Control system for variation of the sheave ratio in a continuously variable transmission
First Claim
1. A control system for a continuously variable transmission having a first variable pulley with a first effective diameter disposed on a first shaft, a second variable pulley disposed on a second shaft, and an endless belt means for interconnecting said first and second variable pulleys passing around said pulleys at a belt-pass frequency and transmitting torque therebetween, said control system comprising:
- means for developing a first signal for regulating said first effective diameter of said first variable pulley;
means for developing a second signal, said second signal having a frequency substantially different from said belt-pass frequency; and
means for modifying said first effective diameter with said second signal.
2 Assignments
0 Petitions
Accused Products
Abstract
A control system for a continuously variable transmission reduces the noise generated as a result of the use of an articulated belt for connecting the first and second variable pulleys. The control system dithers the ratio set point in order to prevent a cyclic repetition of the forces between the belt and the pulleys. This reduces the amplitude of noise peaks generated at discrete frequencies by operation of the transmission resulting in a decrease in the level of perceived noise.
11 Citations
12 Claims
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1. A control system for a continuously variable transmission having a first variable pulley with a first effective diameter disposed on a first shaft, a second variable pulley disposed on a second shaft, and an endless belt means for interconnecting said first and second variable pulleys passing around said pulleys at a belt-pass frequency and transmitting torque therebetween, said control system comprising:
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means for developing a first signal for regulating said first effective diameter of said first variable pulley; means for developing a second signal, said second signal having a frequency substantially different from said belt-pass frequency; and means for modifying said first effective diameter with said second signal. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A control system for a continuously variable transmission having a first variable pulley and a second variable pulley and an endless belt means rotating about said variable pulleys at a belt-pass frequency and transferring torque between said first and second variable pulleys, the control system comprising:
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means for developing a first signal representative of a set point ratio between said first and second variable pulleys; means for developing a second signal of a frequency or frequency range low relative to the belt-pass frequency; means responsive to said second signal for modulating said first signal to provide a third signal; and
,means responsive to said third signal for regulating said set point ratio between said first and second variable pulleys. - View Dependent Claims (8, 9, 10)
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11. A method of reducing the perceived level of noise generated in a continuously variable transmission having a first variable pulley, a second variable pulley, and an endless belt means for interconnecting said first and second variable pulleys, said belt means rotating around said pulleys at a belt-pass frequency and transferring torque between said first and second variable pulleys, said method comprising the steps of:
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developing a first signal for providing a predetermined torque ratio between said first and second variable pulleys; developing a second signal of a frequency or frequency range low relative to the belt-pass frequency; generating a third signal by modulating the first signal in accordance with the second signal; and
,regulating the ratio of torque between the first and second pulleys in response to the third signal. - View Dependent Claims (12)
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Specification