Roller bearing, speed reducer and robot

Abstract

The invention discloses a roller bearing, a speed reducer and a robot, the speed reducer comprises a cycloidal gear and a crankshaft, the cycloidal gear is provided with a through hole, the crankshaft is sleeved with the cycloidal gear through the through hole, the roller bearing comprises a roller, the roller is arranged between the cycloidal gear and the crankshaft, the roller comprises an end face and a circumferential face, and the end face and the circumferential face are arranged on the cycloidal gear. The circumferential surface is in contact with the hole wall of the through hole and the outer circumferential surface of the crankshaft, the contour line of the circumferential surface comprises an arc section, modification sections and transition sections, the two ends of the arc section are connected with the modification sections respectively, and the two transition sections are connected with the end face and the modification sections respectively. An inner ferrule and an outer ferrule of the roller bearing are omitted, so that the structure of the roller bearing can be simplified; and the contour line of the roller is redesigned, so that the contour line of the circumferential surface of the roller comprises the arc section, the modification section and the transition section, the size of the roller structure is increased, and meanwhile, the load of the roller bearing is dispersed, so that the bearing capacity of the roller bearing is improved.

Description

[0001] This application is a divisional application with the application date of "2023.10.11", application number "202311318399.3", and application name "Method for determining roller contour line of roller bearing, bearing, reducer and robot". Technical Field

[0002] The present invention relates to the technical field of reducers, and in particular to a roller bearing, a reducer and an industrial robot. Background Art

[0003] As an important load-bearing component in RV reducers, roller bearings generally require inner and outer rings to fix the rollers of roller bearings. At present, roller bearings are gradually developing towards the trend of removing the rings. Under such circumstances, large stress concentration will occur at both ends of the rollers of the roller bearings, and the processing, manufacturing and assembly errors of RV reducers will cause axial displacement and tilt of the rollers, further aggravating the stress concentration effect. Summary of the invention

[0004] The embodiments of the present invention provide a roller bearing, a reducer and an industrial robot to solve at least one of the above-mentioned technical problems.

[0005] A roller bearing according to an embodiment of the present invention is used in a reducer, wherein the reducer includes a cycloid gear and a crankshaft, wherein the cycloid gear has a through hole, and the cycloid gear is sleeved on the crankshaft through the through hole, and the roller bearing includes a roller, wherein the roller is arranged between the cycloid gear and the crankshaft, and wherein the roller includes an end face and a circumferential surface, wherein the circumferential surface is in contact with a hole wall of the through hole and an outer circumferential surface of the crankshaft, and wherein a contour line of the circumferential surface includes an arc segment, a shaping segment and a transition segment, wherein both ends of the arc segment are respectively connected to a section of the shaping segment, and two transition segments are respectively connected to the end face and the shaping segment.

[0006] A roller bearing according to an embodiment of the present invention has at least the following beneficial effects: the structure of the roller bearing can be simplified by eliminating the inner and outer rings of the roller bearing; and the contour line of the roller is redesigned so that the contour line of the circumferential surface of the roller includes an arc segment, a shaping segment and a transition segment, the two ends of the arc segment are respectively connected to a shaping segment, and the two transition segments are respectively connected to the end face and the shaping segment, thereby increasing the size of the roller structure and dispersing the load of the roller bearing, thereby improving the load-bearing capacity of the roller bearing.

[0007] According to some embodiments of the present invention, the arc segment is determined by a first contour curve, and the first contour curve is related to the radius of the arc segment and the center diameter of the roller.

[0008] According to some embodiments of the present invention, the first contour curve satisfies the following equation:

[0009]

[0010] Wherein, R1 is the radius of the arc segment, and the value range of R1 is [5Dr1, 50Dr1], and Dr1 is the center diameter of the roller.

[0011] According to some embodiments of the present invention, the shaping segment is determined by a second contour curve, and the second contour curve is related to the radius of the arc segment, the center diameter of the roller, and the end face diameter of the roller.

[0012] According to some embodiments of the present invention, the second contour curve satisfies the following equation:

[0013]

[0014] Among them, R1 is the radius of the arc segment, Dr1 is the center diameter of the roller, Dr2 is the diameter of the end face of the roller, a is the parameter of the curve formula of the modified segment, and the value range of a is [500, 2500]; X1 is the distance between the symmetry axis of the roller perpendicular to the circumference to the connection point of the arc segment and the modified segment, and the value range of X1 is [0.09Lr, 0.35Lr], and Lr is the length of the roller along the axial direction.

[0015] According to some embodiments of the present invention, the transition section is determined by a third contour curve, and the third contour curve is related to an end face diameter of the roller and a center diameter of the roller.

[0016] According to some embodiments of the present invention, the third contour curve satisfies the following equation:

[0017]

[0018] Among them, n and m are parameters of the curve formula of the transition section, and m≥1.15, n≤7.4; Lr is the length of the roller along the axial direction, Dr2 is the diameter of the end face of the roller, and the value range of Dr2 is [0.8Dr1, 0.95Dr1], and Dr1 is the center diameter of the roller.

[0019] According to some embodiments of the present invention, the roller bearing includes a retaining frame, which is arranged on the end surface of the roller and is used to fix the roller in the axial direction of the roller.

[0020] According to some embodiments of the present invention, when the length of the first contact surface between the inner wall surface of the through hole and the roller in the axial direction of the roller is less than or equal to the length of the second contact surface between the outer circumference of the crank shaft and the roller in the axial direction of the roller, the length of the roller along the axial direction ranges from [0.65Lc, 1.25Lc], wherein Lc is the length of the first contact surface between the inner wall surface of the through hole and the roller in the axial direction of the roller.

[0021] According to some embodiments of the present invention, when the length of the first contact surface between the inner wall surface of the through hole and the roller in the axial direction of the roller is greater than the length of the second contact surface between the outer circumference of the crank shaft and the roller in the axial direction of the roller, the length of the roller along the axial direction ranges from [0.75Lc, 1.2Lc], wherein Lc is the length of the first contact surface between the inner wall surface of the through hole and the roller in the axial direction of the roller.

[0022] A reducer according to an embodiment of the present invention includes the roller bearing described in any one of the above embodiments.

[0023] An industrial robot according to an embodiment of the present invention includes the reducer described in the above embodiment.

[0024] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0026] Figure 1 is a flow chart of a method for determining a roller profile of a roller bearing according to an embodiment of the present invention;

[0027] Figure 2 It is a partial structural schematic diagram of a reducer according to an embodiment of the present invention;

[0028] Figure 3 yes Figure 2 The enlarged schematic diagram of part III;

[0029] Figure 4 is another partial structural schematic diagram of a reducer according to an embodiment of the present invention;

[0030] Figures 5 to 7 is a flow chart of a method for determining a roller profile of a roller bearing according to an embodiment of the present invention;

[0031] Figure 8 is a schematic structural diagram of a roller according to an embodiment of the present invention;

[0032] Fig. 9 is a schematic diagram of a profile curve of a roller according to an embodiment of the present invention;

[0033] Fig.10 and Fig.11 is a flow chart of a method for determining a roller profile of a roller bearing according to an embodiment of the present invention;

[0034] Fig.12 is a graph showing the results of simulated contact pressure of the roller according to the embodiment of the present invention.

[0035] Figure Number:

[0036] Roller bearing 10; roller 12; cage 13; cycloid gear 14; crankshaft 16; through hole 18; first contact surface 20, second contact surface 22; end surface 24; circumferential surface 26; arc segment 28; trimming segment 30; transition segment 32;

[0037] Reducer 100. DETAILED DESCRIPTION

[0038] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0039] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0040] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" 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 directly connected or indirectly connected 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.

[0041] 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.

[0042] The disclosure herein provides many different embodiments or examples for realizing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described herein. Of course, they are merely examples, and the purpose is not to limit the present invention. In addition, the present invention may repeat reference numerals and / or reference letters in different examples, and such repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides various specific examples of processes and materials, but those of ordinary skill in the art may appreciate the application of other processes and / or the use of other materials.

[0043] See also Figures 1 to 4 The embodiment of the present invention provides a method for determining the contour line of a roller 12 of a roller bearing 10. The roller bearing 10 is used for a reducer 100. The reducer 100 includes a cycloid gear 14 and a crank shaft 16. The cycloid gear 14 has a through hole 18. The cycloid gear 14 is sleeved on the crank shaft 16 through the through hole 18. The roller bearing 10 includes a roller 12. The roller 12 is arranged between the cycloid gear 14 and the crank shaft 16. The method for determining the contour line of the roller 12 of the roller bearing 10 includes:

[0044] Step S101: Determine the length of the roller 12 along the axial direction according to the length of the first contact surface 20 where the inner wall surface of the through hole 18 contacts the roller 12 along the axial direction of the roller 12 and the length of the second contact surface 22 where the outer peripheral surface of the crankshaft 16 contacts the roller 12 along the axial direction of the roller 12;

[0045] Step S103: determining the center diameter of the roller 12 according to the diameter of the through hole 18, the diameter of the crank shaft 16 and the center diameter of the roller 12;

[0046] Step S105 : determining the contour line of the roller bearing 10 according to the preset contour curve, the length of the roller 12 along the axial direction and the center diameter of the roller 12 .

[0047] The method for determining the contour line of the roller 12 of the above-mentioned roller bearing 10 directly establishes the dimensional relationship between the roller 12 and the crank shaft 16 and the cycloid gear 14, eliminates the inner and outer rings of the roller bearing 10, and redesigns the contour line of the roller 12. This can simplify the structure of the roller bearing 10, thereby increasing the size of the roller 12 structure, and at the same time can disperse the load of the roller bearing 10 and have a stronger load-bearing capacity.

[0048] Specifically, the roller bearing 10 can be applied to the reducer 100. Optionally, the reducer 100 can be an RV (Rotary Vector) reducer 100. The RV reducer 100 is a core component of an industrial robot and has the advantages of high precision, high rigidity and long life. The RV reducer 100 is composed of a planetary gear transmission assembly and a cycloid gear 14 transmission assembly.

[0049] The motion transmission path of the RV reducer 100 starts from the input shaft, and the motion and force are transmitted to the planetary gears through the meshing of the input shaft and the planetary gears. The planetary gears are connected to the crankshaft 16, and the crankshaft 16 and the planetary gears make the same motion. The cycloid gear 14 has a through hole 18, and the cycloid gear 14 is sleeved on the flange of the crankshaft 16 through the through hole 18. The crankshaft 16 will drive the cycloid gear 14 to make an eccentric motion and mesh with the pin teeth, and finally transmit the load and motion to the output shaft.

[0050] Heavy load and high power density are two important functional performance indicators of RV reducer 100. High power density requires the reducer to have a smaller volume and mass, and higher gear performance indicators under the same output power and torque. Gear performance indicators mainly include: reducer accuracy and accuracy retention, stiffness and strength performance, vibration and noise characteristics, etc.

[0051] High power density and heavy loads lead to further reduction in the spatial dimensions of the RV reducer 100, while the loads of each component are greater. As an important load-bearing component in the RV reducer 100, the roller bearing 10 is gradually developing towards the trend of de-ringing. In this case, large stress concentration will occur at both ends of the roller 12 of the roller bearing 10, and the processing, manufacturing and assembly errors of the RV reducer 100 will cause axial displacement and tilt of the roller 12, further aggravating the stress concentration effect, thereby affecting the service life of the reducer 100.

[0052] A method for determining the contour line of a roller 12 of a roller bearing 10 provided in an embodiment of the present invention directly establishes a dimensional relationship between the roller 12 and the crank shaft 16 and the cycloid gear 14 by removing the inner and outer rings of the roller bearing 10, thereby simplifying the structure of the roller bearing 10 and increasing the size of the roller 12 structure.

[0053] like Figure 2 and Figure 3 As shown, the roller bearing 10 includes a roller 12 and a cage 13. The roller bearing 10 is arranged in a through hole 18, wherein the circumferential surface 26 of the roller 12 contacts the inner wall surface of the through hole 18 and the outer circumferential surface of the crank shaft 16, and the cage 13 is fixed to the end surfaces 24 on both sides of the roller 12, and the roller 12 is restricted in the axial direction of the roller 12 to prevent the roller 12 from escaping from the through hole 18.

[0054] like Figures 2 to 4 As shown in the figure, the length of the first contact surface 20 where the inner wall surface of the through hole 18 contacts the roller 12 along the axial direction of the roller 12 is recorded as Lc, the length of the second contact surface 22 where the outer peripheral surface of the crankshaft 16 contacts the roller 12 along the axial direction of the roller 12 is recorded as Ls, and the length of the roller 12 along the axial direction is recorded as Lr. The diameter of the through hole 18 is recorded as Dc, the diameter of the crankshaft 16 is recorded as Ds, and the center diameter of the roller 12 is recorded as Dr1.

[0055] When designing the contour line of the roller 12, the length Lr of the roller 12 along the axial direction is determined based on the length Lc of the first contact surface 20 where the inner wall surface of the through hole 18 contacts the roller 12 along the axial direction of the roller 12 and the length Ls of the second contact surface 22 where the outer peripheral surface of the crank shaft 16 contacts the roller 12 along the axial direction of the roller 12.

[0056] The center diameter Dr1 of the roller 12 is determined according to the diameter Dc of the through hole 18, the diameter Ds of the crankshaft 16 and the center diameter Dr1 of the roller 12. Specifically, the center diameter Dr1 of the roller 12, the diameter Dc of the through hole 18 and the diameter Ds of the crankshaft 16 satisfy the following relationship: 0.975≤2Dr1 / (Dc-Ds)≤0.991.

[0057] The contour line of the roller bearing 10 is determined based on the length Lr of the roller 12 along the axial direction, the center diameter Dr1 of the roller 12, and a preset contour curve.

[0058] The standard roller 12 is modified according to the contour of the roller bearing 10 . When the roller bearing 10 obtained is applied to the reducer 100 , the load of the roller 12 is dispersed and the roller 12 has a stronger load-bearing capacity.

[0059] See also Figure 5In some embodiments, step S101 includes:

[0060] Step S1011: When the length of the first contact surface 20 where the inner wall surface of the through hole 18 contacts the roller 12 along the axial direction of the roller 12 is less than or equal to the length of the second contact surface 22 where the outer peripheral surface of the crankshaft 16 contacts the roller 12 along the axial direction of the roller 12, the length of the roller 12 along the axial direction ranges from [0.65Lc, 1.25Lc], where Lc is the length of the first contact surface 20 where the inner wall surface of the through hole 18 contacts the roller 12 along the axial direction of the roller 12.

[0061] In this way, the length Lr of the roller 12 along the axial direction can be determined based on the dimensional relationship between Lc and Ls.

[0062] Specifically, the length Lr of the roller 12 along the axial direction is determined based on the length Lc of the first contact surface 20 where the inner wall surface of the through hole 18 contacts the roller 12 along the axial direction of the roller 12, the length Ls of the second contact surface 22 where the outer peripheral surface of the crankshaft 16 contacts the roller 12 along the axial direction of the roller 12, and the range of values ​​of Lr / Lc. When Lc≤Ls, 0.65Lc≤Lr≤1.25Lc, and the value of the length Lr of the roller 12 along the axial direction can be determined based on the determined value of Lc. For example, the value of Lr can be 0.65Lc, 0.7Lc, 0.78Lc, 0.8Lc, 0.84Lc, 0.9Lc, 0.95Lc, 1Lc, 1.15Lc or 1.25Lc, or any value within the range [0.65Lc, 1.25Lc].

[0063] See also Figure 6 In some embodiments, step S101 includes:

[0064] Step S1013: When the length of the first contact surface 20 where the inner wall surface of the through hole 18 contacts the roller 12 along the axial direction of the roller 12 is greater than the length of the second contact surface 22 where the outer peripheral surface of the crank shaft 16 contacts the roller 12 along the axial direction of the roller 12, the length of the roller 12 along the axial direction ranges from [0.75Lc, 1.2Lc], wherein Lc is the length of the first contact surface 20 where the inner wall surface of the through hole 18 contacts the roller 12 along the axial direction of the roller 12.

[0065] In this way, the length Lr of the roller 12 along the axial direction can be determined based on the dimensional relationship between Lc and Ls.

[0066] Specifically, the length Lr of the roller 12 along the axial direction is determined based on the length Lc of the first contact surface 20 where the inner wall surface of the through hole 18 contacts the roller 12 along the axial direction of the roller 12, the length Ls of the second contact surface 22 where the outer peripheral surface of the crankshaft 16 contacts the roller 12 along the axial direction of the roller 12, and the value range of Lr / Lc. When Lc is greater than Ls, 0.75Lc≤Lr≤1.2Lc, and the value of the length Lr of the roller 12 along the axial direction can be determined based on the determined value of Lc. For example, the value of Lr can be 0.75Lc, 0.78Lc, 0.8Lc, 0.84Lc, 0.9Lc, 0.95Lc, 1Lc, 1.05Lc, 1.15Lc or 1.2Lc, or any value within the range [0.75Lc, 1.2Lc].

[0067] See also Figure 7 In some embodiments, the roller 12 includes an end face 24 and a circumferential surface 26, the circumferential surface 26 contacts the hole wall of the through hole 18 and the outer circumferential surface of the crank shaft 16, the contour line of the circumferential surface 26 includes an arc segment 28, a trimming segment 30 and a transition segment 32, the two ends of the arc segment 28 are respectively connected to a trimming segment 30, and the two transition segments 32 are respectively connected to the end face 24 and the trimming segment 30, the preset contour curve includes a first contour curve, and step S105 includes:

[0068] Step S1051 : Determine the contour line of the arc segment 28 according to the first contour curve, the length of the roller 12 along the axial direction and the center diameter of the roller 12 , wherein the first contour curve is related to the radius of the arc segment 28 and the center diameter of the roller 12 .

[0069] In this way, the contour line of the arc segment 28 of the circumferential surface 26 of the roller 12 can be determined according to the first contour curve.

[0070] Specifically, if Figure 8 and Fig. 9 As shown, the roller 12 includes an end face 24 and a circumferential surface 26, wherein the circumferential surface 26 contacts the hole wall of the through hole 18 and the outer circumference of the crankshaft 16. The circumferential surface 26 is divided into an arc segment 28, a modified segment 30 and a transition segment 32.

[0071] To illustrate the positional relationship, Figure 8 and Fig. 9 In the figure, lines with different line widths are used to represent the end face 24 and the circumferential face 26 respectively, and lines with different grayscales are used to represent the arc segment 28, the shaping segment 30 and the transition segment 32 respectively.

[0072] The arc segment 28 and the modified segment 30 are the main load-bearing areas. The modified segment 30 can further increase the curvature of the contour line of the roller 12 to ensure that the main load-bearing area is within the arc segment 28 and the modified segment 30. The transition segment 32 can ensure that the contour line is smoothly connected to the two ends of the roller 12 to reduce the stress concentration at the two ends of the roller 12. Based on the above design concept, the contour curves of the arc segment 28, the modified segment 30 and the transition segment 32 are designed.

[0073] The first contour curve is Wherein, R1 is the radius of the arc segment 28, and the value range of R1 is [5Dr1, 50Dr1]. According to the size relationship between Lc and Ls, the length Lr of the roller 12 along the axial direction is determined, and according to the diameter Dc of the through hole 18, the diameter Ds of the crankshaft 16 and the center diameter Dr1 of the roller 12, the center diameter Dr1 of the roller 12 is determined.

[0074] See also Fig.10 In some embodiments, the preset contour curve further includes a second contour curve, and step S105 includes:

[0075] Step S1053: Determine the contour line of the shaping segment 30 according to the second contour curve, the length of the roller 12 along the axial direction and the center diameter of the roller 12. The second contour curve is related to the radius of the arc segment 28, the center diameter of the roller 12 and the diameter of the end face 24 of the roller 12.

[0076] In this way, the contour line of the modified section 30 of the circumferential surface 26 of the roller 12 can be determined according to the second contour curve.

[0077] Specifically, the second contour curve is Among them, R1 is the radius of the arc segment 28, Dr1 is the center diameter of the roller 12, Dr2 is the diameter of the end face 24 of the roller 12, a is the parameter of the curve formula of the shaping segment 30, and the value range of a is [500, 2500], X1 is the distance between the symmetry axis of the roller 12 perpendicular to the circumference and the connection point between the arc segment 28 and the shaping segment 30, and the value range of X1 is [0.09Lr, 0.35Lr], and X2 is the distance between the symmetry axis of the roller 12 perpendicular to the circumference and the connection point between the shaping segment 30 and the transition segment 32, and the value range of X2 is [0.12Lr, 0.47Lr].

[0078] For example, the value of X1 can be 0.09Lr, 0.1Lr, 0.15Lr, 0.17Lr, 0.2Lr, 0.25Lr, 0.28Lr, 0.3Lr, 0.32Lr or 0.35Lr, or any value in the range [0.09Lr, 0.35Lr], and the value of X2 can be 0.12Lr, 0.15Lr, 0.2Lr, 0.23Lr, 0.28Lr, 0.34Lr, 0.38Lr, 0.4Lr, 0.45Lr or 0.47Lr, or any value in the range [0.12Lr, 0.47Lr].

[0079] See also Fig.11 In some embodiments, the preset contour curve further includes a third contour curve, and step S105 includes:

[0080] Step S1055: Determine the contour line of the transition section 32 according to the third contour curve, the length of the roller 12 along the axial direction and the center diameter of the roller 12 , wherein the third contour curve is related to the diameter of the end face 24 of the roller 12 and the center diameter of the roller 12 .

[0081] In this way, the contour line of the transition section 32 of the circumferential surface 26 of the roller 12 can be determined according to the third contour curve.

[0082] Specifically, the third contour curve is Among them, n and m are parameters of the curve formula of the transition section 32, m≥1.15, n≤7.4, Dr2 is the diameter of the end face 24 of the roller 12, and the value range of Dr2 is [0.8Dr1, 0.95Dr1]. For example, the value of Dr2 can be 0.8Dr1, 0.82Dr1, 0.85Dr1, 0.86Dr1, 0.88Dr1, 0.89Dr1, 0.9Dr1, 0.92Dr1, 0.94Dr1 or 0.95Dr1, or any value in the range [0.8Dr1, 0.95Dr1].

[0083] In summary, the method for determining the contour line of the roller 12 of the roller bearing 10 provided in the embodiment of the present invention establishes the dimensional relationship between the roller 12 and the crank shaft 16 and the cycloid gear 14 , and obtains the macroscopic limitation of the size of the roller 12 .

[0084] On this basis, a contour curve is set for the contour line of the circumference of the roller 12, and the size of the roller 12 is further microscopically limited. Thus, the contour line of the roller 12 is obtained, and the standard roller 12 is modified accordingly. The modified roller 12 can ensure that the central area of ​​the circumferential surface 26 of the roller 12 is used as the main load-bearing area, reduce the stress concentration at both ends of the roller 12, and thus make the roller 12 have a stronger load-bearing capacity.

[0085] According to the above method for determining the contour line of the roller 12 of the roller bearing 10, the standard roller 12 is subjected to the profile modification process to obtain the roller bearing 10. The load distribution on the circumferential surface 26 thereof is as follows: Fig.12 As shown, the curves of different grayscales from top to bottom represent the loads of the circumferential surface 26 of the roller 12 without modification and with different modification amounts, respectively. Fig.12 In FIG. 1 , the ordinate is the contact pressure of the circumferential surface 26 , and the abscissa is the value of X in the preset profile curve.

[0086] A roller bearing 10 according to an embodiment of the present invention is used in a reducer 100. The roller 12 of the roller bearing 10 is processed from a standard roller 12 by using the method for determining the contour line of the roller 12 of the roller bearing 10 according to any one of the above embodiments.

[0087] In some embodiments, the roller bearing 10 includes a roller 12 and a retainer 13, the roller 12 includes an end face 24 and a circumferential surface 26, the circumferential surface 26 is in contact with the hole wall of the through hole 18 and the outer circumferential surface of the crank shaft 16, and the retainer 13 is arranged on the end face 24 of the roller 12 for fixing the roller 12 in the axial direction of the roller 12.

[0088] In this way, the size of each contour line on the circumferential surface 26 can be limited respectively, so as to control the load distribution on the circumferential surface 26 .

[0089] Specifically, if Figure 8 and Fig. 9 As shown, the roller 12 includes an end face 24 and a circumferential surface 26, wherein the circumferential surface 26 contacts the hole wall of the through hole 18 and the outer circumference of the crankshaft 16. The circumferential surface 26 is divided into an arc segment 28, a modified segment 30 and a transition segment 32.

[0090] The arc segment 28 and the modified segment 30 are the main load-bearing areas. The modified segment 30 can further increase the curvature of the contour line of the roller 12 to ensure that the main load-bearing area is within the arc segment 28 and the modified segment 30. The transition segment 32 can ensure that the contour line is smoothly connected to the two ends of the roller 12 to reduce the stress concentration at the two ends of the roller 12. Based on the above design concept, the contour curves of the arc segment 28, the modified segment 30 and the transition segment 32 are designed.

[0091] In certain embodiments, when the length of the first contact surface 20 where the inner wall surface of the through hole 18 contacts the roller 12 in the axial direction of the roller 12 is less than or equal to the length of the second contact surface 22 where the outer peripheral surface of the crankshaft 16 contacts the roller 12 in the axial direction of the roller 12, the length of the roller 12 along the axial direction ranges from [0.65Lc, 1.25Lc], where Lc is the length of the first contact surface 20 where the roller 12 contacts the roller 12 in the axial direction of the roller 12.

[0092] In this way, the length of the roller 12 along the axial direction can be determined based on the length of the first contact surface 20 where the inner wall surface of the through hole 18 contacts the roller 12 in the axial direction of the roller 12 and the length of the second contact surface 22 where the outer peripheral surface of the crank shaft 16 contacts the roller 12 in the axial direction of the roller 12, thereby making the roller bearing 10 suitable for reducers 100 of different sizes or models.

[0093] The length Lr of the roller 12 along the axial direction is determined based on the length Lc of the first contact surface 20 where the inner wall surface of the through hole 18 contacts the roller 12, the length Ls of the second contact surface 22 where the outer peripheral surface of the crankshaft 16 contacts the roller 12, and the range of Lr / Lc. When Lc≤Ls, 0.65Lc≤Lr≤1.25Lc, and the value of the length Lr of the roller 12 along the axial direction can be determined based on the determined value of Lc. For example, the value of Lr can be 0.65Lc, 0.7Lc, 0.78Lc, 0.8Lc, 0.84Lc, 0.9Lc, 0.95Lc, 1Lc, 1.15Lc, or 1.25Lc, or any value within the range [0.65Lc, 1.25Lc].

[0094] In certain embodiments, when the length of the first contact surface 20 where the inner wall surface of the through hole 18 contacts the roller 12 in the axial direction of the roller 12 is greater than the length Ls of the second contact surface 22 where the outer peripheral surface of the crankshaft 16 contacts the roller 12 in the axial direction of the roller 12, the length of the roller 12 along the axial direction ranges from [0.75Lc, 1.2Lc], where Lc is the length of the first contact surface 20 where the roller 12 contacts the roller 12 in the axial direction of the roller 12.

[0095] In this way, the length of the roller 12 along the axial direction can be determined based on the length of the first contact surface 20 where the inner wall surface of the through hole 18 contacts the roller 12 in the axial direction of the roller 12 and the length of the second contact surface 22 where the outer peripheral surface of the crank shaft 16 contacts the roller 12 in the axial direction of the roller 12, thereby making the roller bearing 10 suitable for reducers 100 of different sizes or models.

[0096] Specifically, the length Lr of the roller 12 along the axial direction is determined based on the length Lc of the first contact surface 20 where the inner wall surface of the through hole 18 contacts the roller 12 along the axial direction of the roller 12, the length Ls of the second contact surface 22 where the outer peripheral surface of the crankshaft 16 contacts the roller 12 along the axial direction of the roller 12, and the value range of Lr / Lc. When Lc is greater than Ls, 0.75Lc≤Lr≤1.2Lc, and the value of the length Lr of the roller 12 along the axial direction can be determined based on the determined value of Lc. For example, the value of Lr can be 0.75Lc, 0.78Lc, 0.8Lc, 0.84Lc, 0.9Lc, 0.95Lc, 1Lc, 1.05Lc, 1.15Lc or 1.2Lc, or any value within the range [0.75Lc, 1.2Lc].

[0097] The diameter Dc of the through hole 18 and the diameter Ds of the crankshaft 16 are related to the center diameter Dr1 of the roller 12. Specifically, the center diameter Dr1 of the roller 12 and the diameter Dc of the through hole 18 and the diameter Ds of the crankshaft 16 satisfy the following relationship: 0.975≤2Dr1 / (Dc-Ds)≤0.991.

[0098] In some embodiments, the contour line of the circumferential surface 26 includes an arc segment 28 , a shaping segment 30 and a transition segment 32 . The two ends of the arc segment 28 are respectively connected to a shaping segment 30 , and two transition segments 32 are respectively connected to the end surface 24 and the shaping segment 30 .

[0099] In this way, each section of the circumferential surface 26 can have different sizes, so that the main load-bearing area can be controlled within the arc section 28 and the modified section 30, thereby reducing the stress concentration at both ends of the roller 12.

[0100] Specifically, the roller 12 includes an end face 24 and a circumferential surface 26, and the circumferential surface 26 contacts the hole wall of the through hole 18 and the outer circumferential surface of the crankshaft 16. The circumferential surface 26 is divided into an arc segment 28, a modified segment 30 and a transition segment 32. The arc segment 28 and the modified segment 30 are the main load-bearing areas. The modified segment 30 can further increase the curvature of the contour line of the roller 12 to ensure that the main load-bearing area is within the arc segment 28 and the modified segment 30; the transition segment 32 can ensure that the contour line is smoothly connected to the two ends of the roller 12, thereby reducing the stress concentration at the two ends of the roller 12.

[0101] In some embodiments, the arc segment 28 is defined by a first profile curve, which is related to the radius of the arc segment 28 and the center diameter of the roller 12 .

[0102] In this way, the contour line of the arc segment 28 is determined according to the first contour curve, and different sizes of roller bearings 10 can have different contour line sizes, so that the roller bearing 10 is suitable for reducers 100 of different sizes or models.

[0103] Specifically, the first contour curve is Wherein, R1 is the radius of the arc segment 28, and the value range of R1 is [5Dr1, 50Dr1]. According to the size relationship between Lc and Ls, the length Lr of the roller 12 along the axial direction is determined, and according to the diameter Dc of the through hole 18, the diameter Ds of the crankshaft 16 and the center diameter Dr1 of the roller 12, the center diameter Dr1 of the roller 12 is determined.

[0104] In some embodiments, the modified segment 30 is determined by a second contour curve, which is related to the radius of the arc segment 28 , the center diameter of the roller 12 , and the diameter of the end face 24 of the roller 12 .

[0105] In this way, the contour line of the modified section 30 is determined according to the second contour curve, and different contour line sizes can be provided for roller bearings 10 of different sizes, so that the roller bearing 10 is suitable for reducers 100 of different sizes or models.

[0106] Specifically, the second contour curve is Among them, R1 is the radius of the arc segment 28, Dr1 is the center diameter of the roller 12, Dr2 is the diameter of the end face 24 of the roller 12, a is the parameter of the curve formula of the shaping segment 30, and the value range of a is [500, 2500], X1 is the distance between the symmetry axis of the roller 12 perpendicular to the circumference and the connection point between the arc segment 28 and the shaping segment 30, and the value range of X1 is [0.09Lr, 0.35Lr], and X2 is the distance between the symmetry axis of the roller 12 perpendicular to the circumference and the connection point between the shaping segment 30 and the transition segment 32, and the value range of X2 is [0.12Lr, 0.47Lr].

[0107] For example, the value of X1 can be 0.09Lr, 0.1Lr, 0.15Lr, 0.17Lr, 0.2Lr, 0.25Lr, 0.28Lr, 0.3Lr, 0.32Lr or 0.35Lr, or any value in the range [0.09Lr, 0.35Lr], and the value of X2 can be 0.12Lr, 0.15Lr, 0.2Lr, 0.23Lr, 0.28Lr, 0.34Lr, 0.38Lr, 0.4Lr, 0.45Lr or 0.47Lr, or any value in the range [0.12Lr, 0.47Lr].

[0108] In certain embodiments, the transition segment 32 is defined by a third profile curve that is related to the diameter of the end face 24 of the roller 12 and the center diameter of the roller 12 .

[0109] In this way, the contour line of the transition section 32 is determined according to the third contour curve, and different contour line sizes can be provided for roller bearings 10 of different sizes, so that the roller bearing 10 is suitable for reducers 100 of different sizes or models.

[0110] Specifically, the third contour curve is Among them, n and m are parameters of the curve formula of the transition section 32, m≥1.15, n≤7.4, Dr2 is the diameter of the end face 24 of the roller 12, and the value range of Dr2 is [0.8Dr1, 0.95Dr1]. For example, the value of Dr2 can be 0.8Dr1, 0.82Dr1, 0.85Dr1, 0.86Dr1, 0.88Dr1, 0.89Dr1, 0.9Dr1, 0.92Dr1, 0.94Dr1 or 0.95Dr1, or any value in the range [0.8Dr1, 0.95Dr1].

[0111] In summary, the roller bearing 10 provided in the embodiment of the present invention has the following advantages:

[0112] (1) The inner and outer rings of the roller bearing 10 are removed, and the roller 12 of the roller bearing 10 is in direct contact with the crank shaft 16 and the cycloid gear 14. Therefore, the size of the roller 12 can be increased. At the same time, the structure of the roller bearing 10 is simpler and the processing difficulty is reduced.

[0113] (2) By coupling the macroscopic dimensions of the roller 12 of the roller bearing 10 with the structural dimensions of the crankshaft 16 and the cycloid wheel, the dimensions of the roller bearing 10 can be designed according to reducers of different models or sizes, thereby making the roller bearing 10 more applicable.

[0114] (3) The contour line of the roller 12 is designed with multiple curved segments, with the arc segment 28 and the modified segment 30 serving as the main load-bearing areas. The modified segment 30 can further increase the curvature of the contour line of the roller 12 to ensure that the main load-bearing area is within the arc segment 28 and the modified segment 30. The transition segment 32 can ensure that the contour line is smoothly connected to both ends of the roller 12, thereby reducing stress concentration at both ends of the roller 12.

[0115] A reducer 100 according to an embodiment of the present invention includes the roller bearing 10 according to any one of the above embodiments.

[0116] An industrial robot according to an embodiment of the present invention includes the reducer 100 according to the above embodiment.

[0117] The above-mentioned roller bearing 10, reducer 100 and industrial robot directly establish the size relationship between the roller 12 and the crank shaft 16 and the cycloid gear 14, eliminate the inner and outer rings of the roller bearing 10, and redesign the contour line of the roller 12, which can simplify the structure of the roller bearing 10, thereby increasing the size of the roller 12 structure, and at the same time can disperse the load of the roller bearing 10, so that it has a stronger load-bearing capacity.

[0118] It should be noted that the above explanation of the implementation method and beneficial effects of the cycloid gear 14 is also applicable to the reducer 100 and the industrial robot used in the implementation method of the present invention, and will not be elaborated here in order to avoid redundancy.

[0119] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0120] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A roller bearing for a reducer, the reducer comprising a cycloid gear and a crankshaft, the cycloid gear having a through hole, the cycloid gear being sleeved on the crankshaft through the through hole, the roller bearing comprising a roller, the roller being arranged between the cycloid gear and the crankshaft, characterized in that: The roller includes an end face and a circumferential surface, the circumferential surface is in contact with the hole wall of the through hole and the outer circumferential surface of the crank shaft, the contour line of the circumferential surface includes an arc segment, a shaping segment and a transition segment, the two ends of the arc segment are respectively connected to a section of the shaping segment, and the two transition segments are respectively connected to the end face and the shaping segment.

2. The roller bearing according to claim 1, characterized in that The arc segment is determined by a first contour curve, which is related to the radius of the arc segment and the center diameter of the roller.

3. The roller bearing according to claim 2, characterized in that: The first contour curve satisfies the following equation: Wherein, R1 is the radius of the arc segment, and the value range of R1 is [5Dr1, 50Dr1], and Dr1 is the center diameter of the roller.

4. The roller bearing according to claim 1, characterized in that The modified segment is determined by a second contour curve, which is related to the radius of the arc segment, the center diameter of the roller, and the end face diameter of the roller.

5. The roller bearing according to claim 4, characterized in that The second contour curve satisfies the following equation: Among them, R1 is the radius of the arc segment, Dr1 is the center diameter of the roller, Dr2 is the diameter of the end face of the roller, a is the parameter of the curve formula of the modified segment, and the value range of a is [500, 2500]; X1 is the distance between the symmetry axis of the roller perpendicular to the circumference to the connection point of the arc segment and the modified segment, and the value range of X1 is [0.09Lr, 0.35Lr], and Lr is the length of the roller along the axial direction.

6. The roller bearing according to claim 1, characterized in that The transition section is determined by a third contour curve, and the third contour curve is related to the end face diameter of the roller and the center diameter of the roller.

7. The roller bearing according to claim 6, characterized in that The third contour curve satisfies the following equation: Among them, n and m are parameters of the curve formula of the transition section, and m≥1.15, n≤7.4; Lr is the length of the roller along the axial direction, Dr2 is the diameter of the end face of the roller, and the value range of Dr2 is [0.8Dr1, 0.95Dr1], and Dr1 is the center diameter of the roller.

8. The roller bearing according to claim 1, characterized in that The roller bearing comprises a retaining frame, which is arranged on the end surface of the roller and is used to fix the roller in the axial direction of the roller.

9. The roller bearing according to claim 1, characterized in that When the length of the first contact surface between the inner wall of the through hole and the roller in the axial direction of the roller is less than or equal to the length of the second contact surface between the outer circumference of the crankshaft and the roller in the axial direction of the roller, the length of the roller along the axial direction ranges from [0.65Lc, 1.25Lc], wherein Lc is the length of the first contact surface between the inner wall of the through hole and the roller in the axial direction of the roller.

10. The roller bearing according to claim 1, characterized in that When the length of the first contact surface between the inner wall surface of the through hole and the roller in the axial direction of the roller is greater than the length of the second contact surface between the outer peripheral surface of the crank shaft and the roller in the axial direction of the roller, the length of the roller along the axial direction ranges from [0.75Lc, 1.2Lc], wherein Lc is the length of the first contact surface between the inner wall surface of the through hole and the roller in the axial direction of the roller.

11. A reducer, characterized in that: The roller bearing comprises the roller bearing described in any one of claims 1 to 10.

12. An industrial robot, characterized in that: Including the reducer as claimed in claim 11.

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