CN116677749A

CN116677749A - Involute few-tooth-difference planetary gear reducer with belt wheel output and speed reducing method thereof

Info

Publication number: CN116677749A
Application number: CN202310805089.8A
Authority: CN
Inventors: 张宏林
Original assignee: Xian Siyuan University
Current assignee: Xian Siyuan University
Priority date: 2023-07-03
Filing date: 2023-07-03
Publication date: 2023-09-01

Abstract

The application provides an involute few-tooth-difference planetary gear reducer with belt wheel output and a speed reducing method thereof, and belongs to the technical field of speed reducers. Because the planetary gear is limited by the eccentric element, the planetary gear can only revolve and rotate within the range of 3mm radius, at the moment, the gear ring rotates in the same direction for 2 teeth to obtain speed reduction, and then the low-speed rotation motion of the gear ring is transmitted to the belt wheel by virtue of the belt wheel fixedly connected with the gear ring, so that lower output rotating speed is obtained.

Description

Involute few-tooth-difference planetary gear reducer with belt wheel output and speed reducing method thereof

Technical Field

The application relates to the technical field of reducers, in particular to an involute small tooth difference planetary gear reducer with belt wheel output and a speed reducing method thereof.

Background

In industrial and agricultural production, the speed reducer is widely applied. Speed reducers are very much paid attention to in academia as important mechanical transmission devices in manufacturing industry, and are increasingly developed towards high precision, miniaturization, low cost, high standard, high bearing and high reliability. The types of commonly used speed reducers are worm gear speed reducers, cycloidal pin gear speed reducers, cylindrical gear speed reducers, planetary gear speed reducers and the like, wherein the precision transmission devices widely applied in the field of mechanical industry are RV speed reducers, planetary speed reducers, spinea speed reducers, harmonic speed reducers and the like.

The worm gear and worm reducer can transmit deceleration and large torque, but has the defects of complex manufacturing process and high cost due to low power. The harmonic transmission realizes the transmission of motion and power by utilizing the elastic deformation of the thin-wall part, has the advantages of light weight, high transmission precision, multiple meshing teeth numbers and the like, but has the trend of being replaced by precise cycloid transmission due to the short service life and low torsional rigidity of the harmonic transmission. The RV reducer is a closed planetary transmission mechanism taking involute planetary and cycloid pin gear small tooth difference planetary two-stage reduction transmission as a main structure, has the advantages of large reduction ratio, high bearing capacity, high torsional rigidity, high efficiency, low vibration, small volume and the like, but also has the problems of large needle pendulum meshing angle, low reliability of a rotating arm bearing, high requirements on the position degree of pin teeth and difficult installation. The traditional straight-tooth cylinder involute speed reducer has the following main defects in the actual use process: firstly, the number of meshing teeth is small, and the bearing capacity is low (determined by the meshing coincidence of gears); secondly, when the transmission load is larger, the gear teeth can generate larger elastic deformation, so that the whole machine is not stable in transmission and high in noise; thirdly, the overall structure has larger external dimension and volume and is difficult to shrink. The application improves the problems existing in the traditional straight tooth cylinder involute speed reducer.

Disclosure of Invention

The application aims at providing an involute small tooth difference planetary gear reducer with pulley output and a speed reducing method thereof, aiming at the requirements in the prior art, wherein the transmission device can be divided into three parts: an input part, a deceleration part and an output part. The input shaft is provided with 2 eccentric 180-degree crank (eccentric wheel) with 3mm eccentric, 2 eccentric sleeves with 180-degree eccentric are arranged on the crank of the input shaft, and two roller bearings called rotating arms are arranged on the eccentric sleeves to form an H mechanism (rotating arms). The central holes of the two planetary gears are the roller paths of the rotating arm bearing on the eccentric sleeve, and the planetary gears are meshed with the gear ring to form an internal meshing speed reducing mechanism with the tooth difference of 2 teeth.

The application adopts the technical scheme that:

it is an object of the present application to provide an involute small tooth difference planetary gear reducer with pulley output, which includes a planetary gear, a ring gear, an eccentric member, and an output mechanism located on the planetary gear and fixedly connected to a housing, the planetary gear being disposed on the eccentric member and meshed with the ring gear, the torque and motion being output through the ring gear output.

In the technical scheme, the eccentric element comprises an eccentric shaft, 2 crank throws which are staggered by 180 degrees and have the eccentricity of 3mm are arranged on the eccentric shaft, and the input end of the eccentric shaft is connected with the elastic pin coupler.

In the above technical solution, further, the planetary gear includes a first planetary gear and a second planetary gear, and two rocking arm bearings of the first planetary gear and the second planetary gear are respectively disposed on 2 cranks.

In the above technical solution, further, the number of teeth of the ring gear is 43, the number of teeth of the first planetary gear and the second planetary gear is 41, and the transmission ratio is 21.5.

In the above technical scheme, further, output mechanism includes round pin axle and round pin axle cover, the round pin axle is provided with 6, and 6 round pins all set up in the cylinder hole of mutually supporting on first planet wheel and the second planet wheel, the round pin axle cover is established in the outside of round pin axle.

In the above technical scheme, further, the casing is fixed on the base, the casing includes left support arm and right support arm, the stack shell of left support arm and right support arm passes through first bearing and second bearing to be set up on the eccentric shaft, peg graft respectively on the end wall of the upper stack shell of left support arm and right support arm at the both ends of round pin axle.

In the above technical scheme, further, the outer ends of the first bearing and the second bearing are respectively provided with a first bearing cover, and the first bearing covers are sleeved on the eccentric shaft and are connected with the end wall of the upper barrel body of the left support arm/the right support arm through bolts.

In the above technical scheme, further, the gear ring is located between the left support arm and the right support arm and fixedly connected with the belt wheel, and the belt wheel bearings are arranged between the belt wheel and the outer walls of the left support arm and the right support arm.

In the above technical scheme, further, the outer walls of the left support arm and the right support arm are respectively provided with a second bearing cover, and the second bearing covers are connected with the side wall of the belt wheel through bolts to realize sealing on the belt wheel bearing.

Another object of the present application is to provide a deceleration method of an involute small tooth difference planetary gear reducer with pulley output, characterized in that the deceleration method includes:

the motor inputs power through the elastic pin coupling, the eccentric shaft rotates along with the elastic pin coupling, 2 eccentric crank shafts which are staggered by 180 degrees and eccentric by 3mm are arranged on the eccentric shaft, the crank shafts on the eccentric shaft rotate corresponding to a sun gear, the planetary gears revolve around the axis of the eccentric shaft, the planetary gears revolve while being meshed with a gear ring, the planetary gears revolve while being necessarily rotated, 6 pin shafts are fixed on a frame, 6 pin shaft sleeves are arranged on the pin shafts and can rotate, the double-sided gap between the pin shaft sleeves and the planetary gears is exactly 3mm, so that the planetary gears can maintain revolution, but rotation is limited, rotation and revolution of the planetary gears are simultaneously carried out, the rotation of the gear ring output and the rotation after the speed reduction of the eccentric gears are in the same direction, and the rotation speed is the product of the gear number of the gear ring minus the ratio of the number of the tooth number of the planetary gears to the number of the gear ring gear and then and the rotation speed of the input shaft.

The application has the beneficial effects that:

the application relates to an involute planetary gear reducer with small tooth difference and output by a belt wheel, wherein an input shaft is provided with 2 eccentric 180-degree offset crank wheels (eccentric wheels) with 3mm eccentric, the crank wheels of the input shaft are provided with 2 eccentric sleeves with 180-degree offset, the eccentric sleeves are provided with two roller bearings called rotating arms, and when the input shaft rotates for one circle with the eccentric sleeves, the planetary wheels are meshed with a gear ring, and the movement of the planetary wheels becomes planar movement with revolution and rotation. When the input shaft rotates forward for 1 week, the eccentric sleeve also rotates for 1 week. The planetary gear is limited by the pin shaft and can only revolve and rotate within the range of 3mm radius, at the moment, the gear ring rotates by 2 teeth in the same direction to obtain speed reduction, and then the low-speed rotation motion of the gear ring is transmitted to the belt wheel by virtue of the belt wheel fixedly connected with the gear ring, so that lower output rotating speed is obtained.

1. High speed ratio and high efficiency: the single-stage transmission can achieve the reduction ratio of 1:21.5, and the transmission efficiency is higher.

2. Compact structure and small volume: because the planetary transmission principle is adopted, the input shaft and the output shaft are on the same axis, so that the machine type of the machine is as small as possible.

3. Smooth operation noise is low: the involute teeth with small tooth difference have more tooth numbers, large overlap coefficient and mechanism of machine element balance (2 eccentric wheels with 180 degrees of dislocation), so that the vibration and noise are limited to the minimum.

4. The pin shaft type W mechanism (output mechanism) is a main form of the output mechanism in the small tooth difference planetary reducer. In a common pin shaft type W mechanism (output mechanism), the pin shafts are arranged in a cantilever manner, and the weak links on the strength of the speed reducer are often caused by poor stress conditions. The design adopts the gear ring for output, and the pin shaft of the W mechanism (output mechanism) is fixed and simple, so the stress condition is good.

5. The actual measurement result shows that the total mechanical efficiency of the planetary reducer with small tooth difference is about 0.73-0.91. The power loss is large during continuous operation, and the defects of overheating of the machine body and the like can be caused, so that the machine is generally suitable for occasions with light load and short-time work. The reason for this condition is the inefficiency of the output mechanism, which is the most significant reason for the overall inefficiency of the low differential gear transmission. The design does not adopt the pin shaft output of the W mechanism, so that the transmission efficiency can be greatly improved.

Drawings

In order to more clearly illustrate the embodiments of the application or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic diagram of the movement of the involute few-tooth-difference planetary reducer mechanism in this embodiment.

Fig. 2 is an external view of the involute few-tooth-difference planetary reducer mechanism in the present embodiment.

Fig. 3 is a cross-sectional view of the involute few-tooth-difference planetary reducer mechanism in this embodiment.

Fig. 4 is an external view of the connection of the eccentric shaft with the planetary gear and the ring gear in the present embodiment.

Fig. 5 is a front cross-sectional view of fig. 4.

Fig. 6 shows the meshing condition of the involute few-tooth-difference planetary reducer in the present embodiment.

1, a base; 2. a housing; 3. sealing the felt; 4. an elastic pin coupling; 5. a pulley bearing; 6. a belt wheel; 7. a gear ring; 8. a swivel arm bearing; 9. a snap ring for holes; 10. a pin sleeve; 11. a pin shaft; 12. a first bearing cap; 13. a hand wheel; 14. a framework oil seal; 15. a flat key; 16. an eccentric shaft; 17. a first bearing; 18. a second bearing; 19. a second bearing cover; 20. a first planet; 21. and a second planet wheel.

A-outputting a gear ring; b-planet wheels; c-input shaft (eccentric, planet carrier); 4. a planet wheel; 5.W mechanism.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application.

The embodiment provides an involute small tooth difference planetary gear reducer with a belt wheel output, the mechanism diagram of the planetary gear reducer is shown in fig. 1, an input shaft A rotates, and 2 crank throws which are staggered by 180 degrees on the input shaft A drive planetary gears B, D to rotate respectively. The W mechanism is provided with 6 pin shafts 11 which are uniformly distributed and respectively inserted into cylindrical holes of the planet gears B, D, so that the planet gears B, D can rotate but revolve around the rotation angleThe range of degrees is limited. The ring gear 7 simultaneously transfers the rotation of the planet B, D into the output ring gear 7A, forcing the output ring gear 7A to rotate. When the input shaft rotates for 1 turn, the gear ring 7 rotates for z ₂ -z ₁ =2 teeth, effecting deceleration. The design of 2 eccentric wheels and planetary wheels is to make the load evenly distributed during engagement, to reduce the load and to balance dynamically.

FIG. 1 shows involute few tooth differences (z ₂ -z ₁ The basic components of the K-H-V planetary transmission are a fixed central wheel b (code number K), a rotating arm H and an output component V). The W mechanism is fixedly connected with the frame, the planetary external gear is driven by the eccentric element (planet carrier) to be meshed with the annular gear 7, and torque and motion are output through the output of the annular gear 7, so that the work of production resistance is overcome.

The eccentric wheel is a rotating arm, in the planetary gear transmission with small tooth difference, the supporting planetary gear is an eccentric component, and the center distance between the planetary gear and the central gear (the annular gear 7) is the eccentric value of the eccentric element, namely e=3 mm. The modulus of the corresponding planet gear and sun gear (ring gear 7) takes m=3.

As shown in fig. 2 to 5, the speed reducer includes a planetary gear, a ring gear 7, an eccentric member, and an output mechanism that is located on the planetary gear and is fixedly connected to the housing 2, the planetary gear being provided on the eccentric member and engaged with the ring gear 7, and outputs torque and motion through the ring gear 7.

Specifically, the eccentric element comprises an eccentric shaft 16, 2 crank throws which are staggered by 180 degrees and have an eccentricity of 3mm are arranged on the eccentric shaft 16, the input end of the eccentric shaft 16 is connected with a flat key 15 of the elastic pin coupler 4, and the other end of the eccentric shaft is connected with a flat key 15 of the hand wheel 13. The hand wheel 13 may not be assembled when in use. When the power is off, the vehicle can be installed and used when the vehicle needs to be turned off. The shaft coupling in the figure can also be selected from other types of shaft couplings. The belt pulley in the figure can also be changed into a mechanical winch for lifting the weight. These are all accessories of the involute planetary reducer with small tooth difference and can be flexibly replaced. The speed reducer can be matched with three asynchronous motors, a stepping motor and a pneumatic motor for reinforcement. Can also be matched with a transfer case of an internal combustion engine for use

The planetary gear comprises a first planetary gear 20 and a second planetary gear 21, wherein two arm bearings 8 (model NJ 207E) of the first planetary gear 20 and the second planetary gear 21 are respectively arranged on 2 cranks. The number of teeth of the gear ring 7 is 43, the number of teeth of the first planetary gear 20 and the second planetary gear 21 is 41, and the transmission ratio is 21.5.

The output mechanism comprises pin shafts 11 and pin shaft 11 sleeves 10, 6 pin shafts 11 are arranged in cylindrical holes on the first planet gears 20 and the second planet gears 21, and the pin shaft 11 sleeves 10 are sleeved on the outer sides of the pin shafts 11.

The shell 2 is fixed on the base, the shell 2 comprises a left supporting arm and a right supporting arm, the barrels of the left supporting arm and the right supporting arm are arranged on the eccentric shaft 16 through a first bearing 17 (model 6205) and a second bearing (model 205E), and two ends of the pin shaft 11 are respectively inserted into end walls of the upper barrels of the left supporting arm and the right supporting arm. The outer ends of the first bearing 17 (model 6205) and the second bearing (model 205E) are respectively provided with a first bearing cover 12, and the first bearing cover 12 is sleeved on the eccentric shaft 16 and is connected with the end wall of the upper barrel body of the left support arm/the right support arm through bolts. And a framework oil seal 14 is arranged between the first bearing cover 12 and the first bearing 17/second bearing.

The gear ring 7 is located between the left support arm and the right support arm and fixedly connected with the belt wheel, and a belt wheel bearing 5 (model 61922) is arranged between the belt wheel and the outer walls of the left support arm and the right support arm. Second bearing covers 19 are arranged on the outer walls of the left support arm and the right support arm, and the second bearing covers 19 are connected with the side walls of the belt wheels through bolts to seal the belt wheel bearings 5. A felt seal 3 is provided between the inner wall of the second bearing cover 19 and the outer wall of the upper barrel of the left/right support arm.

Working principle: the motor inputs power through the elastic pin coupling, the eccentric shaft rotates along with the elastic pin coupling, the crank on the eccentric shaft rotates corresponding to the sun gear, the power is transmitted into the planet gears, and the power is transmitted into the gear ring and drives the belt wheels to rotate due to the fact that the planet carrier is fixed.

In the planetary gear train, which is composed of 4 parts of a sun gear, a planet carrier and a gear ring, if a determined movement form is desired, the movement form of 2 parts needs to be determined. In this scheme, the rotation of the sun gear and the fixation of the planet carrier are determined, so that the only movement mode exists.

The more detailed explanation is:

the motor inputs power through the elastic pin coupling, the eccentric shaft rotates along with the elastic pin coupling, 2 eccentric cranks with 180 degrees dislocation and 3mm eccentricity are arranged on the eccentric shaft 17, 2 rotating arm bearings NJ207E are respectively arranged on the 2 crank cranks, planetary gears 21 are respectively arranged on the 2 rotating arm bearings, the planetary gears 21 and the gear ring 9 have the same modulus 3, and the planetary gears are arranged for internal engagement. The ring gear 9 has 43 teeth, and the planetary gear 21 has 41 teeth, which are meshed with a small difference. The rotation of the bell crank causes the planetary gear 21 to revolve around the axis of the eccentric shaft 17, and there is necessarily a rotation of the planetary gear 21 while revolving due to the engagement with the ring gear 9. However, since 6 pins 13 are fixed on the frame, 6 pin sleeves 12 are mounted on the pins 13 to be hinged and rotatable. The double-sided clearance between the pin bush 12 and the planetary gear 21 is exactly 3mm, so that the planetary gear 21 can maintain revolution, but the rotation is limited. The rotation and revolution of the planetary gear 21 must be performed simultaneously, and since the rotation of the ring gear 9 is not limited, the ring gear 9 outputs rotation in the same direction as the eccentric wheel, but rotation after deceleration, the rotation speed is the product of the number of teeth of the ring gear minus the ratio of the number of teeth of the planetary gear to the number of teeth of the ring gear, and then the rotation speed of the input shaft. And the pulley 8 is integrally fixedly connected with the ring gear 9, so that the pulley outputs a decelerated rotation speed.

Summarizing the transmission process, it can be approximately understood that: the motor inputs power through the elastic pin coupling, the eccentric shaft rotates along with the elastic pin coupling, the planet carrier does not rotate (corresponding to the planet wheel does not self-transfer), and the sun wheel outputs rotation to the gear ring through the planet wheel. The difference here is that the planet wheel is very large, the planet carrier evolves as a pin and the sun wheel evolves as an eccentric shaft.

The sizes of the pin shafts 11 uniformly distributed on the 6 planet gears 20 and 21 are as follows

d ₂ ＝d ₁ +2e (1)

d ₂ Is the inner diameter of the small shaft hole d ₁ The outer diameter of the pin 11 sleeve 10 is e, and e is the crank eccentricity, so that the requirement of rotation of a planet carrier (crank) or the requirement of revolution of a planet wheel is just met. And the rotation of the planet wheel transmits this rotation through engagement with the ring gear 7.

The scheme adopts a K-H-V type (N type) planetary transmission mechanism with small tooth difference, the inner gear ring 7 outputs, and the transmission ratio is as follows:

wherein z is ₂ For tooth number of gear ring 7, z ₂ ＝43，z ₁ For the number of teeth of planet wheel, z ₁ =41, tooth number difference is 2. The gear ratio is positive, indicating that the ring gear 7 is rotating in the same direction as the input shaft (carrier).

Additionally, the inner walls of the first planet wheel 20 and the second planet wheel 21 are provided with hole snap rings 9, and the two hole snap rings 9 are sleeved on the eccentric shaft 16 and positioned on the back surfaces of the two rotating arm bearings 8. The sealing performance of the machine is improved, and the service life is prolonged.

Parameter selection

The number difference of teeth between the internal gear and the planet gear is small, interference phenomenon is easy to generate, in order to avoid interference, a deflection gear is needed, the tooth top coefficient is reduced, design and calculation are complex, and an optimization scheme is not easy to obtain by adopting a trial-and-error method.

The involute planetary reducer with small tooth difference has the advantages of compact structure, small volume, light weight, large transmission ratio, high transmission efficiency and convenient manufacture and maintenance. And thus are increasingly widely used. However, the transmission line type is internally meshed planetary gear transmission, so that the design is complex, and the self-design manufacturers are not hoped to be forcible, thereby seriously affecting popularization and application. In the design of the involute planetary reducer with small tooth difference, the smaller the tooth difference number is, the larger the reduction ratio is, and the more easily the improper design of the inner and outer teeth is interfered; the larger the number of teeth difference, the larger the meshing angle, the smaller the reduction ratio, and the less the internal and external teeth are interfered.

For standard involute ring gear transmission, when the tooth difference between the internal gear b and the external gear a is less than 8, namely z _p ＝z _b -z _a ＜8(z _b 78-200), the ring gear pair will produce tooth profile interference. In order to avoid interference of the ring gear transmission, a shifted ring gear transmission may be employed.

When designing the planetary transmission with small tooth difference, in order to eliminate the tooth profile overlapping interference phenomenon of the internal engaged gear pair, the positive transmission with short tooth system and angle displacement is usually adopted, so that the calculation is relatively complex. After the transmission type and design has been selected, the basic parameters of the planetary transmission need to be selected and the geometric dimensions calculated. Wherein the main parameters influencing the design thereof are

1 teeth number, which should satisfy a given gear ratio

The 2 modulus, the general modulus, should be determined by the strength conditions and the structural dimensions. For the planetary transmission with small tooth difference, the contact strength of the gear teeth and the bending strength of the tooth root are improved due to the adoption of the internal engaged gear pair with larger positive displacement, so that the modulus finally depends on the limitation of the structural size.

3 pressure angle, the standard pressure angle is regulated by China to 20 degrees.

4 addendum coefficient

In the planetary transmission with small tooth difference, the presently adopted tooth top coefficientAs can be seen from the study, the tooth number difference z _p In certain cases, the appropriate decrease +.>The value of the meshing angle a' can be reduced, which is beneficial to eliminating the overlapping interference of tooth profiles and improving the transmission efficiency and the bending strength of the gear teeth.

5. Gear shaping cutter deflection coefficient

In order to avoid the occurrence of tooth tip interference, a negative displacement coefficient should be employed.

Basic parameters of the planetary transmission with small tooth difference are related and restrained mutually. In the design of the planetary transmission with less tooth difference, the accumulated experience of the former can be used as a reference to select the needed tooth difference z _p Sum of tooth top coefficientThen, the engagement angle is selected from the table.

The parameters finally determined through repeated calculation, simulation and comparison are shown in table 1. A diagram of the actual situation of the engagement after simulation is shown in fig. 6.

TABLE 1 geometric parameters of few tooth difference speed reducer

Simulation verifies that the gears have no global interference phenomenon in the meshing process, and the selected parameters are feasible.

The advantages are that:

1. the service life of the planetary bearing is long. Due to the adoption of the symmetrical double planetary wheel structure, the bearing pressure is greatly reduced, the service life of the bearing is long, and the running is stable and the noise is low.

2. The vibration and noise are small. The number of planetary gear contacts with the gear teeth of the gear ring 7 of the speed reducer is large,

3. the transmission efficiency is higher. The single-stage transmission efficiency can reach 80% -93%.

In general, the planetary reducer with small tooth difference has the advantages of simple structure, few used parts, light weight, large speed reduction ratio, good stress condition and high transmission efficiency.

The above-described embodiments of the present application do not limit the scope of the present application. Any of various other corresponding changes and modifications made according to the technical idea of the present application should be included in the scope of the claims of the present application.

Claims

1. The involute planetary gear reducer with small tooth difference and output by the belt wheel is characterized by comprising a planetary gear, a gear ring, an eccentric element and an output mechanism, wherein the output mechanism is positioned on the planetary gear and fixedly connected with a shell, and the planetary gear is arranged on the eccentric element and meshed with the gear ring, and outputs torque and motion through the output of the gear ring.

2. The involute small tooth difference planetary gear reducer with pulley output according to claim 1, characterized in that the eccentric element comprises an eccentric shaft, 2 bell cranks with 180 degrees of dislocation and 3mm eccentricity are arranged on the eccentric shaft, and the input end of the eccentric shaft is connected with an elastic pin coupling.

3. The involute low tooth differential planetary gear reducer with pulley output according to claim 2, characterized in that the planetary gear comprises a first planetary gear and a second planetary gear, and two rocker arm bearings of the first planetary gear and the second planetary gear are respectively arranged on 2 crank throws.

4. A pulley output involute low differential planetary gear reducer according to claim 3, characterized in that the number of teeth of the ring gear is 43, the number of teeth of the first planetary gear and the second planetary gear is 41, and the transmission ratio is 21.5.

5. The involute few tooth difference planetary gear reducer with pulley output according to claim 3, wherein the output mechanism comprises pin shafts and pin shaft sleeves, 6 pin shafts are arranged in cylindrical holes matched with each other on the first planet wheel and the second planet wheel, and the pin shaft sleeves are arranged on the outer sides of the pin shafts.

6. The involute few tooth difference planetary gear reducer with wheel output according to claim 5, wherein the shell is fixed on the base, the shell comprises a left support arm and a right support arm, the barrels of the left support arm and the right support arm are arranged on the eccentric shaft through a first bearing and a second bearing, and two ends of the pin shaft are respectively inserted into end walls of upper barrels of the left support arm and the right support arm.

7. The involute few tooth difference planetary gear reducer with wheel output according to claim 6, characterized in that the outer ends of the first bearing and the second bearing are respectively provided with a first bearing cover, and the first bearing covers are sleeved on the eccentric shaft and are connected with the end wall of the upper barrel body of the left support arm/the right support arm through bolts.

8. The involute few tooth difference planetary gear reducer with belt wheel output according to claim 6, characterized in that the gear ring is located between the left support arm and the right support arm and fixedly connected with the belt wheel, and the belt wheel bearings are arranged between the belt wheel and the outer walls of the left support arm and the right support arm.

9. The involute small tooth difference planetary gear reducer with pulley output according to claim 8, characterized in that second bearing covers are arranged on the outer walls of the left support arm and the right support arm, and the second bearing covers are connected with the side wall of the pulley through bolts to realize sealing to the pulley bearings.

10. A method of decelerating an involute low tooth difference planetary gear reducer with a pulley output according to any one of claims 1 to 9, characterized in that the method of decelerating comprises: