Study of Two-Stage Tightening of Threaded Fasteners Using Various Tool Speed Combinations

2007 ◽  
Author(s):  
Saravanan Ganeshmurthy ◽  
Sayed A. Nassar
Keyword(s):  
Automotive Industry ◽  
Mass Production ◽  
Control Process ◽  
High Volume ◽  
Torque Control ◽  
Bolted Joints ◽  
Two Stage ◽  
Tightening Torque ◽  
Threaded Fasteners ◽  
Bearing Friction

This paper investigates the effect of various tool speed combinations on the torque-tension relationship in a two-stage torque control process for the tightening of threaded fasteners. The tightening speed has a considerable affect on the thread and bearing friction coefficients. Hence, the amount of clamp load generated by a specified level of the tightening torque is significantly influenced by the tool speed combinations in many high volume applications. In two-stage processes, the fastener is first tightened to an intermediate torque level beyond which the tool speed is changed but the tightening is continued until the full target torque is reached. The effect of tightening speed combinations (for stages one and two) on the torque-tension relationship is investigated. Data on the coefficients of thread and bearing friction as well as the Nut Factor K is investigated. The findings of this study are helpful in predicting the clamp load generated in bolted joints, which enhance its reliability and safety. Additionally, the study provides helpful data that may be utilized for developing reliable assembly strategies in mass production applications such as the automotive industry.

Improvement of Tightening Accuracy of Torque Control Method by Taking Account Geometric Errors in Threaded Fasteners

2016 ◽  
Author(s):  
Toshimichi Fukuoka ◽  
Keisuke Nakano
Keyword(s):  
Control Method ◽  
Primary Source ◽  
Torque Control ◽  
Bolted Joints ◽  
Large Scatter ◽  
Bearing Surface ◽  
Threaded Fasteners ◽  
Bolt Preload ◽  
Essential Problem ◽  
Easy Operation

Torque control method is commonly used when tightening bolted joints because of its easy operation. However, the method involves an essential problem of fairly large scatter in bolt preloads. It has been reported that even if the same torque is applied, bolt preloads show a considerable scatter, e.g., ranging from 25% to 35%. A scatter in coefficients of friction on nut bearing surface and thread pressure flank is a primary source of bolt preload scatter. Meanwhile, the effect of Equivalent Friction Diameter at the bearing surfaces of nut and bolt head cannot be ignored. The scatter in Equivalent Friction Diameter is caused by imperfect geometry, i.e., the flatness deviation at the bearing surfaces. In this paper, the magnitudes of Equivalent Friction Diameter are quantitatively evaluated by FEA, using the experimental data of flatness deviation measured for a number of commercial nuts and bolts. It is shown that the bolt preload is likely to be scattered by as much as plus minus 10% of the target value, owing to the flatness deviation. Based on the comprehensive calculations by considering the imperfect geometry, a strategy to effectively suppress the bolt preload scatter is proposed.

Improved Roller Hemming System for High Volume Part Production

2011 ◽  
Vol 473 ◽  
pp. 168-175 ◽  
Author(s):  
Martin Zubeil ◽  
Karl Roll ◽  
Marion Merklein
Keyword(s):  
Strain Rate ◽  
Surface Quality ◽  
Automotive Industry ◽  
Dimensional Stability ◽  
Cycle Time ◽  
High Volume ◽  
Non Linear ◽  
Part Production

Roller hemming is usually applied for hang-on-parts such as hoods, doors or trunk-lids which all have complex non-linear geometries. The flange is often hemmed along both surfaces and edges which have 3D curvilinear shapes. Minimization of hemming defects and the requirement to improve cycle time of the roller hemming process are essential for roller hemmed hang-on-parts in the automotive industry. Different systems such as the driven roller hemming provide the possibility to increase the strain rate without loosing surface quality and dimensional stability. Investigating the influence of friction during roller hemming, results will give an understanding of the advantage for mentioned roller hemming systems.

Optimization of Novel Corner Module for Urban Electric Vehicle

2017 ◽  
Author(s):  
Allison J. Waters ◽  
Amir Khajepour
Keyword(s):  
Automotive Industry ◽  
Public Transportation ◽  
Mass Production ◽  
Ride Comfort ◽  
Lateral Displacement ◽  
Traffic Density ◽  
Ride Height ◽  
Short Supply ◽  
Module Design ◽  
Camber Angle

With urban populations on the rise, sustainable design of cities will be necessary to maintain reasonable quality of life for its inhabitants. Space to accommodate citizens in these densely populated cities will be in short supply and high demand. Strategic shifts in the transportation industry can alleviate the lack of space for residential and commercial facilities in densely populated areas. One opportunity to mitigate this growing problem is to reduce the size of personally owned, commuter vehicles. Smaller vehicles will reduce the storage space and increase the density of vehicles on roads. Another solution gaining traction in the automotive industry today are autonomous vehicles. Autonomous technology can allow cars to travels closer to one another without increasing the likelihood of a crash. Lastly, changing the market from personally owned vehicles to fleets owned by the company to be used as public transportation would reduce the traffic density. These changes to the automotive industry will facilitate a change in the layout and packaging of commercial vehicles to meet new objectives. This paper proposes a novel corner module design that meets the market’s needs for mass production of X-by-wire systems integrated into a compact space while maintaining current levels of vehicle stability, handling and ride comfort. The proposed corner module features an in-wheel motor with electronic steering and braking. To increase the handling of the vehicle, the corner module has active camber control and can be modified for active ride height adjustment. Furthermore, the simplicity and minimal quantity of the components makes the corner module design ready for mass production. The geometry of the purposed corner module was optimized using a genetic algorithm. The objectives were to target a wheel lateral displacement of 10 cm at the −15° of camber angle and to minimize the longitudinal displacement of the wheel in a steer range of −20° to 20° at 0° of camber angle. The optimization had three types of constraints: packaging space limits, component interference and cylinder size. The optimization successfully found a solution that met both objectives while remaining within the constraints. The workspace of the wheel was limited by the rear cylinder size and the fixed length of the linkage.

scholarly journals A Two-Stage Quality Control Method for 2-m Temperature Observations Using Biweight Means and a Progressive EOF Analysis

2013 ◽  
Vol 141 (2) ◽  
pp. 798-808 ◽  
Author(s):  
Zhifang Xu ◽  
Yi Wang ◽  
Guangzhou Fan
Keyword(s):  
Quality Control ◽  
Control Method ◽  
Control Process ◽  
Lapse Rate ◽  
Systematic Bias ◽  
Eof Analysis ◽  
Two Stage ◽  
Quality Control Method ◽  
Quality Control Process ◽  
The Difference

Abstract The relatively smooth terrain embedded in the numerical model creates an elevation difference against the actual terrain, which in turn makes the quality control of 2-m temperature difficult when forecast or analysis fields are utilized in the process. In this paper, a two-stage quality control method is proposed to address the quality control of 2-m temperature, using biweight means and a progressive EOF analysis. The study is made to improve the quality control of the observed 2-m temperature collected by China and its neighboring areas, based on the 6-h T639 analysis from December 2009 to February 2010. Results show that the proposed two-stage quality control method can secure the needed quality control better, compared with a regular EOF quality control process. The new method is, in particular, able to remove the data that are dotted with consecutive errors but showing small fluctuations. Meanwhile, compared with the lapse rate of temperature method, the biweight mean method is able to remove the systematic bias generated by the model. It turns out that such methods make the distributions of observation increments (the difference between observation and background) more Gaussian-like, which ensures the data quality after the quality control.

Zerspanprozesse effizienter machen*/Making machining process more efficent - Recording and analysis of non-productive times in the automotive industry

2015 ◽  
Vol 105 (05) ◽  
pp. 301-306
Author(s):  
T. Bosch ◽  
W. Polley ◽  
S. Schöll ◽  
P. Klemm
Keyword(s):  
Automotive Industry ◽  
Mass Production ◽  
Machining Process ◽  
Sich Eine ◽  
Analysis Method ◽  
Negative Effects ◽  
Advantages And Disadvantages ◽  
Production Processes

Dieser Fachartikel geht auf die negativen Auswirkungen technischer Nebenzeiten für die Effizienz von Produktionsprozessen in der automobilen Großserienproduktion ein. Er zeigt in der Übersicht, welche Methoden sich zur Erfassung technischer Nebenzeiten eignen und welche Vor- und Nachteile sie besitzen. Nur mit diesen Erfassungsmethoden lässt sich eine effektive Minimierung von technischen Nebenzeiten erreichen. Anschließend wird ein dreistufiges Analyseverfahren präsentiert.   This article discusses the negative effects of non-productive times on the efficiency of production processes in automotive mass production. An overview shows which methods are suitable for the recording of non-productive times and their advantages and disadvantages. These recording methods are essential for the effective minimization of non-productive times. Subsequently, an analysis method, which is composed of three steps, is presented.

Viscous Friction Effect During the Process of Tightening and Loosening of Bolted Joints

2021 ◽  
Author(s):  
Qingyuan Lin ◽  
Yong Zhao ◽  
Qingchao Sun ◽  
Kunyong Chen
Keyword(s):  
Friction Coefficient ◽  
Viscous Friction ◽  
Normal Pressure ◽  
Friction Model ◽  
Bolted Joints ◽  
Critical Parameters ◽  
Bolted Joint ◽  
Sliding Velocity ◽  
Friction Effect ◽  
Bearing Friction

Abstract Bolted connection is one of the most widely used mechanical connections because of its easiness of installation and disassembly. Research of bolted joints mainly focuses on two aspects: high precision tightening and improvement of anti-loosening performance. The under-head bearing friction coefficient and the thread friction coefficient are the two most important parameters that affect the tightening result of the bolted joint. They are also the most critical parameters that affect the anti-loosening performance of the bolted joint. Coulomb friction model is a commonly used model to describe under-head bearing friction and thread friction, which considers the friction coefficient as a constant independent of normal pressure and relative sliding velocity. In this paper, the viscous effect of the under-head bearing friction and thread friction is observed by measuring the friction coefficient of bolted joints. The value of the friction coefficient increases with the increase of the relative sliding velocity and the decrease of the normal pressure. It is found that the Coulomb viscous friction model can better describe the friction coefficient of bolted joints. Taking into account the dense friction effect, the loosening prediction model of bolted joints is modified. The experimental results show that the Coulomb viscous friction model can better describe the under-head bearing friction coefficient and thread friction coefficient. The model considering the dense effect can more accurately predict the loosening characteristics of bolted joints.

Effect of washer size and tightening torque on the performance of bolted joints in composite structures

2006 ◽  
Vol 73 (3) ◽  
pp. 310-317 ◽  
Author(s):  
U.A. Khashaba ◽  
H.E.M. Sallam ◽  
A.E. Al-Shorbagy ◽  
M.A. Seif
Keyword(s):  
Composite Structures ◽  
Bolted Joints ◽  
Tightening Torque

Dynamic Characteristics of Plastic Plates With Bolted Joints

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Akira Saito ◽  
Hideyoshi Suzuki
Keyword(s):  
Dynamic Characteristics ◽  
Vibration Mode ◽  
Acrylonitrile Butadiene Styrene ◽  
Bolted Joints ◽  
Modal Testing ◽  
Analytical Models ◽  
Plate Motion ◽  
Tightening Torque ◽  
Modeling Strategy ◽  
Torque Values

Abstract This paper discusses the dynamic characteristics of plastic plates with bolted joints. The effects of tightening torque on the modal properties of the plates are investigated. Experimental and numerical modal analyses have been conducted on the plates made of acrylonitrile butadiene styrene (ABS), that are clamped by bolted joints. First, the effect of tightening torque on the vibration mode of the plates is investigated by experimental modal analyses. Modal testing has been conducted for various tightening torque values, and the relationships between the modal parameters and the tightening torques are discussed. Second, the effects of tightening torque on the vibration mode are studied by using analytical models for the bolted joints based on the finite element method (FEM). Based on the comparisons between the experimental and the numerical results, a modeling strategy for the boundary conditions between the plates is introduced and its validity is discussed. From both experimental and numerical studies, it is shown that the natural frequencies of the structures with bolted joints tend to converge to specific values as tightening torque increases. Moreover, it is also shown that when modeling the bolted plates by FEM, the inter-plate motion should be constrained by a boundary condition to properly suppress the out-of-phase motion of the plates.

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