Abstract:
The invention relates to a continuously variable transmission with side speed regulating lead screw, and it comprises: a housing, a driving flat disc system, a power input system, a middle flat disc system, a power output system, a compaction system, a speed regulating ratio system of the middle flat disc, and serial and parallel structures. Since the previously most successful continuously variable transmission is the CVT continuously variable transmission, such continuously variable transmission transmits power depending on the conical disc and steel belt, and the limitation of the continuously variable transmission restrains the extensive application of such continuously variable transmission, whereas the continuously variable transmission of the invention transmits power depending on the mutual compaction between the driving flat disc and the middle flat disc as well as between the middle flat disc and the driven flat disc. The invention aims to solve the problem of too small transmission torque existing in previous continuously variable transmissions, and it realizes the objective of regulating the speed ratio by the movement of the middle flat disc up and down.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention belongs to the field of continuously variable transmission. 
       BACKGROUND OF THE INVENTION 
       [0002]    Since the previously most successful continuously variable transmission is the CVT continuously variable transmission, such continuously variable transmission transmits power depending on the conical disc and steel belt, and the limitation of the continuously variable transmission restrains the extensive application of such continuously variable transmission, whereas the continuously variable transmission of the invention transmits power depending on the mutual compaction between the driving flat disc and the middle flat disc as well as between the middle flat disc and the driven flat disc. 
       SUMMARY OF THE INVENTION 
       [0003]    The invention aims to solve the problem of low mechanical efficiency existing in previous continuously variable transmission, the driving flat disc transmits the power to the middle flat disc through friction, the middle flat disc also transmits the power to the fixed driven flat disc and the sliding driven flat disc through friction, the power is transmitted to the output shaft through the driven flat discs, and the power is transmitted to the transmission by the output shaft. 
         [0004]    The speed regulating lead screw side continuously variable transmission comprises a housing, a driving flat disc system, a middle flat disc system, a power output system, a power input system, a speed regulating ratio system of the middle flat disc, a compaction system, serial and parallel structures, and the structural system of input shaft gear, intermediate gear of the driving flat disc and driving flat disc gear. 
         [0005]    Driving flat disc system: A pair of driving flat discs are matched with the driving flat disc gear through the driving flat disc keys and tightened by driving flat disc nuts, the bracket beams of the driving flat discs are arranged both the half bracket I of the driving flat disc and the half bracket II of the driving flat disc, the driving flat disc mandrel I is arranged in the middle of the bracket beam of the driving flat disc on the half bracket Li of the driving flat disc, the driving flat disc mandrel II is arranged in the middle of the bracket beam of the driving flat disc on the half bracket II of the driving flat disc, the half bracket I of the driving flat disc and the half bracket II of the driving flat disc are tightened and fixed by the mandrel bolt of the driving flat disc and the bracket bolt of the driving flat disc, and the driving flat discs are in running fit with the driving flat disc mandrel I and the driving flat disc mandrel II through the shaft. The lowest points of the bracket beams of the driving flat discs are lower than the plane of the driving flat discs. 
         [0006]    Power input system: In the structure of three middle flat discs in parallel, the schemes for the structural system of input shaft gear, intermediate gear of the driving flat disc and driving flat disc gear: 1. The input shaft gear is matched with one driving flat disc gear, and each pair of neighboring driving flat disc gears are matched with the same intermediate gear of the driving flat disc; 2. Each pair of neighboring driving flat disc gears are matched with the same intermediate gear of the driving flat disc, and the input shaft gear transmits power to each driving flat disc gear through the intermediate gear of the driving flat disc. 3. The input shaft gear transmits the power to two driving flat disc gears simultaneously, and one of the driving flat disc gears then transmits the power to the other driving flat disc gear through the intermediate gear of the driving flat disc. This kind of continuously variable transmission has the intermediate gear of the driving flat discs which can be matched with two driving flat disc gears, respectively, and the intermediate gear of the driving flat disc can be matched with the input shaft gear at the same time of matching with one driving flat disc gear. Power output system: There are driven flat disc grooves on the driven flat discs (including the fixed driven flat disc, the middle driven flat disc and the sliding driven flat disc), the output shaft passes through the center hole of the fixed driven flat disc, the fixed driven flat disc is fixed and connected with the output shaft, the sliding driven flat disc and the output shaft can relatively slide but can&#39;t relatively rotate, the output shaft passes through the center hole of the sliding driven flat disc, the sliding driven flat disc is fixed and connected with the hydraulic cylinder block, and the power is transmitted out of the transmission by the output shaft. 
         [0007]    Middle flat disc system: The lead screw nut of the middle flat disc on one part of the middle flat disc bracket is matched with the lead screw of the middle flat disc, the other part of the middle flat disc bracket is matched with the middle flat disc through the middle flat disc bearing, the lead screw of the middle flat disc is arranged on the side of the middle flat disc, the lead screw nut of the middle flat disc is integrated or fixed and connected with the middle flat disc bracket, and the middle flat disc works between the driving flat discs and the driven flat discs (including the fixed driven flat disc, the sliding driven flat disc and the middle driven flat disc). The lead screw of the middle flat disc can be sliding lead screw, rolling lead screw (including ball lead screw and roller lead screw) and hydrostatic lead screw; the matched lead screw nut of the middle flat disc can be sliding nut, rolling nut (including ball nut and roller nut) and hydrostatic nut. 
         [0008]    Forward and reverse conversions: The forward and reverse conversions of the continuously variable transmission shall be completed by the middle flat disc spanning from one side of the bracket beam of the driving flat disc to the other side of the bracket beam of the driving flat disc, namely, along with the rotation of the lead screw of the middle flat disc, the middle flat disc is moved to the bracket beam of the driving flat disc, one end of the middle flat disc continues to move along the bevel of the bracket beam of the driving flat disc, it continues to move after reaching the top of the bracket beam of the driving flat disc, and the other end of the middle flat disc continues to move along the bevel of the driven flat disc grooves of the driven flat discs (including the fixed driven flat disc, the sliding driven flat disc and the middle driven flat disc), so that the middle flat disc can reach the other side of the bracket beam of the driving flat disc. Owing to the existence of the driven flat disc grooves, the other end of the middle flat disc can move in the driven flat disc grooves. 1. When the driven flat disc grooves are deep enough, as the middle flat disc gets across the driven flat disc grooves, the compaction system is decompressed, and the middle flat disc can also span over the bracket beam of the driving flat disc without moving the sliding driven flat disc; 2. When the driven flat disc grooves are not deep enough, as the middle flat disc gets across the driven flat disc grooves, the compaction system is decompressed, and the middle flat disc can span over the bracket beam of the driving flat disc only when the sliding driven flat disc is moved towards the compaction system for a certain distance, but the moving distance of the sliding driven flat disc shall be less than that when there is no sliding driven flat disc groove on the sliding driven flat disc, the continuously variable transmission can be made into smaller size, and the cross section of the bracket beam of the driving flat disc can be made into bigger area. This kind of transmission can use the forward function but not use the reverse function. 
         [0009]    Compaction system: 1. The hydraulic compaction system comprises a hydraulic lever bracket which is fixed and connected with the output shaft, and when the hydraulic cylinder is compressed, one end of the hydraulic lever pushes against the sliding driven flat disc: one end of the hydraulic lever is contacted with the sliding driven flat disc through the hydraulic lever block; the hole in the middle of the hydraulic lever is hinged with the hydraulic lever bracket, and the hydraulic plate pulls the other end of the hydraulic lever; the hole at the other end of the hydraulic lever can be hinged with one end of the hinge of the hydraulic lever, and the other end of the hinge of the hydraulic lever can be hinged with the hinging base of the hydraulic lever, and the hinging base of the hydraulic lever is fixed on the hydraulic plate;  t he output shaft passes through the center hole of the hydraulic plate, and the hydraulic plate can slide on the output shaft relative to it. 2. Spring compaction system: One end of the strong spring pushes against the sliding driven flat disc, the other end pushes against the snap ring on the output shaft, and the snap ring on the output shaft is fixed and connected with the output shaft. 
         [0010]    The compaction system is not limited to the above two manners. 
         [0011]    Speed regulating ratio system of the middle flat disc: It is specified that the speed ratio is obtained by dividing the absolute value of input shaft speed by the absolute value of output shaft speed, the speed regulating ratio system of each middle flat disc: the lead screw for the bearing seat of the middle flat disc is fixed and connected with the housing, one end of the lead screw of the middle flat disc is installed on the lead screw for the bearing seat of the middle flat disc through the bearing, the other end of the lead screw of the middle flat disc is installed on the housing through the bearing, the threaded part of the lead screw of the middle flat disc is matched with the lead screw nut of the middle flat disc on the middle flat disc bracket, the lead screw nut of the middle flat disc is fixed and connected or integrated with the middle flat disc bracket, and along with the rotation of the lead screw of the middle flat disc, the lead screw nut of the middle flat disc drives the middle flat disc bracket and the middle flat disc to move back and forth along with the axis of the lead screw of the middle flat disc to realize the process of speed regulating ratio for the middle flat disc. The lead screw gear of the middle flat disc is fixed on the lead screw of the middle flat disc, the lead screw gear of the middle flat disc can be a worm gear, and the lead screw gear of the middle flat disc is matched with the regulating shaft gear of the middle flat disc on the regulating shaft of the middle flat disc; the regulating shaft gear of the middle flat disc can be a worm, the regulating shaft gear of the middle flat disc is fixed and connected with the regulating shaft of the middle flat disc, the regulating shaft of the middle flat disc is arranged vertical to the axis of the lead screw of the middle flat disc, the regulating shaft of the middle flat disc is arranged in parallel with the output shaft, and the speed regulating pinion of the middle flat disc on the regulating shaft of the middle flat disc is fixed and connected with the regulating shaft of the middle flat disc. 
         [0012]    Position 1 of the regulating shaft end of the middle flat disc: The regulating shaft end of the middle flat disc is arranged on one speed regulating pinion of the middle flat disc; 
         [0013]    Position 2 of the regulating shaft end of the middle flat disc: The regulating shaft end of the middle flat disc is separately matched with the gear at the regulating shaft end of the middle flat disc, and the regulating shaft end of the middle flat disc is matched with the speed regulating gearwheel of the middle flat disc. 
         [0014]    The speed regulating pinion of the middle flat disc of the speed regulating ratio system of each middle flat disc is matched with the same speed regulating gearwheel of the middle flat disc, 1. In Position 1 of the regulating shaft end of the middle flat disc: The speed regulating power is transmitted from the regulating shaft end of the middle flat disc to one speed regulating pinion of the middle flat disc and then transmitted to each of the rest of speed regulating pinions of the middle flat discs through the speed regulating gearwheel of the middle flat disc; 2. In Position 2 of the regulating shaft end of the middle flat disc: The speed regulating power is transmitted to the speed regulating gearwheel of the middle flat disc from the regulating shaft end of the middle flat disc and then transmitted to each of the rest of speed regulating pinions of the middle flat discs by the speed regulating gearwheel of the middle flat disc, and each speed regulating pinion of the middle flat disc drives each middle flat disc to move back and forth along the axis of the lead screw of the middle flat disc through the speed regulating ratio system of each middle flat disc to realize the regulation of speed ratio by the middle flat disc. 
         [0015]    Parallel and serial structure: The number of middle flat discs connected with the same driven flat disc (including the fixed driven flat disc, the sliding driven flat disc and the middle driven flat disc) is considered as the number of parallel connections, the invention can have more than two (including two) middle flat discs in parallel, the number of the speed regulating ratio systems of each middle flat disc is also the same as the number of middle flat discs in parallel; the structure between every two neighboring driven flat discs (including the fixed driven flat disc, the sliding driven flat disc and the middle driven flat disc) is called as a transmission, more than two (including two) transmissions can be connected in series, and the number of transmissions in series is the number of serial connections for the continuously variable transmission. Manner of serial connection: Multiple transmissions in series share the same output shaft, multiple transmissions in series shaar the same input shaft and the number of speed regulating ratio systems for each middle flat disc is also the same as the number of middle flat discs in parallel. 
         [0016]    Work principles of the continuously variable transmission: 
         [0000]    1. Work principle of power transmission: Power enters the continuously variable transmission from the input shaft, and the power is transmitted to the input shaft gear through the input shaft. Power transmission route according to the schemes for the structural system of input shaft gear, intermediate gear of the driving flat disc and driving flat disc gear: 1. The input shaft gear transmits the power to one driving flat disc gear, and the driving flat disc gear then transmits the power to other driving flat disc gears through the intermediate gear of the driving flat disc; 2. Each pair of neighboring driving flat disc gears are connected by one intermediate gear of the driving flat disc, the input shaft gear transmits the power to each driving flat disc gear through the intermediate gear of the driving flat disc. 3. The input shaft gear transmits the power to two driving flat disc gears simultaneously, and then one of the driving flat disc gears transmits the power to the other driving flat disc gear through the intermediate gear of the driving flat disc. The driving flat disc gear then transmits the power to the driving flat discs, when the hydraulic cylinder is compressed, the driving flat discs transmit the power to middle flat disc by friction, the middle flat disc also transmits the power to the fixed driven flat disc and the sliding driven flat disc through friction, the power is transmitted to the output shaft through the driven flat discs, and the power is transmitted out of the transmission by the output shaft.
 
2. Work principle of the hydraulic cylinder: After the hydraulic oil is pressurized, on the one hand, the oil pressure acts on the sliding driven flat disc; on the other hand, the oil pressure acts on the hydraulic plate, the hydraulic plate pulls the hinge of the hydraulic lever through the hinging base of the hydraulic lever, then the hinge of the hydraulic lever pulls the hydraulic lever, and the hydraulic lever compresses the sliding driven flat disc through the hydraulic lever block by taking the hydraulic lever bracket as the fulcrum.
 
3. Work principle for speed regulating ratio of middle flat disc: It is specified that the speed ratio is obtained by dividing the absolute value of the input shaft speed by the absolute value of the output shaft speed. The speed regulating power enters the continuously variable transmission from the regulating shaft end of the middle flat disc, 1. In the structure that the regulating shaft end of the middle flat disc is fixed on the regulating shaft of the middle flat disc, the speed regulating power is transmitted from the regulating shaft end of the middle flat disc to one speed regulating pinion of the middle flat disc, then speed regulating pinion of the middle flat disc transmits the speed regulating power to the speed regulating gearwheel of the middle flat disc, the speed regulating gearwheel of the middle flat disc then transmits it to each of the rest of speed regulating pinions of the middle flat disc, and each speed regulating pinion of the middle flat disc drives each middle flat disc to move back and forth along the axis of the lead screw of the middle flat disc through the speed regulating ratio system of each middle flat disc to realize the regulation of the speed ratio of the middle flat disc; 2. In the structure that the regulating shaft end of the middle flat disc is separately fixed and connected with the regulating shaft end gear of the middle flat disc, the regulating shaft end gear of the middle flat disc is matched with the speed regulating gearwheel of the middle flat disc, the speed regulating power is transmitted from the regulating shaft end of the middle flat disc to the speed regulating gearwheel of the middle flat disc through the regulating shaft end gear of the middle flat disc, the speed regulating gearwheel of the middle flat disc then transmits it to each of the rest of speed regulating pinions of the middle flat disc, and each speed regulating pinion of the middle flat disc drives each middle flat disc to move back and forth along the axis of the lead screw of the middle flat disc through the speed regulating ratio system of each middle flat disc to realize the regulation of speed ratio of the middle flat disc.
 
         [0017]    Since the structure of the invention is adopted, the continuously variable transmission has the following beneficial effects: 
         [0018]    1. Big power and torque of power transmission, and small power loss. 
         [0019]    2. Function of forward and reverse conversion. 
         [0020]    3. The lead screw of the middle flat disc is arranged on the side of the middle flat disc, the size of the middle flat disc can be smaller, and the strength of the lead screw of the middle flat disc can be higher. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    The figures are explained below: 
           [0022]      FIG. 1  is the A-A section view of  FIG. 5  and the structural drawing of the continuously variable transmission, and the middle flat disc is in the forward position of the power output shaft; 
           [0023]      FIG. 2  is the B-B section view of  FIG. 5  and the structural drawing of the continuously variable transmission, and the position of the input shaft can be seen in the figure; 
           [0024]      FIG. 3  is the section view of the serial structure of two continuously variable 
           [0025]    Specification transmissions; 
           [0026]      FIG. 4  is the matching drawing of the middle flat disc with the lead screw of the middle flat disc, and the middle flat disc is in the farthest distance from the output shaft; 
           [0027]      FIG. 5  is the matching drawing of the middle flat disc with the lead screw of the middle flat disc matching drawing, and the middle flat disc is in the nearest distance from the output shaft; 
           [0028]      FIG. 6  is the sketch map of Scheme 1 for the structural system of input shaft gear, intermediate gear of the driving flat disc and driving flat disc gear in the structure of three middle flat discs in parallel; 
           [0029]      FIG. 7  is the sketch map of Scheme 2 for the structural system of input shaft gear, intermediate gear of the driving flat disc and driving flat disc gear in the structure of three middle flat discs in parallel; 
           [0030]      FIG. 8  is the sketch map of Scheme 3 for the structural system of input shaft gear, intermediate gear of the driving flat disc and driving flat disc gear in the structure of three middle flat discs in parallel; 
           [0031]      FIG. 9  is the second structural sketch map of Scheme 1 for the structural system of input shaft gear, intermediate gear of the driving flat disc and driving flat disc gear in the structure of three middle flat discs in parallel; 
           [0032]      FIG. 10  is the layout drawing that a middle flat disc bracket and a lead screw of the middle flat disc is arranged on the each middle flat disc, and the axis of the middle flat disc bracket is vertical to the axis of the output shaft; 
           [0033]      FIG. 11  is the layout drawing that a middle flat disc bracket and lead screw of the middle flat disc are arranged on each middle flat disc, the axis of the middle flat disc bracket is in a certain angle with the axis of the output shaft; 
           [0034]      FIG. 12  is the layout drawing that two middle flat disc brackets and two lead screw of the middle flat discs are arranged on the each middle flat disc, and the axes of the middle flat disc brackets are vertical to the axis of the output shaft; 
           [0035]      FIG. 13  is the layout drawing that two middle flat disc brackets and two lead screw of the middle flat discs are arranged on the each middle flat disc, and the axes of the middle flat disc brackets are in a certain angle with the axis of the output shaft; 
           [0036]      FIG. 14  is the D-D section view of  FIG. 16 , as well as the structural drawing that the lead screw of the middle flat disc is a ball lead screw and the lead screw nut on the middle flat disc bracket is a ball; 
           [0037]      FIG. 15  is the E-E section view of  FIG. 14 , as well as the structural drawing that the lead screw of the middle flat disc is a ball lead screw, the lead screw nut on the middle flat disc bracket is a ball nut, and the external loop orbit is indicated; 
           [0038]      FIG. 16  is the structural drawing that the middle flat disc has no center hole, the middle flat disc bearing is installed on the center shaft of the middle flat disc, the center shaft of the middle flat disc is fixed and connected or integrated with the middle flat disc; 
           [0039]      FIG. 17  is the structural drawing that the double-layer bearing of the middle flat disc is in the center hole of the middle flat disc; 
           [0040]      FIG. 18  is the structural drawing that the single-layer bearing of the middle flat disc is in the center hole of the middle flat disc; 
           [0041]      FIG. 19  is the structural drawing that the double-layer bearing of the middle flat disc is in the center hole of the middle flat disc, and the middle flat disc is thickened; 
           [0042]      FIG. 20  is the top view of  FIG. 16 ; 
           [0043]      FIG. 21  is the top view of  FIG. 17 ; 
           [0044]      FIG. 22  is the top view of  FIG. 18 ; 
           [0045]      FIG. 23  is the top view of  FIG. 19 ; 
           [0046]      FIG. 24  shows the phase of forward and reverse conversion that the middle flat disc is closest to the bracket beam of the driving flat disc; 
           [0047]      FIG. 25  shows the phase of forward and reverse conversion from the middle flat disc to the top of the middle beam of the driving flat disc; 
           [0048]      FIG. 26  shows the phase of forward and reverse conversion that middle flat disc passes over the top of the middle beam of the driving flat disc; 
           [0049]      FIG. 27  shows the phase of forward and reverse conversion that middle flat disc passes over the middle beam of the driving flat disc; 
           [0050]      FIG. 28  shows that the middle flat disc passes over the middle beam of the driving flat disc and starts to reverse; 
           [0051]      FIG. 29  is the structural drawing for Position 2 of the regulating shaft end of the middle flat disc, showing the matching relations of the speed regulating pinion of the middle flat disc, the regulating shaft end of the middle flat disc and the regulating shaft end gear of the middle flat disc with the speed regulating gearwheel of the middle flat disc; 
           [0052]      FIG. 30  is the left view of  FIG. 31 ; 
           [0053]      FIG. 31  is the structural drawing for the half bracket I of the driving flat disc; 
           [0054]      FIG. 32  is the right view of  FIG. 31 ; 
           [0055]      FIG. 33  is the left view of  FIG. 34 ; 
           [0056]      FIG. 34  is the structural drawing for the half bracket II of the driving flat disc; 
           [0057]      FIG. 35  is the left view of  FIG. 34 ; 
           [0058]      FIG. 36  is the component matching relation drawing of the half bracket I of the driving flat disc and the half bracket II of the driving flat disc with the driving flat disc; 
           [0059]      FIG. 37  is the matching relation drawing of the half bracket II of the driving flat disc with the driving flat disc gear, the input shaft gear and the intermediate gear of the driving flat disc; 
           [0060]      FIG. 38  is the matching relation drawing of the intermediate gear of the driving flat disc with the half bracket I of the driving flat disc and the half bracket II of the driving flat disc; 
           [0061]      FIG. 39  is the structural drawing of the transmission with middle flat discs in parallel, and the middle flat disc is in the nearest position to the output shaft; 
           [0062]      FIG. 40  the structural drawing of the transmission with middle flat discs in parallel, in the structural drawing, Scheme 1 for the structural system of input shaft gear, intermediate gear of the driving flat disc and driving flat disc gear: the input shaft gear is matched with two driving flat disc gears, and the two driving flat disc gears are matched with another two driving flat disc gears through the intermediate gear of the driving flat disc, respectively; 
           [0063]      FIG. 41  is the structural drawing of Position 2 of the regulating shaft end of the middle flat disc in the transmission with four middle flat discs in parallel, showing the matching relations of the speed regulating pinion of the middle flat disc, the regulating shaft end of the middle flat disc and the regulating shaft end gear of the middle flat disc with the speed regulating gearwheel of the middle flat disc; 
           [0064]      FIG. 42  is the structural drawing of the transmission with four middle flat discs in parallel. In the structural drawing, Scheme 2 for the structural system of input shaft gear, intermediate gear of the driving flat disc and driving flat disc gear; The input shaft gear is matched with one driving flat disc gear, and two neighboring driving flat disc gears are matched with the intermediate gear of the driving flat disc arranged between them; 
           [0065]      FIG. 43  is the structural drawing of the transmission with four middle flat discs in parallel, and the middle flat disc is the farthest position from the output shaft; 
           [0066]      FIG. 44  is the C-C section view of  FIG. 46 , and the middle flat disc is in the forward position; 
           [0067]      FIG. 45  is the structural drawing of the transmission with five middle flat discs in 
           [0068]    Specification parallel, and the middle flat disc is in the forward position; 
           [0069]      FIG. 46  is the structural drawing of the transmission with five middle flat discs in parallel, and the middle flat disc is the farthest position from the output shaft; 
           [0070]      FIG. 47  shows Scheme 2 for the structural system of input shaft gear, intermediate gear of the driving flat disc and driving flat disc gear in the structure of the continuously variable transmission with five middle flat discs in parallel: the input shaft gear is matched with one driving flat disc gear; and two neighboring driving flat disc gears are matched with the intermediate gear of the driving flat disc arranged between them; 
           [0071]      FIG. 48  is the structural drawing of the transmission with five middle flat discs in parallel, and the middle flat disc is in the nearest position to the output shaft; 
           [0072]      FIG. 49  shows Scheme 1 for the structural system of input shaft gear, intermediate gear of the driving flat disc and driving flat disc gear in the structure of the continuously variable transmission with five middle flat discs in parallel: the input shaft gear is matched with two driving flat disc gears, the two driving flat disc gears are matched with another two driving flat disc gears through the intermediate gear of the driving flat disc, respectively, and the fifth driving flat disc gear is matched with one neighboring driving flat disc gear through the intermediate gear of the driving flat disc; 
       
    
    
       [0073]    In the figures:  1 —Speed regulating pinion of the middle flat disc;  2 —Bracket beam of the driving flat disc;  3 —Lead screw gear of the middle flat disc;  4 —Lead screw of the middle flat disc;  5 —Regulating shaft of the middle flat disc gear;  6 —Regulating shaft of the middle flat disc;  7 —Driving flat disc key;  8 —Driving flat disc nut;  9 —Mandrel bolt of the driving flat disc;  10 —Half bracket I of the driving flat disc;  11 —Fixed driven flat disc;  12 —Middle flat disc bracket;  13 —Fixing snap ring of the fixed driven flat disc;  14 —Driven flat disc groove;  15 —Hydraulic cylinder block;  16 —Middle flat disc;  17 —Hinge of the hydraulic lever;  18 —Hydraulic lever;  19 —Hinging base of the hydraulic lever;  20 —Hydraulic plate;  21 —Hydraulic lever bracket;  22 —Hydraulic plate spring;  23 —Positioning pin of the hydraulic lever bracket;  24 —Oil way communicator;  25 —Oil inlet of the hydraulic cylinder;  26 —Driving flat disc mandrel I;  27 —Middle driven flat disc;  28 —Hydraulic lever block;  29 —Driving flat disc;  30 —Driving flat disc gear;  31 —Hydraulic oil way;  32 —bracket bolt of the driving flat disc;  33 —Middle fiat disc bearing;  34 —Driving flat disc mandrel II;  35 —Half bracket II of the driving flat disc;  36 —Output shaft;  37 —Speed regulating gearwheel of the middle flat disc;  38 —Sliding driven flat disc;  39 —lead screw for the bearing seat of the middle flat disc;  40 —Intermediate gear of the driving flat disc;  41 —Input shaft gear;  42 —Input shaft;  43 —Housing;  44 —bracket key groove of the driving flat disc;  45 —Intermediate gear of the driving flat disc shaft;  46 —Regulating shaft end of the middle flat disc;  47 —Regulating shaft end gear of the middle flat disc;  48 —Ball of the ball lead screw;  49 —External loop channel of ball nut;  50 —Key groove of the housing;  51 —Bearing seat of the input shaft;  52 —Lead screw nut of the middle flat disc. 
       DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0074]    It can be seen in  FIG. 1 ,  FIG. 2 ,  FIG. 3 ,  FIG. 4 ,  FIG. 9 ,  FIG. 24 ,  FIG. 25 ,  FIG. 26 ,  FIG. 27 ,  FIG. 28 ,  FIG. 29 ,  FIG. 30 ,  FIG. 31 ,  FIG. 32 ,  FIG. 33 ,  FIG. 34 ,  FIG. 35 ,  FIG. 36 ,  FIG. 37  and  FIG. 38 , driving flat disc system: A pair of driving flat discs  29  are matched with the driving flat disc gear  30  through the driving flat disc key  7  and tightened by the driving flat disc nut  8 , the bracket beams  2  of the driving flat disc are arranged on both the half bracket I  10  of the driving flat disc and the half bracket II  35  of the driving flat disc, the driving flat disc mandrel I  26  is arranged in the middle of the bracket beam  2  of the driving flat disc on the half bracket I  10  of the driving flat disc, the driving flat disc mandrel II  34  is arranged in the middle of the bracket beam  2  of the driving flat disc on the half bracket II  35  of the driving flat disc, the half bracket I  10  of the driving flat disc and the half bracket II  35  of the driving flat disc are tightened and fixed with the bracket bolt of the driving flat disc  32  through the mandrel bolt  9  of the driving flat disc, and the driving flat disc is in running fit with the driving flat disc mandrel I  10  and the driving flat disc mandrel II  35  through bearings. The lowest point of the bracket beam  2  of the driving flat disc is higher than the plane of the driving flat disc  29 . 
         [0075]    Power output system: The driven flat disc grooves  14  are arranged on the driven flat discs (including the fixed driven flat disc  11 , the middle driven flat disc  27  and the sliding driven flat disc  38 ), the output shaft  36  passes through the center hole of the fixed driven flat disc  11 , the fixed driven flat disc  11  is fixed and connected with the output shaft  36 , the sliding driven flat disc  38  and the output shaft  36  can relatively slide but can&#39;t relatively rotate, the output shaft  36  passes through the center hole of the sliding driven flat disc  11 , the sliding driven flat disc  11  is fixed and connected with the hydraulic cylinder block  15 , and the power is transmitted out of the transmission by the output shaft  36 . 
         [0076]    Forward and reverse conversions: 1. The forward and reverse conversions of the continuously variable transmission shall be completed by the middle flat disc  16  spanning from one side of the bracket beam  2  of the driving flat disc to the other side of the bracket beam  2  of the driving flat disc, namely, along with the rotation of the lead screw  4  of the middle flat disc, the middle flat disc  16  is moved to the position close to the bracket beam  2  of the driving flat disc (see  FIG. 24 ); 2. One end of the middle flat disc  16  continues to move along the bevel of the bracket beam  2  of the driving flat disc, and it continues to move after reaching the top of the bracket beam  2  of the driving flat disc (see  FIG. 25  and  FIG. 26 ); 3. The other end of the middle flat disc  16  continues to move along the bevel of the driven flat disc grooves  14  of the driven flat discs (including the fixed driven flat disc  11 , and the sliding driven flat disc  38  and the middle driven flat disc  27 ), so that the middle flat disc  16  can reach the other side of the bracket beam  2  of the driving flat disc (see  FIG. 27  and  FIG. 28 ); owing to the existence of the driven flat disc grooves  14 , the other end of the middle flat disc can move in the driven flat disc grooves  14 . 
         [0077]    Structural scheme of the driven flat disc grooves  14 : 1. When the driven flat disc grooves  14  are deep enough, as the middle flat disc  16  gets across the driven flat disc grooves  14 , the compaction system is decompressed, and the middle flat disc  16  can also span over the bracket beam  2  of the driving flat disc without moving the sliding driven flat disc; 2. When the driven flat disc grooves  14  are not deep enough, as the middle flat disc gets across the driven flat disc grooves  14 , the compaction system is decompressed, and the middle flat disc can span over the bracket beam  2  of the driving flat disc only when the sliding driven flat disc  38  is moved towards the compaction system for a certain distance, but the moving distance of the sliding driven flat disc  38  shall be less than that when there is no sliding driven flat disc groove  14  on the sliding driven flat disc  38 , the continuously variable transmission can be made into smaller size, and the cross section of the bracket beam  2  of the driving flat disc can be made into bigger area. This kind of transmission can use the forward function but not use the reverse function. 
         [0078]    Compaction system: The hydraulic compaction system comprises a hydraulic lever bracket  21  which is fixed and connected with the output shaft  36 , and when the hydraulic cylinder is compressed, one end of the hydraulic lever  18  pushes against the sliding driven flat disc  38 : one end of the hydraulic lever  18  is contacted with the sliding driven flat disc  38  through the hydraulic lever block  28 ; the hole in the middle of the hydraulic lever  18  is hinged with the hydraulic lever bracket  21 , and the hydraulic plate  20  pulls the other end of the hydraulic lever  18 : the hole at the other end of the hydraulic lever  18  can be hinged with one end of the hinge  17  of the hydraulic lever, and the other end of the hinge  17  of the hydraulic lever can be hinged with the hinging base  19  of the hydraulic lever, and the hinging base  19  of the hydraulic lever is fixed on the hydraulic plate  20 ; the output shaft  36  passes through the center hole of the hydraulic plate  20 , and the hydraulic plate  20  can slide on the output shaft  36  relative to it. 
         [0079]    Speed regulating ratio system of the middle flat disc: It is specified that the speed ratio is obtained by dividing the absolute value of input shaft  42  speed by the absolute value of output shaft  36  speed, the speed regulating ratio system of each middle flat disc  16 : the lead screw  39  for the bearing seat of the middle flat disc is fixed and connected with the housing  43 , one end of the lead screw  4  of the middle flat disc is installed on the lead screw  39  for the bearing seat of the middle flat disc through the bearing, the other end of the lead screw  4  of the middle flat disc is installed on the housing  43  through the bearing, the threaded part of the lead screw  4  of the middle flat disc is matched with the lead screw nut  52  of the middle flat disc on the middle flat disc bracket  12 , the lead screw nut  52  of the middle flat disc is fixed and connected or integrated with the middle flat disc bracket  12 , and along with the rotation of the lead screw  4  of the middle flat disc, the lead screw nut  52  of the middle flat disc drives the middle flat disc bracket  12  and the middle flat disc  16  to move back and forth along with the axis of the lead screw  4  of the middle flat disc to realize the process of speed regulating ratio for the middle flat disc  16 . The lead screw gear  3  of the middle flat disc is fixed on the lead screw  4  of the middle flat disc, the lead screw gear  3  of the middle flat disc can be a worm gear, and the lead screw gear  3  of the middle flat disc, is matched with the regulating shaft  5  of the middle flat disc gear on the regulating shaft  6  of the middle flat disc; the regulating shaft  5  of the middle flat disc gear can be a worm, the regulating shaft  5  of the middle flat disc gear is fixed and connected with the regulating shaft  6  of the middle flat disc, the regulating shaft  6  of the middle flat disc is arranged vertical to the axis of the lead screw  4  of the middle flat disc, the regulating shaft  6  of the middle flat disc is arranged in parallel with the output shaft  36 , and the speed regulating pinion  1  of the middle flat disc on the regulating shaft  6  of the middle flat disc is fixed and connected with the regulating shaft  6  of the middle flat disc. 
         [0080]    Position 1 of the regulating shaft end  46  of the middle flat disc: The regulating shaft end  46  of the middle flat disc, is arranged on one speed, regulating pinion  1  of the middle flat disc (see  FIG. 2 ); 
         [0081]    Position 2 of the regulating shaft end  46  of the middle flat disc: The regulating shaft end  46  of the middle flat disc is separately matched with the gear  47  at the regulating shaft end of the middle flat disc, and the regulating shaft end  46  of the middle fiat disc is matched with the speed regulating gearwheel  37  of the middle flat disc ( FIG. 29 ). 
         [0082]    The speed regulating pinion  1  of the middle flat disc of the speed regulating ratio system of each middle flat disc  16  is matched with the same speed regulating gearwheel  37  of the middle flat disc, 1. In Position 1 of the regulating shaft end  46  of the middle flat disc: The speed regulating power is transmitted from the regulating shaft end  46  of the middle flat disc to one speed regulating pinion  1  of the middle flat disc and then transmitted to each of the rest of speed regulating pinions  1  of the middle flat discs through the speed regulating gearwheel  37  of the middle flat disc; 2. In Position 2 of the regulating shaft end  46  of the middle flat disc: The speed regulating power is transmitted to the speed regulating gearwheel  37  of the middle flat disc from the regulating shaft end  46  of the middle flat disc, and then transmitted to each of the rest of speed regulating pinions  1  of the middle flat discs by the speed regulating gearwheel  37  of the middle flat disc, and each speed regulating pinion  1  of the middle flat disc drives each middle flat disc  16  to move back and forth along the axis of the lead screw  4  of the middle flat disc through the speed regulating ratio system of each middle flat disc  16  to realize the regulation of speed ratio by the middle flat disc  16 . 
         [0083]    The bracket keys of the driving flat disc are added in the housing key groove  50  (see  FIG. 4  and  FIG. 5 ) and the bracket key groove  44  of the driving flat disc (see  FIG. 30  and  FIG. 32 ) on the housing  43 , so that the driving flat disc bracket (including the half bracket I  10  of the driving flat disc and the half bracket II  35  of the driving flat disc) can only slide relative to the axis of the housing  43  but can&#39;t rotate. 
         [0084]    It can be seen in  FIG. 10 ,  FIG. 11 ,  FIG. 12 ,  FIG. 13 ,  FIG. 14 ,  FIG. 15 ,  FIG. 16 ,  FIG. 17 ,  FIG. 18 ,  FIG. 19 ,  FIG. 20 ,  FIG. 21 ,  FIG. 22  and  FIG. 23 , middle flat disc  16  system: the lead screw nut  52  of the middle flat disc at one end of the middle flat disc bracket  12  is matched with the lead screw  4  of the middle flat disc  4 , the other end is matched with the middle flat disc  16  through the middle flat disc bearing, the lead screw  4  of the middle flat disc is arranged on the side of the middle flat disc  16 , the lead screw nut  52  of the middle flat disc is integrated or fixed and connected with the middle flat disc bracket  12 , and the middle flat disc  16  works between the driving flat disc  29  and the driven flat discs (including the fixed driven flat disc  11 , the sliding driven flat disc  38  and the middle driven flat disc  27 ). The lead screw of the middle flat disc can be sliding lead screw, rolling lead screw (including ball lead screw and roller lead screw) and hydrostatic lead screw, and the matched lead screw nut  52  of the middle flat disc can be sliding screw nut, rolling screw nut (including ball nut and roller nut) and hydrostatic nut. Middle flat disc system: The lead screw nut  52  of the middle flat disc on one part of the middle flat disc bracket  12  is matched with the lead screw  4  of the middle flat disc, the other part of the middle flat disc bracket  12  is matched with the middle flat disc  16  through the middle flat disc bearing  33 , the lead screw  4  of the middle flat disc is arranged on the side of the middle flat disc  16 , the lead screw nut  52  of the middle flat disc is integrated or fixed and connected with the middle flat disc bracket  12 , and the middle flat disc  16  works between the driving flat discs and the driven flat discs (including the fixed driven flat disc  11 , the sliding driven flat disc  38  and the middle driven flat disc  27 ). The lead screw  4  of the middle flat disc can be sliding lead screw, rolling lead screw (including ball lead screw and roller lead screw) and hydrostatic lead screw; the matched lead screw nut of the middle flat disc can be sliding nut, rolling nut (including ball nut and roller nut) and hydrostatic nut. 
         [0000]    Several schemes of the middle flat disc: 1. The middle flat disc bearing  55  is a double-layer bearing arranged in the center role of the middle flat disc  10  (see  FIG. 17  and  FIG. 21 ). 2. The middle flat disc bearing  55  is a single-layer bearing arranged in the center hole of the middle flat disc  10  (see  FIG. 18  and  FIG. 22 ). 3. The middle flat disc bearing  55  is a double-layer bearing arranged in the center role of the middle flat disc  10 , and the middle flat disc  10  is thickened (see  FIG. 19  and  FIG. 23 ). 4. The middle flat disc  10  has no center hole, the middle flat disc bearing  55  is installed on the center shaft of the middle flat disc  10 , and the center shaft of the middle flat disc  10  is fixed and connected or integrated with the middle flat disc  10  (see  FIG. 16  and  FIG. 20 ); Type 1 of the middle flat disc bracket  12 , 1. Each middle flat disc  10  has one middle flat disc bracket  12  and one lead screw  6  of the middle flat disc  6 , and the axis of the middle flat disc bracket  12  is vertical to the axis of the output shaft  37  (see  FIG. 10 ); 2. Each middle flat disc  10  has one middle flat disc bracket  12  and one lead screw  6  of the middle flat disc, the axis of the middle flat disc bracket  12  is in a certain angle with the axis of the output shaft  37  (see  FIG. 11 ); 3. Each middle flat disc  10  has two middle flat disc brackets  12  and two lead screws  6  of the middle flat disc, the axes of the middle flat disc brackets  12  are vertical to the axes of the output shaft  37  (see  FIG. 12 ); 4. Each middle flat disc  10  has two middle flat disc brackets  12  and two lead screws  6  of the middle flat disc, and the axes of the middle flat disc brackets  12  are in a certain angle with the axes of the output shafts  37  (see  FIG. 13 ). 
         [0085]    It can be seen in  FIG. 6 ,  FIG. 7 ,  FIG. 8  and  FIG. 9 , power input system: In the structure of three middle flat discs  16  in parallel, schemes for the structural system of input shaft gear  41 , intermediate gear  40  of the driving flat disc and driving flat disc gear  30 : 1. The input shaft gear  41  is matched with one driving flat disc gear  30 , and each pair of neighboring driving flat disc gears  30  are matched with the same intermediate gear  40  of the driving flat disc (see  FIG. 6  and  FIG. 9 ); 2. Each pair of neighboring driving flat disc gear  30  are matched with the same intermediate gear  40  of the driving flat disc, and the input shaft gear  41  transmits power to each driving flat disc gear  30  through the intermediate gear  40  of the driving flat disc (see  FIG. 7 ); 3. The input shaft gear  41  transmits the power to two driving flat disc gears  30  simultaneously, and one of the driving flat disc gears  30  then transmits the power to the other driving flat disc gear  30  through the intermediate gear  40  of the driving flat disc (see  FIG. 8 ). This kind of continuously variable transmission has intermediate gear  40  of the driving flat discs which can be matched with two driving flat disc gears  30 , respectively, and the intermediate gear  40  of the driving flat disc can be matched with the input shaft gear  41  at the same time of matching with one driving flat disc gear  30 . 
         [0086]    The position of middle flat disc  16  in  FIG. 6  is the minimum reverse speed ratio; the position of middle flat disc  16  in  FIG. 7  is the maximum reverse speed ratio; the position of middle flat disc  16  in  FIG. 8  is the maximum forward speed ratio; the position of middle flat disc  16  in  FIG. 9  is the minimum forward speed ratio. 
         [0087]    It can be seen in  FIG. 39 ,  FIG. 40 ,  FIG. 41 ,  FIG. 42  and  FIG. 43  that, in the continuously variable transmission with four middle flat discs  16  in parallel, except that the number of middle flat discs  16  is increased by ⅓ than the number of middle flat discs  16  with three middle flat discs  16  in parallel, and the numbers of the rest of components matched with the middle flat disc  16  are also increased by ⅓ accordingly. 
         [0088]    It can be seen in  FIG. 44 ,  FIG. 45 ,  FIG. 46 ,  FIG. 47 ,  FIG. 48  and  FIG. 49 , in the continuously variable transmission with five middle flat discs  16  in parallel, except that the number of middle flat discs  16  is increased by ⅔ than the number of middle flat discs  16  with three middle flat discs  16  in parallel, and the numbers of the rest of components matched with the middle flat disc  16  are also increased by ⅔ accordingly. 
         [0089]    In the figures, parallel and serial structure: the number of middle flat discs  16  connected with the same driven flat disc (including the fixed driven flat disc  11 , the middle driven flat disc  27  and the sliding driven flat disc  28 ) is considered as the number of parallel connections, the invention can have more than two (including two) middle flat discs  16  in parallel, the number of driving flat discs  29  is the same as the number of middle flat discs  16  in parallel, and the number of the speed regulating ratio systems of each middle flat disc  16  is also the same as the number of middle flat discs  16  in parallel; the structure between every two neighboring driven flat discs (including the fixed driven flat disc  11 , the sliding driven flat disc  38  and the middle driven flat disc  27 ) is called as a transmission, more than two (including two) transmissions can be connected in series, and the number of transmissions in series is the number of serial connections for the continuously variable transmission. Manner of serial connection: Multiple transmissions in series share the same output shaft  36 , multiple transmissions in series share the same input shaft  42 , and the number of speed regulating ratio systems for each middle flat disc  16  is also the same as the number of middle flat discs  16  in 
         [0090]    The work principles of the continuously variable transmission are explained by combining with the figures: 
         [0091]    1. Work principle of power transmission: Power enters the continuously variable transmission from the input shaft  42 , and the power is transmitted to the input shaft gear  41  through the input shaft  42 . Power transmission route according to the schemes for the structural system of input shaft gear 41, intermediate gear 40 of the driving flat disc and driving flat disc gear  30 : 1. The input shaft gear  41  transmits the power to one driving flat disc gear  30 , and the driving flat disc gear  30  then transmits the power to other driving flat disc gears  30  through the intermediate gear  40  of the driving flat disc; 2. Each pair of neighboring driving flat disc gears  30  are connected by one intermediate gear  40  of the driving flat disc, the input shaft gear  41  transmits the power to each driving flat disc gear  30  through the intermediate gear  40  of the driving flat disc. 3. The input shaft gear  41  transmits the power to two driving flat disc gears  30  simultaneously, and then one of the driving flat disc gears  30  transmits the power to the other driving flat disc gear  30  through the intermediate gear  40  of the driving flat disc. The driving flat disc gear  30  then transmits the power to the driving flat discs  29 , when the hydraulic cylinder is compressed, the driving flat discs  29  transmit the power to the middle flat disc  16  by friction, the middle flat disc  16  also transmits the power to the fixed driven flat disc  11  and the sliding driven flat disc  38  through friction, the power is transmitted to the output shaft  36  through the driven flat discs, and the power is transmitted out of the transmission by the output shaft  36 . 
         [0092]    2. Work principle of the hydraulic cylinder: After the hydraulic oil is pressurized, on the one hand, the oil pressure acts on the sliding driven flat disc  38 ; on the other hand, the oil pressure acts on the hydraulic plate  20 , the hydraulic plate  20  pulls the hinge  17  of the hydraulic lever through the hinging base  19  of the hydraulic lever, then the hinge  17  of the hydraulic lever pulls the hydraulic lever  18 , and the hydraulic lever  18  compresses the sliding driven flat disc  38  through the hydraulic lever block  28  by taking the hydraulic lever bracket  21  as the fulcrum. 
         [0093]    3. Work principle for speed regulating ratio of middle flat disc  16 : It is specified that the speed ratio is obtained by dividing the absolute value of the input shaft  42  speed by the absolute value of the output shaft  36  speed. The speed regulating power enters the continuously variable transmission from the regulating shaft end  46  of the middle flat disc, 1. In the structure that the regulating shaft end  46  of the middle flat disc is fixed on the regulating shaft  6  of the middle flat disc, the speed regulating power is transmitted from the regulating shaft end  461  of the middle flat disc to one speed regulating pinion of the middle flat disc, then the speed regulating pinion  1  of the middle flat disc transmits the speed regulating power to the speed regulating gearwheel  37  of the middle flat disc, the speed regulating gearwheel  37  of the middle flat disc then transmits it to each of the rest of speed regulating pinions  1  of the middle flat disc, and each speed regulating pinion  1  of the middle flat disc drives each middle flat disc  16  to move back and forth along the axis of the lead screw  4  of the middle flat disc through the speed regulating ratio system of each middle flat disc  16  to realize the regulation of the speed ratio of the middle flat disc  16 ; 2. In the structure that the regulating shaft end  46  of the middle flat disc is separately fixed and connected with the regulating shaft end  47  of the middle flat disc gear, the regulating shaft end  47  of the middle flat disc gear is matched with the speed regulating gearwheel  37  of the middle flat disc, the speed regulating power is transmitted from the regulating shaft end  46  of the middle flat disc to the speed regulating gearwheel  37  of the middle flat disc through the regulating shaft end  47  of the middle flat disc gear, the speed regulating gearwheel  37  of the middle flat disc then transmits it to each of the rest of speed regulating pinions  1  of the middle flat disc, each speed regulating pinion  1  of the middle flat disc drives each middle flat disc  16  to move back and forth along the axis of the lead screw  4  of the middle flat disc through the speed regulating ratio system of each middle flat disc  16  to realize the regulation of speed ratio of the middle flat disc  16 .