阅读说明：本技术 一种闭环伺服无级变速器 (Closed-loop servo continuously variable transmission ) 是由 不公告发明人 于 2021-01-04 设计创作，主要内容包括：本发明公开一种闭环伺服无级变速器,包括外壳、中心齿轮、内齿圈、行星齿轮、行星架、输出轴、第一传动锥轮、第二传动锥轮、输入轴,外壳是支撑主体,输入轴与外壳构成转动副,并驱动第一传动锥轮旋转,第一传动锥轮通过由滑动架、第一保持杆、从动轮、从动齿轮、第二保持杆、传动齿轮、驱动轮、驱动齿轮、保持片构成的传动装置驱动第二传动锥轮旋转,第二传动锥轮通过中心齿轮和三个行星齿轮驱动输出轴转动,气缸用于控制第一传动锥轮与第二传动锥轮之间传动的通断,气缸推力由控制系统进行闭环伺服控制,电机通过旋转螺纹杆改变滑动架的位置,从而改变第一传动锥轮与第二传动锥轮之间的传动比,实现输入轴与输出轴之间的无级变速。(The invention discloses a closed-loop servo stepless speed changer, which comprises a shell, a central gear, an inner gear ring, planetary gears, a planet carrier, an output shaft, a first transmission cone pulley, a second transmission cone pulley and an input shaft, wherein the shell is a supporting body, the input shaft and the shell form a rotating pair and drive the first transmission cone pulley to rotate, the first transmission cone pulley drives the second transmission cone pulley to rotate through a transmission device consisting of a sliding frame, a first retaining rod, a driven wheel, a driven gear, a second retaining rod, a transmission gear, a driving wheel, a driving gear and a retaining sheet, the second transmission cone pulley drives the output shaft to rotate through the central gear and three planetary gears, a cylinder is used for controlling the on-off of transmission between the first transmission cone pulley and the second transmission cone pulley, the thrust of the cylinder is subjected to closed-loop servo control by a control system, a motor changes the position of the sliding frame through rotating a threaded rod so as to change the transmission ratio between the first transmission cone pulley and the second, realizing the stepless speed change between the input shaft and the output shaft.)

1. A closed loop servo continuously variable transmission comprises a shell (1), a fourth gear (2), a central shaft (3), a central gear (4), an inner gear ring (5), a planetary gear (6), a planet carrier (7), an output shaft (8), a threaded rod (9), a motor (10), a third gear (11), a second transmission bevel gear (12), a first transmission bevel gear (13), a second bevel gear (14), a first bevel gear (15), an input shaft (16), a sealing cover (17), a sliding frame (18), a cylinder (19), a first retaining rod (20), a driven wheel (21), a driven gear (21.1), a second retaining rod (22), a transmission gear (22.1), a driving wheel (23), a driving gear (23.1) and a retaining sheet (24), and is characterized in that: the shell (1) is a supporting body, the input shaft (16) and the shell (1) form a rotating pair, and the input shaft and the shell (1) drive a first transmission cone pulley (13) to rotate through a first bevel gear (15) and a second bevel gear (14), the first transmission cone pulley (13) drives a second transmission cone pulley (12) to rotate through a transmission device consisting of a sliding frame (18), a first retaining rod (20), a driven wheel (21), a driven gear (21.1), a second retaining rod (22), a transmission gear (22.1), a driving wheel (23), a driving gear (23.1) and a retaining sheet (24), the second transmission cone pulley (12) drives a central shaft (3) and a central gear (4) to rotate through a third gear (11) and a fourth gear (2), the central gear (4) drives an output shaft (8) to rotate through three planetary gears (6), and an air cylinder (19) is used for controlling the on-off of transmission between the first transmission cone pulley (13) and the second transmission cone pulley (12), the motor (10) is arranged on the sealing cover (17), and the position of the sliding frame (18) is changed by rotating the threaded rod (9), so that the transmission ratio between the first transmission cone pulley (13) and the second transmission cone pulley (12) is steplessly changed, and the stepless speed change between the input shaft (16) and the output shaft (8) is realized.

2. A closed loop servo continuously variable transmission as claimed in claim 1, wherein: the shell (1) is a support main body of the transmission, four guide rails are obliquely arranged on two side walls in the shell, a sealing cover (17) is fixedly arranged on the left side of the shell (1) through screws, an input shaft (16) is arranged on the upper side of the shell (1) and forms a rotating pair with the shell (1) through three bearings, a first bevel gear (15) is coaxially and fixedly connected with the lower end of the input shaft (16), a central shaft (3) is arranged in the shell (1) and forms a rotating pair with the shell (1) through two bearings, a fourth gear (2) is coaxially and fixedly connected with the left end of the central shaft (3), a central gear (4) is coaxially and fixedly connected with the right end of the central shaft (3), an inner gear ring (5) is fixedly arranged in the shell (1), an output shaft (8) forms a rotating pair with the right end of the shell (1) through two bearings, and a planet carrier (, three short shafts are uniformly distributed on the left side of the planet carrier (7) in the circumferential direction, each short shaft is rotatably provided with a planetary gear (6), the three planetary gears (6) are arranged between the central gear (4) and the inner gear ring (5) and form a gear engagement relation with the central gear (4) and the inner gear ring (5), and therefore the central gear (4), the inner gear ring (5), the planet carrier (7) and the three planetary gears (6) form a planetary gear train;

the first transmission cone pulley (13) is arranged in the shell (1) and forms a revolute pair, the big end of the first transmission cone pulley (13) is arranged towards the left and the small end of the first transmission cone pulley is arranged towards the right, the generatrix on the upper side of the conical surface of the first transmission cone pulley (13) is parallel to four guide rails in the shell (1), the second bevel gear (14) is coaxially and tightly connected with the left end of the first transmission cone pulley (13), the second bevel gear (14) and the first bevel gear (15) form gear meshing transmission, the second transmission cone pulley (12) is arranged in the shell (1) and forms a revolute pair, the big end is right, the small end is left, the second transmission cone pulley (12) is positioned above the first transmission cone pulley (13), a bus at the lower side of the shell is parallel to four guide rails in the shell (1), a third gear (11) is coaxially and fixedly connected with the right end of a second transmission bevel wheel (12), and the third gear (11) and a fourth gear (2) form gear meshing transmission;

the sliding frame (18) is arranged inside the shell (1), two sliding block structures arranged at the left end and two sliding block structures arranged at the right end of the sliding frame (18) are respectively matched and arranged with four guide rails on two side walls inside the shell (1), so that the sliding frame (18) and the shell (1) form a moving pair, a threaded hole (18.1) is arranged at the position, close to the left end, of the sliding frame (18), a round hole (18.2) and a long slotted hole (18.3) are arranged at the position, close to the middle of the sliding frame (18), of the sliding frame, a second retaining rod (22) is arranged in the round hole (18.2) to form a rotating pair, two transmission gears (22.1) are respectively and coaxially and fixedly arranged at two ends of the second retaining rod (22), a first retaining rod (20) can slide in the long slotted hole (18.3), a driving wheel (23) is positioned at the lower side between the first retaining rod (20) and the second retaining rod, two ends of a driving wheel (23) are rotatably connected with a first retaining rod (20) through two retaining pieces (24), two ends of the driving wheel (23) are further rotatably connected with a second retaining rod (22) through the two retaining pieces (24), so that the driving wheel (23.1) is always meshed with a transmission gear (22.1), a driven wheel (21) is positioned on the upper side between the first retaining rod (20) and the second retaining rod (22), two driven gears (21.1) are coaxially and fixedly arranged at two ends of the driven wheel (21) respectively, two ends of the driven wheel (21) are rotatably connected with the first retaining rod (20) through the two retaining pieces (24), and two ends of the driven wheel (21) are also rotatably connected with the second retaining rod (22) through the two retaining pieces (24), so that the driven gear (21.1) is always meshed with the transmission gear (22.1);

the rear end of the motor (10) is fixedly arranged on the right side of the sealing cover (17) through a screw, an output shaft of the motor (10) is fixedly connected with a threaded rod (9), the threaded rod (9) and a threaded hole (18.1) are matched and arranged to form threaded transmission, the motor (10) rotates through driving the threaded rod (9) to change the position of the sliding frame (18), the left end of the air cylinder (19) and the first retaining rod (20) form a rotating pair, and the right end of the air cylinder (19) is fixedly connected with the right end of the sliding frame (18);

in an initial state, the air cylinder (19) extends and pushes the first retaining rod (20) to slide leftwards in the long slotted hole (18.3), under the thrust action of the eight retaining pieces (24), the driving wheel (23) moves downwards and is tightly attached to an upper side bus of the first transmission cone pulley (13), and the driven wheel (21) moves upwards and is tightly attached to a lower side bus of the second transmission cone pulley (12).

3. A closed loop servo continuously variable transmission as claimed in claim 1, wherein: after a power drive input shaft (16) from an engine or a motor rotates, a first bevel gear (15) drives a first transmission bevel gear (13) to rotate through a second bevel gear (14), the first transmission bevel gear (13) drives a driving wheel (23) and a driving wheel (23.1) to rotate through friction force, the driving wheel (23.1) drives a driven gear (21.1) and a driven wheel (21) to rotate through a gear meshing relationship between the driving gear (22.1) and the driven gear (21.1), the driven wheel (21) drives a second transmission bevel gear (12) and a third gear (11) to rotate through a friction transmission relationship with a bus at the lower side of the second transmission bevel gear (12), the third gear (11) drives a central shaft (3) and a central gear (4) to rotate through a fourth gear (2), and the central gear (4) drives an output shaft (8) to rotate through three planetary gears (6) and a planet carrier (7), the output shaft (8) transmits the power to wheels or other actuating mechanisms;

when the speed change is needed, firstly, the air cylinder (19) contracts and pulls the first holding rod (20) to move rightwards, under the tension of the eight retaining pieces (24), the driving wheel (23) moves upwards and is separated from contact with an upper bus of the first transmission cone pulley (13), the driven wheel (21) moves downwards and is separated from contact with a lower bus of the second transmission cone pulley (12), then the motor (10) moves the sliding frame (18) to a proper transmission ratio position through the threaded rod (9), the cylinder (19) extends and pushes the first holding rod (20) to move leftward, under the thrust action of the eight retaining pieces (24), the driving wheel (23) moves downwards and is in contact with and pressed against an upper side bus of the first transmission cone pulley (13), and the driven wheel (21) moves upwards and is in contact with and pressed against a lower side bus of the second transmission cone pulley (12), so that the speed change action is completed; the carriage (18) has a minimum gear ratio at the left end of its travel and the carriage (18) has a maximum gear ratio at the right end of its travel;

the pressure between the driving wheel (23) and the first transmission conical wheel (13) and the pressure between the driven wheel (21) and the second transmission conical wheel (12) depend on the thrust of the air cylinder (19), the thrust of the air cylinder (19) is controlled by the air pressure in the air cylinder, and the air pressure is controlled in a closed-loop servo mode by a control system; when the output torque of the engine or the motor is increased, the control system increases air pressure to increase the thrust of the air cylinder (19), so that the pressure between the driving wheel (23) and the first transmission cone pulley (13) and the pressure between the driven wheel (21) and the second transmission cone pulley (12) are increased, and the torque which can be transmitted by the transmission is increased; when the output torque of the engine or the motor is reduced, the control system reduces the air pressure, so that the thrust of the air cylinder (19) is reduced, the pressure between the driving wheel (23) and the first transmission conical wheel (13) and the pressure between the driven wheel (21) and the second transmission conical wheel (12) are reduced, the periodic elastic deformation of the driving wheel (23) and the driven wheel (21) is reduced, and the service life of the transmission is prolonged.

Technical Field

The invention relates to the field of transmissions, in particular to a closed-loop servo stepless transmission.

Background

The mechanical stepless speed changer has the advantages of simple structure, high reliability, convenient stepless speed regulation and the like, and is mostly applied to cone pulley type, belt type and the like at present; the belt-driven continuously variable transmission mainly realizes stepless change of the speed ratio by reducing main and driven gears and metal belts, has high transmission efficiency and wider speed change range, thereby obtaining the optimal matching of a transmission system and the working condition of an engine and improving the fuel economy of the whole vehicle; in the last decade, cvt (continuously Variable transmission) technology has made great progress and is widely used in the field of low-power automobiles, but it is limited by metal belt materials and technologies, making the manufacturing cost very high, and its core technology and patents are mostly mastered in foreign enterprises, and national enterprises are in obvious disadvantage in developing belt-driven continuously Variable transmissions; the cone pulley type stepless speed changer mainly drives by the driving rigid element, the driven rigid element and the intermediate transmission piece through contact friction and lubricating oil film traction, and can carry out stepless speed change by changing the working radius of the contact part of the cone pulley type stepless speed changer, and has the advantages of stable transmission, low noise, simple structure, overload protection effect, various forms and the like; the development of the cone pulley type continuously variable transmission with reasonable function, stability and reliability has obvious economic benefit and social significance.

Chinese patent publication No. CN106090161A discloses a servo cone pulley type continuously variable transmission with a small friction pulley capable of moving linearly in the middle, and the position of the small friction pulley is changed to change the transmission ratio between an input cone pulley and an output cone pulley, thereby realizing continuously variable transmission; because the small friction wheel is in transmission with the input cone pulley and the output cone pulley through friction force, the small friction wheel inevitably has sliding friction with contact buses of the input cone pulley and the output cone pulley in the speed changing process, the contact surfaces of the small friction wheel and the input cone pulley and the output cone pulley are extremely easy to damage, the service life of the transmission is seriously shortened, and the sliding friction can also generate more heat, wastes more fuel, aggravates atmospheric pollution and also reduces the transmission efficiency of the transmission.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention aims to provide a closed-loop servo continuously variable transmission which is novel in structure, small in occupied space and capable of effectively prolonging the service life of a cone pulley type continuously variable transmission.

The technical scheme adopted by the invention is as follows: a closed-loop servo continuously variable transmission comprising a housing, a fourth gear, a center shaft, a center gear, an inner gear ring, a planetary gear, a planet carrier, an output shaft, a threaded rod, a motor, a third gear, a second transmission cone, a first transmission cone, a second cone, a first cone, an input shaft, a seal cover, a carriage, a cylinder, a first retaining rod, a driven wheel, a driven gear, a second retaining rod, a transmission gear, a driving wheel, a driving gear, a retaining piece, characterized in that: the shell is a supporting body, the input shaft and the shell form a rotating pair, the input shaft and the shell drive a first transmission bevel wheel to rotate through a first bevel gear and a second bevel gear, the first transmission bevel wheel drives a second transmission bevel wheel to rotate through a transmission device which is composed of a sliding frame, a first retaining rod, a driven wheel, a driven gear, a second retaining rod, a transmission gear, a driving wheel, a driving gear and a retaining sheet, the second transmission bevel wheel drives a central shaft and a central gear to rotate through a third gear, a fourth gear, the central gear drives an output shaft to rotate through three planetary gears, a cylinder is used for controlling the on-off of transmission between the first transmission bevel wheel and the second transmission bevel wheel, a motor is arranged on a sealing cover, and the position of the sliding frame is changed through rotating a threaded rod, therefore, the transmission ratio between the first transmission cone pulley and the second transmission cone pulley is steplessly changed, and the stepless speed change between the input shaft and the output shaft is realized.

Preferably, the housing is a supporting body of the transmission, four guide rails are obliquely arranged on two side walls of the housing, the sealing cover is tightly mounted on the left side of the housing through screws, the input shaft is mounted on the upper side of the housing and forms a rotation pair with the housing through three bearings, the first bevel gear is coaxially and tightly connected with the lower end of the input shaft, the central shaft is mounted in the housing and forms a rotation pair with the housing through two bearings, the fourth gear is coaxially and tightly connected with the left end of the central shaft, the central gear is coaxially and tightly connected with the right end of the central shaft, the inner gear ring is fixedly mounted in the housing, the output shaft forms a rotation pair with the right end of the housing through two bearings, the planet carrier is coaxially and tightly connected with the left end of the output shaft, three short shafts are uniformly distributed on, and the central gear, the inner gear ring, the planet carrier and the three planetary gears form a planetary gear train.

Preferably, the first transmission bevel wheel is installed inside the shell to form a revolute pair, the large end of the first transmission bevel wheel faces to the left and the small end of the first transmission bevel wheel faces to the right, a bus on the upper side of a conical surface of the first transmission bevel wheel is parallel to four guide rails inside the shell, the second transmission bevel wheel is coaxially and fixedly connected with the left end of the first transmission bevel wheel, the second transmission bevel wheel forms gear meshing transmission with the first bevel wheel, the second transmission bevel wheel is installed inside the shell to form a revolute pair, the large end of the second transmission bevel wheel faces to the left and the small end of the second transmission bevel wheel is located above the first transmission bevel wheel, a bus on the lower side of the second transmission bevel wheel is parallel to four guide rails inside the shell, the third gear is coaxially and fixedly connected with.

Preferably, the sliding frame is arranged in the shell, the two sliding block structures arranged at the left end of the sliding frame and the two sliding block structures arranged at the right end of the sliding frame are respectively matched and arranged with four guide rails on two side walls in the shell, so that the sliding frame and the shell form a moving pair, the sliding frame is provided with a threaded hole close to the left end, a round hole and a long slotted hole are arranged close to the middle position, the second retaining rod is arranged in the round hole to form a rotating pair, the two transmission gears are respectively and coaxially and tightly arranged at two ends of the second retaining rod, the first retaining rod can slide in the long slotted hole, the driving wheel is positioned at the lower side between the first retaining rod and the second retaining rod, the two driving gears are respectively and coaxially and tightly arranged at two ends of the driving wheel, two ends of the driving wheel are rotatably connected with the first retaining rod through the two retaining pieces, the driven wheel is positioned on the upper side between the first retaining rod and the second retaining rod, the two driven gears are respectively and coaxially and fixedly arranged at two ends of the driven wheel, two ends of the driven wheel are rotatably connected with the first retaining rod through the two retaining pieces, and two ends of the driven wheel are also rotatably connected with the second retaining rod through the two retaining pieces, so that the driven gears are always meshed with the transmission gear.

Preferably, the rear end of the motor is fixedly mounted on the right side of the sealing cover through a screw, an output shaft of the motor is fixedly connected with a threaded rod, the threaded rod and the threaded hole are matched and mounted to form threaded transmission, the motor rotates to change the position of the sliding frame through driving the threaded rod, the left end of the air cylinder and the first retaining rod form a rotating pair, and the right end of the air cylinder is fixedly connected with the right end of the sliding frame.

In an initial state, the cylinder extends and pushes the first holding rod to slide leftwards in the long slot hole, the driving wheel moves downwards and is tightly attached to the upper side generatrix of the first transmission cone pulley, and the driven wheel moves upwards and is tightly attached to the lower side generatrix of the second transmission cone pulley under the action of thrust of the eight holding pieces.

After the power from an engine or a motor drives an input shaft to rotate, a first bevel gear drives a first transmission bevel gear to rotate through a second bevel gear, the first transmission bevel gear drives a driving wheel and a driving gear to rotate through friction force, the driving gear drives a driven gear and a driven gear to rotate through a gear meshing relationship between the driving gear and the driven gear, the driven gear drives a second transmission bevel gear and a third gear to rotate through a relationship of friction transmission with a bus at the lower side of the second transmission bevel gear, the third gear drives a central shaft and a central gear to rotate through a fourth gear, the central gear drives an output shaft to rotate through three planetary gears and a planetary carrier, and the output shaft transmits power to wheels or other execution mechanisms.

When speed change is needed, firstly, the cylinder contracts and pulls the first retaining rod to move rightwards, under the action of the pulling force of the eight retaining pieces, the driving wheel moves upwards and is separated from contact with an upper side bus of the first transmission conical wheel, the driven wheel moves downwards and is separated from contact with a lower side bus of the second transmission conical wheel, then the motor enables the sliding frame to move to a proper transmission ratio position through the threaded rod, the cylinder extends and pushes the first retaining rod to move leftwards, under the action of the pushing force of the eight retaining pieces, the driving wheel moves downwards and is contacted with and pressed against the upper side bus of the first transmission conical wheel, the driven wheel moves upwards and is contacted with and pressed against the lower side bus of the second transmission conical wheel, and therefore speed change action is completed; the slide carriage has a minimum transmission ratio at the left end of its stroke and a maximum transmission ratio at the right end of its stroke.

The pressure between the driving wheel and the first transmission cone pulley and the pressure between the driven wheel and the second transmission cone pulley depend on the thrust of the air cylinder, the thrust of the air cylinder is controlled by the air pressure in the air cylinder, and the air pressure is controlled by a control system in a closed-loop servo mode; when the output torque of the engine or the motor is increased, the control system increases air pressure to increase the thrust of the air cylinder, so that the pressure between the driving wheel and the first transmission conical wheel and the pressure between the driven wheel and the second transmission conical wheel are increased, and the transmittable torque of the transmission is increased; when the output torque of the engine or the motor is reduced, the control system reduces the air pressure to reduce the thrust of the air cylinder, so that the pressure between the driving wheel and the first transmission cone pulley and the pressure between the driven wheel and the second transmission cone pulley are reduced, the periodic elastic deformation of the driving wheel and the driven wheel is reduced, and the service life of the transmission is prolonged.

The invention has the beneficial effects that:

firstly, the driving wheel is separated from contact with the first transmission bevel wheel, the driven wheel is separated from contact with the second transmission bevel wheel, and then the positions of the driving wheel and the driven wheel are moved, so that the defects that the surfaces of the bevel wheels and the speed regulating wheels are scratched and slipped when the middle speed regulating wheel and the two bevel wheels move in a contact state when the traditional bevel wheel type stepless speed regulating structure regulates speed are overcome, and the service life of the transmission is greatly prolonged;

the contact pressure between the driving wheel and the first transmission bevel wheel and the contact pressure between the driven wheel and the second transmission bevel wheel can be subjected to closed-loop servo control by the control system according to the input torque, the contact pressure is increased when the input torque is increased so as to improve the transferable torque of the transmission, and the contact pressure is reduced when the input torque is reduced so as to prolong the service life of the transmission;

the speed changer adopts a planetary gear train speed reducing structure, and has the advantages of large transmission ratio, small volume, stable transmission, high transmission efficiency, uniform load distribution among gear teeth, strong shock and vibration resistance and the like;

the structure is compact, the occupied space is small, the volume and the weight of the whole vehicle or equipment can be effectively reduced, and the energy conservation and emission reduction are facilitated.

Drawings

Fig. 1 is a schematic diagram of the overall structure of the transmission.

Fig. 2 is a schematic longitudinal sectional view of the transmission.

Fig. 3 is a schematic longitudinal sectional view of the transmission.

Fig. 4 is a partial schematic view of the shifting mechanism.

Fig. 5 is a schematic diagram of a transmission in an oblique cross-sectional configuration.

Fig. 6 is a schematic diagram of a transmission in an oblique cross-sectional configuration.

Fig. 7 is an exploded schematic view of the transmission.

Fig. 8 is a schematic view of the sliding frame.

Reference numerals: the device comprises a shell 1, a fourth gear 2, a central shaft 3, a central gear 4, an annular gear 5, a planetary gear 6, a planet carrier 7, an output shaft 8, a threaded rod 9, a motor 10, a third gear 11, a second transmission bevel gear 12, a first transmission bevel gear 13, a second bevel gear 14, a first bevel gear 15, an input shaft 16, a sealing cover 17, a sliding frame 18, a threaded hole 18.1, a round hole 18.2, a slotted hole 18.3, an air cylinder 19, a first retaining rod 20, a driven wheel 21, a driven gear 21.1, a second retaining rod 22, a transmission gear 22.1, a driving wheel 23, a driving gear 23.1 and a retaining piece 24.

Detailed Description

The invention will be further described with reference to the drawings and specific embodiments, which are illustrative of the invention and are not to be construed as limiting the invention.

As shown in fig. 1 to 8, a closed-loop servo continuously variable transmission includes a housing 1, a fourth gear 2, a center shaft 3, a sun gear 4, an internal gear 5, a planetary gear 6, a carrier 7, an output shaft 8, a threaded rod 9, a motor 10, a third gear 11, a second transmission bevel gear 12, a first transmission bevel gear 13, a second transmission bevel gear 14, a first bevel gear 15, an input shaft 16, a seal cover 17, a carriage 18, a cylinder 19, a first holding rod 20, a driven wheel 21, a driven gear 21.1, a second holding rod 22, a transmission gear 22.1, a driving wheel 23, a driving gear 23.1, and a holding plate 24, and is characterized in that: the housing 1 is a supporting body, the input shaft 16 and the housing 1 form a rotation pair, and drives the first transmission cone pulley 13 to rotate through a first bevel gear 15 and a second bevel gear 14, the first transmission cone pulley 13 drives the second transmission cone pulley 12 to rotate through a transmission device formed by a sliding frame 18, a first holding rod 20, a driven pulley 21, a driven gear 21.1, a second holding rod 22, a transmission gear 22.1, a driving wheel 23, a driving gear 23.1 and a holding sheet 24, the second transmission cone pulley 12 drives the central shaft 3 and the central gear 4 to rotate through a third gear 11 and a fourth gear 2, the central gear 4 drives the output shaft 8 to rotate through three planetary gears 6, the air cylinder 19 is used for controlling the on-off of the transmission between the first transmission cone pulley 13 and the second transmission cone pulley 12, the motor 10 is mounted on a sealing cover 17, and the position of the sliding frame 18 is changed through rotating the threaded rod 9, so that the transmission ratio between the first transmission cone pulley 13 and the second transmission cone pulley 12 is steplessly changed, a stepless speed change between the input shaft 16 and the output shaft 8 is achieved.

The shell 1 is a supporting main body of the speed changer, four guide rails are obliquely arranged on two side walls inside the shell, a sealing cover 17 is tightly installed on the left side of the shell 1 through screws, an input shaft 16 is installed on the upper side of the shell 1 and forms a rotation pair with the shell 1 through three bearings, a first bevel gear 15 is coaxially and tightly connected with the lower end of the input shaft 16, a central shaft 3 is installed inside the shell 1 and forms a rotation pair with the shell 1 through two bearings, a fourth gear 2 is coaxially and tightly connected with the left end of the central shaft 3, a central gear 4 is coaxially and tightly connected with the right end of the central shaft 3, an inner gear ring 5 is fixedly installed inside the shell 1, an output shaft 8 forms a rotation pair with the right end of the shell 1 through two bearings, a planet carrier 7 is coaxially and tightly connected with the left end of the output, the three planetary gears 6 are mounted between the sun gear 4 and the ring gear 5, and are in gear engagement with the latter two, so that the sun gear 4, the ring gear 5, the planet carrier 7 and the three planetary gears 6 constitute a planetary gear train.

The first transmission bevel wheel 13 is arranged inside the shell 1 and forms a revolute pair, the large end of the first transmission bevel wheel is arranged towards the left and the small end of the first transmission bevel wheel is arranged towards the right, a generatrix on the upper side of a conical surface of the first transmission bevel wheel 13 is parallel to four guide rails inside the shell 1, the second bevel gear 14 is coaxially and fixedly connected with the left end of the first transmission bevel wheel 13, the second bevel gear 14 and the first bevel gear 15 form gear meshing transmission, the second transmission bevel wheel 12 is arranged inside the shell 1 and forms a revolute pair, the large end of the first transmission bevel wheel is arranged towards the right and the small end of the second transmission bevel wheel is arranged towards the left, the second transmission bevel wheel 12 is arranged above the first transmission bevel wheel 13, the generatrix on the lower side of the second transmission bevel wheel is parallel to four guide rails inside the shell 1.

The sliding frame 18 is installed inside the casing 1, two sliding block structures arranged at the left end and two sliding block structures arranged at the right end of the sliding frame 18 are respectively installed in a matching way with four guide rails on two side walls inside the casing 1, so that the sliding frame 18 and the casing 1 form a moving pair, the sliding frame 18 is provided with a threaded hole 18.1 near the left end, a round hole 18.2 and a long slotted hole 18.3 near the middle position, a second retaining rod 22 is installed in the round hole 18.2 to form a rotating pair, two transmission gears 22.1 are respectively and coaxially and tightly installed at two ends of the second retaining rod 22, the first retaining rod 20 can slide in the long slotted hole 18.3, a driving wheel 23 is positioned at the lower side between the first retaining rod 20 and the second retaining rod 22, two driving gears 23.1 are respectively and coaxially and tightly installed at two ends of the driving wheel 23, two ends of the driving wheel 23 are rotatably connected with the first retaining rod 20 through two retaining pieces 24, and two ends of the, the driving gear 23.1 is always meshed with the transmission gear 22.1, the driven wheel 21 is positioned on the upper side between the first retaining rod 20 and the second retaining rod 22, the two driven gears 21.1 are coaxially and fixedly arranged at two ends of the driven wheel 21 respectively, two ends of the driven wheel 21 are rotatably connected with the first retaining rod 20 through two retaining pieces 24, and two ends of the driven wheel 21 are also rotatably connected with the second retaining rod 22 through two retaining pieces 24, so that the driven gear 21.1 is always meshed with the transmission gear 22.1.

The rear end of the motor 10 is fixedly arranged on the right side of the sealing cover 17 through screws, an output shaft of the motor 10 is fixedly connected with a threaded rod 9, the threaded rod 9 is matched with a threaded hole 18.1 to be installed to form threaded transmission, the motor 10 rotates through driving the threaded rod 9 to change the position of the sliding frame 18, the left end of the air cylinder 19 and the first retaining rod 20 form a rotating pair, and the right end of the air cylinder 19 is fixedly connected with the right end of the sliding frame 18.

In the initial state, the cylinder 19 extends and pushes the first holding rod 20 to slide leftwards in the slotted hole 18.3, and under the thrust of the eight holding pieces 24, the driving wheel 23 moves downwards and is tightly attached to the upper generatrix of the first transmission cone wheel 13, and the driven wheel 21 moves upwards and is tightly attached to the lower generatrix of the second transmission cone wheel 12.

After the power from the engine or the motor drives the input shaft 16 to rotate, the first bevel gear 15 drives the first transmission bevel gear 13 to rotate through the second bevel gear 14, the first transmission bevel gear 13 enables the driving wheel 23 and the driving wheel 23.1 to rotate through friction force, the driving wheel 23.1 drives the driven wheel 21.1 and the driven wheel 21 to rotate through the gear meshing relationship between the driving gear 22.1 and the driven gear 21.1, the driven wheel 21 drives the second transmission bevel gear 12 and the third gear 11 to rotate through the friction transmission relationship with a bus on the lower side of the second transmission bevel gear 12, the third gear 11 drives the central shaft 3 and the central gear 4 to rotate through the fourth gear 2, the central gear 4 drives the output shaft 8 to rotate through the three planet gears 6 and the planet carrier 7, and the output shaft 8 transmits power to wheels or other execution mechanisms.

When speed change is required, firstly, the air cylinder 19 contracts and pulls the first holding rod 20 to move rightwards, under the action of the pulling force of the eight holding pieces 24, the driving wheel 23 moves upwards and is separated from contact with an upper side bus of the first transmission cone wheel 13, the driven wheel 21 moves downwards and is separated from contact with a lower side bus of the second transmission cone wheel 12, then the motor 10 enables the sliding frame 18 to move to a proper transmission ratio position through the threaded rod 9, the air cylinder 19 extends and pushes the first holding rod 20 to move leftwards, under the action of the pushing force of the eight holding pieces 24, the driving wheel 23 moves downwards and is contacted with and pressed against the upper side bus of the first transmission cone wheel 13, and the driven wheel 21 moves upwards and is contacted with and pressed against the lower side bus of the second transmission cone wheel 12, so that speed change action is completed; carriage 18 has the smallest gear ratio at the left end of its travel and carriage 18 has the largest gear ratio at the right end of its travel.

The pressure between the driving wheel 23 and the first transmission cone pulley 13 and the pressure between the driven wheel 21 and the second transmission cone pulley 12 depend on the thrust of the air cylinder 19, the thrust of the air cylinder 19 is controlled by the air pressure in the air cylinder 19, and the air pressure is controlled by a control system in a closed-loop servo mode; when the output torque of the engine or the motor is increased, the control system increases the air pressure to increase the thrust of the air cylinder 19, so that the pressure between the driving wheel 23 and the first transmission bevel wheel 13 and the pressure between the driven wheel 21 and the second transmission bevel wheel 12 are increased to increase the torque which can be transmitted by the transmission; when the output torque of the engine or the motor is reduced, the control system reduces the air pressure, so that the thrust of the air cylinder 19 is reduced, the pressure between the driving wheel 23 and the first transmission bevel wheel 13 and the pressure between the driven wheel 21 and the second transmission bevel wheel 12 are reduced, the periodic elastic deformation of the driving wheel 23 and the driven wheel 21 is reduced, and the service life of the transmission is prolonged.

The references to "front", "back", "left", "right", etc., are to be construed as references to orientations or positional relationships based on the orientation or positional relationship shown in the drawings or as orientations and positional relationships conventionally found in use of the product of the present invention, and are intended to facilitate the description of the invention and to simplify the description, but do not indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operated in a particular orientation, and is therefore not to be construed as limiting the invention. Furthermore, the terms "first," "second," and the like are used merely to distinguish one description from another, and are not to be construed as indicating or implying relative importance.