Estudio de fallas y propuesta de reacondicionamiento de los engranajes de la caja de cambio de los autos Lada 2105
Fecha
2021
Autores
Pérez Roble, Daniel
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Editor
Universidad Central “Marta Abreu” de Las Villas. Facultad de Ingeniería Mecánica e Industrial. Departamento de Ingeniería Mecánica
Resumen
El presente trabajo aborda un estudio de fallas de los engranajes de la caja de cambios de los autos tipo Lada 2105, a partir de lo cual se elaboran propuestas de procedimientos para el reacondicionamiento de las zonas de trabajo afectadas por roturas. Como resultado del estudio se constató que estos elementos de máquinas trabajan bajo severas condiciones de explotación, lo que unido a factores externos (mala manipulación por parte del conductor) conllevan al fallo de la pieza. La pérdida de los requisitos de la zona de trabajo de estas piezas se debe fundamentalmente al desgaste, evidenciado en tres mecanismos fundamentales, el adhesivo, la fatiga superficial y el abrasivo, a lo que se suma la rotura de los dientes por sobrecargas, generalmente combinada con deterioros previos. Los fallos se asocian principalmente a lubricación inadecuada y a malas prácticas en la manipulación del sistema de transmisión. Para la recuperación de los dientes con fractura total se elaboraron procedimientos con el empleo del proceso SMAW, utilizando un consumible con clasificación AWS E312-16 y un régimen de soldadura con 65 A de corriente, 20 V de voltaje y 4,5 m/h de avance de la soldadura. Para los dientes con fracturas en sus extremos se propone el uso del proceso GTAW, empleando un consumible de diámetro 1,6 mm con clasificación AWS ER312 y un electrodo no consumible de diámetro 2,4 mm y clasificación AWS EWTh-1, un régimen de soldadura con 100 A de corriente y un flujo de gas argón de 0,6 a 1 m3/h. En cualquiera de las dos variantes se requiere realizar precalentamiento a 150 ºC con enfriamiento lento luego de la soldadura, así como la aplicación de técnicas para minimizar las tensiones residuales.
The present work deals with a study of failure of the gearbox gears of the Lada 2105 type cars, from which procedural proposals are elaborated for the reconditioning of the work zones affected by breakages. As a result of the study, it was found that these machine elements work under severe operating conditions, which together with external factors (bad handling by the driver) lead to part failure. The loss of the requirements of the work area of these pieces is mainly due to wear, evidenced in three fundamental mechanisms, the adhesive, the superficial fatigue and the abrasive, to which, the breakage of the teeth due to overloads, generally combined with previous deterioration, is added. The failures are mainly associated with inadequate lubrication and poor practices in handling the transmission system. For the recovery of teeth with total fracture, procedures where the use of the SMAW process is proposed were developed, using a consumable with AWS E312-16 classification and a welding regime with 65 A current, 20 V voltage and 4,5 m / h of welding advance. For teeth with fractures at their ends, the use of the GTAW process is proposed, using a ,6 mm diameter consumable with AWS ER312 classification and a non-consumable electrode with 2,4 mm diameter and AWS EWTh-1 classification, a regime of welding with 100 A current and an argon gas flow of 0,6 to 1 m3/h. Either of the two variants requires preheating to 150 ºC with slow cooling after welding, as well as the application of techniques to minimize residual stresses.
The present work deals with a study of failure of the gearbox gears of the Lada 2105 type cars, from which procedural proposals are elaborated for the reconditioning of the work zones affected by breakages. As a result of the study, it was found that these machine elements work under severe operating conditions, which together with external factors (bad handling by the driver) lead to part failure. The loss of the requirements of the work area of these pieces is mainly due to wear, evidenced in three fundamental mechanisms, the adhesive, the superficial fatigue and the abrasive, to which, the breakage of the teeth due to overloads, generally combined with previous deterioration, is added. The failures are mainly associated with inadequate lubrication and poor practices in handling the transmission system. For the recovery of teeth with total fracture, procedures where the use of the SMAW process is proposed were developed, using a consumable with AWS E312-16 classification and a welding regime with 65 A current, 20 V voltage and 4,5 m / h of welding advance. For teeth with fractures at their ends, the use of the GTAW process is proposed, using a ,6 mm diameter consumable with AWS ER312 classification and a non-consumable electrode with 2,4 mm diameter and AWS EWTh-1 classification, a regime of welding with 100 A current and an argon gas flow of 0,6 to 1 m3/h. Either of the two variants requires preheating to 150 ºC with slow cooling after welding, as well as the application of techniques to minimize residual stresses.
Descripción
Palabras clave
Mecánica Automotriz, Auto Lada 2105, Caja de Velocidad, Engranaje