Speed variator employing friction having an improved friction elements-tightening device
AssigneeAutomobiles Peugeot
InventorRene Leveque
Life of this patent
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Abstract
This invention has for purpose to improve the conditions of the tightening of the friction elements in a speed variator intended in particular to be employed in an automobile vehicle. It resides mainly in the use of a piston and cylinder assembly as means for pre-tightening the friction elements, this assembly defining a pressure chamber which is connected to the lubrication oil supply pump and to a relatively small-section discharge path. This arrangement permits modulating the pressure of the pre-tightening over a wide range in principle as a function of the temperature of the oil. Preferably, there is also provided a further correction as a function of the speed ratio established in the variator.
Claims9
In a speed variator comprising a housing, a first shaft, a second shaft parallel to the first shaft, friction elements, a first series of said friction elements connected to rotate with the first shaft, a second series of said friction elements connected to rotate with the second shaft, the first series of elements being tightenable between the second series of elements, means for varying the eccentricity between the axes of rotation of the two shafts, and a device for tightening the friction elements against each other comprising a support member fixed to the housing at a first end of the friction elements, a tightening member mounted to be movable in the housing in a direction parallel to the shafts and located adjacent a second end of the friction elements opposed to said first end and movable to exert a pressure on said second end of the friction elements to urge the friction elements against the support member, pre-tightening means cooperable with the tightening member to exert a pre-tightening force on the tightening member substantially just enough to tighten the friction elements together and render them sufficiently effective when starting to transmit torque through the variator, and main tightening means cooperable with the tightening member for exerting a force on the tightening member which is proportional to the torque transmitted;
- the improvement comprising for constituting the pre-tightening means at least one piston and cylinder arrangement defining a chamber and interposed between the housing and the tightening member, a source of lubricating oil for the variator, lubricating oil path means putting said source in communication with surfaces of the variator which need to be lubricated, means connecting said lubricating oil path means to the chamber, a lubricating oil discharge path means connected to the chamber, the discharge path means having a sufficiently small cross section with respect to the rate of flow of the lubricating oil from the source to ensure that the lubricating oil contained in the chamber is maintained under pressure for exerting a pre-tightening force on the tightening member prior to the exertion of the tightening force by the main tightening means.
Dependencies are inferred from the claim text.