KR100734133B1 - Optimal Design Method Improved Rolling Contact Surface of Spherical Roller Bearings - Google Patents

Abstract

An optimal design method improving a rolling contact surface of a spherical roller is provided to smooth a movement by reducing a friction due to loads of a radial weight and a trust weight. An optimal design method improving a rolling contact surface of a spherical roller include a standard spherical roller bearing. A curve surface(CV) forms an out race at inner surface of an outer wheel(100). The curve surface is formed with a center(H0) of a horizontal shaft direction and a radius(R) restrained within a width(B) of the outer wheel. Curve surfaces(CV1,CV2) forms an inner race at inner surface of an inner wheel(200). The curve surfaces are formed with a contacting angle of 10~15degrees between a line connecting a contacting point of the roller and a shaft cross section of the bearing, a center of a crossing point(P) facing to the center of the horizontal shaft direction, and radiuses(R1,R2) formed at outer surface of the inner wheel.

Description

Optimal Design Method Improved Rolling Contact Surface of Spherical Roller Bearings {.}

1 is a cross-sectional view showing an example in which a spherical roller bearing to which the present invention is applied.

Figure 2 is a perspective view of a portion of the conventional spherical roller bearing cut away

Figure 3 is a cross-sectional view illustrating the design conditions of a conventional standard spherical roller bearing

Figure 4 is a cross-sectional view showing the relationship of the load acting in the conventional standard spherical roller bearing

5 is a cross-sectional view of the first embodiment of the present invention.

Fig. 6 is a sectional view of a bearing illustrating the design conditions of the first embodiment of the present invention.

7 is a view showing the relationship of the load acting in the first embodiment of the present invention

8 illustrates the design conditions of the roller in the first embodiment of the present invention.

9 is a cross-sectional view illustrating design conditions of the outer ring in the first embodiment of the present invention.

10 is a cross-sectional view illustrating the design conditions of the inner ring in the first embodiment of the present invention.

11 is a cross-sectional view of a second embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings

100 · 100a: outer ring
200 · 200a: inner ring

300 · 300a: Roller
E1: Extension wire for axial load
E2: extension lines from both sides
E3: extension line extending from the horizontal axial center
F1: axial load
F2: radial load
F3: Composite Load
CV: Surface to form outrace
CV1 ・ CV2: curved surface to form inner race
S1 · S2: Space where maximum diameter of roller is accommodated

The present invention maximizes the contact area of the ball bearing (Ball Bearing), using the rolling shape of the cylindrical roller bearing (Cylindrical Roller Bearing), and self-aligning type according to the principle of mixing used to displace the contact angle The present invention relates to a spherical roller bearing designed to have a heart-shaped function. More specifically, the spherical roller bearing is designed to have a high load (high load) by applying various displacements to the contact angle by improving the contact area between the outer ring and the inner ring. The present invention relates to an optimal design method that improves the rolling contact surface of spherical roller bearings in order to maximize the contact surface to withstand iii) and improve the dynamic characteristics in the direction of the load acting on the bearing.

The self-aligning roller bearing is a double-row type with spherical orbits on the outer ring. The self-aligning roller bearing can compensate for misalignment, deflection of the shaft, deformation of the housing, etc. The distortion of the roller is automatically adjusted, and it is divided into a cylindrical roller bearing in which the outer circumferential surface of the roller has a uniform cylindrical diameter, and a spherical roller bearing in the shape of a barrel in which both ends of the outer circumferential surface of the roller are narrowed.

Insulated roller bearings with spherical raceway surfaces were first in German Patent 135220 in 1902, double row in British Patent 1617 in 1911, and the current structure is in accordance with German Patents 331454 and 331651 in 1920. Known.

1 is a cross-sectional view showing an example in which a conventional spherical bearing is applied.

As is well known, the spherical roller bearing having the self-aligning function has a roller-shaped roller (30, 30a) having a rolling surface between the outer ring 10 having a spherical track and the inner ring 20 having a two-row track. ) And the cage, barrel-shaped rollers (30, 30a) symmetrical in two rows are centered freely on the raceway surface of the outer ring 10 of the spherical surface so that the center of curvature of the raceway surface of the outer ring (20) As it coincides, it is automatically adjusted when there is a deflection of the shaft or housing or when the shaft center does not coincide, so that no excessive force is applied.

Such spherical roller bearings can be subjected to radial and axial loads at the same time, and are particularly used for applications in which heavy loads or impact loads are applied due to their large radial load capacity.

The function required of the bearings is to maintain a constant period of time with large load capacity and stiffness, low friction loss and quiet rotation.

The load applied when the bearing is selected and the load capacity of the bearing have a significant influence on the life of the bearing.Therefore, there should be no plastic deformation or fatigue at the inner ring, outer ring, or roller of the bearing, and allowable plastic deformation between the inner and outer rings of the bearing and the roller. In the range of 0.01% of the maximum diameter of the roller, quiet operation and fatigue life of the bearing are not shortened.

Therefore, the allowable plastic strain due to the contact pressure between the inner and outer rings of the spherical bearing and the roller is directly related to the noise and the service life. When the allowable plastic strain is within 1 / 10,000 of the maximum roller diameter, quiet operation is It is possible and does not shorten the fatigue life of the bearing.

In general, the static load rating Co of the radial roller bearing is obtained by the following equation (1).

Where I: quantity of roller rows in the bearing

       z: Quantity of rollers in one column

       dw: maximum diameter of the roller

l _eff: Effective contact length of roller

α _0: Angle formed between the line connecting the contact point of the roller and the shaft end surface of the bearing (contact angle)

       T: Pitch circle diameter formed by rollers

As can be seen from the above equation, the maximum diameter of the roller is one of the important parameters for determining the static load factor. Therefore, it can be seen that the static load coefficient increases as the maximum diameter of the roller increases, and the maximum diameter of the roller is given when the inner diameter (d) of the inner ring, the outer diameter (D) of the outer ring, and the width (B) in the axial direction are the same. It becomes clear that the larger the maximum diameter of the conventional roller, the greater the static load coefficient, so that the allowable plastic strain does not exceed 0.01% of the maximum diameter of the roller, resulting in quiet operation and shortened fatigue life of the bearing.

2 shows a general structure of a spherical roller bearing.

Spherical roller bearings having the structure as shown are manufactured by a standard design method according to DIN616 (ISO15), which is defined in terms of the outer dimensions of the bearings.

The geometric correlation of the basic dimensions in this standard design is shown in FIG. 3.

The design method of the standard spherical roller bearing includes the inner diameter (d) of the inner ring (20), the outer diameter (D) of the outer ring (10), the width in the axial direction (B), and the contact point at which the roller 30 contacts the roller 30. The maximum thickness of the outer ring 10: the maximum diameter of the roller 30: the maximum thickness of the inner ring 20 is 1: 2: To satisfy.

Referring to FIG. 3, the ratio of the inner diameter d of the inner ring, the outer diameter D of the outer ring, and the width B in the axial direction is calculated by Equation 2 below, and each condition is expressed by Equation 3 below. Calculated by

Where d is the inner diameter of the inner ring, D is the outer diameter of the outer ring, and B is the width in the axial direction.

Figure 4 shows the relationship of the load acting in the conventional standard spherical roller bearing.

3 and 4, in the standard spherical roller bearing designed based on the above equation, the curved surface CV forming the outer race inside the outer ring 10 may have the outer ring 10 from the horizontal axial center H0. The curved surface CV1 and CV2 which are formed by the radius R defined in the width | variety B of which the width | variety B is formed, and which form inner race in the outer side of the inner ring | wheel 20 form the width | variety B of a bearing. Formed by radii R1 and R2 formed on the outer surface of the inner ring 20 about the intersection P of the extension line E2 from both sides and the extension line E3 extending from the horizontal axis center H0. The space where the extension line E3 is formed between the curved surface CV forming the outer race and the curved surfaces CV1 and CV2 forming the inner race forms a space S1 and S2 in which the maximum diameter of the roller is accommodated. do.

That is, the maximum diameter (C1) of the roller is taken into consideration of the combined load (F3) of the load (F1) acting in the axial direction and the load (F2) acting in the radial direction of the roller at the position where the combined load (F3) acts. Since the maximum diameter is placed, it is possible to cope with axial and radial loads with the self-aligning function.

When the bearing system is at rest or in motion and is subjected to excessive loads or large impact loads, local permanent deformation is inevitably generated between the rolling surface and the rolling element, and when the permanent deformation exceeds a certain limit, the bearing is smooth. It has a dynamic characteristic that makes it difficult to exercise.

In order to reduce the friction and load acting on the rollers in order to reduce the friction and load applied to the rollers in order to extend the smooth operation and life of the rollers in the spherical roller bearings, the maximum diameter of the rollers must be variably designed. A curved surface CV forming an out race is formed by a radius R defined within a range in which the width B of the outer ring 10 is formed from the center H0, and an extension line E2 from both sides of the bearing is formed. Curved surface CV1 that forms an inner race by radii R1 and R2 formed on the outer surface of the inner ring 20 about the intersection P of the extension line E3 extending from the center H0 in the horizontal axis direction. Under the condition that CV2) is formed, each of the radiuses R and the dimensions of R1 and R2 are made larger or smaller to design the maximum diameter of the roller.

However, the above design conditions cannot be coped with multi-functional composite loads because the direction under which the combined load F3 acts by the axial load F1 and the radial load F2 is a given condition. The constraint is that the width B should be designed larger or smaller.

Such conventional standard spherical roller bearings can exhibit optimized dynamic characteristics with respect to the direction of load when the ratio of the inner diameter (d) of the inner ring, the outer diameter (D) of the outer ring, and the width (B) in the axial direction is constant. There is no design limitation.

Even after the bearing is used under normal conditions for a certain period of time, scalp damage, ie play, may be caused by repeated stresses on the sound, vibration, deterioration of wear, deterioration of grease, raceways or rolling elements. King occurs and is no longer available. The rolling fatigue life of the bearings in relation to the total number of revolutions and the period until the bearings become unavailable has a large spread even when a group of identical bearings are operated under the same conditions. This is because the fatigue of the material itself is not constant. Therefore, taking life as an average is meaningless, so use the rated life as a statistic.

Basic nominal life is the total number of revolutions or total rotation time when a group of identical bearings are rotated under identical conditions, of which 90% of the bearings can rotate without causing flaking due to rolling fatigue.

The basic dynamic load rating, which represents the dynamic load capacity of a bearing, refers to a load in which the rated fatigue life can be 1 million revolutions in a condition that the outer ring is fixed and the inner ring rotates. Load, and the thrust bearing takes a pure axial load.

 The equivalent dynamic load rating and equivalent load rating and basic life rating in accordance with ISO 281 / I and KS B 2019 are as shown in Equation 1 below, and when the basic rating life is expressed as rotation time, There is a similar relationship.

Where L: bearing life with unit million revolutions

       C: Dynamic load factor of the bearing (basic dynamic load rating) [N], {kgf}

       P: Constant load on the bearing (equivalent load) [N], {kgf}

       C / P: Dynamic Load Safety

Where L _h is the bearing life in hours (hr)

       n: revolutions per minute (rpm)

Assuming that the life of the bearing is damaged by the fatigue of the material, it is affected by the shape of the material and the contact area, the amount of pressure exerted on the roller, the load variation per unit time and the number of cycles of the change cycle. In particular, the life of a spherical roller bearing is a variable in which the shape and position of the roller corresponding to the load in the rolling contact surface formed by the inner and outer rings with the roller are important in the direction of the radial load, the axial load, and the combined load. Will act as. Therefore, even if the ratio of the inner diameter (d) of the inner ring, the outer diameter (D) of the outer ring, and the width (B) in the axial direction is constant, it is more useful for the system to be designed so that it can flexibly respond to the direction in which the load is applied. Can be applied.

The present invention utilizes a rolling shape of a cylindrical roller bearing even if the ratio of the inner diameter d of the inner ring, the outer diameter D of the outer ring D, and the width B in the axial direction is constant. Maximizes the contact area, and unlike general spherical roller bearings, it is designed to be mixed to be applied arbitrarily according to the axial load ratio to radial load by shifting the contact angle by asymmetrical rollers. It is a special purpose bearing that can withstand high loads with self-aligning function, and to provide spherical roller bearings capable of receiving both radial and axial loads and combined loads simultaneously.

The present invention for achieving the above object in the design of the spherical roller bearing by the contact angle according to the axial load and the radial load,

In the standard spherical roller bearing, the curved surface CV forming the outer race inside the outer ring 100 has a radius R defined within a range in which the width B of the outer ring 10 is formed from the horizontal axial center H0. Formed by;

Curved surfaces CV1 and CV2 forming an inner race inside the inner ring 200 have a contact angle formed with a line connecting the contact points of the rollers and an axial end surface of the bearing, that is, an extension line E1 which becomes an axial load F1 and a bearing The angle at which the extension line E3 constituting the combined load F3 forms the vertical axis V0 with the vertical axis E by an extension line E2 which becomes a radial load F2 from the outside of both sides forming the width B. α ₀ ) becomes 10 to 15 °, toward the center of the horizontal axis in the horizontal axis direction H0 with respect to the intersection point P, and a radius formed on the outer surface of the inner ring 20 about the intersection point P It is formed by R1, R2).

Another feature of the present invention is to design a spherical roller bearing by the contact angle according to the axial load and the radial load,

In the standard spherical roller bearing, the curved surface CV forming the outer race inside the outer ring 100a is defined by a radius R defined within a range in which the width B of the outer ring 100a is formed from the horizontal axial center H0. Formed by;

Extension line forming the combined load F3 by the extension line E1 serving as the axial load F1 and the extension line E2 serving as the radial load F2 from the inside of both sides forming the width B of the bearing. The angle α ₀ , which E3 forms with the center V0 in the vertical axis direction becomes 5 to 10 °, toward the center H0 in the horizontal axis direction with respect to the intersection P, and the center of the intersection P in the center. It is characterized in that formed by the radius (R1, R2) formed on the outer surface of the inner ring (200a).

According to the present invention, in the special case in which the contact angle is given according to the axial load and radial load in the space according to DIN616 (ISO15), which defines the outer dimensions of the bearing, the inner dimensions of the outer ring, the inner ring, and the roller can be set. The design time can be dramatically reduced by optimizing the curvature ratio of the and the raceway surface to have the uniform stress distribution and the large load capacity.The design time can be drastically reduced, and the radial load, the axial load, and the combined load The friction torque is small even under load, so it can be used for applications requiring high speed rotation, low noise and low vibration.

Therefore, according to the present invention, a specific type of design method that satisfies a given contact angle according to the axial load and radial load in the design of a spherical roller bearing improves the static load coefficient to within 0.01% of the maximum diameter. A spherical roller bearing can be provided which allows for quieter operation and can extend the fatigue life of the bearing.

In addition, the present invention is a special-purpose bearing manufactured according to the hybrid design principle that can be applied arbitrarily according to the axial load ratio to the radial load by shifting the contact angle, unlike the general spherical roller bearing It has the advantage of providing a spherical roller bearing that can withstand high loads and can simultaneously receive various acting radial and axial loads and combined loads.

Features and advantages of the present invention will be more clearly described by the embodiments described by the accompanying drawings.

An embodiment of the present invention will be described in detail with reference to the accompanying drawings.

6 is a cross-sectional view illustrating design conditions associated with the first embodiment of the present invention, and FIG. 7 is a cross-sectional view illustrating load conditions.

The roller diameter ratio may be arbitrarily given as a variable in the geometrical relationship of the standard spherical roller bearing described above. In most cases, the diameter ratio is 0.45 to 0.55, and the default value is 0.5.

In the context of the present invention, the correlation of the basic dimensions will be explained for the case where the contact angle Sα is additionally given considering the ratio of the axial load and the radial load. . This case corresponds to the case where the axial load needs to be considered a special design depending on the boundary conditions.

Therefore, the relation is a case where the following equation (6) is established.

The ratio of the inner diameter d of the inner ring, the outer diameter D of the outer ring, and the width B in the axial direction is calculated by Equation 7 below, and the respective conditions are calculated by Equation 8.

8 is a diagram illustrating a design condition of a roller in the first embodiment of the present invention.

9 is a view illustrating a design condition of the outer ring in the first embodiment of the present invention, the relationship is expressed by the following equation (10).

10 is a diagram illustrating a design condition of the inner ring in the first embodiment of the present invention.

The spherical roller bearing designed according to the first embodiment has a radial load formed outside the extension line E1 of the axial load and the width B of the bearing on the basis of the curved surface CV forming the outlace. Radius (R1, R2) formed on the outer surface of the inner ring 20 with respect to the extension line (E3) in the direction of the combined load extending from the intersection point (P) of the extension line (E2) to the horizontal axis direction center (H0) Between the curved surfaces CV1 and CV2 forming the inner race, the spaces S1 and S2 in which the asymmetrical rollers are located are formed, and the maximum diameter of the asymmetrical rollers is accommodated in the space in which the extension line E3 is formed. It is loaded with the frictional force of.

That is, the maximum diameter (C1) of the roller is the position at which the combined load is applied in the standard spherical roller bearing in consideration of the combined load (F3) of the load (F1) acting in the axial direction and the load (F2) acting in the radial direction. Since the composite load (F3) acts on the outer side, the maximum diameter of the roller is placed, so that it can cope with axial and radial loads within a wider range with the self-aligning function.

Fig. 11 shows a sectional view of a bearing illustrating the design conditions of the second embodiment of the present invention.

Referring to this figure, the intersection point P of the extension line E1 of the axial load and the extension line E2 of the radial load formed inside the width B of the bearing with respect to the curved surface CV forming the outlace. Curved surfaces CV1 and CV2 that form inner races by radii R1 and R2 formed on the outer surface of the inner ring 200a with respect to the extension line E3 which becomes the direction of the combined load extending from the horizontal axis center H0 to Asymmetrical rollers 300 and 300a are positioned between each other, and the maximum diameter of the asymmetrical rollers 300 and 300a is accommodated in the space where the extension line E3 is formed and is loaded with a minimum frictional force.

That is, the maximum diameter (C1) of the roller 300 is the combined load in the standard spherical roller bearing in consideration of the combined load (F3) of the load (F1) acting in the axial direction and the load (F2) acting in the radial direction Since the combined load (F3) acts inward from the position to act, the maximum diameter of the roller is placed so that it can cope with the axial and radial loads within a narrow range with the self-aligning function.

As described above, the present invention can be manufactured by knowing the size of the inner space, even if it is not an ISO standard, and the design conditions and dimensions of the outer diameter are determined, so that the compatibility of the roller roller can be satisfied even if it is applied to any application. By improving the contact area, the curvature ratio of the raceway wheel is optimized to have equal stress distribution and large load capacity in the direction of radial load, axial load, and composite load. By reducing the friction against the load of the overload and the thrust load, the movement is smooth and the proper cooling functions.

Therefore, by the optimal design method that improved the rolling contact surface of the spherical roller bearing of the present invention, the bearing life is extended to enable high speed rotation of the shaft, and high speed rotation, low noise and low vibration are required by maintaining the rigidity and damping of the oil film. Spherical roller bearings suitable for the application are provided.

Claims (4)

In designing spherical roller bearings by contact angles in accordance with axial and radial loads, In the standard spherical roller bearing, the curved surface CV forming the outer race inside the outer ring 100 has a radius R defined within a range in which the width B of the outer ring 10 is formed from the horizontal axial center H0. Formed by; The curved surfaces CV1 and CV2 forming the inner race on the outside of the inner ring 200 have the intersection point of the radial load F2 from the outside of both sides forming the axial load F1 and the width B of the bearing ( The synthetic load F3 formed from P) is directed toward the center H0 in the horizontal axis direction, and is formed by radii R1 and R2 formed on the outer surface of the inner ring 20 about the intersection point P. Optimal design method with improved rolling contact surface of spherical roller bearings. In designing spherical roller bearings by contact angles in accordance with axial and radial loads, In the standard spherical roller bearing, the curved surface CV forming the outer race inside the outer ring 100a is defined by a radius R defined within a range in which the width B of the outer ring 100a is formed from the horizontal axial center H0. Formed by; The curved surfaces CV1 and CV2 forming the inner race on the outside of the inner ring 200 have the intersection of the radial load F2 from the inside of both sides forming the axial load F1 and the width B of the bearing ( The combined load F3 formed from P is directed toward the center H0 in the horizontal axis direction about the intersection P, and the radius R1, which is formed on the outer surface of the inner ring 200a about the intersection P, is formed. Optimal design method with improved rolling contact surface of spherical roller bearing, characterized in that formed by R2). The optimal design method according to claim 1, wherein the angle α ₀ between the vertical axis center V0 and the horizontal axis center H0 is 10 to 15 °. The optimal design method according to claim 2, wherein the angle α ₀ between the vertical center V0 and the horizontal center H0 is 5 to 10 degrees.

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