Improvement Design And Test Of The Traction Single-Track Transporter

The production scale and output of citrus in our country have been increasing year by year.Many citrus orchards are located in hilly and mountainous areas in the southern regions,which has led to challenges in agricultural transportation of materials and fruit.To address the issue,researchers have been continuously supplementing and perfecting the transportation system in citrus orchards.The traction single-track transporters are widely used in orchards due to convenient operation and excellent climbing performance.However,the practical applications showed that the transporters still face challenges in terms of safety,stability,and installation efficiency.To tackle the issues,the traction single-track transporters were optimized and performance tests were conducted on the optimized prototype.The major research contents of this thesis are as follows:(1)In response to the problem of difficult installation of the transportation track,the track was simplified and improved,and the supporting components were optimized to achieve detachable and easy installation of the track.The mechanical analysis of the simplified track’s simply supported beam model was carried out,and the maximum shear stress borne by the track was determined to be 9.175 MPa,and the maximum bending stress was 259 MPa,verifying that the simplified track could meet the requirements for use.The supporting components were static analyzed,and the results showed that the loaded components were designed reasonably,and the detachable supporting components could meet the operational requirements.(2)To address the issue of wire rope tensioning,the elastic tensioning method for steel wire rope was proposed.The spring-type self-adaptive tensioning device was designed to be installed at the end of the rail,with a tensioning stroke of 1.3 meters.The minimum output tensioning force of the device was 287.65 N and the elasticity coefficient of the compression spring was 617.65 g/mm according to the minimum sag condition of the wire rope and the "W" shaped winding method respectively.And finally,the selection and design of the spring guide components,spiral fixing components,guide rail sliders,and supports were carried out.The static analysis of the load-bearing support plate was conducted,and the maximum stress is 191.47 MPa,which satisfies the design requirements.(3)In response to safety issues caused by steel wire rope breakage,the wedge type slow braking scheme has been proposed,using the overrunning clutch as the core component of the triggering mechanism.The mechanical characteristics of the centrifugal process of the clutch were analyzed,and the brake triggering speed was determined to be1.51 m/s.The motion analysis of the device response stage was performed to determine the braking response time of 0.36 s.In addition,the structural design and mechanical analysis were conducted on the brake mechanism components such as the lock catch and wedge block,and the lock catch push out force was determined to be 31.33 N,thereby determining the driving spring parameters.Based on the self-locking requirement,the wedge tilt angle was determined to be 25°.The dynamics of the emergency safety braking device were analyzed by using Adams simulation.The results showed that for a 40° slope,the average acceleration of the trailer after slow-down under self-weight was 2.9 m/s2,which was 31% lower than the acceleration of 4.2 m/s2 without the braking device.When the trailer slided on a 12° slope,the average deceleration was 5 m/s2,indicating a significant braking effect.When the trailer was loaded with 150 kg,the entire braking process took approximately 3.5 s,and the sliding distance was 17.5 m,which met the requirements.(4)Relevant performance tests were conducted on the optimized and improved prototype.For the spring-based adaptive tensioning device,the orthogonal test was designed considering factors such as slope,load,and operating conditions.The results showed that the maximum change in sag of wire rope was 0.65%.When the transport started at full load,the spring had the maximum extension and contraction amplitude.The thrust of the spring changed within 40 N,the device met the tension requirements.The success rate of the emergency braking device was verified through repeated tests.The results showed that when the trailer slided from the highest point,the average response time of the braking device was 1.12 s.The braking distance was 12.1 m when the trailer was empty,and the braking distance was 16.8 m when the trailer was loaded with 200 kg.The trailer could achieve slow braking to ensure safe operation.