【正文】 ................................................................................................................................................ 11 種薯切塊大小對生物經(jīng)濟性狀的關(guān)系 .......................................................................................... 12 ................................................................................................................ 15 傳動比的計算 ......................................................................................................................................... 15 齒輪傳動設(shè)計 ......................................................................................................................................... 16 齒輪材料的選擇原則 ........................................................................................................................ 16 齒輪的設(shè)計 計算 ................................................................................................................................. 18 ........................................................................................................................ 19 軸的技術(shù)要求 ........................................................................................................................................... 19 軸的主要技術(shù)參數(shù) .............................................................................................................................. 20 軸的材料、毛坯及熱處理 .................................................................................................................... 20 排種立軸的材料及尺寸的確定 ........................................................................................................... 21 .................................................................................................................... 22 總結(jié) ............................................................................................................................................... 22 參考文獻(xiàn) ....................................................................................................................................... 23 致謝 ............................................................................................................................................... 24 張忠喜：轉(zhuǎn)盤式馬鈴薯排種器的設(shè)計 1 課題背景和科學(xué)意義 馬鈴薯是一種世界性的經(jīng)濟作物，其產(chǎn)量僅排在小麥、玉米和水稻之后，占第四位。 在歐美的發(fā)達(dá)國家中，馬鈴薯播種機經(jīng)過幾十年的發(fā)展和應(yīng)用，其技術(shù)水平幾經(jīng)達(dá)到了相當(dāng)完善的程度，無論是工作速度、生產(chǎn)效率、工作性能、播種質(zhì)量以及播種機具的通用性和適用性上都做得比較好。馬鈴薯種植機的基本農(nóng)藝要求是單薯或單塊點種或穴種。新的排種原理包括氣力式排種原理和機械式排種原理也應(yīng)得到廣泛的采用。剩下的單顆粒種薯在重心力矩的作用下逐漸采取以后軸平置的方式穩(wěn)躺在托勺內(nèi)。 地膜覆蓋是各種作物利用最廣的保護(hù)栽培技術(shù)，塑料薄膜在農(nóng)業(yè)上的使用被人們稱為“白色革命”。再者，由于發(fā)苗期不同，如果不能及時的讓秧苗露出，將使秧苗由于膜下溫度過高而灼傷，放苗需要完全仍工作業(yè)，由于出苗期不一致，放苗必須及時，所以需要耗費大量人力。才能提高覆膜質(zhì)量和工作效率。刮種器由刮種舌、彈簧、殼體和調(diào)節(jié)螺釘組成，推種器采用推種輪式推種器，由推種桿、推種彈簧、推種輪和調(diào)節(jié)螺 釘組成。 種箱結(jié)構(gòu)參數(shù)的設(shè)計 種箱尺寸的確定 種箱必須有足夠的容量，從而減少加種次數(shù)，一般情況下，播種到了地頭才加種。其種箱容積 V可用公式 41確定： V=(41) 式中： L—— 裝滿一箱種子所能播種的最遠(yuǎn)距離。 （ 1） 轉(zhuǎn)盤的結(jié)構(gòu) 1）由于馬鈴薯種薯尺寸較一般種子大，在排種盤設(shè)計過程中種盤厚度較厚，這樣會增加排種盤的重量，同時會增加整個機構(gòu)的重量，要減小排種盤重量，一、可以通過減小排種盤直徑；二、在滿足設(shè)計要求的前提下將排種盤制成半空心，從而減輕重量。 目前世界上馬鈴薯約有 2022多個品種。 產(chǎn)量相等，品種不同，薯塊的重量分布也會差異懸殊（表 51） 表 51 薯塊品種與重量之間的差異 馬鈴薯品種 產(chǎn) 量 薯塊重量分布（ g） （ t/hm2） 最大的 中等的 最小的 勞 爾 290 75 20 早玫瑰 110 102 20 (2)種薯的摩擦角 在馬鈴薯種植機工作過程中，種薯箱內(nèi)的薯塊之間、薯塊與排薯器器件之間以及薯箱側(cè)壁之間均將產(chǎn)生摩擦。 種薯切塊大小對生物經(jīng)濟性狀的關(guān)系 （ 1）種薯切塊大小與生育期的關(guān)系 從表 52 可以看出，出苗、現(xiàn)蕾、開花和成熟都隨著 種薯增大而提早，從出苗到成熟的生育期隨種薯增大而縮短 [5]。地下匍匐莖的膨大即形成 薯塊，匍匐莖的個數(shù)在一定程度上直接影響產(chǎn)量。借鑒相關(guān)的馬鈴薯播種機械，將傳動路線分為兩條線。 齒輪表面硬化的方法有：滲碳、氮化和表面淬火。但應(yīng)注意硬度高的齒面粗糙度值也要相應(yīng)的減小 [8]。的齒輪，這樣做可增加齒輪的柔性，降低噪聲和動載荷。 （ 2）模數(shù) 大端模數(shù) m= 11dz = = 取標(biāo)準(zhǔn)模數(shù) m=3mm。它主要起支 撐傳動件和傳遞轉(zhuǎn)矩的作用。軸 的軸頸是軸類零件的重要表面，它的加工質(zhì)量好壞直接影響軸加工時的回轉(zhuǎn)精度。 3）表面粗糙度。 3）軸的熱處理。預(yù)加工包括校正、切斷和切端面和鉆中心孔。排種器在設(shè)計過程中加入了推種刮種器，用以提高排種圓盤的充種性能。t appealed against the disciplinary action your employer has taken against you. However, if you win your case, the tribunal may reduce any pensation awarded to you as a result of your failure to appeal. Remember that in most cases you must make an application to an employment tribunal within three months of the date when the event you are plaining about happened. If your application is received after this time limit, the tribunal will not usually accept i. If you are worried about how the time limits apply to you, take advice from one of the anisations listed under Further help. Employment tribunals are less formal than some other courts, but it is still a legal process and you will need to give evidence under an oath or affirmation. Most people find making a claim to an employment tribunal challenging. If you are thinking about making a claim to an employment tribunal, you should get help straight away from one of the anisations listed under Further help. If you are being represented by a solicitor at the tribunal, they may ask you to sign an agreement where you pay their fee out of your pensation if you win the case. This is known as a damagesbased agreement. In England and Wales, your solicitor can39。s governing body, has also ordered an immediate investigation into the referee39。 Junior high school, thought to have a crush on just means that the real growth, but over the past three years later, his writing of alumni in peace, suddenly found that isn39。想要的，不想要的，界限明確，好像沒有什么可以撼動自己。t start planning... Those years, those days of do, finally, like youth, will end in our life. 此刻，天空是陰暗的，空氣里有著剛下過雨之后的清新因子。 Baumgartner the disappointing news: Mission aborted. r plays an important role in this mission. Starting at the ground, conditions have to be very calm winds less than 2 mph, with no precipitation or humidity and limited cloud cover. The balloon, with capsule attached, will move through the lower level of the atmosphere (the troposphere) where our daytoday weather lives. It will climb higher than the tip of Mount Everest ( miles/ kilometers), drifting even higher than the cruising altitude of mercial airliners ( miles/ kilometers) and int