JPS5934018A - Multiple-row thrust conical roller bearing - Google Patents

Abstract

PURPOSE:To reduce generation of heat on the rolling contact surface of a conical roller by setting the wall thickness of an inner race of the above bearing to be of a specified thickness to the radial length extending from the inner peripheral edge of the inner race to an intersecting point of the plane of an orbit of the inner race and a generating line of the large end surface of the conical roller. CONSTITUTION:A bearing comprises an inner race formed by fitting a countershaft 1 to a rotary shaft and bringing collars 42, 43 into contact with both side end surfaces thereof to be positioned ?and fixed, and a conical roller 48 rotatably interposed between ?both side end surfaces of the inner race and the plane 45 of an orbit of an outer race 44. In this case, when the wall thickness of the inner race 41 is W, and the radial length extending from the inner peripheral edge of the inner race 41 to an intersecting point C of a plane 41a of an orbit of the inner race 41 and an extension line of a generating line of the large end surface 49 of the conical roller 48 contacting the plane of an orbit is H, the wall thickness W of the inner race 41 is se to be W/H>=0.8. The ratio Hc/H of the radial gap Hc between the inner peripheral edge of the inner race 41 and the inner peripheral edge of a retainer 51 to the contact upper limit height H of the inner race 41 should be Hc/H>=0.26.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a double-row thrust tapered roller bearing, and in particular to a thrust tapered roller bearing in which the end face of the inner ring of the bearing is fixed to the shaft via a collar, the wall thickness of the inner ring is fully regulated. By doing so, the generation of edge load and heat generation at the rolling contact surface of the tapered rollers caused by the axial deflection of the inner ring are reduced, and the thrust load capacity is greatly increased.

For example, a double-row thrust tapered roller bearing with a small volume and large thrust load capacity is suitable as a thrust bearing for the roll neck of a rolling mill. growing. In conventional double row thrust tapered roller bearings,
When such a large thrust load is applied, the load distribution between the raceway surface and the raceway surface on the tail side of the tapered roller becomes high, which not only causes edge load, but also causes abnormally high heat, which can lead to seizure accidents. It has the disadvantage that it cannot withstand long-term use.

In order to investigate the cause of this phenomenon, various experiments were repeated and it was found that it was caused by the axial deflection of the inner ring.

In other words, edge load is caused by the tail side of the tapered roller coming into strong contact with the raceway surface due to the deflection of the inner ring, and is particularly likely to occur if the crowning shape of the tapered roller is not appropriate.Heat generation is caused by the deflection of the inner ring. Because the intersection of the generatrix of the inner ring raceway surface and the outer ring raceway surface deviates from the center axis (rotation center) of the bearing, the tapered rollers that contact the raceway surface are also displaced, causing their cone centers to deviate from the center axis and roll. Especially in the evening, we come into contact with each other.

Furthermore, we investigated the causes of axial deflection of the inner ring and found that the wall thickness of conventional inner rings was thin, and the height of the end surface of the collar for positioning the inner ring was low, resulting in insufficient fixing force for the inner ring. We came to the conclusion that this is due to the fact that the situation is close to support. By the way, the conventional surface pressure at the end face of the inner ring and collar is 30 kq/mA or more, and the maximum deflection of the inner ring in this case is calculated assuming that the inner ring is freely supported, and the result is that it is 15~ It will be 40 times larger.

This invention was made in view of the above points,
An object of the present invention is to provide a thrust tapered roller bearing in which the inner ring does not substantially deflect in the axial direction even under large thrust loads;
It is an object of the present invention to provide a thrust tapered roller bearing in which edge load and heat generation at the rolling contact surface between the tapered rollers and the bearing ring are reduced.A further object of the present invention is to provide a double row thrust tapered roller bearing having a large load capacity. It's about doing.

That is, the present invention is applicable to the shaft (roll neck) 1, as in the embodiment of the illustrated rolling mill roll neck, for example.
2 between the shoulder 13 and the collar 43 or the collar 42
．． ．． Tapered rollers 48 are arranged in double rows via a retainer 51 between an inner ring 41 that is positioned and fixed between the inner ring 43 and an outer ring 44 that is fitted to the outer ring 14 and 15. A thrust tapered roller bearing 4 in which at least one of the rolling surface of the rollers 48 and the raceway surfaces 41a and 45 of the inner ring 41 and the outer ring 44 is crowned.
0, the wall thickness W of the inner ring 41 was set to be 80% or more of the radial length H from the inner peripheral edge of the inner ring 41 to the intersection of the generatrix of the raceway surface 41a and the large end surface 49 of the tapered rollers 48. The present invention relates to a double-row thrust tapered roller bearing characterized by:

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, in which reference numeral 10 is a roll of a rolling mill, 12 is a roll neck, 14.
Reference numeral 15 indicates a housing, in which a large diameter portion 12a of the roll neck 12 is supported in the radial direction by a radial tapered roller bearing 16 within the housing 14.

The radial tapered roller bearing 16 has two double-row inner rings 17.
It consists of two single-row outer rings 18, one double-row outer ring 19, and four rows of tapered rollers 20. 21 is a cage, 22 is an outer ring spacer, and 26 is an inner ring spacer. The single-row outer ring 18 is positioned in the axial direction by a presser member 25 and a presser ring 26 fitted to the housing 14. Two seals 28 are fitted to the presser member 25 through the spacer 29, and the seals 28 are fitted to the outer periphery of a fillet ring 30 fitted to the shoulder of the roll 10 and the large diameter portion 12a of the roll neck 12. The lips are in sliding contact. It's ok, presser member 25 ii%1
The seal 31 is attached to the end in one direction by a seal presser 32 (fitted tightly and slid into contact with the fillet ring 30,
A seal 33 is provided between the roller 2 and the roll 10. 6
4 is an oil supply hole, and lubricating oil is forced through this oil supply hole 34.
Let's make a ring.

The small diameter portion 121) of the roll neck 12 is provided with a thrust tapered roller bearing 40 of the present invention.

This bearing has a small diameter portion 1 of the intermediate wheel 41 and the entire roll neck 12.
2bK is inserted, and the collars 42°46 are fully abutted on both end faces of the inner ring, and the inner ring is formed by positioning and fixing.
A boxwood outer ring 44 is fitted to each of the outer rings 15 and 4.
The tapered rollers 48 are movably brought into contact between the raceway surface 45 of No. 4 and both end surfaces of the inner ring 41, and the roll neck 12
It is configured as a thrust bearing in a row of crosspieces that supports the bearing in the axial direction.

51 is a cage for holding and guiding the tapered rollers 48; 52 is a spacer for positioning the outer ring 44; the spacer 52 is provided with an oil passage hole 56; A plurality of oil drain holes 55 communicating with the oil passage hole 56 are provided.

Outer ring 44 slidingly contacts large end surface 49 of tapered roller 48 mentioned above
The guide surface (flange surface) 47 of the zero rib 46 is formed into a spherical shape, and the radius of curvature of the large end surface 49 of the tapered roller 48 is the entire outer ring 4.
The radius of curvature of the collar surface 47 of No. 4 is set in the range of 70 to 85 inches, so that the contact state between the large end surface 49 of the tapered roller 48 and the collar 47 of the outer ring 44 is good. .

In addition, the outer ring 44 has an oil supply hole 60 that opens at the boundary between the raceway surface 45 and the collar 47 (grinding part) +/'C, and a oil supply hole 62 that opens at the tail side of the raceway surface 45 (c). Multiple holes are drilled from the back side of each, and these oil supply holes 60 and 62'
The oil passages 64 provided in the housings 14 and 15 communicate with each other.

Furthermore, two seals 65 are disposed on both sides with a spacer 65 interposed between the housing 15 and the collar 43 for sealing.

The 61 slippage of the thrust bearing 40 described above is achieved by injecting lubricating oil into an oil jet from the oil supply hole 60.62 of the outer ring 44 through the oil passage 64 of the housing 14. and outer ring 44 boxwood 4
After lubricating the sliding surface between G0 and G0, and fully lubricating the contact surface between the raceway surfaces of the inner ring 41 and outer ring 44 and the transfer surface of the tapered rollers 48 through the oil supply hole 62 and circulating the inside of the bearing, the spacer 52 oil passage hole 53) and Uzing 14 oil drain hole 5
5 and is discharged to the outside.

Therefore, the thickness of the inner ring 41 in the thrust bearing 40 is set as follows. As shown in FIG.
The wall thickness is 2w, from the inner peripheral edge of the inner ring 41 to the raceway surface 41a of the inner ring 41 and the large end surface 49 of the tapered roller 48 that contacts this.
If the length in the radial direction up to the intersection point C with the extension line of the generatrix is ff I-1, then the wall thickness W is increased so that W/LT>0.8. W/LT
The upper limit of is limited by the allowable range of the assembly space of the bearing portion, but can be up to about 1.1.

The radial clearance Hc between the twisted inner circumferential edge of the inner ring 41 and the inner circumferential edge of the retainer 51 and the contact upper limit height of the inner ring 41 + (
The ratio of 1-Ic/H to Hc/H) is set to be 0.26. Regarding the upper limit value 1 of I-1c /H, [If 10 is excessively increased, the length of the tapered roller 48 will decrease for the given upper limit contact height 1-T, which will lead to a decrease in the bearing load rating. Therefore, it is necessary to select it appropriately within the allowable range of the assembly space, but it can be up to about 0.35. In this way, by increasing the radial clearance LTcQ, the height of the end surface of the positioning collars 42 and 43 of the inner ring 41 can be increased and brought into contact with both end surfaces of the inner ring 41.

As described above, by setting the dimensions of the inner ring 41 and the collars 42 and 43, the bending rigidity of the inner ring 41 itself increases, and the support of the inner ring 41 for the roll neck 121) can be made into a strong fixed support. Therefore, even if a large thrust load acts on the inner ring 41, the axial deflection of the inner ring 41 can be reduced. However, if the axial deflection can be reduced only by increasing the wall thickness W of the inner ring 41, it is not necessarily necessary to increase the end surface height of the collars 42, 43.

The inner ring 41 of the above embodiment has collars 42 and 43 on both end surfaces.
However, one collar 42 is omitted and the end surface of the inner ring 41 on the roll neck 12a side is brought into contact with the shoulder 16 of the roll neck 1'2a and fixed. It's okay.

As shown in FIG. 3, the transfer surface of the tapered roller 48 of the second I11+ receiver is rounded as shown in FIG.

Total effective length tr of tapered roller 48, head 48a and tail 4
8b, the total length tl, and the length k of the intermediate portion 48c.
72, the intermediate portion 48c has a crowning radius of curvature R2, and the head portion 48a and tail portion 48b have a radius of curvature t!
, and the generatrix of the intermediate portion 48c and the generatrix of the head portion 48a and the tail portion 48b are at their intersection A,
Let B be a circular arc having a common tangent line. The length t2 of the intermediate portion 481 is t2 with respect to the total effective length Lr.
=o, 7tr, and the radius of curvature R12 of the intermediate portion 48c is set such that R2> 3 OR+ with respect to the radius of curvature a of the head portion 48a and the tail portion 48b. in this way,
Crowning is applied to the entire transfer surface of tapered roller 48,
Moreover, by making the radius of curvature Rt' of both ends of the head 48a and tail part 48b significantly smaller than the radius of curvature R2 of the intermediate part 4'8c, it is possible to suppress the occurrence of edge load on the transfer surface of the tapered roller 48. .

The above crowning may be applied to the raceway surfaces of the inner ring and the outer ring, or may be applied to both the twisted tapered rollers and the inner ring and the outer ring.

Furthermore, in the above bearing, when the inner ring 41 is deflected in the axial direction, the intersection of the generatrix of the raceway surfaces of the inner ring and the outer ring is made to coincide with the cone center of the tapered rollers.
A so-called offset configuration is provided. That is, in the conventional bearing, when the bearing is under no load as shown in FIG. 4(a), the cone center P of the tapered rollers 48 is
1 and the intersection point I) 2 of the generatrix of the raceway surfaces 41a and 45 of the inner ring 41 and the outer ring 44 coincide with the central axis O-0 of the bearing. Assuming that the position shown is tilted by an angle θ and the generatrix of the transfer surface of the tapered roller 48 is coincident with the generatrix of the raceway surface 45 of the outer ring 44, P2 is a point P2 shifted by a distance X from the central axis O-0. position.

na-1r' tanθ Here, Ra-Length between the large end face of the tapered roller and the cone center P+ P3) Lr-Length of generatrix of the rolling surface of the tapered roller (P3 P4) 2β
- Tapered angle of tapered rollers In this way, the intersection point P2 of the cone center P1 and the raceway surface generatrix deviates from the center axis 0-0, resulting in differential slip between the rolling surface of the tapered rollers 48 and the raceway surface. will occur.

Therefore, as shown in the same figure (1)), the inner ring 41 and the outer ring 4 are
The cone center P+f of the tapered roller 48 is located on the left side of the central axis O-O at the intersection P2 of the raceway surface 41a with 4 and the generatrix of 45.
The raceway surface 41a of the inner ring 41 and the outer ring 44 is located on the right side of the fi center axis 0-0.

45 is made smaller than the conical angle 2β of the tapered rollers 48 by the angle θ of the inner ring 41, η=2.
Let β−θ.

If the distances between the cone center P1 and the intersection point P2 of the raceway surface generatrix from the center axis O-O are each 81.82, then SH: Ra ” θ ・S l n 2βS
2 = Ra ”θ(cosec(2β-θ)-8in
2β]Here, Ra"P1p3:po P3 Therefore, when the inner ring 41 of the bearing set in this way receives a thrust load and bends in the axial direction and tilts by an angle θ as shown by the broken line, the tapered rollers 48 also bend in this direction. tilted by the same angle as the cone center P, and the intersection point P2 of the raceway surface generatrix.
is the angle η formed by the generatrix of the raceway surfaces of the inner ring 41 and the outer ring 44 under load, since both coincide with the point Po on the center line 4q11 line O-0. is equal to the tapered roller 480 cone angle 2β. As a result, no differential slip occurs between the rolling surface of the tapered rollers 48 and the raceway surface.

Although it is sufficient to provide the above-mentioned offset at least at the generatrix intersection of the raceway surface and the cone center of the tapered roller, it may be omitted if necessary.

As described above, the present invention provides tapered rollers that are disposed between both end faces of the inner ring, which is positioned and fixed to the shaft via the collar', and the outer ring on the housing side, and are supported in the axis kil+ direction. For thrust tapered roller bearings in which at least one of the rolling surface of the tapered rollers and the raceway surface of the raceway ring is crowned, the thickness of the inner ring must be at least a specified value as the upper limit height for contact with the tapered rollers. Set it to
The structure increases the bending rigidity of the inner ring. Therefore, according to the invention, the allowable node u of the internal space of the bearing
Since the wall thickness of the inner ring can be set to the maximum thickness within the contact upper limit height within H, even when a large thrust load is applied, the axial deflection of the inner ring is so small that it can be virtually ignored. The load distribution between the transfer surface of the tapered rollers and the raceway surface of the bearing ring becomes equal, making it possible to prevent edge load from occurring.

Furthermore, according to this invention, since the axial deflection of the inner ring is suppressed, the intersection of the cone center of the tapered rollers and the bearing ring generatrix does not need to be offset, and even when loaded, Since there is no deviation, it is also possible to prevent heat generation due to constant friction at the contact surface between the transfer surface and the raceway surface.

Therefore, since the thrust tapered roller bearing of the present invention has a significantly increased load capacity, it can be used as the most suitable bearing for the roll neck of a rolling mill where a large thrust load is generated, for example.

[Brief explanation of drawings]

FIG. 1 is a longitudinal side view showing all the embodiments of the present invention;
The figure is an enlarged view of the main part, Figure 3 is a generatrix diagram of the transfer surface of the tapered roller of the present invention, and Figure 4 is the positional relationship between the cone center of the tapered roller and the intersection of the raceway surface generatrix of the bearing ring. Figure (a) shows a bearing without offset, Figure (1) shows a bearing without an offset.
) is a cross-sectional view of the bearing provided in Offsera 14. In the figure, 12 is the roll neck (IiIlII), 13 is the shoulder of the roll neck, 14.15 is the housing, 40 is the thrust bearing, 41 is the inner ring, 41a is the raceway surface of the inner ring, 42
．． 43 is a collar, 44 is an outer ring, 45 is a raceway surface of the outer ring, 4
8 is the tapered roller 1.49 is the thick end surface of the tapered roller, 51 is the cage, W is the tapered roller flesh +g, and +r is the radius from the inner peripheral edge of the inner ring to the intersection of the generatrix of the raceway surface and the large end surface of the tapered roller. It is the direction length. Patent Applicant: NSK Ltd. Mitsubishi Heavy Industries, Ltd. Agent: Tetsuya Mori, Patent Attorney: Yoshikazu Uchifuji, Attorney-at-Law, Yoshiaki Shimizu, Attorney-at-Law, Kiyoshi Kajiyama This is a continuation of page 1 ■Applicant: Mitsubishi Heavy Industries, Ltd. Company 2-5-1 Marunouchi, Chiyoda-ku, Tokyo

Claims (3)

[Claims] (1) An inner ring that is positioned and fixed between the shoulder of the shaft and the collar or between the collars, and the No-Ujifugu K1
A thrust cone in which tapered rollers are arranged in double rows with a cage attached between the outer ring and the tapered roller, and at least one of the rolling surface of the tapered rollers and the raceway surfaces of the inner ring and outer ring is crowned. In the roller bearing, the wall thickness of the inner ring is 80% or more of the radial length from the inner peripheral edge of the inner ring to the intersection V of the generatrix of the raceway surface and the large end surface of the tapered roller. Double row thrust tapered roller bearing. (2) A gap of 26% or more of the radial length from the inner circumferential edge of the inner ring to the intersection of the generatrix of the raceway surface and the large end surface of the tapered roller is formed between the inner circumferential edge of the inner ring and the inner circumferential edge of the cage. A double row thrust tapered roller bearing according to claim 1. (3) Crowning with different radii of curvature and whose generatrix lines share a common tangent is applied to the intermediate portion of at least one of the transfer surfaces of the tapered rollers and the raceway surfaces of the inner ring and the outer ring, and to both ends of the head side and the tail side. , Claim 1 or 2, wherein the intermediate portion is 70% of the total effective length of the tapered roller, and the radius of curvature of the intermediate portion is 30 times or more the radius of curvature of both end portions.
Double-row thrust tapered roller bearings as described in Section 2.