Full-time four-wheel drive transfer case and method

Abstract

The application relates to a full-time full-gear transmission four-wheel drive transfer and method, and belongs to the technical field of automobile transfer. A technical scheme: an input shaft of a planetary gear mechanism is connected with a main shaft; the main shaft is connected with a central differential; the central differential distributes power to a driving gear and a differential rear output gear through planetary bevel gears; the driving gear and the differential rear output gear rotate at different speeds on the main shaft; the differential rear output gear is connected with a rear output shaft; the end of the rear output shaft is connected with a rear output flange; the driving gear is engaged with an intermediate shaft gear; the intermediate shaft gear is engaged with a front output gear; and the front output gear is connected with a front output flange. The transfer has small volume and light weight; multiple planetary gears simultaneously share loads and power is split; the same volume has higher rated torque and higher short-time overload capacity; the central differential is equipped to compensate for the speed difference between front and rear wheels during vehicle turning and to avoid damage of the transmission system caused by tooth locking.

Description

Technical Field

[0001] This invention relates to a full-time, all-gear transmission four-wheel drive transfer case and method, belonging to the field of automotive transfer case technology. Background Technology

[0002] The transfer case is a crucial component of four-wheel drive vehicles. It reduces vehicle speed, increases output torque, and improves off-road capability by traversing soft, bumpy, and ditch-prone surfaces. Currently, user demand for all-weather, all-terrain four-wheel drive safety is continuously increasing. Existing part-time four-wheel drive transfer cases have the drawback of prohibiting four-wheel drive engagement on paved roads, requiring only two-wheel drive for daily driving. In sudden situations such as slippery conditions or rain and snow, four-wheel drive cannot engage promptly. Furthermore, the transfer case uses a chain to transmit power to the front output shaft, resulting in significant noise, and prolonged use can lead to chain stretching and tooth skipping under heavy loads.

[0003] Chinese patent application CN2020208734305 discloses a full-time four-wheel drive transfer case structure. The technical solution is as follows: the high and low gear shift forks include two shift forks hinged together: one shift fork engages with the high-speed gear sleeve, and the other shift fork engages with the low-speed gear sleeve, enabling constant four-wheel drive even on paved roads. However, this patent application has a problem: during gear shifting, one shift fork controls the movement of two gear sleeves, resulting in high shifting force. If shifting manually, the driver will find it difficult to shift gears; if the motor shifts, the motor current will be higher than normal, making it more prone to overheating and even burnout. Furthermore, when the vehicle requires high torque output, the transfer case is in low gear. Power is transmitted from the input flange to the input shaft. The gear ring on the input shaft meshes with the gear on the intermediate shaft, completing the power transmission from the input shaft to the intermediate shaft. The internal splines of the low-speed gear sleeve engage with the external splines of the intermediate shaft and the external splines of the low-speed wandering gear, transmitting power to the low-speed wandering gear. The gears of the low-speed wandering gear mesh with the low-speed driven gear, transmitting power to the low-speed driven gear. The reduction mechanism in this patent application is a traditional two-stage reducer mechanism. The transfer case has large dimensions, with the load concentrated on a few gear teeth, resulting in weak overload and impact resistance. Summary of the Invention

[0004] This invention proposes a full-time, all-gear transmission four-wheel drive transfer case and method. The transfer case is small in size and light in weight; multiple planetary gears share the load simultaneously, power is distributed, and the rated torque and short-term overload capacity are higher for the same volume; it avoids the problems of chain elongation and tooth skipping in traditional chain drives; it is equipped with a central differential to compensate for the speed difference between the front and rear wheels when the vehicle is turning, avoids gear damage in the transmission system, improves the ability to pass through desert, mud or deep snow conditions, and solves the above-mentioned technical problems existing in the prior art.

[0005] The technical solution of this invention is: A full-time, all-gear transmission four-wheel drive transfer case includes a main shaft and a planetary gear mechanism, the input shaft of which is connected to the main shaft. The main shaft is equipped with a drive gear, a central differential, and a rear output gear, with the central differential located between the drive gear and the rear output gear. The main shaft is connected to the central differential, which distributes power to the drive gear and the rear output gear via its planetary bevel gears. The drive gear and the rear output gear rotate differentially on the main shaft. The rear output gear is connected to a rear output shaft, the end of which is connected to... The rear output flange is connected; the drive gear meshes with the intermediate gear, and the intermediate gear meshes with the front output gear. The drive gear, intermediate gear, and front output gear are arranged in parallel from top to bottom. The shaft where the front output gear is located is connected to the front output flange. Power is transmitted sequentially from the input shaft and main shaft of the planetary gear mechanism to the central differential, where it is divided into two paths. One path is transmitted to the front output flange via the drive gear, intermediate gear, and front output gear; the other path is transmitted to the rear output flange via the differential's rear output gear and rear output shaft. The entire power transmission process is completed through gear meshing.

[0006] Furthermore, a four-wheel drive locking gear hub is provided on the main shaft. The internal spline of the four-wheel drive locking gear hub is connected to the external spline of the main shaft, and the external spline of the four-wheel drive locking gear hub is connected to the internal spline of the four-wheel drive locking gear sleeve. The four-wheel drive locking gear hub and the four-wheel drive locking gear sleeve are arranged near the left side of the drive gear. After the four-wheel drive locking gear sleeve slides to the right, the right side of the internal spline of the four-wheel drive locking gear sleeve is connected to the external spline of the drive gear, and the left side of the internal spline of the four-wheel drive locking gear sleeve is connected to the external spline of the four-wheel drive locking gear hub.

[0007] Furthermore, the input shaft and main shaft of the planetary gear mechanism are connected by a high-low gear sleeve. The internal spline of the high-low gear sleeve is connected to the external spline of the main shaft, and the external spline of the high-low gear sleeve is connected to the internal spline of the input shaft or the internal spline of the planet carrier of the planetary gear mechanism. When the external spline of the high-low gear sleeve is connected to the internal spline of the input shaft, the rotational speed of the high-low gear sleeve is the same as the rotational speed of the input shaft. When the high-low gear sleeve slides to the right on the main shaft and the external spline of the high-low gear sleeve is connected to the internal spline of the planet carrier, the rotational speed of the high-low gear sleeve is the same as the rotational speed of the planet carrier.

[0008] Furthermore, the external spline of the spindle is connected to the internal spline of the central differential.

[0009] Furthermore, a needle roller bearing is press-fitted into the inner bore of the drive gear; and a bushing is press-fitted into the inner bore of the differential's rear output gear.

[0010] Furthermore, the shaft containing the front output gear is connected to the front output flange via a spline, the rear output gear of the differential is connected to the rear output shaft via a spline, and the rear output flange is connected to the rear output shaft via a spline.

[0011] Furthermore, the planetary gear mechanism includes an input shaft, a planet carrier baffle, a planet carrier, planet gears, and a planet gear shaft. The planet carrier baffle, planet gear shaft, and planet gears are all mounted on the planet carrier. The input shaft meshes with the planet gears via gears, and the planet gears are mounted on the planet carrier via the planet gear shaft. The planet carrier baffle is fixed to the left side of the planet gears via the planet gear shaft. An annular step is provided on the input shaft, and the planet carrier baffle is located on the annular step to block the input shaft, thus providing axial limiting. The tapered surface on the left side of the planet gear shaft matches the chamfer of the through hole on the planet carrier baffle to form a limiting function. The right end of the planet gear shaft is a hollow structure, and the outer edge of the right end is riveted to fit against the right end face of the planet carrier.

[0012] Furthermore, the input shaft, main shaft, drive gear, central differential, differential rear output gear, rear output shaft, and rear output flange are located on the same axis.

[0013] A method for using a full-time, all-gear transmission four-wheel drive transfer case, including three modes: Mode A is for daily driving of four-wheel drive vehicles, in 4H four-wheel drive mode. The central differential distributes power to the drive gear and the rear output gear of the differential through planetary bevel gears. The drive gear transmits power to the front output flange, and the rear output gear of the differential transmits power to the rear output flange. When the vehicle turns, the front and rear wheels rotate at different speeds, causing the rear output flange and the front output flange to rotate at different speeds. Under the action of the central differential, the drive gear and the rear output gear of the differential form a speed difference to avoid gear damage. Mode B improves passability. When the driver switches to the 4HL four-wheel drive lock position, the four-wheel drive lock sleeve slides to the right. The right side of the inner spline of the four-wheel drive lock sleeve connects to the outer spline of the drive gear, and the left side of the inner spline of the four-wheel drive lock sleeve connects to the outer spline of the four-wheel drive lock hub. The inner spline of the four-wheel drive lock hub connects to the outer spline of the main shaft. That is, after switching to the 4HL four-wheel drive lock position, the drive gear is connected to the main shaft, the central differential no longer acts as a differential, the drive gear is connected to the rear output gear of the differential, and the power is transmitted to the rear output flange and the front output flange in a 50:50 ratio, improving the passability of the four-wheel drive vehicle. Mode C is for vehicle extrication. The high and low gear sleeve slides to the right on the main shaft via the shift fork. The high and low gear sleeve connects to the planetary carrier. At this time, the rotation speed of the high and low gear sleeve is the same as that of the planetary carrier. According to the planetary structure reduction ratio, the speed is reduced and the torque is increased. Finally, the increased torque is transmitted to the rear output flange and the front output flange to provide maximum power and traction for off-road extrication of four-wheel drive vehicles.

[0014] The positive effects of this invention are as follows: A planetary gear mechanism is used to achieve deceleration and torque increase, resulting in a smaller and lighter transfer case; multiple planetary gears simultaneously share the load, power is distributed, and the rated torque and short-term overload capacity are higher for the same volume; all-gear transmission distributes power between the front and rear axles, avoiding the chain elongation and tooth skipping problems of traditional chain transmissions; a central differential is equipped to compensate for the speed difference between the front and rear wheels when the vehicle is turning, preventing damage to the transmission system's gears; the transfer case has a four-wheel drive mechanical lock function, which, when locked, achieves a 50:50 power distribution between the front and rear drive shafts, improving the ability to pass through desert, muddy, or deep snow conditions. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a planetary gear mechanism according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the planetary carrier gasket installed in the planetary carrier limiting hole according to an embodiment of the present invention; Figure 3 This is a schematic diagram of a part in an embodiment of the present invention where the transfer case is mounted on the main shaft; Figure 4 This is a schematic diagram of the overall mechanism of the transfer case 4H in four-wheel drive mode according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the overall mechanism of the 4HL transfer case in four-wheel drive lock position according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the overall mechanism of the transfer case 4L four-wheel drive lock in low gear according to an embodiment of the present invention; In the diagram: Input shaft 1, Planetary carrier baffle 2, Planetary carrier 3, Planetary gear 4, Planetary gear shaft 5, High and low gear sleeve 6, Main shaft 7, Four-wheel drive locking hub 8, Four-wheel drive locking sleeve 9, Drive gear 10, Central differential 11, Differential rear output gear 12, Rear output shaft 13, Rear output flange 14, Intermediate gear 15, Front output gear 16, Front output flange 17, Planetary carrier gasket 18, Ball bearing 1 19, Tapered bearing 1 20, Needle roller bearing 21, Adjusting shim 1 22, Adjusting shim 2 23, Bushing 24, Tapered bearing 2 25, Adjusting shim 3 26, Ball bearing 2 27, Ball bearing 3 28, Ball bearing 4 29. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0017] A full-time, all-gear transmission four-wheel drive transfer case includes a main shaft 7 and a planetary gear mechanism. The input shaft 1 of the planetary gear mechanism is connected to the main shaft 7. The main shaft 7 is provided with a drive gear 10, a central differential 11, and a differential rear output gear 12. The central differential 11 is located between the drive gear 10 and the differential rear output gear 12. The main shaft 7 is connected to the central differential 11, and the central differential 11 distributes power to the drive gear 10 and the differential rear output gear 12 through its planetary bevel gears. The drive gear 10 and the differential rear output gear 12 rotate differentially on the main shaft 7. The differential's rear output gear 12 is connected to the rear output shaft 13, and the end of the rear output shaft 13 is connected to the rear output flange 14. The drive gear 10 meshes with the intermediate gear 15, and the intermediate gear 15 meshes with the front output gear 16. The drive gear 10, intermediate gear 15, and front output gear 16 are arranged in parallel from top to bottom, and the shaft containing the front output gear 16 is connected to the front output flange 17. The input shaft 1, main shaft 7, drive gear 10, central differential 11, differential's rear output gear 12, rear output shaft 13, and rear output flange 14 are located on the same axis. Power is transmitted sequentially from the planetary gear mechanism's input shaft 1 and main shaft 7 to the central differential 11, where it is divided into two paths. One path is transmitted through the drive gear 10, intermediate gear 15, and front output gear 16 to the front output flange 17; the other path is transmitted through the differential's rear output gear 12 and rear output shaft 13 to the rear output flange 14. The entire power transmission process is completed through gear meshing.

[0018] The rear output shaft 13 is rigidly connected to the rear output flange 14, that is, the differential rear output gear 12 is rigidly connected to the rear output flange 14. When the four-wheel drive vehicle turns, the front and rear wheels rotate at different speeds, which causes the rear output flange 14 and the front output flange 17 to rotate at different speeds. Under the action of the central differential 11, the drive gear 10 and the differential rear output gear 12 form a speed difference to avoid damage to the transmission system.

[0019] The central differential 11 is a well-known and commonly used mechanism in the art, used to solve the problem of inconsistent speeds between the front and rear wheels, and to avoid difficulty in steering the vehicle or breakage of the drive shaft.

[0020] The main shaft 7 is provided with a four-wheel drive locking gear hub 8. The internal spline of the four-wheel drive locking gear hub 8 is connected to the external spline of the main shaft 7. The external spline of the four-wheel drive locking gear hub 8 is connected to the internal spline of the four-wheel drive locking gear sleeve 9. The four-wheel drive locking gear hub 8 and the four-wheel drive locking gear sleeve 9 are arranged near the left side of the drive gear 10. After the four-wheel drive locking gear sleeve 9 slides to the right, the right side of the internal spline of the four-wheel drive locking gear sleeve 9 is connected to the external spline of the drive gear 10, and the left side of the internal spline of the four-wheel drive locking gear sleeve 9 is connected to the external spline of the four-wheel drive locking gear hub 8.

[0021] The input shaft 1 and main shaft 7 of the planetary gear mechanism are connected by a high-low gear sleeve 6. The internal spline of the high-low gear sleeve 6 is connected to the external spline of the main shaft 7. The external spline of the high-low gear sleeve 6 is connected to the internal spline of the input shaft 1 or the internal spline of the planetary carrier 3 of the planetary gear mechanism. When the external spline of the high-low gear sleeve 6 is connected to the internal spline of the input shaft 1, the rotational speed of the high-low gear sleeve 6 is the same as that of the input shaft 1. When the high-low gear sleeve 6 slides to the right on the main shaft 7 and the external spline of the high-low gear sleeve 6 is connected to the internal spline of the planetary carrier 3, the rotational speed of the high-low gear sleeve 6 is the same as that of the planetary carrier 3. According to the planetary structure reduction ratio, the speed is reduced and the torque is increased. Finally, the increased torque is transmitted to the rear output flange 14 and the front output flange 17 to provide maximum power and traction for off-road extrication of four-wheel drive vehicles.

[0022] A method for using a full-time, all-gear transmission four-wheel drive transfer case, including three modes: Mode A is for daily driving of the four-wheel drive vehicle, in 4H four-wheel drive mode. Input shaft 1 and main shaft 7, and main shaft 7 and central differential 11 are rigidly connected. The central differential 11 distributes power to the drive gear 10 and the differential rear output gear 12 through planetary bevel gears. The drive gear 10 transmits power to the front output flange 17, and the differential rear output gear 12 transmits power to the rear output flange 14. When the vehicle turns, the front and rear wheels rotate at different speeds, causing the rear output flange 14 and the front output flange 17 to rotate at different speeds. Under the action of the central differential 11, the drive gear 10 and the differential rear output gear 12 form a speed difference to avoid gear damage. In Mode B, to improve passability, the driver switches to the 4HL four-wheel drive lock-up position. The four-wheel drive lock-up sleeve 9 slides to the right, and the right side of the inner spline of the four-wheel drive lock-up sleeve 9 is rigidly connected to the outer spline of the drive gear 10. The left side of the inner spline of the four-wheel drive lock-up sleeve 9 is rigidly connected to the outer spline of the four-wheel drive lock-up hub 8. The inner spline of the four-wheel drive lock-up hub 8 is rigidly connected to the outer spline of the main shaft 7. That is, after switching to the 4HL four-wheel drive lock-up position, the drive gear 10 is rigidly connected to the main shaft 7, the central differential 11 no longer plays a differential role, the drive gear 10 is rigidly connected to the differential rear output gear 12, and the power is transmitted to the rear output flange 14 and the front output flange 17 in a 50:50 ratio, realizing a rigid connection between the front and rear drive shafts and improving the passability of the four-wheel drive vehicle in desert, mud or deep snow conditions. Mode C is for vehicle extrication. The high and low gear sleeve 6 slides to the right on the main shaft 7 via the shift fork. The high and low gear sleeve 6 is splinedly connected to the planetary carrier 3. The rotational speed of the high and low gear sleeve 6 is the same as that of the planetary carrier 3. According to the planetary structure reduction ratio, the speed is reduced and the torque is increased. Finally, the increased torque is transmitted to the rear output flange 14 and the front output flange 17 to provide maximum power and traction, which is used for off-road extrication of four-wheel drive vehicles.

[0023] In the embodiments, refer to the appendix. Figure 1 ,2 The planetary gear mechanism includes an input shaft 1, a planetary carrier baffle 2, a planetary carrier 3, planetary gears 4, and a planetary gear shaft 5. The planetary carrier baffle 2, planetary gear shaft 5, and planetary gears 4 are mounted on the planetary carrier 3. The input shaft 1 and planetary gears 4 are meshed by gears. The planetary gear shaft 5 mounts the planetary carrier baffle 2 and planetary gears 4 on the planetary carrier 3. The right side of the planetary carrier baffle 2 blocks the annular step of the input shaft 1, which serves as an axial limit. The tapered surface on the left side of the planetary gear shaft 5 matches the chamfer of the through hole on the planetary carrier baffle 2, forming a limit. The right end of the planetary gear shaft 5 is a hollow structure, and the outer edge of the right end is riveted to fit against the right end face of the planetary carrier 3. A planetary carrier washer 18 is placed between the input shaft 1 and the planetary carrier 3. Two claws protrude from the planetary carrier washer 18 and are installed in the limiting groove of the planetary carrier 3 to ensure that there is no relative movement between the planetary carrier washer 18 and the planetary carrier 3, thereby improving wear resistance.

[0024] See attached document Figure 1 , 2 3 and 4, a full-time all-gear transmission four-wheel drive transfer case, comprising a planetary gear mechanism, ball bearing 19 and bevel bearing 20 mounted on the input shaft 1, high and low gear sleeve 6, four-wheel drive locking hub 8, four-wheel drive locking sleeve 9, drive gear 10, central differential 11, and differential rear output gear 12 mounted on the main shaft 7. Ball bearing 19 is positioned between the input shaft 1 and the housing, and bevel bearing 20 is positioned between the input shaft 1 and the main shaft 7. Two needle roller bearings 21 are press-fitted into the inner bore of the drive gear 10, and bushings 24 are press-fitted into the inner bore of the differential rear output gear 12, allowing differential rotation on the main shaft 7. Both the drive gear 10 and the differential rear output gear 12 are equipped with bevel gears. Adjusting shims 22 and 23 are installed on both sides of the central differential 11 to ensure clearance with the bevel gears on the drive gear 10 and the differential rear output gear 12. A second tapered bearing 25 is installed between the rear output gear 12 of the differential and the housing. An adjusting shim 26 is installed to the right of the second tapered bearing 25. The adjusting shim 26 is used to adjust the preload between the second tapered bearing 25 and the first tapered bearing 20. The rear output shaft 13 is rigidly connected to the rear output gear 12 of the differential via a spline. A ball bearing 27 is installed between its rear end and the housing. The rear output flange 14 is rigidly connected to the rear output shaft 13 via a spline. In other words, the rear output gear 12 of the differential is rigidly connected to the rear output flange 14, which externally connects to the rear drive shaft of the vehicle. The shaft containing the intermediate gear 15 is supported within the housing by two ball bearings 28 on both sides, and the shaft containing the front output gear 16 is supported within the housing by two ball bearings 29 on both sides. The drive gear 10 meshes with the intermediate gear 15, and the intermediate gear 15 meshes with the front output gear 16. The shaft containing the front output gear 16 is rigidly connected to the front output flange 17 via a spline, meaning that power is transmitted from the drive gear 10 to the front output flange 17. The front output flange 17 is externally connected to the vehicle's front drive shaft in the entire vehicle.

[0025] See attached document Figure 1 , 2 3, 4. During normal driving, the four-wheel drive vehicle is in 4H four-wheel drive mode. The internal spline on the right side of the input shaft 1 connects to the external spline of the high / low gear sleeve 6. The internal spline of the high / low gear sleeve 6 connects to the external spline of the main shaft 7. The external spline of the main shaft 7 connects to the internal spline of the central differential 11. The central differential 11 distributes power to the drive gear 10 and the rear output gear 12 of the differential via planetary bevel gears. The drive gear 10 transmits power to the front output flange 17, and the rear output gear 12 of the differential transmits power to the rear output flange 14. When the vehicle turns, the front and rear wheel speeds are inconsistent, causing the rear output flange 14 and the front output flange 17 to rotate at different speeds. Under the action of the central differential 11, the drive gear 10 and the rear output gear 12 of the differential form a speed difference, preventing gear wear and damage.

[0026] See attached document Figure 1 , 2 3.5. When driving a four-wheel drive vehicle in desert, mud, or deep snow conditions, the driver needs to switch to the 4HL four-wheel drive lock position. The four-wheel drive lock sleeve 9 slides to the right, and the right side of the inner spline of the four-wheel drive lock sleeve 9 is rigidly connected to the outer spline of the drive gear 10. The left side of the inner spline of the four-wheel drive lock sleeve 9 is rigidly connected to the outer spline of the four-wheel drive lock hub 8. The inner spline of the four-wheel drive lock hub 8 is rigidly connected to the outer spline of the main shaft 7. This can be understood as follows: after switching to the 4HL four-wheel drive lock position, the drive gear 10 is rigidly connected to the main shaft 7, the central differential 11 no longer functions as a differential, and the drive gear 10 is rigidly connected to the rear output gear 12 of the differential. The drive gear 10 transmits power to the rear output flange 14 and simultaneously transmits power to the front output flange 17 through gear meshing. This achieves a 50:50 power distribution between the front and rear drive shafts, improving the four-wheel drive vehicle's ability to traverse desert, mud, or deep snow conditions.

[0027] See attached document Figure 1 , 2 When encountering situations requiring off-road extrication, the driver moves the high / low gear sleeve 6 to slide to the right on the main shaft 7. The external spline of the high / low gear sleeve 6 connects with the internal spline of the planetary carrier 3. The high / low gear sleeve 6 rotates at the same speed as the planetary carrier 3. According to the planetary structure reduction ratio, the speed is reduced and the torque is increased. Finally, the increased torque is transmitted to the rear output flange 14 and the front output flange 17 to provide maximum power and traction for off-road extrication of four-wheel drive vehicles.

[0028] This invention utilizes an all-gear transmission for front and rear axle power distribution, avoiding the chain stretching and tooth skipping problems associated with traditional transfer case chain drives. It is equipped with a central differential 11 to compensate for the speed difference between the front and rear wheels during cornering, preventing gear damage to the transmission system. The transfer case features a four-wheel drive mechanical lock, which, when locked, achieves a 50:50 power distribution between the front and rear drive shafts, improving traction in desert, muddy, or deep snow conditions.

[0029] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A full-time, all-gear transmission four-wheel drive transfer case, characterized in that: The system includes a main shaft (7) and a planetary gear mechanism, the input shaft (1) of which is connected to the main shaft (7); the main shaft (7) is provided with a drive gear (10), a central differential (11), and a differential rear output gear (12), the central differential (11) being located between the drive gear (10) and the differential rear output gear (12); the main shaft (7) is connected to the central differential (11), the central differential (11) distributing power to the drive gear (10) and the differential rear output gear (12) through its planetary bevel gears, the drive gear (10) and the differential rear output gear (12) rotating differentially on the main shaft (7); the differential rear output gear (12) is connected to the rear output shaft (13), the rear output shaft (13) of which... The end is connected to the output flange (14); the drive gear (10) meshes with the intermediate gear (15), the intermediate gear (15) meshes with the front output gear (16), the drive gear (10), the intermediate gear (15) and the front output gear (16) are arranged in parallel from top to bottom, and the shaft where the front output gear (16) is located is connected to the front output flange (17); the power is transmitted from the input shaft (1) and the main shaft (7) of the planetary gear mechanism to the central differential (11) and then splits into two paths, one path is transmitted to the front output flange (17) via the drive gear (10), the intermediate gear (15) and the front output gear (16); the other path is transmitted to the rear output flange (14) via the differential rear output gear (12) and the rear output shaft (13).

2. The all-time all-gear transmission four-wheel drive transfer case according to claim 1, characterized in that: The main shaft (7) is provided with a four-wheel drive locking gear hub (8). The internal spline of the four-wheel drive locking gear hub (8) is connected to the external spline of the main shaft (7). The external spline of the four-wheel drive locking gear hub (8) is connected to the internal spline of the four-wheel drive locking gear sleeve (9). The four-wheel drive locking gear hub (8) and the four-wheel drive locking gear sleeve (9) are arranged close to the left side of the drive gear (10). After the four-wheel drive locking gear sleeve (9) slides to the right, the right side of the internal spline of the four-wheel drive locking gear sleeve (9) is connected to the external spline of the drive gear (10), and the left side of the internal spline of the four-wheel drive locking gear sleeve (9) is connected to the external spline of the four-wheel drive locking gear hub (8).

3. A full-time, all-gear transmission four-wheel drive transfer case according to claim 2, characterized in that: The input shaft (1) and main shaft (7) of the planetary gear mechanism are connected by a high-low gear sleeve (6). The internal spline of the high-low gear sleeve (6) is connected to the external spline of the main shaft (7). The external spline of the high-low gear sleeve (6) is connected to the internal spline of the input shaft (1) of the planetary gear mechanism or the internal spline of the planet carrier (3) of the planetary gear mechanism. When the external spline of the high-low gear sleeve (6) is connected to the internal spline of the input shaft (1), the rotational speed of the high-low gear sleeve (6) is the same as that of the input shaft (1). When the high-low gear sleeve (6) slides to the right on the main shaft (7) and the external spline of the high-low gear sleeve (6) is connected to the internal spline of the planet carrier (3), the rotational speed of the high-low gear sleeve (6) is the same as that of the planet carrier (3).

4. A full-time, all-gear transmission four-wheel drive transfer case according to claim 3, characterized in that: The external spline of the main shaft (7) is connected to the internal spline of the central differential (11).

5. A full-time, all-gear transmission four-wheel drive transfer case according to claim 3, characterized in that: The inner bore of the drive gear (10) is press-fitted with a needle roller bearing (21); the inner bore of the differential output gear (12) is press-fitted with a bushing (24).

6. A full-time, all-gear transmission four-wheel drive transfer case according to claim 3, characterized in that: The shaft containing the front output gear (16) is connected to the front output flange (17) via a spline. The rear output gear (12) of the differential is connected to the rear output shaft (13) via a spline. The rear output flange (14) is connected to the rear output shaft (13) via a spline.

7. The all-time all-gear transmission four-wheel drive transfer case according to claim 3, characterized in that: The planetary gear mechanism includes an input shaft (1), a planetary carrier baffle (2), a planetary carrier (3), planetary gears (4), and a planetary gear shaft (5). The planetary carrier baffle (2), the planetary gear shaft (5), and the planetary gears (4) are all mounted on the planetary carrier (3). The input shaft (1) meshes with the planetary gears (4) through gears. The planetary gears (4) are mounted on the planetary carrier (3) through the planetary gear shaft (5). The planetary carrier baffle (2) is fixed to the left side of the planetary gears (4) through the planetary gear shaft (5). The input shaft (1) is provided with an annular step. The planetary carrier baffle (2) is located on the annular step and blocks the input shaft (1), which plays an axial limiting role. The tapered surface on the left side of the planetary gear shaft (5) matches the chamfer of the through hole on the planetary carrier baffle (2) to form a limit. The right end of the planetary gear shaft (5) is a hollow structure, and the outer edge of the right end is riveted to fit the right end face of the planetary carrier (3).

8. The all-time all-gear transmission four-wheel drive transfer case according to claim 3, characterized in that: The input shaft (1), main shaft (7), drive gear (10), central differential (11), differential rear output gear (12), rear output shaft (13) and rear output flange (14) are located on the same axis.

9. A method of using the full-time all-gear transmission four-wheel drive transfer case according to any one of claims 3-8, characterized in that... Includes three modes: Mode A is for daily driving of a four-wheel drive vehicle, which is in 4H four-wheel drive gear mode. The central differential (11) distributes power to the drive gear (10) and the differential rear output gear (12) through its planetary bevel gears. The drive gear (10) transmits power to the front output flange (17), and the differential rear output gear (12) transmits power to the rear output flange (14). When the vehicle turns, the front and rear wheels rotate at different speeds, which causes the rear output flange (14) and the front output flange (17) to rotate at different speeds. Under the action of the central differential (11), the drive gear (10) and the differential rear output gear (12) form a speed difference to avoid gear damage. In mode B, to improve traffic capacity, the driver switches to the 4HL four-wheel drive lock position. At this time, the four-wheel drive lock sleeve (9) slides to the right. The right side of the inner spline of the four-wheel drive lock sleeve (9) is connected to the outer spline of the drive gear (10), the left side of the inner spline of the four-wheel drive lock sleeve (9) is connected to the outer spline of the four-wheel drive lock hub (8), and the inner spline of the four-wheel drive lock hub (8) is connected to the outer spline of the main shaft (7). That is, after switching to the 4HL four-wheel drive lock position, the drive gear (10) is connected to the main shaft (7), the central differential (11) no longer plays a differential role, the drive gear (10) is connected to the rear output gear (12) of the differential, and the power is transmitted to the rear output flange (14) and the front output flange (17) in a 50:50 ratio, thereby improving the passability of the four-wheel drive vehicle. Mode C is for vehicle extrication. The high and low gear sleeve (6) is slid to the right on the main shaft (7) by the shift fork, so that the high and low gear sleeve (6) is connected to the planetary carrier (3). At this time, the rotation speed of the high and low gear sleeve (6) is the same as that of the planetary carrier (3). According to the planetary structure reduction ratio, the speed is reduced and the torque is increased. Finally, the increased torque is transmitted to the rear output flange (14) and the front output flange (17) to provide maximum power and traction for four-wheel drive vehicles to get out of trouble off-road.

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