Method for controlling a continuously variable transmission and transmission equipped with a control system for implementing said method

By employing a drillless rolling control method and energy recovery technology for hydraulic motor-pump components, the problem of excessive hydraulic pressure increase during rapid ratio changes in continuously variable transmissions (CVTs) has been solved, improving system efficiency and robustness while reducing energy consumption.

CN115485489BActive Publication Date: 2026-05-26MAZZARO PLC
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
MAZZARO PLC
Filing Date
2020-03-30
Publication Date
2026-05-26

AI Technical Summary

Technical Problem

Existing continuously variable transmissions (CVTs) require excessive increases in hydraulic pressure during rapid ratio changes, leading to inefficiency and susceptibility of solenoid valves to fouling.

Method used

By employing a drillless rolling control method in the continuously variable transmission (CVT), the clamping of the ring gear and sun gear is controlled using static normal forces NR and NZ, avoiding the addition of dynamic components during ratio changes. The energy consumption of the hydraulic system is reduced by utilizing hydraulic motor-pump assemblies and energy recovery technology.

Benefits of technology

This achieves efficient control during rapid ratio changes, reduces energy consumption in the hydraulic system and pressure drop issues in the solenoid valves, and improves the robustness and efficiency of the system.

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Abstract

The method of the present invention is a method for controlling a non-drilling profiled CVT, which includes a ring gear (1), a set of planetary gears (3), and a sun gear (2), wherein the ring gear and the sun gear are clamped together. As in prior art profiled CVTs, when the gear ratio is constant, i.e., when the pivot angle (8) of the planetary gears is constant, the normal forces (NR, NZ) between the ring gear and sun gear on one side and the planetary gear on the other side are well defined. The normal force for a constant ratio is referred to as the static value of the normal force. The method is configured such that during a continuous increase or decrease in the gear ratio, any component of the static value of the first and / or second normal forces is zero or less than the predefined component required to maintain the micro-slip condition of rolling contact between the planetary gears (3) and the ring gears and sun gears (1, 2). This control of the force is possible regardless of the rate of change of the ratio. The transmission according to the invention is equipped with a control system suitable for implementing this method.
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