Method for calculating bearing assembly preload

Abstract

The application provides a bearing assembly pre-tightening amount calculation method, which is suitable for a gearbox cone bearing system. The method comprises the following steps: obtaining the interference parameters of the gearbox cone bearing system, and calculating the first elongation of the first bearing and the second elongation of the second bearing according to the interference parameters; obtaining the axial parameters of the gearbox cone bearing system, and calculating the gap value between the shell assembly and the bearing assembly according to the axial parameters; obtaining the first pre-tightening parameters of the first bearing and the second pre-tightening parameters of the second bearing, and determining the pre-tightening amount between the bearing assembly and the shell assembly according to the first pre-tightening parameters, the first elongation, the second pre-tightening parameters, the second elongation and the gap value. The pre-tightening amount required by the bearing assembly can be calculated more accurately according to the scheme. The appropriate gasket can be selected according to the pre-tightening amount, so that the bearing assembly can work under the optimal pre-tightening force, and the full working potential of the bearing assembly can be tapped. The service life of the cone bearing and the gearbox is prolonged.

Description

Technical Field

[0001] This invention relates to the field of tapered bearing selection technology, and in particular to a method for calculating bearing assembly preload. Background Technology

[0002] The output shaft of a gearbox is typically supported by two paired tapered bearings. Tapered bearings can withstand large axial and radial forces and have superior performance. However, during gearbox operation, the temperature rises significantly. The gearbox housing and the tapered bearing shaft system expand and deform due to this temperature increase, creating a gap between the tapered bearing and the housing. To compensate for this gap, shims are installed to provide a certain preload to the tapered bearing. Appropriate preload allows for axial interference fit in the tapered bearing, improving its lifespan and precision, and consequently, the gearbox's lifespan. The choice of shims has a significant impact on the preload.

[0003] When selecting gaskets for existing tapered bearings, the axial and radial thermal deformation relationship between the tapered bearing and the housing, as well as the axial deformation characteristics of the tapered bearing and the housing under gasket preload, are considered. The specific calculation method for the preload can be found in the following formula:

[0004]

[0005] Where S represents the preload, and S0 represents the theoretical clearance between the housing depth and the two outer rings of the tapered bearing, i.e., the difference between the sum of the two housing depths and the distance between the large end faces of the two tapered bearing outer rings. A S represents the theoretical preload of a tapered bearing. T1 S represents the elongation of the axial clearance between the tapered bearing and the housing due to the difference in their coefficients of thermal expansion. T2 S represents the elongation caused by the radial deformation of the housing and shaft system due to their different coefficients of thermal expansion, which ultimately translates into the axial clearance between the tapered bearing and the housing. K This indicates the axial deformation of the housing and shaft system under the theoretical preload.

[0006] However, experiments show that a larger preload determined by the above method also means a larger shim thickness. Tapered cone bearings are prone to failure and reduced bearing life when operating under excessive preload conditions. Summary of the Invention

[0007] The purpose of this invention is to solve the problem in the prior art that excessive preload makes tapered bearings prone to failure, thereby reducing the service life of bearings and gearboxes.

[0008] To address the aforementioned problems, embodiments of the present invention disclose a method for calculating bearing assembly preload, applicable to gearbox tapered bearing systems. The gearbox tapered bearing system includes: a housing assembly comprising a first housing and a second housing, the first and second housings being spaced apart in the axial direction of the housing assembly; and a bearing assembly comprising a first bearing, a second bearing, and a shaft, the first and second bearings being respectively disposed at both ends of the shaft, the bearing assembly being disposed between the first and second housings, and the axial direction of the bearing assembly coinciding with the axial direction of the housing assembly. Furthermore, the method for calculating bearing assembly preload includes the following steps:

[0009] S1: Obtain the interference parameters of the gearbox tapered bearing system, and calculate the first elongation of the first bearing and the second elongation of the second bearing based on the interference parameters.

[0010] S2: Obtain the axial parameters of the gearbox tapered bearing system, and calculate the clearance value between the housing assembly and the bearing assembly based on the axial parameters;

[0011] S3: Obtain the first preload parameter of the first bearing and the second preload parameter of the second bearing, and determine the preload amount between the bearing assembly and the housing assembly based on the first preload parameter, the first elongation, the second preload parameter, the second elongation, and the clearance value.

[0012] By adopting the above scheme, the axial elongation of the bearing assembly caused by the interference fit of the shaft hole between the bearing assembly and the housing assembly, namely the first elongation and the second elongation, can be calculated more accurately. As a result, the preload required for bearing assembly can be calculated more accurately. Therefore, a suitable shim can be selected according to the appropriate preload, so that the bearing assembly and housing assembly can work under the best preload force, the bearing assembly is not prone to failure, and the service life of the bearing and the gearbox is extended.

[0013] According to another specific embodiment of the present invention, the bearing assembly preload calculation method disclosed in this embodiment includes, in step S1, the interference parameters including the outer diameter of the outer ring of the first bearing, the outer diameter of the outer ring of the second bearing, the diameter of the mounting hole of the first housing for mounting the first bearing, and the diameter of the mounting hole of the second housing for mounting the second bearing; and step S1 includes:

[0014] Obtain the first calculation parameters of the first bearing, and calculate the first elongation based on the outer diameter of the outer ring of the first bearing, the bore diameter of the first housing, and the first calculation parameters;

[0015] Obtain the second calculation parameters of the second bearing, and calculate the second elongation based on the outer diameter of the outer ring of the second bearing, the bore diameter of the second housing, and the second calculation parameters.

[0016] According to another specific embodiment of the present invention, the method for calculating bearing assembly preload disclosed in this embodiment includes a first calculation parameter comprising a first bearing coefficient and a first bearing constant; a second calculation parameter comprising a second bearing coefficient and a second bearing constant; and a first elongation calculated according to the following formula:

[0017] S 11 =C1*(D b1 -D c1 )+b1

[0018] Among them, S 11 C1 is the first elongation, and D is the first bearing coefficient. b1 D is the outer diameter of the outer ring of the first bearing. c1 Let b be the diameter of the first housing, and b1 be the first bearing constant; and calculate the second elongation according to the following formula:

[0019] S 12 =C2*(D b2 -D c2 )+b2

[0020] Among them, S 12 C2 is the second elongation, and D is the second bearing coefficient. b2 D is the outer diameter of the outer ring of the second bearing. c2 b1 is the aperture of the second housing, and b2 is the constant of the second bearing.

[0021] Using the above scheme, the first elongation and the second elongation can be calculated based only on the bearing coefficient, bearing constant, outer diameter of the bearing outer ring, and bore diameter of the housing. There is no need to calculate the axial and radial deformation of the housing assembly and bearing assembly under different interference fits, which can reduce the amount of calculation and improve the calculation efficiency.

[0022] According to another specific embodiment of the present invention, the method for calculating the bearing assembly preload disclosed in this embodiment of the present invention includes obtaining the first calculation parameters of the first bearing as follows:

[0023] Obtain the first radial deformation of the first bearing, the first axial deformation of the first bearing, and the half-cone angle of the inner raceway of the first outer ring of the first bearing;

[0024] The formula for calculating the elongation of the first bearing is determined based on the first radial deformation, the first axial deformation, and the half-cone angle of the inner raceway of the first outer ring.

[0025] Based on the elongation calculation formula for the first bearing, and using linear regression and computer-aided engineering to determine the first calculation parameters; furthermore, the second calculation parameters for the second bearing are obtained, including:

[0026] Obtain the second radial deformation of the second bearing, the second axial deformation of the second bearing, and the half-cone angle of the inner raceway of the second outer ring of the second bearing;

[0027] The formula for calculating the elongation of the second bearing is determined based on the second radial deformation, the second axial deformation, and the half-cone angle of the inner raceway of the second outer ring.

[0028] The second calculation parameter is determined based on the elongation calculation formula of the second bearing and using linear regression and computer-aided engineering.

[0029] By adopting the above scheme, the calculation formulas for the elongation of the first bearing and the second bearing are simplified using linear regression and computer-aided engineering, thereby improving the accuracy of the simplified formulas.

[0030] According to another specific embodiment of the present invention, the method for calculating the bearing assembly preload disclosed in this embodiment of the present invention uses the following formula for calculating the elongation of the first bearing:

[0031] S 11’ =ΔR1*Cot(θ1)+ΔA1

[0032] Among them, S 11’ Let ΔR1 be the elongation of the first bearing, θ1 be the first radial deformation, θ1 be the semi-cone angle of the inner raceway of the first outer ring, and ΔA1 be the first axial deformation; and the formula for calculating the elongation of the second bearing is:

[0033] S 12’ =ΔR2*Cot(θ2)+ΔA2

[0034] Among them, S 12’ ΔR2 is the elongation of the second bearing, θ2 is the second radial deformation, θ2 is the semi-cone angle of the inner raceway of the second outer ring, and ΔA2 is the second axial deformation.

[0035] According to another specific embodiment of the present invention, the bearing assembly preload calculation method disclosed in this embodiment includes interference parameters such as the first radial deformation of the first bearing, the second radial deformation of the second bearing, the first axial deformation of the first bearing, the second axial deformation of the second bearing, the half-cone angle of the inner raceway of the first outer ring of the first bearing, and the half-cone angle of the inner raceway of the second outer ring of the second bearing; and step S1 includes:

[0036] The first elongation is calculated based on the first radial deformation, the first axial deformation, and the half-cone angle of the inner raceway of the first outer ring;

[0037] The second elongation is calculated based on the second radial deformation, the second axial deformation, and the half-cone angle of the inner raceway of the second outer ring.

[0038] By adopting the above scheme, the first elongation and the second elongation are directly calculated by utilizing the axial and radial deformations of the housing assembly and bearing assembly under different interference fits, resulting in more accurate calculation results.

[0039] According to another specific embodiment of the present invention, the method for calculating the bearing assembly preload disclosed in this embodiment calculates the first elongation according to the following formula:

[0040] S 11 =ΔR1*Cot(θ1)+ΔA1

[0041] Among them, S 11 ' is the first elongation, ΔR1 is the first radial deformation, θ1 is the half-cone angle of the inner raceway of the first outer ring, and ΔA1 is the first axial deformation; and the second elongation is calculated according to the following formula:

[0042] S 12 =ΔR2*Cot(θ2)+ΔA2

[0043] Among them, S 12 ' represents the second elongation, ΔR2 represents the second radial deformation, θ2 represents the half-cone angle of the inner raceway of the second outer ring, and ΔA2 represents the second axial deformation.

[0044] According to another specific embodiment of the present invention, in the method for calculating bearing assembly preload disclosed in this embodiment, step S2 involves calculating the clearance value between the housing assembly and the bearing assembly according to the following formula:

[0045] S0 = L c1 +L c2 -L s

[0046] Where S0 is the gap value, L c1 For the first depth, L c2 For the second depth, L s The length of the first and second bearings in the axial direction of the bearing assembly is given.

[0047] According to another specific embodiment of the present invention, in the bearing assembly preload calculation method disclosed in this embodiment, the first preload parameter in step S3 includes the theoretical preload of the first bearing, the axial clearance elongation between the first housing and the first bearing, the radial clearance elongation between the first housing and the first bearing, and the axial deformation of the first bearing under the theoretical preload of the first bearing.

[0048] The second preload parameters include the theoretical preload of the second bearing, the axial clearance elongation between the second housing and the second bearing, the radial clearance elongation between the second housing and the second bearing, and the axial deformation of the second bearing under the theoretical preload of the second bearing; and in step S3, the preload between the bearing assembly and the housing assembly is determined according to the following formula:

[0049] S = S0 - S 11 -S 12 +S A +S T1 +S T2 +S K

[0050] Alternatively, the preload between the bearing assembly and the housing assembly can be determined using the following formula:

[0051] S = S0 - S′ 11 -S′ 12 +S A +S T1 +S T2 +S K

[0052] Where S is the preload between the bearing assembly and the housing assembly, and S0 is the clearance between the housing assembly and the bearing assembly. 11 S′ 11 For the first elongation, S 12 S′ 12 This is the second elongation.

[0053] S A =S A1 +S A2 S A1 S is the theoretical preload of the first bearing. A2 This is the theoretical preload of the second bearing.

[0054] S T1 =S T11 +S T12 ,;S T11 S is the axial clearance elongation between the first housing and the first bearing. T12 , which is the axial clearance elongation between the second housing and the second bearing.

[0055] S T2 =S T21 +S T22 S T21 S is the radial clearance elongation between the first housing and the first bearing. T22 This refers to the radial clearance elongation between the second housing and the second bearing.

[0056] S K =SK1 +S K2 S K1 S represents the axial deformation of the first bearing under its theoretical preload; K2 This refers to the axial deformation of the second bearing under the theoretical preload of the second bearing.

[0057] By adopting the above scheme, the theoretical preload S required for the tapered bearing at its theoretical maximum life is comprehensively considered. A The relationship between the radial interference fit between the tapered bearing and the housing and the axial elongation of the tapered bearing; the axial deformation S of the tapered bearing and the housing at different temperatures. T1 And the radial deformation converted to the axial deformation S T2 and in the theoretical preload S A Axial elongation S of the lower tapered bearing and housing K It can accurately calculate the preload.

[0058] According to another specific embodiment of the present invention, the bearing assembly preload calculation method disclosed in this embodiment further includes, after step S3: determining the thickness of the shim between the first bearing and the first housing, and the thickness of the shim between the second bearing and the second housing, based on the preload between the bearing assembly and the housing assembly.

[0059] By adopting the above solution and selecting shims based on the calculated precise preload, the utilization potential of the tapered bearing can be maximized, thereby improving the service life of the gearbox.

[0060] The beneficial effects of this invention are:

[0061] This design considers the interference fit between the tapered bearing and the housing, thus subtracting the axial elongation of the tapered bearing when calculating the preload. It also considers the theoretical preload required for the tapered bearing's maximum theoretical lifespan, the axial and radial deformations of the tapered bearing and housing at different temperatures (converted to axial deformation), and the axial elongation of the tapered bearing and housing at the theoretical preload. Therefore, the calculated preload is more accurate, allowing for the selection of the optimal shim based on this precise preload. Consequently, the bearing operates under optimal preload, extending the service life of both the tapered bearing and the gearbox. Attached Figure Description

[0062] Figure 1 This is a schematic diagram of the structure of the gearbox cone bearing system provided in an embodiment of the present invention;

[0063] Figure 2 This is a flowchart illustrating the method for calculating bearing assembly preload provided in an embodiment of the present invention;

[0064] Figure 3This is a graph showing the relationship between the life of a tapered bearing and the preload of a tapered bearing, as provided in an embodiment of the present invention.

[0065] Explanation of reference numerals in the attached figures:

[0066] 1. Gearbox tapered bearing system; 11. Housing assembly; 111. First housing; 112. Second housing; 12. Bearing assembly; 121. First bearing; 122. Second bearing; 123. Shaft; L c1 The first depth of the first shell; L c2 The second depth of the second shell; L s The total length of the bearing assembly; D b1 The outer diameter of the outer ring of the first bearing; D c1 The aperture of the first shell; D b2 The outer diameter of the outer ring of the second bearing; D c2 The aperture of the second shell. Detailed Implementation

[0067] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention is presented in conjunction with preferred embodiments, this does not mean that the features of the invention are limited to these embodiments. On the contrary, the purpose of describing the invention in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of the present invention. To provide a deep understanding of the invention, many specific details will be included in the following description. The invention may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of the invention, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0068] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0069] In the description of this embodiment, it should be noted that the terms "upper", "lower", "inner", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the product of the invention is usually placed in during use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0070] The terms “first”, “second”, etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0071] In the description of this embodiment, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment based on the specific circumstances.

[0072] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0073] To address the problem in existing technologies where excessive preload can lead to tapered bearing failure and consequently reduce the service life of bearings and gearboxes, this invention provides a method for calculating bearing assembly preload, applicable to gearbox tapered bearing systems.

[0074] Specifically, refer to Figure 1 The gearbox tapered bearing system 1 includes a housing assembly 11 and a bearing assembly 12. The housing assembly 11 is the housing of the gearbox, and the bearing assembly 12 is the shaft system of the gearbox output shaft.

[0075] The housing assembly 11 includes a first housing 111 and a second housing 112, which are spaced apart in the axial direction of the housing assembly 11.

[0076] It should be noted that the axial direction of the housing assembly 11 is also... Figure 1 The horizontal direction in the middle.

[0077] The bearing assembly 12 includes a first bearing 121, a second bearing 122, and a shaft 123, with the first bearing 121 and the second bearing 122 respectively disposed at both ends of the shaft 123.

[0078] The bearing assembly 12 is disposed between the first housing 111 and the second housing 112. Furthermore, the axial direction of the bearing assembly 12 coincides with the axial direction of the housing assembly 11.

[0079] Both the first housing 111 and the second housing 112 have a certain depth so that the first bearing 121 and the second bearing 122 corresponding to them can be assembled into the housing.

[0080] The bearing assembly preload calculation method provided in this embodiment is applied to the aforementioned gearbox tapered bearing system 1. More specifically, refer to... Figure 2 The method for calculating bearing assembly preload provided in this embodiment includes the following steps:

[0081] S1: Obtain the interference parameters of the gearbox tapered bearing system, and calculate the first elongation of the first bearing and the second elongation of the second bearing based on the interference parameters.

[0082] S2: Obtain the axial parameters of the gearbox tapered bearing system, and calculate the clearance value between the housing assembly and the bearing assembly based on the axial parameters;

[0083] S3: Obtain the first preload parameter of the first bearing and the second preload parameter of the second bearing, and determine the preload amount between the bearing assembly and the housing assembly based on the first preload parameter, the first elongation, the second preload parameter, the second elongation, and the clearance value.

[0084] The above solution considers the interference fit between the tapered bearing and the housing, thus subtracting the axial elongation of the tapered bearing when calculating the preload. It also takes into account the theoretical preload required for the tapered bearing's maximum theoretical lifespan, the axial and radial deformations of the tapered bearing and housing at different temperatures (converting to axial deformation), and the axial elongation of the tapered bearing and housing at the theoretical preload. Therefore, the calculated preload is more accurate, allowing for the selection of the optimal shim based on this precise preload. This extends the service life of both the tapered bearing and the gearbox.

[0085] Next, refer to Figures 1-3 The method for calculating bearing assembly preload provided in the embodiments of the present invention will be described in detail.

[0086] First, execute step S1 to obtain the interference parameters of the gearbox tapered bearing system, and calculate the first elongation of the first bearing and the second elongation of the second bearing based on the interference parameters.

[0087] It should be noted that this embodiment provides two methods for calculating the first elongation and the second elongation, which will be described separately below.

[0088] First, a method for calculating the first elongation and the second elongation is described.

[0089] Specifically, in step S1, the interference parameters include the outer diameter of the outer ring of the first bearing 121, the outer diameter of the outer ring of the second bearing 122, the diameter of the mounting hole of the first housing 111 for mounting the first bearing 121, and the diameter of the mounting hole of the second housing 112 for mounting the second bearing 122.

[0090] In this bearing, the outer diameter of the outer ring of the first bearing 121 and the second bearing 122 is the outer diameter of the outermost ring of the first bearing 121 and the second bearing 122. The tapered bearing is not a regular cylindrical shape; its outermost ring diameter is the largest among all the outer diameters of the bearing. This can be measured using measuring tools such as a micrometer.

[0091] The diameter of the mounting hole for the first bearing 121 in the first housing 111 and the diameter of the mounting hole for the second bearing 122 in the second housing 112 can also be measured using measuring tools.

[0092] Furthermore, step S1 includes the following steps: First, obtain the first calculation parameters of the first bearing 121, and calculate the first elongation based on the outer diameter of the outer ring of the first bearing 121, the bore diameter of the first housing, and the first calculation parameters; Second, obtain the second calculation parameters of the second bearing 122, and calculate the second elongation based on the outer diameter of the outer ring of the second bearing 122, the bore diameter of the second housing, and the second calculation parameters.

[0093] The first calculation parameter includes the first bearing coefficient and the first bearing constant; the second calculation parameter includes the second bearing coefficient and the second bearing constant.

[0094] In this embodiment, the first elongation is calculated according to the following formula:

[0095] S 11 =C1*(D b1 -D c1 )+b1

[0096] Among them, S 11 C1 is the first elongation, and D is the first bearing coefficient. b1 D is the outer diameter of the outer ring of the first bearing. c1 b1 is the aperture of the first housing and b1 is the first bearing constant.

[0097] The second elongation is calculated using the following formula:

[0098] S 12 =C2*(D b2 -D c2 )+b2

[0099] Among them, S 12 C2 is the second elongation, and D is the second bearing coefficient. b2 D is the outer diameter of the outer ring of the second bearing. c2 b1 is the aperture of the second housing, and b2 is the constant of the second bearing.

[0100] It should be noted that, in this embodiment, the method for obtaining the first calculation parameters of the first bearing 121 is as follows: First, the first radial deformation, the first axial deformation, and the half-cone angle of the inner raceway of the first outer ring of the first bearing are obtained; then, the elongation calculation formula of the first bearing is determined based on the first radial deformation, the first axial deformation, and the half-cone angle of the inner raceway of the first outer ring; finally, the first calculation parameters are determined based on the elongation calculation formula of the first bearing and using linear regression and computer-aided engineering.

[0101] It should be explained that the first radial deformation refers to the radial deformation of the first bearing 121 under the interference fit of the mounting hole of the first bearing 121 and the first housing 111, which can be calculated by computer-aided engineering.

[0102] The first axial deformation refers to the axial deformation of the first bearing 121 under the interference fit of the mounting hole of the first bearing 121 and the first housing 111. It can also be obtained by computer-aided engineering calculation.

[0103] The half-cone angle of the inner raceway of the first outer ring is also the half-cone angle of the inner raceway of the outer ring of the first bearing 121. The specific calculation method can be found in existing technology, and will not be elaborated upon in this embodiment.

[0104] Similarly, the method for obtaining the second calculation parameters of the second bearing 122 is as follows: First, obtain the second radial deformation, the second axial deformation, and the half-cone angle of the inner raceway of the second outer ring of the second bearing; then, determine the elongation calculation formula of the second bearing based on the second radial deformation, the second axial deformation, and the half-cone angle of the inner raceway of the second outer ring; finally, determine the second calculation parameters based on the elongation calculation formula of the second bearing and using linear regression and computer-aided engineering.

[0105] It should be explained that the second radial deformation refers to the radial deformation of the second bearing 122 under the interference fit of the mounting hole of the second bearing 122 and the second housing 112, which can be calculated by computer-aided engineering.

[0106] The second axial deformation refers to the axial deformation of the second bearing 122 under the interference fit of the mounting hole of the second bearing 122 and the second housing 112. It can also be obtained by computer-aided engineering calculation.

[0107] The half-cone angle of the inner raceway of the second outer ring is also the half-cone angle of the inner raceway of the outer ring of the second bearing 122. The specific calculation method can be found in existing technology, and will not be elaborated upon in this embodiment.

[0108] It should be noted that the formula for calculating the elongation of the first bearing is:

[0109] S 11’ =ΔR1*Cot(θ1)+ΔA1

[0110] Among them, S 11’ ΔR1 is the elongation of the first bearing, θ1 is the first radial deformation, θ1 is the semi-cone angle of the inner raceway of the first outer ring, and ΔA1 is the first axial deformation.

[0111] The formula for calculating the elongation of the second bearing is:

[0112] S 12’ =ΔR2*Cot(θ2)+ΔA2

[0113] Among them, S 12’ ΔR2 is the elongation of the second bearing, θ2 is the second radial deformation, θ2 is the semi-cone angle of the inner raceway of the second outer ring, and ΔA2 is the second axial deformation.

[0114] The above describes the first method for calculating the first elongation and the second elongation provided in this embodiment. This method requires first processing and calculating the elongation calculation formulas for the first bearing and the second bearing to obtain the first bearing coefficient, the first bearing constant, the second bearing coefficient, and the second bearing constant. Then, based on the calculation results from computer-aided engineering, the elongation calculation formulas for the first bearing and the second bearing are simplified. The simplified formulas are then used to calculate the first elongation and the second elongation.

[0115] Since both the elongation calculation formulas for the first and second bearings involve the axial and radial deformations of the housing assembly 11 and bearing assembly 12 under different interference fits, simplifying the elongation calculation formulas for the first and second bearings avoids calculating the axial and radial deformations for each interference fit during the actual calculation of the preload. Therefore, it reduces the computational workload and improves computational efficiency.

[0116] This embodiment also provides a method for calculating the first elongation and the second elongation, that is, calculating the axial deformation and radial deformation of the housing assembly 11 and the bearing assembly 12 under different interference fits.

[0117] Specifically, the interference parameters include the first radial deformation of the first bearing, the second radial deformation of the second bearing, the first axial deformation of the first bearing, the second axial deformation of the second bearing, the half-cone angle of the inner raceway of the first outer ring of the first bearing, and the half-cone angle of the inner raceway of the second outer ring of the second bearing.

[0118] Furthermore, step S1 includes the following steps: First, calculate the first elongation based on the first radial deformation, the first axial deformation, and the half-cone angle of the inner raceway of the first outer ring; second, calculate the second elongation based on the second radial deformation, the second axial deformation, and the half-cone angle of the inner raceway of the second outer ring.

[0119] It should be noted that, in this embodiment, the first elongation is calculated according to the following formula:

[0120] S 11 =ΔR1*Cot(θ1)+ΔA1

[0121] Among them, S 11' represents the first elongation, ΔR1 represents the first radial deformation, θ1 represents the semi-cone angle of the inner raceway of the first outer ring, and ΔA1 represents the first axial deformation.

[0122] In this embodiment, the second elongation is calculated according to the following formula:

[0123] S 12 =ΔR2*Cot(θ2)+ΔA2

[0124] Among them, S 12 ' represents the second elongation, ΔR2 represents the second radial deformation, θ2 represents the half-cone angle of the inner raceway of the second outer ring, and ΔA2 represents the second axial deformation.

[0125] The above is the second method for calculating the first elongation and the second elongation provided in this embodiment. In this method, the first elongation and the second elongation are directly calculated by utilizing the axial deformation and radial deformation of the housing assembly 11 and the bearing assembly 12 under different interference fits.

[0126] In the actual calculation process, those skilled in the art can arbitrarily choose to calculate the first elongation and the second elongation according to the first method or the second method, and this embodiment does not impose any restrictions on this.

[0127] After completing step S1, proceed to step S2.

[0128] Step S2: Obtain the axial parameters of the gearbox tapered bearing system, and calculate the clearance value between the housing assembly and the bearing assembly based on the axial parameters.

[0129] Specifically, the axial parameters include the first depth of the first housing 111, the second depth of the second housing 112, and the total length of the first bearing 121 and the second bearing 122 in the axial direction of the bearing assembly.

[0130] The first depth, the second depth, and the total length of the first bearing 121 and the second bearing 122 in the axial direction of the bearing assembly can all be obtained by actual measurement using tools.

[0131] It should be noted that in step S2, the clearance value between the housing assembly and the bearing assembly is calculated according to the following formula:

[0132] S0 = L c1 +L c2 -L s

[0133] Where S0 is the gap value, L c1 For the first depth, L c2 For the second depth, L s The length of the first and second bearings in the axial direction of the bearing assembly is given.

[0134] Next, step S3 is executed to obtain the first preload parameter of the first bearing and the second preload parameter of the second bearing. Based on the first preload parameter, the first elongation, the second preload parameter, the second elongation, and the clearance value, the preload amount between the bearing assembly 12 and the housing assembly 11 is determined.

[0135] Specifically, in step S3, the first preload parameter includes the theoretical preload of the first bearing 121, the axial clearance elongation between the first housing 111 and the first bearing 121, the radial clearance elongation between the first housing 111 and the first bearing 121, and the axial deformation of the first bearing 121 under the theoretical preload of the first bearing 121.

[0136] Furthermore, the second preload parameters include the theoretical preload of the second bearing 122, the axial clearance elongation between the second housing 112 and the second bearing 122, the radial clearance elongation between the second housing 112 and the second bearing 122, and the axial deformation of the second bearing 122 under the theoretical preload of the second bearing 122.

[0137] It should be noted that the theoretical preload of the bearing can be obtained using gear system analysis software such as MASTA, Kisssoft, or ROMAX. A curve showing the relationship between bearing life and theoretical preload is available for reference. Figure 3 S A The corresponding bearing preload is the theoretical preload.

[0138] The axial clearance elongation between the first housing 111 and the first bearing 121, and the axial clearance elongation between the second housing 112 and the second bearing 122, respectively refer to the elongation of the axial clearance between the first housing 111 and the first bearing 121, and between the second housing 112 and the second bearing 122, caused by the difference in their coefficients of thermal expansion in the axial direction. The specific calculation method can refer to existing technology. In this embodiment, the sum of the axial clearance elongation between the first housing 111 and the first bearing 121, and the axial clearance elongation between the second housing 112 and the second bearing 122, can be calculated based on the material thermal expansion coefficient C2 of the housing, the thermal expansion coefficient C1 of the bearing, the temperature difference between the housing and the bearing, and the distance Ls between the outer rings of the first bearing 121 and the second bearing 122, according to formula S. T1 = (L*C2*Δt2)-(L*C1*Δt1) is calculated. Of course, those skilled in the art can also choose other methods to calculate the axial clearance elongation between the first housing 111 and the first bearing 121, and the axial clearance elongation between the second housing 112 and the second bearing 122, and this embodiment does not limit this.

[0139] The radial clearance elongation between the first housing 111 and the first bearing 121, and the radial clearance elongation between the second housing 112 and the second bearing 122, respectively refer to the deformation of the first housing 111 and the first bearing 121, and the second housing 112 and the second bearing 122 caused by the different coefficients of radial expansion of the first housing 111 and the first bearing 121, and the second housing 112 and the second bearing 122, and are ultimately converted into the elongation of the axial clearance between the first housing 111 and the first bearing 121, and the second housing 112 and the second bearing 122. The specific calculation method can refer to existing technology. In this embodiment, the radial clearance elongation between the first housing 111 and the first bearing 121 can be calculated based on the calculation coefficient Y1 of the first bearing, the calculation coefficient Y2 of the second bearing, the relative displacement caused by the radial expansion of the first housing 111 and the first bearing 121, and the relative displacement caused by the radial expansion of the second housing 112 and the second bearing 122, using formula S. T2 = (Y1 / 0.8*ΔQ1+Y2 / 0.8*ΔQ2) is calculated. Of course, those skilled in the art can also choose other methods to calculate the radial clearance elongation between the first housing 111 and the first bearing 121, and the radial clearance elongation between the second housing 112 and the second bearing 122, and this embodiment does not limit this.

[0140] The axial deformation of the first bearing 121 and the axial deformation of the second bearing 122 under the theoretical preload refer to the axial deformation that occurs under the theoretical preload, because the first housing 111 and the first bearing 121, as well as the second housing 112 and the second bearing 122, are not ideal rigid bodies. This deformation is calculated using the formula b = A1 / K based on the axial stiffness values ​​of the first bearing 121 and the second bearing 122; where b is the axial deformation, A1 is the preload value obtained from a table based on the sum of the displacement changes of the first bearing 121 and the second bearing 122, derived from a preset displacement change-preload relationship, and K is the axial stiffness value of the housing assembly, and K = 1 / (1 / K1 + 1 / K2); where K1 is the axial stiffness value of the first bearing 121 and K2 is the axial stiffness value of the second bearing 122. Of course, those skilled in the art may also choose other methods to calculate the axial deformation of the first bearing 121 under the theoretical preload of the first bearing 121 and the axial deformation of the second bearing 122 under the theoretical preload of the second bearing 122, and this embodiment does not limit this.

[0141] Further, in step S3, the preload between the bearing assembly and the housing assembly is determined according to the following formula:

[0142] S = S0 - S 11 -S 12 +S A +ST1 +S T2 +S K

[0143] Alternatively, the preload between the bearing assembly and the housing assembly can be determined using the following formula:

[0144] S = S0 - S′ 11 -S′ 12 +S A +S T1 +S T2 +S K

[0145] Where S is the preload between the bearing assembly and the housing assembly, and S0 is the clearance between the housing assembly and the bearing assembly. 11 S′ 11 For the first elongation, S 12 S′ 12 This is the second elongation.

[0146] S A =S A1 +S A2 S A1 S is the theoretical preload of the first bearing. A2 This is the theoretical preload of the second bearing.

[0147] S T1 =S T11 +S T12, S T11 S is the axial clearance elongation between the first housing and the first bearing. T12, This refers to the axial clearance elongation between the second housing and the second bearing.

[0148] S T2 =S T21 +S T22 S T21 S is the radial clearance elongation between the first housing and the first bearing. T22 This refers to the radial clearance elongation between the second housing and the second bearing.

[0149] S K =S K1 +S K2 S K1 S represents the axial deformation of the first bearing under its theoretical preload; K2 This refers to the axial deformation of the second bearing under the theoretical preload of the second bearing.

[0150] It should be noted that, in this embodiment, S T1 and S T2 The value can be positive or negative.

[0151] It should also be noted that, because the first bearing 121 and the second bearing 122 are mounted at both ends of the same shaft system, S A1 and S A2 These two parameters are related, so S A1 and S A2 It may not be the optimal preload for each bearing; it can only maximize the lifespan of both bearings.

[0152] The above method for calculating the preload takes into account the axial elongation of the first bearing and the axial elongation of the second bearing caused by the interference fit of the shaft hole between the bearing assembly and the housing assembly, so that the calculated preload will not be too large.

[0153] Preferably, in this embodiment, after step S3, the following steps are further included: determining the thickness of the gasket between the first bearing and the first housing, and the thickness of the gasket between the second bearing and the second housing, based on the preload between the bearing assembly and the housing assembly.

[0154] In other words, once the appropriate preload is determined, a suitable shim can be selected based on that preload. It should be noted that the effects of temperature and the stiffness of the gearbox tapered bearing system should be considered when selecting shims. This ensures that the selected shims are not too tight, maximizing the performance potential and lifespan of the bearing assembly.

[0155] In another specific embodiment of the present invention, a method for calculating the bearing assembly preload is provided, wherein the bearing assembly preload is calculated using the following formula:

[0156] S = S0 - S1 + S A +S T1 +S T2 +S K

[0157] Where S represents the bearing assembly preload.

[0158] S0 represents the gap between the depth of housing assembly 11 and the first bearing 121 and the second bearing 122, which is the difference between the sum of the depths of the two housings and the distance between the large end faces of the outer rings of the two bearings. The specific calculation formula is as follows:

[0159] S0 = L c 1+L c 2-Ls

[0160] Among them, L c1 L is the first depth of the first shell 111. c2 Ls is the second depth of the second housing 112, and Ls is the total length of the bearing assembly 12.

[0161] S1 is the axial elongation calculated based on the interference fit between the bearing assembly 12 and the housing assembly 11, which can be calculated using elasticity mechanics and computational analysis. Specifically, the formula for calculating S1 is:

[0162] S1=S 11 +S 12

[0163] Among them, S 11 This refers to the axial elongation of the first bearing 121 under the theoretical preload, which is also the elongation of the first bearing. The calculation formula is as follows:

[0164] S 11 =ΔR1*Cot(θ1)+ΔA1

[0165] ΔR1 is the radial deformation of the first bearing 121 under the interference fit between the first housing 111 and the first bearing 121; θ1 is the semi-cone angle of the inner raceway of the outer ring of the first bearing 121; ΔA1 is the axial deformation of the first bearing 121 under the interference fit between the first housing 111 and the first bearing 121.

[0166] S 12 The axial elongation of the second bearing 122 under the theoretical preload, i.e., the elongation of the second bearing, is calculated using the following formula:

[0167] S 12 =ΔR2*Cot(θ2)+ΔA2

[0168] ΔR2 is the radial deformation of the second bearing 122 under the interference fit of the second housing 112 and the second bearing 122; θ2 is the semi-cone angle of the inner raceway of the outer ring of the second bearing 122; ΔA1 is the axial deformation of the second bearing 122 under the interference fit of the second housing 112 and the second bearing 122.

[0169] In the actual selection of pads, it is impossible to calculate S separately for each different interference amount. 11 and S 12 Therefore, it is necessary to use the results of Computer-Aided Engineering (CAE) to transform S 11 and S 12 The formula has been simplified. The simplified calculation formula is as follows:

[0170]

[0171] D b1 D b2 These represent the outer diameters of the outer rings of the first bearing 121 and the second bearing 122, respectively; D c1 D c2The diameters of the mounting holes in the first housing 111 and the second housing 112 are respectively represented; C1 and b1 are the calculated coefficients and constants of the first bearing 121 obtained by computer-aided engineering and linear regression method according to the calculation formula before simplification; C2 and b2 are the calculated coefficients and constants of the second bearing 122 obtained by computer-aided engineering and linear regression method according to the calculation formula before simplification.

[0172] S A This is the theoretical preload of the bearing assembly 12.

[0173] S T1 This refers to the elongation of the axial clearance between the tapered bearing and the housing assembly 11 due to the difference in their coefficients of expansion in the axial direction.

[0174] S T2 This refers to the elongation caused by the radial deformation of the housing assembly 11 and the bearing assembly 12 due to their different coefficients of thermal expansion, which ultimately translates into the axial clearance between the tapered bearing and the housing assembly 11.

[0175] S K Because the housing assembly 11 and the bearing assembly 12 are not ideal rigid bodies, they are in S A Axial deformation occurring under theoretical preload.

[0176] The bearing assembly preload calculation method provided by this invention comprehensively considers the theoretical preload S required for the tapered bearing at its theoretical maximum lifespan. A The relationship between the radial interference fit between the tapered bearing and the housing and the axial elongation of the tapered bearing (S) I Axial deformation S of tapered bearings and housings at different temperatures T1 And the radial deformation converted to the axial deformation S T2 and in the theoretical preload S A Axial elongation S of the lower tapered bearing and housing K This allows for precise selection of the shim with the optimal preload S, maximizing the utilization potential of the tapered bearing. This, in turn, enables the miniaturization of the gearbox tapered bearing and the overall gearbox design.

[0177] Using the above method, the required preload for bearing assembly can be calculated more accurately. Selecting appropriate shims based on this preload ensures the bearing assembly operates under optimized preload force, unlocking its full potential. Research on a mass-produced transmission shows that using shims selected using this method in the transmission's tapered bearing system can increase the bearing assembly's lifespan by 15%-25%.

[0178] It should be noted that although this invention addresses the shim selection for gearbox tapered bearing systems, the method described herein can also be applied to other bearings with axially asymmetric raceway structures, such as angular contact ball bearings. Therefore, if a bearing with an axially asymmetric raceway structure uses the shim selection method described herein, it remains within the scope of protection of this invention.

[0179] While the present invention has been illustrated and described with reference to certain preferred embodiments, those skilled in the art should understand that the above description is a further detailed explanation of the invention in conjunction with specific embodiments, and should not be construed as limiting the specific implementation of the invention to these descriptions. Various changes in form and detail can be made by those skilled in the art, including several simple deductions or substitutions, without departing from the spirit and scope of the invention.

Claims

1. A method for calculating bearing assembly preload, characterized in that, Suitable for gearbox tapered bearing systems; The gearbox tapered bearing system includes: A housing assembly, the housing assembly including a first housing and a second housing, the first housing and the second housing being spaced apart in the axial direction of the housing assembly; A bearing assembly includes a first bearing, a second bearing, and a shaft. The first bearing and the second bearing are respectively disposed at both ends of the shaft. The bearing assembly is disposed between a first housing and a second housing, and the axial direction of the bearing assembly coincides with the axial direction of the housing assembly. The method for calculating the bearing assembly preload includes the following steps: S1: Obtain the interference parameters of the gearbox tapered bearing system, and calculate the first elongation of the first bearing and the second elongation of the second bearing based on the interference parameters; S2: Obtain the axial parameters of the gearbox tapered bearing system, and calculate the clearance value between the housing assembly and the bearing assembly based on the axial parameters; S3: Obtain the first preload parameter of the first bearing and the second preload parameter of the second bearing, and determine the preload amount between the bearing assembly and the housing assembly based on the first preload parameter, the first elongation, the second preload parameter, the second elongation, and the clearance value; In step S3, the first preload parameter includes the theoretical preload of the first bearing, the axial clearance elongation between the first housing and the first bearing, the radial clearance elongation between the first housing and the first bearing, and the axial deformation of the first bearing under the theoretical preload of the first bearing. The second preload parameters include the theoretical preload of the second bearing, the axial clearance elongation between the second housing and the second bearing, the radial clearance elongation between the second housing and the second bearing, and the axial deformation of the second bearing under the theoretical preload of the second bearing; and In step S3, the preload between the bearing assembly and the housing assembly is determined according to the following formula: S=S0-S 11 -S 12 +S A +S T1 +S T2 +S K Alternatively, the preload between the bearing assembly and the housing assembly can be determined using the following formula: S=S0-S′ 11 -S′ 12 +S A +S T1 +S T2 +S K Wherein, S is the preload between the bearing assembly and the housing assembly, S0 is the clearance between the housing assembly and the bearing assembly, and S... 11 S′ 11 S is the first elongation. 12 S′ 12 S is the second elongation. A S represents the theoretical preload of the bearing assembly. T1 S is the elongation of the axial clearance between the bearing assembly and the housing assembly caused by the difference in their coefficients of thermal expansion in the axial direction due to the housing assembly and the shaft system. T2 S is the elongation caused by the radial deformation of the housing assembly and shaft system due to their different coefficients of thermal expansion, which ultimately translates into the axial clearance between the bearing assembly and the housing assembly. K This refers to the axial deformation of the housing assembly and shaft system under the theoretical preload.

2. The method for calculating bearing assembly preload as described in claim 1, characterized in that, In step S1, the interference parameters include the outer diameter of the outer ring of the first bearing, the outer diameter of the outer ring of the second bearing, the diameter of the mounting hole of the first housing for mounting the first bearing, and the diameter of the mounting hole of the second housing for mounting the second bearing; and Step S1 includes: Obtain the first calculation parameters of the first bearing, and calculate the first elongation based on the outer diameter of the outer ring of the first bearing, the bore diameter of the first housing, and the first calculation parameters; Obtain the second calculation parameters of the second bearing, and calculate the second elongation based on the outer diameter of the outer ring of the second bearing, the bore diameter of the second housing, and the second calculation parameters.

3. The method for calculating bearing assembly preload as described in claim 2, characterized in that, The first calculation parameters include a first bearing coefficient and a first bearing constant; the second calculation parameters include a second bearing coefficient and a second bearing constant; and The first elongation is calculated using the following formula: S 11 =C1*(D b1 -D c1 )+b1 Among them, S 11 C1 is the first elongation, D is the first bearing coefficient, and C1 is the first bearing coefficient. b1 D is the outer diameter of the outer ring of the first bearing. c1 Let b1 be the aperture of the first housing, and b1 be the constant of the first bearing; and The second elongation is calculated using the following formula: S 12 =C2*(D b2 -D c2 )+b2 Among them, S 12 C2 is the second elongation, and D is the second bearing coefficient. b2 D is the outer diameter of the outer ring of the second bearing. c2 b1 is the aperture of the second housing, and b2 is the constant of the second bearing.

4. The method for calculating bearing assembly preload as described in claim 3, characterized in that, The first calculation parameter for obtaining the first bearing includes: Obtain the first radial deformation of the first bearing, the first axial deformation of the first bearing, and the half-cone angle of the inner raceway of the first outer ring of the first bearing; The formula for calculating the elongation of the first bearing is determined based on the first radial deformation, the first axial deformation, and the half-cone angle of the inner raceway of the first outer ring. The first calculation parameters are determined based on the elongation calculation formula of the first bearing, using linear regression and computer-aided engineering. The process of obtaining the second calculation parameter of the second bearing includes: Obtain the second radial deformation of the second bearing, the second axial deformation of the second bearing, and the half-cone angle of the inner raceway of the second outer ring of the second bearing; The formula for calculating the elongation of the second bearing is determined based on the second radial deformation, the second axial deformation, and the half-cone angle of the inner raceway of the second outer ring. The second calculation parameter is determined based on the elongation calculation formula of the second bearing and using linear regression and computer-aided engineering.

5. The method for calculating bearing assembly preload as described in claim 4, characterized in that, The formula for calculating the elongation of the first bearing is: S 11’ =ΔR1*Cot(θ1)+ΔA1 Among them, S 11’ Let ΔR1 be the elongation of the first bearing, θ1 be the first radial deformation, θ1 be the semi-cone angle of the inner raceway of the first outer ring, and ΔA1 be the first axial deformation; and The formula for calculating the elongation of the second bearing is: S 12’ =ΔR2*Cot(θ2)+ΔA2 Among them, S 12’ ΔR2 is the elongation of the second bearing, θ2 is the second radial deformation, θ2 is the semi-cone angle of the inner raceway of the second outer ring, and ΔA2 is the second axial deformation.

6. The method for calculating bearing assembly preload as described in claim 1, characterized in that, The interference parameters include the first radial deformation of the first bearing, the second radial deformation of the second bearing, the first axial deformation of the first bearing, the second axial deformation of the second bearing, the semi-cone angle of the inner raceway of the first outer ring of the first bearing, and the semi-cone angle of the inner raceway of the second outer ring of the second bearing; and Step S1 includes: The first elongation is calculated based on the first radial deformation, the first axial deformation, and the half-cone angle of the inner raceway of the first outer ring; The second elongation is calculated based on the second radial deformation, the second axial deformation, and the half-cone angle of the inner raceway of the second outer ring.

7. The method for calculating bearing assembly preload as described in claim 6, characterized in that, The first elongation is calculated using the following formula: S 11 ’=ΔR1*Cot(θ1)+ΔA1 Among them, S 11 ' is the first elongation, ΔR1 is the first radial deformation, θ1 is the semi-cone angle of the inner raceway of the first outer ring, and ΔA1 is the first axial deformation; and The second elongation is calculated using the following formula: S 12 ’=ΔR2*Cot(θ2)+ΔA2 Among them, S 12 ' represents the second elongation, ΔR2 represents the second radial deformation, θ2 represents the semi-cone angle of the inner raceway of the second outer ring, and ΔA2 represents the second axial deformation.

8. The method for calculating bearing assembly preload as described in claim 1, characterized in that, In step S2, the axial parameters include the first depth of the first housing, the second depth of the second housing, and the total length of the first bearing and the second bearing in the axial direction of the bearing assembly; and In step S2, the clearance value between the housing assembly and the bearing assembly is calculated according to the following formula: S0=L c1 +L c2 -L s Where S0 is the gap value, L c1 For the first depth, L c2 For the second depth, L s The total length of the first bearing and the second bearing in the axial direction of the bearing assembly.

9. The method for calculating bearing assembly preload as described in claim 1, characterized in that, S A =S A1 +S A2 S A1 S is the theoretical preload of the first bearing. A2 This is the theoretical preload of the second bearing. S T1 =S T11 +S T12 S T11 S is the axial clearance elongation between the first housing and the first bearing. T12 This refers to the axial clearance elongation between the second housing and the second bearing. S T2 =S T21 +S T22 S T21 S is the radial clearance elongation between the first housing and the first bearing. T22 This refers to the radial clearance elongation between the second housing and the second bearing. S K =S K1 +S K2 S K1 S represents the axial deformation of the first bearing under its theoretical preload; K2 This refers to the axial deformation of the second bearing under its theoretical preload.

10. The method for calculating bearing assembly preload as described in claim 1, characterized in that, After step S3, the method further includes: The thickness of the shim between the first bearing and the first housing, and the thickness of the shim between the second bearing and the second housing, are determined based on the preload between the bearing assembly and the housing assembly.

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