气门锻坯盘部端面“环形圈”缺陷理论分析

一、引 言 产品质量很大程度上取决于锻坯质量,提高锻坯质量对于提高产品质量至关重要。 本厂的气门锻坯质量长期不够稳定,除了一些其它类型的缺陷以外,其中盘部端面上产生“环形圈”（实际是环形折叠纹）是一种常见缺陷。由于“环形圈”是以折叠的外形出现,其深度常常不易判断和检测。要想了解缺陷的深度,必须通过破坏性纵向剖切后观察。“环形圈”深度若超过机加工尺寸余量（本厂气门端面机加工余量一般定在1～1.5mm）,机加工后的成品就会因不符合图纸要求而报废,即造成原材料、工时等方面的浪费。 为了避免或减少上述浪费,对气门锻坯“环形圈”缺陷产生的原因、过程等进行理论分析,从而达到锻坯质量的早期判定,甚至彻底避免该缺陷的产生,无疑是具有一定意义和价值的。 本文试图从气门锻坯的电镦加热,锻造成形中与质量有关的一系列因素的影响入手,通过对锻坯的整个变形形式、过程及其应力状态进行理论分析,判明“环形圈”产生的原因和过程,以便找出预防该缺陷的途径。

提高气门盘部凹坑对杆部同轴度的措施

对气门毛坯锻压机原模具定位机构进行考察分析,针对其结构和受力机构不合理等诸多问题,提出改进设计方案,通过试验得知,新的模具定位机构既能有效地改善气门盘部凹坑相对杆部的同轴度,又能降低其工艺成本.本文介绍的内容对盘部有凹坑的气门生产厂家具有广泛的适用价值,对盘部平端面的气门生产亦具借鉴作用.

气门热处理校直方法的几次改进与效果分析

针对气门热处理与抛丸后的超差变形,分析了气门校直方法的改进过程,指出了校直机结构与在不同发展时期的应用情况,同时介绍了校直机的优缺点,并提出了气门校直机的发展趋势。

提高高颈法兰液态模锻质量的方法

研究了高颈法兰的一种成形技术.针对薄壁高颈法兰零件,设计了一种特殊的液态模锻技术,通过对颈部与盘部实施不同的压缩量,解决了高颈法兰普通液态模锻中颈部与盘部致密度不一致而引起性能不均匀的问题.实验结果表明,该技术可以提高法兰颈部的组织和力学性能,消除短板效应,提高高颈法兰的整体质量.

Performance Optimization of Torque Converters Based on Modified 1D Flow Model

A methodology for performance optimization of torque converters is put forward based on the one-dimensional (1D) flow model. It is found that the inaccuracy of 1D flow model for predicting hydraulic performance at the low speed ratio is mainly caused by the separation phenomenon at the stator cascade which is induced by large flow impinging at the pressure side of the stator blades. A semi-empirical separation model is presented and incorporated to the original 1D flow model. It is illustrated that the improved model is able to predict the circumferential velocity components accurately, which can be applied to performance optimization. Then, the Pareto front is obtained by using the genetic algorithm (GA) in order to inspect the coupled relationship among stalling impeller torque capacity, stalling torque ratio and efficiency. The efficiency is maximized on the premise that a target stalling impeller torque capacity and torque ratio are achieved. Finally, the optimized result is verified by the computational fluid dynamics(CFD) simulation, which indicates that the maximal efficiency is increased by 0.96%.

Applications and research in frame longeron of hydroforming

The application feasibility of hydroforming in frame longeron large parts is verified for the first time at home. The result of the research on the structure design and process analysis for frame longeron shows that hydroforming can he fully realized. With stiffness is comparison, collision test simulation and cross section force with traditional drawing- assembly welding techniques, it has been found that hydroforming combining has multiple advantages such as light- weight, high stiffness, reduction in the number of parts, high precision, hence reduction the associated machining and welding and so on. It is especially suitable for forming various lightweight components used for the chassis parts in automotive.

Treatment of Protrusion of the Lumbar Intervertebral Disc by TCM Massage

Protrusion of the lumbar intervertebral disc is a common disorder frequently encountered in clinic. With TCM massage and the maneuver of manual reduction, we have treated 82 cases of protrusion of the lumbar intervertebral disc, with satisfactory therapeutic results reported in the following.……

CASTLEMAN＇S DISEASE OF THE ABDOMINAL REGION IN ADOLESCENT

Objective To describe the CT features of abdominal Castleman's disease(CD)in adolescent.Methods Abdomen CT of four adolescents ranging in age from 7 years to 17 years diagnosed as abdominal region CD were reviewed.One case was retroperitoneal CD;one case was lesser omentum CD;and the other two cases were mesenteric CD.Three of four cases underwent post enhancement,and one case was only done no contrast CT as the reason of media hypersusceptibility.One case underwent needle biopsy.Three cases were removed by surgical resection.Results Isolated or multiple well-defined homogenous masses with homogenously enhanced after underwent enhancement was the common finding in these four cases.Conclusion Recognition of the CT features and highlights the histological specimen of CD is helpful to diagnose CD.

Data Recovery Based on Intelligent Pattern Matching

To solve the problem of data recovery on free disk sectors, an approach of data recovering based on intelligent pattern matching is proposed in this paper. Different from the methods based on the file directory, this approach utilizes the consistency among the data on the disk. A feature pattern library is established based on different types of fries according to the internal constructions of text. Data on sectors will be classified automatically by data clustering and evaluating. When the conflict happens on data classification, the digestion will be initiated by adopting context pattern. Based on this approach, the paper achieved the data recovery system aiming at pattern matching of txt, word and PDF fries. Raw and formatting recovery tests proved that the system works well.

Technique for calibration of chassis components based on encoding marks and machine vision metrology

A novel technique for calibrating crucial parameters of chassis components is proposed,which utilizes the machine vision metrology to measure 3D coordinates of the center of a component's hole for assembling in the 3D world coordinate system.In the measurement,encoding marks with special patterns will be assembled on the chassis component associated with cross drone and staff gauge located near the chassis.The geometry and coordinates of the cross drone consist of two planes orthogonal to each other and the staff gauge is in 3D space with high precision.A few images are taken by a highresolution camera in different orientations and perspectives.The 3D coordinates of 5 key points on the encoding marks will be calculated by the machine vision technique and those of the center of the holes to be calibrated will be calculated by the deduced algorithm in this paper.Experimental results show that the algorithm and the technique can satisfy the precision requirement when the components are assembled,and the average measurement precision provided by the algorithm is 0.0174 mm.

Clinical Observation on Acupoint Sticking Therapy for Lumbar Intervertebral Disc Hernination

Objective： To observe the clinical effects of acupoint sticking therapy for umbar intervertebral disc herniation. Methods： Seventy patients with lumbar intervertebral disc herniation were randomly divided into two groups by the visit order, 35 cases in each group. The treatment group was treated with acupoint sticking therapy and the control group was treated with tuina. After treatment, the clinical effects, pain integral and Japanese Orthopedic Association （JOA） scores were compared between the two groups. Results： The total effective rate, pain integral and improvement of JOA scores were better in the treatment group than in the control group （P〈O.O5）. Conclusion： Acupoint sticking therapy is affirmative in the therapeutic effects and better than tuina treatment for lumbar intervertebral disc herniation.

Observation on therapeutic effect of acupuncture at abdomen acupoints plus tuina for lumbar intervertebral disc herniation

Objective: To observe the clinical efficacy of acupuncture at abdomen acupoints plus tuina for lumbar intervertebral disc herniation (LIDH). Methods: A total of 70 patients with LIDH were randomized into an observation group and a control group, with 35 cases in each group. The observation group was treated with acupuncture at abdomen acupoints plus tuina, while the control group was treated only with tuina treatment. The clinical efficacy was observed after one course of treatment. Results: The cure rate and the total effective rate of the observation group were 83.3% and 96.7%, respectively. The cure rate and the total effective rate of the control group were 39.4% and 78.8%, respectively. There were significant differences in the cured rate and the total effective rate between the two groups (both P<0.05). There was no significant differenee in Japanese Orthopedic Association (JOA) score between the two groups before treatment (P>0.05). After treatment, the JOA scores of both groups in creased sign ifica ntly, and the in tra-group differe nces were statistically sign ifica nt (both P<0.05);the JOA score of the observation group was significantly higher than that of the control group (P<0.05). Conclusion: Acupuncture at abdomen acupoints plus tuina has a better therapeutic effect than tuina alone in the treatment of LIDH.

Nocturnal polyuria after lumbar disc herniation surgery

A male patient with seventy-six years old, frequent urination at night, lassitude, aversion to cold, feeling tired easily on exertion, soreness and weakness in the lumbar region, dark and purplish tongue with white coating, deep, thread and rapid pulse. Diagnosis: nocturnal polyuria. Syndrome differentiation in traditional Chinese medicine: kidney yang deficiency. In treatment, the Du-moxibustion(moxibustion along the Governor vessel) was adopted in the lumbosacral region. A number of cross marks were marked along Zhōngshū(中枢GV 7) to Yaoshù(腰俞 GV 2). Herbal powder for the Du-moxibustion was put evenly and straightly from GV 7 to GV 2 along the cross marks. The mulberry bark paper was put flatly over the treating region with the folded midline of the paper matching the powder line and the ginger paste was placed on the paper and flatted with the tongue depressor as a trapezium. A groove was pressed on the ginger paste, And moxa was put inside. The upper, middle and lower sites of the moxa were ignited for moxibustion,when the moxa was burnt out then new moxa was replaced. Totally,the moxa was changed 3 times in one treatment. The treatment was given once a week, and 4 treatments as one course. After 2-course Du-moxibustion, the frequency of nocturnal urination was 0-1 time,0-350 mL a night. The patient had lassitude and fatigue occasionally and had no aversion to cold. The treatment was given once every two weeks on the lumbosacral region until the urine frequency was normal at night. The Du-moxibustion improves in kidney yang deficiency, kidney qi deficiency, post-operative body weakness and the deficiency cold of the lower Jiao. This therapy warms the meridian, promotes qi and blood circulation, shortens the recovery time of the normal circulation of the cerebrospinal fluid and nourishes cauda equina as well as alleviates the pressure to cauda equina due to edema. This therapy effectively treats nocturnal polyuria of kidney yang deficiency after lumbar disc herniation surgery.

Piecewise model and experiment of power chuck's gripping force loss during high speed turning

High speed power chucks are important function units in high speed turning.The gripping force loss is the primary factor limiting the rotational speed of high-speed power chucks.This paper proposes a piecewise model considering the difference of wedge transmission's radial deformation between low-speed stage and medium-to-high-speed stage,the friction forces of chuck transmission,and the compressibility of hydraulic oil in rotary hydraulic cylinders.A corrected model of gripping force loss is also established for power chucks with asymmetric stiffness.The model is verified by experiment results.It is helpful to use the piecewise model to explain the experimental phenomenon that the overall loss coefficient of gripping force increases with the rotational speed increasing at medium and high speed stages.Besides,the loss coefficients of gripping force at each stage during speeding up and the critical rotational speed between two adjacent stages are discussed.For wedge power chucks with small wedge angel(α<20°) and ordinary lubrication(μ0>0.06),the local loss coefficient of gripping force at the low speed stage is about 70% of that at the medium to high speed stage.For wedge power chucks with larger wedge angel(α>20°) or low friction coefficient(μ0<0.06),the wedge transmissions cannot self-lock at high speed stage,and the gripping force loss at the high speed stage is related to the hydraulic lock and hydraulic oil in the rotary hydraulic cylinder;the local loss coefficients of gripping force at the third stage is about 1.75 to 2.13 times that at the second stage.This work is helpful to understand the mechanism of the gripping force loss thoroughly and to optimize power chucks.