JP3326915B2 - Roller bearing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The roller bearing according to the present invention is used as a full-roller needle roller bearing for use in, for example, an automatic transmission for an automobile.

[0002]

2. Description of the Related Art For example, a roller bearing such as a full roller type needle roller bearing (a so-called needle bearing) is incorporated in a rotation supporting portion of a planetary gear mechanism of an automatic transmission for an automobile. In order to ensure the life of such a roller bearing, the rolling surface of a plurality of rollers and the raceway surface formed on the peripheral surface of a mating member facing the plurality of rollers, such as an outer raceway and an inner raceway, are required. It is necessary that the lubrication state of the rolling part, which makes line contact, is good. In particular, in the case of a planetary gear mechanism of an automatic transmission, a sufficient amount of lubricating oil to be supplied to the roller bearing mounting portion is not necessarily ensured, and therefore, consideration must be given to improving the lubrication state of the rolling portion.

Conventionally, the rolling surface and the raceway surface have been finished as smooth as possible to prevent metal contact between the roller and the mating member between the rolling surface and the raceway surface even with a small amount of lubricating oil. I was doing it.

[0004]

However, if the rolling surface and the raceway surface are simply finished to be smooth, heat is generated due to slippage between the rolling surface and the raceway surface. It has been pointed out that bearings may seize. That is, during operation of the roller bearing, a moment in a direction in which the central axis of each roller and the central axis of the mating member are made non-parallel (skew) may be applied to the plurality of rollers.

[0005] When the rollers are skewed, the resistance to rotation of each roller is extremely large as compared to before the skew, and the amount of heat generated at the roller bearings is significantly increased. In a remarkable case, there is a possibility that the roller bearing portion is seized.

In order to prevent the skew which causes such inconvenience, for example, Japanese Patent Publication No. 57-61933 discloses that the roughness of an outer raceway is larger (rougher) than that of an inner raceway.
In addition, a technique is described in which the friction coefficient between the rolling surface of each roller and the outer raceway is larger than the friction coefficient between the rolling surface of each roller and the inner raceway. However, in such a conventional technique, the effect of preventing roller skew is not always sufficient. If the moment is large, the roller skew cannot be sufficiently prevented, and there is a risk of seizure. The roller bearing of the present invention has been invented in view of such circumstances.

[0007]

A roller bearing according to the present invention comprises a plurality of rollers having an outer peripheral surface as a rolling surface and a raceway surface having a peripheral surface in line contact with the rolling surface, similarly to a conventional roller bearing. And a mating member. In particular, in the roller bearing of the present invention, the surface roughness of the rolling surface in the axial direction and the circumferential direction is 0.06 μmRa or less, and extends in the axial direction of the peripheral surface of the mating member. Surface roughness 0.08μmRa ~ 0.1
The surface roughness of the mating member in the axial direction is 50% of the height of the roughness peak from the top of the roughness peak.
The load ratio at a depth of is 70% or more.

[0008]

In the case of the roller bearing of the present invention configured as described above, a large number of lubricating oil flow paths are secured on the peripheral surface of the mating member in the circumferential direction, so that the rollers are skewed. Even if the heat is generated, the amount of heat generated by the heat is carried out by the lubricating oil flowing through the numerous flow paths. As a result, the temperature rise on the peripheral surface (track surface) of the mating member is suppressed, and the seizure resistance is improved.

This state will be described with reference to FIG. FIG. 1 shows that the contact state between the rolling surface 2 of the roller 1 and the inner raceway 4 which is a raceway surface provided on the outer peripheral surface of the inner race 3 is devised so that even when the roller 1 is skewed, the inner race 3 This suppresses the temperature rise. In the case of the roller bearing of the present invention, as is apparent from FIG. 1, the surface roughness of the inner ring raceway 4 is relatively rough (0.08 μm Ra〜) in the axial direction (left-right direction in FIG. 1).
0.15 μm Ra).

In addition, not only the surface roughness in the axial direction is increased, but also the height of the peak of the roughness is 50
The load ratio at a depth of% was 70% or more. This leads to the property that the surface of the inner raceway 4 has a relatively flat ridges 5, 5 and grooves 6, 6 alternately repeated as shown in FIG. That is, despite the relatively rough surface roughness, the load ratio is large, so that the grooves 6, 6 as described above are innumerably present on the surface of the inner raceway 4 at a relatively fine pitch. .

When the rollers 1 are skewed, the rolling surface 2 and the inner raceway 4 are strongly rubbed against each other and generate heat. The amount of heat generated by the heat is generated in the innumerable grooves 6 and 6 in a circle. It is carried away by the lubricant flowing in the circumferential direction. As a result, an increase in the surface temperature of the inner raceway 4 and the rolling surface 2 that comes into contact with the inner raceway 4 is suppressed.
And the rolling surface 2 are prevented from seizing. In addition, since the load ratio is sufficiently increased, no excessive surface pressure is generated at the contact portion between the inner raceway 4 and the rolling surface 2, and the inner raceway 4 and the rolling surface 2 are not separated. There is no possibility of damage to the slab.

On the other hand, FIG. 2 shows that the surface roughness in the axial direction (left-right direction in FIG. 2) is less than 0.08 μmRa, which is relatively smooth, and that the peak height is 50%. Load ratio is 7
A state of less than 0% is shown. When the surface of the inner raceway 4 has such a property, the flow path of the lubricating oil cannot be secured, so that the temperature rise during operation cannot be suppressed. If the flow ratio of the lubricating oil is to be ensured while the load ratio is insufficient, the surface roughness must be considerably increased. When the surface roughness is increased in this manner, an excessive surface pressure is generated at the contact portion between the inner raceway 4 and the rolling surface 2, and the inner raceway 4 and the rolling surface 2
In addition, since damage such as peeling easily occurs, it cannot be adopted.

[0013]

EXAMPLES In order to confirm the effects of the present invention, the results of experiments conducted by the inventor will be described with reference to FIGS.

FIG. 3 shows the apparatus used for the experiment. A hollow fixed shaft 8 is supported between a pair of holders 7a and 7b concentrically and spaced apart from each other so as to extend over both holders 7a and 7b. This fixed shaft 8
The lubricating oil is fed from one of the holders 7b into the inside, and the lubricating oil is discharged through the discharge port 9 around the fixed shaft 8. The outer peripheral surface of the fixed shaft 8 is the inner raceway 4 which is the raceway surface.

On the other hand, the outer ring 10 is
Is rotatably supported concentrically with the fixed shaft 8. That is, a plurality of rollers 1 and 1 are rotatably provided between an outer raceway 11 formed on the inner peripheral surface of the outer race 10 and the inner raceway 4, and the outer race 10 is rotatable around the fixed shaft 8. I support it. No retainer for retaining rollers 1 and 1 is provided.

A driven gear 12 is externally fitted and fixed to an outer peripheral surface of an end (right end in FIG. 3) of the outer ring 10.
And the drive gear 14 which is driven to rotate by the motor 13, thereby rotating the outer ring 10 at 16000 rpm. A pair of angular-type ball bearings 15, 15 combined back to back around the outer ring 10.
, A retaining ring 16 is provided. Then, a radial load of 2500 N and a moment load of 14 N · m are applied to the retaining wheel 16.

Using such a test apparatus, the inner raceway 4 on the outer peripheral surface of the fixed shaft 8 and the rolling surfaces 2, 2 of the rollers 1, 1 are used.
When the temperature of the inner ring raceway 4 was measured while changing the surface roughness, the results shown in the following Table 1 were obtained. In Table 1, the value of the surface roughness is the center line average roughness specified in JISB0601, and the unit is μmRa. The unit of the temperature of the inner raceway 4 is ° C., and the unit of the load ratio is%. The surface roughness of the inner raceway 4 in the circumferential direction was set to 0.04 μmRa or less.

[0018]

[Table 1]

As is clear from the description in Table 1, the roller bearing of the present invention can suppress the temperature rise of the inner ring raceway 4 portion lower than the conventional roller bearing. In addition, Comparative Examples 11 to
13 shows an example in which the rise in the inner ring temperature could not be suppressed because the surface roughness was insufficient (smooth).
Shows examples in which the rise in the inner ring temperature could not be suppressed due to the insufficient load ratio. Further, in the case of the roller bearing of the present invention, the temperature change of the inner ring raceway 4 was very small as shown in FIG. On the other hand, in the case of the conventional roller bearing, as shown in FIG. 5, the temperature of the inner ring raceway 4 greatly changed.

The surfaces of the constituent members can be processed into desired properties by using appropriate abrasive grains and binders of the grindstone and devising a processing method such as centerless processing. For example, by using a grindstone formed of fused alumina-based abrasive grains and a resinous binder, by appropriately setting the feed speed and the like of the workpiece and performing grinding, a member having a desired surface property Can be obtained.

When implementing the roller bearing of the present invention,
By making the surface roughness of the peripheral surface of the mating member such as the inner ring raceway 4 or the outer ring raceway in the circumferential direction equal to or less than 0.04 μmRa, the ratio of the axial roughness of the circumferential surface to the circumferential roughness is reduced. If the number is set to 2 or more, the skew itself of the roller 2 can be suppressed. Therefore, it is possible to further suppress the temperature rise during operation, and to further improve the effect of preventing the roller bearing from seizing. As described above, the skew of the roller 2 can be prevented by devising the properties of the peripheral surface of the mating member such as the inner raceway 4 or the outer raceway, as described in the specification of Japanese Patent Application No. Hei 5-2111045. It is.

[0022]

Since the roller bearing of the present invention is constructed and operates as described above, the amount of heat generated at the roller bearing portion can be reduced, and the risk of seizure of the roller bearing portion can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing a roller bearing of the present invention.

FIG. 2 is a perspective view schematically showing a conventional roller bearing.

FIG. 3 is a cross-sectional view of a test device performed to confirm the effects of the present invention.

FIG. 4 is a diagram showing a temperature change of a raceway surface of the roller bearing of the present invention.

FIG. 5 is a diagram showing a temperature change of a raceway surface of a conventional roller bearing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Roller 2 Rolling surface 3 Inner race 4 Inner raceway 5 Ridge part 6 Groove part 7a, 7b Holder 8 Fixed shaft 9 Discharge port 10 Outer race 11 Outer raceway 12 Follower gear 13 Motor 14 Drive gear 15 Ball bearing 16 Retaining ring

Continuation of the front page (56) References JP-A-3-234911 (JP, A) JP-A-7-42743 (JP, A) JP-A 2-154813 (JP, A) JP-A-5-306719 (JP) JP-A-1-220720 (JP, A) JP-A-2-154812 (JP, A) JP-A-62-1821 (JP, U) JP-B-57-61933 (JP, B1) (58) Field surveyed (Int.Cl. ⁷ , DB name) F16C 33/30-33/66

Claims (2)

(57) [Claims] 1. A roller bearing comprising: a plurality of rollers having an outer peripheral surface as a rolling surface; and a mating member having a peripheral surface as a raceway surface in linear contact with the rolling surface. The surface roughness in both the axial direction and the circumferential direction is 0.06 μm Ra or less, and the surface roughness in the axial direction of the peripheral surface of the mating member is 0.08 μm Ra to 0.15 μm Ra. A roller bearing having a load ratio of 70% or more at a depth of 50% of the height of the roughness peak from the top of the roughness peak with respect to the surface roughness in the axial direction of the roller bearing. 2. The roller bearing according to claim 1, wherein the peripheral surface of the peripheral surface of the mating member has a surface roughness of 0.04 μmRa or less.