JPH0538278Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention relates to an improvement of the transfer case of the transfer device in a so-called part-time four-wheel drive vehicle that can be switched between two-wheel drive mode and four-wheel drive mode. It is something.

(Prior Art) Conventionally, as a transfer device for a four-wheel drive vehicle, as disclosed in, for example, Japanese Patent Application Laid-Open No. 61-2972, a gear chamber housing a transmission gear device and a gear chamber in a transfer case are used. , an output distribution chamber (chain storage chamber) for storing a chain-type output distribution device is provided, and a separation plate (partition wall) extending to at least approximately the middle height of the gear chamber is provided at the boundary between the gear chamber and the output distribution chamber. By providing this, the movement of oil in the gear chamber and the movement of oil in the power distribution chamber are separated from each other by the separation plate, suppressing collision of both flowing oils and reducing stirring resistance in the power distribution chamber. Something like this has been proposed.

(Problem to be solved by the invention) By the way, in the transfer device of a part-time four-wheel drive vehicle that transmits the output of the transmission (engine) only to the rear wheels when driving two wheels, it is necessary to connect the drive to the transmission. A drive-side sprocket is supported on the input shaft and rotates while being connected to the input shaft during four-wheel drive; When the drive side sprocket is provided with a driven side sprocket connected via a chain, and the front wheel side output shaft (front wheel) is driven by the chain, in the two-wheel drive state, each sprocket on the input/output shaft Since there is no rotation or rotation of the chain, it is difficult for the lubricating oil accumulated in the lower part of the transfer case to be supplied to the input shaft side.

In order to solve this problem, an oil passage passing through the input shaft in the axial direction is provided, and an oil pump such as a trochoid pump is provided on the input shaft and communicates with the oil passage. By arranging the strainer in the lower part of the transfer case, the oil in the lower part of the case is supplied to the lubricating part on the input shaft side through the oil passage in the input shaft, thereby ensuring that the input shaft side is lubricated. is possible.

However, in this case, although there is no problem in two-wheel drive mode, in four-wheel drive mode, the chain rotates due to the rotation of the drive side sprocket, and the driven side sprocket located at the lower part of the transfer case rotates. As the oil rotates, the oil is splashed up and the oil level at the bottom of the case drops, causing air to be mixed with the oil and sucked into the oil strainer, resulting in an abnormal "chiyutsu, chutsu" noise due to air being sucked in. This causes problems such as oil pump seizure due to lack of oil.

In addition, due to the rotation of the chain, the stirring resistance due to the oil in the chain becomes large, and
Problems such as an increase in the calorific value of the oil due to the stirring action also occur.

The present invention was developed in view of these points, and its purpose is basically to increase the support strength of the bearing that supports the driven side sprocket, while making good use of the accompanying structure, and to achieve the above-mentioned structure. By dividing the lower part of the transfer case into two chambers using a member similar to the conventional separation plate, the oil level around the driven sprocket in the transfer case can be lowered during four-wheel drive, while The oil level in the oil strainer part of the oil pump is actively raised to reduce the stirring resistance of the chain and the amount of heat generated by the oil. The purpose is to prevent sticking and the generation of abnormal noise.

(Means for solving the problem) To achieve this purpose, the solution of the present invention is as follows:
A partition wall is provided on the inner lower wall of the transfer case where oil accumulates so as to separate the driven side sprocket and the oil strainer, and the partition wall makes the space of the oil strainer smaller in volume than the space of the sprocket, Even if the amount of oil accumulated in the lower part of the transfer case is small, the oil level in the oil strainer space is always increased, so that the oil level accumulated in both spaces is differentiated.

Specifically, the configuration of the present invention includes a drive-side sprocket that is supported on a drive shaft that is drive-connected to the transmission and rotates while being connected to the core drive shaft during four-wheel drive, and a drive-side sprocket that is located at the bottom of the transfer case. a driven side disposed within a driven shaft support section that supports the driven shaft below the drive shaft, supported on the driven shaft, and connected to the drive side sprocket via a chain in a chain connection section; sprocket and
an oil pump that is installed on the drive shaft and supplies lubricating oil for lubricating the lubricating part on the drive shaft side, and a lubricating oil to the oil pump is provided near the driven side sprocket in the driven shaft support section. The premise is a transfer case of a four-wheel drive vehicle transfer device, which has an oil strainer adjacent to it that sucks in oil.

and first and second bearings rotatably supporting the driven shafts near both sides of the driven sprocket on driven shaft support parts, respectively, and a driven shaft on the opposite side of the driven sprocket with respect to the first bearing. A third bearing rotatably supports the shaft on the driven shaft support part, and the axially opposing side wall parts of the driven shaft support part or the chain connection part continuous to the driven shaft support part are each provided with a third bearing rotatably supporting the shaft on the driven shaft support part. It is arranged so as to extend substantially straight up and down at positions corresponding to the first and second bearings.

Further, between the driven side sprocket and the strainer, the inside of the driven shaft support section is divided into a strainer chamber where the strainer is located and a sprocket chamber where the driven side sprocket is located and has a larger volume than the strainer chamber. A partition wall is provided, and the partition wall extends substantially upward from the bottom wall of the driven shaft support portion to the chain connection portion between the driving sprocket and the driven sprocket.

(Function) With this configuration, in the present invention, basically, the lubricating oil accumulated in the driven shaft support part at the bottom of the transfer case is sucked from the oil strainer by the oil pump that is driven by the drive shaft and operates. , after this oil is discharged from the pump,
Used to lubricate the lubricating part on the drive shaft side.

Between the driven sprocket on the drive shaft and the strainer, there is provided a sprocket that extends substantially upward from the bottom wall of the driven shaft support part at the bottom of the case to the chain connection between the drive sprocket and the driven sprocket. A partition wall is provided, and this partition wall divides the space within the driven shaft support section into a strainer chamber where the strainer is located and a sprocket chamber where the driven side sprocket is located. When the side sprocket, the driven side sprocket on the driven shaft, and the chain rotate or rotate, among the oil accumulated in the driven shaft support part, the oil on the sprocket chamber side is absorbed by the rotation of the driven side sprocket. The oil is splashed up, and part of it moves to the strainer chamber side due to the action of the partition wall, and as this process is repeated, the oil level in the driven shaft support section gradually becomes different between the sprocket chamber side and the strainer chamber side. , the oil level in the strainer chamber becomes higher than that in the sprocket chamber. Moreover, the volume of the strainer chamber in which the strainer is located is smaller than the sprocket chamber in which the driven side sprocket is located, so even if the amount of oil accumulated in the driven shaft support part itself is small, the strainer chamber has a volume corresponding to the smaller volume. The oil level in the chamber rises smoothly. These results
Ensure that the oil strainer is immersed in oil and
Air is not sucked into the strainer mixed with oil, thereby preventing seizure of the oil pump and generation of abnormal noise due to air suction.

Furthermore, since the oil level on the sprocket side is reduced, the agitation resistance to the oil when the chain rotates is reduced, and the amount of heat generated by the oil due to agitation is also suppressed.

Furthermore, first and second bearings rotatably support the driven shafts near both sides of the driven sprocket on the driven shaft support portions, respectively, and a driven shaft on the opposite side of the driven sprocket with respect to the first bearing. A third bearing is provided to rotatably support the shaft on the driven shaft support portion, and the driven shaft on the opposite side to the second bearing with respect to the driven side sprocket is provided with two bearings, the first and third bearings. The axially opposing side wall portions of the driven shaft support portion or the chain connection portion continuous to the driven shaft support portion extend substantially straight up and down at positions corresponding to the first and second bearings, respectively. Since the bearings extend in the direction, it is possible to increase the support strength of the first and third bearings, which bear the most load, on the driven shaft. In other words, by utilizing the structure in which the support strength of the first and third bearings is increased in this way, the driven shaft support portion is made smaller;
In addition, the volume of the strainer chamber can be made smaller than that of the sprocket chamber due to the partition wall inside the strainer chamber, and the oil level in the strainer chamber can be increased even when the amount of oil accumulated in the driven shaft support is small.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

In FIGS. 1 and 2, reference numeral 1 denotes a manual transmission drive-coupled to the output shaft of an engine mounted on a part-time four-wheel drive vehicle via a clutch mechanism (neither is shown). A transfer device 2 is disposed behind the transmission 1 to distribute engine power to front and rear wheels (none of which are shown) via front and rear axle shafts.

The transfer device 2 includes a transfer case 3 connected to the case 1a of the transmission 1,
The transfer case 3 is on the front side (left side in Figure 1)
It is divided into three parts in order from front case 4, center case 5, and rear case 6, and the center and rear cases 5, 6 each have main bodies 5a, 6a having approximately the same diameter as the front case 4, and main bodies 5a, 6a, respectively. Chain connecting portions 5b and 6 extend obliquely downward from 6a along a substantially vertical plane.
It is comprised of output shaft support parts 5c and 6c that are continuous via b. Inside the transfer case 3, there is an input shaft 7 as a drive shaft arranged on the same axis as the output shaft 1b of the transmission 1, and an input shaft 7 arranged parallel to the input shaft 7 on the side of the input shaft 7. a front wheel side output shaft 8 as a driven shaft; and a rear wheel side output shaft 9 arranged behind the input shaft 7 on the same axis as the input shaft 7.
The input shaft 7 is connected to each main body 5 of the front case 4, center case 5, and rear case 6.
a, 6a through bearings 10 to 12, and the rear output shaft 9 is connected to the rear case 6 through bearings 12 and 13 which also serve as support for the input shaft 7, and the front output shaft 8 is connected to It is rotatably supported by the output shaft support portions 5c and 6c of the central and rear cases 5 and 6 via bearings 14 to 16, respectively.

A speed reduction mechanism 17 is disposed at the front end of the input shaft 7, that is, at the end on the transmission 1 side, for switching the transmission ratio of power transmitted from the engine to the wheels between a low speed state and a high speed state. This speed reduction mechanism 17
The sun gear 20 is rotatably supported on the input shaft 7 via a radial bearing 18 and a thrust bearing 19, and is rotatably spline-coupled to the input shaft 7 at the rear of the sun gear 20, and meshes with the sun gear 20. multiple pinions 21,2
1,..., and a ring gear 23 meshing with each of the pinions 21, the ring gear 2
3, the teeth 23a on the outer peripheral surface of the front case 4
It is engaged with teeth 4a formed on the inner surface and is fixed to the transfer case 3 in a non-rotatable manner.
On the other hand, a sun gear spline tooth portion 20a is formed on the outer periphery of the front end of the sun gear 20, and a spline tooth portion 22a for a pinion carrier is formed on the inner periphery of the front end of the pinion carrier 22. Further, a cylindrical member 24 whose front end is rotatably splined to the output shaft 1b of the transmission 1 is disposed around the front end of the input shaft 7, and the outer peripheral surface of the rear end of the cylindrical member 24 is provided with the sun gear. Spline tooth portion 20a
A spline tooth portion 24a having the same diameter is formed on the spline tooth portion 24a, and a sleeve 25 having an inner circumferential spline tooth portion 25a capable of meshing with the sun gear spline tooth portion 20a at the rear end portion is slidably attached to the spline tooth portion 24a. The sleeve 2 is spline-coupled to rotate integrally.
On the outer peripheral surface of the rear end of 5 is a spline tooth portion 2 that can mesh with the spline tooth portion 22a for the pinion carrier.
5b is formed. A shift rod 26 is supported on the side of the transfer input shaft 7 so as to be slidable in the same direction as the input shaft 7, and a fork 27 that engages with the sleeve 25 and slides it. is fixed, and by sliding the shift rod 26, the sleeve 25 is slid back and forth on the cylindrical member 24, and the outer circumferential spline tooth portion 25b is connected to the pinion carrier spline tooth portion 22a or the inner circumferential spline tooth. Part 25
By selectively meshing the spline teeth 20a with the sun gear spline teeth 20a, the power transmission ratio is switched to a low speed state or a high speed state, and the sleeve 25 is positioned at the front end position (low speed position) as shown by the solid line in the figure. , when the outer circumferential spline tooth portion 25b is engaged with the pinion carrier tooth portion 22a, the output shaft 1b of the transmission 1 is directly connected to the transfer input shaft 7 to rotate integrally, and the rotation of the output shaft 1b is decelerated. By transmitting the power to the input shaft 7 as it is, the power transmission ratio is set to a high speed state, and the sleeve 25 is positioned at the rear end position (high speed position) as shown by the imaginary line, and the internal spline tooth portion 25
a is meshed with the sun gear teeth 20a, the transmission output shaft 1b is transmitted to the transfer input shaft 7 via the sun gear 20, each pinion 21, and the pinion carrier 22 to reduce its rotation. The power transmission ratio is configured to be in a low speed state.

On the other hand, a planetary gear type center differential 28 is disposed at the rear end of the transfer input shaft 7. A sun gear 29 of the center differential 28 is rotatably supported on the input shaft 7, and a pinion carrier 31 carrying each pinion 30 is rotatably spline-coupled to the input shaft 7 on the rear side of the sun gear 29.
The ring gear 32 is rotatably coupled to the rear wheel side output shaft 9.

Further, a drive side sprocket 33 is rotatably supported on the input shaft 7 on the front side of the center differential 28 via radial bearings 34, 34. On the other hand, a driven side sprocket 35 is rotatably coupled to the front output shaft 8 between the bearings 15 and 16, and a chain 36 is connected between the driven side sprocket 35 and the driving side sprocket 33. The chain 36 transmits the rotation of the input shaft 7 to the front output shaft 8.

That is, in this embodiment, the bearing 1
5 is a first bearing that rotatably supports the front wheel output shaft 8 near the front side of the driven side sprocket 35 on the output shaft support portion 5c;
Reference numeral 6 designates a second bearing that rotatably supports the front wheel output shaft 8 near the rear side of the driven side sprocket 35 on the output shaft support portion 6c. Further, the bearing 14 is a third bearing that rotatably supports the front wheel output shaft 8 on the side opposite to the driven side sprocket 35 with respect to the bearing 15 (first bearing) on the output shaft support portion 5c.

Of the front wall portions and rear wall portions facing each other in the axial direction in the output shaft support portions 5c, 6c or the chain connection portions 5b, 6b continuous to the output shaft support portions 5c, 6c, the front wall portion is on the front side. The rear wall portion extends substantially straight in the vertical direction at a position corresponding to the bearing 15 on the rear side, and at a position corresponding to the rear bearing 16, respectively.

Further, the sun gear 29 and ring gear 32 of the center differential 28 are each extended forward, and a clutch hub 37 having spline teeth 37a on the outer peripheral surface is rotatably coupled to the front end of the extension 29a of the sun gear 29. On the other hand, the extension part 32a of the ring gear 32 is supported on the outer periphery of the extension part 29a of the sun gear 29 through a radial bearing 38 so as to be relatively rotatable. A spline tooth portion 32b of a diameter is formed. Furthermore, the drive side sprocket 3
3 is extended rearward, and the spline tooth portion 3 on the outer periphery of the clutch hub 37 is provided on the outer periphery of this extended portion 33a.
A spline tooth portion 33b having the same diameter as 7a is formed. A sleeve 41 connected to the switching rod 39 via a fork 40 is attached to each spline tooth portion 37a, 32b, 33b of the clutch hub 37, the extension 32a of the ring gear 32 in the center differential 28, and the extension 33a of the drive side sprocket 33. Slidably splined,
The center differential 28 is switched between a free state and a locked state, or a two-wheel drive state and a four-wheel drive state, by the forward and backward sliding of the sleeve 41 caused by the sliding of the switching rod 39, and when the sleeve 41 is positioned at the front end position, the clutch hub 37 and the drive side sprocket 33 are rotationally connected to form a four-wheel drive state, and the ring gear 32 of the center differential 28 and the sun gear 29 are disconnected to put the center differential 28 in a free state. When positioned at the intermediate position between the front and back, the clutch hub 37 and the drive side sprocket 33 are rotatably connected to form a four-wheel drive state, and the ring gear 32 of the center differential 28 and the sun gear 29 are connected, in the same way as described above. The center differential 28 is then locked.
Furthermore, when the sleeve 41 is positioned at the rear end position as shown by the solid line in the figure, the center differential 28
The ring gear 32 and sun gear 29 are connected to lock the center differential 28, while the clutch hub 37 and drive sprocket 33 are disconnected to create a two-wheel drive condition.

Further, an oil pump 42 consisting of a trochoid pump is provided on the input shaft 7 between the bearing 11 and the drive side sprocket 33. As shown in FIG. 2, this oil pump 42 is connected to a housing 43 fixed to the central case 5.
and a rotor fitted in the housing 43 and rotationally driven by the input shaft 7. One end of the suction pipe 45 is fitted into the oil suction port 43a of the housing 43, and the suction pipe 45 extends obliquely downward along the lower surface of the inner wall of the central case 5, and its other end is connected to an oil strainer 46 disposed in front of and adjacent to the driven sprocket 35. On the other hand, the oil discharge port 43b of the housing 43 is communicated with each lubricating part on the input shaft 7 via an oil passage 7a formed through the input shaft 7, and the operation of the oil pump 42 causes the transfer case 3 to be Each output shaft support part 5c, 6c of the center side and rear side cases 5, 6 which constitute
The lubricating oil accumulated therein is supplied to the lubricating portion on the input shaft 7.

Further, in the output shaft support parts 5c, 6c at the lower part of the transfer case 3, between the driven side sprocket 35 and the strainer 46, there is a connection between the drive side sprocket 33 and the drive side sprocket 33 from the bottom wall of the output shaft support parts 5c, 6c. A partition wall 47 is provided that extends substantially upward to the chain connecting portions 5b and 6b between the driven sprocket 35 and the inner lower part of the transfer case 3 (each of the central and rear cases 5). , 6) is divided into a front chamber 48 which is a strainer chamber in which the strainer 16 is disposed, and a rear chamber 49 which is a sprocket chamber in which the driven side sprocket 35 is located.

Therefore, in the above embodiment, while the vehicle is running, the input shaft 7 connected to the engine via the transmission 1 rotates, and the oil pump 42 is operated by the drive of the input shaft 7. oil pump 4
2, the lubricating oil accumulated in the inner lower part of the output shaft support portions 5c and 6c of the central and rear cases 5 and 6 of the transfer case 3 is sucked from the oil strainer 46, and this oil is transferred to the pump. 42 and supplied to each lubricating portion on the input shaft 7 side.

During two-wheel drive, only the rear wheels are driven and rotated, and the front wheels do not rotate. Therefore, the drive side sprocket 33 connected to the front wheels, the driven side sprocket 35 on the front wheel side output shaft 8, and the chain 36 do not rotate or rotate. I don't go.

On the other hand, during four-wheel drive in which the front and rear wheels rotate, both sprockets 33, 35 and chain 36 rotate or rotate.

In that case, between the driven side sprocket 35 and the strainer 46, output shaft support parts 5c and 6 are provided.
Chain connecting portion 5 between the driving side sprocket 33 and the driven side sprocket 35 from the bottom wall of c.
Since a partition wall 47 is provided that extends substantially upward to 6b and 6b, the partitioning action of this partition wall 47 allows the oil accumulated in the output shaft support portions 5c and 6c at the lower part of the transfer case 3 to be removed. Among them, the rear chamber 4 in which the driven side sprocket 35 is arranged.
The oil in the sprocket chamber 9 (sprocket chamber) is splashed up by the rotation of the sprocket 35, and a part of it moves over the partition wall 47 to the front chamber 48 (strainer chamber) on the oil strainer 46 side. As this oil movement is repeated, a difference in oil level between the front and rear chambers 48 and 49 gradually arises, and the oil level in the front chamber 48 becomes higher than that in the rear chamber 49. Therefore, the oil strainer 46 disposed in the front chamber 48 is reliably immersed in the oil in the front chamber 48, and air is not sucked into the strainer 46 mixed with the oil, thereby preventing oil shortage. It is possible to prevent the oil pump 42 from seizing or from generating abnormal noises such as "thud" due to air suction.

Furthermore, since the oil level in the rear chamber 49 on the sprocket 35 side is reduced, it is possible to reduce the stirring resistance caused by the oil as the chain 36 rotates, and also to suppress the amount of heat generated by the oil due to the stirring. .

Moreover, the partition wall 47 provided at the lower part of the transfer case 3 connects the driving side sprocket 33 and the driven side sprocket 35 from the bottom wall of the case.
Since the front chamber extends substantially upward to the portion between the chain connecting portions 5b and 6b, which has a relatively small cross-sectional area space between the 4
A large amount of oil in the oil strainer 8 does not overflow over the partition wall 47, so that the oil can be reliably sucked into the oil strainer 46.

Further, an oil strainer 46 for the oil pump 42 is attached to the output shaft support portion 5 of the transfer case 3 for arranging the driven side sprocket 35.
Since it is located adjacent to the driven side sprocket 35 in the lower part of the strainer 46, the space for the strainer 46 can be reduced, and there is no need to provide a separate chamber for oil suction, so the transfer case 3 can be kept compact.

Furthermore, the front wheel side output shaft 8 has bearings 15, 1 on both front and rear sides of the driven side sprocket 35.
6 and a bearing 14 at the front end, and supported by two bearings 14 and 15 on the front side of the driven side sprocket 35.
Further, the front and rear wall portions of the output shaft support portions 5c, 6c or the chain connection portions 5b, 6b which are continuous thereto, which face each other in the axial direction, are provided with bearings 15 on both sides of the driven side sprocket 35, respectively.
Since it extends substantially straight in the vertical direction at a position corresponding to 16, it is possible to increase the support strength of the bearings 14 and 15, which bear the most load, on the front wheel side output shaft 8. In other words, by utilizing the structure in which the support strength of both the bearings 14 and 15 is increased, the size of the output shaft support parts 5c and 6c is reduced, and the partition wall 47 inside the rear chamber 49 is The volume can be made smaller than that of the front chamber 48, and the oil level in the front chamber 48 can be stably raised even with a small amount of oil accumulated in the output shaft support parts 5c, 6c. It is possible to reliably prevent air inhalation, etc.

(Effects of the invention) As explained above, according to the invention, during four-wheel drive, the transmission is transmitted from the drive shaft connected to the transmission to the driven shaft disposed below it through the chain and sprocket. In a transfer device for a part-time four-wheel drive vehicle, the driven side sprocket on the driven shaft is supported by bearings near both sides and one side thereof, and the driven shaft support part or the lower part of the transfer case is supported by bearings. The opposing side walls of the continuous chain connection section are arranged so as to extend substantially straight up and down, corresponding to the bearing positions near both sides of the driven side sprocket. An oil pump for lubrication on the drive shaft side is provided to draw oil accumulated at the lowest part through a strainer, and an oil pump is provided between the strainer and the driven side sprocket located adjacent to it, from the bottom wall of the case to the chain connection section. By providing a partition wall that extends almost upward and partitions the inside of the driven shaft support section into a strainer chamber and a sprocket chamber that has a larger volume, it increases the support strength of the bearing that carries the most load on the driven shaft. By using this structure, the driven shaft support part can be made smaller, and the volume of the strainer chamber can be made smaller than that of the sprocket chamber by the partition wall inside the part, and during four-wheel drive, the driven shaft support part at the bottom of the transfer case can be made smaller. Even if a small amount of oil accumulates inside the shaft support, the oil level in the strainer chamber can be stably raised and kept higher than the sprocket chamber, preventing the oil pump from seizing or causing abnormal noise due to air being sucked in from the strainer. This can be reliably prevented, and it is also possible to reliably suppress an increase in stirring resistance and heat generation amount of oil due to rotation of the chain.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal sectional view of the transfer device, and FIG. 2 is a cross-sectional view of the transfer device.
FIG. 2...Transfer device, 3...Transfer case, 5b, 6b...Chain connection part, 5c,
6c...Output shaft support part, 7...Input shaft, 8...Front wheel side output shaft, 33...Drive side sprocket, 14
~16... Bearing, 35... Driven side sprocket, 36... Chain, 42... Oil pump, 46... Oil strainer, 47... Partition wall, 48... Front chamber, 49... Rear chamber.

Claims (1)

[Claims for Utility Model Registration] Supported on a drive shaft drivingly connected to a transmission,
a drive-side sprocket that is connected to and rotates with the drive shaft during four-wheel drive; and a drive-side sprocket that is located in a lower portion of the transfer case and that supports the driven shaft below the drive shaft; A driven side sprocket supported on the shaft and connected to the drive side sprocket via a chain in a chain connection part, and a lubricating oil provided on the drive shaft to lubricate the lubricating part on the drive shaft side. A transfer case of a transfer device for a four-wheel drive vehicle, comprising: an oil pump for sucking lubricating oil to the oil pump; first and second bearings that rotatably support driven shafts near both sides of the driven sprocket, respectively, on driven shaft support parts; A third bearing rotatably supports the driven shaft on the driven shaft support part, and a side wall part facing in the axial direction of the driven shaft support part or a chain connection part continuous to the driven shaft support part. extend substantially straight up and down at positions corresponding to the first and second bearings, respectively, and between the driven side sprocket and the strainer, a strainer chamber in which the strainer is located and a strainer chamber in which the strainer is located are provided between the driven side sprocket and the strainer. A partition wall is provided to separate the drive side sprocket from the drive side sprocket and the sprocket chamber having a larger volume than the strainer chamber. A transfer case for a four-wheel drive vehicle, characterized in that the transfer case extends substantially upward to the chain connection portion between the two.