【正文】 得到了很多鍛煉,特別是在綜合策劃設(shè)計流程上有了很大的提高,也加深以前學(xué)過的基礎(chǔ)理論知識和專業(yè)理論知識,由于經(jīng)驗不足水平有限,難免會出現(xiàn)錯誤,希望能及時提供寶貴的意見和建議。s service braking system. The failure of a part of a hydraulic transmission system shall be signalled to the driver by a device prising a red warning signal,as specified in paragraph . Alternatively, the lighting up of this device when the fluid in the reservoir is below a certain level specified by the manufacturer shall be permitted.. Where use is made of energy other than the muscular energy of the driver,there need not be more than one source of such energy(hydraulic pump, air pressor, etc.), but the means by which the device constituting that source is driven must be as safe as practicable.. In the event of failure in any part of the transmission of a braking system, the feed to the part not affected by the failure must continue to be ensured if required for the purpose of halting the vehicle with the degree of effectiveness prescribed for residual and/or secondary condition must be met by means of devices which can be easily actuated when the vehicle is stationary,or by automatic means.. Furthermore, storage devices located downcircuit of this device must be such that in the case of a failure in the energy supply after four fullstroke actuations of the service brake control,under the conditions prescribed in paragraph . of annex 7 to this Regulation,it is still possible to halt the vehicle at the fifth application,with the degree of effectiveness prescribed for secondary braking.. However,for hydraulic braking systems with stored energy, these provisions can be considered to be met provided that the requirements of paragraph Part C of annex 7 to this Regulation, are satisfied.. The requirements of paragraphs ., . and this Regulation must be met without the use of any automatic device of a kind such that its ineffectiveness might pass unnoticed through the fact that parts normally in a position of rest e into action only in the event of failure in the braking system.. The service braking system shall act on all wheels of the vehicle and shall distribute its action appropriately among the axles.. In the case of vehicles with more than two axles,in order to avoid wheellocking or glazing of the brake linings, the brake force on certain axles may be reduced to zeroautomatically when carrying a much reduced load, provided that the vehicle meets all the performance requirements prescribed in annex 4 to this Regulation.. . Intrinsic variations in the braking system ( a result of changes in the electric state of charge in the traction batteries)are automatically pensated by appropriate variation in the phasing relationship as long as the requirements / of one of the following annexes to this Regulation are satisfied: In the case of M1 and N1 category vehicles with electric regenerative braking systems of category B,the braking input from other sources of braking, may be suitably phased to allow the electric regenerative braking system alone to beapplied, provided that both the following conditions are met: Annex 4,paragraph .,or Annex 13, paragraph . (including the case with the electric motor engaged). Wherever necessary, to ensure that braking rate 5/ remains related to the driver’s braking demand, having regard to the available tyre/road adhesion, braking shall automatically be caused to act on all wheels of the vehicle. The action of the service braking system shall be distributed between the wheel sof one and the same axle symmetrically in relation to the longitudinal median plane of the and functions, such as antilock, which may cause devia tions from this symmetrical distribution, shall be declared.. Compensation by the electric control transmission for deterioration or defect within the braking system shall be indicated to the driver by means of the yellow warning signal specified in paragraph . This requirement shall apply for all conditions of loading when pensation exceeds the following limits: . a difference in transverse braking pressures on any axle: (a)of 25 per cent of the higher value for vehicle decelerations $ 2m/sec2,(b)a value corresponding to 25 per cent at 2m/sec2 for decelerations below this rate.. an individual pensating value on any axle:(a)50 per cent of the nominal value for vehicle decelerations $ 2 m/s2,(b)a value corresponding to 50 per cent of the nominal value at 2m/s2 for decelerations below this rate.( （c）The Authority, which is to grant approval,shall have the right to check the service braking system by additional vehicle test procedures.. Compensation as defined above, is permitted only when the initial brake application is made at vehicle speeds greater than 10 km/h.. Malfunctions of the electric control transmission shall not apply the brakes contrary to the driver39。參考文獻(xiàn)[1] 陳家瑞,[M].人民交通出版社,. [2] 王季坤,[M]..[3] 艾興,[M]，機(jī)械工業(yè)出版社,.[4] [M].北京：機(jī)械工業(yè)出版社.[5] 機(jī)械制造工藝設(shè)計手冊簡明手冊[M]。(2)標(biāo)準(zhǔn)化。CAFD系統(tǒng)已經(jīng)從對二維繪圖軟件的二次開發(fā)發(fā)展到實現(xiàn)與三維繪圖軟件的集成設(shè)計，使夾具的結(jié)構(gòu)表達(dá)更清晰。根據(jù)國內(nèi)外現(xiàn)已開發(fā)的夾具設(shè)計軟件系統(tǒng)，計算機(jī)輔助夾具設(shè)計是目前比較成熟的夾具設(shè)計系統(tǒng)。然后進(jìn)入三維繪圖環(huán)境，采用人工交互的方式進(jìn)行參數(shù)化驅(qū)動，以獲得尺寸滿足要求的零件和部件，裝配后繪出裝配圖和零件圖。傳統(tǒng)夾具設(shè)計理論與先進(jìn)的計算機(jī)技術(shù)相結(jié)合而開發(fā)出的各種CAFD系統(tǒng)成為專用夾具新的設(shè)計方法。，如何避免加工件發(fā)生不能允許的振動，是正確夾緊原則之四。因此，當(dāng)加工件正確定位后．還需要獲得良好的夾緊狀態(tài)。1 定位原理把加工件上的規(guī)定表面(線、點(diǎn))與夾具上的規(guī)定表面(線、點(diǎn))相互靠住的這一措施，叫做夾工件在夾具中的定位。利用夾具，可以提高勞動生產(chǎn)率，提高加工精度，減少廢品；可以擴(kuò)大機(jī)床的工藝范圍，改善操作的勞動條件。并按要求標(biāo)注夾具有關(guān)的尺寸、公差和技術(shù)要求[1214]。查《機(jī)床夾具設(shè)計手冊》表127得：，表128得，鉆頭的直徑為d=，所以。 確定定位方案，設(shè)計定位元件工件上的加工孔為通孔，沿孔軸線方向的自由度可不予以限制，但是為增強(qiáng)加工時工件的剛性，必定限制孔軸線方向的自由度，故應(yīng)按完全定位設(shè)計夾具，并力求遵守基準(zhǔn)重合原則，以減少定位誤差對加工精度的影響。查《機(jī)床夾具設(shè)計手冊》表127得：，表128得，其中，查《機(jī)床夾具設(shè)計手冊》表121得：；；；；，所以=。 車削頂尖夾具的設(shè)計 問題的提出夾具的種類很多，有通用夾具，專用夾具和組合夾具等，本夾具是用來車削粗車和半精車半軸的外圓和臺階面的，由于本零件比較特殊，為了使定位誤差為零 ，我們設(shè)計基準(zhǔn)為半軸左右兩邊的的頂尖位置，作為主要的基準(zhǔn)。⑤ 計算基本工時t=，式中，L=l+y+△，l=14，查《切削用量簡明手冊》，y+△=7，所以，L= 10+5 = 15。2 選擇切削用量① 進(jìn)給量f根據(jù)《切削用量簡明手冊》，取f=～, 查閱《機(jī)械制造工藝設(shè)計簡明手冊》—16，所以，取 f= 根據(jù)《切削用量簡明手冊》 ,可以查出鉆孔時的軸向力，當(dāng)f ≤，d≤12mm時，軸向力F