JPH0248233A - Four-wheel drive vehicle of mid ship type - Google Patents

Abstract

PURPOSE:To optimize distribution of weight of front and rear wheels approximately equal by locating a heavy speed change gear, a center differential device, etc. on the side of front wheels. CONSTITUTION:A speed change gear 25 and a center differential device 30 is integrated into a case 21 and provided vertically at the rear of a front differential device 20 on a center line of a vehicle of a front wheel shaft. A propeller shaft 8 is constituted in a triple pipe structure whereby a hollow rear drive shaft 39 and an outermost pipe 40 are loosely fitted into a center propeller shaft 8. A side gear 34 of the center differential device 30 is connected to a rear drive shaft 39 via a pair of a reduction drive gear 37 and a reduction driven gear 38, and a front and rear driving system is coupled in an integrated rigid structure on said rear drive shaft 39 between a transfer case 10 and the case 21.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a mid-engine four-wheel drive vehicle in which the engine is located in the center of the vehicle, and more particularly to a layout and rigid structure that takes into account weight distribution between the front and rear wheels of the drive system.

[Conventional technology]

A mid-ship type vehicle has an engine mounted in the center of the vehicle behind the driver, and a clutch, transmission, and rear differential are directly connected to the engine via a rigid transaxle. On the other hand, when converting this type of vehicle to four-wheel drive, for example, a center differential device is additionally added, but this center differential device is attached to the output side of the transmission and separates one of the two divided outputs from the other. is configured to be transmitted to each front and rear differential device. Regarding the drive system in which the drive system is distributed, for example, there is a prior art disclosed in Japanese Unexamined Patent Publication No. 139808/1983. In front-engine, rear-drive (FR) vehicles, it has been shown that the transmission is integrated with the rear differential device, and the clutch housing and transmission case are made into an integral rigid structure with a torque tube coaxial with the propeller shaft. ing.

[Problem to be solved by the invention]

By the way, according to the drive system layout of the conventional midship type four-wheel drive vehicle mentioned above, the clutch, transmission,
Since the center differential device etc. are arranged centrally, the weight distribution between the front and rear wheels is too close to the rear wheels.For this reason, even in a 4-wheel drive vehicle, the grip force between the front and rear wheels differs depending on the weight distribution. , the original performance of 4-wheel drive cannot be demonstrated. For this reason, it is desirable to appropriately distribute each device of the drive system to the front and rear wheels so that the weight distribution between the front and rear wheels is equalized. On the other hand, distributing the drive system complicates assembly, causing vibration noise and
Since this is disadvantageous in terms of rigidity, etc., it is necessary to make the drive system in a distributed arrangement state a rigid structure. However, in the case of a midship type four-wheel drive vehicle with a center differential, the power distribution is completely different from that of an FR vehicle, and the above-mentioned prior art cannot be applied as is. The present invention has been made in view of the above points, and its purpose is to optimize the front and rear wheel weight distribution by the drive system, and to create a mid-ship type four-wheel system that can be integrated into a rigid structure. Our goal is to provide driving vehicles.

[Means to solve the problem]

In order to achieve the above object, the midship type four-wheel drive vehicle of the present invention has an engine mounted at a position behind the driver in the center of the vehicle, and a midship type drive system in which a clutch is directly connected to the engine and a rear differential device is integrally connected.
A transmission and a center differential device are integrally arranged in a front differential device on a front axle, a propeller shaft from the clutch is configured to be transmitted to the center differential device via the transmission, and one of the center differential devices The output side of the is connected to the front differential device through the front drive shaft, and the other output side is connected to the rear differential through the reduction gear, the rear drive shaft coaxial with the propeller shaft, and the transfer device disposed close to the engine. The engine side and the speed change flfilFI are connected to an integral rigid structure by an outermost pipe coaxial with the propeller shaft.

[For production]

Based on the above configuration, a clutch and a rear differential device 1 transfer device are integrally arranged in the engine mounting portion behind the driver near the rear wheels, and a transmission is provided on the front wheel side. By distributing and distributing the center differential device and front differential device, and by routing transmission between them, it is possible to achieve an optimal weight distribution between the front and rear wheels, which is approximately equal. The vehicle will be able to fully demonstrate the performance of four-wheel drive. In addition, the engine side and the transmission l1lPl, which are distributed in the front and rear, can transmit power through a propeller shaft, a rear drive shaft, and a pipe with a triple tube structure, and are connected to a rigid structure to form an integrated drive system f! This makes it possible to improve ease of assembly and reduce vibration and noise.

【Example】

Hereinafter, one embodiment of the present invention will be described based on the drawings. In FIG. 1, the outline of the mid-ship type 4VA drive vehicle of the present invention will be described. Reference numeral 1 is the vehicle, 2 is the front wheel, and 3 is the front wheel.
is a rear wheel, and a horizontally opposed engine 4 with a low center of gravity is mounted vertically in front of the rear axle behind the driver on the center line of the vehicle, with the horizontally opposed engine 4 having a low center of gravity. A clutch 6 is housed in a clutch housing 5 immediately in front of the engine 4, connected to a crankshaft 7, and a propeller shaft 8 extends forward from the hub side of the clutch 6. A transfer gear 10 is attached between the front of the clutch housing 5 and the lower engine oil pan 9, a transfer device 11 is provided inside the transfer gear 10, and a differential carrier 1 is installed at the rear of the engine 4.
6 is provided in a protruding manner, and a rear differential device 17 is provided inside the differential carrier 16. The transfer device 11 has a groper shaft 8 as shown in FIG.
The gear 12 loosely fitted into the gear 1 is connected to the gear 1 via the idler gear 13.
A transfer shaft 15, which is integral with the gear 14, extends rearward through the oil pan 9. The drive pinion 1 at the rear end of the transfer shaft 15
8 meshes with the ring gear 19 of the rear differential device 17 to form a transmission structure. On the other hand, behind the front differential device 20 on the vehicle center line of the front axle is a transmission 25. A center differential device 30 is housed in an integrated case 21 and arranged vertically. gear shift tl
II 25 is an input shaft 26 . connected in a straight line in front of the propeller shaft 8 as shown in FIG. 2 . It has a hollow output shaft 27 parallel to it, and a plurality of sets of transmission gears 28 and synchronizing mechanisms 29 are installed between these input shafts 26 and output shafts 27 to output transmission power to the output shaft 27. It is something. The center differential device 30 is a bevel gear type, and the output shaft 2
A side gear 33.3 is connected to a pinion 32 of a differential case 31 which is disposed at the rear coaxially with the output shaft 27 and is integrally connected to the output shaft 27.
4 mesh to absorb the difference in rotation between the front and rear wheels, and distribute and output torque according to the weight distribution between the front and rear wheels. Further, between the differential case 31 of the center differential device 30 and one of the side gears 33, there is a differential limiting device 35 of a dog clutch type manual type, a viscous coupling, a hydraulic multi-disc clutch, or a single friction clutch type automatic type. , arranged to act as a differential lock. One side gear 33 is connected to a front drive shaft 36 that passes through the inside of the output shaft 27, and a drive pinion 22 at the front end of this front drive shaft 36 meshes with the ring gear 23 of the front differential device 20 to form a transmission structure. Ru. On the other hand, the propeller shaft 8 portion has a hollow rear drive shaft 39. fi outer pipes 40 are loosely fitted on the same axis to form a triple pipe supplement, and the side gears 34 of the center differential device 30 are connected to one set of ducting drive gears 31. It is connected to a rear drive shaft 39 via a reduction gear 38, and the above-described transfer device 11 is connected to this rear drive shaft 39. The pipe 40 is
The front and rear drive systems are connected to an integral rigid structure between the transfer case 10 and the case 21. In this way, the clutch 6 is mounted on the mounting part of the rear engine 4.
Transfer device 11. A rear differential device 17 is integrally arranged, and a front differential device 20° transmission 25. A center differential device 30 and the like are integrally arranged, and a driver is placed between them. Here, the center of gravity is set at the center between the front wheels 2 and the rear wheels 3 due to the weight of the front and rear distributed drive systems, etc.
Front wheel 2. The weight distribution between rear wheels 3 is 5:5. Next, the operation of the four-wheel drive vehicle having such a configuration will be described. First, the power of the engine 4 is transmitted through the clutch 6 and the propeller shaft 8.
The transmission power is transmitted forward through the transmission gear 28 and input to the input shaft 26 of the transmission 5125, and the transmission power is transmitted to the differential case 31 of the center differential device 30 via the output shaft 27 by the transmission gear 28 and the synchronization mechanism 29. The binion 32 and the side gears 33 and 34 absorb the difference in rotation between the front and rear wheels while distributing half the torque to both the side gears 33 and 34, and the power from one side gear 33 is transferred to the front drive shaft 36. Front # via front differential device 20 etc.
Transmit to a2. The power of the other side gear 34 is
Reduction drive gear 37. Reduction driven gear 38. Rear drive shaft 39. Transfer device 11
gears 12 to 14 and transfer shaft 15. Rear differential equipped! 17 etc. to the rear wheels 3 for four-wheel drive driving. Here, the weight distribution between front wheel 2 and rear wheel 3 is 5=5,
Since the torque distribution by the center differential device 30 is equal to this, the driving force between the front wheels 2 and the rear wheels 3 becomes equal, and the four-wheel drive performance is maximized. Each part of the drive system is housed in a transfer case 10° case 21, and a propeller shaft 8. Rear drive shaft 39
The vibration noise is also reduced by being accommodated within the pipe 40. Note that the engine 4 is not limited to a horizontally opposed type, and the center differential device 30 may be of a planetary gear type.

【Effect of the invention】

As described above, according to the present invention, in a midship type four-wheel drive vehicle, the heavy transmission, center differential device, etc. are distributed to the front wheels, and the front and rear wheel weight distribution is optimized. Wheel drive performance can be improved. Furthermore, since the propeller shaft portion has a triple tube structure and the drive system has a rigid structure, it is possible to improve the ease of assembly by integral mounting, simplify the structure of the drive system, and reduce noise. Furthermore, since the drive system is arranged inside the front and rear wheels and the yawing moment of inertia is reduced, yawing motion performance is improved. Moreover, since the rolling moment of inertia can be reduced by the central arrangement of the drive system in the longitudinal direction, the motion performance accompanying roll motion is improved.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of a midsig type four-wheel drive vehicle according to the present invention, and FIG. 2 is an enlarged sectional view of the main parts.

Claims (1)

[Scope of Claims] In a mid-ship drive system in which an engine is mounted behind the driver in the center of the vehicle, a clutch is directly connected to the engine, and a rear differential device is integrally connected, the front differential device on the front axle is equipped with a transmission and a center transmission. A propeller shaft from the clutch is configured to be transmitted to the center differential device via the transmission, and one output side of the center differential device is connected to the front drive shaft via the front drive shaft. Connect the other output side to the differential gear and connect it to the reduction gear.
Transmission is configured to the rear differential device via a rear drive shaft coaxial with the propeller shaft and a transfer device disposed close to the engine, and an outermost pipe coaxial with the propeller shaft connects the engine side and the transmission. A mid-engine 4-wheel drive vehicle characterized by its sides being joined into an integrated rigid structure.