【正文】 （1）體積小、 重量輕、安裝方便、無傳動(dòng)部件、不需潤滑、維修方便、運(yùn)行費(fèi)用低。但是該振機(jī)振幅因受電源影響不夠穩(wěn)定，而且造價(jià)高，在篩機(jī)中應(yīng)用較小。慣性式振動(dòng)機(jī)按照動(dòng)力學(xué)的特性，可分為線性非共振式、線性近共振式、非線性式和沖擊式振動(dòng)等。慣性式激振器通常由主軸、偏心塊、軸承、軸承座組成其按照激振器軸數(shù)又可以分為單軸式、雙軸式、多軸式三種。因此，我們選用了自同步電機(jī)驅(qū)動(dòng)的雙軸慣性式振動(dòng)篩。隔振系統(tǒng)有一次隔振和二次隔振及多次隔振系統(tǒng)等下面通過分析我們進(jìn)行選用。由于本次設(shè)計(jì)的直線振動(dòng)細(xì)篩一般安裝與地面，因此采用一次隔振裝置。承重管梁與側(cè)板之間使用精制高強(qiáng)度螺栓緊固，這種緊固方式不僅使被緊固件之間利用靜摩擦傳遞振動(dòng)力，而且利用高強(qiáng)度螺桿與鋼板孔的過盈配合，直接傳遞振動(dòng)剪切力，聯(lián)接強(qiáng)度高，使用防松螺母，聯(lián)接可靠不松動(dòng)，將篩箱聯(lián)接成一個(gè)剛性箱體結(jié)構(gòu)，是目前最為有效的聯(lián)接方式。（1）棒條篩①棒條篩由一組具有一定斷面的棒條組成，這種篩面通常用于固定篩或重型振動(dòng)篩中，篩孔尺寸在50mm以上。新型縫條篩常用焊條。 篩面的壓緊裝置篩面在箱體上的安裝固定方法有三種：用拉鉤拉緊、用木楔條壓緊、用壓板和螺釘固定。綜上所述，本設(shè)計(jì)采用木楔條固定壓緊裝置。支撐裝置主要是彈性材料，常用的有金屬螺旋彈簧、板彈簧和橡膠彈簧。其缺點(diǎn)是體積較大、容易產(chǎn)生噪音、調(diào)節(jié)其剛度不便、橫向剛度小容易使機(jī)體出現(xiàn)橫向搖晃。其特點(diǎn)是結(jié)構(gòu)緊湊、可調(diào)節(jié)硬度或結(jié)構(gòu)來改變其剛度、振幅穩(wěn)定、能耗大、隔音效果好、噪音小。采用物料作拋擲運(yùn)動(dòng)狀態(tài)進(jìn)行設(shè)計(jì)，此種運(yùn)動(dòng)形式有如下優(yōu)點(diǎn)：可防止篩孔的堵塞，并能獲得較好的篩分效率和生產(chǎn)率；而且由于物料和工作面接觸時(shí)間短大部分離開工作面，所以工作面的磨損小，并能獲得較高的輸送速度，而且運(yùn)用此種運(yùn)動(dòng)形式可使上下層物料得到翻動(dòng)，使細(xì)粒物的透篩機(jī)會(huì)增多，從而提高工作效率。 振動(dòng)方向角的選擇 振動(dòng)方向角α是指振動(dòng)方向線與工作面的夾角，它的選擇主要根據(jù)機(jī)器的用途做篩分使用時(shí)，應(yīng)保證有較高的篩分效率和較大的產(chǎn)量。②際平均速度： V=CmCRCa CωVd (52)Cm—物料性質(zhì)的影響系數(shù)，；CR—料層厚度的影響系數(shù)，；Ca—傾角的影響系數(shù)，；Cω—滑行運(yùn)動(dòng)影響系數(shù)，取1；因此實(shí)際平均速度為：V=。 隔振系統(tǒng)的頻率比及隔振彈簧剛度隔振系統(tǒng)的頻率比范圍2～10根據(jù)工作頻率取Z0=5。只有這樣中國的篩分技術(shù)才能跟住世界潮流，才能為中國工業(yè)的未來再多做些貢獻(xiàn)，它的發(fā)展不僅僅代表著中國礦山機(jī)械的發(fā)展，它還代表著中國國力的增強(qiáng)，標(biāo)志著一個(gè)國家的基礎(chǔ)工業(yè)的實(shí)力和工業(yè)科技水平。從課題的確立，圖紙的設(shè)計(jì)到最后論文的批改，無不凝聚著導(dǎo)師的心血。Link mechanismLinkages include garage door mechanisms, car wiper mechanisms, gear shift mechanisms.In every machine, at least one link either occupies a fixed position relative to the earth or carries the machine as a whole along with it during motion. These type of connections, revolute and prismatic, are called lower pairs. Higher pairs are based on point line or curve interfaces. Examples of lower pairs include hinges rotary bearings, slideways , universal couplings. Examples of higher pairs include cams and gears.Kinematic analysis, a particular given mechanism is investigated based on the mechanism geometry plus factors which identify the motion such as input angular velocity, angular acceleration, etc. Here, both choosing the types as well as the dimensions of the new mechanism can be part of kinematic synthesis.Planar, Spatial and Spherical MechanismsA planar mechanism is one in which all particles describe plane curves is space and all of the planes are coplanar.. Spatial mechanisma are far more plicated to engineer requiring puter synthesis. The motions of all of the particles in the mechanism are concentric and can be repesented by their shadow on a spherical surface which is centered on the mon location..Spherical mechanisms /linkages are not considered on this pageMobilityAn important factor is considering a linkage is the mobility expressed as the number of degrees of freedom.It is possible to determine this from the number of links and the number and types of joints which connect the links...A free planar link generally has 3 degrees of freedom (x , y, θ ). s law provides a simple test for this conditionGrashof39。 It can be proved that the mechanical advantage is directly proportional to Sin( β ) the angle between the coupler link(c) and the driven link(d), and is inversely proportional to sin( α ) the angle between the driver link (b) and the coupler (c) .These positions are referred to as toggle positions. As the value sin(transmission angle) bees small the mechanical advantage of the linkage approaches zero. When using four bar linkages to transfer torque it is generally considered prudent to avoid transmission angles below 450 and 500.In the figure above if link (d) is made the driver the system shown is in a locked position. If three position of the output lever are required corresponding to the angular position of the input lever at three positions then this equation can be used to determine the appropriate lever lengths using three simultaneous equations... Velocity Vectors for LinksThe velocity of one point on a link must be perpendicular to the axis of the link, otherwise there would be a change in length of the link.On the link shown below B has a velocity of vAB = perpendicular to AB. The velocity of C relative to B is perpedicular to CB and passes through b relative to A = perpendicular to the line. The velocity of B relative to B39。 The diagram below shows how to to construct a vector diagram for the acceleration ponents on a s。 1) the centripetal ponent due to the angular velocity of the The velocity of P is obtained from the vector diagram by using the relationship bp/bc = BP/BC The velocity vector diagram is easily drawn as shown... Velocity of sliding Block on Rotating LinkConsider a block B sliding on a link rotating about A. The block is instantaneously located at B39。 As A and D are fixed then the velocity of D relative to A = 0 a and d are located at the same point K3 = ( l 32 l 12 l 22 l 2 4 ) / 2 l 2 l 4 This equation enables the analytic synthesis of a 4 bar linkage. K2 = l 1 / l 2s Equation results from this relationship as K 1 cos θ 2 + K2 cos θ 4 + K 3 = cos ( θ 2 θ 4 )K1 = l1 / l4 The system has no toggle positions and the linkage is a poor design Freudenstein39。 In these region the linkage is very liable to lock up with very small amounts of friction.These positions allow the 4 bar linkage to be used a clamping tools.The angle β is called the transmission angle.These angles are not constant so it is clear that the mechanical advantage is constantly changing.The linkage positions shown below with an angle α = 0 o and 180 o has a near infinite mechanical advantage.s law states that one of the links (generally the shortest link) will be able to rotate continuously if the following condition is met... b (shortest link ) + c(longest link) a + dFour Inversions of a typical Four Bar LinkageNote: If the above condition was not met then only rocking motion would be possible for any link..Mechanical Advantage of 4 bar linkageThe mechanical advantage of a linkage is the ratio of the output torque exerted by the driven link to the required input torque