Failure determination device for stepless speed changer and failure determination device for start clutch

Abstract

There is provided a failure determination system for a continuously variable transmission of a belt type, which is capable of determining failure of control valves for performing speed varying operation, and enhancing maintainability. An ECU controls a transmission ratio of the transmission to a fixation-determining LOW-side range when the vehicle is standing. When the transmission ratio during stoppage of the vehicle is within a stop-time OD-side range if engine torque > / = OD-time DR-side reference torque and at the same time the transmission ratio < DN-side reference value hold, the ECU determines that the DR solenoid valve is faulty, and if the throttle valve opening > / = OD-side reference value, the transmission ratio > / = DN-side reference value, and at the same time a vehicle speed < OD-side reference value hold, the ECU determines that the DN solenoid valve is faulty.

Description

technical field [0001] The present invention relates to a failure judging device for a belt type continuously variable transmission that performs a shifting operation by winding a belt between two pulleys of a variable pulley width type and changing the pulley width of the two pulleys with oil pressure supply from a control valve, and The device for determining the failure of the start clutch, which is installed between the transmission of the vehicle and the drive wheels, and controls the coupling force by the oil pressure supply of the control valve, particularly relates to the determination of the failure of these control valves. Background technique [0002] In the past, as a fault determination device for a continuously variable transmission, for example, Japanese Patent Application Laid-Open No. 60-157553 (pages 2-12, Figure 13 ) device recorded. This continuously variable transmission is mounted on a vehicle and includes: a drive side pulley of a variable pulley widt...

AI Technical Summary

Problems solved by technology

However, since this failure determination device only performs failure determination of the solenoid of the solenoid valve, the failure determination device of the conventional continuously variable transmission cannot distinguish the hydraulic circuit components of the solenoid valve for the same reason as described above. failure and failure of the hydraulic circuit other than the solenoid valve

As a result, even if only the hydraulic circuit part of the solenoid valve fails, the fault cannot be identified, and it can only be judged as a failure of the entire hydraulic circuit. Therefore, in order to identify the fault location, the entire hydraulic circuit must be checked. Check the operation, there is a problem of poor maintainability

In particular, when the fault location cannot be identified, it is necessary to replace the entire hydraulic circuit

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