JP2008175300A - Deep groove ball bearing - Google Patents

Abstract

A deep groove ball bearing capable of improving seizure resistance, wear resistance, and fatigue resistance of a cage and rolling elements and improving the durability and high-speed rotation performance of the bearing.
A deep groove ball bearing 10 includes an outer ring 11 having an outer ring raceway surface 11a on an inner peripheral surface, an inner ring 12 having an inner ring raceway surface 12a on an outer peripheral surface, and an outer ring raceway surface 11a and an inner ring raceway surface 12a. A plurality of rolling elements 13 interposed so as to be freely rollable, and a cage 14 that holds the rolling elements 13 at equal intervals in the circumferential direction. 03 ≦ C ≦ 0.20, 0.90 ≦ Cr ≦ 1.20, 0.15 ≦ Mo ≦ 0.30 is a corrugated cage, and the cage 14 is nitrided at 727 ° C. or less, and Hv650 It has the above surface hardness and a compound layer thickness of 1 to 20 μm.
[Selection] Figure 1

Description

  The present invention relates to a deep groove ball bearing provided with a cage, and particularly to a deep groove ball bearing suitable for high-speed rotation applications.

  Conventionally, as a cage used for a deep groove ball bearing, for example, a corrugated cage manufactured by press-forming a low carbon steel plate such as an SPCC material into a cage material is known. In this corrugated cage, two annular holding plates in which a ball holding portion bulging outward and a flat portion are formed at predetermined intervals in the circumferential direction are opposed to each other so that each ball holding portion forms a pocket portion. The flat portions are connected by rivets or the like (see, for example, Patent Document 1).

  In addition, a crown type cage is used for the cage of the deep groove ball bearing. This crown-shaped cage is formed by injection molding of synthetic resin, etc., and a pocket portion is formed to hold a plurality of balls so as to be able to roll at equal intervals in the circumferential direction, and the inner circumferential surface of this pocket portion is formed. A pair of claw portions protruding in the axial direction are provided at both circumferential ends. In addition, an opening is formed between the pair of claws, and the ball is pushed through the opening while the pair of claws are spread out, and the ball is inserted into the pocket through a small gap. (For example, refer to Patent Document 2).

JP-A-10-238544 JP 2000-170772 A

  By the way, in recent years, rolling bearings used in automobiles are expected to increase in speed. When the rolling bearing described in Patent Document 1 is applied to such high-speed rotation applications, the rolling bearings and rolling parts of the cage are used. The PV value between the moving bodies (balls) may increase and seizure damage may occur, and the cage and rolling elements slide at a high speed, causing the cage balls and rolling balls to become steel balls. Wear may occur, and furthermore, fatigue damage may occur due to a load of centrifugal force on the cage and a load applied due to advance and delay of the rolling elements.

  In addition, when the rolling bearing described in Patent Document 2 is applied to high-speed rotation applications, since it is a resin cage, seizure resistance and wear resistance are improved, but creep damage is caused by operating temperature and centrifugal force. Could occur.

  The present invention has been made to eliminate such inconveniences, and its purpose is to improve the seizure resistance, wear resistance and fatigue resistance of the cage and rolling elements, and to improve the durability and durability of the bearing. An object of the present invention is to provide a deep groove ball bearing capable of improving high-speed rotation performance.

The above object of the present invention can be achieved by the following constitution.
(1) An outer ring having an outer ring raceway surface on an inner peripheral surface, an inner ring having an inner ring raceway surface on an outer peripheral surface, and a plurality of rolling elements interposed between the outer ring raceway surface and the inner ring raceway surface so as to be freely rollable. And a deep groove ball bearing comprising a cage that holds the rolling elements at equal intervals in the circumferential direction, the cage having a chemical composition of wt%, 0.03 ≦ C ≦ 0.20, 0.90. ≦ Cr ≦ 1.20, 0.15 ≦ Mo ≦ 0.30 is a corrugated cage, and the cage is nitrided at 727 ° C. or less, has a surface hardness of Hv650 or more, and a compound of 1 to 20 μm A deep groove ball bearing characterized by having a layer thickness.
(2) The rolling element is a steel ball, the nitrogen concentration on the surface thereof is 0.1% or more and 0.6% or less, and the surface hardness is Hv750 to 1000, characterized in that the deep groove according to (1) Ball bearing.
(3) The deep groove ball according to (2), wherein the rolling element is made of steel having a chemical composition of wt% and 0.40 ≦ Si ≦ 0.80 and 0.90 ≦ Mn ≦ 1.25. bearing.

  According to the deep groove ball bearing of the present invention, the cage has a chemical composition of wt%, 0.03 ≦ C ≦ 0.20, 0.90 ≦ Cr ≦ 1.20, 0.15 ≦ Mo ≦ 0.30. The corrugated cage is made of steel, and the cage is nitrided at 727 ° C. or less, and has a surface hardness of Hv650 or more and a compound layer thickness of 1 to 20 μm. Abrasion and fatigue resistance can be improved. Moreover, since the cage is heat-treated without undergoing martensitic transformation, deformation of the cage can be suppressed. As a result, the durability and high-speed rotation performance of the bearing can be improved. Furthermore, since favorable press workability can be ensured, manufacturing costs can be reduced.

  Further, according to the deep groove ball bearing of the present invention, the rolling element is a steel ball, the surface has a nitrogen concentration of 0.1% to 0.6%, and the surface hardness is Hv750 to 1000. The wear resistance and seizure resistance between the rolling device and the rolling element can be improved. Thereby, durability and high-speed rotation performance of the bearing can be further improved.

  Furthermore, according to the deep groove ball bearing of the present invention, the rolling element is made of steel with a chemical composition of wt% and 0.40 ≦ Si ≦ 0.80, 0.90 ≦ Mn ≦ 1.25. Since carbonitride is miniaturized, the friction coefficient between the cage and the rolling element can be reduced, and the wear resistance and seizure resistance between the cage and the rolling element can be improved. . Thereby, durability and high-speed rotation performance of the bearing can be further improved.

Hereinafter, an embodiment of a deep groove ball bearing according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a partially cutaway perspective view for explaining a deep groove ball bearing according to the present invention.

  As shown in FIG. 1, the deep groove ball bearing 10 of this embodiment includes an outer ring 11 having an outer ring raceway surface 11a on an inner peripheral surface, an inner ring 12 having an inner ring raceway surface 12a on an outer peripheral surface, an outer ring raceway surface 11a and an inner ring. A plurality of balls (rolling elements) 13 interposed between the raceway surfaces 12a so as to be freely rollable, and a waveform holder (holder) 14 that holds the balls 13 at equal intervals in the circumferential direction.

  The corrugated cage 14 includes a pair of cage members 15, 15 each having a spherical recess 16 for holding the ball 13 and a flat surface 17 formed at predetermined intervals in the circumferential direction. 16 and 16 are made to face each other so as to form a pocket portion 18, and the flat portions 17 and 17 are joined together by a rivet 19 to be assembled. The corrugated cage 14 suppresses the wear of the sliding portion between the pocket portion 18 and the ball 13 by forming an oil film of lubricating oil between the pocket portion 18 and the ball 13.

  In this embodiment, the waveform holder 14 has a chemical composition of wt%, and 0.03 ≦ C ≦ 0.20, 0.90 ≦ Cr ≦ 1.20, and 0.15 ≦ Mo ≦ 0.30. It is made of steel and is nitrided at 727 ° C. or lower, and has a surface hardness of Hv650 or higher and a compound layer thickness of 1 to 20 μm. In addition, the corrugated cage 14 has insufficient seizure resistance and wear resistance when the chromium (Cr) and molybdenum (Mo) of the steel material is less than the lower limit concentration, and the formation of the diffusion layer is also insufficient. Therefore, fatigue resistance is lowered, and if the upper limit concentration is exceeded, economic efficiency is lowered. Further, the thickness of the compound layer of the waveform holder 14 is not effective when it is less than 1 μm, and the economic efficiency is lowered when it exceeds 20 μm.

  Moreover, in this embodiment, the ball | bowl 13 is a steel ball, The nitrogen concentration of the surface is 0.1% or more and 0.6% or less, and surface hardness is Hv750-1000. In the case of the ball 13, when the surface nitrogen concentration is less than 0.1% and the surface hardness is less than Hv750, the seizure resistance and the wear resistance are insufficient. When the surface hardness exceeds Hv1000, the crushing value decreases.

  Furthermore, in the present embodiment, the balls 13 are made of steel having a chemical composition of wt% and 0.40 ≦ Si ≦ 0.80 and 0.90 ≦ Mn ≦ 1.25. In addition, the ball 13 has insufficient seizure resistance and wear resistance when the silicon (Si) and manganese (Mn) of the steel, which is the material, is less than the lower limit concentration, and the economic efficiency is reduced when the upper limit concentration is exceeded. .

  As described above, according to the deep groove ball bearing 10 of the present embodiment, the corrugated cage 14 has a chemical composition of wt%, 0.03 ≦ C ≦ 0.20, 0.90 ≦ Cr ≦ 1.20. Made of steel of 0.15 ≦ Mo ≦ 0.30, nitrided at 727 ° C. or less, and having a surface hardness of Hv650 or higher and a compound layer thickness of 1 to 20 μm, the seizure resistance of the corrugated cage 14 , Wear resistance and fatigue resistance can be improved. Further, since the waveform holder 14 is heat-treated without undergoing martensitic transformation, deformation of the waveform holder 14 can be suppressed. As a result, the durability and high-speed rotation performance of the bearing 10 can be improved. Furthermore, since favorable press workability can be ensured, manufacturing costs can be reduced.

  Further, according to the deep groove ball bearing 10 of the present embodiment, the balls 13 are steel balls, the surface has a nitrogen concentration of 0.1% to 0.6% and a surface hardness of Hv750 to 1000. The wear resistance and seizure resistance between the corrugated cage 14 and the ball 13 can be improved. Thereby, the durability and high-speed rotation performance of the bearing 10 can be further improved.

  Furthermore, according to the deep groove ball bearing 10 of the present embodiment, the ball 13 is made of steel with a chemical composition of wt% and 0.40 ≦ Si ≦ 0.80, 0.90 ≦ Mn ≦ 1.25. Since the surface carbonitride is miniaturized, the friction coefficient between the corrugated cage 14 and the ball 13 can be reduced, and the wear resistance and seizure resistance between the corrugated cage 14 and the ball 13 can be reduced. Can be improved. Thereby, the durability and high-speed rotation performance of the bearing 10 can be further improved.

  Below, each test performed in order to confirm the effect of the deep groove ball bearing 10 (invention example) of this invention is demonstrated.

Standard design deep groove ball bearings (JIS nominal number 6011, inner diameter φ55 mm × outer diameter φ90 mm × width 18 mm, PCD 72.5 mm) are used for the rolling bearings of the present invention and the conventional examples used for each test, and the respective specifications. Is as follows.
[Invention example specifications]
(Retainer)
・ Material: Chromium molybdenum steel SCM415
-Surface treatment: nitriding at 727 ° C
Surface hardness Hv650 or more
Compound layer thickness 1-20μm
(ball)
・ Material: SUJ2
・ Surface treatment: Surface nitrogen concentration 0.1% to 0.6%
Surface hardness Hv750-1000
[Conventional example specifications]
(Retainer)
・ Material: SPCC
・ Surface treatment: None (ball)
・ Material: SUJ2
・ Surface treatment: None

[High-speed rotation test 1]
In this test, the present invention example and the conventional example were prepared one by one, each was rotated under the following test conditions, the state of the cage was always observed, and the state of the cage and ball after rotation was observed. The results are shown in Tables 1 and 2.

The test conditions are as follows.
Rotation speed: 15000rpm
Load: 2000N
Lubricating oil: ATF for automobiles
Lubrication method: Forced lubrication Lubrication temperature: 80 ° C

  As apparent from Table 1, in the conventional example, the cage was seized at 46.4 h, whereas in the example of the present invention, no abnormality was confirmed even after 100 hours had elapsed, and normal termination was achieved. Further, as is apparent from Table 2, in the conventional example, significant wear has occurred on the pocket sliding surface and balls of the cage, whereas in the present invention example, the pocket sliding surface of the cage is minor. There was no particular problem with the balls, as only a slight sliding trace was confirmed. From these facts, it was found that the examples of the present invention can improve the seizure resistance, wear resistance, and fatigue resistance of the cage, and can improve the durability and high-speed rotation performance of the bearing.

[High-speed rotation test 2]
In this test, Reference Example 1 in which a ball having a surface nitrogen concentration of 0.05% was incorporated in a deep groove ball bearing of the present invention specification and a ball having a surface nitrogen concentration of 0.10% in the deep groove ball bearing of the present invention specification. Example 1 of the present invention incorporating the present invention and Example 2 of the present invention incorporating the ball having a surface nitrogen concentration of 0.40% in the deep groove ball bearing of the present invention specification, one by one, and each of the following test conditions Rotated with, and observed the state of the ball after rotation. The results are shown in Table 3.

The test conditions are as follows.
Rotation speed: 15000rpm
Load: 2000N
Lubricating oil: ATF for automobiles
Lubrication method: Forced lubrication Lubrication temperature: 140 ° C
Test time: 50h

  As is apparent from Table 3, in the reference example 1, the ball was worn, whereas in the inventive example 1, a slight sliding mark was generated in the ball. In the inventive example 2, the problem was particularly confirmed. There wasn't. From this, in the present invention example, it is possible to prevent the wear of the cage due to the direct metal contact between the pocket portion and the ball and the increase of the PV value, and the durability and high-speed rotation performance of the bearing can be further improved. I understood.

[High-speed rotation test 3]
In this test, Example 3 of the present invention in which a ball made of SUJ3 steel having a surface nitrogen concentration of 0.4% was prepared in a deep groove ball bearing of the specification of the Example of the present invention, and Example 3 of the present invention was rotated under the following test conditions. The state of the bearing after rotation was observed. The SUJ3 steel has a chemical composition of wt%, and 0.40 ≦ Si ≦ 0.80 and 0.90 ≦ Mn ≦ 1.25.

The test conditions are as follows.
Rotational speed: 30000 rpm
Load: 2000N
Lubricating oil: ATF for automobiles
Lubrication method: Forced lubrication Lubrication temperature: 160 ° C
Test time: 10h

  As a result of the test, since no particular problem was found in Invention Example 3, it was found that Invention Example 3 could withstand the severe test conditions described above. From this, the example of the present invention can prevent seizure due to an increase in PV value between the pocket portion of the cage and the ball, and can further improve the durability and high-speed rotation performance of the bearing. all right.

It is a partially cutaway perspective view for explaining a deep groove ball bearing according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Deep groove ball bearing 11 Outer ring 11a Outer ring raceway surface 12 Inner ring 12a Inner ring raceway surface 13 Ball (rolling element)
14 Waveform holder (Retainer)
15 Cage member 16 Spherical concave portion 17 Flat portion 18 Pocket portion 19 Rivet

Claims (3)

An outer ring having an outer ring raceway surface on an inner peripheral surface, an inner ring having an inner ring raceway surface on an outer peripheral surface, and a plurality of rolling elements interposed between the outer ring raceway surface and the inner ring raceway surface in a freely rollable manner; A deep groove ball bearing comprising a cage for holding the rolling elements at equal intervals in the circumferential direction,
The cage is a corrugated cage made of steel having a chemical composition of wt% and 0.03 ≦ C ≦ 0.20, 0.90 ≦ Cr ≦ 1.20, and 0.15 ≦ Mo ≦ 0.30. ,
The cage is nitrided at 727 ° C. or less, and has a surface hardness of Hv650 or more and a compound layer thickness of 1 to 20 μm.   2. The deep groove ball bearing according to claim 1, wherein the rolling element is a steel ball having a nitrogen concentration of 0.1% to 0.6% and a surface hardness of Hv750 to 1000. .   3. The deep groove ball bearing according to claim 2, wherein the rolling element is made of steel having a chemical composition of wt% and 0.40 ≦ Si ≦ 0.80 and 0.90 ≦ Mn ≦ 1.25.

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