Friction gear transmission systems or components – With lubrication
Reexamination Certificate
1999-08-02
2001-03-20
Herrmann, Allan D. (Department: 3682)
Friction gear transmission systems or components
With lubrication
C476S042000
Reexamination Certificate
active
06203467
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to lubrication of a toroidal continuously variable transmission used in a vehicle.
BACKGROUND OF THE INVENTION
In a vehicle wherein the drive force of the engine is transmitted to drive wheels via a torque converter, a forward/reverse change-over mechanism and a toroidal continuously variable transmission, the forward/reverse change-over mechanism is lubricated with lubricating oil which is generally supplied from an oil pump while the continuously variable transmission is lubricated with oil supplied by the torque converter via an oil cooler. In the continuously variable transmission, the lubricating oil is supplied to contact surfaces between an input disk, an output disk and power rollers gripped between these disks, and to thrust bearings of the power rollers.
SUMMARY OF THE INVENTION
However, as the torque converter generally has a low pressure resistance, the pressure of lubricating oil sent to the oil cooler from the torque converter is low. Hence, at low temperature at which the resistance to passage of oil increases, the amount of lubricating oil supplied to the continuously variable transmission tends to be inadequate.
On the other hand, when the input disk and output disk are at high temperature, a large temperature difference arises between the lubricating oil adhering to the disks and the lubricating oil supplied from the oil cooler. As a result, a large difference occurs in the surface tensions of these lubricating oils, low temperature lubricating oil at the lubricating oil boundary forms droplets, and these droplets are eliminated by the surface tension of the high temperature lubricating oil which tends to lower the lubricating efficiency.
It is therefore an object of this invention to supply a sufficient amount of lubricating oil to a continuously variable transmission.
It is a further object of this invention to improve lubrication of the contact parts of the disks and power rollers.
In order to achieve the above objects, this invention provides a lubricating mechanism of a toroidal continuously variable transmission for a vehicle. The transmission comprises an input disk and output disk accommodated in a case, a power roller gripped between the input disk and output disk, and a bearing supporting the power roller. The lubricating mechanism comprises a torque converter for transmitting a rotation of an engine to the transmission, this torque converter having a function to provide a lubricating oil, an oil pump driven by the engine for pressurizing a lubricating oil, a first supply port for supplying lubricating oil to a contact surface of the power roller with the input disk and output disk, a second supply port for supplying lubricating oil to the bearing, a first oil passage for connecting the oil pump to either one of the first supply port and second supply port, and a second oil passage for connecting the torque converter to the other one of the first supply port and second supply port.
The details as well as other features and advantages of this invention are set forth in the remainder of the specification and are shown in the accompanying drawings.
REFERENCES:
patent: 3598740 (1971-08-01), Duling et al.
patent: 6045480 (2000-04-01), Sakai et al.
patent: 6056094 (2000-05-01), Sakai
Nakano Masaki
Yamamoto Hideharu
Foley & Lardner
Herrmann Allan D.
Nissan Motor Co,. Ltd.
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