JPH0478502B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a four-wheel drive vehicle equipped with a so-called horizontally mounted engine whose crankshaft is arranged so as to extend in the left-right direction of the vehicle body.

(Prior art) Generally, in a four-wheel drive vehicle, the engine is arranged so that its crankshaft extends in the longitudinal direction of the vehicle body, and the transmission is arranged so that its input shaft and output shaft extend in the longitudinal direction of the vehicle body. death,
A transfer is added to the transmission, which divides the engine's driving force into two between the front propeller shaft and the rear propeller shaft, transmitting it to the front differential and rear differential, and transmits it to the front, rear, left, and right wheels. What drives it is known.

However, four-wheel drive vehicles with such vertically mounted engines have the problem of not being able to provide a large cabin space, so in recent years, four-wheel drive vehicles with transversely mounted engines that do not have this problem have been developed.
Several wheel drive vehicles have been proposed.

For example, a center differential consisting of a group of planetary gears is installed coaxially with the front differential, and the output from the transmission is received by the pinion carrier of the center differential, and the driving force is applied to the rear wheel drive shaft from the ring gear or sun gear of the center differential. (Refer to Japanese Patent Application Laid-Open No. 154328/1982), or the output from the transmission is received by the ring gear of the center differential and sent from the pinion carrier of the center differential to one of the pair of bevel gears. There is a method (see Japanese Patent Laid-Open No. 57-41216) that outputs the same.

(Problem to be Solved by the Invention) However, with this configuration, there is a problem in that the positional relationship between the center differential and the pair of bevel gears that transmit driving force to the rear wheel drive shaft is restricted by the front differential. .

The main object of the present invention is to dispose a center differential in a four-wheel drive vehicle and one of a pair of bevel gears for rear wheel drive coaxially, and to offset the front differential with respect to the center differential. The object of the present invention is to expand the degree of freedom in the layout of a center differential and a pair of bevel gears without being influenced by the above, and to reduce power transmission loss by shortening a power transmission path.

However, in that case, there is the following problem. That is, in general, it is desired that the front differential be placed near the left and right center of the vehicle body in order to equalize the torsional torque to the front wheel drive shaft, and the layout is such that the front differential is offset from the center differential as described above. This can be achieved with However, with this offset arrangement, it becomes necessary to arrange a drive gear coaxially with the center differential for transmitting power from the center differential to the front differential, which increases the shaft length of the center differential.

On the other hand, when attempting to engage the center differential directly with the output gear of the transmission to achieve deceleration, the center differential must be placed adjacent to the transmission, and the propeller shaft that transmits power to the rear wheels must be placed adjacent to the transmission. Due to its relationship with the tunnel section of the vehicle floor, it must be located in the left and right center of the vehicle body.Furthermore, if the center differential is provided with a differential limiting mechanism that limits its differential movement, it must be located coaxially with and adjacent to the center differential. Because of the desirability of this position, there is a demand for shortening the length of the shaft portion of the center differential.
Therefore, a contradictory problem arises when arranging the drive gear coaxially with the center differential.

An object of the present invention is to provide a front differential with an offset position relative to the center differential.
By specifying the configurations of the center differential and front differential, the aim is to shorten the shaft length of the center differential and solve the above problems at once.

(Means for Solving the Problem) In order to achieve the above object, the solving means of the present invention includes an engine arranged such that the crankshaft extends in the left-right direction of the vehicle body, an output shaft having an input shaft and a drive gear. transmissions arranged in the left and right direction of the vehicle, a center differential that receives power from the output shaft of the transmission and distributes it to the front wheels and rear wheels, and a center differential that receives power from the center differential and distributes it between the left and right front wheels. It is equipped with a front differential that distributes power to the wheels. The center differential includes a planetary gear mechanism having a ring gear, a sun gear, a planetary pinion, and a pinion carrier that supports the planetary pinion, and the ring gear directly meshes with a drive gear of an output shaft of the transmission and reduces the power from the output shaft. The sun gear and pinion carrier are two output gears that output power to the front wheels and the rear wheels, respectively. The front differential is formed of a bevel gear mechanism, the shaft center of which is offset from the center differential, and has an input gear for inputting power from one of the output gears of the center differential. It further includes a pair of bevel gears for transmitting driving force to the rear wheel drive shaft, one of the bevel gears being disposed coaxially with the center differential and configured to be integrally fixed to the other output gear of the center differential. shall be

(Function) Accordingly, in the present invention, by offsetting the center differential and the front differential, the degree of freedom in layout is expanded. Additionally, the center differential also functions as a reduction gear, and by laying out a bevel gear coaxially with it that transmits power to the rear wheels, the power transmission path becomes shorter.

In addition, since the center differential is configured with a planetary gear mechanism, its axial length (width) is reduced, and while the length of the shaft portion of the center differential is shortened, the drive gear for transmitting power from the center differential to the front differential is can be placed coaxially with the center differential. On the other hand, since the front differential is offset from the center differential, there are fewer restrictions in the width direction, and an inexpensive bevel gear mechanism can be used, which reduces costs.

(Example) Examples of the present invention will be described below with reference to the drawings.

<Example 1> In FIGS. 1 and 2, reference numeral 1 denotes an engine in a four-wheel drive vehicle, and a crankshaft 2 is arranged at the front of the vehicle body so as to extend in the left-right direction of the vehicle body. Reference numeral 3 denotes a transmission, which is disposed within a casing 4 and includes an input shaft 6 to which the crankshaft 2 is connected via a clutch means 5, and an output shaft 8 linked to a center differential 7. They are placed on the left and right sides of the vehicle.

The input shaft 6 is provided with a first speed gear 9, a reverse gear 10, and a second speed gear 1 from the clutch means 5 side.
1, a third speed gear 12, and a fourth speed gear 13 are fixedly installed in this order. On the other hand, the output shaft 8 has a gear 1 that meshes with each of the gears 9, 10, 11, 12, and 13.
4, 15, 16, 17, 18 and a drive gear 19 are fixedly installed, and gears 14, 15, 17, and 1
Synchronizing mechanisms 20 and 21 are arranged between the two.

The center differential 7 is supported by a ring gear 22 as an input gear that directly meshes with the drive gear 19 of the output shaft 8 of the transmission 3 and is driven while decelerating the power from the output shaft 8, and a pinion carrier 23. A planetary pinion 2 as one of the output gears meshing with the ring gear 22
4 and a sun gear 25 as one of the output gears meshing with the planetary pinion 24.
The planetary pinion 24 is a double pinion type composed of a pair of pinions 26 and 27 that mesh with each other, one pinion 26 is connected to the ring gear 22, and the other pinion 27 is connected to the sun gear 25.
They mesh with each other.

Reference numeral 28 denotes a front differential consisting of a bevel gear mechanism, and its axis is offset from the center differential 7. A transmission gear 30 is integrally provided on the outer periphery of the front differential case 29 of the front differential 28, and the transmission gear 30 meshes with a drive gear 31 coaxial with and integrally connected to the sun gear 25 of the center differential 7. Also, inside the front differential case 29, a pair of bevel gears 33 and 34 are arranged opposite to each other by a short axis 32 in the longitudinal direction of the vehicle body.
A group of bevel gears is provided which includes another pair of bevel gears 35 and 36 which are disposed opposite to each other on the left and right so as to mesh with the pair of bevel gears 33 and 34.

A linkage mechanism 37 of a pair of left and right bevel gears 35, 36,
One end of the front wheel drive shafts 41, 42 is connected to the outer end of the front wheel drive shaft 41, 42 via joints 39, 40, and another joint 4 is connected to the other end of the front wheel drive shaft 41, 42.
3 and 44 to left and right front wheels 45 and 46, respectively.

A first shaft 47 formed integrally with the pinion carrier 23 of the center differential 7 has a bearing 48 at the end opposite to the drive gear 31 with respect to the center differential 7.
The second shaft 49 is rotatably connected to the second shaft 49 via the second shaft 49 . A 2-4 switching sleeve 50 is spline-fitted to the connecting portion between the shafts 47 and 49 so as to be movable in the axial direction. This 2-4 switching sleeve 50 can be operated between both shafts 4 by an operating means (not shown).
7 and 49 are connected and rotated synchronously, and a two-wheel drive position where only the first shaft 47 is spline-fitted. still,
In the two-wheel drive position, the rear differential 51 and both rear wheels 5
2, 53 is released, and the members between the first shaft 47 and both rear wheels 52, 53 do not move.

Further, a bevel gear 54 coaxial with the center differential 7 is fitted and fixed on the second shaft 49.
At the front end of the propeller shaft 55, there is a joint 5.
6 is in mesh with another bevel gear 57 provided therebetween. Drive force is transmitted to rear wheel drive shafts 58, 59 by these pair of bevel gears 54, 57.

A bevel gear 61 of a rear differential 51 is connected to the rear end of the propeller shaft 55 via a joint 60. This bevel gear 61 has a pair of bevel gears 6
A large bevel gear 64 supporting gears 2 and 63 meshes,
Another pair of bevel gears 65 and 66 are disposed oppositely on the left and right so as to mesh with the bevel gears 62 and 63. The left and right bevel gears 65 and 66 have joints 67 and 68.
One end of the rear wheel drive shafts 58, 59 is connected to the other end of the drive shaft 58, 59 via a joint 6.
The left and right rear wheels 52, 53 are connected via 9, 70.

A differential sleeve 71 is movably spline-fitted to the first shaft 47 formed integrally with the pinion carrier 23 on the side opposite to the 2-4 switching sleeve 50 with respect to the center differential 7. This differential sleeve 71 is inserted into the engaging portion 72 integrally formed with the sun gear 25 by an operation means (not shown).
It moves in the axial direction between an engagement position where it engages with the sun gear 25 and fixes the sun gear 25, and a non-engagement position where it does not engage with the engagement portion 72 and engages only with the first shaft 47. It's becoming like that. Therefore, when the differential sleeve 71 is set to the engagement position, the center differential 7 is fixed and immovable, and for example, when one wheel is idling on rough ground such as a muddy road, this idling wheel is This prevents the driving force from escaping through the wheels, allowing the appropriate driving force to be distributed to all wheels.

With the above configuration, the driving force output from the engine 1 is inputted to the input shaft 6 of the transmission 3 via the clutch means 5, and the gear is changed as appropriate, and the driving force is transferred from the drive gear 31 of the output shaft 8 to the center differential. It is output to the ring gear 22 of No. 7.

The driving force input to the ring gear 22 is distributed to a pinion carrier 23 that supports a planetary pinion 24 and a sun gear 25. The center differential 7 functions as a differential device and is capable of absorbing and alleviating the rotational speed difference between the pinion carrier 23 that drives the front differential 28 and the sun gear 25 that drives the rear differential 51.

Thus, the driving force distributed and transmitted to the sun gear 25 is transmitted to the short shaft 32 of the front differential case 29 via the drive gear 31 integrated with the sun gear 25, and is transmitted to a pair of bevel gears supported by the short shaft 32. 3
3, 34, and another pair of bevel gears 3 that mesh with these.
5 and 36, and the left and right front wheels 45 and 46 are thereby driven.

On the other hand, when the 2-4 switching sleeve 50 connects the first shaft 47 and the second shaft 49 at the engagement position, the driving force distributed and transmitted to the pinion carrier 23 is transmitted to the first shaft 47 and the second shaft 49. -4 The second shaft 49 is rotationally driven through the switching sleeve 50. As a result, the bevel gear 54 fixed to the second shaft 49 rotates, and by meshing with another bevel gear 57, the information is transmitted to the rear differential 51 via the propeller shaft 55. The rear wheels 52 and 53 are driven.

<Example 2> This example is an example in which the transmission is equipped with an auxiliary transmission.

In Fig. 3, the ring gear 2 of the center differential 7
2 meshes with a gear 83 formed integrally with a shaft 82 constituting a sub-transmission 81;
A low speed gear 84 and a high speed gear 85 are fitted and fixed in order from the 3 side, and a synchronization mechanism 86 is interposed between the two gears 84 and 85.

Gears 87 and 88 that mesh with the low speed gear 84 and high speed gear 85 are the output shaft 8 of the transmission 3.
is integrally formed.

As a result, the main transmission side is shifted in four stages, 1st gear, 2nd gear, 3rd gear, and 4th gear, while the auxiliary transmission side is shifted in 2 stages of high speed and low speed. will be shifted in 8 steps.

In addition, in the above embodiment, the front differential case 29
The transmission gear 30 provided on the outer periphery and the sun gear 25 of the center differential 7 mesh with each other, while one of the pair of bevel gears 54 for driving the rear wheels can be integrally fixed to the pinion carrier 23 of the center differential 7. The transmission gear 30 and the pinio carrier 23 of the center differential 7 are meshed, and one of the pair of bevel gears 54
may be integrally fixed to the sun gear 25 of the center differential 7.

Further, in the embodiment described above, the case where the engine 1 is disposed at the front of the vehicle body has been described, but it goes without saying that the present invention can also be applied to a case where the engine is disposed at the rear of the vehicle body.

(Effects of the Invention) As described above, the present invention can expand the degree of freedom in layout by offsetting the center differential and the front differential. In addition, by laying out the bevel gear coaxially with the center differential that serves as a reduction gear and transmitting power to the rear wheels, the power transmission path can be shortened and power transmission loss can be reduced. Furthermore, since the center differential is a planetary gear mechanism with a small width, it is possible to shorten the length of the shaft part and arrange the drive gear for transmitting power from the center differential to the front differential coaxially with the center differential. It is possible to satisfy the center differential shaft length limit when offset from the front differential. In addition, the front differential is offset from the center differential, so there are fewer restrictions in the width direction, so an inexpensive bevel gear mechanism can be used.
Cost reduction can be achieved.

[Brief explanation of the drawing]

The drawings illustrate embodiments of the invention.
The figure is a diagram schematically showing the drive system of Example 1 in skeleton form, Figure 2 is a diagram specifically showing the main parts of Example 1, and Figure 3 is the same as Figure 2 of Example 2. This is a diagram. 1... Engine, 2... Crankshaft, 3... Transmission, 6... Input shaft, 7... Center differential, 8... Output shaft, 22... Ring gear, 23
... Pinion carrier, 24 ... Planetary pinion, 25 ... Sun gear, 28 ... Front differential, 29 ... Front differential case, 30 ... Transmission gear, 31 ... Drive gear, 41, 42 ... Front wheel drive shaft, 50 ...2-4 switching sleeve, 54, 57
...Bevel gear, 58, 59...Rear wheel drive shaft, 71...
...Defrot sleeve, 81...Sub-transmission.

Claims (1)

[Scope of Claims] 1. An engine arranged so that the crankshaft extends in the left-right direction of the vehicle body, a transmission in which an input shaft and an output shaft having a drive gear are arranged in the left-right direction of the vehicle body, and the transmission. The center differential receives power from the output shaft of the center differential and distributes the power to the front wheels and the rear wheels, and the center differential receives power from the center differential and distributes the power to the left and right front wheels, and the center differential is equipped with a ring gear. , a sun gear, a planetary pinion, and a pinion carrier that supports the planetary pinion. It is considered a gear,
The sun gear and pinion carrier are two output gears that output power to the front wheels and the rear wheels, respectively, and the front differential consists of a bevel gear mechanism,
The shaft center is offset from the center differential, and has an input gear for inputting power from one of the output gears of the center differential, and further includes a pair of bevel gears for transmitting driving force to the rear wheel drive shaft. A four-wheel drive vehicle, characterized in that one of the bevel gears is arranged coaxially with a center differential and is configured to be integrally fixed to the other output gear of the center differential.