Power transmission shaft and propeller shaft

Abstract

A propeller shaft (PS1) according to the present invention is a power transmission shaft, and is configured such that when a second collision load (F2), which is greater than a first collision load (F1) at which an anchored condition of a first insertion section (22) and a tube (1) is released, has acted thereon, an anchored condition of a second insertion section (32) and the tube (1) is released. Thus, at the time of a vehicle collision, i.e. when an axial direction load (Fx) has acted on the propeller shaft (PS1), the anchored condition of the first insertion section (22) is released before that of the second insertion section (32), allowing the order of release of the anchoring of the first insertion section (22) and the second insertion section (32) to the tube (1) to be controlled. Consequently, stability in the collision performance of the propeller shaft (PS1) can be improved.

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 as a power transmission shaft has a first coupling member pressed into the inner periphery of a first end of an FRP cylindrical member, via a first insertion part having a first serration portion formed on the outer periphery, and a second insertion part pressed into the inner periphery of a second end of the FRP cylindrical member having a second serration portion formed on the outer periphery.

[0004] Japanese Patent Application Laid-Open No. 2000-329130

[0005] However, in the conventional propeller shaft, a first insertion portion and a second insertion portion, each having the same first serration portion and second serration portion formed thereon, are press-fitted into a first end portion and a second end portion of the FRP cylindrical body, respectively. This makes it difficult to predict which of the first end portion and the second end portion of the FRP cylindrical body will break first, i.e., which of the first insertion portion and the second insertion portion will penetrate into the FRP cylindrical body first, in the event of a vehicle collision. This makes the crash performance of the propeller shaft as a power transmission shaft unstable, and leaves 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, the second collision load that releases the fixed state between the tube and the second insertion portion is set to be greater than the first collision load that releases the fixed state between the tube and the first insertion portion.

[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 according to the present invention in a vehicle. FIG. 1 is a half-longitudinal sectional view showing the entire power transmission shaft according to a first embodiment of the present invention. FIG. 2 is an enlarged sectional view showing a main portion of the cross section along line A-A in FIG. 2. FIG. 2 is a view showing a modified power transmission shaft according to the present invention, and is an enlarged sectional view of a main portion taken along line A-A in FIG. 2. FIG. 1 is a half-longitudinal sectional view showing the states of the power transmission shaft shown in FIG. 2 before and after collapse occurs, where (a) is a state where no collapse occurs, (b) is a state where collapse occurs on the first end side of the tube, and (c) is a state where collapse occurs on the second end side of the tube. FIG. 2 is a half-longitudinal sectional view showing the entire power transmission shaft according to a second embodiment of the present invention. FIG. 3 is a half-longitudinal sectional view showing the entire power transmission shaft according to a third embodiment of the present invention. FIG. 4 is a half-longitudinal sectional view showing the entire power transmission shaft according to a fourth embodiment of the present invention. FIG. 5 is a half-longitudinal sectional view showing a power transmission shaft according to a fifth embodiment of the present invention, where (a) is an enlarged view of the vicinity of the first end of the tube, and (b) is an enlarged view of the vicinity of the second end of the tube. FIG. 3 is a layout diagram showing another example of the arrangement of a power transmission shaft according to the present invention in a vehicle.

[0010] Hereinafter, an embodiment of a power transmission shaft according to the present invention will be described in detail with reference to the drawings. In the following embodiment, the power transmission 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 5 show a first embodiment of a power transmission shaft according to the present invention. For convenience, in describing this embodiment, the first coupling member J1 side in FIG. 2 will be referred to as the "front" and the second coupling member J2 side as the "rear." 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 (not shown) disposed at the front of the vehicle and a second power transmission device (not shown) disposed at the rear of the vehicle. The first power transmission device corresponds to the transmission TM (see FIG. 1), which is a speed change device, and the second power transmission device corresponds to the differential DF (see FIG. 1), 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 via a first joint member J1 and its rear end is connected to the second power transmission device 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, 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.

[0017] Although the present embodiment illustrates an example in which the power transmission shaft (propeller shaft) according to the present invention is applied to a propeller shaft having the one-piece structure and a single tube, the present invention is applicable to a propeller shaft having at least one tube and having a collapsible coupling (described later) connected to both axial ends of the tube. In other words, the power transmission shaft (propeller shaft) according to the present invention can also be applied to a propeller shaft having a multi-piece structure, for example, having a plurality of tubes connected by couplings.

[0018] The tube 1 is made of carbon fiber reinforced plastic (CFRP) and is cylindrical with a constant inner diameter R1 in the axial direction. The wall thicknesses T1 and T2 of the first end 11 and 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 plastic (CFRP) in the radial direction, and is formed of at least two layers, an inner layer 13 and an outer layer 14.

[0019] 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. Furthermore, when the tube 1 is formed from a fiber reinforced resin, it may be formed from, for example, glass fiber reinforced resin (FRP) in addition to the carbon fiber reinforced resin (CFRP) according to this embodiment.

[0020] 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. 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.

[0021] 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. 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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, 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, the first serration portion 26 engages the first insertion portion 22 and the tube 1 so that they can rotate together. As a result, the first insertion portion 22 is fixedly supported by the inner circumferential portion 111 of the first end 11 of the tube 1 via the first serration portion 26.

[0026] A first collision load F1 is set between the first serration portion 26 and the tube 1, 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. In this embodiment, the first collision load F1 is set based on a first bite length L1, which is the bite length (tooth width) of the first serration portion 26 that engages with the inner periphery 111 of the first end 11 of the tube 1.

[0027] 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.

[0028] 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 screwed into the first joint portion 4 from the tube 1 side and fastened to the first power transmission device comes into contact with the end face (first end face 112) on the first end portion 11 side of the tube 1.

[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 so as to be rotatable together with the outer ring member 42 via a plurality of bolts 6 that axially penetrate the outer ring member 42. Furthermore, an outer ring side axial groove 421, in which 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 and the outer ring member 42 rotate together, and the rotational torque output from the first power transmission device 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] The second serration portion 36 is formed with grooves 361 recessed radially inward and extending in a direction parallel to the rotation axis Z, and the outer diameter D2 of the tooth tips 362 is set slightly larger than the inner diameter R1 of the tube 1. That is, 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, the second serration portion 36 engages the second insertion portion 32 and the tube 1 so that they can rotate together. As a result, the second insertion portion 32 is fixedly supported by the inner circumferential portion 121 of the second end 12 of the tube 1 via the second serration portion 36. In this embodiment, the outer diameter D2 of the tooth tips 362 of the second serration portion 36 is set to be the same as the outer diameter D1 of the tooth tips 262 of the first serration portion 26. In other words, the second engagement amount X2 of the second serration portion 36 is set to be the same as the first engagement amount X1 of the first serration portion 26.

[0037] 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 starts to move along the inner periphery of the tube 1 from the second end 12 toward the first end 11. In this embodiment, the second collision load F2 is set based on a second bite length L2, which is the bite length (tooth width) of the second serration portion 36 that engages with the inner periphery 121 of the second end 12 of the tube 1.

[0038] In this embodiment, the second collision load F2 is set to be larger than the first collision load F1. That is, the second bite length L2 of the second serration portion 36 is formed to be longer than the first bite length L1 of the first serration portion 26. In other words, the first insertion portion 22 at the first end 11 of the tube 1 starts to move from the first end 11 toward the second end 12 before the second insertion portion 32 at the second end 12 of the tube 1 starts to move from the second end 12 toward the first end 11. More specifically, the second bite length L2 is set to be approximately twice the first bite length L1.

[0039] The second joint portion 5 is configured by a so-called rubber joint, 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.

[0040] 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 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.

[0041] The second joint portion 5 has an outer diameter D4 that is larger than the 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 surface 351 of the second joint-side connecting portion 35 is configured to be able to abut against the end surface (second end surface 122) of the tube 1 on the second end 12 side.

[0042] Figure 3 is an enlarged cross-sectional view of a main portion of the propeller shaft PS1, showing an enlarged view of a main portion of a cross section taken along line A-A in Figure 2. Figure 4 shows a modified example of the first serration portion 26 shown in Figure 3. Note that in this embodiment, the first serration portion 26 and the second serration portion 36 differ only in the tooth width corresponding to the bite length L1, and the height H of the tooth tip 262 is the same. Therefore, for convenience, the following description will be given using the first serration portion 26 as an example, and a detailed description of the second serration portion 36 will be omitted.

[0043] 3 , the first serration portion 26 is formed so that the tooth tips 262 are sharply pointed. As a result, when the first insertion portion 22 is press-fitted into the first end 11 of the tube 1, the sharply pointed tooth tips 262 scrape the inner periphery 111 of the first end 11 of the tube 1 along the axial direction, thereby inserting the first insertion portion 22 into the inner periphery 111 of the first end 11 of the tube 1.

[0044] Furthermore, the first serration portion 26 is not limited to the sharp tooth tips 262 shown in Fig. 3 , and may be formed in a rounded arc shape as shown in Fig. 4 . In this case, it is desirable that the tooth tips 262 of the first serration portion 26 be formed with a radius Rx that is smaller than the radius Rv connecting a pair of tooth surfaces 263 of the first serration portion 26. By setting the radius Rx of the tooth tips 262 to be relatively small in this way, the surface pressure of the tooth tips 262 when the first insertion portion 22 is press-fitted into the tube 1 is increased, and good engagement of the tooth tips 262 with the inner peripheral portion 111 of the tube 1 can be ensured.

[0045] (Collapse structure of propeller shaft) Figure 5 is a semi-longitudinal cross-sectional view showing the state before and after collapse occurs in the propeller shaft PS1 shown in Figure 2, where (a) shows a state where no collapse occurs, (b) shows a state where collapse occurs on the first end 11 side of the tube 1, and (c) shows a state where collapse occurs on the second end 12 side of the tube 1.

[0046] In the following, "collapse" refers to the state in which the first insertion portion 22 and the second insertion portion 32 are released (destroyed) from their fixed state relative to the tube 1 when an axial load Fx is input to the propeller shaft PS1, causing the first shaft portion 2 (first connection base 21) and the second shaft portion 3 (second connection base 31) to sink into the interior of the tube 1.

[0047] For example, a case will be described in which a vehicle is hit from the front and a compressive axial load Fx greater than the second collision load F2 acts on the front end of the propeller shaft PS1. This axial load Fx is transmitted from the first power transmission device (not shown) to the first shaft portion 2 via the first joint portion 4.

[0048] Then, because the propeller shaft PS1 according to this embodiment has the first collision load F1 set relatively small compared to the second collision load F2, collapse occurs first at the first end 11 of the tube 1 from the normal state shown in Fig. 5(a). That is, between the first shaft portion 2 and the tube 1, which is subjected to an axial load Fx greater than the first collision load F1, the fixed state between the first insertion portion 22 and the tube 1 is released (destroyed), and the first connection base portion 21 slides into the first end 11 of the tube 1, as shown in Fig. 5(b). Specifically, at the first end 11 of the tube 1, the first insertion portion 22 moves from the first end 11 toward the second end 12 until the heads 60 of the bolts 6 of the first joint portion 4 abut against the first end face 112 of the tube 1.

[0049] Next, in the propeller shaft PS1, an axial load Fx is transmitted from the first shaft portion 2 to the second shaft portion 3 via the tube 1. The axial load Fx acts on the second shaft portion 3, which is sandwiched between the first shaft portion 2 and the second power transmission device (not shown), due to a reaction force. Then, a collapse occurs on the second end 12 side of the tube 1 with a delay from the collapse on the first end 11 side. That is, between the second shaft portion 3 that receives the axial load Fx greater than the second collision load F2 and the tube 1, the fixed state between the second insertion portion 32 and the tube 1 is released (destroyed), as shown in FIG. 5C , 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 connecting portion 35 abuts against the second end surface 122 of the tube 1.

[0050] As described above, in this embodiment, the collapse state is controlled based on the magnitude relationship between the first collision load F1 and the second collision load F2 when the axial load Fx is applied, so that the first end 11 side of the tube 1 collapses first, followed by the second end 12 side of the tube 1. The collapse that occurs on the first end 11 side and the second end 12 side of the tube 1 buffers the axial load Fx and absorbs the collision energy of the vehicle. In other words, the first connection base 21 and the second connection base 31 normally slide 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.

[0051] (Effects of the Present Embodiment) In the conventional propeller shaft, the first and second insertion portions, each having the same first and second serration shapes, are press-fit into the first and second ends of the FRP cylindrical body. Therefore, during a vehicle collision, depending on processing errors in the FRP cylindrical body and the first and second insertion portions, it was difficult to predict which of the first and second ends of the FRP cylindrical body would break first, i.e., which of the first and second insertion portions would penetrate into the FRP cylindrical body first. This left room for improvement in the fact that the crash performance of the propeller shaft PS1 was unstable.

[0052] 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.

[0053] The propeller shaft PS1 is a power transmission shaft (propeller shaft) that transmits power between a first power transmission device (not shown) and a second power transmission device (not shown) of a vehicle, and includes a tube 1 formed in a cylindrical shape, a first joint member having a first main body portion (a first connection base portion 21 and a first joint portion 4) and a first insertion portion 22, the first insertion portion 22 being supported in a fixed state by an inner circumferential portion 111 of a first end portion 11 and a second end portion 12 that are a pair of ends of the tube 1 in the direction of the rotation axis Z, and a first collision load F1 is set between the first insertion portion 22 and the tube 1, at which the fixed state with the tube 1 is released and the first insertion portion 22 starts to move from the first end portion 11 toward the second end portion 12 of the tube 1, and the first main body portion (the first connection base portion 21 and the first joint portion 4) is positioned closer to the first end portion 11 than the first end portion 11 in the direction of the rotation axis Z. and a second coupling member J2 having a second main body portion (a second connection base portion 31 and a second joint portion 5) and a second insertion portion 32, wherein 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 a second collision load F2 is set between the second insertion portion 32 and the tube 1, at which the fixed state between the second insertion portion 32 and the tube 1 is released and the second insertion portion 32 starts to move from the second end 12 toward the first end 11 of the tube 1, and the second collision load F2 is set to be larger than the first collision load F1. The second main body portion (the second connection base portion 31 and the second joint portion 5) is located on the opposite side of the second insertion portion 32 from the second end 12 in the direction of the rotation axis Z, and the second coupling member J2 is connected to the second power transmission device (not shown).

[0054] As described above, in this embodiment, the second insertion portion 32 is configured to be released from the fixed state between the tube 1 when a second collision load F2 acts that is greater than the first collision load F1 that releases the fixed state between the first insertion portion 22 and the tube 1. Therefore, during a vehicle collision, i.e., when an axial load Fx acts on the propeller shaft PS1, the fixed state of the first insertion portion 22 is released before the second insertion portion 32, making it possible to control the order in which the first insertion portion 22 and the second insertion portion 32 are released from the tube 1. This improves the stability of the collision performance of the propeller shaft PS1.

[0055] In this embodiment, the tube 1 is made of a material formed by solidifying fibers with resin.

[0056] In this way, in this embodiment, the tube 1 is made of a 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.

[0057] In particular, in this embodiment, the tube 1 is made of carbon fiber reinforced plastic (CFRP).

[0058] 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.

[0059] 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).

[0060] In addition, in this embodiment, the first insertion portion 22 has a first serration portion 26 on its outer periphery that bites into the inner circumferential surface of the first end 11 of the tube 1, and the first collision load F1 is set by a first bite length L1, in the direction of the rotation axis Z, by which the first serration portion 26 bites into the inner circumferential surface of the first end 11 of the tube 1; the second insertion portion 32 has a second serration portion 36 on its outer periphery that bites into the inner circumferential surface of the second end 12 of the tube 1; and the second collision load F2 is set by a second bite length L2, in the direction of the rotation axis Z, by which the second serration portion 36 bites into the inner circumferential surface of the second end 12 of the tube 1; the second bite length L2 is set longer than the first bite length L1.

[0061] In this manner, in the present embodiment, the second bite length L2 is set to be longer than the first bite length L1, and therefore the second collision load F2 is set to be larger than the first collision load F1. Therefore, compared to a case in which the bite amount of the second insertion portion 32 in the tube 1 (second bite amount X2, which will be described later) is set to be larger than the bite amount of the first insertion portion 22 in the tube 1 (first bite amount X1, which will be described later) and therefore the second collision load F2 is set to be larger than the first collision load F1, as in a second embodiment of the present invention, which will be described later, the strength of the tube 1 can be ensured and the collision load of the propeller shaft PS1 can be easily controlled.

[0062] That is, when the first collision load F1 and the second collision load F2 are controlled based on the engagement between the first and second insertion portions 22 and 32, increasing the engagement between the first and second insertion portions 22 and 32 increases the outer diameters of the first and second insertion portions 22 and 32. As a result, the first and second insertion portions 22 and 32 significantly expand the first and second ends 11 and 12 of the tube 1, potentially reducing the strength of the tube 1. In contrast, when the first collision load F1 and the second collision load F2 are controlled based on the first engagement length L1 and the second engagement length L2, as in the present embodiment, the outer diameters of the first and second insertion portions 22 and 32 are not changed. This eliminates the risk of reducing the strength of the tube 1. Furthermore, by not changing the outer diameters of the first and second insertion portions 22 and 32, there is no need to reconsider the strength design of the tube 1. This has the advantage that the first collision load F1 and the second collision load F2 can be controlled relatively easily compared to when the first collision load F1 and the second collision load F2 are controlled based on the engagement between the first insertion portion 22 and the second insertion portion 32 described above.

[0063] In addition, in this embodiment, the first insertion portion 22 has a first serration portion 26 on the outer periphery of the first insertion portion 22 that bites into the inner periphery of the first end 11 of the tube 1, and the second insertion portion 32 has a second serration portion 36 on the outer periphery of the second insertion portion 32 that bites into the inner periphery of the second end 12 of the tube 1, and at least one of the tip ends of the first serration portion 26 and the second serration portion 36 is formed into a sharp shape when viewed in a cross section perpendicular to the rotation axis Z.

[0064] In this manner, in the present embodiment, the tip end portion of at least one of the first serration portion 26 and the second serration portion 36 is formed into a sharp shape when viewed in a cross section perpendicular to the rotation axis Z of the tube 1. By forming the tip end portion of at least one of the first serration portion 26 and the second serration portion 36 into a sharp shape in this manner, the first serration portion 26 or the second serration portion 36 can be more easily engaged with the tube 1, improving the workability in manufacturing the propeller shaft PS1 and enabling the productivity of the propeller shaft PS1 to be improved.

[0065] As a modified example of this embodiment, as shown in FIG. 4, the first insertion portion 22 may have a first serration portion 26 on the outer periphery of the first insertion portion 22 that engages with the inner periphery of the first end 11 of the tube 1, and the second insertion portion 32 may have a second serration portion 36 on the outer periphery of the second insertion portion 32 that engages with the inner periphery of the second end 12 of the tube 1, and at least one of the tip ends of the first serration portion 26 and the second serration portion 36 may be formed in an arc shape when viewed in a cross section perpendicular to the rotation axis Z.

[0066] In this modified example, the tip portions of the first serration portion 26 to the second serration portion 36 are rounded, which makes it possible to suppress the generation of burrs when machining the first serration portion 26 to the second serration portion 36. This suppresses an unintended increase in collision load due to the burrs, thereby improving the controllability of the collision load of the propeller shaft PS1.

[0067] In this embodiment, the first power transmission device (not shown) is a transmission TM, and the second power transmission device (not shown) is a differential DF.

[0068] In this manner, in this embodiment, the first collision load F1 on the first end 11 side of the tube 1 connected to the transmission TM, which is mounted relatively farther forward of the vehicle, is set relatively low. Since vehicles typically collide from the front, setting the collision load on the front side of the vehicle relatively low can enhance safety.

[0069] Second Embodiment Figure 6 shows a second embodiment of a power transmission shaft (propeller shaft) according to the present invention, in which the configuration related to the first collision load F1 and the second collision load F2 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 description of this embodiment will refer to the first coupling member J1 side in Figure 6 as the "front" and the second coupling member J2 side as the "rear." The direction along the rotation axis Z in Figure 6 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."

[0070] (Configuration of Propeller Shaft) FIG. 6 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.

[0071] As shown in FIG. 6 , in the propeller shaft PS2 according to this embodiment, the first engagement length L1 of the first insertion portion 22 and the second engagement length L2 of the second insertion portion 32 are set to be the same. At the first end 11 of the tube 1, the first collision load F1 is set based on the first engagement length X1, which is the amount by which the first serration portion 26 engages with the inner periphery 111 of the first end 11 of the tube 1. The second collision load F2 is set based on the second engagement length X2, which is the amount by which the second serration portion 36 engages with the inner periphery 121 of the second end 12 of the tube 1. That is, the second engagement length X2 of the second serration portion 36 is larger than the first engagement length X1 of the first serration portion 26. Specifically, the second engagement length X2 is set to be approximately twice the first engagement length X1.

[0072] (Action and effect of this embodiment) As described above, in the propeller shaft PS2 according to this embodiment, the first insertion portion 22 has, on its outer periphery, the first serration portion 26 that meshes with the inner circumferential surface of the first end 11 of the tube 1, and the first collision load F1 is set by a first meshing amount X1, where the first serration portion 26 meshes with the inner circumferential surface of the first end 11 of the tube 1, in the direction of the rotation axis Z. The second insertion portion 32 has, on its outer periphery, the second serration portion 36 that meshes with the inner circumferential surface of the second end 12 of the tube 1, and the second collision load F2 is set by a second meshing amount X2, where the second serration portion 36 meshes with the inner circumferential surface of the second end 12 of the tube 1, in the direction of the rotation axis Z. The second meshing amount X2 is set to be larger than the first meshing amount X1.

[0073] As described above, in this embodiment, the second interference X2 is set larger than the first interference X1, and therefore the second collision load F2 is set larger than the first collision load F1. As described above, in this embodiment, the collision load is controlled by making the second interference X2 of the second insertion portion 32 relatively larger than the first interference X1 of the first insertion portion 22, thereby enabling the transmission of a relatively large torque. Furthermore, when the collision load is controlled by making the interference X2 of the second insertion portion 32 larger than the interference X1 of the first insertion portion 22, the interference length L2 of the second insertion portion 32 can be set relatively short, thereby enabling the second insertion portion 32 to be shortened, thereby reducing the manufacturing cost of the propeller shaft PS2.

[0074] Third Embodiment Figure 7 shows a third embodiment of a power transmission shaft (propeller shaft) according to the present invention, in which the configuration related to the first collision load F1 and the second collision load F2 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 description thereof will be omitted. For convenience, in describing this embodiment, the first coupling member J1 side in Figure 7 will be referred to as the "front" and the second coupling member J2 side as the "rear." The direction along the rotation axis Z in Figure 7 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."

[0075] (Configuration of Propeller Shaft) FIG. 7 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.

[0076] 7 , in the propeller shaft PS3 according to this embodiment, the first engagement length L1 of the first insertion portion 22 and the second engagement length L2 of the second insertion portion 32 are set to be the same. At the first end 11 of the tube 1, the first serration portion 26 engages with the inner circumferential surface of the first end 11 of the tube 1, thereby fixedly supporting the first insertion portion 22 at the first end 11 of the tube 1. At the second end 12 of the tube 1, the second serration portion 36 engages with the inner circumferential surface of the second end 12 of the tube 1, and the second serration portion 36 and the inner circumferential surface of the second end 12 of the tube 1 are bonded together with adhesive G, thereby fixedly supporting the second insertion portion 32 at the second end 12 of the tube 1. With this configuration, in this embodiment, the first collision load F1 is set based on the first bite length L1 of the first serration portion 26, while the second collision load F2 is set based on the second bite length L2 of the second serration portion 36 and the adhesive strength of the adhesive G. As a result, the second collision load F2 is set to be larger than the first collision load F1.

[0077] (Action and effect of this embodiment) As described above, in the propeller shaft PS3 of this embodiment, the first insertion portion 22 has a first serration portion 26 on the outer periphery of the first insertion portion 22 that engages with the inner circumferential surface of the first end 11 of the tube 1, and the second insertion portion 32 has a second serration portion 36 on the outer periphery of the second insertion portion 32 that engages with the inner circumferential surface of the second end 12 of the tube 1, and the second serration portion 36 and the tube 1 are bonded together with adhesive G.

[0078] In this manner, in this embodiment, by bonding the second serration portion 36 and the tube 1 with the adhesive G, the second collision load F2 is set to be greater than the first collision load F1. In this manner, by controlling the second collision load F2 to be relatively large by applying the adhesive G to the second serration portion 36, precision machining of the first serration portion 26 and the second serration portion 36 is not required. In other words, even if the machining precision of the first serration portion 26 and the second serration portion 36 is relatively low, the adhesive force of the adhesive G can ensure that the second collision load F2 can be withstood. This allows for a reduction in the manufacturing cost of the propeller shaft PS3.

[0079] [Fourth Embodiment] Figure 8 shows a fourth embodiment of a power transmission shaft (propeller shaft) according to the present invention, in which the configuration related to the first collision load F1 and the second collision load F2 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 description thereof will be omitted. For convenience, in describing this embodiment, the first coupling member J1 side in Figure 8 will be referred to as the "front" and the second coupling member J2 side as the "rear." The direction along the rotation axis Z in Figure 8 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."

[0080] (Configuration of Propeller Shaft) FIG. 8 shows the overall configuration of a propeller shaft PS4 according to a fourth embodiment of the present invention, and shows a half cross-sectional view of the propeller shaft PS4 cut along the direction of the rotation axis Z.

[0081] 8 , in the propeller shaft PS4 according to this embodiment, the tube 1 is formed of a metal material. In the propeller shaft PS4, 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.

[0082] That is, a first female spline portion 15 extending along the axial direction is formed on the inner periphery 111 of the first end portion 11 of the tube 1. Similarly, a second female spline portion 16 extending along the axial direction is formed on the inner periphery 121 of the second end portion 12 of the tube 1.

[0083] Furthermore, a first male spline portion 27 is formed on the outer periphery of the first insertion portion 22. The first male spline portion 27 meshes with the first female spline portion 15 of the tube 1 and is axially movable along the first female spline portion 15. 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. Similarly, a second male spline portion 37 is formed on the outer periphery of the second insertion portion 32 of the tube 1. The second male spline portion 37 meshes with the second female spline portion 16 of the tube 1 and is axially movable along the second female spline portion 16. 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.

[0084] The first collision load F1 is set by the first meshing length L1, which is the length of meshing between the first female spline portion 15 and the first male spline portion 27. On the other hand, the second collision load F2 is set by the second meshing length L2, which is the length of meshing between the second female spline portion 16 and the second male spline portion 37. Furthermore, in this embodiment, the second meshing length L2 is set to be longer than the first meshing length L1.

[0085] While the present embodiment illustrates an example in which the first collision load F1 is set by the first meshing length L1 and the second collision load F2 is set by the second meshing length L2, the first collision load F1 may be set by the first meshing margin X1 and the second collision load F2 may be set by the second meshing margin X2, as in the second embodiment. Furthermore, the second female spline portion 16 and the second male spline portion 37 may be bonded together with an adhesive G, as in the third embodiment.

[0086] (Action and effect of this embodiment) As described above, in the propeller shaft PS4 according to this embodiment, the first female spline portion 15 is formed on the inner periphery 111 of the first end 11 of the tube 1, the first male spline portion 27 that meshes with the first female spline portion 15 and is movable in the direction relative to the rotation axis Z is formed on the outer periphery of the first insertion portion 22, the outer periphery of the first insertion portion 22 is press-fitted into the inner periphery 111 of the first end 11 of the tube 1, the second female spline portion 16 is formed on the inner periphery 121 of the second end 12 of the tube 1, the second male spline portion 37 that meshes with the second female spline portion 16 and is movable in the direction relative to the rotation axis Z is formed on the outer periphery of the second insertion portion 32, and the outer periphery of the second insertion portion 32 is press-fitted into the inner periphery 121 of the second end 12 of the tube 1.

[0087] In this manner, in this embodiment, the tube 1 is connected to the first insertion portion 22 and the second insertion portion 32 via splines. Therefore, unlike the first, second, and third embodiments, the tube 1 can be made of an iron-based material. This allows the propeller shaft PS4 to be manufactured at a relatively low cost compared to when the tube 1 is made of fiber-reinforced resin.

[0088] Fifth Embodiment Figure 9 shows a fifth embodiment of a power transmission shaft (propeller shaft) according to the present invention, in which the configuration related to the first collision load F1 and the second collision load F2 in the propeller shaft PS4 according to the fourth embodiment is modified. The basic configuration other than the modified points is the same as that of the fourth embodiment, and therefore the same components as those in the fourth embodiment are denoted by the same reference numerals and description thereof will be omitted. 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."

[0089] (Configuration of Propeller Shaft) Figure 9 shows a half cross-sectional view of a propeller shaft PS5 according to a fifth embodiment of the present invention, cut along the direction of the rotation axis Z, in which (a) shows an enlarged view of the vicinity of the first end 11 of the tube 1, and (b) shows an enlarged view of the vicinity of the second end 12 of the tube 1.

[0090] 9A, in the propeller shaft PS5 according to this embodiment, first pin through holes 17, each having a generally cylindrical shape and allowing a first pin P1 to pass therethrough, are formed radially in the first end 11 of the tube 1. Meanwhile, a first pin insertion hole 28, through which the first pin P1 can be inserted, is formed in the first insertion portion 22 at a position radially opposite the first pin through hole 17. The first pin P1 is press-fitted from the first pin through hole 17 side so as to straddle the first pin through hole 17 and the first pin insertion hole 28, thereby fixedly supporting the first insertion portion 22 at the first end 11 of the tube 1. In this embodiment, the first collision load F1 is set based on the strength at which the first pin P1 breaks.

[0091] A first seal member S1 is disposed at the open end of the first end 11 of the tube 1, between the inner periphery 111 of the first end 11 and the outer periphery of the first insertion portion 22 of the first shaft portion 2, and at a position outside the first pin P1. The first seal member S1 liquid-tightly seals a first gap formed between the inner periphery 111 of the first end 11 and the outer periphery of the first insertion portion 22 of the first shaft portion 2 at the first end 11 of the tube 1, and prevents moisture and foreign matter from entering through the first gap.

[0092] Furthermore, a first cover member C1 having a generally circular shape with an L-shaped cross section is fixed by crimping to the outer peripheral edge of the first end 11 of the tube 1. The first cover member C1 has a first outer peripheral portion C11 that covers the outer peripheral side of the tube 1 and faces the first pin P1 in the radial direction, thereby preventing the first pin P1 from falling off. At the same time, the first cover member C1 has a first axial end face C12 that covers the first end face 112 of the tube 1 and faces the first seal member S1 in the axial direction, thereby preventing the first seal member S1 from falling off.

[0093] Similarly, in the propeller shaft PS5 according to this embodiment, as shown in FIG. 9B , second pin through holes 18, each having a generally cylindrical shape and allowing the second pin P2 to pass therethrough, are formed radially in the second end 12 of the tube 1. Meanwhile, second pin insertion holes 38, each allowing the second pin P2 to be inserted therethrough, are formed radially opposite the second pin through holes 18 in the second insertion portion 32. The second pin P2 is press-fitted from the second pin through hole 18 side so as to straddle the second pin through hole 18 and the second pin insertion hole 38, thereby fixedly supporting the second insertion portion 32 at the second end 12 of the tube 1. Note that in this embodiment, the second collision load F2 is set based on the strength at which the second pin P2 breaks. In other words, for example, the outer diameter of the second pin P2 is set relatively larger than the outer diameter of the first pin P1, so that the breaking strength of the second pin P2 is set larger than the breaking strength of the first pin P1, and the second collision load F2 is set larger than the first collision load F1.

[0094] A second seal member S2 is disposed at the open end of the second end 12 of the tube 1, between the inner periphery 121 of the second end 12 and the outer periphery of the second insertion portion 32 of the second shaft portion 3, and at a position outside the second pin P2. The second seal member S2 liquid-tightly seals a second gap formed at the second end 12 of the tube 1 between the inner periphery 121 of the second end 12 and the outer periphery of the second insertion portion 32 of the second shaft portion 3, and prevents moisture and foreign matter from entering through the second gap.

[0095] Furthermore, a second cover member C2 having a generally circular shape and an L-shaped cross section is fixed by crimping to the outer peripheral edge of the second end 12 of the tube 1. The second cover member C2 has a second outer peripheral portion C21 that covers the outer peripheral side of the tube 1 and faces the second pin P2 in the radial direction, thereby preventing the second pin P2 from falling off. At the same time, the second cover member C2 has a second axial end face C22 that covers the second end face 122 of the tube 1 and faces the second seal member S2 in the axial direction, thereby preventing the second seal member S2 from falling off.

[0096] (Action and effect of this embodiment) As described above, in the propeller shaft PS5 according to this embodiment, first pin holes (first pin through hole 17 and first pin insertion hole 28) are formed in the first end 11 of the tube 1 and the first insertion portion 22, into which the first pin P1 can be inserted so as to straddle the first end 11 of the tube 1 and the first insertion portion 22 in the radial direction, and second pin holes (second pin through hole 18 and second pin insertion hole 38) are formed in the second end 12 of the tube 1 and the second insertion portion 32, into which the second pin P2 can be inserted so as to straddle the second end 12 of the tube 1 and the second insertion portion 32 in the radial direction, and the breaking strength of the second pin P2 is greater than the breaking strength of the first pin P1.

[0097] As described above, in this embodiment, the tube 1 is coupled to the first insertion portion 22 and the second insertion portion 32 via the first pin P1 and the second pin P2, respectively. Therefore, with the exception of the first pin P1 and the second pin P2, which are used to set the first collision load F1 and the second collision load F2, components of a conventional propeller shaft in which the first coupling member J1 and the second coupling member J2 are spline-coupled to both ends of the tube 1 can be shared. This reduces the manufacturing cost of the propeller shaft PS5. Furthermore, because the collision load is controlled solely by the coupling means of the first pin P1 and the second pin P2, this has the advantage of making collision load control relatively easy compared to other coupling means, such as the serrations in the first embodiment.

[0098] 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.

[0099] For example, in each of the above embodiments, the first power transmission device (not shown) is a transmission TM mounted on a vehicle, and the second power transmission device (not shown) is a differential DF mounted on a vehicle. However, as shown in Fig. 10, the reverse configuration may also be used. Specifically, the present invention may also 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 (not shown) may be a differential DF, and the second power transmission device may be the transmission TM.

[0100] According to this modification, the first collision load F1 on the first end 11 side of the tube 1 connected to the differential DF mounted relatively rearward of the vehicle is set relatively low. In this way, by setting the collision load on the rear side of the vehicle relatively low, there is an advantage in that safety in the event of a rear-end collision of the vehicle can be improved.

[0101] 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 (not shown) may be used as a drive source such as an engine, and the second power transmission device (not shown) may be used as the transmission TM, or vice versa.

[0102] 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 (not shown).

[0103] Furthermore, in the present invention, controlling the first collision load F1 and the second collision load F2 by the first bite length L1 and the second bite length L2, the first bite margin X1 and the second bite margin X2, the adhesive G, and the pin P, as in the above-described embodiments, is particularly effective in cases where no flange portion is formed at the end of the first insertion portion 22 on the first connection base 21 side and the end of the second insertion portion 32 on the second connection base 31 side. In other words, in an aspect in which flange portions are formed at the end of the first insertion portion 22 on the first connection base 21 side and the end of the second insertion portion 32 on the second connection base 31 side, the first collision load F1 and the second collision load F2 may be controlled by the outer diameter of each flange portion, etc.

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 fixed by a first serration portion provided on an outer periphery of the first insertion portion being engaged with an inner periphery of the first end by a first engagement length, the first serration portion being one of a pair of ends in a direction of a rotation axis of the tube, and a first collision load at which the first insertion portion starts to move from the first end to the second end of the tube when the fixed state with the tube is released is set by the first engagement length, the first main body portion is provided on an 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; The first joint member; A second joint member having a second body portion and a second insertion portion, the second insertion portion is fixed by a second serration portion provided on an outer periphery of the second insertion portion being engaged with an inner periphery of the second end of the tube by a second engagement length, and a second collision load at which the second insertion portion starts to move from the second end of the tube toward the first end of the tube when the fixed state with the tube is released is set by the second engagement length between the second insertion portion and the tube, and the second collision load is set to be larger than the first collision load, 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. The second joint member; A power transmission shaft comprising:

2. 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:

3. 3. The power transmission shaft according to claim 2, The second serration portion and the tube are bonded together with an adhesive. A power transmission shaft characterized by:

4. 3. The power transmission shaft according to claim 2, At least one of a tip end of the first serration portion and a tip end of the second serration portion is formed into a sharp shape when viewed in a cross section perpendicular to the rotation axis. A power transmission shaft characterized by:

5. 3. The power transmission shaft according to claim 2, At least one of the first serration portion and the second serration portion has a tip end formed in an arc shape when viewed in a cross section perpendicular to the rotation axis. A power transmission shaft characterized by:

6. 3. The power transmission shaft according to claim 2, The fibers are carbon fibers. A power transmission shaft characterized by:

7. 3. The power transmission shaft according to claim 2, The fibers are glass fibers. A power transmission shaft characterized by:

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

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