JPS6312818B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a four-wheel drive system for an automobile that transmits engine output to front wheels and rear wheels.

(Prior Art) In general, a four-wheel drive system for an automobile includes a transmission connected to an engine via a clutch device or a torque converter device, and the output of the transmission is distributed between front wheels and rear wheels. An inter-axle differential device, a front-wheel differential device that distributes the input from the inter-axle differential device to the left and right front wheels, and a rear-wheel differential device that also distributes the input from the inter-axle differential device to the left and right rear wheels. In addition, if necessary, a differential lock mechanism is provided to lock the inter-axle differential device, but in order to make these components compact, either the front wheel differential device or the rear wheel differential device is used. On the other hand, an inter-axle differential and its deflock mechanism are arranged coaxially.

As such a four-wheel drive device, for example, a four-wheel drive vehicle transmission device described in Japanese Patent Publication No. 47-20123 is known. As shown in FIG. 1, this is an input gear (crown gear) 3 that is driven by an output shaft 1 of a transmission (speed change gear box in the publication) via a pinion 2. An inter-axle differential device 4 and a rear wheel differential device 5 are arranged from the input gear 3 side, and a deflock mechanism (overrun one-way clutch device) 6 for the inter-axle differential device 4 and the vehicle body are arranged on the other side. Output gear (bevel gear) 8 to propeller shaft 7 extending in the front-rear direction
This is a configuration in which the following are arranged. The inter-axle differential device 4 is constituted by a planetary gear mechanism, and the power from the output shaft 1 of the lance transmission is input to the pinion carrier 4a, and the ring gear 4
The output from the sun gear 4c drives the rear wheel differential 5, and the output from the sun gear 4c drives the front wheel differential (not shown) via the output gear 8 and propeller shaft 7.

However, in the above configuration, since the input gear 3, inter-axle differential device 4, rear wheel differential device 5, deflock mechanism 6, and output gear 8 are arranged side by side on the same axis, the axial dimension is small. The pinion carrier 4 of the inter-axle differential 4 is significantly longer, especially when the power is
There is a drawback that the axial dimension becomes longer due to the relationship input to a. In other words, the ring gear 4b is on the outside of the pinion carrier 4a, and the sun gear 4 is on the inside.
c are located respectively, input to the carrier 4a must be made from the side, and therefore a certain axial dimension a is required between the differential 4 and the input gear 3. In addition, in the above configuration,
The arrangement position of the output gear 8 that drives the propeller shaft 7 is regulated by the inter-axle differential device 4, the rear wheel differential device 5, etc., and the output gear 8 or the propeller shaft 7 is
The disadvantage is that the free layout of the image is restricted.

Furthermore, according to JP-A No. 57-41216, similar to the above-mentioned JP-A No. 47-20123, an input gear, an inter-axle differential device, a differential lock mechanism, an inter-axle differential device (front wheel differential device), etc. ) and an output gear arranged coaxially, a power transmission device is shown in which the output gear that drives the propeller shaft is arranged close to the inter-axle differential on the outer periphery of the front wheel differential. For example, it can be expected that the axial dimension will be shorter than that shown in the above-mentioned Japanese Patent Publication No. 47-20123. However, even in this power transmission device, the arrangement position of the output gear is regulated by the inter-axle differential device and the front wheel differential device, so the layout of the propeller shaft is restricted, and the input gear Since the inter-axle differential device and the axle differential device are arranged side by side with their positions shifted in the axial direction, shortening of the axial dimension is hindered accordingly.

By the way, in order to free up the layout of the propeller shaft, it is conceivable to install the above output gear on a separate shaft from the inter-axle differential device, front wheel differential device, etc.; In addition to the input gear and the differential lock mechanism, it becomes necessary to provide a gear for driving the shaft provided with the output gear on the axis, resulting in an increase in the axial dimension.

Additionally, if an attempt is made to place the inter-axle differential close to the front wheel differential in order to suppress this increase in axial dimension, problems with the meshing of the pinions of the planetary gear mechanism constituting the inter-axle differential may occur. This problem is likely to occur, and the problem is how to configure it so that power can be transmitted between both differential gears while avoiding this problem. In other words, since the inter-axle differential device is disposed close to the front wheel differential device as in the power transmission device disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 57-41216, the sun gear, ring gear, and If all of the pinion carriers are supported by the differential case of the front wheel differential, their axes will be constrained by the differential case, and even a slight dimensional error of the pinion shaft in the pinion carrier will cause each pinion to Variation occurs in the meshing state of the pinion with the sun gear or ring gear, and the tooth contact of a particular pinion with the sun gear or ring gear becomes extremely strong, causing abnormal wear, breakage, gear noise, etc. Furthermore, in some cases, it becomes impossible to assemble the pinion or pinion carrier.

(Objective of the Invention) The present invention solves the above-mentioned conventional problems, and is aimed at solving the above problems in the conventional four-wheel drive vehicle, in which power is input from the drive gear of the transmission via the input gear. An inter-axle differential, a differential lock mechanism for the differential, a front-wheel differential driven by the output of one of the inter-axle differentials, and an output gear for the rear-wheel differential driven by the output of the other. By improving the arrangement of the above, the entire structure can be made compact, and the degree of freedom in the layout of the output gear, that is, the propeller shaft extending in the longitudinal direction of the vehicle body can be ensured. In addition, by supporting the pinion carrier in a floating manner with respect to the coaxially centered sun gear and ring gear in the inter-axle differential device, each pinion is always in an even and appropriate tooth contact state with respect to the sun gear and ring gear. This prevents abnormal wear and damage of the pinion, gear noise, etc. due to poor tooth contact, as well as the inability to assemble the pinion or pinion carrier. That is, an object of the present invention is to solve problems such as abnormal wear of gears in the above-mentioned inter-axle differential device, while achieving overall compactness and ensuring flexibility in the layout of the propeller shaft.

(Structure of the Invention) In order to achieve the above object, a four-wheel drive device according to the present invention is characterized by having the following structure.

That is, in a four-wheel drive vehicle in which an engine and a transmission connected to one side of the engine via a clutch device or a torque converter device are disposed horizontally at the front of the vehicle, a ring gear, a sun gear, and a transmission between these two gears are used. The transmission is a planetary gear mechanism composed of a pinion that meshes with the transmission, and a pinion carrier that supports the pinion, and an input gear that meshes with the drive gear in the transmission is provided on the outer periphery of the ring gear, so that the input gear can be connected from the drive gear to the input gear. an inter-axle differential device through which power is input to the ring gear, a front-wheel differential device whose differential case is driven by a pinion carrier of the inter-axle differential device to drive the front wheels, and a sun gear, which is also an inter-axle differential device. A drive gear coaxial with the sun gear,
A driven gear that meshes with the drive gear, an intermediate shaft provided with the driven gear, an output gear coaxial with the intermediate shaft, a rear wheel differential that drives the rear wheels via a propeller shaft, and an axle. The differential gear includes a differential lock mechanism that connects and separates the ring gear and pinion carrier in the differential gear. The inter-axle differential, the front wheel differential, the differential lock mechanism, and the drive gear are disposed coaxially, and the engagement points of the ring gear, pinion, and sun gear in the inter-axle differential are connected to the drive gear and the input gear. and a front wheel differential device is placed close to the engine side of the inter-axle differential device, and a deflock mechanism is placed close to the engine side of the front wheel differential device, respectively. In addition, while the drive gear is placed on the transmission side of the inter-axle differential,
The pinion carrier in the inter-axle differential and the differential case in the front wheel differential are configured to rotate together by spline fitting.

According to such a configuration, first, by arranging the input gear and the inter-axle differential on the same plane, the axial dimension is shorter than when these are arranged side by side in the axial direction. In addition, since the output gear that drives the rear wheel differential via the propeller shaft is provided on an intermediate shaft that is separate from the inter-axle differential, the front wheel differential, etc., the output gear or the propeller shaft is The degree of freedom in layout in the width direction of the vehicle body is ensured, and the propeller shaft can be placed, for example, in the center of the vehicle body. In addition, since the drive gear required by providing this output gear on a separate shaft is placed using the space created on the transmission side of the inter-axle differential, it is not necessary to provide the drive gear. The increase in the axial dimension due to this is suppressed, and in this way, the entire structure can be made compact while ensuring flexibility in the layout of the propeller shaft.
In a configuration in which an inter-axle differential device and a front wheel differential device whose differential case is driven by its pinion carrier are arranged in close proximity, the pinion carrier and the differential case are connected by spline fitting, so that the pinion carrier is floatingly supported with respect to the differential case, and the tooth contact between the pinion and the ring gear and sun gear in the inter-axle differential is improved while avoiding an increase in the axial dimension.

(Example) The present invention will be described below based on an example shown in the drawings.

FIG. 2 is a schematic diagram showing a transmission system of an automobile including a four-wheel drive device, and the engine 11 is installed horizontally so that the crankshaft 12 extends in the width direction of the vehicle body. Further, an input shaft 14 driven by the crankshaft 12 via a clutch 13, an output shaft 16 having a drive gear 15 at one end, and both shafts 1
A transmission 18 consisting of a transmission mechanism 17 provided between the engine 4 and the transmission 16 is also disposed laterally on one side of the engine 11 so that the input shaft 14 and the output shaft 16 extend in the width direction of the vehicle body. A drive gear 15 provided on the output shaft 16 of the transmission 18 meshes with a large-diameter input gear 21 integrally formed on the outer periphery of a ring gear 20 in the inter-axle differential 19.

As shown in an enlarged view in FIG. 3, this inter-axle differential device 19 includes the ring gear 20, a sun gear 22 coaxial therewith, and a plurality of pinions 23...23 meshing with the ring gear 20 and sun gear 22.
And these pinions 23...23 are connected to the pinion shaft 2.
4... Pinion carrier 25 supported via 24
It is constituted by a planetary gear mechanism consisting of pinions 23...23, a ring gear 20, and a sun gear 2.
The meshing points between the drive gear 15 and the input gear 21 are located on the same plane as the meshing points between the drive gear 15 and the input gear 21. Here, as shown in FIG. 4, the ring gear 2 in the inter-axle differential device 19
A plurality of pinions 23 between 0 and the sun gear 22...
23, a first pinion 23a that meshes with the ring gear 20, and the pinion 23a and the sun gear 2.
2 and a second pinion 23b that meshes with the second pinion 23b.

Further, on the coaxial side of the inter-axle differential device 19, on the right side (engine side), there is a differential case 26, and a radial pin 27 supported at both ends by the case 26.
A front wheel differential device 30 is arranged, which includes a pair of pinions 28, 28 rotatably fitted to the pin 27, and a pair of left and right bevel gears 29, 29 meshing with both pinions 28, 28. ing. The bevel gear 2 in the front wheel differential device 30
9, 29, a left front wheel drive shaft 3 extending in the left-right direction;
The left front wheel drive shaft 31 passes through the center of the inter-axle differential device 19 and reaches the left front wheel 33 as shown in FIG. The drive shaft 32 extends to the right front wheel 34.

Here, the ring gear 20 and sun gear 22 in the inter-axle differential 19 are different from the front wheel differential 30.
The inter-axle differential device 1 is relatively rotatably fitted and supported on the differential case 26 and is centered with respect to the differential case 26 .
The pinion carrier 25 at 9 is fitted to the differential case 26 via a spline A having play within an allowable range, and is configured to rotate integrally with the differential case 26 in a floating supported state.

Furthermore, the ring gear 20 in the inter-axle differential device 19 and the differential case 26 spline-fitted to the pinion carrier 25 are connected to the front wheel differential device 30.
a spline 35 of the same diameter that is extended to the right side (engine side) and formed adjacent to the outer periphery of the extended portion;
The ring gear 20 and pinion carrier 25 of the inter-axle differential device 19 are coupled by a sleeve 37 that can slide from a state fitted to one of them to a state fitted across both. Alternatively, a separate deflock mechanism 38 is constructed. In this way, the front wheel differential 30 is coaxially disposed on the engine side of the inter-axle differential 19, and the differential lock mechanism 38 of the inter-axle differential 19 is further disposed on the engine side.

On the other hand, an intermediate shaft 39 is arranged parallel to the axle center of the inter-axle differential device 19 and the front wheel differential device 30 at a constant distance. A driven gear 40 integrally formed with the intermediate shaft 39 is integrally formed with the sun gear 22 of the inter-axle differential 19, and a drive gear 41 is disposed on the left side (transmission side) of the differential 19. A second intermediate shaft 42 is disposed on an extension of the intermediate shaft 39, and a sleeve 45 is fitted into splines 43, 44 formed at adjacent ends of both intermediate shafts 39, 42. The intermediate shafts 39 and 42 are connected or separated by sliding the sleeve 45. Further, the second intermediate shaft 42 is provided with an output gear 46 formed of a crown gear, and the gear 46 has a bevel gear 48 integrated with a propeller shaft 47 extending in the longitudinal direction of the vehicle body.
are engaged. This propeller shaft 47
As shown in the figure, it reaches a rear wheel differential device 49, and drives left and right rear wheels 52, 53 via a left rear wheel drive shaft 50 and a right rear wheel drive shaft 51 extending left and right from the device 49.

According to the above configuration, the rotation of the crankshaft 12 in the engine 11 is input to the transmission 18 via the clutch 13, and the transmission 18 selects a reduction ratio, and then the output shaft 16 The signal is input from the upper drive gear 15 via the input gear 21 to the ring gear 20 in the inter-axle differential 19 . Then, the power input to the ring gear 20 is transmitted to the inter-axle differential device 1.
9 and output from the pinion carrier 25 and sun gear 22, respectively, and the output from the pinion carrier 25 is sent to the left and right front wheel drive shafts 31, 32 or the left and right front wheels 3 via the front wheel differential device 30.
3 and 34. In addition, the output from the sun gear 22 is transmitted to the driving gear 41, the driven gear 40, the intermediate shaft 3
The propulsion shaft 47 is driven through the output gear 46 and the output gear 46, and the left and right rear drive shafts 50, 51 and rear wheels 52, 53 are further driven through the rear wheel differential 49. In this case, the intermediate shaft 39 and the second
If the sleeve 45 fitted across the splines 43 and 44 of the intermediate shaft 42 is slid as shown by the chain line in FIG. 3 to separate the intermediate shafts 39 and 42, the output of the engine 11 will be directed only to the front wheels. It will be transmitted. In addition, in a state where both intermediate shafts 39 and 42 are coupled, that is, in a four-wheel drive state, the sleeve 37 in the differential lock mechanism 38 of the inter-axle differential 19 is slid as shown by the chain line, and the splines in the ring gear 20 and the differential case 26 are 35 and 36, the ring gear 20 and the pinion carrier 25 spline-fitted to the differential case 26 are coupled, thereby preventing the differential operation of the inter-axle differential device 19. . In the illustrated embodiment, since the pinion 23 in the inter-axle differential 19 is a double pinion, the output of the engine 11 is distributed approximately equally to the front wheel differential 30 and the rear wheel differential 49. It is divided and transmitted.

However, according to the above configuration, the input gear 21 for inputting power from the drive gear 15 to the ring gear 20 of the inter-axle differential 19 from the output of the transmission 18 is formed on the outer periphery of the ring gear 20. The engagement point between the gear 21 and the drive gear 15 is the ring gear 2 in the inter-axle differential 19.
0, pinion 23, and sun gear 22, the overall axial dimension is reduced compared to the case where these are arranged side by side and shifted in the axial direction. Furthermore, the front wheel differential 30 and the deflock mechanism 38 are arranged close to each other on the engine side of the inter-axle differential 19, and the intermediate shafts 39, 42 are installed in the empty space created on the transmission side of the inter-axle differential 19. or propeller shaft 47
Since the drive gear 40 is arranged to drive the
An increase in the axial dimension due to the provision of the drive gear 40 is suppressed.

Then, driven gear 41 is driven by this driving gear 40.
Since the output gear 46 that drives the propeller shaft 47 is provided on the axis of the intermediate shafts 39 and 42 that are driven through the intermediate shafts 39 and 42, the position of the output gear 46 in the vehicle width direction can be set freely. Therefore, the propeller shaft 47 is arranged in the engine 11, the transmission 18, and the differential gears 19, 3.
You can freely layout for 0 etc.
For example, it is possible to arrange it at the center in the width direction of the vehicle body.

Further, in the inter-axle differential device 19, the ring gear 20 and the sun gear 22 have both ends connected to the bearing 5.
The front wheel differential 30 is rotatably fitted and supported by the differential case 26 of the front wheel differential device 30 supported by the case 56 via the pinion carrier 25 which outputs power to the differential case 26. Since the ring gear 2 is supported in a floating manner via the spline A which has wobble, even if there is some error in the arrangement position of the plurality of pinion shafts 24...24 in the carrier 25, the ring gear 2
The carrier 25 will be automatically centered with respect to the zero and sun gear 22. As a result, while the inter-axle differential device 19 and the front wheel differential device 30 are disposed close to each other, the pinions 23...23 in the inter-axle differential device 19 are arranged with equal and appropriate teeth relative to the ring gear 20 and the sun gear 22. It becomes possible to mesh in a contact state.

(Effects of the Invention) As described above, according to the present invention, in a horizontally mounted engine type four-wheel drive system in which an inter-axle differential device, its differential lock mechanism, and a front wheel differential device are coaxially arranged, It is possible to arrange the above-mentioned devices and mechanisms in a compact manner while ensuring flexibility in the layout of the propeller shaft extending in the longitudinal direction of the vehicle body. This will create more space in the vehicle interior, especially under the front seats, improving the comfort of the vehicle, and will also facilitate the layout of various devices installed in the engine compartment and under the vehicle body. .

Particularly, according to the present invention, the plurality of pinions in the inter-axle differential device constituted by a planetary gear mechanism can always be in an even and appropriate tooth contact state with respect to the ring gear and the sun gear, without causing an increase in the widthwise dimension of the vehicle body. This makes it possible to prevent abnormal wear and damage of the pinion, gear noise, and inability to assemble the pinion or pinion carrier due to uneven tooth contact.
Furthermore, it is possible to reduce the manufacturing cost by lowering the machining accuracy.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing a conventional example, Fig. 2 is a schematic diagram of an embodiment of the present invention, Fig. 3 is an enlarged plan view of essential parts of the embodiment, and Fig. 4 is a cross section taken along the line of Fig. 3. It is a diagram. 11...Engine, 13...Clutch, 15...
...Drive gear, 18...Transmission,
19... Inter-axle differential device, 20... Ring gear,
21...Input gear, 22...Sun gear, 23...
Pinion, 25...Pinion carrier, 26...
Differential case, 30...Front wheel differential, 33, 34
...Front wheel, 38...Diff lock mechanism, 39, 42
... intermediate shaft, 46 ... output gear, 47 ... propeller shaft, 49 ... rear wheel differential, 52, 53 ... rear wheel, A ... spline.

Claims (1)

[Claims] 1. A planet consisting of a transmission connected to a horizontally placed engine via a clutch device or a torque converter device, a ring gear, a sun gear, a pinion meshing with both gears, and a pinion carrier supporting the pinion. an inter-axle differential device that is formed of a gear mechanism and has an input gear formed on the outer periphery of the ring gear that meshes with the drive gear in the transmission, and power is input from the drive gear to the ring gear via the input gear;
A front wheel differential device in which a differential case is driven by a pinion carrier in the inter-axle differential device to drive the front wheels, a drive gear coaxial with the sun gear by the sun gear in the inter-axle differential device, and a driven gear that meshes with the drive gear. , an intermediate shaft provided with the driven gear, an output gear coaxial with the intermediate shaft, and a rear wheel differential device that drives the rear wheels through the propeller shaft; and the ring gear in the inter-axle differential device. A differential lock mechanism is provided to connect and separate the pinion carrier, and the inter-axle differential, front wheel differential, differential lock mechanism, and drive gear are arranged coaxially, and the ring gear, pinion, and drive gear in the inter-axle differential are arranged coaxially. The meshing points of the sun gear are arranged on the same plane as the meshing points of the drive gear and the input gear, and a front wheel differential is disposed on the engine side of the inter-axle differential. A differential lock mechanism is disposed close to each other on the engine side of the transmission device, and a drive gear is disposed on the transmission side of the inter-axle differential device, and a pinion carrier of the inter-axle differential device and the front wheel differential are disposed close to each other. A four-wheel drive device for an automobile, characterized in that the device is configured to be spline-fitted to a differential case so as to rotate together.