High-torque tractor CVT power assembly

Abstract

The utility model relates to the technical field of tractor power assemblies, in particular to a high-torque tractor CVT power assembly. Comprising an engine, a generator, a driving motor and a gearbox, the output end of the engine is in transmission connection with a driving shaft, the end, away from the engine, of the driving shaft is coaxially in transmission connection with a PTO shaft, and the driving shaft is in transmission connection with a generator rotor; an output shaft is arranged on the driving motor, an input shaft is arranged on the gearbox, and the output shaft and the input shaft are in speed reduction transmission connection through a transmission mechanism. By means of the structure, the torque output by the input shaft into the gearbox is larger, the maximum torque capable of being output by the whole power assembly is improved, the power assembly can better meet the requirement for the large torque when a tractor starts or climbs a slope, the load of a driving motor when the tractor starts or climbs the slope is reduced, and therefore the tractor can be driven to run stably. The possibility of burning of the driving motor is reduced, and the service life of the driving motor is prolonged.

Description

Technical Field

[0001] This utility model relates to the field of tractor powertrain technology, specifically to a high-torque tractor CVT powertrain. Background Technology

[0002] Traditional tractors mostly use manual shifting systems. When tractors are working in the field, they often need to stop frequently to shift gears to meet the requirements of implement operation and traction. This results in low work efficiency and unstable work quality. At the same time, the engine speed is directly related to the vehicle speed. Changes in the overall vehicle speed cause large fluctuations in engine speed. The engine cannot operate within a stable speed range, resulting in high fuel consumption, poor emissions, and significant vibration and wear.

[0003] With the rapid development of the new energy vehicle industry, tractor R&D personnel, adhering to the principles of high efficiency and energy saving, have developed a hybrid tractor CVT powertrain. This system uses a drive motor to propel the tractor, allowing direct control of forward and reverse movement by controlling the drive motor's rotation, and controlling the tractor's speed by controlling the speed of the drive motor's output shaft. This makes the tractor's powertrain more stable and fuel-efficient. While drive motors in tractors are often only used for forward and reverse movement, in agricultural production, tractors often need to drive other agricultural implements. The power source for these implements usually still comes from the tractor's engine, with the engine's output connected to the PTO shaft. The PTO shaft, through the PTO mechanism, transmits the engine's power to the implements, thus enabling the implements to operate.

[0004] In summary, the existing CVT powertrain for tractors mainly includes an engine, a drive motor, and a gearbox. The engine can drive the PTO shaft to rotate through the drive shaft, thereby transmitting power to the PTO mechanism to drive the agricultural implements to work. The output shaft of the drive motor is often directly and coaxially fixedly connected to the input shaft of the gearbox, so that the drive motor can transmit power to the rear axle through the gearbox, ultimately controlling the movement of the rear wheels.

[0005] Because tractors have a large self-weight and often need to tow agricultural implements, they require a large torque when starting or going uphill. In the current technology, the direct connection between the output shaft of the drive motor and the input shaft of the gearbox often cannot meet the high torque requirements of the tractor, resulting in excessive load on the drive motor when starting or going uphill, which reduces the service life of the drive motor. Utility Model Content

[0006] To address the aforementioned problems, this utility model provides a high-torque tractor CVT powertrain to solve the problem that the direct connection between the drive motor output shaft and the gearbox input shaft in the prior art leads to excessive load on the drive motor when going uphill or starting, resulting in a shorter service life of the drive motor.

[0007] This utility model is achieved using the following technical solution: a high-torque tractor CVT powertrain, including an engine, a generator, a drive motor and a gearbox, wherein the output end of the engine is driven by a drive shaft, and the end of the drive shaft away from the engine is coaxially driven by a PTO shaft, and the drive shaft is driven by the generator rotor; the drive motor is provided with an output shaft, the gearbox is provided with an input shaft, and the output shaft and the input shaft are connected by a transmission mechanism for speed reduction.

[0008] The above structure allows for a greater output torque in the input shaft gearbox, thereby increasing the maximum torque that the entire powertrain can output. This enables the powertrain in the utility model to better meet the high torque requirements of the tractor when starting or going uphill, reducing the load on the drive motor when starting or going uphill, reducing the possibility of drive motor burnout, and increasing the service life of the drive motor.

[0009] Preferably, the input shaft and output shaft are coaxial, and the transmission mechanism is a planetary reduction gear set. This coaxial reduction transmission method makes the power transmission from the output shaft to the input shaft more stable.

[0010] Preferably, the planetary reduction gear set includes a ring gear, a sun gear fixedly connected coaxially to the output shaft at the center of the ring gear, and several planet gears meshing with the sun gear and the ring gear between the sun gear and the ring gear. A planet carrier is mounted on each of the planet gears and is fixedly connected coaxially to the input shaft. By configuring the planetary reduction gear set, a high reduction ratio, high torque transmission, and high dynamic stability are achieved with minimal space.

[0011] Preferably, both the input shaft and the output shaft are hollow shafts. The end of the PTO shaft furthest from the engine passes sequentially through the input shaft, the planetary reduction gear set, the output shaft, and the gearbox, extending to the outside of the gearbox. The hollow design of the input and output shafts allows the PTO shaft to pass through both, saving space during installation. Furthermore, the coaxial arrangement of the drive shaft, PTO shaft, input shaft, and output shaft ensures more stable power transmission.

[0012] Preferably, the input shaft and output shaft are parallel, and the transmission mechanism includes a first gear coaxially and fixedly connected to the output shaft, and a second gear coaxially and fixedly connected to the input shaft, meshing with the first gear. The number of teeth on the second gear is greater than the number of teeth on the first gear. The speed reduction transmission is achieved through the meshing of the first and second gears, simplifying the transmission mechanism's structure, facilitating standardized production, and reducing costs. Furthermore, the parallel arrangement of the input and output shafts allows for more diverse installation positions for the drive motor and effectively reduces the installation space required in the tractor's longitudinal direction, making it more suitable for small tractors with limited longitudinal length.

[0013] Preferably, the drive shaft, PTO shaft, and input shaft are coaxial, with the input shaft being a hollow shaft. The end of the PTO shaft furthest from the engine passes through the input shaft and the gearbox, extending to the outside of the gearbox. By making the input shaft hollow, the PTO shaft can be installed by passing it through the input shaft and the gearbox, thus saving space during installation.

[0014] Preferably, the end of the drive shaft furthest from the engine is provided with a spline sleeve with internal splines, and the end of the PTO shaft near the engine is provided with an external spline that matches the internal spline of the spline sleeve. The end of the PTO shaft near the engine is inserted into the spline sleeve. The transmission connection is achieved by the cooperation of external and internal splines, which realizes the balance between power transmission and axial degree of freedom. Its core value lies in adapting to dynamic working conditions, improving reliability, and simplifying maintenance.

[0015] Preferably, the output end of the engine is connected to a flywheel, which is driven by a clutch and engages with the drive shaft. Through the arrangement of the flywheel and clutch, they work together to achieve smooth power output, vibration suppression, and power on / off control, making the entire powertrain more efficient and stable.

[0016] Preferably, the drive shaft is coaxially and fixedly connected to the generator rotor. This coaxial connection allows the engine to directly power the generator via the drive shaft, making the device more energy-efficient.

[0017] In summary, the beneficial effects of this utility model are as follows: By employing a planetary reduction gear set or a large and small gear set for speed reduction transmission, the maximum torque input to the gearbox input shaft can be increased, thereby enabling the gearbox to output a larger maximum torque. This overcomes the limitations of existing gearboxes, allowing the powertrain in this device to better handle situations such as tractors going uphill or starting, reducing the load on the drive motor, and increasing its service life. Furthermore, the drive motor often operates at a high speed during startup; the speed reduction through the transmission mechanism effectively lowers the input speed of the input shaft into the gearbox, reducing the occurrence of gear grinding caused by excessive speed and decreasing frictional losses. This further improves the stability of power transmission in this device and increases the service life of the gearbox. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of this utility model;

[0019] Figure 2 This is a schematic diagram of the structure of Embodiment 2 of this utility model.

[0020] In the diagram: 1-Engine; 2-Flywheel; 3-Clutch; 4-Generator; 5-Drive shaft; 6-PTO shaft; 7-Drive motor; 8-Output shaft; 9-First gear; 10-Second gear; 11-Input shaft; 12-Gearbox; 13-Rear axle; 14-Planetary reduction gear set; 15-Ring gear; 16-Planet gear; 17-Planet carrier; 18-Sun gear. Detailed Implementation

[0021] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.

[0022] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0023] The following is a description of preferred embodiments of the present invention in conjunction with the accompanying drawings. Example 1:

[0024] like Figure 1As shown, this utility model provides a high-torque CVT powertrain for a tractor, including an engine 1, a generator 4, a drive motor 7, and a gearbox 12. The output end of the engine 1 is connected to a drive shaft 5. Specifically, the output end of the engine 1 is connected to a flywheel 2, which is engaged with the drive shaft 5 via a clutch 3. The clutch 3 controls the engagement or disengagement of power between the flywheel 2 and the drive shaft 5. A PTO shaft 6 is coaxially connected to the end of the drive shaft 5 furthest from the engine 1. The drive shaft 5 is coaxially and fixedly connected to the rotor of the generator 4. The drive motor 7 has an output shaft 8, and the gearbox 12 has an input shaft 11. The output shaft 8 and the input shaft 11 are connected by a transmission mechanism for speed reduction.

[0025] The transmission connection between the drive shaft 5 and the PTO shaft 6 is mainly achieved through a spline fit. Specifically, the end of the drive shaft 5 furthest from the engine 1 has a spline sleeve with internal splines, and the end of the PTO shaft 6 closest to the engine 1 has an external spline that matches the internal spline of the spline sleeve. The end of the PTO shaft 6 closest to the engine 1 is inserted into the spline sleeve. During operation, the engine 1 and the PTO mechanism may experience slight axial displacement due to vibration or installation tolerances. The longitudinal sliding characteristics of the spline allow the shaft to freely expand and contract while transmitting torque, avoiding stress concentration or deformation caused by rigid fixing. At the same time, the spline connection can accommodate a certain degree of installation deviation, making installation relatively convenient.

[0026] In this embodiment, the transmission mechanism is a planetary reduction gear set 14. At this time, the input shaft 11 and the output shaft 8 are coaxial, that is, their axes are collinear. The planetary reduction gear set 14 includes a ring gear 15. A sun gear 18 is provided in the middle of the ring gear 15 and is coaxially and fixedly connected to the output shaft 8. A plurality of planet gears 16 are provided between the sun gear 18 and the ring gear 15, and a planet carrier 17 is mounted on the plurality of planet gears 16. The planet carrier 17 is coaxially and fixedly connected to the input shaft 11.

[0027] To further save installation space, the input shaft 11 and output shaft 8 are designed as hollow shafts. The PTO shaft 6 passes through the input shaft 11, output shaft 8, and gearbox 12, with the end of the PTO shaft 6 furthest from the engine 1 located on the outside of the gearbox 12. This results in a smaller installation space and a more compact structure.

[0028] When the tractor needs to drive agricultural implements, engine 1 starts. Engine 1 drives PTO shaft 6 to rotate via drive shaft 5, thereby transmitting power to the PTO mechanism to control the operation of the agricultural implements. Simultaneously, the rotor of generator 4 rotates synchronously, generating electrical energy. This energy is stored in the energy storage unit and can be used by drive motor 7 when needed. The energy storage unit can also be charged and stored independently; this is conventional technology and will not be elaborated upon here. When the tractor needs to move, drive motor 7 is started. The power output from drive motor 7's output shaft 8 first passes through planetary reduction gear set 14 for speed reduction and torque increase, resulting in a larger maximum torque output from gearbox 12. Gearbox 12 then transmits power to the rear axle 13, driving the wheels. The larger torque output facilitates tractor starting or subsequent uphill driving. Once the tractor is running smoothly, the power output of the powertrain can be controlled by adjusting gearbox 12. Example 2:

[0029] like Figure 2 As shown, the structure of this embodiment is basically the same as that of Embodiment 1. The difference is that in this embodiment, the input shaft 11 and the output shaft 8 are parallel. The transmission mechanism includes a first gear 9 that is coaxially fixedly connected to the output shaft 8. A second gear 10 that meshes with the first gear 9 is coaxially fixedly connected to the input shaft 11. The number of teeth of the second gear 10 is greater than the number of teeth of the first gear 9.

[0030] In this embodiment, the drive shaft 5, PTO shaft 6, and input shaft 11 are coaxial. The input shaft 11 is a hollow shaft. The PTO shaft 6 passes through the input shaft 11 and the gearbox 12. The end of the PTO shaft 6 away from the engine 1 is located on the outside of the gearbox 12.

[0031] The first gear 9 and the second gear 10 also serve to reduce speed and increase torque. Compared with the planetary reduction gear set 14 in Embodiment 1, the structure of this embodiment is simpler and the cost is lower. The planetary reduction gear set 14 in Embodiment 1 has a complex structure and a higher cost, but its speed reduction and torque increase effect is better.

[0032] Furthermore, in both Embodiment 1 and Embodiment 2, the PTO shaft 6 passes through the shaft and gearbox 12 but does not interact with them.

[0033] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present utility model, and these improvements and substitutions should also be considered within the protection scope of the present utility model.

Claims

1. A high torque tractor CVT power assembly comprising an engine (1), a generator (4), a drive motor (7) and a gearbox (12), the output end of the engine (1) being drivingly connected to a drive shaft (5), characterised in that, The drive shaft (5) is coaxially connected to the PTO shaft (6) at the end away from the engine (1), and the drive shaft (5) is connected to the rotor of the generator (4) through a transmission mechanism; the drive motor (7) is provided with an output shaft (8), and the gearbox (12) is provided with an input shaft (11). The output shaft (8) and the input shaft (11) are connected through a transmission mechanism for speed reduction.

2. The high torque tractor CVT powertrain of claim 1, wherein, The input shaft (11) is coaxial with the output shaft (8), and the transmission mechanism is a planetary reduction gear set (14).

3. The high torque tractor CVT powertrain of claim 2, wherein, The planetary reduction gear set (14) includes a gear ring (15), a sun gear (18) is provided in the middle of the gear ring (15) and is fixedly connected to the output shaft (8) on the same axis, and a number of planet gears (16) are provided between the sun gear (18) and the gear ring (15) to mesh with the sun gear (18) and the gear ring (15). A planet carrier (17) is installed on the number of planet gears (16), and the planet carrier (17) is fixedly connected to the input shaft (11) on the same axis.

4. The high-torque tractor CVT powertrain according to claim 3, characterized in that, Both the input shaft (11) and the output shaft (8) are hollow shafts. The end of the PTO shaft (6) away from the engine (1) passes through the input shaft (11), the planetary reduction gear set (14), the output shaft (8), the gearbox (12), and extends to the outside of the gearbox (12).

5. The high torque tractor CVT powertrain of claim 1, wherein, The input shaft (11) is parallel to the output shaft (8). The transmission mechanism includes a first gear (9) that is coaxially fixedly connected to the output shaft (8). A second gear (10) that meshes with the first gear (9) is coaxially fixedly connected to the input shaft (11). The number of teeth of the second gear (10) is greater than the number of teeth of the first gear (9).

6. The high torque tractor CVT powertrain of claim 5, wherein, The drive shaft (5), PTO shaft (6), and input shaft (11) are coaxial. The input shaft (11) is a hollow shaft. The end of the PTO shaft (6) away from the engine (1) passes through the input shaft (11), the gearbox (12), and extends to the outside of the gearbox (12).

7. The high torque tractor CVT powertrain of claim 1, wherein, The drive shaft (5) is provided with a spline sleeve with an inner spline at the end away from the engine (1), and the PTO shaft (6) is provided with an outer spline that matches the inner spline of the spline sleeve at the end near the engine (1). The end of the PTO shaft (6) near the engine (1) is inserted into the spline sleeve.

8. The high torque tractor CVT powertrain of claim 1, wherein, The output end of the engine (1) is connected to a flywheel (2), and the flywheel (2) is driven by the drive shaft (5) through a clutch (3).

9. The high torque tractor CVT powertrain of claim 1, wherein, The drive shaft (5) is coaxially and fixedly connected to the rotor of the generator (4).

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