Patent Grant
7694597
The present invention claims priority under 35 USC 119 based on Japanese patent application No. 2006-146731, filed on May 26, 2006. The subject matter of this priority document is incorporated by reference herein.
1. Field of the Invention
The present invention relates to a vehicle power unit, the power unit including an internal combustion engine and a transmission, the transmission modifying the rotational speed of the engine and transmitting the rotational driving force of the engine to vehicle wheels.
2. Description of the Background Art
In a known a vehicle power unit, which includes an internal combustion engine and a transmission, the transmission is configured to include input and output shafts disposed parallel to each other, and to further include a plurality of gear trains arranged between the input and output shafts. Such a power unit is disclosed, for example, in Japanese Patent Laid-Open No. 2002-227939. In the known vehicle power unit, lubricating oil is fed to sliding portions such as shafts and gears in order to stably operate an internal combustion engine and a power transmission device. A power unit case, which provides a housing for the internal combustion engine and the power transmission device, is formed with an oil storage portion adapted to collect the lubricating oil, which is fed under pressure to various portions by a feed pump.
The power transmission device of Japanese Patent Laid-Open No. 2002-227939 transmits rotation of a crankshaft to a main shaft, and the rotation of the main shaft to a countershaft in order to set a forward stage, or to an idle shaft for setting a reverse stage. Thus, the rotation of either the counter shaft or idle shaft is transmitted to an output shaft. These shafts are rotated and are provided with gears thereon; therefore, lubricating oil is fed to the shafts and to the gears. The lubricating oil fed to the shafts collects on the bottom of an inner space housed in a gear case housing the power transmission device.
However, the output shaft in the power transmission device of Japanese Patent Laid-Open No. 2002-227939 is disposed below a line connecting the respective shaft centers of the counter shaft and the idle shaft. Therefore, gearwheels carried on a shaft whose height from the oil storage portion is small are met with great stirring resistance, which may possibly lead to deterioration in power transmission efficiency.
In view of such a problem, an object of the present invention is to provide a power transmission device for a vehicle configured to quickly return lubricating oil which has been fed to the power transmission device to an oil storage portion.
To achieve the above object, a power unit for a vehicle according to the present invention includes a power unit case adapted to house an internal combustion engine, and at least part of a transmission for transmitting rotation of a crankshaft to vehicle wheels. The power unit case is formed with an oil storage portion adapted to collect lubricating oil in an inner lower side thereof. In addition, a gear chamber is supported by the crankcase. The lubricating oil fed to the gear chamber is discharged through a communicating port to the inside of the crankcase, and is returned to the oil storage portion. The communicating port is formed in one side face of the crankcase and permits the gear chamber to communicate with a crank chamber. The transmission includes an input shaft, an intermediate shaft and an output shaft which are housed in the gear chamber, and further includes gear trains executing power transmission among the input shaft, the intermediate shaft and the output shaft. The input shaft and the output shaft are arranged so that a line connecting respective shaft centers extends almost horizontally when the power unit is installed in a vehicle. The intermediate shaft is disposed above and between the input shaft and the output shaft, and the communicating port is disposed below the intermediate shaft.
In the illustrative embodiment, the communicating port is positioned adjacent to a wall surface extending downward toward the oil storage portion. The communicating port is disposed adjacent to a bottom surface of the gear chamber, and is formed inside a gear case attached to cover a portion of one side face of the crankcase. The input shaft receives rotation of crankshaft that has been changed in speed and the output shaft is a driving shaft of a transmission mechanism transmitting rotation to the wheels. Among gears constituting the gear trains, at least a drive gear provided on the input shaft and an idle gear provided on the intermediate shaft to mesh with the drive gear are housed in the gear chamber.
In the power unit of a vehicle configured described above, the input shaft and the output shaft constituting part of the transmission are disposed at almost the same height in the gear chamber, and the intermediate shaft is disposed above the input and output shafts. The communicating port provided on the bottom portion of the gear chamber is set at a high position. Thus, an increased difference in height between the communicating port and the oil storage portion is ensured. The lubricating oil in the gear chamber is quickly discharged to the oil storage portion and the possibility that the lubricating oil is returned from the oil storage portion to the gear case through the communicating port is reduced. In addition, since the communicating port is located below the intermediate shaft disposed between the input and output shafts, it is easy to discharge the lubricating oil through the communicating port even if the oil level becomes inclined, as occurs when the vehicle is operated on a hill.
Since the communicating port is located close to the wall surface extending downward toward the oil storage portion, the lubricating oil discharged from the gear chamber through the communicating port is returned to the storage portion while running along the wall surface. Thus, even if the increased difference in height between the communicating port and the oil storage chamber is ensured, the lubricating oil discharged through the lubricating port will not directly drop in the oil storage portion, whereby generation of foam the lubricating oil stored in the oil storage portion is avoided. As a result, the possibility that an oil pump produces air lock is reduced.
Since the communicating port is disposed adjacent to the bottom surface of the gear chamber, the level of the lubricating oil stored inside the gear chamber is lowered. The amount of the lubricating oil discharged to the oil storage portion is increased and the stirring resistance of the gear train housed in the gear chamber is reduced.
Among gears which constitute the gear trains, the drive gear and the idle gear meshing with the drive gear are housed in the gear chamber. When the gear case is removed, both the drive gear and the idle gear are exposed to the outside of one side face of the crankcase, and therefore can be each removed and replaced with another. Thus, the ability to provide maintenance for the gear train is enhanced and the reduction ratio of the power transmission device is easily changed only by changing the gear ratio between the drive gear and idle gear when the gears are each removed and replaced with another. Similarly, when the gear case is removed, the communicating port formed in one side face of the crankcase is exposed. Thus, the maintenance for the peripherals of the communicating port is also easily performed.
Modes for carrying out the present invention are explained below by reference to an embodiment of the present invention shown in the attached drawings. The above-mentioned object, other objects, characteristics and advantages of the present invention will become apparent form the detailed description of the embodiment of the invention presented below in conjunction with the attached drawings.
a) is a bottom view of the strainer used in the power unit of
b) is a side view of the strainer of
c) is a sectional view of the strainer taken along line C-C of
Selected illustrative embodiments of the invention will now be described in some detail, with reference to the drawings. 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. In the figures, arrows U and F denote the upper side and front, respectively, and references to left and right directions are made with respect to the front.
The power unit P is composed of a single-cylinder, four-stroke engine E and a power transmission M which transmits rotational driving force of the engine E to rear wheels (not shown).
Referring to
A combustion chamber 22 is defined by the cylinder head 2, the sleeve 12 and the piston 41. The combustion chamber 22 communicates with an intake port 31 and an exhaust port 32 formed inside the cylinder head 2, through an intake opening 33 and an exhaust opening 34, respectively. An intake valve 46 and an exhaust valve 47 attached to the cylinder head 2 are biased in directions of closing the intake and exhaust openings 33 and 34 by valve springs 46a and 47a, respectively. A cam shaft 51 is provided on its outer circumferential face with cams 53, 54, and is rotatably supported between confronting surfaces of the head cover 1 and the cylinder head 2. Rocker arms 55, 56 are pivotably provided inside the head cover 1 in such a manner that one ends of the rocker arms 55 and 56 are abutted against the cams 53 and 54, respectively, of the cam shaft 51 and the other ends of the rocker arms 55 and 56 are abutted against the upper ends of the intake and exhaust valves 46 and 47, respectively. Rotation of the crankshaft 42 is transmitted to the cam shaft 51 through chain transmission. When the cam shaft 51 is rotated, the rocker arms 55 and 56 are pivoted at predetermined times through the action of the cams 53 and 54, respectively. Thus, the intake and exhaust valves 46 and 47 are moved downward against the biasing force of the valve springs 46a and 47a to thereby open the intake and exhaust openings 33 and 34, respectively.
An intake pipe, not shown, communicating with the outside is connected to the intake port 31. A throttle valve for adjusting an intake volume, an injector for injecting fuel and an air cleaner for purifying outside air are attached to the intake pipe. When the piston 41 moves downward, the air purified by the air cleaner is mixed with fuel injected by the injector. The air-fuel mixture of the amount according to the opening angle of the throttle valve is fed to the combustion chamber 22 from the intake port 31 via the intake opening 33. The air-fuel mixture is compressed as the piston 41 moves upward and then ignited for combustion by an ignition plug, not shown, attached to the cylinder head 2, which again moves the piston 41 downward. When the piston 41 again moves upward, the exhaust gas is discharged to the outside through the exhaust opening 34, the exhaust port 32 and an exhaust pipe, not shown, connected to the exhaust port 32. While the series of strokes of intake, compression, combustion and exhaust are repeated, the piston 41 is reciprocated to rotate the crankshaft 42.
The crankcase 4 is split into a right-half section and a left-half section, namely, a right case 5 and a left case 6, which are connected to each other. A right cover 9 is attached to cover part of the right side surface of the right case 5. A left cover 10 is attached to cover the front portion of the left side surface of the left case 6.
A right end portion 42a of the crankshaft 42 is received in the inside (a right auxiliary machinery chamber 25) of the right cover 9. A cam drive sprocket 52a and a primary drive gear 111 of the transmission M constitute a chain transmission mechanism for transmitting power to the cam shaft 51, and are connected to the right end portion 42a of the crankshaft 42. A drive shaft 83 of an oil pump (a feed pump 81 and a scavenging pump 82) is coupled to the right end of the crankshaft 42. A left end portion 42b of the crankshaft 42 is received in the inside (a left auxiliary machinery chamber 26) of the left cover 10. A generator 86 is provided on the left end portion 42b. In addition, a starter driven gear 78 adapted to start the crankshaft 42 via a one way clutch 79 is connected to the left end portion 42b. The rotational drive force of a starter motor 71 is transmitted to the starter driven gear 78. The starter motor 71 is attached to a motor attachment bracket 6a integrally extending upward from the left case 6.
As shown in
As shown in
As shown in
As shown in
As shown in
The speed change gear train includes first to fifth speed gear trains G1 to G5 for setting a forward stage as shown in
The speed change mechanism 120 shown in
Referring to
The final gear train 170 includes a final drive gear 171, a final idle gear 172 and a final driven gear 173. The final drive gear 171 is provided at the left end portion 103b of the counter shaft 103. The final idle gear 172 is provided on the final idle shaft 104 so as to mesh with the final drive gear 171. The final driven gear 173 is provided on the output shaft 105 so as to mesh with the final idle gear 172. As shown in
With such a transmission M, rotation of the crankshaft 42 is transmitted to the main shaft 101 via the primary gear train 110 and the main clutch 115. The rotation of the main shaft 101 is transmitted to the counter shaft 103 via any one of the speed change gear trains. The rotation of the counter shaft 103 is transmitted to the output shaft 105 via the final gear train 170. The rotation of the output shaft 105 is finally transmitted to the rear wheel via the chain drive mechanism 175.
The speed change mechanism 120 is now described with reference to
The dog clutch mechanism 135 shown in
The shift change mechanism 140 is shown in
The shift spindle 141, the shift drum 142 and the fork shaft 146 are each supported at both ends thereof by the transmission case 8 and received in the lower portion of the transmission chamber 28. The shift spindle 141 and the shift drum 142 are rotatably supported whereas the fork shaft 146 is fixed to the transmission case 8. Aright end 141a of the shift spindle 141 is received in the right auxiliary machinery chamber 25 and is connected to the interlocking mechanism 150. The shift fork 143 has a distal end 143a engaged with the fork groove 136c of the first shift sleeve 136 and a proximal end 143b engaged with the first cam groove 142a. The second shift fork 144 has a distal end 144a engaged with the fork groove 137c of the second shift sleeve 137 and a proximal end 144b engaged with the second cam groove 142b. The third shift fork 145 has a distal end 145a engaged with the fork groove 138c of the third shift fork 138 and a proximal end 145b engaged with the third cam groove 142c.
With the dog clutch mechanism 135 and the shift change mechanism 140 configured as described above, the shift spindle 141 is rotated in response to the operation of the shift pedal. Since the shift spindle 141 is interlocked with the rotation the shift drum 142, the shift drum 142 is rotated in a predetermined rotational direction by a predetermined angle in time with the shift spindle 141. Thus, the first, second and third shift fork 143, 144 and 145 are guided by the cam grooves 142a, 142b and 142c, respectively, to move in the axial direction of the fork shaft 146. Movement of each of the shift forks 143, 144 and 145 axially moves a corresponding one of the shift sleeves 136, 137 and 138 on a corresponding one of the main shaft 101 and the counter shaft 102. In this way, the speed change stage according to the shift pedal operation is set as described further below.
When all of the first, second and third sleeves 136, 137 and 138 are placed at their respective neutral positions, a neutral stage is established in which power transmission from the main shaft 101 to the counter shaft 103 is interrupted. When the shift pedal is operated from the neutral state to shift gears to the upshift side, the shift drum 142 is rotated in a direction of arrow R1 at a predetermined angle to move the second shift sleeve 137 rightward. This causes the first speed driven gear 126 to be integrally rotatable with the countershaft 103, thereby establishing a first speed stage in which power transmission is executed through the first speed gear train G1. With a repeat of the same operation, the third shift sleeve 138 is moved leftward to cause the second speed driven gear 127 to be integrally rotatable with the counter shaft 103, thereby establishing a second speed stage in which power transmission is executed through the second speed gear train G2. The third shift sleeve 138 is moved rightward to cause the third speed driven gear 128 to be integrally rotatable with the counter shaft 103, thereby establishing a third speed stage in which power transmission is executed through the third speed gear train G3. The first shift sleeve 136 is moved rightward to cause the fourth speed drive gear 124 to be integrally rotatable with the main shaft 101, thereby establishing a fourth speed stage in which power transmission is executed through the fourth speed gear train G4. The first shift sleeve 136 is moved leftward to cause the fifth speed drive gear 125 to be integrally rotatable with the main shaft 101, thereby establishing a fifth speed stage in which power transmission is executed through the fifth speed gear train G5.
When a reverse arm (not shown) attached to the handlebar of the vehicle is operated, an inhibitor mechanism 160 shown in
In the establishment of the speed change stages discussed above, of the three shift sleeves, the two shift sleeves which are omitted from the explanation are returned to or maintain their respective neutral positions. For example, during establishment of engagement of the first speed gear train, the second shift sleeve 137 moves rightward to cause the first speed driven gear 126 to be integrally rotatable with the countershaft 103, while the first shift sleeve 136 and third shift sleeve 138 maintain their respective neutral positions.
As shown in
The shift drum 142 is formed on its outer circumferential face with an inhibitor groove 142d extending in the circumferential direction. A stopper 142g is formed in the inhibitor groove 142d so as to project radially outwardly. The inhibitor arm 162 is biased by the torsional coil spring 163 so that its leading end 162b is located inside the inhibitor groove 142d.
The inhibitor shaft 161 is a stepped shaft formed such that its right and left end sections 161a, 161b are larger in diameter than its central section 161c. The left end portion 161b of the inhibitor shaft 161 is inserted into a through-hole formed in the proximal end 162a of the inhibitor arm 162. The right end surface of the inhibitor arm 162 is abutted against and welded to the left end face of the central section 161c, so that the inhibitor arm 162 is integrally rotatable with the inhibitor shaft 161. The central section 161c of the inhibitor shaft 161 is carried by the right cover 9, the left end section 161b is carried by the right side surface of the right case 5, and the right end section 161a is exposed to the outside of a housing H described later.
A coil section 163a of the torsional coil spring 163 is wound around the central section 161c of the inhibitor shaft 161, which is received in the right auxiliary machinery chamber 25. One end portion 163b of the torsional coil spring 163 extends from one side of the coil section 163a of the torsional coil spring 163, and is retained between the right case 5 and a strainer 85 described later. The other end portion 163c of the torsional coil spring 163 extends from the other side of the coil section 163a, and is retained by a retaining groove 162c of the inhibitor arm 162. Both the end portions 163b, 163c are retained in this way, whereby the leading end 162b of the inhibitor arm 162 is biased against the inhibitor groove 142d. In this case, the inhibitor arm 162 abuts against a stopper portion 5u projecting from the inner wall face of the right case (see
As shown in
In the reverse inhibitor mechanism 160, the leading end 162b of the inhibitor arm 162 is located inside the inhibitor groove 142d when the reverse lever is not operated so that the reverse change arm 164 is located at a normal position. For this reason, even if the shift drum 142 is about to rotate in the direction of establishing the reverse stage, the leading end 162b of the inhibitor arm 162 abuts against the stopper 142g formed inside the inhibitor groove 142d so as to restrict the rotation of the shift drum 142. When the reverse lever is operated, the reverse change arm 164 is pivotally moved. Since the reverse change arm 164 is fastened to the right end section 161a of the inhibitor shaft 161, the pivotal movement of the reverse change arm 164 reliably turns the inhibitor shaft 161. When the inhibitor shaft 161 is rotated in conjunction with the reverse change arm 164, the inhibitor arm 162 is pivotally moved in the direction of arrow R2 in
A description of the housing structure of the power unit P will be now described with additional reference to
An oil storage chamber 35 is formed within the housing H below the transmission chamber 28. The line OL shown in
The right cover 9 is fastened to a cover mounting rib 5h formed to project from the right side surface of the right case 5 as shown in
A lubricating oil system of the power unit P is hereinafter described with reference to
Referring to
Referring to
The core 85b is formed integrally with a flat plate-like attachment bracket 85d which extends from one side of the rectangular frame in a direction normal to the plane in which the filter element 85a lies, that is, in a vertical direction relative to a direction of holding the filter element 85a. The attachment bracket 85d is formed with an circular hole 85e passing therethrough at a position above the central portion of the attachment bracket 85d. As shown in
Referring to
With the strainer 85 fastened to the right case 5, the retaining portion 85f, formed on the attachment bracket 85d, projects upward from the upper wall portion 5s to face the shift change mechanism 140 and the reverse inhibitor mechanism 160. The retaining portion 85f and the right case 5 are designed to retain the one end portion 163b of the torsional coil spring 163 which, as described above, is included in the reverse inhibitor mechanism 160. An elongate portion 163f is formed so as to bend from the one end portion 163b of the torsional coil spring 163 and extend linearly therefrom. As shown in
A description is now provided of the lubricating oil passages formed inside the main shaft 101, the reverse idle shaft 102 and the counter shaft 103 among the lubricating oil passages as well as of the supporting structures for the shafts 101, 102 and 103, with reference to
Referring to
Referring to
Referring to
The reverse idle shaft 102 has a right end 102a which is press fitted into a hole formed in the left side face of the right case 5 and a left end 102b which press fitted into a hole formed in the right side face of the left case 6. Thus, the axial oil passage 102c communicates, through a right end opening 102d, with an oil sump 227 formed inside the hole into which the right end 102a is press fitted. Similarly, the axial oil passage 102c communicates, through a left end opening 102e, with an oil sump 226 formed inside the hole into which the left end 102b is press fitted. The left case 6 is formed in its right side face with a retaining groove 6q extending radially outwardly from the hole into which the left end 102b of the reverse idle shaft 102 is press fitted. When the left end 102b of the reverse idle shaft 102 is press fitted into the left case 6, the tip portion 182a of the pin 182 is fitted into the retaining groove 6q. In this way, the reverse idle shaft 102 is attached so as to be circumferentially positioned (fixed) with respect to the transmission case 8.
By fixing the position of the reverse idle shaft 102 with respect to the transmission case, it is ensured that the first jet oil passage 102f faces the meshing portion of the fifth speed gear train G5 and the second jet oil passage 102g faces the meshing portion of the fourth speed gear train G4. In addition, the reverse idle gear shaft 102 is located above and between the main shaft 101 and the counter shaft 103 in the front-to-rear direction. Therefore, the respective openings of the first and the second jet oil passage 102f, 102g face substantially downward.
The reverse idle shaft 102 is subjected to cutting work to be accurately form the through-hole 102h of circular in cross-section therein, while the pin is provided with increased dimensional accuracy. The pin 182 is press fitted into the through-hole 102h such that backlash (chattering) is prevented, while the backlash between the pin 182 and the retaining groove 6q is reduced. Thus, the reverse idle shaft 102 can be accurately circumferentially, and also axially, positioned with respect to the transmission case 8. In addition, the openings of the first and second jet oil passages 102f, 102g can be oriented toward the respective targeted directions.
As shown in
The right end 103a of the counter shaft 103 is supported by a bearing 183 received in a receiving hole 5p formed in the right case 5. In this instance, the right end of face of the counter shaft 103 is formed flush with the right end face of the bearing 183. The receiving hole 5p is formed as a stepped circular cylinder and the diameter of the cylindrical hole is smaller as it goes rightward. Thus, in the state where the bearing 183 is received in the receiving hole 5p and the counter shaft 103 is supported, an oil sump 229 is formed on the right side of the bearing 183 inside the receiving hole 5p so as to communicate with the axial oil passage 103c via a right end opening 103e.
The fork shaft 146 shown in
The lubricating oil passages formed inside the housing H will now be described. As shown in
The oil passage 212 communicates at its front upper end with an oil passage 213 which extends inside the right case 5 in the left-and-right direction. The oil passage 213 communicates with a bolt insertion hole, which is formed in the circumferential edge of a fitting hole 4a used to connect the cylinder block 3 with the crankcase 4. In addition, the oil passage 213 communicates with the front end of an oil passage 214, which extends in the front-to-rear direction along the upper wall portion 5e inside the right case 5. The oil passage 214 communicates at its rear end with an oil passage 215 formed to extend in the left-and-right direction.
As shown in
Referring to
Referring to
With reference to
Referring to
In the power unit P having the lubricating oil passages described above, when the engine E is running, the crankshaft 42 rotates, and thus the pump drive shaft 83 is rotated to drive the rotors of the feed pump 81 and the scavenging pump 82. When the feed pump 81 is operated, the lubricating oil stored in the oil storage chamber 35 is allowed to flow in the oil passage 201, is drawn into the intake port 81a of the feed pump 81, and discharged from the discharge port 81b. The lubricating oil discharged from the discharge port 81b is filtered by the oil filter 210 and directed from the inside of the right cover 9 to the inside of the right case 5 via the oil passage 212. The lubricating oil is further directed through the oil passages 215, 216 to the inside of the left case 6. The lubricating oil fed to the oil passage 218 is fed through the oil sump 226 to the axial oil passage 102c of the reverse idle shaft 102. The lubricating oil is further fed through the oil sump 219 to the axial oil passage 101c of the main shaft 101 and to the oil passage 220.
As shown in
The lubricating oil directed to the axial oil passage 102c of the reverse idle shaft 102 is fed through the oil sump 227 to the oil passage 228 and then through the oil sump 229 to the axial oil passage 103c of the counter shaft 103. The lubricating oil fed to the axial oil passage 103c of the counter shaft 103 is fed through the radial oil passages 103d to the joining portion between the counter shaft 103 and each of the first speed driven gear 126, the reverse driven gear 133, the third speed driven gear 128, the third shift sleeve 138, the fifth speed driven gear 130 and the second speed driven gear 127. The lubricating oil thus fed to the joining portions is discharged inside the transmission chamber 28.
Referring to
Referring to
As shown in
The lubricating oil discharged in the crank chamber 24 is returned to the oil storage chamber 35 via the communication space 4b located below the front lower portion of the crank chamber 24. At this time, the lubricating oil discharged in the crank chamber 24 is circumferentially raked out by the rotating crank webs 42c, 42c. The central partition walls 5g and 6g include oil collecting ribs 5j and 6j, respectively formed at their lower ends, which are designed to collect the lubricating oil raked out and circumferentially splashed by the crank webs 42c, 42c. The lubricating oil thus collected is effectively returned to the oil storage chamber 35 via the communication space 4b.
Referring to
The lubricating oil discharged in the final gear chamber 29 through the final gear chamber supply oil passage 103f is jettedly supplied to the final drive gear 171 and the final idle gear 172. An internal rear lower portion 29a of the final gear chamber 29 is downwardly concave so as to extend along the outer profile of the final driven gear 173. A portion of the lubricating oil that is discharged in the final gear chamber 29 reaches the recession of the rear lower portion 29a, and is raked up by the final driven gear 173, lubricating the final gear train 170.
Referring to
As described above, in the configuration of the embodiment, the reverse idle shaft 102 constituting part of the transmission M is formed with the axial passage 102c, and the first and the second jet oil passage 102f, 102g. Both the ends 102a, 102b of the reverse idle shaft 102 are supported by the half-split transmission case 8. The axial oil passage 102c is allowed to communicate with the oil passages 218 and 228 (the oil sumps 226 and 227) formed inside the right case 5 and the left case 6, respectively. The respective openings of the first and the second jet oil passage 102f, 102g is made to face the respective meshing portions of the fourth and the fifth speed gear trains G4 and G5 among the forward stage setting gear trains provided between the main shaft 101 and the counter shaft 103.
Thus, the lubricating oil is sprayed from the reverse idle shaft 102 to the meshing portions of the gear trains constituting the transmission M, which makes it possible to effectively lubricate the speed change gear trains. The member forming the oil passage adapted to lead lubricating oil from the inner oil passage of one of the case halves to the inner oil passage of the other, and the member adapted to spray the lubricating oil to the speed change gear trains are not dedicated members but are provided within the shafts of the transmission M. Therefore, the transmission M and the lubricating device, both of which have the above effects is configured while reducing the number of component parts.
The pin 182 is attached to the end of the reverse idle shaft 102 in such a manner that its tip portion 182a projects radially outward beyond a periphery of the reverse idle shaft 102. When the reverse idle shaft 102 is fastened to the transmission case 8, the tip portion 182a of the pin 182 is fitted into the retaining groove 6q formed in the inner surface of the transmission case 8. Thus, this simple configuration effectively restricts the rotation of the reverse idle shaft 102 relative to the transmission case 8. In addition, this configuration permits the reverse idle shaft 102 to be accurately circumferentially positioned with respect to the transmission case 8. Thus, the openings of the first and second jet oil passages 102f, 102g are surely oriented toward the respective targeted directions.
The left end opening 102e of the axial oil passage 102c of the reverse idle shaft 102 communicates with the oil passage 218 (and the oil sump 226) connected to the discharge port 81b of the feed pump 81. In addition, the right end opening 102d of the reverse idle shaft 102 communicates with the oil passage 228 (and the oil sump 227) connected to the right end opening 103e of the axial oil passage 103c of the counter shaft 103. Thus, the axial oil passage 102c of the reverse idle shaft 102 is located on the upstream side of lubrication oil flow, whereas the axial oil passage 103c of the counter shaft 103 is located on the downstream side. This makes it possible for higher pressurized lubricating oil to be sprayed on the meshing portions of the speed change gear trains. In addition, the lubricating oil reduced in pressure resulting from the jet spray is fed to the gears or the like provided on the counter shaft 103. In this way, the lubricating oil can be effectively fed according to the hydraulic pressure.
As shown in
The counter shaft 103 and the output shaft 105 are juxtaposed in the front-to-rear direction and the final idle shaft 104 is located above and between the counter shaft 103 and the output shaft 105 in the front-to-rear direction. In the embodiment, the counter shaft 103 and the output shaft 105 are located at respective positions higher than the crankshaft 42. The oil storage chamber 35 is formed to be located below the crank chamber 24 housing the crankshaft 42. Thus, a difference in height between the oil storage chamber 35 and the second communicating port 99, which allows the final gear chamber 29 to communicate with the transmission chamber 28, is increased. This increased difference in height enables the lubricating oil discharged in the final gear chamber 29 to be quickly discharged toward the oil storage chamber 35. In addition, the increased difference in height also reduces the possibility that the lubricating oil will be returned from the oil storage chamber 35 toward the final gear chamber 29. This reduces the amount of lubricating oil collecting in the final gear chamber 29, which reduces the stirring resistance of the final gear trains 170. Since the amount of the lubricating oil in the oil storage chamber 35 is stable, a disadvantage is eliminated whereby the feed pump 81 produces air lock. Since the second communicating port 99 is provided at a central portion in the front-to-rear direction of the final gear chamber 29, the vertical position of the second communicating port 99 is stable with respect to the level of the lubricating oil. Even if the level of the lubricating oil in the final gear chamber 29 is tilted in the front-to-rear direction due to traveling of the vehicle on a slope, it is easy to discharge the lubricating oil from the second communicating port 99.
The lubricating oil discharged in the final gear chamber 29 collects on the bottom at least at a height of the second communicating port 99 without being discharged therefrom. In this embodiment, since the second communicating port 99 is adjacent to the lower wall portion of the gear case attachment rib 6i, the minimum amount, per se, of lubricating oil collecting in the final gear chamber 29 is reduced, which stabilizes the amount of the lubricating oil in the oil storage chamber 35.
The second communicating port 99 is formed adjacently to the inner surface of the rear wall portion 6d of the left case 6, which extends forwardly and downwardly at an angle from the transmission chamber 28 toward the oil storage chamber 35, which is below the transmission chamber 28. The lubricating oil discharged through the communicating hole 99 to the transmission chamber 28 can be therefore returned to the oil storage chamber 35 while running along the inner surface of the rear wall portion 6d. Thus, even if the increased difference in height between the second communicating port 99 and the oil storage chamber 35 is ensured, the lubricating oil discharged in the transmission chamber 28 will not directly drop in the oil storage chamber 35 to otherwise foam the lubricating oil stored in the oil storage chamber 35. This can reduce the possibility that the feed pump 81 produces air lock.
When the gear case 11 is removed, the respective right ends of the counter shaft 103, the final idle shaft 104 and the output shaft 105 appear while being intactly retained on the side of the left case 6. The final gear train 170, together with the second communicating port 99, is exposed to the left side of the vehicle. Thus, the final gear train 170 is easily removed and replaced with another. Maintenance of the final gear train 170 and customization such as the change of the reduction ratio of the transmission M are easily performed. In addition, the maintenance of the peripherals of the second communicating port 99 is easily performed.
The strainer 85 is fitted into and attached to the receiving groove 5r formed in the right case 5 and then fastened to the right case 5. This will prevent the strainer 85 from dropping easily and make it easier to attach the strainer 85. The one end portion 163b of the torsional coil spring 163 constituting part of the reverse inhibitor mechanism 160 is retained by the retaining portion 85f formed integrally with the attachment bracket 85d of the strainer 85. In this way, since the strainer 85 is reliably fastened, the torsional coil spring 163 is also reliably fastened. In addition, it is not necessary to otherwise form a rib or groove in the inner surface of the housing H to retain the torsional coil spring as in the traditional way, which can enhance the manufacturability of the housing H.
The one end portion 163b of the torsional coil spring 163 is formed to include the linear portion 163d extending from the coil portion 163a and the bent portion 163e which bends at the tip of the linear portion 163d. Even if the retaining portion 85f of the attachment bracket 85d is formed like a flat plate, it is maintained that the one end portion 163b of the torsional coil spring 163 constantly abuts against the retaining portion 85f. The forming work of the attachment bracket 85d is simplified to enhance the manufacturability of the strainer 85. Further, the retaining portion 85f is formed to project from the filter element 85a. Therefore, the bent portion 163e of the torsional coil spring 163 and the like can be attached without interference with the strainer and others, which makes it possible to smoothly operate the reverse inhibitor mechanism 160.
In order to reduce the size of the reverse inhibitor mechanism 160 configured by retaining the torsional coil spring 163 at the strainer 85, it is necessary to bring the constituent members of the shift change mechanism 140, including the shift drum 142, close to the vicinity of the oil storage chamber 35. The shift change mechanism 140 is a mechanism for changing the setting of the speed change stage and is not a part of the power transmission path. Thus, the arrangement of the shift change mechanism 140 close to the oil storage chamber 35 does not influence the power transmission efficiency, so that the reverse inhibitor mechanism 160 may be reduced in size.
The strainer 85 is inserted for attachment from the right side into the receiving hole formed in the right case 5 and fastened to the right case 5 via a bolt inserted into the bolt insertion hole 5t opening in the right side face of the right case 5. The strainer 85, in the assembled state, is covered by the right cover 9. Thus, the strainer 85 can be easily removed and replaced with another only by removing the right cover 9, facilitating maintenance of the strainer 85.
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 |
|---|---|---|---|
| 2006-146731 | May 2006 | JP | national |
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|---|---|---|---|
| 4914968 | Diermeier et al. | Apr 1990 | A |
| 5025673 | Yamada | Jun 1991 | A |
| 6296073 | Rioux et al. | Oct 2001 | B1 |
| 6941918 | Laimboeck | Sep 2005 | B2 |
| 20060123944 | Suzuki et al. | Jun 2006 | A1 |
| Number | Date | Country |
|---|---|---|
| 58-195012 | Dec 1983 | JP |
| 10-119591 | May 1998 | JP |
| 2002-227939 | Aug 2002 | JP |
| 2003-239715 | Aug 2003 | JP |
| 2003-306191 | Oct 2003 | JP |
| 2004-036633 | Feb 2004 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20070295159 A1 | Dec 2007 | US |
