A cycloidal speed reducer

Abstract

The application provides a cycloid speed reducer, comprising an input mechanism, an eccentric mechanism, a first bearing assembly, a cycloid gear mechanism, an output mechanism and a rack; the input mechanism comprises an input shaft and a cylindrical pin; the eccentric mechanism is sleeved on the input shaft through the cylindrical pin, and the cycloid gear mechanism is sleeved on the eccentric mechanism through the first bearing assembly; the rack is provided with a plurality of outer needle rollers arranged in a circumferential array; the output mechanism is provided with a plurality of inner needle rollers arranged in a circumferential array; the outer edge tooth profile of the cycloid gear mechanism is engaged with the outer needle rollers, and the inner needle rollers are correspondingly arranged in the output holes of the cycloid gear mechanism; when the input shaft rotates, the input shaft drives the cycloid gear mechanism to perform eccentric motion through the eccentric mechanism, and the cycloid gear mechanism drives the output mechanism to rotate through the inner needle rollers. The cylindrical pin is used to connect the input shaft and the eccentric mechanism, so that a relatively closed oil leakage prevention structure can be reserved, and the fatigue strength requirement can be met.

Description

Technical Field

[0001] This application relates to the field of mechanical transmission technology, and in particular to a cycloidal pinwheel reducer. Background Technology

[0002] The cycloidal pinwheel reducer is a high-precision planetary transmission device that achieves speed reduction by driving a cycloidal wheel with a fixed pinwheel via an eccentric shaft. Its core component is a cycloidal wheel with short-amplitude epicycloidal teeth, which meshes simultaneously with the pinwheel, providing advantages such as a large reduction ratio, smooth transmission, low backlash, and high load-bearing capacity. The output mechanism converts the eccentric motion of the cycloidal wheel into fixed-axis rotation, transmitting high torque. This reducer features a compact structure, high rigidity, and long service life, and is widely used in precision transmission fields such as industrial robots, CNC machine tools, and automated equipment, making it a key component of modern intelligent manufacturing.

[0003] The input structure of a cycloidal pinwheel reducer needs to transmit torque to an eccentric wheel to drive the cycloidal wheel. Since the input shaft usually rotates at a high speed, it has high fatigue strength requirements. The matching structure between the input shaft and the eccentric wheel has become a major design challenge.

[0004] This section cites Chinese patent document CN104791425A, which discloses an input shaft connected to a corresponding eccentric structure via a key. However, traditional flat key pins often face the problem of stress concentration at the right angle of the key pin groove. For keyed shafts subjected to long-term rotation and cyclic stress, fatigue cracks typically begin to extend from this stress concentration point until the remaining structure can no longer withstand the applied torque, rapidly failing under shear stress and ultimately failing.

[0005] This section cites Chinese patent document CN118998268A, which discloses a method where the input shaft is directly connected to a corresponding eccentric structure, and the torque is directly transmitted to the corresponding eccentric structure via the double D-shaped structure of the input shaft. However, while this method is cheaper, under high-speed operation, the grease inside the reducer is prone to overflowing from the D-shaped opening at the end of the input shaft, causing grease loss from the reducer, resulting in environmental pollution and insufficient internal lubrication.

[0006] It is evident that the input structure of existing cycloidal pinwheel reducers is insufficient to meet the technical requirements for fatigue strength and oil leakage prevention.

[0007] It should be noted that the information in the background section above is only used to enhance the understanding of the background technology of this application, and therefore may include technical information that does not constitute technical information known or easily inferred by a person skilled in the art. Utility Model Content

[0008] In view of the above problems, this application is made in order to provide a cycloidal pinwheel reducer that overcomes or at least partially solves the above problems.

[0009] This application provides a cycloidal pinwheel reducer, comprising: an input mechanism, an eccentric mechanism, a first bearing assembly, a cycloidal wheel mechanism, an output mechanism, and a frame; the input mechanism includes an input shaft and a cylindrical pin. The eccentric mechanism is sleeved on the input shaft via the cylindrical pin, and the cycloidal wheel mechanism is sleeved on the eccentric mechanism via the first bearing assembly; The frame includes a plurality of spaced-out outer roller needles; the output mechanism includes a plurality of spaced-out inner roller needles; the outer edge tooth profile of the cycloidal wheel mechanism meshes with the outer roller needles, and the inner roller needles are correspondingly inserted into the output hole of the cycloidal wheel mechanism; When the input shaft rotates, the input shaft drives the cycloidal wheel mechanism to perform eccentric motion through the eccentric mechanism, and the cycloidal wheel mechanism drives the output mechanism to rotate through the inner needle roller.

[0010] Furthermore, the eccentric mechanism includes a first eccentric bushing and a second eccentric bushing; The first eccentric bushing is provided with a first eccentric wheel; the second eccentric bushing is provided with a second eccentric wheel; the first eccentric bushing and the second eccentric bushing abut against each other along the axial direction, and a third eccentric wheel is formed at the abutment portion; The cycloidal wheel mechanism is sleeved on the first eccentric wheel, the second eccentric wheel, and the third eccentric wheel via the first bearing assembly.

[0011] Furthermore, the first bearing assembly includes: a first eccentric bearing, a second eccentric bearing, and a third eccentric bearing; The first eccentric bearing is sleeved on the first eccentric wheel; the second eccentric bearing is sleeved on the second eccentric wheel; and the third eccentric bearing is sleeved on the third eccentric wheel.

[0012] Furthermore, the cycloidal wheel mechanism includes a first cycloidal wheel, a second cycloidal wheel, and a third cycloidal wheel; The first cycloidal wheel is sleeved on the first eccentric bearing; the second cycloidal wheel is sleeved on the second eccentric bearing; and the third cycloidal wheel is sleeved on the third eccentric bearing.

[0013] Furthermore, the input shaft is provided with a first pin groove; the first eccentric bushing is provided with a second pin groove; and the second eccentric bushing is provided with a third pin groove corresponding to the second pin groove. The cylindrical pin is disposed in the accommodating space formed by the first pin groove, the second pin groove and the third pin groove.

[0014] Furthermore, it also includes: a second bearing assembly and a gasket assembly; The output mechanism is sleeved on the input shaft via the second bearing assembly; The gasket assembly is sleeved on the input mechanism, the gasket assembly is connected between the first bearing assembly and the second bearing assembly, and the gasket assembly is disposed in the slit channel formed by the eccentric mechanism, the first bearing assembly, the input mechanism and the second bearing assembly.

[0015] Furthermore, the gasket assembly includes a first gasket; the first gasket is sleeved on the eccentric mechanism, and one end face of the first gasket abuts against the first bearing assembly; wherein, the outer diameter of the first gasket is greater than the center diameter of the corresponding bearing in the first bearing assembly, and smaller than the inner diameter of the outer ring of the corresponding bearing.

[0016] Furthermore, the gasket assembly also includes a second gasket; the second gasket is sleeved on the input shaft, and one end face of the second gasket abuts against the eccentric mechanism, the end of the cylindrical pin, and the other end face of the first gasket.

[0017] Furthermore, the gasket assembly also includes a third gasket; the third gasket is sleeved on the input shaft, one end face of the third gasket abuts against the other end face of the second gasket, and the other end face of the third gasket abuts against the second bearing assembly; wherein, the outer diameter of the third gasket is larger than the center diameter of the corresponding bearing in the second bearing assembly, and smaller than the inner diameter of the outer ring of the corresponding bearing.

[0018] Furthermore, it also includes: a third bearing assembly; the frame is fitted onto the output mechanism via the third bearing assembly.

[0019] This application has the following advantages: In the embodiments of this application, addressing the issue that the input structure of existing cycloidal pinwheel reducers is insufficient to meet the technical requirements for fatigue strength and oil leakage prevention, this application provides a solution using cylindrical pins to connect the input shaft and the eccentric mechanism. Specifically, the eccentric mechanism is sleeved on the input shaft via the cylindrical pins, and the cycloidal wheel mechanism is sleeved on the eccentric mechanism via the first bearing assembly. The frame includes a plurality of spaced-apart outer needle rollers; the output mechanism includes a plurality of spaced-apart inner needle rollers; the outer edge tooth profile of the cycloidal wheel mechanism meshes with the outer needle rollers, and the inner needle rollers correspondingly pass through the output hole of the cycloidal wheel mechanism. When the input shaft rotates, the input shaft drives the cycloidal wheel mechanism to perform eccentric motion via the eccentric mechanism, and the cycloidal wheel mechanism drives the output mechanism to rotate via the inner needle rollers. By using cylindrical pins to connect the input shaft and the eccentric mechanism, this application can retain a relatively closed oil leakage prevention structure while also meeting fatigue strength requirements. Attached Figure Description

[0020] To more clearly illustrate the technical solution of this application, the drawings used in the description of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the first integral structure of a cycloidal pinwheel reducer provided in an embodiment of this application; Figure 2 This is a cross-sectional view of a cycloidal pinwheel reducer provided in one embodiment of this application; Figure 3 This is a schematic diagram of the structure of an input shaft with a hollow structure in one embodiment of this application; Figure 4 Yes Figure 3 A schematic diagram of the simulation results of finite element statics simulation of the input shaft; Figure 5 This is a schematic diagram of the combined structure of the input shaft, the first eccentric bushing, and the second eccentric bushing in one embodiment of this application; Figure 6 This is an exploded structural diagram of the input shaft, the first eccentric bushing, and the second eccentric bushing in one embodiment of this application; Figure 7 This is a schematic diagram of the second integral structure of a cycloidal pinwheel reducer provided in one embodiment of this application; Figure 8 yes Figure 7 Schematic diagram of the cross-sectional structure at section A in the middle; Figure 9 This is a schematic diagram of the third integral structure of a cycloidal pinwheel reducer provided in one embodiment of this application; Figure 10 yes Figure 9 Schematic diagram of the cross-sectional structure at section B; Figure 11 This is a schematic diagram of the combined structure of the eccentric mechanism and the cycloidal wheel mechanism exploded along the axial direction in one embodiment of this application; Figure 12 yes Figure 11 Schematic diagram of the cross-sectional structure at section C; Figure 13 yes Figure 2 A magnified schematic diagram of part D in the middle section.

[0022] The attached figures are labeled as follows: 1. Input mechanism; 11. Input shaft; 111. First pin groove; 112. Annular connector; 12. Cylindrical pin; 13. Hollow structure; 2. Eccentric mechanism; 21. First eccentric bushing; 211. First eccentric wheel; 212. Second pin groove; 22. Second eccentric bushing; 221. Second eccentric wheel; 222. Third pin groove; 23. Third eccentric wheel; 3. First bearing assembly; 31. First eccentric bearing; 32. Second eccentric bearing; 33. Third eccentric bearing; 4. Cycloidal wheel mechanism; 41. First cycloidal wheel; 42. Second cycloidal wheel; 4 3. Third cycloidal wheel; 44. Output hole; 5. Output mechanism; 51. Inner needle roller; 511. First bushing; 52. First inner housing; 53. Second inner housing; 6. Frame; 61. Outer needle roller; 611. Second bushing; 62. First outer housing; 63. Second outer housing; 7. Second bearing assembly; 71. First input bearing; 72. Second input bearing; 8. Shim assembly; 81. First shim; 82. Second shim; 83. Third shim; 84. Slit channel; 9. Third bearing assembly; 91. First output bearing; 92. Second output bearing. Detailed Implementation

[0023] To make the objectives, features, and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0024] Through analysis of existing technologies, the inventors discovered that the input structure of existing cycloidal pinwheel reducers is difficult to meet the technical requirements for fatigue strength and oil leakage prevention. The fundamental reason is that, on the one hand, using a key pin and eccentric structure at the input shaft can form a relatively closed structure that is not easy to leak oil, but it will lead to stress concentration; on the other hand, although adopting a D-type input shaft can relatively reduce stress concentration, in order to meet the assemblability of the D-type input shaft, the D-type structure needs to extend from the part that mates with the eccentric structure to the end of the input shaft, which makes it easy for grease to leak.

[0025] Based on the above analysis, one of the core technical concepts of this application is that by using a cylindrical pin to connect the input shaft and the eccentric mechanism, a relatively closed oil leakage prevention structure can be maintained, while also meeting fatigue strength requirements.

[0026] Reference Figure 1-13This application illustrates a cycloidal pinwheel reducer according to an embodiment of the present application, comprising: an input mechanism 1, an eccentric mechanism 2, a first bearing assembly 3, a cycloidal wheel mechanism 4, an output mechanism 5, and a frame 6; the input mechanism 1 includes an input shaft 11 and a cylindrical pin 12; The eccentric mechanism 2 is sleeved on the input shaft 11 via the cylindrical pin 12, and the cycloidal wheel mechanism 4 is sleeved on the eccentric mechanism 2 via the first bearing assembly 3; The frame 6 is provided with a plurality of outer roller needles 61 arranged in a circumferential array; the output mechanism 5 is provided with a plurality of inner roller needles 51 arranged in a circumferential array; the outer edge tooth profile of the cycloidal wheel mechanism 4 meshes with the outer roller needles 61, and the inner roller needles 51 are correspondingly inserted through the output hole 44 of the cycloidal wheel mechanism 4. When the input shaft 11 rotates, the input shaft 11 drives the cycloidal wheel mechanism 4 to perform eccentric motion through the eccentric mechanism 2, and the cycloidal wheel mechanism 4 drives the output mechanism 5 to rotate through the inner needle roller 51.

[0027] In the embodiments of this application, addressing the issue that the input structure of existing cycloidal pinwheel reducers is insufficient to meet the technical requirements for fatigue strength and oil leakage prevention, this application provides a solution using cylindrical pins 12 to connect the input shaft 11 and the eccentric mechanism 2. Specifically, the eccentric mechanism 2 is sleeved on the input shaft 11 via the cylindrical pins 12, and the cycloidal wheel mechanism 4 is sleeved on the eccentric mechanism 2 via the first bearing assembly 3. The frame 6 is provided with a plurality of outer roller needles 61 arranged in a circumferential array; the output mechanism 5 is provided with a plurality of inner roller needles 51 arranged in a circumferential array; the outer edge tooth profile of the cycloidal wheel mechanism 4 meshes with the outer roller needles 61, and the inner roller needles 51 are correspondingly inserted into the output hole 44 of the cycloidal wheel mechanism 4. When the input shaft 11 rotates, the input shaft 11 drives the cycloidal wheel mechanism 4 to perform eccentric motion through the eccentric mechanism 2, and the cycloidal wheel mechanism 4 drives the output mechanism 5 to rotate through the inner roller needles 51. This application uses a cylindrical pin 12 to connect the input shaft 11 and the eccentric mechanism 2, which can both maintain a relatively closed oil leakage prevention structure and meet the fatigue strength requirements.

[0028] The following will further describe a cycloidal pinwheel reducer in this exemplary embodiment.

[0029] As an example, the cylindrical pin 12 may consist of only one.

[0030] As an example, the cylindrical pin 12 may also include two, with the two cylindrical pins 12 respectively disposed on opposite sides of the input shaft 11.

[0031] As an example, the cylindrical pins 12 may also include three or more, with the plurality of cylindrical pins 12 arranged in an array along the circumferential direction of the input shaft 11.

[0032] It should be noted that the input shaft 11 may have a groove that matches the shape of the cylindrical pin top. Compared with the shaft key structure, by using the cylindrical pin 12 as the transmission structure between the input shaft 11 and the eccentric mechanism 2, the maximum equivalent stress at the joint surface between the cylindrical pin 12 and the input shaft 11 is smaller. Therefore, the groove depth on the input shaft 11 is lower, and stress concentration is less likely to occur. This maximizes the hollow diameter inside the input shaft 11 while ensuring structural strength.

[0033] Reference Figure 3-4 In a specific embodiment of this application, the input shaft 11 is provided with a hollow structure 13.

[0034] In a specific implementation, refer to Figure 4 The torque of the input shaft 11 is transmitted to two eccentric bushings via two steel cylindrical pins 12 with a diameter of 1.5 mm. The outer side of the eccentric shaft is connected to the inner ring of the thin-walled bearing, and the outer ring of the thin-walled bearing is connected to the cycloidal wheel, driving the cycloidal wheel to perform eccentric cycloidal motion. Finite element static simulation of the input shaft 11 using ANSYS shows that when subjected to the peak torque (4.3 Nm) of the matching frameless torque motor, the maximum equivalent stress at the joint surface between the cylindrical pins 12 and the input shaft 11 is only 128.26 MPa. This value is much smaller than the fatigue strength (290 MPa) of the aluminum alloy material (7075) of the input shaft 11 under 3E10^6 alternating loads.

[0035] It should be noted that the hollow structure 13 allows for the weight reduction of the input shaft 11. When the reducer is used as the transmission structure of the robot, the hollow structure 13 of the input shaft 11 can also be used to pass through the robot's electrical control cables, facilitating wiring.

[0036] As an example, the hollow diameter of the input shaft 11 can be in the range of 10-30mm, and the calculation formula for the outer diameter of the input shaft 11 (corresponding to the circumference in contact with the eccentric mechanism 2) is as follows:

[0037] in, The outer diameter of input shaft 11, The diameter of cylindrical pin 12, The hollow diameter of input shaft 11; The diameter of the cylindrical pin 12 is within the range of the hollow diameter of the input shaft 11 as constrained above. The diameter of the cylindrical pin 12 can be 1-3mm, and the length of the cylindrical pin 12 can be 10-30mm.

[0038] Reference Figure 5-6 and Figure 12 In one embodiment of this application, the eccentric mechanism 2 includes a first eccentric bushing 21 and a second eccentric bushing 22; The first eccentric bushing 21 is provided with a first eccentric wheel 211; the second eccentric bushing 22 is provided with a second eccentric wheel 221; the first eccentric bushing 21 and the second eccentric bushing 22 abut against each other along the axial direction, and a third eccentric wheel 23 is formed at the abutment portion; The cycloidal wheel mechanism 4 is sleeved on the first eccentric wheel 211, the second eccentric wheel 221 and the third eccentric wheel 23 via the first bearing assembly 3.

[0039] It should be noted that the eccentric mechanism 2 consists of three corresponding eccentric wheels formed by two independent first eccentric bushings 21 and second eccentric bushings 22. To meet the dynamic balance requirements of the cycloidal wheels, the third eccentric wheel 23 must have a 180° phase angle (eccentricity) relative to the first eccentric wheel 211 and the second eccentric wheel 221. Since the third eccentric wheel 23 is formed by the contact part of the first eccentric bushing 21 and the second eccentric bushing 22, the third eccentric wheel 23 with a 180° phase angle (eccentricity) will not affect the assembly of the three cycloidal wheels.

[0040] Reference Figure 12 In one embodiment of this application, the first bearing assembly 3 includes: a first eccentric bearing 31, a second eccentric bearing 32, and a third eccentric bearing 33; The first eccentric bearing 31 is sleeved on the first eccentric wheel 211; the second eccentric bearing 32 is sleeved on the second eccentric wheel 221; and the third eccentric bearing 33 is sleeved on the third eccentric wheel 23.

[0041] It should be noted that the first eccentric bearing 31, the second eccentric bearing 32, and the third eccentric bearing 33 can all be standard thin-walled deep groove ball bearings. As a vulnerable component in a cycloidal pinwheel reducer, the eccentric bearing typically fails before the cycloidal wheel. Traditional custom-made eccentric bearings have rollers that directly contact the cycloidal wheel, easily leading to the contact surface failing before the cycloidal wheel tooth surface, thus preventing the reducer from undergoing life-extending maintenance. However, the eccentric bearing of this application uses a standard thin-walled deep groove ball bearing, with the outer ring of the eccentric bearing contacting the cycloidal wheel directly, rather than through rollers. Therefore, after the eccentric bearing fails, the standard bearing component can be directly replaced, extending the reducer's service life and saving costs.

[0042] Reference Figure 4 and Figure 10-12 In one embodiment of this application, the cycloidal wheel mechanism 4 includes a first cycloidal wheel 41, a second cycloidal wheel 42, and a third cycloidal wheel 43; The first cycloidal wheel 41 is sleeved on the first eccentric bearing 31; the second cycloidal wheel 42 is sleeved on the second eccentric bearing 32; and the third cycloidal wheel 43 is sleeved on the third eccentric bearing 33.

[0043] It should be noted that the first cycloidal wheel 41 and the second cycloidal wheel 42 may have the same phase, and the third cycloidal wheel 43 may maintain a phase difference of 180° relative to the first cycloidal wheel 41 and the second cycloidal wheel 42. The first cycloidal wheel 41 and the second cycloidal wheel 42 are respectively disposed on both sides of the third cycloidal wheel 43.

[0044] Reference Figure 5-6 In one embodiment of this application, the input shaft 11 is provided with a first pin groove 111; the first eccentric bushing 21 is provided with a second pin groove 212; and the second eccentric bushing 22 is provided with a third pin groove 222 corresponding to the second pin groove 212. The cylindrical pin 12 is disposed in the accommodating space formed by the first pin groove 111, the second pin groove 212 and the third pin groove 222.

[0045] It should be noted that when the input shaft 11 rotates, the input shaft 11 transmits torque to the cylindrical pin 12 through the first pin groove 111, and the cylindrical pin 12 transmits torque to the second pin groove 212 and the third pin groove 222 to drive the eccentric mechanism 2 to rotate, thereby driving the cycloidal wheel mechanism 4 to perform eccentric cycloidal motion.

[0046] In one specific implementation, the input mechanism 1, the eccentric mechanism 2, the first bearing assembly 3, and the cycloidal wheel mechanism 4 can be installed in the following way: A cylindrical pin 12 is installed in the first pin groove 111 of the input shaft 11. A first eccentric sleeve 21 is then fitted onto the cylindrical pin 12, such that the first pin groove 111 and the second pin groove 212 cover the outer side of the cylindrical pin 12. A first eccentric bearing 31 and a first cycloidal wheel 41 are installed at the first eccentric wheel 211 of the first eccentric sleeve 21. A third eccentric bearing 33 and a third cycloidal wheel 43 are installed at the abutment portion of the first eccentric sleeve 21 corresponding to the second eccentric sleeve 22. A second eccentric sleeve 22 is fitted onto the cylindrical pin 12, such that the first pin groove 111 and the third pin groove 222 cover the outer side of the cylindrical pin 12. The first eccentric sleeve 21 and the second eccentric sleeve 22 abut against each other to form a third eccentric wheel 23. The third eccentric bearing 33 and the third cycloidal wheel 43 correspond to the third eccentric wheel 23. A second eccentric bearing 32 and a second cycloidal wheel 42 are installed at the second eccentric wheel 221 of the second eccentric bushing 22.

[0047] It should be noted that since the third eccentric wheel 23 is formed by the abutting fit between the first eccentric bushing 21 and the second eccentric bushing 22, the installation method of first installing the third eccentric bearing 33 and the third cycloidal wheel 43 at the abutting part of the first eccentric bushing 21 and then installing the second eccentric bushing 22 can enable the three cycloidal wheels to be installed on the corresponding eccentric wheels even when there is a 180° phase difference, thus avoiding the assembly problem caused by eccentricity interference.

[0048] In a specific embodiment of this application, the outer rings of the first eccentric bearing 31 and the second eccentric bearing 32 on the side away from the third eccentric bearing 33 are provided with flange portions. The first cycloidal wheel 41 abuts against the flange portion of the first eccentric bearing 31, and the second cycloidal wheel 42 abuts against the flange portion of the second eccentric bearing 32.

[0049] Reference Figure 2 and Figure 13 In one embodiment of this application, it further includes: a second bearing assembly 7 and a gasket assembly 8; The output mechanism 5 is sleeved on the input shaft 11 via the second bearing assembly 7; The gasket assembly 8 is sleeved on the input mechanism 1, the gasket assembly 8 is connected between the first bearing assembly 3 and the second bearing assembly 7, and the gasket assembly 8 is disposed in the slit channel 84 formed by the eccentric mechanism 2, the first bearing assembly 3, the input mechanism 1 and the second bearing assembly 7.

[0050] It should be noted that the second bearing assembly 7 can be used to maintain the radial distance between the input shaft 11 and the output mechanism 5.

[0051] Both the inner needle roller 51 and the first bearing assembly 3 are provided with grease for lubrication. Since the second bearing assembly 7 is the bearing of the input shaft 11 and rotates at the highest speed, it is most prone to grease leakage. A grease slit channel 84 is formed between the first inner housing 52, the first input bearing 71, and the first eccentric bearing 31, and also between the second inner housing 53, the second input bearing 72, and the second eccentric bearing 32. By placing the corresponding gasket assembly 8 in the slit channel 84, the difficulty of grease leakage from the corresponding input bearing can be increased, thereby reducing grease leakage.

[0052] In one specific embodiment of this application, the gasket assembly 8 includes two sets, which are respectively disposed on both sides of the eccentric mechanism 2 and the first bearing assembly 3.

[0053] In one specific embodiment of this application, the gasket assembly 8 is a metal part. The thickness of each gasket in the gasket assembly 8 can be 0.2-2 mm.

[0054] It should be noted that the injection-molded gaskets used in traditional cycloidal pinwheel reducers are characterized by low cost and high tolerance for axial tolerances. However, in robot joint applications, the axial dimension (length) needs to be minimized to match the overall robot size. Traditional injection molding processes are costly when manufacturing thin-film products, and the mold opening cost is extremely high, making this process disadvantageous in the rapidly evolving robot joint market. This embodiment uses metal gaskets, which can achieve thinner dimensions at a lower cost and have a longer service life.

[0055] Reference Figure 13 In one embodiment of this application, the gasket assembly 8 includes a first gasket 81; the first gasket 81 is sleeved on the eccentric mechanism 2, and one end face of the first gasket 81 abuts against the first bearing assembly 3; wherein, the outer diameter of the first gasket 81 is greater than the center diameter of the corresponding bearing in the first bearing assembly 3, and smaller than the inner diameter of the outer ring of the corresponding bearing.

[0056] It should be noted that the first shim 81 can be used to prevent grease leakage from the eccentric bearing, and can also serve as a limiting structure for the eccentric bearing. If the outer diameter of the first shim 81 is larger than the inner diameter of the outer ring of the eccentric bearing, the first shim 81 will rub against the outer ring of the eccentric bearing and cause damage, because the first shim 81 will move eccentrically in coordination with the inner ring of the eccentric bearing.

[0057] Reference Figure 13 In one embodiment of this application, the gasket assembly 8 further includes a second gasket 82; the second gasket 82 is sleeved on the input shaft 11, and one end face of the second gasket 82 abuts against the end of the eccentric mechanism 2, the cylindrical pin 12 and the other end face of the first gasket 81.

[0058] It should be noted that the second gasket 82 can serve as an axial limiting structure for the eccentric mechanism 2, the cylindrical pin 12, and the first gasket 81. The second gasket 82 is positioned between the first gasket 81 and the third gasket 83, forming the main structure of the gasket assembly 8 to maximize the blockage of the grease slit channel 84. The thickness of the second gasket 82 should be designed to avoid friction with the inner wall of the output mechanism 5. The outer diameter of the second gasket 82 must be greater than the inner diameter of the eccentric bearing plus twice the eccentricity of the cycloidal wheel, calculated using the following formula:

[0059] in, The outer diameter of the second gasket 82 For the eccentricity of the cycloidal wheel, This is the inner diameter of the eccentric bearing.

[0060] Reference Figure 13 In one embodiment of this application, the gasket assembly 8 further includes a third gasket 83; the third gasket 83 is sleeved on the input shaft 11, one end face of the third gasket 83 abuts against the other end face of the second gasket 82, and the other end face of the third gasket 83 abuts against the second bearing assembly 7; wherein, the outer diameter of the third gasket 83 is larger than the center diameter of the corresponding bearing in the second bearing assembly 7, and smaller than the inner diameter of the outer ring of the corresponding bearing.

[0061] It should be noted that the third gasket 83 serves as an intermediate component to prevent the second gasket 82 from making frictional contact with the input bearing. The third gasket 83 is used to prevent grease from entering the input bearing through the slit channel 84, thus preventing grease leakage. If the outer diameter of the third gasket 83 is larger than the inner diameter of the outer ring of the input bearing, the third gasket 83 will rub against the outer ring of the input bearing, causing damage, because it will move in tandem with the inner ring of the input bearing.

[0062] Reference Figure 8 In a specific embodiment of this application, the second bearing assembly 7 includes a first input bearing 71 and a second input bearing 72; one side of the first input bearing 71 abuts against the shoulder of the input shaft 11 and the limiting structure inside the output mechanism 5, and the other side of the first input bearing 71 abuts against the gasket assembly 8 near the first eccentric bushing 21; one end of the input shaft 11 is provided with an annular connector 112 for axially limiting the components of the input shaft 11, one side of the second input bearing 72 abuts against the annular connector 112 of the input shaft 11, and the other side of the second input bearing 72 abuts against the gasket assembly 8 near the second eccentric bushing 22.

[0063] Reference Figure 2 In one embodiment of this application, it further includes: a third bearing assembly 9; the frame 6 is sleeved on the output mechanism 5 through the third bearing assembly 9.

[0064] It should be noted that the third bearing assembly 9 can be used to maintain the radial distance between the output mechanism 5 and the frame 6.

[0065] Reference Figure 2 and Figure 8 In a specific embodiment of this application, the third bearing assembly 9 includes a first output bearing 91 and a second output bearing 92. One side of the first output bearing 91 abuts against a limiting structure on the outside of the output mechanism 5, and the other side of the first output bearing 91 abuts against a limiting structure on the inside of the frame 6.

[0066] Reference Figure 2 and Figure 7-9In one specific embodiment of this application, the frame 6 includes a first outer shell 62 and a second outer shell 63 adapted thereto. The second outer shell 63 is disposed on the side of the first outer shell 62 away from the input end of the input mechanism 1. The first outer shell 62 and the second outer shell 63 are connected by screws. The inner sides of the first outer shell 62 and the second outer shell 63 are respectively provided with openings for accommodating both ends of the outer roller needle 61. One end of the outer roller needle 61 is connected to the opening of the first outer shell 62 through a second bushing 611, and the other end of the outer roller needle 61 is connected to the opening of the second outer shell 63 through a second bushing 611. Each outer roller needle 61 corresponds to two second bushings 611, and the second bushings 611 are respectively disposed in the openings of the first outer shell 62 and the second outer shell 63.

[0067] Reference Figure 2 and Figure 7-9 In a specific embodiment of this application, the output mechanism 5 includes a first inner housing 52 and a second inner housing 53 adapted thereto. The second inner housing 53 is disposed on the side of the first inner housing 52 away from the input end of the input mechanism 1, and the second inner housing 53 may have an opening for output torque. The inner sides of the first inner housing 52 and the second inner housing 53 are respectively provided with openings for accommodating both ends of the inner roller needle 51; one end of the inner roller needle 51 is connected to the opening of the first outer housing 62, and the other end of the inner roller needle 51 is connected to the opening of the second outer housing 63; a first bushing 511 is provided on the outer side of the inner roller needle 51, and the first bushing 511 is disposed between the first inner housing 52 and the second inner housing 53. The output hole 44 of the cycloidal wheel mechanism 4 is connected to the inner roller needle 51 through the first bushing 511.

[0068] It should be noted that the inner needle roller 51 can be used to support the first bushing 511, allowing the first bushing 511 to have pure rolling friction with the cycloidal wheel. The inner needle roller 51 and the first bushing 511 are equivalent to a bushing bearing that experiences sliding friction. Compared to the inner needle roller 51, which is similar to a cantilever beam structure, the inner needle roller 51 in this embodiment is equivalent to a more stable simply supported beam structure that smoothly transmits the output torque to the first inner housing 52 and the second inner housing 53, reducing the failure of the inner needle roller 51 due to bending fatigue.

[0069] In the above embodiments of this application, a cylindrical pin 12 is used instead of a traditional flat key pin or D-type shaft to transmit torque from the input shaft 11. This reduces the stress concentration at the root of the traditional flat key pin groove, while also reducing volume and increasing the diameter of the hollow cable routing hole in the reducer. The use of a two-section eccentric bushing and a three-piece shim combination as the axial constraint method for the cycloidal wheel reduces production and assembly costs and minimizes efficiency loss caused by the agitation of lubricating grease inside the reducer.

[0070] Although preferred embodiments of the present application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present application.

[0071] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0072] The above provides a detailed description of a cycloidal pinwheel reducer provided in this application. Specific examples have been used to illustrate the principle and implementation of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​this application. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A cycloidal pinwheel reducer, characterized in that, include: The system comprises an input mechanism, an eccentric mechanism, a first bearing assembly, a cycloidal wheel mechanism, an output mechanism, and a frame; the input mechanism includes an input shaft and a cylindrical pin. The eccentric mechanism is sleeved on the input shaft via the cylindrical pin, and the cycloidal wheel mechanism is sleeved on the eccentric mechanism via the first bearing assembly; The frame includes a plurality of spaced-out outer roller needles; the output mechanism includes a plurality of spaced-out inner roller needles; the outer edge tooth profile of the cycloidal wheel mechanism meshes with the outer roller needles, and the inner roller needles are correspondingly inserted into the output hole of the cycloidal wheel mechanism; When the input shaft rotates, the input shaft drives the cycloidal wheel mechanism to perform eccentric motion through the eccentric mechanism, and the cycloidal wheel mechanism drives the output mechanism to rotate through the inner needle roller.

2. The reducer according to claim 1, characterized in that, The eccentric mechanism includes a first eccentric bushing and a second eccentric bushing; The first eccentric bushing is provided with a first eccentric wheel; the second eccentric bushing is provided with a second eccentric wheel; the first eccentric bushing and the second eccentric bushing abut against each other along the axial direction, and a third eccentric wheel is formed at the abutment portion; The cycloidal wheel mechanism is sleeved on the first eccentric wheel, the second eccentric wheel, and the third eccentric wheel via the first bearing assembly.

3. The reducer according to claim 2, characterized in that, The first bearing assembly includes: a first eccentric bearing, a second eccentric bearing, and a third eccentric bearing; The first eccentric bearing is sleeved on the first eccentric wheel; the second eccentric bearing is sleeved on the second eccentric wheel; and the third eccentric bearing is sleeved on the third eccentric wheel.

4. The reducer according to claim 3, characterized in that, The cycloidal wheel mechanism includes a first cycloidal wheel, a second cycloidal wheel, and a third cycloidal wheel; The first cycloidal wheel is sleeved on the first eccentric bearing; the second cycloidal wheel is sleeved on the second eccentric bearing; and the third cycloidal wheel is sleeved on the third eccentric bearing.

5. The reducer according to claim 2, characterized in that, The input shaft is provided with a first pin groove; the first eccentric bushing is provided with a second pin groove; the second eccentric bushing is provided with a third pin groove corresponding to the second pin groove; The cylindrical pin is disposed in the accommodating space formed by the first pin groove, the second pin groove and the third pin groove.

6. The reducer according to claim 1, characterized in that, Also includes: Second bearing assembly and gasket assembly; The output mechanism is sleeved on the input shaft via the second bearing assembly; The gasket assembly is sleeved on the input mechanism, the gasket assembly is connected between the first bearing assembly and the second bearing assembly, and the gasket assembly is disposed in the slit channel formed by the eccentric mechanism, the first bearing assembly, the input mechanism and the second bearing assembly.

7. The reducer according to claim 6, characterized in that, The gasket assembly includes a first gasket; the first gasket is sleeved on the eccentric mechanism, and one end face of the first gasket abuts against the first bearing assembly; wherein, the outer diameter of the first gasket is greater than the center diameter of the corresponding bearing in the first bearing assembly, and smaller than the inner diameter of the outer ring of the corresponding bearing.

8. The reducer according to claim 7, characterized in that, The gasket assembly further includes a second gasket; the second gasket is sleeved on the input shaft, and one end face of the second gasket abuts against the eccentric mechanism, the end of the cylindrical pin, and the other end face of the first gasket.

9. The reducer according to claim 8, characterized in that, The gasket assembly further includes a third gasket; the third gasket is sleeved on the input shaft, one end face of the third gasket abuts against the other end face of the second gasket, and the other end face of the third gasket abuts against the second bearing assembly; wherein, the outer diameter of the third gasket is larger than the center diameter of the corresponding bearing in the second bearing assembly, and smaller than the inner diameter of the outer ring of the corresponding bearing.

10. The reducer according to claim 1, characterized in that, Also includes: The third bearing assembly; the frame is fitted onto the output mechanism via the third bearing assembly.

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