TW201408911A - Power transmission mechanism of gearbox - Google Patents

Abstract

The present invention relates to a power transmission mechanism of a gearbox, including a first ring gear, a first-stage planetary gear system, and a plurality of secondary planetary gear systems that is arranged to have central axes parallel. A first planetary gear arranged in the first-stage planetary gear system and a first transmission gear operatively coupled thereto mesh with a first sun gear and the secondary planetary gear respectively in an axis-intersecting manner, and a secondary planetary gear of the secondary planetary gear system also mesh with a secondary sun gear in an axis-intersecting manner. The first-stage planetary gear system and the secondary planetary gear systems are coupled to each other via a plurality of coupling assemblies therebetween for transmitting the rotation of the first planetary gear to the adjacent secondary planetary gear. Sun gears in each system can be selectively limited to rotate by a brake member so as to achieve the effect of gear ratio variation.

Description

Transmission power transmission mechanism

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a power transmission mechanism, and more particularly to a power transmission mechanism that utilizes a combination of a plurality of planetary gear systems.

Regarding the transmission of kinetic energy, the most common in industrial technology or everyday facilities is the use of gears. In addition to the increase and decrease of the input and output speed ratios, the gear transmission function is also often used on the input end which requires more work to reduce the force to be applied. In addition, the use of a bevel gear or the like to change the shaft angle of the conductive gear is also often used in power transmission applications requiring more degrees of freedom for work.

At present, the most common gear applications except the mechanical equipment, the most are the power transmission mechanism of the vehicle and the transmission. In particular, the automobile transmission gearbox with a relatively complicated structure utilizes the change of the gear ratio of the planetary gears to achieve the purpose of multi-speed shifting. However, these mechanisms must combine multiple sets of planetary gear systems, thereby making the whole mechanism large and complicated, and in manufacturing production. It costs a lot of money. In addition, in order to meet the needs of modern leisure, cycling has become one of the most popular ways. In order to enable the rider to overcome the resistance generated when going uphill, or to increase the speed of riding, the bicycle shifting system also A variety of gear shifting devices are available. The most common ones are flywheel combinations with different tooth diameters. With the front and rear gear ratios, the purpose of deceleration, twisting or acceleration is reduced.

When the flywheel tooth diameter is changed to achieve the purpose of shifting, in order to produce a multi-stage effect, it is often necessary to add more sprocket wheels on the front and rear sprocket wheels, thereby increasing the weight of the vehicle body and increasing the resistance of the actual ride. For this reason, there is currently a so-called internal shifting The improvement of the device is that the gear shifting mechanism is disposed in the rear wheel hub to avoid the flywheel being contaminated with dust or impact, which affects the positioning of the chain and the loss of the chain. Although it is also reducing the volume of the gear mechanism, the planetary gear system utilized is also a conventional planar configuration. Referring to the first figure, a general planetary gear system 10 includes a ring gear 11, a sun gear 12 and a plurality of planet gears 13. The ring gear 11 is disposed coaxially with the sun gear 12, and the planetary gears 13 are meshed in an annular space between the ring gear 11 and the sun gear 12, and the planetary gears 13 are rotatably disposed on a planet. On the bracket 14, when the planetary gear 13 rotates, the planetary carrier 14 is simultaneously driven to rotate. The ring gear, the sun gear and the planetary gear can be fixed at one of them, and then one component inputs power and the other component outputs. Under normal circumstances, when the planetary bracket is used as the output end, regardless of whether the sun gear or the ring gear is used as the input end, a transmission ratio greater than 1 can be generated, and the purpose of the deceleration and twisting transmission is achieved. If the planetary bracket is used as the input end, whether the sun gear or the ring gear is used as the output end, the transmission ratio can be less than 1, and the purpose of accelerating the torque reduction transmission is achieved.

Therefore, with these transmissions, in order to achieve the purpose of multi-speed shifting, it is necessary to combine multiple sets of planetary gear systems, so that the transmissions can not only reduce the weight not much, but also the volume of the internal transmission due to the radial space requirement. There is no further reduction, so that these transmissions have the disadvantage of not being able to overcome the volume and weight reduction.

In addition, the sense of frustration during shifting often occurs between gears or between the sprocket wheels, which not only makes the shifting smooth, but also reduces the comfort of the rider when riding.

On the other hand, the shifting system using an array of planetary gears, which is limited to the rotation of the sun gear, usually clamps the rotation of the sun gear by a pin on the control shaft, since the card pin is a radial single Braking on the side, often causes the sun gear to be off-axis after long-term use, which in turn affects the meshing between the relative gears. The state of the gears makes the gears use poorly.

It is an object of the present invention to provide a special planetary gear system combination that achieves different tooth ratio setting effects by selective rotation of a plurality of sun gears.

A second object of the present invention is to provide a special planetary gear system combination method, which achieves a more multi-speed shifting effect by a combination of selective rotation of a plurality of sun gears and variations of wheel diameters of different pulleys.

A further object of the present invention is to provide a special planetary gear system combination method, which is different from the conventional planetary gear system mechanism, and the planetary gear shaft and the sun gear are arranged in a shaft to reduce the planetary gear system in the radial direction. The space required, in order to reduce the volume of the power transmission mechanism of the overall transmission.

Another object of the present invention is to provide a special planetary gear system combination method, which can be applied to a relatively small shifting device or used in a shifting system of a vehicle by the effect of reducing the volume of the power transmission mechanism of the overall transmission. On the one hand, it reduces the installation space, on the other hand, it can also achieve the purpose of weight reduction due to the volume reduction.

A further object of the present invention is to provide a special planetary gear system combination method, which utilizes a pulley and a belt transmission between a plurality of planetary gear systems, and the frustration caused by the gear meshing change during the buffer shifting by the flexible characteristics of the belt. Make the shift smoother.

Another object of the present invention is to provide a special planetary gear system combination method, which allows the rider to use the shifting system of the rickshaw by utilizing the flexible characteristics of the belt and the frustration caused by the gear meshing change during the buffer shifting. Change Speed is not felt in the shift, increasing ride comfort.

A first object of the present invention is to provide a special planetary gear system combination method, which is matched with an annular braking member corresponding to a sun gear, so that the braking force of the sun gear is more evenly distributed, thereby maintaining the meshing state between the gears for a long time. Extend the life of the gear set.

In order to reduce the volume of the power transmission mechanism of the transmission, prolong the service life of the gear set, and provide a shifting effect of different gear ratios while avoiding the frustration caused by shifting, the present invention provides a power transmission mechanism for the transmission, including: a first ring gear, the first ring gear is rotatable about a central axis, and a first ring gear is axially protruded from the central axis; a first stage planetary gear system includes: a first sun gear, a first brake member, at least one first planetary gear, and at least one first transmission gear, wherein the first sun gear axially protrudes from the central axis to form a first external tooth, the first brake member is selectively The first sun gear is controlled to rotate, and each of the first planetary gears is coupled to each of the first transmission gears, and each of the first planetary gears is rotatable about a first planetary axis. The first planetary axis is perpendicular to the central axis such that the first planetary gear and the first transmission gear are respectively engageable with the first external tooth and the first ring tooth; a secondary planetary gear system, the secondary planetary gear systems and the first stage planetary gear system are juxtaposed along the central axis, each of the secondary planetary gear systems comprising: a primary gear, a second a brake member and at least one stage planetary gear, wherein the secondary sun gear axially protrudes from the central axis with a second external tooth, the second brake member selectively locking the secondary sun gear to control Rotating, each of the secondary planetary gears is rotatable about a second planetary axis, and the second planetary axis is perpendicular to the central axis such that the secondary planetary gears are engageable with the second external teeth; a second ring gear, the second ring gear is rotatable about the central axis, and a second ring is axially convex along the central axis And a plurality of coupling assemblies, each of the coupling assemblies being disposed between the first stage planetary gear system and the adjacent planetary gear systems, wherein the coupling assemblies can The rotation of a planetary gear is transmitted to the secondary planetary gear of the adjacent secondary planetary gear system; wherein the first annular tooth and the first external tooth provided by the first sun gear, the secondary sun gear The second external tooth can be arranged in the same direction as the axial direction or the opposite direction.

According to an embodiment of the present invention, the power transmission mechanism of the transmission, wherein the first brake member and the second brake members are respectively sleeved on a control adjustment rod, wherein the first brake member follows A first brake tooth is axially protruded from the central axis, and the first brake tooth can be selectively meshed with the first internal gear to be meshed with the first internal tooth of the first sun gear Rotation of the first sun gear; each of the second brake members has a second brake tooth axially protruding from the central axis, and each of the second brake teeth is selectively displaceable by each of the second brake members The second internal teeth are further engaged with each of the secondary sun gears to control the rotation of each of the secondary sun gears.

In addition, the power transmission mechanism of the transmission, each of the coupling assemblies may include: two pulleys and a belt, wherein the two pulleys and a belt, wherein the two pulley systems are coaxial with the first planetary gear and the phase Adjacent to the secondary planetary gear, or two adjacent secondary planetary gears are connected and can rotate synchronously, and the belt is wound between two adjacent pulleys.

In another embodiment, the first stage planetary gear system of the power transmission mechanism of the transmission may be further accommodated in a first bracket, and the second planetary gear systems are further respectively received in a second bracket. The last of the secondary planetary gear systems is further accommodated in a third bracket, wherein each of the sun gears is rotatably received in one of the receiving spaces of the corresponding brackets. And each of the planetary gears is rotatably fixed to each of the brackets by a bearing, and the brackets are coupled and can be driven by the rotation of the planetary gears. And rotate together around the central axis.

According to the arrangement of the sun gear and the planetary gear shaft in the embodiment of the invention, and the tandem planetary gear system configuration mode, the disadvantage of increasing the volume generated by the shifting position can be overcome. At the same time, by the selective rotation combination of the sun gear in the embodiment of the present invention, more gear ratio changes can be generated, so that the shift position is greatly increased, and it is widely utilized for different shifting requirements. In addition, through the flexible cushioning of the belt, the present invention also avoids the frustration caused by the conventional shifting, makes the shifting smoother, and provides a more comfortable feeling for the rider when used in the rickshaw.

The embodiments of the present invention are further described in the following description, and the embodiments of the present invention are set forth to illustrate the present invention, and are not intended to limit the scope of the present invention. In the scope of the invention, the scope of protection of the invention is defined by the scope of the appended claims.

Please refer to FIG. 2 to FIG. 6 at the same time, which are respectively a schematic diagram of a combination diagram, an exploded view and a gear transmission mechanism of the embodiment of the present invention. The power transmission mechanism of the transmission of the embodiment of the present invention includes a first ring gear 20, a first stage planetary gear system 30 and a plurality of secondary planetary gear systems 40. The first stage planetary gear system 30 and the plurality of secondary planetary gear systems 40 are juxtaposed with the central axis 201 as an axis.

The first ring gear 20 is rotatable about a central axis 201, and a first ring tooth 21 is axially protruded from the central axis 201. The first ring teeth 21 may be disposed in the axial direction at both ends, and the teeth may be in the form of an umbrella gear or a spur gear. The first ring gear 20 can be provided with an external thread 22 on the outer circumferential surface thereof, thereby The pieces are connected as the input or output of the power.

The first stage planetary gear system 30 includes a first sun gear 31, a first brake member 37, at least one first planet gear 32, and at least one first transmission gear 34. The first sun gear 31 is also pivoted about the central axis axis 201. A first outer tooth 311 and a first inner tooth 312 are axially protruded from the central axis 201. The tooth forms are It is an umbrella gear or a spur gear, but it is not limited to this. The first brake member 37 can be sleeved on a control adjustment rod 60. A first brake tooth 371 is axially protruded from the central axis 201. The first brake tooth 371 can be selectively selected by the first brake member 37. The first inner tooth 312 provided by the first sun gear 31 is meshed to move, thereby controlling the rotation of the first sun gear 31.

The first planetary gears 32 are provided with at least one, preferably two or more. When a plurality of the first planetary gears 32 are provided, it is preferably arranged in an equiangular distribution, so that the power transmission is more stable, and the friction between the gear teeth is reduced and extended. Gear life. Each of the first planetary gears 32 is coupled to the first transmission gear 34 by a rotating shaft 33, and the two are rotated in conjunction. The first planetary gear 32 and the first transmission gear 34 rotate about the first planetary axis 301, and the first planetary axis 301 is perpendicular to the central axis 201, so that the first planetary gear 32 is coupled to the first sun gear. The first outer teeth 311 of the 31 are engaged, and the first transmission gear 34 meshes with the first ring teeth 21 of the first ring gear 20. However, the axial angle of the first planetary axis 301 and the central axis 201 is not limited thereto, and 60 degrees or 120 degrees is also an angle commonly used in applications, so that it is a preferred axis within 60 degrees to 120 degrees. Angle range. In conjunction with the change in the shaft angle, the first outer teeth 311 and the first planetary gears 32, and the first ring gear 21 and the first transmission gear 34 are meshed with any form of gear that can be engaged. The gears may be shaft intersecting gears, and the shaft angle may be between 60 degrees and 120 degrees, but not limited thereto, wherein 90 degrees is optimal. At this time, the gear form can be selected with a straight-toothed umbrella gear, which is further reduced by the characteristics of large rigidity and small volume. The volume of the embodiment of the invention is reduced. In addition, in order to further meet the requirements of low noise, high load and high speed, curved bevel gears can also be used, but not limited thereto.

The secondary planetary gear system 40 can be provided with only one or a plurality of, and when there are a plurality of gears, the tooth ratio change will be more abundant. A plurality of secondary planetary gear systems 40 or between the secondary planetary gear system 40 and the first stage planetary gear system 30 are juxtaposed along the central axis 201.

Each of the secondary planetary gear systems 40 includes a primary sun gear 41, a second brake 47, and at least a primary planetary gear 42. The secondary sun gear 41 is also pivoted about the central axis 201. A second outer tooth 411 and a second inner tooth 412 are axially protruded from the central axis 201. The tooth forms may be Bevel gear or spur gear, but not limited to this. The second brake member 47 can be sleeved on a control adjustment rod 60. A second brake tooth 471 is axially protruded from the central axis 201. The second brake tooth 471 can be selectively selected by the second brake member 47. The second internal tooth 412 provided in the secondary sun gear 41 is moved to mesh, thereby controlling the rotation of the secondary sun gear 41.

The secondary planetary gears 42 are provided with at least one, preferably two or more. When a plurality of the plurality of planetary gears 42 are provided, it is preferably arranged at an equiangular distribution, so that the power transmission is more stable, and the friction between the gear teeth is reduced and extended. Gear life. The secondary planetary gear 42 rotates about the secondary planetary axis 401, and the secondary planetary axis 401 is perpendicular to the central axis 201, such that the secondary planetary gear 42 is coupled to the second external tooth of the secondary sun gear 41. 411 is engaged. However, the axial angle of the secondary planetary gear 42 and the central axis 201 is not limited thereto, and 60 degrees or 120 degrees is also an angle commonly used in applications, so that it is a preferred axis within 60 degrees to 120 degrees. Angle range. In conjunction with the change in the shaft angle, the engaged second outer teeth 311 and the secondary planetary gears 42 are selected to be engageable in any form of gear. The gears may be shaft intersecting gears, and the shaft angle may be between 60 degrees and 120 degrees, but not limited thereto, wherein 90 degrees is optimal. At this time, the gear form can be selected from a straight bevel gear. The volume of the embodiment of the present invention is further reduced by the characteristics of its large rigidity and small volume. In addition, in order to further meet the requirements of low noise, high load and high speed, curved bevel gears can also be used, but not limited thereto.

Between the first stage planetary gear system 30 and the adjacent secondary planetary gear system 40, and between the adjacent secondary planetary gear systems 40, the plurality of coupling assemblies 50 are connected and driven. The rotation of the first planet gears 32 is transmitted to the secondary planet gears 42 of the adjacent secondary planetary gear system 40.

Each of the coupling assemblies 50 includes: a second pulley 51 and a belt 52. The two pulleys 51 are coaxially connected to the first planetary gear 32 and the secondary planetary gear 42 by the rotating shafts 33 and 43 respectively, and can be synchronized with the same. Rotating, or two coaxial shafts 43 are respectively coaxially connected with the two adjacent secondary planetary gears 42 and can be rotated synchronously; a belt 52 is respectively disposed between the adjacent two pulleys 51.

In the embodiment of the present invention, the first stage planetary gear system 30 can be further disposed in a first bracket 35, and the second planetary gear systems 40 are respectively received in a second bracket 44. The last of the secondary planetary gear systems 40 is housed in a third bracket 48. The first sun gear 31 and the secondary sun gear 41 are rotatably respectively received in one of the accommodating spaces 351, 441 and 481 provided in the corresponding brackets, and the first planetary gear 32 and the secondary planet The gears 42 are rotatably fixed to the brackets in the mounting holes 352, 442 and 483 by bearings 36 and 46, respectively.

The first bracket 35 and the third bracket 48 are respectively provided with a plurality of fixing holes 353 and 482, and the second brackets 44 are respectively provided with a plurality of slots 443. The brackets are connected by a plurality of fixing rods 45 corresponding to the grooves 443 and the fixing holes 353 and 482. The brackets are rotatable together about the central axis 201 by the rotation of the planetary gears.

Please refer to the fifth, sixth and seventh figures, which are in the embodiment of the present invention. A schematic diagram of the gear transmission mechanism. The power transmission mechanism of the transmission of the embodiment of the present invention can be used as the input end of the power by the first ring gear 20. When the first ring gear 20 rotates, the first transmission gear 34 meshing with the first ring gear 21 will rotate synchronously. The rotation of the first transmission gear 34 simultaneously drives the rotation of the coupled first planetary gear 32 and the pulley 51. When the first planetary gear 32 rotates, the first sun gear 31 that is meshed is further driven. At this time, in addition to the loss of friction or axial force, the input power does not vary with the idling of the first sun gear. After the pulley 51 rotates, the rotation of the adjacent pulleys 51 is successively driven, and the secondary sun gears 41 of the adjacent secondary planetary gear systems 40 are further rotated. When the sun gear in each of the planetary gear systems is selectively restricted by the braking member, the planetary gears in the planetary gear system will rotate in the opposite direction in the axial direction, thereby driving the rotation of the bracket and the power of the input. The difference in transmission ratio is produced. Therefore, by combining the various sun gears to limit the rotation and the gear ratio setting by the embodiment of the present invention, a plurality of gear ratio combinations can be produced, and the utility model can be applied to various shifting systems.

In addition, in the embodiment of the present invention, the first ring teeth 21 and the first outer teeth 311 and the second outer teeth 411 are disposed in opposite axial directions, and the rotation direction of the first ring teeth 21 during the gear transmission will be just right. The rotation direction of the first sun gear 31 and the secondary sun gear 41 is opposite. Therefore, the present invention can also be utilized in the shifting system of the reverse gear by the change of the output end and the input end. On the contrary, if the first ring gear 21 and the first outer tooth 311 and the second outer tooth 411 are disposed in the same axial direction, the rotation direction of the first ring gear 21 and the first sun gear 31 when the gear is driven. The rotation direction of the secondary sun gear 41 is the same.

On the other hand, the embodiment of the present invention also needs to change the design mode of the input end of the first ring gear 20, or change the transmission mode by the bracket as the input end or the output end to apply to different needs.

Please refer to the eighth figure, which is a schematic view of another embodiment of the present invention. This hair In the embodiment, the power transmission mechanism of the transmission is also applied to the bicycle rear wheel hub, and through the combination with the sprocket 70 and the clutch 71, the bicycle has a multi-stage shifting effect. A thread (not shown) may be further disposed on the clutch 71 as a fixed position of the power output or the input end.

10‧‧‧ planetary gear system

11‧‧‧ring gear

12‧‧‧Sun Gear

13‧‧‧ planetary gear

14‧‧‧ Planetary bracket

20‧‧‧First ring gear

201‧‧‧ center axis

21‧‧‧First ring tooth

22‧‧‧ external thread

30‧‧‧First stage planetary gear system

301‧‧‧First planetary axis

31‧‧‧First sun gear

311‧‧‧First external tooth

312‧‧‧First internal tooth

32‧‧‧First planetary gear

33‧‧‧ shaft

34‧‧‧First transmission gear

35‧‧‧First bracket

351‧‧‧ accommodating space

352‧‧‧Installation holes

353‧‧‧Fixed holes

36‧‧‧ Bearing

37‧‧‧First brake

371‧‧‧First brake tooth

40‧‧‧Secondary planetary gear system

401‧‧‧second planetary axis

41‧‧‧Second sun gear

411‧‧‧Second external teeth

412‧‧‧Second internal tooth

42‧‧‧Secondary planetary gears

43‧‧‧ shaft

44‧‧‧second bracket

441‧‧‧ accommodating space

442‧‧‧Installation holes

443‧‧‧ Groove

45‧‧‧Fixed rod

46‧‧‧ bearing

47‧‧‧Second brake

471‧‧‧Second brake teeth

48‧‧‧ Third bracket

481‧‧‧ accommodating space

482‧‧‧Fixed holes

483‧‧‧Installation holes

50‧‧‧ coupling assembly

51‧‧‧ Pulley

52‧‧‧Land

60‧‧‧Control adjustment lever

70‧‧‧Sprocket

71‧‧‧Clutch

The first figure is a schematic diagram of a conventional planetary gear system.

The second drawing is a schematic view of an embodiment of the invention.

The third figure is an exploded perspective view of an embodiment of the present invention.

The fourth figure is another exploded perspective view of an embodiment of the present invention.

The fifth figure is a schematic view of a planetary gear mechanism in an embodiment of the present invention.

Figure 6 is a side elevational view of the planetary gear mechanism of the embodiment of the present invention.

The seventh figure is a top view of the planetary gear mechanism in the embodiment of the present invention.

The eighth figure is a schematic view of another embodiment of the present invention.

20‧‧‧First ring gear

21‧‧‧First ring tooth

31‧‧‧First sun gear

311‧‧‧First external tooth

32‧‧‧First planetary gear

34‧‧‧First transmission gear

41‧‧‧Second sun gear

411‧‧‧Second external teeth

412‧‧‧Second internal tooth

42‧‧‧Secondary planetary gears

47‧‧‧Second brake

471‧‧‧Second brake teeth

50‧‧‧ coupling assembly

51‧‧‧ Pulley

52‧‧‧Land

60‧‧‧Control adjustment lever

Claims (18)

A power transmission mechanism of a transmission includes: a first ring gear, the first ring gear is rotatable about a central axis, and a first ring gear is axially protruded from the central axis; a first stage planetary gear system, The first sun gear, a first brake member, at least one first planetary gear, and at least one first transmission gear, wherein the first sun gear axially protrudes from the central axis to form a first external tooth The first braking member can selectively lock the first sun gear to control the rotation thereof, and each of the first planetary gears is coupled to each of the first transmission gears and correspondingly disposed, and each of the first planetary gears can be wound a first planetary axis is rotated, and the first planetary axis is perpendicular to the central axis such that the first planetary gear and the first transmission gear are respectively engageable with the first external tooth and the first ring tooth a plurality of secondary planetary gear systems, the secondary planetary gear systems and the first stage planetary gear system being juxtaposed along the central axis, each of the secondary planetary gear systems comprising: a primary sun a second brake member and at least a primary planetary gear, wherein the secondary sun gear axially protrudes from the central axis with a second external tooth, the second brake member selectively clamping the secondary The sun gear controls its rotation, and each of the secondary planetary gears is rotatable about a second planetary axis, and the second planetary axis is perpendicular to the central axis, so that the secondary planetary gear can be coupled to the second external tooth Engaging; and a plurality of coupling assemblies, each of the coupling assemblies being disposed between the first stage planetary gear system and the adjacent one of the secondary planetary gear systems, and the adjacent secondary planetary gears Between the systems, the coupling assemblies transmit the rotation of the first planetary gear to the secondary planetary gear of an adjacent secondary planetary gear system. The power transmission mechanism of the transmission of claim 1, wherein The first brake member and the second brake member are respectively sleeved on a control adjustment rod, wherein the first brake member has a first brake tooth axially protruding along the central axis, and the first brake tooth can be Controlling the rotation of the first sun gear by the first inner gear being further engaged by the first sun gear, and controlling the rotation of the first sun gear; each of the second brake members follows A second brake tooth is axially protruded from the central axis, and each of the second brake teeth is further displaceable by each of the second brake members to further provide a second internal tooth phase with each of the secondary sun gears. Engage, and control the rotation of each of the secondary sun gears. The power transmission mechanism of the transmission of claim 1, wherein the first ring tooth and the first outer tooth of the first sun gear and the second outer tooth of the second sun gear are provided. The dental system is set in the same axial direction. The power transmission mechanism of the transmission of claim 1, wherein the first ring tooth and the first outer tooth of the first sun gear and the second outer tooth of the second sun gear are provided. The dentition is placed in the opposite axial direction. The power transmission mechanism of the transmission of claim 2, wherein the correspondingly engaged sun gear and planetary gear are umbrella gears. The power transmission mechanism of the transmission of claim 2, wherein the correspondingly engaged ring gears and transmission gears are bevel gears. The power transmission mechanism of the transmission of claim 2, wherein each of the coupling assemblies comprises: a second pulley and a belt, wherein the two pulleys are coaxial with the first planetary gear and adjacent to the second The planetary gears, or two adjacent secondary planetary gears, are connected to each other and can rotate synchronously, and the belt is wound between two adjacent pulleys. The power transmission mechanism of the transmission of claim 7, wherein the correspondingly engaged sun gear and the planetary gear are shaft intersecting gears. The power transmission mechanism of the transmission of claim 8, wherein the axial angle between the correspondingly engaged sun gear and the planetary gear is 90 degrees. The power transmission mechanism of the transmission of claim 8, wherein the correspondingly engaged sun gears and planetary gears are bevel gears. The power transmission mechanism of the transmission of claim 10, wherein the correspondingly engaged sun gears and planetary gears are curved bevel gears. The power transmission mechanism of the transmission of claim 1, wherein each of the coupling assemblies comprises: two pulleys and a belt, wherein the two pulleys and a belt, wherein the two pulley systems are coaxial with the first A planetary gear and the adjacent secondary planetary gear, or two adjacent secondary planetary gears are connected to each other and can rotate synchronously, and the belt is wound between two adjacent pulleys. The power transmission mechanism of the transmission of claim 12, wherein the correspondingly engaged sun gear and the planetary gear are umbrella gears. The power transmission mechanism of the transmission of claim 1, wherein the first sun gear and the first planetary gear that are correspondingly engaged are umbrella gears. The power transmission mechanism of the transmission of claim 1, wherein the first ring gear and the first transmission gear that are correspondingly engaged are umbrella gears. The power transmission mechanism of the transmission of claim 1, wherein the first stage planetary gear system is further disposed in a first bracket, and the second planetary gear systems are further respectively received in a second bracket Medium, and the last of the secondary planetary gear systems is further accommodated in a third In the bracket, each of the sun gears is rotatably received in one of the receiving spaces of the corresponding brackets, and each of the planetary gears is rotatably fixed to each of the brackets by a bearing The brackets are coupled to each other and can be rotated about the central axis by the rotation of the planetary gears. The power transmission mechanism of the transmission of claim 16, wherein the first bracket and the third bracket are respectively provided with a plurality of fixing holes, and the second brackets are respectively provided with a plurality of grooves, The brackets are connected by a plurality of fixing rods corresponding to the grooves and the fixing holes. The power transmission mechanism of the transmission of claim 17, wherein the two ends of the fixing rod are respectively inserted into the fixing holes corresponding to the first bracket and the third bracket, The fixing rods are respectively pressed onto the corresponding grooves provided on the second brackets, and the first brackets, the second brackets and the third brackets are respectively connected and fixed.