CN220816434U - Cycloidal gear transmission assembly, speed reducer and industrial robot - Google Patents

Abstract

The utility model discloses a cycloidal gear transmission assembly, a speed reducer and an industrial robot. The cycloid gear is provided with a through hole, the crank shaft comprises a shaft body and a flange, the flange is protruded around the circumferential direction of the shaft body, 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, the pin gear is meshed with the cycloid gear, the pin gear comprises a plurality of cylindrical pin teeth, the distance between the axis of the flange and the axis of the shaft body is H, the radius of the pin teeth is R, and the value range of H/R is [0.46,0.49]. According to the cycloidal gear transmission assembly, the ratio of the distance from the axis of the flange to the axis of the shaft body to the radius of the needle teeth is limited to be 0.46-0.49, so that the output torque of the transmission assembly can be improved, the interference between the cycloidal gear and the needle tooth shell is avoided, the contact stress of parts is small, and the cycloidal gear transmission assembly has good shock resistance.

Description

Cycloidal gear transmission assembly, speed reducer and industrial robot

Technical Field

The utility model relates to the technical field of speed reducers, in particular to a cycloidal gear transmission assembly, a speed reducer and an industrial robot.

Background

The precise planetary cycloid reducer is a core part of an industrial robot and has the advantages of high precision, high rigidity, long service life and the like. The precise planetary cycloidal reducer comprises two stages of speed reducing parts, wherein the first part is an involute gear planetary transmission assembly, and the second part is a cycloidal pin gear planetary transmission assembly. The size design of the components of the cycloidal pin gear planetary transmission assembly is an important link of the whole machine design. Improper component sizing may result in interference of the cycloidal gears with the pin gear housing and excessive contact stresses on the parts, thereby reducing the speed reducer life.

Disclosure of utility model

The embodiment of the utility model provides a cycloidal gear transmission assembly, a speed reducer and an industrial robot to solve at least one technical problem.

A cycloidal gear transmission assembly according to an embodiment of the present utility model includes a pin gear, a cycloidal gear, and a crank shaft.

The cycloidal gear is provided with a through hole, the crank shaft comprises a shaft body and a flange, the flange protrudes around the circumference of the shaft body, the axis of the shaft body is parallel to the axis of the flange, the cycloidal gear is sleeved with the flange through the through hole, the pin gear is meshed with the cycloidal gear, the pin gear comprises a plurality of cylindrical pin teeth, the distance from the axis of the flange to the axis of the shaft body is H, the radius of the pin teeth is R, and the value range of H/R is [0.46,0.49].

According to the cycloidal gear transmission assembly, the ratio of the distance from the axis of the flange to the axis of the shaft body to the radius of the needle teeth is limited to be 0.46-0.49, so that the output torque of the transmission assembly can be improved, meanwhile, the interference between the cycloidal gear and the needle tooth shell is avoided, the contact stress of parts is small, and the cycloidal gear transmission assembly has good shock resistance.

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

In some embodiments, the number of teeth of the cycloidal gear engaged with the external tooth portion of the cycloidal gear when the pin gear is engaged with the cycloidal gear to rotate is equal to one eighth of the total number of teeth of the cycloidal gear.

In some embodiments, the flange includes a first flange and a second flange, a distance between an axis of the first flange and an axis of the shaft body is equal to a distance between an axis of the second flange and an 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.

In some embodiments, the direction of the axis of the first flange offset from the axis of the shaft differs from the direction of the axis of the second flange offset from the axis of the shaft by 180 °.

In some embodiments, the cycloidal gear transmission assembly includes three crankshafts, the cycloidal gear is provided with three through holes to respectively pass through the three crankshafts, the three through holes are arranged around the circle center of the cycloidal gear, and the circle centers of the three through holes are respectively spaced by 120 °.

In certain embodiments, the cycloidal gear transmission assembly further comprises a needle bearing disposed between the cycloidal gear and the crank shaft.

The speed reducer comprises the cycloidal gear transmission assembly and the planetary gear transmission assembly according to any one of the above embodiments, wherein the planetary gear transmission assembly comprises a sun gear and a planetary gear, the sun gear is connected with an output shaft of a motor, the sun gear is meshed with the planetary gear for transmission, and the planetary gear is connected with the crankshaft for transmission.

In some embodiments, the speed reducer further comprises a limiting assembly, wherein the limiting assembly is arranged on the crankshaft and abuts against the planet wheel so as to limit the planet wheel to move along the axis direction of the crankshaft.

An industrial robot according to an embodiment of the present utility model includes the speed reducer according to any one of the above embodiments.

According to the speed reducer and the industrial robot, the ratio of the distance from the axis of the flange to the axis of the shaft body to the radius of the needle teeth is limited to be 0.46-0.49, so that the output torque of the transmission assembly can be improved, and the speed reducer is guaranteed to have better shock resistance. Meanwhile, the contact stress between the cycloidal gear and the pin gear is smaller, so that the speed reducer has longer service life.

Additional aspects and advantages of the utility model will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the utility model.

Drawings

The foregoing and/or additional aspects and advantages of the present utility model will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, in which:

Fig. 1 is a schematic view of the structure of a cycloidal gear and pin gear according to an embodiment of the present utility model;

fig. 2 is a schematic view of a partial structure of a speed reducer according to an embodiment of the present utility model.

Description of main reference numerals:

The cycloidal gear transmission assembly comprises a cycloidal gear transmission assembly body 10, a pin gear 12, a cycloidal gear 14, a first cycloidal gear 14a, a second cycloidal gear 14b, a crank shaft 16, a through hole 18, a shaft body 20, a flange 22, a first flange 22a, a second flange 22b, pin teeth 24, a pin gear housing 26, a needle bearing 28 and planet gears 30.

Speed reducer-100.

Detailed Description

Embodiments of the present utility model are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary only for explaining the present utility model and are not to be construed as limiting the present utility model.

In the description of the present utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present utility model. In the description of the present utility model, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

In the description of the present utility model, it should be noted that the terms "mounted," "connected," and "coupled" are to be construed broadly, as well as, for example, fixedly coupled, detachably coupled, or integrally coupled, unless otherwise specifically indicated and defined. Either mechanically or electrically. Can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present utility model, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

The disclosure herein provides many different embodiments or examples for implementing different structures of the utility model. To simplify the present disclosure, components and arrangements of specific examples are described herein. They are, of course, merely examples and are not intended to limit the utility model. Furthermore, the present utility model may repeat reference numerals and/or letters in the various examples, which are for the purpose of brevity and clarity, and which do not themselves indicate the relationship between the various embodiments and/or arrangements discussed. In addition, the present utility model provides examples of various specific processes and materials, but one of ordinary skill in the art will recognize the application of other processes and/or the use of other materials.

Referring to fig. 1 and 2, a cycloidal gear transmission assembly 10 according to an embodiment of the present utility model includes a pin gear 12, a cycloidal gear 14, and a crank shaft 16.

The cycloid gear 14 is provided with a through hole 18, the crank shaft 16 comprises a shaft body 20 and a flange 22, the flange 22 protrudes around the circumferential direction of the shaft body 20, 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 gear 12 is meshed with the cycloid gear 14, the pin gear 12 comprises a plurality of cylindrical pins 24, and the value range of 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 pins 24 is [0.46,0.49].

The cycloidal gear transmission assembly 10 limits the ratio of the distance from the axis of the flange 22 to the axis of the shaft body 20 to the radius of the needle teeth 24 to be 0.46-0.49, can improve the output torque of the transmission assembly, simultaneously avoids the interference between the cycloidal gear 14 and the needle tooth shell 26, has small contact stress of parts, and ensures that the cycloidal gear transmission assembly 10 has better shock resistance.

Specifically, the cycloidal gear assembly 10 may be applied to the speed reducer 100, and optionally, the speed reducer 100 may be an RV (rotational Vector) speed reducer, which is a core component of an industrial robot, and has advantages of high accuracy, high rigidity, long life, and the like. The RV speed reducer is composed of a planetary gear transmission assembly and a cycloid gear transmission assembly 10.

The motion transmission path of the RV speed reducer starts from the input shaft and transmits motion and force to the planetary gear through the engagement of the input shaft with the planetary gear, the planetary gear is connected with the crankshaft 16, and the crankshaft 16 will do the same motion as the planetary gear. The cycloid gear 14 is provided with a through hole 18, the cycloid gear 14 is sleeved on a flange 22 of the crankshaft 16 through the through hole 18, and the axis of the flange 22 is a certain distance H from the axis of the shaft body 20, so that the crankshaft 16 drives the cycloid gear 14 to make eccentric motion and mesh with the needle teeth 24, and finally, load and motion are transmitted to an output shaft.

For RV reducers, a large output torque is required. Accordingly, the output torque can be increased by designing the eccentric amount of the cycloid gear transmission assembly 10. The amount of eccentricity, i.e., the distance H between the axis of flange 22 and the axis of shaft 20, is the radius R of pin 24. The greater the ratio of the amount of eccentricity to the radius of the pin 24 (i.e., the value of H/R), the greater the output torque, but when the value of H/R exceeds 0.5, interference of the cycloidal gear 14 and the pin housing 26 results. In the related art, in order to reduce interference between the cycloidal gear 14 and the pin gear 12, the profile of the cycloidal gear 14 needs to be modified, so that the number of teeth involved in the meshing is reduced when the cycloidal gear 14 meshes with the pin gear 12, which results in a reduction in the shock resistance of the cycloidal gear transmission assembly 10, and an excessive contact stress of parts in the reducer, thereby reducing the overall life.

In the cycloidal gear transmission assembly 10 provided by the embodiment of the utility model, 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 teeth 24 is limited to be 0.46-0.49, specifically, the H/R can be 0.46, 0.47, 0.48 or 0.49, or any value in the range [0.46,0.49], and when the H/R is smaller than 0.46, the output torque of the cycloidal gear transmission assembly 10 is small, and the requirement of high-precision equipment such as an RV speed reducer can not be met. When H/R is greater than 0.49, interference between the cycloidal gear 14 and the pin gear housing 26 may result, thereby reducing the shock resistance of the cycloidal gear transmission assembly 10.

In some embodiments, the pin gear housing 26 is annular, the pin teeth 24 are disposed around the inner wall surface of the pin gear housing 26 at equal intervals, the distance between the converging point 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 gear housing 26 is Q, and the value range of the ratio L/Q is [0.6,0.9].

In this way, the contact stress of the tooth surfaces of the cycloid gear 14 can be reduced, and the life of the cycloid gear 14 can be improved.

Specifically, the needle gear housing 26 has a circular ring shape, and the needle gears 24 are disposed around the inner wall surface of the needle gear housing 26 at equal intervals. The cycloid gear 14 is meshed with the pin gear 24, as shown in fig. 2, at each meshing position, the convergence point of the force of the pin gear 24 on the cycloid gear 14 is marked as a point C, the distance between the point C and the circle center O of the cycloid gear 14 is L, the radius of a circle formed by the circle center of the pin gear 24 is Q, and the value range of the ratio L/Q is [0.6,0.9].

For example, the ratio L/Q may be 0.6, 0.7, 0.8, or 0.9, or any value within the range [0.6,0.9 ]. When the ratio L/Q is less than 0.6 or greater than 0.9, the contact stress of the tooth surfaces of the cycloid gear 14 is excessively high, which affects the life of the cycloid gear 14; meanwhile, the ratio L/Q is limited in the range [0.6,0.9] in consideration of the miniaturization requirement of the cycloidal gear transmission assembly 10 and the cooperation with other parts, so that the service life of the cycloidal gear 14 is prolonged.

In some embodiments, the number of teeth engaged by the external teeth of the cycloidal gear 14 as the pin gear 12 rotates in mesh with the cycloidal gear 14 is equal to one eighth of the total number of teeth of the cycloidal gear 14.

In this manner, the cycloidal gear transmission assembly 10 has a high impact resistance.

Specifically, when the tooth gear is meshed with the cycloid gear 14 for rotation, the external tooth portion of the cycloid gear 14 is meshed with the pin teeth 24 of the pin gear 12 for transmission. When the ratio H/R is between 0.46 and 0.49, the number of teeth of the external tooth portion engaged can theoretically reach half of the total number of teeth of the cycloid gear 14, whereas when the ratio H/R is greater than 0.5, the number of teeth of the external tooth portion engaged can reach half of the total number of teeth of the cycloid gear 14.

In the actual machining application, the number of teeth of the external tooth portion of the cycloid gear 14 engaged is equal to one eighth of the total number of teeth of the cycloid gear 14 due to an error in machining assembly. Whereas the number of teeth of the cycloid gear 14, in which the external tooth portion of the cycloid gear 14 is engaged, of which the ratio H/R is greater than 0.5, cannot reach one eighth of the total number of teeth of the cycloid gear 14.

Referring to fig. 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 20 is equal to the distance between the axis of the second flange 22b and the axis of the shaft 20, 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.

In this way, the impact strength of the cycloidal gear transmission assembly 10 can be improved.

Specifically, the distance between the axis of the first flange 22a and the axis of the shaft body 20, and the like. The first cycloid gear 14a is fitted over the first flange 22a and the second cycloid gear 14b is fitted over the second flange 22b at a distance between the axis of the second flange 22b and the axis of the shaft body 20. Therefore, when the crank shaft 16 rotates, the first cycloid gear 14a and the second cycloid gear 14b eccentrically rotate by the same eccentric amount.

In some embodiments, the axis of the first flange 22a is offset from the axis of the shaft 20 by 180 ° from the axis of the second flange 22 b.

In this way, the first cycloid gear 14a and the second cycloid gear 14b are sleeved on the crank shaft 16 with a 180-degree phase difference, so that the shock resistance of the cycloid gear transmission assembly 10 is improved, the radial runout of the crank shaft 16 is reduced, and the safety factor is improved.

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, i.e., both the first cycloid gear 14a and the second cycloid gear 14b have an eccentric amount with respect to the axis of the crank shaft 16 when rotated. Therefore, the crankshaft 16 rotates with an eccentric force.

The eccentric force increases the moment of inertia, which causes radial runout of the crankshaft 16, and the first cycloid gear 14a and the second cycloid gear 14b are sleeved on the crankshaft 16 with 180 ° difference, so that the movement directions of the first cycloid gear 14a and the second cycloid gear 14b are opposite when the crankshaft 16 rotates, which can effectively cause radial runout of the crankshaft 16, and improve the shock resistance of the cycloid gear transmission assembly 10.

In some embodiments, the cycloidal gear transmission assembly 10 includes three crankshafts 16, the cycloidal gears 14 being provided with three through holes 18 to respectively pass through the three crankshafts 16, the three through holes 18 being disposed around the centers of the cycloidal gears 14 and the centers of the three through holes 18 being respectively spaced apart by 120 °.

In this way, the stress on the crank shaft 16, the cycloid gear 14, and the pin gear 12 can be made uniform.

Specifically, the cycloidal gear transmission assembly 10 includes three crankshafts 16, three through holes 18 are disposed around the centers of the cycloidal gears 14 and the centers of the three through holes 18 are spaced apart by 120 ° respectively, and the cycloidal gears 14 are provided with three through holes 18 to pass through the three crankshafts 16 respectively. By the transmission of the three crankshafts 16, the stress on the crankshafts 16, the cycloidal gears 14 and the pin gear 12 can be uniform.

In certain embodiments, the cycloidal gear transmission assembly 10 further comprises a needle bearing 28, the needle bearing 28 being disposed between the cycloidal gear 14 and the crank shaft 16.

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

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 crank shaft 16, and the needle bearing 28 is located between the cycloid gear 14 and the crank shaft 16. The needle bearings 28 are effective to reduce friction as the crankshaft 16 rotates relative to the cycloid gear 14, thereby reducing wear of the cycloid gear 14 and the crankshaft 16.

In summary, in the cycloidal gear transmission assembly 10 according to the embodiment of the present utility model, the ratio of the distance from the axis of the flange 22 to the axis of the shaft body 20 to the radius of the pin 24 is limited to be between 0.46 and 0.49, so that the output torque of the transmission assembly can be increased, and interference between the cycloidal gear 14 and the pin housing 26 is avoided; secondly, the ratio of the distance L between the convergence point of the needle teeth 24 on the cycloid gear 14 and the circle center of the cycloid gear 14 and the radius Q of the circle formed by the inner wall surface of the needle tooth shell 26 is between 0.6 and 0.9, so that the contact stress can be lower, the shock resistance of the cycloid gear transmission assembly 10 is improved, and the service life of the cycloid gear transmission assembly 10 is prolonged. By the above dimensional limitations, the cycloidal gear transmission assembly 10 achieves a degree of reconciliation of output torque rise and reduction in shock resistance.

A speed reducer 100 of an embodiment of the present utility model includes the cycloidal gear transmission assembly 10 and the planetary gear transmission assembly of any 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 with an output shaft of the motor, the sun gear is meshed with the planetary gear 30 for transmission, and the planetary gear 30 is connected with the crankshaft 16 for transmission.

Specifically, the motor output shaft is connected to a sun gear, the number of planetary gears 30 corresponds to the number of crankshafts 16, and in the case of having a plurality of planetary gears 30, the plurality of planetary gears 30 are equally spaced around the sun gear and mesh with the sun gear to form a first-stage reduction gear mechanism. The planetary gear 30 is fixedly connected with the crank shaft 16, the cycloid gear 14 is sleeved on a convex part with a certain eccentric amount on the crank shaft 16, and meanwhile, the cycloid gear 14 is meshed with the pin gear 12 with cylindrical inner teeth, so that a second-stage reduction transmission mechanism is formed. Through the design of two-stage reduction transmission, the reduction transmission with larger difference between the input rotating speed and the output rotating speed is realized.

In some embodiments, the speed reducer 100 further includes a limiting assembly, which is disposed on the crankshaft 16 and abuts against the planet gear to limit the planet gear from moving along the axis direction of the crankshaft 16.

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

In particular, the limiting assembly can prevent the planet from moving along the axis direction of the crankshaft 16, thereby affecting the transmission accuracy of the reducer and even causing the reducer to fail.

An industrial robot according to an embodiment of the present utility model includes the speed reducer 100 according to any one of the above embodiments.

The speed reducer 100 and the industrial robot limit the ratio of the distance from the axis of the flange 22 to the axis of the shaft body 20 to the radius of the needle teeth 24 to be between 0.46 and 0.49, so that the output torque of the transmission assembly can be improved, and the speed reducer is ensured to have better shock resistance. While the contact stress between the cycloidal gear 14 and the pin gear 24 is small so that the reduction gear has a long service life.

The above explanation of the embodiment and advantageous effects of the cycloidal gear transmission assembly 10 is also applicable to the speed reducer 100 and the industrial robot used in the embodiment of the present utility model, and is not developed in detail here to avoid redundancy.

In the description of the present specification, reference is made to the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., meaning that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the utility model. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the present utility model have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the utility model, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the utility model.

Claims (10)

1. The utility model provides a cycloid gear drive assembly, its characterized in that includes needle gear, cycloid gear and crank axle, the through-hole is seted up to the cycloid gear, the crank axle includes axis body and flange, the flange is around the circumference arch of axis body, the axis of axis body with the axis of flange is parallel, the cycloid gear passes through the through-hole cover is established the flange, the needle gear with cycloid gear meshing, the needle gear includes cylindric a plurality of needle teeth, the axis of flange extremely the distance between the axis of axis body is H, the radius of needle tooth is R, wherein the value range of H/R is [0.46,0.49].

2. The cycloidal gear transmission according to claim 1, wherein the pin gear housing is formed in a circular ring shape, the pin teeth are disposed around an inner wall surface of the pin gear housing at equal intervals, a distance between a converging point of the force of the pin teeth to the cycloidal gear on the cycloidal gear and a center of the cycloidal gear is L at a position where the pin gear is engaged with the cycloidal gear, a radius of a circle formed by the center of the pin gear is Q, and a value range of L/Q is [0.6,0.9].

3. The cycloidal gear transmission according to claim 1 wherein the number of teeth of the cycloidal gear engaged with the external tooth portion of the cycloidal gear when the pin gear is engaged with the cycloidal gear to rotate is equal to one eighth of the total number of teeth of the cycloidal gear.

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

5. The cycloidal gear transmission assembly according to claim 4 wherein the direction of the axis of the first flange deviating from the axis of the shaft differs from the direction of the axis of the second flange deviating from the axis of the shaft by 180 °.

6. The cycloidal gear transmission assembly according to claim 1, characterized in that the cycloidal gear transmission assembly comprises three crankshafts, the cycloidal gear is provided with three through holes to be respectively penetrated through the three crankshafts, the three through holes are arranged around the circle centers of the cycloidal gear and the circle centers of the three through holes are respectively spaced by 120 °.

7. The cycloidal gear transmission assembly according to claim 1 further comprising needle bearings disposed between said cycloidal gears and said crank shaft.

8. A speed reducer, characterized by comprising the cycloidal gear transmission assembly and the planetary gear transmission assembly according to any one of claims 1-7, wherein the planetary gear transmission assembly comprises a sun gear and a planetary gear, the sun gear is connected with an output shaft of a motor, the sun gear is meshed with the planetary gear for transmission, and the planetary gear is connected with a crankshaft for transmission.

9. The speed reducer of claim 8, further comprising a stop assembly disposed on the crankshaft and abutting the planet to limit movement of the planet in the direction of the crankshaft axis.

10. An industrial robot comprising the speed reducer according to claim 8 or 9.