【正文】 5828840519002600 調(diào)心滾子軸承校核①計算當(dāng)量動載荷P由于調(diào)心滾子軸承承受徑向載荷， 徑向力P=fbRfb——載荷系數(shù)取fb=P==②計算軸承壽命滿足條件2) 低速級行星輪內(nèi)雙列深溝球軸承的校核選用雙列深溝球軸承6205，取Lh＝12000h。其參數(shù)如表53所示：表53軸承型號DmmdmmTmmemmY mm額定動負(fù)載kN額定靜負(fù)載kN極限轉(zhuǎn)速r/min脂潤滑油潤滑62034017121600020000深溝球軸承校核①計算當(dāng)量動載荷P由于軸承承受徑向載荷， 徑向力P=fbRfb——載荷系數(shù)取fb=P==軸承的內(nèi)外圈相對轉(zhuǎn)速n=(1+122/51)②計算軸承壽命滿足條件所以： 該行星回轉(zhuǎn)減速器每一年時間需要檢修，更換其輸出軸上的調(diào)心滾子軸承。6 液壓傳動系統(tǒng)的原理設(shè)計 參考國內(nèi)同斗容的液壓挖掘機(jī)的液壓傳動系統(tǒng)，選擇雙泵雙路分功率調(diào)節(jié)變量系統(tǒng)?！?7176。挖掘機(jī)小負(fù)荷時，泵輸出的流量大，動作速度快；大負(fù)荷時，泵輸出流量小，工作裝置可以較低的速度克服較大的負(fù)荷。每臺泵只能輸出發(fā)動機(jī)功率的的二分之一，且各自獨(dú)立調(diào)節(jié)。 背壓閥壓力調(diào)到1MPa，系統(tǒng)中各執(zhí)行元件均設(shè)有各自的過載閥，以起安全保護(hù)作用。行走馬達(dá)油路中裝有速度限制閥7，防止液壓挖掘機(jī)溜坡圖61 液壓傳動系統(tǒng)原理圖總 結(jié)在本次設(shè)計中，在國內(nèi)同斗容產(chǎn)品的測繪的基礎(chǔ)上，利用經(jīng)驗(yàn)統(tǒng)計公式、旋轉(zhuǎn)矢量法及力學(xué)計算，以機(jī)重為50t的挖掘機(jī)工作裝置為對象，進(jìn)行了以下設(shè)計工作：結(jié)合經(jīng)驗(yàn)公式進(jìn)行了挖掘機(jī)工作裝置的總體設(shè)計，并用旋轉(zhuǎn)適量法對工作裝置進(jìn)行了運(yùn)動學(xué)分析。以動臂、斗桿建立起坐標(biāo)系，利用成熟的經(jīng)驗(yàn)公式，選擇出鏟斗，動臂，斗桿基本參數(shù)。 參考同斗容挖掘機(jī)產(chǎn)品的轉(zhuǎn)臺最大旋轉(zhuǎn)扭矩，進(jìn)行了回轉(zhuǎn)機(jī)構(gòu)的設(shè)計，包括回轉(zhuǎn)支撐的選擇，回轉(zhuǎn)驅(qū)動油泵的選擇，行星減速器的設(shè)計計算等工作。我知道這些都是一些皮毛，但在指導(dǎo)老師的指導(dǎo)下，同學(xué)的幫助下使我對以后的學(xué)習(xí)，工作加強(qiáng)了信心。Hydraulic shovel。State feedback。and g s gravitational acceleration. u is the joint angle,t is the supply torque the attachment length,1 g iis the distance between the fulcrum and the center of gravity,m iis the mass of the attachment,I iis the moment of inertia around the center of gravity ?subscripts i s 1–3,mean boom, arm,and bucket,respectively.. model Each joint is driven by a hydraulic cylinder whose flow is controlled by a spool valve,as shown in Fig. can assume the following: open area of a valve is proportional to the spool displacement. is no oil leak. pressure drop occurs when oil flows through, Automation in Construction 10 (2001) 477–486 479 of hydraulic shovel. effective sectional area of the cylinder is the same on both the head and the rod sides. In this problem,for each joint,we have the following equation from the pressure flow characterstics of the cylinder:時；where,A is effective crosssectional area of cylinder。X is spool displacement。P1 is cylinder headside pressure。Vi s oil volume in the cylinder and piping。 gsoil density。and cs flow coefficient. relationsIn the model shown in ,the relation between the cylinder length change rate and the attachment rotational angular velocity is given asfollows:?1. boom relations From the link relations of Section ,the supplytorque t is given as follows,taking cylinder friction I into consideration:Where,C ciis the viscous friction coefficient and Fi is kinetic frictional force of a cylinder characteristics of the spool Spool action has a great effect on control ,we are assuming that the spool hasthe following firstorder lag against the reference input. iis the reference input of spool dis placement and Ts piis a time constant. control systemAs shown in ,the angle u is basically controlled to follow the reference angle ug by position order to obtain more accuratecontrol,nonlinear pensation and state feedback are added to the position will discuss details of these algorithms as follows. pensationIn the ordinary automatic control systems,new control devices such as servo valves are our semiautomatic system,in order to realize the coexistence of manual and automatic operations,we must use the main control valves,which are used in manual these valves,the relation between spool displacement and open area is nonlinear. Then,in automatic operation,using this relation,the spool displacement is inversely calculated from the required open area,and the nonlinearity is pensated ?.. diagram of control system ?u.., Automation in Construction 10 (2001) 477–486 481 pensation. feedbackBased on the model discussed in Section 2,if thedynamic characteristics for boom angle control are linearized in the vicinity of a certain standard condition ?spool displacement X10,cylinder differential pressure P,and boom angle u.,the closedlooptransfer function can be expressed by This system has a paratively small coefficient a1so the response is instance,if in our large SK16 hydraulic shovel,X 10is 0,thecoefficients are given as a s =10 accelerationfeedback of gain Ka,to this ?the upper loop in Fig.4.,the closed loop transfer function is given as Adding this factor,the coefficient of s2 bees larger,thus,the system bees this way,acceleration feedback is effective in improving the response characteristics.However,it is generally difficult to detect acceleration overe this difficulty,cylinder force feedback was applied instead of acceleration feedback ?the lower loop in ..In this case,cylinder force is calculated from detected cylinder pressure and filtered in its lowerfrequency portion w 7, is called pressure feedback. control systemWhen one joint is manually operated and another joint is controlled automatically to follow the manual operation,a servo control system must be required. For example,as shown in ,in the level crowding control,the boom is controlled to keep the arm end height Z ?calculated from u and u .to reference order to obtain more accurate control,thefollowing control actions are , Automation in Construction 10 (2001) 477–486 diagram of control system ?Z.. control Calculating Z from ,we obtain Differentiating both sides of Eq.?8. with respect to time,we have the following relation,The first term of the righthand side can be taken as the expression ?feedback portion. to convert Z˙ to u˙,and the second term of the righthand side is the expression ?feedforward portion. to calculate how much u should be changed when u is changed 1 2 manually.Actually,u˙ is determined using the difference 2 value of optimize he feedforward rate,feedforward gain K ffis tunned. There may be a method to detect and use the arm operatinglever condition ?. instead of arm angular velocity,since the arm is driven at an angular velocity nearly proportional to this