叉车主体结构模态分析与减振设计
发布时间：2019-04-16 20:23
【摘要】：结构动力学性能是叉车整体性能中十分重要的因素。振动带来的危害长期影响着叉车的寿命和舒适度，此外，剧烈的振动还会导致零件产生裂纹、齿轮传动失效、紧固零件松脱。随着市场竞争的加剧以及振动噪声控制技术的不断发展，对叉车舒适性的要求也越来越严格。在国内，叉车结构动力学性能的研究一直未得到重视，使得自主品牌的叉车与国外同类产品在振动表现上差距较大。为了避免叉车在正常运行中的共振现象、确保其安全可靠，并提升舒适度，，本文深入研究了其结构的动态特性，并利用结构动力学修改对叉车车架结构进行了优化。 车架和护顶架是叉车主体结构，其中车架是主要承载基体，护顶架是与驾驶室结合最紧密的大型结构，两者的模态不仅反映了叉车的整体动态性能，而且是控制整车振动特性的关键。叉车振动系统的振源主要是发动机和坑洼路面，本文主要研究发动机激励下叉车的动态特性，降低振动水平的方法是避免发动机常用激励频率跟车架或护顶架固有频率接近所引起的共振。利用解析法和试验法获得叉车车架和护顶架的模态参数，深入研究车架和护顶架的动态特性后，将车架结构合理的改进，改善了车架的动态特性，降低了振动水平，增加了整车的舒适性。 对该型号叉车运行时的振动信号进行了采集，找出振动能量最大时刻的信号并侧重其进行分析。然后对护顶架和车架分别做了模态分析，将解析和测试得到模态参数与现场振动检测结果相比较。在此基础上，确定该型号叉车振动主要原因是护顶架和车架在发动机怠速附近激励下产生同时共振，且由于共振频率在发动机常用转速激励范围内，导致叉车长时间共振。最后，对车架做了结构动力学修改，并通过实车验证了方案可以有效降低叉车振动水平。本文所述的减振设计方法全面考虑了振动信号特点和模态参数，对叉车护顶架与车架两个主要结构同时进行了分析，为叉车振动控制的研究提供了经验和参考。
[Abstract]:Structural dynamic performance is a very important factor in the overall performance of forklift truck. The damage caused by vibration affects the life and comfort of forklift truck for a long time. In addition, severe vibration will lead to cracks in parts, failure of gear transmission and loosening of fastening parts. With the intensification of market competition and the continuous development of vibration and noise control technology, the comfort requirements of forklift trucks are becoming more and more strict. In China, the research on the dynamic performance of forklift structure has not been paid attention to, which makes the vibration performance of forklift truck with its own brand is far from that of other similar products in foreign countries. In order to avoid resonance phenomenon of forklift truck in normal operation, ensure its safety and reliability, and improve comfort, the dynamic characteristics of its structure are deeply studied in this paper, and the structure of forklift truck frame is optimized by structural dynamic modification. The frame and roof protection frame are the main structure of forklift truck, in which the frame is the main bearing matrix, and the roof frame is the large structure which is most closely combined with the cab. The modes of the two modes not only reflect the overall dynamic performance of the forklift truck, but also reflect the dynamic performance of the forklift truck. And it is the key to control the vibration characteristics of the whole vehicle. The vibration source of forklift vibration system is mainly engine and pothole pavement. This paper mainly studies the dynamic characteristics of forklift under engine excitation. The way to reduce the vibration level is to avoid the resonance caused by the common excitation frequency of the engine close to the natural frequency of the frame or roof frame. The modal parameters of forklift truck frame and roof guard frame are obtained by analytical method and test method. After deeply studying the dynamic characteristics of forklift frame and roof guard frame, the frame structure is improved reasonably, the dynamic characteristics of the frame are improved, and the vibration level is reduced. Increased the comfort of the whole car. The vibration signal of the forklift truck is collected, and the signal of the maximum vibration energy is found and analyzed. Then the modal analysis of the roof-protecting frame and the frame is carried out, and the modal parameters obtained from the analysis and test are compared with the results of vibration detection in the field. On this basis, the main reason for the vibration of the forklift is the simultaneous resonance caused by the excitation of the hood and the frame near the idle speed of the engine, and the long-term resonance of the forklift is caused by the resonance frequency within the excitation range of the common speed of the engine. Finally, the structural dynamics of the frame is modified, and it is verified that the scheme can effectively reduce the vibration level of forklift truck. The vibration reduction design method described in this paper takes the vibration signal characteristics and modal parameters into account, and analyzes the two main structures of forklift roof support frame and truck frame simultaneously, which provides experience and reference for the study of forklift vibration control.
【学位授予单位】：中国计量学院
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH242
[Abstract]:Structural dynamic performance is a very important factor in the overall performance of forklift truck. The damage caused by vibration affects the life and comfort of forklift truck for a long time. In addition, severe vibration will lead to cracks in parts, failure of gear transmission and loosening of fastening parts. With the intensification of market competition and the continuous development of vibration and noise control technology, the comfort requirements of forklift trucks are becoming more and more strict. In China, the research on the dynamic performance of forklift structure has not been paid attention to, which makes the vibration performance of forklift truck with its own brand is far from that of other similar products in foreign countries. In order to avoid resonance phenomenon of forklift truck in normal operation, ensure its safety and reliability, and improve comfort, the dynamic characteristics of its structure are deeply studied in this paper, and the structure of forklift truck frame is optimized by structural dynamic modification. The frame and roof protection frame are the main structure of forklift truck, in which the frame is the main bearing matrix, and the roof frame is the large structure which is most closely combined with the cab. The modes of the two modes not only reflect the overall dynamic performance of the forklift truck, but also reflect the dynamic performance of the forklift truck. And it is the key to control the vibration characteristics of the whole vehicle. The vibration source of forklift vibration system is mainly engine and pothole pavement. This paper mainly studies the dynamic characteristics of forklift under engine excitation. The way to reduce the vibration level is to avoid the resonance caused by the common excitation frequency of the engine close to the natural frequency of the frame or roof frame. The modal parameters of forklift truck frame and roof guard frame are obtained by analytical method and test method. After deeply studying the dynamic characteristics of forklift frame and roof guard frame, the frame structure is improved reasonably, the dynamic characteristics of the frame are improved, and the vibration level is reduced. Increased the comfort of the whole car. The vibration signal of the forklift truck is collected, and the signal of the maximum vibration energy is found and analyzed. Then the modal analysis of the roof-protecting frame and the frame is carried out, and the modal parameters obtained from the analysis and test are compared with the results of vibration detection in the field. On this basis, the main reason for the vibration of the forklift is the simultaneous resonance caused by the excitation of the hood and the frame near the idle speed of the engine, and the long-term resonance of the forklift is caused by the resonance frequency within the excitation range of the common speed of the engine. Finally, the structural dynamics of the frame is modified, and it is verified that the scheme can effectively reduce the vibration level of forklift truck. The vibration reduction design method described in this paper takes the vibration signal characteristics and modal parameters into account, and analyzes the two main structures of forklift roof support frame and truck frame simultaneously, which provides experience and reference for the study of forklift vibration control.
【学位授予单位】：中国计量学院
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH242
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