Cycloidal gear transmission assembly, speed reducer and industrial robot

Abstract

The invention discloses a cycloidal gear transmission assembly, a speed reducer and an industrial robot. The cycloidal gear transmission assembly comprises a pin gear, a cycloidal gear and a crankshaft. A through hole is formed in the cycloid gear, the crankshaft comprises a crankshaft body and a flange, the flange protrudes around the circumferential direction of the crankshaft body, the axis of the crankshaft body is parallel to the axis of the flange, the cycloid gear is arranged on the flange in a sleeving mode through the through hole, the pin gear is meshed with the cycloid gear, the pin gear comprises a plurality of cylindrical pin teeth, and the distance between the axis of the flange and the axis of the crankshaft body is H, the radius of each pin tooth is R, and the value range of H / R is [0.46, 0.49]. According to the cycloid gear transmission assembly, the ratio of the distance between the axis of the flange and the axis of the shaft body to the radius of the pin gear is limited to be 0.46-0.49, the output torque of the transmission assembly can be improved, meanwhile, interference between the cycloid gear and the pin gear housing is avoided, the contact stress of parts is small, and the cycloid gear transmission assembly has good impact resistance.

Description

Technical Field

[0001] The invention relates to the technical field of reducers, and in particular to a cycloid gear transmission assembly, a reducer and an industrial robot. Background Art

[0002] Precision planetary cycloid reducer is the core component of industrial robots, with the advantages of high precision, high rigidity and long life. Precision planetary cycloid reducer contains two-stage reduction parts, the first part is the involute gear planetary transmission assembly, and the second part is the cycloid pinwheel planetary transmission assembly. Among them, the component size design of the cycloid pinwheel planetary transmission assembly is an important part of the whole machine design. Improper component size design may cause interference between the cycloid gear and the pinion housing, excessive contact stress of the parts, and thus reduce the life of the reducer. Summary of the invention

[0003] The embodiments of the present invention provide a cycloid gear transmission assembly, a reducer and an industrial robot to solve at least one of the above-mentioned technical problems.

[0004] A cycloid gear transmission assembly according to an embodiment of the present invention includes a pinion gear, a cycloid gear and a crank shaft.

[0005] The cycloid gear has a through hole, and the crank shaft includes a shaft body and a flange. The flange is a circumferential protrusion around the shaft body, and the axis of the shaft body is parallel to the axis of the flange. The cycloid gear is sleeved with the flange through the through hole, and the pin-tooth gear is meshed with the cycloid gear. The pin-tooth gear includes a plurality of cylindrical pin teeth, and the distance between the axis of the flange and the axis of the shaft body is H, and the radius of the pin teeth is R, wherein the value range of H / R is [0.46, 0.49].

[0006] The above-mentioned cycloid gear transmission assembly limits the ratio of the distance between the axis of the flange and the axis of the shaft body to the radius of the pin tooth to between 0.46 and 0.49, which can improve the output torque of the transmission assembly, while avoiding interference between the cycloid gear and the pin tooth housing, reducing the contact stress of the parts and making the cycloid gear transmission assembly have better impact resistance.

[0007] In some embodiments, the pin tooth housing is in the shape of a ring, and the pin teeth are arranged at equal intervals around the inner wall surface of the pin tooth housing. At the position where the pin tooth gear and the cycloid gear are meshed, the distance between the convergence point of the force of the pin teeth on the cycloid gear and the center of the cycloid gear is L, and the radius of the circle formed by the center of the pin teeth is Q, and the value range of L / Q is [0.6, 0.9].

[0008] In certain embodiments, when the pin-tooth gear meshes and rotates with the cycloid gear, the number of teeth of the outer tooth portion of the cycloid gear that participates in the meshing is equal to one eighth of the total number of teeth of the cycloid gear.

[0009] In some embodiments, the flange includes a first flange and a second flange, the distance between the axis of the first flange and the axis of the shaft body is equal to the distance between the axis of the second flange and the axis of the shaft body, and the cycloid gear includes a first cycloid gear and a second cycloid gear, the first cycloid gear is sleeved on the first flange, and the second cycloid gear is sleeved on the second flange.

[0010] In some embodiments, the direction in which the axis of the first flange deviates from the axis of the shaft body differs from the direction in which the axis of the second flange deviates from the axis of the shaft body by 180°.

[0011] In some embodiments, the cycloid gear transmission assembly includes three crankshafts, the cycloid gear is provided with three through holes to respectively pass the three crankshafts, the three through holes are arranged around the center of the cycloid gear and the centers of the three through holes are respectively spaced 120° apart.

[0012] In certain embodiments, the cycloid gear transmission assembly further includes a needle bearing, and the needle bearing is disposed between the cycloid gear and the crank shaft.

[0013] A reducer in an embodiment of the present invention includes a cycloidal gear transmission assembly and a planetary gear transmission assembly as described in any one of the above embodiments, wherein the planetary gear transmission assembly includes a sun gear and planetary gears, wherein the sun gear is connected to the output shaft of the motor, the sun gear is meshed with the planetary gears for transmission, and the planetary gears are connected to the crankshaft for transmission.

[0014] In some embodiments, the reducer further includes a limit assembly, which is disposed on the crankshaft and abuts against the planetary gear to limit the movement of the planetary gear along the axis of the crankshaft.

[0015] An industrial robot according to an embodiment of the present invention comprises the reducer described in any one of the above embodiments.

[0016] The above reducer and industrial robot limit the ratio of the distance between the axis of the flange and the axis of the shaft body to the radius of the pin teeth to between 0.46 and 0.49, which can improve the output torque of the transmission component and ensure that the reducer has good impact resistance. At the same time, the contact stress between the cycloid gear and the pin teeth is small, so that the reducer has a longer service life.

[0017] 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

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0019] Figure 1 is a schematic structural diagram of a cycloid gear and a pin gear according to an embodiment of the present invention;

[0020] Figure 2 It is a partial structural schematic diagram of a reducer according to an embodiment of the present invention.

[0021] Description of main component symbols:

[0022] Cycloid gear transmission assembly-10, pin gear-12, cycloid gear-14, first cycloid gear-14a, second cycloid gear-14b, crank shaft-16, through hole-18, shaft body-20, flange-22, first flange-22a, second flange-22b, pin gear-24, pin gear housing-26, needle roller bearing-28, planetary gear-30.

[0023] Reducer -100. DETAILED DESCRIPTION

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] See also Figure 1 and Figure 2 A cycloid gear transmission assembly 10 provided in an embodiment of the present invention includes a pin gear 12 , a cycloid gear 14 and a crank shaft 16 .

[0030] The cycloid gear 14 has a through hole 18, and the crank shaft 16 includes a shaft body 20 and a flange 22. The flange 22 is a circumferential protrusion around the shaft body 20, and the axis of the shaft body 20 is parallel to the axis of the flange 22. The cycloid gear 14 is sleeved with the flange 22 through the through hole 18. The pin-tooth gear 12 is meshed with the cycloid gear 14. The pin-tooth gear 12 includes a plurality of cylindrical pin-tooths 24. The ratio H / R of the distance H from the axis of the flange 22 to the axis of the shaft body 20 to the radius R of the pin-tooth 24 is in the range of [0.46, 0.49].

[0031] The above-mentioned cycloid gear transmission assembly 10 limits the ratio of the distance between the axis of the flange 22 and the axis of the shaft body 20 to the radius of the pin tooth 24 to between 0.46 and 0.49, which can improve the output torque of the transmission assembly, while avoiding interference between the cycloid gear 14 and the pin tooth housing 26, reducing the contact stress of the parts and making the cycloid gear transmission assembly 10 have better impact resistance.

[0032] Specifically, the cycloid gear transmission assembly 10 can be applied to the reducer 100. Optionally, the reducer 100 can be an RV (Rotary Vector) reducer. The RV reducer is a core component of an industrial robot and has the advantages of high precision, high rigidity and long life. The RV reducer is composed of a planetary gear transmission assembly and a cycloid gear transmission assembly 10.

[0033] The motion transmission path of the RV reducer 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 will make the same motion as the planetary gears. The cycloid gear 14 has a through hole 18, and the cycloid gear 14 is sleeved on the flange 22 of the crankshaft 16 through the through hole 18. Since the axis of the flange 22 and the axis of the shaft body 20 have a certain distance H, the crankshaft 16 will drive the cycloid gear 14 to make eccentric motion and mesh with the pin teeth 24, and finally transmit the load and motion to the output shaft.

[0034] For the RV reducer, it is necessary to have a larger output torque. Therefore, the output torque can be increased by designing the eccentricity of the cycloid gear transmission assembly 10. The eccentricity, that is, the distance between the axis of the flange 22 and the axis of the shaft body 20 is H, and the radius of the needle tooth 24 is R. The larger the ratio of the eccentricity to the radius of the needle tooth 24 (that is, the value of H / R), the greater the output torque, but when the value of H / R exceeds 0.5, it will cause interference between the cycloid gear 14 and the needle gear housing 26. In the related art, in order to reduce the interference between the cycloid gear 14 and the needle gear 12, it is necessary to modify the tooth profile of the cycloid gear 14, so that when the cycloid gear 14 is meshed with the needle gear 12, the number of teeth participating in the meshing is reduced, thereby causing the impact resistance of the cycloid gear transmission assembly 10 to decrease, which will cause the contact stress of the parts in the reducer to be excessive, thereby reducing the life of the entire machine.

[0035] A cycloid gear transmission assembly 10 provided in an embodiment of the present invention limits the ratio H / R between the distance H between the axis of the flange 22 and the axis of the shaft body 20 and the radius R of the pin tooth 24 to between 0.46 and 0.49. Specifically, H / R can be 0.46, 0.47, 0.48 or 0.49, or any value within the range [0.46, 0.49]. When H / R is less than 0.46, the output torque of the cycloid gear transmission assembly 10 is small and cannot meet the requirements for high-precision equipment such as RV reducers. When H / R is greater than 0.49, interference between the cycloid gear 14 and the pin tooth housing 26 will result, thereby reducing the impact resistance of the cycloid gear transmission assembly 10.

[0036] In some embodiments, the pin tooth housing 26 is in the shape of a ring, and the pin teeth 24 are arranged at equal intervals around the inner wall surface of the pin tooth housing 26. At the position where the pin tooth gear 12 and the cycloid gear 14 are meshed, the distance between the convergence point of the force of the pin teeth 24 on the cycloid gear 14 and the center of the cycloid gear 14 is L, the radius of the circle formed by the inner wall surface of the pin tooth housing 26 is Q, and the ratio L / Q has a value range of [0.6, 0.9].

[0037] In this way, the contact stress on the tooth surface of the cycloid gear 14 can be reduced, thereby increasing the life of the cycloid gear 14 .

[0038] Specifically, the pin gear housing 26 is annular, and the pin teeth 24 are arranged at equal intervals around the inner wall surface of the pin gear housing 26. The cycloid gear 14 meshes with the pin teeth 24, as shown in FIG. Figure 2 As shown, at each meshing position, the convergence point of the force exerted by the pin teeth 24 on the cycloid gear 14 is marked as point C on the cycloid gear 14, the distance between point C and the center O of the cycloid gear 14 is L, the radius of the circle formed by the center of the pin teeth 24 is Q, and the ratio L / Q has a value range of [0.6, 0.9].

[0039] For example, the ratio L / Q can be 0.6, 0.7, 0.8 or 0.9, or any value in the range [0.6, 0.9]. When the ratio L / Q is less than 0.6 or greater than 0.9, the contact stress on the tooth surface of the cycloid gear 14 will be too high, affecting the life of the cycloid gear 14; at the same time, considering the requirements for miniaturization of the cycloid gear transmission assembly 10 and the coordination with other components, limiting the ratio L / Q to the range [0.6, 0.9] is conducive to improving the life of the cycloid gear 14.

[0040] In some embodiments, when the pin-tooth gear 12 meshes and rotates with the cycloid gear 14 , the number of teeth of the outer teeth of the cycloid gear 14 that participate in the meshing is equal to one eighth of the total number of teeth of the cycloid gear 14 .

[0041] In this way, the cycloid gear transmission assembly 10 has a stronger impact resistance.

[0042] Specifically, when the toothed gear meshes with the cycloid gear 14 and rotates, the outer teeth of the cycloid gear 14 mesh with the pin teeth 24 of the pin gear 12. When the ratio H / R is between 0.46 and 0.49, theoretically, the number of teeth of the outer teeth meshing can reach half of the total number of teeth of the cycloid gear 14, while when the ratio H / R is greater than 0.5, the number of teeth of the outer teeth meshing can reach half of the total number of teeth of the cycloid gear 14.

[0043] In actual processing and application, due to processing and assembly errors, the number of teeth of the outer teeth of the cycloid gear 14 participating in meshing is equal to one eighth of the total number of teeth of the cycloid gear 14. However, the number of teeth of the outer teeth of the cycloid gear 14 participating in meshing with a ratio H / R greater than 0.5 cannot reach one eighth of the total number of teeth of the cycloid gear 14.

[0044] See also Figure 2 In some embodiments, the flange 22 includes a first flange 22a and a second flange 22b, the distance between the axis of the first flange 22a and the axis of the shaft body 20 is equal to the distance between the axis of the second flange 22b and the axis of the shaft body 20, and the cycloid gear 14 includes a first cycloid gear 14a and a second cycloid gear 14b, the first cycloid gear 14a is sleeved on the first flange 22a, and the second cycloid gear 14b is sleeved on the second flange 22b.

[0045] In this way, the impact resistance of the cycloid gear transmission assembly 10 can be improved.

[0046] Specifically, the distance between the axis of the first flange 22a and the axis of the shaft body 20 is equal to the distance between the axis of the second flange 22b and the axis of the shaft body 20. The first cycloid gear 14a is sleeved on the first flange 22a, and the second cycloid gear 14b is sleeved on the second flange 22b. Therefore, when the crankshaft 16 rotates, the eccentricity of the eccentric rotation of the first cycloid gear 14a and the second cycloid gear 14b is the same.

[0047] In some embodiments, the direction in which the axis of the first flange 22 a deviates from the axis of the shaft body 20 differs from the direction in which the axis of the second flange 22 b deviates from the axis of the shaft body 20 by 180°.

[0048] In this way, the first cycloid gear 14a and the second cycloid gear 14b are sleeved on the crankshaft 16 with a difference of 180°, thereby improving the impact resistance of the cycloid gear transmission assembly 10, while reducing the radial runout of the crankshaft 16 and improving the safety factor.

[0049] Specifically, the distance between the axis of the first flange 22a and the axis of the shaft body 20 is equal to the distance between the axis of the second flange 22b and the axis of the shaft body 20, that is, the first cycloid gear 14a and the second cycloid gear 14b will have an eccentricity compared to the axis of the crankshaft 16 when rotating. Therefore, there will be an eccentric force when the crankshaft 16 rotates.

[0050] The eccentric force will increase the moment of inertia, causing radial runout of the crankshaft 16. The first cycloid gear 14a and the second cycloid gear 14b are mounted on the crankshaft 16 with a difference of 180°. When the crankshaft 16 rotates, the movement directions of the first cycloid gear 14a and the second cycloid gear 14b are opposite, which can effectively prevent the radial runout of the crankshaft 16 and enhance the impact resistance of the cycloid gear transmission assembly 10.

[0051] In some embodiments, the cycloid gear transmission assembly 10 includes three crank shafts 16, and the cycloid gear 14 has three through holes 18 for respectively passing the three crank shafts 16, and the three through holes 18 are arranged around the center of the cycloid gear 14 and the centers of the three through holes 18 are spaced 120 degrees apart.

[0052] In this way, the forces at various locations on the crankshaft 16 , the cycloid gear 14 , and the pin-tooth gear 12 can be evenly distributed.

[0053] Specifically, the cycloid gear transmission assembly 10 includes three crankshafts 16, three through holes 18 are arranged around the center of the cycloid gear 14, and the centers of the three through holes 18 are spaced 120 degrees apart, and the cycloid gear 14 has three through holes 18 to respectively pass through the three crankshafts 16. Through the transmission of the three crankshafts 16, the forces on the crankshafts 16, the cycloid gear 14, and the pin gear 12 can be uniform.

[0054] In certain embodiments, the cycloid gear transmission assembly 10 further includes a needle bearing 28 disposed between the cycloid gear 14 and the crankshaft 16 .

[0055] In this way, the friction force when the crankshaft 16 rotates relative to the cycloid gear 14 can be reduced, thereby reducing the wear of the cycloid gear 14 and the crankshaft 16.

[0056] Specifically, the needle bearing 28 is disposed in the through hole 18 of the cycloid gear 14, the cycloid gear 14 is sleeved on the crankshaft 16, and the needle bearing 28 is located between the cycloid gear 14 and the crankshaft 16. When the crankshaft 16 rotates, the needle bearing 28 can effectively reduce the friction force when the crankshaft 16 rotates relative to the cycloid gear 14, thereby reducing the wear of the cycloid gear 14 and the crankshaft 16.

[0057] In summary, the cycloid gear transmission assembly 10 provided in the embodiment of the present invention first limits the ratio of the distance between the axis of the flange 22 and the axis of the shaft body 20 to the radius of the pin tooth 24 to between 0.46 and 0.49, which can improve the output torque of the transmission assembly and avoid the interference between the cycloid gear 14 and the pin tooth housing 26; secondly, the distance between the convergence point of the force of the pin tooth 24 on the cycloid gear 14 and the center of the cycloid gear 14 is limited to L and the radius of the circle formed by the inner wall surface of the pin tooth housing 26 is Q. The ratio is between 0.6 and 0.9, which can have a lower contact stress, improve the impact resistance of the cycloid gear transmission assembly 10, and help to extend the service life of the cycloid gear transmission assembly 10. Through the above-mentioned size limitation, the cycloid gear transmission assembly 10 has achieved a compromise between the increase in output torque and the decrease in impact resistance to a certain extent.

[0058] A speed reducer 100 according to an embodiment of the present invention comprises a cycloid gear transmission assembly 10 and a planetary gear transmission assembly according to any one of the above embodiments. The planetary gear transmission assembly comprises a sun gear (not shown) and a planetary gear 30, wherein the sun gear is connected to the output shaft of the motor, the sun gear is meshed with the planetary gear 30 for transmission, and the planetary gear 30 is connected to the crankshaft 16 for transmission.

[0059] Specifically, the motor output shaft is connected to the sun gear, and the number of planetary gears 30 corresponds to the number of crankshafts 16. In the case of multiple planetary gears 30, the multiple planetary gears 30 are arranged around the sun gear at equal intervals and mesh with the sun gear to form a first-stage reduction transmission mechanism. The planetary gears 30 are fixedly connected to the crankshaft 16, and the cycloid gear 14 is sleeved on a convex portion with a certain eccentricity on the crankshaft 16. At the same time, the cycloid gear 14 meshes with the pin gear 12 with cylindrical internal teeth, thereby forming a second-stage reduction transmission mechanism. Through the two-stage reduction transmission design, a reduction transmission with a large difference between the input speed and the output speed is achieved.

[0060] In some embodiments, the reducer 100 further includes a limit assembly, which is disposed on the crankshaft 16 and abuts against the planetary gear to limit the movement of the planetary gear along the axis of the crankshaft 16 .

[0061] In this way, the position between the crankshaft 16 and the planetary gear can be fixed, and the transmission accuracy of the speed reducer 100 can be maintained.

[0062] Specifically, the limiting assembly can prevent the planetary gear from moving along the axial direction of the crankshaft 16, thereby affecting the transmission accuracy of the reducer and even causing the reducer to fail.

[0063] An industrial robot according to an embodiment of the present invention includes the reducer 100 according to any one of the above embodiments.

[0064] The above-mentioned reducer 100 and industrial robot limit the ratio of the distance between the axis of the flange 22 and the axis of the shaft body 20 to the radius of the pin teeth 24 to between 0.46 and 0.49, which can improve the output torque of the transmission component and ensure that the reducer has good impact resistance. At the same time, the contact stress between the cycloid gear 14 and the pin teeth 24 is small, so that the reducer has a longer service life.

[0065] It should be noted that the above explanation of the implementation and beneficial effects of the cycloid gear transmission assembly 10 is also applicable to the reducer 100 and the industrial robot used in the implementation of the present invention, and will not be elaborated here in order to avoid redundancy.

[0066] 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.

[0067] 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 cycloid gear transmission assembly, characterized in that: It includes a pinion gear, a cycloid gear and a crank shaft, wherein the cycloid gear has a through hole, and the crank shaft includes a shaft body and a flange, wherein the flange is a circumferential protrusion around the shaft body, and the axis of the shaft body is parallel to the axis of the flange, and the cycloid gear is sleeved with the flange through the through hole, and the pinion gear is meshed with the cycloid gear, and the pinion gear includes a plurality of cylindrical pinions, and the distance between the axis of the flange and the axis of the shaft body is H, and the radius of the pinions is R, wherein the value range of H / R is [0.46, 0.49].

2. The cycloid gear transmission assembly according to claim 1, characterized in that: The pin gear housing is in the shape of a ring, and the pin teeth are arranged at equal intervals around the inner wall surface of the pin gear housing. At the position where the pin gear and the cycloid gear are meshed, the distance between the convergence point of the force of the pin teeth on the cycloid gear and the center of the cycloid gear is L, and the radius of the circle formed by the center of the pin teeth is Q, and the value range of L / Q is [0.6, 0.9].

3. The cycloid gear transmission assembly according to claim 1, characterized in that: When the pin-tooth gear meshes and rotates with the cycloid gear, the number of teeth of the outer tooth portion of the cycloid gear that participates in the meshing is equal to one eighth of the total number of teeth of the cycloid gear.

4. The cycloid gear transmission assembly according to claim 1, characterized in that: The flange includes a first flange and a second flange, the distance between the axis of the first flange and the axis of the shaft body is equal to the distance between the axis of the second flange and the axis of the shaft body, the cycloid gear includes a first cycloid gear and a second cycloid gear, the first cycloid gear is sleeved on the first flange, and the second cycloid gear is sleeved on the second flange.

5. The cycloid gear transmission assembly according to claim 4, characterized in that: The direction in which the axis of the first flange deviates from the axis of the shaft body differs from the direction in which the axis of the second flange deviates from the axis of the shaft body by 180°.

6. The cycloid gear transmission assembly according to claim 1, characterized in that: The cycloid gear transmission assembly includes three crankshafts. The cycloid gear is provided with three through holes for respectively passing the three crankshafts. The three through holes are arranged around the center of the cycloid gear and the centers of the three through holes are spaced 120 degrees apart.

7. The cycloid gear transmission assembly according to claim 1, characterized in that: The cycloid gear transmission assembly further includes a needle roller bearing, which is arranged between the cycloid gear and the crankshaft.

8. A reducer, characterized in that: It comprises the cycloid gear transmission assembly and the planetary gear transmission assembly as described in any one of claims 1 to 7, wherein the planetary gear transmission assembly comprises a sun gear and planetary gears, wherein the sun gear is connected to the output shaft of the motor, the sun gear meshes with the planetary gears for transmission, and the planetary gears are connected to the crankshaft for transmission.

9. The reducer according to claim 8, characterized in that: The reducer further comprises a limit assembly, which is arranged on the crankshaft and abuts against the planetary gear to limit the movement of the planetary gear along the axis direction of the crankshaft.

10. An industrial robot, characterized in that: Including the reducer described in claim 8 or 9.

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