Spherical roller bearing
By setting inclined grooves on the raceway of the inner bearing ring, the contact angle between the roller and the raceway is changed, which solves the problem of sliding speed in the roller contact area of the self-aligning roller bearing, reduces friction loss and material stress, and improves the operating stability of the bearing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SCHAEFFLER TECHNOLOGIES AG & CO KG
- Filing Date
- 2021-07-16
- Publication Date
- 2026-04-21
AI Technical Summary
In existing self-aligning roller bearings, pressure ellipses are easily formed in the contact area between the rollers and the raceways of the bearing rings, causing the highest sliding speed to occur at the edge of the rolling contact, resulting in friction loss and high material stress.
By setting inclined grooves on the raceway of the inner bearing ring, the contact point between the roller and the raceway is deviated from the pressure line, changing the contact angle of the roller in the bearing and reducing or avoiding roller setting during operation.
This reduces the sliding speed between the rollers and raceways, decreases friction loss and material stress, and improves the operating stability and efficiency of the bearing.
Smart Images
Figure CN116615612B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to self-aligning roller bearings, and more particularly to the rolling behavior of rollers on the raceway of such self-aligning roller bearings. Background Technology
[0002] Self-aligning roller bearings typically have an inner bearing ring, an outer bearing ring arranged coaxially with the inner bearing ring, and rollers arranged in at least one roller bank, wherein the rollers in the at least one roller bank have curved lateral surfaces extending along the rotation axis of these rollers with a radius of R1, wherein the rollers in the at least one roller bank roll on curved raceways provided by different bearing rings, wherein each of these raceways is assigned a groove point P1; P2, the curved raceway of the associated bearing ring extending about the groove point along the rotation axis DA2 of the bearing at a radial distance R2; R3, wherein the pressure line DL intersects the rotation axis DA1 of the rollers in the at least one roller bank at a right angle at the point where these rollers have their maximum roller diameter, and wherein R1 is smaller than both radii R2 and R3.
[0003] This type of self-aligning roller bearing is known from DE 10 2008 037 990 A1.
[0004] When such a self-aligning roller bearing is put into operation, the rollers self-align between the raceways of the bearing rings so that the contact area between the rollers and the raceways lies within the region of the maximum roller diameter, i.e., forming a so-called pressure ellipse in this region. Since the shape of the outer ring raceway along the bearing's axis of rotation—geometrically speaking—describes a portion of a hollow sphere on which one or more rollers can freely adjust, the contact with the inner ring determines how the rollers self-align within the bearing, where the resulting contact angle between the inner ring and the rollers structurally corresponds to the bearing's pressure angle.
[0005] Generally speaking, on the inner ring of a self-aligning roller bearing, the highest sliding speeds tend to occur in the edge regions of the rolling contact. Depending on the pressure angle and / or the difference between the raceway radii of the inner and outer bearing rings, these higher sliding speeds may occur in the axial inner or outer edge regions of the rolling contact, resulting in frictional losses in these regions, which implies higher roller settling and / or consequently higher material stress.
[0006] To address this problem, DE 2 334 394A1 proposes raceways with inner and / or outer bearing rings having non-constant radii. Besides the fact that running profiles with small, constant radii can only be manufactured with considerable effort, the raceway profiles provided by the applicant impair the axial positioning of the rollers in the load zone of the bearing and lead to undesirable lateral slippage of the rollers.
[0007] Therefore, the present invention is based on the objective of specifying a self-aligning roller bearing in which the contact area where the highest sliding speed otherwise occurs is released in a simple manner. Summary of the Invention
[0008] If the raceway for the rollers in at least one roller bank in one of the bearing rings has a groove point P1 on the pressure line DL with an associated groove point P2 giving a raceway radius R2, and the raceway for the rollers in at least one roller bank in the other bearing ring has a groove point P2 on the line L with an associated groove point P3, and if the pressure lines DL and L have a common intersection point SP1, the radial distance A1 from the common intersection point to the groove point P2 is less than the radial distance A2 from the groove point P1, the raceways on the two bearing rings are arranged at an angle relative to each other around the intersection point SP1.
[0009] The bearing ring whose raceway is inclined relative to the raceway of the other bearing ring should preferably be the inner bearing ring, because this does not change the manufacturing workload of the outer bearing ring, and whether the raceway on the inner bearing ring is formed on the groove point P2 located on the printing line DL or on another groove point P2 located around the line L is irrelevant to production.
[0010] If we disregard the manufacturing advantages of the outer bearing ring, which arise from the uniform inner contour between the ends of the bearing ring having only one radius, the inner contour of the outer bearing ring can also have two segments, each describing one radius, which merge together in the middle of the outer bearing ring. Attached Figure Description
[0011] Figure 1 An arrangement based on the prior art is shown;
[0012] Figure 2 An arrangement according to the invention is shown, and
[0013] Figure 3 Another arrangement according to the invention is shown. Detailed Implementation
[0014] exist Figure 1 The image shows a roller bearing in the form of a double-row self-aligning roller bearing 1. This self-aligning roller bearing 1 is basically formed by an inner bearing ring 2, an outer bearing ring 3, and rollers 4.
[0015] Each roller 4 has two end surfaces 5, which are maintained at a distance from each other along the axis of rotation DA1 of the roller 4, corresponding to the width B of the roller. The lateral surfaces 6 of the roller 4 are curved, wherein the curvature of each lateral surface 6 of each roller 4 describes the radius R1.
[0016] According to Figure 1 As shown in the diagram, the roller 4 used belongs to either the first roller bank 7.1 or the second roller bank 7.2. The two roller banks 7.1 and 7.2 maintain a distance from each other along the bearing's axis of rotation DA2.
[0017] Each of the two bearing rings 2 and 3 is provided with at least one raceway 8.n. In the context of this application, raceway 8.n is understood to refer to an annular surface located on the radial outer contours 9.1 and 9.2 in the case of the inner bearing ring 2 and on its radial inner contours 9.1 and 9.2 in the case of the outer bearing ring 3, the annular surface having an extension along the direction of the bearing's rotation axis DA2 in each case, and on which the roller 4 disposed between the two bearing rings 2 and 3 rolls when the bearing is installed.
[0018] because Figure 1 The bearing shown is a double-row self-aligning roller bearing 1. Rollers 4 are assembled on this double-row self-aligning roller bearing to form a first roller row 7.1 and a second roller row 7.2. Each of the two bearing rings 2 and 3 also has two raceways 8.1, 8.2; 8.3, 8.4. This becomes particularly clear for the inner bearing ring 2, which has a protrusion 10 on its outer contour 9.1 that separates the two raceways 8.1, 8.2 and extends in the direction of the outer bearing ring 3. In order to enable the installation of the double-row self-aligning roller bearing and ensure that the axis of rotation D2 of the bearing or the shaft 11 connected to the inner bearing ring 2 can be tilted relative to the outer bearing ring 3, the two raceways 8.3, 8.4 form a common raceway occupying the entire inner contour 9.2 of the outer bearing ring 3.
[0019] Just like the curved lateral surface 6 of the roller 4 arranged between the two bearing rings 2 and 3, each raceway in the raceways 8.n is also curved. The common raceways 8.3 and 8.4, extending completely along the inner contour 9.2 of the outer bearing ring 3 between the axial ends 12 of the outer bearing ring, have a uniform curvature with a radius R2, which is slightly larger than the radius R1 of the corresponding lateral surface 6 of the roller 4. Therefore, the common raceways 8.3 and 8.4 are provided with cavities relative to the longitudinal extension of the roller 4. The inner bearing ring 2 is similar. However, due to the X arrangement of the roller 4 between the bearing rings 2 and 3, there are two raceways 8.1 and 8.2, which are axially separated from each other by a protrusion 10, wherein each of these raceways 8.1 and 8.2 has a uniform curvature with a radius R3, which is also slightly larger than the radius R1 of the corresponding lateral surface 6 of the roller 4. Therefore, each of the two separate raceways 8.1 and 8.2 on the inner bearing ring 2 is also provided with a cavity relative to the longitudinal extension of the roller 4. Even according to Figure 1The radii R2 and R3 shown in the diagram have the same dimensions. These radii R2 and R3 can also have different dimensions so that the roller 4 is guided, for example, by a smaller degree of contact between the roller 4 and the corresponding raceways 8.1, 8.2 on the inner bearing ring than the greater degree of contact on the outer bearing ring 3. Here, the quotient between the corresponding running radii R2 and R3 and the radius I of the lateral surface of the roller 4, multiplied by 100%, is considered as the degree of contact, such that when comparing a large degree of contact with a small degree of contact, the quotient is only slightly higher than 100% in the case of a small degree of contact and in the case of a large degree of contact, and the quotient is larger when the percentage is further greater than 100%.
[0020] When a double-row self-aligning roller bearing 1 is installed, the lateral surface 6 of the roller 4 and the corresponding raceway 8.n form a contact point 13.n. Figure 1 In the case of the conventionally designed self-aligning roller bearing 1 shown, the expected connecting line extending from the inner bearing ring 2 and the outer bearing ring 3 through the corresponding contact points 13.1, 13.2 between the lateral surfaces 6 of the respective rollers 4 and the corresponding raceways 8.n intersects the rotation axis DA1 of the rollers 4 at a right angle, which is identified as the angle γ relevant to this application. Simultaneously, the connecting line forming the so-called pressure line DL extends at the so-called pressure angle α, which is related to the perpendicular line S intersecting the rotation axis DA2 of the bearing at a right angle. Generally, as... Figure 1 As shown, in the case of the double-row self-aligning roller bearing 1, the contact angles α of the two roller rows 7.1 and 7.2 are the same.
[0021] In connection with this application, a self-aligning roller bearing 1 in which the contact angle α is the same for both roller rows 7.1, 7.2 is generally referred to as a symmetrical self-aligning roller bearing 1. However, double-row self-aligning roller bearings are also known to be used to improve the distribution of axial loads, wherein the contact angle α of the two roller rows 7.1, 7.2 has different dimensions. Such bearings are called asymmetrical self-aligning roller bearings.
[0022] Structurally, this means at least in Figure 1 In the case of a symmetrical self-aligning roller bearing 1 of the type shown, the radii R2 and R3 of the raceways 8.n have their corresponding recessed points P1 and P2 on the pressure line DL. This means that in the case of an installed self-aligning roller bearing 1, where the rollers 4 are arranged between two bearing rings 2 and 3, if – conventionally – the imaginary recessed point P3 of radius R1 on the lateral surface 6 is also located on the pressure line DL, then the lateral surface 6 of the two bearing rings, described by the curvature of radius R1, only has contact points 13.1 and 13.2 with the corresponding raceways 8.1, 8.3; 8.2, 8.4.
[0023] However, if the symmetrical self-aligning roller bearing 1 is formed as follows Figure 1As shown, it cannot be ruled out that roller 4 will be set during the operation of this bearing, as described at the beginning.
[0024] In order to reduce or completely eliminate the setting of roller 4 during operation, based on the arrangement corresponding to the prior art, only the structural conditions of one of the two bearing rings 2 and 3 are changed. Figure 2 This embodiment described in the present invention is illustrated in the figure.
[0025] Here, as explained in the previous paragraph, the outer bearing ring 3 forms a constant bearing ring because the groove point P1 corresponding to the radius R2 of the common raceways 8.3 and 8.4 is also located on the pressure line DL, specifically at the position where the common raceway intersects with the bearing's axis of rotation DA2. Therefore, the contact point 13.1 between the rollers 4 of the two roller rows 7.1 and 7.2 and the common raceways 8.3 and 8.4 is also located where the roller 4 has its maximum roller diameter D1.
[0026] In contrast, the groove point P2 of the radius R3 of the raceways 8.1 and 8.2 of the inner bearing ring 2 on the following line L: this line includes an angle β relative to the vertical line S in each case, and this line intersects the pressure line DL at point SP.
[0027] The angle β is a function of the pressure angle α of the raceway involved (8.1, 8.2, or 8.2, 8.4) and the corresponding radii R2 and R3. Because in Figure 2 In the embodiment shown, the radius R2 of the common raceways 8.3 and 8.4 of the outer bearing ring 3 is smaller than the radius R3 of the raceways 8.1 and 8.2 of the inner bearing ring 2. Therefore, according to the following relationship...
[0028] ,
[0029] It can be deduced that angle β is less than pressure angle α.
[0030] Due to the difference between the two angles α and β and the fact that the groove point P2 of the raceways 8.1 and 8.2 on the inner bearing ring 2 maintains a larger radial distance from the groove point P3 of the common raceways 8.3 and 8.4 on the outer bearing ring 3 relative to the rotation axis DA2 of the bearing, the radial distance A1 of the intersection point SP from the corresponding groove point P2 is less than the radial distance A2 of the intersection point SP from the groove point P1.
[0031] The angular offset between the groove points P2 and P3 of the corresponding raceways 8.n does not cause the contact point 13.2 between the roller 4 and the corresponding raceways 8.1 and 8.2 to change, i.e., to shift along the raceways 8.1 and 8.2. Instead, although the groove point P2 of the raceways 8.1 and 8.2 is located on the line L extending at angle β, the contact point 13.2 between the roller 4 and the raceways 8.1 and 8.2 of the inner bearing ring 2 is essentially the location where the roller 4 has its maximum diameter D1. However, because the raceways 8.1 and 8.2 of the inner bearing ring 2 are tilted due to their groove points P2 on line L, the contact conditions between the roller 4 and the corresponding raceways 8.1 and 8.2 change, resulting in a slight axial outward expansion of the pressure ellipse that normally changes under load to form the corresponding contact point 13.2. This axial extension is indicated by reference numeral 14 for the roller bank 7.1. This inclination of raceways 8.1 and 8.2 has another result: relative to the corresponding contact point 13.2, the raceways 8.1 and 8.2 are... Figure 2 The section with the central axis inwardly adjacent to the contact point and the corresponding curvature Figure 1 Compared to the previous implementation, it has a flatter protrusion. Due to the smaller circumference of the raceways 8.1 and 8.2, the flatter protrusion in the corresponding curvature of the raceways 8.1 and 8.2 of the inner bearing ring 2 then reduces the higher sliding speed between the corresponding raceways 8.1 and 8.2 and the roller 4.
[0032] Figure 3 Another embodiment according to the invention is shown, which is different from the embodiment according to... Figure 2 The difference in the implementation is that the radius R2 of the common raceways 8.3 and 8.4 on the outer bearing ring 3 is larger than the radius R3 of the corresponding raceways 8.1 and 8.2 on the inner bearing ring 2, and therefore, according to the following relationship
[0033] ,
[0034] The angle β of the straight line L extending below it is greater than the pressure angle α. Because angle β is greater than the pressure angle α, when the bearing is loaded, the resulting pressure ellipse expands axially inward from the contact point 13.2. This axially inward turning region... Figure 3 The middle part is indicated by reference numeral 14 in relation to the left roller bank 7.1. The change in contact conditions in this manner then leads to... Figure 2 The condition is reversed, that is, the curved areas of raceways 8.1 and 8.2 adjacent to contact point 13.2 are relative to the condition according to... Figure 1 The raceways 8.1 and 8.2 are increased more axially inward, while the adjacent area axially outward is increased less. This design is advantageous under strong axial loads on the bearing.
[0035] According to Figure 2Exemplary implementations and according to Figure 3 In both exemplary embodiments, the surface roughnesses a1 and b1 of the various raceways 8.n can be different from each other. For example, after correspondingly finer machining of the raceways 8.1 and 8.2 of the inner bearing ring 2, the surface roughness a1 of the raceways can be lower than the surface roughness b1 of the common raceways 8.3 and 8.4 of the outer bearing ring 3. In addition to the pure surface roughness of the respective raceways 8n given only by machining and / or coating, there is also a so-called operational roughness a.2 on the raceways 8.2 and 8.3 of the outer bearing ring 3, or an operational roughness b.2 on the raceways 8.1 and 8.2 of the inner bearing ring 2, which also affects the rolling behavior of the roller 4 between the raceways 8.n. Within the meaning of this application, the so-called operational roughnesses a.2 and b.2 are understood to refer to variables that only become apparent during the operation of the bearing, and sometimes may also interact with the corresponding surface roughnesses a.1 and b.1. Only the bearing speed and the viscosity of the lubricant used are examples of operational roughness. Since the operating roughnesses a2, b2 appearing on raceways 8.1 and 8.2 of the inner bearing ring 2 during bearing operation may differ in size from the operating roughnesses a2, b2 of raceways 8.3 and 8.4 of the outer bearing ring 3, it is advantageous to consider the corresponding roughnesses a1, b2 or a1, b2 of different raceways 8.n when designing the bearing or angle β. This is successful if so-called roughness coefficients f1, f2 are assigned to each of the raceways involved in 8.1, 8.2 or 8.3, 8.4 based on roughnesses a.1 and / or a2 or b1 and / or b2.
[0036] When designing the angle β, the formulas for the roughness coefficients f1 and f2 of different raceways 8.1, 8.2, 8.3, and 8.4 can be obtained from the following relationships:
[0037] ,
[0038] Here, R2 is also the radius of the common raceways 8.3 and 8.4 in the outer bearing ring 3, R3 is the radius of the common raceways 8.1 and 8.2 in the inner bearing ring 2, f1 is the roughness coefficient on the common raceways 8.3 and 8.4 of the outer bearing ring 3, and f.2 is the roughness coefficient on the raceways 8.1 and 8.2 of the inner bearing ring 2.
[0039] List of reference numerals
[0040] 1 Self-aligning roller bearings
[0041] 2 Inner bearing ring
[0042] 3. Outer bearing ring
[0043] 4 rollers
[0044] 5. End surface
[0045] 6 Lateral surfaces
[0046] 7.1, 7.2 First roller bank or second roller bank
[0047] 8.n Roller track
[0048] 9.1, 9.2 Inner or outer contour
[0049] 10. Protrusions
[0050] 11-axis
[0051] 12 ends
[0052] 13.n Contact Point
[0053] 14 Extension
Claims
1. A self-aligning roller bearing, It has an inner bearing ring (2). It has an outer bearing ring (3), which is coaxially arranged relative to the inner bearing ring (2), and It has rollers (4), said rollers being arranged in at least one roller row (7.1, 7.2), wherein, The roller (4) in the at least one roller row (7.1, 7.2) has a curved lateral surface (6) extending along the direction of the rotation axis DA1 of the roller (4) and having a radius of R1, wherein the roller (4) in the at least one roller row (7.1, 7.2) rolls on curved raceways (8.n) provided by different bearing rings (2, 3), wherein each raceway (8.n) is assigned a groove point P1; P2, the curved raceway (8.n) of the bearing ring (2; 3) extending around the groove point P1; P2 at a radial distance R2; R3 along the rotation axis DA2 of the bearing, wherein the pressure line DL intersects the rotation axis DA1 of the roller (4) in the at least one roller row (7.1; 7.2) at an angle α of 90° at the point P where the roller (4) has the maximum roller diameter D1 of the roller, and wherein R1 is less than two radii R2, R3, characterized in that The raceway (8.3, 8.4; 8.1, 8.2) used by the roller (4) in at least one roller row (7.1; 7.2) at one of the bearing rings (2, 3) has a groove point P1 on the pressure line DL that is associated with the raceway and gives a raceway radius R2. The raceway (8.1, 8.2; 8.3, 8.4) used by the roller (4) in the at least one roller row (7.1, 7.2) on another bearing ring has a groove point P2 on line L that is associated with the raceway and gives a raceway radius R3. Furthermore, the pressure line DL and the line L share a common intersection point SP, and the radial distance A1 from the intersection point to the groove point P2 is less than the radial distance A2 from the groove point P1. The intersection SP simultaneously forms the center point of the radius R1 of the curved lateral surface (6) of the roller (4) in the at least one roller row (7.1, 7.2).
2. The self-aligning roller bearing according to claim 1, characterized in that... The raceways (8.3, 8.4) with the groove point P1 located on the pressure line DL are the raceways (8.3, 8.4) of the outer bearing ring (3), and The groove point P2 of the raceway (8.1, 8.2) is located on the line L.
3. The self-aligning roller bearing according to any one of claims 1 or 2, characterized in that... The raceway radius R2 is different from the raceway radius R3.
4. The self-aligning roller bearing according to any one of claims 1 or 2, characterized in that... The pressure line DL and the line L are angularly related as follows: β= arcsin (R2 / R3 * sin (α)), Wherein, relative to the perpendicular line S extending through the groove point P1 and perpendicular to the axis of rotation DA2 of the bearing, angle α represents the pressure angle of the pressure line DL, and angle β represents the angle of the line L, and wherein R2 is the radius of the raceway (8.3, 8.4) on the outer bearing ring (3), and R3 is the radius of the raceway (8.1, 8.2) on the inner bearing ring (2).
5. The self-aligning roller bearing according to any one of claims 1 or 2, characterized in that... The surface roughness a1 and / or operational roughness a2 of one raceway (8.1, 8.2) is different from the surface roughness b1 and / or operational roughness b2 of the other raceway (8.3, 8.4).
6. The self-aligning roller bearing according to any one of claims 1 or 2, characterized in that... The self-aligning roller bearing is a double-row self-aligning roller bearing, and has a first roller row (7.1) and a second roller row (7.2).
7. The self-aligning roller bearing according to claim 6, characterized in that... The first roller row (7.1) and the second roller row (7.2), together with the rollers (4) in the first roller row and the second roller row, are mirror-symmetrical with respect to the center line M perpendicular to the axis of rotation DL2 of the bearing, with respect to the raceways (8.n) of the first roller row and the second roller row in the inner bearing ring (2) and the outer bearing ring (3).
8. The self-aligning roller bearing according to claim 6, characterized in that... The pressure angles DW of the two roller rows (7.1, 7.2) have different magnitudes.
Citation Information
Patent Citations
Sealed bearing
DE102008037990A1
Self-aligning roller bearing
US4828404A