外文翻译--锤片式粉碎机

附录 1 译 文 摘 要 :锤片磨损会破坏锤片式粉碎机转子的平衡 ,加剧转子振动。该文的研究目的是基于虚拟样机技术探讨锤片磨损对转子振动的影响规律。采用 MDT和 vN4D 建立了 SFSP11230 型锤片式粉碎机转子的虚拟样机模型 ,对不同锤片磨损情况下粉碎机转子的振动进行了仿真。结果表明 :锤片磨损后 ,转子振动频率组成变化不大 ,而振动幅值和强度变化较大 ,其中低频段振动强度增强 ,高频段振动强度降低 ；导致转子质心径向偏移的锤片磨损使转子振动幅值和强度均变大 ,而导致质心轴向偏移的磨损对转子振动影响不大 ；同样由于转 子质心的径向偏移 ,转子受迫振动频率强度增加较多。因此 ,为了降低子运转时的振动 ,最好避免转子质心发生径向偏移。 关键词 :锤片式粉碎机 ； 锤片 ； 虚拟样机 (VP)； 磨损 ； 振动 简 介 能从谷物中的营养提取出来的饲料粉碎机已经发展很多年了。但是因为他只能处理特殊的原料，像谷类食品和矿石，所以除了丕林岛（地名）的少数人在研究饲料粉碎机外，很少人去研究他。尽管饲料粉碎机已经可以解决很多问题，比如振动、噪音、堵塞，用他特有的结构来解决问题，而且可以连续工作并达到一定的精度。 虽然一 些方法，比如比较低的回转速度，宽的转子直径被采用，好转了他的性能，但是那些问题不能扯得的被解决。最近，分析了饲料粉碎机在工作状态下转子的转速，旋转的速度能被粉碎机控制在稍低或者稍高的程度。转子的转速在正常工作下都是不变的，除了在长时间工作摩擦后。由于锤片的排列或者是其他的因素，产生转子的离心力不固定，所以锤片的磨损是不均衡的，因此，我们要学习掌握锤片要磨损时候的特征，为了使粉碎机振动保持稳定。 实质上的原型技术（ VP）是一个用 cad 加工程序代替真实的模型，为了测试这种产品的特性和特征。这就像电脑的硬件和软件 的发展，网络技术通过 vp 技术开展起来。同时，传统的模拟技术对 VP 的认识理解很有基础。除了高科技种田， VP 技术还适用于日益发展的农业机械设计。作者努力的将VP 技术应用于工程分析技术。 对于饲料粉碎机中转子单一的动力模型，被用来发展转子动力学，转子有效的运动模型被 MDT 和 VN4D 当做虚拟原型来用。 VP 技术模拟不同情况的磨损下，研究转子转动时的震动和锤片磨损的分析。 1.单一化转子的模型 SFSP11230 的转子的锤片被均匀的排列，它是由定子、滚球轴承、锤片、轴子组成，最大转速为 1480r/min。所以 它的最大频率应该是 1480/60=24.6Hz。 图一 SFSP112 30 的转子图表 基于集总的单一化原则叁数方法 被单一化的模型应该有同样的总质量，瞬间的转动惯量有最初的质心位置决定。粉碎机的转子被单一化的分别运行在六个圆盘里。在这系统里，每一个自我排列的定子，会在压力的作用下自己运行到指定的位置，能够计算出他们最后的位置。 2.转子的虚拟原型 转子的 3D模型需要建立在一个 MDT的三维建模软件上， VP的技术原本是用来实现 Vn4D的，其中包括重要的参数从转子的发动机的功率。一些重要参数列出如 下 （ 1） 定子连接上，平键连接被强固连接完全代替； （ 2） 强固连接也被用来连接圆盘； （ 3） 因为轴子被用来限制锤片的位置，所以强固连接被用来限制轴子和锤片的位置； （ 4） 在锤片和螺钉通过强固连接，来限制彼此的旋转动作，来完成轴的夹紧； （ 5） 球轴承被轴衬所代替，轴衬确定参数。 （ 6） 电动机的限制被增加到左边的结束，他的参数、转力矩输出功能被设置在平衡的感电电动机上 3.VP技术 的模拟分析 为了要加速模拟速度，唯一的没有外部的那些环境应用的负荷被模拟，同时，粉碎机需要非常短的加速时间，没有负载的环境是不可能的 。粉碎机需要加速的这段时间内，转子跑到他的位置上。 锤片的排列的结果，在研磨中起作用的轴通常用不同种型号，锤片通过定子的排列的长短来确定。因此质心上的转子偏离最初的位置。根据概率公差，质心的方向也就是轴运动的方向，磨损的方向是在情理之中的。此外，和磨损情形对比，锤片的磨损也是模拟的。 根据模拟的结果列出表 1 磨损的图被展现在图 4 上，第四个锤片和轴子被标在 和 上， 当从轴向观察，每组的锤片，每组都标着 1 到 8 平行的定子，在图 4A 磨损程度每个锤片是平等的。图 4B 条的磨损程度，每个锤片的一组是不平等的，而相应 的锤片组有 ， 同样的磨损程度。至于 Fig.4c 和 Fig.4d 的磨损程度的锤片是不相同完全。图 5 显示振动加速度和动力频谱图的球轴承收集在这一过程中，该转子转过第一第二轮之后， 14 号实线代表的振动响应左轴承和虚线代表是正确的。 图 4 示意图磨损形式。锤片的磨损的主体部分的振动频率之前和之后没有变化。 但强度在每一个频率是完全不同的图 5 振动响应每个轴承从相应的频率，损坏转子。在低频阶段加强和强度削弱了在高频率的阶段。特别是根据 “甚至磨损 ”形势的变化很大大于其他情况下。和同样的结论可以发现振动扩增管转子。通过 对比 Fig.5b 和 Fig.5c ， 可以推断，径向偏移严重破坏了平衡的转子。这一结论也可以通过 Fig.5d 和 Fig.5e 的对比得到。由于径向偏移量 “相邻不均匀磨损 “显然是大于 “不对称不均匀磨损 ” 。强度在强迫振动频率（ 24.67 赫兹）增加多少更根据 “甚至耐 磨”和“相邻不均匀磨损”的情况，虽然有点变化根据以上两种情况对比。 4 结论 （ 1）磨损形式并不影响能使锤片的振动频率改变的转子。然而，它确实带来了明显的变化强度的频率，其中的强度低频率的阶段，同时加强这一高频率阶段的削弱。 （ 2）径向 偏移现实出来是不稳定的转子相对于轴向偏移。振幅和强度大大增加时质心偏离径向。 （ 3）强度的强迫振动频率大大提高时，会出现无论是锤片磨损均匀或邻近群体锤片磨损不均等方面的磨损情况。它需要较大的径向力来抵消这两个磨损形式，结果是不稳定的转子。 （ 4）基于以上这些结论，为了控制饲料粉碎机的转子的振动，饲料粉碎机的转子不应径向偏移。因此，转子需要很好的平衡特别是需要在达到动态平衡之前进入正常的运行。 附录 2 英文参考资料 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 SFSP11230 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 technologyJ. 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 vibrate9. 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 process1. 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 increasingly10. 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 SFSP11230 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 SFSP11230 feed-grinder Based on the simplification principle of lumped parameter method2that 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 damping3. 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 equation4: 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 power5. 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 from to clockwise 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 group and have 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 (2