JP2000071792A - Impact absorbing propeller shaft structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently absorb and reduce impact in collisions by adding, at the end of the propeller shaft, a cylindrical connecting portion which permits sliding movement on one end of the propeller shaft in a collision. SOLUTION: On one end closer to a transfer 8 side of a front propeller shaft 18, a cylindrical connecting portion 82 is provided to permit sliding movement of one end of the front propeller shaft 18 in a collision. The cylindrical connecting portion 82 comprises a double offset joint(DOJ) portion 84 mounted to a stub shaft 18a, and a cylindrical portion 86 which connects the DOJ portion 84 with a transfer output shaft 72. In a collision, an outer wheel 84-1, an inner wheel 84-2, and a ball portion 84-3 are disengaged at the DOJ portion 84, and the stub shaft 18a and the inner wheel 84-2 of the DOJ portion 84 slide to the side of the transfer output shaft 72. This efficiently absorbs and reduces impact in collisions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock-absorbing propeller shaft structure, and more particularly to a cylindrical connecting portion for allowing one end of a propeller shaft to slide during a collision. The present invention relates to a shock absorbing propeller shaft structure capable of absorbing and relaxing and improving safety.

[0002]

2. Description of the Related Art Automobiles are equipped with a gear transmission or an automatic transmission as a transmission as a power transmission mechanism for converting a driving force from a mounted internal combustion engine into a desired state in accordance with running conditions and taking out the power.

The transmission is composed of a plurality of transmission gear trains such as an input gear train, a first gear train to a fifth gear train, a reverse gear train, and the like.
The driving force of the internal combustion engine input via the input shaft is shifted to a predetermined state. Then, the wheels are driven via the output shaft by the shifted driving force.

There is also a four-wheel drive type transmission in which a transfer is mounted and a driving force is transmitted to front and rear wheels by the transfer to drive four wheels.

The four-wheel drive system includes a part-time system and a full-time system. In the case of the part-time system, for example, a front engine / rear drive (FR) system is adopted, The driving force is also transmitted to the front wheels.

An example of the shock absorbing propeller shaft structure is disclosed in Japanese Patent Application Laid-Open No. Hei 7-117502. The layout structure of the vehicle disclosed in this publication is:
In a vehicle in which a driving force is transmitted from a power unit side transfer behind the front differential gear via a propeller shaft having a two-way split structure to the front differential gear, the vehicle extends in the vehicle width direction, and a front end of the front differential gear A first cross member that supports the first cross member and a second cross member that extends in the vehicle width direction and that detachably supports the rear end of the front differential gear when a load equal to or more than a predetermined value is applied, The front differential gear front end support point of the first cross member is set at a position lower than the front differential gear rear end support point of the second cross member, so that the Shogi family energy at the time of a vehicle collision is effectively reduced. It allows for absorption.

[0007] Another example is disclosed in Japanese Patent Application Laid-Open No. 9-109708. A propeller shaft structure of a vehicle disclosed in this publication includes a propeller shaft arranged to extend in the front-rear direction of the vehicle and transmitting a driving force of a power unit to a wheel side, a bearing body fitted to the propeller shaft, A holding portion extending around the bearing body in the circumferential direction and holding the bearing body via an elastic member, and a flange portion provided at both ends of the holding portion and provided with a screw hole for being supported by the vehicle body are provided. A propeller shaft structure for a vehicle, comprising: a support member having a support member; and a contact portion provided on the propeller shaft so as to be opposed to the support member with a space therebetween. A narrow part or notch is formed between the hole and the end of the flange part in the width direction of the vehicle to serve as a fracture starting point, ensuring support rigidity during normal running and receiving a collision load. And is both a departure from rapid vehicle propeller shaft when.

[0008] Furthermore, there is one disclosed in JP-A-9-123774. In the vehicle propeller shaft structure disclosed in this publication, in a vehicle in which a propeller shaft is divided into front and rear shafts, an inner spline portion and an outer spline portion which are press-fitted to each other are formed on the front and rear shafts. An inner circumferential groove is formed on the inner circumference of one shaft having the spline portion formed therein, and a snap engaged with the inner circumferential groove and locked in the front-rear direction is formed on the outer circumference of the other shaft having the outer spline portion formed therein. When the ring is attached and the axial load more than the set value is applied to the front and rear shafts, the snap ring comes off the inner peripheral groove and the front and rear shafts can slide in the axial direction, without reducing the shock absorption performance In addition, wear and vibration due to backlash are prevented, and the propeller shaft is prevented from falling off.

[0009]

By the way, in a conventional vehicle, for example, a truck or van type, the bonnet portion is short in the longitudinal direction of the vehicle.・ I cannot relax.

Here, the structure of the conventional propeller shaft will be described. As shown in FIG. 9, the transmission 206 supports an input shaft 234, a counter shaft 236, and an output shaft 238 in a transmission case 232. .

The input shaft 234 and the output shaft 238
Are connected so as to have the same rotation center, and the input shaft 23 is provided.
4 and the counter shaft 236 are provided in parallel with the output shaft 238. A plurality of transmission gear trains 240 are provided between the respective shafts 234 to 238. This plurality of transmission gear trains 2
Reference numeral 40 includes, for example, an input gear train (not shown), a primary reduction gear train 242 to a fifth gear train 250, and a reverse gear train 252.

A third-speed / fourth-speed switching mechanism 254 is provided between the primary reduction gear train 242 and the third-speed gear train 244, and a first-speed / fourth-speed gear train 246 is provided between the second-speed gear train 246 and the first-speed gear train 248. A second speed switching mechanism 256 is provided, and a fifth speed / reverse switching mechanism 258 is provided between the fifth speed gear train 250 and the reverse gear train 252.
Is provided.

Further, a transmission case 232 of the transmission 206 includes a transmission upper case 260 surrounding the upper side of the input shaft 234.
A transmission lower case 262 surrounding the lower side of the input shaft 234; a transmission rear case 264 surrounding the output side of the input shaft 234 and the fifth speed / reverse switching mechanism 258; And a switching case 268 surrounding the mechanism 266.

A transfer drive sprocket 270 is provided on the output shaft 238, and FIGS.
As shown in the figure, a transfer driven sprocket 274 is provided on a transfer output shaft 272 of the transfer 208, and a transfer drive sprocket 270 and a transfer driven sprocket 274 are provided.
And the transfer chain 276 is wound around and provided.

Reference numerals 278 and 280 are bearings for supporting both ends of the transfer driven sprocket 274.

At this time, as shown in FIG. 10, the transfer output shaft 272 is formed in a cylindrical shape, and the transfer output shaft 272 is provided so as to be connected to one end side of the front propeller shaft 218, and the transfer driven sprocket 274 is provided.
The driven sprocket shaft 328 is formed integrally with the transfer driven sprocket 274, and the bearings 278 and 280 located on both sides of the transfer driven sprocket 274 have the bearing 278 on the transfer output shaft 272 side.
A spline fitting portion 300 between the transfer output shaft 272 and the driven sprocket shaft 328 of the transfer driven sprocket 274 is provided closer to the transfer output shaft 272.

However, at the time of a collision, it is necessary to crush the entire vehicle. However, the straight pipe type propeller shaft A using the cross joint type as described above (see FIG. There is a disadvantage that it is not possible to expect absorption or mitigation.

As a measure for crushing the propeller shaft, as shown in FIG. 11B, a pipe member is squeezed to form a propeller shaft B, or as shown in FIG. There is a type in which a propeller shaft C is formed by providing a slide spline and fixing two cylindrical members with pins that are sheared at the time of a collision. However, if the mounting state of the propeller shaft is inclined, the propeller shaft may be stretched. Therefore, improvement was desired.

[0019]

SUMMARY OF THE INVENTION In order to eliminate the above-mentioned disadvantages, the present invention provides a propeller shaft having one end connected to a transmission connected to an internal combustion engine and the other end connected to a differential gear mechanism. In the provided internal combustion engine, a cylindrical connecting portion is provided at one end side portion of the propeller shaft to allow sliding movement of one end side of the propeller shaft at the time of collision.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION
At the time of a collision, the sliding movement of the one end side of the propeller shaft is allowed by the cylindrical connecting portion provided at one end side portion of the propeller shaft, and the impact at the time of the collision is efficiently absorbed and mitigated to improve safety.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

FIGS. 1 to 5 show a first embodiment of the present invention. In FIG. 2, reference numeral 2 denotes a four-wheel drive vehicle,
Reference numeral 4 denotes, for example, a vertical internal combustion engine, and reference numeral 6 denotes a transmission.

As shown in FIG. 2, the vehicle 2 has a vertically mounted internal combustion engine 4 on the front side, a transmission 6 mounted on the internal combustion engine 4, and a transfer 8 mounted on the transmission 6.

At this time, the internal combustion engine 4 is supported by the frame 12 via the engine mount member 10, and the transfer 8 is supported by the frame 12 via the mount member 14.

A front propeller shaft 18 is connected to the transmission 6, more precisely, one end of the transfer 8, and the other end is connected to a front differential gear mechanism 16. One end of the front propeller shaft 18 is connected to the transfer 8. At the same time, a rear propeller shaft 22 having the other end connected to the rear differential gear mechanism 20 is provided.

The front differential gear mechanism 16 is disposed in the middle of a front wheel axle 26 provided with front wheels 24 at both ends, and the rear differential gear mechanism 20 is provided with a rear wheel axle provided with rear wheels 28 at both ends. It is arranged in the middle of 30.

Further, the transmission 6 shown in FIG.
As shown in the figure, an input shaft 34, a counter shaft 36, and an output shaft 38 are supported in the transmission case 32.

The input shaft 34 and the output shaft 38 are connected so as to have the same center of rotation, and a counter shaft 36 is provided in parallel with the input shaft 34 and the output shaft 38.
A plurality of transmission gear trains 40 are provided between the respective shafts 34 to 38. The plurality of transmission gear trains 40 include, for example, an input gear train (not shown) and a primary reduction gear train 42 to a fifth gear train 5.
0 and a reverse gear train 52.

A primary reduction gear train 42 and a third speed gear train 4
A third-speed / fourth-speed switching mechanism 54 is provided between the first-speed and second-speed gear trains 46 and a first-speed / second-speed switching mechanism 56
And a fifth speed / reverse switching mechanism 58 is provided between the fifth speed gear train 50 and the reverse gear train 52.

The transmission case 32 of the transmission 6 includes a transmission upper case 60 surrounding the upper side of the input shaft 34, a transmission lower case 62 surrounding the lower side of the input shaft 34, and an output of the input shaft 34. A transmission rear case 64 surrounding the side and the fifth speed / reverse switching mechanism 58 and a switching case 68 surrounding a two-wheel drive / four-wheel drive switching mechanism 66 are provided.

A transfer drive sprocket 70 is provided on the output shaft 38, and a transfer driven sprocket 74 is mounted on a transfer output shaft 72 of the transfer 8 as shown in FIGS.
And a transfer chain 76 is wound around the transfer drive sprocket 70 and the transfer driven sprocket 74.

Reference numerals 78 and 80 denote bearings for supporting both ends of the transfer driven sprocket 74.

Then, the front propeller shaft 1
8 has a cylindrical connecting portion 82 that allows the one side of the front propeller shaft 18 to slide during a collision.
Is provided.

More specifically, as shown in FIG. 1, a cylindrical connecting portion 82 is provided at one end of the front propeller shaft 18, that is, at the transfer 8 side.

At this time, the cylindrical connecting portion 82 is
The front propeller shaft 18 includes a DOJ (double offset joint) 84 mounted on a stub shaft 18 a, which is one end of the front propeller shaft 18, and a cylindrical portion 86 connecting the DOJ 84 to the transfer output shaft 72.

The DOJ portion 84 comprises an outer ring 84-1, an inner ring 84-2, and a ball portion 84-3 disposed between the outer ring 84-1 and the inner ring 84-2, and is provided on the stub shaft 18a side. Is attached to the stub shaft 18a by a fixture 90 via a seal member 88.

The cylindrical portion 86 has a first mounting portion 86-1 mounted on the DOJ portion 84 by a bolt 94 via a grease cover 92 which is a rubber vulcanized product with a sheet metal.
A second mounting portion 86-2 mounted on the transfer output shaft 72 by a bolt 96; and a cylindrical connecting portion 86-3 connecting the first and second mounting portions 86-1 and 86-2. are doing.

The transfer output shaft 7
Flange 98 on front propeller shaft 18 side
Is formed, and the second portion of the cylindrical portion 86 is
The mounting portion 86-2 is mounted with the bolt 96, and the spline fitting portion 100 with the transfer driven sprocket 74, which is a sprocket formed on the outer periphery of the transfer output shaft 72, is supported at both ends of the transfer driven sprocket 74. It is provided between the bearings 78 and 80 and on the inner diameter side of the transfer driven sprocket 74.

Further, after the transfer driven sprocket 74 and the transfer output shaft 72 are spline-fitted, a tightening nut for tightening and fixing the transfer output shaft 72 on the side away from the front propeller shaft 18 which is the vehicle rear side. 10
2 is provided.

Then, one end of the front propeller shaft 18, that is, the stub shaft 18a and the DO
From the initial mounting position of the J portion 84 with the inner race 84-2, the flange portion 98 of the transfer output shaft 72
The slidable length, which is the distance to the concave portion 104 formed inside, is secured in the cylindrical connecting portion 82.

Next, the operation will be described.

At the time of a collision in which an external force acts from the front of the vehicle 2, the outer wheel 84-1 and the inner wheel 84
-2 and the ball portion 84-3 are disengaged, and one end of the front propeller shaft 18, that is, the stub shaft 18a and the inner ring 84-2 of the DOJ portion 84 slide toward the transfer output shaft 72. .

At this time, the stub shaft 18a and the DOJ
The inner ring 84-2 of the portion 84 includes a DOJ portion 84 and a cylindrical portion 86.
Grease cover 92 interposed between the first mounting portions 86-1
Through the first mounting portion 86-1 and the cylindrical connecting portion 86-
After 3, the slider slides inside the cylindrical portion 86 toward the second mounting portion 86-2.

Then, the stub shaft 18a and the DO
The slidable length of the J portion 84 with the inner ring 84-2 is
The transfer output shaft 72 reaches the concave portion 104 formed inside the flange portion 98 of the transfer output shaft 72.

Thus, the cylindrical connecting portion 82 provided at one end of the front propeller shaft 18 allows
Sliding movement of one end side of the front propeller shaft 18 can be allowed at the time of a collision, and the impact at the time of a collision can be efficiently absorbed and mitigated to improve safety.

Further, by providing the spline fitting portion 100 between the transfer output shaft 72 and the transfer driven sprocket 74 between the bearings 78 and 80 and on the inner diameter side of the transfer driven sprocket 74, the axial direction of the transfer output shaft 72 is improved. Can be shortened and compact, the bush for aligning the rotating center can be eliminated, the number of parts can be reduced, the cost can be reduced, and it is economically advantageous.

Further, after the transfer driven sprocket 74 and the transfer output shaft 72 are spline-fitted, the tightening nut 1 is separated from the front propeller shaft 18 which is the vehicle rear side.
02, the transfer output shaft 72 is tightened and fixed, so that the tightening nut 102 is located on the opposite side to the front propeller shaft 18, and can be made compact in the axial direction, and the DOJ portion 84 which is a heavy The slideable length can be ensured, and the rotational balance can be improved, which can contribute to sound and vibration countermeasures.

FIG. 6 shows a second embodiment of the present invention. In the second embodiment, portions that perform the same functions as those in the first embodiment will be described with the same reference numerals.

The feature of the second embodiment is that D
Instead of the OJ (double offset joint) part 84, the same sliding constant velocity joint TJ
That is, the joint 112 is used.

That is, the configuration of the first embodiment is used as it is, and only the DOJ section 84 is replaced with the TJ section 112.

That is, as is clear from FIG. 6, the configuration of the cylindrical portion 86 of the cylindrical connecting portion 82 except for the DOJ portion 84 in the first embodiment and the transfer output shaft 72
, The configuration of the spline fitting portion 100, and the configuration of the fastening nut 102 can be the same.

In this case, the sliding movement of the one end of the front propeller shaft 18 at the time of collision is permitted by the cylindrical connecting portion 82 provided at one end of the front propeller shaft 18 in the same manner as in the first embodiment. Thus, it is possible to efficiently absorb and mitigate the impact at the time of collision, thereby improving safety.

Further, since the spline fitting portion 100 for the transfer output shaft 72 and the transfer driven sprocket 74 is provided between the bearings 78 and 80 and on the inner diameter side of the transfer driven sprocket 74, the first embodiment is different from the first embodiment. Similarly, the length of the transfer output shaft 72 in the axial direction can be reduced, the size can be reduced, the bush for aligning the rotating center can be eliminated, the number of parts can be reduced, the cost can be reduced, and the cost can be reduced. It is advantageous.

Further, after the transfer driven sprocket 74 and the transfer output shaft 72 are spline-fitted, the fastening nut 1 is separated from the front propeller shaft 18 which is the rear side of the vehicle.
02, the transfer output shaft 72 is tightened and fixed, so that the tightening nut 102 is connected to the front propeller shaft 18 in the same manner as in the first embodiment.
, Which can be compact in the axial direction, can secure the slidable length of the heavy TJ portion 112, and can also improve the rotational balance, and can also be used as a sound and vibration countermeasure. Can contribute.

FIG. 7 shows a third embodiment of the present invention.

The feature of the third embodiment is that the transfer output shaft 12 having the conventional structure is used.
2 in that a cylindrical connecting portion 124 is used.

That is, as shown in FIG. 7, the transfer output shaft 122 is formed in a cylindrical shape, and the driven sprocket shaft 128 is formed integrally with the transfer driven sprocket 126, and the bearings 78 located on both sides of the transfer driven sprocket 126 are formed. , 80, the transfer output shaft 122 and the driven sprocket shaft 1 of the transfer driven sprocket 126 are located at a position closer to the transfer output shaft 122 than the bearing 78 on the transfer output shaft 122 side.
28 is provided.

The cylindrical connecting portion 124 is connected to a DOJ portion 84, and the cylindrical portion 1 formed integrally to connect the DOJ portion 84 to the transfer output shaft 72.
32.

Further, the transfer output shaft 122 and the transfer driven sprocket 126
After the driven sprocket shaft 128 is spline-fitted, the transfer output shaft 12
The tightening nut 134 for tightening and fixing 2 is located in the internal space 136 of the cylindrical portion 132 of the cylindrical connecting portion 124.

Then, by the cylindrical connecting portion 124 provided at one end side of the front propeller shaft 18,
As in the first and second embodiments, the slide movement of one end of the front propeller shaft 18 can be permitted at the time of a collision, and the impact at the time of a collision can be efficiently absorbed and mitigated, thereby improving safety. Can be improved.

Further, since the transfer output shaft 122 having the conventional structure can be used, it is possible to sufficiently cope with the vertical without needing to make a design change and newly providing a transfer output shaft. It is easy to manufacture, can keep costs low, and is economically advantageous.

The present invention is not limited to the above-described first to third embodiments, and various modifications can be made.

For example, in the first embodiment of the present invention, a concave portion 104 is formed inside the flange portion 98 of the transfer output shaft 72, and the concave portion 104 allows the stub shaft 18a and the inner ring 84 of the DOJ portion 84 to be formed.
-2, the stub shaft 18a and the inner race 84- of the DOJ portion 84 are allowed to slide.
When the collision force is large enough to release the engagement state with the stub shaft 2, the stub shaft 18a may be allowed to slide only.

That is, as shown in FIG. 8, when the transfer output shaft 142 collides with the front propeller shaft 18 side, the front propeller shaft 18
Stub shaft 18a and DOJ portion 84
Recess 1 that allows sliding movement of inner ring 84-2
44 is provided inside the flange portion 146 of the transfer output shaft 142, and a second concave portion 148 is provided (SG1) that allows only the end of the front propeller shaft 18, that is, the stub shaft 18a to slide.

Then, at the time of collision, the stub shaft 18
a and the inner ring 84-2 of the DOJ part 84 are covered with the grease cover 92.
Through the first mounting portion 86-1 and the cylindrical connecting portion 86-
3 and slides in the cylindrical portion 86 of the cylindrical connecting portion 82 toward the second mounting portion 86-2, and the inner ring 8 of the DOJ portion 84
4-2 abuts against the first recess 104 formed inside the flange portion 146 of the transfer output shaft 142.

At this time, if the collision force is large enough to release the engagement between the stub shaft 18a and the inner ring 84-2 of the DOJ portion 84, the stub shaft 18a
The slide movement is performed until only a contacts the second concave portion 148.

Thus, the cylindrical connecting portion 82 provided at one end of the front propeller shaft 18 allows
Similar to the first to third embodiments, one end of the front propeller shaft 18 is slid (FIG. 8) during a collision.
Of the stub shaft 18a and the inner ring 84-2 of the DOJ portion 84 can be improved. If the collision force is large enough to cancel the combined state, only the stub shaft 18a slides (see S2 in FIG. 8) until the stub shaft 18a abuts on the second concave portion 148, and the impact at the time of collision is more efficiently reduced. It can be absorbed and alleviated, which can contribute to improvement of safety.

[0068]

As described above in detail, according to the present invention, there is provided an internal combustion engine having a propeller shaft having one end connected to a transmission connected to the internal combustion engine and the other end connected to a differential gear mechanism. At the one end side of the propeller shaft, there is provided a cylindrical connecting portion that allows sliding movement of one end side of the propeller shaft at the time of collision. The slide movement of the side can be allowed, and the impact at the time of collision can be efficiently absorbed and mitigated, so that safety can be improved.

[Brief description of the drawings]

FIGS. 1A and 1B show a shock absorbing propeller shaft according to a first embodiment of the present invention, wherein FIG. 1A is a schematic enlarged sectional view of a cylindrical connecting portion of the propeller shaft taken along an axial direction, and FIG. FIG. 4 is a schematic enlarged cross-sectional view of a cylindrical connecting portion cut along a width direction.

FIG. 2 is a schematic plan view of the vehicle.

FIG. 3 is a schematic configuration diagram of a transmission.

FIG. 4 is a sectional view of a chain portion of the transmission.

FIG. 5 is a cross-sectional view of a shock absorbing propeller shaft taken along an axial direction.

6A and 6B show a shock absorbing propeller shaft according to a second embodiment of the present invention, wherein FIG. 6A is a schematic enlarged cross-sectional view of a cylindrical connecting portion of the propeller shaft taken along an axial direction, and FIG. FIG. 4 is a schematic enlarged cross-sectional view of a cylindrical connecting portion cut along a width direction.

7A and 7B show a shock absorbing propeller shaft according to a third embodiment of the present invention, wherein FIG. 7A is a schematic enlarged sectional view of a cylindrical connecting portion of the propeller shaft taken along an axial direction, and FIG. FIG. 4 is a schematic enlarged cross-sectional view of a cylindrical connecting portion cut along a width direction.

FIG. 8 is a schematic enlarged sectional view showing a cylindrical connecting portion of a shock absorbing propeller shaft according to another first embodiment of the present invention, taken along an axial direction.

FIG. 9 is a schematic configuration diagram of a transmission showing the prior art of the present invention.

FIG. 10 is a schematic enlarged sectional view of a transfer side of a propeller shaft.

11A and 11B show a conventional example of a propeller shaft, FIG. 11A is a schematic diagram of a propeller shaft of a first conventional example, and FIG.
FIG. 3C is a schematic view of a propeller shaft of a conventional example, and FIG. 3C is a schematic view of a propeller shaft of a third conventional example.

[Explanation of symbols]

 2 vehicle 4 internal combustion engine 6 transmission 8 transfer 16 front differential gear mechanism 18 front propeller shaft 20 rear differential gear mechanism 22 rear propeller shaft 24 front wheel 26 front wheel shaft 28 rear wheel 30 rear wheel shaft 32 transmission case 34 input shaft 36 counter shaft Reference Signs List 38 output shaft 40 transmission gear train 70 transfer drive sprocket 72 transfer output shaft 74 transfer driven sprocket 76 transfer chain 78, 80 bearing 82 cylindrical connecting part 84 DOJ (double offset joint) part 86 cylindrical part 88 sealing member 90 mounting member 92 Grease cover 94 Bolt 98 Flange part 100 Spline fitting part 102 Tightening Tsu door

Claims (4)

[Claims] 1. An internal combustion engine having a propeller shaft having one end connected to a transmission connected to the internal combustion engine and the other end connected to a differential gear mechanism. An impact-absorbing propeller shaft structure comprising a cylindrical connecting portion that allows sliding movement of one end of the shaft. 2. A front propeller shaft having one end connected to a transmission connected to an internal combustion engine via a transfer output shaft of a transfer, and the other end connected to a front differential gear mechanism. A rear propeller shaft connecting one end to a transmission connected to the engine via a transfer and connecting the other end to a rear differential gear mechanism,
2. The shock absorbing propeller shaft structure according to claim 1, wherein a spline fitting portion between the sprocket of the transfer and the transfer output shaft is provided between two bearings supporting the sprocket and on the inner diameter side of the sprocket. 3. The transfer according to claim 1, wherein the transfer sprocket and the transfer output shaft are spline-fitted to each other, and a tightening nut for tightening and fixing the transfer output shaft on a side away from the front propeller shaft, which is a vehicle rear side, is provided. The shock absorbing propeller shaft structure according to claim 2. 4. A front propeller shaft having one end connected to a transmission connected to an internal combustion engine via a transfer output shaft of the transfer, and the other end connected to a front differential gear mechanism. And a rear propeller shaft connected at one end to a transmission connected to the transmission via a transfer, and connected at the other end to a rear differential gear mechanism, when the front propeller shaft of the transfer output shaft collides with the front propeller shaft. 2. The shock absorbing propeller shaft structure according to claim 1, further comprising: a first concave portion that allows one end to slide, and a second concave portion that allows the front propeller shaft end to slide. .