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附錄1 譯 文
摘 要:錘片磨損會破壞錘片式粉碎機轉(zhuǎn)子的平衡,加劇轉(zhuǎn)子振動。該文的研究目的是基于虛擬樣機技術(shù)探討錘片磨損對轉(zhuǎn)子振動的影響規(guī)律。采用MDT和vN4D建立了SFSP112×30型錘片式粉碎機轉(zhuǎn)子的虛擬樣機模型,對不同錘片磨損情況下粉碎機轉(zhuǎn)子的振動進行了仿真。結(jié)果表明:錘片磨損后,轉(zhuǎn)子振動頻率組成變化不大,而振動幅值和強度變化較大,其中低頻段振動強度增強,高頻段振動強度降低;導(dǎo)致轉(zhuǎn)子質(zhì)心徑向偏移的錘片磨損使轉(zhuǎn)子振動幅值和強度均變大,而導(dǎo)致質(zhì)心軸向偏移的磨損對轉(zhuǎn)子振動影響不大;同樣由于轉(zhuǎn)子質(zhì)心的徑向偏移,轉(zhuǎn)子受迫振動頻率強度增加較多。因此,為了降低子運轉(zhuǎn)時的振動,最好避免轉(zhuǎn)子質(zhì)心發(fā)生徑向偏移。
關(guān)鍵詞:錘片式粉碎機;錘片;虛擬樣機(VP);磨損;振動
簡 介
能從谷物中的營養(yǎng)提取出來的飼料粉碎機已經(jīng)發(fā)展很多年了。但是因為他只能處理特殊的原料,像谷類食品和礦石,所以除了丕林島(地名)的少數(shù)人在研究飼料粉碎機外,很少人去研究他。盡管飼料粉碎機已經(jīng)可以解決很多問題,比如振動、噪音、堵塞,用他特有的結(jié)構(gòu)來解決問題,而且可以連續(xù)工作并達到一定的精度。
雖然一些方法,比如比較低的回轉(zhuǎn)速度,寬的轉(zhuǎn)子直徑被采用,好轉(zhuǎn)了他的性能,但是那些問題不能扯得的被解決。最近,分析了飼料粉碎機在工作狀態(tài)下轉(zhuǎn)子的轉(zhuǎn)速,旋轉(zhuǎn)的速度能被粉碎機控制在稍低或者稍高的程度。轉(zhuǎn)子的轉(zhuǎn)速在正常工作下都是不變的,除了在長時間工作摩擦后。由于錘片的排列或者是其他的因素,產(chǎn)生轉(zhuǎn)子的離心力不固定,所以錘片的磨損是不均衡的,因此,我們要學(xué)習(xí)掌握錘片要磨損時候的特征,為了使粉碎機振動保持穩(wěn)定。
實質(zhì)上的原型技術(shù)(VP)是一個用cad加工程序代替真實的模型,為了測試這種產(chǎn)品的特性和特征。這就像電腦的硬件和軟件的發(fā)展,網(wǎng)絡(luò)技術(shù)通過vp技術(shù)開展起來。同時,傳統(tǒng)的模擬技術(shù)對VP的認識理解很有基礎(chǔ)。除了高科技種田,VP技術(shù)還適用于日益發(fā)展的農(nóng)業(yè)機械設(shè)計。作者努力的將VP技術(shù)應(yīng)用于工程分析技術(shù)。
對于飼料粉碎機中轉(zhuǎn)子單一的動力模型,被用來發(fā)展轉(zhuǎn)子動力學(xué),轉(zhuǎn)子有效的運動模型被MDT和VN4D當(dāng)做虛擬原型來用。VP技術(shù)模擬不同情況的磨損下,研究轉(zhuǎn)子轉(zhuǎn)動時的震動和錘片磨損的分析。
1.單一化轉(zhuǎn)子的模型
SFSP112×30的轉(zhuǎn)子的錘片被均勻的排列,它是由定子、滾球軸承、錘片、軸子組成,最大轉(zhuǎn)速為1480r/min。所以它的最大頻率應(yīng)該是1480/60=24.6Hz。
圖一 SFSP112×30的轉(zhuǎn)子圖表
基于集總的單一化原則叁數(shù)方法 被單一化的模型應(yīng)該有同樣的總質(zhì)量,瞬間的轉(zhuǎn)動慣量有最初的質(zhì)心位置決定。粉碎機的轉(zhuǎn)子被單一化的分別運行在六個圓盤里。在這系統(tǒng)里,每一個自我排列的定子,會在壓力的作用下自己運行到指定的位置,能夠計算出他們最后的位置。
2.轉(zhuǎn)子的虛擬原型
轉(zhuǎn)子的3D模型需要建立在一個MDT的三維建模軟件上,VP的技術(shù)原本是用來實現(xiàn)Vn4D的,其中包括重要的參數(shù)從轉(zhuǎn)子的發(fā)動機的功率。一些重要參數(shù)列出如下
(1)定子連接上,平鍵連接被強固連接完全代替;
(2)強固連接也被用來連接圓盤;
(3)因為軸子被用來限制錘片的位置,所以強固連接被用來限制軸子和錘片的位置;
(4)在錘片和螺釘通過強固連接,來限制彼此的旋轉(zhuǎn)動作,來完成軸的夾緊;
(5)球軸承被軸襯所代替,軸襯確定參數(shù)。
(6)電動機的限制被增加到左邊的結(jié)束,他的參數(shù)、轉(zhuǎn)力矩輸出功能被設(shè)置在平衡的感電電動機上
3.VP技術(shù)的模擬分析
為了要加速模擬速度,唯一的沒有外部的那些環(huán)境應(yīng)用的負荷被模擬,同時,粉碎機需要非常短的加速時間,沒有負載的環(huán)境是不可能的。粉碎機需要加速的這段時間內(nèi),轉(zhuǎn)子跑到他的位置上。 錘片的排列的結(jié)果,在研磨中起作用的軸通常用不同種型號,錘片通過定子的排列的長短來確定。因此質(zhì)心上的轉(zhuǎn)子偏離最初的位置。根據(jù)概率公差,質(zhì)心的方向也就是軸運動的方向,磨損的方向是在情理之中的。此外,和磨損情形對比,錘片的磨損也是模擬的。
根據(jù)模擬的結(jié)果列出表1
磨損的圖被展現(xiàn)在圖4上,第四個錘片和軸子被標(biāo)在Ⅰ和Ⅳ上,當(dāng)從軸向觀察,每組的錘片,每組都標(biāo)著1到8平行的定子,在圖4A磨損程度每個錘片是平等的。圖 4B條的磨損程度,每個錘片的一組是不平等的,而相應(yīng)的錘片組有Ⅰ ,Ⅲ 同樣的磨損程度。至于Fig.4c和Fig.4d的磨損程度的錘片是不相同完全。圖5顯示振動加速度和動力頻譜圖的球軸承收集在這一過程中,該轉(zhuǎn)子轉(zhuǎn)過第一第二輪之后, 14號實線代表的振動響應(yīng)左軸承和虛線代表是正確的。 圖4示意圖磨損形式。錘片的磨損的主體部分的振動頻率之前和之后沒有變化。 但強度在每一個頻率是完全不同的圖5振動響應(yīng)每個軸承從相應(yīng)的頻率,損壞轉(zhuǎn)子。在低頻階段加強和強度削弱了在高頻率的階段。特別是根據(jù)“甚至磨損”形勢的變化很大大于其他情況下。和同樣的結(jié)論可以發(fā)現(xiàn)振動擴增管轉(zhuǎn)子。通過對比Fig.5b和Fig.5c , 可以推斷,徑向偏移嚴重破壞了平衡的轉(zhuǎn)子。這一結(jié)論也可以通過Fig.5d和 Fig.5e的對比得到。由于徑向偏移量“相鄰不均勻磨損“顯然是大于“不對稱不均勻磨損” 。強度在強迫振動頻率(24.67赫茲)增加多少更根據(jù)“甚至耐磨”和“相鄰不均勻磨損”的情況,雖然有點變化根據(jù)以上兩種情況對比。
4結(jié)論
?(1)磨損形式并不影響能使錘片的振動頻率改變的轉(zhuǎn)子。然而,它確實帶來了明顯的變化強度的頻率,其中的強度低頻率的階段,同時加強這一高頻率階段的削弱。
(2)徑向偏移現(xiàn)實出來是不穩(wěn)定的轉(zhuǎn)子相對于軸向偏移。振幅和強度大大增加時質(zhì)心偏離徑向。
(3)強度的強迫振動頻率大大提高時,會出現(xiàn)無論是錘片磨損均勻或鄰近群體錘片磨損不均等方面的磨損情況。它需要較大的徑向力來抵消這兩個磨損形式,結(jié)果是不穩(wěn)定的轉(zhuǎn)子。
(4)基于以上這些結(jié)論,為了控制飼料粉碎機的轉(zhuǎn)子的振動,飼料粉碎機的轉(zhuǎn)子不應(yīng)徑向偏移。因此,轉(zhuǎn)子需要很好的平衡特別是需要在達到動態(tài)平衡之前進入正常的運行。
附錄2 英文參考資料
Vibration generated by the abrasion of the hammer slicein feed-grinder based on virtual prototype technology
Abstract: The abrasion of the hammer slice can cause the rotor of the feed-grinder to lose balance and then make the grinder vibrate. A virtual prototype (VP) based on the rotor of SFSP112×30 feed-grinder was set up by using MDT and vN4D for investigating the relationship between the abrasion of the hammer slice and the vibration of the rotor. By simulating the VP with various abrasion forms, it has been found that the abrasion form does not influence the makeup of the vibration frequency but the intensity. That is, the intensity of the low-frequency stage strengthens but that of the high-frequency stage weakens when the hammer slices are worn out. The vibration amplitude and intensity both increase when the abrasion makes the centroid of the rotor offset radially. However, they do not change much when the centroid offsets axially. The intensity of the forced vibration frequency also greatly rises when the center of mass offsets radially.
Therefore, to damp the vibration of the feed-grinder the centroid of the rotor had better not offset radially.
Key words feed-grinder; hammer slice; virtual prototype (VP); abrasion; vibration
Vibration generated by the abrasion of the hammer slice in feed-grinder based on virtual prototype technology[J]. As one of the kernel equipment in feedstuff processing industry, the feed-grinder has been developed for years. But because of its special processing object, like cereal and mineral, there are few theoreti- cal studies on the feed-grinder except some experimen- tal researches. However, while the feed-grinder runs into many problems such as vibration, noise and clog- ging which mainly result from its own structure char- acteristics, running environment and fitting precision.
Although some methods such as lower rotational speed and wider rotor diameter have been adopted to im-prove its performance, those problems cannot be thor- oughly solved. Recently, et al has analyzed the vibration of the feed-grinder by calculat- ing the natural frequency of the rotor. Therefore, the rotation speed can be adjusted to be lower or high- er than the resonance speed to damp the vibration of the pulverator. But the natural frequency of the rotor is not constant, especially after long time grinding. On account of the array of the hammer slices and other factors, the hammer slices usually abrade unevenly, which causes the eccentricity of the rotor and then make the grinder vibrate[9]. Therefore, studying the characteristics when the hammer slices abrade is quite practical for taking better action to damp the vibration of the pulverator.
Virtual prototype (VP) technology is a process ofusing a CAD model, instead of a physical prototype, to test and evaluate the specific characteristics of a product or a manufacturing process[1]. The develop- ment of hardware and software of computer and network technology widely expands the application of VP. Meanwhile, traditional optimization and simula- tion techniques provide essential foundation to realize VP. Except for the hi-tech field, VP technology has also been applied to agricultural machinery design increasingly[10]. The authors attempt to apply VP technology to the engineering analysis of general machinery.
In this paper a simplified dynamic model for the rotor of the feed-grinder was developed based on rotor dynamics and the corresponding virtual prototype of the rotor was generated by using MDT and vN4D. By simulating the VP under different abrasion situations, the vibration characteristics of the rotor when the hammer slices abrade was analyzed.
1 Simplified model of the rotor
The rotor of SFSP112×30 feed-grinder with the symmetrical hammer slice array is shown in Fig.1. It consists of spindle, ball bearings, disk boards, ham-mer slices, pins and sleeves and its full-load rotational speed is 1480 r/min. So its frequency of the forced vibration should be 1480/60=24.67Hz.
Fig.1 Diagram of the rotor of SFSP112×30 feed-grinder
Based on the simplification principle of lumped parameter method[2]that the simplified model should have the same gross mass, moment of inertia and posi- tion of centroid to the original, the rotor of the pulver- ator was simplified into a one-span six-disc rotor system with two springs' support, as shown in Fig.2. The right end of the spindle and the center of each ball bearing and disk board are chosen as the positions of six disks. Fig.2 Simplified model of the rotor
The ball bearing is generally considered that it only provides stiffness because of its small damping[3]. In the system each self-aligning bearing on one side of the spindle is modeled as a spring, the stiffness of which can be calculated in the light of the following equation[4]:
2 Virtual prototype of the rotor
The 3D model of the rotor which only includes parts related to the simulation was built in MDT, a three- dimensional modeling software. The initialization of VP was fulfilled in vN4D, including importing the 3D model from MDT, modifying constraints between the parts and appending motor power[5]. Some important steps are listed below:
1) Instead of flat key joint each disk board is attached to the spindle by rigid joint which locks two bodies together absolutely.
2)Rigid jointis also used to fasten the pin with the disk board.
3) Because sleeves are used to limit the positions of the hammer slices, rigid joint is set as the constraint between the sleeve and the pin.
4) Constraint between the hammer slice and the pin is revolution joint, which is used to limit the motion of two bodies so that one body only rotates about a certain axis with respect to the other body.
5) The ball bearings are replaced by bushing constraint which can simulate the function of ball bearings. Eq. (1) is set as the stiffness function parameter of bushing constraint.
6) A motor constraint is added to the left end .
3 VP simulation and analysis
In order to accelerate the simulation speed, only those circumstances without external applied load were simulated. Meanwhile, since the pulverator needs a very short accelerating time, only the stage when the rotor runs stably is considered in this paper. As a result of the permutation of the hammer slices, the axial distribution of the material in the mill housing is often inhomogeneous and so does the wear extent of each hammer slice along the spindle. There- fore, the centroid of the rotor deviates from its original position. According to the probable deviation direction of the centroid, namely, radial, axial and both directions, four kinds of abrasion forms were specified. Furthermore, to contrast with the vibration under abrasion situations the performance with undamaged hammer slices was also simulated. The results of simulation are listed in Table 1.Table 1 VP simulation results with five abrasion forms of hammer slices
The diagrammatic sketch of the assumed abrasion forms is shown in Fig. 4. The four pin-and-sleeve groups were labeled fromⅠtoⅣclockwise when viewed from the axial direction and the hammer slices in each group are all marked from 1 to 8 parallel to the spindle. In Fig.4a the worn extent of each hammer slice is equal. In Fig. 4b the worn extent of each hammer slice in one group is unequal while the corresponding hammer slices in groupⅠandⅢhave the same worn extent. As for Fig.4c and Fig.4d the worn extent of the hammer slice is not identical entirely.
Figure 5 shows the vibration acceleration and power spectrum diagram (PSD) of the ball bearings collected in the process that the VP of the rotor ran for one second after it had wheeled for 14 s. Real line represents the vibration response of the left bearing and dashed line represents that of the right one. Fig.4 Sketch of abrasion forms.
The component of the vibration frequency changes little before and after the hammer slices are worn out. But the intensity at each frequency is quite different Fig.5 Vibration response of each bearing from the corresponding frequency of undamaged rotor.
At low-frequency stage the intensity strengthens and weakens at high-frequency stage. Especially the intensity under " even abrasion" situation changes much greater than that under other situations. And the same conclusion can be found for the vibration amplitude of the rotor. By contrasting Fig.5b and Fig.5c, it can be inferred that the radial offset of the centroid badly destroyed the balance of the rotor. This conclusion can also be acquired by contrasting Fig.5d and Fig.5e because the radial offset quantity of "adjacent uneven abrasion" is obviously larger than that of "asymmetric uneven abrasion". The intensity at the forced vibration frequency (24.67Hz) increases much more sharply under " even abrasion" and " adjacent uneven abrasion" situations while it changes a little under the other two situations.
4 Conclusions
1) The abrasion form of hammer slice does not influence the makeup of the vibration frequency of the rotor. However it really brings obvious changes to the intensity of the frequency, which exhibits that the intensity of low-frequency stage strengthens while that of high-frequency stage weakens.
2) The radial offset of the centroid can markedly disrupt the balance of the rotor compared with the axial offset. The vibration amplitude and intensity both increase greatly when the center of mass deviates radially.
3) The intensity at the forced vibration frequency is greatly raised when either the hammer slices wear evenly or the adjacent hammer slice groups wear unevenly with respect to other abrasion forms. It owes to the larger radial centroidal offset of these two abrasion forms that results in the imbalance of the rotor.
4) Based on these conclusions above, in order to damp the vibration of the feed-grinder the centroid of the rotor should not present radial offset. So the rotor needs to be well balanced especially in the dynamic balance test before going into operation.
目錄
一.設(shè)計目的及意義 2
二.設(shè)計的基本條件及技術(shù)要求 2
三.總體設(shè)計說明及計算 2
3.1傳動裝置 3
3.1.1電機選擇(Y系列三相交流異步電動機) 3
3.1.2 V帶設(shè)計 3
3.2零件計算及選擇 5
3.2.1軸的設(shè)計 5
3.2.2錘片的設(shè)計 6
3.2.3 錘片架的設(shè)計 7
3.2.4 篩片的設(shè)計 7
3.2.5校核 8
3.2.6主要尺寸及數(shù)據(jù) 9
3.2.7錘片式粉碎機常用故障分析 9
3.2.8 錘片式粉碎機安裝,技術(shù)參數(shù)分析及其檢修 10
四.評價 11
參考文獻 12
一.設(shè)計目的及意義
在現(xiàn)代人們的生活中,機器已經(jīng)進入了大部分家庭中,它幫助我們完成各種工作,讓我們可以生活的更加輕松和方便?,F(xiàn)在家庭中,有許多的小型機器,在農(nóng)業(yè)生產(chǎn)、房屋建設(shè)中,機器更是不可或缺的幫手。現(xiàn)在人們已經(jīng)很習(xí)慣機器給我們打來的巨大便利,所以會有更多的機器的產(chǎn)生。同樣的,在畜牧喂養(yǎng)上,人們也發(fā)明了很多機器,例如:自動喂水、喂食機,自動擠奶機,在雞舍里會有自動控制溫度和濕度的機器。但是現(xiàn)在的飼料有時買回來不能直接就喂給動物,需要切碎后喂食,所以我就有想法,可以做一個自動切碎飼料的機器,這樣可以使人們的工作輕松、方便,也可以節(jié)省很多時間。
二.設(shè)計的基本條件及技術(shù)要求
轉(zhuǎn)子直徑:560mm 錘篩間隙:5mm 小帶輪轉(zhuǎn)速:3800r/min 篩孔直徑:760mm
錘片數(shù):16 篩孔數(shù)量:0.75 篩片寬度:200mm 外型尺寸:320寸
動力:7.5kw 生產(chǎn)能力:600公斤/時
工作條件:連續(xù)單向運轉(zhuǎn),工作時有輕微振動,使用期限為10年,小批量生產(chǎn),每天工作時間為8小時。
三.總體設(shè)計說明及計算
錘片式飼料粉碎機的主要結(jié)構(gòu)有:機架、粉碎箱、主軸、錘片架、錘片、進料口、出料口等組成。
3.1傳動裝置
3.1.1電機選擇(Y系列三相交流異步電動機)
配用動力機械的功率(N)的大小,要根據(jù)粉碎機的生產(chǎn)能力(Q)來決定,不宜過大或過小。一般應(yīng)按下式計算:N=(6.4---10.5)Q。N的單位是千瓦,Q的單位是噸/小時。如要求粉碎的較細,系數(shù)的值可取大一點,如要求粉碎的較粗,系數(shù)的值可取小一點。本粉碎機加工的是谷物類飼料,對加工的飼料粉碎程度有多種選擇,故選擇參數(shù)較大一些,這里選擇10,加工能力為0.6噸/小時,所以配用的電機功率為N=6kw 查找書 機械設(shè)計課程設(shè)計,根據(jù)電機選擇標(biāo)準選擇N=7.5kw。具體參數(shù)如下:
型號=Y132S2-2
額定功率\kw=7.5
同步轉(zhuǎn)速\r/min=3000
滿載轉(zhuǎn)速\r/min=2900
滿載時效率\%=86.2
滿載功率因數(shù)\cosθ=0.88
堵轉(zhuǎn)電流/額定電流= 7
堵轉(zhuǎn)轉(zhuǎn)矩/額定轉(zhuǎn)矩=2
最大轉(zhuǎn)矩/額定轉(zhuǎn)矩=2.2
技術(shù)數(shù)據(jù):額定功率() 7.5 滿載轉(zhuǎn)速(r/min)2900
額定轉(zhuǎn)矩()2.0 最大轉(zhuǎn)矩()2.2
3.1.2 V帶設(shè)計
外傳動帶選為 普通V帶傳動:
主軸帶輪轉(zhuǎn)速:
=V*60*1000/3.14*290
=45*60*1000/3.15*290
=2965r/min
1. 確定V帶型號
工作情況系數(shù)K 由書 機械設(shè)計 表6-9 K=1.2
計算功率
V帶型號 根據(jù)p輪和n知為A型
2. 確定帶輪基準直徑、
=100mm
=(n/)
=1440/2965*100
=48.56
取整 =50mm
3. 驗算帶速 v
v=**n/60000
=3.14*100*1440/60000
=7.53m/s
要求帶轉(zhuǎn)速在5—25m/s范圍
4. 確定V帶長度L和中心距a
初取中心距:a=700mm,初算帶的基準長度L
L=2a+(+)/2+(-)/4a
=2*700+3.14*(100+95)/2+(100-95)/4*700
=1706.1mm
按書 機械設(shè)計 表6-5 取整=1800mm
a=a+(-L)/2
=700+(1800-1706)/2
=747mm
5. 驗算小帶輪包角
α=180-(-)/a*57.3=179.6>120
6. 確定V帶根數(shù)
單根V帶實驗條件下許用功率查
=1.15kw
傳遞功率增量△查表知:包角系數(shù)=1 長度系數(shù)=1.01
Z=/(+△)//
=8.25/(1.15+0.13)/1/1.01
=6.38
7. 計算單根V帶初拉力,由式(6-25)得
q由書 機械設(shè)計 表6-6查得
8. 計算帶傳動作用在軸上的載荷,有式(6-26)得
9. 確定帶輪的結(jié)構(gòu)尺寸
小帶輪基準直徑=50mm 采用實心式結(jié)構(gòu)。大帶輪基準直徑=100mm,采用孔板結(jié)構(gòu)。
3.2零件計算及選擇
3.2.1軸的設(shè)計
1.選擇軸的材料及熱處理
根據(jù)粉碎機轉(zhuǎn)子的工作強度,選擇常用材料45鋼,調(diào)質(zhì)處理
2.初估軸徑
按扭矩初估軸的直徑,查書 機械設(shè)計 表11-2,得c=107至118,考慮到安裝聯(lián)軸器的軸段僅受扭矩作用.取c=117則:
Dmin=15mm
3.初選軸承
Ⅰ軸選軸承為61805
根據(jù)軸承確定各軸安裝軸承的直徑為 D=25mm
4.確定尺寸
⑴各軸直徑的確定
初估軸徑后,句可按軸上零件的安裝順序,從左端開始確定直徑.該軸軸段1安裝軸承61805,故該段直徑為25mm。2段裝軸承,為了便于安裝,取2段為31mm。計算得軸肩的高度為3mm,3段安裝螺帽,其固定錘架盤的作用。定為36mm。4段裝鐵錘架,直徑為40mm。5段安裝螺帽和三段相同,六段安裝毛氈,起防止飼料粉進入軸承的作用,取6段31mm。7段裝小帶輪,取為25mm>dmin 。
⑵各軸段長度的確定
軸段1的長度為軸承61805的寬度和軸承到箱體外壁的距離取L1=40mm。2段的寬度取為L2=15mm。3段的長度是螺紋帽的寬度L3=10mm,4段為粉碎機中最關(guān)鍵的部分,該長度對飼料粉碎機的生產(chǎn)效率影響很大,根據(jù)加工要求取:L4=150mm。L5和L3同寬取L5=10mm。L6=15mm,7段同小帶輪連接,取L7=80mm。
⑶軸上零件的周向固定
為了保證良好的對中性,帶輪和錘片架與軸選用過盈配合H7/r6。與軸承內(nèi)圈配合軸勁選用k6,齒輪與大帶輪均采用A型普通平鍵聯(lián)接,分別為10*146 GB1096-1979及鍵12*80 GB1096-1979。
⑷軸上倒角與圓角
為保證6008軸承內(nèi)圈端面緊靠定位軸肩的端面,根據(jù)軸承手冊的推薦,取軸肩圓角半徑為1mm。其他軸肩圓角半徑均為2mm。根據(jù)標(biāo)準GB6403.4-1986,軸的左右端倒角均為1*45。
3.2.2錘片的設(shè)計
由國家機械行業(yè)標(biāo)準規(guī)定了錘片的型式,規(guī)格和設(shè)計要求。根據(jù)本機的設(shè)計要求選擇
I型,其具體設(shè)計圖形如下:
具體參數(shù)如下:a=120 b=950.5 c=40 d=16.5 e=3.5
由于錘片是粉碎機加工的核心部件,所以要求較高。本錘片選擇的金屬材料是65Mn鋼,且經(jīng)過熱處理。熱處理淬火區(qū)硬度為50-57HRC,非淬火區(qū)硬度不超過28HRC。其淬火
區(qū)如下圖所示:
本錘片的設(shè)計使用壽命為大于400h,質(zhì)量為0.2kg,錘片的寬度定位3mm,錘片的個數(shù)定位18個,且每個錘片之間的相差質(zhì)量小于5g.
3.2.3 錘片架的設(shè)計
轉(zhuǎn)盤架的直徑設(shè)為290mm,厚度為4mm.其質(zhì)量為0.4kg具體形狀如下圖:
計算出轉(zhuǎn)子的工作直徑為430mm
3.2.4 篩片的設(shè)計
按照國標(biāo)GB-T3943-1983的設(shè)計標(biāo)準,粉碎機篩片應(yīng)按GB/T3943的Ⅰ型制造。優(yōu)先采用Ⅰa型篩片。選取篩孔的直徑為4(篩片號為40),孔間距為5mm,錘篩間距6mm,篩分面積比為58:40.其尺寸由轉(zhuǎn)子的工作直徑可算出,篩片的長度為220*∏=691.15=690mm,曬片的厚度定位1.5mm.篩片的寬度定為200mm。
3.2.5校核
1.鍵的校核
鍵1 10×8 L=80 GB1096-79
則強度條件為
查表許用擠壓應(yīng)力
所以鍵的強度足夠
鍵2 12×8 L=63 GB1096-79
則強度條件為
查表許用擠壓應(yīng)力
所以鍵的強度足夠
2.聯(lián)軸器的選擇
聯(lián)軸器選擇為TL8型彈性聯(lián)軸器 GB4323-84
3.滾動軸承的潤滑
因潤滑油中的傳動零件的圓周速度V>>1.5~2m/s所以采用飛濺潤滑。
3.2.6主要尺寸及數(shù)據(jù)
箱體尺寸:
箱體壁厚
箱蓋壁厚
箱座凸緣厚度b=25mm
箱蓋凸緣厚度b1=25mm
箱座底凸緣厚度b2=25mm
地腳螺栓直徑df=M10
地腳螺栓數(shù)目n=4
軸承旁聯(lián)接螺栓直徑d1=M10
聯(lián)接螺栓d2的間距l(xiāng)=160mm
軸承端蓋螺釘直徑d3=M8
定位銷直徑d=6mm
軸承旁凸臺半徑R1=15mm
凸臺高度根據(jù)低速軸承座外半徑確定
外箱壁至軸承座端面距離L1=40mm
大齒輪頂圓與內(nèi)箱壁距離△1=10mm
齒輪端面與內(nèi)箱壁距離△2=10mm
箱蓋,箱座肋厚m1=m=7mm
軸承端蓋外徑D2 :凸緣式端蓋:D+(5~5.5)d3
以上尺寸參考書 機械設(shè)計課程設(shè)計
3.2.7錘片式粉碎機常用故障分析
錘片式粉碎機廣泛用于糧食和飼料的粉碎,現(xiàn)將粉碎機常見的幾種故障產(chǎn)生原因分析如下:
1. 錘片嚴重磨損的原因:①表面熱處理不當(dāng),因錘片是用優(yōu)質(zhì)鋼制成,頭部經(jīng)滲碳、淬火處理,淬火硬度為HRC60-65,若熱處理不當(dāng),使用中會很快磨損;②錘片的厚度小,因粉碎機常用矩形雙銷孔錘片,其使用壽命為200-500小時,厚度小雖可減輕重量而使粉碎生產(chǎn)率提高,但使用壽命短,一般粉碎糧食的錘片選用2-3mm,粉碎豆餅及礦物的選用6-8mm;③吸風(fēng)量太大,因錘片式粉碎機一般都采取吸風(fēng)措施來降低機內(nèi)溫度、濕度,并防止粉塵外泄,但吸風(fēng)量太大也會造成錘片不均勻磨損,應(yīng)適當(dāng)控制風(fēng)量;④錘片與篩片的間隙太小,一般應(yīng)保持在4-12mm,粉碎谷物為4-8mm,粉碎秸稈為10-14mm。
2. 機器運轉(zhuǎn)中有震動和噪音的原因:①機座安裝不牢固,緊固螺絲松動;②錘片磨損后沒有同時成對更換,或錘片磨損不均勻,致使錘片重量相差大;③轉(zhuǎn)子轉(zhuǎn)動不平衡,轉(zhuǎn)速超過額定轉(zhuǎn)速;④物料中混有石塊或金屬等異物而引起噪音,同時會損壞錘片、篩片。
3. 生產(chǎn)率顯著下降的原因:①電動機功率不足或配套動力不合適;②轉(zhuǎn)子轉(zhuǎn)速過低或皮帶打滑,應(yīng)檢查皮帶輪尺寸是否符合要求,或調(diào)整皮帶松緊度;③喂料不勻使粉碎機轉(zhuǎn)速不穩(wěn),導(dǎo)致生產(chǎn)率下降;④錘片嚴重磨損,錘與篩的間隙過大;⑤物料含水量過高。
4. 成品過粗的原因:①篩片和篩架貼合不嚴或側(cè)面間隙過大;②篩片磨損嚴重或有孔洞,應(yīng)修補孔洞或更換新篩片。
3.2.8 錘片式粉碎機安裝,技術(shù)參數(shù)分析及其檢修
一)安裝
1、 粉碎機長期固定使用時,應(yīng)將粉碎機架安裝在水泥基礎(chǔ)上,也可將粉碎機單獨固定在車架上使用。
2、 所有電器設(shè)備及線路必須安裝正確可靠。
3、 安裝后各轉(zhuǎn)動部件要運轉(zhuǎn)靈活,進行空運轉(zhuǎn)半小時,檢查有無卡碰及不正常響聲,連接是否牢靠。
4、 三角帶轉(zhuǎn)動部分必須安裝防護罩,尺寸見附圖。安裝固定點為機器軸承座固定螺栓和電機座固定螺栓。
二)錘片式粉碎機是飼料加工機械中主要耗能設(shè)備, 它的性能好壞直接影響生產(chǎn)率和單位能耗。影響粉碎機工作性能的因素很多, 其中最主要是粉碎機本身的結(jié)構(gòu)參數(shù)。因此, 研究和合理選擇錘片式粉碎機結(jié)構(gòu)參數(shù), 對提高性能指標(biāo)和降低成本具有重要的經(jīng)濟意義。影響錘片式粉料機性能的技術(shù)參數(shù)較多。錘片末端線速度是影響粉碎機工作性能的重要因素。錘片式粉碎機的工作原理, 靠高速旋轉(zhuǎn)的錘片對物料打擊、剪切和挫擦等綜合作用, 把錘片的功能變?yōu)槲锪系姆鬯槟?。錘片的功能與線速度平方成正比, 大量試驗證明, 在一定范圍內(nèi)提高線速度可以提高生產(chǎn)率和度電產(chǎn)量, 并減少粉料的粗細度。近年來, 國內(nèi)外錘片式粉碎機的線速度都在提高。
三)飼料粉碎機的檢修的三大點
一、篩網(wǎng)的修理和更換。篩網(wǎng)是由薄鋼板或鐵皮沖孔制成。當(dāng)篩網(wǎng)出現(xiàn)磨損或被異物擊穿時,若損壞面積不大,可用鉚補或錫焊的方法修復(fù);若大面積損壞,應(yīng)更換新篩。安裝篩網(wǎng)時,應(yīng)使篩孔帶毛刺的一面朝里,光面朝外,篩片和篩架要貼合嚴密。環(huán)篩篩片在安裝時,其搭接里層茬口應(yīng)順著旋轉(zhuǎn)方向,以防物料在搭接處卡住。
二、軸承的潤滑與更換。粉碎機每工作300小時后,應(yīng)清洗軸承。若軸承為機油潤滑,加新機油時以充滿軸承座空隙1/3為宜,最多不超過1/2,作業(yè)前只需將常蓋式油杯蓋旋緊少許即可。當(dāng)粉碎機軸承嚴重磨損或損壞,應(yīng)及時更換,并注意加強潤滑;使用圓錐滾子軸承的,應(yīng)注意檢查軸承軸向間隔,使其保持為0.2-0.4毫米,如有不適,可通過增減軸承蓋處紙墊來調(diào)整。
三、齒爪與錘片的更換。粉碎部件中,粉碎齒爪及錘片是飼料粉碎機中的易損件,也是影響粉碎質(zhì)量及生產(chǎn)率的主要部件,粉碎齒爪及錘片磨損后都應(yīng)及時更換。齒爪式粉碎機更換齒爪時,應(yīng)先將圓盤拉出。拉出前,先要開圓盤背面的圓螺母鎖片,用鉤形扳手擰下圓螺母,再用專用拉子將圓盤拉出。為保證轉(zhuǎn)子運轉(zhuǎn)平衡,換齒時應(yīng)注意成套更換,換后應(yīng)做靜平衡試驗,以使粉碎機工作穩(wěn)定。齒爪裝配時一定要將螺母擰緊,并注意不要漏裝彈簧墊圈。換齒時應(yīng)選用合格件,單個齒爪的重量差應(yīng)不大于1.0-1.5克。
錘片式粉碎機的錘片有的是對稱式,當(dāng)錘片尖角磨鈍后,可反面調(diào)角使用;若一端兩角都已磨損,則應(yīng)調(diào)頭使用。在調(diào)角或調(diào)頭時,全部錘片應(yīng)同時進行,錘片四角磨損后,應(yīng)全部更換,并注意每組錘片重量差不得大5克;主軸、圓盤、定位套、銷軸、錘片裝好后,應(yīng)做靜平衡試驗,以保持轉(zhuǎn)子平衡,防止機組振動。此外,固定錘片的銷軸及安裝銷軸的圓孔由于磨損,銷軸會逐漸磨細、圓孔會逐漸磨大,當(dāng)銷軸直徑比原尺寸縮小1毫米,圓孔直徑較原尺寸磨大1毫米時,應(yīng)及時焊修或更換。
四.評價
我設(shè)計的錘片式飼料粉碎機我個人覺得不是做的很好,錘片之間的距離分配做的不是很適合??赡茉诠ぷ鞯臅r候不能達到太細的粉碎程度。
參考文獻
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