder form a circular pocket, and the two divided holders are not separated in the axial direction. What consists of composition can be adopted.

Assembling the cage having the above-described configuration is as follows. After the ball is assembled between the outer ring and the inner ring, the first divided cage is formed in the bearing from one side of the outer ring and the inner ring. The second split cage is inserted into the bearing from the other side between the outer ring and the inner ring, and the ball is inserted into the notch formed in the second split cage. Is inserted so that the other side portion in the axial direction of the second split cage is fitted in the one side portion in the axial direction of the first split cage, and both split cages are connected by the connecting means. Link.

As described above, by fitting the second divided cage into the first divided cage, the connecting means are engaged with each other so that the first divided cage and the second divided cage are not separated in the axial direction. Therefore, the deep groove ball bearing can be easily assembled.

In addition, the first split cage and the second split cage having different diameters are asymmetrical combinations in which both end portions are shifted in the axial direction (left-right direction), and the rear end portion in the insertion direction when assembled is the shoulder of the outer ring and the inner ring Therefore, the first split holder and the second split holder can be securely assembled without interfering with the shoulders of the inner and outer rings.

Here, as a connecting means, an inward engagement claw is provided at a tip portion of a pillar portion formed between adjacent notch portions of the first split cage, and between the adjacent notch portions of the second split cage. An outward engaging claw is provided at the tip of the formed column part, and the engaging claw of the first divided holder is engaged with an engaging recess formed on the outer diameter surface of the second divided holder. It is possible to employ a configuration in which the engaging claw of the two-divided cage is engaged with an engaging recess formed on the inner diameter surface of the first divided cage.

In the use of the cage as described above, the cutout portion has a circular shape exceeding a half circle in a planar shape, and has a pair of opposed pocket claws at the opening end, and a spherical shape whose cross-sectional shape follows the outer periphery of the ball It may be formed into a shape, or may be formed into a plane U shape that forms a cylindrical pocket in the fitted state of the first divided holder and the second divided holder.

If a circular shape with a planar shape exceeding one-half circle is used as the notch, the split cage is effectively prevented from falling off by engaging the engaging claw and the engaging recess and engaging the pocket claw and the ball. can do.

On the other hand, by adopting a U-shaped planar shape as the notch, the ball does not interfere with the assembly of the cage, and the cage can be easily incorporated into the bearing.

In adopting a circular notch with a planar shape exceeding a half circle, the circumferential clearance formed between the engaging claw and the engaging recess is larger than the circumferential pocket clearance formed between the ball and the pocket. By doing so, even if a large moment load is applied and the ball is delayed and advanced, the engaging claw will move around the engaging recess even if the first divided holder and the second divided holder rotate relatively. There is no contact with the side surfaces that face each other in the direction, and the effect of preventing damage to the engaging claws can be obtained.

Further, the first split cage and the second split cage can be obtained by setting the axial clearance formed between the engaging claw and the engaging recess larger than the axial pocket clearance formed between the ball and the pocket. When the axial force in the direction separating from each other is applied, the inner surfaces of the pair of opposing pocket claws abut against the outer peripheral surface of the ball, and the engaging claws abut against the axial end surface of the engaging recess. The effect of preventing damage to the engaging claws can be obtained.

On the other hand, in the adoption of a planar U-shaped notch, a circumferential clearance formed between the engaging claw and the engaging recess is accommodated in a pocket formed by two notches that are opposed in the radial direction and in the pocket. By making it larger than the circumferential pocket clearance between the balls, even if a large moment load is applied and the balls are delayed and advanced, the first split cage and the second split cage can rotate relatively. The engaging claws do not come into contact with the side surfaces opposed to each other in the circumferential direction of the engaging recess, and an effect can be obtained in preventing damage to the engaging claws.

Here, since the deep groove ball bearing is lubricated by the lubricating oil, it is preferable that the first split cage and the second split cage are formed of a synthetic resin excellent in oil resistance. Examples of such a resin include polyamide 46 (PA46), polyamide 66 (PA66), and polyphenylene sulfide (PPS). Among these resins, polyphenylene sulfide (PPS) has excellent oil resistance compared to other resins, and therefore, considering the oil resistance, it is most preferable to use polyphenylene sulfide (PPS).

In consideration of the price of the resin material, it is preferable to use polyamide 66 (PA66), which may be determined appropriately according to the type of the lubricating oil.

Note that the cage is not limited to the one having the above-described configuration, for example, a cage that is divided into two in the axial direction. Each of the cages has a plurality of hemispherical pocket portions and a width of the pocket portion. A plurality of coupling plate portions having the same width as the dimensions are continuously waved in the circumferential direction, the outer diameters of the coupling plate portions of the two waveform split cages are the same, and one waveform The position of the pocket part of the split cage is shifted to the inner diameter side with respect to the coupling plate part, and the position of the pocket part of the other waveform split cage is shifted to the outer diameter side with respect to the coupling plate part. And insert the other corrugated cage into the bearing from the lower shoulder side of the outer ring to the inside of the bearing. It may consist of the structure which provided.

As described above, both the first invention and the second invention can completely prevent the balls from climbing over the shoulder even when subjected to a large thrust load, and have a long life against rolling fatigue life. A deep groove ball bearing can be obtained. For this reason, it can be incorporated into a bearing device where a tapered roller bearing is required, and the incorporation into the bearing device can reduce torque loss and achieve low fuel consumption.

Further, in the deep groove ball bearing according to the first invention, the outer ring and the inner ring are formed of high carbon bearing steel with a large amount of carbon, and after carbonitriding the high carbon bearing steel and quenching from high temperature, By tempering at a low temperature, the amount of retained austenite in the surface layer portion is 15 to 20%, so that the rolling fatigue life can be remarkably improved.

Further, in the deep groove ball bearing according to the second invention, to form a outer ring and the inner ring carbon intensive bearing steel, after the bearing steel was carbonitrided at a carbonitriding processing temperature above the A ₁ transformation point, cooled to a temperature below the a ₁ transformation point, then, by a heat treatment of performing quenching and re-heating in the quenching temperature range of 790 ~ 830 ° C., to form the austenite crystal grains of 8μm following microstructure with an average grain size Therefore, it is possible to obtain a deep groove ball bearing that has a long life against rolling fatigue, an improved crack strength, and a low durability with a low rate of aging.

Longitudinal front view showing an embodiment of a deep groove ball bearing according to the present invention The right view which shows a part of cage | basket shown in FIG. The left view which shows a part of cage shown in FIG. Sectional drawing which expands and shows the coupling | bond part of the 1st division | segmentation holder | retainer of FIG. 1, and a 2nd division | segmentation holder | retainer The top view which shows a part of a 1st division | segmentation holder | retainer and a 2nd division | segmentation holder | retainer (I) is a plan view showing a pocket clearance in the circumferential direction in a state where a ball is incorporated in the pocket of the first split cage shown in FIG. 5, and (II) is a plan view of the first split cage shown in FIG. Top view showing the pocket clearance in the axial direction with the ball in the pocket Partial plan view showing another example of a synthetic resin cage The top view which shows the pocket clearance of the circumferential direction in the state which built the ball | bowl in the pocket of the 1st division | segmentation holder | retainer shown in FIG. Sectional drawing which shows the other example of the outer ring raceway groove and the inner ring raceway groove The top view of the part which shows the further another example of a holder | retainer The top view of the part which shows the further another example of a holder | retainer Cross-sectional view showing differential

Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, in the deep groove ball bearing A, a ball 31 is incorporated between a raceway groove 12 formed on the inner diameter surface of the outer ring 11 and a raceway groove 22 provided on the outer diameter surface of the inner ring 21. Is held by the cage 40.

Of the pair of

shoulders

13a, 13b formed on both sides of the raceway groove 12 of the outer ring 11, the height of the shoulder 13a located on one side of the raceway groove 12 is higher than the shoulder 13b located on the other side. Yes. On the other hand, of the pair of

shoulders

23a and 23b formed on both sides of the raceway groove 22 of the inner ring 21, the height of the shoulder 23b located on the other side of the raceway groove 22 is higher than the height of the shoulder 23a located on one side. It is high.

For convenience of explanation, the

high shoulders

13a and 23b are referred to as thrust

load side shoulders

13a and 23b, and the

low shoulders

13b and 23a are referred to as thrust non-load side shoulders 13b and 23a.

When the height of the shoulder 13a on the thrust load side of the outer ring 11 is H ₁ , the height of the shoulder 23b on the thrust load side of the inner ring 21 is H ₂ , and the ball diameter of the ball 31 is d, the ball diameter d of the ball 31 The ratio H ₁ / d of the shoulder height H ₁ of the outer ring 11 is in the range of 0.28 to 0.50, while the ratio of the shoulder height H ₂ of the inner ring 21 to the ball diameter d of the ball 31 is H ₂ / d is in the range of 0.37 to 0.50.

The height H ₃ of the shoulder 13b on the thrust non-load side of the outer ring 11 and the height H ₄ of the shoulder 23a on the thrust non-load side of the inner ring 21 are the same as the shoulder height of the standard deep groove ball bearing. . The standard deep groove ball bearing is a bearing in which the height of the pair of shoulders of the outer ring and the height of the pair of shoulders of the inner ring are the same.

The outer ring 11 and the inner ring 21 are, by weight ratio, carbon (C) 0.8 to 1.2%, silicon (Si) 0.4 to 1.0%, chromium (Cr) 0.2 to 1.2%. And a heat-treated product made of a high carbon bearing steel containing 0.8 to 1.5% of manganese (Mn).

In the heat treatment, after carbonitriding, quenching is performed from 830 to 870 ° C. to obtain a quenching termination temperature of 90 to 120 ° C., and then tempering in the range of 160 to 190 ° C. Is 25 to 50%, and the austenite content of the core is 15 to 20%.

Here, the reason why the composition of the above-mentioned high carbon bearing steel is set to a high carbon of C 0.8 to 1.2% is that the surface layer portion is basically hardened by quenching and tempering. If Cr is less than 0.2%, carbide is not formed if the Cr is less than 0.2%, and the hardness of the surface layer is insufficient. If it exceeds 1.2%, the carbide becomes coarse and becomes a starting point of peeling. This is because the life is likely to be short.

Si stably increases the retained austenite of the surface layer to 25% or more, imparts temper softening resistance, and secures heat resistance, but 0.4% or more is necessary, but if Si exceeds 1% This is because, during the carbonitriding process, the enrichment of nitrogen and carbon from the skin to the surface layer is inhibited.

Mn is for securing the hardenability and quenching to the core, but increases the retained austenite in the surface layer with an element that stabilizes the retained austenite in the quenching and tempering processes. Addition of a large amount of Mn causes a decrease in cold workability and causes cracking and embrittlement, and therefore increases to a range not exceeding 1.5% Mn.

SUJ3 steel can be used as such a high carbon bearing steel. Mo is appropriately added to 0.3% for improving hardenability. SUJ5 steel is used as a material to which Mo is added.

When the outer ring 11 and the inner ring 21 are formed of the high carbon bearing steel having such a composition and carbonitrided, the nitrogen content of the surface layer portion becomes high, and the Ms point of the surface layer portion decreases as compared with the core portion. Then, untransformed austenite is increased in the surface layer portion than in the core portion. Since nitrogen is high in the surface layer portion and the quenching start temperature (austenitizing temperature) is increased to 830 to 870 ° C., the retained austenite in the surface layer portion can be easily increased to 25% or more. In order to stably increase the retained austenite, the quenching end temperature is increased to about 100 ° C., preferably 90 to 120 ° C. In this quenching process, the martensitic transformation of the surface portion enriched with nitrogen starts later than the inside, and the amount of transformation is less than the inside, so that residual compressive stress is formed in the surface portion.

Since the quenching start temperature (austenitizing temperature) is 830 to 870 ° C., which is higher than that of ordinary quenching and tempering steel, the crack sensitivity value associated with quenching increases. Therefore, it is preferable to control the cooling rate in the martensitic transformation process by setting the cooling capacity H in the range of 300 to 150 ° C. in the quenching process to 0.2 cm −1 or less.

In the carbonitriding process, carbonitriding is usually performed in a high-temperature gas in which ammonia is added to a carburizing or reducing gas. In this case, the above conditions are immediately applied after carbonitriding in a temperature range of 830 to 870 ° C. Quench in oil.

In the above heat treatment, the tempering temperature after quenching is set to a relatively low temperature of 160 to 190 ° C., and the retained austenite in the surface layer portion is set to a range of 25 to 50% by suppressing decomposition of the retained austenite in the tempering process. The higher the retained austenite in this range, the rolling fatigue life is improved under the lubrication conditions under the presence of foreign matter. On the other hand, the surface hardness is lowered and the wear resistance is lowered. A range of 25 to 30% is preferable. On the other hand, since the core portion is tempered at a low temperature of 190 ° C. or lower, usually about 15 to 20% of retained austenite remains.

In the embodiment, only the outer ring 11 and the inner ring 21 are heat-treated, but the ball 31 may be a heat-treated product similar to the outer ring 11 and the inner ring 21.

As shown in FIG. 1 to FIG. 3, the holder 40 includes a first divided holder 41 and a second divided holder 42 inserted inside the first divided holder 41.

As shown in FIG. 5, the first split holder 41 has a pair of opposed pocket claws 44 formed on the one side surface in the axial direction of the annular body 43 at equal intervals in the circumferential direction. The planar shape of the annular body 43 is made of a synthetic resin molded product provided with a notch 45 having a size exceeding a half circle.

Here, as shown in FIG. 1, the inner diameter of the annular body 43 is substantially equal to the pitch circle diameter (PCD) of the balls 31, and the outer diameter is equal to the inner diameter of the shoulder 13a where the height of the outer ring 11 is high and the shoulder whose height is low. The inner diameter of the outer ring 11 can be inserted into the bearing from the lower shoulder 13b side. Further, the inner surface of the notch 45 is a spherical shape along the outer periphery of the ball 31.

On the other hand, the first split holder 41 has a pair of opposed pocket claws 49 formed on the other side surface in the axial direction of the annular body 48 at equal intervals in the circumferential direction, and the annular body 48 is wound between each pair of opposed pocket claws 49. It consists of a molded product of synthetic resin provided with a cutout portion 50 having a size that exceeds a half of a half of the planar shape to be extracted.

As shown in FIG. 1, the outer diameter of the annular body 48 is substantially equal to the pitch circle diameter (PCD) of the balls 31, and the inner diameter is the outer diameter of the high shoulder 23b of the inner ring 21 and the low shoulder 23a. The outer diameter is within the range. The second split cage 42 can be inserted into the bearing from the low shoulder 23a side, and can be fitted inside the first split cage 41. Further, the inner surface of the notch 50 is formed in a spherical shape along the outer periphery of the ball 31.

As shown in FIG. 4 and FIG. 5, the shaft of the second split holder 42 is located between the first split holder 41 and the second split holder 42 within one side in the axial direction of the first split holder 41. In a state where a circular pocket is formed by a pair of

opposed notches

45 and 50 by inserting the other side portion in the direction, the first split holder 41 and the second split holder 42 are non-separated in the axial direction. Means X are provided.

The connecting means X is provided with an inward engagement claw 46 at the tip of a pillar portion 43a formed between adjacent cutout portions 45 of the first split holder 41, and the engagement member X is provided on the inner diameter surface of the annular body 43. A groove-like engagement recess 47 is formed on the same axis as the joint claw 46, and an outward engagement claw 51 is formed at the tip of a column part 48 a formed between the adjacent notches 50 of the second split holder 42. And an engagement recess 52 is formed on the outer diameter surface of the annular body 48 on the same axis as the engagement claw 51, and the engagement claw 46 of the first divided holder 41 and the second divided holder 42 are By the engagement of the engagement recess 52 and the engagement of the engagement claw 51 of the second split retainer 42 and the engagement recess 47 of the first split retainer 41, the first split retainer 41 and the second split retainer. 42 is not separated in the axial direction.

Here, since the first split cage 41 and the second split cage 42 come into contact with the lubricating oil that lubricates the deep groove ball bearing, a synthetic resin excellent in oil resistance is used. Examples of such a synthetic resin include polyamide 46 (PA46), polyamide 66 (PA66), and polyphenylene sulfide (PPS). These resins may be selected and used according to the type of lubricating oil.

The deep groove ball bearing shown in the embodiment has the above-described structure. When the deep groove ball bearing is assembled, the inner ring 21 is inserted inside the outer ring 11, the race groove 22 of the inner ring 21 and the race groove of the outer ring 11. A required number of balls 31 are assembled between 12.

At this time, the inner ring 21 is offset in the radial direction with respect to the outer ring 11, a part of the outer diameter surface of the inner ring 21 is brought into contact with a part of the inner diameter surface of the outer ring 11, and 180 degrees in the circumferential direction from the contact part. A crescent-shaped space is formed at a shifted position, and the ball 31 is assembled from one side of the space.

Upon incorporation of the balls 31, when the shoulder height H ₁ of the thrust load side shoulder 13a and the height of the inner ring 21 of the outer ring 11 is high shoulder 23b is higher than necessary, to inhibit the incorporation of the balls 31 However, in the embodiment, the ratio H ₁ / d of the outer ring shoulder height H _{1 to} the ball diameter d of the ball 31 and the ratio H ₂ / d of the inner ring shoulder height H ₂ do not exceed 0.50. Because of the height, the ball 31 can be reliably assembled between the outer ring 11 and the inner ring 21.

After the ball 31 is assembled, the center of the inner ring 21 is made to coincide with the center of the outer ring 11, the balls 31 are arranged at equal intervals in the circumferential direction, and the outer ring 11 and the inner ring 21 from one side of the shoulder 13b where the height of the outer ring 11 is low. The first split holder 41 is inserted between the notches 45 formed in the first split holder 41 so that the balls 31 are fitted therebetween.

Further, the second split retainer 42 is inserted between the outer ring 11 and the inner ring 21 from one side of the shoulder 23a where the height of the inner ring 21 is low, and the ball 31 is inserted into the notch 50 formed in the second split retainer 42. It inserts so that it may fit, and the axial direction other side part of the 2nd division | segmentation holder | retainer 42 is fitted in the axial direction one side part of the 1st division | segmentation holder | retainer 41. FIG.

As described above, the engagement claws formed in the respective divided

holders

41 and 42 by fitting the second divided holder 42 into the first divided holder 41 as shown in FIGS. 46 and 51 are engaged with

engaging recesses

47 and 52 provided in the other split cage, and the assembly of the deep groove ball bearing is completed.

Thus, after the ball 31 is assembled between the raceway groove 12 of the outer ring 11 and the raceway groove 22 of the inner ring 21, the first divided holder 41 and the second divided hold are internally provided from both sides between the outer ring 11 and the inner ring 21. The deep groove ball bearing A can be assembled by a simple operation of inserting the container 42 and fitting the second divided holder 42 into the first divided holder 41.

When the above-described deep groove ball bearing A is used to support the

cylindrical portions

8a and 8b formed at both ends of the differential case 3 shown in FIG. 12, the deep groove ball bearing A has a load driven shoulder 23b of the inner ring 21 with a final driven gear. Assembled on the 2nd side.

When the differential case 3 rotates in the forward traveling direction of the vehicle by torque transmission from the final drive gear 1 in the assembled state, a thrust force is applied to the differential case 3 by the rotation of the final driven gear 2 formed of a helical gear, and the thrust force is 12 is supported by the thrust load side shoulder 23b of the inner ring 21 and the thrust load side shoulder 13a of the outer ring 11 of the deep groove ball bearing A that receives the left end of the differential case 3 of FIG.

At this time, a thrust force is also applied to the ball 31, and when the thrust load side shoulder 23b of the inner ring 21 and the thrust load side shoulder 13a of the outer ring 11 are lower than necessary, the ball 31 rides on the

shoulders

13a, 23b, There is a possibility of damaging the edges of the

shoulders

13a and 23b.

However, in the embodiment, the ratio H ₁ / d of the shoulder load H ₁ on the thrust load side of the outer ring 11 to the ball diameter d of the ball 31 is in the range of 0.28 to 0.50, and the ball diameter of the ball Since the ratio H ₂ / d of the shoulder height H ₂ on the thrust load side of the inner ring 21 to d is in the range of 0.37 to 0.50, it is possible to reliably prevent the ball 31 from climbing.

For comparison, a standard deep groove ball bearing 6208C having an inner ring outer diameter of φ53.1 mm and an outer ring inner diameter of φ68.1 mm is used as a comparative product, and the thrust load side of the inner ring is based on the standard deep groove ball bearing. A deep groove ball bearing in which the outer diameter of the shoulder of the outer ring is changed from φ53.1 mm to φ56.6 mm and the inner diameter of the shoulder on the thrust load side of the outer ring is changed from φ68.1 mm to φ65.5 mm. When the allowable thrust load was measured, the deep groove ball bearing of the present invention showed a value higher by 305% than the comparative deep groove ball bearing. In addition, the outer diameter of the shoulder of the inner ring where the thrust load (axial load) is not applied is changed from the standard φ53.1 mm to φ51.9 mm, and the inner diameter of the shoulder of the outer ring where the axial load is not applied is changed to the standard Even when the diameter was changed from φ68.1 mm to φ70.4 mm, even when the basic statically constant load Co was applied to the bearing, no shoulder climbing occurred.

When the differential case 3 rotates in the backward running direction of the vehicle, the thrust force applied to the differential case 3 is the shoulder on the thrust load side of the inner ring 21 of the deep groove ball bearing A that receives the right end of the differential case 3 in FIG. 23b and a thrust load side shoulder 13a of the outer ring 11. Also in this case, it is possible to reliably prevent the ball 31 from climbing.

In the deep groove ball bearing according to the embodiment, the outer ring 11 and the inner ring 21 are made of high carbon bearing steel with a large amount of carbon, the high carbon bearing steel is carbonitrided, quenched from a high temperature, and then tempered at a relatively low temperature. Since the amount of retained austenite in the surface layer is 15 to 20%, the fatigue strength of the raceway surface on which the balls 31 of the outer /

inner rings

11 and 21 roll and move is extremely high, and the raceway surface is damaged. There is no.

Here, when the outer ring 11 and the inner ring 21 rotate relative to each other, the ball 31 revolves while rotating, and the cage 40 also rotates due to the revolution, and when lubricating oil is interposed between the outer ring 11 and the inner ring 21, Lubricating oil will be rotated by contact with the cage 40.

At this time, since the first split cage 41 and the second split cage 42 have different outer diameters, there is a difference in peripheral speed, and the flow of lubricating oil that is rotated by contact with the first split cage 41 is the first. It becomes faster than the flow of the lubricating oil driven by the contact with the two-divided cage 42, the lubricating oil on the slow flow side is attracted to the fast flow side, and a pump action is generated inside the bearing. Due to the pump action, the lubricating oil flows in the direction indicated by the arrow in FIG. 1 and the inside of the bearing is forcibly lubricated, so that the lubricity of the deep groove ball bearing A can be improved.

In the deep groove ball bearing shown in the embodiment, a pair of

opposed pocket claws

44 and 49 that embed the ball 31 in the open ends of the cutout portion 45 of the first divided holder 41 and the cutout portion 50 of the second divided holder 42. And a pair of opposed pocket claws 44 formed in the first divided holder 41 and a pair of opposed pocket claws 49 provided in the second divided holder 42 are oriented in opposite directions, and in the combined state Since the

engagement claws

46 and 51 are engaged with the engagement recesses 47 and 52 and the first divided holder 41 and the second divided holder 42 are not separated in the axial direction, a large moment load is applied. Even if the ball 31 is delayed or advanced, the retainer 40 does not fall off.

Here, as shown in FIG. 6 (I), the clearance δ ₁ of the circumferential clearance 60 formed between the engaging

claws

46, 51 and the engaging

recesses

47, 52 is set between the ball 31 and the

notches

45, 50. By making the clearance larger than the clearance amount δ _{2 of the} circumferential pocket clearance 61 formed on the ball 31, a large moment load is applied and the ball 31 is delayed and advanced, and the first split retainer 41 and the second split retainer 42, the engaging

claws

46 and 51 do not come into contact with the opposite side surfaces of the engaging

recesses

47 and 52 in the circumferential direction, which is effective in preventing damage to the engaging

claws

46 and 51. Can be mentioned.

Further, as shown in FIG. 6 (II), the clearance δ ₃ of the axial clearance 62 formed between the engaging

claws

46, 51 and the engaging

recesses

47, 52 is set between the ball 31 and the

notches

45, 50. When the axial force in the direction away from the first divided cage 41 and the second divided cage 42 is applied to the first divided cage 41 and the second divided cage 42 by making the gap amount δ _{4 of the} formed axial pocket gap 63 larger than the gap amount δ _4. The inner surfaces of the pair of

pocket claws

44 and 49 abut against the outer peripheral surface of the ball 31, and the

engagement claws

46 and 51 do not abut against the axial end surfaces of the engagement recesses 47 and 52. The effect of preventing the damage of 46 and 51 can be obtained.

In FIGS. 1 and 5, as the

notches

45 and 50, the planar shape of the

annular bodies

43 and 48 is larger than a half circle, and the cross-sectional shape is an arc shape. However, the

notches

45 and 50 are not limited to this. For example, as shown in FIG. 7, a flat U-shape that forms a cylindrical pocket in the fitted state of the first divided holder 41 and the second divided holder 42 may be used.

When the

notches

45 and 50 shown in FIG. 7 are employed, the clearance δ _{5 of the} circumferential clearance 64 formed between the engaging

claws

46 and 51 and the engaging

recesses

47 and 52 as shown in FIGS. Is larger than the clearance amount δ _{6 of the} circumferential pocket clearance 66 formed between the ball 31 and the

notches

45 and 50, a large moment load is applied and the ball 31 is delayed and advanced. Even if the split holder 41 and the second split holder 42 are relatively rotated, the engaging

claws

46 and 51 do not come into contact with the side surfaces of the engaging

recesses

47 and 52 that are opposed to each other in the circumferential direction. An effect can be obtained in preventing damage to the

claws

46 and 51.

In the embodiment, the weight ratio of the outer ring 11 and the inner ring 21 is 0.8 to 1.2% for carbon, 0.4 to 1.0% for silicon, 0.2 to 1.2% for chromium, and 0. Formed with high carbon bearing steel containing 8 to 1.5%, carbonitrided, and then quenched from 830 to 870 ° C to a quenching end temperature of 90 to 120 ° C, then in the range of 160 to 190 ° C The outer austenite 11 and the inner ring are made to remain in the surface layer by setting the austenite amount in the surface layer to 25 to 50% and the austenite amount in the core portion to 15 to 20%. The forming material and heat treatment of 21 are not limited to this.

For example, the weight ratio of the outer ring 11 and the inner ring 21 is 0.6 to 1.2% carbon, 0.15 to 1.1% silicon, 2.0% or less chromium, and 0.3 to 1.5% manganese. formed by a bearing steel containing, after the bearing steel was carbonitrided at a carbonitriding processing temperature above the a ₁ transformation point, cooled to a temperature below the a ₁ transformation point, then quenching temperature region of 790 ~ 830 ° C. You may make it quench by reheating to.

Here, if the carbon content exceeds 1.2% by weight, the material hardness is high even if spheroidizing annealing is performed, so that the cold workability is hindered, and the amount of cold work sufficient when performing cold work, The accuracy cannot be obtained. In addition, the carbonitriding process tends to become an excessively carburized structure, and there is a risk that the cracking strength is reduced. On the other hand, when the carbon content is less than 0.6% by weight, it takes a long time to secure the required surface hardness and the amount of retained austenite, or the necessary internal hardness is obtained by quenching after reheating. It becomes difficult to be.

The reason why the Si content is 0.15 to 1.1% by weight is that Si increases resistance to tempering softening to ensure heat resistance and improves rolling fatigue life characteristics under lubrication with foreign matter. It is. If the silicon content is less than 0.15% by weight, the rolling fatigue life characteristics under lubrication with foreign matter will not be improved. On the other hand, if it exceeds 1.1% by weight, the hardness after normalization will be too high and cold working will occur. Inhibits sex.

Mn is effective in securing the quench hardening ability of the carbonitrided layer and the core. If the Mn content is less than 0.3% by weight, sufficient quenching and hardening ability cannot be obtained, and sufficient strength cannot be secured in the core. On the other hand, if the Mn content exceeds 1.5% by weight, the curing ability becomes excessively high, the hardness after normalization becomes high, and cold workability is hindered. In addition, the austenite is excessively stabilized and the amount of retained austenite in the core is excessively increased to promote a change in size over time.

The bearing steel may contain 2.0% by weight or less of chromium. By including 2.0% by weight or less of chromium, chromium carbide and nitride are precipitated in the surface layer portion, and the hardness of the surface layer portion is easily improved. The Cr content is set to 2.0% by weight or less. If it exceeds 2.0% by weight, the cold workability is remarkably lowered, or even if the content exceeds 2.0% by weight, the hardness of the surface layer portion described above This is because the improvement effect is small.

As described above, carbon 0.6 to 1.2%, silicon from 0.15 to 1.1%, chromium 2.0% and a bearing steel containing manganese 0.3 ~ 1.5% _{A 1} transformation after carbonitriding at carbonitriding temperature exceeding the point, cooled to a temperature below the a ₁ transformation point, then, by performing quenching and re-heating in the quenching temperature range of 790 ~ 830 ° C., an average particle diameter An austenite crystal grain having a microstructure of 8 μm or less can be obtained, has a long life against rolling fatigue, can improve the cracking strength, and can reduce the aging rate.

In FIG. 1, the height H ₃ of the shoulder 13 b on the thrust non-load side of the outer ring 11 and the height H ₄ of the shoulder 23 a on the thrust non-load side of the inner ring 21 are the same as the shoulder of the standard deep groove ball bearing. However, it may be lower than the shoulder height of the standard deep groove ball bearing.

When the height of the

shoulders

13b and 23a on the thrust non-load side is made lower than the height of the shoulder of the standard deep groove ball bearing, the radial widths of the first waveform segmented cage 41 and the second waveform segmented cage 42 are reduced accordingly. Since W can be increased, the strength of the cage 40 can be increased.

Here, the lower than necessary height of thrust non-load side of the

shoulder

13b and 23a, because the run-up of the ball 31 may occur, for the height H ₃ of the shoulder 13b of the outer ring 11, the ball 31 The ratio H ₃ / d of the shoulder height H ₃ to the sphere diameter d is set in the range of 0.08 to 0.25.

For the shoulder 23 a of the inner ring 21, the ratio H ₄ / d of the shoulder height H ₄ to the ball diameter d of the ball 31 is in the range of 0.08 to 0.25.

In the deep groove ball bearing A, when the outer ring 11 and the inner ring 21 rotate relatively, the ball 31 rolls along the outer ring raceway groove 12 and the inner ring raceway groove 22. In this case, when the radius of curvature r ₂ of the curvature radius r ₁ and the inner ring raceway groove 22 of the outer ring raceway groove 12 shown in FIG. 9 becomes smaller than necessary, slip occurs between the balls 31, is brittle flaking in contact portion If it occurs and becomes larger than necessary, the calculated value of the rated load will decrease.

Therefore, the ratio r ₁ / d / 2 of the radius of curvature r ₁ of the outer ring raceway groove 12 to the radius d / 2 of the ball 31 is set in the range of 1.03 to 1.08, and the inner ring with respect to the radius d / 2 of the ball 31 is set. The ratio r ₂ / d / 2 of the radius of curvature r ₂ of the raceway groove 22 should be in the range of 1.015 to 1.04 to prevent brittle peeling and suppress the decrease in the calculated load value.

10 and 11 show another example of the cage 40. FIG. The holder 40 shown in FIG. 10 includes split

holders

71 and 72 that are divided into two in the axial direction. Each of the

split holders

71 and 72 includes a plurality of hemispherical pocket portions 73 and pocket portions 73. A plurality of coupling plate parts 74 having the same width dimension as the width dimension are alternately and continuously corrugated in the circumferential direction, and the outer diameters of the coupling plate parts 74 of the two

waveform division holders

71 and 72 are the same. The position of the pocket portion 73 of one waveform division holder 71 is shifted to the inner diameter side with respect to the coupling plate portion 74, and the pocket portion 73 of the other waveform division holder 72 is outer diameter with respect to the coupling plate portion 74. The one waveform segmented retainer 71 is inserted into the bearing from the side of the shoulder 13a having the higher height of the outer ring 11, and the other waveform segmented retainer 72 is lowered in the height of the outer ring 11. Insert into the bearing from the shoulder 13b side, The pocket 75 is provided between the parts 73, and the two coupling plates 74 which abut each other so as to bind with rivets 76.

Here, the cage 40 may be made of a metal plate press-molded product, or may be made of a synthetic resin molded product.

In the cage 40 having the above-described configuration, after the ball 31 is assembled between the outer ring 11 and the inner ring 21, one side between the outer ring 11 and the inner ring 21 is formed from one side of the shoulder 23 a on the thrust non-load side of the inner ring 21. The waveform division holder 71 is inserted so that the ball 31 fits into the pocket portion 73 formed in the waveform division holder 71.

Further, the other waveform division holder 72 is provided between the outer ring 11 and the inner ring 21 from one side of the shoulder 13 b on the thrust non-load side of the outer ring 11, and the ball 31 is inserted into a pocket portion 73 formed in the waveform division holder 72. Is inserted so that the coupling plate portion 74 of one waveform division holder 71 and the coupling plate portion 74 of the other waveform division holder 72 are brought into contact with each other, and the two coupling plate portions 74 are rivets. It joins by crimping 76.

In the assembled state of the deep groove ball bearing as described above, the pocket portion 73 of one of the wave split cages 71 faces the shoulder 13a on the thrust load side of the outer ring 11 in the radial direction, and the pocket portion 73 is the coupling plate portion 74. Therefore, a gap is formed between the outer ring 11 and the shoulder 13a on the thrust load side.

Further, the pocket portion 73 of the other waveform division holder 72 is opposed to the thrust load side shoulder 23b of the inner ring 21 in the radial direction, and the pocket portion 73 is displaced radially outward with respect to the coupling plate portion 74. Thus, a gap is formed between the inner ring 21 and the shoulder 23b on the thrust load side.

For this reason, when the deep groove ball bearing rotates, the pocket portion 73 of the cage 40 does not interfere with the thrust

load side shoulders

13a and 23b, and the outer ring 11 and the inner ring 21 can be smoothly rotated relative to each other. .

In the cage 40 shown in FIG. 11, a ball non-contact portion 77 made of a concave portion is provided on the inner peripheral surface of the pocket 75 of each of the pocket portions 73 of the

waveform division holders

71 and 72 shown in FIG. The contact area with the ball 31 is 15% to 30% lower than the contact area with the ball 31 when the ball non-contact portion 77 is not provided.

As described above, by providing the ball non-contact portion 77 formed of a recess on the inner peripheral surface of the pocket 75 of the pocket portion 73, the resistance when the lubricant passes through the pocket 75 and the amount of oil film to be sheared are reduced. Can be achieved, and a great effect can be obtained in reducing torque loss.

11 outer ring 12 raceway groove 13a shoulder 13b shoulder 21 inner ring 22 raceway groove 23a shoulder 23b shoulder 31 ball 40 retainer 41 first divided retainer 42 second divided retainer 43a pillar 44 pocket claw 45 notch 46 engagement claw 47 Joint recess 48a Column 49 Pocket claw 50 Notch 51 Engagement claw 52 Engagement recess 60 Circumferential clearance 61 Circumferential pocket clearance 62 Axial clearance 63 Axial pocket clearance 64 Circumferential clearance 65 Circumferential pocket clearance X Connecting means 71 Waveform division holder 72 Waveform division holder 73 Pocket portion 74 Connecting plate portion 75 Pocket

Claims

An outer ring having a raceway groove formed on the inner diameter surface, an inner ring having a raceway groove formed on the outer diameter surface, a ball assembled between the raceway groove of the outer ring and the raceway groove of the inner ring, and a pocket for holding the ball are formed. Among the total of four shoulders located on both sides of the outer ring raceway groove and the inner ring raceway groove, the height of the shoulder on one side of the outer ring raceway groove and the shoulder on the other side of the inner ring raceway groove In a deep groove ball bearing in which the height is higher than the shoulder on the other side of the outer ring raceway groove and the shoulder on one side of the inner ring raceway groove,
The shoulder height of the outer ring with respect to the ball diameter d, where H 1 is the height of the high shoulder of the outer ring, H 2 is the height of the shoulder of the inner ring, and d is the ball diameter of the ball. the ratio H 1 / d of an H 1 in the range of 0.28 to 0.50, and the inner ring relative to spherical diameter d of the ball shoulder height H 2 ratio H 2 / d of 0.37 to 0.50 The outer ring, the inner ring, and the ball, and at least the outer ring and the inner ring are in a weight ratio of carbon 0.8 to 1.2%, silicon 0.4 to 1.0%, chromium 0.2 to 1.2. % And manganese containing 0.8 to 1.5%, and carbonitriding, followed by quenching from 830 to 870 ° C. to a quenching end temperature of 90 to 120 ° C., then 160 to 190 Tempering in the range of ° C. to make the amount of retained austenite in the surface layer part 25 to 50%, and the core As the austenite amount 15-20%, deep groove ball bearing, characterized in that leaving a compressive stress in the surface portion.
An outer ring having a raceway groove formed on the inner diameter surface, an inner ring having a raceway groove formed on the outer diameter surface, a ball assembled between the raceway groove of the outer ring and the raceway groove of the inner ring, and a pocket for holding the ball are formed. Among the total of four shoulders located on both sides of the outer ring raceway groove and the inner ring raceway groove, the height of the shoulder on one side of the outer ring raceway groove and the shoulder on the other side of the inner ring raceway groove In a deep groove ball bearing in which the height is higher than the shoulder on the other side of the outer ring raceway groove and the shoulder on one side of the inner ring raceway groove,
The shoulder height of the outer ring with respect to the ball diameter d, where H 1 is the height of the high shoulder of the outer ring, H 2 is the height of the shoulder of the inner ring, and d is the ball diameter of the ball. the ratio H 1 / d of an H 1 in the range of 0.28 to 0.50, and the inner ring relative to spherical diameter d of the ball shoulder height H 2 ratio H 2 / d of 0.37 to 0.50 The outer ring, the inner ring and the ball, and at least the outer ring and the inner ring are in a weight ratio of carbon 0.6 to 1.2%, silicon 0.15 to 1.1%, chromium 2.0% or less, and manganese. 0.3 is formed by a bearing steel containing ~ 1.5%, the bearing steel was carbonitrided at a carbonitriding processing temperature in excess of a 1 transformation point, cooled to a temperature below the a 1 transformation point, then , Reheat to a quenching temperature range of 790 to 830 ° C. and quench, and change the austenite grain size Deep groove ball bearing, characterized in that the 8μm or less Hitoshitsubu diameter.
The deep groove ball bearing according to claim 2, wherein the bearing steel contains 2.0% by weight or less of chromium.
When the height of the lower shoulder of the outer ring is H 3 , the height of the lower shoulder of the inner ring is H 4 , and the ball diameter of the ball is d, the shoulder height of the outer ring with respect to the ball diameter d of the ball the ratio H 3 / d of H 3 in the range 0.08 to 0.25 and of the inner ring relative to spherical diameter d of the ball shoulder height H 4 ratio H 4 / d of 0.08 to 0.25 The deep groove ball bearing according to any one of claims 1 to 3, wherein the bearing is a range.
The ratio of the radius of curvature r 1 of the outer ring raceway groove to the radius d / 2 of the ball, where r 1 is the radius of curvature of the raceway groove of the outer ring, r 2 is the radius of curvature of the raceway groove of the inner ring, and d is the ball diameter of the ball. r 1 / d / 2 is in the range of 1.03 to 1.08, and the ratio r 2 / d / 2 of the curvature radius r 2 of the inner ring raceway groove to the radius d / 2 of the ball is 1.015 to 1.2. The deep groove ball bearing according to any one of claims 1 to 4, wherein the range is 04.
The cage is composed of a cylindrical first divided cage made of a synthetic resin molded product, and a synthetic resin cylindrical second divided cage inserted inside the first divided cage. A notch that forms a circular pocket for holding the ball in a state where both the split cages are combined inside and outside on one side surface in the axial direction of the first split cage and the other side surface in the axial direction of the second split cage. And connecting means for non-separating the two divided cages in the axial direction in a combined state in which the first divided cage and the second divided cage form a circular pocket. The deep groove ball bearing according to any one of 1 to 5.
The connecting means is provided between the adjacent notches of the second split cage by providing an inward engagement claw at the tip of the pillar portion formed between the adjacent notches of the first split cage. An outward engaging claw is provided at the tip of the pillar portion, and the engaging claw of the first divided holder is engaged with an engaging recess formed in the outer diameter surface of the second divided holder, The deep groove ball bearing according to claim 6, wherein the engaging claw of the split cage is configured to engage with an engaging recess formed on an inner diameter surface of the first split cage.
The said notch part was made into circular shape exceeding a half circle in planar shape, it has a pair of opposing pocket claw in an opening end, and the cross-sectional shape was made into the spherical surface shape along the outer periphery of a ball | bowl. Deep groove ball bearing as described in.
The circumferential clearance formed between the engaging claw and the engaging recess is made larger than the circumferential pocket clearance between the pocket formed by the two notch portions facing each other in the radial direction and the ball accommodated in the pocket. A deep groove ball bearing according to claim 7 or 8.
The deep groove ball bearing according to claim 6 or 7, wherein the notch is formed into a planar U-shape that forms a cylindrical pocket in a combined state of the first divided cage and the second divided cage.
A circumferential clearance formed between the engaging claw and the engaging recess is larger than a circumferential pocket clearance between a pocket formed by two radially opposed notches and a ball accommodated in the pocket. The deep groove ball bearing according to claim 10.
The deep groove ball bearing according to any one of claims 6 to 11, wherein the first divided cage and the second divided cage are made of one of polyamide 46, polyamide 66, and polyphenylene sulfide.
The cage is composed of a split cage that is divided into two in the axial direction, and each of the split cages has a plurality of hemispherical pocket portions and a plurality of width dimensions that are the same as the width dimensions of the pocket portions. The coupling plate portion has a waveform that is alternately continuous in the circumferential direction, the outer diameter of the coupling plate portion of the two waveform split cages is the same diameter, and the pocket portion of one waveform split cage is the coupling plate portion On the other hand, the position is shifted to the inner diameter side, the pocket portion of the other waveform split cage is shifted to the outer diameter side with respect to the coupling plate portion, and the one waveform split cage is moved from the shoulder side where the height of the outer ring is high. 6. The device according to claim 1, wherein a pocket is provided between the hemispherical pocket portions by inserting the other corrugated cage into the bearing from the shoulder side having a low outer ring height. The deep groove ball bearing as described in the section.