JP2552643Y2 - Tapered roller bearing - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tapered roller bearing in which a flange extending radially outward is provided at one axial end of an inner ring.

[0002]

2. Description of the Related Art Conventionally, various improvements have been made to tapered roller bearings in order to reduce rotational torque. Conventionally, in order to achieve such a low torque, the surface roughness of the tapered roller guide surface of the radially outward flange provided at one axial end of the inner ring is set as small as possible to achieve a smooth surface. It is devised to be a surface.

[0003]

Meanwhile, in a tapered roller bearing used to support an input pinion gear of a differential of an automobile, the rotational torque of the tapered roller bearing is controlled so that a preload value falls within a predetermined range. It is considered that it is desirable to use a tapered roller bearing set to a high torque for the following reasons.

That is, the relationship between the preload and the rotation torque is as follows:
As shown in FIG. 3, when the rotational torque is set to a high range indicated by, for example, a to b in the figure, the rotational torque characteristic having a high gradient is clearly higher than the rotational torque characteristic having a low gradient.
Another variation width of the preload applied to the tapered roller bearing can be small, it requires a small preload value. If the variation width of the preload applied to the tapered roller bearing is large, the seizure life in actual use will vary, and if the preload load value is set to be large, the seizure life of the tapered roller bearing will be shortened.

In the above-described conventional tapered roller bearing with a reduced torque, the surface speed of the tapered roller guide surface is small and the interval between minute irregularities is small. , The variation in the rotational torque value increases. That is, when the rotation speed is 20 to 60 rpm, the rotation torque value is the smallest, and the rotation torque value is large in a predetermined rotation speed region before and after the rotation speed. This is considered to be because boundary lubrication is performed in a rotation speed region lower than the rotation speed region where the rotation torque value is the smallest, and fluid lubrication is performed in a rotation speed region where the rotation torque value is high. This phenomenon does not change simply when the surface roughness of the roller guide surface is made larger than the current polished surface roughness or approaches the roller end surface roughness.

The rotational speed at the time of assembling the above-mentioned differential is set at 50 to 200 rpm. However, since this assembling rotational speed includes an unstable lubricating region where the boundary lubrication changes to fluid lubrication, so-called stick slip is performed. As a result, a change in the rotational torque is large and normal assembly cannot be performed.

[0007] The present invention has been made in view of such circumstances, and has an object to enable normal assembly when used in a special device (differential or the like).

[0008]

In order to achieve the above object, the present invention provides a tapered roller bearing having a radially outwardly extending flange at one axial end of an inner ring. Take the configuration.

In the tapered roller bearing of the present invention , the surface roughness of the tapered roller guide surface of the flange of the inner ring is 1.5 to 2.5.
It is desirable to set it to μm [Rz].

[0010]

[0011]

[Function] When paper wrapping or the like is performed, the distance between the fine irregularities on this processed surface becomes wider than that of the surface polished in the past, so that the tapered roller guide surface and the end surface of the tapered roller slide. Even if it is moved, it is less likely to be familiar at the beginning of operation as in the case of the polished surface. In other words, in the case of the machined surface of the present invention, a stable lubrication state is obtained from the beginning of operation,
The rotation torque value can be set higher than in the conventional case where the polishing is performed, and the variation in the height is reduced.

Therefore, when the tapered roller bearing of the present invention is used for a differential, for example, the stick slip phenomenon does not occur in the rotation speed range at the time of assembly.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.

FIGS. 1 and 2 show an embodiment of the present invention. FIG. 1 shows the upper half of a tapered roller bearing.
Is an outer ring, 2 is an inner ring, 3 is a tapered roller, and 4 is a retainer.
The inner diameter of the outer ring 1 is gradually reduced from one axial direction to the other, and the outer diameter of the inner ring 2 is gradually increased from one axial direction to the other. A flange portion 5 extending radially outward is formed on the outer diameter surface of the large-diameter portion of the inner ring 2, and the inner side surface 6 of the flange portion 5 of the tapered roller 3 during rolling of the tapered roller 3 is formed. A tapered roller guide surface for slidingly guiding the large end surface 7 is provided. Raceway surfaces of the inner and outer rings, the roller rolling run surface superfinishing processing is given, the roughness of the roller end face is 0.5 to 0.7
μm [Rz].

The tapered roller guide surface 6 is subjected to a paper wrapping process, and the surface state of the tapered roller guiding surface 6 is such that the distance between the fine irregularities is wider than that of the surface polished. For this reason, in the tapered roller guide surface 6 formed by paper wrapping,
Adaptation during operation is unlikely to occur, and roughness remains to some extent. Therefore, since the lubrication mode remains in a stable lubrication state from the start of operation and does not result in unstable boundary lubrication, the rotational torque is stabilized to be substantially constant, for example, as shown in FIG. That is, the rotation torque does not decrease due to the adaptation. FIG. 2 shows that the surface roughness of the tapered roller guide surface 6 is 1.5 to
An example in the case of 2.5 μm [Rz] is shown. The numerical value of the surface roughness represents the height of the fine irregularities, and even if the numerical value of the surface roughness is the same as that of the paper wrapping and polishing, the interval between the fine irregularities when the paper wrapping is performed is , Because it is wider than that of the polished surface,
On the surface that has been subjected to the paper wrapping process, it is unlikely that the surface will be adapted to use.

[0016]

As described above, in the present invention, since the tapered roller guide surface is subjected to the paper wrapping process, the distance between the fine irregularities can be increased as compared with the conventional polished surface. Therefore, even when the tapered roller guide surface and the end surface of the tapered roller are slid, the running-in becomes less likely to occur in the initial operation as in the case of the polished surface, in other words, in the case of the processed surface of the present invention, As a result, a stable lubrication state can be obtained, and the rotational torque can be set higher than in the conventional case where polishing has been performed, and variations in the level can be reduced.

Therefore, when the tapered roller bearing of the present invention is used for a differential, for example, the stick slip phenomenon does not occur in the rotation speed range during assembly, and normal assembly can be realized.

[Brief description of the drawings]

FIG. 1 is a vertical side view showing an upper half of a tapered roller bearing according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a relationship between a rotation torque and a rotation speed in the embodiment.

FIG. 3 is an explanatory diagram showing a relationship between a preload and a rotational torque applied to a tapered roller bearing.

FIG. 4 is an explanatory diagram showing the relationship between the rotational speed and the rotational torque of the tapered roller bearing.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Outer ring 2 Inner ring 3 Tapered roller 4 Cage 5 Flange 6 Flanged tapered roller guide surface

Claims (1)

(57) [Scope of request for utility model registration] 1. A tapered roller bearing provided with a flange extending radially outward at one axial end of an inner ring, wherein a surface roughness of a tapered roller guide surface of the flange is 1.5 to 2.5 μm.
m [Rz], wherein the tapered roller bearing is set to m [Rz] .