Full-time four-wheel drive transfer case and vehicle

Abstract

The full-time four-wheel drive transfer case comprises a case, an input shaft, a front output shaft, a rear output shaft and a differential mechanism are rotationally arranged in the case, the input shaft is coaxially matched with a front output shaft driving gear in a sliding mode, and the front output shaft is coaxially and fixedly connected with a front output shaft driven gear; the front output shaft driving gear and the front output shaft driven gear are connected through a transfer case transmission part to transmit power, an input connector and two output connectors are arranged in the differential mechanism, the input shaft is fixedly connected with the input connector of the differential mechanism, and the output shaft is fixedly connected with the output connector of the differential mechanism. The front output shaft driving gear is fixedly connected with a front output connector in the differential mechanism, and the rear output shaft is fixedly connected with a rear output connector in the differential mechanism. According to the full-time four-wheel drive transfer case, a vehicle can have the full-time four-wheel drive function, meanwhile, the high-strength cross-country requirement can be met, the differential function can be provided during four-wheel full-load drive, and the vehicle running safety and the riding comfort are greatly improved.

Description

Technical Field

[0001] The present application relates to the technical field of automobile transfer cases, and in particular to a full-time four-wheel drive transfer case and a vehicle. Background Art

[0002] A transfer case is a device that distributes the power of the prime mover (engine or electric motor), which can split the power output into two and output it to the front axle or rear axle respectively.

[0003] Currently, the transfer case of an off-road vehicle or SUV, as described in Patent 202122369897.3, first distributes the input power to the rear output shaft, and then transmits the power to the front output shaft by tightening the multi-plate clutch as needed.

[0004] The main disadvantages of the above technology are: this power transmission method has at least three problems. First, the working process of transmitting power to the front output shaft by compressing the multi-plate clutch causes the friction plate of the multi-plate clutch to be subjected to a large friction force. This friction force will cause the friction plate to generate heat and wear, and eventually lead to clutch failure; second, the input shaft and the rear output shaft are connected at a constant speed (or a constant speed ratio), that is, the speed of the rear output shaft is always equal to (or proportional to) the speed of the input shaft. If a large torque is transmitted to the front output shaft, the multi-plate clutch must be compressed, which makes the front and rear output shafts become a constant speed connection, without a differential. The loss of differential reduces the stability and comfort of the vehicle's driving, and at the same time brings abnormal wear of the transmission mechanism and tires, which also poses a hidden danger to driving safety; third, this structure is difficult to meet the needs of long-term and high-intensity off-road driving, and is prone to high temperature of the transfer case and wear and failure of the friction plate. Utility Model Content

[0005] In order to overcome the above technical shortcomings, the present application provides a full-time four-wheel drive transfer case.

[0006] A full-time four-wheel drive transfer case comprises a case, in which an input shaft, a front output shaft, a rear output shaft and a differential are rotatably arranged, the input shaft being coaxially sleeved with a front output shaft driving gear, the front output shaft being coaxially fixedly connected to a front output shaft driven gear, the front output shaft driving gear and the front output shaft driven gear being connected via a transfer case transmission member to transmit power, the differential having a total of one input connector and two output connectors, the input shaft being fixedly connected to the input connector of the differential, the front output shaft driving gear being slidingly connected to the front output connector of the differential via a spline, and the rear output shaft being slidingly connected to the rear output connector of the differential via a spline.

[0007] The car's power enters the transfer case through the input shaft, first driving the differential to rotate, and the differential then drives the front (rear) output shaft to rotate, thereby realizing the full-time four-wheel drive function.

[0008] The differential can be an open differential, a limited slip differential or an open differential with a lock. Because when one output shaft of an open differential slips, according to the principle that the open differential does not differentiate torque but differentiates speed, the other output shaft will also lose driving force, causing the vehicle's passability to deteriorate. Therefore, the differential generally uses a limited slip differential or an open differential with a lock, and the vehicle's passability will be better.

[0009] The transfer case transmission element connecting the front output shaft's main and driven gears usually uses a common constant velocity transmission element such as a chain or gear.

[0010] When the vehicle is running normally, the differential pushes the front and rear output shafts to rotate at the same time, and the power is transmitted through the output connector of the differential. Because the power is not transmitted by friction, the wear is very small, so it is durable.

[0011] When the road surface is not smooth enough or when turning, the different speed requirements fed back from the front and rear axles of the vehicle are transmitted to the differential through the front output shaft and the rear output shaft. The differential distributes different speeds to the front and rear axles according to the speed requirements of the front and rear output shafts, so that the input shaft speed, the front output shaft speed, and the rear output shaft speed can rotate at different speeds, providing driving force to the front and rear axles at the same time, making the vehicle run more smoothly. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural cross-sectional view of an embodiment of the present application.

[0013] Figure 2 This is a cross-sectional view of an example of a differential in an embodiment of the present application, used to illustrate the assembly relationship of various internal components.

[0014] Figure 3 Schematic diagram of the differential transmission assembly inside the differential of this embodiment.

[0015] Figure 4 It is a cross-sectional view of the front and rear output connectors inside the differential of this embodiment.

[0016] Figure 5 It is an isometric view of the front and rear output connectors inside the differential of this embodiment.

[0017] Figure 6 It is a front view of the differential case of the differential in this embodiment.

[0018] Figure 7 It is a front view of the end cover of the differential in this embodiment.

[0019] Figure 8This is a partial cross-sectional view of the differential of this embodiment, used to illustrate the structure of the circulation loop of the differential and the coordination relationship between the differential and the differential transmission assembly.

[0020] Figure 9 It is a cross-sectional view of the installation relationship between the housing and the end cover of the differential in this embodiment.

[0021] Figure 10 This is an isometric view of the squeeze brake portion inside the differential of this embodiment. DETAILED DESCRIPTION

[0022] The following is combined with Figure 1-10 This application is described in further detail.

[0023] The present application embodiment discloses a full-time four-wheel drive transfer case, Figure 1 A full-time four-wheel drive transfer case includes a case 1, in which an input shaft 2, a front output shaft 3, a rear output shaft 4 and a differential 5 are rotatably arranged. A front output shaft driving gear 31 is coaxially sleeved on the input shaft 2, and a front output shaft driven gear 32 is coaxially fixed to the front output shaft 3. The front output shaft driving gear 31 and the front output shaft driven gear 32 are connected to each other through a transfer case transmission member 33 to transmit power. There are three connectors inside the differential 5, namely, an input connector 51, a front output connector 52, and a rear output connector 53.

[0024] The portion of input shaft 2 that extends outside of chassis 1 is splined for constant velocity connection with the vehicle's transmission output shaft, thereby inputting power into the transfer case. A bearing is mounted on the end of input shaft 2 inside chassis 1, near the output shaft. This bearing supports input shaft 2 and also serves to axially secure it. Input shaft 2 is inserted into one side of the rear output shaft 4, with a bearing or sleeve installed between them to provide support and axial positioning, allowing the rear output shaft 4 to rotate relative to the input shaft 2, supported by the bearing.

[0025] The input connector 51 of the differential 5 is part of the differential housing 54. The input connector 51 is fixedly connected to the external splines on the input shaft 2 via the internal splines 511 of the input connector, so that the differential housing 54 and the input shaft 2 rotate at the same speed. The differential front output connector 52 is slidingly connected to the front output shaft driving gear 31 via splines, and the differential rear output connector 53 is slidingly connected to the rear output shaft 4 via splines.

[0026] The rear output shaft 4 is fixed to the chassis 1 through a bearing, and the shaft portion extending outside the transfer case is fixedly connected to the rear output flange 6. The rear output flange 6 is then fixedly connected to the rear drive shaft of the car to transmit power to the rear axle.

[0027] The front output shaft driving gear 31 is connected to the front output shaft driven gear 32 via a transfer case transmission 33. The transfer case transmission 33 can be a component such as a chain or gear that can transmit power at a constant speed. The output shaft of the front output shaft 3 is fixedly connected to the front output flange 7. The front output flange 7 is in turn fixedly connected to the vehicle's front drive shaft, thereby transmitting power to the front axle.

[0028] After the car starts, the power transmitted from the engine (or electric motor) and the gearbox drives the input shaft 2 of the transfer case to rotate, and the differential case 54 rotates at the same speed as the input shaft 2.

[0029] Depending on the road conditions and driving state, the power transmission process is as follows:

[0030] In the first case, when the road surface is sufficiently flat and the car is traveling straight, the rotational speeds of the front and rear drive shafts of the car are equal. In this case, the front output shaft 3 and the rear output shaft 4 of the transfer case rotate at the same speed, and the differential housing 54 drives the front differential output connector 52 and the rear differential output connector 53 to rotate at the same speed. This is a non-differential driving state.

[0031] The second situation is that when the road surface is not smooth or the car needs to turn, the rotation speeds of the front and rear drive shafts of the car are not equal. At this time, the front output shaft 3 and the rear output shaft 4 of the transfer case rotate at unequal speeds, and the differential housing 54 drives the differential front output connector 52 and the differential rear output connector 53 to rotate at unequal speeds. At this time, it is a differential driving state.

[0032] The third situation is that when one of the wheels on the front axle has insufficient adhesion to the ground, if the differential 5 is an open differential, the front output shaft 3 will rotate rapidly, while the rear output shaft 4 will slow down or stop, which is the case of front wheel slippage;

[0033] The fourth situation is when one of the wheels on the rear axle has insufficient adhesion to the ground. If the differential 5 is an open differential, the rear output shaft 4 will rotate rapidly while the front output shaft 3 will slow down or stop. This is the case of rear wheel slippage.

[0034] In the above four situations, when the wheels slip, if the differential 5 is an open differential and there is no differential lock, the vehicle's maneuverability will be reduced, and the vehicle may even get stuck and unable to escape. If a differential lock or a limited slip differential is used, the vehicle's maneuverability will be greatly improved.

[0035] Therefore, the form of the differential 5 of this full-time four-wheel drive transfer case is very important. Generally, a limited slip differential or an open differential with a lock is used to improve the vehicle's passing ability.

[0036] The following is combined with Figure 2-10The differential 5 used in the embodiment of the present application is listed as an example. It should also be noted that the differential 5 used in the embodiment of the present application can also be the differential disclosed in CN117267339A.

[0037] Refer to the attached Figure 2 The differential 5 is composed of an input connector 51, a front output connector 52, a rear output connector 53, a differential housing 54, a differential transmission assembly 55, a squeeze brake part 56, and an end cover 57.

[0038] Refer to the attached Figure 6-8 The differential housing 54 is provided with a guide groove 541, a circulation through hole 542, and a spacer ring 544. The guide groove 541 and the circulation through hole 542 penetrate the differential housing 54 along the axis of the differential housing 54. The guide groove 541, the circulation through hole 542, and the connecting grooves 572 on the two end covers 57 together form a closed cavity (i.e., a circulation loop 543), allowing the differential transmission assembly 55 to circulate within the circulation loop 543. Multiple circulation loops 543 are evenly arranged along the circumference of the differential.

[0039] The partition ring 544 is fixedly disposed on the inner side of the differential housing 54 to separate the front output connector 52 from the rear output connector 53 .

[0040] Refer to the attached Figure 4-5 The front output connector 52 includes a first outer tube 522, a first inner tube 524, and a first connecting portion 526. The first outer tube 522 is sleeved on the outside of the first inner tube 524. The first outer tube 522 and the first inner tube 524 are connected via the first connecting portion 526. A first spiral groove 521 is formed on the outer wall of the first outer tube 522.

[0041] The rear output connector 53 includes a second outer tube 532, a second inner tube 534, and a second connecting portion 536. The second outer tube 532 is sleeved on the outside of the second inner tube 534. The second outer tube 532 and the second inner tube 534 are connected via the second connecting portion 536. A second spiral groove 531 is defined on the outer wall of the second outer tube 532.

[0042] The first spiral groove 521 and the second spiral groove 531 have opposite rotation directions.

[0043] Refer to the attached Figure 2-3 The differential 5 also includes a plurality of differential transmission assemblies 55 , each of which includes a plurality of differential transmission members 551 , and the plurality of differential transmission members 551 are close to each other and fully distributed in the circulation loop 543 .

[0044] Refer to the attached Figure 2 The differential 5 further includes four sets of squeeze brake portions 56 , which are provided between the partition ring 544 and the front output connector 52 , between the partition ring 544 and the rear output connector 53 , and between the end cover 57 and the front output connector 52 , and between the end cover 57 and the rear output connector 53 in the axial direction of the differential 5 .

[0045] Refer to the attached Figure 10 The squeeze brake portion 56 includes a plurality of first friction plates 561 and a plurality of second friction plates 562, which are alternately arranged along the axial direction. The first friction plates 561 are drivingly connected to the differential case 54, and the second friction plates 562 are drivingly connected to the front output connector 52 or the rear output connector 53. One of the first friction plates 561 and the second friction plates 562 is an outer friction plate, and the other is an inner friction plate.

[0046] Refer to the attached Figure 2 The two end covers 57 are respectively fixed to the two ends of the differential housing 54.

[0047] Refer to the attached Figure 2 、 7 -8, the end cover 57 includes an end cover spline hub 571, which is fixedly arranged on the side of the end cover 57 facing the differential housing 54 and is used for sliding connection with the first friction plate 561 or the second friction plate 562. A connecting groove 572 is opened on the end cover 57 to enclose and form the circulation loop 543.

[0048] Refer to the attached Figure 9 The differential housing 54 and the two end covers 57 are assembled into one body by bolts. The input connector 51 is fixed on the differential housing 54. The input connector 51 is provided with an input connector internal spline 551 for transmission connection with the input shaft 2.

[0049] Refer to the attached Figure 2 The front output connector 52 and the rear output connector 53 are respectively placed on either side of the separator ring 544, and the squeeze brake 56 is distributed between the end cover 57, the front output connector 52, the separator ring 544, and the rear output connector 53. The differential transmission assembly 55 is placed in the circulation loop 543, and the portion of the differential transmission member 551 exposed outside the guide groove 541 is engaged with the first spiral groove 521 and the second spiral groove 531.

[0050] The differential 5 works like this:

[0051] When the vehicle is traveling normally on a straight road, the input shaft 2 transmits engine power to the input connector 51, driving the differential case 54 to rotate. The differential case 54 transmits the rotational torque to the front output connector 52 and the rear output connector 53 simultaneously through the differential transmission assembly 55. If the rotational resistance torques experienced by the front output connector 52 and the rear output connector 53 are the same at this time, the axial forces exerted by the differential transmission member 551 located in the first spiral groove and the differential transmission member 551 located in the second spiral groove on the front output connector 52 and the rear output connector 53 in the axial direction are equal in magnitude and opposite in direction. At this time, the front output connector 52 and the rear output connector 53 have a tendency to move toward / away from each other under the push of the axial force of the differential transmission member 551, which makes it impossible for the differential transmission member 551 to transmit torque between the first spiral groove and the second spiral groove (i.e., the differential transmission member 551 is relatively When the front output connector 52 and the rear output connector 53 are stationary), the differential transmission member 551 pushes the corresponding first spiral groove and the second spiral groove respectively. Under the action of the axial component force of the differential transmission member 551, the front output connector 52 and the rear output connector 53 have a tendency to slide away from / toward each other along the axial direction. However, due to the restrictions of the differential housing 54, the squeeze brake 56 and the end cover 57, the front output connector 52 and the rear output connector 53 are blocked from moving in the axial direction and can only remain relatively stationary with the differential transmission member 551. Under the push of the radial component force of the differential transmission member 551, the front output connector 52 and the rear output connector 53 can only rotate synchronously with the differential transmission member 551, thereby achieving equal angular velocity rotation of the front output connector 52 and the rear output connector 53 (that is, the front output shaft 3 and the rear output shaft 4 rotate at the same angular velocity), thereby jointly driving the vehicle.

[0052] When the vehicle encounters an uneven road surface or turns, the front output shaft 3, the rear output shaft 4, and the input shaft 2 have different rotational speed requirements. For example, with the input connector 51 as a reference, the front output connector 52 and the rear output connector 53 have different rotational speed requirements relative to the input connector 51. When the front output connector 52 and the rear output connector 53 rotate in opposite directions, the differential transmission member 551 located in the first spiral groove and the differential transmission member 551 located in the second spiral groove move in the same direction along the axis (i.e., both move leftward / rightward), allowing the differential transmission member 551 to transmit power between the first and second spiral grooves. This allows the input connector 51, the front output connector 52, and the rear output connector 53 to rotate at different speeds (i.e., the input shaft 2, the front output shaft 3, and the rear output shaft 4 can rotate at different speeds), thus achieving a differential function.

[0053] At the same time, due to the rolling transmission of the differential transmission member 551, the front output connector 52 and the rear output connector 53 are subjected to very little force in the axial direction. That is, the front output connector 52 and the rear output connector 53 are in a free state in the axial direction, and the friction between them and the differential housing 54 is reduced to an extremely low level. The energy loss caused by friction is very small, thereby reducing energy consumption.

[0054] When the adhesion between one wheel of the vehicle and the ground decreases, that is, the first of the front output connector 52 and the rear output connector 53 is on a normal road surface and the second is on a slippery road surface, the rotational resistance torque received by the first is significantly greater than the rotational resistance torque received by the second. At this time, the differential transmission member 551 is subjected to uneven force in the axial direction. Under the push of the differential housing 54, the differential transmission member 551 tends to move toward the second wheel. The differential transmission member 551 will push the second wheel toward the end cover 57 or the partition ring 544 through the spiral groove on the second wheel, thereby squeezing the extrusion brake portion 56. The axial thrust provided by the differential transmission member 551 generates a large friction force between the second wheel and the differential housing 54. This friction force generates a rotational resistance torque, which has the effect of preventing the second wheel from rotating, thereby suppressing the rotation of the second wheel. This is the limited slip function.

[0055] If the friction between the second wheel and the differential case 54 is sufficiently strong, the second wheel cannot rotate despite the radial rotational torque of the differential drive member 551. This limited-slip state is fully locked. This limited-slip function effectively prevents the slipping wheel from spinning and losing power, thereby reducing energy loss. Furthermore, because the wheels do not slip, the vehicle's driving stability is greatly improved, reducing the risk of skidding and loss of control. This allows for quick escape in the event of a vehicle getting stuck.

Claims

1. A full-time four-wheel drive transfer case, comprising a case (1), wherein an input shaft (2), a front output shaft (3), a rear output shaft (4) and a differential (5) are rotatably arranged in the case (1), a front output shaft driving gear (31) is coaxially sleeved on the input shaft (2), a front output shaft driven gear (32) is coaxially fixedly connected to the front output shaft (3), the front output shaft driving gear (31) and the front output shaft driven gear (32) are connected to each other through a transfer case transmission member (33) to transmit power, characterized in that: An input connector (51), a front output connector (52) and a rear output connector (53) are provided inside the differential (5); the input shaft (2) is fixedly connected to the input connector (51) of the differential (5); the front output shaft driving gear (31) is slidably connected to the front output connector (52) of the differential (5); and the rear output shaft (4) is slidably connected to the rear output connector (53) of the differential (5).

2. The full-time four-wheel drive transfer case according to claim 1, characterized in that: The input shaft (2) is inserted into the rear output shaft (4), and a bearing or a sleeve is installed between one side of the input shaft (2) inserted into the rear output shaft (4) and the rear output shaft (4).

3. The full-time four-wheel drive transfer case according to claim 1, characterized in that: The transfer case transmission member (33) is a component for transmitting power at a constant speed.

4. The full-time four-wheel drive transfer case according to claim 3, characterized in that: The transfer case transmission member (33) is a chain or a gear.

5. The full-time four-wheel drive transfer case according to claim 1, characterized in that: The differential (5) includes a differential housing (54), the input connector (51) is a part of the differential housing (54), and the input connector (51) is fixedly connected to the external splines on the input shaft (2) through internal splines, so that the differential housing (54) and the input shaft (2) rotate at the same speed.

6. The full-time four-wheel drive transfer case according to any one of claims 1 to 5, characterized in that: The differential (5) is a limited slip differential or an open differential with a lock.

7. The full-time four-wheel drive transfer case according to claim 1, characterized in that: The outer wall of the front output connector (52) inside the differential (5) is provided with a first spiral groove (521), and the outer wall of the rear output connector (53) is provided with a second spiral groove (531), and the first spiral groove (521) and the second spiral groove (531) have opposite rotation directions.

8. The full-time four-wheel drive transfer case according to claim 7, characterized in that: The front output connector (52) and the differential housing (54), and the rear output connector (53) and the differential housing (54) are meshed and connected via a differential transmission assembly (55), so that the vehicle driving force is transmitted from the differential housing (54) to the front output connector (52) and the rear output connector (53) via the differential transmission assembly (55).

9. The full-time four-wheel drive transfer case according to claim 8, characterized in that: The differential housing (54) has a circulation loop (543), and the differential transmission members (551) of the differential transmission assembly (55) are closely attached to each other and fully distributed in the circulation loop (543).

10. The full-time four-wheel drive transfer case according to any one of claims 7 to 9, characterized in that: By engaging the first spiral groove (521) and the second spiral groove (531) with opposite rotation directions with the differential transmission assembly (55), differential motion is achieved among the input connector (51), the front output connector (52) and the rear output connector (53).

11. The full-time four-wheel drive transfer case according to claim 1, characterized in that: Four groups of extrusion brake parts (56) are provided inside the differential (5), and the extrusion brake parts (56) include a plurality of first friction plates (561) and a plurality of second friction plates (562). The horizontal component force transmitted to the first spiral groove (521) and the second spiral groove (531) through the differential transmission assembly (55) drives the front output connector (52) and the rear output connector (53) to approach the differential housing (54) respectively, and applies axial pressure to the extrusion brake parts (56) arranged between the front output connector (52) and the differential housing (54) and between the rear output connector (53) and the differential housing (54), so that the relative movement between the first friction plates (561) and the second friction plates (562) is blocked, thereby achieving the purpose of slip limitation.

12. A vehicle, characterized in that: The invention comprises a full-time four-wheel drive transfer case according to any one of claims 1 to 11.

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