JP6722217B2 - Tapered roller bearing - Google Patents

Description

INDUSTRIAL APPLICABILITY The present invention is a tapered roller bearing used in a speed reducer of a robot or a construction machine, and in particular, a tapered roller bearing used for applications requiring high load capacity, high rigidity and compactness under the condition that a high moment load is applied. Regarding roller bearings.

As a tapered roller bearing used for this type of application where high load capacity, high rigidity and compactness are required, only the large diameter side end of the inner ring has a large outside diameter in the radial direction. Patent Document 1, Patent Document 2, and Patent Document 1, which provide a flange portion projecting toward one side, eliminate the small flange at the small diameter side end of the inner ring, and lengthen the roller length by the amount of the small flange to achieve high load capacity. It is disclosed in Reference 3.

The tapered roller bearings of Patent Document 1 and Patent Document 2 are provided with a small-diameter-side protruding portion that projects in the axial direction on the small-diameter side of the inner ring.

Further, the tapered roller bearings of Patent Documents 2 and 3 have a contact angle of a steep gradient of 35° to 55° to obtain high moment rigidity.

JP, 2007-32679, A JP, 2016-8641, A International publication number WO2014/104132

As shown in FIGS. 4 and 5, the tapered roller bearing 1 disclosed in Patent Document 2 or Patent Document 3 has a steep contact angle α of 35° to 55° and an outer ring raceway on the inner peripheral surface. An outer ring 2 having a surface 2a, an inner ring 3 having an inner ring raceway surface 3a on an outer peripheral surface, and a plurality of tapered rollers 4 rotatably arranged between the outer ring raceway surface 2a and the inner ring raceway surface 3a, A cage 10 having a plurality of pockets P for accommodating and holding the plurality of tapered rollers 4 at predetermined intervals is provided, and only the large diameter side end portion of the large diameter side end portion and the small diameter side end portion of the inner ring 3 is provided. A flange portion 3b protruding outward in the radial direction is provided to eliminate the small flange on the small diameter side end portion of the inner ring 3 and to lengthen the tapered roller 4 by the amount of the small flange to achieve a high load capacity.

The cage 10 accommodates and holds the large-diameter ring portion 10a and the small-diameter ring portion 10b axially separated from each other, and the tapered rollers 4 provided at a predetermined interval between the large-diameter ring portion 10a and the small-diameter ring portion 10b. And a pillar portion 10c for partitioning the plurality of pockets P.
By the way, in consideration of the compactness of the tapered roller bearing 1, when the cross section (the dimension H and the dimension T) of the tapered roller bearing 1 is made small, between the column portion 10c of the cage 10 and the outer ring raceway surface 2a of the outer ring 2. In order to secure the clearance d and the clearance c between the pillar portion 10c of the cage 10 and the inner ring raceway surface 3a of the inner ring 3, it is necessary to narrow the width e of the pillar portion 10c of the cage 10.

However, even if the width e of the column portion 10c of the cage 10 is narrowed, there is a limit in terms of manufacturing limit and strength of the cage 10, and thus there is a limit in the cage 10 during rotation of the tapered roller bearing 1. When the whirling amount becomes larger than the gap d and the gap c, the cage 10 comes into contact with the outer ring raceway surface 2a of the outer ring 2 and the inner ring raceway surface 3a of the inner ring 3 to cause the outer ring raceway surface 2a of the outer ring 2 and the inner ring 3 to move. The inner ring raceway surface 3a may be damaged or worn, causing abnormalities such as vibration when the tapered rollers 4 roll.

There is

Further, in the tapered roller bearing 1 having a steep slope of the contact angle α of 35° to 55° in Patent Document 3, considering the compactness, the following size regulation is performed.

1. The ratio of roller length Lw and inner ring width B is 0.8<Lw/B<1.2
2. 0 when inner ring inner diameter d, inner ring outer diameter D1 and inner ring large flange side height is (D1-d)/2
． 7<(D1-d)/2H<0.9
3. The ratio of the radial cross-section wall thickness H to the inner diameter d is 0.05<H/d<0.15
4. The ratio of the roller large diameter Dw1 to the radial cross-section wall thickness H is 0.3<Dw1/H<0.6.

In the tapered roller bearing 1 having such dimensions, when the minimum thickness of the inner ring 3 becomes very thin and the radial load applied to the rolling bearing 1 becomes large, the tapered roller 4 rolls on the inner ring 3 raceway surface 3a. 3 is deformed, and the fitting surface with the shaft fitted into the shaft hole of the inner ring 3 has a wavy behavior, so that creep occurs.

As described above, in the tapered roller bearing 1, if the compactness, the steep gradient of the contact angle α, and the increase of the load capacity are achieved, the thickness of the inner ring 3 becomes thin, and the fitting surface immediately below the tapered roller 4 is deformed to cause creep. Occurs.

When the small diameter side protruding portion 11 that protrudes in the axial direction is provided on the small diameter side of the inner ring 3 as in Patent Document 2, it is considered to be effective in preventing deformation of the fitting surface directly below the tapered roller 4, but what kind of Patent Document 2 does not disclose at all whether it is effective in the occurrence of creep if it is defined by the dimensional relationship.

Generally, as measures against creep, "increasing the wall thickness of the inner ring 3", "decreasing the number of tapered rollers 4", and "increasing the amount of interference fit" can be mentioned.

However, if the thickness of the inner ring 3 is increased, the compactness is deteriorated, and if the number of the tapered rollers 4 is reduced, the load capacity is reduced.

Further, if the amount of interference with the shaft is increased, the inner ring 3 has a small wall thickness, which may increase hoop stress and cause ring cracking.

Therefore, the present invention prevents the cage from coming into contact with the outer ring raceway surface of the outer ring or the inner ring raceway surface of the inner ring, so that the cage may be scratched or worn due to contact with the outer ring raceway surface of the outer ring or the inner ring raceway surface of the inner ring. It is an object of the present invention to provide a tapered roller bearing which can prevent the occurrence of creep and suppress the occurrence of creep due to the deformation of the fitting surface immediately below the tapered roller.

In order to solve the above-mentioned problems, the present invention provides 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 rolling between the outer ring raceway surface and the inner ring raceway surface. A plurality of tapered rollers arranged movably and a cage having a plurality of pockets for accommodating and holding the plurality of tapered rollers at a predetermined interval are provided, and among the large diameter side end portion and the small diameter side end portion of the inner ring, , A flange portion protruding radially outward only at the large diameter side end, and a small diameter side protruding portion axially protruding is provided on the small diameter side of the inner ring, and the outer diameter of the small diameter side protruding portion is Of the inner ring raceway surface is located on the inner diameter side with respect to the outer diameter of the small-diameter side end portion, the end surface of the small-diameter side projecting portion projects to the smaller diameter side than the small-diameter side end surface of the cage, and the contact angle is 35° or more. In a tapered roller bearing having a high contact angle, the cage has a large-diameter ring portion and a small-diameter ring portion that are axially separated, and a tapered cone provided between the large-diameter ring portion and the small-diameter ring portion at a predetermined interval. A small-diameter ring, which includes a pillar portion defining a plurality of pockets for accommodating and holding the rollers, Each of the gaps between the inner peripheral surface of the portion and the outer diameter surface of the small-diameter-side protruding portion of the inner ring is smaller than the gap between the column portion and the inner ring raceway surface of the inner ring.

A gap between the inner peripheral surface of the large diameter ring portion and the outer diameter surface of the collar portion at the large diameter end of the inner ring, and the inner peripheral surface of the small diameter ring portion and the outer diameter surface of the small diameter side protrusion of the inner ring. The gap between and may be the same.

A grease reservoir groove may be provided at the joint between the inner ring raceway surface of the inner ring and the small-diameter side protrusion.

By defining the axial dimension of the inner diameter surface of the inner ring so as to satisfy the following equation, it is possible to suppress the occurrence of creep due to the deformation of the fitting surface immediately below the tapered roller.
Q+P>0.7Lw×cos α
Q>P
T>Q+P+0.7Lw×cos α
However, P is the major flange axial dimension, Lw x cos α is the axial dimension immediately below the tapered roller, Lw is the tapered roller length, Q is the axial dimension of the small diameter side protrusion, and T is the axial dimension of the tapered roller bearing. is there.

As described above, according to the present invention, even if the whirling amount of the cage increases during rotation of the tapered roller bearing, the cage does not contact the outer ring raceway surface of the outer ring or the inner ring raceway surface of the inner ring. It is possible to prevent the occurrence of scratches and wear due to the cage contacting the outer ring raceway surface of the inner ring and the inner ring raceway surface of the inner ring, and to suppress the occurrence of creep due to the deformation of the fitting surface immediately below the tapered rollers. ..

FIG. 3 is a partial cross-sectional view of the tapered roller bearing of the present invention cut by a column portion of a cage. It is a fragmentary sectional view which cut|disconnected the assembly state of the tapered roller bearing of this invention at the center of the pocket of a holder. It is a figure which shows a tapered roller. FIG. 9 is a partial cross-sectional view of the tapered roller bearing of Patent Document 2 taken along a column portion of a cage. FIG. 10 is a partial cross-sectional view of the tapered roller bearing of Patent Document 3 taken along a column portion of a cage.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
The tapered roller bearing 11 according to the present invention has a steep contact angle α of 35° or more, and the tapered roller bearing 11 of the embodiment shown in FIGS. 1 and 2 has a contact angle α of 45°.

A tapered roller bearing 11 according to the present invention includes an outer ring 12 having an outer ring raceway surface 12a on an inner peripheral surface, an inner ring 13 having an inner ring raceway surface 13a on an outer peripheral surface, the outer ring raceway surface 12a and the inner ring raceway surface 13a. A plurality of tapered rollers 14 rotatably arranged therebetween and a cage 20 having a plurality of pockets P for accommodating and holding the plurality of tapered rollers 14 at predetermined intervals are provided. Of the section and the small-diameter side end, only the large-diameter side end has the flange 13b protruding outward in the radial direction.

The inner diameter of the inner ring 13 is provided with a small diameter side protruding portion 13c protruding in the axial direction.

The outer diameter D ₁ of the small diameter side protruding portion 13c is located on the inner diameter side of the outer diameter D ₂ of the small diameter side end portion of the inner ring raceway surface 13a of the inner ring 13, and the end surface 13e of the small diameter side protruding portion 13c is retained. It projects toward the smaller diameter side than the end surface 20d on the smaller diameter side of the container 20.

The outer diameter surface 13d of the small diameter side protruding portion 13c is formed in parallel with the axis of the inner ring 13.

As described above, when the small-diameter side end portion of the inner ring 13 is provided with the small-diameter side projecting portion 13c that projects to the smaller diameter side than the small-diameter side end surface 20d of the retainer 20, the outer ring 12 is shown in FIG. As described above, by fitting the ring spacer 21 that abuts the end surface 13e of the small-diameter-side protruding portion 13c of the inner ring 13 on the inner peripheral surface of the outer ring 12 on the small-diameter side, the wobbling of the outer ring 12 with a high contact angle can be prevented. Since it can be suppressed by 21, the outer ring 12 is stabilized, and the assembly width dimension T of the bearing can be accurately measured.

The cage 20 accommodates and holds the large-diameter ring portion 20a and the small-diameter ring portion 20b axially separated from each other, and the tapered rollers 14 provided at a predetermined interval between the large-diameter ring portion 20a and the small-diameter ring portion 20b. And a pillar portion 20c for partitioning the plurality of pockets P.

In the present invention, as shown in FIG. 1, the gap a between the inner peripheral surface of the small diameter ring portion 20b of the cage 20 and the outer diameter surface of the small diameter side protruding portion 13c of the inner ring 13 and the large diameter of the cage 20. The gap b between the inner peripheral surface of the ring portion 20a and the outer diameter surface of the collar portion 13b at the large diameter side end portion of the inner ring 13 is set so that the column portion 20c of the cage 10 and the inner ring raceway surface 13a of the inner ring 13 and the outer ring 12 are formed. The clearances c and d between the outer ring raceway surface 12a of the outer ring 12 and the outer ring raceway surface 12a of the retainer 10 are made smaller before contact with the outer ring raceway surface 12a of the outer ring 12 and the inner ring raceway surface 13a of the inner ring 13. Both ends of 20 contact the outer diameter surface of the collar portion 13b at the large diameter end of the inner ring 13 and the outer diameter surface of the small diameter side protrusion 13c of the inner ring 13, and the outer ring raceway surface 12a of the outer ring 12 is guided by this contact. The inner ring raceway surface 13a of the inner ring 13 is prevented from being damaged.

The specific relationship between the gaps c, d, a, and b is c, d>a=b.

Further, in order to facilitate the management of the clearances a and b, the outer diameter surface of the small diameter side protruding portion 13c of the inner ring 13 and the outer diameter surface of the flange portion 13b at the large diameter side end portion of the inner ring 13 are parallel to each other in the axial direction. Is desirable.

Further, since both ends of the cage 20 can be supported with respect to the inner ring 13 by making the gaps a and b both have the same width, the moment load applied to the cage 20 can be reduced as compared with the case where the cage 20 is supported on one side. You can

A grease reservoir groove 13f is formed at the joint between the inner raceway surface 13a of the inner race 13 and the small diameter side protrusion 13c. When grease lubrication is adopted, by accumulating grease in the grease reservoir groove 13f, it is possible to reduce poor lubrication on the small diameter side of the inner ring raceway surface 13a of the inner ring 13.

Further, when the grease reservoir groove 13f is provided at the joint between the inner ring raceway surface 13a of the inner ring 13 and the small diameter side protruding portion 13c, when the tapered roller bearing 11 is erected in the vertical direction, the tapered portion of the tapered roller 14 on the small diameter side is Since the taper roller 4 can be held by being caught in the grease reservoir groove 13f, the grease reservoir groove 13f functions as a small flange for holding the tapered roller 4.

Next, the inventor of the present invention has made the relationship between the axial dimension of the inner diameter surface of the inner ring 13, that is, the large flange axial dimension P, the axial dimension (Lw×cos α) immediately below the tapered roller 14, and the small diameter side protrusion. It has been found that the occurrence of creep can be suppressed by defining the relationship of the axial dimension Q of the portion 13c as follows.

What is that relationship?
Q+P>0.7Lw×cos α
Q>(0.7Lw×cos α)-P
Q>P
T>Q+P+0.7Lw×cos α
Is.

It was verified under the following conditions that the occurrence of creep can be suppressed by the above relational expression.
-Fit with shaft: k6 to m6 for radial bearings (JIS0 class) (for example, if the inner diameter is φ240, the fit interference is 4um to 71um)
・Maximum contact surface pressure between rolling element and inner ring raceway 2 patterns: 1500 MPa, 2500 MPa

The verification results are shown in Table 1, and on the inner diameter surface of the inner ring 13, a width dimension (Q+P) immediately below the non-rolling element that is 0.7 times or more of the axial width dimension (Lw×cos α) immediately below the rolling element is If so, creep can be suppressed.

The present invention is not limited to the embodiments described above, and it is needless to say that the present invention can be implemented in various forms without departing from the scope of the present invention. And the equivalent meanings recited in the claims, and all changes within the scope.

10: Cage 11: Bearing 12: Outer ring 12a: Outer ring raceway surface 13: Inner ring 13a: Inner ring raceway surface 13b: Collar part 13c: Small diameter side protrusion 13d: Outer diameter surface 13e: End surface 13f: Grease collecting groove 20: Cage 20a: Large-diameter ring part 20b: Small-diameter ring part 20c: Column part 20d: End face 21: Ring spacer P: Pocket

Claims (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 tapered rollers rotatably arranged between the outer ring raceway surface and the inner ring raceway surface, A cage having a plurality of pockets for accommodating and holding a plurality of tapered rollers at predetermined intervals, and of the large-diameter side end and the small-diameter side end of the inner ring, only the large-diameter side end is radially outward. A projecting collar portion is provided, and a small diameter side projecting portion that projects in the axial direction is provided on the small diameter side of the inner ring, and the outer diameter of this small diameter side projecting portion is smaller than the outer diameter of the small diameter side end portion of the inner ring raceway surface of the inner ring. Is located on the inner diameter side, the end surface of the small-diameter side protruding portion projects to the smaller diameter side than the end surface on the small diameter side of the cage, and the contact angle is a high contact angle of 35° or more. A cone characterized in that the axial dimension of the surface is defined so as to satisfy the following formula, and a ring spacer that abuts against the end surface of the small-diameter side protrusion of the inner ring is fitted on the small-diameter inner peripheral surface of the outer ring. Roller bearing.
Q+P>0.7Lw×cos α
T>Q+P+0.7Lw×cos α
However, P: Large tsuba axial dimension
Q: Axial dimension of small diameter side protrusion
T: Axial dimension of tapered roller bearing
Lw x cos α: Axial dimension directly under the tapered roller
Lw: Length of tapered roller
α: contact angle

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