【摘要】：搖臂作為大型液壓裝載機的關(guān)鍵受力構(gòu)件,對裝載機的工作壽命與安全可靠性起著至關(guān)重要的作用。目前,鑄造成形搖臂重量較大,機械性能不高,嚴(yán)重影響裝載機的安全可靠性,已無法滿足大噸位裝載機的使用要求。鍛造成形工藝可在保證制件尺寸特征的同時,大幅度提高強度,采用鍛造工藝取代鑄造工藝成形搖臂鍛件是保證大型液壓裝載機安全可靠性的有效方法和必然趨勢。然而,搖臂體積約為5.8×107 mm3,重量達400 kg,鍛造成形工藝復(fù)雜,不能簡單直接運用現(xiàn)有的鍛造工藝進行生產(chǎn),通過有限元模擬手段開展搖臂鍛件結(jié)構(gòu)參數(shù)優(yōu)化設(shè)計和成形工藝模擬研究,對后續(xù)實際生產(chǎn)具有重要指導(dǎo)意義。本文以大型液壓裝載機搖臂鍛造成形工藝為研究對象,基于鑄件與鍛件設(shè)計原則的不同對搖臂結(jié)構(gòu)進行了相應(yīng)改進。在不改變搖臂結(jié)構(gòu)安裝尺寸、滿足使用剛度和強度前提下,以減小搖臂的重量為優(yōu)化目標(biāo)對搖臂進行靜力分析,采用遺傳算法進行了結(jié)構(gòu)參數(shù)優(yōu)化。采用Gleeble-1500D熱模擬試驗機對搖臂用35Mn B鋼進行了高溫等溫單向熱壓縮實驗,研究其在790~1190℃、0.01~10 s-1下的變形行為,并構(gòu)建了其本構(gòu)方程。在搖臂鍛件結(jié)構(gòu)參數(shù)優(yōu)化的基礎(chǔ)上,對搖臂鍛造成形工藝進行了分析,并基于剛塑性有限元法對搖臂鍛造成形過程進行了數(shù)值模擬。優(yōu)化后的搖臂在最大載荷工況下,最大應(yīng)力與最大偏移量分別為211.24MPa、0.95 mm,均小于搖臂的許用應(yīng)力和許用偏移量,搖臂重量減少了20.12%,實現(xiàn)了優(yōu)化目的。通過搖臂成形模擬分析,獲得了搖臂鍛造模擬成形過程中金屬坯料的應(yīng)力、應(yīng)變、溫度場以及鍛錘行程載荷曲線等數(shù)據(jù)。根據(jù)搖臂成形模擬分析結(jié)果,并結(jié)合結(jié)構(gòu)特征及成形工藝設(shè)計了搖臂鍛造成形模具和切邊模具。采用鍛錘對搖臂進行了鍛造生產(chǎn)試制,搖臂鍛造試制件成形飽滿,無明顯缺陷,驗證了搖臂鍛造成形工藝的可行性。通過本文研究,為大型液壓裝載機搖臂鑄改鍛結(jié)構(gòu)優(yōu)化和實際鍛造成形工藝的完善提供理論依據(jù)。
[Abstract]:Rocker arm, as the key component of large hydraulic loader, plays an important role in the working life and safety of loader. At present, the heavy weight and low mechanical properties of the casting rocker arm seriously affect the safety and reliability of the loader, and can not meet the requirements of the large tonnage loader. The forging process can guarantee the dimension characteristics of the parts and increase the strength greatly. It is an effective method and inevitable trend to replace the casting process to form the rocker arm forgings by forging technology to ensure the safety and reliability of large hydraulic loaders. However, the rocker arm's volume is about 5.8 脳 10 ~ 7 mm3, the weight is up to 400 kg, the forging process is complicated, and the existing forging technology can not be used to produce the rocker arm directly. The optimization design of structural parameters of rocker forging and the simulation of forming process by means of finite element simulation are of great significance for subsequent practical production. In this paper, the rocker arm forging technology of large hydraulic loader is studied, and the rocker arm structure is improved based on the difference of design principle between castings and forgings. On the premise of not changing the installation size of rocker arm and satisfying the stiffness and strength of the rocker arm, the static analysis of rocker arm is carried out with the objective of reducing the weight of rocker arm, and the structural parameters are optimized by genetic algorithm. The high temperature isothermal unidirectional thermal compression test of rocker arm 35Mn B steel was carried out by Gleeble-1500D thermal simulator. The deformation behavior of the steel was studied at 790 鈩，

本文編號：2375155