CN113915312A

CN113915312A - Constant force speed changing device

Info

Publication number: CN113915312A
Application number: CN202010659937.5A
Authority: CN
Inventors: 李晓锋; 曾小宝; 李小龙
Original assignee: Zhangjiajie Institute of Aeronautical Engineering
Current assignee: Zhangjiajie Institute of Aeronautical Engineering
Priority date: 2020-07-10
Filing date: 2020-07-10
Publication date: 2022-01-11

Abstract

An equi-force speed change device mainly comprises a first disc frame (1), a second disc frame (2), a third disc frame (3), a support (4), a belt pulley (5), a propping rod (7), a driving lever (8), a ball (9), a cushion block (10), a first spring (101) and a second spring (102), the equi-force speed change device is simple in manufacturing process and compact in structure, does not relate to gear manufacturing, only needs to adjust the distance of the driving lever (8) on the cushion block (10), the cushion block (10) is simple in structure, simple in manufacturing process and high in speed change ratio, the cushion block (10) and the ball (9) are replaced, the springs and the like are low in replacement cost, the machine adjustment after replacement is relatively easy, the existing gear speed changer is far less complicated, the product cost can be reduced, the taper positioning is adopted, the rotation distance of the second disc frame (2) at each time is subjected to taper calibration, thus, even if the pad (10) is worn, the rotational distance thereof is not affected accordingly.

Description

Constant force speed changing device

Technical Field

The application belongs to a speed changing device, and particularly relates to a speed reducing device.

Background

The machines that the speed output by the power machine becomes fast or slow are collectively called as speed change devices, and the speed change devices are divided into acceleration speed change devices and deceleration speed change devices according to the ratio of the output speed of the power machine to the speed after speed change, wherein the speed change devices comprise a plurality of belt pulley speed change devices, gear speed change devices, chain wheel speed change devices, stepless speed change devices, frequency converter speed change devices, hydraulic speed change devices, cycloid pin wheel speed change devices and the like. The ratio of the rotation speed before the gear change to the rotation speed after the gear change is referred to as a gear ratio, and in the case of gear change, the gear ratio of two meshed gears is the ratio of the number of gears, and since the meshed gears require the same pitch, that is, the outer diameter ratio of the meshed gears is also equal to the gear ratio, for example, if the required gear ratio is 1: 40, the number of teeth of the driven wheel is 800, the diameter of the driving wheel is 100mm, the diameter of the driven wheel is 4000mm, namely 4 meters, the equipment is too large and is not easy to process, the solution is multi-stage speed regulation, for example, three-stage speed regulation is adopted, the diameter of a single gear is reduced, however, multi-stage speed regulation needs a plurality of groups of meshing gears, the structure of a corresponding bearing and a gear box is also complicated, the product cost is increased as a result of the design, if the structure is compact and the speed change ratio is large, the existing machinery adopts more worm turbines for speed change, but the worm turbine speed change has the defects of low transmission efficiency and easy abrasion of tooth surfaces, so that the worm turbine gearbox has short service life, the worm turbine gearbox has higher cost, and the problems of belt pulley speed change, chain wheel speed change and stepless speed change are the same as the gear speed change, that is, the required speed ratio exceeds 1: 5 hours, the multi-stage speed regulation is often needed, the process complexity of the product is increased, the speed regulation of the frequency converter is achieved by changing the frequency of a power supply, the frequency range is usually between 1 and 400Hz, the power frequency in China is 50Hz, the speed regulation of the frequency converter is an electronic product which is very convenient for the speed regulation at present, but the frequency converter has the defects of high price, multiple faults and low service life, and is only used in the fields of numerical control machines, plastic machinery and the like which have complex speed regulation requirements and have higher limits on speed regulation technology, the fields of numerical control machines and plastic machinery, and the mechanical speed regulation cannot meet the complex speed regulation requirements.

Disclosure of Invention

The technical problems to be solved are as follows:

1. when the gear transmission box is used, processes such as gear shaping or gear hobbing, heat treatment and the like are needed in gear machining, so that the overall cost of the gear transmission box is relatively high.

2. With a gear box, accuracy after gear wear is problematic and it is difficult to use as a high accuracy conveyor.

The technical scheme is as follows:

an equal-force speed change device mainly comprises a first disc frame 1, a second disc frame 2, a third disc frame 3, a support 4, a belt pulley 5, a tightening rod 7, a shifting rod 8, a ball 9, a cushion block 10, a first spring 101 and a second spring 102, wherein the first disc frame 1 is installed on the support 4, the second disc frame 2 and the third disc frame 3 are installed on a main shaft 14, the first disc frame 1, the second disc frame 2 and the third disc frame 3 are concentric circles, the main shaft 14 is a part on the first disc frame 1, the main shaft 14 and the first disc frame 1 synchronously move, the belt pulley 5 is installed on the main shaft 14, when the equal-force speed change device works, power is transmitted to the belt pulley 5, the belt pulley 5 drives the main shaft 14 to rotate, the main shaft 14 drives the first disc frame 1 to rotate, the shifting rod 8 is driven to rotate, when the shifting rod 8 is driven to the position of the cushion block 10, the shifting rod 8 tightly abuts against the second disc frame 2 to drive the second disc frame 2 to rotate, and along with the continued rotation of the shifting rod 8, the deflector rod 8 leaves the cushion block 10, and the deflector rod 8 does not abut against the second disc 2 any more.

The disc frame I1 mainly comprises a disc I11, a deflector rod mounting hole 12, a spring II mounting position 13, a main shaft 14, a main shaft key groove 15 and a belt pulley locking screw hole 16, wherein the disc I11 and the main shaft 14 are concentric, the concentricity means that the central line of the disc I1 is coincident with the central line of the main shaft 14, the deflector rod mounting hole 12 is positioned on the disc I11, the deflector rod mounting hole 12 is a through hole and is used for mounting a deflector rod 8, the spring II mounting position 13 and the deflector rod mounting hole 12 are concentric, the aperture of the spring II mounting position 13 is larger than the outer diameter of a deflector rod body 81 and is also larger than the outer diameter of a spring II 102, the spring II mounting position 13 is used for mounting the spring II 102, the main shaft key groove 15 is positioned on the main shaft 14, the main shaft key groove 15 is matched with the key groove of the belt pulley 5 and is used for placing a pin key to prevent the belt pulley 5 from rotating on the main shaft 14, the belt pulley locking screw hole 16 is a threaded hole, and a screw rod and a gasket are utilized, the pulley 5 is prevented from falling off the main shaft 14.

The second disk frame 2 mainly comprises a second disk frame center hole 21, a second disk frame bearing position 22, a second end cover locking hole 23, a shift lever position 24 and a resisting rod resisting hole 25, the aperture of the second disk frame center hole 21 is larger than the outer diameter of the main shaft 14, the second disk frame center hole 21 penetrates through the main shaft 14, the second disk frame bearing position 22 is used for installing a bearing, the bearing is installed on the main shaft 14, therefore, the second disk frame 2 can freely rotate on the main shaft 14, the second end cover locking hole 23 is a threaded hole, the second disk frame end cover 62 is locked on the second disk frame 2 through a screw rod to prevent the bearing from loosening, the shift lever position 24 is a conical groove, the shift lever position 24 takes the circle center of the second disk frame 2 as a reference point and is distributed on the second disk frame 2 in a circumferential array, the distribution quantity of the shift lever positions 24 determines the gear ratio of the constant-force speed change device, the resisting rod resisting hole 25 is positioned on the back of the shift lever position 24, and corresponds to the shift lever position 24 in quantity, the abutting rod abutting hole 25 is a conical groove.

The disc rack III 3 mainly comprises a fastening rod mounting hole 31 and a spring mounting position 32, the disc frame three-locking hole 33 and the disc frame three-center hole 34 are formed, the abutting rod mounting holes 31 are distributed on the disc frame three 3 in a circumferential array by taking the circle center of the disc frame three 3 as a reference point, the number of the abutting rod mounting holes 31 corresponds to the shift lever positions 24, the abutting rod mounting holes 31 are through holes and are used for mounting the abutting rods 7, the spring first mounting positions 32 are concentric with the abutting rod mounting holes 31, the inner diameter of the spring first mounting positions 32 is larger than that of the abutting rod mounting holes 31, the spring first mounting positions 32 are used for mounting the spring first 101, the disc frame three-locking holes 33 are distributed in a circumferential array by taking the central line of the disc frame three 3 as a reference point, the screw penetrates through the disc frame three-locking holes 33 and is locked on the support through the disc frame three 3, the aperture of the disc frame three-center hole 34 is larger than the outer diameter of the main shaft 14, and the rotation of the main shaft 14 is facilitated.

The support 4 mainly comprises a support bearing hole 41, an end cover hole 42, a support fixing hole 43, a cushion block mounting hole 44, a support end cover locking hole 45 and a support center hole 46, wherein the support bearing hole 41 is used for mounting a bearing, the main shaft 14 is mounted on the bearing, the end cover hole 42 is a concave hole and is used for mounting a support end cover 61, the support fixing hole 43 is used for fixing the whole constant-force speed change device by using a screw rod, the cushion block mounting hole 44 is used for mounting the cushion block 10, the support end cover locking hole 45 is used for locking the support end cover 61 on the support 4 by using a screw rod to prevent the bearing from loosening, and the support center hole 46 is used for penetrating through the main shaft 14.

The resisting rod 7 mainly comprises a resisting rod annular position 71 and a resisting rod body 72, the outer diameter of the resisting rod annular position 71 is larger than the outer diameter of the resisting rod body 72, a first spring 101 is inserted into the resisting rod body 72, the first spring 101 can play a role due to the existence of the resisting rod annular position 71, the front end of the resisting rod 7 is conical, the conical degree of the resisting rod is the same as that of the resisting rod resisting hole 25, and the resisting rod 7 is withdrawn: when the disc frame 1 drives the disc frame 2 to rotate, the abutting rod abuts against the hole 25 to rotate, and the abutting rod abuts against the hole 25 to form a conical groove, so that when the torque generated when the disc frame 1 rotates is larger than the elastic force of the first spring 101, the first spring 101 is compressed, the abutting rod 7 retreats, and the abutting rod 7 abuts against the abutting process: when the front end of the abutting rod 7 is located in the abutting rod abutting hole 25, the first spring 101 acts to abut the abutting rod 7 against the abutting rod abutting hole 25, and the distance that the second disc rack 2 moves at each time is consistent due to the conical positioning effect.

The shift lever 8 mainly comprises a shift lever key groove 81, a spring third mounting position 82 and a ball mounting position 83, wherein a shift lever body 81 is inserted into the shift lever mounting hole 12, the shift lever body 81 is inserted into a spring second 102, the spring third mounting position 82 is used for mounting a spring third 103, and the ball mounting position 83 is used for mounting a ball 9

The process when the shift lever 8 is tightly pressed: when power is transmitted to the disc frame I1, the disc frame I1 rotates, the support is fixed, the disc frame I1 drives the shifting rod 8 to rotate together, when the shifting rod 8 runs to the position of the cushion block 10, the spring III 103 retreats, the ball 9 retreats along with the retreating, at the moment, if the moment when the disc frame I1 rotates is larger than the elastic force of the spring II 102, the spring II 102 retracts, the shifting rod 8 retreats and enters the cushion block 10, the rear end of the shifting rod body 81 is conical, the conical degree of the shifting rod body is the same as that of the shifting rod position 24, the rear end of the shifting rod body 81 tightly supports the shifting rod position 24, and as the shifting rod 8 continues to move forwards on the cushion block 10, the shifting rod 8 drives the disc frame II 2 to rotate;

the process when the shift lever 8 is released: when the shifting lever 8 leaves the cushion block 10, the third spring 103 advances, the ball 9 advances along with the advance, at the moment, the second spring 102 advances, the rear end of the shifting lever body 81 is driven to leave the shifting lever position 24, the first disc frame 1 continues to rotate, but the second disc frame 2 cannot rotate until the shifting lever 8 tightly abuts against the cushion block 10 again, and the process when the shifting lever 8 tightly abuts against is repeated.

The cushion block 10 mainly comprises an inclined plane 1001 and a cushion block hole 1002, the cushion block hole 1002 and the cushion block mounting hole 44 are in corresponding relation, the cushion block 10 is fixed on the support 4 through a screw, the inclined plane is a 20-45-degree inclined plane formed by two sides of the cushion block, and the thickness of the cushion block 10 is 2-5 mm larger than the depth of 24 degrees of the poking rod position.

Has the advantages that: the constant force speed change device has the advantages of simple manufacturing process, compact structure, no gear manufacturing is involved, only the distance of the deflector rod 8 on the cushion block 10 needs to be adjusted, the cushion block 10 has a simple structure, the manufacturing process is simple, the speed change ratio is high, the change part mainly comprises the cushion block 10 and the ball 9, the spring and the like, the change part cost is low, the machine adjustment after the change part is relatively easy, the machine adjustment is far less complicated than that of the existing gear speed changer, the product cost can be reduced, the taper positioning is adopted, the rotation distance of the disc frame 2 at each time is calibrated by the taper, and therefore, even if the cushion block 10 is abraded, the rotation distance cannot be correspondingly influenced.

Drawings

FIG. 1 is a schematic structural view of an isodynamic transmission;

FIG. 2 is a schematic diagram of an exploded structure of the constant force transmission;

FIG. 3 is a schematic structural view of a disc holder;

FIG. 4 is a schematic structural view of a second disc rack;

FIG. 5 is a schematic structural view of a second disk rack;

FIG. 6 is a schematic diagram of a third structure of a disc frame;

FIG. 7 is a schematic diagram of a stent structure;

FIG. 8 is a schematic view of a tightening rod;

FIG. 9 is a schematic view of the toggle lever;

FIG. 10 is a schematic view of a spacer;

in the figure, 1 is a first disk frame, 2 is a second disk frame, 3 is a third disk frame, 4 is a bracket, 5 is a belt pulley, 61 is a bracket end cover, 62 is a second disk frame end cover, 7 is a resisting rod, 8 is a deflector rod, 9 is a ball, 10 is a cushion block, 101 is a first spring, 102 is a second spring, 103 is a third spring, 11 is a first disk, 12 is a deflector rod mounting hole, 13 is a second spring mounting position, 14 is a main shaft, 15 is a main shaft key groove, 16 is a belt pulley locking screw hole, 21 is a second disk frame central hole, 22 is a second disk frame bearing position, 23 is a second end cover locking hole, 24 is a deflector rod position, 25 is a resisting rod resisting hole, 31 is a resisting rod mounting hole, 32 is a first spring mounting position, 33 is a third disk frame locking hole, 34 is a third disk frame central hole, 41 is a support bracket bearing hole, 42 is an end cover hole, 43 is a bracket fixing hole, 44 is a bracket end cover cushion block mounting hole, 45 is a bracket end cover locking hole, 46 is a support center hole, 71 is a tightening rod annular position, 72 is a tightening rod body, 81 is a poking rod body, 82 is a spring three mounting position, 83 is a ball mounting position, 1001 is an inclined plane, and 1002 is a cushion block hole.

Detailed Description

The applicant describes embodiments of the present application with reference to the attached drawings:

the attached drawings 1 and 2 are schematic structural diagrams of an equal-force speed change device, the equal-force speed change device mainly comprises a first disc frame 1, a second disc frame 2, a third disc frame 3, a support 4, a belt pulley 5, a resisting rod 7, a pulling rod 8, a ball 9, a cushion block 10, a first spring 101 and a second spring 102, the first disc frame 1 is installed on the support 4, the second disc frame 2 and the third disc frame 3 are installed on a main shaft 14, the first disc frame 1, the second disc frame 2 and the third disc frame 3 are concentric circles, the main shaft 14 is a part on the first disc frame 1, the main shaft 14 and the first disc frame 1 move synchronously, the belt pulley 5 is installed on the main shaft 14, during work, power is transmitted to the belt pulley 5, the belt pulley drives the main shaft 14 to rotate, the main shaft 14 drives the first disc frame 1 to rotate, the pulling rod 8 is driven to rotate, when the pulling rod 8 is driven to the position of the cushion block 10, the pulling rod 8 tightly abuts against the second disc frame 2 to drive the second disc frame 2 to rotate, when the shift lever 8 continues to rotate, the shift lever 8 leaves the cushion block 10, and the shift lever 8 does not abut against the second disk 2 any more.

FIG. 3 is a schematic structural view of a disc frame I1, the disc frame I1 mainly comprises a disc I11, a deflector rod mounting hole 12, a spring II mounting position 13, a main shaft 14, a main shaft key groove 15 and a belt pulley locking screw hole 16, the disc I11 and the main shaft 14 are in a concentric relation, the concentricity means that the central line of the disc and the central line of the main shaft are coincident, the deflector rod mounting hole 12 is positioned on the disc I11, the deflector rod mounting hole 12 is a through hole and is used for mounting a deflector rod 8, the spring II mounting position 13 and the deflector rod mounting hole 12 are concentric, the aperture of the spring II mounting position 13 is larger than the outer diameter of the deflector rod 8 and is also larger than the outer diameter of the spring II 102, the spring II mounting position 13 is used for mounting the spring II 102, the main shaft key groove 15 is positioned on the main shaft 14, the main shaft key groove 15 is matched with the key groove of the belt pulley 5 and is used for placing a pin key to prevent the belt pulley from rotating on the main shaft 14, and the belt pulley locking screw hole 16 is a threaded hole, the belt pulley is prevented from falling off from the main shaft by the screw and the gasket.

Fig. 4 and 5 are schematic structural views of a second disc frame 2, the second disc frame 2 mainly comprises a second disc frame center hole 21, a second disc frame bearing position 22, a second end cover locking hole 23, a shift lever position 24 and a resisting rod resisting hole 25, the aperture of the second disc frame center hole 21 is larger than the outer diameter of the main shaft 14, the second disc frame center hole 21 penetrates through the main shaft 14, the second disc frame bearing position 22 is used for mounting a bearing, the bearing is mounted on the main shaft 14, so that the second disc frame 2 can freely rotate on the main shaft 14, the second end cover locking hole 23 is a threaded hole, the second disc frame end cover 62 is locked on the second disc frame 2 by a screw rod, so that the bearing is prevented from loosening, the shift lever position 24 is a conical groove, the shift lever position 24 is distributed on the second disc frame 2 in a circumferential array by taking the center of the second disc frame 2 as a reference point, the distribution number of the shift lever positions 24 determines the gear ratio of the constant-force transmission device, for example, and 40 dial rod positions 24, the speed ratio is 1: 40, if the shift lever position 24 is 35, the transmission ratio is 1: 35, if the rotation speed of the motor is 1400RPM, the rotation speed is transmitted to the pulley 5 at a constant speed, the rotation speed after the speed change is 35 RPM and 40RPM, the abutting rod abutting holes 25 are located on the back of the shift lever position 24, the number of the abutting rod abutting holes corresponds to that of the shift lever position 24, and the abutting rod abutting holes 25 are conical grooves.

FIG. 6 is a schematic structural view of a disc frame III 3, the disc frame III 3 mainly comprises abutting rod mounting holes 31, spring first mounting positions 32, disc frame III locking holes 33 and disc frame III center holes 34, the abutting rod mounting holes 31 are distributed on the disc frame III 3 in a circumferential array by taking the circle center of the disc frame III 3 as a reference point, the number of the abutting rod mounting holes 31 corresponds to that of the shift lever positions 24, the abutting rod mounting holes 31 are through holes for mounting the abutting rods 7, the spring first mounting positions 32 are concentric with the abutting rod mounting holes 31, the inner diameter of the spring first mounting positions 32 is larger than that of the abutting rod mounting holes 31, the spring first mounting positions 32 are used for mounting the spring first 101, the disc frame III locking holes 33 are distributed in a circumferential array by taking the central line of the disc frame III 3 as a reference point, screws penetrate through the disc frame III locking holes 33 and are locked on a support through the disc frame III 3, the aperture of the disc frame III is larger than the outer diameter of the main shaft 14, facilitating rotation of the spindle 14.

Fig. 7 is a schematic structural diagram of a bracket 4, the bracket 4 mainly includes a bracket bearing hole 41, an end cover hole 42, a bracket fixing hole 43, a pad mounting hole 44, a bracket end cover locking hole 45, and a bracket center hole 46, the bracket bearing hole 41 is used for mounting a bearing, the main shaft 14 is mounted on the bearing, the end cover hole 42 is a recessed hole for mounting a bracket end cover 61, the bracket fixing hole 43 fixes the whole constant-force speed change device by using a screw, the pad mounting hole 44 is used for mounting a pad 10, the bracket end cover locking hole 45 is used for locking the bracket end cover 61 on the bracket by using a screw to prevent the bearing from loosening, and the bracket center hole 46 is used for penetrating the main shaft 14.

Fig. 8 is a schematic structural diagram of the tightening rod 7, the tightening rod 7 mainly comprises a tightening rod annular position 71 and a tightening rod body 72, the outer diameter of the tightening rod annular position 71 is larger than the outer diameter of the tightening rod body 72, the first spring 101 is inserted into the tightening rod body 72, the first spring 101 can only play a role due to the existence of the tightening rod annular position 71, the front end of the tightening rod 7 is conical, and has the same taper with the tightening rod tightening hole 25, so that when the first disc rack 1 drives the second disc rack 2 to rotate, the tightening rod tightening hole 25 rotates along with the rotation, because the tightening rod tightening hole 25 is a conical groove, when the torque of the first disc rack 1 during rotation is larger than the elastic force of the first spring 101, the tightening rod 7 retreats, the first spring 101 is compressed, which is a process when the tightening rod 7 retreats, and the tightening rod 7 resisting process is as follows: when supporting tight pole 7 front end and being located to support tight pole and supporting tight hole 25 within range, spring 101 effect will support tight pole 7 and support to supporting tight pole and support tight hole 25, because conical positioning action will guarantee that the distance that removes at every turn is unanimous, especially has certain error at the rotatory size of disc frame two 2, as long as the error is in certain within range, can both support the cooperation in tight pole 7 front end toper and support tight pole support tight hole 25 taper hole, guarantee the accuracy of rotation at every turn.

Fig. 9 is a schematic structural diagram of the shift lever 8, the shift lever 8 mainly comprises a shift lever body 81, a spring third mounting position 82 and a ball mounting position 83, the shift lever body 81 is inserted into the shift lever mounting hole 12, the shift lever body 81 is used for inserting the spring second 102, the spring third mounting position 82 is used for mounting the spring third 103, the ball mounting position 83 is used for mounting the ball 9,

the process when the shift lever 8 is tightly pressed: when power is transmitted to the disc frame I1, the disc frame I1 rotates, the support 4 is fixed, the disc frame I1 drives the shifting rod 8 to rotate together, when the shifting rod 8 runs to the position of the cushion block 10, the spring III 103 retreats, the ball 9 retreats along with the retreating, at the moment, if the moment when the disc frame I1 rotates is larger than the spring II 102, the spring II 102 retracts, the shifting rod 8 retreats and enters the cushion block 10, the rear end of the shifting rod body 81 is conical, the conical degree of the shifting rod body is the same as that of the shifting rod position 24, the rear end of the shifting rod body 81 tightly supports the shifting rod position 24, along with the fact that the shifting rod 8 continues to move forwards on the cushion block 10, the shifting rod 8 drives the disc frame II 2 to rotate.

Fig. 10 is a schematic diagram of a cushion block 10, the cushion block 10 mainly comprises an inclined plane 1001 and a cushion block hole 1002, the cushion block hole 1002 and the cushion block mounting hole 44 are in corresponding relation, the cushion block 10 is fixed on the support 4 by a screw rod, the inclined plane is a slope plane with 20-45 degrees formed by two sides of the cushion block, so that the balls 9 can stably enter the cushion block 10 and leave the cushion block 10, noise generated during product operation is reduced, the thickness of the cushion block is larger than the depth of a poking rod position 24, namely 2-5 mm, and the poking rod 8 can conveniently abut against the poking rod position 24 or withdraw from the poking rod position 24.

The constant force speed change device has the biggest advantages of simple manufacturing process and compact structure, does not relate to gear manufacturing, only needs to adjust the distance of a deflector rod 8 on a cushion block 10, has simple structure of the cushion block 10, simple manufacturing process and high speed change ratio, changes mainly a change cushion block 10, a ball 9, a spring and the like, has low part change cost, is relatively easy to adjust a machine after the part change, is far less complicated than the prior gear speed changer, can reduce the product cost, adopts taper positioning, and ensures that the rotating distance of a disc frame 2 at each time is calibrated by taper, so that the rotating distance of the disc frame cannot be influenced correspondingly even if the cushion block 10 is worn, and although the worm turbine gearbox has the advantages of compact structure and high speed change ratio, the constant force speed change device has the defects of easy wear, and inaccurate rotating distance of a turbine after being worn, and has no moment change, and thus is only suitable for areas where changes in torque are not critical.

Claims

1. An equi-force speed change device is characterized in that: the constant-force speed change device mainly comprises a first disc frame (1), a second disc frame (2), a third disc frame (3), a support (4), a belt pulley (5), a tightening rod (7), a shifting rod (8), a ball (9), a cushion block (10), a first spring (101) and a second spring (102), wherein the first disc frame (1) is installed on the support (4), the second disc frame (2) and the third disc frame (3) are installed on a main shaft (14), the first disc frame (1), the second disc frame (2) and the third disc frame (3) are concentric circles, the main shaft (14) is a part on the first disc frame (1), the main shaft (14) and the first disc frame (1) move synchronously, the belt pulley (5) is installed on the main shaft (14), during work, power is transmitted to the belt pulley (5), the belt pulley (5) drives the main shaft (14) to rotate, the main shaft (14) drives the first disc frame (1) to rotate, the driving lever (8) is driven to rotate, when the driving lever (8) is driven to the position of the cushion block (10), the driving lever (8) abuts against the second disk rack (2) to drive the second disk rack (2) to rotate, and when the driving lever (8) continues to rotate, the driving lever (8) leaves the cushion block (10), and the driving lever (8) does not abut against the second disk rack (2) any more.

2. The constant force transmission device according to claim 1, wherein: the disc frame I (1) mainly comprises a disc I (11), a deflector rod mounting hole (12), a spring II mounting position (13), a main shaft (14), a main shaft key groove (15) and a belt pulley locking screw hole (16), wherein the disc I (11) and the main shaft (14) are in a concentric relation, the concentricity means that the central line of the disc I (1) and the central line of the main shaft (14) are superposed, the deflector rod mounting hole (12) is positioned on the disc I (11), the deflector rod mounting hole (12) is a through hole and used for mounting a deflector rod (8), the spring II mounting position (13) and the deflector rod mounting hole (12) are concentric, the aperture of the spring II mounting position (13) is larger than the outer diameter of a deflector rod body (81) and also larger than the outer diameter of the spring II (102), the spring II mounting position (13) is used for mounting the spring II (102), the main shaft key groove (15) is positioned on the main shaft (14), and the main shaft key groove (15) is matched with the belt pulley (5), the locking device is used for placing a pin key and preventing the belt pulley (5) from rotating on the main shaft (14), the belt pulley locking screw hole (16) is a threaded hole, and the belt pulley (5) is prevented from falling off from the main shaft (14) by a screw and a gasket.

3. The constant force transmission device according to claim 1, wherein: the disc frame II (2) mainly comprises a disc frame II center hole (21), a disc frame II bearing position (22), an end cover II locking hole (23), a poking rod position (24) and a butting rod butting hole (25), the aperture of the disc frame II center hole (21) is larger than the outer diameter of the main shaft (14), the disc frame II center hole (21) penetrates through the main shaft (14), the disc frame II bearing position (22) is used for installing a bearing, the bearing is installed on the main shaft (14), therefore, the disc frame II (2) can freely rotate on the main shaft (14), the end cover II locking hole (23) is a threaded hole, the disc frame II end cover (62) is locked on the disc frame II (2) by a screw rod to prevent the bearing from loosening, the poking rod position (24) is a conical groove, the poking rod position (24) takes the circle center of the disc frame II (2) as a reference point, and is distributed on the disc frame II (2) in a circumferential array manner, the distribution quantity of the poking rod positions (24) determines the gear ratio of the constant-force speed change device, the abutting rod abutting holes (25) are located on the back face of the poking rod positions (24), the quantity corresponds to the poking rod positions (24), and the abutting rod abutting holes (25) are conical grooves.

4. The constant force transmission device according to claim 1, wherein: the disc frame III (3) mainly comprises a tightening rod mounting hole (31), a spring mounting position (32), a disc frame III locking hole (33) and a disc frame III center hole (34), the tightening rod mounting hole (31) is distributed on the disc frame III (3) in a circumferential array by taking the circle center of the disc frame III (3) as a reference point, the number of the tightening rod mounting holes (31) corresponds to that of the shift lever positions (24), the tightening rod mounting hole (31) is a through hole for mounting a tightening rod (7), the spring mounting position (32) is concentric with the tightening rod mounting hole (31), the inner diameter of the spring mounting position (32) is larger than that of the tightening rod mounting hole (31), the spring mounting position (32) is used for mounting a spring I (101), the disc frame III locking hole (33) is distributed in a circumferential array by taking the center line of the disc frame III (3) as a reference point, and a screw passes through the disc frame III locking hole (33), the disc frame III (3) is locked on the bracket, and the aperture of the central hole (34) of the disc frame III is larger than the outer diameter of the main shaft (14), so that the main shaft (14) can rotate conveniently.

5. The constant force transmission device according to claim 1, wherein: the support (4) mainly comprise a support bearing hole (41), an end cover hole (42), a support fixing hole (43), a cushion block mounting hole (44), a support end cover locking hole (45) and a support center hole (46), wherein the support bearing hole (41) is used for mounting a bearing, a main shaft (14) is mounted on the bearing, the end cover hole (42) is a recessed hole and is used for mounting a support end cover (61), the support fixing hole (43) utilizes a screw rod to fix the whole constant-force speed change device, the cushion block mounting hole (44) is used for mounting a cushion block (10), the support end cover locking hole (45) utilizes the screw rod to lock the support end cover (61) on the support (4) so as to prevent the bearing from loosening, and the support center hole (46) is used for penetrating through the main shaft (14).

6. The constant force transmission device according to claim 1, wherein: support tight pole (7) mainly by supporting tight pole annular position (71), support tight pole body (72) and constitute, support tight pole annular position (71) external diameter and be greater than supporting tight pole body (72) external diameter, spring (101) are inserted and are supported tight pole body (72), owing to support the existence of tight pole annular position (71), spring (101) just can play a role, support tight pole (7) front end is conical to with support tight pole support hole (25) tapering is the same, support the process when tight pole (7) give way to the back: when the disc frame (1) drives the disc frame (2) to rotate, the abutting rod abuts against the hole (25) to rotate along with the hole, because the abutting rod abuts against the hole (25) to be a conical groove, when the torque when the disc frame (1) rotates is greater than the elastic force of the spring (101), the spring (101) is compressed, the abutting rod (7) retreats, and the abutting rod (7) abuts against the process to be: when the front end of the abutting rod (7) is located in the range of the abutting rod abutting hole (25), the first spring (101) acts to abut the abutting rod (7) against the abutting rod abutting hole (25), and due to the conical positioning effect, the distance that the second disc frame (2) moves at each time is guaranteed to be consistent.

7. The constant force transmission device according to claim 1, wherein: the shifting lever (8) mainly comprises a shifting lever key groove (81), a spring C mounting position (82) and a ball mounting position (83), wherein a shifting lever body (81) is inserted into a shifting lever mounting hole (12), the shifting lever body (81) is used for inserting a spring II (102), the spring III mounting position (82) is used for mounting a spring III (103), and the ball mounting position (83) is used for mounting a ball (9)

The process when the deflector rod (8) is tightly propped: when power is transmitted to the disc frame I (1), the disc frame I (1) rotates, the support is fixed, the disc frame I (1) drives the shifting rod (8) to rotate together, when the shifting rod (8) runs to the position of the cushion block (10), the spring III (103) retreats, the ball (9) retreats along with the shifting, at the moment, if the moment when the disc frame I (1) rotates is larger than the elastic force of the spring II (102), the spring II (102) retracts, the shifting rod (8) retreats and moves onto the cushion block (10), the rear end of the shifting rod body (81) is conical, the conical degree of the conical shape is the same as that of the shifting rod position (24), the rear end of the shifting rod body (81) abuts against the shifting rod position (24), and the shifting rod (8) continues to move forwards on the cushion block (10), and the shifting rod (8) drives the disc frame II (2) to rotate;

the process when the shift lever (8) is loosened is as follows: when the shifting lever (8) leaves the cushion block (10), the spring III (103) advances, the ball (9) advances along with the advance, at the moment, the spring II (102) advances to drive the rear end of the shifting lever body (81) to leave the shifting lever position (24), the disc frame I (1) continues to rotate, but the disc frame II (2) cannot rotate until the shifting lever (8) tightly abuts against the cushion block (10) again, and the process when the shifting lever (8) tightly abuts against is repeated.

8. The constant force transmission device according to claim 1, wherein: the cushion block (10) mainly comprises an inclined plane (1001) and a cushion block hole (1002), the cushion block hole (1002) and the cushion block mounting hole (44) are in corresponding relation, the cushion block (10) is fixed on the support (4) through a screw rod, the inclined plane is a 20-45-degree inclined plane formed by two sides of the cushion block, and the thickness of the cushion block (10) is 2-5 mm greater than the depth of the poking rod position (24).