Internal-combustion engines – Starting device – Having specific mounting or drive connection for electric...
Reexamination Certificate
2000-03-03
2001-10-23
Argenbright, Tony M. (Department: 3747)
Internal-combustion engines
Starting device
Having specific mounting or drive connection for electric...
Reexamination Certificate
active
06305337
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an overhead cam shaft type engine for being installed on a vehicle such as a motorcycle, with a starter motor being attached to a surface of a crank case thereof.
2. Description of Related Art
An overhead cam shaft V-type engine mounted on a motorcycle and having a cam shaft provided in a cylinder head has been known, wherein a starter motor and an oil filter are attached respectively to a front face of a crank case and a front face of an oil pan (see Japanese Published Unexamined Patent Application No. Hei 10-141039).
The above conventional overhead cam type engine is mounted horizontally on a vehicle so that a crank shaft extends in the transverse direction. In the mounted state of the engine, a front cylinder of a front bank is inclined forward and a rear cylinder of a rear bank is inclined backward. A cylinder head is mounted to each of the front and rear cylinders, and an intake cam shaft and an exhaust cam shaft for actuating an intake valve and an exhaust valve through a valve operating mechanism are mounted in the cylinder head. Cam sprockets are mounted respectively on left end portions of the intake and exhaust cam shafts in the front cylinder. Furthermore, a cam shaft driving chain is stretched between the cam sprockets and a driving sprocket mounted on a left end portion of the crank shaft while being entrained on those sprockets, whereby the rotation of the crank shaft is transmitted to both of the cam shafts. Cam sprockets are also mounted on right end portions of the intake and exhaust cam shafts in the rear cylinder. Furthermore, a cam shaft driving chain is stretched between the cam sprockets and a driving sprocket mounted on a right end portion of the crank shaft while being entrained on those sprockets, whereby the rotation of the crank shaft is transmitted to both of the cam shafts.
On the left end portion of the crank shaft are mounted an AC generator and a starter driven gear which is positioned adjacent the AC generator. A starter motor is attached to the front face of the crank case. Upon start-up of the engine, the rotation of the starter motor is transmitted to the crank shaft via a gear train which comprises a pinion gear and a reduction gear and through the starter driven gear mounted on the crank shaft.
In the conventional art referred to above, since the driving sprocket, cam shaft driving chain and cam sprockets, which constitute the cam shaft driving mechanism in the front cylinder, the cam shaft driving mechanism and the gear train are provided on the left end portion of the crank shaft. In this case, since it is necessary to avoid interference of both the cam shaft driving mechanism and the gear train, it has so far been difficult to mount the starter motor at an upper position of the front face of the crank case. Therefore, in the conventional art being considered, it is inevitably required that an oil filter, which is also mounted in front of the engine like the starter motor, be attached to the front face of the oil pan mounted to a lower portion of the crank case. This restricts, for example, the arrangement of an exhaust pipe extending from the front cylinder.
SUMMARY OF THE INVENTION
The present invention has been accomplished in view of such circumstances, and it is an object of a first aspect of the present invention to eliminate interference of both the gear train and the cam shaft driving mechanism. Furthermore, it is an object of the first aspect of the present invention to mount the starter motor to the surface of the crank case while it is drawn as close as possible to the cylinder, thereby creating a space on the surface of the crank case.
According to a second aspect of the present invention, the first aspect of the present invention is applied to an engine, wherein a crank case has a dividing plane passing through a crank shaft axis.
According to a third aspect of the present invention, the first aspect of the present invention is applied to an engine, wherein a crank case is divided vertically by a dividing plane passing through a crank shaft axis to attain a compact size of the crank case.
According to a fourth aspect of the present invention, it is an object to increase the degree of freedom in the arrangement of components attached to the engine.
According to a fifth aspect of the present invention, it is an object to simplify the structure of an oil passage and reduce the size of an oil pan.
According to a sixth aspect of the present invention, it is an object to increase the degree of freedom in the arrangement of an exhaust pipe.
According to a seventh aspect of the present invention, it is an object to apply the first through sixth aspects of the present invention to a V-type 2-cylinder engine.
In the present case, the first aspect of the present invention is an overhead cam shaft type engine with a starter motor, comprising a cylinder, a cam shaft provided in a cylinder head mounted to the cylinder, a cam shaft driving mechanism disposed on one end side of the crank shaft to transmit the rotation of the crank shaft to the cam shaft, and a gear train disposed on an opposite end side of the crank shaft to transmit the rotation of the starter motor to the crank shaft, wherein the starter motor is attached to a surface of a crank case, a gear shaft axis of at least one of plural gears which constitute the gear train is disposed on a side of a plane including a crank shaft axis on which side a cylinder axis of the cylinder is positioned, and an included angle between a planar portion extending toward the gear train from the crank shaft axis in the above plane and the cylinder axis is an acute angle.
Thus, according to the first aspect of the present invention, the starter motor is attached to the surface of the crank case and an included angle between the planar portion extending toward the gear train and the cylinder axis is an acute angle. Therefore, despite the cylinder being positioned close to the starter motor, the gear train is disposed on the opposite end side of the crank shaft opposite to the one end side of the crank shaft where the cam shaft driving mechanism is disposed.
Therefore, without interference with the cam shaft driving mechanism, a gear shaft axis of at least one of plural gears which constitute the gear train can be disposed closer to the cylinder with respect to the aforesaid plane. As a result, it also becomes possible for the starter motor to be attached to the surface of the crank case at a position close to the cylinder, so that a space is created on the crank case surface, which space can be utilized for the mounting of components.
According to the second aspect of the present invention, an overhead cam shaft type engine with a starter motor is provided, wherein the crank case is divided into two crank cases by a dividing plane. The dividing plane, including the crank shaft axis, is the dividing plane. More specifically, the crank case is divided by the dividing plane into a crank case where a cylinder is provided and a crank case where a cylinder is not provided. A gear shaft axis of at least one of plural gears which constitute the gear train can be disposed in the crank case where a cylinder is provided. Consequently, in proximity to the surface of the crank case, the starter motor can be mounted to the surface of the crank case where a cylinder is not provided, or it can be mounted to the surface of the crank case where a cylinder is provided. As a result, it becomes possible to dispose the starter motor in proximity to the cylinder, thus permitting a space to be created on the surface of the crank case where a cylinder is not provided.
According to the third aspect of the present invention, an overhead cam shaft type engine with a starter motor is provided, wherein the crank case is divided vertically into an upper crank case and a lower crank case by a dividing plane. The crank shaft is supported by the upper crank case and the lower crank case, and the foregoing plane including the crank shaft axis is
Sawa Atsushi
Sumi Hiromi
Ali Hyder
Argenbright Tony M.
Honda Giken Kogyo Kabushiki Kaisha
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