JP5340776B2 - Motorcycle chain case - Google Patents

Description

  The present invention relates to a motorcycle chain case that covers substantially the entire chain.

2. Description of the Related Art Conventionally, there is a full-cover type chain case for a motorcycle that covers substantially the entire chain. This chain case has an upper case and a lower case, and a sound plate is provided on the inner surface of the bottom wall of the lower case. The chain comes into contact with this sound plate and the sound generated when sliding on the upper surface of the sound plate The passenger is informed of the elongation (see, for example, Patent Document 1).
Japanese Patent No. 3877347

However, in the above-described conventional configuration, the generated sound is small unless the chain is sufficiently extended and in contact with the upper surface of the sound plate. Therefore, the chain is sufficiently extended to increase the contact area between the sound plate and the chain. Otherwise, the crew would have difficulty recognizing the chain extension.
Accordingly, an object of the present invention is to provide a chain case for a motorcycle that allows an occupant to recognize the extension of the chain before the chain is sufficiently extended.

  In order to solve the above-mentioned problems, the present invention comprises an engine supported by a body frame, and a swing arm whose front end is swingably supported by the body frame and rotatably supports a rear wheel at the rear end, An upper case that covers a chain that passes over the upper side of the swing arm, and a lower case that covers the chain that passes under the swing arm; and a chain between the drive sprocket on the engine side and the driven sprocket on the rear wheel side A chain case of a motorcycle in which a chain case having a chain is supported on the swing arm, and has a surface crossing a direction in which the chain moves, and the chain and an upper end of the surface when the chain extends more than a predetermined amount. A plate-like protrusion is provided at the lower part of the inner surface of the lower case so that the

  In the motorcycle chain case, a plurality of the protrusions may be provided on the lower surface of the inner surface of the lower case with a space therebetween.

  In the motorcycle chain case, the lower case includes a bottom wall portion extending in the vehicle front-rear direction and a pair of left and right side wall portions extending from the bottom wall portion toward the swing arm, and is opened upward. A U-shaped cross section may be formed, and a gap may be provided between the protrusion and at least one of the bottom wall portion and the pair of left and right side wall portions.

  In the motorcycle chain case, the lower case may be provided with a confirmation window on the side wall portion located outside the vehicle in a range where the plurality of protrusions are provided and above the protrusions. .

  The chain case of the motorcycle may be formed integrally with the lower case so as to extend inward from the bottom wall portion of the lower case or the inner surfaces of the pair of left and right side walls.

  In the motorcycle chain case, the protrusion may be provided on the lower case so as to stand vertically in the vertical direction, and the chain case may be made of resin.

  According to the present invention, the plate-like protrusion is formed on the lower part of the inner surface of the lower case so that the chain has a surface that crosses the moving direction of the chain and the chain and the upper end of the surface come into contact when the chain extends beyond a predetermined amount. As a result, the chain does not slide on the surface of the protrusion, but only hits the upper end of the surface, so that the sound of the contact between the chain and the protrusion can be struck, and the chain slides on the surface of the sound plate. With a loud sound compared to the sound generated when touching, the crew can be informed of chain growth. As a result, the occupant can recognize the extension of the chain before the chain is sufficiently extended.

  In addition, since a plurality of protrusions are provided on the lower part of the inner surface of the lower case with a gap, a chain extending more than a predetermined amount hits each protrusion and a plurality of hitting sounds are generated. Becomes easier to recognize.

  The lower case includes a bottom wall portion extending in the vehicle front-rear direction and a pair of left and right side wall portions extending from the bottom wall portion toward the swing arm. Since there is a gap between the projection and at least one of the pair of left and right side wall portions, there is a gap between the projection and at least one of the pair of left and right side wall portions. It is possible to suppress accumulation of water and the like.

  In addition, the lower case is provided with a confirmation window on the side wall located on the outer side of the vehicle within the range where a plurality of protrusions are provided and above the protrusion. Therefore, it is possible to confirm the elongation of the chain and to check whether gravel or the like is accumulated between the protrusions. Further, when the chain is in contact with the protrusion, it is possible to confirm how the protrusion is reduced due to the contact with the chain.

  Furthermore, since the protrusion is formed integrally with the lower case so that the protrusion extends inward from the bottom wall portion of the lower case or the inner surfaces of the pair of left and right side wall portions, the fastener for attaching the protrusion to the lower case Etc. are not required, and the number of parts can be reduced.

  In addition, since the lower case has a U-shaped cross section that opens upward, and the protrusions stand upright in the vertical direction, it is easy to create a resin chain case. Further, since the hitting sound of the chain and the protrusion hits, it is possible to notify the occupant of the chain extension even in the case of a resin chain case.

Preferred embodiments of the present invention will be described below with reference to the drawings. In the description, descriptions of directions such as front and rear, right and left and up and down are for the vehicle body.
FIG. 1 is a side view showing a motorcycle to which a chain case according to the present embodiment is applied, and FIG. 2 is a view showing the motorcycle of FIG. 1 with a body cover or the like removed.
A body frame 2 of the motorcycle 1 includes a head pipe 3 at the front of the vehicle body, a main frame 4 that extends rearward and downward from the head pipe 3, and a rear portion of the main frame 4 that extends downward. A pair of left and right pivot brackets 5 and 5, a pair of left and right rear frames 6 and 6 that are connected to the rear portion of the main frame 4 and extend rearward, and are bridged between the main frame 4 and the rear frames 6 and 6. And a pair of left and right reinforcing frames 7.
A fuel tank 8 is supported on the reinforcement frames 7, 7, and an occupant seat 9 is supported on the upper portion of the fuel tank 8 so as to be freely opened and closed with the front end side as a rotation fulcrum. The occupant seat 9 is configured to also serve as a lid that covers a fuel filler opening provided above the fuel tank 8 so as to be exposed to the outside.

Further, a handle 10 pivotally supported by the head pipe 3 is provided above the front part of the vehicle body, front forks 11 and 11 extend below the handle 10, and a front wheel 12 is pivotally supported at the lower end thereof. A swing arm 40 is pivotally supported by pivot brackets 5 and 5 at the center of the vehicle body via a pivot shaft 13 so that the front end of the swing arm 40 can swing. The swing arm 40 extends rearward. Is supported. A pair of left and right rear cushions 16, 16 are interposed between the rear part of the swing arm 40 and the rear frames 6, 6.
An engine (also referred to as a power unit) 20 is suspended below the main frame 4 and in front of the pivot brackets 5 and 5. The upper part of the engine 20 is suspended by support brackets 17 and 17 suspended from the center of the main frame 4, and the rear part of the engine 20 is fixed to the upper and lower parts of the pivot bracket 5.

The engine 20 is a single-cylinder four-cycle air-cooled engine, and the cylinder portion 21 is largely inclined forward from the front surface of the crankcase 22 to a state that is substantially horizontal. As a result, the center of gravity of the vehicle body can be lowered, and as shown in the figure, the main frame 4 can be lowered to lower the straddling portion M on which the driver straddles when getting on, thereby improving boarding / exiting performance.
An air cleaner 23 is attached to the front lower side of the main frame 4 and in front of the engine 20. A mixed gas obtained by mixing the air supplied from the air cleaner 23 and the fuel supplied from the fuel tank 8 is burned in the cylinder portion 21, and the exhaust gas is discharged through the exhaust pipe 24 and the muffler 25.

An output shaft (not shown) of the engine 20 is pivotally supported at the rear left side of the crankcase 22 of the engine 20 with its tip exposed, and a drive sprocket 27 is attached to the tip of the output shaft. A chain 29 is wound between the drive sprocket 27 and a driven sprocket 28 provided integrally with the rear wheel 15, whereby a chain transmission mechanism for transmitting the output shaft power to the rear wheel 15 is provided. Composed. Thereby, the power of the engine 20 is transmitted to the rear wheel 15 through this chain transmission mechanism.
A chain case 50 that covers the chain 29 is attached to the swing arm 40 so as to swing integrally.

  The body frame 2 is covered with a synthetic resin body cover 18 that is divided into various parts. The vehicle body cover 18 is formed integrally with a pair of left and right main frame side covers 18A covering both sides of the main frame 4 and the left and right sides of the main frame side cover 18A so as to cover the occupant's legs from the front. A pair of leg shields 18B, a front top cover 18C connected to both leg shields 18B so as to cover the head pipe 3 from the front side, a handle cover 18D covering the handle 10, a rear portion of the vehicle body frame 2, and the fuel tank 8 are both included. A pair of left and right rear side covers 18E that covers from both sides are provided.

In FIG. 1, reference numeral 19 </ b> A is a front fender that is attached between the front forks 11 and 11 and covers the upper part of the front wheel 12, and reference numeral 19 </ b> B is a rear fender that is attached to the rear frames 6 and 6 and covers the upper part of the rear wheel 15. It is.
A headlight 30 is provided in front of the head pipe 3 so as to be exposed from the handle cover 18D to the front of the vehicle body. A loading platform 31 is supported on the upper part of the rear frames 6, 6, and a tail lamp 32 is provided behind the loading platform 31.

FIG. 3 is an exploded perspective view showing the swing arm 40 and the chain case 50. FIG. 4 is a side view showing the upper case of the chain case 50, and FIG. 5 is a side view showing the lower case of the chain case 50. FIG. 6 is a longitudinal sectional view showing the lower case from the front. FIG. 7 is a side view showing the chain case 50.
As shown in FIGS. 1 and 3, the chain 29 passes through the upper and lower sides of the swing arm 40, and forms an upper chain line 29A and a lower chain line 29B.
The swing arm 40 includes a pair of left and right arm pipes 41 </ b> A and 41 </ b> B, each of which is connected via a cross member 42 at the front end. The left arm pipe 41A extends in the front-rear direction between the upper and lower chain lines 29A, 29B of the chain 29 in a side view, and a chain case 50 is attached thereto.

Bearings 43A and 43B are attached to the front ends of the arm pipes 41A and 41B. A lower end portion of the rear cushion 16 is supported at the upper rear end portion of the left arm pipe 41A, and a first stay 44 for supporting the chain case 50 is attached, and a rear cushion 16 is disposed at the upper rear end portion of the right arm pipe 41B. A second stay 45 is attached to which a lower end of the second stay 45 is supported. A third stay 44D that supports the chain case 50 is attached to the lower end of the left arm pipe 41A. At the rear ends of the arm pipes 41A and 41B, elongated holes 44A and 45A for supporting the axle of the rear wheel 15 are formed. Further, support members 44 </ b> B and 45 </ b> B for supporting the lower end portion of the rear cushion 16 are attached to the first stay 44 and the second stay 45. A screw hole 44C is formed in the first stay 44 at the vehicle rear side of the support member 44B. Also, a screw hole 44E is formed at the tip of the third stay 44D that protrudes downward from the lower rear end of the left arm pipe 41A.
At the left end of the cross member 42, mounting stays 46, 46 projecting up and down are provided. A through hole 46A is provided at the tip of each of the upper and lower mounting stays 46, and a weld nut (not shown) is provided on the inner surface side of the hole position.

  The chain case 50 is made of a resin material such as polypropylene, and includes an upper case 60 and a lower case 70. As shown in FIGS. 3 and 4, the upper case 60 includes an upper wall portion 61 that extends in the vehicle longitudinal direction, and a pair of left and right side wall portions 62 that extend downward from the upper wall portion 61 toward the swing arm 40. 63 and has a U-shaped cross section that opens downward. A long hole 64 is formed at a position corresponding to the through hole 46A of the mounting stay 46 in the side wall portion 62 located on the vehicle outer side (left side), and the through hole is formed at a position corresponding to the screw hole 44C of the first stay 44. 65 is formed. Further, the side wall portion 62 is formed with a relief portion 66 of the rear cushion 16 which is adjacent to the through hole 65 and is recessed inward of the chain case 50. An escape portion 67 of the driven sprocket 28 (see FIG. 1) is formed in the side wall portion 63 located on the vehicle inner side (right side).

  As shown in FIGS. 3 and 5, the lower case 70 includes a bottom wall portion 71 extending in the vehicle longitudinal direction, and a pair of left and right side wall portions 72 extending upward from the bottom wall portion 71 toward the swing arm 40. 73 and has a U-shaped cross section that opens upward. The bottom wall portion 71 is inclined downward and rearward in a side view, and the first and second portions for discharging gravel, water and the like that have entered the chain case 50 to the lower position of the rear portion of the lower case 70 are discharged. Two discharge holes 71A and 71B are formed. A long hole 74 is formed at a position corresponding to the through hole 46A of the mounting stay 46, and a through hole 75 is formed at a position corresponding to the screw hole 44E of the first stay 44 in the side wall portion 72 located on the vehicle outer side. Has been. An escape portion 76 of the driven sprocket 28 (see FIG. 1) is formed in the side wall portion 73 located on the vehicle inner side.

As shown in FIG. 3, in the rear part of the chain case 50, the through hole 65 is matched with the screw hole 44C formed in the first stay 44, and the through hole 75 is matched with the screw hole 44E formed in the third stay 44D. Then, the bolt 47 is fastened to the screw hole 44C and the screw hole 44E via the washer 48, thereby being attached to the swing arm 40.
The front portion of the chain case 50 has the long holes 64 and 74 aligned with the through holes 46A formed in the upper and lower mounting stays 46, and the bolts 47 are fastened to the weld nuts provided in the upper and lower mounting stays 46. Attached to the swing arm 40.

  A confirmation window 77 for confirming the inside of the lower case 70 is formed on the side wall portion 72 of the lower case 70. The confirmation window 77 is disposed slightly forward of the center of the lower case 70 in the longitudinal direction of the vehicle and slightly below the center of the lower case 70 in the vertical direction. A cap 78 is detachably fitted to the confirmation window 77. The cap 78 may be made of a transparent resin. Moreover, you may form the confirmation window which has an internal confirmation function similarly to a window hole by making a part of lower case 70 partially transparent.

As shown in FIG. 5, a plurality (10 in the present embodiment) of protrusions 80 extending in the vehicle width direction are provided side by side in the vehicle front-rear direction on the bottom wall portion 71 in the vicinity of the confirmation window 77. Each protrusion 80 has a front surface (surface) 80A and a rear surface (surface) 80B orthogonal to the vehicle front-rear direction (left-right direction in FIG. 5) and is formed in a thin plate shape, and the thickness is 1.5 mm, for example. Set to These protrusions 80 are parallel to each other and arranged at equal intervals. As shown in FIG. 6, each projection 80 is formed in a rectangular shape when viewed from the front, and includes a pair of left and right side portions 81, 82, an upper portion (upper end) 83, and a lower portion 84. In the present embodiment, the side portion 82 on the right side of the vehicle is integrated with the inner surface of the side wall portion 73 located on the inner side of the vehicle, and the lower portion 84 is integrated with the inner surface of the bottom wall portion 71. That is, each protrusion 80 is provided so as to extend inward from the inner surfaces of the bottom wall portion 71 and the side wall portion 73 of the lower case 70. Thus, since each protrusion 80 is integrally formed with the lower case 70, a fastener or the like for attaching the protrusion 80 to the lower case 70 becomes unnecessary, and the number of parts can be reduced.
Each projection 80 is provided on the lower case 70 so as to stand vertically in the vertical direction. Accordingly, each projection 80 extends in substantially the same direction as the pair of left and right side wall portions 72, 73 extending upward, and therefore, the resin chain case 50 can be easily created.

The left side portion 81 is separated from the side wall portion 72 located on the vehicle outer side, and a gap 90 is provided between the protrusion 80 and the side wall portion 72. The gap 90 is set to a size such that gravel, water, or the like that has entered between the protrusions 80 can be discharged toward the first and second discharge holes 71A and 71B (see FIG. 5). Accordingly, since there is a sufficient gap 90 on the left side of the protrusion 80, accumulation of gravel, water, etc. between the protrusion 80 and the protrusion 80 is suppressed, and gravel, water, etc. are indicated by dotted arrows in FIG. It is discharged to the first and second discharge holes 71A, 71 B to. Further, as shown in FIG. 6, since the gap 90 is provided on the side wall portion 72 side where the confirmation window 77 is formed, it is easy to check whether gravel or the like is accumulated between the projections 80 and 80. In addition, when gravel is accumulated, it is possible to easily remove the accumulated gravel from the confirmation window 77.
As shown in FIG. 7, the protrusion 80 is provided at a position where the chain 29 extending in a side view is closest to the bottom wall portion 71. The height of the protrusion 80 from the bottom wall portion 71 is set so as to contact the protrusion 80 when the chain 29 extends to a predetermined amount.

  When the chain 29 extends beyond a predetermined amount, the lower chain line 29B hits the protrusion 80 provided on the lower case 70. The protrusion 80 emits a sound when the chain 29 hits, and serves to inform the occupant of the extension of the chain 29. At this time, each protrusion 80 is formed in a thin plate shape having surfaces 80A and 80B crossing the direction A in which the chain 29 moves, so that the chain 29 does not slide on the surface but the plate-like protrusion 80 The upper part 83 (see FIG. 6) and the chain 29 can be applied. As a result, the protrusion 80 is repelled by the chain 29 and can generate a hitting sound. The chain 80 is louder than the sliding contact sound generated when the chain 29 slides on the surface, and the chain 29 extends to the occupant. Can be informed. Further, since the protrusion 80 is formed in a thin plate shape, it is easy to vibrate and can generate a larger hitting sound. In addition, since a plurality of protrusions 80 are provided at intervals on the lower part of the inner surface of the lower case 70, the chain 29 can hit each protrusion 80 to generate a plurality of hitting sounds, and the occupant can extend the chain 29. Becomes easier to recognize. Thus, since the hitting sound between the chain 29 and the protrusion 80 is used as a hitting sound, it is possible to notify the passenger of the extension of the chain 29 even in the case of the resin chain case 50.

  The above-described confirmation window 77 is provided in a range W where the plurality of protrusions 80 are provided in a side view and at a position above the protrusions 80. Accordingly, since the periphery of the protrusion 80 in the chain case 50 can be easily visually confirmed from the confirmation window 77, it is possible to confirm the extension of the chain 29 from the confirmation window 77 and gravel between the protrusion 80 and the protrusion 80. It becomes possible to confirm whether etc. have accumulated. In addition, when the chain 29 is in contact with the protrusion 80, it is possible to check how the protrusion 80 is reduced due to the contact with the chain 29.

  As described above, according to the present embodiment, there are surfaces 80A and 80B that cross the moving direction A of the chain 29, and when the chain 29 extends beyond a predetermined amount, the chain 29 and the surfaces 80A and 80B A plate-like protrusion 80 is provided on the lower part of the inner surface of the lower case 70 so as to contact the upper part 83. As a result, the chain 29 does not slidably contact the surface of the protrusion 80, but only hits the upper portion 83 of the surfaces 80A and 80B. The occupant can be informed of the extension of the chain 29 with a loud sound compared to the sound generated when sliding on the surface of the sound plate. As a result, it is possible to make the occupant recognize the extension of the chain 29 before the chain 29 is sufficiently extended.

  Further, according to the above embodiment, the plurality of protrusions 80 are provided at a lower portion of the inner surface of the lower case 70 with a space therebetween, so that the chain 29 extending a predetermined amount or more hits each protrusion 80 and a plurality of hits. Since the sound is generated, it becomes easier for the occupant to recognize the extension of the chain 29.

  Further, according to the embodiment, the lower case 70 includes the bottom wall portion 71 extending in the vehicle front-rear direction, and the pair of left and right side wall portions 72 and 73 extending from the bottom wall portion 71 toward the swing arm 40. And has a U-shaped cross section that opens upward, and a gap 90 is provided between the protrusion 80 and the side wall 72. Since there is a gap 90 between the projection 80 and the side wall portion 72, it is possible to suppress gravel, water, and the like from accumulating between the projection 80 and the projection 80.

  Further, according to the above embodiment, the lower case 70 is provided with the confirmation window 77 on the side wall 72 located outside the vehicle in the range W where the plurality of protrusions 80 are provided and above the protrusions 80. Provided. Thereby, since the periphery of the protrusion 80 in the chain case 50 can be easily visually confirmed from the confirmation window 77, it is possible to confirm the elongation of the chain 29 and to confirm whether gravel or the like is accumulated between the protrusion 80 and the protrusion 80. In addition, when the chain 29 is in contact with the protrusion 80, it is possible to confirm how the protrusion 80 is reduced due to the contact with the chain 29.

  Further, according to the above embodiment, since the protrusion 80 is formed integrally with the lower case 70 so as to extend inward from the inner surfaces of the bottom wall portion 71 and the side wall portion 73 of the lower case 70, A fastener or the like for attaching the protrusion 80 to the lower case 70 becomes unnecessary, and the number of parts can be reduced.

  In addition, according to the above-described embodiment, the lower case 70 has a U-shaped cross section that opens upward, and the protrusions 80 stand vertically in the vertical direction. Becomes easier. Further, since the hitting sound between the chain 29 and the protrusion 80 is used as a hitting sound, even if the chain case 50 is made of resin, it is possible to notify the passenger of the extension of the chain 29.

However, the above embodiment is an aspect of the present invention, and it is needless to say that the embodiment can be appropriately changed without departing from the gist of the present invention.
For example, in the above embodiment, the gap 90 is provided between the left side portion 81 of the protrusion 80 and the side wall portion 72 located on the vehicle outer side. However, the present invention is not limited to this, and the left side of the protrusion 80 The part 81 may be integrated with the inner surface of the side wall part 72, and a gap may be provided between the right side part 82 and the side wall part 73 located on the vehicle inner side.

Further, as shown in FIG. 8, the projection 180 has a front surface (surface) 180A and a rear surface (surface) 180B orthogonal to the vehicle front-rear direction and is formed in a thin plate shape, and only the lower portion 184 has a bottom wall portion. 71 may be provided so as to be integrated with the inner surface of 71. That is, the pair of left and right side portions 181 and 182 are spaced apart from the side wall 72,7 3, gaps 190 each is provided between the protrusion 180 and the side wall portions 72 and 73. As a result, the gaps 190 are provided on both the left and right sides of the protrusion 180, so that accumulation of gravel, water, and the like between the protrusion 180 and the protrusion 180 is further suppressed.

  Furthermore, as shown in FIG. 9, the protrusion 280 has a front surface (surface) 280A and a rear surface (surface) 280B orthogonal to the vehicle front-rear direction, and is formed in a thin plate shape. It is integrated with the inner surface of the side wall portion 72 located on the outer side, the right side portion 282 is integrated with the inner surface of the side wall portion 73 positioned on the vehicle inner side, and the lower portion 284 is separated from the bottom wall portion 71. May be provided. That is, the lower portion 284 is separated from the bottom wall portion 71, and a gap 290 is provided between the protrusion 280 and the bottom wall portion 71. Thereby, since the gap 290 is provided on the lower side of the protrusion 280, accumulation of gravel, water, or the like between the protrusion 280 and the protrusion 280 is suppressed.

1 is a side view showing a motorcycle to which a chain case according to the present invention is applied. FIG. 2 is a diagram showing the motorcycle of FIG. 1 with a body cover or the like removed. It is a disassembled perspective view of a swing arm and a chain case. It is a side view which shows an upper case. It is a side view which shows a lower case. It is a longitudinal cross-sectional view which shows a lower case. It is a side view which shows a chain case. It is a longitudinal cross-sectional view which is a modification of this invention and shows a lower case. It is a longitudinal cross-sectional view which is a modification of this invention and shows a lower case.

DESCRIPTION OF SYMBOLS 1 Motorcycle 2 Body frame 15 Rear wheel 20 Engine 27 Drive sprocket 28 Driven sprocket 29 Chain 40 Swing arm 50 Chain case 60 Upper case 70 Lower case 71 Bottom wall part 72, 73 Side wall part 77 Check window 80, 180, 280 Projection 83 Top (top)
80A, 180A, 280A Front (surface)
80B, 180B, 280B Rear surface (surface)
90, 190, 290 Gap W range A direction

Claims (6)

An engine supported by a vehicle body frame, and a swing arm whose front end is swingably supported by the vehicle body frame and rotatably supports a rear wheel at the rear end, the engine side drive sprocket and the rear wheel side A chain is spanned between the driven sprocket and a chain case having an upper case that covers the chain passing above the swing arm and a lower case that covers the chain passing below the swing arm is supported by the swing arm. In the chain case of motorcycles,
A plate-like protrusion is provided at the lower part of the inner surface of the lower case so that the chain has a surface that crosses the direction in which the chain moves and the chain and the upper end of the surface come into contact when the chain extends beyond a predetermined amount. Motorcycle chain case characterized by that.   The chain case for a motorcycle according to claim 1, wherein a plurality of the protrusions are provided at a distance from a lower portion of the inner surface of the lower case. The lower case includes a bottom wall portion extending in the vehicle front-rear direction and a pair of left and right side wall portions extending from the bottom wall portion toward the swing arm, and has a U-shaped cross section that opens upwardly.
The motorcycle chain case according to claim 1 or 2, wherein a gap is provided between the protrusion and at least one of the bottom wall portion and the pair of left and right side wall portions.   The said lower case is provided with the confirmation window in the said side wall part located in the vehicle outer side in the range where the said some protrusion is provided, and the position above the said protrusion. Motorcycle chain case.   The said protrusion is integrally formed with the said lower case so that it may extend inward from the inner surface of the bottom wall part of the said lower case, or the said left-right paired side wall part, or Claim 3 characterized by the above-mentioned. 4. A motorcycle chain case according to 4. The protrusion is provided on the lower case so as to stand vertically in the vertical direction,
The chain case for a motorcycle according to claim 3, wherein the chain case is made of resin.

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