Continuously variable transmission, continuously variable transmission method and tractor

Abstract

The application provides a continuously variable transmission, a continuously variable transmission method and a tractor. The continuously variable transmission comprises a transmission input shaft connected with an engine, a first gear, a reverse gear clutch and a forward gear clutch installed on the transmission input shaft, a second gear connected with the reverse gear clutch, a third gear connected with the forward gear clutch, a generator connected with the first gear, a motor connected with the generator, a first shaft connected with the motor, a primary planetary gear set sun gear and a secondary planetary gear set sun gear installed on the first shaft, a second shaft sleeved on the first shaft, a fourth gear, a fifth gear and a first ring gear installed on the second shaft, the fourth gear connected with the second gear, the fifth gear engaged with the third gear, a planetary gear, a first double planetary gear and a second double planetary gear installed on a planet carrier, one end of a second ring gear engaged with the first double planetary gear, one end of a clutch connected with a transmission housing, and the other end of the second ring gear connected with the other end of the clutch.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gearbox, in particular to a continuously variable gearbox, continuously variable transmission method and tractor. BACKGROUND

[0002] At present, most of the existing tractor continuously variable gearbox adopts mechanical hydraulic shunt gearbox, but the hydraulic system efficiency is relatively low, the oil requirement is high, the maintenance is complex, and the use cost is high. SUMMARY

[0003] The technical problem to be solved by the present application is to provide a continuously variable gearbox, continuously variable transmission method and tractor to solve the problems of the prior art.

[0004] The technical scheme for solving the above technical problem is as follows: a continuously variable gearbox, comprising: an engine, a first gear, a reverse clutch, a second gear, a third gear, a forward clutch, a gearbox input shaft, a first inertia wheel, a generator, a second inertia wheel, a motor, a first shaft, a second shaft, a fourth gear, a fifth gear, a primary planetary gear sun gear, a first ring gear, a planetary gear, a second ring gear, a clutch, a gearbox housing, a carrier, a first double planetary gear, a second double planetary gear, and a secondary planetary gear sun gear, wherein one end of the gearbox input shaft is connected to the engine, the first gear, the reverse clutch and the forward clutch are all mounted on the gearbox input shaft, the second gear is connected to the reverse clutch, the third gear is connected to the forward clutch, the generator is connected to the first gear through the first inertia wheel, the motor is connected to the generator, one end of the first shaft is connected to the motor, the primary planetary gear sun gear and the secondary planetary gear sun gear are both mounted on the first shaft, the second shaft is sleeved on the outside of the first shaft, the fourth gear, the fifth gear and the first ring gear are all mounted on the second shaft, the fourth gear is connected to the second gear through the second inertia wheel, the fifth gear is engaged with the third gear, the planetary gear, the first double planetary gear and the second double planetary gear are all mounted on the carrier, one end of the second ring gear is engaged with the first double planetary gear, one end of the clutch is connected to the gearbox housing, and the other end of the second ring gear is connected to the other end of the clutch.

[0005] The beneficial effects of the technical scheme of the present application are: by designing a tractor mechanical and electrical power continuously variable transmission device, the problems of low transmission efficiency, complex maintenance, high oil requirement and high use cost of the existing CVT gearbox hydraulic transmission mechanism are solved. Using a motor drive has the advantages of high reliability, high efficiency and reduced energy consumption.

[0006] Further, the forward gear clutch comprises a forward 1st gear clutch and a forward 2nd gear clutch, the third gear is connected with the forward 1st gear clutch, the forward 2nd gear clutch is connected with a sixth gear, a seventh gear is arranged on the second shaft, and the seventh gear is engaged with the sixth gear.

[0007] The beneficial effects of the above further technical solutions are that the forward 1st gear clutch and the forward 2nd gear clutch are arranged, so that the corresponding clutches can be combined or separated according to actual needs, and the stability and reliability are improved.

[0008] Further, a seventh gear is arranged on the gearbox input shaft, the seventh gear is connected with a third idler, the third idler is connected with an auxiliary output shaft for driving a hydraulic pump.

[0009] The beneficial effects of the above further technical solutions are that the auxiliary output shaft is arranged for driving the hydraulic pump, and the power is reasonably utilized, so that the functions of the continuously variable transmission are diversified.

[0010] Further, a power output mechanism is connected to the other end of the gearbox input shaft.

[0011] The beneficial effects of the above further technical solutions are that the power output mechanism is arranged, so that the power transmission and application are facilitated.

[0012] Further, the second idler is connected with a third shaft.

[0013] The beneficial effects of the above further technical solutions are that the third shaft is arranged, so that the installation and maintenance of the second idler are facilitated.

[0014] Further, the generator is connected with a power battery, the power battery is connected with a power supply conversion device, and the power supply conversion device is connected with whole vehicle electrical components.

[0015] The beneficial effects of the above further technical solutions are that when the vehicle is running, part of the electricity generated by the generator is delivered to the motor, and the other part is stored in the power battery. The low-voltage power supply of the whole vehicle is converted from high voltage to low voltage by the power supply conversion device through the power battery, so as to supply power to the low-voltage components of the whole vehicle. The low-voltage generator of the whole vehicle can be omitted, and the use cost is reduced.

[0016] Further, the planet carrier is connected with a rear axle.

[0017] The beneficial effects of the above further technical solutions are that the rear axle is arranged, so that the power transmission and application are facilitated.

[0018] In addition, the application further provides a tractor comprising the continuously variable transmission.

[0019] In addition, the application further provides a continuously variable transmission method based on the continuously variable transmission device.

[0020] Starting the engine, rotating the transmission input shaft by the engine;

[0021] In the first stage of the forward gear: controlling the motor to rotate counterclockwise, combining the clutch, separating the reverse gear clutch, the forward 1st gear clutch and the forward 2nd gear clutch, rotating the planet carrier clockwise, and realizing the stepless speed change by controlling the rotating speed of the motor;

[0022] In the second stage of the forward gear: combining the forward 1st gear clutch, separating the reverse gear clutch, the forward 2nd gear clutch and the clutch, controlling the motor to reduce the rotating speed until the rotating speed is 0, controlling the motor to rotate clockwise, and realizing the stepless speed change;

[0023] In the third stage of the forward gear: separating the forward 1st gear clutch, the reverse gear clutch and the clutch, combining the forward 2nd gear clutch, adjusting the motor, and realizing the stepless speed change;

[0024] In the first stage of the reverse gear: controlling the motor to rotate clockwise, combining the clutch, separating the reverse gear clutch, the forward 1st gear clutch and the forward 2nd gear clutch, rotating the planet carrier counterclockwise, and realizing the stepless speed change by controlling the rotating speed of the motor;

[0025] In the second stage of the reverse gear: combining the reverse gear clutch, separating the forward 1st gear clutch, the forward 2nd gear clutch and the clutch, controlling the motor to reduce the rotating speed until the rotating speed is 0, controlling the motor to rotate counterclockwise, and realizing the stepless speed change.

[0026] The beneficial effects of the technical scheme of the application are as follows: the tractor mechanical and electrical power stepless speed change device is designed, the problems of the stepless speed change of the tractor and the low transmission efficiency, the complex maintenance, the high oil requirement and the high use cost of the existing CVT transmission device are solved, the motor is used for driving, the advantages of high reliability, high efficiency and reduced energy consumption are achieved, the pure electric stage and the mechanical and electrical power hybrid stage are realized, the purposes of saving oil, easy maintenance and stepless speed change in the interval are achieved.

[0027] Further, in the third stage of the forward gear, adjusting the motor includes controlling the motor to rotate counterclockwise or reduce the rotating speed.

[0028] The beneficial effects of the above further technical scheme are as follows: the rotating speed of the motor needs to be quickly adjusted for speed connection during the stepless speed change, at this time, the motor needs to be quickly reversed or reduced in speed according to the specific situation, and the stepless speed change can be continuously realized after the adjustment.

[0029] Advantages of the additional aspects of the application will become apparent in the following description, which is given by way of example only, from the description and from the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 Structure diagram of the continuously variable transmission provided by the embodiment of the application.

[0031] Figure 2 Structure diagram of the continuously variable transmission provided by the embodiment of the application.

[0032] Figure 3 Structure diagram of the continuously variable transmission provided by the embodiment of the application.

[0033] BRIEF DESCRIPTION OF DRAWINGS 1. engine; 2. first gear; 3. reverse clutch; 4. second gear; 5. third gear; 6. forward 1 clutch; 7. forward 2 clutch; 8. sixth gear; 9. auxiliary output shaft; 10. third idler; 11. seventh gear; 12. transmission input shaft; 13. power output mechanism; 14. first idler; 15. generator; 16. second idler; 17. third shaft; 18. power conversion device; 20. vehicle electrical components; 21. power battery; 23. electric motor; 24. first shaft; 25. second shaft; 26. fourth gear; 27. fifth gear; 28. seventh gear; 29. primary planetary set sun gear; 30. first ring gear; 31. planet gears; 33. second ring gear; 34. clutch; 35. transmission housing; 36. carrier; 37. rear axle; 38. first double planetary gears; 39. second double planetary gears; 40. secondary planetary set sun gear; 41. forward clutch. DETAILED DESCRIPTION

[0034] The principles and features of the present application are described below in connection with the drawings, in which the examples are used only to explain the present application and are not intended to limit the scope of the present application.

[0035] As Figure 1As shown, the embodiment of the present application provides a continuously variable transmission, comprising: an engine 1, a first gear 2, a reverse clutch 3, a second gear 4, a third gear 5, a forward clutch 41, a transmission input shaft 12, a first idler 14, a generator 15, a second idler 16, an electric motor 23, a first shaft 24, a second shaft 25, a fourth gear 26, a fifth gear 27, a primary planetary set sun gear 29, a first ring gear 30, a planet gear 31, a second ring gear 33, a clutch 34, a transmission housing 35, a carrier 36, a first double planetary gear 38, a second double planetary gear 39, a secondary planetary set sun gear 40, one end of the transmission input shaft 12 is connected with the engine 1, the first gear 2, the reverse clutch 3 and the forward clutch 41 are all mounted on the transmission input shaft 12, the second gear 4 is connected with the reverse clutch 3, the third gear 5 is connected with the forward clutch 41, the generator 15 is connected with the first gear 2 through the first idler 14, the electric motor 23 is connected with the generator 15, one end of the first shaft 24 is connected with the electric motor 23, the primary planetary set sun gear 29 and the secondary planetary set sun gear 40 are both mounted on the first shaft 24, the second shaft 25 is sleeved outside the first shaft 24, the fourth gear 26, the fifth gear 27 and the first ring gear 30 are all mounted on the second shaft 25, the fourth gear 26 is connected with the second gear 4 through the second idler 16, the fifth gear 27 is engaged with the third gear 5, the planet gear 31, the first double planetary gear 38 and the second double planetary gear 39 are all mounted on the carrier 36, one end of the second ring gear 33 is engaged with the first double planetary gear 38, one end of the clutch 34 is connected with the transmission housing 35, the other end of the second ring gear 33 is connected with the other end of the clutch 34.

[0036] The present application has the advantages that: by designing the tractor mechanical and electrical power continuously variable transmission device, the problems of tractor continuously variable transmission and low transmission efficiency, complex maintenance, high oil requirement and high use cost of the existing CVT transmission housing hydraulic transmission mechanism are solved. The use of the electric motor drive has the advantages of high reliability, high efficiency and reduced energy consumption.

[0037] The planet gear 31 is engaged with the primary planetary set sun gear 29, the second double planetary gear 39 is engaged with the secondary planetary set sun gear 40, and the first double planetary gear 38 is engaged with the second double planetary gear 39. The continuously variable transmission of the embodiment of the present application can be an EMCVT (electromotor mechanical continuous variable transmission) continuously variable transmission.

[0038] Further, the forward gear clutch 41 comprises a forward 1 gear clutch 6 and a forward 2 gear clutch 7, the third gear 5 is connected with the forward 1 gear clutch 6, the forward 2 gear clutch 7 is connected with a sixth gear 8, a seventh gear 28 is arranged on the second shaft 25, and the seventh gear 28 is engaged with the sixth gear 8.

[0039] The beneficial effect of the above further technical solution is that the forward 1 gear clutch and the forward 2 gear clutch are arranged, which facilitates the combination or separation of the corresponding clutch according to actual needs, and improves the stability and reliability.

[0040] As shown in Figure 3 As an alternative to the above-mentioned forward gear clutch 41 comprising the forward 1 gear clutch 6 and the forward 2 gear clutch 7 technical solution, Figure 3 The difference between the structure shown in Figure 1 The difference between the structure shown in

[0041] Further, the transmission input shaft 12 is provided with a seventh gear 11, the seventh gear 11 is connected with a third idler wheel 10, and the third idler wheel 10 is connected with an auxiliary output shaft 9 for driving a hydraulic pump.

[0042] The beneficial effect of the above further technical solution is that the auxiliary output shaft is arranged to drive the hydraulic pump, which reasonably utilizes the power and makes the function of the continuously variable transmission diverse.

[0043] Further, the other end of the transmission input shaft 12 is connected with a power output mechanism 13.

[0044] The beneficial effect of the above further technical solution is that the power output mechanism is arranged to facilitate power transmission and application.

[0045] Further, the second idler wheel 16 is connected with a third shaft 17.

[0046] The beneficial effect of the above further technical solution is that the third shaft is arranged to facilitate the installation and maintenance of the second idler wheel.

[0047] Further, the generator 15 is connected with a power battery 21, the power battery 21 is connected with a power supply conversion device 18, and the power supply conversion device 18 is connected with a whole vehicle electrical component 20.

[0048] The beneficial effect of the further technical scheme is that when the vehicle is running, the electric quantity generated by the generator is partly transmitted to the motor and the other part is stored in the power battery.

[0049] Further, the planet carrier 36 is connected with the rear axle 37.

[0050] The beneficial effect of the further technical scheme is that the rear axle is convenient for power transmission and application.

[0051] The stepless gearbox provided by the embodiment of the application can be a tractor mechanical and electrical power confluence speed change device, comprising: an engine 1 connected with a gearbox input shaft 12, the gearbox input shaft 12 being provided with a first gear 2, a reverse gear clutch 3, a forward 1 gear clutch 6, a forward 2 gear clutch 7, a seventh gear 11 and a power output mechanism 13; wherein the driving parts of the reverse gear clutch 3, the forward 1 gear clutch 6 and the forward 2 gear clutch 7 are all mounted on the gearbox input shaft 12, the driven part of the reverse gear clutch 3 is rigidly mounted with a second gear 4, the driven part of the forward 1 gear clutch 6 is rigidly mounted with a third gear 5, and the driven part of the forward 2 gear clutch 7 is rigidly mounted with a sixth gear 8.

[0052] The first idler wheel 14 is installed on the input shaft of the generator 15 and is engaged with the first gear 2. The generator 15 is electrically connected with the motor 23 and the power battery 21, the power battery 21 is electrically connected with the power conversion device 18, the power conversion device 18 is electrically connected with the low-voltage components 20 of the whole vehicle. The third idler wheel 10 is installed on the auxiliary output shaft 9 and is engaged with the seventh gear 11, and the auxiliary output shaft 9 can be used to drive the hydraulic pump and the like. The output shaft of the motor 23 is rigidly connected with the first shaft 24, and the sun gear 29 of the first planetary gear set and the sun gear 40 of the second planetary gear set are installed on the first shaft 24. The second shaft 25 is sleeved on the first shaft 24, and the fourth gear 26, the fifth gear 27, the seventh gear 28, the first ring gear 30 and the second idler wheel 16 are installed on the second shaft 25. The third shaft 17 is sleeved on the second shaft 25 and is engaged with the second gear 4 and the fourth gear 26. The planetary gear 31, the first ring gear 30 and the sun gear 29 of the first planetary gear set together form the first planetary gear set, the second ring gear 33, the sun gear 40 of the second planetary gear set, the first double planetary gear 38 and the second double planetary gear 39 together form the second planetary gear set, and the first planetary gear set and the second planetary gear set share the carrier 36, which is connected with the planetary gear 31 of the first planetary gear set and the first double planetary gear 38 and the second double planetary gear 39 of the second planetary gear set. The second ring gear 33 is engaged with the gear of the first double planetary gear 38, and the other end is rigidly connected with the driving end of the clutch 34. The clutch 34 has a driving end and a driven end, wherein the driven end is rigidly connected with the transmission case 35, and the driving end is connected with the second ring gear 33. The clutch 34 controls the rigid connection and separation between the second ring gear 33 and the transmission case 35. The purposes of pure electric stage, mechanical-electric power hybrid stage, oil saving, easy maintenance and stepless speed change in the interval are achieved.

[0053] In addition, the application also provides a tractor comprising the stepless transmission of any one of the above.

[0054] In addition, the application also provides a stepless speed change method based on the stepless transmission of any one of the above, which comprises the following steps:

[0055] Starting the engine to rotate the input shaft of the transmission by the engine;

[0056] In the first stage of the forward gear: controlling the motor to rotate counterclockwise, combining the clutch, separating the reverse gear clutch, the forward 1 gear clutch and the forward 2 gear clutch, so that the carrier rotates clockwise, and realizing stepless speed change by controlling the rotating speed of the motor;

[0057] In the second stage of the forward gear: combining the forward 1 gear clutch, separating the reverse gear clutch, the forward 2 gear clutch and the clutch, controlling the motor to rotate clockwise until the rotating speed is 0, and realizing stepless speed change;

[0058] In the third stage of forward gear: separate the forward 1 clutch, the reverse clutch and the clutch, combine the forward 2 clutch, adjust the motor, and realize stepless speed change;

[0059] In the first stage of reverse gear: control the motor to rotate clockwise, combine the clutch, separate the reverse clutch, the forward 1 clutch and the forward 2 clutch, so that the planet carrier rotates counterclockwise, and realize stepless speed change by controlling the rotating speed of the motor;

[0060] In the second stage of reverse gear: combine the reverse clutch, separate the forward 1 clutch, the forward 2 clutch and the clutch, control the motor to reduce the rotating speed until the rotating speed is 0, control the motor to rotate counterclockwise, and realize stepless speed change.

[0061] The beneficial effects of the technical scheme of the present application are that by designing the tractor mechanical and electrical power stepless speed change device, the problems of stepless speed change of the tractor and low transmission efficiency, complex maintenance, high oil requirement and high use cost of the existing CVT transmission hydraulic speed change mechanism are solved. The use of the motor drive has the advantages of high reliability, high efficiency and reduced energy consumption. The pure electric stage and the mechanical and electrical power hybrid stage are realized, and the purposes of saving oil, easy maintenance and stepless speed change in the interval are achieved.

[0062] Further, in the third stage of forward gear, adjusting the motor includes controlling the motor to rotate counterclockwise or reduce the rotating speed.

[0063] The beneficial effects of the above further technical scheme are that the motor rotating speed needs to be quickly adjusted for speed connection during stepless speed change, at this time the motor needs to be quickly reversed or quickly reduced in speed according to specific conditions, and stepless speed change can be continued after adjustment.

[0064] When the vehicle is running, the electric quantity generated by the generator 15 is partly transmitted to the motor 23 and the other part is stored in the power battery 21. The low-voltage power supply of the whole vehicle is converted from high voltage to low voltage by the power conversion device 18 to supply power to the low-voltage components (i.e. the vehicle electrical components 20) of the whole vehicle. The low-voltage generator of the whole vehicle can be omitted to reduce the use cost.

[0065] As shown in FIG. 1, Figure 2 As shown in FIG. 1, Figure 2 The relationship diagram of the transmission system vehicle speed change and the motor and the clutch is shown in FIG. 1, the horizontal coordinate is the vehicle speed, and the vertical coordinate is the motor rotating speed, Figure 2 The A position in FIG. 1 is the combination point of the reverse clutch 3, the B position is the combination point of the forward 1 clutch 6, and the C position is the combination point of the forward 2 clutch 7.

[0066] The first stage, forward gear, pure electric stage, assuming that the engine starts to drive the gearbox input shaft 12 clockwise rotation, the carrier and the rear axle through the shaft, assuming that the carrier and the rear axle shaft clockwise rotation is forward for the vehicle, assuming that the gear counterclockwise rotation is negative, clockwise is positive. Control motor 23 counterclockwise rotation, clutch 34 combination, reverse clutch 3 separation, forward 1 clutch 6 separation, forward 2 clutch 7 separation, the first planetary set this time follow, at this time due to the second planetary set using the first double planetary gear 38 and the second double planetary gear 39, and clutch 34 combination, the second ring gear 33 fixed speed is zero, then the carrier 36 clockwise rotation, at this time according to the double planetary gear planetary set characteristic equation n 太 -kn 齿 =(1+k)n 行 , by controlling the motor speed increase or decrease can realize stepless speed change.

[0067] The second stage, forward gear, mixed stage, when the motor reaches the high efficiency point or the motor transmission efficiency decreases or the motor reaches the maximum speed, at this time the forward 1 clutch 6 is combined, the reverse clutch 3 is separated, the forward 2 clutch 7 is separated, and the clutch 34 is separated. At this time the second planetary set is in the follow state and does not output torque. Since the first planetary set is a single stage planetary set, the first ring gear 30 has a negative speed at this time, and the motor connected single planetary set sun gear 29 has a positive speed. According to the planetary gear set characteristic equation: n 太 +kn 齿 =(1+k)n 行 , wherein: n 太 is the sun gear speed; n 齿 is the ring gear speed; n 行 is the carrier speed; k is the planetary gear set characteristic parameter, k = z 齿 / z 太 , that is, K is the number of teeth of the ring gear divided by the number of teeth of the sun gear. At this time, gradually reduce the motor speed to 0, and then increase the motor speed clockwise to realize stepless speed change. Note: When switching from the first stage to the second stage, the speed connection should be calculated according to the planetary gear set characteristic equation to ensure that the carrier speed does not jump. The specific calculation is as follows: assuming that the planetary gear tooth number is Z 行 , the first planetary set sun gear 29 and the second planetary set sun gear 40 have Z 29 and Z 40 teeth respectively, the third gear 5 and the fifth gear 27 have Z5 and Z 27 teeth respectively, the engine speed is n 发 , and the motor speed is n 电 . Since the carrier speed does not change when switching from the first stage to the second stage, the first stage carrier speed is n 行 =n 电n / (1+k1), just switched to the second stage due to the separation of clutch 34, the second planetary row follows, according to the first planetary row planetary gear set characteristic equation: n 太 +kn 齿 =(1+k)n 行 , calculated n 行 =(n 电 -k·n 发 ·Z5 / Z 27 ) / (1+k2), to ensure the planetary carrier speed is constant, that is, n 电 / (1+k1)=(n 电 -k2·n 发 ·Z5 / Z 27 ) / (1+k2), n 发 =n 电 ·[(1+k)·Z 40 / Z 行 -1] / k·Z5 / Z 27 , where k=Z 30 / Z 40 in the first planetary row, finally obtained by switching from the first stage to the second stage to meet: n 发 =n 电 ·[(1+Z 30 / Z 40 )·Z 40 / Z 行 -1] / Z 30 / Z 40 ·Z5 / Z 27 .

[0068] The third stage, when the motor speed changes from negative to positive, and the vehicle speed reaches a certain value, in order to ensure economy, at this time the forward 1 clutch 6 is disconnected, the reverse clutch 3 is separated, the forward 2 clutch 7 is combined, and the clutch 34 is separated. At this time, the second planetary row is in a follow-up state and does not output torque. At this time, due to the larger sixth gear 8 than the third gear 5, the gear ring speed increases, according to the planetary gear set characteristic equation: n 太 +kn 齿 =(1+k)n 行 , where: n 太 is the sun gear speed; n 齿 is the gear ring speed; n 行 is the planetary carrier speed; k is the planetary gear set characteristic parameter. In order to realize stepless speed change, the motor speed needs to be quickly adjusted for speed connection, at this time the motor may need to be quickly reversed or quickly reduced in speed according to the specific situation. After adjustment, stepless speed change can continue to be realized.

[0069] The first stage in the reverse gear, the control motor rotates clockwise, the clutch 34 is engaged, the reverse gear clutch 3 is separated, the forward 1 gear clutch 6 is separated, the forward 2 gear clutch 7 is separated, the first planetary gear set is driven at this time, at this time, due to the reverse action of the first double planetary gear 38 and the second double planetary gear 39 of the second planetary gear set, the planet carrier 36 rotates counterclockwise, and the speed of the control motor can be increased or decreased to realize the stepless speed change of the reverse gear.

[0070] The second stage in the reverse gear, the hybrid stage, when the motor reaches the point of maximum efficiency or the transmission efficiency decreases or reaches the maximum speed, at this time, the reverse gear clutch 3 is engaged, the forward 1 gear clutch 6 is separated, the forward 2 gear clutch 7 is separated, and the clutch 34 is separated. At this time, the second planetary gear set is in a driven state and does not output torque. Since the first planetary gear set is a single-stage planetary gear set, the first ring gear 30 has a negative speed at this time, and the motor-connected single-stage planetary gear set sun gear 29 has a positive speed. According to the characteristic equation of the planetary gear set: n 太 +kn 齿 =(1+k)n 行 , where: n 太 is the sun gear speed; n 齿 is the ring gear speed; n 行 is the planet carrier speed; k is the characteristic parameter of the planetary gear set. At this time, gradually reduce the motor speed to 0, then increase the motor speed counterclockwise, which can realize stepless speed change. Note: When switching from the first stage to the second stage, the speed connection should be calculated according to the characteristic equation of the planetary gear set to ensure that the planet carrier speed does not jump.

[0071] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A continuously variable transmission (CVT), characterized in that, include: Engine (1), First Gear (2), Reverse Clutch (3), Second Gear (4), Third Gear (5), Forward Gear Clutch, Transmission Input Shaft (12), First Inertia Gear (14), Generator (15), Second Inertia Gear (16), Electric Motor (23), First Shaft (24), Second Shaft (25), Fourth Gear (26), Fifth Gear (27), First-Stage Planetary Set Sun Gear (29), First Ring Gear (30), Planet Gears (31), Second Ring Gear (33), Clutch (34), Transmission Housing (35), Planet Carrier (36), First Double Planetary Gear (38), Second Double Planetary Gear (39) Planetary gears (39), a sun gear (40) of the second-stage planetary gear set, one end of the gearbox input shaft (12) is connected to the engine (1), the first gear (2), the reverse clutch (3) and the forward clutch are all mounted on the gearbox input shaft (12), the second gear (4) is connected to the reverse clutch (3), the third gear (5) is connected to the forward clutch, the generator (15) is connected to the first gear (2) through the first idler gear (14), the electric motor (23) is connected to the generator (15), and the first shaft (24) One end is connected to the motor (23). The sun gear (29) of the first-stage planetary gear set and the sun gear (40) of the second-stage planetary gear set are both mounted on the first shaft (24). The second shaft (25) is sleeved on the outside of the first shaft (24). The fourth gear (26), the fifth gear (27), and the first gear ring (30) are all mounted on the second shaft (25). The fourth gear (26) is connected to the second gear (4) through the second inertial gear (16). The fifth gear (27) meshes with the third gear (5). The planetary gear (31), the first... A pair of planetary gears (38) and a second pair of planetary gears (39) are both mounted on the planet carrier (36). One end of the second ring gear (33) meshes with the first pair of planetary gears (38). One end of the clutch (34) is connected to the gearbox housing (35), and the other end of the second ring gear (33) is connected to the other end of the clutch (34). The sun gear (29) of the first-stage planetary gear set is connected to the first ring gear (30) through planetary gears (31), and the sun gear (40) of the second-stage planetary gear set is connected to the second ring gear (33) through the first pair of planetary gears (38) and the second pair of planetary gears (39).

2. A continuously variable transmission (CVT) according to claim 1, characterized in that, The forward gear clutch includes a forward 1st gear clutch (6) and a forward 2nd gear clutch (7). The third gear (5) is connected to the forward 1st gear clutch (6). The forward 2nd gear clutch (7) is connected to a sixth gear (8). A seventh gear (28) is provided on the second shaft (25). The seventh gear (28) meshes with the sixth gear (8).

3. A continuously variable transmission (CVT) according to claim 1, characterized in that, The gearbox input shaft (12) is provided with a seventh gear (11), the seventh gear (11) is connected to a third idler wheel (10), and the third idler wheel (10) is connected to an auxiliary output shaft (9) for driving a hydraulic pump.

4. A continuously variable transmission (CVT) according to claim 1, characterized in that, The other end of the gearbox input shaft (12) is connected to a power output mechanism (13).

5. A continuously variable transmission (CVT) according to claim 1, characterized in that, The second inertial wheel (16) is connected to the third shaft (17).

6. A continuously variable transmission (CVT) according to claim 1, characterized in that, The generator (15) is connected to a power battery (21), the power battery (21) is connected to a power conversion device (18), and the power conversion device (18) is connected to the vehicle electrical components (20).

7. A continuously variable transmission (CVT) according to claim 1, characterized in that, The planetary carrier (36) is connected to the rear axle (37).

8. A tractor, characterized in that, The continuously variable transmission includes any one of claims 1 to 7.

9. A continuously variable transmission method, characterized in that, Based on any one of claims 1 to 7, the continuously variable transmission method includes: Start the engine, which will drive the gearbox input shaft to rotate. In the first stage of forward gear: control the motor to rotate counterclockwise, engage the clutch, disengage the reverse gear clutch, forward 1st gear clutch and forward 2nd gear clutch, so that the planetary carrier rotates clockwise, and continuously variable transmission is achieved by controlling the speed of the motor; In the second stage of forward gear: engage the forward 1st gear clutch, disengage the reverse gear clutch, forward 2nd gear clutch and clutch, control the motor to decelerate until the speed is 0, control the motor to rotate clockwise to achieve stepless speed change; In the third stage of forward gear: disengage the forward 1st gear clutch, reverse gear clutch and clutch, engage the forward 2nd gear clutch, adjust the motor to achieve continuously variable transmission; In the first stage of reverse gear: the control motor rotates clockwise, engages the clutch, disengages the reverse gear clutch, the first forward gear clutch, and the second forward gear clutch, causing the planetary carrier to rotate counterclockwise, and continuously variable transmission is achieved by controlling the speed of the motor; In the second stage of reverse gear: engage the reverse gear clutch, disengage the forward 1st gear clutch, forward 2nd gear clutch and clutch, control the motor to decelerate until the speed is 0, control the motor to rotate counterclockwise to achieve stepless speed change.

10. A continuously variable transmission method according to claim 9, characterized in that, In the third stage of forward gear, adjusting the motor includes controlling the motor to rotate counterclockwise or decelerate.

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