JP3925818B2 - Drive transmission device for four-wheel drive vehicles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a drive transmission device for a four-wheel drive vehicle in which a viscous coupling is provided in a front drive system so that engine torque can be transmitted to front wheels.
[0002]
[Prior art]
Conventionally, as shown in FIGS. 5 and 6, in a drive transmission device for a four-wheel drive vehicle, the torque of the engine is directly connected by a gear, and a distributor distributes 1: 1 to the rear wheels through the front drive system and the rear drive system through the front drive system. It is structured to distribute at a rate of. Driving force or torque from the engine is transmitted to the input shaft 1 in the transfer 52 via the transmission. The input shaft 1 is rotatably supported by the transfer case 18 via a bearing. In the transfer case 18, the front drive shaft 2 of the front drive system, the rear drive shaft 3 of the rear drive system, and the counter shaft 17 are supported in parallel to the input shaft 1 via bearings so as to be rotatable in parallel. . A high main gear 4 and a low main gear 7 are rotatably supported on the input shaft 1. Further, a clutch hub 19 is fixed to the input shaft 1. A dog gear 14 is attached to the high main gear 4, and a dog gear 15 is attached to the low main gear 7. The clutch hub 19 is provided with a sleeve 11 for switching between a four-wheel drive high speed stage and a four-wheel drive low speed stage. When the sleeve 11 meshes with the dog gear 14, the high main gear 4 rotates, and when the sleeve 11 meshes with the dog gear 15, the low main gear 7 rotates.
[0003]
A high counter gear 5 that meshes with the high main gear 4 and a low counter gear 8 that meshes with the low main gear 7 are fixed to the counter shaft 17. A rear drive gear 6 is attached to the rear drive shaft 3, and a rear coupling 12 that connects the rear drive shaft 3 to the rear propeller shaft is attached. The rear drive gear 6 meshes with the high counter gear 5.
[0004]
A front drive gear 9 is rotatably supported on the front drive shaft 2 and a clutch hub 20 is fixed thereto. A front coupling 13 that connects the front drive shaft 2 to the front propeller shaft is attached to the front drive shaft 2. The front drive gear 9 is provided with a dog gear 16. The clutch hub 20 is provided with a sleeve 10 for switching between a four-wheel drive stage that drives the front wheels and a two-wheel drive stage that releases the drive of the front wheels. Therefore, if the sleeve 10 meshes with the dog gear 16, the rotation of the front drive gear 9 is transmitted to the front drive shaft 2 via the clutch hub 20.
[0005]
The drive transmission device for a four-wheel drive vehicle has the above-described configuration. When torque from the input shaft 1 is transmitted only to the rear drive shaft 3, the sleeve 10 is actuated to move the sleeve 10 to the dog gear. Release the mesh with 16. Therefore, when the sleeve 11 is engaged with the dog gear 14, the torque from the input shaft 1 is a high-speed rear drive system, that is, the input shaft 1 → clutch hub 19 → sleeve 11 → dog gear 14 → high main gear 4 → high. Counter gear 5 → rear drive gear 6 → rear drive shaft 3 → rear coupling 12 → rear propeller shaft → rear differential → rear wheel is transmitted. Alternatively, when the sleeve 11 is engaged with the dog gear 15, the torque from the input shaft 1 is low-speed rear drive system, that is, the input shaft 1 → clutch hub 19 → sleeve 11 → dog gear 15 → low main gear 7 → low. Counter gear 8 → counter shaft 17 → high counter gear 5 → rear drive gear 6 → rear drive shaft 3 → rear coupling 12 → rear propeller shaft → rear differential → rear wheel.
[0006]
Further, when the torque distribution from the input shaft 1 is transmitted to both the rear drive shaft 3 and the front drive shaft 2 at a ratio of 1: 1, the sleeve 10 is actuated to mesh the sleeve 10 with the dog gear 16. Therefore, when the sleeve 11 is engaged with the dog gear 14, the torque from the input shaft 1 is transmitted to the rear wheel through the high-speed rear drive system, and at the same time, the high-speed front drive system, that is, the input shaft 1 is used. -> Clutch hub 19-> sleeve 11-> dog gear 14-> high main gear 4-> high counter gear 5-> front drive gear 9-> dog gear 16-> sleeve 10-> clutch hub 20-> front drive shaft 2-> front coupling 13-> front propeller shaft-> front It is transmitted from the differential to the front wheels. Alternatively, when the sleeve 11 is engaged with the dog gear 15, torque from the input shaft 1 is transmitted to the rear wheels through the low-speed rear drive system, and at the same time, the low-speed front drive system, that is, the input shaft 1. → Clutch hub 19 → Sleeve 11 → Dog gear 15 → Low main gear 7 → Low counter gear 8 → Counter shaft 17 → High counter gear 5 → Front drive gear 9 → Dog gear 16 → Sleeve 10 → Clutch hub 20 → Front drive shaft 2 → Front It is transmitted to the coupling 13 → front propeller shaft → front differential → front wheel.
[0007]
Japanese Utility Model Laid-Open No. 62-103627 discloses a four-wheel drive vehicle. The four-wheel drive vehicle distributes and transmits power from the engine to the front wheels and the rear wheels, and an input side propeller shaft and an output side propeller shaft between the front and rear wheel axles by a center bearing member supported by the vehicle body. The center bearing member restricts the differential between the input side propeller shaft and the output side propeller shaft and absorbs the rotational difference when the output shaft side rotation exceeds the input shaft side rotation. It incorporates a dynamic limiting mechanism.
[0008]
[Problems to be solved by the invention]
However, in the drive transmission device for a four-wheel drive vehicle as described above, the engine torque is distributed equally between the front drive system and the rear drive system by the distributor. There may be a difference in load sharing between the front and rear wheels when the vehicle is empty and when the vehicle is loaded, and the dynamic load radius difference between the front and rear wheels may increase. In this case, if the drive transmission device of the four-wheel drive vehicle has a direct connection structure as described above, the rotational difference between the front and rear wheels cannot be absorbed, causing problems such as deterioration in fuel consumption and tire wear.
[0009]
Further, when the vehicle turns, a difference in rotational speed occurs between the front and rear wheels due to a difference in turning radius between the front and rear wheels. However, if the drive transmission device of the four-wheel drive vehicle has a direct connection structure as described above, the difference in rotational speed between the front and rear wheels. As it cannot absorb water, a steer brake phenomenon occurs.
[0010]
Further, when the drive transmission device of a four-wheel drive vehicle has a direct connection structure as described above, the front and rear drive force distribution, that is, torque distribution is 50:50, so the front drive system has almost the same strength as the rear drive system. Will be required. If the strength of the front drive system is increased, the front drive system, especially the front differential, will become larger and lighter, making it difficult to reduce the weight of the front drive system. Problems such as stroke reduction occur, and the ride quality also deteriorates.
[0011]
By the way, as a front wheel suspension device for suspending a front wheel, a device as shown in FIG. 3 is known. The front wheel suspension device is configured as an independent suspension device, and the front drive system is configured such that the front wheel 31 is driven from the front differential 30 through the front drive shaft 35. An upper link 33 and a lower link 34 are attached to a knuckle 37 provided on the front wheel 31 via a king pin 38. As for the independent suspension device, the upper link 33 is attached to the vehicle body frame via the shock absorber 32, and the front differential 30 is supported and fixed to the floor of the vehicle.
[0012]
[Means for Solving the Problems]
An object of the present invention is to solve the above-mentioned problem, and a viscous coupling is incorporated in the front drive system so that the engine torque is transmitted to the front wheels, and the viscous coupling is always slipped without being directly connected. With a no-hump characteristic, the torque distribution to the front wheels is always smaller than the torque distribution to the rear wheels, and when a driving condition such as slipping of the rear wheels occurs, a part of the engine torque is It is an object to provide a drive transmission device for a four-wheel drive vehicle that can be distributed to front wheels and assisted to enable smooth driving of rear wheels.
[0013]
The present invention includes an input shaft that transmits engine torque, a front drive system that includes a front differential that transmits the torque from the input shaft to the front wheels, and a rear differential that transmits the torque from the input shaft to the rear wheels. In a drive transmission device for a four-wheel drive vehicle comprising a rear drive system,
Wherein the front drive system, the viscous coupling that is configured and Nohanpu characteristics can torque distribution in accordance with the difference in rotational speed between the front wheel and the rear wheel of the four-wheel drive vehicle is provided Nohanpu of the viscous coupling four torque limit value in the characteristic, characterized in that the said torque distribution values of the front drive system is set smaller than the torque distribution values to the rear drive system when the torque distribution to the front drive system The present invention relates to a drive transmission device for a wheel drive vehicle.
[0014]
The front drive shaft before SL front driving system, the linked via the counter gear from fixed main gear to the input shaft while rotatably supporting a front drive gear, the inner case is the front of the viscous coupling Connected to the drive shaft, the outer case of the viscous coupling is connected to the front drive gear.
[0015]
Furthermore, in the drive transmission device of this four-wheel drive vehicle, the front wheel suspension device for suspending the front wheel is configured as an independent suspension device.
[0016]
As described above, in the drive transmission device for a four-wheel drive vehicle, the viscous coupling can distribute torque to the front drive system in accordance with the rotational speed difference between the front wheel and the rear wheel of the four-wheel drive vehicle. Is incorporated, and the viscous coupling is adjusted to a no hump that does not become a direct coupling state (ie, a hump) due to the lock. Further, the viscous coupling functions as a torque limiter and a fluid clutch for distributing torque to the front wheels, and the torque distribution to the rear drive system is set to be larger than the torque distribution of the front drive system through the viscous coupling. The torque distribution of the rear wheels can be set to a value that is always larger than the torque distribution of the front wheels, for example, 5 to 8 times. Accordingly, the front drive system does not require great strength, and can be significantly reduced in size as compared with the rear drive system. In particular, the front differential in the front drive system can be reduced in size, and the front propeller shaft and the can configure front drive shaft diameter, the Re its, to achieve weight reduction, suppressing the increase of the vehicle height, can be configured lowered passenger compartment height, be close to the occupant getting on and off of the two-wheel drive vehicle Can do.
[0017]
Further, when the drive transmission device of this four-wheel drive vehicle is used and the front wheel suspension device for suspending the front wheel is configured as an independent suspension device, the floor base of the passenger compartment can be further lowered, and the four-wheel drive vehicle as a small cabover This floor base can be configured in the same manner as the floor base of a two-wheel drive vehicle, and can be housed in a small vehicle frame, and a sufficient stroke amount of the front suspension can be secured to improve riding comfort.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a drive transmission device for a four-wheel drive vehicle according to the present invention will be described below with reference to the drawings. FIG. 1 is a schematic explanatory view for explaining an embodiment of a drive transmission device for a four-wheel drive vehicle according to the present invention, and FIG. 2 is a sectional view showing an embodiment of a drive transmission device for a four-wheel drive vehicle according to the present invention. . 1 and 2, the same components as those in FIGS. 3 to 5 are denoted by the same reference numerals.
[0019]
In the drive transmission device for this four-wheel drive vehicle, the driving force, that is, torque from the engine 50 arranged on the front wheel 31 side is transmitted from the transmission 51 to the input shaft 1 in the transfer 52. In the transfer case 18, a main gear 21, a counter gear 22, a front drive gear 9 and a viscous coupling 23 constituting a transfer 52 are accommodated in order to distribute torque from the engine 50 to the front drive system and the rear drive system. ing. This drive transmission device for a four-wheel drive vehicle includes an input shaft 1 to which torque of the engine 50 is transmitted, a front drive system having a front differential 30 that transmits torque from the input shaft 1 to the front wheels 31, and torque from the input shaft 1. It is comprised from the rear drive system provided with the rear differential 40 which transmits this to the rear-wheel 41.
[0020]
In this four-wheel drive vehicle drive transmission device, the torque transmitted to the input shaft 1 is transmitted through the rear propeller shaft 39 when there is no difference in rotational speed between the front wheels 31 and the rear wheels 41 (the rear wheels 41 slip). It is transmitted to the rear differential 40 and transmitted from the rear differential 40 to the rear wheels 41 on both sides through the rear drive shaft 53. In addition, when the torque transmitted to the input shaft 1 has a difference in rotational speed between the front wheel 31 and the rear wheel 41 (sliding on the rear wheel 41), the torque corresponding to the slip is converted into the main gear 21, the counter gear 22 and the front gear. The torque transmitted to the drive gear 9 and transmitted to the front drive gear 9 is distributed to the front drive shaft 2 by the torque coupling 23 and transmitted to the front drive shaft 2. The torque distributed to the front drive shaft 2 is transmitted to the front propeller shaft 29 through the front propeller shaft 29. Is transmitted to the differential 30. The torque transmitted to the front differential 30 is transmitted to the front wheels 31 on both sides through the front drive shaft 35 and the joint 49.
[0021]
This drive transmission device for a four-wheel drive vehicle is a viscous cup that is capable of distributing torque according to the rotational speed difference between the front wheels 31 and the rear wheels 41 of the four-wheel drive vehicle and having no hump characteristics, particularly in the front drive system. A ring 23 is provided, and the torque distribution of the front drive system is always set smaller by the viscous coupling 23 than the torque distribution to the rear drive system. That is, the viscous coupling 23 has a no-hump characteristic tuned, and has a function as a torque limiter and a fluid clutch, and is incorporated in series in the front drive system.
[0022]
In this drive transmission device for a four-wheel drive vehicle, the input shaft 1, the counter shaft 17 and the front drive shaft 2 are rotatably supported by a transfer case 18 via bearings. A main gear 21 and a rear coupling 12 are fixed to the input shaft 1. The front drive gear 9 includes a dog gear 16 and is rotatably supported by the front drive shaft 2. An inner case 25 of a viscous coupling 23 is fixed to the front drive shaft 2. The sleeve 10 is provided in the outer case 24 of the viscous coupling 23 so as to be slidable so as to be engaged with or released from the dog gear 16. In the viscous coupling 23, silicon oil 26 is sealed in a chamber formed by the outer case 24 and the inner case 25, and an outer plate 27 erected on the outer case 24 and an inner plate erected on the inner case 25 in the chamber. 28 is arranged.
[0023]
The counter gear 22 fixed to the counter shaft 17 meshes with the main gear 21 and meshes with the front drive gear 9. The front drive shaft 2 in the front drive system is connected via a counter gear 22 from a main gear 21 fixed to the input shaft 1 to rotatably support the front drive gear 9, and an inner case 25 of a viscous coupling 23 is connected to the front case. The outer case 24 of the viscous coupling 23 is connected to the drive shaft 2 and is connected to the front drive gear 9 via the sleeve 10 and the dog gear 16.
[0024]
Transmission of torque in the transfer 52 of the drive transmission device of this four-wheel drive vehicle is as follows. That is, when the sleeve 10 is not engaged with the dog gear 16 and is in the released state, the torque from the engine 50 is not distributed by the viscous coupling 23 and is transmitted only to the rear drive system without being transmitted to the front drive system. Is done. Therefore, the torque from the engine 50 is transmitted to the rear wheel 41 through the path of the input shaft 1 → the rear coupling 12 → the rear propeller shaft 39 → the rear differential 40 → the rear drive shaft 53 → the rear wheel 41. The drive transmission device of the four-wheel drive vehicle, that is, the vehicle is in a two-wheel drive state.
[0025]
When the sleeve 10 is engaged with the dog gear 16, the torque from the engine 50 is distributed by the viscous coupling 23 and is distributed to the front drive system and the rear drive system. When the vehicle does not have a difference in rotational speed between the front wheel 31 and the rear wheel 41, the viscous coupling 23 has an outer plate 27 fixed to the outer case 24 and an inner case 25 fixed to the inner case 25. There is no rotational difference with the plate 28, no shearing force is applied to the silicone oil 26, most torque is distributed to the rear drive system, and almost no torque is distributed to the front drive system. Is a two-wheel drive state.
[0026]
In this drive transmission device for a four-wheel drive vehicle, if the rear wheel 41 exceeds the rotational speed of the front wheel 31 or the front wheel 31 or the rear wheel 41 slips due to loading on the vehicle, a rotational speed difference occurs between the two. A rotational difference is generated between the outer plate 27 and the inner plate 28 of the viscous coupling 23, and a shearing force acts on the silicon oil 26, and torque distribution to the front drive system and the rear drive system of the viscous coupling 23 is achieved. The function is activated and the vehicle is in a four-wheel drive state. That is, transmission of torque in the rear drive system is transmitted to the rear wheel 41 through the path of the input shaft 1 → the rear coupling 12 → the rear propeller shaft 39 → the rear differential 40 → the rear drive shaft 53 → the rear wheel 41. Also, torque transmission in the front drive system is as follows: input shaft 1 → main gear 21 → counter gear 22 → front drive gear 9 → dog gear 16 → sleeve 10 → viscous coupling 23 → front drive shaft 2 → front propeller shaft 29 → front differential 30 → the front drive shaft 35 → the joint 49 → the front wheel 31 is transmitted to the front wheel 41 through a route.
[0027]
In this drive transmission device for a four-wheel drive vehicle, as described above, the viscous coupling 23 does not distribute torque to the front drive system and is in a two-wheel drive state during steady running of the vehicle. When a slip state occurs in 41, the viscous coupling 23 performs the torque distribution function between the front drive system and the rear drive system, and distributes the minimum necessary torque to the front wheels 31. Thus, the smooth running of the vehicle can be assisted. Further, when the relative rotational difference between the front wheel 31 and the rear wheel 41 is small, the shearing force of the viscous coupling 23 against the silicon oil 26 is also small, so that the viscous coupling 23 also acts as a fluid clutch.
[0028]
Further, although not shown in the figure, the drive transmission device for the four-wheel drive vehicle can be fixed to the front drive shaft 2 of the front drive system, and the front drive gear 9 is fixed to the input shaft 1. Torque is transmitted from the main gear 21 through the counter gear 22. In this case, the viscous coupling is configured to be incorporated in the front differential. Thereby, in the drive transmission device of this four-wheel drive vehicle, the torque distribution to the rear drive system can be set larger than the torque distribution of the front drive system by viscous coupling.
[0029]
In this drive transmission device for a four-wheel drive vehicle, as shown in FIG. 3, the front wheel suspension device for suspending the front wheel 31 is configured as an independent suspension device 43. FIG. 4 is a side view of the cab 47 of the present invention and the conventional cab 48. 4 (a) shows a cab-over type cab 47 incorporating the drive transmission device of this four-wheel drive vehicle, and FIG. 4 (b) shows a conventional cab 48. ing. In this drive transmission device for a four-wheel drive vehicle, since the front differential 30 can be made smaller than the conventional front differential 42, the front differential 30 is installed in a space on the side of the engine 50 as shown in FIG. can, as shown in FIG. 4 (b), of the passenger compartment based the height H ₁ can be configured low, it can be in a three-seat passenger's seat with a margin. On the other hand, as shown in FIG. 4 (b), the conventional direct drive transmission device for a four-wheel drive vehicle is configured to be large in terms of strength, making it difficult to reduce the weight. not only, the higher the passenger compartment base of the height H _2, can not be formed of the passenger seat in the middle, it becomes impossible three people ride, worse occupant of getting on and off of, the stroke reduction, such as the front suspension problem Will occur.
[0030]
【The invention's effect】
As described above, the drive transmission device for a four-wheel drive vehicle according to the present invention incorporates a viscous coupling having no hump characteristics in the front drive system, so that the drive force of the front drive system is always higher than the drive force of the rear drive system. by limiting the yet small torque, it can be miniaturized to the front driving system, allowing weight reduction. Since the front drive system can be reduced in size, the height of the passenger seat can be lowered while the vehicle is a four-wheel drive vehicle, and the suspension stroke can be sufficiently secured, so that the same level of ease of getting on and off as a two-wheel drive vehicle can be secured. Furthermore, since the front drive system can be miniaturized, it is possible to provide a small vehicle frame, that is, a total vehicle height, a three-seater ride, and a four-wheel drive vehicle that can carry 2 tons. Since the viscous coupling functions as a clutch, the steering brake phenomenon during turning during four-wheel drive traveling can be eliminated.
[0031]
Further, in the drive transmission device for a four-wheel drive vehicle, the viscous coupling acts as a fluid clutch, so that tire wear during four-wheel drive travel can be suppressed, and fuel consumption can be improved. In addition, the drive transmission device for the four-wheel drive vehicle can be constructed in a smaller size as compared with the direct-coupled drive transmission device for the conventional four-wheel drive vehicle, so that the front wheel suspension device for suspending the front wheel is independent. When the suspension device is configured, it is possible to allow three people to ride with a sufficient margin due to the space of the front differential.
[Brief description of the drawings]
FIG. 1 is a schematic explanatory view illustrating an embodiment of a drive transmission device for a four-wheel drive vehicle according to the present invention.
FIG. 2 is a cross-sectional view showing an embodiment of a drive transmission device for a four-wheel drive vehicle according to the present invention.
FIG. 3 is a partial rear view showing an independent suspension device of a front drive system applied to the drive transmission device of this four-wheel drive vehicle.
FIG. 4 is a side view showing a cab over type cab incorporating a drive transmission device for this four-wheel drive vehicle and a conventional cab.
FIG. 5 is a developed cross-sectional view showing an example of a drive transmission device of a conventional four-wheel drive vehicle.
6 is an explanatory diagram showing a gear meshing relationship in the drive transmission device of the four-wheel drive vehicle of FIG. 4; FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Input shaft 2 Front drive shaft 9 Front drive gear 21 Main gear 22 Counter gear 23 Viscous coupling 24 Outer case 25 Inner case 27 Outer plate 28 Inner plate 30 Front differential 31 Front wheel 40 Rear differential 41 Rear wheel 43 Independent suspension device 50 Engine

Claims (3)

An input shaft that transmits engine torque, a front drive system that includes a front differential that transmits the torque from the input shaft to the front wheels, and a rear drive that includes a rear differential that transmits the torque from the input shaft to the rear wheels In the drive transmission device of a four-wheel drive vehicle consisting of
The front drive system is provided with a viscous coupling that can distribute torque according to a difference in rotational speed between the front wheel and the rear wheel of the four-wheel drive vehicle and has no hump characteristics. The four-wheel vehicle characterized in that the torque distribution value of the front drive system when a torque limit value in characteristics is distributed to the front drive system is set smaller than the torque distribution value to the rear drive system Drive transmission device for driving car. A front drive shaft of the front drive system is connected via a counter gear from a main gear fixed to the input shaft to rotatably support the front drive gear, and an inner case of the viscous coupling is attached to the front drive shaft. The drive transmission device for a four-wheel drive vehicle according to claim 1, wherein the outer case of the viscous coupling is connected to the front drive gear. The drive transmission device for a four-wheel drive vehicle according to claim 1 or 2 , wherein the front wheel suspension device for suspending the front wheel is an independent suspension device.

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