EP0228897A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Transmission ratio control system for a continuously variable transmission
Assignee: Subaru Corp
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Filing: 1986-12-23
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Granted: —
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Expires: 2006-12-23
Abstract
Abstract A control system has a transmission ratio control valve having a spool for controlling oil supplied to a cylinder of a drive pulley to change the transmission ratio. By controlling the pressure of oil supplied to one end of the spool of the transmission ratio control valve in accordance with conditions of the engine and transmission, the spool is shifted, so that the transmission ratio changing speed is controlled. Actual transmission ratio changing speed is compared with a desired changing speed to produce an error signal. In response to the error signal, the actual changing speed is converged to the desired changing speed.
Inventors
- 👤 Yoshihiko Morimoto
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 08:40
CPC Classifications
B; B60; B60W; B60W30/00; B60W30/18; B60W10/00; B60W10/04; B60W10/10; B60W10/101; B60W30/1819; F; F16; F16H; F16H61/00; F16H61/66; F16H61/662; F16H61/66254; F16H61/66259
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
205 words
A control system for a continuously variable transmission for a motor vehicle, the transmission comprising a drive pulley including a hydraulically shiftable disc and a first hydraulic cylinder for shifting the disc, a driven pulley including a hydraulically shiftable disc and a second hydraulic cylinder for operating the disc, a belt engaged with both pulleys, a spool valve for transmission ratio control and a first hydraulic circuit having a pump for supplying oil to the first and second cylinders through the transmission ratio control valve, the control system comprising; first means for detecting operating conditions of the engine and the transmission and for producing a condition signal; second means responsive to the condition signal for producing a signal representing a desired speed for changing the transmission ratio; third means responsive to the desired transmission ratio changing speed signal for shifting the spool of the transmission ratio control valve at a speed dependent on the desired speed signal; means for detecting the actual transmission ratio changing speed and for producing an actual speed signal; fourth means responsive to the desired speed signal and the actual speed signal for producing an error signal; and fifth means responsive to the error signal for correcting the desired changing speed.
Claim 2
Dependent Claim
205 words
A control system for a continuously variable transmission for a motor vehicle, the transmission comprising a drive pulley including a hydraulically shiftable disc and a first hydraulic cylinder for shifting the disc, a driven pulley including a hydraulically shiftable disc and a second hydraulic cylinder for operating the disc, a belt engaged with both pulleys, a spool valve for transmission ratio control and a first hydraulic circuit having a pump for supplying oil to the first and second cylinders through the transmission ratio control valve, the control system comprising; first means for detecting operating conditions of the engine and the transmission and for producing a condition signal; second means responsive to the condition signal for producing a signal representing a desired speed for changing the transmission ratio; third means responsive to the desired transmission ratio changing speed signal for shifting the spool of the transmission ratio control valve at a speed dependent on the desired speed signal; means for detecting the actual transmission ratio changing speed and for producing an actual speed signal; fourth means responsive to the desired speed signal and the actual speed signal for producing an error signal; and fifth means responsive to the error signal for correcting the desired changing speed.
Claim 3
Dependent Claim
36 words
A control system according to claim 1 wherein the first means comprises means for producing a desired transmision ratio signal, means for producing an actual transmission ratio signal, and means for producing an engine acceleration signal.
Claim 4
Dependent Claim
53 words
A system according to claim 1 wherein the third means includes a second hydraulic circuit for supplying oil to the transmission ratio control valve so as to shift the spool, and control valve means provided in the second hydraulic circuit for controlling the amount of oil supplied to the transmission ratio control valve.
References Cited (Backward Citations)
No citation records indexed.
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