Power transmission shaft and propeller shaft

Abstract

The present invention is related to a propeller shaft (PS1) that is a power transmission shaft, in which a first collapse length (S1) of a first joint member (J1) that bends on the basis of a first bending load is set to be longer than a second collapse length (S2) of a second joint member (J2) that bends on the basis of a second bending load that is greater than the first bending load. As a result, even when an axial load is applied from the first end portion (11) side, the second end portion (12) side, or both of the first end portion (11) side and the second end portion (12) side, the second joint member (J2) can be smoothly inserted into a tube (1), and the collision performance of the propeller shaft (PS1) can be stabilized.

Description

Power transmission shaft and propeller shaft

[0001] The present invention relates to a power transmission shaft and a propeller shaft.

[0002] A known example of a propeller shaft, which is a conventional power transmission shaft, is disclosed in Patent Document 1 below.

[0003] To explain briefly, the propeller shaft serving as the power transmission shaft has a first shaft portion pressed into the first end of the tube, which is connected to a constant velocity joint that is relatively easy to bend, and a second shaft portion pressed into the second end of the tube, which is connected to a rubber coupling that is relatively difficult to bend.

[0004] Japanese Patent Application Laid-Open No. 2021-138203

[0005] However, in the conventional propeller shaft, no consideration was given to the length by which the first shaft portion connected to the flexible constant velocity joint extends into the tube (first collapse length) and the length by which the second shaft portion connected to the less flexible rubber coupling extends into the tube (second collapse length).This resulted in unstable crash performance of the propeller shaft, leaving room for improvement.

[0006] Therefore, the present invention was devised in consideration of the technical problems with the conventional propeller shafts, and aims to provide a power transmission shaft and a propeller shaft that can improve the stability of collision performance.

[0007] In one aspect of the present invention, a first collapse length, over which a first shaft portion of a first coupling member that can be bent by a first bending load enters into an inner peripheral portion of a tube, is set to be longer than a second collapse length, over which a second shaft portion of a second coupling member that has a bending load greater than the first bending load enters into an inner peripheral portion of a tube.

[0008] According to the present invention, it is possible to improve the stability of collision performance.

[0009] 1 is a layout diagram showing the arrangement of a power transmission shaft (propeller shaft) according to the present invention in a vehicle. 2 is a semi-longitudinal cross-sectional view showing the entire power transmission shaft (propeller shaft) according to a first embodiment of the present invention. 3 is a semi-longitudinal cross-sectional view showing a state in which a collision load is input from the front to the power transmission shaft (propeller shaft) shown in FIG. 2, where (a) shows a state in which no collapse occurs, (b) shows a state in which collapse occurs on the first end side of the tube, and (c) shows a state in which collapse occurs on the second end side of the tube. 4 is a semi-longitudinal cross-sectional view showing a state in which a collision load is input from the rear to the power transmission shaft (propeller shaft) shown in FIG. 2, where (a) shows a state in which no collapse occurs, (b) shows a state in which collapse occurs on the second end side of the tube, and (c) shows a state in which collapse occurs on the first end side of the tube. 3A and 3B are semi-longitudinal cross-sectional views showing a state in which a collision load is input to the power transmission shaft (propeller shaft) shown in FIG. 2 from the front-rear direction, where (a) shows a state in which no collapse occurs and (b) shows a state in which collapse occurs at the first end side and the second end side of the tube.

[0023] Fig. 3A is a schematic diagram explaining the effects of the present invention when collapse occurs from the first end side, where (a) shows the collapsed state of the power transmission shaft (propeller shaft) according to the present invention and (b) shows the collapsed state of a conventional power transmission shaft (propeller shaft). 3B is a schematic diagram explaining the effects of the present invention when collapse occurs from the second end side, where (a) shows the collapsed state of the power transmission shaft (propeller shaft) according to the present invention and (b) shows the collapsed state of the conventional power transmission shaft (propeller shaft). 1 is a schematic diagram illustrating the effects of the present invention when collapse occurs from both the first end and the second end, where (a) is a diagram illustrating a collapsed state of the power transmission shaft (propeller shaft) according to the present invention, and (b) is a diagram illustrating a collapsed state of a conventional power transmission shaft (propeller shaft). FIG. 2 is a semi-longitudinal cross-sectional view illustrating the entire power transmission shaft (propeller shaft) according to a second embodiment of the present invention. FIG. 3 is a semi-longitudinal cross-sectional view illustrating the entire power transmission shaft (propeller shaft) according to a third embodiment of the present invention. FIG. 4 is a layout diagram illustrating another example of the arrangement of the power transmission shaft (propeller shaft) according to the present invention in a vehicle.

[0010] Hereinafter, embodiments of a power transmission shaft (propeller shaft) according to the present invention will be described in detail with reference to the drawings. In the following embodiments, the power transmission shaft (propeller shaft) will be described as being applied to a propeller shaft for an automobile, as in the conventional case.

[0011] FIG. 1 shows a layout diagram illustrating the arrangement of a power transmission shaft (propeller shaft) according to the present invention in a vehicle.

[0012] As shown in Figure 1, vehicle V is a so-called FR (front engine, rear drive) vehicle, in which an engine EG and a transmission TM serving as a first power transmission device (transmission) that transmits the driving force of the engine EG are disposed on a front axle FD that connects the front wheels FT. Meanwhile, a differential DF serving as a second power transmission device (differential) that transmits power to the rear axle RD is disposed in the center of a rear axle RD that connects the rear wheels RT. The transmission TM and the differential DF are connected to each other via a propeller shaft PS that serves as a power transmission shaft so that power can be transmitted.

[0013] 2 to 8 show a first embodiment of a power transmission shaft according to the present invention. For convenience, the left side of Fig. 2 will be referred to as the "front" and the right side as the "rear" in the description of this embodiment. Furthermore, the direction along the rotation axis Z in Fig. 2 will be referred to as the "axial direction," the direction perpendicular to the rotation axis Z as the "radial direction," and the direction around the rotation axis Z as the "circumferential direction."

[0014] (Configuration of Propeller Shaft) FIG. 2 shows the overall configuration of the propeller shaft PS1 according to the first embodiment of the present invention, and shows a half cross-sectional view of the propeller shaft PS1 cut along the direction of the rotation axis Z.

[0015] 2, the propeller shaft PS1 is disposed between a first power transmission device P1 disposed at the front of the vehicle and a second power transmission device P2 disposed at the rear of the vehicle. In this embodiment, the first power transmission device P1 corresponds to a transmission TM, which is a speed change device, and the second power transmission device P2 corresponds to a differential DF, which is a differential device.

[0016] That is, the propeller shaft PS1 according to this embodiment is a so-called one-piece propeller shaft, and its front end is connected to the first power transmission device P1 via a first joint member J1, and its rear end is connected to the second power transmission device P2 via a second joint member J2. That is, the propeller shaft PS1 has a tube 1 formed in a generally cylindrical shape, a first joint member J1 that is inserted into a first end 11, which is the front end of the tube 1, and serves to connect to the first power transmission device P1, and a second joint member J2 that is inserted into a second end 12, which is the rear end of the tube 1, and serves to connect to the second power transmission device P2.

[0017] The tube 1 is made of carbon fiber reinforced resin (CFRP) material, which is made by solidifying carbon fibers with resin, and is formed into a cylindrical shape having a constant inner diameter R1 in the axial direction. Furthermore, the tube 1 is formed such that the wall thicknesses T1, T2 of the first end 11 and the second end 12 are thicker than the wall thickness T3 of the general portion (axial middle portion). Specifically, the tube 1 is integrally formed by laminating the carbon fiber reinforced resin (CFRP) material in the radial direction, and is formed into at least two layers, an inner layer 13 and an outer layer 14.

[0018] In this embodiment, the tube 1 is formed from carbon fiber reinforced resin (CFRP), but the tube 1 may be formed from a fiber reinforced resin formed by solidifying fibers with resin, or from a metal material, for example. When the tube 1 is formed from a fiber reinforced resin, it may be formed from, for example, glass fiber reinforced resin (FRP) formed by solidifying glass fibers with resin, in addition to the carbon fiber reinforced resin (CFRP) according to this embodiment.

[0019] The first joint member J1 has a first shaft portion 2 that is inserted into the inner periphery 111 of the first end portion 11 of the tube 1, and a first joint portion 4 that connects the first shaft portion 2 to the first power transmission device P1. The first shaft portion 2 and the first joint portion 4 are fixed so as to be rotatable together, and are integrally configured as the first joint member J1.

[0020] The second joint member J2 has a second shaft portion 3 that is inserted into the inner periphery 121 of the second end portion 12 of the tube 1, and a second joint portion 5 that connects the second shaft portion 3 to the second power transmission device P2. The second shaft portion 3 and the second joint portion 5 are fixed so as to be rotatable together, and are integrally configured as the second joint member J2.

[0021] The first shaft portion 2 has a first connection base portion 21 exposed from the first end portion 11 of the tube 1 and connected to the first joint portion 4, and a first insertion portion 22 extending in the axial direction from the rear end portion of the first connection base portion 21 and inserted into the inner periphery 111 of the first end portion 11 of the tube 1. The first connection base portion 21 and the first insertion portion 22 are integrally formed from a metal material.

[0022] The first connection base 21 has a first base 23, a first insertion-side connection portion 24 whose diameter increases in a stepped manner from the rear end of the first base 23 and is connected to the first insertion portion 22, and a first joint-side connection portion 25 whose diameter decreases in a stepped manner from the front end of the first base 23 and is connected to the first joint portion 4. The first connection base 21 and the first joint portion 4 constitute the first main body portion according to the present invention.

[0023] The first insertion portion 22 is inserted into the inner peripheral portion 111 of the first end 11 of the tube 1 via a predetermined engagement means (serrations in this embodiment) and is fixed so as to be rotatable integrally with the tube 1. Specifically, the first insertion portion 22 has a first serration portion 26 formed on the outer peripheral side thereof over almost the entire axial length, which can be serrated coupled to the tube 1.

[0024] The first serration portion 26 is formed so that grooves 261 recessed radially inward extend in a direction parallel to the rotation axis Z, and the outer diameter D1 of the tooth tips 262 is set to be slightly larger than the inner diameter R1 of the tube 1. In other words, the first serration portion 26 engages the first insertion portion 22 and the tube 1 so that they can rotate together as a unit when the first insertion portion 22 is press-fitted into the first end 11 of the tube 1 and the tooth tips 262 bite into the inner circumferential surface of the tube 1. As a result, the first insertion portion 22 is fixedly supported via the first serration portion 26 at the inner circumferential portion 111 of the first end 11 of the tube 1.

[0025] A first collision load F1 is set between the first serration portion 26 and the tube 1, as a holding load at which the first insertion portion 22 releases the fixed state with the tube 1 and starts to move along the inner periphery of the tube 1 from the first end 11 toward the second end 12. The first collision load F1 can be set based on any meshing element, such as the meshing length L1 of the first serration portion 26 meshing with the inner periphery 111 of the first end 11 of the tube 1 or the meshing allowance X1.

[0026] The first joint portion 4 is configured by a universal joint (for example, a constant velocity joint in this embodiment), and is provided on the opposite side of the first shaft portion 2 in the axial direction of the tube 1. That is, the first joint portion 4 has a generally cylindrical inner ring member 41 fixed to the outer peripheral surface of the first joint-side connecting portion 25 of the first shaft portion 2, a generally cylindrical outer ring member 42 arranged opposite the outer peripheral side of the inner ring member 41, and a plurality of balls 43 as rolling elements arranged to be able to roll between the outer ring member 42 and the inner ring member 41.

[0027] Furthermore, the first joint portion 4 is configured so that the outer diameter D3 of the outer ring member 42 is larger than the outer diameter D1 of the first insertion portion 22. Specifically, when the first shaft portion 2 slides into the tube 1 during a frontal collision of the vehicle, the head 60 of the bolt 6 that is threaded into the first joint portion 4 from the tube 1 side and fastened to the first power transmission device P1 comes into contact with the end face (first end face 112) on the first end portion 11 side of the tube 1.

[0028] In this embodiment, a first collapse length S1, which is the length of the tube 1 that penetrates into the inner periphery 111 of the first end 11 of the tube 1 when a collapse occurs (described below), is set by the distance between the first end face 112 of the tube 1 and the head 60 of the bolt 6. The first collapse length S1 is set to be longer than a second collapse length S2 (described below). Specifically, the first collapse length S1 is set to be approximately twice the second collapse length S2 (described below). The first collapse length S1 may be adjusted by the axial dimension of the first connection base 21 or the axial dimension of the head 60 of the bolt 6.

[0029] A generally circular shaft through hole 411, through which the first joint-side connecting portion 25 passes, penetrates along the axial direction on the inner peripheral side of the inner ring member 41. In other words, the first joint-side connecting portion 25 is press-fitted into the shaft through hole 411 over almost the entire axial area, and the first joint-side connecting portion 25 and the inner ring member 41 are fixed so as to be rotatable together.

[0030] Furthermore, an inner ring side axial groove 412 in which the balls 43 can roll is formed along the axial direction on the outer peripheral side of the inner ring member 41. That is, the balls 43 roll between the inner ring side axial groove 412 and an outer ring side axial groove 421 (described later), thereby allowing relative axial movement between the inner ring member 41 and the outer ring member 42, while the balls 43 engage with the inner ring side axial groove 412 and the outer ring side axial groove 421, thereby restricting relative circumferential movement between the inner ring member 41 and the outer ring member 42.

[0031] The outer ring member 42 is fixed to the first power transmission device P1 so as to be rotatable together with the first power transmission device P1 via a plurality of bolts 6 that axially penetrate the outer ring member 42. Furthermore, an outer ring side axial groove 421, in which the balls 43 can roll, is formed along the axial direction on the inner peripheral side of the outer ring member 42. That is, the balls 43 roll between the outer ring side axial groove 421 and the inner ring side axial groove 412, allowing relative movement in the axial direction between the outer ring member 42 and the inner ring member 41, while the balls 43 engage with the outer ring side axial groove 421 and the inner ring side axial groove 412, restricting relative movement in the circumferential direction between the outer ring member 42 and the inner ring member 41.

[0032] With this configuration, the first power transmission device P1 and the outer ring member 42 rotate together, and the rotational torque output from the first power transmission device P1 is transmitted from the outer ring member 42 to the inner ring member 41 via the balls 43. Then, based on this transmitted rotational torque, the inner ring member 41 and the first shaft portion 2 (first connection base portion 21) rotate together.

[0033] The second shaft portion 3 has a second connection base portion 31 exposed from the second end portion 12 of the tube 1 and connected to the second joint portion 5, and a second insertion portion 32 extending axially from the front end portion of the second connection base portion 31 and inserted into the inner periphery 121 of the second end portion 12 of the tube 1. The second connection base portion 31 and the second insertion portion 32 are integrally formed from a metal material.

[0034] The second connection base 31 has a second base 33, a second insertion side connection portion 34 whose diameter increases in a stepped manner from the front end of the second base 33 and is connected to the second insertion portion 32, and a second joint side connection portion 35 whose diameter increases in a stepped manner from the rear end of the second base 33 and is connected to the second joint portion 5. The second connection base 31 and the second joint portion 5 constitute the second main body portion according to the present invention.

[0035] The second insertion portion 32 is inserted into the inner peripheral portion 121 of the second end portion 12 of the tube 1 via a predetermined engagement means (serrations in this embodiment) and is fixed so as to be rotatable integrally with the tube 1. Specifically, the second insertion portion 32 has a second serration portion 36 formed on the outer peripheral side thereof over almost the entire axial length, which can be serrated coupled to the tube 1.

[0036] In this embodiment, the axial dimension of the second serration portion 36 is set to be approximately the same as the axial dimension of the first serration portion 26. In other words, the second bite length L2 set by the axial dimension of the second serration portion 36 is set to be approximately the same as the first bite length L1 set by the axial dimension of the first serration portion 26.

[0037] The second serration portion 36 is formed so that grooves 361 recessed radially inward extend in a direction parallel to the rotation axis Z, and the outer diameter D2 of the tooth tips 362 is set to be slightly larger than the inner diameter R1 of the tube 1. In other words, the second serration portion 36 engages the second insertion portion 32 and the tube 1 so that they can rotate together as a unit when the second insertion portion 32 is press-fitted into the second end 12 of the tube 1 and the tooth tips 362 bite into the inner circumferential surface of the tube 1. As a result, the second insertion portion 32 is fixedly supported via the second serration portion 36 on the inner circumferential portion 121 of the second end 12 of the tube 1.

[0038] In this embodiment, the outer diameter D2 of the tooth tip 362 of the second serration portion 36 is set to be approximately the same as the outer diameter D1 of the tooth tip 262 of the first serration portion 26. In other words, in this embodiment, the second engagement amount X2 of the second serration portion 36 is set to be approximately the same as the first engagement amount X1 of the first serration portion 26.

[0039] A second collision load F2 is set between the second serration portion 36 and the tube 1, at which the second insertion portion 32 releases the fixed state with the tube 1 and begins to move along the inner periphery of the tube 1 from the second end 12 toward the first end 11. Similar to the first collision load F1, the second collision load F2 can also be set based on any meshing element, such as the meshing length L2 or meshing margin X2 of the second serration portion 36 meshing with the inner periphery 121 of the second end 12 of the tube 1.

[0040] In this embodiment, the second bite length L2 and second bite width X2 of the second serration portion 36 are set to be the same as the first bite length L1 and first bite width X1 of the first serration portion 26, and therefore the second collision load F2 is set to be approximately the same as the first collision load F1.

[0041] The second joint portion 5 is configured as a so-called rubber coupling, and is provided on the opposite side of the second shaft portion 3 in the axial direction of the tube 1. That is, the second joint portion 5 is substantially annular, and has three first bolt through holes 51 arranged at equal intervals in the circumferential direction and used for connection to the second joint-side connecting portion 35 of the second shaft portion 3, and three second bolt through holes 52 arranged at equal intervals in the circumferential direction between the first bolt through holes 51 and used for connection to the second power transmission device P2.

[0042] That is, the trident-shaped second joint-side connecting portion 35 and the second joint portion 5 are fastened and fixed so as to be rotatable together via a first bolt 61 that passes through the first bolt through-hole 51. On the other hand, the trident-shaped second power transmission device P2 and the second joint portion 5 are fastened and fixed so as to be rotatable together via a second bolt (not shown) that passes through the second bolt through-hole 52.

[0043] In this embodiment, the second joint portion 5 is configured by a rubber coupling as described above. Therefore, the second joint portion 5 is more difficult to bend than the first joint portion 4 configured by the constant velocity joint. That is, the second joint portion 5 has a second bending load B2, which is a load required when the second joint portion 5 bends about the rotation axis Z, that is greater than the first bending load B1, which is a load required when the first joint portion 4 bends about the rotation axis Z. In other words, the propeller shaft PS1 is configured such that the first joint portion 4 bends at a relatively large first bending angle θ1 with respect to the rotation axis Z, and the second joint portion 5 bends at a relatively small second bending angle θ2 with respect to the rotation axis Z (see FIGS. 3( a), 4( a), and 5( a)).

[0044] The second joint portion 5 is configured so that an outer diameter D4 of the second joint portion 5 is larger than an outer diameter D2 of the second insertion portion 32. Specifically, when the second shaft portion 3 slides into the tube 1 during a rearward collision of the vehicle, the inner end face 351 of the second joint-side connecting portion 35 can come into contact with the end face (second end face 122) on the second end 12 side of the tube 1. In this embodiment, a second collapse length S2 by which the second shaft portion 3 slides into the inner periphery 121 of the second end 12 of the tube 1 during a collapse, which will be described later, is set by the distance between the second end face 122 of the tube 1 and the inner end face 351 of the second joint-side connecting portion 35.

[0045] (Collapse Structure of Propeller Shaft) The collapse structure of the propeller shaft PS1 according to this embodiment will be described below with reference to Figures 3 to 5. Note that, hereinafter, "collapse" refers to a situation in which, due to an axial load Fx being input to the propeller shaft PS1, the fixed state of the first insertion portion 22 and the second insertion portion 32 relative to the tube 1 is released (destroyed), and the first shaft portion 2 (first connection base portion 21) and the second shaft portion 3 (second connection base portion 31) slide into the interior of the tube 1.

[0046] The axial load Fx is buffered and the collision energy of the vehicle is absorbed by the collapse occurring at the first end 11 side or the second end 12 side of the tube 1. In other words, the first connection base 21 or the second connection base 31 normally slides into the interior of the tube 1, thereby normally buffering the axial load Fx and preventing problems such as bending of the propeller shaft PS1 toward the vehicle body.

[0047] 3A and 3B are semi-longitudinal cross-sectional views showing a state in which a collision load is input from the front to the power transmission shaft shown in FIG. 2, in which (a) shows a state in which no collapse occurs, (b) shows a state in which collapse occurs on the first end 11 side of the tube, and (c) shows a state in which collapse occurs on the second end 12 side of the tube.

[0048] As shown in Figure 3, when a vehicle collides from the front and a compressive axial load Fx greater than the first collision load F1 acts from the front end of the propeller shaft PS1, the axial load Fx is transmitted from the first power transmission device P1 to the first shaft portion 2 via the first joint portion 4. Then, from the normal state shown in Figure 3(a), collapse first occurs on the first end portion 11 side of the tube 1.

[0049] Specifically, when an axial load Fx greater than the first collision load F1 is input between the first shaft portion 2 and the tube 1, the fixed state between the first end 11 of the tube 1 and the first insertion portion 22 is released (destroyed), and the first connection base portion 21 slides into the inner periphery 111 of the first end 11 of the tube 1, as shown in Figure 3(b) . Specifically, the first insertion portion 22 moves from the first end 11 toward the second end 12 in the inner periphery 111 of the first end 11 of the tube 1 until the head 60 of the bolt 6 of the first joint portion 4 abuts against the first end face 112 of the tube 1.

[0050] Next, an axial load Fx is transmitted from the first shaft portion 2 to the second shaft portion 3 via the tube 1, and the axial load Fx is applied to the second shaft portion 3, which is sandwiched between the tube 1 and the second power transmission device P2, by a reaction. Then, with a delay from the collapse on the first end portion 11 side, collapse occurs on the second end portion 12 side of the tube 1.

[0051] That is, when an axial load Fx greater than the second collision load F2 is input between the second shaft portion 3 and the tube 1, the fixed state between the second end 12 of the tube 1 and the second insertion portion 32 is released (destroyed), as shown in Fig. 3(c), and the second connection base 31 slides into the second end 12 of the tube 1. Specifically, at the second end 12 of the tube 1, the second insertion portion 32 moves from the second end 12 toward the first end 11 until the inner end surface 351 of the second joint-side connection portion 35 abuts against the second end surface 122 of the tube 1.

[0052] 4A and 4B are semi-longitudinal cross-sectional views showing a state in which a collision load is input from behind to the power transmission shaft shown in FIG. 2, in which (a) shows a state in which no collapse occurs, (b) shows a state in which collapse occurs on the second end 12 side of the tube, and (c) shows a state in which collapse occurs on the first end 11 side of the tube.

[0053] As shown in Figure 4, when a vehicle collides from behind and a compressive axial load Fx greater than the second collision load F2 acts from the rear end of the propeller shaft PS1, the axial load Fx is transmitted from the second power transmission device P2 to the second shaft portion 3 via the second joint portion 5. Then, first, collapse occurs on the second end portion 12 side of the tube 1 from the normal state shown in Figure 4(a).

[0054] Specifically, when an axial load Fx greater than the second collision load F2 is input between the second shaft portion 3 and the tube 1, the fixed state between the second end 12 of the tube 1 and the second insertion portion 32 is released (broken) as shown in Fig. 4(b), and the second connection base 31 slides into the inner circumferential portion 121 of the second end 12 of the tube 1. Specifically, the first insertion portion 22 moves from the first end 11 toward the second end 12 in the inner circumferential portion 121 of the second end 12 of the tube 1 until the inner end surface 351 of the second joint-side connection portion 35 abuts against the second end surface 122 of the tube 1.

[0055] Next, the axial load Fx is transmitted from the second shaft portion 3 to the first shaft portion 2 via the tube 1, and the axial load Fx acts on the first shaft portion 2, which is sandwiched between the tube 1 and the first power transmission device P1, due to a reaction. Then, with a delay after the collapse on the second end 12 side, collapse occurs on the first end 11 side of the tube 1.

[0056] That is, when an axial load Fx greater than the first collision load F1 is input between the first shaft portion 2 and the tube 1, the fixed state between the first end 11 of the tube 1 and the first insertion portion 22 is released (destroyed), as shown in Fig. 4(c), and the first connection base 21 slides into the first end 11 of the tube 1. Specifically, the first insertion portion 22 moves from the first end 11 toward the second end 12 in the inner periphery 111 of the first end 11 of the tube 1 until the head 60 of the bolt 6 of the first joint portion 4 abuts against the first end face 112 of the tube 1.

[0057] 5A and 5B are semi-longitudinal cross-sectional views showing a state in which a collision load is input from the front-to-rear direction to the power transmission shaft shown in FIG. 2, where (a) shows a state in which no collapse has occurred, and (b) shows a state in which collapse has occurred on both the first end 11 side and the second end 12 side of the tube.

[0058] As shown in Figure 5, when a vehicle collides in the longitudinal direction and a compressive axial load Fx greater than the first collision load F1 and the second collision load F2 acts from the front and rear ends of the propeller shaft PS1, the axial load Fx is transmitted from the first power transmission device P1 and the second power transmission device P2 to the first shaft portion 2 and the second shaft portion 3 via the first joint portion 4 and the second joint portion 5. Then, from the normal state shown in Figure 5(a), collapse occurs simultaneously on the first end portion 11 side and the second end portion 12 side of the tube 1.

[0059] Specifically, when an axial load Fx greater than the first collision load F1 is input between the first shaft portion 2 and the tube 1, the fixed state between the first end 11 of the tube 1 and the first insertion portion 22 is released (broken) as shown in Fig. 4(b), and the first connection base 21 slides into the inner periphery 111 of the first end 11 of the tube 1. At the same time, when an axial load Fx greater than the second collision load F2 is input between the second shaft portion 3 and the tube 1, the fixed state between the second end 12 of the tube 1 and the second insertion portion 32 is released (broken) as shown in Fig. 4(b), and the second connection base 31 slides into the inner periphery 121 of the second end 12 of the tube 1.

[0060] Specifically, the first insertion portion 22 moves from the first end 11 toward the second end 12 at the inner periphery 111 of the first end 11 of the tube 1 until the head 60 of the bolt 6 of the first joint portion 4 abuts against the first end face 112 of the tube 1. At the same time, the second insertion portion 32 moves from the second end 12 toward the first end 11 at the inner periphery 121 of the second end 12 of the tube 1 until the inner end face 351 of the second joint-side connecting portion 35 abuts against the second end face 122 of the tube 1.

[0061] (Effects of the Present Embodiment) Fig. 6 is a schematic diagram illustrating the effects of the present invention when collapse occurs from the first end side, where (a) shows the collapsed state of the power transmission shaft according to the present invention and (b) shows the collapsed state of a conventional power transmission shaft. Fig. 7 is a schematic diagram illustrating the effects of the present invention when collapse occurs from the second end side, where (a) shows the collapsed state of the power transmission shaft according to the present invention and (b) shows the collapsed state of a conventional power transmission shaft. Fig. 8 is a schematic diagram illustrating the effects of the present invention when collapse occurs from both the first end and the second end, where (a) shows the collapsed state of the power transmission shaft according to the present invention and (b) shows the collapsed state of a conventional power transmission shaft.

[0062] In the conventional propeller shaft PS0, no consideration was given to the length between the first collapse length S1, which is the length by which the first shaft portion 2 connected to the first joint portion 4 formed by a constant velocity joint that is relatively easy to bend, extends into the tube 1, and the second collapse length S2, which is the length by which the second shaft portion 3 connected to the second joint portion 5 formed by a rubber coupling that is relatively difficult to bend, extends into the tube 1. For this reason, in a propeller shaft PS0 in which the second collapse length S2 is longer than the first collapse length S1, the crash performance of the propeller shaft PS0 becomes unstable, and there was room for improvement.

[0063] 6(b), when an axial load Fx is input from the front (the first end 11 side), collapse occurs first at the first end 11 side. As a result, the first insertion portion 22 of the first coupling member J1, which has a relatively small first bending load B1 and is relatively easy to bend, moves from the first end 11 side to the second end 12 side, the first connection base portion 21 enters the inside of the tube 1, and the first coupling part 4 abuts against the first end surface 112 of the tube 1. Here, when the first coupling part 4 and the tube 1 abut at an angle θ, a first moment M1 is generated in the first coupling part 4 so that the first coupling part 4 and the first end surface 112 of the tube 1 coincide with each other, and a second moment M2 is generated in the tube 1, which acts to lift the second end 12 side of the tube 1. As a result, in the propeller shaft PS0 in which the second collapse length S2 is longer than the first collapse length S1, an angle θ is formed between the second shaft portion 3 and the tube 1. This causes the second shaft portion 3 to get caught on the inner periphery 121 of the second end 12 of the tube 1, making it difficult for the second shaft portion 3 to enter the inside of the tube 1. As a result, there is a risk that the collision performance of the propeller shaft PS0 will deteriorate.

[0064] On the other hand, as shown in Figure 7(b), when an axial load Fx is input from the rear (the side of the second end 12), collapse occurs first at the side of the second end 12. In this case, in the propeller shaft PS0 in which the second collapse length S2 is longer than the first collapse length S1, the relatively longer second shaft portion 3 enters the inside of the tube 1 first. This allows the first shaft portion 2 to enter the inside of the tube 1 relatively smoothly, and does not deteriorate the crash performance of the propeller shaft PS0.

[0065] 8( b), when an axial load Fx is input from the front-rear direction (the first end 11 side and the second end 12 side), collapse occurs simultaneously on the first end 11 side and the second end 12 side. As a result, the first insertion portion 22 moves from the first end 11 side to the second end 12 side, and the first connection base portion 21 enters the inside of the tube 1. At the same time, the second insertion portion 32 moves from the second end 12 side to the first end 11 side, and the second connection base portion 31 enters the inside of the tube 1. Here, in the propeller shaft PS0 in which the second collapse length S2 is longer than the first collapse length S1, the first joint portion 4 comes into contact with the first end face 112 before the second joint portion 5 comes into contact with the second end face 122. As a result, the first joint portion 4, which has a relatively small first bending load B1, and the tube 1 abut at a relatively large angle θ, causing a first moment M1 to be generated in the first joint portion 4 so that the first joint portion 4 and the first end face 112 of the tube 1 coincide, and a second moment M2 to be generated in the tube 1, which acts to lift the second end 12 side of the tube 1. As a result, an angle θ is generated between the second shaft portion 3 and the tube 1, causing the second shaft portion 3 to get caught on the inner periphery 121 of the second end 12 of the tube 1, making it difficult for the second shaft portion 3 to enter the inside of the tube 1. As a result, the crash performance of the propeller shaft PS0 may be deteriorated.

[0066] In contrast, the propeller shaft PS1 according to this embodiment can solve the problems of the conventional propeller shafts by achieving the following advantageous effects.

[0067] The propeller shaft PS1 is a power transmission shaft (propeller shaft) that transmits power between a first power transmission device P1 and a second power transmission device P2 of a vehicle, and includes a tube 1 formed in a cylindrical shape, a first joint member that has a first main body portion (a first connection base portion 21 and a first joint portion 4) and a first insertion portion 22, and the first insertion portion 22 is a pair of ends in the direction of the rotation axis Z of the tube 1, a first end portion 11 and a second end portion 12, and the outer periphery of the first insertion portion 22 is fixedly supported by an inner periphery 111 of the first end portion 11. a first coupling member J1, in which, when an input load equal to or greater than a first collision load F1 acts, the fixed state with the tube 1 is released and the first insertion portion 22 is movable from the first end 11 toward the second end 12 of the tube 1, and the first main body portion (the first connection base 21 and the first joint portion 4) is provided on the opposite side of the first insertion portion 22 from the first end 11 in the direction of the rotation axis Z, and is connected to a first power transmission device P1 via the first joint portion 4 that is bendable in the direction of the rotation axis Z when a first bending load B1 acts on the first coupling member J1; The member has a second main body portion (second connection base portion 31 and second joint portion 5) and a second insertion portion 32, an outer periphery of the second insertion portion 32 is fixedly supported by an inner periphery 121 of the second end 12 of the tube 1, and when an input load equal to or greater than a second collision load F2 is applied, the fixed state with the tube 1 is released and the second insertion portion 32 is movable from the second end 12 to the first end 11 of the tube 1, and the second main body portion (second connection base portion 31 and second joint portion 5) is located closer to the second end 12 than the first end 11 in the direction of the rotation axis Z. and a second coupling member J2 that is provided on the opposite side of the second insertion portion 32 and is connected to the second power transmission device P2 via a second coupling section 5 in which a second bending load B2 required for bending in the direction of the rotation axis Z is set to be larger than the first bending load B1, and a first collapse length S1, which is the length by which the first coupling member J1 enters the inner circumferential portion 111 of the tube 1 when an input load acts on the first coupling member J1 and the second coupling member J2, is longer than a second collapse length S2, which is the length by which the second coupling member J2 enters the inner circumferential portion 121 of the tube 1.

[0068] As described above, in the propeller shaft PS1 according to this embodiment, the first collapse length S1 of the first joint part J1 that bends based on the first bending load B1 is set to be longer than the second collapse length S2 of the second joint part J2 that bends based on the second bending load B2 that is larger than the first bending load B1.

[0069] Therefore, when the front (first end 11) side collapses first, as shown in FIG. 6( a), when the first shaft portion 2 of the first coupling member J1, which is relatively flexible and has a relatively small first bending load B1, enters the tube 1, and when the first coupling portion 4 and the first end 11 of the tube 1 abut at an angle θ, a first moment M1 is generated in the first coupling portion 4 so that the first end face 112 of the tube 1 coincides with the first end face 112 of the tube 1, and a second moment M2 is generated in the tube 1, acting to lift the second end 12 side of the tube 1. As a result, the second shaft portion 3 is at an angle θ with respect to the tube 1, but because the second collapse length S2 is relatively shorter than the first collapse length S1, the second shaft portion 3 is more likely to enter the tube 1. This improves the stability of the crash performance of the propeller shaft PS1.

[0070] On the other hand, if the rear (second end 12 side) collapses first, as shown in Figure 7(a), the second bending load B2 is greater than the first bending load B1, and the second joint portion 5 is relatively difficult to bend. Therefore, when the second shaft portion 3 enters the inside of the tube 1, an angle is unlikely to form between the second shaft portion 3 and the tube 1, and even if the second joint portion 5 and the second end face 122 of the tube 1 come into contact so as to coincide, a large moment (first and second moments M1, M2) is not applied to the tube 1. As a result, an angle is unlikely to form between the first shaft portion 2 of the first joint member J1 and the tube 1, making it easier for the first shaft portion 2 to enter the inside of the tube 1, thereby improving the stability of the crash performance of the propeller shaft PS1.

[0071] On the other hand, when the first end 11 side and the second end 12 side collapse approximately simultaneously, as shown in FIG. 8( a), because the second collapse length S2 is set relatively shorter than the first collapse length S1, the second joint portion 5 comes into contact with the second end face 122 of the tube 1 before the first joint portion 4 comes into contact with the first end face 112 of the tube 1. Furthermore, at this time, the second bending load B2 is greater than the first bending load B1, and the second joint portion 5 is configured to be relatively difficult to bend. Therefore, even if the second joint portion 5 comes into contact with the second end face 122 of the tube 1 so as to coincide, a large moment (first and second moments M1, M2) does not act on the tube 1. As a result, an angle is unlikely to be formed between the first shaft portion 2 of the first joint member J1 and the tube 1, making it easier for the first shaft portion 2 to enter the interior of the tube 1, thereby improving the stability of the crash performance of the propeller shaft PS1.

[0072] In addition, in this embodiment, when an input load acts on the first joint part J1 and the second joint part J2, the first time period during which the first joint part 4 abuts against the first end part 11 of the tube 1 is longer than the second time period during which the second joint part 5 abuts against the second end part 12 of the tube 1.

[0073] As described above, in this embodiment, the first time period during which the first joint portion 4 abuts against the first end 11 of the tube 1 is longer than the second time period during which the second joint portion 5 abuts against the second end 12 of the tube 1. Therefore, when the second end 12 side collapses first, or when the first end 11 side and the second end 12 side collapse simultaneously, the second joint portion 5 abuts against the second end 12 of the tube 1 before the first joint portion 4 abuts against the first end 11 of the tube 1. In this case, even if the second joint portion 5 abuts against the second end face 122 of the tube 1 so as to coincide with each other, a large moment (first and second moments M1, M2) does not act on the tube 1. As a result, an angle is unlikely to be formed between the first shaft portion 2 of the first joint member J1 and the tube 1, making it easier for the first shaft portion 2 to penetrate into the tube 1, thereby improving the stability of the crash performance of the propeller shaft PS1.

[0074] In this embodiment, the first joint member J1 is connected to the first power transmission device P1 via a constant velocity joint.

[0075] As described above, in this embodiment, the first joint member J1 is connected to the first power transmission device P1 via the first joint portion 4 configured as a constant velocity joint. This has the advantage that the bending load varies less than when the first joint portion 4 is configured as a Cardan joint, making it easier to stabilize the collision performance of the propeller shaft PS1.

[0076] In addition, in this embodiment, the constant velocity joint (joint portion 4) is fastened to the first power transmission device P1 via a bolt 6 that is screwed from the tube 1 side toward the first power transmission device P1 side, and the first collapse length S1 is the distance from the first end 11 of the tube 1 to the head 60 of the bolt 6.

[0077] As described above, in this embodiment, the first joint portion 4, which is configured as a constant velocity joint, is fastened to the first power transmission device P1 via the bolts 6. Such bolt fastening is a general-purpose connecting means, which can reduce the manufacturing cost of the propeller shaft PS1 and improve the ease of installation of the propeller shaft PS1 to the vehicle V.

[0078] The first collapse length S1 is set by the distance from the first end 11 of the tube 1 to the head 60 of the bolt 6. Therefore, there is an advantage that the first collapse length S1 can be easily adjusted by adjusting the height of the head 60 of the bolt 6.

[0079] In addition, in this embodiment, the second joint member J2 is fastened to the second power transmission device P2 via a rubber coupling, and the second collapse length S2 is the distance from the second end 12 of the tube 1 to the yoke (second joint side connection portion 35) connected to the rubber coupling.

[0080] In this manner, in the present embodiment, the second joint member J2 is connected to the second power transmission device P2 via the second joint portion 5 formed by the rubber coupling. Therefore, the rubber coupling can absorb vibrations of the vehicle V, thereby improving the noise and vibration performance of the vehicle V.

[0081] The second collapse length S2 is set by the distance from the second end 12 of the tube 1 to the second joint-side connecting part 35, which is a yoke that connects to the rubber coupling. The rubber coupling (second joint part 5) forms a plane that extends in a direction perpendicular to the direction of the rotation axis Z, and so by abutting the plane of the rubber coupling (second joint part 5) against the second end face 122 of the tube 1, the stability of the collision performance of the propeller shaft PS1 is improved.

[0082] In addition, in this embodiment, the rotation axis of the first main body portion (first connection base portion 21 and first joint portion 4) is connected to the first power transmission device P1 at a first bending angle θ1 relative to the rotation axis Z of the tube 1, and the rotation axis of the second main body portion (second connection base portion 31 and second joint portion 5) is connected to the second power transmission device P2 at a second bending angle θ2 relative to the rotation axis Z of the tube 1, and the first bending angle θ1 is smaller than the second bending angle θ2.

[0083] As described above, in this embodiment, the first bending angle θ1 of the first joint part J1 is set smaller than the second bending angle θ2 of the second joint part J2. Normally, setting a large bending angle for a joint with a large bending load can result in the generation of acoustic vibrations. Therefore, by increasing the first bending angle θ1 of the first joint part J1, which has a relatively large bending load, and decreasing the second bending angle θ2 of the second joint part J2, which has a relatively small bending load, the generation of acoustic vibrations can be suppressed, thereby improving the acoustic vibration performance of the propeller shaft PS1.

[0084] Furthermore, if a large bending angle is applied to a joint that has a relatively large bending load, this large bending will generate a lot of heat, which may result in a loss of some of the power energy and a decrease in power transmission efficiency. Therefore, by increasing the first bending angle θ1 of the first joint part J1, which has a relatively large bending load, and decreasing the second bending angle θ2 of the second joint part J2, which has a relatively small bending load, it is possible to reduce the power energy lost due to bending of the second joint part J2, and improve the power transmission efficiency of the propeller shaft PS1.

[0085] In this embodiment, at least one of the first insertion portion 22 and the second insertion portion 32 is coupled to the inner periphery of the tube 1 via serrations.

[0086] As described above, in this embodiment, the first insertion portion 22 is coupled to the inner periphery 111 of the first end 11 of the tube 1 via the first serration portion 26, and the second insertion portion 32 is coupled to the inner periphery 121 of the second end 12 of the tube 1 via the second serration portion 36. This makes it possible to more firmly fix the first insertion portion 22 and the second insertion portion 32 compared to, for example, a case in which the first insertion portion 22 and the second insertion portion 32, each having a substantially flat outer periphery, are coupled to the inner periphery of the tube 1 simply by press-fitting or adhesive bonding. This ensures high torque resistance in the rotational direction of the propeller shaft PS1 and also enables a large holding load to be obtained in the axial direction of the propeller shaft PS1.

[0087] In addition, in this embodiment, the first power transmission device P1 is a transmission TM of the vehicle V, the second power transmission device P2 is a differential DF of the vehicle V, and the second joint member J2 is constituted by a rubber coupling.

[0088] As described above, in this embodiment, the second joint member J2 that connects the propeller shaft PS1 and the differential DF of the vehicle V is configured by a rubber coupling. This makes it possible for the rubber coupling to absorb and block vibrations from the differential DF, thereby improving the noise and vibration performance of the propeller shaft PS1.

[0089] In this embodiment, the tube 1 is made of a material formed by solidifying fibers with resin.

[0090] In this way, in this embodiment, the tube 1 is made of a fiber-reinforced resin material formed by solidifying fibers with resin, which makes it possible to reduce the weight of the tube 1 compared to when the tube 1 is made of a metal material, thereby contributing to improving the fuel efficiency of the automobile.

[0091] Furthermore, since the tube 1 is formed from the above-mentioned fiber-reinforced resin material, it is possible to reduce sound reverberation in the tube 1 compared to when the tube 1 is formed from a metal material, which can also contribute to improving the sound vibration performance of the propeller shaft PS1.

[0092] In particular, in this embodiment, the tube 1 is made of carbon fiber reinforced plastic (CFRP).

[0093] As described above, in this embodiment, since the tube 1 is formed from carbon fiber reinforced plastic (CFRP), the strength of the tube 1 is higher than that of other fiber reinforced plastics, such as glass fiber reinforced plastic (FRP), and the tube 1 can be made lighter.

[0094] As another example of this embodiment, the tube 1 can be made of glass fiber reinforced plastic (FRP) as described above. In this case, the tube 1 can be made more inexpensively than when the tube 1 is made of other fiber reinforced plastics, such as carbon fiber reinforced plastic (CFRP).

[0095] Second Embodiment Figure 9 shows a second embodiment of a power transmission shaft (propeller shaft) according to the present invention, in which the configuration of the first joint member J1 of the propeller shaft PS1 according to the first embodiment is modified. The basic configuration other than the modified points is the same as that of the first embodiment, and therefore, the same components as those in the first embodiment are denoted by the same reference numerals and will not be described again. For convenience, the left side of Figure 9 will be referred to as the "front" and the right side as the "rear" in the description of this embodiment. The direction along the rotation axis Z in Figure 9 will be referred to as the "axial direction," the direction perpendicular to the rotation axis Z as the "radial direction," and the direction around the rotation axis Z as the "circumferential direction."

[0096] (Configuration of Propeller Shaft) FIG. 9 shows the overall configuration of a propeller shaft PS2 according to a second embodiment of the present invention, and shows a half cross-sectional view of the propeller shaft PS2 cut along the direction of the rotation axis Z.

[0097] 9, in the propeller shaft PS2 according to this embodiment, the first joint portion 4 of the first joint member J1 is configured as a well-known Cardan joint rather than the constant velocity joint according to the first embodiment. That is, the first joint member J1 has a first yoke 71 connected to the transmission TM (see FIG. 1) corresponding to the first power transmission device P1, a second yoke 72 connected to the tube 1, and a cross shaft 73 disposed between the first yoke 71 and the second yoke 72.

[0098] The first yoke 71 has a bifurcated shape that faces radially, and first shaft insertion holes 710 are formed radially through the first yoke 71, into which a pair of first shaft portions 731 of the cross shaft 73 are inserted. The first yoke 71 is also formed integrally with a connecting shaft portion 74 that extends axially toward the transmission TM (see FIG. 1 ), and is connected to an output shaft (not shown) of the transmission TM via the connecting shaft portion 74.

[0099] The connecting shaft portion 74 has a vehicle-side connecting portion 741 that is connected to the output shaft (not shown) of the transmission TM via a spline, and a yoke-side connecting portion 742 that is provided at the rear end of the vehicle-side connecting portion 741 in a stepped diameter-enlarged form and is connected to the first yoke 71, the vehicle-side connecting portion 741 and the yoke-side connecting portion 742 being integrally formed. The vehicle-side connecting portion 741 is formed in a generally cylindrical shape and is inserted into a transmission case (not shown) of the transmission TM. A female spline portion 741a formed on the inner periphery is spline-coupled to a male spline portion provided on the outer periphery of the output shaft (not shown) of the transmission TM, thereby connecting them so as to be movable relative to each other in the axial direction.

[0100] The second yoke 72 has a bifurcated shape that faces radially, and second shaft insertion holes 720, into which the other pair of second shaft portions 732 of the cross shaft 73 are inserted, are formed radially through the second yoke 72 and are arranged alternately in the circumferential direction relative to the first yoke 71. The second yoke 72 is formed integrally with the first connection base 21 of the first shaft portion 2, and constitutes the first joint-side connection portion 25, which is connected to the tube 1 via the first insertion portion 22.

[0101] (Operation and Effect of the Present Embodiment) As described above, in the propeller shaft PS2 according to the present embodiment, the first joint member J1 is connected to the first power transmission device P1 (see FIG. 1) via a Cardan joint.

[0102] In this manner, in this embodiment, the first coupling member J1 is connected to the first power transmission device P1 via a Cardan joint, which has the advantage of reducing the manufacturing costs of the propeller shaft PS2 compared to when the first coupling member J1 is configured as a constant velocity joint.

[0103] Third Embodiment Figure 10 shows a third embodiment of a power transmission shaft (propeller shaft) according to the present invention, in which the configuration of the first insertion portion 22 and the second insertion portion 32 in the propeller shaft PS1 according to the first embodiment is modified. The basic configuration other than the modified points is the same as that of the first embodiment, and therefore the same components as those in the first embodiment are denoted by the same reference numerals and will not be described again. For convenience, the left side of Figure 10 will be referred to as the "front" and the right side as the "rear" in the description of this embodiment. The direction along the rotation axis Z in Figure 10 will be referred to as the "axial direction," the direction perpendicular to the rotation axis Z as the "radial direction," and the direction around the rotation axis Z as the "circumferential direction."

[0104] (Configuration of Propeller Shaft) FIG. 10 shows the overall configuration of a propeller shaft PS3 according to a third embodiment of the present invention, and shows a half cross-sectional view of the propeller shaft PS3 cut along the direction of the rotation axis Z.

[0105] 10 , in the propeller shaft PS3 according to this embodiment, the tube 1 is formed of a metal material. In the propeller shaft PS3, the first insertion portion 22 is spline-connected to the first end portion 11 of the tube 1, and the second insertion portion 32 is spline-connected to the second end portion 12 of the tube 1.

[0106] That is, a first female spline portion 15 having a well-known spline extending along the axial direction is formed on the inner peripheral portion 111 of the first end portion 11 of the tube 1. Meanwhile, a first male spline portion 27 having a well-known spline that meshes with the first female spline portion 15 of the tube 1 and is movable in the axial direction along the first female spline portion 15 is formed on the outer peripheral portion of the first insertion portion 22. The first insertion portion 22 is press-fitted into the first female spline portion 15 of the tube 1 via the first male spline portion 27.

[0107] Similarly to the first end 11, a second female spline portion 16 having a well-known spline extending along the axial direction is formed on the inner peripheral portion 121 of the second end 12 of the tube 1. Meanwhile, a second male spline portion 37 having a well-known spline that meshes with the second female spline portion 16 of the tube 1 and is movable axially along the second female spline portion 16 is formed on the outer peripheral portion of the second insertion portion 32 of the tube 1. The second insertion portion 32 is press-fitted into the second female spline portion 16 of the tube 1 via the second male spline portion 37.

[0108] (Operation and Effect of the Present Embodiment) As described above, in the propeller shaft PS3 according to the present embodiment, at least one of the first insertion portion 22 and the second insertion portion 32 is spline-coupled to the inner periphery of the tube 1 .

[0109] As described above, in this embodiment, both the first insertion portion 22 and the second insertion portion 32 are spline-connected to the inner periphery of the tube 1. Therefore, compared to when the first insertion portion 22 or the second insertion portion 32 is serrated-connected, it is possible to cause collapse with a smaller collision load. This makes it possible to control the occurrence of collapse and contribute to stabilizing the collision performance of the propeller shaft PS3.

[0110] In this embodiment, the tube 1 is made of a metal material.

[0111] In this way, in this embodiment, the tube 1 is made of a metal material, which makes it possible to form the tube 1 inexpensively, thereby contributing to reducing the manufacturing cost of the propeller shaft PS3.

[0112] In this embodiment, the first insertion portion 22 has a first male spline portion 27 that meshes with the first female spline portion 15 formed on the inner periphery of the tube 1 .

[0113] As described above, in this embodiment, the first insertion portion 22 is spline-coupled to the tube 1 via the first male spline portion 27 that meshes with the first female spline portion 15 of the tube 1. Therefore, compared to when the tube 1 is formed from fiber-reinforced resin, the propeller shaft PS3 can be manufactured relatively inexpensively, and there are advantages in that backlash between the first insertion portion 22 and the tube 1 at the first end 11 of the tube 1 can be reduced, resulting in good torque transmission from the first insertion portion 22 to the tube 1.

[0114] In this embodiment, the second insertion portion 32 has a second male spline portion 37 that meshes with the second female spline portion 16 formed on the inner periphery of the tube 1 .

[0115] As described above, in this embodiment, the second insertion portion 32 is spline-coupled to the tube 1 via the second male spline portion 37 that meshes with the second female spline portion 16 of the tube 1. Therefore, compared to when the tube 1 is formed from fiber-reinforced resin, the propeller shaft PS3 can be manufactured relatively inexpensively, and there are advantages in that backlash between the second insertion portion 32 and the tube 1 at the second end 12 of the tube 1 can be reduced, resulting in good torque transmission from the tube 1 to the second insertion portion 32.

[0116] The present invention is not limited to the configurations and aspects exemplified in the above-described embodiments, etc., and can be freely modified depending on the specifications and costs of the target application as long as the configuration can achieve the above-described effects of the present invention.

[0117] For example, in the above-described embodiments, the first power transmission device P1 is a transmission TM mounted on the vehicle, and the second power transmission device P2 is a differential DF mounted on the vehicle. However, as shown in FIG. 11 , the reverse configuration may also be used. Specifically, the present invention may be applied to a vehicle having a rear-engine, all-wheel drive drive system, or a vehicle having a drive system in which the engine EG and transmission TM are mounted at the rear of the vehicle, and the driving force of the engine EG output from the transmission TM is transmitted to the differential DF mounted at the front of the vehicle via a propeller shaft PS. In other words, the first power transmission device P1 may be the differential DF of the vehicle V, and the second power transmission device P2 may be the transmission TM of the vehicle V.

[0118] According to this modified example, the first joint member J1, which is relatively flexible, is connected to the differential DF, which has relatively large movement. Therefore, the movement of the differential DF is absorbed by the first joint member J1, which is relatively flexible, and the noise and vibration performance of the propeller shaft PS can be improved.

[0119] Furthermore, in the case of a vehicle in which the transmission TM is provided on the drive wheel (rear wheel) side, the first power transmission device P1 may be a drive source such as an engine, and the second power transmission device P2 may be the transmission TM, or vice versa.

[0120] The present invention can also be applied to a vehicle in which an electric motor is used as a continuously variable reducer in place of the transmission TM as the first power transmission device P1.

[0121] Furthermore, in each of the above embodiments, the first collision load F1 and the second collision load F2 are set to be equal by setting the first and second meshing lengths L1 and L2, and the first and second meshing margins X1 and X2 to be approximately equal. However, in addition to the relative relationship between the first collapse length S1 and the second collapse length S2, it is also possible to adjust the first collision load F1 and the second collision load F2 by providing a difference between the first and second meshing lengths L1 and L2, or the first and second meshing margins X1 and X2, and thereby control the timing of the collapse of the first joint part J1 and the second joint part J2, thereby improving the stability of the collision performance of the propeller shafts PS1, PS2, PS3.

Claims

1. A power transmission shaft that transmits power between a first power transmission device and a second power transmission device of a vehicle, A tube formed in a cylindrical shape; A first joint member having a first body portion and a first insertion portion, the first insertion portion is a pair of ends, a first end and a second end, in a direction of a rotation axis of the tube, an outer periphery of the first insertion portion is fixedly supported by an inner periphery of the first end, and when an input load equal to or greater than a first collision load acts on the tube, the fixed state with the tube is released and the first insertion portion is movable from the first end to the second end of the tube, the first main body portion is provided on the opposite side of the first insertion portion from the first end portion in the direction of the rotation axis, and is connected to the first power transmission device via a first joint portion that is bendable with respect to the direction of the rotation axis when a first bending load acts on the first main body portion; The first joint member; A second joint member having a second body portion and a second insertion portion, the second insertion portion is supported in a fixed state by an outer circumferential portion of the second end of the tube, and when an input load equal to or greater than a second collision load acts on the second insertion portion, the fixed state with the tube is released and the second insertion portion is movable from the second end of the tube toward the first end of the tube, the second main body portion is provided on the opposite side of the second insertion portion from the second end portion in the direction of the rotation axis, and is connected to the second power transmission device via a second joint portion in which a second bending load required when bending with respect to the direction of the rotation axis is set to be larger than the first bending load. The second joint member; Equipped with a first collapse length by which the first joint member penetrates into the inner circumferential portion of the tube when an input load acts on the first joint member and the second joint member is longer than a second collapse length by which the second joint member penetrates into the inner circumferential portion of the tube, When an input load acts on the first joint member and the second joint member, a first time during which the first joint portion abuts against the first end of the tube is longer than a second time during which the second joint portion abuts against the second end of the tube. A power transmission shaft characterized by:

2. 2. The power transmission shaft according to claim 1, The first coupling member is connected to the first power transmission device via a constant velocity joint. A power transmission shaft characterized by:

3. 3. The power transmission shaft according to claim 2, the constant velocity joint is fastened to the first power transmission device via a bolt that is screwed from the tube side toward the first power transmission device side, the first collapse length is the distance from the first end of the tube to the head of the bolt; A power transmission shaft characterized by:

4. 2. The power transmission shaft according to claim 1, the second coupling member is fastened to the second power transmission device via a rubber coupling, The second collapse length is the distance from the second end of the tube to a yoke that connects to the rubber coupling. A power transmission shaft characterized by:

5. 2. The power transmission shaft according to claim 1, a rotation axis of the first main body portion is connected to the first power transmission device at a first bending angle with respect to a rotation axis of the tube; a rotation axis of the second main body portion is connected to the second power transmission device at a second bend angle with respect to a rotation axis of the tube; The first bending angle is smaller than the second bending angle. A power transmission shaft characterized by:

6. 2. The power transmission shaft according to claim 1, the first coupling member is connected to the first power transmission device via a Cardan joint; A power transmission shaft characterized by:

7. 2. The power transmission shaft according to claim 1, At least one of the first insertion portion and the second insertion portion is coupled to an inner circumferential portion of the tube via serrations. A power transmission shaft characterized by:

8. 2. The power transmission shaft according to claim 1, At least one of the first insertion portion and the second insertion portion is splined to an inner periphery of the tube. A power transmission shaft characterized by:

9. 2. The power transmission shaft according to claim 1, the first power transmission device is a transmission of a vehicle; the second power transmission device is a vehicle differential; The second joint member is constituted by a rubber coupling. A power transmission shaft characterized by:

10. 2. The power transmission shaft according to claim 1, the first power transmission device is a differential of a vehicle; The second power transmission device is a vehicle transmission. A power transmission shaft characterized by:

11. 2. The power transmission shaft according to claim 1, The tube is made of a material formed by solidifying fibers with resin. A power transmission shaft characterized by:

12. 12. The power transmission shaft according to claim 11, The first insertion portion has a first male spline portion that meshes with a first female spline portion formed on an inner periphery of the tube. A power transmission shaft characterized by:

13. 2. The power transmission shaft according to claim 1, The tube is made of a metal material. A power transmission shaft characterized by:

14. 14. The power transmission shaft according to claim 13, The second insertion portion has a second male spline portion that meshes with a second female spline portion formed on an inner periphery of the tube. A power transmission shaft characterized by: