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闭式《轮被广泛的应用在各个领域中,本文以UG软件为平台,对闭式《轮的数控多轴加工工艺进行了分析研究,制定了工艺方案,对其刀具路径进行了合理规划,避免了加工干涉,最后完成了仿真加工,取得了很好的效果。 相似文献
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在机械加工中我们经常会遇到一些比较复杂的三维曲面的加工，如何利用合适的设备，合理的工艺，正确的刀具路径加工是我们一直需要考虑的事情。有一批复杂的零件，需要运用五轴加工中心能很容易加工出来，由于操作车间只有三轴立式加工中心，结果我利用简单的工装，分步加工，合理设计加工工艺，最终用三轴加工中心加工出了这批零件，取得了最大的经济效益！ 相似文献
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数控机床使用的刀具必须具有较高硬度和高耐磨性、足够的强度与韧性以及高的耐热性,还需要较好的工艺性与经济性.刀具的选择和切削用量的确定是齿轮加工工艺中的重要内容,它不仅影响数控机床的加工效率,而且直接影响齿轮的加工质量因此,数控加工中的刀具选择和切削用量确定是在人机交互状态下完成的,这与普通机床加工形成鲜明的对比,同时也要求编程人员必须掌握刀具选择和切削用量确定的基本原则,在编程时充分考虑数控加工的特点,能够正确选择刀刃具及切削用量. 相似文献
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在细长轴的加工过程中,CA6140机床车的应用,基于刀具磨损、变形、震动等因素,致使生产结果存在较高的废品率,针对加工过程中存在的相关问题,需要建立一套具有完整性的工艺方案予以解决,本文从加工误差因素出发,对加工削细长轴时刀具角度的合理选择予以探讨。 相似文献
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顶轴油系统采用恒压变量柱塞泵,并且油站增设蓄能器,从而保证系统油压及流量的稳定性和可靠性。系统控制块采用集中布置、结构紧凑,控制精度高,各轴瓦间的压力波动干扰小。顶轴油系统经优化改造后提高了顶轴油系统的安全性、可靠性。 相似文献
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郭明明 《沈阳体育学院学报》2006,25(5):120-122
难度动作是武术运动员比赛成绩的决定因素。成功完成旋子转体720°接竖叉可获得0．6分的难度得分,而目前该动作的完成情况并不理想,尤其是在落地接竖叉过程中经常出现失误。应用DLT法,对第十届全国运动会女子长拳冠军梅寒完成的旋子转体720°接竖又的落地技术进行分析,旨在揭示动作的运动规律,为教练员以后的训练工作提供科学参考。结论:在整个落地过程中,梅寒始终保持梗头,有利于提高落地的稳定性;梅寒的两臂总是在左脚落地后快速向两侧伸展,两臂的位置,有利于及时调整重心;梅寒的上体从右脚落地瞬间便开始积极地前倾,既提高了落地的稳定性,又加强了对落地的缓冲作用。 相似文献
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最近10年,消费级无人机尤其是四轴飞行器销量大长,降低了遥控飞行的门槛,更多的人得以体验飞行的快乐。也许是常被称为无人机的缘故,四轴飞行器与固定翼遥控模型玩家之间始终有种隔阂,平时不怎么交流,大都各玩各的。如今航模与无人机之间的界限越来越模糊。最近几年,穿越飞行非常火爆。相比其他类型的无人机,穿越机更依赖飞手的操纵技术来完成飞行,本属于模型的范畴,却偏偏被扣上了无人机的帽子。 相似文献
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我国优秀女子20km竞走运动员后半程竞走技术的三维运动学研究 总被引：1，自引：0，他引：1
运用三维录像解析法、数理统计法、对比分析法等方法对我国优秀女子20km竞走选手后半程竞走技术进行研究,以田径理论和生物力学知识为基础,对所得数据与世界优秀选手对比分析。结果得出：我国选手在身体重心上下位移、蹬伸角度及肩髋扭转角等参数方面,与世界优秀水平相比,均存在显著性差异。蹬伸用力效果差是造成这种技术表现的致因所在。 相似文献
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通过对９６’麦克杯全国武术锦标赛中的难度动作单腿前翻身的技术动作分析,提出了具体的辅助性训练及建议,为武术教学提供参考依据。 相似文献
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Dustin Bruening James G. Richards 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(2):215-225
An articulated boot design is commonly used in skiing and skating sports because it allows sagittal plane ankle mobility while still providing critical frontal plane stability. Although articulated boots have been in use for several decades, current manufacturers of these boots differ in their articulation placement. In this study we determined an optimal position of the ankle articulation axis. We also calculated the amount of anterior skin movement that a boot tongue must account for during a full range of ankle motion. Three‐dimensional kinematic data were collected and analyzed from 40 participants moving their right foot through a full range of sagittal plane motion. The calculated horizontal position of the articulation axis was found to be highly predictable from foot length (r = 0.87, standard error of estimate = 3.44 mm), while its vertical component displayed less predictability (r = 0.49, standard error of estimate = 7.46 mm). The expansion required by the boot tongue had a moderate association with foot length and low variability (r = 0.58, standard error of estimate = 0.07 mm). An accurate axis placement will minimize relative motion between the boot cuff and the ankle, reducing friction and motion resistance. An expandable tongue will accommodate full plantar flexion and reduce pressure on the anterior ankle during dorsiflexion, eliminating common pressure‐related injuries. 相似文献
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神经功能障碍是导致脑认知能力衰退和神经退行性疾病的重要原因,但其内在的诱导机制尚不清楚。随着学界对肠道微生物研究的深入,发现肠道微生物在许多机体疾病的发展中扮演重要角色,而神经功能障碍亦不例外。肠神经系统与中枢神经系统的信息通路使得肠道微生物与神经功能建立了肠-脑轴间的联络,肠道微生态的变化可通过肠-脑轴间的联络而影响神经功能。研究发现,规律的运动可通过影响肠道微生态进而改善神经功能,抑制神经系统疾病,但其内在调节机制亦不明确,这可能与运动介导肠道微生物多样性、肠道免疫、肠道内分泌、肠道代谢以及运动改善肠-脑间神经联系和神经发生等机制有关。 相似文献
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Turns (pirouettes) are an important movement in ballet and may be affected by “lateral bias”. This study investigated physiological differences exhibited by experienced and novice dancers, respectively, when performing pirouette with dominant and non-dominant leg supports, respectively. Thirteen novice and 13 experienced dancers performed turns on dominant or non-dominant legs. The maximum ankle plantarflexion, knee extension and hip extension were measured during the single-leg support phase. The inclination angle of rotation axis is the angle between instantaneous rotation axis and global vertical axis in the early single-leg support phase. Both groups exhibited a greater hip extension, knee extension, and ankle plantarflexion when performing a turn on the non-dominant leg. For experienced dancers, the inclination angle of rotation axis during the pre-swing phase was generally smaller for dominant leg support than non-dominant leg. However, no significant difference was found in inclination angle of rotation axis of novice dancers. For experienced dancers, an improved performance is obtained when using the dominant leg for support. By contrast, for novice dancers, the performance is independent of choice of support leg. The significant lateral bias in experienced dancers indicates the possible influence of training. That is, repetitive rehearsal on the preferred leg strengthens the impact of side dominance in experienced dancers. 相似文献
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This study examined the effects of equal anaerobic and aerobic total work outputs on the relationship between reproductive hormones in men. Nine subjects performed three randomized trials on separate days: (1) 1 h period of rest (control), (2) 1 h continuous aerobic exercise (65% VO2 max), and (3) 1 h intermittent anaerobic exercise (which included 2 min exercise periods at 110% FO2 max). The total work output of the aerobic and anaerobic trials were equated. For the 8 h after each experimental trial, blood samples were collected hourly and analysed for testosterone, luteinizing hormone (LH), follicle‐stimulating hormone (FSH), prolactin and cortisol. Diet, physical activity and circadian influences were all controlled. Compared with the control, the aerobic and anaerobic trials significantly (P < 0.05) elevated testosterone, prolactin and cortisol; however, these changes were transient and returned to control levels within 1–2 h of recovery. Neither exercise produced significant (P > 0.05) changes from control for LH and FSH. The area under the hormonal response curves (AUC) was calculated for the 8‐h recovery period. The testosterone and LH AUC results did not differ (P > 0.05) among the trials (the FSH AUC was not calculated). The prolactin AUC for the aerobic and anaerobic trials were greater (P < 0.01) than the control trial. The cortisol AUC for the anaerobic trial was greater than both the control and aerobic trials (P < 0.05), but the aerobic and control trials did not differ from one another. Correlation analysis among the AUC results within each trial showed testosterone and LH to be significantly related during the control (r = 0.723, P < 0.05) and aerobic (r = 0.801, P < 0.01) trials, but not so during the anaerobic trial (r = 0.430, P > 0.05). No other significant correlations were found. The present findings suggest the relationship between testosterone and LH is affected by anaerobic exercise but not aerobic exercise. However, the effect of anaerobic exercise upon the testosterone‐LH relationship did not seem related to the concurrently induced prolactin or cortisol changes. Anaerobic exercise may produce some degree of temporary alteration within the testosterone‐LH component of the hypothalamic‐pituitary‐gonadal axis; however, the mechanism for this phenomenon remains unclear. 相似文献
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运动应激对HPA轴的影响和适应 总被引：1，自引：0，他引：1
不同种类运动应激对HPA轴产生不同的影响,而机体的HPA轴也相应产生不同的适应性变化。这种变化主要体现在功能上,而且在HPA轴的各个环节都体现出来。作为反映HPG轴个环节功能的代表性指标CRH、ATCH和C有不同的变化趋势,并对其变化的机理进行了探讨。 相似文献
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不同种类运动应激对HPG轴下丘脑-垂体系统产生不同的影响,而机体的HPG轴下丘脑-垂体系统也产生不同的适应性变化,作为反映HPG轴下丘脑-垂体系统功能的代表性指标GnRH、LH和FSH有不同的变化趋势。本文对其变化的趋势及机理进行了探讨。 相似文献
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把突出"第三个轴"的"四轴理论"运用到铁饼教学中,并采用技术重点组合教学法进行教学,取得了很好的教学效果,为提高铁饼的教学质量提供了参考. 相似文献