Differential transfer case special for special vehicle

Abstract

The invention discloses a special differential transfer case for special vehicles, which comprises a case body, a main input shaft system, a left planetary differential shaft system, a right planetary differential shaft system, a differential input shaft system, a left output shaft system and a right output shaft system, the left planetary differential shaft system and the right planetary differential shaft system are symmetrically arranged on the case body, and the left output shaft system and the right output shaft system are symmetrically arranged on the lower part of the case body. And the differential input shaft system is in transmission connection with the left planetary differential shaft system or the right planetary differential shaft system. The input shafts and the output shafts of the two planetary differential shaft systems are of a split structure, the main input shaft transmits power to the planetary input shaft, the power is transmitted to the two output shaft systems through the planetary output shaft, and normal running of a special vehicle is achieved; the differential input shaft system transmits torque to the two planet output shafts and then transmits the torque to the two output shaft systems, reverse-direction same-speed rotation of the two output shaft systems is achieved, in-situ turning of the special vehicle can be achieved, the turning radius is reduced, the passing capacity of the special vehicle is improved, and the passing capacity of the special vehicle under severe road conditions is improved.

Description

Technical Field

[0001] The invention relates to the field of special vehicle transmission, in particular to a special vehicle dedicated differential transfer case. Background Art

[0002] Special vehicles with multi-axle drive (such as fire trucks and engineering rescue vehicles) are generally equipped with a transfer case on their chassis, which distributes the power output from the transmission to each drive axle to overcome the greater driving resistance of the vehicle on poor roads and roadless areas. The transfer cases of existing special vehicles are usually automobile transfer cases. Special vehicles are generally longer in body and have a large turning radius, which results in insufficient vehicle traffic capacity and a restricted working environment. Summary of the invention

[0003] In view of this, the present invention proposes a differential transfer case dedicated to special vehicles, which can realize on-the-spot turning of special vehicles and improve the passing ability of special vehicles.

[0004] To achieve the above object, the present invention adopts the following technical solutions: The special vehicle special differential transfer case of the present invention comprises a housing, a main input shaft system, and also comprises a left planetary differential shaft system, a right planetary differential shaft system, a differential input shaft system, a left output shaft system and a right output shaft system, wherein the main input shaft system comprises a main input shaft rotatably arranged on the upper part of the housing and a main input gear arranged at one end of the main input shaft, the left planetary differential shaft system and the right planetary differential shaft system have the same structure and are symmetrically arranged on the housing, the left planetary differential shaft system and the right planetary differential shaft system are located below the main input shaft system, the left planetary differential shaft system comprises a left planetary input shaft and a left planetary output shaft coaxially arranged, the left planetary input shaft is provided with a left planetary input gear meshing with the main input gear, the left planetary output shaft is provided with a left planetary output gear, the left planetary input shaft and the left planetary output shaft are connected by transmission through a left sun gear system; the right planetary input gear of the right planetary differential shaft system is meshed with the main input gear, and the right sun gear system of the right planetary differential shaft system is connected by transmission with the left sun gear system; The left output shaft system and the right output shaft system are symmetrically arranged at the lower part of the casing, the differential input shaft system is arranged between the left output shaft system and the right output shaft system, the differential input shaft system is drivingly connected to the left sun gear system or the right sun gear system of the right planetary differential shaft system, the left output shaft system is drivingly connected to the left planetary output gear, and the right output shaft system is drivingly connected to the right planetary output gear of the right planetary differential shaft system.

[0005] Beneficial effects: The input shaft and output shaft of the two planetary differential shaft systems of the present invention are split structures. The main input shaft transmits power to the planetary input shaft, and then transmits it to the two output shaft systems through the sun gear system and the planetary output shaft, thereby realizing the normal driving of the special vehicle; the differential input shaft system can transmit torque to the two planetary output shafts through the sun gear system, and transmit it to the two output shaft systems through the planetary output gears, thereby realizing the two output shaft systems rotating in opposite directions at the same speed, which can realize the special vehicle's on-the-spot turning, reduce the turning radius, improve the special vehicle's passing ability, and improve its passability under harsh road conditions; when both the main input shaft and the differential input shaft have power input, the two output shaft systems can realize differential and same-direction rotation, meeting the turning requirements during driving.

[0006] Preferably, the left sun gear system includes a left inner gear ring, a left sun gear, a left planetary carrier and a plurality of left planetary gears, the left inner gear ring has a mounting portion and a gear ring portion, the mounting portion is rotatably connected to the housing through a bearing, the outer ring of one end portion of the left planetary carrier is rotatably connected to the inner ring of the mounting portion through a bearing, and the inner ring of the left planetary carrier is keyed to the end portion of the left planetary output shaft; each of the left planetary gears is mounted on the disc portion of the left planetary carrier through a bearing and a planetary shaft, and the left planetary gear is located in the left inner gear ring and meshes with the gear ring portion; the left sun gear is rotatably mounted on the middle portion of the left planetary output shaft through a bearing, and the left sun gear meshes with the left planetary gear; the right end portion of the left sun gear is provided with a left synchronous gear, and the left synchronous gear and the right synchronous gear of the right sun gear system mesh with each other; the differential input shaft system is transmission-connected to the left synchronous gear or to the right synchronous gear.

[0007] Preferably, the left output shaft system includes a left output shaft whose two ends are rotatably matched with the casing, the two ends of the left output shaft extend outside the casing and are both provided with left output flanges, and the rear end of the left output shaft is provided with a left output gear meshing with the left planetary output gear; the right output shaft system includes a right output shaft whose two ends are rotatably matched with the casing, the two ends of the right output shaft extend outside the casing and are both provided with right output flanges, and the rear end of the right output shaft is provided with a right output gear meshing with the right planetary output gear.

[0008] Preferably, the differential input shaft system includes a differential input shaft rotatably disposed in the housing and a differential input gear disposed on the differential input shaft, wherein the differential input gear is meshed with the left synchronous gear or the right synchronous gear; and both ends of the differential input shaft are rotatably connected to the housing through bearings.

[0009] Compared with the prior art, the input shaft and output shaft of the two planetary differential shaft systems of the present invention are split structures. The main input shaft transmits power to the planetary input shaft, and then transmits it to the two output shaft systems through the sun gear system and the planetary output shaft, thereby realizing the normal driving of the special vehicle; the differential input shaft system can transmit torque to the two planetary output shafts through the sun gear system, and transmit it to the two output shaft systems through the planetary output gears, thereby realizing the two output shaft systems rotating in opposite directions at the same speed, which can realize the special vehicle's on-the-spot turning, reduce the turning radius, improve the special vehicle's passing ability, and improve its passing ability under harsh road conditions; when both the main input shaft and the differential input shaft have power input, the two output shaft systems can realize differential and same-direction rotation, meeting the turning requirements during driving. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a structural schematic diagram of the present invention.

[0011] Figure 2 yes Figure 1 Schematic diagram of PP section view.

[0012] Figure 3 yes Figure 1 NN-direction cross-sectional schematic diagram.

[0013] Figure 4 This is the working state of the present invention Figure 1 (The differential input shaft system has no external power input, and the input power of the main input shaft system is clockwise torque).

[0014] Figure 5 This is the working state of the present invention Figure 2 (The differential input shaft system has no external power input, and the input power of the main input shaft system is counterclockwise torque).

[0015] Figure 6 This is the working state of the present invention Figure 3 (The main input shaft system has no external power input, and the input power of the differential input shaft system is clockwise torque). DETAILED DESCRIPTION

[0016] The following is a detailed description of an embodiment of the present invention in conjunction with the accompanying drawings. This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and a specific operation process are given, but the protection scope of the present invention is not limited to the following embodiment.

[0017] It should be noted that, in the description of the present invention, relational terms such as “first” and “second” are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0018] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected" and "connection" that may appear 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 an indirect connection through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0019] In the description of the present invention, the terms "front", "rear", "left" and "right" are used as the Figure 1 As a benchmark, Figure 1 The right direction in the text is right, and the opposite direction is left; Figure 1 The forward direction is forward, and the reverse direction is backward.

[0020] like Figure 1-3 As shown, the special vehicle differential transfer case described in the present invention includes a case 1, a main input shaft system A, and also includes a left planetary differential shaft system B1, a right planetary differential shaft system B2, a differential input shaft system D, a left output shaft system C1 and a right output shaft system C2. The main input shaft system A includes a main input shaft A1 rotatably arranged on the upper part of the case 1 and a main input gear A2 arranged at the front end of the main input shaft A1. The main input gear A2 is inside the case 1 and close to the front side wall of the case 1; the left planetary differential shaft system B1 and the right planetary differential shaft system B2 are symmetrically arranged on the case 1 and are located below the main input shaft A1. Among them, the structures of the left planetary differential shaft system B1 and the right planetary differential shaft system B2 are the same. Taking the left planetary differential shaft system B1 as an example: the left planetary differential shaft system B1 includes a left sun gear system and a coaxially arranged left planetary input shaft B1.1 and a left planetary output shaft B1.2. The left planetary input shaft B1.1 is provided with a left planetary input gear B1.3 meshing with the main input gear A2, and the left planetary output shaft B1.2 is provided with a left planetary output gear B1.4; the left sun gear system includes a left inner ring gear B1.5, a left sun gear B1.6, a left planetary carrier B1.7 and a plurality of left planetary gears B1.8 (four in this embodiment, of course, it can also be three or more), and the left inner ring gear B1.5 has There are a mounting part and a gear ring part, the mounting part is rotatably connected to the housing 1 through a bearing, the outer ring of the front end of the left planetary carrier B1.7 is rotatably connected to the inner ring of the mounting part through a bearing, and the inner ring of the front end of the left planetary carrier B1.7 is key-connected to the left planetary output shaft B1.2; each left planetary gear B1.8 is mounted on the disc part of the left planetary carrier B1.7 through a bearing and a planetary shaft, and the left planetary gear B1.8 is located in the left inner gear ring B1.5 and meshes with the gear ring part; the left sun gear B1.6 is rotatably mounted on the middle part of the left planetary output shaft B1.2 through a bearing, and the left sun gear B1.6 meshes with the left planetary gear B1.8; the rear end of the left sun gear B1.6 is sleeved with a left synchronous gear B1.9; Combination Figure 3It can be seen that the right planetary shaft system includes a right sun gear system, a right planetary input shaft B2.1 and a right planetary output shaft B2.2. The right planetary input shaft B2.1 is provided with a right planetary input gear B2.3 meshing with the main input gear A2, and the right planetary output shaft B2.2 is provided with a right planetary output gear B2.4; the right sun gear system includes a right inner gear ring B2.5, a right sun gear B2.6, a right planetary carrier B2.7 and a plurality of right planetary gears B2.8 (four in this embodiment, but of course three or more), the right inner gear ring B2.5 has a mounting portion and a gear ring portion, the mounting portion is rotatably connected to the housing 1 through a bearing, the outer ring of the front end portion of the right planetary carrier B2.7 is rotatably connected to the inner ring of the mounting portion of the right inner gear ring B2.5 through a bearing, and the right planetary carrier B2. The inner ring of the front end of 7 is key-connected with the right planetary output shaft B2.2; each right planetary gear B2.8 is installed on the disc part of the right planetary carrier B2.7 through a bearing and a right planetary shaft, and the right planetary gear B2.8 is located in the right inner gear ring B2.5 and meshes with its gear ring part; the right sun gear B2.6 is rotatably installed on the middle part of the right planetary output shaft B2.2 through a bearing, and the right sun gear B2.6 can rotate relative to the right planetary output shaft, and the right sun gear B2.6 meshes with the right planetary gear B2.8; the right end of the right sun gear B2.6 is sleeved with a right synchronous gear B2.9, and the left synchronous gear B1.9 meshes with the right synchronous gear B2.9, so as to realize the transmission connection between the left sun gear system and the right sun gear system, and further realize the transmission connection between the left planetary differential shaft system and the right-left planetary differential shaft system; The left planetary input gear B1.3 and the right planetary input gear B2.3 are arranged at intervals, and both the left planetary input gear B1.3 and the right planetary input gear B2.3 are meshed with the main input gear A2. The main input gear A2 drives the left planetary input shaft B1.1 and the right planetary input shaft B2.1 to rotate respectively through the left input gear and the right planetary input gear B2.3. When the main input shaft system A is working, the two planetary differential shaft systems can realize synchronous rotation in the same direction.

[0021] Combination Figure 1-3 It can be seen that the left output shaft system C1 and the right output shaft system C2 are symmetrically arranged at the lower part of the housing 1, the differential input shaft system D is located between the left output shaft system C1 and the right output shaft system C2, and the differential input shaft system D is installed near the vertical center axis F of the housing 1, the left output shaft system C1 is located at the lower left of the left planetary differential shaft system B1, and the right output shaft system C2 is located at the lower right of the right planetary differential shaft system B2; The differential input shaft system D is connected to the left planetary differential shaft system B1 by transmission, and includes a differential input shaft D1 rotatably arranged in the housing 1 and a differential input gear D2 (located at the rear end of the differential input shaft D1) arranged on the differential input shaft D1. The differential input gear D2 is meshed with the left synchronous gear B1.9, and the torque of the differential input shaft system can be synchronously transmitted to the right planetary differential shaft system B2 through the left planetary differential shaft system B1. Among them, one end of the differential input shaft D1 is located inside the housing 1 and is rotatably connected to the housing 1 through a bearing, and the other end of the differential input shaft D1 is located outside the housing 1 and has a flat keyway. Of course, in actual installation, the differential input shaft system D can also be installed at a position close to the right output shaft system C2, so that the differential input gear D2 is meshed with the right synchronous gear B2.9, and the right planetary differential shaft system B2 is used to synchronously transmit power to the left planetary differential shaft system B1.

[0022] Combination Figure 1 and Figure 3 It can be seen that the left output shaft system C1 and the right output shaft system C2 have the same structure. The left output shaft system C1 includes a left output shaft rotatably set in the casing 1 and a left output gear keyed to the left output shaft. The left output gear is meshed with the left planetary output gear B1.4. Both ends of the left output shaft extend to the outside of the casing 1 and are both provided with left output flanges; the right output shaft system C2 includes a right output shaft C2.1 rotatably set in the casing 1 and a right output gear C2.2 keyed to the right output shaft C2.1. The right output gear C2.2 is meshed with the right planetary output gear B2.4. Both ends of the right output shaft C2.1 extend to the outside of the casing 1 and are both provided with right output flanges C2.3.

[0023] During actual installation, the main input shaft A1 is connected to the engine, and the engine provides power for normal driving; the differential input shaft D1 is connected to the motor of the special vehicle, and the motor can transmit the torque to the two planetary output shafts through the differential input shaft D1, the left sun gear system, and the right sun gear system, and transmit the torque to the output shaft system through the planetary differential shaft system, so that the left output shaft and the right output shaft rotate at the same speed and in opposite directions, thereby realizing the special vehicle's on-the-spot turning.

[0024] During the actual installation, the two ends of the main input shaft A1 are rotatably connected to the housing 1 through bearings, and the two ends of the main input shaft A1 are key-connected with the main input flange A3, which is connected to the engine through the drive axle. The installation of the left planetary differential shaft system and the right planetary differential shaft system is exactly the same. Take the left planetary differential shaft system as an example: The left planetary input shaft B1.1 is rotatably connected to the housing 1 through two bearings, so that the left planetary input shaft B1.1 can rotate relative to the housing; the outer ring of the mounting part of the left inner gear ring B1.5 is rotatably connected to the housing 1 through a bearing, and the inner ring of the mounting part is a step hole, whose small diameter hole section is key-connected to the left planetary input shaft B1.1, and whose large diameter hole section is rotatably connected to the left planet carrier B1.7 through a bearing. When the left planetary input shaft B1.1 rotates, the left inner gear ring B1.5 can be driven to rotate, and when there is no power input to the left planetary input shaft B1.1, the left inner gear ring B1.5 is in a non-rotating state; the right end of the left planetary output shaft B1.2 is rotatably connected to the housing 1 through a pair of bearings arranged at intervals, and the left planetary output gear B1.4 is located on the left planetary output shaft B1.2 between the two bearings; The left planetary carrier B1.7 is keyed to the left end of the left planetary output shaft B1.1. The left planetary carrier B1.7 is located inside the left inner gear ring B1.5. The right end of the left sun gear B1.6 extends out of the left inner gear ring B1.5. The left synchronous gear B1.9 (a large gear) can be installed on the right end of the left sun gear B1.6. Both ends of the left output shaft and the right output shaft are keyed to output flanges, which can be connected to the drive axle of the special vehicle to realize torque transmission.

[0025] During actual installation, the differential input gear D2 is a small gear, and the left synchronous gear B1.9 is a large gear to achieve speed reduction transmission; the left planetary output gear B1.4 is a small gear, and the left output gear is a large gear to further reduce speed, thereby achieving speed reduction transmission of the differential torque and improving the passing ability of special vehicles.

[0026] The present invention has three states: normal driving, turning and turning in place. When the engine is working, the engine transmits power to the main input shaft A1, the left planetary input gear B1.3 and the right planetary input gear B2.3 are both meshed with the main input gear A2, and the main input shaft A1 can transmit torque to the left planetary input shaft B1.1 and the right planetary input shaft B2.1 through the main input gear A2, the left planetary input gear B1.3 and the right planetary input gear B2.3 respectively. The rotation directions of the left planetary input shaft B1.1 and the right planetary input shaft B2.1 are consistent, and are opposite to the main input shaft A1; The working principles of the left sun gear system and the right sun gear system are the same. Take the left sun gear system as an example: since the left inner ring gear B1.5 is key-connected with the left planetary input shaft B1.1, the left inner ring gear B1.5 rotates synchronously with the left planetary input shaft B1.1, and the left inner ring gear B1.5 and the left sun gear B1.6 are both meshed with the left planetary gear B1.8. The left planetary gear B1.8 transmits the torque to the left planetary carrier B1.7, and outputs the torque to the left planetary output shaft B1.2 through the left planetary carrier B1.7. Since the left sun gear B1.6 and the left planetary output shaft B1.2 are connected by bearings, the left sun gear B1.6 and the left synchronous gear B1.9 (a large gear) remain stationary relative to the left planetary output shaft B1.2; the left planetary output gear B1.4 is meshed with the left output gear, and the left output shaft transmits the torque to the left output shaft through the left planetary output gear B1.4 and the left output gear, and then transmits the torque to the travel wheel axle of the special vehicle through the left output shaft. The main input shaft A1 of the present invention divides the torque into two parts and transmits it to two planetary output shaft systems with the same structure through the main input gear A2. The two planetary gear systems rotate in the same direction and at the same speed. Each planetary gear system transmits the torque to the output shaft system through the planetary output gear, so that the two output shaft systems rotate in the same direction and at the same speed, thereby realizing the normal driving of the special vehicle.

[0027] When the torque transmitted to the main input shaft A1 by the engine is clockwise, the main input shaft A1 drives the two planetary input shafts to rotate counterclockwise through the main input gear A2, the left planetary input gear B1.3 and the right planetary input gear B2.3. Each planetary input shaft drives the corresponding planetary output shaft to rotate counterclockwise through the sun gear system. The planetary output gear of each planetary output shaft meshes with the output gear of the output shaft system, thereby realizing the clockwise rotation of the two output shafts at the same speed. For details, see Figure 4 Similarly, when the main input shaft A1 rotates counterclockwise, the left output shaft and the right output shaft C2.1 rotate counterclockwise at the same speed. Figure 5 .

[0028] When the motor (such as a hydraulic motor) is working and the engine is not working, the motor transmits torque to the differential input shaft D1, the differential input gear D2 and the left synchronous gear B1.9 are meshed, the left synchronous gear B1.9 inputs torque to the left sun gear B1.6, the left sun gear B1.6 transmits torque to the left planetary carrier B1.7, and the left planetary output shaft B1.2 is driven to rotate synchronously through the left planetary carrier B1.7 while the left inner gear B1.5 remains stationary; since the left synchronous gear B1.9 and the right synchronous gear B2.9 are meshed, the rotation of the right planetary output shaft B2.2 can be realized; the left planetary output shaft B1.2 transmits torque to the left output shaft through the left planetary output gear B1.4 and the left output gear, and the right planetary output shaft B2.2 transmits torque to the right output shaft C2.1 through the right planetary output gear B2.4 and the right output gear. In this working state, the left synchronous gear B1.9 and the right synchronous gear B2.9 mesh with each other, and their rotation directions are opposite, so that the two planetary output shafts rotate at the same speed in opposite directions, and the two output shaft systems also rotate at the same speed in opposite directions, so that the left and right wheels of the special vehicle rotate in opposite directions, enabling the special vehicle to turn on the spot and improve its passability.

[0029] Specifically, when the differential input shaft D1 rotates clockwise, the differential input gear D2 meshes with the left synchronous gear B1.9, and the left synchronous gear B1.9 rotates counterclockwise. The left synchronous gear B1.9 transmits the torque to the left sun gear system, realizing the counterclockwise rotation of the left planetary output shaft B1.2. Since the left planetary output gear B1.4 meshes with the left output gear, the clockwise rotation of the left output shaft is realized; the left synchronous gear B1.9 meshes with the right synchronous gear B2.9, and the right synchronous gear B2.9 rotates clockwise, causing the right output shaft C2.1 to rotate counterclockwise, realizing the left output shaft and the right output shaft C2.1 to rotate in opposite directions at the same speed. For details, see Figure 6 Conversely, when the differential input shaft D1 rotates counterclockwise, the left output shaft rotates counterclockwise and the right output shaft C2.1 rotates clockwise.

[0030] When the engine and motor work at the same time, the special vehicle can turn left and right: when the engine is working, the torque applied by the engine to the two output shaft systems through the main input shaft system A and the two planetary gear systems rotates in the same direction and at the same speed, and the speed is recorded as R1; the torque applied by the motor to the two output shaft systems through the differential input shaft system D and the two planetary gear systems rotates in the opposite direction and synchronously, and the speeds are R2 and - R2 respectively. The final torques of the two output shaft systems are R1+ R2 and R1- R2 respectively, thereby realizing the turning of the special vehicle.

[0031] Finally, it should be emphasized that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions recorded in the aforementioned embodiments without creative work, or replace some of the technical features therein with equivalents. Therefore, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A special vehicle differential transfer case, comprising a housing and a main input shaft system, characterized in that: It also includes a left planetary differential shaft system, a right planetary differential shaft system, a differential input shaft system, a left output shaft system and a right output shaft system, the main input shaft system includes a main input shaft rotatably arranged on the upper part of the housing and a main input gear arranged at one end of the main input shaft, the left planetary differential shaft system and the right planetary differential shaft system have the same structure and are symmetrically arranged on the housing, the left planetary differential shaft system and the right planetary differential shaft system are located below the main input shaft system, the left planetary differential shaft system includes a left planetary input shaft and a left planetary output shaft coaxially arranged, the left planetary input shaft is provided with a left planetary input gear meshing with the main input gear, the left planetary output shaft is provided with a left planetary output gear, the left planetary input shaft and the left planetary output shaft are connected by transmission through the left sun gear system; the right planetary input gear of the right planetary differential shaft system is meshed with the main input gear, and the right sun gear system of the right planetary differential shaft system is connected by transmission with the left sun gear system; The left output shaft system and the right output shaft system are symmetrically arranged at the lower part of the casing, the differential input shaft system is arranged between the left output shaft system and the right output shaft system, the differential input shaft system is drivingly connected to the left sun gear system or the right sun gear system of the right planetary differential shaft system, the left output shaft system is drivingly connected to the left planetary output gear, and the right output shaft system is drivingly connected to the right planetary output gear of the right planetary differential shaft system.

2. The special vehicle differential transfer case according to claim 1, characterized in that: The left sun gear system includes a left inner gear ring, a left sun gear, a left planetary carrier and a plurality of left planetary gears, the left inner gear ring has a mounting portion and a gear ring portion, the mounting portion is rotatably connected to the housing through a bearing, the outer ring of one end portion of the left planetary carrier is rotatably connected to the inner ring of the mounting portion through a bearing, and the inner ring of the left planetary carrier is keyed to the end portion of the left planetary output shaft; each of the left planetary gears is mounted on the disc portion of the left planetary carrier through a bearing and a planetary shaft, the left planetary gear is located in the left inner gear ring and meshes with the gear ring portion; the left sun gear is rotatably mounted on the middle portion of the left planetary output shaft through a bearing, and the left sun gear meshes with the left planetary gear; the right end portion of the left sun gear is provided with a left synchronous gear, and the left synchronous gear and the right synchronous gear of the right sun gear system mesh with each other; the differential input shaft system is transmission-connected to the left synchronous gear or to the right synchronous gear.

3. The differential transfer case for special vehicles according to claim 2, characterized in that: The left output shaft system includes a left output shaft whose two ends are rotatably matched with the housing, the two ends of the left output shaft extend outside the housing and are both provided with left output flanges, and the rear end of the left output shaft is provided with a left output gear meshing with the left planetary output gear; the right output shaft system includes a right output shaft whose two ends are rotatably matched with the housing, the two ends of the right output shaft extend outside the housing and are both provided with right output flanges, and the rear end of the right output shaft is provided with a right output gear meshing with the right planetary output gear.

4. The differential transfer case for special vehicles according to claim 2, characterized in that: The differential input shaft system includes a differential input shaft rotatably arranged in the housing and a differential input gear arranged on the differential input shaft, wherein the differential input gear is meshed with the left synchronous gear or the right synchronous gear; both ends of the differential input shaft are rotatably connected to the housing through bearings.

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