DESC:[0001] Present invention, in general, relates to the field of automobiles. Particularly, but not exclusively, the present invention relates to a propeller shaft of a power train for a vehicle.

BACKGROUND OF THE INVENTION

[0002] Vehicle propeller shaft, also known as a drive shaft, are configured to transmit torque and rotation from a transmission to its wheels or other mechanical components. In a conventional driveline of an electric vehicle, the propeller shaft is directly connected to an electric motor at one end, and to a rear axle at the other end. When the electric motor drives the vehicle through the driveline, vibratory forces are generated in a crown wheel pinion pair of the rear axle due to torque transfer from the motor. These forces are transferred to the vehicle body through various paths, and the dominant path is through the propeller shaft. Also, at high speed, the propeller shaft vibrates at resonance frequency due to pairing of the rear axle and the crown wheel pinion and causes vibrations. These vibrations are also transferred to a body of the vehicle resulting in noise with high-amplitude inside the vehicle cabin. Moreover, while the vehicle is running, noise with high-amplitudes are in the electric vehicles such as an electric bus (EV Bus) during accelerating and decelerating, which causes discomfort to the passengers. Further, prolonged operation of the propeller shaft in a resonance zone i.e., at resonance frequency, may result in decline in performance of the propeller shaft and in turn the transmission. In some instances, such operation in the resonance zone may result in failure of the propeller shaft, which is not desirable.

[0003] The present disclosure is directed to overcome one or more limitations stated above or any other limitations associated with the conventional mechanisms.

[0004] The drawbacks/difficulties/disadvantages/limitations of the conventional techniques explained in the background section are just for exemplary purpose and the disclosure would never limit its scope only such limitations. A person skilled in the art would understand that this disclosure and below mentioned description may also solve other problems or overcome the other drawbacks/disadvantages of the conventional arts which are not explicitly captured above.

SUMMARY OF THE INVENTION

[0005] One or more shortcomings of the prior art are overcome by a propeller shaft and a power train as claimed and additional advantages are provided through the propeller shaft and the power train as claimed in the present disclosure. Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.

[0006] In one non-limiting embodiment of the present disclosure a propeller shaft is disclosed. The propeller shaft includes a tubular body defined by a first segment and a second segment. The first segment is connectable to a power unit of the vehicle and the second segment is coupled to the first segment on one end and being connectable to a differential of the vehicle at another end of the second segment. The first segment and the second segment are coupled by a spline joint. The first segment is adapted to decouple from the first segment, during bending action of the propeller shaft, to transmit torque from the power unit to the differential of the vehicle, and the second segment is adapted to balance inertia of the propeller shaft.

[0007] In an embodiment, the first segment is defined with a predefined thickness corresponding to dynamic stiffness of the propeller shaft.

[0008] In an embodiment the predefined thickness of the first segment corresponds to a natural frequency of the propeller shaft configured to decouple the second segment from the first segment during bending action.

[0009] In an embodiment, the propeller shaft is made of stainless steel materials comprising molybdenum.

[0010] In an embodiment, radius of the first segment is greater than radius of the second segment.

[0011] In an embodiment, the radii of the first segment and the second segment correspond to dynamic stiffness of the propeller shaft.

[0012] In an embodiment, the dynamic stiffness of the propeller shaft is in stiffness coefficient range of 30MN/m to 75 MN/m.

[0013] In an embodiment, mass of the second segment is greater than mass of the first segment.

[0014] In an embodiment, a portion of the second segment is defined by a solid section, where mass of the second segment is greater than 65% to 75% of total mass of the propeller shaft.

[0015] In an embodiment, the second segment extends up to a predetermined length from the other end of the propeller shaft.

[0016] In another non-limiting embodiment of the present disclosure, a power train is disclosed. The power train includes a power unit, and a differential mounted on a rear axle of the vehicle and connectable to the power unit. The power train includes a propeller shaft disposed between the power unit and the differential and configured to couple the power unit and the differential. The power train includes a propeller shaft disposed between the power unit and the differential and configured to couple the power unit and the differential. The propeller shaft includes a tubular body defined by a first segment and a second segment. The first segment is connectable to a power unit of the vehicle and the second segment is coupled to the first segment on one end and being connectable to a differential of the vehicle at another end of the second segment. The first segment and the second segment are coupled by a spline joint. The first segment is adapted to decouple from the first segment, during bending action of the propeller shaft, to transmit torque from the power unit to the differential of the vehicle, and the second segment is adapted to balance inertia of the propeller shaft.

[0017] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[0018] The novel features and characteristic of the disclosure are set forth in the appended claims. The disclosure itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures where like reference numerals represent like elements and in which:

[0019] Figure 1 illustrates a perspective view of a power train of a vehicle, in accordance with an embodiment of the present invention.

[0020] Figure. 2 illustrates a side perspective view of a propeller shaft of the power train of Figure. 1, in accordance with an embodiment of the present invention.

[0021] The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the system and method illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAILED DESCRIPTION

[0022] While the embodiments in the disclosure are subject to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the figures and will be described below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the scope of the disclosure.

[0023] The terms “comprises”, “comprising”, or any other variations thereof used in the disclosure, are intended to cover a non-exclusive inclusion, such that a propeller shaft, and a power train that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such system, or assembly, or device. In other words, one or more elements in a system proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or method.

[0024] Embodiments of the present disclosure disclose a propeller shaft. The propeller shaft includes a tubular body defined by a first segment and a second segment. The first segment is connectable to a power unit of the vehicle and the second segment is coupled to the first segment on one end and being connectable to a differential of the vehicle at another end of the second segment. The first segment and the second segment are coupled by a spline joint. The first segment is adapted to decouple from the first segment, during bending action of the propeller shaft, to transmit torque from the power unit to the differential of the vehicle, and the second segment is adapted to balance inertia of the propeller shaft. With such configuration, the proposed propeller shaft generates minimal resonance frequency, thereby reducing noise generation and attenuating transmission of vibratory forces to the vehicle cabin.

[0025] The disclosure is described in the following paragraphs with reference to Figures 1 to 2. In the figures, the same element or elements which have same functions are indicated by the same reference signs. It is to be noted that, the vehicle is not illustrated in the figures for the purpose of simplicity. One skilled in the art would appreciate that the propeller shaft and the power train as disclosed in the present disclosure may be used in any vehicle including but not liming to, passenger vehicles, commercial vehicles, and the like. The propeller shaft and the powertrain of the present disclosure may also be implemented in vehicles having manual transmission or automatic transmission, for suitably maneuvering the vehicle without deviating from the principles of the present disclosure.

[0026] Figure 1 is an exemplary embodiment of the present disclosure which illustrates a perspective view of a power train (100) of a vehicle. The vehicle may include, but not limited to, a passenger vehicle such as a car, or a commercial vehicle such as a bus and the like. The power train (100) includes a power unit (110) including, but not limited to, an internal combustion engine, a traction motor and the like. The power train (100) includes a differential (116) mounted on a rear axle (106) of the vehicle and connectable to the power unit (110). The differential (116) is configured to receive torque from the power unit (110) and transmit the torque to a plurality of wheels of the vehicle by corresponding wheel hubs as can be seen in Figure 1.

[0027] In an embodiment, the power unit (110) is depicted to be a traction motor, where the vehicle is an electric vehicle. The power train (100) includes a propeller shaft (1000), an electric motor (110), and a rear-axle differential (116) mounted to a rear axle (106). The propeller shaft (1000) is drivingly connected to the electric motor (110) through a motor connecting end (112) and to a rear axle (106) through an axle connecting end (114). The propeller shaft (1000) is connected to the electric motor (110) by universal joints defined at the motor connecting end (112) and the axle connecting end (114). The rear axle (106) includes a left and right wheel hub mountings (104, 108) fitted thereto as can be seen in Figure 1. The propeller shaft (1000) is configured to transmit torque from the power unit (110) to the differential (116), where during such transmission of torque, vibrations from the power unit (110) are transmitted to the differential (116) at a first frequency corresponding to the operation of the power unit (110). For example, the first frequency may correspond to a frequency for a traction motor which may overlap with natural frequency of the propeller shaft (1000) i.e., for example in a range of 140 to 160 Hertz (Hz). Such overlap of the first frequency with a natural frequency of the propeller shaft (1000) may damage the propeller shaft (1000) and transmit whine noises to the body of the vehicle causing discomfort to a driver/passenger of the vehicle.

[0028] Referring now to Figure 2 which illustrates a side perspective view of the propeller shaft (1000) of the power train (100) of Figure. 1. The propeller shaft (1000) includes a tubular body (1) defined by a first segment (11) and a second segment (12) being connectable to the first segment (11). The first segment (11) and the second segment (12) are connectable to each other by one of temporary joining such as a snap joint, or by way of permanent joining such as welding, soldering and the like. In the illustrative embodiment, the first segment (11) and the second segment (12) are depicted to be connected by a spline joint (13) to compensate for relative motion of vehicle suspension by varying length of the propeller shaft along the spline joint (13). The spline joint (13) is configured to cause relative movement of the second segment (12) relative to the first segment (11), for example, the second segment being configured to displace toward and away from the axle connecting end (114). The first segment (11) is connectable to the power unit (110) of the vehicle and the second segment (12) is coupled to the first segment (11) on one end and is connectable to a differential (116) of the vehicle at another end (114) of the second segment (12). In the illustrative embodiment, the first segment (11) and the second segment (12) are coupled to the power unit (110) and the differential (116) of the vehicle respectively by universal joints to transmit torque from the power unit (110) to the differential (116) of the vehicle.

[0029] The propeller shaft (1000) is defined with a length (L), where the length (L) includes length of the second segment (12) from the other end (114), length of the first segment (11) from the motor connecting end (112) and length of the spline joint. Here, the length of the second segment (12) from the other end (114) is defined by a predetermined length (X) from the other end (114) of the propeller shaft (1000). The length of the first segment (11) is defined by a second length (Y) from the motor connecting end (112) of the propeller shaft (1000) and length of the spline joint (13) is defined between the predetermined length (X) and the second length (Y) as can be seen in Figure 2, where the spline joint (13) length is defined by a third length (Z) from the other end (114). The first segment (11) is defined with a predefined thickness corresponding to dynamic stiffness of the propeller shaft (1000). In an embodiment, dynamic stiffness of the propeller shaft refers to ratio of the amplitude of the applied excitation load to the amplitude of the dynamic response. The predefined thickness of the first segment (11) corresponds to a natural frequency of the propeller shaft (1000) configured to decouple the second segment (12) from the first segment (11) during bending action of the propeller shaft (1000). The propeller shaft (1000) is configured to decouple the second segment from the first segment where the natural frequency of the propeller shaft differs from the frequency of vibration forces from the power unit i.e., to a second frequency, for example, in a range of 90 to 110 Hertz (Hz). The radius of the first segment (11) is greater than radius of the second segment (12), while the radii of the first segment (11) and the second segment (12) correspond to dynamic stiffness of the propeller shaft (1000). In an embodiment, the dynamic stiffness of the propeller shaft (1000) is in stiffness coefficient range of 30MN/m to 75 MN/m configured to withstand and block, either partially or substantially, transmission of vibrations from the power unit (110) to the differential (116). The dynamic stiffness of the propeller shaft (1000) is configured to withstand and block transmission of vibration partially in a range of 20 to 50% and substantially in a range of 50 % to 90%. The radii of the first segment (11) and the second segment (12) may be varied based on required dynamic stiffness of the propeller shaft (1000). The first segment (11) is defined by at least a hollow portion and is defined by a tubular profile having the predefined thickness, where the hollow portion is defined by the tubular profile with the predefined thickness. The first segment (11) is adapted to decouple from the second segment (12), during bending action of the propeller shaft (1000), to transmit torque from the power unit (110) to the differential (116) of the vehicle. In the illustrative embodiment, the predefined thickness of the first segment (11) corresponds to the natural frequency of the propeller shaft (1000) configured to decouple the first segment (11) from the second segment (12) during bending action to avoid transmission of vibration forces through the propeller shaft (1000)..

[0030] Table 1 illustrates exemplary radii of the propeller shaft corresponding dynamic stiffness in stiffness coefficient range of 30MN/m to 75 MN/m.

TABLE 1:
Min Radius (mm) Max Radius (mm)
Inner radius limit 37 57
Outer radius limit 40 60

[0031] In an embodiment, mass of the second segment (12) is greater than mass of the first segment (11), where a portion of the second segment (12) is defined by a solid section. In the illustrative embodiment, mass of the second segment (12) is greater than 65% to 75% of total mass of the propeller shaft (1000), where the second segment (12) is completely solid corresponding to mass of the propeller shaft (1000) and mass of the first segment (11). Such configuration of the second segment (12) adapts the second segment (12) to balance inertia of the propeller shaft (1000). Such configuration of the first segment (11) and the second segment (12) reduce or eliminate transmission of vibrations from the power unit (110) to the differential (116) through the propeller shaft (1000), where the natural frequency of the propeller shaft (1000) is varied from the first frequency to balance inertia and decouple the first segment (11) from the second segment (12) to avoid transmission of vibration forces through the propeller shaft (1000). In an embodiment, the propeller shaft (1000) is made of metals including but not limited to, stainless steel, cast iron and the like. In the illustrative embodiment, the propeller shaft (1000) is made up of high grades of carbon steels such as molybdenum-containing stainless steels.

[0032] In an embodiment, the propeller shaft (1000) is defined with predefined mass along the length (L) thereof, where mass of the second segment (12) is greater than the mass of the first segment (11). The predefined mass may be varied based on dimensions of the propeller shaft and the dynamic stiffness corresponding to type of powertrain and type of vehicle. Due to the predefined mass, the propeller shaft (1000) includes a predefined outer diameter (D) and a predefined inner diameter (D’). In the illustrative embodiment, the first segment (11) of the propeller shaft (1000) is defined at the predefined distance (Y) from the motor connecting end (112) and is defined with the predefined outer diameter (D). The spline joint (13) of the propeller shaft (1000) is defined at the predefined distance (Z) from the axle mounting end (114) has the predefined inner diameter (D’). This varied diameter along the length (L) of the propeller shaft (1000) is due to the predefined mass in the first segment (11) and the second segment (12) of the propeller shaft (1000). Such configuration of the first segment (11) and the second segment (12), shifts the location of the center of mass (C) of the propeller shaft (1000) towards the axle mounting end (114) and the mass of the second segment (12) is made more than 65 % to 75 % of the propeller shaft (1000). In the illustrative embodiment, the mass of the second segment (12) is made more than 70% of the total propeller shaft (1000) mass, thereby resulting in predefined mass along the propeller shaft (1000). With such structural configuration including the center of mass (C) being displaced toward the axle mounting end (114) and the greater mass of the second segment (12) disposed towards the axle mounting end (114), a higher inertia is generated, therefore, results in substantial reduction of resonance frequency amplitude of the force generated by the power unit (110) and transmitted along the propeller shaft (1000) and hence the vibratory forces are attenuated before transmission to the vehicle cabin. Furthermore, the predefined thickness of the first segment (11) decouples the first segment (11) from the second segment (12) by shifting the natural frequency of the propeller shaft (1000) from the first frequency due to the predefined thickness corresponding to stiffness coefficient of the propeller shaft (1000).

[0033] Again referring to Figure 2, in an illustrated embodiment, the center of mass (C) of the propeller shaft (1000) is displaced towards the axle mounting end (114), such that the center of mass (C) is located in the predefined section (118) defined from the axle mounting end (114) upto a predetermined length (X) of the propeller shaft (1000). The propeller shaft (1000) includes a predefined mass in the range of 20 kg to 36 kg. Further, mass of the second segment (12) of the propeller shaft (1000) is more than 70% of a total propeller shaft (1000) mass.

[0034] In an embodiment, the propeller shaft (1000) made of high grade carbon steels, having the predefined mass along the length (L) thereof and further defined with predefined dynamic stiffness in the stiffness coefficient range of 30MN/m to 75 MN/m contributes in achieving modal decoupling of the propeller shaft (1000) and thereby resulting in enhanced stiffness of the propeller shaft (1000). Such configuration of the propeller shaft (1000) may reduce or prevent any damage thereof under resonance frequency of the vibrations generated from the power unit (110).

[0035] In an embodiment, the propeller shaft (1000) reduces noise generation and attenuates transmission of vibratory forces from the power unit (110) to the vehicle cabin through the propeller shaft (1000).

[0036] In an embodiment, the propeller shaft (1000) of the present disclosure is defined with enhanced stiffness achieved through dual-tuning (i.e., by inertia balancing at the second segment (12) and mode decoupling at the first segment (11)) of the propeller shaft (1000) by providing predefined mass along the length thereof and further optimizing a dynamic stiffness in a range of 30MN/m to 75 MN/m such that vibration mode configuration of the propeller shaft (1000) is optimized, and modal decoupling is achieved and thus the resonance frequency amplitude at the axle mounting end (114) is reduced significantly.

[0037] In an embodiment, the propeller shaft (1000) of the present disclosure facilitates enhanced stiffness, and includes a predefined mass along the length thereof such that the resonance force transmitted along the propeller shaft (1000) produces substantially reduced amplitude of vibrations, thereby reducing whine noise generation in the cabin.

[0038] In an embodiment, the propeller shaft (1000) of the present disclosure having a predefined mass along the length thereof in which the center of the mass is located towards the axle mounting end (114) of the propeller shaft (1000) such that a higher inertia near the axle mounting end (114) is configured to reduce the angular acceleration, thereby reducing transmission of vibratory forces to the vehicle cabin.

[0039] Advantageously, the disclosed propeller shaft (1000) is configured by optimizing the position of the center of mass and enhancing the stiffness thereof to substantially reduce the transmission of whine noise in a range of 10 decibels (dB) and transmission of vibrations from the power unit (110) to the vehicle cabin, thereby facilitating enhanced comfort to the vehicle driver.

EQUIVALENTS

With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.

It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.”

In addition, where features or aspects of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group.

While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

Referral numerals:
Component Reference numeral
Propeller shaft 1000
Body 1
First segment 11
Second segment 12
Spline joint 13
Power train 100
Power unit 110
First end 112
Second end 114
Differential 116 ,CLAIMS:1. A propeller shaft (1000) for a vehicle, the propeller shaft (1000) comprising:
a tubular body (1) defined by a first segment (11) and a second segment (12), the first segment (11) connectable to a power unit (110) of the vehicle, and
the second segment (12) coupled to the first segment (11) on one end and being connectable to a differential (116) of the vehicle at another end (114) of the second segment, wherein the first segment (11) and the second segment (12) are coupled by a spline joint (13); and
wherein the first segment (11) is adapted to decouple from the second segment (12), during bending action of the propeller shaft (1000), to transmit torque from the power unit (110) to the differential of the vehicle, and the second segment (12) is adapted to balance inertia of the propeller shaft (1000).

2. The propeller shaft (1000) as claimed in claim 1, wherein the first segment (11) is defined with a predefined thickness corresponding to dynamic stiffness of the propeller shaft (1000).

3. The propeller shaft (1000) as claimed in claim 1, wherein the predefined thickness of the first segment corresponds to a natural frequency of the propeller shaft configured to decouple the second segment from the first segment during bending action.

4. The propeller shaft (1000) as claimed in claim 1, wherein the propeller shaft (1000) is made of stainless steel materials comprising molybdenum.

5. The propeller shaft (1000) as claimed in claim 1, wherein radius of the first segment (11) is greater than radius of the second segment (12).

6. The propeller shaft (1000) as claimed in claim 2, wherein the radii of the first segment (11) and the second segment (12) correspond to dynamic stiffness of the propeller shaft (1000).

7. The propeller shaft (1000) as claimed in claim 6, wherein the dynamic stiffness of the propeller shaft (1000) is in stiffness coefficient range of 30MN/m to 75 MN/m.

8. The propeller shaft (1000) as claimed in claim 1, wherein mass of the second segment (12) is greater than mass of the first segment (11).

9. The propeller shaft (1000) as claimed in claim 8, wherein a portion of the second segment (12) is defined by a solid section, where mass of the second segment (12) is greater than 65% to 75% of total mass of the propeller shaft (1000).

10. The propeller shaft (1000) as claimed in claim 1, wherein the second segment (12) extends up to a predetermined length (X) from the other end (114) of the propeller shaft (1000).

11. A power train (100) for a vehicle, the power train (100) comprising:
a power unit (110);
a differential (116) mounted on a rear axle of the vehicle and connectable to the power unit (110); and
a propeller shaft (1000) disposed between the power unit (110) and the differential (116) and configured to couple the power unit (110) and the differential (116), the propeller shaft (1000) comprising:
a tubular body (1) defined by a first segment (11) and a second segment (12), the first segment (11) connectable to a power unit (110) of the vehicle, and
the second segment (12) coupled to the first segment (11) on one end and being connectable to a differential (116) of the vehicle on an other end (114), wherein the first segment (11) and the second segment (12) are coupled by a spline joint (13); and
wherein the first segment (11) is adapted to decouple from the second segment (12), during bending action of the propeller shaft (1000), to transmit torque from the power unit (110) to the differential of the vehicle, and the second segment (12) is adapted to balance inertia of the propeller shaft (1000).