AUTOMATIC AND MANUAL TRANSMISSION

Different between Manual and Automatic Transmission (gearbox)

Different between Manual and Automatic Transmission (gearbox)

Introduction

Gearboxes are among the most relevant mechanisms in industrial machinery, automotive applications, and in our daily lives. They are widely used to transmit power and produce high rotational speeds or change the direction of motion. Because of their growing use in modern technology, gearbox health monitoring and early fault detection has become the subject of intensive investigation and research. Condition monitoring of gearboxes plays a vital role in ensuring the reliability and low-cost operation of industrial facilities.

The main task of the designer is to select an appropriate gear material and manufacturing technology, combining all the possible factors to insure the high reliability of the gearbox. Even with adequate design, however, the gearbox may still break down eventually. For example, the most common of all failures that cause motor-craft accidents are failures in the drive train or one of the gearboxes. Since lie unexpected failure of a gearbox may cause significant economic loss and even threaten human life. The safety of gearboxes becomes a significant factor in mechanical safety. Thus, it is necessary to consider complete condition monitoring so as to give early warning of wear and faults. Versicherungs found that 60% of gearbox damage is due to faults in the gears, and about 90% of gear faults are due to localized gear damage.

Background

Gears effectively work in harsh conditions. They undergo deterioration of their state, especially on their teeth. There are three categories of gear defects: manufacturing defects (tooth profile error, eccentricity of wheels, etc.), installation defects (parallelism, etc.) and defects appearing during transmission (tooth wear, crack, spalling, etc.). These defects cause transmission error and may lead to gearbox failure. Since the operation of gears always results in repeated loading, this is the main factor that causes the appearance of a fatigue crack in the root of the tooth, thereby reducing structural integrity. Most of the time, a fatigue crack, starts from a flaw and may not be considered a serious problem, to begin. As the tooth crack propagates, however, cumulative damage will occur and result ultimately in primary tooth breakage.

Tooth breakage is the most serious failure for a gearbox, one which may lead to the complete failure of the gear. If the fault can be detected early and tracked as it develops, the gear can be replaced before catastrophic failure occurs. Because of its practical importance, crack identification in structures has been the subject of intensive investigation in the last three decades. Many studies have been carried out on machine monitoring in recent years, and the vibration-based technique is manifestly the most commonly used method. The appearance and growth of a gear tooth crack will leave signatures in vibration signals collected from the gearbox. The purpose of this work is to detect and measure such kinds of signatures for effective fault diagnosis and condition-based maintenance decision making.

Discussion

A historically, automatic gearboxes sapped power, hammer fuel consumption and came with only three ...