阅读说明：本技术 三轮车中央驱动自适应变速总成 (Central driving self-adaptive speed change assembly of tricycle ) 是由 薛荣生 张引航 陈俊杰 王靖 陈同浩 舒雷 谭志康 邓天仪 邓云帆 梁品权 颜昌 于 2020-12-16 设计创作，主要内容包括：本发明公开了一种三轮车中央驱动自适应变速总成,包括动力输入机构、主轴、高速挡传动机构、低速挡传动机构、前后换挡切换机构、动力输出机构和倒挡传动机构。采用以上技术方案的,使三轮车无论在前进挡还是倒挡,都能够根据阻力情况,自适应匹配实际的行驶工况与电机工况,使三轮车具有强大的爬坡和重载能力的同时,电机始终处于高效平台上,大大提高了电机在爬坡和重载情况下的效率,降低了电机能耗,尤其是在不切断驱动力的情况下,前进挡和倒挡都能够自适应随行驶阻力变化自动进行高低速换挡变速；而且,整体采用中央驱动式安装,直接将动力传递给差速器,合理利用了三轮车的底盘空间,降低了装配难度。(The invention discloses a central driving self-adaptive speed change assembly of a tricycle, which comprises a power input mechanism, a main shaft, a high-speed gear transmission mechanism, a low-speed gear transmission mechanism, a front and rear gear shifting switching mechanism, a power output mechanism and a reverse gear transmission mechanism. By adopting the technical scheme, the tricycle can be adaptively matched with the actual running condition and the motor condition according to the resistance condition no matter in forward gear or reverse gear, the tricycle has strong climbing and heavy-load capacity, and meanwhile, the motor is always positioned on a high-efficiency platform, so that the efficiency of the motor under the climbing and heavy-load conditions is greatly improved, the energy consumption of the motor is reduced, and particularly, the forward gear and the reverse gear can be adaptively changed in speed along with the change of the running resistance; and the whole adopts the installation of central drive formula, directly transmits power for differential mechanism, rationally utilizes the chassis space of tricycle, has reduced the assembly degree of difficulty.)

1. The utility model provides a tricycle central authorities drive self-adaptation variable speed assembly which characterized in that: the gear-shifting mechanism comprises a power input mechanism, a main shaft (1), a high-speed gear transmission mechanism, a low-speed gear transmission mechanism, a front and rear gear-shifting switching mechanism, a power output mechanism and a reverse gear transmission mechanism;

the high-speed gear transmission mechanism comprises a friction clutch (5) and an elastic element group (3) for applying pretightening force to the friction clutch (5), the friction clutch (5) comprises an outer plate flower sleeve (5a), an inner plate spiral roller sleeve (5b) and outer friction plates (5c) and inner friction plates (5d) which are alternately arranged between the outer plate flower sleeve (5a) and the inner plate spiral roller sleeve (5b), each outer friction plate (5c) can axially slide along the outer plate flower sleeve (5a), each inner friction plate (5d) can axially slide along the inner plate spiral roller sleeve (5b), the inner plate spiral roller sleeve (5b) is sleeved on the main shaft (1) and forms a spiral transmission pair with the main shaft (1) to enable the inner plate spiral roller sleeve (5b) to axially slide along the main shaft (1), and the power input mechanism can transmit power to a front-back switching machine through the main shaft (1) and the friction clutch (5) in turn to transfer the front-back machine to the switching machine Structuring;

the low-speed gear transmission mechanism comprises a countershaft transmission assembly and an overrunning clutch (9) which is rotatably sleeved on the middle cam sleeve (2), the inner sheet spiral raceway sleeve (5b) and an inner core wheel (9c) of the overrunning clutch (9) can synchronously rotate through a front and back gear shifting switching mechanism, the end faces of the two ends of the middle cam sleeve (2) are respectively matched with the adjacent end face of the inner spiral raceway sleeve (5b) and the adjacent end face of the first-stage speed reduction driving gear (8) of the auxiliary shaft transmission assembly to form end face cams, the primary speed reduction driving gear (8) is rotatably sleeved on the main shaft (1), the power input mechanism can transmit power to the front and rear gear-shifting switching mechanism sequentially through the main shaft (1), the inner sheet spiral roller way sleeve (5b), the middle cam sleeve (2), the auxiliary shaft transmission assembly and the overrunning clutch (9);

the front and rear gear shifting switching mechanism can be switched, or power is directly transmitted to the tricycle differential (10) through the power output mechanism, or power is transmitted to the tricycle differential (10) through the reverse gear transmission mechanism and the power output mechanism in sequence.

2. The tricycle central drive adaptive transmission assembly of claim 1, wherein: the front and rear gear shifting switching mechanism comprises a synchronous sleeve (11) which synchronously rotates with both the outer sheet flower sleeve (5a) and the inner core wheel (9c) and a gear shifting sleeve (12) which is synchronously and rotatably sleeved on the synchronous sleeve (11), wherein the gear shifting sleeve (12) can slide along the synchronous sleeve (11) to be connected with a power output mechanism or a reverse gear transmission mechanism.

3. The tricycle central drive adaptive transmission assembly of claim 2, wherein: the power output mechanism comprises an output shaft (13) parallel to the main shaft (1), and an output shaft input gear (14) and an output shaft output gear (15) which are sleeved on the output shaft (13) in a synchronous rotating mode, wherein the output shaft input gear (14) can be meshed with a gear shifting combination tooth (12a) formed on a gear shifting sleeve (12), and the output shaft output gear (15) is meshed with a differential input gear (10a) of a tricycle differential (10);

the reverse gear transmission mechanism comprises a reverse gear shaft (16) parallel to the main shaft (1) and the output shaft (13) and a reverse gear input gear (17) and a reverse gear output gear (18) which are sleeved on the reverse gear shaft (16) in a synchronous rotating mode, the reverse gear input gear (17) can be meshed with the gear shifting combination teeth (12a), and the reverse gear output gear (18) is meshed with the output shaft input gear (14).

4. The tricycle central drive adaptive transmission assembly of claim 3, wherein: the main shaft (1), the output shaft (13) and the reverse gear shaft (16) are arranged in a triangular shape in space.

5. The tricycle central drive adaptive transmission assembly of claim 2, wherein: the outer piece flower sleeve (5a) comprises a power input part (5a1), a compression fit part (5a2) and a power output part (5a3) which are sequentially connected, the power input part (5a1) and the power output part (5a3) are both of a circular ring structure, the diameter of the power input part (5a1) is larger than that of the power output part (5a3), the synchronous sleeve (11) is sleeved on the power output part (5a3) and is in spline fit with the power output part (5a3), the compression fit part (5a2) is of a circular disc structure, and each outer friction piece (5c) can axially slide along the inner wall of the power input part (5a 1);

inner plate spiral raceway cover (5b) is including inner plate sliding part (5b1) that is the ring structure and friction disc that is the disc structure compress tightly portion (5b2), it is vice to form screw drive between inner plate sliding part (5b1) and main shaft (1), and each inner friction disc (5d) can be followed the outer wall axial slip of inner plate sliding part (5b1), and each outer friction disc (5c) and inner friction disc (5d) are located and compress tightly between cooperation portion (5a2) and friction disc compress tightly portion (5b2), elastic element group (3) and friction disc compress tightly portion (5b2) butt, it is vice to form screw drive between inner plate sliding part (5b1) and main shaft (1).

6. The tricycle central drive adaptive transmission assembly of claim 5, wherein: the outer wall of the main shaft (1) is provided with an outer spiral raceway (1a), a plurality of balls (18) are arranged in the outer spiral raceway (1a), the inner wall of the inner sheet spiral raceway sleeve (5b) is provided with an inner spiral raceway (5b3) matched with the outer spiral raceway (1a), and the balls (18) can roll in the outer spiral raceway (1a) and the inner spiral raceway (5b 3).

7. The tricycle central drive adaptive transmission assembly of claim 2, wherein: the auxiliary shaft transmission assembly comprises an auxiliary shaft (4) parallel to the main shaft (1), a first-stage reduction driven gear (6) and a second-stage reduction driving gear (7), wherein the first-stage reduction driven gear (6) and the second-stage reduction driving gear (7) are sleeved on the auxiliary shaft (4) in a synchronous rotating mode, the first-stage reduction driven gear (6) is meshed with a first-stage reduction driving gear (8), and the second-stage reduction driving gear (7) is meshed with a second-stage reduction driven gear (9b) of an outer ring (9a) of the overrunning clutch (9).

8. The tricycle central drive adaptive transmission assembly of claim 7, wherein: the rolling bodies distributed along the periphery of each inner core wheel (9c) are composed of thick rolling bodies (9d) and thin rolling bodies (9e) which are alternately arranged, two opposite retainers (9f) are arranged on the peripheral surface of the inner core wheel (9c), a circle of annular groove (9f1) is formed in the inner wall of each retainer (9f), and two ends of each thin rolling body (9e) are respectively and slidably inserted into the corresponding annular grooves (9f 1).

9. The tricycle central drive adaptive transmission assembly of claim 1, wherein: the power input mechanism comprises a driving motor (19), an input driving gear (20) and an input driven gear (21), wherein the input driving gear (20) rotates synchronously with a motor shaft (19a) of the driving motor (19), the input driven gear (21) rotates synchronously with the main shaft (1), and the input driven gear (21) is meshed with the input driving gear (20).

10. The tricycle central drive adaptive transmission assembly of claim 1, wherein: the elastic element group (3) is a disc spring sleeved on the main shaft (1) and is arranged between the end face bearing (22) and the inner sheet spiral roller sleeve (5 b).

Technical Field

The invention relates to the technical field of electric drive systems of tricycles, in particular to a tricycle central drive self-adaptive speed change assembly.

Background

With the increasing strictness of environmental regulations, it has become a great trend to replace the tricycle driven by the traditional internal combustion engine with the tricycle adopting the electric driving system.

The existing tricycle electric drive system is limited by a transmission structure, and in the driving process, a driver can control and shift gears according to experience under the condition that the driving resistance cannot be accurately known. Therefore, the situation that the working state of the motor is not matched with the actual running condition of the tricycle often inevitably occurs, and the motor is locked. Especially when the tricycle is in low-speed heavy-load conditions such as starting, climbing, headwind and the like, the motor usually needs to work under the conditions of low efficiency, low rotating speed and high torque, the motor is easy to be damaged accidentally, the maintenance and replacement cost is increased, and meanwhile the endurance mileage of the battery can be directly influenced. For vehicle types with high economic requirements, such as electric logistics vehicles, the traditional variable speed transmission structure obviously cannot well meet the use requirements. In addition, the existing tricycle electric drive system cannot perform self-adaptive gear shifting according to the running resistance under a reverse gear transmission path.

It is urgent to solve the above problems.

Disclosure of Invention

In order to solve the technical problems, the invention provides a tricycle central drive self-adaptive speed change assembly.

The technical scheme is as follows:

a central driving self-adaptive speed change assembly of a tricycle is characterized by comprising a power input mechanism, a main shaft, a high-speed gear transmission mechanism, a low-speed gear transmission mechanism, a front and rear gear shifting switching mechanism, a power output mechanism and a reverse gear transmission mechanism;

the high-speed gear transmission mechanism comprises a friction clutch and an elastic element group used for applying pretightening force to the friction clutch, the friction clutch comprises an outer plate flower sleeve, an inner plate spiral roller sleeve, and outer friction plates and inner friction plates which are alternately arranged between the outer plate flower sleeve and the inner plate spiral roller sleeve, each outer friction plate can axially slide along the outer plate flower sleeve, each inner friction plate can axially slide along the inner plate spiral roller sleeve, the inner plate spiral roller sleeve is sleeved on the main shaft and forms a spiral transmission pair with the main shaft, so that the inner plate spiral roller sleeve can axially slide along the main shaft, and the power input mechanism can transmit power to the front and rear gear shifting switching mechanism through the main shaft and the friction clutch in sequence;

the low-speed gear transmission mechanism comprises an auxiliary shaft transmission assembly and an overrunning clutch which is rotatably sleeved on an intermediate cam sleeve, the inner sheet spiral roller way sleeve and an inner core wheel of the overrunning clutch can synchronously rotate through a front-rear gear shifting switching mechanism, the end faces of two ends of the intermediate cam sleeve are respectively matched with the adjacent end face of the inner sheet spiral roller way sleeve and the adjacent end face of a first-stage speed reduction driving gear of the auxiliary shaft transmission assembly to form end face cams, the first-stage speed reduction driving gear is rotatably sleeved on the main shaft, and the power input mechanism can transmit power to the front-rear gear shifting switching mechanism through the main shaft, the inner sheet spiral roller way sleeve, the intermediate cam sleeve, the auxiliary shaft transmission assembly and the overrunning clutch in sequence;

the front and rear gear shifting switching mechanism can be switched, or power is directly transmitted to the tricycle differential mechanism through the power output mechanism, or power is transmitted to the tricycle differential mechanism through the reverse gear transmission mechanism and the power output mechanism in sequence.

By adopting the structure, the tricycle can be self-adaptively matched with the actual running condition and the motor condition according to the resistance condition no matter in forward gear or reverse gear, the tricycle has strong climbing and heavy-load capacity, and meanwhile, the motor is always positioned on a high-efficiency platform, so that the efficiency of the motor under the climbing and heavy-load conditions is greatly improved, the energy consumption of the motor is reduced, and particularly, the forward gear and the reverse gear can be self-adaptively changed with the running resistance to automatically shift gears at high and low speeds under the condition of not cutting off the driving force; and the whole adopts the installation of central drive formula, directly transmits power for differential mechanism, rationally utilizes the chassis space of tricycle, has reduced the assembly degree of difficulty.

Preferably, the method comprises the following steps: the front and rear gear shifting switching mechanism comprises a synchronous sleeve and a gear shifting sleeve, wherein the synchronous sleeve synchronously rotates with the outer sheet flower piece sleeve and the inner core wheel, the gear shifting sleeve is sleeved on the synchronous sleeve in a synchronous rotating mode, and the gear shifting sleeve can slide along the synchronous sleeve to enable the gear shifting sleeve to be connected with a power output mechanism or a reverse gear transmission mechanism. By adopting the structure, the gear shifting device is simple and reliable in structure, stable in gear shifting and easy to operate.

Preferably, the method comprises the following steps: the power output mechanism comprises an output shaft parallel to the main shaft, and an output shaft input gear and an output shaft output gear which are sleeved on the output shaft in a synchronous rotating manner, the output shaft input gear can be meshed with a gear shifting combination gear formed on the gear shifting sleeve, and the output shaft output gear is meshed with a differential mechanism input gear of a tricycle differential mechanism;

the reverse gear transmission mechanism comprises a reverse gear shaft parallel to the main shaft and the output shaft, and a reverse gear input gear and a reverse gear output gear which are sleeved on the reverse gear shaft in a synchronous rotating mode, wherein the reverse gear input gear can be meshed with the gear shifting combination teeth, and the reverse gear output gear is meshed with the output shaft input gear.

By adopting the structure, the front and the back gear shifting and the speed reduction transmission can be stably and reliably completed in a matching mode, and the motor does not need to be reversed when the front and the back gear shifting is performed, so that the structure is more reliable.

Preferably, the method comprises the following steps: the main shaft, the output shaft and the reverse gear shaft are arranged in a triangular shape in space. By adopting the structure, the arrangement is reasonable and the structure is compact.

Preferably, the method comprises the following steps: the outer friction plate and the outer friction plate are sleeved on the power output part and are in spline fit with the power output part, the compression fit part is of a disc structure, and each outer friction plate can axially slide along the inner wall of the power input part;

the inner plate spiral raceway sleeve comprises an inner plate sliding portion in a circular ring structure and a friction plate pressing portion in a circular disc structure, a spiral transmission pair is formed between the inner plate sliding portion and the main shaft, each inner friction plate can slide along the axial direction of the outer wall of the inner plate sliding portion, each outer friction plate and each inner friction plate are located between the pressing fit portion and the friction plate pressing portion, the elastic element group is abutted to the friction plate pressing portion, and the spiral transmission pair is formed between the inner plate sliding portion and the main shaft.

By adopting the structure, the design is ingenious, the assembly is easy, multiple functions can be realized by the inner spiral raceway sleeve and the outer flower sleeve, the number of parts is reduced, the production cost is reduced, and the reliability is improved.

Preferably, the method comprises the following steps: the outer wall of the main shaft is provided with an outer spiral raceway, a plurality of balls are arranged in the outer spiral raceway, the inner wall of the inner sheet spiral raceway sleeve is provided with an inner spiral raceway matched with the outer spiral raceway, and the balls can roll in the outer spiral raceway and the inner spiral raceway. By adopting the structure, the stability of axial sliding fit can be greatly improved.

Preferably, the method comprises the following steps: the auxiliary shaft transmission assembly comprises an auxiliary shaft parallel to the main shaft, and a primary speed reduction driven gear and a secondary speed reduction driving gear which are sleeved on the auxiliary shaft in a synchronous rotating mode, wherein the primary speed reduction driven gear is meshed with the primary speed reduction driving gear, and the secondary speed reduction driving gear is meshed with secondary speed reduction driven teeth of an outer ring of the overrunning clutch. With the above configuration, the reduction gear can be stably and reliably performed.

Preferably, the method comprises the following steps: the rolling bodies distributed along the periphery of each inner core wheel are composed of thick rolling bodies and thin rolling bodies which are alternately arranged, two opposite retainers are arranged on the peripheral surface of each inner core wheel, a circle of annular groove is formed in the inner wall of each retainer, and two ends of each thin rolling body are respectively inserted into the corresponding annular grooves in a sliding mode. By adopting the structure, each thin rolling body can follow up, the overall stability and reliability are improved, and the service life is prolonged.

Preferably, the method comprises the following steps: the power input mechanism comprises a driving motor, an input driving gear and an input driven gear, the input driving gear rotates synchronously with a motor shaft of the driving motor, the input driven gear rotates synchronously with the main shaft, and the input driven gear is meshed with the input driving gear. With the above configuration, the reduction gear can be stably and reliably performed.

Preferably, the method comprises the following steps: the elastic element group is a disc spring sleeved on the main shaft and is arranged between the end face bearing and the inner sheet spiral roller way sleeve. By adopting the structure, the installation of the elastic element group is stably and reliably realized, and the stable pretightening force can be provided for the friction clutch.

Compared with the prior art, the invention has the beneficial effects that:

the tricycle central drive self-adaptive speed change assembly adopting the technical scheme has the advantages that the structure is novel, the design is ingenious, the tricycle can be self-adaptively matched with the actual running condition and the motor condition no matter in forward gear or reverse gear according to the resistance condition, the tricycle has strong climbing and heavy-load capacity, and meanwhile, the motor is always positioned on a high-efficiency platform, so that the efficiency of the motor under the climbing and heavy-load conditions is greatly improved, the energy consumption of the motor is reduced, and particularly, the forward gear and the reverse gear can be self-adaptively changed in high and low speed gear change along with the change of the running resistance under the condition of not cutting off the driving force; and the whole adopts the installation of central drive formula, directly transmits power for differential mechanism, rationally utilizes the chassis space of tricycle, has reduced the assembly degree of difficulty.

Drawings

FIG. 1 is a schematic illustration of a forward gear of the present invention;

FIG. 2 is a schematic illustration of the reverse gear of the present invention;

FIG. 3 is an enlarged view taken at A in FIG. 1;

fig. 4 is an enlarged view at B in fig. 1.

Detailed Description

The present invention will be further described with reference to the following examples and the accompanying drawings.

As shown in fig. 1 and 2, a central driving adaptive speed change assembly of a tricycle mainly comprises a power input mechanism, a main shaft 1, a high-speed gear transmission mechanism, a low-speed gear transmission mechanism, a front-rear gear shifting mechanism, a power output mechanism and a reverse gear transmission mechanism.

Referring to fig. 1-4, the high-speed gear transmission mechanism includes a friction clutch 5 and an elastic element set 3 for applying a pre-tightening force to the friction clutch 5, the friction clutch 5 includes an outer plate spline housing 5a, an inner plate helical raceway housing 5b, and outer friction plates 5c and inner friction plates 5d alternately disposed between the outer plate spline housing 5a and the inner plate helical raceway housing 5b, each outer friction plate 5c is capable of axially sliding along the outer plate spline housing 5a, each inner friction plate 5d is capable of axially sliding along the inner plate helical raceway housing 5b, the inner plate helical raceway housing 5b is sleeved on the main shaft 1, and forms a helical transmission pair with the main shaft 1, so that the inner plate helical raceway housing 5b is capable of axially sliding along the main shaft 1, and the power input mechanism is capable of sequentially transmitting power to the front-rear gear shifting mechanism through the main shaft 1 and the friction clutch 5. Compared with the traditional disc type friction clutch, the friction clutch 5 in the embodiment is used for a long time, the abrasion conditions of the inner friction plates 5d and the outer friction plates 5c are basically consistent, the sliding friction loss is reduced, the abrasion resistance, the stability and the reliability of the friction clutch 5 are improved, and the service life of the friction clutch 5 is prolonged.

The outer friction plate sleeve 5a comprises a power input part 5a1, a press fit part 5a2 and a power output part 5a3 which are sequentially connected, the power input part 5a1 and the power output part 5a3 are both of circular ring structures, the diameter of the power input part 5a1 is larger than that of the power output part 5a3, the synchronous sleeve 11 is sleeved on the power output part 5a3 and is in spline fit with the power output part 5a3, the press fit part 5a2 is of a circular disc structure, and each outer friction plate 5c can axially slide along the inner wall of the power input part 5a 1.

The inner plate spiral raceway sleeve 5b comprises an inner plate sliding portion 5b1 in a circular ring structure and a friction plate pressing portion 5b2 in a circular disc structure, a spiral transmission pair is formed between the inner plate sliding portion 5b1 and the main shaft 1, each inner friction plate 5d can axially slide along the outer wall of the inner plate sliding portion 5b1, each outer friction plate 5c and each inner friction plate 5d are located between the pressing matching portion 5a2 and the friction plate pressing portion 5b2, and the elastic element group 3 is abutted to the friction plate pressing portion 5b 2.

The power input portion 5a1 is spline-engaged with the outer friction plates 5c, and the inner plate sliding portion 5b1 is spline-engaged with the inner friction plates 5 d.

A screw transmission pair is formed between the inner piece sliding part 5b1 and the main shaft 1. Specifically, the outer wall of the main shaft 1 has an outer spiral raceway 1a, a plurality of balls 18 are provided in the outer spiral raceway 1a, and the inner wall of the inner plate spiral raceway sleeve 5b has an inner spiral raceway 5b3 corresponding to the outer spiral raceway 1a, and the balls 18 can roll in the outer spiral raceway 1a and the inner spiral raceway 5b3 to secure stability of axial sliding.

The elastic element group 3 is a disc spring sleeved on the main shaft 1 and is arranged between the end face bearing 22 and the inner sheet spiral roller sleeve 5 b.

Referring to fig. 1-4, the low-speed gear transmission mechanism includes a countershaft transmission assembly and an overrunning clutch 9 rotatably mounted on the intermediate cam sleeve 2, the inner helical raceway sleeve 5b and an inner core wheel 9c of the overrunning clutch 9 can rotate synchronously through the front-rear gear shifting switching mechanism, end faces of two ends of the intermediate cam sleeve 2 respectively form end face cam fit with an adjacent end face of the inner helical raceway sleeve 5b and an adjacent end face of a first-stage reduction driving gear 8 of the countershaft transmission assembly, the first-stage reduction driving gear 8 is rotatably mounted on the main shaft 1, and the power input mechanism can transmit power to the front-rear gear shifting switching mechanism sequentially through the main shaft 1, the inner helical raceway sleeve 5b, the intermediate cam sleeve 2, the countershaft transmission assembly and the overrunning clutch 9.

The auxiliary shaft transmission assembly comprises an auxiliary shaft 4 parallel to the main shaft 1, a first-stage reduction driven gear 6 and a second-stage reduction driving gear 7, wherein the first-stage reduction driven gear 6 and the second-stage reduction driving gear 7 are sleeved on the auxiliary shaft 4 in a synchronous rotating mode, the first-stage reduction driven gear 6 is meshed with a first-stage reduction driving gear 8, and the second-stage reduction driving gear 7 is meshed with a second-stage reduction driven gear 9b of an outer ring 9a of the overrunning clutch.

The rolling bodies distributed along the periphery of each inner core wheel 9c are composed of thick rolling bodies 9d and thin rolling bodies 9e which are alternately arranged, two opposite retainers 9f are arranged on the periphery of the inner core wheel 9c, a circle of annular groove 9f1 is formed in the inner wall of each retainer 9f, and two ends of each thin rolling body 9e are slidably inserted into the corresponding annular grooves 9f1 respectively.

Referring to fig. 1 and 2, the power input mechanism includes a driving motor 19, an input driving gear 20 rotating in synchronization with a motor shaft 19a of the driving motor 19, and an input driven gear 21 rotating in synchronization with the main shaft 1, the input driven gear 21 being engaged with the input driving gear 20.

The front and rear shifting switching mechanism can be switched, or directly transmit power to the tricycle differential 10 through the power output mechanism, or sequentially transmit power to the tricycle differential 10 through the reverse gear transmission mechanism and the power output mechanism.

Specifically, the front-rear shift switching mechanism includes a synchronizing sleeve 11 that rotates synchronously with both the outer disk sleeve 5a and the inner core wheel 9c, and a shift sleeve 12 that is fitted over the synchronizing sleeve 11 so as to rotate synchronously, and the shift sleeve 12 can slide along the synchronizing sleeve 11 so as to be connected to either the power output mechanism or the reverse transmission mechanism.

The power output mechanism comprises an output shaft 13 parallel to the main shaft 1, and an output shaft input gear 14 and an output shaft output gear 15 which are sleeved on the output shaft 13 in a synchronous rotating mode, wherein the output shaft input gear 14 can be meshed with gear shifting combination teeth 12a formed on a gear shifting sleeve 12, and the output shaft output gear 15 is meshed with a differential input gear 10a of a tricycle differential 10.

The reverse gear transmission mechanism comprises a reverse gear shaft 16 parallel to the main shaft 1 and the output shaft 13, and a reverse gear input gear 17 and a reverse gear output gear 18 which are sleeved on the reverse gear shaft 16 in a synchronous rotating mode, wherein the reverse gear input gear 17 can be meshed with the gear shifting combination teeth 12a, and the reverse gear output gear 18 is meshed with the output shaft input gear 14.

Wherein the driving motor 19, the output shaft 13 and the reverse gear shaft 16 are arranged in a triangular shape in space.

The gear shifting sleeve 12 is slid to enable the gear shifting combination teeth 12a to be meshed with the output shaft input gear 14, the elastic element group 3 applies pressure to the inner plate spiral roller way sleeve 5b to press each outer friction plate 5c and each inner friction plate 5d of the friction clutch 5 tightly, at the moment, the friction clutch 5 is in a combination state under the pressure of the elastic element group 3, and power is in a power transmission route of a forward high-speed gear:

the motor 7 → the input drive gear 20 → the input driven gear 21 → the main shaft 1 → the inner disc spiral raceway sleeve 5b → the inner and outer friction discs 5d and 5c → the outer disc spline sleeve 5a → the synchronizer sleeve 11 → the shift sleeve 12 → the output shaft input gear 14 → the output shaft 13 → the output shaft output gear 15 → the tricycle differential 10.

At this time, the elastic element group 3 is not compressed. When the resistance torque transmitted to the friction clutch 5 by the main shaft 1 is larger than or equal to the preset load limit of the friction clutch 5, the inner plate spiral raceway sleeve 5b compresses the elastic element group 3, a gap is formed between each outer friction plate 5c and each inner friction plate 5d of the friction clutch 5, namely, the outer friction plates and the inner friction plates are separated, and the power is transmitted through the following route instead, namely, a forward low-gear power transmission route:

the motor 7 → the input driving gear 20 → the input driven gear 21 → the main shaft 1 → the inner plate spiral raceway sleeve 5b → the intermediate cam sleeve 2 → the primary reduction driving gear 8 → the primary reduction driven gear 6 → the auxiliary shaft 4 → the secondary reduction driving gear 7 → the overrunning clutch 9 → the synchronizer sleeve 11 → the shift sleeve 12 → the output shaft input gear 14 → the output shaft 13 → the output shaft output gear 15 → the tricycle differential 10.

The gear shifting sleeve 12 is slid to enable the gear shifting combination teeth 12a to be meshed with the reverse gear input gear 17, the elastic element group 3 applies pressure to the inner sheet spiral raceway sleeve 5b to press each outer friction sheet 5c and inner friction sheet 5d of the friction clutch 5 tightly, at the moment, the friction clutch 5 is in a combination state under the pressure of the elastic element group 3, and power is in a reverse high-speed gear power transmission route:

the motor 7 → the input drive gear 20 → the input driven gear 21 → the main shaft 1 → the inner disc helical raceway sleeve 5b → the inner and outer friction discs 5d and 5c → the outer disc spline sleeve 5a → the synchronizing sleeve 11 → the shift sleeve 12 → the reverse input gear 17 → the reverse shaft 16 → the reverse output gear 18 → the output shaft input gear 14 → the output shaft 13 → the output shaft output gear 15 → the tricycle differential 10.

At this time, the elastic element group 3 is not compressed. When the resisting moment transmitted to the friction clutch 5 by the main shaft 1 is greater than or equal to the preset load limit of the friction clutch 5, the inner plate spiral raceway sleeve 5b compresses the elastic element group 3, a gap is formed between each outer friction plate 5c and each inner friction plate 5d of the friction clutch 5, namely, the outer friction plates and the inner friction plates are separated, and the power is transmitted through the following route instead, namely, a reverse low-gear power transmission route:

the motor 7 → the input drive gear 20 → the input driven gear 21 → the main shaft 1 → the inner plate spiral raceway sleeve 5b → the intermediate cam sleeve 2 → the primary reduction drive gear 8 → the primary reduction driven gear 6 → the auxiliary shaft 4 → the secondary reduction drive gear 7 → the overrunning clutch 9 → the synchronizer sleeve 11 → the shift sleeve 12 → the reverse input gear 17 → the reverse shaft 16 → the reverse output gear 18 → the output shaft input gear 14 → the output shaft 13 → the output gear 15 → the tricycle differential 10.

Finally, it should be noted that the above-mentioned description is only a preferred embodiment of the present invention, and those skilled in the art can make various similar representations without departing from the spirit and scope of the present invention.