機械類相關英語文章精選
在發展傳統機械工程技術的同時,在機械工程技術中還必須融入環境技術,走可持續發展的戰略。下面是本站小編帶來的機械類相關英語文章，歡迎閱讀!
Dimension and Tolerance
尺寸和公差
In dimensioning a drawing, the numbers placed in the dimension lines represent dimensionthat are only approximate and do not represent any degree of accuracy unless so stated bythe designer.
在圖紙標註尺寸時,除非設計者有意標明,注在尺寸線上的數字代表的尺寸僅僅是近似的,並不代表任何精度等級。
To specify a degree of accuracy, it is necessary to add tolerance figures to the rance is the amount of variation permitted in the part or the totAl variation allowed in agiven dimension.
爲了詳細標明精度等級,有必要在尺寸上增加公差數字。公差是零件允許的變動量或給定尺寸允許的總變動。
A shaft might have a nominal size of 2.5in.(63.5mm), but for practical reasons this figurecould not be maintained in manufacturing without great cost. Hence, a certain tolerance wouldbe added and, if a variation of±0.003in.(±0.08mm) could be permitted, the dimension wouldbe stated 2.500±0.003(63.5±0.08mm).
一根軸可能的名義尺寸爲2.5in.(63.5mm),但由於實際原因不用大成本是不能在製造中保持這個數字的,因此要增加確定的公差。如果允許有±0.003in.(±0.08mm)的變化,則此尺寸可表達爲2.500±0.003(63.5±0.08mm)。
Dimensions given close tolerances mean that the part must fit properly with some other must be given tolerances in keeping with the allowance desired, the manufacturingprocesses available, and the minimum cost of production and assembly that will maximizeprofit.
具有緊密公差的尺寸表示該零件必須恰當地與某些其它零件配合。所採用的製造工藝和使利潤最大化的最小生產及裝配成本都要求給定公差以保持所需允差。
Generally speaking, the cost of a part goes up as the tolerance is decreased. If a part hasseveral or more surfaces to be machined, the cost can be excessive when little deviation isallowed from the nominal size.
一般而言,零件的成本隨着公差的減小而上升。如果一個零件有若干或較多表面要機加工且幾乎不允許偏離名義尺寸,則成本會超過正常合理的界限。
機械類相關英語文章閱讀允差
Allowance, which is sometimes confused with tolerance, has an altogether different is the minimum clearance space intended between mating parts and represents the conditionof tightest permissible fit.
允差.有時會跟公差混淆,但其具有完全不同的含義。它是配合零件之間最小的預期間隙空間,代表着允許的最緊配合條件。
If a shaft, size 1.498-0.003, is to fit a hole of size 1.500+0.003, the minimum size hole is1.500 and the maximum size shaft is 1.498. Thus the allowance is 0.002 and the maximumclearance is 0.008 as based on the minimum shaft size and maximum hole dimension.
如果一根尺寸爲1.498-0.003的軸與尺寸爲1.500+0.003的孔配合,孔的最小尺寸爲1.500而軸的最大尺寸爲1.498。這樣允差就是0.002,而由最小軸尺寸和最大孔尺寸形成的最大間隙爲0.008。
Tolerances may be either unilateral or bilateral. Unilateral tolerance means that any variation ismade in only one direction from the nominal or basic dimension. Referring to the previousexample, the hole is dimensioned 1.500+0.003, which represents a unilateral tolerance.
公差可以是單向的也可以是雙向的。單向公差意味着任何變動都是隻從名義或基本尺寸出發向一個方向變動的。引用前例,孔的尺寸標註爲1.500+0.003,它表示了一個單向公差。
If the dimensions were given as 1.500±0.003, the tolerance would be bilateral; that is, it wouldvary both over and under the nominal dimension. The unilateral system permits changing thetolerance while still retaining the same allowance or type of fit.
如果尺寸標爲1.500±0.003,就是雙向公差即它可以在名義尺寸之上或之下變化。單向體系允許在依然保留相同允差或配合類型的情況下改變公差。
With the bilateral system, this is not possible without also changing the nominal sizedimension of one or both of the two mating parts. In mass production, where mating partsmust be interchangeable, unilateral tolerances are customary. To have an interference orforce fit between mating parts, the tolerances must be such as to create a zero or negativeallowance.
而雙向體系在不同時改變一個或兩個配合零件名義尺寸的情況下,這是不可能做到的。大規模生產中配合零件必須能互換,單向公差是經常遇到的。爲了使配合零件之間具有過盈或強制配合,公差必須產生零或負允差。
機械類相關英語文章學習Tolerances, Limits and Fits
公差、極限和配合
The drawing must be a true and complete statement of the designer's requirementsexpressed in such a way that the part is convenient to manufacture.
圖紙必須按方便製造零件的方式將設計者的要求真實和完整地表達出來。
Every dimension necessary to define the product must be stated once only and not repeatedin different views. Dimensions relating to one particular feature, such as the position and sizeof a hole, should, where possible, appear on the same view.
對每一描述產品所需的尺寸都只須標註一次而不必在不同的視圖中重複。有關同一特性的尺寸 諸如孔的位置和大小 如果可能應出現在同一視圖上
There should be no more dimensions than are absolutely necessary, and no feature should belocated by more than one dimension in any direction.
除絕對需要的尺寸外 不應該有更多的尺寸而在任意方向上 只能在一個尺寸上標註特性要求。
It may be necessary occasionally to give an auxiliary dimension for reference, possibly forinspection. When this is so, the dimension should be enclosed in a bracket and marked forreference. Such dimensions are not governed by general tolerances.
偶爾也可能爲了檢查而必須給出供參考的輔助尺寸。在這種情況下 尺寸應該用括號括起來以便參考。這樣的尺寸不受通用公差控制。
Dimensions that affect the function of the part should always be specified and not left as thesum or difference of other dimensions.
影響零件功能的尺寸總是應該標註的而不要留作其它尺寸的和或差。
If this is not done, the total permissible variation on that dimension will form the sum ordifference of the other dimensions and their tolerances, and this will result in these toleranceshaving to be made unnecessarily tight. The overall dimension should always appear.
如果不是這樣 那尺寸允許的總的變化將形成其它尺寸及它們的公差的和或差 這會導致這些公差不得不定得過緊。總尺寸一般應該標註。
All dimensions must be governed by the general tolerance on the drawing unless otherwisestated. Usually, such a tolerance will be governed by the magnitude of the ific tolerances must always be stated on dimensions affecting function orinterchangeability.
除非另行說明 所有尺寸都必須受圖上的通用公差控制。一般這樣的公差受到尺寸量值的控制。在影響功能或互換性的尺寸上必須標註專門的公差。
