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关键词： 设计思路   离合器   实现方法  

摘要： 随着生活品质提升,汽车使用量增多,汽车离合器作为功能显著的汽车配件,其性能不容忽视,离合器地位特殊,是传动系统重要成员。在实际应用中,离合器对汽车起步的稳定性作用较大,如果离合器性能不达标,出现不平稳的情况,熄火现象将会发生,影响行车体验。对此,文章将研究离合器的设计理念以及实现方法,以便为离合器性能优化提供参考。

关键词： 玉米收获机   摩擦片式离合器   故障现象   解决措施  

摘要： 列出了收割机摩擦片式离合器产品质量问题的常见故障现象;针对故障原因进行了分析;并相应提出改进措施。

关键词： wet clutch   friction heat   friction torque   friction power  

摘要： The effect of the design parameter on the clutch engagement process of the hydro-mechanical continuously variable transmission(CVT)was ***,the model of the power train was developed with the software of SimulationX,and the clutch shift experiment was used to validate the correctness of the ***,the friction coefficient function was fitted with the test data to get the friction coefficient model suitable for this ***,based on the evaluating index of the friction torque and the friction power,two groups of design parameters(oil pressure and friction coefficient)were simulated and explained the changing regulation *** to the simulation results,the high oil pressure and friction coefficient can reduce the slipping *** large oil pressure can increase the peak torque but the effect of friction coefficient on the peak torque is not so *** friction power reaches the maximum value at 3.2 s,the peak value increases as the oil pressure and friction coefficient *** effect of the oil pressure on the clutch engagement and thermal performance is greater than the friction coefficient.

关键词： 柴油发动机   四轮驱动   四驱系统   分动器   故障码   离合器   行驶里程   VIN  

摘要： 车型:2018年长城风骏5皮卡,配置4D20D国五柴油发动机、6速手动交速器。VIN:LGWDBE198JB××××××。行驶里程:23000km。故障现象:一辆2018年长城风骏5皮卡,搭载博格华纳电控四驱系统,按下四驱开关4H或4L后,车辆都无法实现四轮驱动,四驱系统报“P173467前桥离合器反馈错误”故障码。故障诊断:举升车辆,启动着车后,踩下离合器,按下4H或4L开关,挂挡行驶,只有两个后轮转动,分动器换挡电机能够动作,但前桥离合器电机不动作,两个前轮不转。

关键词： 离合器接合控制   动力学模型   NSGA-Ⅱ算法   冲击程度   滑动摩擦功   正态分布交叉   自适应变异   平稳性和耐用性  

摘要： 为了提高车辆在起步过程中的平稳性,并延长离合器的使用寿命,首先,根据离合器的主动盘和从动盘的运动状态,建立了接合过程的动力学模型;然后,通过引入NSGA-Ⅱ算法来解决多目标优化问题,并采取了正态分布交叉和自适应变异算子对其进行改进,保持了种群的多样性,能有效防止陷入局部最优;最后,将离合器的接合时长和接合速度作为设计变量,并将冲击程度和滑动摩擦功为优化目标函数进行了仿真实验。结果表明,改进的NSGA-Ⅱ算法具有更优的Pareto前沿和更快的收敛速度,且分布更加均匀,明显优于其他两种比较算法;在相同接合时长的条件下,能够通过平稳控制离合器的接合速度获得更小的冲击程度和滑动摩擦,为设计离合器接合控制策略提供了技术支撑。

关键词： Lupus   calprotectin   imiquimod   gut permeability   mice   TLR  

摘要： Background Intestinal and hepatic manifestations of lupus seem to be underestimated in comparison to other major organ lesions. Although recent data point to gut-liver axis involvement in lupus, gut permeability dysfunction and liver inflammation need to be more investigated. Objective This study aims to assess fecal calprotectin, intestinal tight junction proteins and liver inflammation pathway in wild-type murine imiquimod- induced lupus. Methods C57BL/6 mice were topically treated on their right ears with 1.25 mg of 5% imiquimod cream, three times per week for six weeks. Fecal calprotectin was collected at day 0, 22 and 45. Renal, liver and intestinal pathology, as well as inflammatory markers, intestinal tight junction proteins, and E. coli protein in liver were assessed at sacrifice. Results At six weeks, lupus nephritis was confirmed on histopathology and NGAL and KIM-1 expression. Calprotectin rise started at day 22 and persists at day 45. Protein expression of Claudine, ZO-1 and occludin was significantly decreased. E. coli protein was significantly increased in liver with necro-inflammation and increased TLR4, TLR7, and pNF kappa B/NF kappa B liver expression. Conclusion This study is the first to demonstrate early fecal calprotectin increase and liver activation of TLR4- NF kappa B pathway in wild-type murine imiquimod-induced lupus.

关键词： Magnetorheological fluids   clutch   actuator   optical sensor   condition monitoring  

摘要： The aerospace industry is gradually moving toward "more electric aircraft" to reduce its environmental footprint. Developing all-electric actuators brings a reliability challenge because conventional geared-motor actuators are susceptible to jamming failures from their metal-to-metal gear contacts. Magnetorheological clutch actuators solve this challenge using a layer of fluid to transmit torque and are not exposed to potential jam failures, making them particularly attractive for high reliability applications such as primary flight controls. A key challenge that must be addressed for a widespread deployment of the magnetorheological fluid technology in aerospace is the ability to monitor magnetorheological fluid condition while it degrades in operation. To date, no such efforts have been reported in the literature. Recent studies on magnetorheological fluid durability have shown that mixing the magnetorheological fluid using a magnetic screw pump principle can significantly increase the life of the fluid by up to 50%. This article presents the design, prototyping, and testing of a proof-of-concept magnetorheological fluid condition monitoring sensor, capitalizing on the flow-recirculating properties of magnetic screw magnetorheological clutches to continuously provide a well-mixed and homogeneous fluid sample to the sensor. The proposed sensing principle uses optical red green blue sensor placed in the fluid circulation path to measure the fluid color during degradation. The sensor has been tested up to fluid failure on a high-torque (60 N m) magnetorheological clutch mounted on a fully instrumented durability test bench. Tests have been performed with two types of fluid: a commercially available fluid, the Lord 140CG, and a homemade fluid based on perfluoropolyether oil, the GPL-103. Results with the Lord fluid demonstrate a strong correlation between the decrease in torque-to-current performance with fluid brightness. The average of three aging tests on Lord 140C

关键词： axial spondyloarthritis   PCSK9   dyslipidaemia  

摘要： Objective. Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a serine protease that regulates cholesterol metabolism and has been linked to cardiovascular (CV) risk. The purpose of the present study was to examine whether PCSK9 levels are related to abnormalities in the lipid profile and the development of atherosclerosis that occurs in patients with axial SpA (axSpA). Methods. We performed a cross-sectional study that encompassed 545 individuals;299 patients with axSpA and 246 statin use-matched controls. PCSK9 and standard lipid profiles were analysed in patients and controls. Carotid intima-media thickness (cIMT) and carotid plaques were assessed in patients. A multivariable analysis, adjusted for standard CV risk factors, was performed to evaluate the influence of PCSK9 on axSpA-related dyslipidaemia and subclinical carotid atherosclerosis. Results. Total cholesterol, high-density lipoprotein and low density lipoprotein cholesterol, lipoprotein (a) and apolipoprotein A1 were significantly lower in axSpA patients than controls. PCSK9 serum levels [beta coefficient -44 ng/dl (95% CI -60, -27), P=0.000] were also downregulated in axSpA patients after fully multivariable adjustment. ASDAS-CRP was found to be independently and significantly related to PCSK9 [beta coefficient 10 ng/dl (95% CI 1, 18), P=0.023] after analysing fully adjusted models that took age, sex and the rest of the lipid profile molecules into account. Whereas patients taking prednisone showed higher serum levels of PCSK9 [55 ng/ml (95% CI 24, 8), P=0.001], those under anti-TNF-alpha therapies exhibited lower levels [beta coefficient -26 ng/ml (95% CI -43, -9], P=0.003]. Conclusion. PCSK9 is downregulated in patients with axSpA. Disease activity is positive and significantly related to PSCK9. Anti-TNF-therapy yields a reduction in PCSK9 serum levels.

关键词： Automotive   active suspension   magnetorheological clutches   controlled slippage actuator   rack   and pinion mechanism  

摘要： The main functions of automotive suspensions are to improve passenger comfort as well as vehicle dynamic performance. Simultaneously satisfying these functions is not possible because they require opposing suspension adjustments. This fundamental design trade-off can be solved with an active suspension system providing real-time modifications of the suspension behavior and vehicle attitude corrections. However, current active suspension actuator technologies have yet to reach a wide-spread commercial adoption due to excessive costs and performance limitations. This paper presents a design study assessing the potential of magnetorheological clutch actuators for automotive active suspension applications. An experimentally validated dynamic model is used to derive meaningful design requirements. An actuator design is proposed and built using a motor to feed counter-rotating MR clutches to provide upward and downward forces. Experimental characterization shows that all intended design requirements are met, and that the actuator can output a peak force of +/- 5300 N, a peak linear speed of +/- 1.9 m/s and a blocked-output force bandwidth of 92 Hz. When compared to other relevant technologies, the MR approach simultaneously shows both better force density and speeds (bandwidth) while adding minimal costs and weight. Results from this experimental assessment suggest that MR slippage actuation is promising for automotive active suspensions.

关键词： Anode-discharging mode   axial magnetic field (AMF)   opening velocity   vacuum circuit breaker (VCB)  

摘要： This article extends the quantitative method of optimizing the opening velocities for a vacuum circuit breaker (VCB) with cup-type axial magnetic field (AMF) contacts. The material of the AMF contact is Cu50Cr50. We define v(1) as the initial opening velocity over half the full contact gap and v(2) as the average velocity over the full contact gap of 20 mm. We optimize v(1) and v(2) using the transition of anode-discharging modes, of which we combine the footpoint mode and anode spot mode into a large-gap high-current (LGHC) mode. The experiment shows that v(1) should be higher than a threshold velocity v(1_th), which corresponds to a peak critical contact gap d(1_ th) for the transitions of an intense arc mode into a diffuse arc mode, in high-current interruption. The higher v(1) is than v(1_th), the faster the intense arc mode evolves into the diffuse arc mode. This helps successfully interrupt the short-circuit current in a short arcing time. Another threshold velocity, v(2_th), corresponds to the maximum critical contact d(II_ th) for the formation of an LGHC mode in the second arc current half-wave. A high v(1) design needs v(2) to be lower than v(2_th). The lower v(2) is than v(2_th), the better the VCB avoids the LGHC mode in high-current interruption. This helps interruption over a long arcing time. We propose an intelligent opening and breaking operation for VCBs with cup-type AMF contacts, whereby the VCB opens with different opening velocities according to the short-circuit current level.