[0001] The present subject matter relates, in general, to automotive
technology and, particularly but not exclusively, to a propeller shaft assembly of a vehicle.
BACKGROUND
[0002] A propeller shaft, also referred to as a drive shaft, is a mechanical
component that is employed in vehicles as part of a drive train for transmitting a drive, and thereby, torque and rotation from a driving member to driven members. For example, the driving member can be an internal combustion engine or a motor, whereas the driven members can be axles or wheels of the vehicle.
[0003] The propeller shaft is usually employed to connect components in
the drive train that cannot be connected directly to the driving member, for instance, because of distance, to transmit the drive without any change in the speed or torque of the drive, or to accommodate variations in alignment and distance between components at two ends of the propeller shaft. In order to accommodate the alignment and/or distance variations between the two ends of the propeller shaft, for instance, due to movement of the vehicle over uneven surfaces, propeller shafts are frequently provided with free degrees of freedom at both ends. This can be achieved using various mechanical joints, such as yoke joints, universal joints, jaw couplings, rag joints, splined joints, or prismatic joints.

[0004] The detailed description is provided with reference to the
accompanying figures. It should be noted that the description and the figures are merely examples of the present subject matter, and are not meant to represent the subject matter itself.
[0005] Figure 1A illustrates a vehicle having a propeller shaft assembly, in
accordance with an example of the present subject matter.
[0006] Figure 1B illustrates the propeller shaft assembly of the vehicle, in
accordance with an example of the present subject matter.
[0007] Figure 2 illustrates an exploded perspective view of the propeller
shaft assembly, in accordance with an example of the present subject matter.
[0008] Figure 3A illustrates a cross-sectional view of the propeller shaft
assembly in a bump motion of the vehicle, in accordance with an example of the present subject matter.
[0009] Figure 3B illustrates a cross-sectional view of the propeller shaft
assembly in a rebound motion of the vehicle, in accordance with an example of the present subject matter.
[0010] Figure 4 illustrates a graph showing forces acting propeller shaft
assembly for bump motion and rebound motion of the vehicle, in accordance with an example of the present subject matter.
[0011] Throughout the drawings, identical reference numbers designate
similar, but not necessarily identical, elements. The figures are not necessarily to scale, and the size of some parts may be exaggerated to more clearly illustrate the example shown. Moreover, the drawings provide examples and/or implementations consistent with the description; however, the

description is not limited to the examples and/or implementations provided in the drawings.
DETAILEDDESCRIPTION
[0012] The present subject matter relates to aspects of a propeller shaft
assembly for a vehicle.
[0013] Generally, a propeller shaft assembly of a vehicle has to operate at
varied distances and varied angles. This is so because one end of a propeller shaft of the propeller shaft assembly is connected to a driving member, such as an engine, which is generally rigidly mounted, and the other end of the propeller shaft is connected to a movable driven member, such as an axle, which changes relative position as the vehicle experiences jerks and bumps while moving on the road.
[0014] In order to accommodate the variations in effective distance
between two connected components, conventional propeller shaft assemblies, generally, use a telescopic propeller shaft which has multiple segments telescopically arranged with respect to each other. However, such propeller shafts may be constructionally complex, making them complex as well as costly for construction. Accordingly, certain other conventional propeller shaft assemblies make use of sliding yoke joints or sliding universal joints along with sliding joint at ends of the propeller shaft to accommodate, both, the variation in distance as well as the variation in angle. For example, the sliding joint at each end of the propeller shaft is capable of sliding in a muffcup.
[0015] Further, the arrangement of the propeller shaft in the muffcup is
supplemented by design of a length of the propeller shaft to accommodate the variations in distance during the movement of the vehicle. In a neutral position, i.e., when the vehicle is on a substantially level surface, the sliding

joints may be positioned in a mid-depth of the muffcup. In a bump motion of the vehicle, the two muffcups may come closer to each other than in the neutral position, leading the ends of the propeller shafts to move deeper into the muff cups. As a result, end walls of one or both the muffcups may interfere with the respective end of the propeller shaft causing noise and also leading to huge amount of wear and tear of the interfering components. In order to overcome this issue, rubber buffers are employed, which, however, adversely affects the depth to which the ends of the propeller shaft can move into the muffcup. This may, in turn, adversely affect the variation in effective distance between ends of propeller shaft that can be accommodated in the bump motion. In case of a rebound motion, the two muffcups can move farther from each other than in the neutral position. If there is adequate amount of force in the motion, such a rebound motion may cause the propeller shaft to break the muffcup and disengage from the drive train.
[0016] To address the abovementioned problems, present subject matter
discloses a propeller shaft assembly for a vehicle. The propeller shaft assembly is part of the drive train of the vehicle and can include a propeller shaft having universal joints at both ends for allowing angular variations during motion of the vehicle. At each universal joint, a slider assembly is provided. The slider assemblies are each disposed in a muffcup. Accordingly, the propeller shaft assembly includes two muffcups, each having one slider assembly positioned therein. As will be understood, the muffcups also form part of a drive train. For example, one of the muffcups can be coupled to a crankshaft of an engine or motor of the vehicle or to an output shaft of a gearbox, whereas the other can be coupled to a wheel shaft or axle or a differential. The slider assemblies are slidably disposed in the respective muffcup to accommodate variations in effective distance between the muffcups.

[0017] In the broadest form, the present subject matter includes at least
one cushioning member disposed in either one or both the muffcups. The cushioning member is positioned between and is coupled to an end of the propeller shaft and an end wall of the muffcup in which the cushioning member is disposed. The cushioning member can have a first end coupled to the end of the propeller shaft and a second end coupled to the end wall of the muffcup, and the cushioning member is adapted to be compressed to an extent that the first end of the cushioning member reaches the second end upon full compression. For example, the cushioning member is adapted to be compressed to the extent that the first end abuts the second end when the cushioning member is completely compressed.
[0018] According to an aspect, the propeller shaft assembly includes a
conical spring as the cushioning member, disposed in each muffcup, in a way that the conical spring is positioned between an end wall of the muffcup and an end of the propeller shaft that is placed in that muffcup. At one end, the conical spring can be coupled to the end wall of the muffcup and, at the other end, to the propeller shaft, for instance, at the slider assembly. In another example, the propeller shaft assembly can include one conical spring provided in one of the two muffcups.
[0019] The conical spring can be detachably coupled to the muffcup as well
as the propeller shaft. As a result, the conical spring becomes a serviceable or replaceable component of the propeller shaft assembly, which in turn means that the serviceability of the propeller shaft is effective in terms of cost. In operation, the conical spring provides a cushion between the muffcup and the propeller shaft and acts as a safeguard in cases when the propeller shaft is moving in a direction away from the muff cups.
[0020] According to one example, the length and design of the conical
springs is such that in a neutral position, i.e., when the vehicle is on a

substantially level surface and the conical springs are not loaded, the conical springs constantly apply a preload on the ends of the propeller shaft to maintain each end of the propeller shaft at a mid-depth in the respective muffcup. In other words, the conical springs, i.e., the cushioning members, are preloaded to maintain the ends of the propeller shaft at substantially half of the total depth of the respective muffcup.
[0021] The conical spring, as the name suggests, has a conical shape and a
diameter of one end of the conical spring is smaller than a diameter of the other end, the diameter of the conical spring gradually increasing from the end having smaller diameter to the end having the larger diameter. Therefore, in the bump motion of the vehicle, when the effective distance between the two muffcups can reduce, the conical spring can compress to an extent that it has a thickness of diameter of the wire of the conical spring. In other words, when the conical spring compresses, it takes up only as much space in the muffcup as is the diameter of the wire that it is made of, thereby providing a substantial amount of space to accommodate the motion of the slider assembly in the muffcup. Accordingly, in the fully compressed state, a first end of the conical spring reaches a second end of the conical spring, for instance, the first end abuts the second end. At the same time, the thickness of the compressed conical spring, almost equal to the diameter of the spring wire, is enough to prevent the slider assembly at the end of the propeller shaft from knocking on the end wall of the muffcup. Accordingly, the operation of the propeller shaft assembly is substantially noiseless and the service life of the components is considerably long.
[0022] On the other hand, in the rebound motion, when the distance
between the muffcups can increase, the conical springs, which are coupled to the ends of the propeller shaft and constantly applying a preload on the ends of the propeller shaft, ensure that the force acting on the propeller shaft due

to the rebound motion is countered by the preload which protects the ends of the propeller shaft from breaking out of the respective muffcup.
[0023] Therefore, the propeller shaft assembly, in accordance with the
present subject matter, accommodates the variations in distance between two muffcups during a bump motion of the vehicle without compromising on the depth to which each end of a propeller shaft can move into the respective muffcup and, at the same time, preventing the ends of the propeller shaft from clashing against end walls of the respective muffcup. In addition, in the rebound motion, the propeller shaft assembly can accommodate the increase in distance between the two muffcups, however, preventing the propeller shaft from damaging the muffcups and breaking off. Further, the material of the conical spring is selected to have good fatigue properties so that even upon repeated cycles of compression and expansion, the spring has high service life.
[0024] The above aspects are further illustrated in the figures and
described in the corresponding description below. It should be noted that the description and figures merely illustrate principles of the present subject matter. Therefore, various arrangements that encompass the principles of the present subject matter, although not explicitly described or shown herein, may be devised from the description and are included within its scope.
[0025] Figure 1A illustrates a vehicle 100 having a propeller shaft assembly
102, according to an example of the present subject matter. Figure 1B illustrates a magnified view of the vehicle 100 showing the propeller shaft assembly 102, according to said example. For the sake of brevity and ease of understanding, Figure 1A and Figure 1B are described in conjunction with each other.
[0026] In the example shown in Figure 1A, the vehicle 100 can be a three-
wheeler. However, in other examples, the vehicle 100 can be a four-wheeled

vehicle or any other type of multi-wheeled vehicle, such as a passenger car or a commercial vehicle. Further, the propeller shaft assembly 102 can be coupled to transmit drive from a driving member 104 to a driven member 106. In said example, the driving member 104 can be an internal combustion engine or an electric motor to provide drive for propelling the vehicle 100, and the driven member 106 can be an axle or a wheel of the vehicle 100. In another example, the driven member 106 can be a differential. For instance, at the end of the driving member 104, the propeller shaft assembly 102 can be coupled to a crankshaft of the internal combustion engine or to an output shaft of a gearbox, thereby providing drive to the driven member 106. As will be understood, the propeller shaft assembly 102 is a part of a drive train of the vehicle 100.
[0027] According to an aspect of the present subject matter, the propeller
shaft assembly 102 accommodates the variations in distance between the driving member 104 and the driven member 106 during motions of the vehicle 100, for instance, over an uneven surface. As part of the operation, the propeller shaft assembly 102 can effectively accommodate a reduction in the effective distance while preventing parts of the propeller shaft assembly 102 from clashing into each other or producing noise. At the same time, the propeller shaft assembly 102 can accommodate the increase in the effective distance, however, preventing any damage or breakage of the propeller shaft assembly. This is explained in further detail with reference to Figure 2, Figure 3A, and Figure 3B.
[0028] Figure 2 illustrates an exploded view of the propeller shaft assembly
102 showing various components and parts of the propeller shaft assembly 102, according to an example of the present subject matter. In said example, the propeller shaft assembly 102 can include a propeller shaft 202 which forms the central connecting member of the propeller shaft assembly 102 to

transfer the drive from the driving member 104 to the driven member 106. The propeller shaft 202, at each end thereof, can have a slider assembly 204. At each end, the propeller shaft 202 can have a joint 206, such as a universal joint or a yoke joint, allow the propeller shaft assembly 102 to accommodate angular variations during motion of the vehicle 100. The slider assembly 204 can be formed in conjunction with the joint 206, at each end of the propeller shaft 202. For example, the slider assembly 204 can include a plurality of slider blocks 208, each having one or more channels 210 formed thereon for mating with a corresponding channel to slide thereon, as will be explained later.
[0029] The propeller shaft assembly can further include a plurality of
muffcups 212, each muffcup 212 provided at an end of the propeller shaft 202 to retain the slider assembly 204 at the respective end. In other words, the propeller shaft assembly 102 can include two muffcups 212, each having one slider assembly 204 positioned therein. The slider assemblies 204 can be slidably disposed in the respective muffcup 212 to accommodate variations in effective distance between the muffcups 212 when the vehicle 100 moves on an uneven surface. The muffcup 212 can be formed as a cylindrical, hollow component which is open at one end and closed at the other. The closed end can be closed by an end wall 214 and the open end of the muffcup 212 can receive the slider assembly 204. The muffcup 212 can have one or more complementary channels 210 formed on an internal lateral wall thereof, i.e., of the cylindrical body, to cooperate with the channels 210 formed on the slider block 208 of the slider assembly 204, thereby creating a sliding configuration between the slider assembly 204 and the muffcup 212, at each end of the propeller shaft 202.
[0030] In an example, the muffcups 212 can be terminal members of the
propeller shaft assembly 102. For example, one of the muffcups 212 can be

coupled to a crankshaft (not shown) of an engine or motor of the vehicle 100 or to an output shaft of a gearbox (not shown), whereas the other muffcup 212 can be coupled to a wheel shaft or axle or a differential of the vehicle 100.
[0031] According to an aspect, the propeller shaft assembly 102 further
includes at least one conical spring 216 disposed in a muffcup 212. In another example, the propeller shaft assembly 102 can include a plurality of conical springs 216, one disposed in each muffcup 212. The conical spring 216 can act as the cushioning member and is positioned in the muffcup 212 between the end wall 214 of the muffcup 212 and the end of the propeller shaft 202 that is retained in that muffcup 212. For instance, the conical spring 216 can be inside the muffcup 212 positioned between the end wall 214 of the muffcup 212 and the slider assembly 204.
[0032] One end of the conical spring 216 can be coupled to the end wall
214 of the muffcup 212 and the other end to the propeller shaft 202, i.e., the end of the propeller shaft 202, for instance, at the slider assembly 204. In an example, the conical spring 216 can be detachably coupled to the muffcup 212 as well as the end of the propeller shaft 202. As a result, the conical spring 216 is replaceable as a component of the propeller shaft assembly 102, which in turn means that in case of a damage, simply the conical spring 216 can be replaced instead of the entire assembly. Accordingly, the serviceability of the propeller shaft assembly 102 is effective in terms of cost.
[0033] According to one example, the conical springs 216 are designed in
such a way, for instance, in terms of length and the spring constant, that in a neutral position, i.e., when the vehicle 100 is on a substantially level surface, the conical springs 216 constantly apply a preload on the ends of the propeller shaft 202 to maintain each end of the propeller shaft 202 at a mid-depth in the respective muffcup 212. In other words, the conical springs 216 are

preloaded to maintain the ends of the propeller shaft 202 at substantially half of the total depth of the respective muffcup 212.
[0034] The conical spring 216 is made of a spring wire and, as the name
suggests, has a conical shape. A diameter of one end of the conical spring 216 is smaller than a diameter of the other end, and the diameter of the conical spring 216 gradually increases from the end having smaller diameter to the other end having the larger diameter. In operation, the conical spring 216 can provide a cushioning between the muffcup 212 and the propeller shaft 202 so that the two do not knock against each other. In addition, the conical spring 216 also acts as a safeguard in cases when the propeller shaft 202 is moving in a direction away from the muffcups 212 to prevent the ends of the propeller shaft 202 from being withdrawn from the muffcups 212. This operation of the conical spring 216 is explained with reference to Figure 3A and Figure 3B, as follows.
[0035] Figure 3A illustrates a cross-sectional view of the propeller shaft
assembly 102 in a bump motion of the vehicle 100, in accordance with an example of the present subject matter. For instance, the bump motion is exhibited by the vehicle 100 when the vehicle 100 drives over a raised bump on the road, during which time, the effective distance between the two muffcups 212 can reduce as a wheel of the vehicle 100 is raised and brought closer to a chassis of the vehicle 100.
[0036] As shown in Figure 3A, in the bump motion of the vehicle 100,
when the two muffcups 212 come closer than they are in the neutral position, the conical spring 216 in each muffcup 212 can compress to an extent that the thickness of compressed conical spring 216 is almost the same as a diameter of the spring wire that the conical spring 216 is made of. In other cases, the conical spring 216 can compress such that the first end of the conical spring 216 is in the proximity of the second end of the conical spring 216, the

proximity determined by, say the height of the bump over which the vehicle 100 is being driven. Owing to the conical shape of the conical spring 216, the coils of the conical spring 216 are accommodated in a concentric manner as the conical spring 216 compresses. Therefore, when the conical spring 216 compresses, it takes up only as much space in the muffcup 212 as is the diameter of its spring wire. Accordingly, a substantial amount of space is still available in the muffcup 212 to adequately accommodate the motion of the slider assembly 204. At the same time, the thickness of compressed conical spring 216 is enough to prevent the end of the propeller shaft 202, for instance, the slider assembly 204, in the muffcup 212 from knocking on the end wall 214 of the muffcup 212. Accordingly, the propeller shaft assembly 102, in accordance with the present subject matter, is capable of a substantially low-noise operation. At the same time, since the ends of the propeller shaft 202 do not clash with the end walls 214 of the muffcups 212, the wear and tear of the components, for example, the muffcups 212, the conical spring 216, and the slider assembly 204 is substantially low and the service life is considerably long.
[0037] Figure 3B illustrates a cross-sectional view of the propeller shaft
assembly 102 in a rebound motion of the vehicle 100, in accordance with an example of the present subject matter. For instance, the rebound motion is exhibited by the vehicle 100 when the vehicle 100 drives over a depression, such as a pothole, in the road. As the vehicle 100 drives through the depression in the road, the effective distance between the two muffcups 212 can increase from that in the neutral position, as the wheel of the vehicle 100 that enters the pothole is lowered and goes farther from the chassis of the vehicle 100.
[0038] In the rebound motion, owing to the fact that the conical springs
216 are coupled to the ends of the propeller shaft 202 and are constantly

applying a preload on the ends of the propeller shaft 202, the ends of the propeller shaft 202 are not allowed to withdraw from the muffcups 212. In other words, the force acting on the ends of the propeller shaft 202 due to the preloading of the conical spring 216, can counter the force acting on the muffcups 212 due to the rebound motion, which can otherwise cause the slider assemblies 204 to exit the respective muffcup 212. The presence of the conical springs 216, thereby protects, the ends of the propeller shaft 202 from breaking out of the respective muffcups 212.
[0039] Figure 4 illustrates a graph 400 which represents, as an example,
the forces acting on the ends of the propeller shaft 202 and the muffcups 212, during the operation of the vehicle 100. In said example, the y-axis of the graph 400 represents a force acting on the component in illustrative units, i.e., each end of the propeller shaft 202 and the muffcups 212, and the x-axis of the graph 400 represents the motion of the vehicle 100, i.e., the bump motion and the rebound motion. The graph 400 shows two plots - a first plot 402 for indicating the forces acting on the end of the end of the propeller shaft 202 during different motions of the vehicle 100, and second plot 404 indicating the forces acting on the muffcups 212 during the various motions of the vehicle 100.
[0040] As can from the first plot 402, the end of the propeller shaft 202
experiences a force of about 1 unit in the rebound motion of the vehicle 100, and experiences a force of about 5 units in the bump motion in the bump motion of the vehicle 100. However, in comparison, the second plot 404 shows that the each muffcup 212 experiences a force of about 0.5 units in the rebound motion of the vehicle 100 and experiences a force of about 3.5 units in the bump motion. In the laden condition, i.e., in the neutral motion of the vehicle 100, as illustrated by the first plot 402, the end of the propeller shaft 202 experiences a force of about 3 units. On the other hand, the muffcup 212,

in the laden condition, experiences a force of about 1.5 units, as shown by the second plot 404. Therefore, it is clear from the present example, that the preload on ends of the propeller shaft 202 due to the muffcups 212 allows for absorbing a considerable amount of force which the propeller shaft 202 would experience otherwise.
[0041] Although implementations of the propeller shaft assembly 102 are
described, it is to be understood that the present subject matter is not necessarily limited to the specific features of the systems or methods or other aspects described herein. Rather, the specific features are disclosed as implementations of the propeller shaft assembly 102.

I/We Claim:
1. A propeller shaft assembly (102) comprising:
a propeller shaft (202) having a first end and a second end;
a plurality of muffcups (212), one of the plurality of muffcups (212) to slidably retain the first end of the propeller shaft (202) and another of the plurality of muffcups (212) to slidably retain the second end of the propeller shaft (202); and
at least one cushioning member (216) disposed in one of the plurality of muffcups (212), wherein the at least one cushioning member (216) comprises a first end coupled to an end of the propeller shaft (202) and a second end coupled to an end wall (214) of the one of the plurality of muffcups (212), and wherein the cushioning member (216) is adapted to be compressed to an extent that the first end reaches the second end.
2. The propeller shaft assembly (102) as claimed in claim 1, wherein the cushioning member (216) is adapted to be compressed to the extent that the first end abuts the second end.
3. The propeller shaft assembly (102) as claimed in claim 1, wherein the cushioning member (216) is a conical spring (216).
4. The propeller shaft assembly (102) as claimed in claim 1, wherein the at least one cushioning member (216) is detachably attached to the end of the propeller shaft (202).
5. The propeller shaft assembly (102) as claimed in claim 1, wherein the at least one cushioning member (216) is preloaded to maintain the end of the propeller shaft (202) at substantially half of a total depth of the one of the plurality of muffcups (212) in a neutral position.
6. A propeller shaft assembly (102) comprising:
a propeller shaft (202) having a first end and a second end;

a plurality of muffcups (212), one of the plurality of muffcups (212) to slidably retain the first end of the propeller shaft (202) and another of the plurality of muffcups (212) to slidably retain the second end of the propeller shaft (202); and
a conical spring (216) disposed in each of the plurality of muffcups (212), wherein the conical spring (216) is positioned between and coupled to an end of the propeller shaft (202) and an end wall (214) of the muffcup (212).
7. The propeller shaft assembly (102) as claimed in claim 6, wherein the conical spring (216) is detachably attached to the end of the propeller shaft (202).
8. The propeller shaft assembly (102) as claimed in claim 6, wherein the conical spring (216) is preloaded to maintain the end of the propeller shaft (202) at substantially half of a total depth of the one of the plurality of muffcups (212) in a neutral position.
9. A vehicle (100) comprising:
a propeller shaft assembly (102) comprising,
a propeller shaft (202) having a first end and a second end;
a plurality of muffcups (212), one of the plurality of muffcups (212) to slidably retain the first end of the propeller shaft (202) and another of the plurality of muffcups (212) to slidably retain the second end of the propeller shaft (202); and
at least one cushioning member (216) disposed in one of the plurality of muffcups (212), wherein the at least one cushioning member (216) comprises a first end coupled to an end of the propeller shaft (202) and a second end coupled to an end wall (214) of the one of the plurality of muffcups (212), and wherein

the cushioning member (216) is adapted to be compressed to an extent that the first end reaches the second end.
10. The vehicle (100) as claimed in claim 9, wherein the vehicle (100) is a three-wheeler.
11. The vehicle (100) as claimed in claim 9, wherein, in a bump motion of the vehicle (100), the at least one cushioning member (216) is to compress to an extent that the first end is in proximity of the second end providing space for the first and the second end of the propeller shaft (202) to move in the respective muffcup (212).
12. The vehicle (100) as claimed in claim 9, wherein the at least one cushioning member (216) is to constantly apply a preload to the end of the propeller shaft (202) connected thereto, and wherein, in a rebound motion of the vehicle (100), the cushioning member (216) is to prevent at least the end of the propeller shaft (202) from being withdrawn from the muffcup (212).