CN117432755A - Planetary gear, transmission mechanism and power device - Google Patents

Abstract

The application relates to a planetary gear, a transmission mechanism and a power device. The planetary gear comprises a first gear part and a second gear part, and the second gear part and the first gear part are axially distributed. The gear parameters of the first gear part and the second gear part comprise the same numerical value parameters and different numerical value parameters, and the same numerical value parameters comprise the number of teeth and the modulus. The planetary gear reduces the design difficulty, improves the performance of the planetary gear train, considers the manufacturing cost and the design difficulty of the NGWN planetary gear train, has convenient process implementation and low manufacturing cost, and widens the application and popularization of the NGWN planetary gear train.

Description

Planetary gear, transmission mechanism and power device

Technical Field

The application relates to the technical field of transmission, in particular to a planetary gear, a transmission mechanism and a power device.

Background

The planetary gear transmission has the capability of power and torque split because a plurality of planetary gears are meshed with the sun gear, and has the characteristics of small volume, light weight, compact structure, high transmission efficiency and the like compared with the common gear transmission.

In planetary gear transmission, the NGWN planetary gear transmission mechanism (hereinafter referred to as NGWN planetary gear train) has the advantages of large transmission ratio, short transmission chain, less number of components, high reliability, capability of realizing reverse self-locking under certain conditions, and the like. However, the manufacturing cost and the design difficulty of the NGWN type planetary gear train are difficult to balance, and the application and popularization of the NGWN type planetary gear train are limited.

Disclosure of Invention

In view of this, it is necessary to provide a planetary gear, a transmission mechanism, and a power unit, which solve the problem that the manufacturing cost and the design difficulty of the NGWN planetary gear train cannot be compatible.

A planetary gear comprising:

a first gear portion; and

the second gear part and the first gear part are axially distributed;

the gear parameters of the first gear part and the second gear part comprise the same numerical value parameters and different numerical value parameters, and the same numerical value parameters comprise the number of teeth and the modulus.

In one embodiment, the numerical variation parameter includes one or more of a displacement coefficient, a tooth top coefficient, and a tooth top circle diameter.

In one embodiment, the numerical value differential parameter includes a shift coefficient, the shift coefficient of the first gear portion being greater than the shift coefficient of the second gear portion.

In one embodiment, the numerical value differential parameter includes a tooth top coefficient, the tooth top coefficient of the first gear portion being greater than the tooth top coefficient of the second gear portion.

In one embodiment, the numerical variation parameter includes a tip circle diameter, and the tip circle diameter of the first gear portion is greater than the tip circle diameter of the second gear portion.

In one embodiment, the first gear portion and the second gear portion are spur gears.

In one embodiment, the plurality of teeth of the first gear portion are disposed in one-to-one alignment with the plurality of teeth of the second gear portion.

A transmission mechanism comprising: the driving wheel, a plurality of planetary gears, a first gear ring and a second gear ring, wherein the first gear ring is fixedly arranged, the second gear ring is movably arranged, the planetary gears are the planetary gears according to any one of the embodiments, the first gear part is meshed with the driving wheel and the first gear ring, and the second gear part is meshed with the second gear ring.

In one embodiment, the first ring gear has a smaller displacement coefficient than the second ring gear.

In one embodiment, the number of teeth of the first ring gear is greater than the number of teeth of the second ring gear.

A power plant, comprising:

a transmission mechanism, which is the transmission mechanism according to any one of the embodiments above; and

and the power source is connected with the driving wheel of the transmission mechanism.

In one embodiment, the power device is a curtain motor or a tubular motor.

The planetary gear, the transmission mechanism and the power device have the advantages that as the first gear part and the second gear part of the planetary gear have the same numerical parameters, the same numerical parameters comprise the number of teeth and the modulus, and the same modulus can be designed to share the same cutter for processing, so that the production efficiency is improved; the design of the same tooth number can reduce the volume of the planetary gear, reduce the manufacturing cost, realize the application of the gear hobbing machine, have higher production efficiency and high gear precision, and can conveniently use the processing of a whirlwind milling machine for the high-precision gear; meanwhile, the first gear part and the second gear part also have numerical value different parameters, namely, the numerical value different parameters are designed differently except the modulus and the tooth number, and the adjustable parameters, the method and the tools are more, so that the design difficulty is greatly reduced, and the performance of the gear train is improved; therefore, the planetary gear reduces the design difficulty, improves the performance of the gear train, considers the manufacturing cost and the design difficulty of the NGWN planetary gear train, has convenient process implementation and low manufacturing cost, and widens the application and popularization of the NGWN planetary gear train.

Drawings

Fig. 1 is a front view of a power plant in an embodiment of the present application.

Fig. 2 is a right side view of the power plant of fig. 1.

Fig. 3 is a schematic structural view of the transmission mechanism of the power device in fig. 1 in a view.

Fig. 4 is a schematic structural view of the transmission mechanism of the power plant in fig. 1 from another perspective.

Fig. 5 is an exploded view of the transmission of fig. 3.

Fig. 6 is a schematic diagram of the planetary gear of the transmission mechanism in fig. 5.

Fig. 7 is a cross-sectional view of the planetary gear of fig. 6.

Fig. 8 is a front view of the planetary gear of fig. 6.

Fig. 9 is a rear view of the planetary gear of fig. 6.

Fig. 10 is a left side view of the planetary gear of fig. 6.

Reference numerals illustrate:

100-power plant; 110-a power source; 120-transmission mechanism; 130-a driving wheel; 140-planetary gears; 142-a first gear portion; 144-a second gear portion; 150-a first ring gear; 160-a second ring gear; 170-a planet carrier; 172-rotating shaft.

Detailed Description

In order to make the above objects, features and advantages of the present application more comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. This application is, however, susceptible of embodiment in many other forms than those described herein and similar modifications can be made by those skilled in the art without departing from the spirit of the application, and therefore the application is not to be limited to the specific embodiments disclosed below.

In the description of the present application, it should be understood that, if there are terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., these terms refer to the orientation or positional relationship based on the drawings, which are merely for convenience of description and simplification of description, and do not indicate or imply that the apparatus or element referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present application.

Furthermore, the terms "first," "second," and the like, if any, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present application, the terms "plurality" and "a plurality" if any, mean at least two, such as two, three, etc., unless specifically defined otherwise.

In this application, unless explicitly stated and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly. For example, the two parts can be fixedly connected, detachably connected or integrated; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art as the case may be.

In this application, unless expressly stated or limited otherwise, the meaning of a first feature being "on" or "off" a second feature, and the like, is that the first and second features are either in direct contact or in indirect contact through an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

It will be understood that if an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. If an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein, if any, are for descriptive purposes only and do not represent a unique embodiment.

Referring to fig. 1 and 2, an embodiment of a power device 100 provided in the present application includes a power source 110 and a transmission mechanism 120, where the power source 110 is connected to an input portion of the transmission mechanism 120, so that power can be input into the transmission mechanism 120, transmitted in the transmission mechanism 120, and finally output from an output portion of the transmission mechanism 120, so that an input speed of the input portion is different from an output speed of the output portion, and a speed change effect is achieved.

In one embodiment, the power source 110 is a motor, and the driving shaft of the motor may be directly connected to the input portion of the transmission mechanism 120, or indirectly connected to the input portion of the transmission mechanism 120 through a connection structure, so as to transmit the torque output by the motor to the input portion of the transmission mechanism 120. Alternatively, in other embodiments, the power source 110 may be a pump, hydraulic motor, cylinder, or other power device.

In one embodiment, the transmission mechanism 120 is a speed reducing mechanism, specifically, a planetary gear transmission mechanism is adopted, and torque is split through a planetary gear in the planetary gear mechanism to achieve the purpose of speed reduction, that is, the speed of an input part is greater than that of an output part, and the speed reducing effect can reach a transmission ratio of 50-500.

Alternatively, in other embodiments, the transmission 120 may be a speed increasing mechanism, i.e., having an input portion with a speed that is less than the speed of an output portion.

In one embodiment, the power device may be, but is not limited to, a window covering motor or a tubular motor. The curtain motor drives the electric curtain to move back and forth along the track through the positive and negative rotation of the curtain motor, the electric curtain motor also comprises a shell, and the power source 110 and the transmission mechanism 120 are arranged in the shell. The tubular motor generally comprises a stroke part, a motor part (a power source 110) and a speed reduction part (a transmission mechanism 120), wherein the three parts are arranged in a circular tube to work, and the stroke part controls the upper limit and the lower limit of the motor part; the motor part is responsible for motor operation; the speed reducing part adopts planetary speed reduction to reduce the rotating speed of the motor and increase the output torque.

Referring to fig. 3 to 5, in one embodiment, the transmission mechanism 120 includes a driving wheel 130, a plurality of planetary gears 140, a first gear ring 150, and a second gear ring 160, where the first gear ring 150 is fixedly disposed, and the second gear ring 160 is movably disposed. The driving wheel 130 serves as an input portion, whose shaft hole is tightly fitted with a driving shaft of the motor, and inputs power. Each of the planetary gears 140 meshes with the driving wheel 130, the first ring gear 150, and the second ring gear 160 as an output portion outputs the transmitted power last. When the motor is operated, the driving shaft of the motor drives the driving wheel 130 to rotate and drives the plurality of planetary gears 140 to rotate, and the plurality of planetary gears 140 simultaneously rotate along the first gear ring 150 to revolve, thereby dividing the input power and torque, and each planetary gear 140 transfers the divided power and torque to the second gear ring 160 through rotation, thereby decelerating the second gear ring 160 to rotate and outputting power.

In one embodiment, the transmission 120 further includes a planet carrier 170, and each planet gear 140 is coupled to the planet carrier 170 by a shaft 172. The shaft hole of the planetary gear 140 is in clearance fit with the rotating shaft 172, or a bearing is added, or a part similar to the bearing is adopted, so that the planetary gear 140 can rotate around the rotating shaft 172. The rotating shaft 172 and the planet carrier 170 are fixed on the planet carrier 170 by adopting interference fit or other fixing modes, so that the planet carrier 170 can rotate around the axis of the planet carrier 170, and meanwhile, the planet carrier 170 can restrain the plurality of planet gears 140 through the rotating shaft 172. It should be noted that, in other embodiments, the transmission mechanism 120 may be a carrier-free planetary system, that is, a support gear is used instead of the planet carrier 170, and the support gear is meshed with the plurality of planet gears 140, and is supported between the planet gears 140, so that the axial length of the planetary system is reduced, and the planetary system mechanism is more compact without assembling the planet carrier 170 and the planet gears.

Further, the driving wheel 130 is a sun gear. The first ring gear 150 is fixed against movement by screws or the like. The second ring gear 160 may rotate about its own axis with a bearing or the like as an output portion, and eventually, the power output of the planetary gear train is subjected to work.

In one embodiment, the plurality of planetary gears 140 may be, but are not limited to, four planetary gears 140, and four shafts 172 are in one-to-one correspondence with the four planetary gears 140, and each shaft 172 may be, but is not limited to, a pin. Alternatively, in other embodiments, the number of the planetary gears 140 may be two, three, five or more, and the number of the rotating shafts 172 may be set corresponding to the number of the planetary gears 140, as the case may be.

Referring to fig. 6 and 7, in one embodiment, the planetary gear 140 includes a first gear portion 142 and a second gear portion 144, and the second gear portion 144 and the first gear portion 142 are axially distributed. Referring to fig. 5, the first gear portion 142 is engaged with the first ring gear 150, and is engaged with the drive wheel 130, and the second gear portion 144 is engaged with the second ring gear 160. The term "axial direction" is generally used for a cylindrical object, and is a direction along the central axis of rotation of the cylinder, i.e., a direction common to the central axis. The "radial direction" is perpendicular to the "axial direction", i.e. the radial or diametrical direction of the cylinder end face circle.

In one embodiment, the planetary gear 140 may be, but is not limited to, a double planetary gear, which refers to only a first gear portion 142 and a second gear portion 144, and no other gear portions. Obviously, in other embodiments, the planetary gear 140 may further include a third gear portion and even a fourth gear portion according to actual requirements based on the first gear portion 142 and the second gear portion 144.

In one embodiment, the first gear portion 142 and the second gear portion 144 are axially spaced apart to accommodate the spacing distance between the first ring gear 150 and the second ring gear 160. Alternatively, in other embodiments, the first gear portion 142 and the second gear portion 144 may be axially coupled without a gap.

In one embodiment, the transmission 120 is an NGWN type planetary gear transmission (hereinafter abbreviated as an NGWN type planetary gear train), and in the classification of planetary gear transmissions, the planetary gear transmissions may be classified into gear engagement according to related books and other information of mechanical design: NGW type, NW type, NN type, WW type, NGWN type, N type, and the like. Wherein, the meaning of the letters is interpreted as: n-internal engagement, W-external engagement and G-common planetary gear set. Obviously, the NGWN planetary gear train has 2 ring gear pairs (N), 1 ring gear pair (W) and 1 common planetary gear set (G). It should be noted that, in the present application, the transmission mechanism 120 is not limited to the NGWN planetary gear train, but may be another planetary gear train.

The NGWN planetary gear train has the advantages of compact structure, large transmission ratio, high efficiency, small volume and the like, and can effectively meet the engineering technical requirements of large load and small volume. However, the conventional NGWN planetary gear train cannot achieve both manufacturing cost and design difficulty.

In order to balance the manufacturing cost and the design difficulty of the NGWN planetary gear train, the planetary gear 140 adopts a new design, wherein the gear parameters of the first gear portion 142 and the second gear portion 144 comprise the same numerical parameter and the different numerical parameter, and the same numerical parameter comprises the number of teeth and the modulus, that is, the number of teeth and the modulus of the first gear portion 142 and the second gear portion 144 are the same. It should be noted that all gear parameters include two parts: the same parameter and the different parameter are the rest parameters except the same parameter, wherein the same parameter comprises two kinds of parameters: number of teeth and modulus. In other words, the number of teeth and the modulus of the first gear portion 142 and the second gear portion 144 are the same, while the remaining gear parameters of both are different. Since the gear parameters are limited and the same parameters are determined, the numerical parameters can be obtained by the elimination method, and therefore, the numerical parameters are limited and can be enumerated.

Because the first gear part 142 and the second gear part 144 have the same numerical parameters, the same numerical parameters comprise the number of teeth and the modulus, and the same cutter can be used for processing by the same modulus, so that the production efficiency is improved; the design of the same tooth number can reduce the volume of the planetary gear, reduce the manufacturing cost, realize the application of the gear hobbing machine, have higher production efficiency and high gear precision, and can conveniently use the processing of a whirlwind milling machine for the high-precision gear; meanwhile, the first gear part 142 and the second gear part 144 also have numerical value different parameters, namely, the numerical value different parameters are designed differently except for the modulus and the number of teeth, and the adjustable parameters, the method and the tools are more, so that the design difficulty is greatly reduced, the performance of the gear train is improved, therefore, the newly designed planetary gear 140 can be matched with the first gear ring 150 and the second gear ring 160, the design difficulty is reduced, the performance of the gear train is improved, the manufacturing cost and the design difficulty of the NGWN type planetary gear train are considered, the process is convenient to realize, the manufacturing cost is low, and the application and popularization of the NGWN type planetary gear train are widened.

In one embodiment, the numerical value of the different parameters includes one or more of a deflection coefficient, a tooth top coefficient and a tooth top circle diameter, and the gear parameters are particularly important for the performance and processing of the gear on the basis of determining the tooth number and the modulus, so that the gear processing and the improvement of the gear performance can be facilitated by controlling the gear parameters.

In one embodiment, the planetary gear 140 is a shift gear, wherein the numerical variation parameter includes a shift coefficient, and the shift coefficient of the first gear portion 142 is greater than the shift coefficient of the second gear portion 144. According to the displacement amount (mm) =x×m, where x is a displacement coefficient and m is a modulus, since the modulus of the first gear portion 142 is equal to the modulus of the second gear portion 144, the displacement amount of the first gear portion 142 is greater than the displacement amount of the second gear portion 144, so that the first gear portion 142 has higher strength and service life, lower meshing noise, and better load distribution, and the first gear portion 142 can better mesh with the driving wheel 130, thereby meeting the requirements of power and torque split.

Further, the numerical value different parameters further include a tooth top coefficient, the tooth top coefficient of the first gear portion 142 is greater than the tooth top coefficient of the second gear portion 144, and according to the tooth top coefficient ha=ha/m, ha is the tooth top, m is the modulus, since the modulus of the first gear portion 142 is equal to the modulus of the second gear portion 144, it is obvious that the tooth top of the first gear portion 142 is greater than the tooth top of the second gear portion 144, when the first gear portion 142 is meshed with the first gear ring 150, interference can be avoided, transmission efficiency is improved, and the increase of the tooth top can increase the working contact area of the gears, reduce the load of a single tooth, thereby improving transmission efficiency and transmission capacity to better maintain the deceleration effect.

Referring to fig. 8 to 10, in one embodiment, the numerical parameters further include a top circle diameter, da1, of the first gear portion 142 is larger than a top circle diameter, da2, of the second gear portion 144, and it is apparent that the bearing capacity, transmission accuracy, working reliability and service life of the first gear portion 142 are better, so as to be beneficial to splitting power and torque.

In one embodiment, and in conjunction with fig. 5, to accommodate the corresponding designs of the first gear portion 142 and the second gear portion 144, the displacement coefficient of the first ring gear 150 is smaller than the displacement coefficient of the second ring gear 160, which is beneficial for improving the gear ratio.

Further, the number of teeth of the first ring gear 150 is greater than the number of teeth of the second ring gear 160, so that the planetary gear train has a higher gear ratio.

In one embodiment, the first gear portion 142 and the second gear portion 144 are spur gears, which are less difficult to design and process and more stable in performance. Alternatively, in other embodiments, at least one of the first gear portion 142 and the second gear portion 144 may be a helical gear.

In one embodiment, the plurality of teeth of the first gear portion 142 and the plurality of teeth of the second gear portion 144 are aligned one by one, which is beneficial to reducing design and processing difficulty and saving manufacturing cost. Alternatively, in other embodiments, the plurality of teeth of the first gear portion 142 may be offset from the plurality of teeth of the second gear portion 144.

In one embodiment, the planetary gear 140 is of unitary construction. Alternatively, in other embodiments, the planetary gear 140 may be a split structure, where the first gear portion 142 and the second gear portion 144 may be processed independently, and then the two gear portions are welded or connected by a fastener, so as to reduce the processing difficulty of the planetary gear 140 and improve the production efficiency.

In one embodiment, the drive wheel 130: the number of teeth was 18, and the displacement coefficient was 0.7. First gear portion 142: the number of teeth is 33, and the deflection coefficient is 0.8665; first ring gear 150: the number of teeth is 87, the deflection coefficient is 0.1675, and the center distance is 26.2mm. Second gear portion 144: the number of teeth is 33, and the deflection coefficient is 0.0665; second ring gear 160: the number of teeth is 84, the deflection coefficient is 0.8329, and the center distance is 26.2mm. The first gear portion 142 and the second gear portion 144 have the same modulus, the modulus may be set according to the actual requirement, and the modulus of the first gear ring 150 and the second gear ring may be set according to the actual situation. It should be noted that the gear parameters of the above components are exemplary and not limiting, and based on the inventive concept of the present application, the actual values of the gear parameters of the above components may be flexibly adjusted in combination with practical applications.

Referring to fig. 2 to 5, the operating principle of the transmission mechanism 120 is as follows:

firstly, a motor is started to transmit power to a driving wheel 130 of the NGWN planetary gear train, the driving wheel 130 is meshed with a first gear part 142 of a planetary gear 140, and the power is transmitted to a second gear part 144 of the planetary gear 140;

secondly, the planetary gear 140 is engaged with the first ring gear 150 through the first gear part 142, and the first ring gear 150 is fixed so as not to move, and revolves along the first ring gear 150, and on the other hand, transmits power to the rotation shaft 172, thereby rotating the planet carrier 170;

finally, the second gear portion 144 of the planetary gear 140 meshes with the second ring gear 160, transmitting power to the second ring gear 160, and the second ring gear 160 ultimately transmits power out of the NGWN planetary gear train, achieving a high reduction gear ratio variation of 50-500.

In summary, in the present application, the first gear portion 142 and the second gear portion 144 of the planetary gear 140 have both the same numerical parameters and different numerical parameters, and simultaneously have two problems of manufacturing cost and design difficulty; the numerical value same parameter comprises a modulus and the number of teeth, and the design of the same modulus can share the same cutter for processing, so that the production efficiency is improved; the design of the same tooth number can reduce the volume of the planetary gear, reduce the manufacturing cost, realize the application of the gear hobbing machine, have higher production efficiency and high gear precision, and can conveniently use the processing of a whirlwind milling machine for the high-precision gear; besides modulus and tooth number, the numerical value different parameters are designed differently, the adjustable parameters, methods and tools are more, the design difficulty is greatly reduced, and the performance of the gear train is improved, so that the newly designed planetary gear 140 can be matched with the first gear ring 150 and the second gear ring 160, the design difficulty is reduced, the performance of the gear train is improved, the manufacturing cost and the design difficulty of the NGWN planetary gear train are considered, the process is convenient to realize, the manufacturing cost is low, and the application and popularization of the NGWN planetary gear train are widened. It should be noted that, in the present application, the application of the planetary gear 140 is not limited to the NGWN planetary gear train, and may be applied to other suitable transmission mechanisms.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples only represent a few embodiments of the present application, which are described in more detail and are not to be construed as limiting the scope of the claims. It should be noted that it would be apparent to those skilled in the art that various modifications and improvements could be made without departing from the spirit of the present application, which would be within the scope of the present application. Accordingly, the scope of protection of the present application is to be determined by the claims appended hereto.

Claims (12)

1. A planetary gear, comprising:

a first gear portion; and

the second gear part and the first gear part are axially distributed;

the gear parameters of the first gear part and the second gear part comprise the same numerical value parameters and different numerical value parameters, and the same numerical value parameters comprise the number of teeth and the modulus.

2. The planetary gear according to claim 1, wherein the numerical variation parameter includes one or more of a shift coefficient, a tooth top coefficient, and a tooth top circle diameter.

3. The planetary gear according to claim 1 or 2, wherein the numerical variation parameter includes a shift coefficient, the shift coefficient of the first gear portion being larger than the shift coefficient of the second gear portion.

4. The planetary gear according to claim 1 or 2, wherein the numerical variation parameter includes a tooth top coefficient, the tooth top coefficient of the first gear portion being larger than the tooth top coefficient of the second gear portion.

5. The planetary gear according to claim 1 or 2, wherein the numerical variation parameter includes a addendum circle diameter, and the addendum circle diameter of the first gear portion is larger than the addendum circle diameter of the second gear portion.

6. The planetary gear according to claim 1 or 2, wherein the first gear portion and the second gear portion are spur gears.

7. The planetary gear according to claim 1 or 2, wherein the plurality of teeth of the first gear portion are disposed in one-to-one alignment with the plurality of teeth of the second gear portion.

8. A transmission mechanism comprising: the planetary gear set comprises a driving wheel, a plurality of planetary gears, a first gear ring and a second gear ring, wherein the first gear ring is fixedly arranged, and the second gear ring is movably arranged, and is characterized in that the planetary gears are any one of the planetary gears in claims 1 to 7, the first gear part is meshed with the driving wheel and the first gear ring, and the second gear part is meshed with the second gear ring.

9. The transmission of claim 8, wherein the first ring gear has a coefficient of deflection that is less than the coefficient of deflection of the second ring gear.

10. A transmission according to claim 8 or 9, wherein the number of teeth of the first ring gear is greater than the number of teeth of the second ring gear.

11. A power plant, comprising:

a transmission mechanism according to any one of claims 8 to 10; and

and the power source is connected with the driving wheel of the transmission mechanism.

12. The power plant of claim 11, wherein the power plant is a curtain motor or a tubular motor.