[0001] The present invention relates to vehicles and, more particularly to, chain case for transmission chain of vehicle.

BACKGROUND

[0002] Generally, chain cases for two-wheeled vehicles such as motorcycle are of full-cover types which cover substantially the entire transmission chain. Such chain case includes an upper case member and a lower case member, and is provided with one or more mounting provisions for mounting the chain case to a swing arm of the two-wheeled vehicle. Typically, the upper case member and the lower case member are supported on the swing arm of the two-wheeled vehicle. During assembly, the upper case member is mounted to the swing arm such that it covers the upper half of the transmission chain and the lower case member is then mounted to the swing arm such that it covers the lower half of the transmission chain. Since, the upper case member and the lower case member are long bodies extending in longitudinal direction of the two-wheeled vehicle, there exists a tendency of the chain case members to deform in lateral direction. Such tendency of deformity of the chain case may lead to vibration and noise which is highly undesirable. To avoid this, as disclosed in Indian patent IN214900 titled "CHAIN CASE FOR MOTORCYCLE", a metallic bracket is welded to the swing arm and the middle portion of the upper case member and the lower case member are supported by such bracket. However, such bracket adds on to additional cost and processes which is undesirable. Further, there are multiple points where the upper case member and the lower case member are fixed to the swing arm, and it is always cumbersome to align the upper case member and the lower case member at multiple points with the swing arm.
SUMMARY

[0003] The invention is intended to negate the problems of conventional system. One of the objectives of the present invention is to provide an upper case member and a lower case member such that time required for aligning the upper case member and lower case member with the swing arm is reduced. Another objective of the present invention is to substantially prevent the lateral movement of outer side wall of the upper case member and lower case member so that the vibration and noise tendency is reduced or eliminated.
[0004] A chain case in a two-wheeled vehicle is disclosed. The two-wheeled vehicle comprising a chain and a swing arm swingably supported on a body frame of the two-wheeled vehicle. The swing arm at rear end portion supports a rear wheel of the two-wheeled vehicle, and the chain is adapted to rotate the rear wheel for movement of the two-wheeled vehicle. The chain case comprises an upper chain and a lower chain case.
[0005] The upper chain case is configured to at least partially cover an upper chain line of the chain. The upper chain line is a portion of the chain that is above the swing arm. The upper chain case comprises at least one set of upper claw members protruding from substantially middle portion of an outer side wall of the upper chain case. The at least one set of upper claw members is configured to abut against an outer tube of the swing. The lower chain case is configured to at least partially cover a lower chain line of the chain. The lower chain line is a portion of the chain that is below the swing arm. The lower chain case comprises at least one set of lower claw members protruding from substantially middle portion of an outer side wall of the lower chain case. The at least one set of lower claw members is configured to abut against the outer tube. At least one of the upper chain case and the lower chain case is coupled to the swing arm.
[0006] In an embodiment, each of the at least one set of upper claw members comprises two parts, where each part extends in opposite direction from an edge portion of the outer side wall and has substantially same profile of the outer tube of the swing arm so as to abut against the outer tube. The upper chain case has a substantially U-cross section with open end facing the swing arm. The substantially U-cross section formed by a top wall extending in frontward-rearward direction of the two-wheeled vehicle, and an inner side wall and the outer side wall extending downwardly from the top wall. The outer side wall at least partially covers the upper chain line.
[0007] In an embodiment, each of the at least one set of lower claw members comprises two parts, where each part extends in opposite direction from an edge portion of the outer side wall and has substantially same profile of the outer tube of the swing arm so as to abut against the outer tube. The lower chain case has a substantially U-cross section with open end facing the swing arm. The substantially U-cross section formed by a bottom wall extending in frontward-rearward direction of the vehicle, and an inner side wall and the outer side wall extending upwardly from the bottom wall. The outer side wall at least partially covers the lower chain line.
[0008] In an embodiment, the upper chain case further comprises one or more mounting provisions for mounting the upper chain case to the outer tube. The outer tube comprises a plurality of mounting provisions for engaging with corresponding provisions of the one or more mounting provisions of the upper chain case for mounting the upper chain case to the outer tube.
[0009] In an embodiment, the lower chain case further comprises one or more mounting provisions for mounting the lower chain case to the outer tube. The outer tube comprises a plurality of mounting provisions for engaging with corresponding provisions of the one or more mounting provisions of the lower chain case for mounting the lower chain case to the outer tube of the swing arm.
[0010] The swing arm comprises a pair of elongated tubes comprising an inner tube and the outer tube, front parts of which are connected by a cross plate.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[0011] The invention itself, together with further features and attended advantages, will become apparent consideration of the following description, taken in conjunction with the accompanying drawings. One or more embodiments of the present invention are now described, by way of example only, with reference to the accompanied drawings wherein like reference numerals represent like elements and in which:
[0012] Figure 1 depicts a schematic view of a body frame of a two-wheeled vehicle;
[0013] Figure 2 illustrates an exploded view depicting an upper chain case, a lower chain case and a swing arm, according to an embodiment of the present invention;
[0014] Figure 3 illustrates the upper chain case, the lower chain case and the swing arm in assembled condition, according to an embodiment of the present invention;
[0015] Figure 4 illustrates enlarged view of the portion encircled in the Figure 3, according to an embodiment of the present invention;
[0016] Figure 5 illustrates a sectional view of the Figure 3 along the line A-A; and
[0017] Figure 6 illustrates a section view of the Figure 3 along the line B-B.
[0018] The drawings referred to in this description are not to be understood as being drawn to scale except if specifically noted, and such drawings are only exemplary in nature.

DETAILED DESCRIPTION

[0019] While the invention is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and will be described here. It should be understood, however that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternative falling within the spirit and the scope of the invention.
[0020] The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, device or method that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device or method. In other words, one or more elements in a system or apparatus proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or apparatus.
[0021] For the better understanding of this invention, reference would now be made to the embodiment illustrated in greater depth in the accompanying figures and description here below, further, in the following figures, the same reference numerals are used to identify the same components in various views.
[0022] The terms “front / forward”, “rear / rearward / back / backward”, “up / upper / upward”, “down / downward / lower / lowerward” that may be used therein represent the directions as seen from a vehicle driver sitting astride and these directions are referred by arrows Fr, Rr, U, Lr in the drawing figures. Further, “left / leftward”, “right / rightward” that may be used herein represent the directions as seen from a vehicle driver sitting astride.
[0023] While the present invention is illustrated in the context of a saddle riding type vehicle, however, the chain case structure as described herein, aspects and features thereof can be used with other type of vehicles as well, including without limitation, scooter type vehicles, motorcycles, mopeds, all off road type vehicles or the like. It may be noted that the terms “saddle riding type vehicle” or “vehicle” or “two wheeled vehicle” are interchangeably used in the description and refers to the saddle riding type vehicle such as a two-wheeled vehicle.
[0024] Figure 1 depicts a schematic view of a body frame (100) of a two-wheeled vehicle. As shown in the Figure 1, the body frame (100) includes, inter-alia, a main frame member (101), down tube members (112a) & (112b), seat rail members (154a) and (154b), a pair of sub-frame members (156a) and (156b), a pair of pivot plate members (110a) and (110b) and a head tube (113). The head tube (113) extends frontward and downward from the main frame member (101) in the front part thereof, and is coupled to front wheel (not shown in figures) so that steering is possible with a handlebar (115). The pivot plate members (110a) and (110b) extend rearward and downward from the rear portion of the main frame member (101). The seat rail members (154a) and (154b) extend rearward from the rear portion of the pivot plate members (110a) and (110b) primarily for supporting a seat (not shown in figure). The down tube members (112a) and (112b) extend from a front portion thereof of the main frame member (101) in rearward and downward direction and then rearward in substantially the horizontal direction and at the other ends are joined with the pivot plate members (110a) and (110b), directly or through a cross bar. The sub-frame members (156a) and (156b) extend diagonally downward and forward from a longitudinally intermediate portion thereof of the seat rail members (154a) and (154b) and at other ends are joined with the corresponding pivot plate members (110a) and (110b). An integrated brake actuating means (120) such as a brake pedal is pivotally mounted to a bracket fixed to the bottom portion of the pivot plate members (110a) and (110b). A swing arm (104) is pivotally mounted to the body frame (100) for swingably supporting the rear wheel (not shown in any figures) of the vehicle.
[0025] Figures 2 and 3 illustrate an upper chain case, a lower chain case and a swing arm in exploded and assembled state respectively, according to an embodiment of the present invention. Generally, the two-wheeled vehicle includes an engine supported by the vehicle body frame (100) and the swing arm (104) swingably supported at the front end by the body frame (100) and a wheel is supported at the rear end of the swing arm (104). A transmission chain (150) (also referred to as 'chain (150)') is suspended between a drive sprocket on one side of the engine and a driven sprocket on same side of the rear wheel. The chain (150) passes above and below the swing arm (104). More specifically, an upper chain line passes above the swing arm (104) and a lower chain line passes below the swing arm (104). A chain case is mounted to the swing arm (104) and is adapted to cover the chain (150) on the upper and lower side of the swing arm (104), and the chain case is configured to swing integrally with the swing arm (104). As illustrated in Figures 2 and 3, the chain case includes an upper chain case (102) and a lower chain case (106). The upper chain case (102) includes a top wall (40) extending in the frontward-rearward direction of the vehicle, an outer side wall (42) and an inner side wall (44) extending downwardly from the top wall (40) to form a U-shaped cross section (refer Figures 5 or 6). The open end of the U-shaped upper chain case (102) opens towards the swing arm (104). Similarly, the lower chain case (106) includes a bottom wall (46) extending in the frontward and rearward direction of the vehicle, an outer side wall (49) and an inner side wall (48) extending in the upward from the bottom wall (46) to form a U-shaped cross section (refer Figures 5 or 6). The open end of the U-shaped lower chain case (106) opens towards the swing arm (104).
[0026] Further, the upper chain case (102) includes at least one set of upper claw members (12). Each set of upper claw members (12) is formed on the outer side wall (42) at substantially middle portion of the outer side wall (42). In an embodiment, the set of upper claw members (12) is an integral portion of the outer side wall (42). However, in some other embodiments, the upper claw members (12) may be configured separately and attached to substantially middle portion of the outer side wall (42). Similarly, the lower chain case (106) includes at least one set of lower claw members (10). Each set of lower claw members (10) is formed on the outer side wall (49) at substantially middle portion of the outer side wall (49). In an embodiment, the set of lower claw members (10) is an integral portion of the outer side wall (49). However, in some other embodiments, the lower claw members (10) may be configured separately and attached to substantially middle portion of the outer side wall (49).
[0027] As shown in Figure 2, the swing arm (104) includes a pair of tubes for example, an inner tube (26) and an outer tube (28) which are coupled to each other at their front end parts through a cross plate (30). The outer tube (28) extends between the upper and lower chain lines of the chain (150) in the front and rear direction. At least one of the upper chain case (102) and the lower chain case (106) are attached to the outer tube (28). For instance, in an embodiment, either the upper chain case (102) or the lower chain case (106) is attached to the outer tube (28). In another embodiment, both of the upper chain case (102) and the lower chain case (106) are attached to the outer tube (28). Further, a plurality of mounting provisions (20, 24, 38 and 34) are provided on the outer tube (28) of the swing arm (104) for mounting the upper chain case (102) and the lower chain case (106). In an embodiment, the mounting provisions (20, 24, 38 and 34) are provided in the form of brackets integrally formed on the swing arm (104). The mounting provisions (24) and (38) have through openings (24b) and (38b) respectively, and corresponding provisions such as openings (24a) and (38a) are provided on the outer wall (42) of the upper chain case (102) to mount the upper chain case (102) to the swing arm (104). Similarly, the mounting provisions (20) and (34) have through openings (20b) and (34b) respectively, and corresponding provisions such as openings (20a) and (34a) are provided on the outer side wall (49) of the lower chain case (106) to mount the lower chain case (106) to the swing arm (104).
[0028] As illustrated in the Figures 5 and 6, a set of upper claw members (12) may be configured in form of two parts, each extending in opposite direction from an edge portion of the outer side wall (42) of the upper chain case (102). In an embodiment, the upper claw members (12) are arc shaped structure and are contoured substantially the same as that of the profile of the outer tube (28) of the swing arm (104). In an embodiment, the upper claw members (12) are disposed next to each other so as to be in opposed relationship. In an embodiment, the upper claw members (12) are disposed at different positions along the length of the outer tube (28) of the swing arm (104). Dimension of the arced first upper claw members (12) is maintained in such manner that the upper claw members (12) restrict the lateral movement of the outer side wall (42) of the upper chain case (102). In an embodiment, the portion (42e) of the free edge of the outer wall (42) of the upper chain case (102) where the arced first upper claw members (12) are disposed, is provided elevated than the portion (42m) of the free edge of the outer wall (42) where the openings (24a and 38a) are provided. For assembling the upper chain case (102) in the vehicle, particularly to the swing arm (104), the portion (42e) of the free edge of the outer wall (42) is abutted to the outer tube (28) of the swing arm (104) and the openings (24b) and (38b) of the mounting provisions (24) and (38), respectively, get aligned in vertical direction with the corresponding openings (24a) and (38a) of the outer wall (42) of the upper chain case (102). In this manner, the upper chain case (102) is fixed with the swing arm (104).
[0029] Similarly, as illustrated in the Figures 5 and 6, a set of upper claw members (12) may be configured in form of two parts, each extending in opposite direction from the outer side wall (49) of the lower chain case (106). In an embodiment, the lower claw members (10) are arc shaped structure. In an embodiment, the lower claw members (10) are contoured substantially the same as that of the profile of the outer tube (28) of the swing arm (104). In an embodiment, the lower claw members (10) are disposed next to each other so as to be in opposed relationship. In an embodiment, the lower claw members (10) are disposed at different positions along the length of the outer tube (28) of the swing arm (104). Dimension of the lower claw members (10) is maintained in such manner that the lower claw members (10) restrict the lateral movement of the outer side wall (49) of the lower chain case (106). In an embodiment, the portion (49e) of the free edge of the outer side wall (49) of lower chain case (106), where the arced first lower claw members (10) are disposed, is provided elevated than the portion (49m) of the free edge of the outer side wall (49) where the openings (20a) and (34a) are provided. For assembling the lower chain case (106) in the vehicle, particularly to the swing arm (104), the portion (49e) of the free edge of the outer side wall (49) is abutted to the outer tube (28) of the swing arm (104) and the openings (20b) and (34b) of the mounting provisions (20) and (34) respectively get aligned in vertical direction with the corresponding openings (20a) and (34a) of the outer side wall (49) of the lower chain case (106). In this manner, the lower chain case (106) is fixed with the swing arm (104).
[0030] Without in any way limiting the scope, interpretation, or application of the claims appearing below, a technical effect of one or more of the example embodiments disclosed herein is to provide mechanisms to preclude lateral bending of upper and lower chain cases used in two-wheeled vehicles. It is noted that one or more set of claw members (e.g., the lower claw members (10) and the upper claw members (12)) are provided on the upper chain case (104) and the lower chain case (106), respectively, and the claw members (10, 12) are contoured with same profile of the outer tube (28). Accordingly, in the assembled state, the claw members (10, 12) restrict the lateral movement of the upper and lower chain cases, as the claw members (10, 12) overlap (or abut) with a peripheral portion of the outer tube (28).
[0031] While few embodiments of the present invention have been described above, it is to be understood that the invention is not limited to the above embodiments and modifications may be appropriately made thereto within the spirit and scope of the invention.
[0032] While considerable emphasis has been placed herein on the particular features of this invention, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiments without departing from the principles of the invention. These and other modifications in the nature of the invention or the preferred embodiments will be apparent to those skilled in the art from the invention herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

CLAIMS
We claim:
1. A chain case in a two-wheeled vehicle, the two-wheeled vehicle comprising a chain (150) and a swing arm (104) swingably supported on a body frame (100) of the two-wheeled vehicle, the swing arm (104) at rear end portion supporting a rear wheel of the two-wheeled vehicle, the chain (150) adapted to rotate the rear wheel for movement of the two-wheeled vehicle, the chain case comprising:
an upper chain case (102) for at least partially covering an upper chain line of the chain (150), the upper chain line being a portion of the chain (150) that is above the swing arm (104), the upper chain case (102) comprising at least one set of upper claw members (12) protruding from substantially middle portion of an outer side wall (42) of the upper chain case (102), the at least one set of upper claw members (12) configured to abut against an outer tube (28) of the swing arm (104); and
a lower chain case (106) for at least partially covering a lower chain line of the chain (150), the lower chain line being a portion of the chain (150) that is below the swing arm (104), the lower chain case (106) comprising at least one set of lower claw members (10) protruding from substantially middle portion of an outer side wall (49) of the lower chain case (106), the at least one set of lower claw members (10) configured to abut against the outer tube (28),
wherein at least one of the upper chain case (102) and the lower chain case (106) is coupled to the swing arm (104).

2. The chain case as claimed in claim 1, wherein each of the at least one set of upper claw members (12) comprises two parts, each part extending in opposite direction from an edge portion of the outer side wall (42) and has substantially same profile of the outer tube (28) of the swing arm (104) so as to abut against the outer tube (28).

3. The chain case as claimed in claims 1 or 2, wherein the upper chain case (102) has a substantially U-cross section with open end facing the swing arm (104), the substantially U-cross section formed by:
a top wall (40) extending in frontward-rearward direction of the two-wheeled vehicle; and
an inner side wall (44) and the outer side wall (42), each extending downwardly from the top wall (40),
wherein the outer side wall (42) at least partially covers the upper chain line.

4. The chain case as claimed in claim 1, wherein each of the at least one set of lower claw members (10) comprises two parts, each part extending in opposite direction from an edge portion of the outer side wall (49) and has substantially same profile of the outer tube (28) of the swing arm (104) so as to abut against the outer tube (28).

5. The chain case as claimed in claims 1 or 4, wherein the lower chain case (106) has a substantially U-cross section with open end facing the swing arm (104), the substantially U-cross section formed by:
a bottom wall (46) extending in frontward-rearward direction of the vehicle; and
an inner side wall (48) and the outer side wall (49), each extending upwardly from the bottom wall (46),
wherein the outer side wall (49) at least partially covers the lower chain line.

6. The chain case as claimed in claim 1, wherein the upper chain case (102) further comprises one or more mounting provisions for mounting the upper chain case (102) to the outer tube (28).

7. The chain case as claimed in claim 6, wherein the outer tube (28) comprises a plurality of mounting provisions (24) and (38) for engaging with corresponding provisions (24a) and (38a) of the one or more mounting provisions of the upper chain case (102) for mounting the upper chain case (102) to the outer tube (28).

8. The chain case as claimed in claim 1, wherein the lower chain case (106) further comprises one or more mounting provisions for mounting the lower chain case (106) to the outer tube (28).

9. The chain case as claimed in claim 8, wherein the outer tube (28) comprises a plurality of mounting provisions (20) and (34) for engaging with corresponding provisions (20a) and (34a) of the one or more mounting provisions of the lower chain case (106) for mounting the lower chain case (106) to the outer tube (28) of the swing arm (104).

10. The chain case as claimed in claim 1, wherein the swing arm (104) comprises a pair of elongated tubes comprising an inner tube (26) and the outer tube (28), front parts of which are connected by a cross plate (30).