A full-time transfer case

Abstract

The present invention discloses a full-time transfer case. Compared with traditional transfer cases, it has a richer variety of working gear positions, can achieve more functions, and is equipped with an oil pump driven by a power input shaft, which can provide better lubrication and cooling effects for the structures at relatively higher positions inside the transfer case housing. The main structures of this application include a transfer case housing, an oil pump, a power input shaft, an input sun gear, an input sun gear hub, several input planetary gears, an input planetary carrier, an input planetary gear hub, an input ring gear, a rear output shaft, a rear output gear hub, a high / low speed shift sleeve, a high / low speed shift fork, a shift guide shaft, a front output shaft, a driving sprocket, a driven sprocket, a transmission chain, and a magnet block. An axial oil passage and oil supply holes are provided on the rear output shaft, and it also includes a differential housing, a differential planetary carrier, a differential sun gear, a differential ring gear, a mating gear hub, differential planetary gears, a differential shift sleeve, a differential shift fork, and a sprocket hub.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle transmission and transfer case, and particularly relates to a full-time transfer case. Background Art

[0002] On a multi-axle drive vehicle, in order to distribute the power output from the transmission to each drive axle, a transfer case is generally installed. The basic structure of the transfer case is also a gear transmission system. Its input shaft is directly or connected to the second shaft of the transmission through a universal transmission device, and its output shaft has several, which are respectively connected to each drive axle through a universal transmission device. For a two-axle vehicle, the working gears of a traditional transfer case mainly include 2H (two-wheel drive high speed) gear, 4H (four-wheel drive high speed) gear, and 4L (four-wheel drive low speed) gear. Summary of the Invention

[0003] The present invention provides a full-time transfer case, which has working gears such as two-wheel drive high speed gear, four-wheel drive high speed torque automatic distribution gear, four-wheel drive high speed torque ratio constant gear, and four-wheel drive low speed torque ratio constant gear. Compared with the traditional transfer case, the types of working gears are more abundant, more functions can be realized, and an oil pump driven by the power input shaft is configured, which can provide better lubrication and cooling and heat dissipation effects for the structures at relatively high positions inside the transfer case housing.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A full-time transfer case includes a transfer case housing, an oil pump, a power input shaft, an input sun gear, an input sun gear hub, a plurality of input planetary gears, an input planetary carrier, an input planetary gear hub, an input ring gear, a rear output shaft, a rear output gear hub, a high and low speed shift sleeve, a high and low speed shift fork, a shift guide shaft, a front output shaft, a driving sprocket, a driven sprocket, a transmission chain, and a magnet block. The oil pump is driven by the power input shaft. An axial oil passage supplied with oil by the oil pump and a plurality of oil supply holes communicating with the axial oil passage are provided on the rear output shaft;

[0006] It further includes a differential housing with one end open, a differential planetary carrier rotatably connected to the driving sprocket, a differential sun gear capable of driving the driving sprocket, a differential ring gear located inside the differential housing, a mating gear hub located inside the differential housing, and a plurality of differential planetary gears meshing with the differential ring gear. The differential housing is rotatably connected to the rear output shaft. The differential planetary carrier is relatively fixed to the differential housing. The differential ring gear drives the rear output shaft through the mating gear hub. The differential planetary gears mesh with the differential sun gear. A planetary gear shaft rotatably mating with the planetary carrier is provided on the differential planetary gears. A front side gear hub of the housing and a rear side gear hub of the housing are provided on the differential housing. The input sun gear hub, the input planetary gear hub, the rear output gear hub, and the front side gear hub of the housing are all adapted to the high and low speed shift sleeve;

[0007] It also includes a differential shift gear sleeve, a differential shift fork, and a sprocket hub capable of driving the driving sprocket to rotate. The open end of the differential housing faces the sprocket hub, and there is a separation gap between the open end of the differential housing and the sprocket hub. Both the rear-side hub of the housing and the sprocket hub are adapted to the differential shift gear sleeve.

[0008] Preferably, an oil extraction port is provided at the bottom of the transfer case housing. A filter screen is provided at the oil extraction port. The magnet block is beside the oil extraction port. The liquid inlet end of the oil pump is connected to the oil extraction port through a tubing. An inner shaft hole is provided on the power input shaft. A shaft sleeve rotatably and sealingly fitted with the inner shaft hole is sleeved on the rear output shaft. A bowl-shaped oil blocking plug piece is provided in the inner shaft hole. The inner shaft hole wall, the shaft sleeve, the outer side wall of the rear output shaft, and the bowl-shaped oil blocking plug piece jointly enclose an oil inlet cavity. The oil shaft passage communicates with the oil inlet cavity. The liquid outlet end of the oil pump communicates with the oil inlet cavity.

[0009] Preferably, it also includes a shift motor, a shift rotating shaft driven by the shift motor, and a shift cam provided on the shift rotating shaft. The high-low speed shift fork includes a high-low speed fork head, and the differential shift fork includes a differential fork head. The shift cam is provided with a first circumferential flat groove, a first spiral inclined guide groove, a second circumferential flat groove, a second spiral inclined guide groove, and a third circumferential flat groove that are adapted to the high-low speed fork head and are continuously arranged. The shift cam is provided with a first flat contact end face, a spiral inclined face, and a second flat contact end face that are adapted to the differential fork head and are continuously arranged. The differential shift gear sleeve is always combined with the rear-side hub of the housing. A return spring for pressing the differential fork head on the first flat contact end face, the spiral inclined face, or the second flat contact end face is provided on the shift guide shaft;

[0010] When the high-low speed fork head is in the first circumferential flat groove and the differential fork head is pressed on the first flat contact end face: the high-low speed shift gear sleeve is combined with the input sun gear hub, the high-low speed shift gear sleeve is combined with the rear output gear hub, and the differential shift gear sleeve is separated from the sprocket hub;

[0011] When the high-low speed fork head is in the second circumferential flat groove and the differential fork head is pressed on the first flat contact end face: the high-low speed shift gear sleeve is combined with the input sun gear hub, the high-low speed shift gear sleeve is combined with the front-side hub of the housing, and the differential shift gear sleeve is separated from the sprocket hub;

[0012] When the high-low speed fork head is in the second circumferential flat groove and the differential fork head is pressed on the second flat contact end face: the high-low speed shift gear sleeve is combined with the input sun gear hub, the high-low speed shift gear sleeve is combined with the front-side hub of the housing, and the differential shift gear sleeve is combined with the sprocket hub;

[0013] When the high-low speed fork head is in the third circumferential flat groove and the differential fork head is pressed on the second flat contact end face: the high-low speed shift gear sleeve is combined with the input planetary gear hub, the high-low speed shift gear sleeve is combined with the front-side hub of the housing, and the differential shift gear sleeve is combined with the sprocket hub.

[0014] Preferably, the output end of the shift motor drives a shift rotating shaft through a coil spring. The coil spring is sleeved on the shift rotating shaft. One end of the coil spring is fixedly connected to the output end of the shift motor, and the other end of the coil spring is fixedly connected to the shift rotating shaft.

[0015] Preferably, the driving sprocket, the shift rotating shaft and the driven sprocket are arranged in sequence from top to bottom, and the input sun gear hub, the rear output gear hub, the input planetary gear hub, the front side gear hub of the housing, the rear side gear hub of the housing, the sprocket gear hub and the transmission chain are arranged in sequence along the axial direction of the power input shaft.

[0016] Preferably, a first needle bearing, a second needle bearing and a terminal ball bearing are arranged on the rear output shaft. The first needle bearing is matched with the rear output shaft, the second needle bearing is matched with the rear output shaft, and the terminal ball bearing is matched with the rear output shaft. The first needle bearing is matched with the driving sprocket, the second needle bearing is matched with the driving sprocket, and the terminal ball bearing is matched with the transfer case housing. The number of oil supply small holes is three, and the three oil supply small holes are arranged in sequence along the axial direction of the rear output shaft. Among the three oil supply small holes: the oil supply small hole adjacent to the power input shaft has an outlet facing the first needle bearing, the oil supply small hole far from the power input shaft has an outlet facing the terminal ball bearing, and the remaining oil supply small hole has an outlet facing the second needle bearing.

[0017] Preferably, the mating gear hub includes a gear hub body and a gear hub extension section. The differential ring gear includes a ring gear body and a ring gear hub. The gear hub body is slidably connected to the ring gear hub, the gear hub body is slidably connected to the rear output shaft, the differential sun gear is slidably connected to the driving sprocket, the planetary gear shaft is slidably matched with the differential planet carrier. The differential ring gear is a helical ring gear, the differential planetary gear is a helical gear, and the differential sun gear is a helical gear. A housing limit projection is arranged on the differential housing, and a planet carrier limit projection is arranged on the differential planet carrier. A first clutch plate ring sleeved on the housing limit projection, a second clutch plate ring sleeved on the gear hub extension section, a third clutch plate ring sleeved on the driving sprocket and a fourth clutch plate ring sleeved outside the planet carrier limit projection are arranged in the differential housing. The differential housing has a housing friction surface for contacting the first clutch plate ring. The housing friction surface, the first clutch plate ring, the ring gear hub, the fourth clutch plate ring, the differential planetary gear and the third clutch plate ring are arranged in sequence along the axial direction of the rear output shaft. The differential planet carrier has a planet carrier friction surface for contacting the third clutch plate ring. The housing friction surface, the first clutch plate ring, the gear hub body, the second clutch plate ring, the differential sun gear, the third clutch plate ring and the planet carrier friction surface are arranged in sequence along the axial direction of the rear output shaft.

[0018] Preferably, the differential housing is rotatably connected to the rear output shaft through a housing needle bearing, and the differential planet carrier is rotatably connected to the driving sprocket through a planet carrier needle bearing. The rear output shaft includes a contracted journal section. The first needle bearing, the second needle bearing, the outer side wall of the contracted journal section, and the inner side wall of the driving sprocket jointly enclose an oil storage cavity. The power input shaft is provided with a large oil supply hole communicating with the shaft oil passage, the large oil supply hole communicates with the oil storage cavity, the sprocket hub is provided with a main oil passage inside the hub, a plurality of hub oil inlet passages communicating with the main oil passage inside the hub, and a plurality of hub oil injection holes evenly distributed along the circumferential direction of the sprocket hub. The hub oil injection holes communicate with the main oil passage inside the hub. The driving sprocket is provided with a plurality of sprocket oil passages corresponding to the hub oil inlet passages one by one and used for communicating with the corresponding hub oil inlet passages. The sprocket oil passages communicate with the oil storage cavity. The planetary gear shaft is rotationally matched with the corresponding arm rod. The space between the differential ring gear and the differential sun gear is the planetary ring channel. The oil outlet end of the hub oil injection hole faces the planetary ring channel.

[0019] Preferably, the sprocket hub is slidably connected to the driving sprocket. The driving sprocket is provided with a front stop body for limiting the sprocket hub, a plurality of rear stop blocks for limiting the sprocket hub, and a hub spring for pressing the sprocket hub against the front stop body. The sprocket hub is provided with a hub ring that can be pushed by the differential shift sleeve.

[0020] When the differential shift sleeve is separated from the sprocket hub: the sprocket hub contacts the front stop body, and the differential shift fork, the front stop body, the hub ring, and the rear stop blocks are arranged in sequence along the axial direction of the rear output shaft. The hub oil inlet passage is aligned and communicated with the corresponding sprocket oil passage.

[0021] When the differential shift sleeve is in contact with the hub ring and the sprocket hub contacts the rear stop block: the differential shift sleeve is combined with the sprocket hub, one end of the hub oil inlet passage adjacent to the driving sprocket is blocked by the driving sprocket, and one end of the sprocket oil passage adjacent to the sprocket hub is blocked by the sprocket hub.

[0022] The beneficial effects of the present invention are as follows: It has working gears such as two-wheel drive high-speed gear, four-wheel drive high-speed torque automatic distribution gear, four-wheel drive high-speed torque ratio constant gear, and four-wheel drive low-speed torque ratio constant gear. Compared with traditional transfer cases, the types of working gears are richer, more functions can be realized, and an oil pump driven by the power input shaft is configured, which can provide better lubrication and cooling and heat dissipation effects for the structures at relatively high positions inside the transfer case housing; it can automatically determine whether to supply oil to the inside of the differential housing according to whether the internal structure of the differential housing works (whether the differential planetary gears rotate). When automatically supplying oil, the lubricating oil will be sprayed at high speed, so that while cooling and dissipating heat, it can effectively wash away the generated iron filings, and the iron filings will leave the inside of the differential housing along with the lubricating oil from the separation gap that exists at this time. When oil supply is not required, the separation gap is exactly in the state blocked by the differential shift sleeve, which can not only prevent the lubricating oil from easily entering the differential housing and resulting in waste of the overall heat dissipation capacity, but also limit the lubricating oil from bringing external iron filings into the differential housing. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic structural view of the present invention;

[0024] Figure 2 is Figure 1 an enlarged view of part A in

[0025] Figure 3 is Figure 1 an enlarged view of part B in

[0026] Figure 4 is Figure 1 an enlarged view of part C in

[0027] Figure 5 is a schematic structural view of the power input shaft of the present invention;

[0028] Figure 6 is a schematic structural view of the differential housing of the present invention;

[0029] Figure 7 is Figure 6 an enlarged view of part D in

[0030] Figure 8 a partial schematic view of the high and low speed shift gear sleeve of the present invention in a certain state;

[0031] Figure 9 is a partial schematic view of the differential shift gear sleeve of the present invention in a certain state;

[0032] Figure 10 is a partial schematic view of the high and low speed shift gear sleeve of the present invention in another state;

[0033] Figure 11 is a schematic structural view of the shift cam at the 2H gear of the present invention;

[0034] Figure 12 is a schematic structural view of the shift cam at the 4A gear of the present invention;

[0035] Figure 13 is a schematic structural view of the shift cam at the 4H gear of the present invention;

[0036] Figure 14 is a schematic structural view of the shift cam at the 4L gear of the present invention;

[0037] Figure 15 is a partial structural schematic view of Embodiment 2 of the present invention;

[0038] Figure 16 is Figure 15 an enlarged view of part E in

[0039] Reference numerals: transfer case housing 1, oil pumping port 1a, magnet block 101, filter screen 102, power input shaft 2, inner shaft hole 2a, oil inlet chamber 2b, input sun gear 201, input sun gear hub 201.1, input planetary gear 202, input planet carrier 203, input planetary gear hub 203.1, input ring gear 204, bowl-shaped oil blocking plug 205, rear output shaft 3, shaft oil passage 3a, oil supply small hole 3b, oil storage chamber 3c, oil supply large hole 3d, shrinkage shaft neck section 3.1, rear output gear hub 301, shaft sleeve 302, first needle roller bearing 303, second needle roller bearing 304, end ball bearing 305, high and low speed shift gear sleeve 401, high and low speed shift fork 402, high and low speed shift fork head 402.1, shift guide shaft 403, return spring 403.1, differential shift gear sleeve 404, separation gap 404a, differential shift fork 405, differential shift fork head 405.1, shift rotating shaft 406, shift cam 407, first flat contact end face 407a, spiral inclined plane 407b, second flat contact end face 407c, first circumferential flat groove 407.1, second circumferential flat groove 407.2, third circumferential flat groove 407.3, coil spring 408, front output shaft 5, driving sprocket 501, sprocket oil passage 501b, sprocket gear hub 501.1, main oil passage inside gear hub 501.1a, oil inlet passage of gear hub 501.1b, oil flushing hole of gear hub 501.1c, front baffle 501.2, rear baffle 501.3, gear hub spring 501.4, gear hub ring 501.5, driven sprocket 502, drive chain 503, differential housing 6, housing friction surface 6a, front side gear hub of housing 6.1, rear side gear hub of housing 6.2, housing limit projection 6.3, housing needle roller bearing 6.4, planet carrier needle roller bearing 6.5, differential planet carrier 601, planet carrier friction surface 601a, planet carrier limit projection 601.1, differential sun gear 602, differential ring gear 603, planetary raceway 603a, ring gear body 603.1, ring gear hub 603.2, mating gear hub 604, gear hub body 604.1, gear hub extension section 604.2, differential planetary gear 605, first clutch disc ring 606, second clutch disc ring 607, third clutch disc ring 608, fourth clutch disc ring 609. Detailed implementation manners

[0040] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present invention.

[0041] Embodiment 1:

[0042] As Figure 1 、 Figure 2 、Figure 3 , Figure 5 , Figure 6 , Figure 8 , Figure 9 , Figure 10 As shown in Figure 10 , a full-time transfer case includes a transfer case housing 1, an oil pump, a power input shaft 2, an input sun gear 201, an input sun gear hub 201.1, a plurality of input planet gears 202, an input planet carrier 203, an input planet gear hub 203.1, an input ring gear 204, a rear output shaft 3, a rear output gear hub 301, a high / low speed shift sleeve 401, a high / low speed shift fork 402, a shift guide shaft 403, a front output shaft 5, a driving sprocket 501, a driven sprocket 502, a transmission chain 503, and a magnet block 101. The oil pump is driven by the power input shaft 2. An axial oil passage 3a supplied with oil by the oil pump and a plurality of oil supply holes 3b communicating with the axial oil passage 3a are provided on the rear output shaft 3;

[0043] It further includes a differential housing 6 with one end open, a differential planet carrier 601 rotatably connected to the driving sprocket 501, a differential sun gear 602 capable of driving the driving sprocket 501, a differential ring gear 603 located inside the differential housing 6, a mating gear hub 604 located inside the differential housing 6, and a plurality of differential planet gears 605 meshing with the differential ring gear 603. The differential housing 6 is rotatably connected to the rear output shaft 3. The differential planet carrier 601 is relatively fixed to the differential housing 6. The differential ring gear 603 drives the rear output shaft 3 through the mating gear hub 604. The differential planet gears 605 mesh with the differential sun gear 602. A planet gear shaft rotatably mating with the differential planet carrier 601 is provided on the differential planet gears 605. A front side gear hub 6.1 and a rear side gear hub 6.2 are provided on the differential housing 6. The input sun gear hub 201.1, the input planet gear hub 203.1, the rear output gear hub 301, and the front side gear hub 6.1 of the housing are all adapted to the high / low speed shift sleeve 401;

[0044] It further includes a differential shift sleeve 404, a differential shift fork 405, and a sprocket gear hub 501.1 capable of driving the driving sprocket 501 to rotate. The open end of the differential housing 6 faces the sprocket gear hub 501.1, and there is a separation gap 404a between the open end of the differential housing 6 and the sprocket gear hub 501.1. The rear side gear hub 6.2 of the housing and the sprocket gear hub 501.1 are both adapted to the differential shift sleeve 404.

[0045] Prior art supplement: The rear output shaft 3 and the power input shaft 2 are coaxially arranged. The input sun gear 201 is fixed on the power input shaft 2. The input sun gear hub 201.1 is fixed on the input sun gear 201. The input planet gear 202 meshes with the input sun gear hub 201.1. The input planet gear 202 meshes with the input ring gear 204. The input planet gear 202 is rotatably connected to the input planet carrier 203. The input planet gear hub 203.1 is fixed on the input planet gear 202. The rear output gear hub 301 is fixed on the rear output shaft 3. The high and low speed shift sleeve 401 is driven by the high and low speed shift fork 402. The high and low speed shift sleeve 401 is slidably connected to the shift guide shaft 403. The driving sprocket 501 is coaxially sleeved on the rear output shaft 3. The driving sprocket 501 is rotatably connected to the rear output shaft 3. The driven sprocket 502 is coaxially fixed on the front output shaft 5. The transmission chain 503 is closed at both ends and bypasses the driving sprocket 501 and the driven sprocket 502. The transmission chain 503 cooperates with the driving sprocket 501. The transmission chain 503 cooperates with the driven sprocket 502. The differential shift sleeve 404 is driven by the differential shift fork 405. The differential shift sleeve 404 is slidably connected to the shift guide shaft 403. The magnet block 101 is located at the inner bottom of the transfer case 1.

[0046] The oil pump can be various conventional oil pumps such as a rotor pump, a gear pump, a vane pump, etc. Setting an oil pump on a transmission and a transfer case also belongs to the prior art. When the internal structure of the transfer case 1 works, some iron filings will be generated due to long-term friction and impact. The lubricating oil can carry away the generated iron filings, and when the lubricating oil passes through the magnet block 101, the magnet block 101 can adsorb the iron filings, thereby reducing the influence of the iron filings on gear wear, bearing wear, wear of seal ring structures, etc. When shifting gears, the high and low speed shift fork can drive the high and low speed shift sleeve to move, and the differential shift fork can drive the differential shift sleeve to move.

[0047] When the present invention works, as Figure 2 、 Figure 3 shown, at this time the present invention is in the 2H gear (two-wheel drive high-speed gear). The high and low speed shift sleeve 401 is combined with the input sun gear hub 201.1, the high and low speed shift sleeve 401 is combined with the rear output gear hub 301, and the differential shift sleeve 404 is separated from the sprocket hub 501.1. The power transmission route is the power input shaft 2, the input sun gear 201, the input sun gear hub 201.1, the high and low speed shift sleeve 401, the rear output gear hub 301, and the rear output shaft 3. The 2H gear is relatively fuel-efficient.

[0048] After the present invention is switched from the 2H gear to the 4A gear (four-wheel drive high-speed torque automatic distribution gear), as Figure 2 、 Figure 9As shown, the high-low speed shift sleeve 401 is combined with the input sun gear hub 201.1, the high-low speed shift sleeve 401 is combined with the front side gear hub 6.1 of the housing, and the differential shift sleeve 404 is separated from the sprocket gear hub 501.1. The power transmission route is the power input shaft 2, the input sun gear 201, the input sun gear hub 201.1, the high-low speed shift sleeve 401, the front side gear hub 6.1 of the housing, the differential housing 6, the differential planet carrier 601, and each planet gear shaft (differential planet gear 605). After that, the power is divided into two paths. One path of power is transmitted from the differential planet gear 605 to the differential ring gear 603, and then from the differential ring gear 603 to the rear output shaft 3 through the mating gear hub 604. The other path of power is transmitted from the differential planet gear 605 to the differential sun gear 602, and then from the differential sun gear 602 to the front output shaft 5 through the driving sprocket 501, the drive chain 503, and the driven sprocket 502.

[0049] When the present invention is in the 4A gear, under normal driving conditions, there is no rotational speed difference between the front and rear wheels of the vehicle, that is, there is no rotational speed difference between the rear output shaft 3 and the front output shaft 5, which is manifested as no relative rotation between the differential ring gear 603 and the differential sun gear 602. When the differential planet gear 605 moves with the differential planet carrier 601, it only makes a revolution around the axis of the rear output shaft 3, and the differential planet gear 605 itself does not rotate. When the vehicle turns (or the vehicle is in other conditions that cause the rotational speeds of the front and rear wheels to be inconsistent), the rotational speeds of the front and rear wheels of the vehicle are different, that is, there is a rotational speed difference between the rear output shaft 3 and the front output shaft 5. Since the rear output shaft 3 is linked with the mating gear hub 604 and the differential ring gear 603, and the front output shaft 5 is linked with the driven sprocket 502, the drive chain 503, the driving sprocket 501, and the differential sun gear 602, there will be a situation where the rotational speeds of the differential ring gear 603 and the differential sun gear 602 are inconsistent, and the differential planet gear 605 thus starts to rotate. In this way, the output torque ratio between the rear output shaft 3 and the front output shaft 5 can be automatically distributed according to their rotational speeds.

[0050] After the present invention is switched from the 4A gear to the 4H gear (constant four-wheel drive high-speed torque ratio gear), as Figure 8 、 Figure 9As shown, the high-low speed shift sleeve 401 is combined with the input sun gear hub 201.1, the high-low speed shift sleeve 401 is combined with the front side hub 6.1 of the housing, and the differential shift sleeve 404 is combined with the sprocket hub 501.1. The power transmission route is the power input shaft 2, the input sun gear 201, the input sun gear hub 201.1, the high-low speed shift sleeve 401, the front side hub 6.1 of the housing, the differential housing 6. Then the power is divided into two paths. One path of power is transmitted from the differential housing 6 to the rear output shaft 3 through the differential planet carrier 601, each planet gear shaft (differential planet gear 605), and the differential ring gear 603. The other path of power is transmitted from the differential housing 6 to the front output shaft 5 through the rear side hub 6.2 of the housing, the differential shift fork 405, the link hub, the driving sprocket 501, the drive chain 503, and the driven sprocket 502.

[0051] When the present invention is in the 4H gear, there is no rotational speed difference between the rear output shaft 3 and the differential housing 6, and there is no rotational speed difference between the front output shaft 5 and the differential housing 6. Therefore, the output torque ratio between the rear output shaft 3 and the front output shaft 5 is constant.

[0052] After the present invention is switched from the 4H gear to the 4L gear (constant four-wheel drive low-speed torque ratio gear), as Figure 9 、 Figure 10 As shown, the high-low speed shift sleeve 401 is combined with the input planet gear hub 203.1, the high-low speed shift sleeve 401 is combined with the front side hub 6.1 of the housing, and the differential shift sleeve 404 is combined with the sprocket hub 501.1. The power transmission route is the power input shaft 2, the input sun gear 201, the input planet gear 202, the input planet carrier 203, the input planet gear hub 203.1, the high-low speed shift sleeve 401, the front side hub 6.1 of the housing, the differential housing 6. Then the power is divided into two paths. One path of power is transmitted from the differential housing 6 to the rear output shaft 3 through the differential planet carrier 601, each planet gear shaft (differential planet gear 605), and the differential ring gear 603. The other path of power is transmitted from the differential housing 6 to the front output shaft 5 through the rear side hub 6.2 of the housing, the differential shift fork 405, the link hub, the driving sprocket 501, the drive chain 503, and the driven sprocket 502.

[0053] When the present invention is in the 4L gear, there is no rotational speed difference between the rear output shaft 3 and the differential housing 6, and there is no rotational speed difference between the front output shaft 5 and the differential housing 6. Therefore, the output torque ratio between the rear output shaft 3 and the front output shaft 5 is constant.

[0054] As Figure 1 、 Figure 4As shown, an oil pumping port 1a is provided at the bottom of the transfer case housing 1. A filter screen 102 is provided at the oil pumping port 1a, and a magnet block 101 is located beside the oil pumping port 1a. The liquid inlet end of the oil pump is connected to the oil pumping port 1a through a tubing. An inner shaft hole 2a is provided on the power input shaft 2. A shaft sleeve 302 that is rotationally and sealingly matched with the inner shaft hole 2a is sleeved on the rear output shaft 3. A bowl-shaped oil blocking plug piece 205 is provided in the inner shaft hole 2a. An oil inlet cavity 2b is jointly formed by the inner wall of the inner shaft hole 2a, the shaft sleeve 302, the outer side wall of the rear output shaft 3, and the bowl-shaped oil blocking plug piece 205. An axial oil passage 3a is connected to the oil inlet cavity 2b, and the liquid outlet end of the oil pump is connected to the oil inlet cavity 2b.

[0055] The shaft sleeve 302 is rotationally and sealingly matched with the inner shaft hole 2a through a plurality of oil blocking sealing rings provided on the shaft sleeve 302, and the oil blocking sealing rings are relatively fixed to the shaft sleeve 302. The lubricating oil at the inner bottom of the transfer case housing 1 reaches the oil inlet cavity 2b through the oil pumping port 1a (filter screen 102), the tubing, the liquid inlet end of the oil pump, and the liquid outlet end of the oil pump, and then can be supplied to the axial oil passage 3a. The magnet block 101 can adsorb the iron filings in the lubricating oil flowing near the magnet block 101. The magnet block 101 is arranged beside the oil pumping port 1a, which can better play the adsorption role (the lubricating oil will continuously flow through the oil pumping port 1a).

[0056] As Figure 1 , Figure 11 , Figure 12 , Figure 13 , Figure 14 As shown, it further includes a shift motor, a shift rotating shaft 406 driven by the shift motor, and a shift cam 407 provided on the shift rotating shaft 406. The high and low speed shift fork 402 includes a high and low speed fork head 402.1, and the differential shift fork 405 includes a differential fork head 405.1. The shift cam 407 is provided with a first circumferential flat groove 407.1, a first spiral inclined guide groove, a second circumferential flat groove 407.2, a second spiral inclined guide groove, and a third circumferential flat groove 407.3 that are adapted to and continuously arranged with the high and low speed fork head 402.1. The shift cam 407 is provided with a first flat contact end face 407a, a spiral inclined face 407b, and a second flat contact end face 407c that are adapted to and continuously arranged with the differential fork head 405.1. The differential shift gear sleeve 404 is always combined with the rear side gear hub 6.2 of the housing. A return spring 403.1 that presses the differential fork head 405.1 against the first flat contact end face 407a, the spiral inclined face 407b, or the second flat contact end face 407c is provided on the shift guide shaft 403;

[0057] When the high and low speed fork head 402.1 is in the first circumferential flat groove 407.1 and the differential fork head 405.1 is pressed against the first flat contact end face 407a: the high and low speed shift gear sleeve 401 is combined with the input sun gear hub 201.1, the high and low speed shift gear sleeve 401 is combined with the rear output gear hub 301, and the differential shift gear sleeve 404 is separated from the sprocket gear hub 501.1;

[0058] When the high-low speed fork head 402.1 is within the second circumferential flat groove 407.2 and the differential fork head 405.1 presses on the first flat contact end face 407a: The high-low speed shift sleeve 401 is combined with the input sun gear hub 201.1, the high-low speed shift sleeve 401 is combined with the front side gear hub 6.1 of the housing, and the differential shift sleeve 404 is separated from the sprocket gear hub 501.1;

[0059] When the high-low speed fork head 402.1 is within the second circumferential flat groove 407.2 and the differential fork head 405.1 presses on the second flat contact end face 407c: The high-low speed shift sleeve 401 is combined with the input sun gear hub 201.1, the high-low speed shift sleeve 401 is combined with the front side gear hub 6.1 of the housing, and the differential shift sleeve 404 is combined with the sprocket gear hub 501.1;

[0060] When the high-low speed fork head 402.1 is within the third circumferential flat groove 407.3 and the differential fork head 405.1 presses on the second flat contact end face 407c: The high-low speed shift sleeve 401 is combined with the input planetary gear hub 203.1, the high-low speed shift sleeve 401 is combined with the front side gear hub 6.1 of the housing, and the differential shift sleeve 404 is combined with the sprocket gear hub 501.1.

[0061] The shift motor realizes "one machine with dual control" through the cooperation between the shift cam 407 and the high-low speed fork head 402.1 and the cooperation between the shift cam 407 and the differential fork head 405.1. That is, there is one shift motor shift cam 407, and the shift cam 407 can drive the high-low speed shift fork 402 (high-low speed fork head 402.1) and the differential shift fork 405 (differential fork head 405.1). Specific descriptions are as follows.

[0062] As Figure 2 、 Figure 3 shown, when the present invention is in the 2H gear (two-wheel drive high-speed gear), the high-low speed fork head 402.1 is within the first circumferential flat groove 407.1 and the differential fork head 405.1 presses on the first flat contact end face 407a. The high-low speed shift sleeve 401 is combined with the input sun gear hub 201.1, the high-low speed shift sleeve 401 is combined with the rear output gear hub 301, and the differential shift sleeve 404 is separated from the sprocket gear hub 501.1.

[0063] When the present invention is in the 2H gear, the shift cam 407 rotates by a certain angle, and the high-low speed fork head 402.1 reaches the second circumferential flat groove 407.2 after passing through the first spiral inclined guide groove (the high-low speed shift fork 402 moves a certain distance towards the sprocket gear hub 501.1). During the above process, the first flat contact end face 407a is always in contact with the differential fork head 405.1, so the differential fork head 405.1 will not be pushed. At this time, as Figure 2 、 Figure 9As shown in the figure, the present invention is in the 4A gear (four-wheel drive high-speed torque automatic distribution gear), the high-low speed shift sleeve 401 is combined with the input sun gear hub 201.1, the high-low speed shift sleeve 401 is combined with the front side gear hub 6.1 of the housing, and the differential shift sleeve 404 is separated from the sprocket gear hub 501.1.

[0064] When the present invention is in the 4A gear, the shift cam 407 continues to rotate a certain angle, and the differential fork head 405.1 reaches the second flat contact end face 407c after passing through the spiral inclined plane 407b (the differential shift fork 405 moves a certain distance towards the sprocket gear hub 501.1). During the above process, the second flat contact end face 407c always contacts the high-low speed fork head, so the differential fork head 405.1 will not be pushed. At this time, as Figure 8 、 Figure 9 shown, the present invention is in the 4H gear (four-wheel drive high-speed torque ratio constant gear), the high-low speed fork head 402.1 is in the second circumferential flat groove 407.2 and the differential fork head 405.1 is pressed on the second flat contact end face 407c, the high-low speed shift sleeve 401 is combined with the input sun gear hub 201.1, the high-low speed shift sleeve 401 is combined with the front side gear hub 6.1 of the housing, and the differential shift sleeve 404 is combined with the sprocket gear hub 501.1.

[0065] When the present invention is in the 4H gear, the shift cam 407 continues to rotate a certain angle, and the high-low speed fork head 402.1 reaches the third circumferential flat groove 407.3 after passing through the second spiral inclined guide groove (the high-low speed shift fork 402 moves a certain distance towards the sprocket gear hub 501.1). During the above process, the second flat contact end face 407c always contacts the differential fork head 405.1, so the differential fork head 405.1 will not be pushed. At this time, as Figure 9 、 Figure 10 shown, the present invention is in the 4L gear (four-wheel drive low-speed torque ratio constant gear), the high-low speed fork head 402.1 is in the third circumferential flat groove 407.3 and the differential fork head 405.1 is pressed on the second flat contact end face 407c, the high-low speed shift sleeve 401 is combined with the input planet gear hub 203.1, the high-low speed shift sleeve 401 is combined with the front side gear hub 6.1 of the housing, and the differential shift sleeve 404 is combined with the sprocket gear hub 501.1.

[0066] As Figure 1 、 Figure 11 、 Figure 12 、 Figure 13 、 Figure 14 shown, the output end of the shift motor drives the shift rotating shaft 406 through a torsion spring 408. The torsion spring 408 is sleeved on the shift rotating shaft 406. One end of the torsion spring 408 is relatively fixed to the output end of the shift motor, and the other end of the torsion spring 408 is relatively fixed to the shift rotating shaft 406.

[0067] After the shift motor drives the coil spring 408, the coil spring 408 can drive the shift cam 407 to rotate. If the high-low speed shift gear sleeve 401 or the differential shift gear sleeve 404 fails to directly engage with the target (input sun gear hub 201.1, rear output gear hub 301, sprocket gear hub 501.1, etc.), the coil spring 408 can maintain the power storage state until the high-low speed shift gear sleeve 401 or the differential shift gear sleeve 404 engages with the target. In this way, the shift motor can be protected to prevent the shift motor from getting stuck.

[0068] like Figure 1 , Figure 5 , Figure 6 As shown, the driving sprocket 501, the shift shaft 406 and the driven sprocket 502 are arranged in sequence from top to bottom, and the input sun gear hub 201.1, the rear output gear hub 301, the input planetary gear hub 203.1, the housing front gear hub 6.1, the housing rear gear hub 6.2, the sprocket gear hub 501.1 and the transmission chain 503 are arranged in sequence along the axial direction of the power input shaft 2.

[0069] like Figure 1 , Figure 6 As shown, the rear output shaft 3 is provided with a first needle bearing 303, a second needle bearing 304 and a terminal ball bearing 305, the first needle bearing 303 cooperates with the rear output shaft 3, the second needle bearing 304 cooperates with the rear output shaft 3, the terminal ball bearing 305 cooperates with the rear output shaft 3, the first needle bearing 303 cooperates with the driving sprocket 501, the second needle bearing 304 cooperates with the driving sprocket 501, the terminal ball bearing 305 cooperates with the transfer case 1, the number of the oil supply holes 3b is three, and the three oil supply holes 3b are arranged in sequence along the axial direction of the rear output shaft 3, among the three oil supply holes 3b: the outlet of the oil supply hole 3b adjacent to the power input shaft 2 is toward the first needle bearing 303, the outlet of the oil supply hole 3b away from the power input shaft 2 is toward the terminal ball bearing 305, and the outlet of the remaining oil supply hole 3b is toward the second needle bearing 304.

[0070] The driving sprocket 501 has many functions to perform. For example, a sprocket hub 501.1 is provided thereon, and it is to cooperate with the differential planet carrier 601 (which can be through bearing cooperation), cooperate with the differential sun gear 602, etc. The first needle bearing 303 and the second needle bearing 304 are used to cooperate with the inner hole of the driving sprocket 501, which can ensure the stability of it and related structures during operation. The end ball bearing 305 can assist in ensuring the relative stability between the transfer case housing 1 and the rear output shaft 3. Three oil supply holes 3b are used to supply oil to the first needle bearing 303, the second needle bearing 304, and the end ball bearing 305, which can not only ensure the lubrication effect between the first needle bearing 303, the second needle bearing 304, the end ball bearing 305 and the structures cooperating with them, reduce the generation of metal chips, but also play the role of heat dissipation and temperature reduction to prevent local overheating. In addition, after the lubricating oil reaches the first needle bearing 303, the second needle bearing 304, or the end ball bearing 305, it will also flow out laterally along the outer wall of the rear output shaft 3 to lubricate and dissipate heat from other surrounding structures.

[0071] As Figure 1 , Figure 6 , Figure 7 As shown, the mating hub 604 includes a hub body 604.1 and a hub extension 604.2, the differential ring gear 603 includes a ring gear body 603.1 and a ring gear hub 603.2, the hub body 604.1 is slidably connected to the ring gear hub 603.2, the hub body 604.1 is slidably connected to the rear output shaft 3, the differential sun gear 602 is slidably connected to the driving sprocket 501, the planet gear shaft is slidably mated with the differential planet carrier 601, the differential ring gear 603 is a helical ring gear, the differential planet gear 605 is a helical gear, the differential sun gear 602 is a helical gear, the differential housing 6 is provided with a housing limit projection 6.3, the differential planet carrier 601 is provided with a planet carrier limit projection 601.1, the differential housing 6 is internally provided with a first clutch disc ring 606 sleeved on the housing limit projection 6.3, a second clutch disc ring 607 sleeved on the hub extension 604.2, a third clutch disc ring 608 sleeved on the driving sprocket 501, and a fourth clutch disc ring 609 sleeved outside the planet carrier limit projection 601.1. The differential housing has a housing friction surface 6a for contacting the first clutch disc ring 606. The housing friction surface 6a, the first clutch disc ring 606, the ring gear hub 603.2, the fourth clutch disc ring 609, the differential planet gear 605, and the third clutch disc ring 608 are arranged in sequence along the axial direction of the rear output shaft 3. The differential planet carrier 601 has a planet carrier friction surface 601a for contacting the third clutch disc ring 608. The housing friction surface 6a, the first clutch disc ring 606, the hub body 604.1, the second clutch disc ring 607, the differential sun gear 602, the third clutch disc ring 608, and the planet carrier friction surface 601a are arranged in sequence along the axial direction of the rear output shaft 3.

[0072] As previously mentioned, when the present invention is in the 4A gear position, if there is no rotational speed difference between the rear output shaft 3 and the front output shaft 5, the differential planetary gear 605 itself will not rotate. Usually, there is a little clearance in the axial direction of the rear output shaft 3 for the first clutch disc ring 606, the second clutch disc ring 607, the third clutch disc ring 608, and the fourth clutch disc ring 609. If there is a rotational speed difference between the rear output shaft 3 and the front output shaft 5, the differential planetary gear 605 itself will rotate. When the differential planetary gear 605 starts to rotate, due to "the differential ring gear 603 is a helical ring gear, the differential planetary gear 605 is a helical gear, and the differential sun gear 602 is a helical gear", and "the hub body 604.1 is slidably connected to the ring gear hub 603.2, the hub body 604.1 is slidably connected to the rear output shaft 3, the differential sun gear 602 is slidably connected to the driving sprocket 501, and the planetary gear shaft is slidably engaged with the differential planet carrier 601", the differential ring gear 603, the differential planetary gear 605, and the differential sun gear 602 will inevitably be subjected to axial forces. Taking Figure 7 the perspective in

[0073] as an example, for instance, if the differential planetary gear 605 is subjected to an axial force to the left, then the differential planetary gear 605 will be pressed against and rubbed with the fourth clutch disc ring 609, and the differential planetary gear 605 will thus decelerate. Another example is that if the differential sun gear 602 is subjected to an axial force to the right, then the differential sun gear 602 will be pressed against and rubbed with the third clutch disc ring 608, and the differential sun gear 602 will thus decelerate. Yet another example is that if the differential ring gear 603 is subjected to an axial force to the left, then the ring gear hub 603.2 will be pressed against and rubbed with the first clutch disc ring 606, and the differential ring gear 603 will thus decelerate. The same applies to other situations. Therefore, when the differential planetary gear 605 rotates, one or more of the first clutch disc ring 606, the second clutch disc ring 607, the third clutch disc ring 608, and the fourth clutch disc ring 609 can play a role in frictional deceleration. That is, when there is a rotational speed difference between the rear output shaft 3 and the front output shaft 5 and the differential planetary gear 605 starts to rotate, the clutch disc rings will automatically perform frictional deceleration on the differential planetary gear 605, the differential ring gear 603, and the differential sun gear 602 (there is a meshing relationship among the differential planetary gear 605, the differential ring gear 603, and the differential sun gear 602. If one decelerates, the other two will also decelerate), thereby quickly reducing the rotational speed of the output shaft with a relatively higher speed, ensuring more reasonable utilization of the output torque (because the output shaft with a relatively higher speed is the slipping output shaft. If its rotational speed is not restricted, then the power or the output torque will be wasted on this slipping output shaft. However, if its rotational speed can be quickly reduced to make it as consistent as possible with the other output shaft, then more power or output torque can be ensured to be distributed to the non-slipping output shaft).

[0073] It should also be noted that the first clutch disc ring is sleeved on the outer housing limit protrusion, but the first clutch disc ring and the outer housing limit protrusion do not have to be rotationally engaged. As long as it is "sleeved on the outside", that is, there is an allowable clearance (play) between the first clutch disc ring and the outer housing limit protrusion. Similarly, there is an allowable play between the second clutch disc ring and the tooth hub extension section, between the third clutch disc ring and the driving sprocket, and between the fourth clutch disc ring and the planetary carrier limit protrusion.

[0074] Embodiment 2: Based on Embodiment 1, as Figure 15 、 Figure 16 shown,

[0075] The differential housing 6 and the rear output shaft 3 are rotationally connected through a housing needle bearing 6.4. The differential planetary carrier 601 and the driving sprocket 501 are rotationally connected through a planetary carrier needle bearing 6.5. The rear output shaft 3 includes a reduced diameter shaft neck section 3.1. The first needle bearing 303, the second needle bearing 304, the outer side wall of the reduced diameter shaft neck section 3.1 and the inner side wall of the driving sprocket 501 jointly enclose an oil storage chamber 3c. A large oil supply hole 3d communicating with the shaft oil passage 3a is provided on the power input shaft 2. The large oil supply hole communicates with the oil storage chamber 3c. The tooth hub 501.1 of the sprocket is provided with a main oil passage 501.1a inside the tooth hub, a number of tooth hub oil inlet passages 501.1b communicating with the main oil passage 501.1a inside the tooth hub, and a plurality of tooth hub oil injection holes 501.1c evenly distributed along the circumference of the tooth hub 501.1 of the sprocket. The tooth hub oil injection holes 501.1c communicate with the main oil passage 501.1a inside the tooth hub. The driving sprocket 501 is provided with a number of sprocket oil passages 501a corresponding one-to-one to the tooth hub oil inlet passages 501.1b and used to communicate with the corresponding tooth hub oil inlet passages 501.1b. The sprocket oil passages 501a communicate with the oil storage chamber 3c. The space between the differential ring gear 603 and the differential sun gear 602 is a planetary ring passage 603a. The oil outlet end of the tooth hub oil injection hole 501.1c faces the planetary ring passage 603a.

[0076] The tooth hub 501.1 of the sprocket is slidably connected to the driving sprocket 501. The driving sprocket 501 is provided with a front stop body 501.2 for limiting the tooth hub 501.1, a number of rear stop blocks 501.3 for limiting the tooth hub 501.1, and a tooth hub spring 501.4 for pressing the tooth hub 501.1 against the front stop body 501.2. The tooth hub 501.1 of the sprocket is provided with a tooth hub ring 501.5 that can be pushed by the differential shift sleeve 404;

[0077] When the differential shift sleeve 404 is separated from the tooth hub 501.1 of the sprocket: The tooth hub 501.1 contacts the front stop body 501.2. The differential shift fork 405, the front stop body 501.2, the tooth hub ring 501.5, and the rear stop blocks 501.3 are arranged in sequence along the axial direction of the rear output shaft 3. The tooth hub oil inlet passages 501.1b are aligned and communicated with the corresponding sprocket oil passages 501a;

[0078] When the differential shift sleeve 404 abuts against the hub ring 501.5 and the sprocket hub 501.1 contacts the stop block 501.3: The differential shift sleeve 404 is combined with the sprocket hub 501.1. One end of the hub oil inlet passage 501.1b adjacent to the driving sprocket 501 is blocked by the driving sprocket 501, and one end of the sprocket oil passage 501a adjacent to the sprocket hub 501.1 is blocked by the sprocket hub 501.1.

[0079] In this embodiment, when the present invention is in the 2H gear, 4H gear or 4L gear, the differential shift fork 405 is combined with the sprocket hub 501.1. At this time, the differential planet gear 605 does not rotate by itself. Therefore, the frictional force between the differential planet gear 605 and the differential sun gear 602 is small (even none), the wear is very small, and the heat generation is very little. The frictional force between the differential planet gear 605 and the differential ring gear 603 is small (even none), the wear is very small, and the heat generation is very little. At this time, almost no lubrication is required inside the differential housing 6. The lubricating oil lifted upward by the moving structures (such as the driven sprocket 502, the shift cam 407, the lower part of the transmission chain 503, etc.) below the transmission housing is sufficient to lubricate the upper structures inside the differential housing 6.

[0080] When the present invention is in the 2H gear, 4H gear or 4L gear, the differential shift sleeve 404 abuts against the hub ring 501.5 and the sprocket hub 501.1 contacts the stop block 501.3. One end of the hub oil inlet passage 501.1b adjacent to the driving sprocket 501 is blocked by the driving sprocket 501, and one end of the sprocket oil passage 501a adjacent to the sprocket hub 501.1 is blocked by the sprocket hub 501.1. After the lubricating oil sucked by the oil pump enters the shaft oil passage 3a, there are two directions. One direction of the lubricating oil is to supply oil to the first needle roller bearing 303, the second needle roller bearing 304 and the end ball bearing 305 through three oil supply holes 3b, which can not only ensure the lubrication effect between the first needle roller bearing 303, the second needle roller bearing 304, the end ball bearing 305 and the structures cooperating with them, reduce the generation of metal chips, but also play the role of heat dissipation and temperature reduction to prevent local overheating. In addition, after the lubricating oil reaches the first needle roller bearing 303, the second needle roller bearing 304 or the end ball bearing 305, it will also flow out laterally along the outer wall of the rear output shaft 3 to lubricate and dissipate heat for other surrounding structures; Another direction of the lubricating oil is to enter the oil storage cavity 3c through the large oil supply hole 3d, then enter the gap between the sprocket hub 501.1 and the driving sprocket 501 through the sprocket oil passage 501a, and then flow out laterally along the outer wall of the driving sprocket 501 to lubricate and dissipate heat for other surrounding structures.

[0081] When the present invention is in the 4A gear position, the differential planetary gear 605 rotates frequently, and the first clutch disc ring 606, the second clutch disc ring 607, the third clutch disc ring 608, and the fourth clutch disc ring 609 also frequently play a frictional role. Therefore, the heat generated inside the differential housing 6 is very large (overheating of gears and clutch discs can easily lead to functional attenuation or even rapid damage), and relatively more iron filings are generated (there are many gears inside the differential housing 6, and it is particularly afraid of a large amount of iron filings because iron filings can easily damage the surfaces of gears and clutch discs). When the present invention is in the 4A gear position, the differential shift sleeve 404 is separated from the sprocket hub 501.1, and the sprocket hub 501.1 contacts the front stop body 501.2. The differential shift fork 405, the front stop body 501.2, the hub ring 501.5, and the rear stop block 501.3 are arranged in sequence along the axial direction of the rear output shaft 3. The hub oil inlet passage 501.1b is aligned and communicated with the corresponding sprocket oil passage 501a. After the lubricating oil sucked by the oil pump enters the shaft oil passage 3a, a large amount of it will enter the oil storage chamber 3c through the large oil supply hole 3d, then enter the main oil passage 501.1a inside the hub through the sprocket oil passage 501a and the hub oil inlet passage 501.1b, and then rush into the planetary ring passage 603a at a relatively high flow rate through each hub oil flushing hole 501.1c. After passing through the planetary ring passage 603a, it rushes into the differential housing 6. In this way, not only can the lubrication effect on the moving structures inside the differential housing 6 be greatly enhanced and the heat dissipation effect on the inside of the differential housing 6 be significantly improved, but also the generated iron filings can be washed away in time. The iron filings will leave the inside of the differential housing 6 along with the lubricating oil through the planetary ring passage 603a and the separation gap 404a (at this time, it is exactly the state where the differential shift sleeve 404 does not block the separation gap 404a) and fall to the bottom inside the transmission housing. Since the lubricating oil in the shaft oil passage 3a will be quickly and abundantly supplied to the oil storage chamber 3c at this time, the oil pumping efficiency at the oil pumping port 1a is greatly increased (the flow rate per unit time is greatly increased), which is more conducive to the falling lubricating oil passing through the oil pumping port 1a. Before flowing through the oil pumping port 1a, since the magnet block 101 is beside the oil pumping port 1a, the iron filings in the lubricating oil can be adsorbed more efficiently and quickly.

[0082] Two more points need to be explained:

[0083] First, since "the first needle roller bearing 303, the second needle roller bearing 304, the outer side wall of the shrinkage shaft neck section 3.1, and the inner side wall of the driving sprocket 501 jointly enclose an oil storage chamber 3c", a small part of the lubricating oil in the oil storage chamber 3c will also be directly supplied to the first needle roller bearing 303 and the second needle roller bearing 304 (the needle roller bearings themselves are not fully sealed parts). Compared with the situation where there is only the oil supply small hole 3b, the lubrication and cooling effects on the first needle roller bearing 303 and the second needle roller bearing 304 can be improved.

[0084] Second, when the present invention is in the 2H gear, 4H gear or 4L gear, the amount of oil entering the gap between the sprocket hub 501.1 and the driving sprocket 501 from the sprocket oil passage 501a will not be too large (the back pressure is relatively large, so the oil pumping efficiency of the oil pump is relatively low. As a result, there is more oil at the lower part of the transmission, which is more conducive to the movement structure at the lower part of the transmission housing to stir and lift up the lubricating oil), and at this time, the separation gap 404a is blocked by the differential shift sleeve 404 (but not sealed), and the lifted lubricating oil will not easily enter the differential housing 6 (the lubricating effect will not be wasted, and iron filings will not enter the differential housing 6. At this time, the lifted lubricating oil can go to other structures that require lubrication and heat dissipation more, or quickly fall, which is more conducive to the movement structure at the lower part of the transmission housing to lift up the lubricating oil).

[0085] In this embodiment, the lubricating oil rushes into the planetary ring passage 603a at a relatively high flow rate through each hub oil injection hole 501.1c (the liquid flow rushes into the planetary ring passage 603a), and after passing through the planetary ring passage 603a, it rushes into the differential housing 6. The differential planet carrier 601 has a certain interference with the liquid flow. It can be designed as "the differential planet carrier 601 includes a planet carrier base cooperating with the planet carrier needle bearing 6.5 and three arm rods corresponding to the planetary gear shafts one by one, and the planetary gear shafts are rotationally matched with the corresponding arm rods". In this way, the blockage of the liquid flow can be minimized (only the arm rods will affect the liquid flow), ensuring a high efficiency of the liquid flow rushing into the differential housing 6, and further improving the lubrication, cooling and heat dissipation, and iron filings removal effects inside the differential housing 6.

[0086] The embodiments of the present invention have been introduced in detail above. Specific examples are used in this article to elaborate on the principles and implementation manners of the present invention. The descriptions of the above embodiments are only used to help understand the method and its core idea of the present invention; at the same time, for those skilled in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A full-time transfer case, comprising a transfer case housing, an oil pump, a power input shaft, an input sun gear, an input sun gear hub, a plurality of input planet gears, an input planet carrier, an input planet gear hub, an input ring gear, a rear output shaft, a rear output gear hub, a high / low speed shift sleeve, a high / low speed shift fork, a shift guide shaft, a front output shaft, a driving sprocket, a driven sprocket, a transmission chain and a magnet block. The oil pump is driven by the power input shaft. An axial oil passage supplied with oil by the oil pump and a plurality of oil supply holes communicating with the axial oil passage are provided on the rear output shaft. Its characteristics are that, it further comprises a differential housing with one end open, a differential planet carrier rotatably connected to the driving sprocket, a differential sun gear capable of driving the driving sprocket, a differential ring gear located in the differential housing, a mating gear hub located in the differential housing, and a plurality of differential planet gears meshing with the differential ring gear. The differential housing is rotatably connected to the rear output shaft. The differential planet carrier is relatively fixed to the differential housing. The differential ring gear drives the rear output shaft through the mating gear hub. The differential planet gears mesh with the differential sun gear. A planet gear shaft rotatably mating with the planet carrier is provided on the differential planet gears. A front side gear hub of the housing and a rear side gear hub of the housing are provided on the differential housing. The input sun gear hub, the input planet gear hub, the rear output gear hub and the front side gear hub of the housing are all adapted to the high / low speed shift sleeve; it further comprises a differential shift sleeve, a differential shift fork and a sprocket gear hub capable of driving the driving sprocket to rotate. The open end of the differential housing faces the sprocket gear hub, and there is a separation gap between the open end of the differential housing and the sprocket gear hub. The rear side gear hub of the housing and the sprocket gear hub are both adapted to the differential shift sleeve; the differential housing is rotatably connected to the rear output shaft through an outer race needle bearing of the housing. The differential planet carrier is rotatably connected to the driving sprocket through an outer race needle bearing of the planet carrier. The rear output shaft includes a constricted shaft neck section. A first needle bearing, a second needle bearing, the outer side wall of the constricted shaft neck section and the inner side wall of the driving sprocket jointly enclose an oil storage cavity. A large oil supply hole communicating with the axial oil passage is provided on the power input shaft. The large oil supply hole communicates with the oil storage cavity. A main oil passage inside the gear hub, a plurality of oil inlet passages of the gear hub communicating with the main oil passage inside the gear hub and a plurality of oil flushing holes evenly distributed along the circumferential direction of the sprocket gear hub are provided on the sprocket gear hub. The oil flushing holes communicate with the main oil passage inside the gear hub. A plurality of sprocket oil passages corresponding to the oil inlet passages of the gear hub one by one and used for communicating with the corresponding oil inlet passages of the gear hub are provided on the driving sprocket. The sprocket oil passages communicate with the oil storage cavity. The planet gear shaft rotatably mates with the corresponding arm rod. The space between the differential ring gear and the differential sun gear is a planetary raceway. The oil outlet end of the oil flushing hole of the gear hub faces the planetary raceway; the sprocket gear hub is slidably connected to the driving sprocket. A front stop body for limiting the sprocket gear hub, a plurality of rear stop blocks for limiting the sprocket gear hub and a gear hub spring for pressing the sprocket gear hub against the front stop body are provided on the driving sprocket. A gear hub ring capable of being pushed by the differential shift sleeve is provided on the sprocket gear hub; When the differential shift sleeve is separated from the sprocket gear hub: the sprocket gear hub contacts the front stop body. The differential shift fork, the front stop body, the gear hub ring and the rear stop blocks are arranged in sequence along the axial direction of the rear output shaft. The oil inlet passages of the gear hub are aligned and communicated with the corresponding sprocket oil passages; When the differential shift gear sleeve is in contact with the gear hub ring and the sprocket gear hub contacts the rear stop: the differential shift gear sleeve is combined with the sprocket gear hub, one end of the oil inlet passage of the gear hub adjacent to the driving sprocket is blocked by the driving sprocket, and one end of the sprocket oil passage adjacent to the sprocket gear hub is blocked by the sprocket gear hub.

2. The all-time four-wheel drive according to claim 1, characterized in that An oil extraction port is provided at the bottom of the transfer case housing. A filter screen is provided at the oil extraction port. The magnet block is beside the oil extraction port. The liquid inlet end of the oil pump is connected to the oil extraction port through a tubing. An inner shaft hole is provided on the power input shaft. A shaft sleeve that is rotationally and sealingly fitted with the inner shaft hole is sleeved on the rear output shaft. A bowl-shaped oil blocking plug piece is provided in the inner shaft hole. The inner shaft hole wall, the shaft sleeve, the outer side wall of the rear output shaft, and the bowl-shaped oil blocking plug piece jointly enclose an oil inlet cavity. The shaft oil passage communicates with the oil inlet cavity. The liquid outlet end of the oil pump communicates with the oil inlet cavity.

3. A full-time transfer case according to claim 1, characterized in that, It further includes a shift motor, a shift rotating shaft driven by the shift motor, and a shift cam provided on the shift rotating shaft. The high and low speed shift fork includes a high and low speed fork head. The differential shift fork includes a differential fork head. The shift cam is provided with a first circumferential flat groove, a first spiral inclined guide groove, a second circumferential flat groove, a second spiral inclined guide groove, and a third circumferential flat groove that are adapted to the high and low speed fork head and are continuously arranged. The shift cam is provided with a first flat contact end surface, a spiral inclined surface, and a second flat contact end surface that are adapted to the differential fork head and are continuously arranged. The differential shift gear sleeve is always combined with the rear side gear hub of the housing. A return spring that presses the differential fork head against the first flat contact end surface, the spiral inclined surface, or the second flat contact end surface is provided on the shift guide shaft; When the high and low speed fork head is in the first circumferential flat groove and the differential fork head is pressed against the first flat contact end surface: the high and low speed shift gear sleeve is combined with the input sun gear hub, the high and low speed shift gear sleeve is combined with the rear output gear hub, and the differential shift gear sleeve is separated from the sprocket gear hub; When the high and low speed fork head is in the second circumferential flat groove and the differential fork head is pressed against the first flat contact end surface: the high and low speed shift gear sleeve is combined with the input sun gear hub, the high and low speed shift gear sleeve is combined with the front side gear hub of the housing, and the differential shift gear sleeve is separated from the sprocket gear hub; When the high and low speed fork head is in the second circumferential flat groove and the differential fork head is pressed against the second flat contact end surface: the high and low speed shift gear sleeve is combined with the input sun gear hub, the high and low speed shift gear sleeve is combined with the front side gear hub of the housing, and the differential shift gear sleeve is combined with the sprocket gear hub; When the high and low speed fork head is in the third circumferential flat groove and the differential fork head is pressed against the second flat contact end surface: the high and low speed shift gear sleeve is combined with the input planetary gear hub, the high and low speed shift gear sleeve is combined with the front side gear hub of the housing, and the differential shift gear sleeve is combined with the sprocket gear hub.

4. The full-time transfer case according to claim 3, characterized in that, The output end of the shift motor drives the shift rotating shaft through a torsion spring. The torsion spring is sleeved on the shift rotating shaft. One end of the torsion spring is relatively fixed to the output end of the shift motor, and the other end of the torsion spring is relatively fixed to the shift rotating shaft.

5. A full-time transfer case according to claim 1 or 2 or 3 or 4, characterized in that, The driving sprocket, the shift rotating shaft, and the driven sprocket are arranged in sequence from top to bottom. The input sun gear hub, the rear output gear hub, the input planetary gear hub, the front side gear hub of the housing, the rear side gear hub of the housing, the sprocket gear hub, and the transmission chain are arranged in sequence along the axial direction of the power input shaft.

6. A full-time transfer case according to claim 1, characterized in that, The rear output shaft is provided with a first needle roller bearing, a second needle roller bearing and an end ball bearing. The first needle roller bearing is fitted with the rear output shaft, the second needle roller bearing is fitted with the rear output shaft, and the end ball bearing is fitted with the rear output shaft. The first needle roller bearing is engaged with the driving sprocket, the second needle roller bearing is engaged with the driving sprocket, and the end ball bearing is engaged with the transfer case housing. The number of oil supply small holes is three, and the three oil supply small holes are arranged in sequence along the axial direction of the rear output shaft. Among the three oil supply small holes: the outlet of the oil supply small hole adjacent to the power input shaft faces the first needle roller bearing, the outlet of the oil supply small hole far from the power input shaft faces the end ball bearing, and the outlet of the remaining one oil supply small hole faces the second needle roller bearing.

7. A full-time transfer case according to claim 1, characterized in that, The mating gear hub includes a gear hub body and a gear hub extension section. The differential ring gear includes a ring gear body and a ring gear hub. The gear hub body is slidably connected with the ring gear hub, the gear hub body is slidably connected with the rear output shaft, the differential sun gear is slidably connected with the driving sprocket, the planetary gear shaft is slidably fitted with the differential planet carrier. The differential ring gear is a helical ring gear, the differential planetary gear is a helical gear, and the differential sun gear is a helical gear. The differential housing is provided with a housing limiting projection, the differential planet carrier is provided with a planet carrier limiting projection. Inside the differential housing, there are a first clutch disc ring sleeved on the housing limiting projection, a second clutch disc ring sleeved on the gear hub extension section, a third clutch disc ring sleeved on the driving sprocket, and a fourth clutch disc ring sleeved outside the planet carrier limiting projection. The differential housing has a housing friction surface for contacting the first clutch disc ring. The housing friction surface, the first clutch disc ring, the ring gear hub, the fourth clutch disc ring, the differential planetary gear and the third clutch disc ring are arranged in sequence along the axial direction of the rear output shaft. The differential planet carrier has a planet carrier friction surface for contacting the third clutch disc ring. The housing friction surface, the first clutch disc ring, the gear hub body, the second clutch disc ring, the differential sun gear, the third clutch disc ring and the planet carrier friction surface are arranged in sequence along the axial direction of the rear output shaft.

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