Coaxial output double-flow transmission continuously variable transmission and speed change method

Abstract

The invention discloses a coaxial output double-flow transmission continuously variable transmission which comprises a planetary gear transmission mechanism and a hydraulic transmission mechanism. The input end of the planetary gear transmission mechanism is coaxially and fixedly connected with the input shaft, the first output end of the planetary gear transmission mechanism is coaxially and fixedly connected with the third gear, the second output end of the planetary gear transmission mechanism is connected with the input end of the hydraulic transmission mechanism through the gear mechanism, and the output end of the hydraulic transmission mechanism is connected with the fourth gear. The third gear and the fourth gear are in meshed connection; and the third gear is coaxially and fixedly connected with the main output gear. The invention further discloses a coaxial output double-flow transmission stepless speed change method. The coaxial output double-flow transmission continuously variable transmission is not provided with a clutch / brake, so that the failure rate is low; and the gear transmission structure is simpler, so that the whole mechanical structure is simple, and the manufacturing cost is low.

Description

Technical Field

[0001] The invention belongs to the technical field of transmissions, and in particular relates to a coaxial output dual-flow transmission continuously variable transmission and a speed changing method. Background Art

[0002] As the core component of the transmission system, the gearbox has the function of speed regulation, so that the vehicle or other industrial equipment can adapt to the speed requirements under different working conditions. It is widely used in vehicles and industrial fields. Among them, the continuously variable transmission solves the problem of manual shifting and power shifting transmission when shifting, and the speed regulation is smoother, so it has been widely promoted and applied. The existing continuously variable transmission mostly adopts the structural form of a combination of hydrostatic and power shift boxes to form a segmented continuously variable transmission.

[0003] However, the existing step-type continuously variable transmission has a complex structure and usually needs to be combined with a clutch / brake unit, so it is very easy to cause problems due to clutch / brake failure.

[0004] Based on this, the present application proposes a coaxial output dual-flow transmission continuously variable transmission and a speed changing method. The transmission eliminates the clutch / brake unit in the power shifting, avoids the failure caused by the power shifting clutch / brake, has the advantages of a wide speed regulation range, stepless speed regulation within the full speed range, and high transmission efficiency. The overall mechanical structure is simple and the manufacturing cost is low. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art and to provide a coaxial output dual-flow transmission continuously variable transmission and a speed changing method.

[0006] To achieve the above object, the present invention adopts the following technical solution:

[0007] A coaxial output dual-flow transmission continuously variable transmission, comprising a planetary gear transmission mechanism and a hydraulic transmission mechanism;

[0008] The input end of the planetary gear transmission mechanism is coaxially fixedly connected to the input shaft, the first output end of the planetary gear transmission mechanism is coaxially fixedly connected to the third gear, the second output end of the planetary gear transmission mechanism is connected to the input end of the hydraulic transmission mechanism through a gear mechanism, the output end of the hydraulic transmission mechanism is connected to the fourth gear, and the third gear and the fourth gear are meshed and connected;

[0009] The third gear is coaxially fixedly connected to the main output gear.

[0010] Preferably, the planetary gear transmission mechanism comprises a planet carrier, a planetary gear, a sun gear, and an inner gear ring;

[0011] The planet carrier is coaxially fixedly connected to the input shaft, a plurality of planetary gears are evenly arranged on the planet carrier along the circumferential direction and rotate with the planet carrier, the inner gear ring surrounds all the planetary gears and meshes with all the planetary gears, and the sun gear is located in the middle and meshes with all the planetary gears;

[0012] The sun gear is coaxially fixedly connected to the third gear;

[0013] The inner gear ring is connected to the input end of the hydraulic transmission mechanism through a gear mechanism.

[0014] Preferably, the hydraulic transmission mechanism includes a variable displacement pump and a variable displacement motor; the gear mechanism includes a first gear and a second gear;

[0015] The inner gear ring is coaxially fixedly connected to the first gear, the first gear and the second gear are meshingly connected, the second gear is coaxially fixedly connected to the input end of the variable pump, the output end of the variable pump is connected to the input end of the variable motor, and the output end of the variable motor is coaxially fixedly connected to the fourth gear.

[0016] Preferably, a first connecting shaft is coaxially fixedly arranged in the middle of the sun gear, the third gear and the main output gear, and a through first central shaft hole is arranged in the middle of the first connecting shaft;

[0017] A power take-off output shaft passing through the first central axis hole is fixedly arranged on one end of the planet carrier facing away from the input shaft;

[0018] The input shaft and the power take-off output shaft are coaxially arranged.

[0019] Preferably, a second connecting shaft is coaxially fixedly arranged in the middle of the inner gear ring and the first gear, and a through second central shaft hole is arranged in the middle of the second connecting shaft;

[0020] The input shaft passes through the second central shaft hole.

[0021] Preferably, the variable displacement pump is a bidirectional variable displacement pump.

[0022] Preferably, a high-low gear switching mechanism is arranged on the first connecting shaft between the third gear and the main output gear, the output end of the high-low gear switching mechanism is coaxially fixedly connected with the main output gear, the high gear input end of the high-low gear switching mechanism is coaxially fixedly connected with the third gear, the low gear input end of the high-low gear switching mechanism is coaxially fixedly connected with the fifth gear, and the fifth gear coaxial sleeve is outside the first connecting shaft;

[0023] The fifth gear is meshed with the sixth gear, and the sixth gear is coaxially fixedly connected with the fourth gear.

[0024] The invention also discloses a coaxial output double-flow transmission stepless speed change method.

[0025] A coaxial output dual-flow transmission continuously variable speed method is implemented based on a coaxial output dual-flow transmission continuously variable transmission, and the speed change method is:

[0026] The power input is transmitted to the planet carrier through the input shaft, and then divided into two power outputs. The first power output is transmitted to the third gear through the sun gear, and the second power output is transmitted to the fourth gear through the inner ring gear, the first gear, the second gear, the variable pump, and the variable motor. The two power outputs are meshed and merged with the third gear and the fourth gear and then output through the main output gear;

[0027] In the above operation process, the speed change method includes:

[0028] Adjust the displacement of the variable pump to increase, keep the displacement of the variable motor unchanged, and the output speed of the main output gear will increase; adjust the displacement of the variable pump to decrease, keep the displacement of the variable motor unchanged, and the output speed of the main output gear will slow down;

[0029] Keep the displacement of the variable pump unchanged, adjust the displacement of the variable motor to increase, and the output speed of the main output gear will slow down; keep the displacement of the variable pump unchanged, adjust the displacement of the variable motor to decrease, and the output speed of the main output gear will speed up;

[0030] The displacement of the variable pump increases, the displacement of the variable motor decreases, and the output speed of the main output gear becomes faster;

[0031] The displacement of the variable pump decreases, the displacement of the variable motor increases, and the output speed of the main output gear slows down.

[0032] The invention also discloses a coaxial output double-flow transmission stepless speed change method.

[0033] A coaxial output dual-flow transmission continuously variable speed method is implemented based on a coaxial output dual-flow transmission continuously variable transmission, and the speed change method is:

[0034] The power input is transmitted to the planet carrier through the input shaft, and then divided into two power outputs. The first power output is transmitted to the third gear through the sun gear, and the second power output is transmitted to the fourth gear through the inner ring gear, the first gear, the second gear, the variable pump, and the variable motor. When the high-low gear switching structure is adjusted to the high gear, the two power outputs are output through the main output gear after the third gear and the fourth gear are meshed and converged in the high gear. When the high-low gear switching structure is adjusted to the low gear, the two power outputs are output through the main output gear after the third gear and the fourth gear are meshed and converged and the sixth gear and the fifth gear are meshed in the low gear.

[0035] In the above operation process, the speed change method includes:

[0036] Adjust the displacement of the variable pump to increase, keep the displacement of the variable motor unchanged, and the output speed of the main output gear will increase; adjust the displacement of the variable pump to decrease, keep the displacement of the variable motor unchanged, and the output speed of the main output gear will slow down;

[0037] Keep the displacement of the variable pump unchanged, adjust the displacement of the variable motor to increase, and the output speed of the main output gear will slow down; keep the displacement of the variable pump unchanged, adjust the displacement of the variable motor to decrease, and the output speed of the main output gear will speed up;

[0038] The displacement of the variable pump increases, the displacement of the variable motor decreases, and the output speed of the main output gear becomes faster;

[0039] The displacement of the variable pump decreases, the displacement of the variable motor increases, and the output speed of the main output gear slows down.

[0040] The beneficial effects of the present invention are:

[0041] (1) The coaxial output dual-flow transmission continuously variable transmission of the present invention has no clutch / brake and has a low failure rate; and the gear transmission structure is simpler, thereby making the overall mechanical structure simple and the manufacturing cost low;

[0042] (2) In the present invention, except for the variable displacement pump, the second gear, the variable displacement motor, and the fourth gear, the remaining gears and the transmission shaft are coaxially arranged with the planetary gear, which is compact in space and small in size;

[0043] (3) The coaxial output dual-flow transmission continuously variable transmission of the present invention can continuously and steplessly adjust the speed from zero to the maximum value, whether in low-speed working conditions or high-speed transportation conditions, and has the advantages of wide speed regulation range, stepless speed regulation within the full speed range, and high transmission efficiency;

[0044] (4) The variable pump in the present invention is a bidirectional transmission pump, and the swash plate of the variable pump can realize bidirectional swing. When the swash plate changes the swing direction, the oil inlet and outlet of the variable pump change, and the oil inlet and outlet of the variable motor change accordingly, and the rotation direction of the output shaft of the variable motor changes, so that the vehicle can move forward or reverse. The forward and reverse switching is simple, and there is no stuck phenomenon in the high and low gear switching mechanism;

[0045] (5) In the present invention, at low speed, power is mainly transmitted from the hydraulic transmission path. As the speed increases, the power flow transmitted by the hydraulic transmission path gradually decreases, and the power flow transmitted by the mechanical transmission path gradually increases. Therefore, the present invention has the advantages of both high torque of hydraulic transmission and high efficiency of mechanical transmission.

[0046] (6) The high- and low-speed switching mechanism meets the requirements of low-speed, high-torque operating conditions and high-speed transportation conditions, and there will be no jamming when shifting gears. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The drawings in the specification, which constitute a part of the present application, are used to provide further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute improper limitations on the present application.

[0048] Figure 1 1 is a schematic structural diagram of a coaxial output dual-flow transmission continuously variable transmission in Embodiment 1 of the present invention;

[0049] Figure 2 is a schematic structural diagram of a coaxial output dual-flow transmission continuously variable transmission in embodiment 2 of the present invention;

[0050] Figure 3 is a power transmission circuit diagram in Embodiment 3 of the present invention;

[0051] Figure 4 This is a power transmission circuit diagram of the high gear in the fourth embodiment of the present invention;

[0052] Figure 5 This is a power transmission circuit diagram of the low gear position in the fourth embodiment of the present invention;

[0053] in:

[0054] 11-sun gear, 12-planet gear, 13-ring gear, 141-input shaft, 142-planet carrier, 143-power take-off output shaft;

[0055] 21- first gear, 22- second gear;

[0056] 31- variable pump, 32- variable motor;

[0057] 41- third gear, 42- fourth gear;

[0058] 5- Main output gear;

[0059] 6-first connecting shaft, 61-first central shaft hole;

[0060] 7-second connecting shaft, 71-second central shaft hole;

[0061] 81-fifth gear, 82-sixth gear;

[0062] 9-High and low gear switching mechanism;

[0063] Power input flow direction;

[0064] The first power output flow direction;

[0065] The second power output flow direction;

[0066] Flow direction after confluence;

[0067] Flow direction after high-level confluence;

[0068] Flow direction after low-speed confluence. DETAILED DESCRIPTION

[0069] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0070] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0071] In the present invention, the directions or positional relationships indicated by terms such as "upper", "lower", "bottom", "top", etc. are based on the directions or positional relationships shown in the accompanying drawings. They are relational words determined only for the convenience of describing the structural relationships of the various parts or elements of the present invention. They do not specifically refer to any part or element in the present invention and cannot be understood as limitations on the present invention.

[0072] In the present invention, terms such as "connected" and "connection" should be understood in a broad sense, indicating that the connection can be fixed, integral or detachable; it can be directly connected or indirectly connected through an intermediate medium. Relevant scientific research or technical personnel in this field can determine the specific meaning of the above terms in the present invention according to specific circumstances, and they should not be understood as limiting the present invention.

[0073] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0074] Embodiment 1:

[0075] like Figure 1 As shown, a coaxial output dual-flow transmission continuously variable transmission includes a planetary gear transmission mechanism and a hydraulic transmission mechanism;

[0076] The input end of the planetary gear transmission mechanism is coaxially fixedly connected to the input shaft 141, the first output end of the planetary gear transmission mechanism is coaxially fixedly connected to the third gear 41, the second output end of the planetary gear transmission mechanism is connected to the input end of the hydraulic transmission mechanism through a gear mechanism, the output end of the hydraulic transmission mechanism is connected to the fourth gear 42, and the third gear 41 and the fourth gear 42 are meshedly connected;

[0077] The third gear 41 is coaxially fixedly connected to the main output gear 5 .

[0078] Preferably, the planetary gear transmission mechanism includes a planet carrier 142, a planetary gear 12, a sun gear 11, and an inner gear ring 13;

[0079] The planet carrier 142 is coaxially fixedly connected to the input shaft 141, a plurality of planetary gears 12 are evenly arranged on the planet carrier 142 along the circumferential direction and rotate with the planet carrier 142, the inner gear ring 13 surrounds all the planetary gears 12 and meshes with all the planetary gears 12, and the sun gear 11 is located in the middle and meshes with all the planetary gears 12;

[0080] The sun gear 11 is coaxially fixedly connected to the third gear 41, that is, the central axis of the sun gear 11 is the first output end of the planetary gear transmission mechanism;

[0081] The inner gear ring 13 is connected to the input end of the hydraulic transmission mechanism through a gear mechanism, that is, the central axis of the inner gear ring 13 is the second output end of the planetary gear transmission mechanism.

[0082] Preferably, the hydraulic transmission mechanism includes a variable displacement pump 31 and a variable displacement motor 32; the gear mechanism includes a first gear 21 and a second gear 22;

[0083] The inner gear ring 13 is coaxially fixedly connected to the first gear 21, the first gear 21 and the second gear 22 are meshedly connected, the second gear 22 is coaxially fixedly connected to the input end of the variable pump 31, the output end of the variable pump 31 is connected to the input end of the variable motor 32, and the output end of the variable motor 32 is coaxially fixedly connected to the fourth gear 42.

[0084] Preferably, a first connecting shaft 6 is coaxially fixedly disposed in the middle of the sun gear 11, the third gear 41, and the main output gear 5, and a through first central shaft hole 61 is disposed in the middle of the first connecting shaft 6;

[0085] The end of the planet carrier 142 facing away from the input shaft 141 is fixed with a power output shaft 143 passing through the first central axis hole 61;

[0086] The input shaft 141 and the power take-off output shaft 143 are coaxially arranged.

[0087] Preferably, the second connecting shaft 7 is coaxially fixedly arranged in the middle of the inner gear ring 13 and the first gear 21, and a through second central shaft hole 71 is arranged in the middle of the second connecting shaft 7;

[0088] The input shaft 141 passes through the second central shaft hole 71 .

[0089] Preferably, the variable displacement pump 31 is a bidirectional variable displacement pump.

[0090] In Embodiment 1, the input shaft 141, the first gear 21, the planet carrier 142, the internal gear ring 13, the sun gear 11, the third gear 41, the main output gear 5, and the power take-off output shaft 143 are all coaxially arranged, with a compact space and small size.

[0091] Embodiment 2:

[0092] On the basis of Example 1, Figure 2 As shown, a high-low gear switching mechanism 9 is arranged on the first connecting shaft 6 between the third gear 41 and the main output gear 5. The high-low gear switching mechanism 9 is a prior art and can be a spline / gear meshing sleeve type; the output end of the high-low gear switching mechanism 9 is coaxially fixedly connected with the main output gear 5, the high gear input end of the high-low gear switching mechanism 9 is coaxially fixedly connected with the third gear 41, and the low gear input end of the high-low gear switching mechanism 9 is coaxially fixedly connected with the fifth gear 81, and the fifth gear 81 is coaxially sleeved on the outside of the first connecting shaft 6;

[0093] The fifth gear 81 is meshedly connected with the sixth gear 82 , and the sixth gear 82 is coaxially fixedly connected with the fourth gear 42 .

[0094] In Embodiment 2, the input shaft 141, the first gear 21, the planet carrier 142, the internal gear ring 13, the sun gear 11, the third gear 41, the fifth gear 81, the main output gear 5, and the power take-off output shaft 143 are all coaxially arranged, with compact space and small size.

[0095] Embodiment 3:

[0096] A coaxial output dual-flow transmission continuously variable speed method is implemented based on the coaxial output dual-flow transmission continuously variable transmission in embodiment 1, and the speed change method is:

[0097] The power input is transmitted to the planet carrier 142 through the input shaft 141, and then divided into two power outputs. The first power output is transmitted to the third gear 41 through the sun gear 11, and the second power output is transmitted to the fourth gear 42 through the inner ring 13, the first gear 21, the second gear 22, the variable pump 31, and the variable motor 32. The two power outputs are meshed and merged with the third gear 41 and the fourth gear 42 and then output through the main output gear 5; wherein the power transmission in embodiment 3 is as follows Figure 3 As shown;

[0098] In the above operation process, the speed change method includes:

[0099] The displacement of the variable pump 31 is increased, the displacement of the variable motor 32 is kept unchanged, and the output speed of the main output gear 5 becomes faster; the displacement of the variable pump 31 is reduced, the displacement of the variable motor 32 is kept unchanged, and the output speed of the main output gear 5 becomes slower;

[0100] Keep the displacement of the variable pump 31 unchanged, increase the displacement of the variable motor 32, and the output speed of the main output gear 5 slows down; keep the displacement of the variable pump 31 unchanged, reduce the displacement of the variable motor 32, and the output speed of the main output gear 5 speeds up;

[0101] The displacement of the variable pump 31 increases, the displacement of the variable motor 32 decreases, and the output speed of the main output gear 5 becomes faster;

[0102] The displacement of the variable displacement pump 31 decreases, the displacement of the variable displacement motor 32 increases, and the output speed of the main output gear 5 slows down.

[0103] Embodiment 4:

[0104] A coaxial output dual-flow transmission continuously variable speed method is implemented based on the coaxial output dual-flow transmission continuously variable transmission in embodiment 2, and the speed change method is:

[0105] The power input is transmitted to the planetary carrier 142 through the input shaft 141, and then divided into two power outputs. The first power output is transmitted to the third gear 41 through the sun gear 11, and the second power output is transmitted to the fourth gear 42 through the inner ring 13, the first gear 21, the second gear 22, the variable pump 31, and the variable motor 32. When the high-low gear switching structure 9 is adjusted to a high gear, the two power outputs are output through the main output gear 5 after the third gear 41 and the fourth gear 42 are meshed and converged at the high gear. When the high-low gear switching structure 9 is adjusted to a low gear, the two power outputs are output through the main output gear 5 after the third gear 41 and the fourth gear 42 are meshed and converged after the sixth gear 82 and the fifth gear 81 are meshed at the low gear. The power transmission at the high gear in Example 4 is as follows. Figure 4 As shown, the power transmission in the low gear position in the embodiment 4 is as follows Figure 5 As shown;

[0106] In the above operation process, the speed change method includes:

[0107] The displacement of the variable pump 31 is increased, the displacement of the variable motor 32 is kept unchanged, and the output speed of the main output gear 5 becomes faster; the displacement of the variable pump 31 is reduced, the displacement of the variable motor 32 is kept unchanged, and the output speed of the main output gear 5 becomes slower;

[0108] Keep the displacement of the variable pump 31 unchanged, increase the displacement of the variable motor 32, and the output speed of the main output gear 5 slows down; keep the displacement of the variable pump 31 unchanged, reduce the displacement of the variable motor 32, and the output speed of the main output gear 5 speeds up;

[0109] The displacement of the variable pump 31 increases, the displacement of the variable motor 32 decreases, and the output speed of the main output gear 5 becomes faster;

[0110] The displacement of the variable displacement pump 31 decreases, the displacement of the variable displacement motor 32 increases, and the output speed of the main output gear 5 slows down.

[0111] In the present invention, power is input from the planetary carrier 141 and then output through two diversions. One power path is connected in series with a hydraulic closed system consisting of a variable pump 31 and a variable motor 32. This power path is a hydraulic transmission path, and the other path is gear transmission. This power path is a mechanical transmission path. The diverted hydraulic transmission path and the mechanical transmission path finally converge into a total output path. The relationship between the total output speed and the input speed is related to the number of teeth on the planetary gear. When the hydraulic transmission path is adjusted to change its speed, the speed of the mechanical transmission path changes accordingly, thereby achieving the purpose of stepless speed regulation. In the present application, the variable pump 31 is a bidirectional transmission pump, and the swash plate of the variable pump 31 can achieve bidirectional swing. When the swash plate changes the swing direction, the inlet and outlet of the variable pump 31 changes, and the inlet and outlet of the variable motor 32 changes accordingly. The rotation direction of the output shaft of the variable motor 32 changes, thereby enabling the vehicle to move forward or reverse, and the high and low gear switching mechanism 9 will not have a stuck phenomenon.

[0112] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not a limitation of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the protection scope of the present invention.

Claims

1. A coaxial output dual-flow transmission continuously variable transmission, comprising a planetary gear transmission mechanism and a hydraulic transmission mechanism; characterized in that: The input end of the planetary gear transmission mechanism is coaxially fixedly connected to the input shaft, the first output end of the planetary gear transmission mechanism is coaxially fixedly connected to the third gear, the second output end of the planetary gear transmission mechanism is connected to the input end of the hydraulic transmission mechanism through a gear mechanism, the output end of the hydraulic transmission mechanism is connected to the fourth gear, and the third gear and the fourth gear are meshed and connected; The third gear is coaxially fixedly connected to the main output gear.

2. The coaxial output dual-flow transmission continuously variable transmission as claimed in claim 1, characterized in that: The planetary gear transmission mechanism includes a planet carrier, planetary gears, a sun gear, and an inner gear ring; The planet carrier is coaxially fixedly connected to the input shaft, a plurality of planetary gears are evenly arranged on the planet carrier along the circumferential direction and rotate with the planet carrier, the inner gear ring surrounds all the planetary gears and meshes with all the planetary gears, and the sun gear is located in the middle and meshes with all the planetary gears; The sun gear is coaxially fixedly connected to the third gear; The inner gear ring is connected to the input end of the hydraulic transmission mechanism through a gear mechanism.

3. The coaxial output dual-flow transmission continuously variable transmission as claimed in claim 2, characterized in that: The hydraulic transmission mechanism includes a variable displacement pump and a variable displacement motor; the gear mechanism includes a first gear and a second gear; The inner gear ring is coaxially fixedly connected to the first gear, the first gear and the second gear are meshingly connected, the second gear is coaxially fixedly connected to the input end of the variable pump, the output end of the variable pump is connected to the input end of the variable motor, and the output end of the variable motor is coaxially fixedly connected to the fourth gear.

4. The coaxial output dual-flow transmission continuously variable transmission as claimed in claim 3, characterized in that: A first connecting shaft is coaxially fixedly arranged in the middle of the sun gear, the third gear and the main output gear, and a first central shaft hole is arranged in the middle of the first connecting shaft; A power take-off output shaft passing through the first central axis hole is fixedly arranged on one end of the planet carrier facing away from the input shaft; The input shaft and the power take-off output shaft are coaxially arranged.

5. The coaxial output dual-flow transmission continuously variable transmission as claimed in claim 4, characterized in that: A second connecting shaft is coaxially fixedly arranged in the middle of the inner gear ring and the first gear, and a through second central shaft hole is arranged in the middle of the second connecting shaft; The input shaft passes through the second central shaft hole.

6. The coaxial output dual-flow transmission continuously variable transmission as claimed in claim 5, characterized in that: The variable displacement pump is a bidirectional variable displacement pump.

7. The coaxial output dual-flow transmission continuously variable transmission as claimed in claim 6, characterized in that: A high-low gear switching mechanism is arranged on the first connecting shaft between the third gear and the main output gear, the output end of the high-low gear switching mechanism is coaxially fixedly connected with the main output gear, the high gear input end of the high-low gear switching mechanism is coaxially fixedly connected with the third gear, the low gear input end of the high-low gear switching mechanism is coaxially fixedly connected with the fifth gear, and the fifth gear is coaxially sleeved on the outside of the first connecting shaft; The fifth gear is meshed with the sixth gear, and the sixth gear is coaxially fixedly connected with the fourth gear.

8. A method for continuously variable transmission with coaxial output dual-flow transmission, implemented based on the coaxial output dual-flow transmission continuously variable transmission as claimed in claim 6, characterized in that: The speed change method is: The power input is transmitted to the planet carrier through the input shaft, and then divided into two power outputs. The first power output is transmitted to the third gear through the sun gear, and the second power output is transmitted to the fourth gear through the inner ring gear, the first gear, the second gear, the variable pump, and the variable motor. The two power outputs are meshed and merged with the third gear and the fourth gear and then output through the main output gear; In the above operation process, the speed change method includes: Adjust the displacement of the variable pump to increase, keep the displacement of the variable motor unchanged, and the output speed of the main output gear will increase; adjust the displacement of the variable pump to decrease, keep the displacement of the variable motor unchanged, and the output speed of the main output gear will slow down; Keep the displacement of the variable pump unchanged, adjust the displacement of the variable motor to increase, and the output speed of the main output gear will slow down; keep the displacement of the variable pump unchanged, adjust the displacement of the variable motor to decrease, and the output speed of the main output gear will speed up; The displacement of the variable pump increases, the displacement of the variable motor decreases, and the output speed of the main output gear becomes faster; The displacement of the variable pump decreases, the displacement of the variable motor increases, and the output speed of the main output gear slows down.

9. A method for continuously variable transmission with coaxial output dual-flow transmission, implemented based on the coaxial output dual-flow transmission continuously variable transmission as claimed in claim 7, characterized in that: The speed change method is: The power input is transmitted to the planet carrier through the input shaft, and then divided into two power outputs. The first power output is transmitted to the third gear through the sun gear, and the second power output is transmitted to the fourth gear through the inner ring gear, the first gear, the second gear, the variable pump, and the variable motor. When the high-low gear switching structure is adjusted to the high gear, the two power outputs are output through the main output gear after the third gear and the fourth gear are meshed and converged in the high gear. When the high-low gear switching structure is adjusted to the low gear, the two power outputs are output through the main output gear after the third gear and the fourth gear are meshed and converged and the sixth gear and the fifth gear are meshed in the low gear. In the above operation process, the speed change method includes: Adjust the displacement of the variable pump to increase, keep the displacement of the variable motor unchanged, and the output speed of the main output gear will increase; adjust the displacement of the variable pump to decrease, keep the displacement of the variable motor unchanged, and the output speed of the main output gear will slow down; Keep the displacement of the variable pump unchanged, adjust the displacement of the variable motor to increase, and the output speed of the main output gear will slow down; keep the displacement of the variable pump unchanged, adjust the displacement of the variable motor to decrease, and the output speed of the main output gear will speed up; The displacement of the variable pump increases, the displacement of the variable motor decreases, and the output speed of the main output gear becomes faster; The displacement of the variable pump decreases, the displacement of the variable motor increases, and the output speed of the main output gear slows down.

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