JP2013092249A - Ball bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ball bearing which hardly causes an increase of torque and the friction of a crown-shaped cage, and is long in seizure life.SOLUTION: In the ball bearing 1, an axial cross section width is set as B, a value of B/H is set not smaller than 1.10 and not larger than 1.35 when a radial cross section width is set as H, a pocket bottom thickness of the crown-shaped cage 40 is set as T, and a value of T/Dw is set not smaller than 0.25 and not larger than 0.30 when the diameter of a ball 30 is set as Dw. By this, an absolute amount of sealable grease can be increased, the rigidity of the crown-shaped cage 40 is enhanced, and interference to the ball 30 and an outer ring 20 caused by the deformation of the crown-shaped cage 40 can be prevented. Accordingly, in the ball bearing 1, the increase of the torque and the friction of the crown-shaped cage 40 are hardly generated, and the seizure life becomes long.

Description

  The present invention relates to a ball bearing provided with a crown-shaped cage.

  Conventionally, various retainers for rotatably holding a plurality of balls that are rotatably incorporated between inner and outer rings are applied to rolling bearings. As an example, a crown-shaped cage is known. The crown-shaped cage is provided with a plurality of recesses at equal intervals along the circumferential direction. Each recess has an opening formed on one side thereof, and a pair of elastic pieces are raised from each opening so as to partially cover the opening. The opening diameter of each opening is narrowed by the piece. The ball is accommodated in a pocket formed by a pair of elastic pieces and a recess, and in this state, the ball is rotatably held without dropping from the pocket. Such a crown-shaped cage is incorporated in a state in which each ball is rotatably held between an inner ring and an outer ring of a rolling bearing, and rotates, for example, at the same speed as the revolution speed of each ball.

In recent years, the performance of various rotating machinery devices incorporating ball bearings has improved, and the relative rotational speed between the outer ring and the inner ring and the rotational speed of the crown-shaped cage have increased, resulting in a large centrifugal force applied to the crown-shaped cage. It has become. As a result, deformation of the crown-shaped cage (deformation toward the outer ring side) occurs, and when the crown-shaped cage interferes with the balls and the outer ring, torque increases and wear of the crown-shaped cage occurs. there were. In addition, in the case of ball bearings lubricated with grease, if the internal temperature rises due to the interference of the crown cage with the balls and outer ring, the deterioration of the grease is accelerated and the seizure life is shortened. In addition, it is essential to ensure the rigidity of the crown cage under high speed conditions.
In Patent Document 1, the thickness of the crown-shaped cage is reduced as it goes to the distal end side of the elastic piece, and the elastic piece is inclined in the direction toward the diametrically inward direction of the ball bearing. A technique for preventing interference with the inner surface of the outer ring caused by deformation is described.

JP 2000-161365 A

However, in the above technique, even if interference with the inner ring surface of the outer ring caused by deformation of the crown-shaped cage can be prevented, interference with the ball cannot be prevented. , The strength may be insufficient.
Accordingly, an object of the present invention is to solve the above-described problems of the prior art, and to provide a ball bearing having a long seizure life that is less likely to increase torque and wear the crown cage.

  In order to solve the above problems, a ball bearing according to an aspect of the present invention includes an inner ring having a raceway groove on an outer peripheral surface and a raceway groove on the inner peripheral surface facing the raceway groove of the inner ring. A cross section in the axial direction of a ball bearing comprising an outer ring arranged in the direction, a plurality of balls rotatably arranged between the both raceway grooves, and a crown-shaped cage that rotatably holds the plurality of balls When the width is B and the radial cross-sectional width is H, the value of B / H is 1.10 or more and 1.35 or less, and there are a plurality of recesses for holding the balls of the crown-shaped cage, When the length from the bottom of the concave portion to the other end in the axial direction is T, and the diameter of the ball is Dw, provided at one end in the axial direction with a gap along the circumferential direction, The value of T / Dw is 0.25 or more and 0.30 or less.

In the ball bearing, when the radius of curvature of at least one of the inner ring raceway groove and the outer ring raceway groove is R, the value of R / Dw is 0.52 or more and 0.56. The following is preferable.
Further, in the ball bearing, the crown-shaped cage is made of at least one synthetic resin selected from nylon 46, nylon 66, polyphenylene sulfide, polytetrafluoroethylene, and polyether ether ketone, or glass fiber in the synthetic resin. And at least one of carbon fibers is preferably formed from a synthetic resin composition containing 10% by mass or more and 40% by mass or less.

The ball bearing further includes a grease containing a thickener and a base oil, the thickener is a diurea compound, and the base oil has a kinematic viscosity at a temperature of 40 ° C. of 15 mm ² / s to 50 mm ² / The trimethylol propane ester oil is s or less, and the grease preferably contains 80% by mass to 90% by mass of the trimethylol propane ester oil.

That is, the ball bearing according to the present invention is preferably sealed with grease having the following configurations (a) and (b).
(a) includes a thickener and a base oil, the thickener is a diurea compound, the base oil is trimethylolpropane ester oil, and the content of the base oil is the sum of the thickener and the base oil. It is 80 mass% or more and 90 mass% or less by the ratio with respect to mass.
(b) The kinematic viscosity of the base oil at a temperature of 40 ° C. is 15 mm ² / s or more and 50 mm ² / s or less.

The ball bearing of the present invention is preferably sealed with grease having the following configurations (c) to (f).
(c) includes a thickener and a base oil, the thickener is an aliphatic diurea compound, and the base oil is a mixed oil of poly α-olein (PAO) and a diester, and the content of the base oil However, it is 85 mass% or more and 90 mass% or less by the ratio with respect to the total mass of a thickener and base oil.
(d) The kinematic viscosity of the base oil at a temperature of 40 ° C. is 15 to 35 mm ² / s.
(e) A sulfur-based additive is included, and the content of the sulfur-based additive is 0.1% by mass or more and 5.0% by mass or less in a ratio to the total mass of the thickener and the base oil.
(f) The penetration is 265 or more and 295 or less.

  The diurea compound is represented by the following general formula (1), the one in which R1 and R3 at the terminals are aliphatic hydrocarbon groups is an aliphatic diurea, and the one that is an aromatic hydrocarbon group is an aromatic diurea, A cycloaliphatic hydrocarbon group is an alicyclic diurea.

  As the diurea compound of the constitution (a), in the above general formula (1), R2 is an aromatic hydrocarbon group having 6 to 15 carbon atoms, and R1 and R3 are cyclohexyl groups or carbon atoms having 6 to 20 carbon atoms (preferably carbon atoms). What is a linear or branched alkyl group of Formula 18) can be used. A diurea compound more preferable as the diurea compound of the configuration (a) is an aliphatic / alicyclic group in which R1 is a cyclohexyl group and R3 is a linear or branched alkyl group having 6 to 20 carbon atoms (preferably 18 carbon atoms). It is a type diurea.

The aliphatic diurea compound having the constitution (c) is an aliphatic hydrocarbon having the general formula (1), wherein R2 is an aromatic hydrocarbon group having 6 to 15 carbon atoms, and R1 and R3 are 9 to 19 carbon atoms. What is the base can be used.
Further, the ball bearing can be used for a motor or a generator of an electric vehicle or a hybrid electric vehicle (that is, for use in supporting a rotating shaft of a motor or a generator constituting the electric vehicle or the hybrid electric vehicle).

  The ball bearing of the present invention specifies the value of B / H when the axial sectional width is B and the radial sectional width is H, and is provided at one axial end of the crown-shaped cage. The value of T / Dw when the length from the bottom of the concave part to the other end in the axial direction is T and the diameter of the ball is Dw is specified. As a result, the absolute amount of grease that can be enclosed can be increased, the rigidity of the crown-shaped cage can be increased, and interference with the ball and outer ring due to deformation can be prevented. Therefore, the ball bearing of the present invention hardly increases torque and wears the crown cage, and has a long seizure life.

It is an axial sectional view showing the structure of a deep groove ball bearing according to an embodiment of the present invention. It is a perspective view which shows the crown-shaped cage used for the deep groove ball bearing which concerns on embodiment of this invention. It is the figure which showed the relationship between the value of T / Dw, and the value of dmN. It is the figure which showed the relationship between the inner ring PV value and the advance / delay amount value, and the R / Dw value. It is the figure which showed the bending elastic modulus of the synthetic resin composition.

DESCRIPTION OF EMBODIMENTS Embodiments of a ball bearing according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is an axial sectional view showing the structure of a ball bearing 1 according to an embodiment of the present invention. FIG. 2 is a perspective view of a crown-shaped cage 40 used in the ball bearing 1 according to the present embodiment.
1 is a deep groove ball bearing, and includes an inner ring 10 having a raceway groove 10a on the outer peripheral surface, an outer ring 20 having a raceway groove 20a facing the raceway groove 10a of the inner ring 10 on an inner peripheral surface, and both raceway grooves. A plurality of balls 30 that are rotatably arranged between 10a and 20a, a crown-shaped cage 40 that rotatably holds the balls 30 between the inner ring 10 and the outer ring 20, and a non-contact type that is supported by the outer ring 20. The seals 50 and 50 are provided.

In the bearing inner space 60 surrounded by the inner ring 10, the outer ring 20, and the seals 50, 50, grease is used as a lubricant that lubricates between the raceway grooves 10 a, 20 a and the rolling surface 30 a of the ball 30. Is enclosed. The seal 50 and grease may not be provided, and lubricating oil may be used as a lubricant. In the ball bearing 1 of the present embodiment, the inner ring 10 and the outer ring 20 are relatively rotatable through the rolling of the balls 30.
The crown-shaped cage 40 is a substantially annular member, and a plurality of concave portions 41 for inserting the balls 30 are provided at one end in the axial direction at intervals along the circumferential direction, and are adjacent to each other. A convex portion 43 is formed between the concave portions 41. Further, the plurality of concave portions 41 have a shape that follows the contour shape of the ball 30, and specifically, a spherical shape.

Further, the recess 41 has a pair of elastic pieces 42 and 42 for holding the ball 30 inserted in the recess 41 so that the opening of the recess 41 is narrowed from the tip of the protrusion 43 to the recess 41 on both sides. They are launched facing each other. A pocket P having a shape along the contour of the ball 30 is formed by the recess 41 and the inner side surfaces of the pair of elastic pieces 42 and 42.
For example, when the ball 30 is pushed toward the recess 41 from a state in which the ball 30 is positioned between the pair of elastic pieces 42, 42, the ball 30 is pressed by a pressing force (load) at that time. Is elastically deformed to the outside and the opening diameter is expanded, so that the ball 30 can be inserted into the recess 41 through the opening and incorporated.

At this time, the ball 30 is accommodated in the pocket P formed by the pair of elastic pieces 42, 42 and the recess 41 by elastically restoring the pair of elastic pieces 42, 42 to the original shape and narrowing the opening diameter again. In this state, it is held rotatably without dropping from the pocket P. The crown-shaped cage 40 is incorporated between the inner ring 10 and the outer ring 20 in a state where each ball 30 is rotatably held, and rotates at the same speed as the revolution speed of each ball 30.
The crown-shaped cage 40 has a length (hereinafter referred to as “pocket bottom thickness”) from the bottom of the recess 41 to the axial end opposite to the one end in the axial direction where the recess 41 is provided. ) Is T and the diameter of the ball 30 is Dw, the T / Dw value is 0.25 or more and 0.30 or less.

  Thereby, the rigidity of the crown-shaped cage 40 is increased, and even when used under high-speed conditions, interference with the balls 30 and the outer ring 20 due to deformation of the crown-shaped cage 40 due to centrifugal force can be prevented. If the value of T / Dw is less than 0.25, there is a possibility that interference with the ball 30 and the outer ring 20 may not be sufficiently prevented. On the other hand, even if the value of T / Dw exceeds 0.30, This is because the effect of preventing interference with the ball 30 and the outer ring 20 is not improved.

In addition, when a crown type cage having a pocket bottom thickness T with a T / Dw value of 0.25 or more is incorporated into a conventional general ball bearing, the pocket bottom thickness becomes too large. There is a risk of interference. Also, even if there is no interference, if the clearance between the seal and the crown cage becomes small, grease will leak easily, so by increasing the axial bottom section width of the ball bearing by increasing the pocket bottom thickness, It is preferable to maintain the clearance between the cage and the seal.
Specifically, when the cross-sectional width of the ball bearing 1 is increased in both directions of the shaft with the ball 30 as the center, the axial cross-sectional width B is set to be equal to the diameter Dw of the ball 30 relative to a conventional general ball bearing. It is necessary to increase it by 20% or more. In this case, if the raceway grooves 10a and 20a of the inner and outer rings are formed so as to be shifted in one axial direction, an increase in the axial sectional width B can be suppressed, but this is not preferable because the cost increases.

In addition, increasing the axial cross-sectional width B increases the absolute amount of grease to be enclosed, so that an effect of improving the seizure life can be expected. However, if the axial cross-sectional width B is too large, the cost increases and the assemblability deteriorates. Therefore, the increase in the axial cross-sectional width B is preferably 20% to 30% of Dw. Therefore, in the ball bearing 1, when the axial sectional width is B and the radial sectional width is H, the value of B / H needs to be 1.10 or more and 1.35 or less.
The material of the crown-shaped cage 40 is not particularly limited, and examples thereof include synthetic resin, metal (for example, copper alloy), etc. From the viewpoint of formability and assemblability when the ball 30 is incorporated into the recess 41, Synthetic resins are preferred.

The type of the synthetic resin constituting the crown-shaped cage 40 is not particularly limited as long as it has characteristics such as strength and heat resistance necessary for the cage, but nylon 46, nylon 66, Polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), polyether ether ketone (PEEK) and the like are preferable. The crown-shaped cage 40 may be used alone or in combination of two or more of the above synthetic resins.
Furthermore, the crown-shaped cage 40 is preferably made of a synthetic resin composition containing at least one of glass fiber (GF) and carbon fiber (CF) in the above synthetic resin. This is because heat resistance and strength characteristics are excellent.

For example, a synthetic resin composition in which glass fiber is contained in at least one synthetic resin of nylon 46 and nylon 66 is preferable. FIG. 5 shows the bending elastic modulus at a temperature of 120 ° C. of a crown-shaped cage 40 manufactured by using nylon 46 as a synthetic resin and containing glass fibers. Thereby, even if it contains 40 mass% or more of glass fiber contained in a synthetic resin, it turns out that heat resistance and an intensity | strength characteristic do not improve.
Therefore, the glass fiber content is preferably 10% by mass or more and 40% by mass or less. If the content is less than 10% by mass, the desired heat resistance and strength characteristics may not be obtained. On the other hand, even if the content exceeds 40% by mass, the heat resistance and strength characteristics are not improved. This is because moldability is lowered.

  Moreover, it is preferable that the crown-shaped cage 40 used under high-speed conditions is composed of a synthetic resin composition in which the synthetic resin contains 10% by mass or more and 40% by mass or less of carbon fibers. Under further high speed conditions, the crown-shaped cage 40 is composed of at least one synthetic resin selected from polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), and polyetheretherketone (PEEK) with glass fiber and carbon fiber. More preferably, it is comprised from the highly rigid synthetic resin composition which contained 10 mass% or more and 40 mass% or less of at least one.

  Further, under high speed conditions, heat generation inside the rolling bearing due to sliding between the ball and the inner ring and the outer ring and generation of friction with the cage due to the advance and delay of the ball become problems. FIG. 4 shows the relationship between the R / Dw value, the inner ring PV value, and the advance / delay amount. In addition, the inner ring PV value and the advance / delay amount in the graph of FIG. 4 are shown as relative values when the inner ring PV value and the ball advance / delay amount are set to 1 when the R / Dw value is 0.5175. It is. FIG. 4 shows that it is preferable to set a large value of R, which is the groove radius of curvature of the raceway groove of the inner ring, in order to suppress the generation of heat and friction inside the rolling bearing.

  From such a viewpoint, in the ball bearing 1, the value of R, which is the groove curvature radius of the raceway groove 10a and the raceway groove 20a, is set larger than that of the conventional ball bearing, and the contact ellipse is made smaller. Thereby, generation | occurrence | production of the friction with the crown-shaped holder | retainer 40 by the heat_generation | fever inside the ball bearing 1 by the sliding with the ball | bowl 30 and the inner ring | wheel 10 and the outer ring | wheel 20 and the advance and delay of a ball | bowl can be reduced. Accordingly, high speed can be provided, and low heat generation and seizure resistance can be improved.

  Specifically, the ball bearing 1 preferably has a value of R / Dw of 0.52 or more and 0.56 or less, where R is the groove curvature radius of the raceway groove 10a and the raceway groove 20a. If the value of R / Dw is less than 0.52, there is a possibility that heat generation and friction generation inside the rolling bearing may not be sufficiently suppressed, while if it exceeds 0.56, the rolling fatigue life is reduced. This is because peeling is likely to occur. In addition, it is preferable that both the groove radius of curvature R of the raceway groove 10a and the groove radius of curvature R of the raceway groove 20a satisfy the above-described conditions. However, if any one of the groove curvature radii satisfies the above-described condition. Good.

  The grease of this embodiment includes a thickener and a base oil. The type of thickener is not particularly limited, and a thickener generally used in grease can be used without any problem. Examples thereof include metal soaps such as aluminum soap, barium soap, calcium soap, lithium soap and sodium soap, and metal composite soaps such as lithium composite soap, calcium composite soap and aluminum composite soap.

  In addition, urea compounds such as diurea, triurea, tetraurea, and polyurea, and inorganic compounds such as silica, silica gel, and bentonite can also be suitably used. Furthermore, urethane compounds, urea / urethane compounds, sodium terephthalamide, and the like can also be suitably used. These thickeners may be used individually by 1 type, and may be used in combination of 2 or more types as appropriate. However, from the viewpoint of heat resistance, it is preferable to use a diurea compound as the thickener.

  Moreover, the kind of base oil is not specifically limited, The mineral type lubricating oil and synthetic lubricating oil which are used as a base oil in a general lubricant can be used. Although the kind is not particularly limited, paraffinic mineral oils, naphthenic mineral oils, and mixed oils thereof can be used as mineral lubricants, and synthetic hydrocarbon oils can be used as synthetic lubricants. , Ether oil, ester oil and the like can be used. These lubricating oils may be used alone or in appropriate combination.

  Examples of the ester oil include diester oil, polyol ester oil, and aromatic ester oil. Specific examples of diester oils include dioctyl adipate (DOA), diisodecyl adipate (DIBA), dibutyl adipate (DBA), dioctyl azelate (DOZ), dibutyl sebacate (DBS), dioctyl sebacate (DOS), and the like. be able to.

Further, as a polyol ester oil, a pentaerythritol ester oil, a dipentaerythritol ester oil, a tripentaerythritol ester oil, a neopentyl diol ester oil, a trimethylolpropane ester oil, etc., into which an alkyl chain having 4 to 18 carbon atoms has been introduced. Can be mentioned.
Examples of the aromatic ester oil include trioctyl trimellitate (TOTM), tridecyl trimellitate, tetraoctyl pyromellitate and the like. These ester oils may be used alone or in appropriate combination. However, from the viewpoint of heat resistance, it is preferable to use trimethylolpropane ester as the base oil.

Further, as the base oil, it is more preferable to use a trimethylolpropane ester oil having a kinematic viscosity at a temperature of 40 ° C. of 15 mm ² / s to 50 mm ² / s. This is because if the kinematic viscosity at a temperature of 40 ° C. is less than 15 mm ² / s, the low-temperature fluidity is excellent, but the heat resistance at high temperatures is inferior, so that a sufficient lubrication life may not be satisfied. On the other hand, if the kinematic viscosity at a temperature of 40 ° C. exceeds 50 mm ² / s, the heat resistance at high temperature is excellent, but the low temperature fluidity is inferior. It is.

Further, the grease contains a thickener of 10% by mass to 20% by mass, and a trimethylolpropane ester oil having a kinematic viscosity at a temperature of 40 ° C. of 15 mm ² / s to 50 mm ² / s is 80% by mass to 90%. It is preferable to contain it by mass% or less. This is because if the amount of the thickener is too large, leakage of grease is suppressed, but the heat generated by the ball bearing 1 is increased and the lubrication life may be shortened. On the other hand, if the amount of the thickener is too small, the heat generation of the ball bearing 1 can be suppressed, but the leakage of grease increases and the lubrication life may be shortened.

  Furthermore, various additives may be added to the grease as necessary in order to improve various performances. As the additive, those generally used for lubricants can be used without any problem, and examples thereof include antioxidants, rust inhibitors, extreme pressure agents, oiliness improvers, metal deactivators and the like. Although it does not specifically limit as antioxidant, Antioxidants, such as amine type, such as phenyl-1- naphthylamine, phenol type, such as 2-tert- butylphenol, sulfur type, dithiophosphoric acid type, are mentioned.

In addition, this embodiment shows an example of this invention and this invention is not limited to this embodiment. For example, in the present embodiment, a deep groove ball bearing has been described as an example of a rolling bearing, but the present invention can be applied to various types of ball bearings other than deep groove ball bearings, for example, angular ball bearings. It can also be applied to.
Moreover, the ball bearing 1 of this embodiment is used suitably for the use which supports the rotating shaft of the motor or generator of an electric vehicle or a hybrid electric vehicle.

Hereinafter, the present invention will be described more specifically with reference to examples.
[1. About T / Dw value]
FIG. 3 shows the T / Dw value and the dmN value when the crown-shaped cage comes into contact with the ball or the outer ring due to the deformation due to centrifugal force for the deep groove ball bearing (outer diameter = 90 mm, inner diameter = 55 mm). This shows the relationship. The dmN value is an index of high-speed rotation of the rolling bearing, and is a value obtained by the product of the pitch circle diameter (mm) of the balls 30 and the rotation speed (min ⁻¹ ).

As a result, the T / Dw value of a crown-shaped cage used for a conventional general ball bearing is about 0.15, whereas it is used for a ball bearing used under high-speed conditions with a dmN value of 1 million or more. It can be seen that the T / Dw value of the crown-shaped cage required is 0.25 or more. The relationship between the T / Dw value and the dmN value shown in FIG. 3 is applied to a ball bearing having an inner diameter of 10 mm to 100 mm and an outer diameter of about 25 mm to 130 mm, and a rotational speed of 9000 min ⁻¹ or more. Is done.

[2. B / H value]
When using a crown-shaped cage with a pocket bottom thickness T with a T / Dw value of 0.25 or more, the clearance between the seal and the crown-shaped cage is kept at the same level as conventional ball bearings, while reducing costs. It is necessary to set the axial cross-sectional width B of the ball bearing so as to satisfy the condition of suppressing an increase in assembly and a decrease in assemblability. Table 1 shows the experimental results of Examples having various identification numbers prepared so as to satisfy this condition. Table 1 shows an inner diameter (mm), an outer diameter (mm), and a ball diameter Dw (mm) between a ball bearing according to the example and a ball bearing according to a comparative example of the identification number corresponding to the example. A radial cross-sectional width H (mm), an axial cross-sectional width B (mm), and a B / H value indicated by (outer diameter−inner diameter) / 2 are shown.

From Table 1, when using a crown cage with a pocket bottom thickness T with a T / Dw value of 0.25 or more, the clearance between the seal and the crown cage is equivalent to that of a conventional general ball bearing. In order to satisfy the condition of suppressing the increase in cost and the decrease in assembling property while maintaining, the increase in the axial section width B needs to be 20% or more of Dw, and the B / H value is 1.10 or more. It is understood that it is necessary to. On the other hand, if the axial section width B is too large, the cost increases and the assemblability deteriorates. Therefore, the increase in the axial section width B is preferably 30% or less of Dw. Therefore, the B / H value is preferably 1.35 or less.
As an example, a deep groove ball bearing having a nominal number 6011 will be described as an example. When the T / Dw value of the deep groove ball bearing with the nominal number 6011 is 0.25, the axial sectional width B of the example is 20.1, and the axial sectional width B of the comparative example is 18. The axial sectional width B of the example is increased by 2.1 mm from the axial sectional width B of the comparative example.

This increase amount is 2.0638 mm or more, which is 20% of the ball diameter Dw10.319 mm of the deep groove ball bearing of the nominal number 6011. Further, this increase amount is 3.0957 mm or less, which is 30% of the ball diameter Dw of 10.319 mm of the deep groove ball bearing having the nominal number 6011. Further, the B / H value is 1.15, which is 1.10 or more and 1.35 or less.
Table 2 shows the result of comparing the axial sectional width B when the B / H value satisfies the requirement of 1.10 or more and 1.35 or less and the axial sectional width B defined in the conventional JIS B1512. Shown in

  From Table 2, the axial sectional width B of the present embodiment can be paraphrased as 1.10 times or more and 1.20 times or less of the axial sectional width of a conventional general ball bearing defined in JIS B1512. I understand.

[Experimental Examples 1-7]
[3. Bearing lubrication life test]
Each grease shown in Table 3 was sealed in a deep groove ball bearing (outer diameter = 90 mm, inner diameter = 55 mm, width = 21 mm) according to the present invention, and a bearing lubrication life test was performed. Each deep groove ball bearing is a sealed deep groove ball bearing to which a non-contact hard rubber seal is attached.
Thickeners constituting each grease include aliphatic and fatty acids in which R2 in the general formula (1) is an aromatic hydrocarbon group, R1 is a cyclohexyl group, and R3 is a linear alkyl group having 18 carbon atoms. A cyclic diurea was prepared.

As the base oil, trimethylolpropane ester oil and pentaerythritol ester oil, which are polyol ester oils, and dioctyl sebacate, which is a diester oil, were prepared. As trimethylol propane ester oil, four types having different kinematic viscosities at 40 ° C. were prepared.
By mixing the thickener and each base oil so that the content of the base oil becomes each value of Table 3 at a ratio to the total mass of the thickener and the base oil, each bearing of Experimental Examples 1 to 7 Each grease used was obtained.

In the test, grease of 30% by volume of the bearing inner space volume was sealed in the bearing inner space of each deep groove ball bearing, and the inner ring rotation speed was 14000 min ⁻¹ , the bearing outer ring temperature was 120 ° C., and the radial load was 2000 N. The time until the seizure occurred was determined as the bearing lubrication life. Table 3 shows the results. The results are shown as relative values when the bearing lubrication life of Experimental Example 3 is 1.0. Further, the base oil content in the table indicates the ratio of the base oil when the mass of the whole grease composed of the base oil and the thickener is 100% by mass.

  From Table 3, the grease encapsulated in the deep groove ball bearings of Experimental Examples 1 and 2 is that the type of thickener is diurea, the type of base oil is trimethylolpropane ester oil, and the base oil content is 80% by mass or more. Since all three conditions of mass% or less are satisfied, it can be seen that the bearing lubrication life is longer than those of Experimental Examples 3 to 7 that do not satisfy at least one of the three conditions. In this test, when the bearing lubrication life exceeded 1.5, it was evaluated as acceptable, and when it was 1.5 or less, it was evaluated as unacceptable.

[4. About grease leakage test]
Under the test conditions described in [3. Bearing lubrication life test], the amount of grease leakage 20 hours after the start of rotation was measured. The results are shown in Table 3. The results indicate that the grease leakage is 10% by mass or less of the total grease enclosed in each deep groove ball bearing. Indicated.
From Table 3, the grease encapsulated in the deep groove ball bearings of Experimental Examples 1 and 2 is that the type of thickener is diurea, the type of base oil is trimethylolpropane ester oil, and the base oil content is 80% by mass or more. Since all three conditions of mass% or less are satisfied, it can be seen that the amount of grease leakage is small compared to Experimental Example 7 in which the base oil content does not satisfy the condition of 80 mass% or more and 90 mass% or less. .

[5. Low temperature fluidity test (low temperature torque test)]
About each rolling bearing of Table 3, the low temperature torque test prescribed | regulated to JISK2220 18. was performed on the conditions of temperature-40 degreeC. The low temperature torque was calculated from the average value of the readings of the torque measuring device over the last 15 seconds while rotating for 10 minutes. When the value of the low temperature torque in Experimental Example 3 is 1.0, the relative value is less than 1, and the pass value is evaluated.

From Table 3, the grease encapsulated in the deep groove ball bearings of Experimental Examples 1 and 2 is that the type of thickener is diurea, the type of base oil is trimethylolpropane ester oil, and the base oil content is 80% by mass or more. Since all three conditions of mass% or less are satisfied, the low temperature torque is lower than that of Experimental Example 5 in which the kinematic viscosity of the base oil at a temperature of 40 ° C. does not satisfy the condition of 15 mm ² / s to 50 mm ² / s. It turns out that it is low.
Further, the deep groove ball bearings of Experimental Examples 1 and 2 have low low temperature torque even compared to Experimental Example 6 in which grease that does not satisfy the condition that the base oil content is 80 mass% or more and 90 mass% or less is sealed. I understand.

[6. Comprehensive evaluation]
Deep groove ball bearings that have passed any of the above bearing lubrication life test, grease leakage test, and low-temperature fluidity test (low-temperature torque test) are diurea thickener and trimethylolpropane ester base oil. The deep groove ball bearings of Experimental Example 1 and Experimental Example 2 were filled with grease satisfying all three conditions of oil and base oil content of 80 mass% or more and 90 mass% or less.

On the other hand, the deep groove ball bearings of Experimental Examples 3 to 7 in which grease that does not satisfy at least one of the above three conditions is sealed have a bearing lubrication life test, a grease leakage test, a low temperature fluidity test (low temperature torque test). ) Has failed at least one test.
For these reasons, a grease satisfying all three conditions, that is, the type of thickener is diurea, the type of base oil is trimethylolpropane ester oil, and the base oil content is 80% by mass to 90% by mass is used. It can be seen that the deep groove ball bearing has little leakage of grease, excellent low-temperature fluidity, and a long seizure life.

[Experimental Examples 8 to 16]
As the ball bearing 1 having the structure of FIG. 1, 18 deep groove ball bearings having an inner diameter of 55 mm, an outer diameter of 90 mm, a ball diameter (Dw) of 10.319 mm, and a B / H value of 1.2 were prepared. The seal 50 is made of hard rubber.
As a thickener constituting each grease, an aliphatic diurea in which R2 in the general formula (1) is an aromatic hydrocarbon group, R1 is a linear alkyl group, and R3 is a linear alkyl group was prepared. .

As the base oil, a poly α Orein kinematic viscosity at 40 ° C. is 50 mm ² / s, a diester oil, dioctyl sebacate kinematic viscosity at 40 ° C. is 12 mm ² / s to (DOS), the table What was mixed with each ratio shown in 4 was prepared.
As the sulfur additive, zinc dithiocarbamate was prepared.
Thickener, each base oil (mixed oil), and sulfur-based additive are ratios to the total mass of the thickener and base oil, and the contents of base oil and sulfur-based additive are the values shown in Table 4, respectively. By mixing in this manner, nine types of greases used in the bearings of Experimental Examples 8 to 16 were obtained. And each grease of the quantity equivalent to 30 volume% of bearing internal space volume was enclosed in the bearing internal space of each bearing, and each bearing of Experimental Examples 8-16 was assembled.

First, as a life test, each bearing of Experimental Examples 8 to 16 is continuously rotated under the conditions of an inner ring rotational speed of 14000 min ⁻¹ , a bearing outer ring temperature of 120 ° C., and a radial load of 2000 N, and the time until seizure occurs (bearing lubrication). Life). Further, the amount of grease leakage 20 hours after the start of rotation was measured.
Furthermore, the low temperature torque test prescribed | regulated to JISK2220 18. was done about each bearing of Experimental Examples 8-16 on the conditions of temperature -40 degreeC. That is, each bearing was continuously rotated for 10 minutes in a space of −40 ° C., and an average value of measured torque values in the last 15 seconds was calculated as a low temperature torque value. For each calculated low temperature torque value, a relative value (low temperature torque ratio) with the low temperature torque value of Experimental Example 3 in Table 3 as 1, was calculated.

  These results are shown in Table 4. The results in Table 4 are also shown as relative values when the bearing lubrication life of Experimental Example 3 in Table 3 is 1. The bearing lubrication life was determined to be acceptable when the relative value exceeded 1.5 and rejected when the relative value was 1.5 or less. As for the leakage of grease, it was determined to be acceptable (O) if the amount of leakage was 10% by mass or less of the entire grease encapsulated in each deep groove ball bearing, and rejected (X) if exceeding 10% by mass. Furthermore, regarding the low temperature fluidity, it was evaluated as acceptable if the low temperature torque ratio was less than 1.0, and rejected if it was 1.0 or more.

The following can be understood from the results of Table 4.
In the bearings of Experimental Examples 8 to 16, the base oil of the enclosed grease is a mixed oil of poly α-olein (PAO) and diester, and the base oil content is based on the total mass of the thickener and the base oil. The ratio is 85% by mass or more and 90% by mass or less. Moreover, the penetration degree is 265-290. That is, the grease sealed in the bearings of Experimental Examples 8 to 16 satisfies the configurations (c) and (f).

Among them, in the bearings of Experimental Examples 8 to 10 and 12 to 15, the kinematic viscosity at a temperature of 40 ° C. of the base oil contained in the enclosed grease is 15 to 35 mm ² / s (satisfying the configuration (d)). In the bearings of Experimental Examples 11 and 16, the kinematic viscosity deviates from 15 to 35 mm ² / s (configuration (d) is not satisfied). In the bearings of Experimental Examples 8 to 13 and 16, the content of the sulfur-based additive contained in the enclosed grease is 0.1% by mass or more and 5.0% by mass with respect to the total mass of the thickener and the base oil. In the bearings of Experimental Examples 14 and 15, the encapsulated grease does not contain a sulfur-based additive, or the content of the sulfur-based additive is within the above range. Deviates from (does not satisfy configuration (e)).
As described above, the bearings of Experimental Examples 8 to 10, 12 and 13 in which the grease satisfying all of the configurations (c) to (f) is sealed have the bearing lubrication life test, the grease leakage test, and the low temperature fluidity. Both tests (low temperature torque test) passed, there was little leakage of grease, excellent low temperature fluidity, and long seizure life.

In contrast, the bearing of the kinematic viscosity of the temperature 40 ° C. of the base oil contained in the enclosed grease is ^{13.0mm 2 / s (15mm 2 /} s less than) Experimental Example 11, the grease leakage is small Although it was excellent in low-temperature fluidity, the seizure life was short. The bearing of kinematic viscosity temperature 40 ° C. of the base oil contained in the enclosed grease is ^{45.0mm 2 / s (35mm 2 /} s larger) Experimental Example 16, although the grease leakage is small, low-temperature The fluidity was poor and the seizure life was not long.
Further, the bearing of Experimental Example 14 in which grease containing no sulfur-based additive was sealed had good low-temperature fluidity, but had a large amount of grease leakage and a short seizure life. The bearing of Experimental Example 15 in which grease containing a sulfur-based additive content of 6.0% by mass (exceeding 5.0% by mass) has little leakage of grease and good low-temperature fluidity. However, the seizure life was short.

DESCRIPTION OF SYMBOLS 1 Ball bearing 10 Inner ring 10a Raceway groove 20 Outer ring 20a Raceway groove 30 Ball 40 Crown-shaped cage 41 Recess 50 Seal 60 Bearing internal space B Axial cross-sectional width H Radial cross-sectional width T Pocket bottom thickness (the other side in the axial direction from the bottom of the recess) Length to end of
Dw Ball diameter R Groove radius of raceway groove

Claims (6)

An inner ring having a raceway groove on the outer peripheral surface, an outer ring having a raceway groove facing the raceway groove of the inner ring on the inner peripheral surface, and an outer ring disposed on the outer side of the inner ring, and a free-rolling arrangement between the both raceway grooves. Of a ball bearing provided with a plurality of balls and a crown-shaped cage that rotatably holds the plurality of balls, where B is an axial sectional width and H is a radial sectional width. The value is 1.10 or more and 1.35 or less,
A plurality of recesses for holding the balls of the crown-shaped cage are provided at one end in the axial direction at intervals along the circumferential direction, and the other end in the axial direction from the bottom of the recess A ball bearing characterized in that the value of T / Dw is 0.25 or more and 0.30 or less, where T is the length up to T and the diameter of the ball is Dw.   When the radius of curvature of at least one of the inner ring raceway groove and the outer ring raceway groove is R, the value of R / Dw is 0.52 or more and 0.56 or less. The ball bearing according to claim 1.   The crown-shaped cage is made of at least one synthetic resin selected from nylon 46, nylon 66, polyphenylene sulfide, polytetrafluoroethylene, and polyether ether ketone, or at least one of glass fiber and carbon fiber in the synthetic resin. The ball bearing according to claim 1 or 2, wherein one ball bearing is formed from a synthetic resin composition containing 10 mass% to 40 mass%. The ball bearing according to any one of claims 1 to 3, wherein grease having the following configurations (a) and (b) is enclosed.
(a) includes a thickener and a base oil, the thickener is a diurea compound, the base oil is trimethylolpropane ester oil, and the content of the base oil is the sum of the thickener and the base oil. It is 80 mass% or more and 90 mass% or less by the ratio with respect to mass.
(b) The kinematic viscosity of the base oil at a temperature of 40 ° C. is 15 mm ² / s or more and 50 mm ² / s or less. The ball bearing according to any one of claims 1 to 3, wherein grease having the following configurations (c) to (f) is enclosed.
(c) includes a thickener and a base oil, the thickener is an aliphatic diurea compound, and the base oil is a mixed oil of poly α-olein (PAO) and a diester, and the content of the base oil However, it is 85 mass% or more and 90 mass% or less by the ratio with respect to the total mass of a thickener and base oil.
(d) The kinematic viscosity of the base oil at a temperature of 40 ° C. is 15 to 35 mm ² / s.
(e) A sulfur-based additive is included, and the content of the sulfur-based additive is 0.1% by mass or more and 5.0% by mass or less in a ratio to the total mass of the thickener and the base oil.
(f) The penetration is 265 or more and 295 or less.   The ball bearing according to any one of claims 1 to 5, which is used for supporting a rotating shaft of a motor or a generator constituting an electric vehicle or a hybrid electric vehicle.

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