Middle gearbox

Abstract

The utility model belongs to the technical field of tractors, and particularly relates to a middle gearbox which comprises a box body, an input rotating shaft, a front output rotating shaft and a rear output rotating shaft, one end of the input rotating shaft is in transmission connection with the output end of an external constant displacement motor, and the input rotating shaft is in transmission fit with a middle transmission shaft through a gear assembly. The middle transmission shaft is fixedly sleeved with a normally-meshed driving gear, the front output rotating shaft is fixedly sleeved with a normally-meshed driven gear, the front output rotating shaft and the rear output rotating shaft are in transmission connection through a four-wheel-drive gear-shifting meshing sleeve or a synchronizer, and the front output rotating shaft and the rear output rotating shaft are used for being in transmission connection with a front axle mechanism and a rear axle mechanism respectively. The constant displacement motor is adopted as a power source to be matched with the variable pump installed on the engine, so that the hydraulic stepless speed change transmission capacity is achieved, meanwhile, the front output rotating shaft and the rear output rotating shaft can synchronously rotate or be separated in a transmission mode according to actual operation working conditions, and conversion between four-wheel drive and front-wheel drive is achieved. And the power requirements of most working conditions are met.

Description

Technical fields:

[0001] This utility model belongs to the field of tractor technology, and specifically refers to a mid-mounted gearbox. Background technology:

[0002] Most existing tractor transmissions are front-wheel drive, transmitting power from the diesel engine to the front axle via a drivetrain connection to the diesel engine's output. However, in actual operation, various working conditions and road conditions exist, and relying solely on the front-wheel drive locomotive to pull the entire vehicle forward clearly results in insufficient driving capability and poor maneuverability. Furthermore, the diesel engine transmission mechanism also suffers from complex shifting operations and low shifting efficiency. Summary of the Invention:

[0003] The purpose of this utility model is to provide a mid-mounted gearbox, which uses a fixed-displacement motor as a power source and is paired with a variable pump installed on the engine to have hydraulic continuously variable transmission capability. It can also make the front output shaft and the rear output shaft rotate synchronously or be separated according to the actual working conditions to realize the conversion between four-wheel drive and front-wheel drive.

[0004] This utility model is implemented as follows:

[0005] A mid-mounted gearbox includes a housing and an input shaft, a front output shaft, and a rear output shaft rotatably connected within the housing. One end of the input shaft is connected to the output end of an external fixed-displacement motor. The input shaft and an intermediate drive shaft rotating within the housing are driven by a gear assembly. A constant-mesh drive gear is fixedly mounted on the intermediate drive shaft, and a constant-mesh driven gear that meshes with the constant-mesh drive gear is fixedly mounted on the front output shaft. The inner ends of the front output shaft and the rear output shaft are connected by a four-wheel drive shift clutch, a four-wheel drive shift sleeve, or a synchronizer. The outer ends of the front and rear output shafts extend outside the housing and are respectively used for drive connections with the front axle mechanism and the rear axle mechanism.

[0006] In the aforementioned mid-drive gearbox, the gear assembly includes a first-speed drive gear, a second-speed drive gear, and a third-speed drive gear fixedly mounted on the input shaft. A first-speed driven gear meshing with the first-speed drive gear, a second-speed driven gear meshing with the second-speed drive gear, and a third-speed driven gear meshing with the third-speed drive gear are rotatably mounted on the intermediate drive shaft. A first-speed engagement sleeve or synchronizer and a second- and third-speed engagement sleeve or synchronizer are fixedly mounted on the intermediate drive shaft. The first-speed driven gear engages with the first-speed engagement sleeve or synchronizer to achieve synchronous rotation between the first-speed driven gear and the intermediate drive shaft. The second-speed or third-speed driven gear engages with the second- and third-speed engagement sleeve or synchronizer to achieve synchronous rotation between the second-speed or third-speed driven gear and the intermediate drive shaft.

[0007] In one of the aforementioned mid-mounted transmissions, a rear drive brake is provided between the rear output shaft and the gearbox housing.

[0008] In the aforementioned mid-mounted gearbox, the front output shaft and the rear output shaft are coaxially arranged.

[0009] The outstanding advantages of this utility model compared to the prior art are:

[0010] Compared with the prior art, this utility model uses a fixed-displacement motor as a power source and is paired with a variable pump installed on the engine to achieve hydraulic continuously variable transmission capability. This makes the shifting operation simpler and more efficient. At the same time, the front output shaft and the rear output shaft can be rotated synchronously or the transmission can be separated according to the actual working conditions to realize the conversion between four-wheel drive and front-wheel drive, meeting the power requirements of most working conditions. Attached image description:

[0011] Figure 1 This is a simplified diagram of the overall transmission of this utility model.

[0012] In the diagram: 1. Housing; 2. Input shaft; 3. Front output shaft; 4. Rear output shaft; 5. Fixed displacement motor; 6. Intermediate drive shaft; 7. Constant mesh drive gear; 8. Constant mesh driven gear; 9. Four-wheel drive shift sleeve or synchronizer; 10. First gear drive gear; 11. Second gear drive gear; 12. Third gear drive gear; 13. First gear driven gear; 14. Second gear driven gear; 15. Third gear driven gear; 16. First gear shift sleeve or synchronizer; 17. Second and third gear shift sleeve or synchronizer; 18. Rear drive brake. Detailed implementation method:

[0013] The present invention will be further described below with reference to specific embodiments. See also: Figure 1 :

[0014] A mid-mounted gearbox includes a housing 1, and an input shaft 2, a front output shaft 3, and a rear output shaft 4 rotatably connected within the housing 1. One end of the input shaft 2 is connected to the output end of an external fixed-displacement motor 5. The input shaft 2 is connected to an intermediate drive shaft 6 rotating within the housing 1 via a gear assembly. A constant-mesh drive gear 7 is fixedly mounted on the intermediate drive shaft 6. A constant-mesh driven gear 8 that meshes with the constant-mesh drive gear 7 is fixedly mounted on the front output shaft 3. The inner end of the front output shaft 3 and the inner end of the rear output shaft 4 are connected via a four-wheel drive shift clutch, a four-wheel drive shift engagement sleeve, or a synchronizer 9. The outer ends of the front output shaft 3 and the rear output shaft 4 extend outside the housing 1 and are respectively used for transmission connections with the front axle mechanism and the rear axle mechanism.

[0015] Compared with the prior art, this utility model uses a fixed-displacement motor 5 as a power source and is paired with a variable pump installed on the engine to achieve hydraulic stepless speed change transmission capability. This makes the shifting operation simpler and more efficient. At the same time, the front output shaft 3 and the rear output shaft 4 can be rotated synchronously or separated according to the actual working conditions to realize the conversion between four-wheel drive and front-wheel drive, meeting the power requirements of most working conditions.

[0016] Furthermore, the gearbox assembly can be configured with multiple gears according to the actual transmission requirements of the gearbox. In this embodiment, the gearbox assembly includes a first-gear drive gear 10, a second-gear drive gear 11, and a third-gear drive gear 12 fixedly mounted on the input shaft 2. A first-gear driven gear 13 meshing with the first-gear drive gear 10, a second-gear driven gear 14 meshing with the second-gear drive gear 11, and a third-gear driven gear 15 meshing with the third-gear drive gear 12 are rotatably mounted on the intermediate transmission shaft 6. A first-gear engagement sleeve or synchronizer 16 and a second- and third-gear engagement sleeve or synchronizer 17 are fixedly fitted on the intermediate drive shaft 6. The first-gear driven gear 13 engages with the first-gear engagement sleeve or synchronizer 16 to achieve synchronous rotation between the first-gear driven gear 13 and the intermediate drive shaft 6. The second-gear driven gear 14 or the third-gear driven gear 15 engages with the second- and third-gear engagement sleeve or synchronizer 17 to achieve synchronous rotation between the second-gear driven gear 14 or the third-gear driven gear 15 and the intermediate drive shaft 6. That is, the gear assembly in this embodiment has three transmission gears.

[0017] Furthermore, a rear drive brake 18 is provided between the rear output shaft 4 and the housing 1.

[0018] Furthermore, in this embodiment, the front output shaft 3 and the rear output shaft 4 are coaxially arranged. Of course, the front output shaft 3 and the rear output shaft 4 can also be axially parallel, and the two are connected by a transmission gear set and a wet clutch.

[0019] The above embodiments are only one of the preferred embodiments of this utility model and are not intended to limit the scope of implementation of this utility model. Therefore, all equivalent changes made in accordance with the shape, structure and principle of this utility model should be covered within the protection scope of this utility model.

Claims

1. A mid-mounted transmission, characterized in that: It includes a housing (1), and an input shaft (2), a front output shaft (3), and a rear output shaft (4) rotatably connected within the housing (1). One end of the input shaft (2) is connected to the output end of an external quantitative motor (5). The input shaft (2) is connected to an intermediate transmission shaft (6) rotating within the housing (1) via a gear assembly. A constant mesh drive gear (7) is fixedly mounted on the intermediate transmission shaft (6). A constant mesh driven gear (8) meshing with the constant mesh drive gear (7) is fixedly mounted on the front output shaft (3). The inner end of the front output shaft (3) and the inner end of the rear output shaft (4) are connected via a four-wheel drive shift clutch, a four-wheel drive shift engagement sleeve, or a synchronizer (9). The outer ends of the front output shaft (3) and the rear output shaft (4) extend outside the housing (1) and are respectively used for transmission connection with the front axle mechanism and the rear axle mechanism.

2. A mid-mounted gearbox according to claim 1, characterized in that: The gear assembly includes a first-gear drive gear (10), a second-gear drive gear (11), and a third-gear drive gear (12) fixedly mounted on the input shaft (2). A first-gear driven gear (13) meshing with the first-gear drive gear (10), a second-gear driven gear (14) meshing with the second-gear drive gear (11), and a third-gear driven gear (15) meshing with the third-gear drive gear (12) are rotatably mounted on the intermediate transmission shaft (6). The intermediate transmission shaft (6) is fixedly mounted with… The first gear engagement sleeve or synchronizer (16) is engaged with the second and third gear engagement sleeves or synchronizers (17), and the first gear driven gear (13) is engaged with the first gear engagement sleeve or synchronizer (16) to achieve synchronous rotation of the first gear driven gear (13) and the intermediate transmission shaft (6). The second gear driven gear (14) or the third gear driven gear (15) is engaged with the second and third gear engagement sleeves or synchronizers (17) to achieve synchronous rotation of the second gear driven gear (14) or the third gear driven gear (15) and the intermediate transmission shaft (6).

3. A mid-mounted gearbox according to claim 1, characterized in that: A rear drive brake (18) is provided between the rear output shaft (4) and the housing (1).

4. A mid-mounted gearbox according to claim 1, characterized in that: The front output shaft (3) and the rear output shaft (4) are coaxial.

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