Support bearing, in particular running roller

Abstract

A support bearing, for example for straighteners, having an outer ring, an inner ring and rolling bodies that roll between the outer and inner ring on raceways. A bending moment prevails between the rings as a result of a load with a fixed direction of action. To compensate for the bending moment, an outer raceway of the inner ring and/or an inner raceway of the outer ring includes a profiling with a variable diameter in the axial direction. The profiling is adapted or approximated to a non-cylindrical bending line caused by the bending moment in the rolling contact, and the bending line is defined by a line, on which bending forces which are transmitted from the inner ring to the rolling bodies and are caused by the bending moment lie substantially perpendicularly. As a result, the disadvantageous edge loading in a given load direction is suppressed, with the result that more rolling bodies can transmit load between the rings at the same time.

Claims

1. A support bearing comprising an outer ring, an inner ring, and rolling bodies that roll between the outer ring and the inner ring on raceways thereof, wherein a bending moment between the rings is applied by a load with a fixed effective direction, wherein at least one of the raceway on an outer surface of the inner ring or the raceway on an inner surface of the outer ring has a profiling with a diameter (D) that changes in an axial direction, the profiling is at least approximately equal to a bending line in rolling contact caused by the bending moment and the bending line is a line that is essentially perpendicular to the bending forces transmitted by each ring to the rolling body and caused by the bending moment, and the raceway on the outer surface of the inner ring has, in an area of a load zone (L) in the circumferential direction, a smaller curvature than the raceway of the inner ring outside of the load zone (L).

2. The support bearing according to claim 1, wherein the inner ring is integrated into a solid shaft, a solid pin, or a solid axle journal, and the profiling of the raceway on the outer surface is formed on the solid shaft, the solid pin, or the solid axle journal.

3. The support bearing according to claim 1, wherein the inner ring is brought onto a shaft, pin, or axle journal and secured against torsion.

4. The support bearing according to claim 1, wherein the profiling of the raceway on the outer surface of the inner ring is defined at least in one area by a radial correction function w(x) and a diameter D(x) of the inner ring depends on w(x) and a constant diameter D.sub.0 in the following way:
D(x)=D.sub.0−2*w(x);
w(x)=R.sub.K2−R.sub.K2.sup.2−x.sup.2).sup.−0.5 where x is an axial position on the inner ring and a second radius of curvature (R.sub.K2) is selected as a function of at least one of a direction or magnitude of the bending moment.

5. The support bearing according to claim 4, wherein the second radius of curvature (R.sub.K2) is between 5000 to 30000 mm.

6. The support bearing according to claim 1, wherein the rolling bodies are arranged in two, three, or four rows of rolling bodies.

7. The support bearing according to claim 6, wherein at least four rolling bodies of a row of rolling bodies transmit an increased percentage of a support force between the outer ring and inner ring.

8. The support bearing according to claim 1, wherein the smaller curvature is defined in the circumferential direction by a first radius of curvature (R.sub.K1) that is greater by 0.2% to 0.8% of the raceway diameter (D) than a raceway radius (R).

9. A running roller comprising the support bearing according to claim 1.

10. A straightening machine comprising the support bearing according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be described and explained in more detail below with reference to the embodiments shown in the figures. Shown are:

(2) FIG. 1 a three-row support roller with cylinder rollers in longitudinal section along the rotational axis as a first embodiment,

(3) FIG. 2A a schematic illustration of a uniformly distributed support force,

(4) FIG. 2B a schematic illustration of a bending line in the presence of a bending moment,

(5) FIG. 3 a sectional view of a three-row support bearing with rotating inner ring as second embodiment,

(6) FIG. 4 an illustration of a raceway curvature in the circumferential direction with a first radius of curvature,

(7) FIG. 5 an illustration of a raceway curvature in the axial direction with rounded and cylindrical areas,

(8) FIG. 6 an inner ring on a pin of a third embodiment in three-dimensional view,

(9) FIG. 7 a two-dimensional view of the inner ring with pin from FIG. 6,

(10) FIG. 8 a fourth embodiment with needle bearings in longitudinal section, and

(11) FIG. 9 a schematic three-dimensional illustration of a pin outer surface with profiling and flattened section.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(12) FIG. 1 shows a three-row support roller with rolling bodies 1 formed as cylinder rollers in longitudinal section along the rotational axis RA. The profiled pin section 7 is increased radially in comparison to the similarly stationary pin 6, in order to carry the three rolling body rows for a larger partial circle diameter. The profiling is formed on the outer surface of the pin section 7 and changes in the axial direction, wherein the profiling overall has a convex shape that forms, in the area of the middle row of rolling bodies, the greatest diameter D=D.sub.max and has, at the edges, the smallest diameter D=D.sub.min. In the circumferential direction, the profiling does not change.

(13) The profiling continues into the load zone L. The edge wear due to the bending moment is also normally highest in the area of the load zone L, so that, in the area of the shaft bending, the axially varying profiling is especially needed. The effect of the bending moment can be advantageously compensated in this way. In addition, it is advantageous that the inner raceway of the outer ring 2 does not have to have profiling or different raceway variations, therefore there is a high degree of freedom in the design of the shape.

(14) The pin 6 is stationary and contains various holes 8, 9 that are provided for conducting oil to the rolling contact. The base rings 4, 5 provide for a correct seating of the seals 3 and prevent the axial runout of the rolling bodies 1 of the outer rows.

(15) FIG. 2A shows a schematic illustration of the ideal case for an axially uniformly distributed support force 10. Wear of the support bearing would occur uniformly, which guarantees a long service life. This situation is provided for a support force introduced purely perpendicular to the rotational axis RA and on the support bearing, wherein the bending line 15 that is defined in the cross section along the rotational axis RA also forms a straight line at each position x 13. A profiling therefore would not be necessary. The outer raceway of the inner ring could have a cylindrical shape.

(16) FIG. 2B shows a schematic illustration of a bending line 16 for an active bending moment. The correction function w(x) causes a diameter function D(x)=D.sub.0−2*w(x) increasing in the direction of the holding point 12. The associated second radius of curvature R.sub.K2 of the curvature in the axial direction can here assume values between 5000 and 30000 mm as a function of the bending line. The profiling radius is half as large as D(x) and changes as a function of the axial position x in the curved areas. In the cylindrical areas of the profiling, the profiling radius remains constant.

(17) FIG. 3 shows a three-row support bearing with rotating inner ring 23. The feed of the lubricating oil is realized through the openings 21 that are arranged between the outer ring segments 20a, 20b or the outer ring segments 20b, 20c. Each row of rolling bodies has its own cage 3 and an individual profiling 22 that takes into account the bending moment of the whole support bearing arrangement (only the support bearing is shown). In addition, the inner raceways 35a, 35b, 35c are also profiled.

(18) For simpler pressing, the shown support bearing, in particular, the support roller, has a conical area 26 on the inner ring 23.

(19) On the outer ring section 20a, an end groove 27 is formed that can be used for aligning the outer ring 20.

(20) FIG. 4 shows a rolling body raceway 20 of an inner ring with the radius R, starting from the rotational axis RA oriented perpendicular to the plane of the drawing, wherein the raceway 20 is a stationary raceway 20.

(21) The less curved area is defined by the first radius of curvature R.sub.K1 and begins or ends at the respective intersecting points with the raceway radius R, wherein the first radius of curvature R.sub.K1 is machined to the reference point B that is arranged with respect to the rotational axis RA relative to the maximum material removal F. The distance of the reference point B relative to the rotational axis RA is the eccentricity E that is formed from the sum of the radial difference and the maximum material removal F:
E=R.sub.K1−R+F

(22) With respect to FIG. 1, the raceway 20 shown in FIG. 4 involves the outer raceway of the pin section 7 of the middle row of rolling bodies or alternatively the outer raceway of the inner ring 31 of FIG. 6. The profiling cannot be identified due to the cut surface of FIG. 4 oriented perpendicular to the rotational axis RA.

(23) FIG. 5 shows a profiling in the axial direction with a cylindrical area of length L.sub.Z and with two laterally adjacent, curved areas of length L.sub.X. The second radius of curvature R.sub.K2 is referenced to point P and is shown exaggerated. The curvatures permit an approximation to the bending line of the outer two raceways 30a and 30c. The middle raceway 30b is not critical due to its position and therefore has a cylindrical design. A curvature in the axial direction can be omitted.

(24) FIGS. 6 and 7 show an embodiment of an inner ring 31 with pin 36 in a third embodiment in three-dimensional or two-dimensional view. The outer raceways 30a, b, c of the inner ring 31 are profiled in the axial direction and also have a curvature and a profiling in the load zone L that is defined by the main direction of the support force R.sub.H. Interestingly, the pin 36 can be made from a less expensive steel, wherein the inner ring 31 made from rolling bearing steel is set on the pin 36. Here, the outer shape of the pin 36 is adapted in the area of the inner ring seat to the inner ring 31 and has a positioning effect in the axial direction. This pin inner ring arrangement can replace the one-piece pin 6 of the embodiment of FIG. 1 in an economical way.

(25) In the assembled state, the rows of rolling bodies have different radial clearance values. This means that the rolling bodies are loaded non-uniformly in a low load state between the rings without bending. This is not problematic, however, because both the edge wear in the support bearing and also the non-uniform loading of the rows of rolling bodies have little influence with respect to the service life.

(26) FIG. 8 shows another embodiment in longitudinal section along the rotational axis RA. The shown support bearing is based on needles as rolling bodies 42 that roll on the profiled, stationary shaft 40 that contains lubricating oil supply 46 in its interior. The rolling bodies 42 are held axially by the holding rings 48 that are provided for holding a lip seal 45 and are also sealed toward the outer ring 41 with an O-ring 48. In addition, the holding rings 48 have a radially placed groove 44.

(27) The entire arrangement is secured with the snap-on rings 47 attached on both sides and compensates the bending of the pin by means of a profiling on the pin 40. Optionally, profiling could still be provided on the inner raceways of the outer ring 41.

(28) FIG. 9 shows a schematic illustration of a pin outer surface, as could be provided in the embodiment of FIGS. 6 and 7.

(29) The shown pin outer surface is provided with three outer raceways 30a, b, c, namely two outer raceways 30a, c and one middle raceway 30b. The outer raceways 30a, c are arranged in the profiled area of the pin, wherein the profiling is shown schematically for better illustration (with an exaggerated small profiling radius R.sub.K2). The middle raceway 30b runs on a middle, cylindrical section of the pin. All of the raceways are formed integrally with the profiling in the circumferential direction (flattened section) 50. This means that the axial profiling in the load area transition at least partially into the profiling in the circumferential direction 50, in particular, this is not formed over the entire circumference but instead only in the load area.

(30) All radii of curvature must be designed sufficiently large enough that the transitions between the flattened section 50 and the pure profiled area do not cause damage during the rolling operation.

(31) In addition, it is to be stated generally for all embodiments that both the inner ring and also the outer ring have a ring shape with respect to the respectively formed raceway. The inner ring must be radially on the inside but does not necessarily have to have a ring shape. Instead it could be solid or have any other conceivable shape or could be partially or completely integrated into a different component, wherein the component itself does not have to have a ring shape. A corresponding situation exists for the shape of the outer ring in the radial direction outward away from its inner raceway.

LIST OF REFERENCE SYMBOLS

(32) B Reference point E Eccentricity F Maximum material removal F.sub.B For generating the bending moment L Load zone R Raceway radius RA Rotational axis R.sub.H Main direction of support force R.sub.K1 First radius of curvature in the circumferential direction (flattened section) R.sub.K2 Second radius of curvature of the profiling in the axial direction 1 Rolling body 2 Outer ring 3 Rolling bearing cage 4 Right base ring 5 Left base ring 6 Pin 7 Profiled pin section 8 Axial hole for lubricant line 9 Radial hole for lubricant line 10 Support force 11 Boundary 12 Holding point 13 Axial position x 14 Force direction 15 Bending line 16 Bending line 17 Radial correction function w(x) 18 Material removal 19 Raceway area with reduced curvature 20a Outer ring segment 20b Middle ring segment 20c Outer ring segment 21 Lubricant opening 22 Individual profiling 23 Inner ring 24 Outer ring 25 Axial width of conical area 26 Conical area 27 End groove 30a Outer raceway on outer surface 30b Middle raceway on outer surface 30c Outer raceway on outer surface 31 Inner ring 33 Lubricant opening 34 Opening 35a Profiled inner raceway 35b Profiled inner raceway 35c Profiled inner raceway 40 Pin 41 Outer ring 42 Needle 43 O-ring 44 Inner groove 45 Lip seal 46 Lubricating oil supply 47 Snap-on ring 48 Retaining ring 50 Flattened section