192 clutches and power-stop control – Vortex-flow drive and clutch
Reexamination Certificate
1999-11-12
2001-12-04
Bonck, Rodney H. (Department: 3681)
192 clutches and power-stop control
Vortex-flow drive and clutch
C192S113500
Reexamination Certificate
active
06325190
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a transmitting system utilized in a small-sized vehicle such as a motorcycle, a four-wheel buggy and the like, and particularly, to an improvement in a transmitting system utilized in a small-sized vehicle, in which a crankshaft of an engine and an input shaft of a multi-stage transmission, which is disposed in parallel to the crankshaft, are leading to each other through a fluid transmitting means including a pump impeller leading to the engine, and a turbine impeller connected to the multi-stage transmission.
2. Description of the Related Art
There are such already known transmitting systems for small-sized vehicles, in which the fluid transmitting means is comprised of a torque converter, as disclosed in, for example, Japanese Patent Application Laid-open No. 57-69163.
In such known transmitting system, as described in the above Publication, the crankshaft of the engine and the input shaft of the multi-stage transmission are connected to each other only through the torque converter, so that a torque shock generated at the time of the starting the vehicle or during shifting is absorbed by a slipping action of the torque converter.
However, the known transmitting system suffers from the following drawbacks: The torque converter or the fluid coupling has a slipping function, but performs the transmission of a torque to certain degree, as long as a power is input from the engine to the torque converter or the fluid coupling. Therefore, in the known system, at the time of starting the vehicle in which the transmission is switched over from a neutral position to a low or first-speed position, a creep phenomenon is produced in which power is transmitted to a driving wheel of the vehicle to certain degree, even if the engine is in an idling state. During traveling of the vehicle, the friction always occurs in switching and sliding portions of the transmission due to the transmitted torque. For this reason, there are inconveniences that the resistance to the switching of the transmission is large, and a large shifting load is required. In addition, the torque converter is mounted to the input shaft of the multi-stage transmission driven in a decelerated manner from the engine and for this reason, the transmitted torque borne by the torque converter is relatively large, and hence, a large-sized torque converter having a large capacity is obliged to be used. This makes it difficult to provide the compactness of the power unit including the engine and the transmission.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a transmitting system of the above-described type for a small-sized vehicle, wherein the creep phenomenon is eliminated; the shifting operation of the transmission can be carried out lightly; the compactness of the power unit can be obtained; and a lubricating oil for the engine can be utilized effectively to operate the fluid transmitting means.
To achieve the above object, according to the present invention, there is provided a transmitting system for a small-sized vehicle in which a crankshaft of an engine and an input shaft of a multi-stage transmission, which is disposed in parallel to the crankshaft, are connected to each other through a fluid transmitting means including a pump impeller leading to the engine, and a turbine impeller leading to the multi-stage transmission, wherein the transmitting system includes a shifting clutch, the fluid transmitting means and the shifting clutch being mounted on the crankshaft of the engine and connected in series to each other, one of the fluid transmitting means and the shifting clutch being connected to the crankshaft, and the other being connected to the input shaft of the multi-stage transmission through a primary reducing device; and the crankshaft is provided with an upstream supply oil passage connected to a discharge port in an oil pump, a downstream supply oil passage connected to portions to be lubricated around the crankshaft, a flow-in bore which permits the upstream supply oil passage to communicate with a fluid inlet in the fluid transmitting means, and a flow-out bore which permits a fluid outlet in the fluid transmitting means to communicate with the downstream supply oil passage.
The fluid transmitting means corresponds to a torque converter T in embodiments of the present invention which will be described hereinafter.
With the first feature, during idling of the engine, the transmitting of power to the shifting clutch and the like can be cut off by controlling the shifting clutch to its OFF state irrespective of the presence of the fluid transmitting means, even in a first-speed position of the transmission, thereby preventing the creep phenomenon. During shifting, the transmission can be brought into an unloaded state, by first controlling the shifting clutch to its OFF state irrespective of the presence of the fluid transmitting means, thereby conducting the shifting lightly without generation of a torque shock.
Moreover, the crankshaft is rotated at higher speed than that of the input shaft of the transmission driven through the reducing device. Therefore, the transmitted torque borne by the fluid transmitting means and the shifting clutch mounted on the crankshaft is relatively small, and the capacities of the fluid transmitting means and the shifting clutch can be reduced correspondingly, leading to the compactness of the fluid transmitting means and the shifting clutch. Therefore, the compactness of the power unit can be achieved, despite the disposition of both the fluid transmitting means and the shifting clutch.
Further, the oil discharged by the oil pump driven by the engine flows first into the upstream supply oil passage and then, via the flow-in bore into the fluid transmitting means to contribute to the operation and cooling of the fluid transmitting means. Further, oil is discharged through the flow-out bore into the downstream supply oil passage and then supplied to the portions to be lubricated around the crankshaft to contribute to their lubrication. In this way, the lubricating oil for the engine can be utilized to operate the fluid transmitting means and hence, it is unnecessary to mount an exclusive oil pump for supplying any operating oil to the fluid transmitting means.
According to a second aspect and feature of the present invention, in addition to the first feature, the crankshaft has an orifice provided therein to permit the direct communication between the upstream and downstream supply oil passages.
With the second feature, a portion of the oil supplied from the oil pump to the upstream supply oil passage is passed through the orifice directly to the downstream supply oil passage without via the fluid transmitting means and supplied to the portions to be lubricated around the crankshaft. Therefore, the proportion of distribution of the oil to the fluid transmitting means and the engine can be determined freely by selection of the orifice.
According to a third aspect and feature of the present invention, in addition to the first feature, the transmitting system further includes a partition wall provided between the flow-in bore and the flow-out bore for partitioning the upstream and downstream supply oil passages from each other.
With the third feature, the oil supplied from the oil pump to the upstream supply oil passage is obliged to be passed through the inside of the fluid transmitting means through the flow-in bore and the flow-out bore. Thus, even if the oil pump is of a relatively small capacity or displacement, it is possible to prevent the shortage of the operating oil for the fluid transmitting means, which is effective for the small-sized vehicle.
According to a fourth aspect and feature of the present invention, in addition to any one of the first, second and third features, the fluid transmitting means comprises a torque converter which is comprised of a pump impeller connected to an input side, a turbine impeller connected to an output side,
Kihara Teruo
Makita Seiji
Yoshimoto Tokuji
Arent Fox Kintner & Plotkin & Kahn, PLLC
Bonck Rodney H.
Yutaka Giken Co. Ltd.
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