A maintenance-free uniformly loaded planetary roller screw and implementation method thereof

Abstract

The present invention relates to a non-modified and evenly loaded planetary roller screw and an implementation method thereof, which is composed of a nut, a screw, a roller, an inner gear ring, a planet carrier and an elastic retaining ring, wherein the pitch values ​​of the nut and the roller are obtained by a proposed evenly loaded design method. The evenly loaded design method comprises establishing an equal load distribution force matrix; establishing a planetary roller screw thread tooth load distribution calculation model according to the deformation coordination equation and load balance equation of two adjacent thread teeth on the contact side of the roller-screw and the nut-roller; obtaining the design pitch of the roller and the nut based on the planetary roller screw thread tooth load distribution calculation model and the equal load distribution force matrix; and using the roller and nut design pitch for the design and processing and manufacturing of rollers and nuts of the evenly loaded planetary roller screw. The present invention can realize the uniform distribution of the load of the planetary roller screw, and the constant pitch design eliminates the complicated thread tooth modification processing, which greatly improves the load performance of the planetary roller screw while reducing the processing and manufacturing costs.

Description

Technical Field

[0001] The invention belongs to the technical field of planetary roller screws, and in particular relates to a maintenance-free, uniformly loaded planetary roller screw and a realization method thereof. Background Art

[0002] The planetary roller screw is a basic component that can convert rotational motion into linear motion. Due to its advantages such as strong load-bearing capacity, fast response speed, high positioning accuracy and long life, it is replacing traditional hydraulic transmission and ball screw transmission and is widely used in semiconductor equipment, CNC machine tools, robots, aerospace and other fields.

[0003] The planetary roller screw is composed of a nut, roller, screw, cage and internal gear, and transmits motion and power through the meshing of the threads. Due to the complex deformation coordination relationship between the roller-screw and nut-roller contact sides, the thread load distribution shows strong unevenness. The uneven distribution of thread load leads to lubrication failure at the position with large contact load, aggravated friction and wear, and increased probability of fatigue failure, which seriously affects the service performance of the planetary roller screw. In order to effectively reduce the maximum load of the planetary roller screw thread contact, it is of great significance to design the uniformity of the thread load distribution.

[0004] However, the current load-balancing design for planetary roller screws requires complex shaping of the thread teeth, which is difficult to manufacture and has high production costs. In addition, the current load-balancing designs for the roller-screw side and the nut-roller side of planetary roller screws are mostly independent, and the design method is relatively complex, relying on many design variables, and is difficult to implement.

[0005] Therefore, how to improve the existing planetary roller screw to achieve maintenance-free and load-balanced planetary roller screw is a technical problem that urgently needs to be solved. Summary of the invention

[0006] The object of the present invention is to provide a planetary roller screw with no maintenance and equal load and an implementation method, so as to realize the planetary roller screw with no maintenance and equal load.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0008] In a first aspect, a method for realizing a maintenance-free uniformly loaded planetary roller screw is provided, comprising the following steps:

[0009] S1: Set the pitch of the roller and nut as the design parameter to be determined, the pitch of the screw as a known given parameter, and assume that the thread teeth on the contact side of the roller-screw and nut-roller are ideally distributed with equal loads, thereby establishing the equal load distribution force matrix F;

[0010] S2: Based on the deformation coordination relationship between two adjacent threads on the roller-screw and nut-roller contact sides, a deformation coordination equation is established, and combined with the roller-screw and nut-roller contact side load and external load balance equation, a planetary roller screw thread load distribution calculation model is established;

[0011] S3: The roller and nut pitch gradient is calculated based on the planetary roller screw thread load distribution calculation model and the equal load distribution force matrix. P Ri and P Ni , calculate the average value of the gradient pitch to get the design pitch of the roller and nut PD R and PD N ;

[0012] S4: Design the pitch of the roller and nut PD R and PD N Used for the design, processing and manufacture of rollers and nuts for evenly loaded planetary roller screws.

[0013] Preferably, the equal load distribution force matrix F established in step S1 is 2n×1 :

[0014] ;

[0015] in, F RS represents the axial contact load on the roller-screw contact side, F NR is the axial contact load on the nut-roller contact side, and the subscript following it indicates the corresponding thread number. n is the number of roller thread teeth, z is the number of rollers, F 0 is external load.

[0016] Preferably, in step S2, the deformation coordination equation expression established according to the deformation coordination relationship between two adjacent threads on the contact side of the roller-screw and the nut-roller is:

[0017] ;

[0018] ;

[0019] in, i The thread number, j is the cumulative lower bound. F RS represents the axial contact load on the roller-screw contact side, F NRis the axial contact load on the nut-roller contact side, and the subscript following it indicates the corresponding thread number. k RSC and k NRC are the axial contact stiffness of the roller-screw and nut-roller sides, respectively, and the subscripts behind them indicate the corresponding thread number; k RA , k SA and k NA Respectively represent the shaft segment stiffness of the roller, screw and nut, followed by the subscript indicating the corresponding thread number; k RT , k ST and k NT They represent the thread stiffness of the roller, screw and nut respectively, and the subscripts after them represent the corresponding thread numbers; the axial contact stiffness, shaft segment stiffness and thread stiffness are calculated according to the corresponding calculation formulas based on the given design parameters; P R , P S and P N They represent the pitch between adjacent threads of the roller, screw and nut respectively, and the subscripts following them represent the corresponding thread numbers.

[0020] Preferably, an expression for the roller-screw and nut-roller contact side load and external load balance equation is established:

[0021] ;

[0022] in, n is the number of roller thread teeth, n is a positive integer, F 2n×1 is the uniform load distribution force matrix, z is the number of rollers, F 0 is external load.

[0023] Preferably, according to the deformation coordination equation established based on the deformation coordination relationship between two adjacent threads on the contact side of the roller-screw and the nut-roller, and the load and external load balance equation on the contact side of the roller-screw and the nut-roller, a group of equations is formed and converted into a matrix form to establish the planetary roller screw thread load distribution calculation model. The expression of the planetary roller screw thread load distribution calculation model is as follows:

[0024] .

[0025] in, n is the number of roller thread teeth, nis a positive integer, A 2n×2n represents the matrix composed of stiffness, F 2n×1 represents the uniform load distribution force matrix, z is the number of rollers, F 0 is external load, P R , P S and P N They represent the pitch between adjacent threads of the roller, screw and nut respectively, and the subscripts following them represent the corresponding thread numbers.

[0026] Preferably, the known equal load distribution force matrix F is substituted into the expression of the planetary roller screw thread load distribution calculation model, and the gradual pitch value of the roller and the nut is obtained by solving P Ri and P Ni ,in i ∈[1, n -1], and then the average value of the gradient pitch is calculated to obtain the design pitch of the roller and nut PD R and PD N , whose expression is:

[0027] .

[0028] Preferably, in step S4, the design pitch is used for the design and manufacturing of rollers and nuts. Since the design pitch of rollers and nuts is a constant value, there is no need to perform profiling on the thread teeth, so a planetary roller screw that is free of profiling and meets the requirements of uniform load distribution can be achieved.

[0029] In the second aspect, a maintenance-free and evenly loaded planetary roller screw is provided, which is used to implement the method for implementing the maintenance-free and evenly loaded planetary roller screw, including a nut, a screw, a roller, an inner gear ring, a planetary carrier and an elastic retaining ring. The pitch value of the nut and the roller is determined by setting the pitch of the roller and the nut as the design parameter to be determined, the screw pitch as a known given parameter, and assuming that the roller-screw and nut-roller contact side threads are ideally distributed with equal loads, and establishing an equal load distribution force matrix F; according to the deformation coordination relationship between the two adjacent threads on the roller-screw and nut-roller contact sides, a deformation coordination equation is established, and in combination with the roller-screw and nut-roller contact side loads and the external load balance equation, a planetary roller screw thread tooth load distribution calculation model is established; based on the planetary roller screw thread tooth load distribution calculation model and the equal load distribution force matrix, the roller and nut gradient pitch is obtained. P Ri and P Ni , calculate the average value of the gradient pitch to get the design pitch of the roller and nut PD R and PD N ; Design the pitch of the roller and nut PD R and PD N The process for designing and manufacturing rollers and nuts for load-balanced planetary roller screws is obtained.

[0030] The beneficial effects of the present invention include:

[0031] The maintenance-free uniformly loaded planetary roller screw and implementation method provided by the present invention include setting the pitch of the roller and the nut as the design parameter to be determined and the pitch of the screw as a known given parameter, thereby establishing an equal load distribution force matrix F; establishing a deformation coordination equation based on the deformation coordination relationship between two adjacent threads on the contact side of the roller-screw and the nut-roller, and establishing a planetary roller screw thread tooth load distribution calculation model in combination with the roller-screw and nut-roller contact side load and external load balance equation; based on the planetary roller screw thread tooth load distribution calculation model and the equal load distribution force matrix, the roller and nut gradient pitches are calculated, and then the gradient pitches are averaged to obtain the roller and nut design pitches. PD R and PD N , the roller and nut are designed to have a pitch of PD R and PD N Design, manufacture and manufacture rollers and nuts for evenly loaded planetary roller screws, to achieve maintenance-free evenly loaded planetary roller screws.

[0032] First of all, the above process achieves a more uniform load distribution on the roller-screw side and the nut-roller side. The constant pitch design and processing of the rollers and nuts eliminates the need for complex thread shaping processing, which greatly improves the load performance of the planetary roller screw while reducing processing and manufacturing costs.

[0033] Secondly, the maintenance-free evenly loaded planetary roller screw of the present invention is composed of a nut, a screw, a roller, an inner gear ring, a planetary carrier, and an elastic retaining ring, wherein the pitch values ​​of the nut and the roller are obtained by the proposed evenly loaded design method. The evenly loaded design method of the planetary roller screw is simple and effective, and relies on few design variables. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The present invention is a flowchart of a method for implementing a maintenance-free and uniformly loaded planetary roller screw.

[0035] Figure 2 The figure is a schematic diagram of the forces and thread numbering of the maintenance-free and uniformly loaded planetary roller screw of the present invention.

[0036] Figure 3 It is a structural schematic diagram of the maintenance-free and uniformly loaded planetary roller screw of the present invention.

[0037] Figure 4 Schematic diagram of the load distribution verification of the planetary roller screw of Example 1 of the present invention and its comparison with the traditional planetary roller screw.

[0038] Figure 5 Schematic diagram of the load distribution verification of the planetary roller screw of Example 2 of the present invention and its comparison with the traditional planetary roller screw.

[0039] Description of the drawings: 1 is a nut; 2 is a lead screw; 3 is a roller; 4 is an inner gear ring; 5 is a planet carrier; 6 is a circlip. DETAILED DESCRIPTION

[0040] The following is combined with Figure 1~Figure 5 The present invention is further described in detail:

[0041] Example 1

[0042] See attached Figure 1 As shown, a method for realizing a maintenance-free uniformly loaded planetary roller screw comprises the following steps:

[0043] S1: Set the pitch of the roller and nut as the design parameter to be determined, the pitch of the screw as a known given parameter, and assume that the thread teeth on the contact side of the roller-screw and nut-roller are ideally equally loaded, thereby establishing an equally loaded force matrix F.

[0044] S2: Based on the deformation coordination relationship between two adjacent threads on the roller-screw and nut-roller contact sides, a deformation coordination equation is established, and combined with the roller-screw and nut-roller contact side load and external load balance equation, a planetary roller screw thread load distribution calculation model is established;

[0045] S3: Based on the planetary roller screw thread load distribution calculation model and the equal load distribution force matrix solution, the roller and nut gradient pitch is obtained P Ri and P Ni , calculate the average value of the gradient pitch to get the design pitch of the roller and nut PD R and PD N ;

[0046] S4: Design the pitch of the roller and nut PD R and PD N Used for the design, processing and manufacture of rollers and nuts for evenly loaded planetary roller screws.

[0047] In this embodiment, the design pitch of the roller and the nut is solved by the proposed planetary roller screw load-balanced design method, and is used for the processing and manufacturing of constant-pitch rollers and nuts. No additional shaping processing of the thread teeth is required, and ultimately uniform load distribution on the roller-screw side and the nut-roller side of the planetary roller screw is achieved, thereby significantly improving the load performance of the planetary roller screw while reducing the processing and manufacturing costs.

[0048] Based on the deformation coordination equation and load balance equation of the roller-screw and nut-roller side of the planetary roller screw, a thread load distribution calculation model is established. Assume that the load distribution is an equal load distribution, and use the equal load distribution force matrix as the input of the thread load distribution calculation model. Solve the load distribution calculation model to obtain the gradient pitch value of the roller and nut, and then calculate the mean value of the gradient pitch of the roller and nut, that is, the design pitch of the roller and nut of the maintenance-free and uniformly loaded planetary roller screw. The rollers and nuts of the planetary roller screw are manufactured according to the constant design pitch, and finally the load performance of the maintenance-free planetary roller screw is greatly improved.

[0049] Example 2

[0050] Based on Example 1, the equal load distribution force matrix F established in step S1 is:

[0051] ;

[0052] in, F RS represents the axial contact load on the roller-screw contact side, F NR is the axial contact load on the nut-roller contact side, and the subscript following it indicates the corresponding thread number. n is the number of roller thread teeth, z is the number of rollers, F 0 is external load.

[0053] In step S2, based on the deformation coordination relationship between two adjacent threads on the contact side of the roller-screw and the nut-roller, the deformation coordination equation expression is established as follows:

[0054] ;

[0055] ;

[0056] in, i The thread number, j is the cumulative lower bound. F RS represents the axial contact load on the roller-screw contact side, F NR is the axial contact load on the nut-roller contact side, and the subscript following it indicates the corresponding thread number.k RSC and k NRC They are the axial contact stiffness of the roller-screw and nut-roller sides, respectively. The subscripts following them indicate the corresponding thread numbers. k RA , k SA and k NA They represent the shaft segment stiffness of the roller, screw and nut respectively, and the subscripts following them represent the corresponding thread number. k RT , k ST and k NT Respectively represent the thread stiffness of the roller, screw and nut, and the subscripts after them represent the corresponding thread numbers. The axial contact stiffness, shaft segment stiffness and thread stiffness are calculated according to the corresponding calculation formulas based on the given design parameters; P R , P S and P N They represent the pitch between adjacent threads of the roller, screw and nut respectively, and the subscripts following them represent the corresponding thread numbers.

[0057] Example 3

[0058] Based on Example 1 or Example 2, Figure 2 The relationship between the roller-screw and nut-roller contact side load and the external load is shown, and the roller-screw and nut-roller contact side load and the external load balance equation expression is established:

[0059] ;

[0060] in, n is the number of roller thread teeth, F is the equal load distribution force matrix, z is the number of rollers, F 0 is external load. Figure 2 The middle arrow indicates the direction of force. At the thread contact point, the forces on the two contact bodies are in opposite directions and equal in magnitude.

[0061] In this embodiment, according to the deformation coordination equation established based on the deformation coordination relationship between two adjacent threads on the contact side of the roller-screw and the nut-roller, and the load and external load balance equation on the contact side of the roller-screw and the nut-roller, a system of equations is formed and converted into a matrix form to establish the planetary roller screw thread load distribution calculation model. The expression of the planetary roller screw thread load distribution calculation model is as follows:

[0062] .

[0063] in, n A is the number of roller thread teeth, 2n×2n represents the matrix composed of stiffness, F 2n×1 represents the uniform load distribution force matrix, z is the number of rollers, F 0 is external load, P R , P S and P N They represent the pitch between adjacent threads of the roller, screw and nut respectively, and the subscripts following them represent the corresponding thread numbers.

[0064] Substitute the known equal load distribution force matrix F into the expression of the planetary roller screw thread load distribution calculation model to solve the gradual pitch value of the roller and nut P Ri and P Ni ,in i ∈[1, n -1], and then find the average value of the gradient pitch solution to obtain the design pitch of the roller and nut PD R and PD N , whose expression is:

[0065] .

[0066] In step S4, the designed pitch is used for the design and manufacturing of the roller and nut. The designed pitch of the roller and nut is a constant value, and there is no need to perform shaping processing on the thread teeth, thereby realizing a planetary roller screw that is free of shaping and meets the requirements of uniform load distribution.

[0067] Through the above steps, the design and processing of the maintenance-free and uniformly loaded planetary roller screw are realized. In order to verify the correctness and effectiveness of the proposed planetary roller screw uniformly loaded design method, the final obtained roller and nut design pitch is PD R and PD NSubstituted back into the planetary roller screw thread load distribution calculation model, and solved by the Newton-Raphson method to obtain the load distribution of the evenly loaded planetary roller screw as shown in Figures 4 and 5, it can be seen that the roller-screw and nut-roller contact sides in the two examples have excellent evenly loaded distribution performance, verifying the correctness and effectiveness of the proposed planetary roller screw evenly loaded design method. In addition, the load distribution of the evenly loaded planetary roller screw of the present invention and the traditional planetary roller screw is compared as shown in Figures 4 and 5, and it can be seen that the load distribution of the maintenance-free evenly loaded planetary roller screw of the present invention is more uniform, so it can greatly improve the load performance of the planetary roller screw.

[0068] A maintenance-free and evenly loaded planetary roller screw is used to implement the method for implementing the maintenance-free and evenly loaded planetary roller screw. As shown in Figure 3, the maintenance-free and evenly loaded planetary roller screw of the present invention consists of a nut 1, a screw 2, a roller 3, an inner gear ring 4, a planet carrier 5 and an elastic retaining ring 6, wherein the pitch value of the nut and the roller is obtained by the proposed load-balancing design method. The pitch value of the nut and the roller is obtained by setting the pitch of the roller and the nut as the design parameter to be determined, the pitch of the screw as a known given parameter, and assuming that the roller-screw and nut-roller contact side threads are ideally equally loaded, and establishing an equal load distribution force matrix F; according to the deformation coordination relationship between two adjacent threads on the roller-screw and nut-roller contact sides, a deformation coordination equation is established, and a planetary roller screw thread load distribution calculation model is established in combination with the roller-screw and nut-roller contact side load and external load balance equation; based on the planetary roller screw thread load distribution calculation model and the equal load distribution force matrix, the roller and nut gradient pitches are calculated, and then the gradient pitches are averaged to obtain the roller and nut design pitches. PD R and PD N ; Design the pitch of the roller and nut PD R and PD N The design and manufacturing process of rollers and nuts for load-balanced planetary roller screws is obtained.

[0069] In summary, the maintenance-free uniformly loaded planetary roller screw and implementation method provided by the present invention set the pitch of the roller and the nut as the design parameter to be determined, the pitch of the screw as a known given parameter, and establish an equal load distribution force matrix F; according to the deformation coordination relationship of two adjacent threads on the contact side of the roller-screw and the nut-roller, a deformation coordination equation is established, and in combination with the contact side load of the roller-screw and the nut-roller and the external load balance equation, a planetary roller screw thread tooth load distribution calculation model is established; based on the planetary roller screw thread tooth load distribution calculation model and the equal load distribution force matrix, the roller and nut gradient pitches are calculated, and then the gradient pitches are averaged to obtain the roller and nut design pitches. PD R and PD N ; Design the pitch of the roller and nut PD R and PD N The design and processing of rollers and nuts for load-equalizing planetary roller screws realizes maintenance-free load-equalizing planetary roller screws. The above process realizes a more uniform load distribution on the roller-screw side and the nut-roller side. The rollers and nuts are designed and manufactured with constant pitch, eliminating the need for complex thread shaping processing, greatly improving the load performance of the planetary roller screw while reducing the processing and manufacturing costs. The maintenance-free load-equalizing planetary roller screw of the present invention is composed of a nut, a screw, a roller, an inner gear ring, a planet carrier, and an elastic retaining ring, wherein the pitch value of the nut and the roller is obtained by the proposed load-equalizing design method. The load-equalizing design method of the planetary roller screw is simple and effective, and relies on few design variables.

Claims

1. A method for realizing a maintenance-free and uniformly loaded planetary roller screw, characterized in that: The following steps are involved: S1: Set the pitch of the roller and nut as the design parameter to be determined, the pitch of the screw as a known given parameter, and assume that the roller-screw and nut-roller contact side threads are ideally distributed with equal loads, thus establishing the equal load distribution force matrix F 2n×1 ; S2: Based on the deformation coordination relationship between two adjacent threads on the roller-screw and nut-roller contact sides, a deformation coordination equation is established. Combining the loads on the roller-screw and nut-roller contact sides with the external load balance equation, a planetary roller screw thread load distribution calculation model is established. S3: Based on the planetary roller screw thread load distribution calculation model and the equal load distribution force matrix, the first load distribution of the roller and the nut is calculated. i Gradual pitch value of pitch thread P Ri and P Ni , calculate the average value of the gradient pitch to get the design pitch of the roller and nut PD R and PD N ; S4: Design the pitch of the roller and nut PD R and PD N Used for the design, processing and manufacture of rollers and nuts for evenly loaded planetary roller screws.

2. A method for realizing a maintenance-free and uniformly loaded planetary roller screw according to claim 1, characterized in that: The equal load distribution force matrix F established in step S1 2n×1 : ； in, F RS represents the axial contact load on the roller-screw contact side, F NR is the axial contact load on the nut-roller contact side, and the subscript following it indicates the corresponding thread number; n is the number of roller thread teeth, z is the number of rollers, F 0 is external load.

3. The method for realizing a maintenance-free and uniformly loaded planetary roller screw according to claim 1, characterized in that: In step S2, based on the deformation coordination relationship between two adjacent threads on the contact side of the roller-screw and the nut-roller, the deformation coordination equation expression is established as follows: ； ； in, i The thread number, j is the cumulative lower bound; F RS represents the axial contact load on the roller-screw contact side, F NR is the axial contact load on the nut-roller contact side, and the subscript following it indicates the corresponding thread number; k RSC and k NRC are the axial contact stiffness of the roller-screw and nut-roller sides, respectively, and the subscripts behind them indicate the corresponding thread number; k RA , k SA and k NA Respectively represent the shaft segment stiffness of the roller, screw and nut, followed by the subscript indicating the corresponding thread number; k RT , k ST and k NT They represent the thread stiffness of the roller, screw and nut respectively, and the subscripts after them represent the corresponding thread numbers; the axial contact stiffness, shaft segment stiffness and thread stiffness are calculated according to the corresponding calculation formulas based on the given design parameters; P Ri , P Si and P Ni Represents the roller, screw and nut i The gradual pitch value of the thread tooth, followed by the subscript indicating the corresponding thread tooth number.

4. A method for realizing a maintenance-free and uniformly loaded planetary roller screw according to claim 3, characterized in that: The roller-screw and nut-roller contact side load and external load balance equation are: ； in, n is the number of roller thread teeth, n is a positive integer, F 2n×1 is the uniform load distribution force matrix, z is the number of rollers, F 0 is external load.

5. A method for realizing a maintenance-free and uniformly loaded planetary roller screw according to claim 4, characterized in that: According to the deformation coordination equation established by the deformation coordination relationship of two adjacent threads on the contact side of the roller-screw and the nut-roller, and the load and external load balance equation on the contact side of the roller-screw and the nut-roller, a set of equations is formed and converted into a matrix form to establish the planetary roller screw thread load distribution calculation model. The expression of the planetary roller screw thread load distribution calculation model is as follows: ； in, n is the number of roller thread teeth, A 2n×2n represents the matrix composed of stiffness, F 2n×1 represents the uniform load distribution force matrix, z is the number of rollers, F 0 is external load, P Ri , P Si and P Ni Represents the roller, screw and nut i The gradual pitch value of the thread tooth, followed by the subscript indicating the corresponding thread tooth number.

6. A method for realizing a maintenance-free and uniformly loaded planetary roller screw according to claim 5, characterized in that: The known uniform load distribution force matrix F 2n×1 Substitute into the expression of the planetary roller screw thread load distribution calculation model, and solve to obtain the first i Gradual pitch value of pitch thread P Ri and P Ni ,in i ∈[1, n -1], and then find the average value of the gradient pitch solution to obtain the design pitch of the roller and nut PD R and PD N , whose expression is: 。 7. A method for realizing a maintenance-free and uniformly loaded planetary roller screw according to claim 6, characterized in that: The design pitch of the roller and nut is used in the design and processing of the roller and nut. Since the design pitch of the roller and nut is a constant value, there is no need to perform profiling on the thread teeth, so a planetary roller screw that does not require profiling and meets the requirements of uniform load distribution can be realized.

8. A maintenance-free and uniformly loaded planetary roller screw, used to implement the method for implementing a maintenance-free and uniformly loaded planetary roller screw as claimed in any one of claims 1 to 7, characterized in that: It includes a nut, a screw, a roller, an inner gear ring, a planet carrier and an elastic retaining ring. The pitch value of the nut and the roller is set by setting the pitch of the roller and the nut as the design parameter to be determined, the pitch of the screw is a known given parameter, and assuming that the thread teeth of the roller-screw and nut-roller contact side are ideally distributed with equal loads, thereby establishing an equal load distribution force matrix F 2n×1 ; According to the deformation coordination relationship of two adjacent threads on the contact side of roller-screw and nut-roller, the deformation coordination equation is established, and the load distribution calculation model of planetary roller screw thread teeth is established by combining the load balance equation of roller-screw and nut-roller contact side; Based on the planetary roller screw thread tooth load distribution calculation model and the equal load distribution force matrix, the first load distribution of roller and nut is obtained. i Gradual pitch value of pitch thread P Ri and P Ni , calculate the average value of the gradient pitch to get the design pitch of the roller and nut PD R and PD N ; Design the pitch of the roller and nut PD R and PD N The process for designing and manufacturing rollers and nuts for load-balanced planetary roller screws is obtained.

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