外文翻譯--萬(wàn)向節(jié)十字軸總成失效分析

附 錄 Cross-axis gimbal assembly Failure Analysis The main function of joints in different axis passing between the rotating shaft torque, it has been widely used in various types of truck axle shaft connected between the cross section, usually in the course of cross-axis universal joint of the Needle Roller Bearings for rotary movement is not, but for the rotation of the swing movement, the load cycle changes submitted. Based on the heavy-duty vehicle WX0082 Cross-axis gimbal assembly of less than life pieces of the failure mode of failure, failure, structural parameters and materials used and the performance of finite element analysis and other methods to conduct a comprehensive comparative analysis of product performance a design improvement. 1. Oblique imprint The author of a company from the provision of three packs of the three packs of Service returned failure cases observed that the cross-axis oblique journal imprint is relatively serious, bearing rings also produce the inner wall of the imprint, but the depth of cross-axis than the light. By the analysis of joints installed on the bearing assembly, when the total space bearing a larger circle, the needle easily skewed, with the result that journal have a cross-axis tilt angle with the axis of the embossing, the embossing depth of the expansion of more deep, the needle will not be able to spin, thus increasing frictional resistance, exacerbated by the extension of indentation. The total circumference of its appropriate space should be controlled in the range of 0.1 0.4mm inside, JB/T3232 in a given space for a total circumference of not more than 0.5mm. 2. Fatigue spalling Shaft angle in the use of a smaller state, universal joint assembly of the needle bearing journal diameter and cross-axis angle in the framework of repeated smaller swing, when the cross-axis with the bearing radial clearance with the wear and tear expansion will lead to concentration of load, the load will be large local indentation fatigue prematurely in order to develop into a large area off the fatigue. Especially in the cross-axis the first axis, the stress concentration due to the impact of parts of their set was almost all the chamfering eat, severe high temperature sintering under a state of the phenomenon. Because users do not use lubricants or as a result of time added on the universal joints bearings sealed properly, resulting in early loss of oil-bearing materials as well as the dust temperature intolerance, lip oil seals in the winter cold weather aging cracks under so that the early loss of grease. In addition, the universal joint assembly less oil in operation due to high temperature generated, so that shaft bearings and killed, resulting in a broken needle and the damage to seals and dust jacket, traces of ferrule surface ablation, the failure mode of both failure mode is non-normal. 4. Needle failure I lapsed from the universal joint assembly observed in the sample found that the majority of needle point of the surface there are Ma, Ma Hang, and large-scale fatigue spalling, a small number of needle head was broken, a small number of needle from the needle about 1.5mm Department head Ma Hang, and the existence of a larger phenomenon of bite wounds, the majority of needle fracture fracture from here, this occurrence of the main bearing structure and the size parameters and the circular design of the total gap. 5. Gasket failure Gasket is the first universal joint assembly of the components failure, the form of gasket failure nylon fracture and wear pads. I carefully analyzed samples gasket failure found that the outer gasket has obvious cracks, gasket has cracks and debris outside. Obviously, the gasket is the gasket by the external force resulting in rise of the local stress concentration, once the gasket external damage to the axial force will be borne by the rest of the pads to bear, the bear pads per unit area will increase the power, the entire pad tablets to be broken. Hence the need for well-designed shape and bearing structure pads. At the same time, each gasket failure due to damage and wear has been associated with failure, the gasket material must be selected high strength and wear resistance of materials. 6. Cross-axis fracture Cross shaft fracture is usually a serious overloading the user under the premise of the factors or unusual conditions occur, as joints in the design of the Department of full compliance with the standards of universal joints JB/T8925-2008 static torsional strength safety factor of 2.5 times the provisions of However, OEMs fault occ urred during the three packs of the proportion of the total failure still accounts for 2% 5% of such cases is sudden, but inevitable, universal joints and therefore the static torsional strength of match, we must maximum output torque in the engine 3 times more specific in order to avoid overloading caused the emergence of sudden failure. 7. Metallographic test analysis Cases of failure to carry out physical and chemical analysis, respectively, in the cross shaft, ferrule and needle selection of the typical characteristics of the location of the site, cutting under the specimen and along the vertical cross-section metallographic sample preparation, the microstructure-level qualified. To determine the cross shaft, ferrule and the center needle hardness, respectively, by micro-hardness of various parts of a gradient distribution of Vickers hardness measured, and its basically in line with the hardness of the hardness distribution. Check the cross-axis universal joints, a test piece of the outer ring and a number of needle samples in 50% hydrochloric acid aqueous solution heated to 70 80 , heating of about 1h, check for hot acid found in various parts use burn phenomenon exists. This burn is to determine universal joints sealed as a result of poor performance and fat loss properties of the oil well, resulting in fever bearing universal joints burn too soon after the failure of the parts. 萬(wàn)向節(jié)十字軸總成失效分析 萬(wàn)向節(jié)的主要作用是在不同軸線上的軸之間傳遞旋轉(zhuǎn)轉(zhuǎn)矩，它被廣泛應(yīng)用于各類卡車的傳動(dòng)軸聯(lián)接軸節(jié)叉之間，通常在使用過(guò)程中萬(wàn)向節(jié)十字軸上的滾針軸承不是作旋轉(zhuǎn)運(yùn)動(dòng)，而是作旋轉(zhuǎn)擺動(dòng)的運(yùn)動(dòng)，其載荷呈交變的周期變 化。本文是通過(guò)對(duì)重型載車用 WX0082 萬(wàn)向節(jié)十字軸總成壽命不足失效件的失效形式、失效原因進(jìn)行分析。 分析結(jié)果如下： 1.斜壓印 從某公司三包服務(wù)處提供的三包退回失效件中觀察到，十字軸軸頸斜壓印情況比較嚴(yán)重，軸承套圈內(nèi)壁也產(chǎn)生相應(yīng)的壓印，但深度要比十字軸輕。經(jīng)分析，安裝在萬(wàn)向節(jié)總成上的軸承，當(dāng)軸承圓周總間隙較大時(shí)，滾針易產(chǎn)生歪斜，致使十字軸軸頸產(chǎn)生與軸線傾斜一定角度的壓印，當(dāng)壓印深度擴(kuò)展較深時(shí)，滾針就不能自轉(zhuǎn)，因此使摩擦阻力增大，加劇壓痕的延伸。其合適的圓周總間隙應(yīng)控制在0.1 0.4mm 范圍內(nèi)， JB/T3232 中給定的圓周總間隙為不超過(guò) 0.5mm。 2.疲勞剝落 在傳動(dòng)軸擺角較小的使用狀態(tài)下，萬(wàn)向節(jié)總成上的滾針軸承內(nèi)徑與十字軸軸頸在較小角度范圍內(nèi)反復(fù)擺動(dòng)，當(dāng)十字軸與軸承徑向游隙隨著磨損而擴(kuò)大時(shí)，會(huì)導(dǎo)致產(chǎn)品載荷集中，載荷大的地方就會(huì)過(guò)早地產(chǎn)生疲勞壓痕，從而發(fā)展成為大面積的疲勞剝落。特別是在十字軸軸頭處，由于應(yīng)力集中影響，其受載部位的倒角幾乎全部被啃掉，嚴(yán)重時(shí)會(huì)在高溫狀態(tài)下出現(xiàn)燒結(jié)現(xiàn)象。 3.缺油燒蝕 由于在使用過(guò)程中用戶不按期加注潤(rùn)滑油或由于萬(wàn)向節(jié)上的軸承密封不好，導(dǎo)致軸承早期失油以及防塵罩材料不耐 低溫，油封唇口在冬季寒冷氣候下產(chǎn)生老化裂紋，使?jié)櫥缙诹魇?。另外，萬(wàn)向節(jié)總成在運(yùn)行中因缺油而產(chǎn)生高溫，使軸承與軸徑咬死，致使?jié)L針折斷以及密封和防塵外罩損壞，套圈表面有燒蝕痕跡，這種失效形式均屬于非正常失效形式。 4.滾針失效 從萬(wàn)向節(jié)總成失效樣品中觀察發(fā)現(xiàn)，大多數(shù)滾針表面都存在麻點(diǎn)、麻坑和大面積疲勞剝落，