基于H-T对数修形下圆锥滚子轴承整体接触应力分析

圆锥滚子轴承能够承受较高的轴向和径向载荷，同时也可以支撑一定的力矩载荷。为获得具有更好承载能力圆锥滚子轴承，考虑对圆锥滚子轴承滚子采用H-T对数修形，并对整个圆锥滚子轴承在承受轴向、径向以及力矩载荷作用下建立整体接触分析的数学模型。根据变形协调以及力平衡条件并利用MATLAB编制程序对圆锥滚子轴承的整体平衡方程进行求解。最后，通过实例验证，对修形前后圆锥滚子轴承的接触应力进行对比分析。     

用电焊切割圆锥滚子轴承外圈

用电焊切割圆锥滚子轴承外圈（５３５３００）广西上思县农机校谭影航圆锥滚子轴承一般内圈装在轴上，外圈装在轴承座或轴承盖上，都是过渡配合．在使用中，由于润滑条件的限制与密封住下降，容易飞进尘土和漏入水蒸汽，造成外圈和轴承座（盖）生锈而粘结，配合很紧．在没...     

门式起重机大车过渡轮轴的改进

本文就现行林用龙门起重机固定死的过渡轮轴由于润滑不合理,经常停机检修影响生产,提出一种两端用圆锥滚子轴承固结的活动轴。结构简单、合理,便於拆装,效果良好。     

197717型森铁专用轴承

1980年,牡丹江林机厂在设计HZ1型森铁货车转向架时,选用了无轴箱双列圆锥滚子轴承,并自制外套加装密封装置。虽然试运情况良好,但轴承组零件加工、组装均很困难,不易保证质量。1982年5月与大连机床附件厂签订了197717型森铁专用无轴箱轴承试制协议书,于年末试制     

全国人造板标准一览

一、现行的我国人造板标准1纤维板难燃中密度纤维板GB/T18958-2003中密度纤维板GB/T11718-1999薄型硬质纤维板LY/T1205-1997浮雕纤维板LY/T1204-1997硬质木纤维瓦楞板LY/T1203-1997硬质纤维板GB/T12626-1990地板基材用纤维板LY/T1611-20032刨花板刨花板GB/T4897.1~4897.7-2003石膏刨花板LY/T1598-2002定向刨花板LY/T1580-2000模压刨花制品(家具类)GB/T15105-1994船用贴面刨花板LY/T1057-19913胶合板胶合板GB/T9846.1~9846.8-2004集装箱底板用胶合板GB/T19536-2004竹编胶合板GB/T13123-2003汽车车厢底板用竹材胶合板LY/T…     

森铁重型台车轴承改造技术

介绍了森铁重型台车上改装导框式无轴箱圆锥滚子轴承的结构、技术指标的测试及经济效果的分析。这种改装,具有结构简单、工作安全可靠、使用寿命长、维修保养方便、牵引效率高、综合经济效益好等特点。     

第3期GB 18580-2017宣贯培训会举办

<正>近日,第三期GB 18580-2017《室内装饰装修材料人造板及其制品中甲醛释放限量》宣贯培训会在江苏常州举办。会议特邀GB/T 31745-2015《高耐磨漆饰实木地板》和GB/T 17657-2013《人造板及饰面人造板理化性能试验方法》的负责起草人,分别对GB/T31745-2015、GB 18580-2017、《甲醛释放量检测方法1立方米气候箱法》(GB/T 17657-2013的4.60)进行     

《浸渍纸层压秸秆复合地板》等国标即将实施

正根据《中华人民共和国国家标准批准发布公告》(2018年第9号),经国家市场监督管理总局和国家标准化技术委员会批准,GB/T 234711-2018《浸渍纸层压秸秆复合地板》、GB/T 36407-2018《机械应力分级锯材》、GB/T 36408-2018《木结构用单板层积材》和GB/T 117177-2018《造纸用原木》等四项国家标准,将     

国标《细木工板》和《集装箱底板用胶合板》宣贯

<正>近日,GB/T 5849-2016《细木工板》和GB/T19536-2015《集装箱底板用胶合板》宣贯会在厦门召开。来自企业、质检和科研等单位的80名代表参会。会议特邀GB/T 5849-2016和GB/T 19536-2015的主要起草人,分别对两项标准进行了详细解读和答疑;厦门市产品质量监督检验院的专家,做题为     

两项竹材物理力学性质试验方法标准的比较

对比两项竹材标准,JG/T 199-2007<建筑用竹材物理力学性能试验方法>和GB/T 15780-1995<竹材物理力学性质试验方法>,在发展历程、试样制备、物理力学性质测试设备与方法等方面进行综合比较,以期为GB/T 15780-1995下一步的修订工作提供参考.     

滚筒式马铃薯清洗机的设计研究

本文对滚筒式马铃薯清洗机的设计进行了研究 ,并对实际使用中反馈的信息进行分析 ,进一步完善了滚筒式马铃薯清洗机的设计。     

Spatial genetic structure in populations of the green oak leaf roller, Tortrix viridana L. (Lepidoptera, Tortricidae)

The green oak leaf roller (Tortrix viridana L.) is a major pest on oaks. The green oak leaf roller is one reason within a disease complex for the oak decline, and it leads to defoliation of oaks in spring. In Germany, Quercus robur L. is mainly affected. The partitioning of genetic variation within and among populations of forest pests is linked to their capacities for migration. And the capacity for migration is the basis for dispersal of the pest species to different host trees and host populations and, therefore, for further outbreak events. Thus, the within population spatial genetic structure (SGS) of T. viridana was investigated based on nuclear (AFLP) markers to analyse the dispersal capacity of this insect pest species at a very small spatial scale. A total of 401 individuals of the green oak leaf roller from four stands in North Rhine-Westphalia (Western Germany) were examined. In three of four populations, the AFLP markers revealed clearly SGS up to 40 m, which can be explained by the mating behaviour within this species.     

无振动"行星"托索轮的研究

现行各种索道的载运车通过托索轮的过程中 ,必然有一个突然被向上提升并立即被下跌失重的不良感觉 ,同时由于载运车抱索器的尺寸一般大于承载索的直径 ,必然冲击托索轮沿而出现一次振动 ,由此容易造成钢丝绳的出轨和掉斗的问题。针对这个问题 ,研制了一种让索道的载运车通过一种新型的无振动托索轮时 ,不产生向上冲击的力量 ,也不产生振动 ,从而使客运索道的乘客感觉平稳舒适。     

木门门扇边部垂直辊涂工艺技术

研究木门门扇边部垂直辊涂工艺及设备,重点分析其砂光单元、辊涂单元和干燥单元的结构和工作原理;以2道腻子3道底漆垂直辊涂为例,介绍了木门门扇边部垂直辊涂工艺的涂饰流程和参数特征。     

Genetic structure of the green oak leaf roller (Tortrix viridana L.) and one of its hosts, Quercus robur L.

An herbivorous insect, the green oak leaf roller (Tortrix viridana) and one of its host species, pedunculate oak (Quercus robur), were investigated for their genetic variation within and among populations on the basis of mitochondrial, chloroplast, and anonymous markers. Oaks and green oak leaf rollers from 10 oak stands in North Rhine-Westphalia (North-Western Germany) were examined. The genetic variation of pedunculate oaks is much lower within than among populations when assessed using chloroplast gene markers and higher among populations when assessed using anonymous markers. When using mitochondrial and AFLP markers, the genetic variation of the green oak leaf roller populations was higher within than among the populations, which suggests a high gene flow between the populations. Mantel tests on the gene diversities of oaks and the green oak leaf roller yielded a significant negative correlation for both marker types. To sum up, the reasons for the differences in the spatial patterns of the genetic variation of the host and herbivorous insect may be found in their different generation times, mechanisms and capacities for dispersal.The results for the green oak leaf roller revealed a higher migration rate than assumed before which has consequences for the prediction of the dynamics of future outbreak events.     

Avian community response to pine flatwoods management

Across the southeastern United States, changing disturbance regimes threaten the integrity of pine flatwoods, reducing their suitability as habitat for a variety of avian species, many of which are considered of conservation priority. Prescribed burning and roller chopping are management practices widely used in pine flatwoods to control shrubs and increase the growth of herbaceous vegetation. However, the impacts these treatments have on this system and its associated avian communities are largely unknown. We examined the effects of prescribed burning and roller chopping on pine flatwoods avian communities using a paired sample approach. Avian communities were compared between treated (e.g., burned) and untreated areas. We considered abundance and richness of all birds, but also groups of conservation concern, and those likely impacted by seasonal management practices (e.g., breeding and non-breeding categories, and woodland, successional-scrub, and grassland guilds). Dormant season burning resulted in decreases in avian species richness and abundance within the non-breeding, overwintering community. In situations where the maintenance or enhancement of this avian group is desired, growing season burning appears beneficial and should be used in preference to dormant season burning. Growing season burning benefited breeding avian communities, resulting in increases in species richness and abundance within this group. Dormant season roller chopping had no effect on species richness or abundance of any avian category or guild. Increases in abundance within breeding avian communities were observed following growing season roller chopping and a roller chopping/burning combination. Grazing, did not mediate the effects of prescribed burning or roller chopping on avian species richness or abundance. The use of dormant season burning is likely inappropriate in situations where conservation and management of non-breeding, overwintering species is a priority. The use of growing season roller chopping appears to provide a potential treatment alternative in situations where positive effects on breeding species are desired. Overall, maintenance of avian abundance and richness may be best achieved through the diverse application of prescribed burning and roller chopping based on season, frequency, and space.     

过山车轨道三维建模方法研究

着重介绍了过山车轨道的三维建模方法,通过该方法可以建立准确的过山车轨道三维模型,为以后对过山车进行动态仿真以及运动学和动力学分析打下基础,有效提高过山车的安全性能。     

基于Solid Edge的不锈钢圆筒形件拉深模具设计的研究

分析了不锈钢在拉深中存在的工艺问题和如何选用模具材料以延长模具的寿命。并基于Solid Edge平台，采用参数设计技术和Visual Basic工具，开发了一个圆筒形零件拉深模具系统，该系统能够全参数化进行零件设计并生成零件图、模具虚拟安装并生成模具装配图。     

园林硬质景观施工图的表现方法

园林施工图是园林设计意图的最终表现形式,也是建设单位进行成本控制与组织施工的依据.园林施工图通常分为硬质景观(园建)施工图、软质景观(绿化)施工图、给排水施工图和电气施工图几个专业,各专业一般分别按单独系统出图.本文主要探讨硬质景观施工图的表现方法.     

浅谈MR417型带锯机压辊技术

压辊是ＭＲ４１７型带锯机的关键配件，它直接影响着制材的质量，该就压辊技术作以探讨。