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_投影 projection投影中心center of projection投影面projecting plane投影线projecting line中心投影法perspective projection平行投影法parallel projection斜投影oblique projection正投影orthographic projection正投影面frontal plane of projection侧面投影面profile plane of projection投影图projection drawing三面投影图three-plane projection drawing投影轴axis of projection投影特性characteristic of projection不变性characteristic of true积聚性characteristic of concentration类似性characteristic of similarity视图view三视图three-view drawing正面frontal plane正面投影frontal projection水平面horizontal plane水平投影horizontal projection侧面profile plane侧面投影profile projection主视图frontal view俯视图top view左视图left side view立体solid平面立体plane body曲面立体body of curved surface回转面surface of revolution棱柱prism棱锥pyramid边side顶点center vertex棱edge点point直线line straight line棱锥台truncated pyramidfrustum of pyramid重影coincidence of projection积聚concentrate变形deformation实长true length实形true shape正平线frontal line水平线horizontal line侧平线profile line一般位置直线oblique line铅垂线vertical line, frontal-profile line正垂线horizontal-profile line侧垂线frontal-horizontal line一般位置平面oblique plane相交intersection平行parallel垂直perpendicular交线intersecting line, line of intersection交点point of intersection平行线parallel line垂直线perpendicular line交叉线skew line长度length宽度width高度height组合体complex基本几何体basic body相接built-up相交inter section相切tangent相贯penetration支架brace底板bottom board肋rib支承板bearing plate轮廓线outline, contour line底图traced drawing截平面cutting plane截交线line of section二重性dual nature平面曲线plane curve圆弧arc椭圆ellipse长轴major axis短轴minor axis双曲线hyperbola抛物线parabola圆circle圆锥顶conic apex相贯体intersecting bodies相贯线line of intersection空间曲线space curve截平面方法cutting plane method辅助面auxiliary surface辅助平面auxiliary plane最高点culminating point尺寸Size定形尺寸size dimension定位尺寸location dimension左视图right view后视图rear view, back view仰视图bottom view辅助图auxiliary view局部视图partial view, broken view斜视图oblique view旋转视图revolved view, aligned view剖视图sectional view, section全剖视full section半剖视half section局部剖视图partial section, broken-out section斜剖视图oblique section旋转剖视图aligned section阶梯剖视echelon section, offset section复合剖视compound section剖面图section, sectional view重合剖面coincide section, revolved section移出剖面removed section剖面线section line剖面符号symbols for section-lining习惯画法conventional drawing局部放大图 drawing of partial enlargement零件图detail drawing, working drawing第三角投影third angle projection粗实线continuous thick line, full line, visible line细实线continuous thin line虚线dot line, dashed line, hidden line点划线dash and dot line双点划线double dots line波浪线break line断裂线剖切平面迹线cutting plane line尺寸线dimension line尺寸界线extension tine尺寸dimension size箭头arrowhead基准datum基准线datum line基准面datum plane中心孔central hole中心距center distance轴shaft, axle孔hole斜孔inclination装配图assembly drawing性能尺寸characteristic dimension大小尺寸size dimension总体尺寸outer dimension外形尺寸配合尺寸fit dimension内圆角fillet外圆角round尖角sharp corner倒角chamfer轮缘flange of wheel缘、边、环rim轴肩shoulder凸台boss凹坑concave pit轴颈shaft neck轮毂hub轮辐spoke, spoke of wheel直纹滚花straight knurling s网纹滚花hatching knurling键槽key-way退刀槽escape拔模斜度pattern draft填料盒gland box油槽oil groove油封oil seal标准件standard parts螺纹thread外螺纹external thread内螺纹internal thread大径major diameter小径minor diameter螺距pitch of thread牙型form of thread旋向direction of turning右旋螺纹right-hand thread左旋螺纹left-hand thread头数number of thread导程lead粗牙coarse thread细牙fin thread螺栓bolt螺钉screw螺柱stud螺母nut垫片washer公差tolerance公差带tolerance zone零线zero line标准公差standard tolerance公差等级tolerance grade基本偏差fundamental deviation配合fit间隙配合clearance fit过盈interference过盈配合interference fit过渡配合transition fit基孔制hole-basic system of fits基轴制shaft-basic system of fits间隙clearance形状公差tolerance in form, form tolerance直线度straightness平面度flatness圆度roundness圆柱度cylindricity线轮廓度profile of any line面轮廓度profile of any plane位置公差tolerance in position, position tolerances平行度 parallelism齿轮gear圆柱齿轮cylindrical gear正齿轮spur gear斜齿轮spiral gear轮齿gear tooth节圆pitch circle齿顶圆addendum circle, outside circle齿根圆root circle, addendum circle模数modulus齿数number of teeth齿高tooth height齿顶高height of addendum齿根高height of addendum齿厚circular thickness齿间tooth space齿宽tooth width压力角angle of pressure弹簧spring销pin圆柱销round pin圆锥销taper pin开口销cotter pin, split键key平键flat key半圆键half round key, woodruff key轴承bearing滚动轴承rolling bearing向心铀承radial bearing密封装置sealing equipment锁紧装置locking equipment粗糙度roughness基本尺寸basic size实际尺寸actual size极限尺寸limits size最大极限尺寸maximum limit of size最小极限尺寸minimum limit of size偏差deviation上偏差upper deviation下偏差lower deviation垂直度perpendicularity倾斜度angularity同轴度concentricity对称度symmetry位置度true position跳动run-out圆跳动cycle run-out全跳动total run-out轴测投影axonometric projection轴测投影面plane of axonometric projection轴测图axonometric drawing正等轴测投影isometric projection正二测bimetric 我先根据个人的一点经验，总结出来随便谈谈。 根据热传导的途径来说，散热相应有以下三种主要方式： 一、散热片导热式散热 1、良好接触面：要求发热件与散热片要有良好接触，尽可能降低接触热阻，所以最好有大的接触面，接触面还需要有较高的光洁度，为了弥补因接触面的粗糙而导致的贴合不良，可以在中间涂抹导热脂，可以有效降低接触热阻； 2、良好的导热材料：铜、铝都有较好的导热性能，铜的导热系数虽然优于铝，但铜有密度太高、价格贵的缺点，所以实际应用中铝材是应用最多； 3、散热片固定方式：这个也是比较重要的一环，如果不能把发热件与散热片良好接触，也是无法有效把热量传导到散热器上的，应用中有直接用螺丝钉紧固的，也有用弹簧片压固的，可以根据需要选择设计，需要说明的是，有些功率器件和散热片之间有绝缘要求，中间选用的绝缘材料就一定要选用低热阻的材料，比如：聚脂薄膜、云母片等，实际安装中还要注意固定位置应使用受力均匀分布； 4、散热片的形状：包括页片与基材的形状尺寸，要有尽可能加大散热表面积，这样散热片的热量才能快速与周围空气对流，比如说增加页片数目、在页片上做波浪纹都是好办法；基材要厚一些比较好，长而薄的散热片效率很差，在远端基本上是不起作用的了； 二、对流散热 1、自然对流：发热器件或者散热片的热量可以是依靠自然对流散热，这样的话，发热件或者散热片最好以长边取为垂直方向为佳，而且要尽量使散热片的横断面与水平面方向平行，因为热空气是上升的，这样才比较有利于空气流通，象单面页片式的散热器就比较适合安装在机体背板以自然对流方式散热； 2、强制对流：采用风扇强制吸、排的方式拉动一个风场来加强空气对流，是比较有效的散热方式，可以根据需要选择合适的风扇规格与数目，在设计上要注意的有这么几点： A、各风扇风场方向要一致，不要互相打架，否则效率肯定大打折扣，对机箱内部来说最好有相应的进风口与出风口，可以参考一下下面的附图，是一块显卡的散热设计； B、采用强制风冷时，对于页片式散热片来说，要使页片方向与风道气流方向一致 c、机箱上要根据风场的需要留出相应的散热孔，散热孔并非越多、越大就越好，首先散热孔的大小根据不同的安规等级