共查询到18条相似文献，搜索用时 49 毫秒
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在机加工中,对于一些装配工艺精度要求较高,零件直接按图纸尺寸加工难度较大、更换设备又不划算的情况下,如何找到一种装配尺寸链计算方法,可以利用现有设备满足零件的正常批量生产显得尤为重要.分组装配法是将产品组成环公差相对于互换装配法所求公差扩大若干倍,使其达到经济加工精度,装配时先对零件进行测量分组,然后按对应组相配以达到... 相似文献
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产品的装配工艺过程大致包括四个阶段,即装配前的准备工作,装配工作,调整、精度检验和试车及涂装、涂油、装箱。合理选择装配尺寸链的解法,对保证机械产品的装配精度和装配质量、降低产品成本起着决定性的作用。 相似文献
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《中国新技术新产品》2016,(4)
链篦机在工业生产过程中,特别是氧化球团行业是非常关键和重要的。但是在链篦机的设备中,头轮装配是一个非常重要的部件。头轮装配运行和设计的好坏,直接影响着设备的运行状况,因此要对头轮装置进行一定程度的改进。此部件的改进提升了链篦机的整体使用性能,为链篦机争取更大的销售市场提供了有力的保障。 相似文献
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根据自顶向下的设计要求,提出基于映射技术的功能模型向装配模型的转换方法.通过信息实例化及规则表达,保证了映射技术的可行性.通过建立不同的实例库和Mapping表,较好实现了模型信息的转换.通过功能单元映射为装配单元,功能间约束映射为装配连接特征以及装配关系,实现了设计约束的自顶向下传递和功能设计与结构设计的集成.利用二叉树对模型交互进行装配序列化处理,保证了装配模型结构的完整性与可装配性.通过开发原型系统验证了该方法的可行性. 相似文献
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Entity and relation extraction is an indispensable part of domain knowledge graph construction, which can serve relevant knowledge needs in a specific domain, such as providing support for product research, sales, risk control, and domain hotspot analysis. The existing entity and relation extraction methods that depend on pretrained models have shown promising performance on open datasets. However, the performance of these methods degrades when they face domain-specific datasets. Entity extraction models treat characters as basic semantic units while ignoring known character dependency in specific domains. Relation extraction is based on the hypothesis that the relations hidden in sentences are unified, thereby neglecting that relations may be diverse in different entity tuples. To address the problems above, this paper first introduced prior knowledge composed of domain dictionaries to enhance characters’ dependence. Second, domain rules were built to eliminate noise in entity relations and promote potential entity relation extraction. Finally, experiments were designed to verify the effectiveness of our proposed methods. Experimental results on two domains, including laser industry and unmanned ship, showed the superiority of our methods. The F1 value on laser industry entity, unmanned ship entity, laser industry relation, and unmanned ship relation datasets is improved by +1%, +6%, +2%, and +1%, respectively. In addition, the extraction accuracy of entity relation triplet reaches 83% and 76% on laser industry entity pair and unmanned ship entity pair datasets, respectively. 相似文献
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装配体的参数化设计研究 总被引：2，自引：0，他引：2
通过参数化零件的数据关联分析,并将机械产品的装配模型抽象成两个两件的逐层级联关系,从而对零件模型数据进行装配适应性重构,建立起装配节点上的数据继承、传递和零件驱动关系,实现设计参数和几何模型参数的匹配和连接,从而达到整机产品的参数化设计目的,并以减速箱产品为实例,采用Pro/E系统实现了该装配体的参数化设计. 相似文献
