CN113108052A

CN113108052A - Actuator of transfer case

Info

Publication number: CN113108052A
Application number: CN202110367241.XA
Authority: CN
Inventors: 张浩源; 杨晓龙; 纪晓辉
Original assignee: Honeycomb Transmission Technology Hebei Co Ltd
Current assignee: Honeycomb Transmission Technology Hebei Co Ltd
Priority date: 2021-04-06
Filing date: 2021-04-06
Publication date: 2021-07-13
Anticipated expiration: 2041-04-06
Also published as: CN113108052B

Abstract

The invention relates to the technical field of transfer cases, and provides an actuating mechanism of a transfer case. The gear shifting shaft assembly comprises a gear shifting shaft, a gear post, a spring baffle and a spring seat, wherein the gear post and the spring baffle are fixedly arranged on the gear shifting shaft, the spring seat is sleeved on the gear shifting shaft, the gear shifting shaft is in transmission connection with a gear shifting motor, a rotating hub is sleeved on the gear shifting shaft and is provided with a gear type line groove, the gear post is arranged in the gear type line groove in a penetrating mode to drive the rotating hub to move axially, and a shifting fork fixedly connected with the rotating hub realizes switching of high and low gear positions along with the axial movement of the; the driving gear of the cam mechanism is fixedly arranged on the gear shifting shaft and is in transmission connection with the cam disc assembly, and the driving gear drives the cam disc assembly to control the engagement degree of the clutch assembly so as to control the torque distribution between the front output shaft and the rear output shaft and lock the front output shaft and the rear output shaft. The actuator of the transfer case controls the high-low gear shift and the torque adjustment of the clutch through a single system.

Description

Actuator of transfer case

Technical Field

The invention relates to the technical field of transfer cases, in particular to an actuating mechanism of a transfer case.

Background

With the increasing requirements of consumers on the automobile handling performance and the off-road performance, the automobile industry is rapidly developed, and the four-wheel drive technology of the vehicle is continuously improved. At present, vehicles of high-end vehicles and vehicles with off-road requirements all adopt a four-wheel drive structure, so that power output by a transmission is distributed to a front axle and a rear axle according to a required proportion through a transfer case, four wheels and the ground have driving force, and the control performance and the passing performance of the vehicles are improved.

In an existing vehicle transmission system, a transfer case is generally used for achieving high-low gear switching and a torque adjusting function of a clutch, however, the high-low gear switching function and the torque adjusting function of the clutch need to be achieved through different systems respectively, some of the different systems are controlled by a plurality of motors respectively, and some of the different systems are controlled by the motors and an electromagnetic mechanism which are used simultaneously, so that the number of parts is increased, and the cost is high.

Therefore, how to realize two functions of shifting between high and low gears and adjusting the torque of the clutch through one system is a problem to be solved urgently by those skilled in the art.

Disclosure of Invention

In view of this, the present invention is directed to an actuator of a transfer case, which can utilize a motor to drive a set of systems to achieve high-low gear shifting and torque adjustment of a clutch.

In order to achieve the purpose, the technical scheme of the invention is realized as follows:

an actuating mechanism of a transfer case comprises a gear shifting motor; the gear shifting shaft assembly comprises a gear shifting shaft, a retaining column and a spring baffle which are fixedly arranged on the gear shifting shaft, and a spring seat which is sleeved on the gear shifting shaft, and the gear shifting shaft is connected with the output end of the gear shifting motor;

the shifting device comprises a rotating hub, a shifting shaft and a blocking column, wherein a gear type groove is formed in the rotating hub, the rotating hub is sleeved on the shifting shaft, the blocking column penetrates through the gear type groove, the blocking column moves in the gear type groove to drive the rotating hub to move in parallel with the shifting shaft in the axial direction, a shifting fork is fixedly connected to the rotating hub, and the shifting fork moves along with the rotating hub to realize high-low gear switching;

the elastic piece comprises a first elastic piece and a second elastic piece, the first elastic piece is sleeved on the gear shifting shaft, and two ends of the first elastic piece respectively abut against the rotating hub and the spring baffle; the second elastic piece is sleeved on the gear shifting shaft, and two ends of the second elastic piece respectively abut against the spring seat and the shifting fork;

the cam mechanism comprises a driving gear and a cam disc component, the driving gear is fixedly arranged on the gear shifting shaft and is in transmission connection with the cam disc component, and the driving gear drives the cam disc component to control the engagement degree of the clutch assembly so as to control the torque distribution between the front output shaft and the rear output shaft and lock the front output shaft and the rear output shaft.

Further, the gear shifting shaft assembly further comprises a clamping ring, and the clamping ring is clamped on the gear shifting shaft and acts on one side, far away from the second elastic piece, of the spring seat.

Furthermore, one end of the stop column is fixedly connected with the gear shifting shaft, the end part of the other end of the stop column is provided with a rolling sleeve, and the rolling sleeve and the stop column can rotate relatively and are matched with the gear molded line groove.

Furthermore, the hub with two connection faces of shift fork are located and are had first spline groove and second spline groove respectively, first spline groove with second spline groove staggered arrangement, and follow first spline groove with offer the snap ring groove on the periphery of second spline groove, the snap ring card cover is in be used for in the snap ring groove with the shift fork with hub fixed connection.

Further, the cam disc subassembly includes ring gear, last protruding rim plate and the lower rim plate that the coaxial line was arranged, drive gear with the ring gear transmission is connected, lower protruding rim plate with match a clearance fit and with the casing fixed connection of transfer case, last protruding rim plate cover be in the outside of lower protruding rim plate, the duplex winding the axis is rotatory, the ring gear cover is in the periphery of last protruding rim plate, and promote it is rotatory to go up the protruding rim plate.

Furthermore, a first central through hole and a protruding part coaxial with the first central through hole are formed in the lower convex wheel disc, a second central through hole is formed in the upper convex wheel disc, a first limiting column and a second limiting column are arranged on two symmetrical sides of the upper convex wheel disc, a first protrusion and a second protrusion along the axis direction are arranged on two symmetrical sides of the ring gear, the second central through hole penetrates through the protruding part, and the first limiting column and the second limiting column correspondingly abut against different sides of the first protrusion and the second protrusion;

the upper convex wheel disc and the lower convex wheel disc are adjacent to each other in surface, a plurality of grooves are formed in the adjacent surfaces of the upper convex wheel disc and the lower convex wheel disc, the grooves are bidirectional depth gradually changing grooves, the grooves are arranged around the rotating center of the upper convex wheel disc, a plurality of balls are arranged between the upper convex wheel disc and the lower convex wheel disc, and the balls are respectively located in the corresponding grooves.

Furthermore, a damping spring is arranged between the ring gear and the lower convex wheel disc and used for buffering vibration between the ring gear and the lower convex wheel disc.

Further, the shifting fork is nested in the high-low gear sleeve, and the high-low gear sleeve is driven to move axially parallel to the gear shifting shaft to realize the switching of high gear or low gear.

Further, the first elastic member and the second elastic member are springs.

Further, gear motor corotation or reversal, gear type line recess includes that high gear is regional, neutral region and low gear is regional, during gear motor corotation the shift fork is in high gear is regional, cam mechanism compresses tightly the clutch assembly, during gear motor reversal, the shift fork is followed high gear is regional through the neutral region passes through to the low gear is regional, cam mechanism compresses tightly after rotatory the clutch assembly.

Compared with the prior art, the actuating mechanism of the transfer case has the following advantages:

in the transfer case executing mechanism, the gear shifting motor drives the gear shifting shaft to rotate, and the driving gear drives the cam disc component to move in the axial direction of the gear shifting shaft under the driving of the gear shifting shaft so as to press the clutch assembly, so that the torque distribution between the rear output shaft and the front output shaft is realized; meanwhile, the shift post moves in the shift molded line groove under the driving of the shift shaft to drive the rotating hub to axially move parallel to the shift shaft, so that the shifting fork is driven to axially move, and the switching between a high gear and a low gear is realized; and under a low gear, the clutch is compressed to realize the locking of the front output shaft and the rear output shaft. Therefore, the high-low gear switching and locking functions and the torque distribution of the clutch can be controlled by one system of the executing mechanism, so that the number of parts is reduced, the weight is reduced, the cost is reduced, and the structure is simplified.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic structural diagram of an actuator of a transfer case according to an embodiment of the present invention;

fig. 2 is a schematic perspective view of an actuator of a transfer case according to an embodiment of the present invention;

FIG. 3 is a schematic structural view of a cam plate assembly according to an embodiment of the present invention;

fig. 4 is a schematic view of a connecting structure of the shift shaft and the shift post according to the embodiment of the present invention;

FIG. 5 is a schematic view of a connection structure of a shift fork and a hub according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of the working principle of the hub gear profile and the clutch assembly according to the embodiment of the invention.

Description of reference numerals:

1 gear motor 2 gear shift axle 21 bumping post

22 spring baffle 23 spring seat 24 snap ring

25 roller 3 hub 31 gear type line groove

311 high gear region 312 neutral region 313 high gear region

32 first spline groove 4 Shift fork 41 second spline groove

5 first elastic member 6 second elastic member 7 cam mechanism

71 drive gear 72 and cam disk on ring gear 73

74 lower cam disk 75 first central through hole 76 projection

77 second center through hole 78 first limit post 79 second limit post

80 first projection 81 second projection 82 groove

83 ball 84 damping spring 9 high-low gear sleeve

Detailed Description

In addition, the embodiments of the present invention and the features of the embodiments may be combined with each other without conflict.

The present invention will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

Fig. 1 and fig. 2 are schematic structural diagrams of an actuator of a transfer case according to an embodiment of the present invention. Referring to fig. 1 and 2, an actuator of a transfer case according to a basic embodiment of the present invention includes a shift motor 1, a shift shaft assembly, a rotary hub 3, an elastic member, and a cam mechanism 7. The gear shifting shaft assembly comprises a gear shifting shaft 2, a stop column 21 and a spring baffle 22 which are fixedly arranged on the gear shifting shaft 2, and a spring seat 23 which is sleeved on the gear shifting shaft 2, wherein the gear shifting shaft 2 is connected with the output end of the gear shifting motor 1; a gear type groove 31 is formed in the rotating hub 3, the rotating hub 3 is sleeved on the gear shifting shaft 2, the retaining column 21 penetrates through the gear type groove 31, the retaining column 21 moves in the gear type groove 31 to drive the rotating hub 3 to move in parallel with the gear shifting shaft 2 in the axial direction, a shifting fork 4 is fixedly connected to the rotating hub 3, and the shifting fork 4 moves along with the rotating hub 3 to realize high-low gear switching; the elastic parts comprise a first elastic part 5 and a second elastic part 6, the first elastic part 5 is sleeved on the gear shifting shaft 2, and two ends of the first elastic part respectively abut against the rotary hub 3 and the spring baffle 22; the second elastic piece 6 is sleeved on the gear shifting shaft 2, and two ends of the second elastic piece respectively abut against the spring seat 23 and the shifting fork 4; the cam mechanism 7 comprises a driving gear 71 and a cam disc assembly, the driving gear 71 is fixedly arranged on the gear shifting shaft 2 and is in transmission connection with the cam disc assembly, and the driving gear 71 drives the cam disc assembly to control the engagement degree of the clutch assembly so as to control the torque distribution between the front output shaft and the rear output shaft and lock the front output shaft and the rear output shaft.

As a specific embodiment of the present invention, the shift shaft assembly further comprises a snap ring 24, and the snap ring 24 is snap-fitted on the shift shaft 2 and acts on a side of the spring seat 23 away from the second elastic member 6. One side of the spring seat 23 is retained by a snap ring 24, so that the spring seat 23 can move axially parallel to the shift shaft 2 in a limited stroke.

More specifically, one end of the shift post 21 is fixedly connected with the shift shaft 2, and the end of the other end is provided with a roller 25, and the roller 25 and the shift post 21 can rotate relatively and are matched with the gear type line groove 31. As shown in fig. 4, the connection between the shift post 21 and the shift shaft 2 can be realized by forming a through hole on the shift shaft 2 for engaging with the shift post 21, wherein one end of the shift post 21 passes through the through hole, correspondingly forming an annular groove on the circumferential surface of the bottom end of the through hole where the shift post 21 passes through the through hole, wherein the annular groove is provided with a clamping ring for limiting one end of the shift post, and a flange is arranged on the circumferential surface of the shift post at the position where the shift post 21 engages with the upper surface of the shift shaft 2 for limiting the other end of the shift post; or an annular groove is also formed at the matching part of the stop post 21 and the upper surface of the gear shifting shaft 2 along the circumferential surface of the stop post, and the clamping ring is clamped in the annular groove to limit the other end of the stop post. The engagement of the uppermost end of the abutment 21 with the gear type recess 31 is provided with a roller 25, which roller 25 may be a bearing and a relative rotation between the abutment 21, so that the abutment 21 moves in the gear type recess 31 reducing the friction between the engagement surfaces of the abutment 21 and the gear type recess 31.

More specifically, as shown in fig. 5, a first spline groove 32 and a second spline groove 41 are respectively formed in the connecting surface of the hub 3 and the connecting surface of the shift fork 4 at the connecting surface of the hub 3 and the shift fork 4, the two spline grooves are engaged in a staggered manner, a snap ring groove is formed in the circumference of the side surface of each spline groove, and the snap ring is fixedly connected with the shift fork 4 and the hub 3 in the snap ring groove, so that the shift fork 4 moves axially along with the hub 3, and switching between a high gear and a low gear is realized.

As a more specific embodiment of the present invention, as shown in fig. 3, the cam disc assembly includes a ring gear 72, an upper cam disc 73 and a lower cam disc 74, which are coaxially arranged, the driving gear 71 is in transmission connection with the ring gear 72, the lower cam disc 74 is in clearance fit with a matching shaft (which may be a rear output shaft or an input shaft of a transfer case) and is fixedly connected with a casing of the transfer case, the upper cam disc 73 is sleeved on the outer side of the lower cam disc 74 and rotates around the axis, and the ring gear 72 is sleeved on the outer periphery of the upper cam disc 73 and pushes the upper cam disc 73 to rotate.

More specifically, the lower cam disc 74 is formed with a first central through hole 75 and a protruding portion 76 coaxial with the first central through hole 75, the upper cam disc 73 is formed with a second central through hole 77, two symmetrical sides of the upper cam disc 73 are provided with a first limiting column 78 and a second limiting column 79, two symmetrical sides of the ring gear 72 are provided with a first protrusion 80 and a second protrusion 81 along the axial direction, the second central through hole 77 penetrates through the protruding portion 76, and the first limiting column 78 and the second limiting column 79 correspondingly abut against different sides of the first protrusion 80 and the second protrusion 81; a plurality of grooves 82 are formed on the adjacent surfaces of the upper cam disc 73 and the lower cam disc 74, the grooves 82 are bidirectional depth gradient type grooves, the grooves are arranged around the rotation center of the upper cam disc 73, a plurality of balls 83 are arranged between the upper cam disc 73 and the lower cam disc 74, and the balls 83 are respectively positioned in the corresponding grooves 82.

The cam disc assembly provided by the embodiment of the invention acts on the clutch assembly under the driving of the driving gear, when the cam disc assembly is required to press the clutch assembly, the driving gear 71 drives the ring gear 72 of the cam disc assembly to rotate, the first protrusion 80 and the second protrusion 81 on the ring gear 72 are positioned on the opposite sides of the first limiting column 78 and the second limiting column 79 on the symmetrical two sides of the upper cam disc 73, so that when the ring gear 72 rotates, the first protrusion 80 and the second protrusion 81 can push the first limiting column 78 and the second limiting column 79 to make the upper cam disc 73 rotate around the bulge 76 of the lower cam disc 74, because a plurality of grooves 82 with gradually changing depth in two directions are correspondingly arranged on the two adjacent surfaces of the upper cam disc 73 and the lower cam disc 74, namely the middle position of the groove 82 is the lowest point of the groove, the depth gradually becomes shallower from the middle position to the two ends, a ball 83 is arranged in each corresponding groove 82, the balls 83 are initially at the lowest point of the grooves 82, and as the ring gear 72 pushes the upper cam plate 73 to rotate, the balls 83 roll within the grooves 82, causing the balls 83 to move from a deeper position to a shallower position or from a shallower position to a deeper position within the grooves 82, thereby increasing or decreasing the distance between the upper cam plate 73 and the lower cam plate 74, i.e., causing the upper cam plate 73 to move axially on the mating shaft (rear output shaft or input shaft of the transfer case), the upper cam plate 73 being connected to the clutch assembly, and the upper cam plate 73, when moved axially, pressing or releasing the clutch assembly.

In order to reduce the impact of the electronic control gear shifting system on the cam mechanism 7, a damping spring 84 is arranged between the ring gear 72 and the lower cam disc 74, so that the working performance of the cam mechanism 7 is improved, and the NVH performance of the vehicle is improved.

According to the transfer case actuating mechanism provided by the embodiment of the invention, the shifting fork 4 is nested in the high-low gear sleeve 9, and the high-low gear sleeve 9 is driven to move parallel to the axial direction of the gear shifting shaft 2 to realize the switching of high gear or low gear.

More preferably, the first elastic member 5 and the second elastic member 6 are springs. The first elastic member 5 is used for returning in the two-drive high-speed mode, and the second elastic member 6 is used for returning in the four-drive low-speed mode.

More specifically, in the transfer case actuator provided by the embodiment of the present invention, the shift motor 1 can rotate forward or backward, and the rotating hub 3 and the cam disc assembly are driven to move under the forward or backward rotation state of the shift motor 1, so as to implement high-low gear switching and two-drive and four-drive switching. As shown in fig. 6, the gear type groove 31 includes a high gear area 311, a neutral area 312 and a low gear area 313, when the shift motor 1 rotates forward, the shift post 21 always moves in the high gear area 311, so that the high-low gear sleeve 9 engaged with the shift fork 4 is in the high gear of the transfer case, and the cam disc component gradually presses the clutch assembly under the action of the driving gear 71, so that the vehicle is switched from the two-drive mode to the four-drive mode; when the gear shifting motor 1 rotates reversely, the shift post 21 moves from a high gear area to a low gear area through a neutral area of the gear molded line groove 31, so that the rotating hub 3 moves axially along the gear shifting shaft 2, and then the high-low gear sleeve matched with the shifting fork 4 is driven to shift from a high gear position to a low gear position, and switching between the high gear position and the low gear position is realized. Meanwhile, the cam disc assembly idles for a certain distance under the action of the driving gear 71 (the idling distance corresponds to the situation that the shifting fork enters a neutral gear area from a high gear area), and then the clutch assembly is gradually pressed, so that the vehicle is switched from a two-drive mode to a four-drive mode.

The specific operation of the actuator of the transfer case according to the present invention is described in detail below with reference to fig. 1 to 6: when the vehicle enters a four-wheel drive high speed (4H) mode from the two-wheel drive high speed (2H) mode, the gear shifting motor 1 rotates forward to drive the gear shifting shaft 2 to rotate, the driving gear 71 drives the ring gear 72 to rotate under the rotation of the gear shifting shaft 2, and as the first protrusion 80 and the second protrusion 81 of the ring gear 72 respectively abut against the opposite sides of the first limiting column 78 and the second limiting column 79 of the upper cam disc 73, the ring gear 72 pushes the upper cam disc 73 to rotate relative to the lower cam disc 74 to generate axial movement to press a clutch assembly connected with the upper cam disc 73 when rotating, and the clutch assembly is connected with a chain wheel arranged on a rear output shaft, so that the four-wheel drive mode is realized by transmitting power to the chain wheel of a front output shaft through the chain wheel on the rear output shaft; at this time, the shift post 21 always moves in the high range region 311 of the hub gear profile groove 31, and high and low ranges are not switched, and the state is a four-wheel drive high-speed mode; when the vehicle enters a four-wheel drive low-speed (4L) mode from a four-wheel drive high-speed (4H) mode, the gear shifting motor 1 rotates reversely, the gear post 21 moves to a low gear area 313 of the gear type groove 31 along with the rotation of the gear shifting shaft 2 to drive the rotating hub 3 to move axially, and meanwhile, the shifting fork 4 enables the high-low gear sleeve 9 to be meshed with a low gear of a high-low gear mechanism of the transfer case under the axial movement of the rotating hub 3, so that the switching between the high gear and the low gear is realized; when the gear shifting motor 1 rotates reversely, the driving gear 71 drives the ring gear 72 to rotate under the rotation of the gear shifting shaft 2, after the ring gear 72 rotates a certain distance on the outer side of the upper cam disc 73, the first protrusion 80 and the second protrusion 81 of the ring gear 72 abut against the first limiting column 78 and the second limiting column 79 of the upper cam disc 73 again, the first limiting column 78 and the second limiting column 79 are pushed to enable the upper cam disc 73 to rotate relative to the lower cam disc 74 to generate axial movement so as to press a clutch assembly connected with the upper cam disc 73, and the power output from the rear is transmitted to the front output shaft. When the vehicle needs large torque, the vehicle is in a four-wheel drive low speed (4L), the clutch is continuously pressed, and the rear output shaft and the front output shaft of the divider are locked.

Therefore, the actuating mechanism of the transfer case can respectively control high-low gear switching, low-speed locking and torque distribution of the clutch of the vehicle, has a simple structure, is convenient to assemble, reduces the number and weight of parts and reduces the cost; the structural arrangement is compact.

The present invention is not limited to the above preferred embodiments, and any modifications, equivalent substitutions, improvements, etc. within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An actuator for a transfer case, comprising:

a shift motor (1);

the gear shifting shaft assembly comprises a gear shifting shaft (2), a retaining column (21) and a spring baffle (22) which are fixedly arranged on the gear shifting shaft (2), and a spring seat (23) sleeved on the gear shifting shaft (2), and the gear shifting shaft (2) is connected with the output end of the gear shifting motor (1);

the gear shifting mechanism comprises a rotating hub (3), a gear type line groove (31) is formed in the rotating hub (3), the rotating hub (3) is sleeved on the gear shifting shaft (2), a blocking column (21) penetrates through the gear type line groove (31), the blocking column (21) moves in the gear type line groove (31) to drive the rotating hub (3) to move in parallel with the gear shifting shaft (2) in the axial direction, a shifting fork (4) is fixedly connected to the rotating hub (3), and the shifting fork (4) moves along with the rotating hub (3) to realize high-low gear switching;

the elastic piece comprises a first elastic piece (5) and a second elastic piece (6), the first elastic piece (5) is sleeved on the gear shifting shaft (2), and two ends of the first elastic piece respectively abut against the rotary hub (3) and the spring baffle (22); the second elastic piece (6) is sleeved on the gear shifting shaft (2), and two ends of the second elastic piece respectively abut against the spring seat (23) and the shifting fork (4);

the gear shifting mechanism comprises a cam mechanism (7), the cam mechanism (7) comprises a driving gear (71) and a cam disc component, the driving gear (71) is fixedly arranged on the gear shifting shaft (2) and is in transmission connection with the cam disc component, and the driving gear (71) drives the cam disc component to control the engagement degree of the clutch assembly so as to control the torque distribution between the front output shaft and the rear output shaft and lock the front output shaft and the rear output shaft.

2. An actuator of a transfer case according to claim 1, characterized in that the shift shaft assembly further comprises a snap ring (24), the snap ring (24) is snap fitted on the shift shaft (2) and acts on a side of the spring seat (23) away from the second elastic member (6).

3. Actuator of a transfer gear according to claim 2, characterized in that one end of the shift post (21) is fixedly connected to the shift shaft (2) and the other end is provided with a roller (25), and the roller (25) and the shift post (21) are relatively rotatable and are engaged with the gear profile groove (31).

4. The actuator of the transfer case according to claim 1, wherein the two connecting surfaces of the hub (3) and the fork (4) are respectively provided with a first spline groove (32) and a second spline groove (41), the first spline groove (32) and the second spline groove (41) are arranged in a staggered manner, and a snap ring groove is formed along the circumferential surfaces of the first spline groove (32) and the second spline groove (41), and a snap ring is snapped in the snap ring groove to fixedly connect the fork and the hub.

5. The actuator of the transfer case of any one of claims 1 to 4, wherein the cam disc assembly comprises a ring gear (72), an upper cam disc (73) and a lower cam disc (74) which are coaxially arranged, the driving gear (71) is in transmission connection with the ring gear (72), the lower cam disc (74) is in clearance fit with a matching shaft and is fixedly connected with a shell of the transfer case, the upper cam disc (73) is sleeved on the outer side of the lower cam disc (74) and rotates around the axis, and the ring gear (72) is sleeved on the outer periphery of the upper cam disc (73) and pushes the upper cam disc (73) to rotate.

6. The actuator of the transfer case according to claim 5, wherein the lower cam disc (74) is formed with a first central through hole (75) and a bulge (76) coaxial with the first central through hole (75), the upper cam disc (73) is formed with a second central through hole (77), two symmetrical sides of the upper cam disc (73) are provided with a first limit post (78) and a second limit post (79), two symmetrical sides of the ring gear (72) are provided with a first protrusion (80) and a second protrusion (81) along the axial direction, the second central through hole (77) passes through the bulge (76), and the first limit post (78) and the second limit post (79) correspondingly abut against opposite sides of the first protrusion (80) and the second protrusion (81);

the upper convex wheel disc (73) and the lower convex wheel disc (74) are adjacent in surface and are all formed with a plurality of grooves (82), the grooves (82) are bidirectional depth gradient grooves, the grooves (82) are arranged around the rotating center of the upper convex wheel disc (73), a plurality of balls (83) are arranged between the upper convex wheel disc (73) and the lower convex wheel disc (74), and the balls (83) are respectively located in the corresponding grooves (82).

7. The actuator of the transfer case of claim 6, wherein a damping spring (84) is disposed between the ring gear (72) and the lower cam disc (74) for damping vibration between the ring gear (72) and the lower cam disc (74).

8. The actuator of a transfer case according to claim 7, characterized in that the shift fork (4) is nested in a high-low gear sleeve (9), and the high-low gear sleeve (9) is driven to move axially parallel to the gear shifting shaft (2) to realize the switching of high gear or low gear.

9. Actuator according to claim 8, wherein said first (5) and second (6) elastic members are springs.

10. A transfer case actuator according to claim 1, wherein the shift motor (1) can rotate in forward or reverse direction, the gear profile recess (31) comprises a high gear area (311), a neutral area (312) and a low gear area (313), the shift fork (4) is located in the high gear area (311) when the shift motor (1) rotates in forward direction, the cam mechanism compresses the clutch assembly, the shift fork (4) transitions from the high gear area (311) to the low gear area (313) through the neutral area (312) when the shift motor (1) rotates in reverse direction, and the cam mechanism compresses the clutch assembly after rotating.