JP7178180B2 - tapered roller bearing - Google Patents

Description

This invention relates to tapered roller bearings.

In general, tapered roller bearings are designed so that the raceway surfaces of the inner and outer rings and the vertexes of the tapered roller side surfaces intersect at one point on the center line of the bearing. The large end face is pressed against and guided by the inner ring large rib by the resultant force received from the inner ring.

Such tapered roller bearings are single-row or double-row (e.g., double-row) so as to withstand radial load, axial load, or their combined load. used for

The tapered rollers have a circular recessed area at the center of the end face and are rotatably held in the pocket of the cage. There is a slight gap between them to facilitate sliding contact with the rotating rollers.

For this reason, as shown in FIG. 4, when an external load such as a radial load or a moment load that bends the rotating shaft at an angle is applied to the rotating tapered roller bearing, the upper raceway surface 2a of the inner ring 2 will be deformed. , the small diameter side 3g or the large diameter side 3h of the tapered rollers 3 rotating at the position of may roll in a state of being tilted in a twisting direction with respect to the rotating shaft 2g (hereinafter referred to as a "skew" state).

When the end face of the tapered roller rotating in such an unstable state comes into contact with the inner ring large rib surface 2b, the edge (corner) of the rib may come into contact with the end face of the roller. In some cases, wear and damage called "galling" may occur due to lack of oil film.

As a measure to stabilize the posture of the tapered rollers to prevent skew, crowning is applied to one or both of the small rib surface of the inner ring and the small diameter side end surface of the tapered rollers to suppress edge contact and prevent wear and galling. Means for preventing such damage are known (Patent Document 1, Patent Document 2).

The problem of abnormal contact between the tapered rollers and the inner ring due to the skew or tilt of the tapered rollers is not limited to the small diameter side of the tapered rollers. The small-diameter side of the tapered roller that contacts the inner ring is less frequently used as a guide surface than the large-diameter side.

As shown in FIG. 5, one of the reasons why edge contact often occurs on the large diameter side is that the large end face 3a, which is the end face of the roller on the large diameter side, is formed with a recessed circular concave portion 3j. The boundary between the large end face 3a and the recessed portion 3j is formed by an angular edge (that is, edge portion) 3c. This is because the large end face is pressed against and guided by the inner ring large rib face.

A curved flank is provided on the large flange surface to form a wedge-shaped gap so that the large end face of the tapered roller in a skewed state is not damaged. It is known to supply lubricating oil to the wedge-shaped gap by positioning it in the vicinity of (Patent Document 3).

In addition, flanks are formed on both radially outer and inner sides of the sliding contact portion between the large end surface of the tapered roller and the large rib of the inner ring of the tapered roller bearing so as to escape in a direction away from the large end surface of the tapered roller, It is known that the flank and the chamfered portion of the large rib are connected by a gentle R surface to stabilize the rotational torque (Patent Document 4).

JP-A-10-184698 JP-A-4-331813 Japanese Patent Application Laid-Open No. 2000-170775 (Fig. 3, paragraph [0018], etc.) Japanese Utility Model Laid-Open No. 5-87330

However, in the above-described conventional tapered roller bearing, it was difficult to sufficiently prevent edge contact between the large end surface of the tapered roller and the boundary edge of the recessed portion with the inner ring large rib surface.
This is because, even if flanks are formed on both the radially outer and inner sides of the sliding contact portion between the tapered roller big end face and the inner ring large rib, the flank face will escape in the direction away from the tapered roller big end face. This is because a square edge is always formed at the boundary between the recessed portion and the recessed portion due to the manufacturing process.

Therefore, there is a possibility that the inner ring large rib may be worn and damaged by the edge portion of the boundary between the large end face of the tapered roller and the relief portion from the beginning of use.

Accordingly, an object of the present invention is to solve the above-described problems, prevent edge contact between the recessed portion of the large end surface of the tapered roller and the large rib surface of the inner ring, and use it for the large end surface of the tapered roller and the large rib surface of the inner ring. To provide a tapered roller bearing excellent in durability by preventing damage such as wear and galling that tends to occur from the initial stage.

In order to solve the above problems, the present invention provides an outer ring having a tapered raceway surface, an inner ring having a large rib surface on the large diameter side of the tapered raceway surface, an outer ring raceway surface and an inner ring raceway surface. In a tapered roller bearing comprising a plurality of tapered rollers arranged between and a retainer for rotatably retaining the tapered rollers, a relief portion having a predetermined diameter is formed in the center of the large end face of the tapered roller, and this diameter is A sliding contact portion with the large rib surface is provided in the outer annular region, a chamfered portion is provided at the intersection edge between the large rib surface and the outer peripheral surface of the large rib, and a smooth boundary is provided between the chamfered portion and the large rib surface. A tapered roller bearing with a flank was used.

In the tapered roller bearing of the present invention constructed as described above, a relief portion having a predetermined diameter is formed at the center of the large end surface of the tapered roller. As a result, a sliding contact portion with the large flange surface is provided in the annular region outside this diameter.
Therefore, the edge of the boundary between the large end face of the tapered roller and the relief portion does not come into contact with the sliding contact portion of the inner ring large rib surface, thereby avoiding wear and damage due to edge contact with the inner ring large rib surface. .

In addition, a chamfered portion is provided at the intersection edge of the inner ring large rib surface and the large rib outer peripheral surface, and the boundary between this chamfered portion and the large rib surface is connected by a smooth flank, so that the tapered roller bearing rotates. Even when the roller rotates in a "tilt" or "skew" state, the large end surfaces of the tapered rollers and the large rib surface of the inner ring do not come into contact with each other, thereby preventing wear and damage.

The above-mentioned smooth flank is formed by an arc surface that connects the large rib surface and the chamfered portion, so that the circular or elliptical sliding contact portion between the large end surface and the large rib surface of the tapered roller is smooth. , a wedge-shaped gap is formed.
The lubricating oil or lubricating grease normally present in the bearing flows into the wedge-shaped gap by capillary action so as to be repeatedly sucked and discharged. As a result, damage due to wear and galling due to insufficient lubrication of the sliding contact portion is also prevented.

In order to adjust the size of such a wedge-shaped gap, it is preferable that the flank face has a clearance amount of 0.010 to 0.050 mm away from the large flange face. If the escape amount is less than the above predetermined range, the effect of preventing edge contact may not be sufficient, and since lubricating oil or lubricating grease flows into the wedge-shaped gap with a small volume, the amount of inflow and discharge is reduced. On the other hand, if the relief amount exceeds the above-mentioned predetermined range, the area of the large rib surface that can contact the large end surface of the tapered roller becomes small, and the contact stress of the sliding contact portion becomes excessive, which may lead to premature damage. Also, it may not be possible to sufficiently flow lubricating oil or lubricating grease.

In addition, if the large end face of the tapered roller is a crowning type large end face that has a mid-height portion closer to the recessed portion, edge contact with the large rib surface of the inner ring is less likely to occur even if the tapered roller is in a "tilted" state. preferable.

Further, since the large end surfaces of the tapered rollers are crowned large end surfaces, the shape of the portion in sliding contact with the inner ring large rib surface is circular or elliptical, and a wedge-shaped gap is formed around the entire periphery. Therefore, the lubricating oil or lubricating grease flows in and out of the wedge-shaped gap, and damage due to wear and galling due to insufficient lubrication of the sliding contact portion is more sufficiently prevented.

In the tapered roller bearing of the present invention, a relief portion having a predetermined diameter is formed at the center of the large end surface of the tapered roller, and the relief portion is provided radially outside the outer peripheral surface of the large rib. The edge portion of the boundary edge of the large rib surface does not contact the sliding contact portion with the inner ring large rib surface, and the chamfered portion provided at the intersection edge of the large rib surface and the large rib outer peripheral surface and the large rib surface Even when the rotating tapered roller bearing rotates in a "tilt" or "skew" state, the tapered roller large end face and the inner ring large rib face do not cause edge contact because they are connected by a smooth flank face.

Therefore, the large end faces of the tapered rollers and the large rib of the inner ring are prevented from being easily damaged from the initial stage of use, such as wear and galling, and there is an advantage that the tapered roller bearing is excellent in durability.

1 is an enlarged cross-sectional view of a main portion of a tapered roller bearing according to an embodiment of the present invention; 1 is a cross-sectional view of a tapered roller bearing according to an embodiment of the present invention; Partial enlarged sectional view of FIG. Explanatory diagram showing the posture of tapered rollers on the inner ring of a conventional tapered roller bearing Enlarged cross-sectional view of the main part of a conventional tapered roller bearing

An embodiment of the present invention will be described below with reference to the accompanying drawings.
As shown in FIGS. 1 to 3, the tapered roller bearing of the embodiment has an outer ring 1 having a tapered raceway surface 1a and a large rib surface 2b formed on the large diameter side of the tapered raceway surface 2a via _an inner ring recess 2a1. tapered rollers 3 arranged between the inner ring 2 and the raceway surface 1a of the outer ring 1 and the raceway surface 2a of the inner ring 2; and a retainer 4 for freely holding it.

A relief portion 3b having a predetermined diameter 2r is formed in the center of the large end surface 3a of the tapered roller 3, and a sliding contact portion S with the large rib surface 2b is provided in an annular region radially outside the diameter 2r.

Further, as shown in FIG. 3, a chamfered portion 2d is provided at the intersection edge of the large rib surface 2b and the large rib outer peripheral surface 2c, and the boundary between the chamfered portion 2d and the large rib surface 2b is formed by a smooth flank 2e. , the conventional edge indicated by the dashed line in the figure is removed.

The relief portion 3b of the circular recessed area is formed by molding or turning the central portion of the large end surface 3a of the tapered roller 3 into a shallow tapered hole. The diameter 2r of the relief portion 3b is set to an optimum diameter so as to secure a sufficient contact area with the large rib surface 2b, thereby forming a predetermined flat or curved annular area outside the relief portion 3b. A width is secured to provide a sliding contact portion S with the large flange surface 2b.

The edge portion 3c formed at the boundary edge between the large end face 3a of the tapered roller 3 and the relief portion 3b of the circular recessed area is provided for smooth insertion and removal of the mold during molding, or for inserting and removing tools during turning. For ease, it is formed with somewhat angular edges (on the order of 90° to 150°).

The radial width of the outer annular region of the recessed portion 3b on the large end face 3a of the tapered roller 3 is set to a width equal to or greater than the width of the sliding contact portion S, and the edge portion 3c is the large rib of the inner ring. Since the diameter 2r of the relief portion 3b is set so as to be arranged radially outward of the outer peripheral surface 2c, even in the "tilt" state indicated by the chain double-dashed lines in FIGS. , the flank 2e and the chamfered portion 2d are not in contact with the edge portion 3c.

_The chamfered portion 2d at the intersection edge of the large rib surface 2b and the large rib outer peripheral surface 2c shown in FIG. A flank 2e formed by an arcuate surface with a radius of _R2 is provided to smoothly connect these boundary areas.

In this way, among the edges formed on both sides in the radial direction when only the chamfered portion 2d was initially formed, the edge ( ) disappears, and is smoothly continued by the flank 2e formed of an arcuate surface with a radius of curvature _R2 .

With such a flank 2e, even when the rotating tapered roller bearing rotates in a "tilt" or "skew" state, the large end surface 3a of the tapered roller 3 and the large rib surface 2b of the inner ring 2 are prevented from being worn. No damaging "edge hits" occur. Moreover, the flank 2e facilitates the flow of lubricating oil or lubricating grease between the large end surface 3a of the tapered roller 3 and the large rib surface 2b of the inner ring 2, thereby preventing damage such as wear. .

It is preferable that the flank face 2e having no "edge contact" is a flank face having a relief amount d separated from the large flange face 2b by 0.010 to 0.050 mm. By providing the flank with a predetermined relief amount d, the lubricating oil or lubricating grease that normally exists in the bearing flows into the wedge-shaped gap in such a way that it is repeatedly sucked and discharged by capillary action, lubricating the sliding contact parts. becomes sufficient, and damage due to wear and galling due to insufficient lubrication can be prevented.

The illustrated flank 2e is formed by a single arc surface (curvature radius R ₂ ), but may be formed by combining a plurality of arcs or by combining elliptical shapes to form a well-known smooth circular curved surface. may be

Lubricating oil or lubricating grease used in the embodiments can be used without particular limitation to those normally enclosed in rolling bearings. Incidentally, examples of lubricating oils include mineral oils such as paraffinic mineral oils and naphthenic mineral oils, hydrocarbon synthetic oils such as polybutene oils and poly-α-olefin oils, polyphenyl ether oils, alkyldiphenyl ether oils, fluorinated oils, and the like. and non-hydrocarbon synthetic oils.

As for the lubricating grease, similarly to the above, any grease that is normally used by filling rolling bearings can be used without particular limitation, and the base oil constituting the grease includes the same lubricating oil as described above. Examples of thickeners include metallic soap-based thickeners such as aluminum soap and lithium soap, urea compounds such as diurea compounds and polyurea compounds, and fluororesin powders such as PTFE resin.

Further, although the large end face 3a of the tapered roller described above has a chamfer 3f on the outer peripheral edge and the surface other than the chamfer 3f is flat, the large end face 3a is close to the recessed portion 3b. The large end face may have a crowning shape with a convex portion.

Due to the crowned big end face, a wedge-shaped gap is formed around the entire circumference of the circular or elliptical sliding contact portion S between the big end face 3a and the inner ring large rib face 2b. Lubricating oil or lubricating grease flows into or out of this wedge-shaped gap when the rotating tapered roller bearing rotates in a "tilt" or "skew" state. Damage due to wear and galling is better prevented.

1 Outer rings 1a, 2a Raceway surface 2 Inner ring 2a ₁ Inner ring recess 2b Large rib surface 2c Large rib outer peripheral surface 2d Chamfered portion 2e Flank surface 2g Rotating shaft 3 Tapered roller 3a Large end surface 3b, 3j Relief portion 3c Edge portion 3f Chamfer 3g Small diameter side 3h large diameter side 3i rotating shaft 4 retainer S sliding contact portion

Claims (4)

an outer ring having a tapered raceway surface;
an inner ring having a large rib surface on the large diameter side of the tapered raceway surface;
a plurality of tapered rollers arranged between the raceway surface of the outer ring and the raceway surface of the inner ring;
a cage that rotatably holds the tapered rollers,
A recessed portion having a predetermined diameter is formed in the center of the large end face of the tapered roller, and the edge portion of the recessed portion is arranged radially outside the outer peripheral surface of the large rib, and is formed in the annular region outside the predetermined diameter. A sliding contact portion with the large rib surface is provided, a chamfered portion is provided at the intersection edge between the large rib surface and the large rib outer peripheral surface, a smooth flank is provided at the boundary between the chamfered portion and the large rib surface, and this A tapered roller bearing in which the boundary area between the flank and the chamfer is smoothly continuous . 2. A tapered roller bearing according to claim 1, wherein said smooth flank is formed by an arcuate surface connecting the large rib surface and the chamfered portion. 3. The tapered roller bearing according to claim 1, wherein the flank has a relief amount of 0.010 to 0.050 mm away from the large rib surface. A tapered roller bearing according to any one of claims 1 to 3, wherein the large end face of said tapered roller is a crowning type large end face which is more convex toward the relief portion.

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