GB2221278A

GB2221278A - Planetary gear system

Info

Publication number: GB2221278A
Application number: GB8913061A
Authority: GB
Inventors: Ganxu Zhou
Original assignee: HUNAN RESEARCH INST OF MACHINE
Current assignee: HUNAN RESEARCH INST OF MACHINE
Priority date: 1988-06-30
Filing date: 1989-06-07
Publication date: 1990-01-31
Anticipated expiration: 2009-06-07
Also published as: GB2221278B; CN1039091A; JPH0242232A; CN1018567B; GB8913061D0

Abstract

A planetary gear system comprises an input shaft (5), an output shaft (1) and at least one meshing gear-pair (Z1, Z2) connecting the input shaft (5) to the output shaft (1). One of the gears (Z2) of said gear-pair is eccentrically mounted relative to the input shaft (5). The system includes at least one crank member (2) having a first bearing end engaged with the eccentrically mounted gear (Z2) and a second bearing end, offset with respect to the first, which is engaged with either a further gear (Z3) or a fixed member (9, Figure 2). The system is provided with balancing means (6). <IMAGE>

Description

DESCRIPTION Planetary Gear Speed Reducer And Transaission Gear-box with Coaplex Minor Tooth-Difference This Invention relates to involute Rear planetray transaission aechanisa , and particularly relates to involute gear planetary transaission aechanis. and device with complex minor tooth-difference.

Patent applicatlons were filed with the Chinese Patetn Office with the titles Transaission Device of Planetary Gears with Coaplex Minor Tooth-difference" ( filed on April 1 , 1985 , Patent No. 85100376 ) and "Planetary Transalsslon itiechanisa and Device of Involute Gears with Coaplex Minor Tooth-dlfference" (filed on July 18 , 1987 , Applicaiton No. 87102061 ) by the saie inventor and applicant of this invention In the docuaents of the these patent applications descriptions were given on reduction gears comprising two Internal meshing Rear- pairs and transaission Rears comprising three or adore internal meshing Rear- pairs. However , they did not relate to reduction Rears comprising one internal lashing Rear- pair and transaisslon Rears comprising two internal meshing gear-pairs.

The obiective of this invention is to provide a planetary speed reducer with coaplex ainor tooth-difference. the transmisslon ratio of which is not only to be furnished by two internal aeshing gear-pairs , but , as a particular case, also by one Internal aeshing gear-pair.

Another important objective of this Invent Ion is to provide a planetary transalssion gear-box with complex minor tooth-difference having two internal meshing gear-pairs which can furnish two different transiission ratios.

A further iiportant objective of this invention is to eiploy a rolling planet wheel as the rotation-transmitting aechanisi between the planetary Rears.

The above- mentioned objectives are realized thus : The planetary Rear speed reducer and transaisslon Rear-box with coiplex minor tooth-difference of the present Invent Ion Includes rally a double-toggled crankshaft comprising an input shaft and an eccentric sleeve , Internal meshing gear-pair asseablles, planet wheel seat , rotatlon-transaitting iechanisa , an output shaft and a housing. The planet gear of each of the internal aeshing gear-pairs Is rotatably mounted on the crank axle of the crankshaft.The nodule , tooth difference and the eccentric distance of the respective crank axles of the two internal aeshing gear- pairs can be different and can also be equal. The Internal meshing gear-pairs are comprised of spur gears.

a. As is shown in Fig. 1 , the speed reducer Is constituted by two internal meshing gear- pairs the Internal gear Z of one of the gear-pairs Is stationary and aeshes with Rear Z ; the internal Rear Z of the other gearpair Is Integral with the power output shaft 1 and aeshes with Rear z ; the planet gears E and z are coupled through a rolling planet wheel 2.

b. As is shown in Flg.2 . the speed reducer Is forded by one internal meshing gear-pair : the internal gear Z is integral with the power output shaft I and meshes with Z, which is coupled with the stationary planet wheel seat 9 through a rolling planet wheel 2.

c. A speed reducer is forded by one Internal meshing gear-pair (not shown in drawings). the Internal gear Z Is stationary and Is In aesh with Z , the planet wheel seat 9 Is Integral with the power output shaft I.the gear Ze is coupled with the planet wheel seat 9 through the rolling planet wheel 2.

d. As is shown In Fig.3 , a transaission Rear-box Is formed by two Internal meshing gear- pairs: the planet Rears E and Z, are coupled with each other through the rolling planet wheel 2', a bearing Is aounted on the Journal of the riddle cylindrical section of the planet wheel 2' and Is supported by the planet wheel seat 9', the planet wheel seat 9' and the Internal gear Za' at the Input end are alternately held stationary. When the planet wheel seat 9' Is held stationary , L' is rotatable and a low transaission ratio Is obtained through the action of the planet gear z2 and the Internal Rear L which Is integral with the output shaft I ; when the Internal gear Z' is held statlonary,the planet wheel seat 9' Is rotatable. a high transalsslon ratio Is obtained through the action of Z, meshing with e' and E with Z, e.A bilateral balancer 6 (6', 6") designed on the three-point bilateral action concept is counted at the reiote end of the input shaft protruding Into the recess in the flange of the output shaft, as Is shown in FfRs. 1-3.

The said rolling planet wheel is a toggle link composed of three cylindrical sections. When the rolling planet wheel Is to be coupled with the two planet gears. rolling bearings are counted on the two cylindrical sections at the two ends , the said rolling bearings fit into evenly distributed holes on the center circles In the respective planet Rears , the diameters of the said center circles and the numbers of the said evenly distributed holes are equal.

When the rolling planet wheel is to be coupled with two planet gears and a planet wheel seat , rolling bearings are counted on all three cylindrical sections , the said rolling bearings fit into evenly distributed holes on the center circles in the respective planet gears and the planet wheel seat , the diameters of the said center circles and the nuabers of the said evenly distributed holes are equal.

The central cylindrical section of the said rolling planet wheel rotates about its own axis and at the saone tiie revolves around the center line of the speed reducer , and is therefore termed a "planet wheel"' since the ioving parts of the planet wheel are counted on rolling bearings , hence such a rotationtransittinR mechanism is teraed a "rolling planet wheel".

The above mentioned components constitute the basic constructlon of the planetary Rear transalsslon aechanlsn of involute gears with coiplex minor tooth- difference , the power input shaft of which can be coupled to a power Input gearbox to fora a series of planetary gear speed reducers or speed trans.ission units (also can be used as speed Increase units ) to meet the requireaents of varlous applications , they can be installed in horizontal, upright. Inverted and lateral positions, and the power output can be delivered by cylindrical shafts , end-surface jaws , Internally splined bores or singleor double-keywayed bores.

In the drawings: Fig. I is a schematic drawing showinR the working principle of the planetary Rear speed reducer with coiplex minor tooth-difference comprising two Internal meshing gear- pairs and a rolling planet wheel as the rotatlon-transalttlng eechanlsai Fig. 2 is a schematic drawing shoving the working prlnciple of the planetary Rear speed reducer with complex minor tooth-difference comprising one internal meshing, gear- palr and a rolling planet wheel as the rotation-transaitting mechanism;; Flg. 3 is a schematic drawing showing the working principle of the planetary gear speed transaission Rear-box with complex ainor tooth- difference comprising two Internal meshing gear-pairs and a rooling planet wheel as the rotation-transmitting mechanism; Fig. 4 is a constructlonal elevation of a signie stage planetary Rear speed reducer with complex minor tooth-difference Comprising two Internal meshing gear-pairs and a rolling planet wheel as the rotation-transalttlnR mechanism;; Fig. 5 Is a constructlonal elevatlon of a single stage planetary gear speed reducer with complex minor tooth-difference comprising one Internal meshing gear-pair and a rolling planet wheel as the rotation-transaitting echanlsa;; Fig. 6 is a constructlonal elevatlon of a planetary gear speed transaisslon gear-box capable of giving two transaission ratios with complex minor toothdifference comprising two internal meshing gear-pairs and a rolling planet wheel as the rotation-transaitting aechanlsa The characteristics of the present Invent ion will be described In detail In conjunction with the accompanying drawings. As Is shown In Fig. 1 , the crankshaft 5 has two crankaxles 4 and 3 , the Internal gear Z Is stationary, the planet Rear Z. is loose-sleeved to for1 a running fit on the journal of the crankaxle A and meshes with L . Another planet gear L Is loose-sleeved to fori a running fit on the Journal of the other crankaxle 3 and aeshes with the Internal Rear Z . The output shaft 1 is integral with the Internal Rear L and is coaxial with the crankshaft 5.The rotation-transmitting aechanlsa between the planet Rears I and I is the rolling planet wheel 2 , which coaprises a toggle link , on the cylindrical sect ions at the two ends of this toggle link are ounted rolling bearings which fit respectively into the evenly distributed holes in the planet Rears E and Z .The center circle of these evenly distributed holes In the planet gear L has a diaieter of D@ and the center circle of the evenly distrubuted holes In the planet gear Z has a diameter of D@ ; Dn and L6 should be made equal,also the nuibers of evenly distributed holes in both planet gears should be equal. In the recess on the inner face of the output shaft , a bilateral balancer 6 designed on the three- point bilateral action concept Is counted at the end of the crankshaft 5.The balancer 6 works in this ianner : suppose the distance between the centres of gravity of the balancer 6 and the assembly of Rear Z. and crankaxle 3 is S1 , and the distance between the centres of gravity of the asseibly of Rear Z. and crankaxle A and the assembly of gear L and crankaxle 3 is S , during operatlon , the balancer 6 produces a centrifugal force F, . the assaebly of gear I and crankaxle 3 produces a centrifugal force F2 , and the assembly of gear I and crankaxle 4 produces a centrifugal force F, . (forces are not shown in drawings. ) .In order to transmitting stably and smoothly , the following two formulas rust be satisfied stimultaneously. i.e.

F2 = F1 + F2 and F1XSI = F,XSI To select the optimal coabinatlon of Rears for the specified tranmission ratio under conditions of ratlonal structural design , spur gears are used throughout for the Internal aeshing gear-pairs of the planetary gear speed reducer with complex minor tooth-difference of the present invention , the design rules are: Z1 -Z ; > Z1 -Z In #@M , and an > aM , wherein Z1 , Z , Z3 , Z4 denote the nuabers of teeth of the respective gears; #12 denotes the nodule of gears I and I ; aX denotes the nodule of gears Z and Z ap denotes the eccentric distance of the crank axle at the gear-pair Z, and Z2 ; aX denotes the eccentric distance of the crank axle at the gear-pair Z and Z.

Also the eccentric distance between the cylindrical journals at the ends of the toggle link of the rolling planet wheel 2 should equal the sui of the eccentric distances between the crank axles supporting the two gear-pairs , I.

e , It should equal ( Bn + a24 ) al The above descrlbed mechanism works In this ianner : Rotative motion Is introduced Into the reducer froi crankshaft 5 , the planet Rear Z rotates about Its own axis and revolves around the Internal gear Z, , Its rotating lotion is In turn transaitted to the planet Rear L through the rotationtransaitting aechanlsa, I.e. the rolling planet wheel 2. The joint action of Z and the crankshaft 5 lakes Z2 to rotate about its own axis and revolve around the Internal gear Z, , thus the reduced rotation speed Is translitted through the meshing internal Rear Z, to the output shaft 1.

Fig. 2 shows a planetary Rear speed reducer of low transMission ratio with one internal meshing gear-pair , it differs froi that shown in Fig. I In that the Rears Z and Z,, are not used , they are replaced by a planet wheel seat 9 (I.e.

fixed ring ) . On this planet wheel seat 9 n evenly distributed holes are drilled , the diameter of their center circles Is equal to the diameter of the center circle of the evenly distributed holes on Rear L , i.e., , Db = . The two journals of the planet wheel engage respectively with the evenly distributed and equal in number holes In the planet gear Z2 and In the planet wheel seat 9. Slnce the planet Rear Z, is omitted , a balance weight 8 Is placed on the axle where Z, was originally installed. This balance weight 8 is latched with the planet gear asseably Z, and the bilateral balancer 6' to constitute a three-point bilateral balancing system.

This planetry Rear speed reducer works thus : Rotatlve lotion is Introduced Into this reducer through the crankshaft 5 , as one Journal of the rolling planet wheel 2 Is engaged In the evenly distributed hole In the planet wheel seat 9, the rolling planet wheel 2 can only rotate about Its own axis and cannot revolve around the axis of the Rearbox.The planet Rear L , which is under the action of the crankshaft 5 and the rolling planet wheel 2, can only revolve in its plane around the internal gear Z14 which Is in engagement with Z, As there exists a difference In the number of teeth In Z1 and Z, , the planet Rear Z2 drlves the Internal gear Z1 to rotate at a reduced speed , and this rotation Is transmitted to the driven object through the output shaft.

The planetary Rear speed transrlssion gear-box with complex minor toothdifference shown in Fig. 3 differs itself in principle froi that shown in Fig.

1 in that it has a floating planet wheel seat 9' between the two planet gears.

The evenly distributed holes In the planet wheel seat 9' slip over the riddle journal of the rolling planet vheel. The diameters of the center circles of the evenly distributed holes In the planet gears D22, D and that In the planet wheel seat D20 should be equal , i.e. i.e. . =D22 =DD24 . The numbers of the evenly distributed holes should also be equal. The planet wheel seat 9' and the internal gear Z' are alternately held stationary or are left floating.

The working principle of this speed transMission device Is as follows: Rotative lotion Is Introduced into this device through the input shaft 5; when the planet wheel seat 9' is held stationary and the Internal Rear L' is floating, Z3 and Z.' are rotating under no load,and the planet gear Z2 revolves in Its plane under the joint action of the rolling planet wheel 2' and the crankshaft 5.As Z2 is in engagerent with the internal gear Z1 and owing to the difference in the number of teeth, I will drive Zt to rotate at a reduced speed with a low transmission i,. When the internal gear L' is held stationary and the planet wheel seat 9' Is floating,the planet gear I rotates about Its own axis and also revolves around the Internal gear Z' under the joint action of the crankshaft 5 and the stationary Internal Rear Z' .The rotative lotion Is transmitted through the rolling planet wheel 2' to the planet wheel seat 9' and the planet Rear Z2, the planet wheel seat 9' rotates together with the rolling planet wheel 2', whilst the planet Rear I rotates as well as revolves under the joint action of the rolling planet wheel 2' and the crankshaft 5. As the planet gear Z2 and the internal gear 24 are in engagement and the latter is solidly coupled with the output shaft , a reduced rotative speed will be transmitted to the driven object with a high transiission ratio i2 . The range of ii /12 can be selected according to the requireients of application.

The advantages of the devices of the present invention are obvious: 1.The transmission ratio attainable with the present invent Ion is wide-ranged and can have very dense divisions, which cannot be attained on any other types of reducer products. The translission ratio of a single stage ranges fror 14 to 125 divided In 39 steps ; speed reducer having a series-connected expansion stage at their Input end can have transmission ratlos ranging frol 71 to 2 ,000 divided in 58 steps ; speed reducers connected In series can have transilsslon ratios ranging froM 224 to 16 ,000 divided in 74 steps ; optional transMission ratios can ranRe froM 17,888 to 4,000,000.

2. The loading capacity of the speed reducer and translission Rear-box Is high.

The serial products have center line heights ranging froM 8lM to 560## covering 16 product-tyPes , the torque transaitted ranges froM 60 to 122 ,S N.#, power transaitted ranges froM e.e6 KW to 300 KW.

3. The transaission efficiency of the speed reducer and transMission gear-box is high. With a rigorous desiRn of optilized parameters , the engageMent efficiency of the gears can reach 99% ; also , as rolling bearings are used throughout In the rotatlon- translitting lechanisls , a very high combined translission efficiency can be attained.

A. The linear speed of the gear teeth of the speed reducer and transalssion Rear-box is usually kept under I l/sec , also a unique bilateral balancer incorporating the three-point bilateral balancing design is used, hence it has stable and sMooth operation and the noise level is in the range of 6 to 80 dB.

5. The speed reducer and transMission Rear-box is designed with precisely selected constructional parameters and heat balance considerations , with the application of special technology and rolling bearings for all rotation transitting MechanisMs , hence It has the features of long service life and high reliability.

6. The speed reducer and transMission Rear-box of the present Invention has a wide ranRe product-types and extensive adaptiblllty for application , they are of highly standardized , serialized and interchanReable Modular construct Ion.

The products designed cover a range of 16 series of 44 ,832 varieties of rigorous construction offering convenlence for selection. And It has been designed for use In constructlon-cachinery the driving speed reducer , rotary table speed reducer4 holster speed reducer, winch speed reducer4 motor-driven roller speed reducer4 and for use In boiler the speed reducer and transMission Rear-box etc. and several varieties for special purposes.

7. The present invention can use involute spur gear assemblies without tooth correction so that the complex calculations ay be avoided. The pressure angle of the meshing gears is sMall so that the radial load of the bearings will be reduced.

The characteristics of the present invention can best be understood through the description of exaMples of eMbodilents. However , these exaMples do not in any way lapse liMitations to the scope of the Invent Ion.

The constructlon of a planetary gear speed reducer eMbodying the singly-stage.

double-axle design of Fig. I fs shown in FiR, 4 The housing 15 of the reducer has on its left two cascaded recesses to receive respectively the bearings lA and 16 , the two stepped journals on the output shaft 11 fit respectively in the inner bores of the bearings 14 and 16, forMing transition fits. The end cover 13 is secured onto the housing 15 by screws , pressing on the bearing 14 axially. In the end cover 13 Is fitted a sealing ring which presses on the outer circuaference of the stopper ring 12 gripping on the output shaft 11.

The stopper ring 12 bears on the inner ring of the bearing 14 to prevent the latter froM loving axially. The rlght end of the output shaft Is in the forM of a flange, the internal Rear 18 Is secured to the flange by rivets; saddle keys are also fitted between these two coMponents to allow larRe torques to be transMitted. A recess is Made in the central part of the flange of the output shaft , which receives a bearing 48. The journal at one end of the Input shaft 31 fits into the Inner bore of the bearing 48; another bearing 32 Is fitted on the journal at the other end of the input shaft. The bearing 32 is received In the bore of the bearing seat 28 , the latter Is secured to the housing 15 by screws.The end cover 29 Is secured to the bearing seat 28 by screws and bears on the bearing 32. In the end cover 29 Is fitted a sealing rlng, which presses on the stopper ring 3 On the input shaft 31 is fitted an eccentric sleeve 33 which serves as crank axles. This eccentric sleeve has two sections , on each of which is respectively fitted the bearing 38 , 25 (these eccentric sections correspond to the crank axles depicted in Fig. 1 ), the eccentric distances of these crank axles are respectively au and au .On bearing 38 is Mounted the planet gear 2e , and on bearing 25 is Mounted the planet gear 24 The Internal gear 23 ( the gear L In Fig. I ) is secured to the housing 15 by cylindrical dowel pins ( not shown in the drawing ). The bearing seat 28 bears on the internal Rear 23 , and the planet Rears 2 and 24 respectively Mesh with the internal gears 18 and 23. On the right side of the bearing 25 a retainer collar 26 liMits the axial MoveMent of the bearing , and retainer collars 39, 27 are also located at the two ends of the eccentric sleeve 33 to keep the sleeve in its axial position.A bilateral balancer Al Is fixed at the end of the input shaft 31 and reaches Into the recess In the flanRe of the output shaft to keep the rotatinR parts of the transMission aechanlsa in balance In both directlons and to Insure sMooth operation. The input shaft 31 and the eccentric sleeve 33 are coupled by a single key 35.Between the planet gears 2 and 24 is the rolling planet wheel 22 , which is a toggle link and rolling bearings are Mounted on the journals at both ends of this toggle link and are respectively Inserted into the evenly distributed holes in the planet gears 2e and 24 Hoisting rlng 21 , oiling hole and vent plug 19 , oil drain hole and plug 36 and oil level window 37 are also located on the housing 15. The said bearings 16, 32, 18 can be annular ball bearings or annular short cylindrical roller bearings . For an upright speed reducer the bearing 48 should be chanRed into a rolling bearing capable of taking up axial load.The said bearing 14 can be an annular spherical roller bearing , or It can be a self aligning double row spherical roller bearing. The said bearings used on the rolling planet wheel 22 can be annular spherical roller bearings , short cylindrical roller bearings , or self-aligning double row spherical roller bearings.

Fig. 5 shows a horizontal double-axle speed reducer , It is a special exaiple of that shown in Fig. 4 , the difference lies in that the gears 24 and 23 are omitted and a planet wheel seat 48 Is Included Instead , which is secured to the housing 15 by cylindricl dowel pins (not shown In the drawing) The planet gear 2 is coupled to the planet wheel seat 48 through the rolling planet wheel 22 , and speed reducer Is effected by only one Internal meshing Rear pa Ir. The counter weight 43 shown In the drawing has an eccentric distance of a , this balance weight 43 Matches with the planet gear asseMbly and the bilateral balancer to constitute the bilateral balancing system. Other features are the sase as described In Fig. A.

Fig. 6 Is a horizontal double-axle transMission planetary Rear-box with complex Minor tooth-difference, It differs with that shown In Fig. A in that It has In additlon a floating planet wheel seat 48' A rolling bearing 44 Is Mounted on the Middle journal of the toggle link of the rolling planet wheel 22'. On the outer circuMference of the planet wheel seat 48' there are n straight grooves.

the planet wheel seat 48' Is Maintaining a certain clearance with the Inner bore of the housing 15' The internal gear 23' has n round recesses on its outer circumference and is in running fit with the inner bore of the housing 15'.The cylindrical pins AS and 47 shown In the drawing are actuated by the actuator 46 to slide up and down. the Mode of operatlon is thus: The hand lever rotates an internal Rear ( not shown in the drawIng ) which drives two external gears, one of which Is located above the cylindrical pin 45 , the other above the cylindrical pin 47; the external gears are connected with the cyllndrical pins 45 and 47 respectively through a right hand screw and a left hand screw.When the Internal gear Is rotated , it sets the external gears to rotate , and the cylindrical pins 45 and 47 wlll slIde In opposite directions under the action of the right and left handed screw threads. When the cylindrical pin 45 slides downwards and engages with a straight groove on the outer circuMference of the planet wheel seat 48', the latter Is arrested froM rotating4 whilst the planet gear 23' Is floating , and the gear- pair 2 and 18 will effect a low transMission ratio Ii .When the cylindrical pin 47 slides downwards to engage with a round recess In the outer cIrcuMference of the Internal Rear 23', the cylindrical pin 45 will siMultaneously slide upwards to disenRaRe froM the straight groove on the outer clcuaference of the planet wheel seat , thus the internal gear 23' will be arrested and the planet wheel seat 48' will be floating, the gears 23', 24, 28, 18 will work to give a high transMission ratio 1z . A change of rotatlon speed can be attalned through the alternate fixing and floating of the planet wheel seat 48' and the Internal gear 23'. There can be various devlces to actuate the fixing and floating of the planet wheel seat 48' and the internal Rear 23', such as belt type, wedge operated band brake, or it can be electrically or hydraulically controlled , these devIces will not be discussed In detall here. Other features are the sa.e as described In Flff. A.

Claims

1. A planetary gear system with complex minor tooth-difference comprising: an input shaft; an output shaft; at least one meshing gear-pair connecting the input shaft to the output shaft, one of the gears of said gear-pair being eccentrically mounted relative to the input shaft; and, at least one rolling planet wheel having a first bearing end engaged with the eccentrically mounted gear and a second bearing end, offset with respect to the first, engaged with either a further gear or a fixed member.

2. A system according to claim 1, comprising a bilateral balancer mounted towards the end of the input shaft which is adjacent to the output shaft.

3. A speed reducer comprising a system according to claim 1 or claim 2, having two internal meshing gear-pairs, wherein: the internal gear of the first gear-pair is stationary and meshes with a first corresponding planet gear which is rotatably mounted on the input shaft; and, the internal gear of the second gear-pair is integral with or rigidly attached to the output shaft and meshes with a second corresponding planet gear which is rotatably mounted on the input shaft; the first and second planet gears being coupled through the rolling planet wheel.

4. A speed reducer comprising a system according to claim 1 or claim 2, having one internally meshing gear-pair and a stationary planet wheel seat, wherein: the internal gear is integral with or rigidly attached to the output shaft and meshes with a corresponding planet gear; and, the planet gear is coupled with the stationary planet wheel seat through the rolling planet wheel and is rotatably mounted on the input shaft.

5. A speed reducer comprising a system according to claim 1 or claim 2, having one internally meshing gear-pair, and a planet wheel seat which is integral with or rigidly attached to the output shaft; wherein: the internal gear is stationary and is meshed with the corresponding planet gear; and, the planet gear is coupled with the planet wheel seat through the rolling planet wheel and being rotatably mounted on the input shaft.

6. A speed reducer according to either of claim 4 or claim 5 when dependent on claim 2, comprising a second bilateral balancer mounted on the input shaft towards the input end from the first balancer.

7. A transmission gear-box comprising a system according to claim 1 or claim 2 having a first meshing gear-pair at the input end, and a second meshing gear-pair at the output end; the planet gears of the first and second meshing gear-pairs being coupled with each other through the rolling planet wheel, each planet gear being rotatably mounted on the input shaft; the internal gear of the first gear-pair and a planet wheel seat being selectively alternately holdable stationary; the internal gear of the first gear-pair being rotatable when the planet wheel seat is held stationary, a low transmission ratio being obtained through the action of the planet and the internal gears of the second gear-pair, the internal gear of the second gear-pair being integral with or rigidly attached to the output shaft;; the planet wheel seat being rotatable when the internal gear is held stationary, a high transmission ratio being obtained through the action of the planet gear of the first gear-pair meshing with the internal gear of the first gear-pair the action of the rolling planet wheel and the planet seat, and the action of the planet gear of the second gear-pair meshing with the planet gear of the second gear-pair.

8. A system according to any of the preceding claims, wherein the coupling between a planet gear and a rolling planet wheel is by means of at least one toggle link.

9. A system according to claim 8 when dependent on claim 3, wherein: the or each toggle link comprises two cylindrical sections, rolling bearings being mounted on each section, the rolling bearings being received by evenly distributed apertures provided in each planet gear at a constant radius.

10. A system according to claim 8 when dependent on claim 7, wherein: the or each toggle link comprises three cylindrical sections, rolling bearings being mounted on each section, the rolling bearings being received by evenly distributed apertures provided in each planet gear and the rolling planet wheel at constant radii.

11. A system according to any of the preceding claims, wherein: the input shaft is supported at one end by a bearing in a recess in the output shaft.

12. A system according to any of the preceding claims, wherein: an eccentric sleeve with at least two crank axles is mounted on the input shaft.

13. A system according to claim 4, wherein the stationary planet wheel seat is secured to a housing by means of at least one cylindrical dowel pin.

14. A system according to claim 7, wherein; the outer circumference of the planet wheel seat is provided with equally-spaced recesses; and, the outer circumference of the internal gear of the first gear-pair is provided with equally-spaced recesses; the system further comprising an actuator which selectively engages a recess in the planet wheel so as to hold stationary the planet wheel, or a recess in the internal gear of the first gear-pair so as to hold the internal gear stationary.

15.A planetary Rear speed reducer and transMIssion gear-box with complex Minor tooth- difference includinR MaInly a double-toggled crankshaft comprising an input shaft and an eccentric sleeve , Internal Meshing gear-pair asseMblies4 planet wheel seat , rotation-transmitting MechanisM , an output shaft and a housing ; the planet gear of each of the Internal Meshing gear-pairs Is rotatably Mounted on the crank axle of the crankshaft ; the Module , tooth difference and the eccentric distance of the respective crank axles of the two internal Meshing gear- paIrs can be different and can also be equal ; the internal Meshing gear-pairs are comprised of spur gears, wherein: a. the speed reducer Is constituted by two internal Meshing Gear-pair 4 the internal Rear Z4 of one of the Rear-palrs is stationary and Meshes with Rear I ; the Internal gear Zl of the other gear-pair is integral with the power output shaft 1 and Meshes with gear I ; the planet gears Za and Z are coupled through a rolling planet wheel 2; b. the speed reducer Is forMed by one Internal Meshing gear-pair, the Internal gear Z1 Is integral with the power output shaft 1 and Meshes with Z which is coupled with the stationary planet wheel seat 9 through a rolling planet wheel 2; C. the speed reducer Is forMed by one Internal Meshing gear-pa Ir4 the Internal Rear Z4 Is stationary and is in Mesh with Z , the planet wheel seat 9 Is Integral with the power output shaft 1, the gear Z is coupled with the planet wheel seat 9 through the rolling planet wheel 2; d. the transMission gear-box Is forMed by two internal Meshing Rear-palrs, the planet gears I and 24 are coupled with each other through the rolling planet wheel 2', a bearing Is Mounted on the journal of the MIddle cylindrical section of the planet wheel 2' and Is supported by the Dlanet wheel seat 9'; the planet wheel seat 9' and the Internal Rear Z' at the input end are alternately held stationary ; when the planet wheel seat 9' Is held statlonary, Z' is rotatable and a low transiisslon ratio Is obtained through the action of the planet gear L and the Internal gear Z, which Is integral with the output shaft 1; when the internal gear L' is held statlonary, the planet wheel seat 9'is rotatable4 a high transMission ratio Is obtained through the action of z Meshing with Z' and 24 with Z1 ; e. a bilateral balancer 6 designed on the three-point bilateral action concept Is Mounted at the reMote end of the input shaft protruding into the recess In the flange of the output shaft.

16.A planetary Rear speed reducer and transMission Rear-box with complex Minor tooth- difference according to ClaiM 15, wherein the rotatlon-transalttlnR MechanisM , i.e. the rolling planet wheel is a toggle link coMposed of three cylindrical sections ; when the rolling planet wheel is to be coupled with the two planet gears, rolling bearings are Mounted on the two cylindrical sections at the two ends , the said rolling bearings fit Into evenly distributed holes on the center circles in the respective planet gears , the diaMeters of the center circles and the nuMbers of evenly distributed holes are equal ; when the rolling planet wheel Is to be coupled with the two planet gears and the planet wheel seat , rolling bearings are punted on all three cylindrical sections , the said rolling bearings fit Into evenly distributed holes on the center circles In the respective planet gears and the planet wheel seat , the diameters of the said center circles and the nuMbers of the said evenly distributed holes are equal.

17. A planetary Rear speed reducer with coMplex Minor tooth-difference of a single-stage, double-axle deslRn coMprising Mainly a housing, a crankshft, two Internal Meshing gear- pairs and a rolling planet wheel , wherein the output shaft 11 Is supported In the housing 15 through a bearing, the Internal gear 18 is integral with the output shaft 11 , an eccentric sleeve 33 with two crank axles Is Mounted on the input shaft 31, this input shaft 31 Is supported at one end in a recess in the output shaft 11 through a bearing 48 and at the other end by a bearing 32 installed In a bearing seat 28 In the housing 15 ; the planetary Rears 2 and 24 are Mounted on the two crank axles of the eccentric sleeve through bearings 38 and 25; a retaIner collar 26 is located at the rIght side of the bearing 25 to prevent the axial MoveMent of the bearing ; gear 24 aeshes wIth the Internal gear 23, gear 2e Meshes with the Internal Rear 18, the Rears 24 and 2 are coupled through a rolling planet wheel 22; rolling bearings are counted on the cylindrical sections at the ends of the toggle link of the rolling planet wheel 22 ; a bilateral balancer Al is fixed at the end of the Input shaft 31 and protrudes Into recess in the end of the output shaft 11.

18. A planetary gear speed reducer with coMplex Minor tooth-difference of a horizontal , single-stage , double-axle design comprising Mainly a housing , a crankshaft , one internal Meshing Rear-palr a planet wheel seat and a rolling planet wheel , wherein the output shaft 11 is supported in the housing 15 by a bearing , the Internal gear 18 Is integral wIth the output shaft 11 , an eccentric sleeve 33' with only one crank axle and a balancing weIght 43 are Mounted on the Input shaft 31; a bilateral balancer 41' is fixed at the end of the Input shaft 31 and protrudes Into a recess In the end of the output shaft 11; the Input shaft 31 Is supported at one end In a recess in the output shaft 11 through a bearing A9 and at the other end by a bearing 32 Installed In a bearing seat 28 in the housing 15; a planet Rear 2e Is Mounted on the crank axle of the eccentric sleeve 33' through a bearing 38; the planet wheel seat 48 is secured on the housinR 15 by cylindrical dowel pins ; the Rear 2e Meshes with the internal gear 18 and In coupled with the planet wheel seat 48 through the rolling planet wheel 22, rolling bearings are Mounted on the cylindrical sections at the ends of the toggle link of the rolling planet wheel.

19. A planetary gear speed transMission gear-box with coMplex Minor tooth difference coMprisIng Mainly a housing , a crankshaft , two Internal meshing Rear-palrs , a planet wheel seat , a rolling planet wheel , wherein the output shaft 11 is supported in the houslnR 15' through a bearing , the Internal Rear 18 Is integral with the output shaft 11, an eccentric sleeve 33 with two crank axles Is mounted on the Input shaft 31, this Input shaft 31 Is supported at one end in a recess in the output shaft 11 through a bearing 18 and at the other end by a bearing 32 installed In a bearing seat 28 in the housing IS';; a bilateral balancer 41" Is fixed at the end of the Input shaft 31 and protrudes into a recess In the end of the output shaft 11 ; a retalner collar 26 Is located at the rlRht side of the bearing 25 to prevent the axial movement of the bearing ; the planet gear 24 Meshes with the internal gear 23', the planet gear 2e Meshes with the internal gear 18 , the Rears 24 and 20 are coupled through a rolling planet wheel 22', a rolling bearing AA Is Mounted on the riddle cylindrical section of the toggle link of the rolling planet wheel 22' and Is received In the evenly distributed holes In the planet wheel seat 48';; on the outer clrcuiference of the planet wheel seat 48' there are equallyspaced stralRht grooves , the planet wheel seat 48' Is aalntalnlng a certain clearance with the inner bore of the housing 15', and on the outer circuMference of the internal Rear 23' there are equally-spaced round recesses.

these Rrooves and recesses recelve respectively the cylindrical dowel pins AS and 47 , the actuator 46 controls the cylindrical pins 45 and 47 and Inserts the alternately into the Rroove or recess to arrest alternately the planet wheel seat 48' or the Internal gear 23', holding one of them stationary and leaving the other floating: when the planet wheel 48' Is arrested, the internal gear 23' becoMes floating , the Rear- palr 18 and 2e vill effect a low transmission ratio I1 ; when the Internal gear 23' Is arrested , the planet wheel seat 48' becoMes floating , the Rears 18, 28, 23', 24 will work to Rlve a high transMission ratio I:

20. A planetary gear system substantially as described with reference to any of Figures 1 and 4, Figures 2 and 5, or Figures 2 and 6.