A selected illustrative embodiment of the invention will now be described in some detail, with reference to the drawings. Note that, in the following, the drawings are viewed in the same direction as numerals. It should be understood that only structures considered necessary for clarifying the present invention are described herein. Other conventional structures, and those of ancillary and auxiliary components of the system, are assumed to be known and understood by those skilled in the art.
First, as shown in
On the left-side surface of the crankcase 11, an output shaft 16 of the transmission (not shown) is mounted so as to projecting from the crankcase 11, and a drive sprocket wheel 17, which is part of the drive force transmission mechanism, is connected to the output shaft 16. Further, a drive chain 17a, which is also part of the drive force transmission mechanism, is wound around the drive sprocket wheel 17.
The cooling device 20 includes: a water pump 21 arranged below the drive sprocket wheel 17 of the crankcase 11, an oil cooler 22 arranged on a front end surface of the crankcase 11, a thermostat valve 23 arranged on an upper end portion of the crankcase 11, a water jacket (not shown) formed in the inside of the cylinder block 12 and the cylinder head 13, and a radiator (not shown) arranged in front of the internal combustion engine 10. The water pump 21, the oil cooler 22, the thermostat valve 23, the water jacket (not shown), and the radiator (not shown) are in communication with each other by way of respective coolant pipes 24, 25, 26, 27. The coolant pipes 24, 25, 26 and 27 may be made from rubber, reinforced elastomeric tubing, or similar material.
In the internal combustion engine 10 of the depicted embodiment, the water pump 21 of the cooling device 20 is arranged below the drive sprocket wheel 17, thereby shortening the distance between the crankshaft 11a and the output shaft 16 as compared to a conventional internal combustion engine.
Further, in the depicted embodiment, as shown in
The outer cover 32 and the inner cover 31 cooperate to define a predetermined distance therebetween. This predetermined distance between the inner cover 31 and the outer cover 32 allows for the coolant pipes 24, 25 of the cooling device 20 to vertically pass through the space defined between the inner cover 31 and the outer cover 32. By passing the coolant pipes 24, 25 through the space defined by the inner cover 31 and the outer cover 32, the coolant pipes 24, 25 are protectively covered by the outer cover 32.
As shown in
Two fitting projections 34 are formed on an outer surface of the inner cover 31. Mounting holes 34a are formed in outer end surfaces of the fitting projections 34. Rubber or elastomeric grommets 35, having fitting holes 35a therein to receive projections 37 of the outer cover 32 (described below), are inserted into the fitting projections 34. Reinforcing ribs 36 are also cast in to the inner cover 31, to increase the strength and rigidity thereof.
As shown in
As shown in
On a lower end portion of the outer cover 32, an inclined portion 32a is inwardly and downwardly inclined is formed. The inclined portion 32a is provided with a guide portion 38, which guides a large-diameter breather hose 18 (a hose having one end portion thereof exposed to the outside air) and a small-diameter breather hose 19 (a hose having one end thereof exposed to the outside air), and an opening 39. The opening 29 is in communication with the guide portion 38. The guide portion 38 arranges the large-diameter breather hose 18 above the opening 39 and arranges the small-diameter hose 19 below the opening 39 in parallel (see
In the cover structure 30 of the internal combustion engine 10 having the above-mentioned formation, by inserting the projections 37 of the outer cover 32 into the fitting holes 35a formed in the grommets 35 of the inner cover 31 and the generator cover 15, the outer cover 32 is mounted on the inner cover 31 and the generator cover 15, and is arranged outside the inner cover 31. Accordingly, a space is formed between the inner cover 31 and the outer cover 32. By allowing the coolant pipes 24, 25 to pass through the space, the coolant pipes 24, 25 are protectively covered by the outer cover 32. Further, the rubber or elastomeric grommets 35 are arranged between the inner cover 31 and the outer cover 32 and between the generator cover 15 and the outer cover 32 and hence, vibrations of the respective covers 15, 31, 32 can be reduced.
As explained above, according to the cover structure 30 of the internal combustion engine 10 of the depicted embodiment, the outer cover 32 is arranged outside the inner cover 31, and the coolant pipes 24, 25 of the cooling device 20 are made to pass through the space defined between the inner cover 31 and the outer cover 32. According to such an arrangement, even when the internal combustion engine 10 is an internal combustion engine in which the distance between the crankshaft 11a and the output shaft 16 is shortened, it is possible to cover and protect the coolant pipes 24, 25 of the cooling device 20 of the internal combustion engine 10. Further, the coolant pipes 24, 25 are protectively covered by the coolant pipe cover, thereby enhancing the appearance of the internal combustion engine 10. Still further, by using two different covers, e.g. the outer cover 32 and the inner cover 31, it is possible to reduce radiation sounds of the internal combustion engine 10 thereby enhancing the tranquility of the internal combustion engine 10. Moreover, by arranging the coolant pipes 24, 25 outside of the drive sprocket wheel 17, the radiation sounds of the internal combustion engine 10 can be further reduced.
Further, according to the cover structure 30 of the internal combustion engine 10 of the depicted embodiment, the outer cover 32 is mounted on the inner cover 31 and the internal combustion engine 10 by inserting the outer cover 32 into the fitting holes 35a formed in the inner cover 31 thereby making it easier to assemble the cover structure 30. Additionally, since the outer cover 32 is mounted on the inner cover 31 such that the outer cover 32 is astride to the inner cover 31, the cooling pipe cover 32 is more firmly mounted on the inner cover 31. Also, by the depicted embodiment, a load which is applied to the inner cover 31 can be reduced thereby reducing the weight of the inner cover 31 while ensuring the rigidity of the inner cover 31.
According to the cover structure 30 of the internal combustion engine 10 of the depicted embodiment, the lower end portion of the outer cover 32 is provided with the guide portion 38, which guides the hoses 18, 19, each having one end portion exposed to the outside air, and the opening 39, which is in communication with the guide portion 38, it is unnecessary to additionally fix the hoses 18, 19 using a clamp or the like thereby reducing the number of parts. Further, the opening 39 is formed in the inclined portion 32a of the outer cover 32 and thereby making the opening 39 inconspicuous from the outside. Still further, the guide portion 38 allows the large-diameter hose 18 to be arranged above the opening 39 and the small-diameter hose 19 to be arranged below the opening 39 thereby preventing the small-diameter hose 19 from being exposed to the outside when viewed in a side view and enhancing appearance of the internal combustion engine 10.
While a working example of the present invention has been described above, the present invention is not limited to the working example described above, but various design alterations may be carried out without departing from the present invention as set forth in the claims.
Number | Date | Country | Kind |
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2006-230952 | Aug 2006 | JP | national |