CN115479112A

CN115479112A - Planetary gear reducer capable of shifting

Info

Publication number: CN115479112A
Application number: CN202211033772.6A
Authority: CN
Inventors: 苟中超
Original assignee: Quanzhou Zhonghaituo Intelligent Technology Co ltd
Current assignee: Quanzhou Zhonghaituo Intelligent Technology Co ltd
Priority date: 2022-08-26
Filing date: 2022-08-26
Publication date: 2022-12-16

Abstract

The invention belongs to the field of speed reducers, and particularly relates to a planetary gear speed reducer capable of shifting. A planetary gear reducer capable of shifting comprises a shell, an input shaft, a movable shaft, a sun gear, a planet carrier, a fixed gear ring and an output shaft, wherein the input shaft, the movable shaft, the sun gear, the planet carrier, the fixed gear ring and the output shaft are arranged in the shell and are coaxially arranged; the planet carrier is fixedly connected with the output shaft, a plurality of planetary wheel mechanisms which are arranged in an array mode in the rotating direction of the planet carrier in a winding mode are arranged on the planet carrier, and the fixed gear ring is arranged outside the planetary wheel mechanisms in a winding mode and meshed with the planetary wheel mechanisms; the planet carrier is provided with a shaft hole arranged along the axial direction, one end of the shaft hole is provided with an inner tooth part which protrudes inwards, and the other end of the shaft hole is provided with a yielding space; the outer wall of loose axle is equipped with the outer tooth portion that sets up of protrusion outwards, and the sun gear is located loose axle one end and is extended forward, and the loose axle rotates with the input shaft synchronization, and the loose axle can move about to primary importance or second place along the input shaft axis direction to realize the variable speed operation of shifting of reduction gear.

Description

Planetary gear reducer capable of shifting

Technical Field

The invention belongs to the field of speed reducers, and particularly relates to a planetary gear speed reducer capable of shifting.

Background

The reducer is an independent part consisting of gear transmission, worm transmission and gear-worm transmission enclosed in a rigid shell, and is commonly used as a speed reduction transmission device between a prime mover and a working machine. The function of matching the rotation speed and transmitting the torque between the prime mover and the working machine or the actuating mechanism is very extensive in modern machinery. The speed reducers are various in kind and can be classified into gear speed reducers, worm speed reducers and planetary gear speed reducers according to the transmission types. The planetary gear reducer drives the planetary gear to rotate in the gear ring through the sun gear connected with the motor spindle, so that the planetary gear drives the output shaft to rotate to obtain larger torque and realize a speed reduction effect. The planetary gear reducer has the advantages of compact structure, small volume and long service life, and the application scene is a complex environment with small space and does not need frequent maintenance and inspection. When the transmission ratio needs to be changed, the installation space is small, the structure of the reducer is complex, and the reducer is difficult to replace and needs to be improved.

Disclosure of Invention

The object of the present invention is to overcome the disadvantages of the prior art and to provide a shiftable planetary gear reducer.

The invention adopts the following technical scheme:

a gear-changeable planetary gear reducer comprises a shell, an input shaft, a movable shaft, a sun gear, a planet carrier, a fixed gear ring and an output shaft, wherein the input shaft, the movable shaft, the sun gear, the planet carrier, the fixed gear ring and the output shaft are arranged in the shell and are coaxially arranged;

the planet carrier is fixedly connected with the output shaft, a plurality of planetary gear mechanisms which are arranged in an array mode in the rotating direction of the planet carrier in a winding mode are arranged on the planet carrier, and the fixed gear ring is arranged outside the planetary gear mechanisms in a winding mode and meshed with the planetary gear mechanisms; the planet carrier is provided with a shaft hole arranged along the axial direction, one end of the shaft hole is provided with an inner tooth part protruding inwards, and the other end of the shaft hole is provided with a abdicating space;

the outer wall of the movable shaft is provided with an outer tooth part which protrudes outwards, the sun wheel is arranged at one end of the movable shaft and extends forwards, the movable shaft and the input shaft rotate synchronously, and the movable shaft can move to a first position or a second position along the axis direction of the input shaft;

the movable shaft is in a first position state: the outer tooth part of the movable shaft is meshed with the inner tooth part of the planet carrier, and meanwhile, the sun gear is positioned in the abdicating space and separated from each planet gear mechanism; the movable shaft is in a second position state: the outer tooth portion of the movable shaft is located in the yielding space and separated from the inner tooth portion, and meanwhile the sun gear is placed between the planet gear mechanisms and meshed with the planet gear mechanisms.

Preferably, the planetary gear mechanism comprises wheel shafts and planetary gears, and the wheel shafts are circumferentially arrayed on the planet carrier around the rotation direction of the planet carrier; the fixed gear rings of the planet gears are meshed and are arranged on the wheel shafts in a one-to-one correspondence manner.

Preferably, the planet carrier comprises a rotary disc, a connecting ring and a connecting piece, the rotary disc is connected with the tail end of the output shaft, and the wheel shaft is arranged on the rotary disc; the planet wheel is arranged between the connecting ring and the rotary table, and the internal tooth part is formed on the connecting ring; the connecting piece is connected between the turntable and the connecting ring.

Preferably, the gear shifting mechanism is further included, the gear shifting mechanism can drive the movable shaft to move to the first position or the second position on the output shaft, the gear shifting mechanism includes a driving piece and a positioning piece, and the driving piece can drive the movable shaft to move back and forth on the output shaft; the positioning piece is arranged on the movable shaft and used for positioning a first position and a second position, and comprises a sliding ring, a first positioning hole, a second positioning hole and a positioning component, wherein the sliding ring is connected between the driving piece and the movable shaft and can be switched between the first position and the second position along with the driving piece; the first positioning hole and the second positioning hole are formed outwards from the inner wall of the shell, are distributed along the direction of the rotation axis and are respectively opposite to the positions of the sliding rings at the first position and the second position; the positioning component can respectively extend into the first positioning hole and the second positioning hole at the first position and the second position to play a positioning role.

Preferably, the positioning assembly comprises a positioning groove, a positioning spring and a positioning ball; the positioning groove is formed inwards from the outer side surface of the sliding ring and can be respectively opposite to the first positioning hole and the second positioning hole when in a first position and a second position; the positioning spring is arranged in the positioning groove; the positioning ball is arranged in the positioning groove and can be embedded into the positioning groove under the action of the positioning spring.

Preferably, the driving member comprises a first bearing, a sleeve, a driving rod and a sliding chute, and the first bearing is sleeved between the sliding ring and the movable shaft and can move back and forth along with the sliding ring and the movable shaft; the sliding chute is formed on the shell to communicate the space inside and outside the shell; the sleeve is sleeved on the shell and used for sealing the sliding chute; the driving rod penetrates through the sleeve and the sliding groove in sequence to extend into the shell to be connected with the sliding ring, and the driving rod can move back and forth along the extending direction of the sliding groove and drive the movable shaft to move to a first position or a second position.

Preferably, the loose axle outside from the bottom surface shaping of upwards caving in has first shaft shoulder, is provided with first spacing ring on the first shaft shoulder, first bearing medial surface joint is between first shaft shoulder and first spacing ring, the slip ring inboard has the second shaft shoulder from the shaping of the bottom surface upwards caving in, is provided with the second spacing ring on the second shaft shoulder, first bearing lateral surface joint is between second shaft shoulder and second spacing ring.

Preferably, the loose axle with through splined connection between the input shaft, the shaping has the first keyway that supplies the spline to pass on the loose axle, the shaping second keyway that supplies the spline to pass on the input shaft, spline one end and second keyway fixed connection, the other end and first keyway sliding connection make the loose axle keep and can follow the axis direction under the synchronous transmission state with the input shaft and move about to primary importance or second place.

Preferably, the connecting piece comprises a first screw hole, a second screw hole, a limiting sleeve and a fixing bolt, and the first screw hole is formed in the connecting ring in a penetrating mode; the second screw hole is formed on the rotary disc and is opposite to the first screw hole; the limiting sleeve is connected between the rotary table and the connecting ring and enables the first screw hole to be communicated with the second screw hole; the fixing bolt sequentially penetrates through the first screw hole, the limiting sleeve and the second screw hole to fix the connecting ring on the rotary table, so that a space for accommodating the planet wheel is formed between the connecting ring and the rotary table.

Preferably, the width of the outer teeth and the width of the inner teeth are smaller than the distance from the first position to the second position.

As can be seen from the above description of the present invention, compared with the prior art, the beneficial effects of the present invention are: the change of the transmission ratio is realized by switching the movable shaft between the first position and the second position, the adjustment of the transmission ratio can be carried out without detaching the speed reducer, the efficiency and the convenience are high, the planetary gear transmission is accurate, and the verification of the transmission ratio after the transmission ratio is adjusted is not needed;

when the sliding ring drives the movable shaft to move to the first position or the second position, the positioning assembly respectively extends into the first positioning hole and the second positioning hole under the action of the spring to achieve the fixing effect;

the spring drives the positioning piece to move into the positioning hole to play a role in fixing, and the force applied to the driving piece is gradually increased when the gear is shifted, so that the positioning ball slides out of the positioning hole and reenters the positioning groove, and the fixed state is switched to the free state;

the sliding ring is moved by pushing the driving rod extending out of the shell, the movable shaft is driven to move, so that gear shifting is realized, the operation is simple, the speed reducer is not required to be opened, and meanwhile, the sleeve is sleeved outside the sliding chute, so that the lubricant in the speed reducer can be prevented from flowing out of the sliding chute;

the first bearing is fixed on the external tooth part through the matching of the shaft shoulder and the limiting ring, so that the bearing is prevented from falling off when the driving rod is pushed to move, and the safety and the stability of the device are improved;

the movable shaft is movably arranged on the spline, the spline is accurate in transmission and large in load, and the transmission efficiency is ensured while the movable shaft is movable;

the limiting sleeve is connected between the connecting ring and the rotary table to play a limiting role, so that the connecting ring and the rotary table keep a certain gap when the connecting ring is locked by the bolt, and the influence on the use of the speed reducer caused by the contact of the connecting ring with the planet wheel is avoided;

the width of the outer tooth part and the width of the inner tooth part are smaller than the distance from the first position to the second position, and only one pair of gears are meshed when the first position and the second position are switched, namely, only the sun gear is meshed with the planet gear or the inner tooth part is meshed with the outer tooth part.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a partial cross-sectional view of the first embodiment of the present invention;

FIG. 3 is a partial sectional view of the second embodiment of the present invention;

FIG. 4 is a transverse cross-sectional view of the first embodiment of the present invention;

FIG. 5 is a transverse cross-sectional view of the second embodiment of the present invention;

FIG. 6 is a longitudinal cross-sectional view of the first embodiment of the present invention;

FIG. 7 is a second longitudinal cross-sectional view of the present invention;

FIG. 8 is an enlarged view of a portion of FIG. 2 at A;

FIG. 9 is an enlarged view of a portion of FIG. 3 at B;

in the figure: 1-shell, 11-second bearing, 2-output shaft, 3-planet carrier, 31-planet wheel mechanism, 311-wheel shaft, 312-planet wheel, 32-shaft hole, 33-internal tooth part, 34-rotary disc, 35-connecting ring, 351-mounting groove, 36-connecting piece, 361-first screw hole, 362-second screw hole, 363-limit sleeve, 364-fixed bolt, 4-fixed gear ring, 5-movable shaft, 51-external tooth part, 52-first key groove, 53-mounting hole, 54-first shaft shoulder, 55-first limit ring, 56-second shaft shoulder, 57-second limit ring, 6-sun wheel, 7-input shaft, 71-spline, 72-second key groove, 73-third bearing, 8-gear shifting mechanism, 81-driving piece, 811-first bearing, 812-sleeve, 813-driving rod, 814-sliding groove, 82-positioning piece, 821-sliding ring, 822-first positioning hole, 823-second positioning hole, 824-positioning assembly, 41-8242-positioning spring and 8243-positioning ball positioning groove.

Detailed Description

The invention is further described below by means of specific embodiments.

Referring to fig. 1 to 7, a shiftable planetary gear reducer includes a housing 1, an output shaft 2, a carrier 3, a fixed ring gear 4, a movable shaft 5, a sun gear 6, an input shaft 7, and a shift mechanism 8.

The output shaft 2, the planet carrier 3, the fixed gear ring 4, the movable shaft 5, the sun gear 6 and the input shaft 7 are arranged in the shell 1 and are arranged along the same axis.

The planet carrier 3 is fixedly connected with the output shaft 2, the planet carrier 3 is provided with a plurality of planet wheel mechanisms 31 which are arranged in an array mode around the rotation direction of the planet carrier 3, the fixed gear ring 4 is arranged outside the planet wheel mechanisms 31 in a winding mode and meshed with the planet wheel mechanisms 31, each planet wheel mechanism 31 comprises a wheel shaft 311 and a planet wheel 312, and the wheel shafts 311 are arranged on the planet carrier 3 in a circumferential array mode around the rotation direction of the planet carrier 3; the planet wheels 312 are meshed with the fixed ring gear 4 and are arranged on the wheel shafts 311 in one-to-one correspondence with the wheel shafts 311.

Be provided with the shaft hole 32 that arranges along axial direction on the planet carrier 3, shaft hole 32 one end is equipped with the protruding interior tooth portion 33 that sets up inwards, and the other end is formed with the space of stepping down.

Specifically, the planet carrier 3 comprises a rotary disc 34, a connecting ring 35 and a connecting piece 36, the rotary disc 34 is connected with the tail end of the output shaft 2, and the wheel shaft 311 is arranged on the rotary disc 34; the connecting ring 35 is connected with the rotating disc 34 and rotates synchronously with the rotating disc, the planet wheel 312 is arranged between the connecting ring 35 and the rotating disc 34, and the internal tooth part 33 is formed on the connecting ring 35; the connecting piece 36 is connected between the rotating disc 34 and the connecting ring 35. The connecting piece 36 comprises a first screw hole 361, a second screw hole 362, a limiting sleeve 363 and a fixing bolt 364, wherein the first screw hole 361 is formed on the connecting ring 35 in a penetrating mode; a second screw hole 362 formed on the rotary plate 34 opposite to the first screw hole 361; the limiting sleeve 363 is connected between the rotary disc 34 and the connecting ring 35 and enables the first screw hole 361 to be communicated with the second screw hole 362; the fixing bolt 364 passes through the first screw hole 361, the limiting sleeve 363 and the second screw hole 362 in sequence to fix the connecting ring 35 on the rotary disc 34, so that a space for accommodating the planet wheel 312 is formed between the connecting ring 35 and the rotary disc 34. Further, the connecting ring 35 is formed with a mounting groove 351 which is coaxially disposed with the first screw hole 361 and can be used for positioning the limiting sleeve 363, so as to facilitate mounting of the limiting sleeve 363.

The outer wall of the movable shaft 5 is provided with an outer tooth part 51 protruding outwards, the sun gear 6 is arranged at one end of the movable shaft 5 and extends forwards, the movable shaft 5 and the input shaft 7 rotate synchronously, and the movable shaft 5 can move to a first position or a second position along the axis direction of the input shaft 7. The movable shaft 5 is in the first position state: the external tooth part 51 of the movable shaft 5 is meshed with the internal tooth part 33 of the planet carrier 3, and simultaneously the sun gear 6 is positioned in the abdicating space and the sun gear 6 is separated from each planet gear mechanism 31; the movable shaft 5 is in the second position state: the external gear 51 of the movable shaft 5 is located in the relief space and separated from the internal gear 33, and the sun gear 6 is interposed between the planetary gear mechanisms 31 and engaged with the planetary gear mechanisms 31. Through the removal of drive loose axle 5 on input shaft 7, realize shifting fast, need not to dismantle the reduction gear, have very high practicality.

Concretely, be connected through spline 71 between loose axle 5 and the input shaft 7, the shaping has the first keyway 52 that supplies spline 71 to pass on the loose axle 5, the shaping second keyway 22 that supplies spline 21 to pass on the input shaft 7, spline 21 one end and second keyway 22 fixed connection, the other end and first keyway 52 sliding connection make loose axle 5 keep and can follow the axis direction under the synchronous transmission state with input shaft 7 and move about to primary importance or secondary importance, loose axle 5 is portable to be set up on spline 21, the transmission of spline 21 is accurate, load is big, guarantee transmission efficiency when loose axle 5 is mobilizable. The first key groove 52 is formed upward from the bottom surface of the loose axle 5, and a mounting hole 53 for mounting the sun gear 6 is formed downward from the top surface of the loose axle 5, and the sun gear 6 is arranged in the mounting hole 53 in an interference fit manner.

Further, the width of the external teeth 51 and the internal teeth 33 is smaller than the distance from the first position to the second position, and the width of the external teeth 51 and the internal teeth 33 is smaller than the distance from the first position to the second position, so that only one pair of gears is meshed when switching between the first position and the second position, namely only the sun gear 6 is meshed with the planet gears 312 or the internal teeth 33 are meshed with the external teeth 51.

The gear shifting mechanism 8 can drive the movable shaft 5 to move to the first position or the second position on the input shaft 7, the gear shifting mechanism 8 comprises a driving member 81 and a positioning member 82, and the driving member 81 can drive the movable shaft 5 to move back and forth on the input shaft 7; the positioning element 82 is disposed on the movable shaft 5 for positioning a first position and a second position, and includes a sliding ring 821, a first positioning hole 822, a second positioning hole 823 and a positioning assembly 824, the sliding ring 821 is connected between the driving element 81 and the movable shaft 5, and can be switched between the first position and the second position along with the driving element 81; the first positioning hole 822 and the second positioning hole 823 are formed outward from the inner wall of the housing 1, distributed along the rotation axis direction, and respectively opposite to the first position and the second position lower slide ring 821; the positioning assembly 824 can extend into the first positioning hole 822 and the second positioning hole 823 respectively at the first position and the second position for positioning. When the sliding ring 821 drives the movable shaft 5 to move to the first position or the second position, the positioning assembly 824 extends into the first positioning hole 822 and the second positioning hole 823 respectively to achieve the fixing effect.

The positioning assembly 824 includes a positioning slot 8241, a positioning spring 8242 and a positioning ball 8243; the positioning groove 8241 is formed inwards from the outer side surface of the sliding ring 821 and can respectively correspond to the first positioning hole 822 and the second positioning hole 823 at the first position and the second position; a positioning spring 8242 is disposed in the positioning groove 8241; a positioning ball 8243 is disposed in the positioning slot 8241 and can be embedded in the positioning slot 8241 under the action of a positioning spring 8242. The diameter of location ball 8243 is greater than the aperture of constant head tank 8241, drives setting element 82 through the spring and removes to play fixed effect in the locating hole, increases gradually when shifting gears and applies force to driving piece 81, makes location ball 8243 follow the roll-off in the locating hole and reentrant constant head tank 8241, realizes switching to the free state from fixed state.

The driving member 81 includes a first bearing 811, a sleeve 812, a driving rod 813 and a sliding chute 814, wherein the first bearing 811 is sleeved between the sliding ring 821 and the movable shaft 5 and can move back and forth therewith; the chute 814 is formed on the shell 1 to communicate the space inside and outside the shell 1; the sleeve 812 is sleeved on the shell 1 and used for sealing the chute 814; the driving rod 813 passes through the sleeve 812 and the sliding slot 814 in sequence and extends into the housing 1 to be connected with the sliding ring 821, and the driving rod 813 can move back and forth along the extending direction of the sliding slot 814 and drive the movable shaft 5 to move to the first position or the second position. Realize the removal of slip ring 821 through promoting the actuating lever 813 that extends to the casing 1 outside, thereby it shifts to drive loose axle 5 and remove the realization, easy operation need not to open the reduction gear, and sleeve 812 cover is established and is can avoid the emollient in the reduction gear to flow out from spout 814 outside spout 814 simultaneously.

Specifically, a first shaft shoulder 54 is formed on the outer side of the movable shaft 5 in a concave manner from the bottom surface to the top, a first limit ring 55 is arranged on the first shaft shoulder 54, the inner side surface of the first bearing 811 is clamped between the first shaft shoulder 54 and the first limit ring 55, a second shaft shoulder 56 is formed on the inner side of the sliding ring 821 in a concave manner from the bottom surface to the top, a second limit ring 57 is arranged on the second shaft shoulder 56, and the outer side surface of the first bearing 811 is clamped between the second shaft shoulder 56 and the second limit ring 57. The first bearing 811 is fixed on the external tooth part through the matching of the shaft shoulder and the limiting ring, so that the bearing is prevented from falling off when the driving rod 813 is pushed to move, and the safety and the stability of the device are improved.

The input shaft 7 is specifically a coupling which can be connected with a motor spindle, and is not a key point of the present application, and further details on the structure and selection of the input shaft are not described here. At the same time, the device also comprises a second bearing 11 arranged between the output and the housing 1 and a third bearing 73 arranged between the input shaft 7 and the housing 1.

When the gear is shifted from high speed to low speed (i.e. from the first position to the second position), the motor is stopped, the driving rod 813 is driven by hand to move upwards, so that the positioning ball 8243 is gradually moved out of the first positioning hole 822 under the action of external force, the sliding ring 821 is restored to a free state, and the spring is in a compressed state. The driving rod 813 drives the sliding ring 821 to move the movable shaft 5 upwards, meanwhile, the outer tooth portion 51 is gradually separated from the inner tooth portion 33, the sun wheel 6 is gradually matched with the planet wheel 312, when the movable shaft 5 moves to the second position, the positioning ball 8243 enters the second positioning hole 823 under the action of the spring to play a positioning role, at the moment, the outer tooth portion 51 is completely separated from the inner tooth portion 33, the sun wheel 6 is completely meshed with the planet wheel 312, and the gear shifting of the speed reducer from a high speed to a low speed is completed.

When the gear shift from low speed to high speed (i.e. from the second position to the first position) is required, the motor is stopped, the driving rod 813 is driven by hand to move downwards, so that the positioning ball 8243 is gradually moved out of the second positioning hole 823 by the external force and the sliding ring 821 is restored to the free state, and the spring is in a compressed state. The driving rod 813 drives the sliding ring 821 to move the movable shaft 5 downwards, meanwhile, the sun gear 6 is gradually separated from the planet gear 312, the external tooth portion 51 is gradually matched with the internal tooth portion 33, when the movable shaft 5 moves to the first position, the positioning ball 8243 enters the first positioning hole 822 under the action of the spring to play a positioning role, at the moment, the sun gear 6 is completely separated from the planet gear 312, the external tooth portion 51 is completely meshed with the internal tooth portion 33, and the gear shifting of the speed reducer from the low speed to the high speed is completed.

Need not to shut down for a long time or dismantle and change the reduction gear and can realize the speed governing of shifting, and compact structure, small, easy operation, the maintenance of being convenient for also can shift the operation fast under the complex environment, has very high practicality.

The above description is only a preferred embodiment of the present invention, and therefore should not be taken as limiting the scope of the invention, and the equivalent variations and modifications made in the claims and the description of the present invention should be included in the scope of the present invention.

Claims

1. The utility model provides a planetary gear reducer of shiftable gear which characterized in that: the planetary gear comprises a shell, an input shaft, a movable shaft, a sun gear, a planet carrier, a fixed gear ring and an output shaft, wherein the input shaft, the movable shaft, the sun gear, the planet carrier, the fixed gear ring and the output shaft are arranged in the shell and are coaxially arranged;

the planet carrier is fixedly connected with the output shaft, a plurality of planetary wheel mechanisms which are arranged in an array mode in the rotating direction of the planet carrier in a winding mode are arranged on the planet carrier, and the fixed gear ring is arranged outside the planetary wheel mechanisms in a winding mode and meshed with the planetary wheel mechanisms; the planet carrier is provided with a shaft hole arranged along the axial direction, one end of the shaft hole is provided with an inner tooth part which protrudes inwards, and the other end of the shaft hole is provided with a yielding space;

2. A shiftable planetary gear reducer according to claim 1, wherein: the planet wheel mechanism comprises wheel shafts and planet wheels, and the wheel shafts are circumferentially arrayed on the planet carrier around the rotation direction of the planet carrier; the planet gears are meshed with the fixed gear rings and are arranged on the wheel shafts in a one-to-one correspondence manner.

3. A shiftable planetary gear reducer according to claim 2, wherein: the planet carrier comprises a turntable, a connecting ring and a connecting piece, the turntable is connected with the tail end of the output shaft, and the wheel shaft is arranged on the turntable; the planet wheel is arranged between the connecting ring and the rotary table, and the internal tooth part is formed on the connecting ring; the connecting piece is connected between the rotary disc and the connecting ring.

4. A shiftable planetary gear reducer according to claim 1, wherein: the gear shifting mechanism can drive the movable shaft to move to a first position or a second position on the output shaft, and comprises a driving piece and a positioning piece, wherein the driving piece can drive the movable shaft to move back and forth on the output shaft; the positioning piece is arranged on the movable shaft and used for positioning a first position and a second position, and comprises a sliding ring, a first positioning hole, a second positioning hole and a positioning component, wherein the sliding ring is connected between the driving piece and the movable shaft and can be switched between the first position and the second position along with the driving piece; the first positioning hole and the second positioning hole are formed outwards from the inner wall of the shell, are distributed along the direction of the rotation axis and are respectively opposite to the positions of the sliding rings at the first position and the second position; the positioning component can respectively extend into the first positioning hole and the second positioning hole at the first position and the second position to play a positioning role.

5. A shiftable planetary gear reducer according to claim 4, wherein: the positioning assembly comprises a positioning groove, a positioning spring and a positioning ball; the positioning groove is formed inwards from the outer side surface of the sliding ring and can be respectively opposite to the first positioning hole and the second positioning hole when in a first position and a second position; the positioning spring is arranged in the positioning groove; the positioning ball is arranged in the positioning groove and can be embedded into the positioning groove under the action of the positioning spring.

6. A shiftable planetary gear reducer according to claim 5, wherein: the driving piece comprises a first bearing, a sleeve, a driving rod and a sliding groove, and the first bearing is sleeved between the sliding ring and the movable shaft and can move back and forth along with the sliding ring and the movable shaft; the sliding chute is formed on the shell to communicate the space inside and outside the shell; the sleeve is sleeved on the shell and used for sealing the sliding chute; the driving rod penetrates through the sleeve and the sliding groove in sequence and extends into the shell to be connected with the sliding ring, and the driving rod can move back and forth along the extending direction of the sliding groove and drive the movable shaft to move to a first position or a second position.

7. A shiftable planetary gear reducer according to claim 6, wherein: the movable shaft outside from the shaping of upwards caving in of bottom surface has first shaft shoulder, is provided with first spacing ring on the first shaft shoulder, first bearing medial surface joint is between first shaft shoulder and first spacing ring, the shaping of the inboard bottom surface of following of slip ring upwards caving in has the second shaft shoulder, is provided with the second spacing ring on the second shaft shoulder, first bearing lateral surface joint is between second shaft shoulder and second spacing ring.

8. A shiftable planetary gear reducer according to claim 1, wherein: the loose axle with through splined connection between the input shaft, the last shaping of loose axle has the first keyway that supplies the spline to pass, the second keyway that the last shaping of input shaft supplied the spline to pass, spline one end and second keyway fixed connection, the other end and first keyway sliding connection, make the loose axle keep and can follow the axis direction under the synchronous transmission state of input shaft and move about to primary importance or second place.

9. A shiftable planetary gear reducer according to claim 3, wherein: the connecting piece comprises a first screw hole, a second screw hole, a limiting sleeve and a fixing bolt, and the first screw hole penetrates through the connecting ring; the second screw hole is formed on the rotary disc and is opposite to the first screw hole; the limiting sleeve is connected between the rotary table and the connecting ring and enables the first screw hole to be communicated with the second screw hole; the fixing bolt sequentially penetrates through the first screw hole, the limiting sleeve and the second screw hole to fix the connecting ring on the rotary table, so that a space for accommodating the planet wheel is formed between the connecting ring and the rotary table.

10. A shiftable planetary gear reducer according to claim 1, wherein: the width of the outer teeth and the inner teeth is less than the distance from the first position to the second position.