滑动轴承-薄壁翻边轴瓦尺寸公差及检验方法

1、适用范围 本标准规定了用于往复运动机械上的薄壁翻边轴瓦的主要尺寸和公差。虽然并不要求所有翻过轴瓦的主要尺寸都采用本标准规定的尺寸,但采用标准尺寸可以降低加工成本。 本标准规定了适用于轴承座孔内径为40～250mm的翻边薄壁轴瓦的主要尺寸和公差。轴承座孔尺寸再大或再小的翻边轴瓦很少使用,所以这里不作规定。 本标准规定了薄壁翻边轴瓦结构要素尺寸和公差。但在结构设计中,是否采用这些结构要素由用户根据自己的使用知识来决定。 翻边轴瓦的使用场合一般与1SO3548规定的不带止推边轴瓦相似。 另外,用不带止推边的轴瓦加上两个半圆止推片就可以代替翻边轴瓦。其技术要求根据ISO3548和ISO6526由供需双方协商。 注:除另有说明,本标准中所有尺寸和公差的单位都是mm.     

汽车发动机用翻边滑动轴承

1适用范围 本标准是对汽车发动机用主轴承（以下简称轴瓦）中,关于翻边轴瓦主要尺寸及允许偏差的规定。备注 本标准除标准规格轴瓦外,也适用于加大规格轴瓦的主要尺寸及与其密切相关的尺寸。2尺寸、公差及允许偏差2.1轴瓦部位的尺寸、公差及允许偏差2.1.1轴瓦厚度:     

滑动轴承-薄壁轴瓦尺寸、公差和检验方法

一、前言 本标准规定了薄壁轴瓦的主要尺寸和公差,虽然不希望所规定的尺寸都采用,但采用标准尺寸可降低加工成本。 对每个轴承座尺寸,本标准提出了壁厚尺寸范围,以便能按照设计的需要选择轴颈的尺寸。 薄壁轴瓦的某些尺寸和公差,由于其特殊性而不能直接测量。因此在第6节中规定了检验这些尺寸与公差的方法。 2、适用范围 本标准适用于轴承座孔内径为20～500毫米的往复运动机器中的薄壁轴瓦。 本标准规定了轴瓦的一般结构要素,但在特殊设计中,是否采用这些结构要素由用户根据自己的使用知识决定。 3、参考标准 ISO3547滑动轴承-卷制轴套的尺寸、公差和检验方法。     

国际标准 滑动轴承─薄壁翻边轴瓦的尺寸公差和检验方法

1.适用范围 本国际标准为用于往复机械的薄壁翻边轴瓦规定了主要尺寸范围和公差。不能期望从毛坯开始所有表列的主要尺寸都是有用的,但选用标准尺寸能使加工装置成本降低。 本标准所规定的一系列薄壁翻边轴瓦的主要尺寸和公差,适用于轴承座孔(内径)直径为40～～250mm的轴瓦,很少用于较大或较小内径的翻边轴瓦。 本标准对薄壁翻边轴瓦的特定部位也规定了尺寸和公差。对某一部位采用特殊的设计取决于使用者的经验。     

日本工业标准 汽车发动机滑动轴承

1适用范围 本标准是对汽车发动机主轴承和连杆轴承（以下简称轴瓦）中,关于不带边轴瓦的主要尺寸及允许偏差的规定。 注:本标准除标准规格轴瓦外,也适用加大规格轴瓦的主要尺寸及与此有关部分的尺寸。2尺寸、公差及允许偏差2.1轴瓦的壁厚 轴瓦的壁厚,规定如下:（1）轴瓦壁厚的标准尺寸,规定在表1中用O表示。     

薄壁轴瓦冲压成形凹模设计

目前轴瓦冲压成形凹模都是采用整体形式（图1）。我们在生产中发现,一般冲刺1～2万片轴瓦时轴瓦的贴合度还可以保证,但冲刺3～4万片就很勉强了。凹模的尺寸公差。形状公差和表面粗糙度等级要求很高,加工凹模工艺复杂,生产一个合格凹模是很费工耗时的。如有时淬火硬度不够。冲制几千片轴瓦就不行了;有时内孔加工达不到要求而造成冲制的轴瓦贴合度不合格。     

曲轴主轴颈中心油孔加工方案研究及验证

某高速机曲轴结构复杂、长径比较大;轴中心油孔在曲轴中心线上,长度贯穿整个曲轴,直径小;油孔全长直线度要求及表面粗糙度要求高。经对曲轴油孔技术要求及加工难点的分析并结合现有设备能力,制定了合理的加工工艺方案,并设计了专用找正钻模和专用镗头,实现了普通深孔钻镗床的曲轴深孔加工。     

S195主轴瓦止推边与筒体采用摩擦焊工艺时,防止锡“冒汗”的试验研究

S195主轴瓦止推边与简体采用摩擦焊接工艺,由于摩擦焊过程中原始接触表面的移动大小不一,形成了一定的塑性区。这个塑性区在轴向推力的作用下很容易产生塑性变形。而较大的塑性变形引起20锡铝合金的“冒汗”。这将破坏20锡铝合金的减磨合金成分。     

主轴承翻边变薄问题探讨

195柴油机主轴承冲压翻边工艺,是目前轴瓦行业普遍采用的工艺,它较之摩擦焊边、冲压镶边、压铸铝边等工艺,具有效率高,成本低,废品率低等优点.用AlSn20Cu—钢材料,采用冲压成型的方法,整体制作195主轴承,碰到的最大难题是止推边达不到要求厚度,边沿合金层变薄.这是由于冲压翻边的特殊工艺造成的,翻边时在翻边力的作用下,止推边产生弯曲变形,上表面存在拉应力,下表面存在压应力,同时在周向拉力的作用下,还     

内燃机精密电镀减摩层轴瓦检验标准编制说明

一、任务来源及制订目的 本标准是遵照机械工业科学技术发展计划第85410217项的任务而编制。 现代中小功率内燃机不断向高速、高负荷方向发展,因而主轴瓦和连杆轴瓦均需采用较高强度材料,凡应用此档轴承材料必须改善其与曲轴匹配的性能,即主轴瓦和连杆轴瓦工作表面精密电镀减摩合金层。该减摩层作为走合缓冲层,提高轴瓦的适应性和对脏污微粒的嵌入性能,减少曲轴的磨损和拉伤,特别是发动机在高速运转时或润滑油不足时,可防止产生咬轴现象发生,从而大大延长了轴瓦使用寿命。为此,我国轴瓦行业近几年,从国外引进了精密电镀减摩层工艺,有的生产厂与研究所联合,共同开发此技术。当前主机厂要求使用镀层轴瓦也越来越多,为了适应这一需要,必须建立一项检验标准,使镀层轴瓦制造厂有一个控制产品质量的技术依据,主机厂装机使用有一个检验规定。本标准制订将为我国轴瓦行业技术进步,发挥积极作用。     

发动机横隔板三维有限元分析

用ABAQUS软件进行了发动机横隔板的强度及疲劳分析.分析模型包括机体、主轴承盖、轴瓦、主轴承盖螺栓、假体缸盖、缸盖螺栓.应用接触非线性分析方法,对机体横隔板进行装配、最大爆发压力工况和最大惯性力工况下的强度和疲劳求解计算.     

现代汽车发动机制造工艺的发展动向

本文叙述了发动机五大件加工工艺的发展动向：缸体与缸盖正在发展敏捷柔性生产线取代传统柔性生产线;曲轴的主轴颈和连杆颈的粗加工工艺已由车拉（含车一车拉）、内铣、单刀车削（转塔式）及高速外铣取代了过去多刀车削及普通内铣,并提出了怎样合理选用车拉、内铣、单刀车削及高速．外铣工艺;凸轮轴的凸轮磨削已由 ＣＮＣ无靠模磨削工艺取代了过去机械式靠模磨削工艺;凸轮轴（含曲轴）的主轴颈系统磨削工艺正在发展由高速点磨工艺取代传统磨削工艺,同时最近又开发出凸轮轴（含曲轴）的主轴颈系统和凸轮（曲轴的连杆颈）的集成磨削工艺;连杆分离面正在采用涨断工艺取代传统切削工艺。     

钢套筒混凝土压力管道内水压承载性能有限元分析

为了研究新型结构钢套筒混凝土压力管道(SSCP)的内水压承载性能,建立SSCP非线性有限元模型,通过施加管道自重、管道内水重和逐级增大的均匀内水压力模拟SSCP从生产到运行各个阶段的受力状况,得到各工况下SSCP的应力变化特点和塑性开展规律。结果表明,SSCP在内水压力较小、未达到开裂压力Pb的工况下处于完全弹性状态,各构件应力均能满足正常工作要求,安全度较高。随着内水压力的增加,达到Pb后,管底混凝土管芯内表面最先出现塑性并不断沿轴向和管腰方向扩展。在施加内水压力过程中,内层钢筒承担的拉应力大于外层钢筒。     

FRACTURE OF THICK-WALLED CYLINDERS SUBJECTED TO TRANSIENT THERMAL STRESSES

In this paper, the fracture problem of a thick cylinder subjected to transient thermal stresses is considered. The problem has practical significance in the conventional and nuclear power industries where the structural integrity of components may be damaged due to sudden temperature changes. Neglecting the inertia effects, the thermal fracture problem is uncoupled. First the thermal stresses in a thick cylinder due to a sudden change in temperature are computed separately as a function of time. Then, these stresses are used as external loads in analyzing the fracture of a thick cylinder. The assumed crack, may be an inner edge crack, outer edge crack or an embedded crack. Extensive results are obtained by varying the parameters of the problems. The main parameters affecting fracture are identified and the results are discussed in some detail.     

Influence of relative motion of magnetic field on time‐dependent MHD natural convection flow

The effects of relative motion of magnetic field on unsteady magnetohydrodynamic free convection flow with ramped motion and temperature‐dependent heat source/sink have been analyzed. The motion of the inner cylinder is ramped while the motion of the outer cylinder is fixed. The momentum and energy equations are solved using the well‐known Laplace transform. The time‐domain solution is obtained using the Riemann‐sum approximation method. The influence of the governing parameters on fluid velocity, fluid temperature, volume flow rate, and rate of heat transfer are discussed with the help of line graphs. It is found that Hartmann number has a retarding effect on fluid velocity, skin friction at the outer surface of the inner cylinder, and mass flow rate when the magnetic field is fixed with the fluid and when the velocity of the magnetic field is less than the velocity of the moving cylinder. Whereas, the reverse effect is noticed when the magnetic field is fixed with the moving cylinder.     

Inner cylinder diameter effects on free convection heat transfer in a stable stratified fluid

An experimental study was performed to identify the effects of the inner cylinder diameter on free convection heat transfer in a stable stratified fluid between coaxial cylinders. The stratified layer was formed using a sucrose aqueous solution, and was heated from the outer cylinder (70 mm I.D.) at a constant heat flux and cooled from the inner cylinder at a constant temperature. The experiment was conducted for an inner cylinder of 50.8 mm O.D. and the results were compared with those for an inner cylinder of 30 mm O.D., which were previously reported by the authors. The results show that the inner cylinder size affects the heat transfer in the early stage of heating: increasing the diameter of the inner cylinder decreased the distance between the heating and cooling surfaces. It consequently reduced both the duration of heat conduction prevailing and the resulting temperature increase of the heating surface during that period. Increasing the diameter of the inner cylinder also made the heat transfer characteristics similar to those between vertical plates. © 2007 Wiley Periodicals, Inc. Heat Trans Asian Res, 36(3): 172– 186, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20148     

增压中冷柴油机主轴承润滑特性研究

基于弹性流体动力润滑理论,建立了4缸柴油机主轴承润滑仿真模型,研究了不同转速下内燃机轴瓦与轴承座的弹性变形、轴瓦与轴颈粗糙度对主轴承润滑特性的影响。研究结果表明:5个主轴承膜厚比均大于1,其中第5主轴承峰值油膜压力与其他4个主轴承相比明显偏大,而且存在偏磨现象,润滑相对恶劣;优化后第5主轴承峰值油膜压力平均降低了20%,最小油膜厚度平均增加了25%,摩擦功耗平均降低了43%。     

A criterion-selection diagram for the thermal shock resistance of a hollow circular cylinder

Abstract

The characteristics of thermally induced failure are investigated for a hollow circular cylinder exposed to a convective cooling at the inner surface. The transient fields of both temperature and thermal stresses are given in closed forms over the full range of Biot number. The thermal shock resistance (TSR) is analyzed based on two distinct failure criteria. Namely, the strength-based failure criterion is adopted for a nearly flaw-free cylinder while the fracture toughness-based one is used for the counterpart with an inner crack-like flaw. From each criterion, the admissible maximum temperature drop is obtained assuring that a hollow cylinder can tolerate without failure. The influence of flaw size on the TSR is quantified and a criterion-selection diagram is proposed for the TSR characterization. These results are deemed to be of importance from the perspective of estimating the TSR of a hollow circular cylinder.     

Numerical investigation of the three-dimensional natural convection inside horizontal concentric annulus with specified wall temperature or heat flux

A numerical investigation for three-dimensional natural convection inside horizontal concentric annulus with open ends and conditions of either adiabatic or isothermal outer cylinder surface is made by a zonal grid approach, which extends the outlet boundary from the open end of the annuli to a far enough outside position that can be reasonably specified with the ambient flow properties. Computational result reveals that the maximum inner cylinder surface temperature occurs right at the top of the inner cylinder. It is also found that the inner cylinder surface temperatures decrease towards the outlet plane for the adiabatic case, while remains relatively constant for the isothermal case. The variation of the inner cylinder surface temperatures is smaller for the isothermal case as compared to the adiabatic case.