A design method for the crossbeam of the cage of a planetary needle roller bearing

Abstract

The present invention belongs to the technical field of computer-aided design of bearings, and proposes a design method for the cross beam of the planet needle bearing cage. The steps are as follows: taking the intersection point of the center line of the pocket of the cross beam of the cage and the center line of the cage as the origin, taking the axial direction of the cage as the y-axis, and the circumferential direction of the cage as the x-axis, a coordinate system is established; setting the half-width of the pocket of the cross beam of the cage to be designed along the y-axis b e and the half-width of the pocket along the x-axis b s ; for the root modification profile of the cross beam of the cage, five points P0, P1, P2, P3, and P4 are set; taking P0, P1, P2, P3, and P4 as the five points describing the Bessel curve, the expression of the root modification profile is obtained; a parameter optimization algorithm is used to obtain the optimal design parameters of the root modification profile, and the design of the cross beam of the cage is completed. The present invention can relieve the stress concentration at the corner position of the cross beam of the cage as much as possible in a limited space, thereby effectively reducing the fracture risk of the cross beam of the cage.

Description

Technical Field

[0001] The invention belongs to the technical field of computer-aided design of bearings, and in particular relates to a design method for a planetary needle roller bearing cage crossbeam. Background Art

[0002] Planetary needle roller bearings are used to support planetary gears on planetary carriers in planetary gear transmissions and are a very important component. With the development trend of high-speed and heavy-load transmissions, planetary needle roller bearing cage beam fractures are becoming more and more common, posing a great hidden danger to the reliable operation of transmissions. The location where the cage beam fractures generally occurs at the corner where it transitions with the crossbeam. Due to space limitations, the existing technology requires manufacturers to select a fillet radius to process the corner based on their own experience, which can easily cause severe stress concentration, thereby significantly increasing the risk of cage fracture failure. Therefore, there is an urgent need for an optimization design method for planetary needle roller bearing cage beams to reduce the risk of cage beam fracture failure. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention proposes a design method for a planetary needle roller bearing cage beam, which can quickly design the corner shape of the cage beam and the crossbeam so that the cage beam has good strength and can reduce the risk of cage beam breakage.

[0004] The technical solution of the present invention is as follows:

[0005] A design method for a planetary needle roller bearing cage crossbeam comprises the following steps:

[0006] Step S1: Establish a coordinate system with the intersection of the centerline of the cage pocket and the centerline of the cage as the origin, the axial direction of the cage as the y-axis, and the circumferential direction of the cage as the x-axis;

[0007] Step S2: Set the half width of the pocket of the cage to be designed along the y-axis direction b e and the half width of the pocket along the x-axis b s ;

[0008] Step S3: for the root modification profile of the cage beam, five points P0, P1, P2, P3 and P4 are set, wherein P0 represents the intersection of the root modification profile and the cage beam, P4 represents the intersection of the root modification profile and the cage beam, P1 represents a point on the extension line of P0 along the x-axis, P3 represents a point on the extension line of P4 along the y-axis, and P2 represents an intermediate control point, the position of which is associated with the standard fillet of the root of the cage beam;

[0009] Step S4: Taking P0, P1, P2, P3 and P4 as five points describing the Bezier curve, the expression of the root shaping contour is obtained:

[0010]

[0011] in, Table Bezier curve function, , t Represents the Bezier curve coefficient;

[0012] Step S5: With the goal of meeting the strength requirements of the cage, a parameter optimization algorithm is used to obtain the optimal design parameters of the root modification profile to complete the design of the cage crossbeam.

[0013] Preferably, in step S3, the coordinates of P0 are [ , ], are the design parameters of the root shaping profile, is the fillet radius of the bearing roller end face.

[0014] Preferably, in step S3, the coordinates of P1 are [ , ], Design parameters for the root shaping profile.

[0015] Preferably, in step S3, the coordinates of P2 are [ , ], , Design parameters for root shaping profile.

[0016] Preferably, in step S3, the coordinates of P3 are [ , ], , Design parameters for the root shaping profile.

[0017] Preferably, in step S3, the coordinates of P4 are [ , ].

[0018] Preferably, the strength index of the parameter optimization algorithm in step S5 is , the expression is as follows:

[0019]

[0020] in, Indicates any point on the root modification contour j The coordinates of Indicates the position where the impact force of the bearing roller acts yAxis coordinates, Indicates the half width of the pocket along the x-axis b s and half width of cage beam, Indicate point j The radius of curvature.

[0021] Preferably, the parameter optimization algorithm in step S5 is a particle swarm algorithm or a genetic algorithm.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The design method of the planetary needle roller bearing cage beam proposed in the present invention can alleviate the stress concentration at the corner position of the cage beam as much as possible within a limited space, thereby effectively reducing the risk of fracture of the cage beam.

[0024] 2. The design method of the planetary needle roller bearing cage crossbeam proposed in the present invention can adapt to the optimized design of the planetary needle roller bearing cage under the compact space requirements through the five points P0, P1, P2, P3, and P4 of the Bezier curve, while fully improving the strength of the cage crossbeam and taking into account the design efficiency. The Bezier curve used has the characteristics of smooth curvature changes, which is particularly suitable for the situation where the space of the planetary needle roller bearing cage pocket and corner position is limited. It can only use the Bezier curve integrated design, thereby avoiding the design form of multiple curve combinations.

[0025] 3. The design method of the planetary needle roller bearing cage crossbeam proposed in the present invention introduces strength index in the process of parameter optimization , the influence of section inertia moment and curvature radius on stress concentration based on bending deformation is considered, and the optimization result has high credibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. The features and advantages of the present invention can be more clearly understood by referring to the drawings. The drawings are schematic and should not be understood as limiting the present invention in any way. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 It is a flow chart of the design method of the planetary needle roller bearing cage crossbeam proposed by the present invention.

[0028] Figure 2 It is a schematic diagram of the design method of the planetary needle roller bearing cage crossbeam proposed by the present invention.

[0029] Figure 3This is the modified profile obtained in Example 1.

[0030] Figure 4 is the curvature of the modified profile obtained in Example 1. DETAILED DESCRIPTION

[0031] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0032] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0033] like Figure 1-2 As shown in the figure, the solid line represents the standard fillet of the root of the planetary needle roller bearing cage beam, and the dotted line represents the modified root profile of the planetary needle roller bearing cage beam. In order to accurately describe the modified root profile, a coordinate system is established with the intersection of the pocket centerline and the cage centerline as the origin, the cage axial direction as the y-axis, and the cage circumferential direction as the x-axis.

[0034] On this basis, the root modification profile of the cage beam is designed based on the Bezier curve of 5 points, where P0 and P4 represent the starting positions of the root modification profile, P1, P2 and P3 are the control points of the root modification profile, and different root modification profiles of the cage beam can be obtained by adjusting the positions of the 5 points.

[0035] The distance between the starting point P0 of the root modification profile on the cage lintel and the y-axis is The distance between the starting point P4 of the root modification profile on the cage beam and the x-axis is ;

[0036] The positions of P1 and P3 are on the extension lines of the cage beam and cage crossbeam respectively, and the distance between P0 and P1 is , the distance between P3 and P4 is ,in r g is the standard fillet radius of the root of the cage beam, b e is the half width of the cage pocket along the y-axis direction, z 1 and z 4 is the design parameter of the root modification profile.

[0037] The position of the intermediate control point P2 is determined by the design parameters z 2 and z3 and the center point of the standard fillet at the root of the cage beam is determined.

[0038] Therefore, the coordinates of the five points describing the Bezier curve are:

[0039]

[0040] in, b s is the half width of the pocket along the x-axis, is the design parameter vector of the root modification profile.

[0041] like Figure 2 As shown, after the above design system is established, the following steps are performed to complete the design of the planetary needle roller bearing cage beam.

[0042] (1) First, set the half width of the pocket of the cage to be designed along the y-axis direction b e and the half width of the pocket along the x-axis b s .

[0043] (2) According to the definition equation of the Bezier curve, the expression of the root shaping contour can be obtained:

[0044]

[0045] in, t is the Bezier curve coefficient, and its value is 0≤t≤1.

[0046] (3) Obtain the optimal values ​​of the root modification contour design parameters through parameter optimization algorithms (particle swarm optimization, genetic algorithm, etc.). The strength index F of the optimization process e :

[0047]

[0048] in, Indicates any point on the root modification contour j The coordinates of Indicates the position where the impact force of the bearing roller acts y Axis coordinates, Indicates the half width of the pocket along the x-axis b s and half width of cage beam, Indicate point j The radius of curvature.

[0049] Strength index F e It can be used to characterize the maximum stress at the root of the cage beam. The smaller the value, the higher the strength of the cage.

[0050] (4) According to the optimal values ​​of the root modification profile design parameters obtained by optimization, the corresponding corner profile shape of the cage beam root can be obtained.

[0051] Example 1

[0052] Taking the K38×46×32 planetary needle roller bearing as an example, the original design of the bearing roller end face fillet radius r g The optimal design parameters obtained by using the design method of the planetary needle roller bearing cage crossbeam of the present invention are . We can further get the positions of the five points and the corresponding contours. The shapes before and after optimization are as follows: Figure 3 As shown, the curvature is Figure 4 As shown, the solid line represents the optimized shape and the dotted line represents the shape before optimization. The results show that the optimized contour will remove the material at the root of the cage beam. From the perspective of curvature, the curvature before optimization is 5.55mm -1 The maximum curvature after optimization is only 2.94mm -1 , the average value is 1.29mm -1 , and the curvature changes smoothly, which can significantly reduce local stress concentration.

[0053] The rigid-flexible coupling dynamic model of the planetary needle roller bearing is established, in which the cage is a flexible body. The dynamic model before and after optimization uses the same settings. The maximum stress on the cage beam before and after optimization is 52.76MPa and 40.12MPa, respectively, indicating that the design method of the present invention can increase the strength of the cage by 23.96%. The strain at the root of the cage beam is collected through physical tests, and it is found that the maximum strain before and after optimization is 262.32×10 -6 and 195.33×10 -6 , the measured cage strength can be increased by 25.5%. Therefore, both simulation and experiment show that the present invention has a significant technical effect of increasing the cage strength of planetary needle roller bearings.

[0054] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0055] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0056] In the present invention, the terms "first", "second", "third", "fourth" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. The term "plurality" refers to two or more, unless otherwise clearly defined.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A design method for a planetary needle roller bearing cage beam, characterized in that: The following steps are involved: Step S1: Establish a coordinate system with the intersection of the centerline of the cage pocket and the centerline of the cage as the origin, the axial direction of the cage as the y-axis, and the circumferential direction of the cage as the x-axis; Step S2: Set the half width of the pocket of the cage to be designed along the y-axis direction b e and the half width of the pocket along the x-axis b s ; Step S3: for the root modification profile of the cage beam, five points P0, P1, P2, P3 and P4 are set, wherein P0 represents the intersection of the root modification profile and the cage beam, P4 represents the intersection of the root modification profile and the cage beam, P1 represents a point on the extension line of P0 along the x-axis, P3 represents a point on the extension line of P4 along the y-axis, and P2 represents an intermediate control point, the position of which is associated with the standard fillet of the root of the cage beam; Step S4: Taking P0, P1, P2, P3 and P4 as five points describing the Bezier curve, the expression of the root shaping contour is obtained: in, represents the Bezier curve function, , t Represents the Bezier curve coefficient; Step S5: With the goal of meeting the strength requirements of the cage, a parameter optimization algorithm is used to obtain the optimal design parameters of the root modification profile to complete the design of the cage crossbeam.

2. The design method of the planetary needle roller bearing cage crossbeam according to claim 1, characterized in that: In step S3, the coordinates of P0 are [ , ], are the design parameters of the root shaping profile, is the fillet radius of the bearing roller end face.

3. The design method of the planetary needle roller bearing cage crossbeam according to claim 2, characterized in that: In step S3, the coordinates of P1 are [ , ], Design parameters for the root shaping profile.

4. The design method of the planetary needle roller bearing cage crossbeam according to claim 3, characterized in that: In step S3, the coordinates of P2 are [ , ], , Design parameters for the root shaping profile.

5. The design method of the planetary needle roller bearing cage crossbeam according to claim 4, characterized in that: In step S3, the coordinates of P3 are [ , ], , Design parameters for the root shaping profile.

6. The design method of the planetary needle roller bearing cage crossbeam according to claim 5, characterized in that: In step S3, the coordinates of P4 are [ , ].

7. The design method of the planetary needle roller bearing cage crossbeam according to claim 6, characterized in that: The strength index of the parameter optimization algorithm in step S5 is , the expression is as follows: in, Indicates any point on the root modification contour j The coordinates of Indicates the position where the impact force of the bearing roller acts y Axis coordinates, Indicates the half width of the pocket along the x-axis b s and half width of cage beam, Indicate point j The radius of curvature.

8. The design method of the planetary needle roller bearing cage crossbeam according to claim 7, characterized in that: The parameter optimization algorithm in step S5 is a particle swarm algorithm or a genetic algorithm.

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