直粘型胶垫气门嘴

1　传统工艺胶垫气门嘴的缺陷( 1 )内胎生产厂必须自行生产胶垫气门嘴与内胎胎身粘合用胶浆 ,需要配备打浆、干燥板及烘箱等设备 ,还需配备打浆和涂浆等人员。( 2 )在内胎挤出与硫化生产环境中 ,胶垫气门嘴很容易受到水、汽和隔离粉尘等的污染 ,对内胎的产品质量有着很大的影响。( 3)刚涂过胶浆的胶垫气门嘴 ,由于受到汽油的浸润 ,胶垫气门嘴底座边缘向外翻出 ,如果干燥停放时间短 ,易引起与内胎胎身粘合处边缘弹开 ;如果干燥停放时间过长 ,则胶垫气门嘴失去与内胎胎身的粘合性 ,必须重新涂浆和干燥 ,反复数次后 ,胶垫气门嘴底部胶层增厚 ,…     

内胎气门嘴胶垫压合器的设计与使用

根据内胎气门嘴胶垫边部慢漏气和边缘翘起的现象,对现行工艺进行了改进,设计了简便式气门嘴胶垫压合器。本文对简便式气门嘴胶垫压合器构造和安装使用以及工作原理进行了详细介绍。通过对比成品气门嘴胶垫与胎身粘合强度试验表明,通过使用简便式气门嘴胶垫压合器,提高了气门嘴胶垫与内胎胎身的粘合力并解决了气门嘴胶垫边部慢漏气与粘合力不匀的现象,同时降低了操作工的劳动强度。     

12.00R20 丁基内胎气门嘴胶垫边缘开裂的市场问题分析及处理措施

该文介绍了 12.00R20 丁基内胎气门嘴胶垫开裂问题的原因及解决措施.市场问题:因装配不到位或内胎过度伸张导致内胎气门嘴胶垫伸张度最大的点与垫带屈挠位置接触,导致气门嘴胶垫开裂.解决措施:采用正确的装配方式,保证气门嘴杆两侧相对于气门嘴杆两侧内胎伸张一致;涂抹润滑剂使内胎在装配后充气时均匀伸张,保证其某一部分不会受...     

内胎气门嘴胶垫胶料配方的研究

为提高 9 0 0 - 2 0 1 4ＰＲ斜交轮胎的ＮＲ内胎气门嘴胶垫的物理性能和粘合性能 ,我们对气门嘴胶垫的胶料配方进行了研究。现将研究情况简介如下。1　性能指标( 1 )混炼胶性能 :威氏塑性值　 >0 4,焦烧时间 ( 1 43℃ )ｔ1 0 　≥ 4 5ｍｉｎ。( 2 )硫化胶性能 :拉伸强度　≥ 2 0ＭＰａ ;扯断伸长率　≥ 5 0 0 % ;邵尔Ａ型硬度　 ( 5 7± 3)度 ;密度　 <1 35Ｍｇ·ｍ- 3。( 3)成品性能 :胶垫 黄铜气门嘴粘合强度　≥ 0 35ＭＰａ ;胶垫色泽与内胎匹配 ,打磨时边缘不产生豁口。( 4 )成本 :胶料成本不超过 5 96元·ｋｇ- 1 。2　配方设计( 1…     

影响内嘴胶与气门嘴附着力的因素及改进措施

分析指出影响内嘴胶与气门嘴附着力的因素主要有气门嘴处理及保存、内嘴胶料配方及质量波动、内嘴胶垫硫化控制、工艺操作及生产环境、内嘴胶垫固定及内胎硫化等方面,通过采取妥善处理及保存气门嘴、控制内嘴胶料配方及质量波动、稳定内嘴胶垫硫化条件、严格工艺操作及环境保持、内嘴胶垫固定及内胎硫化满足工艺条件等措施,可以提高内嘴胶与气门嘴的附着力,保证内胎质量。     

内胎气门嘴胶垫裂口原因分析及解决措施

从半成品尺寸、工器具及工艺等方面对载重内胎气门嘴胶垫裂口原因进行分析,并提出相应解决措施。通过采取调整胶垫部位胎筒厚度、控制胶垫周向与径向的厚度均匀性、调整模具与半成品宽度的伸张系数以及修改模具排气线等措施,有效解决了内胎气门嘴胶垫裂口问题。     

内胎气门嘴回收再利用工艺改进

内胎为薄橡胶制品,在生产过程中不可避免地产生一些废次品,不能与外胎配套,但其气门嘴是完好的,可回收利用这些气门嘴重新用于内胎生产。我公司曾对内胎气门嘴的回收再利用进行了一些试验,但所回收的气门嘴外观质量较差,气门嘴底座与胶垫的粘合强度较低,需要经过一定的再利用处理方可使用。     

轮胎的管理、使用和保养讲座第2讲轮胎气门嘴

随着汽车工业的发展 ,轮胎的结构、制造技术及性能不断改进和提高 ,轮胎气门嘴的结构和种类也在不断变化和发展。通常轮胎气门嘴分为两大类 :一是内胎气门嘴 ,为内胎的组成部件之一 ,由气门嘴主体带金属底座 (包括胶垫和垫片 )、六角螺母、气门芯、防护帽等零件组成。二是无内胎气门嘴 ,由金属底座、橡胶垫圈、六角螺母、金属主体接头、气门芯和防护帽等零件组成。另外 ,还有一种包管式葫芦形无内胎气门嘴可直接安装在轮辋孔位上。通过轮胎气门嘴给轮胎内胎和无内胎轮胎充气、密气、放气 ,使轮胎在各种不同使用要求下保持所需的压力。1　轮…     

丁基胶内胎胶垫与气门嘴的粘合

1.影响丁基胶内胎与气门嘴的粘合性能的因素主要有下列几条: ①胶垫含胶量;②气门嘴用黄铜的成份;③炭黑的粒径大小;④软化剂用量;⑤金属氧化物用量;⑥金属的表面处理情况。 2.提高丁基胶内胎与气门嘴粘合性能应采取下列措施:     

23.1-26低断面振动压路机轮胎设计及改进

介绍23．1—2614PR振动压路机轮胎的技术性能要求、结构设计和施工设计。据此设计，轮胎成品充气尺寸、各项性能指标完全达到设计要求。采取增大气门嘴底座直径、气门嘴底座打孔、内胎气门嘴胶垫上加贴锦纶帘布等措施后，气门嘴脱落问题大大减少，达到了预期效果。     

Elastic stresses in an adhesively-bonded functionally-graded tubular single-lap joint in tension

In this study, the elastic stress analysis of an adhesively-bonded tubular lap joint with functionally-graded Ni-Al₂O₃ adherends in tension was carried out using a 3D 8-node isoparametric multilayered finite element with 3 degrees-of-freedom at each node. Stress concentrations were observed along the edges of both outer and inner tubes in the overlap region. Thus, the outer tube region near the free edge of the inner tube and the inner tube region near the free edge of the outer tube experienced considerable stress concentrations. Normal σ_zz and shear σ_rz stresses were dominant among the stress components. In addition, both edges of the adhesive layer experience stress concentrations, and the von Mises σ _eqv stress decreases uniformly across the adhesive thickness at the free edge of the outer tube, whereas it increases at the free edge of the inner tube. However, different compositional gradients had only a small effect on the through-the-thickness normal and shear stress profiles of both outer and inner tubes, and the peak von Mises σ _eqv stresses occurred inside the tube walls. As the ceramic phase in the material composition of the outer and inner tubes was increased, peak von Mises σ _eqv stress appeared in the ceramic layer. However, its magnitude was increased 1.75-fold in both tubes. In addition, the peak adhesive stresses appeared at the edge of the outer tube–adhesive interface near the free edge of the inner tube and at the edge of the inner tube–adhesive interface near the free edge of the outer tube. Increasing the ceramic phase in the material composition caused 1.22–1.67-times higher von Mises stresses along the free edges of the adhesivetube interfaces. In addition, with increasing number of layers across the inner and outer tubes the profiles of the normal σ_zz , shear σ_r and von Mises σ _eqv stresses across the tube walls and adhesive layer become similar. Increasing the ceramic phase in the material composition of the tubes causes also evident increases in the normal σ_zz and von Mises stresses while it does not affect their through-the-thickness profiles. However, it affects only shear σ_r and von Mises stresses across the adhesive layer. Finally, the layer number and the compositional gradient do not affect considerably through-the-thickness normal and shear stress profiles but levels in a functionally graded plate subjected to structural loads.     

非金属密封垫片应力场的数值模拟

为研究聚四氟乙烯密封垫片的应力分布规律,根据有限元理论,建立了管法兰连接有限元模型。研究了垫片在预紧状态和工作状态下的Von Mises应力和接触应力分布,分析了管道内流体压力、螺栓预紧力和垫片材料弹性模量对其应力值和应力分布的影响。结果发现:垫片在工作状态下的Von Mises应力大于其在预紧状态;流体压力越大,垫片和Von Mises应力越大,但是其有效接触宽度越小;螺栓的预紧力越大,垫片的Von Mises应力和接触应力越大;垫片材料的弹性模量值对垫片接触应力值的影响较小。     

1000MW超超临界锅炉低温过热器爆管原因分析

通过爆口宏观形貌分析、氧化膜堆积量射线检查、样管基体的化学成分及硬度检测、样管内壁氧化膜微观形貌及成分分析、氧化膜脱落失效机理分析,对某发电公司1000MW超超临界锅炉低温过热器爆管原因进行了深入研究。结果表明：低温过热器垂直段下弯头氧化膜堵塞引起短时过热爆管;样管完全满足国家标准或行业标准对12Cr1MoV钢的化学成分及硬度要求,低温过热器当量金属温度也远低于低温过热器壁温设计值和12Cr1MoV的抗氧化温度;大容量锅炉低温过热器管壁厚、热应力大和大容量锅炉蒸汽流速大、扰动强度高等因素共同导致氧化膜临界脱落厚度远小于小容量锅炉同管材氧化膜正常脱落厚度,增大了低温过热器氧化膜堵塞爆管的概率;在一定区域内低温过热器壁温沿炉膛宽度方向分布为中间壁温低、两侧壁温高,两次低温过热器爆管位置均在壁温最高区域,壁温高也增加了氧化膜生成速率和爆管的概率。研究结果还表明：样管内壁氧化膜有明显分层现象,由外到内分别为Fe₂O₃层、Fe₃O₄层和富Cr氧化物层等3层,晶粒尺寸由外层至内层逐渐减小,表面结构由外层至内层逐渐致密。     

A finite element analysis of the effects of residual stress,substrate roughness and non-uniform stress distribution on the mechanical properties of diamond-like carbon films

High residual stress has been a critical issue that limits the application of DLC films. The stress not only deteriorates the adhesion strength of DLC in different substrates, but also affects the measurement of mechanical properties such as hardness or elastic modulus. In this study, a two-step finite element analysis that simulates the pre-stress induced by a thermal process followed by nanoindentation was carried out to study the residual stress effects on mechanical properties. Residual stress generated by different substrates, substrate roughness and non-uniform stressing are compared based on the impact on the mechanical properties. The results show that positive residual stress tends to increase hardness and elastic modulus while negative stress generally results in a decrease in hardness and elastic modulus. Different substrates lead to different degrees of variation but not to any change in the overall trend. The degree of variation is magnified by substrate roughness. For non-uniform stress distribution, a smooth substrate has small variation in hardness and elastic modulus from center to edge and such variation is manifest in a rough substrate. These results indicate that the mechanical properties (hardness and elastic modulus) are affected by the residual stress. Factors like different substrates, substrate roughness and measurement position cause different degrees of variation in these properties. Therefore, the interpretation of mechanical properties should be applied carefully.     

承受外弯矩作用的法兰接头性能研究

采用有限元法模拟了垫片的非线性特性,计算了垫片应力及法兰应力。按应力分析设计方法校核法兰;基于PVRC紧密性的计算方法．以垫片应力为判据,关联了外弯矩与接头紧密度之间的关系。     

CNTs阵列增强石蜡/硅橡胶复合相变垫片的散热性能研究

电子技术的高速发展对散热技术提出了更高的要求,热界面材料作为散热技术的关键材料之一,面临着提高热导率以及减小传热热阻的挑战。将垂直碳纳米管阵列(VACNTs)和固-液相变材料石蜡(PA)与硅橡胶(SR)复合,研制了一种新型VACNTs/PA/SR复合相变垫片。研究表明,通过磁场校准方法可以使表面改性的镀镍多壁CNTs在SR中实现垂直定向排列,所得VACNTs/SR垫片较CNTs随机排列的垫片具有更高的热导率,并确定VACNTs/SR垫片中CNTs的适宜含量为6%(质量),对应垫片的热导率可达0.71 W/(m·K)。对于固定CNTs含量为6%(质量)但PA含量不同的一系列VACNTs/PA/SR相变垫片,PA的添加量不大于12.5%(质量)时,相变垫片克服了液态PA的泄漏问题;相变垫片在PA发生固-液相变后表现出硬度显著下降,热阻减少可达55.14%,并具备优异的热可靠性。将最佳VACNTs/SR垫片样品及最佳VACNTs/PA/SR相变垫片样品进行散热性能对比发现,与使用VACNTs/SR垫片的情况相比,使用VACNTs/PA/SR相变垫片时的模拟芯片不仅在温度上升阶段的升温速率更小,而且当芯片温度达到平衡后对应的平衡温度也更低,降低了3.5℃,显示出更好的散热性能。VACNTs/PA/SR相变垫片优良的特性和散热性能使其在电子设备散热领域具有良好的应用前景。     

CNTs阵列增强石蜡/硅橡胶复合相变垫片的散热性能研究

电子技术的高速发展对散热技术提出了更高的要求,热界面材料作为散热技术的关键材料之一,面临着提高热导率以及减小传热热阻的挑战。将垂直碳纳米管阵列(VACNTs)和固-液相变材料石蜡(PA)与硅橡胶(SR)复合,研制了一种新型VACNTs/PA/SR复合相变垫片。研究表明,通过磁场校准方法可以使表面改性的镀镍多壁CNTs在SR中实现垂直定向排列,所得VACNTs/SR垫片较CNTs随机排列的垫片具有更高的热导率,并确定VACNTs/SR垫片中CNTs的适宜含量为6%(质量),对应垫片的热导率可达0.71 W/(m·K)。对于固定CNTs含量为6%(质量)但PA含量不同的一系列VACNTs/PA/SR相变垫片,PA的添加量不大于12.5%(质量)时,相变垫片克服了液态PA的泄漏问题;相变垫片在PA发生固-液相变后表现出硬度显著下降,热阻减少可达55.14%,并具备优异的热可靠性。将最佳VACNTs/SR垫片样品及最佳VACNTs/PA/SR相变垫片样品进行散热性能对比发现,与使用VACNTs/SR垫片的情况相比,使用VACNTs/PA/SR相变垫片时的模拟芯片不仅在温度上升阶段的升温速率更小,而且当芯片温度达到平衡后对应的平衡温度也更低,降低了3.5℃,显示出更好的散热性能。VACNTs/PA/SR相变垫片优良的特性和散热性能使其在电子设备散热领域具有良好的应用前景。     

高温法兰连接结构的有限元模拟及安全评定

利用ANSYS软件分析了高温螺栓法兰连接系统在预紧、承压及热-机操作工况下的应力和变形行为,并基于强度分析和密封分析对螺栓法兰连接进行了安全评定.结果表明：不同工况下,应力具有相似的分布规律,法兰最大应力在螺母与法兰接触面的内侧,上、下法兰应力分布具有对称性;螺栓应力呈现拉弯组合形变,最大应力出现在由中间向两端第一个螺纹根部;垫片应力在各工况下均呈现为外大内小,密封面压力均大于满足密封要求的最小压紧力,法兰的转角均小于0.3°,满足法兰刚度要求,强度分析和密封分析均满足要求,具有良好的紧密性,给出了一种工程分析方法.     

关于气雾剂产品抛射剂与内垫圈搭配的探讨

气雾剂抛射剂主要是通过气雾剂阀门泄漏，气雾剂抛射剂泄漏与气雾剂阀门内垫圈材质存在一定关系。本文通过对目前比较通用的气雾剂抛射剂与几种常见的气雾剂阀门的内垫圈材质进行相容性测试，优选出一组最佳搭配，可以有效减少气雾剂抛射剂的泄漏量；可消除气雾剂在生产、储运、使用过程中因抛射剂泄漏而造成的安全隐患，提高气雾剂产品的安全性。     

cBN–TiC and WC–Co Composites: Optimization of Co‐Extruding Conditions

In this study, double‐layer tubes with inner‐layer cubic boron nitride–titanium carbide (cBN–TiC) and outer‐layer tungsten carbide–cobalt (WC–Co) were fabricated by co‐extrusion. The Taguchi method was used to determine the optimal parameters, including extrusion ratio, half‐die angle, extrusion speed, and binder amount. The double‐layer tube made using these optimal parameters had an inner‐layer hardness of 3825 Hv and an outer‐layer hardness of 1849 Hv. The porosity of the double‐layer tube was 10.4%. Furthermore, the crystalline structures obtained from the inner and outer layers were cBN, TiC, TiB₂, and BNi and WC and Co₂C phases.