Design method, calculation method and bearing of double-row spherical roller bearing without partial load

Abstract

The present invention discloses a design method, a calculation method and a bearing for a double-row spherical roller bearing without eccentric load based on a skew angle. The skew angle can be obtained through basic design information of the eccentric load. The design of the skew angle can effectively avoid the dilemma that conventional empirical settings cannot obtain the optimal solution, unify its design standards, avoid the dilemma that the empirical value setting cannot reach the optimal solution, effectively solve the problem of eccentric load caused by the bearing being subjected to a large combined load, resulting in premature failure of one row of rollers due to excessive load, and improve the fatigue life of the bearing.

Description

Technical Field

[0001] The present invention belongs to the technical field of mechanical equipment, and in particular relates to a design method, a use method and a bearing of a double-row spherical roller bearing with no eccentric load based on a skew angle. Background Art

[0002] Double-row spherical roller bearings are usually used in low-speed and heavy-load machinery and equipment. The contact angles of the two rows of spherical roller bearings in conventional designs are designed to be symmetrical. When subjected to combined axial and radial loads, they are prone to uneven loading, that is, uneven force on the two rows of raceways. If the bearing is in an unevenly loaded state for a long time, the raceway with the heaviest load will suffer fatigue failure prematurely, reducing the fatigue life of the bearing. This requires that the contact angles of heavy-load double-row spherical roller bearings be designed to be asymmetrical.

[0003] Chinese patent CN106438683A discloses a spherical roller bearing comprising an outer ring, an inner ring, a cage disposed between the outer and inner rings and having two rows of pockets, and spherical rollers disposed in the cage pockets. An asymmetric spherical raceway is provided on the inner side of the outer ring. The asymmetric raceway is an arc-shaped sphere whose center does not coincide with the center of the bearing. The inner ring and cage are both configured to have an asymmetric structure corresponding to the asymmetric spherical raceway of the outer ring. Specifically, taking an existing spherical roller bearing with an original contact angle of 11.17° as an example, by rotating the original symmetrical spherical raceway 2° clockwise according to the above method, the contact angle on one side of the bearing is changed to 9.17° and the contact angle on the other side is changed to 13.17° through structural adjustment of the inner and outer rings of the bearing. When the spherical roller bearing is subjected only to radial loads and no axial loads, the radial force on the side with the contact angle of 9.17° is approximately 38% higher than that on the side with the contact angle of 13.17°.

[0004] However, in terms of how to design the contact angle, this kind of asymmetric contact angle design method has not yet been seen. Most designs are based on experience and cannot guarantee the maximum bearing life. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a design method, a calculation method and a bearing for a double-row spherical roller bearing without eccentric load based on a skew angle.

[0006] The present invention is achieved through the following technical solutions:

[0007] In the above technical solution,

[0008] A design method for double-row spherical roller bearings without eccentric load based on the deflection angle. The contact angle of the bearing raceway is ; The contact angle of the lightly loaded raceway is ,angle It is called the deflection angle;

[0009] ;

[0010] and is the axial and radial displacement of the bearing after being loaded;

[0011] ;

[0012] is the equivalent axial force, Fr is the equivalent radial force, To improve the initial contact angle, is the azimuth, is the calculation formula for the raceway-rolling element contact load, where subscripts 1 and 2 represent the left and right columns, respectively.

[0013] A method for calculating the contact angle of the raceway of a double-row spherical roller bearing without eccentric load, including:

[0014] 1) Obtain equivalent axial force , equivalent radial force , initial contact angle , azimuth ,

[0015] 2) Calculate the axial and radial displacement of the bearing after it is loaded and ,

[0016] 3) Calculated as the deflection angle , then the bearing raceway contact angle is ; The contact angle of the lightly loaded raceway is .

[0017] The calculation formula in step 2) is:

[0018] ;

[0019] is the equivalent axial force, is the equivalent radial force, To improve the initial contact angle, is the azimuth, is the calculation formula for the raceway-rolling element contact load, where subscripts 1 and 2 represent the left and right columns, respectively.

[0020] The calculation formula in step 3) is:

[0021] ;

[0022] A bearing obtained by the method.

[0023] The advantages and beneficial effects of the present invention are:

[0024] The present invention can directly calculate the effective deflection angle through a formula based on the design parameters of the bearing, unify its design standards, avoid the dilemma of not being able to achieve the optimal value due to empirical value settings, effectively solve the problem of overloading the bearing due to a large combined load, which causes a row of rollers to be overloaded and fail prematurely, and improve the fatigue life of the bearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the double-row spherical roller bearing structure;

[0026] Figure 2 This is the force analysis diagram of double row spherical roller bearing;

[0027] Figure 3 This is the force analysis diagram of double row spherical roller bearing;

[0028] Figure 4 Azimuth angle of double row spherical roller bearing Schematic diagram of the change of the center of curvature of the inner and outer raceways at ;

[0029] Figure 5 Improved front raceway-roller contact load for the first embodiment;

[0030] Figure 6 The contact load distribution of the two rows of raceways and rollers after the improvement of the first embodiment

[0031] Figure 7 Improved left raceway-roller contact stress distribution diagram for the second embodiment;

[0032] Figure 8 The right raceway-roller contact stress distribution diagram before the improvement of the second embodiment;

[0033] Figure 9 This is the left raceway-roller contact stress distribution diagram after improvement of the second embodiment;

[0034] Figure 10 This is the improved right raceway-roller contact stress distribution diagram of the second embodiment;

[0035] For ordinary technicians in this field, other relevant drawings can be obtained based on the above drawings without any creative work. DETAILED DESCRIPTION

[0036] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention are further described below with reference to specific embodiments.

[0037] Double row spherical roller bearings such as Figure 1 and 2 As shown, before the improvement, the roller-raceway contact angles of the left and right rows are Under the premise of ensuring that the outer dimensions of the bearing remain unchanged, the contact angle of the bearing raceway is appropriately increased. The adjustment angle on the right is ; The contact angle of the lightly loaded raceway is appropriately reduced. The adjustment angle on the left is ,angle It is called the deflection angle, and its value can be obtained by making the radial load maximum (position angle = 0) and the elastic deformation of the roller-raceway contact of the left and right rows is equal to eliminate the unbalanced load phenomenon of the two rows of raceways, and we can get ,in and The axial and radial displacements of the bearing after being loaded. After the bearing structure is optimized, the raceway center will shift. The optimized spherical roller bearing can effectively solve the problem of eccentric load caused by combined load and extend the service life of the bearing.

[0038] Skew angle The specific solution method is as follows:

[0039] Double row spherical roller bearings can generally withstand axial and radial forces, such as Figure 3 shown.

[0040] Assume that the curvature radius of the inner and outer raceways of the bearing is and , the rolling element diameter is , the radial clearance of the bearing is The center distance of curvature of the inner and outer raceways of the left and right rows at any angular position before loading Equal, the calculation formula is:

[0041] (1)

[0042] Before the bearing is loaded, when the clearance between the rolling element and the raceway is 0, the distance between the centers of curvature of the inner and outer rings of the contact pair of any rolling element position is:

[0043] (2)

[0044] According to the geometric relationship in the figure, the azimuth angle after loading =0, the distance between the inner and outer ring curvature centers becomes 、 (Subscripts 1 and 2 represent the left and right columns), the calculation formula is

[0045] (3)

[0046] (4)

[0047] in, and They are the axial and radial displacements of the bearing inner ring under external load, respectively.

[0048] The contact elastic deformation of the left and right rows of rolling elements and the inner and outer rings is:

[0049] (5)

[0050] make , then we can get

[0051] (6)

[0052] According to Hertz point contact theory, the relationship between contact load and elastic deformation is:

[0053] , is the contact deformation coefficient (7)

[0054] Since the contact deformation of the two rows of rollers and raceways is the same, the contact forces of the two rows of rollers and raceways are equal.

[0055] From this we can get the azimuth The contact load calculation formula for the left and right raceway-rolling elements is:

[0056] (8)

[0057] The overall balance equation of the bearing inner ring is:

[0058] (9)

[0059] Given bearing geometry and external load Fa and Fr. Under these conditions, solving equations (9) yields and Value. and Substituting the value into formula (6) can obtain the angle The value of .

[0060] The present invention can directly calculate the effective deflection angle through a formula based on the design parameters of the bearing, unify its design standards, avoid the dilemma of not being able to achieve the optimal value due to empirical value settings, effectively solve the problem of overloading the bearing due to a large combined load, which causes a row of rollers to be overloaded and fail prematurely, and improve the fatigue life of the bearing.

[0061] Example 1

[0062] Take a double row spherical roller bearing, the equivalent axial force it receives is =150kN, equivalent radial force =938kN, initial contact angle before improvement =10°, inner groove curvature radius =450mm, outer ring groove curvature radius =640mm, roller diameter D=92mm, radial clearance =0.5mm, number of rollers Z=64.

[0063] After calculation, the contact load between the two rows of rollers and raceways of the improved bearing is as follows: Figure 5 As shown in the figure, it can be seen that the load on the second row of rollers is much greater than the contact load on the rollers and raceways of the first row. As a result, the second row of raceways is prone to fatigue failure first, reducing the life of the bearing.

[0064] Substituting the above loads and geometric parameters into equation group (9), we can obtain the numerical solution by computer. =122.39 μm, =8.58μm, then according to formula (6) The deflection angle can be obtained =4°

[0065] After the calculation is improved, the contact load between the two rows of rollers and the raceway of the bearing is as follows: Figure 6 As shown in the figure, the contact force of the rollers on both sides after the improvement is less than that of the roller on the right side before the improvement, eliminating the unbalanced load phenomenon, increasing the bearing life and avoiding early bearing failure.

[0066] Example 2

[0067] Take a double row spherical roller bearing, the axial force it receives =250kN, radial force =800kN, initial contact angle before improvement =10°, inner groove curvature radius =450mm, outer ring groove curvature radius =640mm, roller diameter D=95mm, radial clearance =0.5mm, number of rollers Z=64.

[0068] The improved forward angle calculated by software is: =0 o The contact stress distribution of the left and right roller-raceways is shown in Figure 7 and 8 , the contact forces are 50KN and 151KN respectively.

[0069] Substituting the above loads and geometric parameters into equation group (9), we can obtain the numerical solution by computer. =54.9μm, =799μm, then according to formula (6 ), the azimuth angle can be obtained =0 o When the deflection angle =3.93°

[0070] After the software calculation, the improved azimuth angle is =0 o The contact stress distribution of the left and right roller-raceways is shown in Figure 9 and 10 , the contact forces of the two are 101KN and 103KN.

[0071] Before the improvement, the right roller was subjected to greater force, prone to early failure and a shorter lifespan. After the improvement, the contact force between the rollers on both sides is less than that of the right roller before the improvement, eliminating the unbalanced load phenomenon, extending the bearing lifespan and avoiding early failure of the bearing.

[0072] Example 3

[0073] A method for calculating the contact angle of the raceway of a double-row spherical roller bearing without eccentric load, including:

[0074] 1) Obtain equivalent axial force , equivalent radial force , initial contact angle , azimuth ,

[0075] 2) Calculate the axial and radial displacement of the bearing after it is loaded and ,

[0076] 3) Calculated as the deflection angle , the bearing raceway contact angle is ; The contact angle of the lightly loaded raceway is ;

[0077] Wherein, the calculation formula in step 2) is: ;

[0078] The calculation formula in step 3) is: ;

[0079] The above calculation method is used to obtain the deflection angle. The deflection angle can be obtained through the basic design information of the eccentric load. The design of the deflection angle can effectively avoid the dilemma that conventional experience settings cannot obtain the optimal solution. The effective deflection angle can be quickly obtained for different working conditions.

[0080] Example 4

[0081] A bearing obtained by the method described above is a main shaft bearing of a wind turbine. The bearing obtained by the method has an optimal deflection angle, can effectively achieve force balance between two rows of rollers, and effectively extend its service life and running stability.

[0082] The above is an exemplary description of the present invention. It should be noted that, without departing from the core of the present invention, any simple deformation, modification or other equivalent replacement that can be made by other skilled in the art without expending creative labor falls within the scope of protection of the present invention.

Claims

1. A design method for a double-row spherical roller bearing with no eccentric load based on the skew angle, characterized by: Assume that the curvature radius of the inner and outer raceways of the bearing is and , the rolling element diameter is , the radial clearance of the bearing is , the center distance of curvature of the inner and outer raceways of the left and right rows at any angular position before loading Equal, the calculation formula is, （1）， Before the bearing is loaded, when the clearance between the rolling element and the raceway is 0, the distance between the centers of curvature of the inner and outer rings of the contact pair of any rolling element position is, （2）， Azimuth after loading =0, the distance between the inner and outer ring curvature centers becomes , where subscripts 1 and 2 represent the left and right columns, and the calculation formula is, （3）， （4）， in, and are the axial and radial displacements of the bearing inner ring under external load, The contact elastic deformation of the left and right rows of rolling elements and the inner and outer rings is: （5）， make , then we can get, （6）， According to Hertz point contact theory, the relationship between contact load and elastic deformation is: , is the contact deformation coefficient (7), Since the contact deformation of the two rows of rollers and raceways is the same, the contact forces of the two rows of rollers and raceways are equal. From this we can get the azimuth The contact load calculation formula for the left and right raceway-rolling elements is: （8）， The overall balance equation of the bearing inner ring is: (9) ， Fa is the equivalent axial force, Fr is the equivalent radial force, To improve the initial contact angle, is the azimuth, The calculation formula for the contact load between the raceway and the rolling element is: and Value, put and Substituting the value into formula (6) can obtain the angle The value of the bearing weight, the raceway contact angle is , the contact angle of the lightly loaded raceway is ,angle is called the skew angle, 。 2. The design method of a double-row spherical roller bearing with no eccentric load based on the skew angle according to claim 1, characterized in that: The double-row spherical roller bearing is subjected to an equivalent axial force Fa = 150kN, an equivalent radial force Fr = 938kN, and an initial contact angle before improvement. =10°, inner groove curvature radius =450mm, outer ring groove curvature radius =640mm, roller diameter D=92mm, radial clearance =0.5mm, number of rollers Z=64, deflection angle =4°.

3. The design method of a double-row spherical roller bearing with no eccentric load based on the skew angle according to claim 1, characterized in that: The double row spherical roller bearing is subjected to an axial force Fa = 250kN, a radial force Fr = 800kN, and an initial contact angle before improvement. =10°, inner groove curvature radius =450mm, outer ring groove curvature radius =640mm, roller diameter D=95mm, radial clearance =0.5mm, number of rollers Z=64, deflection angle =3.93°.

4. A method for calculating the contact angle of the raceway of a double-row spherical roller bearing without eccentric load, characterized in that: include, 1) Obtain the equivalent axial force Fa, equivalent radial force Fr, and initial contact angle , azimuth , 2) Calculate the axial and radial displacement of the bearing after it is loaded and , 3) Calculated as the deflection angle , then the bearing raceway contact angle is ; The contact angle of the lightly loaded raceway is , the calculation formula in step 2) is: Fa is the equivalent axial force, Fr is the equivalent radial force, To improve the initial contact angle, is the azimuth, is the calculation formula for the raceway-rolling element contact load, where subscripts 1 and 2 represent the left and right columns, respectively. The calculation formula in step 3) is: 。 5. A bearing obtained by the method according to claim 1 or 4.

6. The bearing according to claim 5, wherein: The bearing is a main shaft bearing of a wind turbine generator.

Images