【摘要】：一般常用的機械系統(tǒng)、設備或裝置都是長期運行、反復使用的，本文稱之為“常規(guī)機械”。而在某些特殊場合中，有一類機械只使用一次后就被放棄不用，這類機械被稱為“一次性機械”。一次性機械中的機械零件可以籠統(tǒng)地稱為“一次性機械零件”。一次性機械零件的設計理論和方法與常規(guī)機械零件設計方法應當有所不同，然而，由于目前并未對一次性機械零件與常規(guī)機械零件給予明確的區(qū)分，所以一次性機械零件的設計仍然沿用常規(guī)機械零件的設計思想和方法，這就導致將常規(guī)機械設計準則中用于一次性機械零件設計時，不可避免的出現設計結果冗余，造成整體設計指標下降，有時甚至無法滿足設計要求。雖然采用試驗樣機法在一定程度上能夠完成一次性機械的研制，但是該方法的研制周期較長、效率較低、成本過高，不能滿足日益增加的研制任務要求。因此，有必要深入研究一次性機械零件的設計理論和方法，以便為一次性機械設計理論體系的建立打下基礎。 在歸納總結常規(guī)機械零件設計準則和方法的基礎上，本文將一次性機械中承受循環(huán)載荷次數少的機械零件定義為一次性機械零件，明確了一次性機械零件不同于常規(guī)機械零件的基本特征，提出了在一次性機械零件設計時應該遵循的基本原則，并通過與常規(guī)機械零件設計方法的對比計算，闡明了一次性機械零件概念提出的意義。 在提出了一次性機械零件概念的基礎上，本文研究了一次性機械零件與常規(guī)機械零件的區(qū)分界限。首先，基于疲勞理論，根據機械零件失效形式的不同，將一次性機械零件劃分為兩類分別進行研究。特別針對發(fā)生彈性失效的情況，以常用齒輪鋼40Cr為試驗材料，深入研究了40Cr在較高循環(huán)應力水平下的低周疲勞失效和棘輪失效行為。根據實驗結果，定義了產生0.2%的總塑性應變時所對應的循環(huán)載荷作用次數為疲勞彈性失效壽命，并用疲勞彈性失效替代疲勞斷裂作為高應力作用下的一次性機械零件疲勞失效的判斷依據，修正了材料在高應力作用下的疲勞失效壽命模型。為了滿足一次性機械零件的高可靠性要求，在40Cr的疲勞特性研究中，根據試驗結果，確定了疲勞彈性失效壽命的概率分布類型為三參數Weibull分布，并采用灰色估計和最大相關系數優(yōu)化法進行了參數估計，在參數估計中依據最可靠原則來確定疲勞概型參數，在提高材料許用應力范圍的同時保證一次性機械零件高可靠性要求。 本文還以直齒漸開線圓柱齒輪零件為例研究了典型一次性機械零件的設計方法。在研究過程中，規(guī)劃了一次性齒輪零件的研究內容，繼承和改進了常規(guī)齒輪零件設計準則和方法，，使之適用于一次性齒輪零件的設計。建立了小模數直齒漸開線圓柱齒輪的低周疲勞強度設計模型。該模型由兩個子模型組成，首先建立了基于嚙合過程的齒輪接觸有限元仿真模型，利用該模型研究了較高載荷下齒輪的齒間載荷分布特征，分析了主要安裝誤差對齒輪應力狀態(tài)的影響，獲取齒根處應力應變信息。然后，基于FS模型和臨界平面理論，利用有限元模型得到的應力應變信息，進行了齒根彎曲強度設計。為驗證該疲勞強度設計模型的準確性，研制了小模數齒輪對稱疲勞試驗機。以40Cr小模數齒輪為試驗對象，驗證了所建立的疲勞強度設計模型的有效性。 開展了某型號箭用舵機減速器的研制工作，該減速器采用諧波傳動形式，減速比300，具有輸出80Nm扭矩的能力，總重量約1000g。在研制過程中，采用一次性機械零件設計方法，運用所建立的疲勞強度設計模型，對直筒形柔輪的進行了疲勞強度設計，最后，通過專用測試臺測試了所研制的諧波減速器性能，結果表明各項指標均滿足要求。
[Abstract]:The commonly used mechanical systems, equipment, or devices are long-term, repeated use, referred to herein as" General Machinery ". In some special situations, there is a class of machines that have been abandoned only once, and this type of machine is called" One-time machine ". mechanical parts in a disposable machine may be generally referred to as" One-time mechanical part". The design theory and method of the one-time mechanical part should be different from the conventional mechanical parts design method, however, since there is no explicit distinction between the one-time mechanical part and the conventional mechanical part, Therefore, the design of the one-time mechanical part still follows the design idea and method of the conventional mechanical parts, which leads to the inevitable design result redundancy when the conventional mechanical design criterion is used for the design of a disposable mechanical part, so that the overall design index is reduced, Sometimes you can't even meet the design requirements. Although the test prototype method can accomplish the development of one-time machinery to a certain extent, the development period of the method is long, the efficiency is lower, the cost is too high, and the requirements for the development task are not met. Therefore, it is necessary to study the design theory and method of one-time mechanical parts in order to lay the foundation for the establishment of one-time mechanical design theory system. On the basis of summarizing the design criteria and methods of conventional mechanical parts, this paper defines the mechanical parts with few times of cyclic loading in one-time machinery as one-time mechanical parts, and makes it clear that one-time mechanical parts are different from the basic mechanical parts. In this paper, the basic principle which should be followed in the design of one-time mechanical parts is put forward, and the concept of one-time mechanical parts is clarified by the comparison calculation with the conventional mechanical parts design method. On the basis of putting forward the concept of one-time mechanical parts, this paper studies one-time mechanical parts and conventional mechanical parts. First, based on the fatigue theory, the one-time mechanical part is divided into two categories according to the different failure modes of mechanical parts. Don't conduct the research. Especially for the case of elastic failure, the low-cycle fatigue failure and the ratchet of 40Cr at higher cyclic stress level were studied by using 40Cr as the test material. According to the experimental results, the number of cyclic loads corresponding to the total plastic strain of 0.2% is defined as the fatigue elastic failure life, and the fatigue failure is replaced by fatigue elastic failure as a one-time mechanical part fatigue failure under the action of high stress. According to the judgment basis, the fatigue loss of the material under the action of high stress is corrected. In order to meet the high reliability requirement of one-time mechanical parts, the probability distribution type of fatigue elastic failure life is determined as three-parameter Weibull distribution according to the experimental results, and the grey estimation and the maximum correlation coefficient optimization method are adopted in the study of the fatigue properties of 40Cr. Parameter estimation, based on the most reliable principle in the parameter estimation, to determine the fatigue almost-type parameter, in order to increase the allowable stress range of the material, guarantee the high-time mechanical part height Reliability requirements are also studied in this paper. The typical disposable machine is also studied in this paper. In the research process, the research contents of one-time gear parts are planned, and the design criteria and methods of conventional gear parts are inherited and improved so as to be applicable to one time. Design of gear parts with small modulus and low circumference of involute cylindrical gear with small modulus The fatigue strength design model is composed of two sub-models. First, a finite element simulation model of gear contact based on meshing process is established. The distribution characteristics of interdental load of gears under high load are studied by using this model. The main installation error is analyzed. The influence of the stress state of the wheel and the acquisition of teeth Then, based on FS model and critical plane theory, the stress strain information obtained by finite element model is used. In order to verify the accuracy of the fatigue strength design model, small modulus teeth have been developed. The fatigue strength of the wheel is verified by using 40Cr small modulus gear as the test object. The design model is effective. The development of a steering gear reducer for an arrow is carried out. The reducer is in the form of harmonic drive, with a reduction ratio of 300, and has the capability of outputting 80Nm. The strength and total weight are about 1000g. During the development process, the design method of the one-time mechanical parts is adopted, the fatigue strength design of the straight cylindrical flexible wheel is designed by using the established fatigue strength design model, and finally, the test bench is tested through the special test bench. The performance and results of the developed harmonic reduce
【學位授予單位】：哈爾濱工業(yè)大學
【學位級別】：博士
【學位授予年份】：2013
【分類號】：TH112;TH13

【參考文獻】

相關期刊論文 前1條

1 鄧聰;;基于靈敏度分析方法的諧波減速器柔輪的疲勞強度研究[J];機械傳動;2012年10期

本文編號：2301994