Hydraulic-mechanical compound transmission system and control method of hybrid power tractor

Abstract

The present invention provides a hydraulic-mechanical compound transmission system and control method of a hybrid tractor, comprising an engine, a vehicle controller, a motor, a transmission system, and a second planetary gear mechanism, wherein the transmission system comprises a first planetary gear mechanism, a hydraulic transmission device, and a mechanical transmission device; the first planetary gear mechanism is respectively connected to the hydraulic transmission device and the mechanical transmission device, and the hydraulic transmission device and the mechanical transmission device are respectively connected to a total power output shaft; the total power output shaft is connected to the second planetary gear mechanism; the engine is respectively connected to the first planetary gear mechanism and the mechanical transmission device, and the motor is respectively connected to the first planetary gear mechanism and the mechanical transmission device; the second planetary gear mechanism is respectively connected to the first output shaft and the second output shaft; different transmission ratios between the engine and / or the motor and the first output shaft and / or the second output shaft are provided by the vehicle controller. The present invention can realize mechanical transmission, hydraulic transmission, and mechanical-hydraulic compound transmission.

Description

Technical Field

[0001] The present invention relates to the field of agricultural machinery or tractors, and in particular to a hydraulic-mechanical composite transmission system and a control method of a hybrid power tractor. Background Art

[0002] my country is a large agricultural country. As an agricultural machinery, tractors play a vital role in the development of agriculture in my country. Traditional tractors are powered entirely by engines, which have many gears, complex operation, high pollutant emissions, complex transmission systems and low efficiency. With the rise of hybrid technology, the use of engines and motors as the power of tractors can effectively reduce tractor emissions and fuel consumption, and has become a current research hotspot.

[0003] Hybrid technology was first used in passenger cars and the technology is relatively mature. Existing research on hybrid tractors draws on a lot of experience from passenger cars. The emergence of hybrid tractors has reduced tractor emissions and energy consumption, but tractors need to take into account more complex field operation conditions than passenger cars. In addition, hybrid tractors will experience power interruption when shifting gears in engine drive mode.

[0004] The motor and hydraulic motor can realize mechanical stepless speed regulation and hydraulic stepless speed regulation. In the transmission system, the speed can smoothly transition between the minimum and maximum values ​​without shifting, which greatly improves the driving experience. Hybrid tractors can achieve this function through the drive motor. In a single-motor hybrid system, when the battery power is low, the motor cannot output power, and the power can only be output by the engine, so the continuous stepless speed regulation function cannot be achieved; in a multi-motor hybrid system, when the battery power is low, the engine drives the generator to generate electricity, and part of the electricity can drive the motor to output power to achieve stepless speed regulation. However, the cost and complexity of the multi-motor system will increase, and the power transmission path to achieve stepless speed regulation is long, and the energy loss is large. Summary of the invention

[0005] In view of the deficiencies in the prior art, in order to solve the problems in the prior art such as the complicated working conditions of the tractor, poor driving experience during frequent gear shifting or reversing, power interruption during engine-driven gear shifting, discontinuous stepless speed regulation function of the single-motor hybrid system, and large energy loss when the multi-motor hybrid system realizes the stepless speed regulation function, the present invention provides a hybrid tractor hydraulic-mechanical compound transmission system and a control method thereof, which can realize mechanical transmission, hydraulic transmission, and mechanical-hydraulic compound transmission.

[0006] The present invention achieves the above technical objectives through the following technical means.

[0007] A hydraulic-mechanical compound transmission system of a hybrid tractor comprises an engine, a vehicle controller, a motor, a transmission system, a second planetary gear mechanism, a clutch assembly, a brake assembly and a synchronizer assembly, wherein the transmission system comprises a first planetary gear mechanism, a hydraulic transmission device and a mechanical transmission device; the first planetary gear mechanism is respectively connected to the hydraulic transmission device and the mechanical transmission device, and the hydraulic transmission device and the mechanical transmission device are respectively connected to a total power output shaft; the total power output shaft is connected to the second planetary gear mechanism; the engine is respectively connected to the first planetary gear mechanism and the mechanical transmission device, and the motor is respectively connected to the first planetary gear mechanism and the mechanical transmission device; the second planetary gear mechanism is respectively connected to the first output shaft and the second output shaft; the clutch assembly, the brake assembly and the synchronizer assembly are selectively controlled by the vehicle controller to provide different transmission ratios between the engine and / or the motor and the first output shaft and / or the second output shaft.

[0008] Further, the clutch assembly includes a first clutch CL1, a second clutch CL2, a third clutch CL3, a fifth clutch CL5, a sixth clutch CL6, and a seventh clutch CL7;

[0009] The first clutch CL1 is used to selectively connect the engine output shaft with the planet carrier of the first planetary gear mechanism; the third clutch CL3 is used to selectively connect the sun gear of the first planetary gear mechanism with the input end of the hydraulic transmission device; the fifth clutch CL5 is used to selectively connect the output end of the hydraulic transmission device with the total power output shaft; the sixth clutch CL6 is used to selectively connect the first output shaft with the ring gear of the second planetary gear mechanism; the seventh clutch CL7 is used to selectively connect the first output shaft with the second output shaft;

[0010] The mechanical transmission device includes an engine Ⅰ gear pair, a shift shaft 3, a shift shaft 1, a third planetary gear mechanism, a third transmission gear pair, an engine Ⅱ gear pair, a fourth planetary gear mechanism, a first bevel gear pair, a shift shaft 2 and a second bevel gear pair; the sun gear of the first planetary gear mechanism is connected to the shift shaft 3 through the second bevel gear pair, and the shift shaft 1 is connected to the ring gear of the third planetary gear mechanism; the planet carrier of the third planetary gear mechanism is connected to the sun gear of the fourth planetary gear mechanism through the first bevel gear pair; the planet carrier of the fourth planetary gear mechanism is connected to the total power output shaft, and the shift shaft 2 is connected to the sun gear of the third planetary gear mechanism; the second clutch CL2 is used to selectively connect the motor output shaft to the ring gear of the fourth planetary gear mechanism;

[0011] The synchronizer assembly includes a first synchronizer S1 and a second synchronizer S2. The first synchronizer S1 is used to selectively synchronize the shift shaft with the shift shaft through the engine gear pair of gear Ⅰ; the second synchronizer S2 is used to selectively synchronize the shift shaft with the sun gear of the third planetary gear mechanism through the engine gear pair of gear Ⅱ.

[0012] Furthermore, the clutch assembly also includes a fourth clutch CL4, which is used to selectively connect the motor output shaft to the ring gear of the first planetary gear mechanism; the brake assembly includes brake B1, brake B2, brake B3, brake B4, brake B5, brake B6, brake B7 and brake B8; the brake B1 is used to connect the ring gear of the first planetary gear mechanism to the fixed part; the brake B2 is used to connect the sun gear of the first planetary gear mechanism to the fixed part; the brake B3 is used to connect the ring gear of the second planetary gear mechanism to the fixed part; the brake B4 is used to connect the sun gear of the second planetary gear mechanism to the fixed part; the brake B5 is used to connect the sun gear of the third planetary gear mechanism to the fixed part; the brake B6 is used to connect the ring gear of the third planetary gear mechanism to the fixed part; the brake B7 is used to connect the sun gear of the fourth planetary gear mechanism to the fixed part; the brake B8 is used to connect the ring gear of the fourth planetary gear mechanism to the fixed part.

[0013] Furthermore, by adjusting the displacement ratio of the hydraulic transmission device and by selectively controlling the engagement of the clutch assembly, the brake assembly and the synchronizer assembly, the transmission modes of the engine and / or the motor and the first output shaft and / or the second output shaft include: hydraulic transmission, engine-driven mechanical transmission, motor-driven mechanical transmission, engine and hydraulic compound transmission, and engine and motor coupled transmission.

[0014] Further, the first clutch CL1, the third clutch CL3, the fifth clutch CL5, the brake B1 and the brake B3 are engaged to provide hydraulic transmission between the engine and the second output shaft;

[0015] Engaging the first clutch CL1 , the third clutch CL3 , the fifth clutch CL5 , the seventh clutch CL7 , the brake B1 , and the brake B3 to provide hydraulic transmission between the engine and the first output shaft and the second output shaft;

[0016] The first clutch CL1 , the third clutch CL3 , the fifth clutch CL5 , the sixth clutch CL6 , the brake B1 , and the brake B4 are engaged to provide hydraulic transmission between the engine and the first output shaft.

[0017] Further, the second clutch CL2, the brake B3 and the brake B7 are engaged to provide a motor-driven mechanical transmission between the motor and the second output shaft;

[0018] Engaging the second clutch CL2, the seventh clutch CL7, the brake B3 and the brake B7 to provide a motor-driven mechanical transmission between the motor and the first output shaft and the second output shaft;

[0019] Engaging the second clutch CL2, the sixth clutch CL6, the brake B3 and the brake B7 to provide a motor-driven mechanical transmission between the motor and the first output shaft;

[0020] Further, the first clutch CL1, brake B1, brake B3 and brake B8 are engaged, and the first synchronizer S1 and brake B5, or the second synchronizer S2 and brake B6 are selectively engaged to provide an engine-driven mechanical transmission with different gear ratios between the engine and the second output shaft;

[0021] Engaging the first clutch CL1, the seventh clutch CL7, the brake B1, the brake B3 and the brake B8, and selectively engaging the first synchronizer S1 and the brake B5, or the second synchronizer S2 and the brake B6, to provide an engine-driven mechanical transmission with different gear ratios between the engine and the first output shaft and the second output shaft;

[0022] Engaging the first clutch CL1, the sixth clutch CL6, the brake B1, the brake B4 and the brake B8, and selectively engaging the first synchronizer S1 and the brake B5, or the second synchronizer S2 and the brake B6, provides engine-driven mechanical transmission with different gear ratios between the engine and the first output shaft.

[0023] Further, the first clutch CL1, the third clutch CL3, the fifth clutch CL5, the brake B1, the brake B3 and the brake B8 are engaged, and the first synchronizer S1 and the brake B5, or the second synchronizer S2 and the brake B6 are selectively engaged to provide an engine and hydraulic compound transmission with different gear ratios between the engine and the second output shaft;

[0024] Engage the first clutch CL1, the third clutch CL3, the fifth clutch CL5, the seventh clutch CL7, the brake B1, the brake B3 and the brake B8, and selectively engage the first synchronizer S1 and the brake B5, or the second synchronizer S2 and the brake B6, to provide an engine and hydraulic compound transmission with different gear ratios between the engine and the first output shaft and the second output shaft;

[0025] Engaging the first clutch CL1, the third clutch CL3, the fifth clutch CL5, the sixth clutch CL6, the brake B1, the brake B4 and the brake B8, and selectively engaging the first synchronizer S1 and the brake B5, or the second synchronizer S2 and the brake B6, provides an engine and hydraulic compound transmission with different gear ratios between the engine and the first output shaft.

[0026] Further, the first clutch CL1, the second clutch CL2, the brake B1 and the brake B3 are engaged, and the first synchronizer S1 and the brake B5, or the second synchronizer S2 and the brake B6 are selectively engaged to provide an engine-motor coupling transmission with different gear ratios between the engine and the motor and the second output shaft;

[0027] Engage the first clutch CL1, the second clutch CL2, the seventh clutch CL7, the brake B1 and the brake B3, and selectively engage the first synchronizer S1 and the brake B5, or the second synchronizer S2 and the brake B6, to provide an engine-motor coupling transmission with different gear ratios between the engine and the motor and the first output shaft and the second output shaft;

[0028] Engaging the first clutch CL1, the second clutch CL2, the sixth clutch CL6, the brake B1 and the brake B4, and selectively engaging the first synchronizer S1 and the brake B5, or the second synchronizer S2 and the brake B6, provides an engine and motor coupling transmission with different gear ratios between the engine and the motor and the first output shaft.

[0029] Further, by selectively engaging the first clutch CL1 , the fourth clutch CL4 , and the brake B2 , a charging transmission between the engine and the motor is provided;

[0030] By selectively engaging the second clutch CL2 , the brake B3 and the brake B7 , a braking energy recovery transmission between the second output shaft and the motor is provided.

[0031] A control method for a hydraulic-mechanical compound transmission system of a hybrid tractor comprises the following steps:

[0032] The vehicle controller collects the battery SOC, required torque T req , Braking torque T bre , vehicle speed v, a direction change signal of a transmission controller and a gear shift signal of a transmission controller;

[0033] When v = 0, it is in parking state. If the total output shaft torque T out >0, the vehicle controller controls the first output shaft to output power; if the total output shaft torque T out ≤0, and SOC≤SOC min When the vehicle controller controls the engine and the motor to form a charging transmission; SOC min is the minimum battery state of charge;

[0034] When v>0, it is in the running state. If SOC max ≤SOC, and the maximum torque of the motor Tmotmax>T reqWhen the vehicle controller controls the motor and the first output shaft or / and the second output shaft to form a motor-driven mechanical transmission; if SOC max ≤SOC, and the maximum torque of the motor Tmotmax≤T req When the vehicle controller controls the engine and the motor to form an engine and motor coupling transmission with the first output shaft or / and the second output shaft; if SOC max >SOC, and braking torque T bre >0, the vehicle controller controls the second output shaft to form a braking energy recovery transmission with the motor; if SOC max >SOC, and braking torque T bre <0, and T req ≤When the engine optimal torque TICE_best, the vehicle controller controls the tractor to stop, and the vehicle controller controls the engine and the motor to form a charging transmission;

[0035] When v>0 and receives the reversing signal or the gear shifting signal from the transmission controller, if T req ≤ the first set value, the vehicle controller controls the engine and the first output shaft or / and the second output shaft to form a hydraulic transmission; if the second set value>T req >When the first setting value is reached, the vehicle controller controls the engine and the first output shaft or / and the second output shaft to form an engine and hydraulic compound transmission; if T req >When the second set value is reached, the vehicle controller controls the engine and the first output shaft and / or the second output shaft to form an engine-driven mechanical transmission.

[0036] The beneficial effects of the present invention are:

[0037] 1. The hydraulic-mechanical composite transmission system of the hybrid tractor of the present invention comprises hydraulic transmission and mechanical transmission, and can realize different transmission modes. When direction-changing and gear-shifting are required, hydraulic transmission is used to realize uninterrupted gear-shifting power, thereby reducing the complexity of the transmission system. The stability of the hydraulic transmission improves the driving experience of the driver, and a variety of transmission modes meet the multi-operating and transportation requirements of the tractor.

[0038] 2. The hydraulic-mechanical compound transmission system of the hybrid tractor described in the present invention realizes stepless speed regulation through the motor and the hydraulic motor. When the motor outputs power, hydraulic transmission is not required. When the motor does not output power, the hydraulic motor performs stepless speed regulation, thereby realizing the continuity of the stepless speed regulation function. Compared with the multi-motor hybrid power system, the system has a simple structure, low cost and small energy loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. The drawings described below are some embodiments of the present invention. For ordinary technicians in this field, it is obvious that other drawings can be obtained based on these drawings without paying any creative work.

[0040] Figure 1 The schematic diagram of the hydraulic-mechanical compound transmission system of the hybrid power tractor described in the present invention.

[0041] Figure 2 A schematic diagram of the transmission path of the motor-driven mechanical transmission according to the present invention.

[0042] Figure 3 This is a second schematic diagram of the transmission path of the motor-driven mechanical transmission according to the present invention.

[0043] Figure 4 Schematic diagram of the transmission path of the motor-driven mechanical transmission according to the present invention.

[0044] Figure 5 It is a schematic diagram of the transmission path of the engine driven mechanical transmission gear I according to the present invention.

[0045] Figure 6 This is a second schematic diagram of the transmission path of the engine driven mechanical transmission gear I according to the present invention.

[0046] Figure 7 Schematic diagram of the transmission path of the engine driven mechanical transmission gear I described in the present invention.

[0047] Figure 8 It is a schematic diagram of the transmission path of the engine and the hydraulic compound transmission I gear according to the present invention.

[0048] Fig. 9 This is a second schematic diagram of the transmission path of the engine and hydraulic compound transmission I gear according to the present invention.

[0049] Fig.10 It is a schematic diagram of the transmission path of the engine and the hydraulic compound transmission gear I described in the present invention.

[0050] Fig.11 It is a schematic diagram of the transmission path of the engine and electric motor coupling transmission gear I described in the present invention.

[0051] Fig.12 This is a second schematic diagram of the transmission path of the engine and electric motor coupled transmission gear I described in the present invention.

[0052] Fig.13 Schematic diagram of the transmission path of the engine and electric motor coupling transmission gear I described in the present invention.

[0053] Fig.14 It is a schematic diagram of the transmission path of the engine driven mechanical transmission II gear according to the present invention.

[0054] Fig.15 This is a second schematic diagram of the transmission path of the engine driven mechanical transmission gear II according to the present invention.

[0055] Fig.16 This is a third schematic diagram of the transmission path of the engine driven mechanical transmission II gear according to the present invention.

[0056] Fig.17 It is a schematic diagram of the transmission path of the engine and the hydraulic compound transmission II gear according to the present invention.

[0057] Fig.18 It is a second schematic diagram of the transmission path of the engine and the hydraulic compound transmission II gear according to the present invention.

[0058] Fig.19 It is a third schematic diagram of the transmission path of the engine and the hydraulic compound transmission II gear according to the present invention.

[0059] Fig. 20 It is a schematic diagram of the transmission path of the engine and electric motor coupling transmission II gear described in the present invention.

[0060] Fig.21 It is a second schematic diagram of the transmission path of the engine and electric motor coupled transmission gear II described in the present invention.

[0061] Fig. 22 The third schematic diagram is a transmission path diagram of the engine and electric motor coupling transmission II gear described in the present invention.

[0062] Fig.23 It is a schematic diagram of the transmission path of the hydraulic transmission described in the present invention.

[0063] Fig.24 This is a second schematic diagram of the transmission path of the hydraulic transmission described in the present invention.

[0064] Fig.25 Schematic diagram of the transmission path of the hydraulic transmission described in the present invention.

[0065] Fig.26 This is a schematic diagram of the transmission path for the engine of the present invention to charge the battery.

[0066] Fig. 27 This is a schematic diagram of the transmission path of the braking energy recovery described in the present invention.

[0067] Fig.28 This is a control flow chart of the hydraulic-mechanical compound transmission system of the hybrid power tractor described in the present invention.

[0068] In the figure:

[0069] 1-engine; 2-vehicle controller; 3-battery; 4-motor; 5-transmission system; 5-1-first power input shaft; 5-2-first planetary gear mechanism; 5-2-1-first transmission gear pair; 5-2-2-second transmission gear pair; 5-3-hydraulic transmission device; 5-3-1-hydraulic transmission output gear pair; 5-3-2-hydraulic transmission shaft; 5-3-3-hydraulic pump; 5-3-4-hydraulic motor; 5-4-mechanical transmission device; 5-4-1-engine Ⅰ gear pair; 5-4-2-shift shaft three; 5-4-3-shift shaft one; 5-4-4-third planetary gear mechanism; 5-4-5-third transmission gear pair; 5-4-6-engine gear pair for gear II; 5-4-7-fourth planetary gear mechanism; 5-4-8-first bevel gear pair; 5-4-10-shift shaft two; 5-4-9-second bevel gear pair; 6-total power output shaft; 7-second planetary gear mechanism; 7-1-fourth transmission gear pair; 8-first output shaft; 9-second output shaft. DETAILED DESCRIPTION

[0070] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

[0071] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0072] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "axial", "radial", "vertical", "horizontal", "inner", "outer" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0073] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0074] like Figure 1 As shown, the hydraulic-mechanical compound transmission system of the hybrid tractor of the present invention comprises an engine 1, a vehicle controller 2, a motor 4, a transmission system 5, a second planetary gear mechanism 7, a total power output shaft 6, a second planetary gear mechanism 7, a first output shaft 8, a second output shaft 9, a clutch assembly, a brake assembly and a synchronizer assembly;

[0075] The battery 3 is connected to the motor 4; the motor 4 is an integrated electric / generator motor; the transmission system includes a first power input shaft 5-1, a first planetary gear mechanism 5-2, a hydraulic transmission device 5-3 and a mechanical transmission device 5-4; the first power input shaft 5-1 is connected to the planetary carrier of the first planetary gear mechanism 5-2; the hydraulic transmission device 5-3 includes a hydraulic transmission output gear pair 5-3-1, a hydraulic transmission shaft 5-3-2, a hydraulic pump 5-3-3 and a hydraulic motor 5-3-4; the ring gear of the first planetary gear mechanism 5-2 is connected to the hydraulic transmission shaft 5-3-2 through the first transmission gear pair 5-2-1, the hydraulic transmission shaft 5-3-2 is connected to the input end of the hydraulic pump 5-3-3, the hydraulic pump 5-3-3 is connected to the hydraulic motor 5-3-4, and the output shaft of the hydraulic motor 5-3-4 is connected to the total power output shaft 6 through the hydraulic transmission output gear pair 5-3-1.

[0076] The mechanical transmission device 5-4 includes an engine first gear pair 5-4-1, a third gear shift shaft 5-4-2, a first gear shift shaft 5-4-3, a third planetary gear mechanism 5-4-4, a third transmission gear pair 5-4-5, an engine second gear pair 5-4-6, a fourth planetary gear mechanism 5-4-7, a first bevel gear pair 5-4-8, a second gear shift shaft 5-4-10 and a second bevel gear pair 5-4-9; the sun gear of the first planetary gear mechanism 5-2 is connected to the second bevel gear pair 5-4-11. -4-9 is connected to the shift shaft 3 5-4-2, the shift shaft 1 5-4-3 is connected to the ring gear of the third planetary gear mechanism 5-4-4; the planet carrier of the third planetary gear mechanism 5-4-4 is connected to the sun gear of the fourth planetary gear mechanism 5-4-7 through the first bevel gear pair 5-4-8; the planet carrier of the fourth planetary gear mechanism 5-4-7 is connected to the total power output shaft 6, and the shift shaft 2 5-4-10 is connected to the sun gear of the third planetary gear mechanism 5-4-4;

[0077] The planet carrier of the second planetary gear mechanism 7 is connected to the total power output shaft 6, the ring gear of the second planetary gear mechanism 7 is connected to the first output shaft 8 through the fourth transmission gear pair 7-1, the sun gear of the second planetary gear mechanism 7 is connected to the second output shaft 9, and the second output shaft 9 is connected to the first output shaft 8 through a transmission gear.

[0078] The clutch assembly includes a first clutch CL1, a second clutch CL2, a third clutch CL3, a fourth clutch CL4, a fifth clutch CL5, a sixth clutch CL6 and a seventh clutch CL7; the first clutch CL1 is used to selectively connect the output shaft of the engine 1 with the planetary carrier of the first planetary gear mechanism 5-2; the second clutch CL2 is used to selectively connect the output shaft of the motor 4 with the ring gear of the fourth planetary gear mechanism 5-4-7; the third clutch CL3 is used to selectively connect the sun gear of the first planetary gear mechanism 5-2 with the input end of the hydraulic transmission device 5-3; the fourth clutch CL4 is used to selectively connect the output shaft of the motor 4 with the ring gear of the first planetary gear mechanism 5-2; the fifth clutch CL5 is used to selectively connect the output end of the hydraulic transmission device 5-3 with the total power output shaft 6; the sixth clutch CL6 is used to selectively connect the first output shaft 8 with the ring gear of the second planetary gear mechanism 7; the seventh clutch CL7 is used to selectively connect the first output shaft 8 with the second output shaft 9;

[0079] The synchronizer assembly includes a first synchronizer S1 and a second synchronizer S2. The first synchronizer S1 is used to selectively synchronize the shift shaft 5-4-2 with the shift shaft 1 5-4-3 through the engine gear pair 5-4-1; the second synchronizer S2 is used to selectively synchronize the shift shaft 5-4-2 with the sun gear of the third planetary gear mechanism 5-4-4 through the engine gear pair 5-4-6.

[0080] The brake assembly includes brake B1, brake B2, brake B3, brake B4, brake B5, brake B6, brake B7 and brake B8; the brake B1 is used to connect the ring gear of the first planetary gear mechanism 5-2 to the fixed part; the brake B2 is used to connect the sun gear of the first planetary gear mechanism 5-2 to the fixed part; the brake B3 is used to connect the ring gear of the second planetary gear mechanism 7 to the fixed part; the brake B4 is used to connect the sun gear of the second planetary gear mechanism 7 to the fixed part; the brake B5 is used to connect the sun gear of the third planetary gear mechanism 5-4-4 to the fixed part; the brake B6 is used to connect the ring gear of the third planetary gear mechanism 5-4-4 to the fixed part; the brake B7 is used to connect the sun gear of the fourth planetary gear mechanism 5-4-7 to the fixed part; the brake B8 is used to connect the ring gear of the fourth planetary gear mechanism 5-4-7 to the fixed part.

[0081] The displacement ratio of the hydraulic transmission device 5-3 is adjusted by the vehicle controller 2, and the engagement of the clutch assembly, brake assembly and synchronizer assembly is selectively controlled by the vehicle controller 2, and the transmission mode provided between the engine 1 and / or the motor 4 and the first output shaft 8 and / or the second output shaft 9 includes: hydraulic transmission, mechanical transmission driven by the engine, mechanical transmission driven by the motor, engine and hydraulic compound transmission, engine and motor coupling transmission. The vehicle controller 2 collects the battery SOC, vehicle speed, and output shaft torque of the hybrid tractor, and distributes the torque of the engine and the motor according to the required torque.

[0082] Mechanical transmission method driven by electric motor, such as Figure 2 As shown, the second clutch CL2, brake B3 and brake B7 are engaged, the battery 3 outputs electric energy to the motor 4, and the motor 4 is started as a motor; the power output by the motor 4 is transmitted to the ring gear of the fourth planetary gear mechanism 5-4-7 through the third transmission gear pair 5-4-5, and then output to the total power output shaft 6 by the planet carrier of the fourth planetary gear 5-4-7, and then to the planet carrier of the second planetary gear mechanism 7, and then output to the second output shaft 9 through the sun gear of the second planetary gear mechanism 7, and then transmitted to the differential by the second output shaft 9, and finally reaches the drive wheel. The mechanical transmission mode driven by the motor outputs power through the second output shaft 9.

[0083] The second mechanical transmission method driven by the motor is as follows: Figure 3 As shown, the second clutch CL2, the seventh clutch CL7, the brake B3 and the brake B7 are engaged, and the second mechanical transmission mode driven by the motor outputs power through the second output shaft 9 and the first output shaft 8 respectively.

[0084] Three mechanical transmission modes driven by electric motors, such as Figure 4 As shown, the second clutch CL2, the sixth clutch CL6, the brake B3 and the brake B7 are engaged, and the motor-driven mechanical transmission mode three outputs power through the first output shaft 8, which is generally used for parking power output.

[0085] Engine driven mechanical transmission Ⅰ gear transmission mode 1, such as Figure 5 As shown, the first clutch CL1, the first synchronizer S1, the brake B5, the brake B1, the brake B3 and the brake B8 are engaged, the power output by the engine 1 is transmitted to the planetary carrier of the first planetary gear mechanism 5-2 via the first power input shaft 5-1, and then the power output by the sun gear of the first planetary gear mechanism 5-2 is transmitted to the shift shaft 5-4-2 via the second bevel gear pair 5-4-9, and then input to the shift shaft 1 5-4-3 via the engine Ⅰ gear pair 5-4-1, and then transmitted to the shift shaft 1 5-4-3 via the shift shaft 1 5-4 -3 is transmitted to the ring gear of the third planetary gear mechanism 5-4-4, and then output by the planet carrier of the third planetary gear mechanism 5-4-4, through the first bevel gear pair 5-4-8 to the sun gear of the fourth planetary gear mechanism 5-4-7, and then output by the planet carrier of the fourth planetary gear mechanism 5-4-7 to the total power output shaft 6, and then to the planet carrier of the second planetary gear mechanism 7, and output to the second output shaft 9 through the sun gear of the second planetary gear mechanism 7, and then transmitted to the differential by the second output shaft 9, and finally reaches the drive wheel. The engine drives the mechanical transmission I gear transmission mode 1 to output power through the second output shaft 9.

[0086] Engine driven mechanical transmission Ⅰ gear transmission mode 2, such as Figure 6 As shown, the first clutch CL1, the seventh clutch CL7, the first synchronizer S1, the brake B5, the brake B1, the brake B3 and the brake B8 are engaged, and the engine drives the mechanical I gear transmission mode 2 to output power through the second output shaft 9 and the first output shaft 8 respectively.

[0087] Engine driven mechanical transmission Ⅰ gear transmission mode three, such as Figure 7 As shown, the first clutch CL1, the sixth clutch CL6, the first synchronizer S1, the brake B5, the brake B1, the brake B4 and the brake B8 are engaged, and the engine drives the mechanical transmission I gear transmission mode three to output power through the first output shaft 8, which is generally used for parking power output.

[0088] Engine and hydraulic compound transmission Ⅰ gear transmission mode 1, such as Figure 8 As shown, the first clutch CL1, the third clutch CL3, the fifth clutch CL5, the first synchronizer S1, the brake B5, the brake B1, the brake B3 and the brake B8 are engaged, the power output by the engine 1 is transmitted to the planetary carrier of the first planetary gear mechanism 5-2 via the first power input shaft 5-1, and then the power of two different branches output by the sun gear of the first planetary gear mechanism 5-2, one branch is transmitted to the shift shaft 5-4-2 via the second bevel gear pair 5-4-9, and then input to the shift shaft 1 5-4-3 via the engine Ⅰ gear pair 5-4-1, and then transmitted to the gear ring of the third planetary gear mechanism 5-4-4 via the shift shaft 1 5-4-3, and then The power is outputted from the planet carrier of the third planetary gear mechanism 5-4-4, through the first bevel gear pair 5-4-8 to the sun gear of the fourth planetary gear mechanism 5-4-7, and then from the planet carrier of the fourth planetary gear mechanism 5-4-7 to the total power output shaft 6. Another branch is transmitted to the variable pump 5-3-3 and the hydraulic motor 5-3-4 through the hydraulic transmission shaft. The output of the hydraulic motor is then transmitted to the total power output shaft 6 through the hydraulic transmission output gear pair; the two parts of power converge to the total power output shaft 6, and then to the planet carrier of the second planetary gear mechanism 7, and then to the second output shaft 9 through the sun gear of the second planetary gear mechanism 7, and then to the differential from the second output shaft 9, and finally to the drive wheel. The engine and hydraulic compound transmission Ⅰ gear transmission mode 1 outputs power through the second output shaft 9.

[0089] Engine and hydraulic compound transmission Ⅰ gear transmission mode 2, such as Fig. 9 As shown, the first clutch CL1, the third clutch CL3, the fifth clutch CL5, the seventh clutch CL7, the first synchronizer S1, the brake B5, the brake B1, the brake B3 and the brake B8 are engaged, and the engine and the hydraulic compound transmission Ⅰ gear transmission mode 2 output power through the second output shaft 9 and the first output shaft 8 respectively.

[0090] Engine and hydraulic compound transmission Ⅰ gear transmission mode three, such as Fig.10 As shown, the first clutch CL1, the third clutch CL3, the fifth clutch CL5, the sixth clutch CL6, the first synchronizer S1, the brake B5, the brake B1, the brake B4 and the brake B8 are engaged, and the engine and the hydraulic compound transmission Ⅰ gear transmission mode 3 output power through the first output shaft 8, which is generally used for parking power output.

[0091] The engine and the electric motor are coupled to drive the I gear transmission mode 1, such as Fig.11As shown, the first clutch CL1, the second clutch CL2, the first synchronizer S1, the brake B5, the brake B1 and the brake B3 are engaged, the power output by the engine 1 is transmitted to the planetary carrier of the first planetary gear mechanism 5-2 via the first power input shaft 5-1, and then the power output by the sun gear of the first planetary gear mechanism 5-2 is transmitted to the shift shaft 5-4-2 via the second bevel gear pair 5-4-9, and then input to the shift shaft 1 5-4-3 via the engine Ⅰ gear pair 5-4-1, and then transmitted to the gear ring of the third planetary gear mechanism 5-4-4 via the shift shaft 1 5-4-3. Then the power is outputted by the planet carrier of the third planetary gear mechanism 5-4-4, and then transmitted to the sun gear of the fourth planetary gear mechanism 5-4-7 through the first bevel gear pair 5-4-8. The power outputted by the motor 4 is transmitted to the ring gear of the fourth planetary gear mechanism 5-4-7 through the third transmission gear pair 5-4-5. The power of the engine and the motor is coupled by the fourth planetary gear mechanism and then outputted by the planet carrier to the total power output shaft 6, and then to the planet carrier of the second planetary gear mechanism 7, and then outputted to the second output shaft 9 through the sun gear of the second planetary gear mechanism 7, and then transmitted to the differential by the second output shaft 9, and finally reaches the drive wheel. The engine and the motor are coupled to drive the I gear transmission mode and output the power through the second output shaft 9.

[0092] The engine and the electric motor are coupled to drive the first gear. The second transmission mode is as follows: Fig.12 As shown, the first clutch CL1, the second clutch CL2, the seventh clutch CL7, the first synchronizer S1, the brake B5, the brake B1 and the brake B3 are engaged, and the engine and the motor are coupled to transmit the I gear transmission mode 2 to output power through the second output shaft 9 and the first output shaft 8 respectively.

[0093] The engine and the electric motor are coupled to drive the first gear transmission mode three, such as Fig.13 As shown, the first clutch CL1, the second clutch CL2, the sixth clutch CL6, the first synchronizer S1, the brake B5, the brake B1 and the brake B4 are engaged, and the engine and the motor are coupled to transmit the I gear transmission mode 3 to output power through the first output shaft 8, which is generally used for parking power output.

[0094] Engine driven mechanical transmission II gear transmission mode 1, such as Fig.14As shown, the first clutch CL1, the second synchronizer S2, the brake B6, the brake B1, the brake B3 and the brake B8 are engaged, and the power output by the engine 1 is transmitted to the planetary carrier of the first planetary gear mechanism 5-2 via the first power input shaft 5-1, and then the power output by the sun gear of the first planetary gear mechanism 5-2 is transmitted to the shift shaft 5-4-2 via the second bevel gear pair 5-4-9, and then input into the sun gear of the third planetary gear mechanism 5-4-4 via the engine II gear pair 5-4-6, and then output from the planetary carrier of the third planetary gear mechanism 5-4-4, through the first bevel gear pair 5-4-8 to the sun gear of the fourth planetary gear mechanism 5-4-7, and then output from the planetary carrier of the fourth planetary gear mechanism 5-4-7 to the total power output shaft 6, and then to the planetary carrier of the second planetary gear mechanism 7, and then output to the second output shaft 9 via the sun gear of the second planetary gear mechanism 7, and then transmitted to the differential by the second output shaft 9, and finally reaches the drive wheel. The engine drives the mechanical transmission II gear transmission mode 1 to output power through the second output shaft 9.

[0095] Engine driven mechanical transmission Ⅱ gear transmission mode 2, such as Fig.15 As shown, the first clutch CL1, the seventh clutch CL7, the second synchronizer S2, the brake B6, the brake B1, the brake B3 and the brake B8 are engaged, and the engine drives the mechanical transmission II gear transmission mode 2 to output power through the second output shaft 9 and the first output shaft 8 respectively.

[0096] Engine driven mechanical transmission II gear transmission mode three, such as Fig.16 As shown, the first clutch CL1, the sixth clutch CL6, the second synchronizer S2, the brake B6, the brake B1, the brake B4 and the brake B8 are engaged, and the engine drives the mechanical transmission II gear transmission mode three to output power through the first output shaft 8, which is generally used for parking output power.

[0097] Engine and hydraulic compound transmission Ⅱ gear transmission mode 1, such as Fig.17As shown, the first clutch CL1, the third clutch CL3, the fifth clutch CL5, the second synchronizer S2, the brake B6, the brake B1, the brake B3 and the brake B8 are engaged, the power output by the engine 1 is transmitted to the planetary carrier of the first planetary gear mechanism 5-2 via the first power input shaft 5-1, and then the power of two different branches output by the sun gear of the first planetary gear mechanism 5-2, one branch is transmitted to the shift shaft 5-4-2 via the second bevel gear pair 5-4-9, and then input to the sun gear of the third planetary gear mechanism 5-4-4 via the engine II gear pair 5-4-6, and then the power of the third planetary gear mechanism 5-4 -4 planetary carrier output, through the first bevel gear pair 5-4-8 to the sun gear of the fourth planetary gear mechanism 5-4-7, and then from the planetary carrier of the fourth planetary gear mechanism 5-4-7 to the total power output shaft 6, the other branch is transmitted to the variable pump 5-3-3 and the hydraulic motor 5-3-4 through the hydraulic transmission shaft, and the hydraulic motor output is then transmitted to the total power output shaft 6 through the hydraulic transmission output gear pair; the two parts of power converge to the total power output shaft 6, and then to the planetary carrier of the second planetary gear mechanism 7, and then output to the second output shaft 9 through the sun gear of the second planetary gear mechanism 7, and then from the second output shaft 9 to the differential, and finally to the drive wheel. The engine and hydraulic compound transmission II gear transmission mode 1 outputs power through the second output shaft 9.

[0098] Engine and hydraulic compound transmission Ⅱ gear transmission mode 2, such as Fig.18 As shown, the first clutch CL1, the third clutch CL3, the fifth clutch CL5, the seventh clutch CL7, the second synchronizer S2, the brake B6, the brake B1, the brake B3 and the brake B8 are engaged, and the engine and the hydraulic compound transmission II gear transmission mode 2 output power through the second output shaft 9 and the first output shaft 8 respectively.

[0099] Engine and hydraulic compound transmission II gear transmission mode three, such as Fig.19 As shown, the first clutch CL1, the third clutch CL3, the fifth clutch CL5, the sixth clutch CL6, the second synchronizer S2, the brake B6, the brake B1, the brake B4 and the brake B8 are engaged, and the engine and the hydraulic compound transmission II gear transmission mode three output power through the first output shaft 8, which is generally used for parking output power.

[0100] The engine and the electric motor are coupled to drive the Ⅱ gear transmission mode 1, such as Fig. 20As shown, the first clutch CL1, the second clutch CL2, the second synchronizer S2, the brake B6, the brake B1 and the brake B3 are engaged, the power output by the engine 1 is transmitted to the planetary carrier of the first planetary gear mechanism 5-2 through the first power input shaft 5-1, and then the power output by the sun gear of the first planetary gear mechanism 5-2 is transmitted to the shift shaft 5-4-2 through the second bevel gear pair 5-4-9, and then input to the sun gear of the third planetary gear mechanism 5-4-4 through the engine II gear pair 5-4-6, and then transmitted to the third planetary gear mechanism 5- The power output of the planetary carrier of 4-4 is transmitted to the sun gear of the fourth planetary gear mechanism 5-4-7 through the first bevel gear pair 5-4-8. The power output of the motor 4 is transmitted to the ring gear of the fourth planetary gear mechanism 5-4-7 through the third transmission gear pair 5-4-5. The power of the engine and the motor is coupled through the fourth planetary gear mechanism and output from the planetary carrier to the total power output shaft 6, and then to the planetary carrier of the second planetary gear mechanism 7, and output to the second output shaft 9 through the sun gear of the second planetary gear mechanism 7, and then transmitted from the second output shaft 9 to the differential, and finally reaches the drive wheel. The engine and the motor are coupled to the transmission II gear transmission mode 1 to output power through the second output shaft 9.

[0101] The engine and the electric motor are coupled to drive the Ⅱ gear transmission mode 2, such as Fig.21 As shown, the first clutch CL1, the second clutch CL2, the seventh clutch CL7, the second synchronizer S2, the brake B6, the brake B1 and the brake B3 are engaged, and the engine and the motor are coupled to transmit the transmission II gear mode 2 to output power through the second output shaft 9 and the first output shaft 8 respectively.

[0102] The engine and the electric motor are coupled to drive the Ⅱ gear transmission mode 3, such as Fig. 22 As shown, the first clutch CL1, the second clutch CL2, the sixth clutch CL6, the second synchronizer S2, the brake B6, the brake B1 and the brake B4 are engaged, and the engine and the motor are coupled to transmit the transmission II gear transmission mode three to output power through the first output shaft 8, which is generally used for parking output power.

[0103] Hydraulic transmission method 1, such as Fig.23As shown, the first clutch CL1, the third clutch CL3, the fifth clutch CL5, the brake B1 and the brake B3 are engaged, the power output by the engine 1 is transmitted to the planet carrier of the first planetary gear mechanism 5-2 through the first power input shaft 5-1, the sun gear of the first planetary gear mechanism 5-2 is connected to the hydraulic transmission shaft 5-3-2 through the first transmission gear pair 5-2-1, and transmitted to the variable pump 5-3-3 and the hydraulic motor 5-3-4 through the hydraulic transmission shaft 5-3-2, and the hydraulic motor output is then transmitted to the total power output shaft 6 through the hydraulic transmission output gear pair 5-3-1; then to the planet carrier of the second planetary gear mechanism 7, and output to the second output shaft 9 through the sun gear of the second planetary gear mechanism 7, and then transmitted to the differential by the second output shaft 9, and finally reaches the drive wheel. Hydraulic transmission mode 1 outputs power through the second output shaft 9.

[0104] Hydraulic transmission method 2, such as Fig.24 As shown, the first clutch CL1, the third clutch CL3, the fifth clutch CL5, the seventh clutch CL7, the brake B1 and the brake B3 are engaged, and the hydraulic transmission mode 2 outputs power through the second output shaft 9 and the first output shaft 8 respectively.

[0105] Hydraulic transmission method three, such as Fig.25 As shown, the first clutch CL1, the third clutch CL3, the fifth clutch CL5, the sixth clutch CL6, the brake B1 and the brake B4 are engaged, and the hydraulic transmission mode three outputs power through the first output shaft 8, which is generally used for parking power output.

[0106] The engine charges the battery Fig.26 As shown, the first clutch CL1, the fourth clutch CL4 and the brake B2 are engaged, the engine 1 is started, and the motor 2 is started as a generator. The power output by the engine 1 is transmitted through the first power input shaft 5-1 to the planetary carrier of the first planetary gear mechanism 5-2. The ring gear of the first planetary gear mechanism 5-2 transmits the power to the generator through the second transmission gear pair 5-2-2. The electric energy generated by the generator is output to the battery 3.

[0107] Hybrid tractor brake energy recovery Fig. 27 As shown, the second clutch CL2, brake B3 and brake B7 are engaged. When the tractor brakes or decelerates, the power is transmitted to the second output shaft 9 through the differential, and then to the sun gear of the second planetary gear mechanism 7, and then output to the total power output shaft 6 by the planetary carrier, and then to the planetary carrier of the fourth planetary gear mechanism 5-4-7. The ring gear of the fourth planetary gear mechanism 5-4-7 transmits the power to the motor 4 through the third transmission gear pair 5-4-5, and the electric energy generated by the motor is output to the battery 3.

[0108] like Fig.28As shown, the control method of the hydraulic-mechanical compound transmission system of the hybrid tractor of the present invention comprises the following steps:

[0109] The vehicle controller 2 collects the battery SOC, required torque T req , Braking torque T bre , vehicle speed v, a direction change signal of a transmission controller and a gear shift signal of a transmission controller;

[0110] When v = 0, it is in parking state. If the total output shaft torque T out >0, the vehicle controller 2 controls the first output shaft 8 to output power; if the total output shaft torque T out ≤0, and SOC≤SOC min When SOC is on, the vehicle controller 2 controls the engine 1 and the motor 4 to form a charging transmission; min is the minimum battery state of charge;

[0111] When v>0, it is in the running state. If SOC max ≤SOC, and the maximum torque of the motor is T motmax >T req When SOC 2 controls the motor 4 and the first output shaft 8 or / and the second output shaft 9 to form a motor-driven mechanical transmission; if SOC max ≤SOC, and the maximum torque of the motor is T motmax ≤T req When the vehicle controller 2 controls the engine 1 and the motor 4 to form an engine-motor coupling transmission with the first output shaft 8 or / and the second output shaft 9, the engine-motor coupling transmission I gear transmission or the engine-motor coupling transmission II gear transmission is selected according to T req It is related to the torque of the Ⅰ gear transmission and the torque of the Ⅱ gear transmission; if SOC max >SOC, and braking torque T bre >0, the vehicle controller 2 controls the second output shaft 9 to form a braking energy recovery transmission with the motor 4; if SOC max >SOC, and braking torque T bre <0, and T req ≤ Engine optimum torque T ICE_best When SOC is on, the vehicle controller 2 controls the tractor to stop, and the vehicle controller 2 controls the engine 1 and the motor 4 to form a charging transmission; if SOC max >SOC, and braking torque T bre <0, and T req ≤ Engine optimum torque T ICE_best When the vehicle controller 2 controls the tractor to stop, the vehicle controller 2 controls the engine 1 and the motor 4 to form a charging transmission;

[0112] If SOCmax >SOC, and braking torque T bre <0, and T req >Engine Optimum Torque T ICE_best , and SOC min >SOC, the vehicle controller 2 controls the engine 1 and the first output shaft 8 and / or the second output shaft 9 to form an engine-only drive.

[0113] When v>0, when the vehicle controller receives the reversing signal or the shifting signal of the transmission controller, the vehicle controller 2 controls the engine 1 and the first output shaft 8 or / and the second output shaft 9 to form a hydraulic transmission; if the vehicle controller does not receive the reversing signal or the shifting signal of the transmission controller, if T req ≤ the first set value, the vehicle controller 2 controls the engine 1 to form a hydraulic transmission with the first output shaft 8 and / or the second output shaft 9; if the second set value>T req >When the first setting value is reached, the vehicle controller 2 controls the engine 1 and the first output shaft 8 or / and the second output shaft 9 to form an engine and hydraulic compound transmission, and the engine and hydraulic compound transmission Ⅰ gear transmission or the engine and hydraulic compound transmission Ⅱ gear transmission is selected according to T req It is related to the torque of the I gear transmission and the torque of the II gear transmission; if T req >When the second setting value is reached, the vehicle controller 2 controls the engine 1 and the first output shaft 8 or / and the second output shaft 9 to form an engine-driven mechanical transmission, and the engine-driven mechanical transmission I gear transmission or the engine-driven mechanical transmission II gear transmission is selected according to T req The second setting value and the first setting value are determined according to the torque of the hydraulic transmission and the torque of the engine and hydraulic compound transmission.

[0114] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0115] The series of detailed descriptions listed above are only specific descriptions of feasible embodiments of the present invention. They are not intended to limit the scope of protection of the present invention. All equivalent embodiments or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A hydraulic-mechanical compound transmission system for a hybrid tractor, characterized in that: The invention comprises an engine (1), a vehicle controller (2), a motor (4), a transmission system (5), a second planetary gear mechanism (7), a clutch assembly, a brake assembly and a synchronizer assembly, wherein the transmission system (5) comprises a first planetary gear mechanism (5-2), a hydraulic transmission device (5-3) and a mechanical transmission device (5-4); the first planetary gear mechanism (5-2) is connected to the hydraulic transmission device (5-3) and the mechanical transmission device (5-4) respectively, the hydraulic transmission device (5-3) and the mechanical transmission device (5-4) are connected to a total power output shaft (6) respectively; the total power output shaft (6) is connected to The second planetary gear mechanism (7) is connected to the first planetary gear mechanism (5-2) and the mechanical transmission device (5-4); the engine (1) is respectively connected to the first planetary gear mechanism (5-2) and the mechanical transmission device (5-4); the motor (4) is respectively connected to the first planetary gear mechanism (5-2) and the mechanical transmission device (5-4); the second planetary gear mechanism (7) is respectively connected to the first output shaft (8) and the second output shaft (9); the clutch assembly, the brake assembly and the synchronizer assembly are selectively controlled by the vehicle controller (2) to provide different transmission ratios between the engine (1) and / or the motor (4) and the first output shaft (8) and / or the second output shaft (9); The clutch assembly includes a first clutch CL1, a second clutch CL2, a third clutch CL3, a fifth clutch CL5, a sixth clutch CL6, and a seventh clutch CL7; The first clutch CL1 is used for selectively connecting the output shaft of the engine (1) to the planetary carrier of the first planetary gear mechanism (5-2); the third clutch CL3 is used for selectively connecting the sun gear of the first planetary gear mechanism (5-2) to the input end of the hydraulic transmission device (5-3); the fifth clutch CL5 is used for selectively connecting the output end of the hydraulic transmission device (5-3) to the total power output shaft (6); the sixth clutch CL6 is used for selectively connecting the first output shaft (8) to the ring gear of the second planetary gear mechanism (7); the seventh clutch CL7 is used for selectively connecting the first output shaft (8) to the second output shaft (9); The mechanical transmission device (5-4) comprises an engine first gear pair (5-4-1), a third gear shift shaft (5-4-2), a first gear shift shaft (5-4-3), a third planetary gear mechanism (5-4-4), a third transmission gear pair (5-4-5), an engine second gear pair (5-4-6), a fourth planetary gear mechanism (5-4-7), a first bevel gear pair (5-4-8), a second gear shift shaft (5-4-10) and a second bevel gear pair (5-4-9); the sun gear of the first planetary gear mechanism (5-2) is driven by the second bevel gear pair (5-4-11). 9) is connected to the shift shaft (5-4-2), the shift shaft (5-4-3) is connected to the ring gear of the third planetary gear mechanism (5-4-4); the planet carrier of the third planetary gear mechanism (5-4-4) is connected to the sun gear of the fourth planetary gear mechanism (5-4-7) through the first bevel gear pair (5-4-8); the planet carrier of the fourth planetary gear mechanism (5-4-7) is connected to the total power output shaft (6); the second clutch CL2 is used to selectively connect the output shaft of the motor (4) to the ring gear of the fourth planetary gear mechanism (5-4-7); The synchronizer assembly comprises a first synchronizer S1 and a second synchronizer S2, wherein the first synchronizer S1 is used to selectively synchronize the shift shaft (5-4-2) with the shift shaft (5-4-3) via the engine first gear pair (5-4-1); and the second synchronizer S2 is used to selectively synchronize the shift shaft (5-4-2) with the sun gear of the third planetary gear mechanism (5-4-4) via the engine second gear pair (5-4-6).

2. The hydraulic-mechanical compound transmission system of a hybrid tractor according to claim 1, characterized in that: The clutch assembly further comprises a fourth clutch CL4, the fourth clutch CL4 being used to selectively connect the output shaft of the motor (4) to the ring gear of the first planetary gear mechanism (5-2); the brake assembly comprises a brake B1, a brake B2, a brake B3, a brake B4, a brake B5, a brake B6, a brake B7 and a brake B8; the brake B1 is used to connect the ring gear of the first planetary gear mechanism (5-2) to the fixed part; the brake B2 is used to connect the sun gear of the first planetary gear mechanism (5-2) to the fixed part; the brake B3 is used to The brake B4 is used to connect the sun gear of the second planetary gear mechanism (7) to the fixed member; the brake B5 is used to connect the sun gear of the third planetary gear mechanism (5-4-4) to the fixed member; the brake B6 is used to connect the ring gear of the third planetary gear mechanism (5-4-4) to the fixed member; the brake B7 is used to connect the sun gear of the fourth planetary gear mechanism (5-4-7) to the fixed member; and the brake B8 is used to connect the ring gear of the fourth planetary gear mechanism (5-4-7) to the fixed member.

3. The hydraulic-mechanical compound transmission system of a hybrid tractor according to claim 2, characterized in that: By adjusting the displacement ratio of the hydraulic transmission device (5-3) and by selectively controlling the engagement of the clutch assembly, the brake assembly and the synchronizer assembly, a transmission mode between the engine (1) and / or the motor (4) and the first output shaft (8) and / or the second output shaft (9) is provided, including: hydraulic transmission, engine-driven mechanical transmission, motor-driven mechanical transmission, engine and hydraulic compound transmission, and engine and motor coupled transmission.

4. The hydraulic-mechanical compound transmission system of a hybrid tractor according to claim 3, characterized in that: Engaging the first clutch CL1, the third clutch CL3, the fifth clutch CL5, the brake B1 and the brake B3 to provide hydraulic transmission between the engine (1) and the second output shaft (9); Engaging the first clutch CL1, the third clutch CL3, the fifth clutch CL5, the seventh clutch CL7, the brake B1 and the brake B3 to provide hydraulic transmission between the engine (1) and the first output shaft (8) and the second output shaft (9); Engaging the first clutch CL1, the third clutch CL3, the fifth clutch CL5, the sixth clutch CL6, the brake B1 and the brake B4 to provide hydraulic transmission between the engine (1) and the first output shaft (8); Engaging the second clutch CL2, the brake B3 and the brake B7 to provide a motor-driven mechanical transmission between the motor (4) and the second output shaft (9); Engaging the second clutch CL2, the seventh clutch CL7, the brake B3 and the brake B7 to provide a motor-driven mechanical transmission between the motor (4) and the first output shaft (8) and the second output shaft (9); The second clutch CL2, the sixth clutch CL6, the brake B3 and the brake B7 are engaged to provide a motor-driven mechanical transmission between the motor (4) and the first output shaft (8).

5. The hydraulic-mechanical compound transmission system of a hybrid tractor according to claim 3, characterized in that: Engaging the first clutch CL1, brake B1, brake B3 and brake B8, and selectively engaging the first synchronizer S1 and brake B5, or the second synchronizer S2 and brake B6, to provide an engine-driven mechanical transmission with different gear ratios between the engine (1) and the second output shaft (9); Engaging the first clutch CL1, the seventh clutch CL7, the brake B1, the brake B3 and the brake B8, and selectively engaging the first synchronizer S1 and the brake B5, or the second synchronizer S2 and the brake B6, to provide an engine-driven mechanical transmission with different gear ratios between the engine (1) and the first output shaft (8) and the second output shaft (9); Engaging the first clutch CL1, the sixth clutch CL6, the brake B1, the brake B4 and the brake B8, and selectively engaging the first synchronizer S1 and the brake B5, or the second synchronizer S2 and the brake B6, provides an engine-driven mechanical transmission with different gear ratios between the engine (1) and the first output shaft (8).

6. The hydraulic-mechanical compound transmission system of a hybrid tractor according to claim 3, characterized in that: Engaging the first clutch CL1, the third clutch CL3, the fifth clutch CL5, the brake B1, the brake B3 and the brake B8, and selectively engaging the first synchronizer S1 and the brake B5, or the second synchronizer S2 and the brake B6, to provide an engine and hydraulic compound transmission with different gear ratios between the engine (1) and the second output shaft (9); Engaging the first clutch CL1, the third clutch CL3, the fifth clutch CL5, the seventh clutch CL7, the brake B1, the brake B3 and the brake B8, and selectively engaging the first synchronizer S1 and the brake B5, or the second synchronizer S2 and the brake B6, to provide an engine and hydraulic compound transmission with different gear ratios between the engine (1) and the first output shaft (8) and the second output shaft (9); The first clutch CL1, the third clutch CL3, the fifth clutch CL5, the sixth clutch CL6, the brake B1, the brake B4 and the brake B8 are engaged, and the first synchronizer S1 and the brake B5, or the second synchronizer S2 and the brake B6 are selectively engaged to provide an engine and hydraulic compound transmission with different gear ratios between the engine (1) and the first output shaft (8).

7. The hydraulic-mechanical compound transmission system of a hybrid tractor according to claim 3, characterized in that: Engaging the first clutch CL1, the second clutch CL2, the brake B1 and the brake B3, and selectively engaging the first synchronizer S1 and the brake B5, or the second synchronizer S2 and the brake B6, to provide an engine-motor coupling transmission with different gear ratios between the engine (1) and the motor (4) and the second output shaft (9); Engaging the first clutch CL1, the second clutch CL2, the seventh clutch CL7, the brake B1 and the brake B3, and selectively engaging the first synchronizer S1 and the brake B5, or the second synchronizer S2 and the brake B6, to provide an engine-motor coupling transmission with different gear ratios between the engine (1) and the motor (4) and the first output shaft (8) and the second output shaft (9); The first clutch CL1, the second clutch CL2, the sixth clutch CL6, the brake B1 and the brake B4 are engaged, and the first synchronizer S1 and the brake B5, or the second synchronizer S2 and the brake B6 are selectively engaged to provide an engine and motor coupling transmission with different gear ratios between the engine (1) and the motor (4) and the first output shaft (8).

8. The hydraulic-mechanical compound transmission system of a hybrid tractor according to claim 3, characterized in that: Providing charging transmission between the engine (1) and the motor (4) by selectively engaging the first clutch CL1, the fourth clutch CL4 and the brake B2; By selectively engaging the second clutch CL2, the brake B3 and the brake B7, a braking energy recovery transmission is provided between the second output shaft (9) and the motor (4).

9. A control method for a hydraulic-mechanical compound transmission system of a hybrid tractor according to any one of claims 1 to 8, characterized in that: The steps include: The vehicle controller (2) collects the battery SOC, required torque T req , Braking torque T bre , vehicle speed v, a direction change signal of a transmission controller and a gear shift signal of a transmission controller; When v=0, it is in parking state. If the total output shaft torque T out >0, the vehicle controller (2) controls the first output shaft (8) to output power; if the total output shaft torque T out ≤0, and SOC≤SOC min When the vehicle controller (2) controls the engine (1) and the motor (4) to form a charging transmission; SOC min is the minimum battery state of charge; When v>0, it is in the running state. If SOC max ≤SOC, and the maximum torque of the motor Tmotmax>T req When the SOC (2) controls the motor (4) and the first output shaft (8) or / and the second output shaft (9) to form a motor-driven mechanical transmission; if max ≤SOC, and the maximum torque of the motor Tmotmax≤T req When the SOC is on, the vehicle controller (2) controls the engine (1) and the motor (4) to form an engine-motor coupling transmission with the first output shaft (8) and / or the second output shaft (9); max >SOC, and braking torque T bre >0, the vehicle controller (2) controls the second output shaft (9) and the motor (4) to form a braking energy recovery transmission; if SOC max >SOC, and braking torque T bre <0, and T req ≤ the optimal engine torque TICE_best, the vehicle controller (2) controls the tractor to stop, and the vehicle controller (2) controls the engine (1) and the motor (4) to form a charging transmission; if SOC max >SOC, and braking torque T bre <0, and T req >Engine optimal torque TICE_best, and SOC min >SOC, the vehicle controller (2) controls the engine (1) and the first output shaft (8) or / and the second output shaft (9) to form an engine-only drive; When v>0, when the vehicle controller receives a reversing signal from the transmission controller or a shifting signal from the transmission controller, the vehicle controller (2) controls the engine (1) and the first output shaft (8) or / and the second output shaft (9) to form a hydraulic transmission; if the vehicle controller does not receive a reversing signal from the transmission controller or a shifting signal from the transmission controller, then if T req ≤ the first set value, the vehicle controller (2) controls the engine (1) and the first output shaft (8) and / or the second output shaft (9) to form a hydraulic transmission; if the second set value > T req >When the first setting value is reached, the vehicle controller (2) controls the engine (1) and the first output shaft (8) or / and the second output shaft (9) to form an engine and hydraulic compound transmission; if T req >When the second set value is reached, the vehicle controller (2) controls the engine (1) and the first output shaft (8) and / or the second output shaft (9) to form an engine-driven mechanical transmission.

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