Torque fasteners

The fastening torque of the mounting bolts of the integral power steering gear assembly is 90 ION m-... 

The fastening torque of the connecting bolts of the steering drive assembly and the left horizontal beam of the frame is 70 lON.m. 

Low creep—fastener torque remains high over the life of the part... 

Only high tensile (HT) fasteners must be used for busbar Jointing and their interconnections or links not only to take care of the fault level but to also maintain the recommended contact pressure over a long period of operation as noted in Table 29.1. An ordinary fastener may not be able to withstand or sustain this torque for long. Similarly, the busbar supports, which are mounted on only two or three fasteners, should also be fitted with these fasteners. 

The contact resistance can be minimized by increasing the pull of the fasteners. Increasing the area of overlap may not reduce the contact resistance, unless the number of fasteners is also increased. It is mandatory to maintain a certain minimum contact pres.stire per unit area of the joint overlap. An average contact pressure at around 40-55 kg/cm is considered adequate. For the purpose of easy application, it is expressed in terms of bolt torque, depending upon the area of overlap and the number of fasteners, as specified in Table 29.1. 

Use a torque wrench to tighten the fasteners to ensure correct surface-to-surface contact of the current-carrying parts (Figure 29.2(c)). The recommended values of bolt torque are given in Table 29.1. A pressure that is too high may eause relaxation of the joint by cold flow and must be avoided. 

Figure 29.2(c) Use of manual torque wrench to tighten the fasteners (motorised spanners are employed for faster production)... 

Recommended practices buses and making bus joints 29/907 Table 29.1 Recommended busbar overlaps for different sizes and torques of fasteners... 

These torque values w 11 normally require high tensile fasteners. ... 

An approximate relationship is eommonly used to determine the torque for assembly, M, for a given pre-load, FfShigley and Misehke, 1996). It is a standard formulation for bolts and fasteners determined from experiment and is related to the frietion found in the eontaeting surfaees of the parts on assembly. 

Second, having high assembly torque to prevent vibrational loosening is frequently ineffective, since creep in the plastic will reduce the effective assembly torque even if the fastener does not rotate. Using vibra-tionproof screws, lockwashers, locknuts, and thread-locking adhesives are usually a better alternative when loosening is considered a problem. 

The stirrer must provide good circulation if the temperature of th thermostat liquid is to be uniform. One design which is quite efficient and which occupies relatively little space is shown in Fig. 5-27. It is made from a length of brass tube to which supports have been silver-soldered at the top and bottom. A number of holes are drilled in the sides of the tube, and a central rod is fastened to the assembly. As this is turned (usually at — 1,500 to 1,800 rpm), centrifugal force throws the water out of the holes on the side. The supply of water is replenished through the top and bottom holes. The stirrer requires considerable torque for its operations, and it is usually necessary to employ at least a i/oo-hp motor. 

Mechanical Engineer Fastener identified Weight/tolerances Resistance to abrasion Vibration requirements (x, y, z) Form factor/extemal dimensions — tolerance study Terminal type Torque requirements for connections requirements and analysis Leakage Test Case material... 

The results for contact resistance were measured comparing the glass epoxy fabricated separators to the ceramic fabricated separators. These materials were fastened with 6 MIO screws under increasing torque conditions. Figure 6-6 compares the results between each material under the increasing torque and plots the resistances observed. The contact resistances measured are for one cell under torque and include the GDL resistance. This test shows that the ceramic separator resistance is much lower than that of glass epoxy. The measured resistance for the ceramic was 77% to that of the glass epoxy separator. 

The International Organization for Standardization (ISO) has finalized an International Standard (ISO/DIS 10964 1993) Adhesives Anaerobic Adhesives— Determination of Torque Strength of Anaerobic Adhesives on Threaded Fasteners. This standard describes testing procedures for liquid and preapplied sealants using manual and graphical procedures. 

Typical apparatus for torsional measurements is that described by Raumann - and in a modified form by Ladizesky and Ward. The sitmple is fastened betw een two clamps, the lower of which may be fixed in any required orientation, and the upper of which is attached rigidly to a small mirror and then to the lower end of a long phosphor-bronze strip. When the top of this strip is rotated both the suspension and the sample will twist, the former through an angle

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The normal thickness of coating is 5-25 jjim and has low frictional properties, making it an ideal surface on fasteners which reduces the tightening torque and prevents jamming. It also provides an effective barrier to prevent bimetallic reaction between steel fasteners and aluminium, e.g. where parts are fixed to an aluminium framework. Cadmium-plated surfaces can be easily soldered without the use of corrosive fluids. 

Installation Manual If available, most likely will not reflect current installation techniques. Basic information such as guidance on fastener installation may not be defined (torque, anti-seize or dry etc). Available, most likely will reflect current installation techniques. Installation method can be tailored to contractor s preferred installation methods. 

P(10) Finger-tight joints are those with some clamping and lateral constraint in the vicinity of bolt holes provided by lightly torqued fasteners. 

P(11) Torqued fasteners are those with substantial clamping and lateral constraint provided by fasteners tightened to a pre-set torque. 

Three connections (Table 1) had mechanical fastening by M16 grade 8.8 steel bolts with 30 mm diameter standard size washers. These were tightened to a torque of 23.8 N m, as recommended in reference 1 for FRP bolts. To aid buildability in connections Wmj bt, Wmj bt+bd and Wmj bd, bolt holes had a clearance of 2 mm. After test Wmj bt was conducted, the specimen was modified such that the holes in the members and cleats (Figure 3) were re-drilled to provide a tight fit for M20 steel bolts. This additional test, Wmj bt.2, was conducted for a number of reasons (reference 10). 

Metal fasteners of high strength can overstress plastic parts, so torque-controlled tightening or special design provisions are required. Where torque cannot be controlled, various types of washers can be used to spread the compression force over larger areas. 

Couple k3-p3l couple of if often k9-pl9 [ME, pair, bond, ff. OF cople, ff. L copula bond, fr. co- + apere to fasten] (13c) n. Two equal and oppositely directed parallel but not coUinear forces acting upon a body to form a couple. The moment of the couple or torque is given by the product of one of the forces by the perpendicular distance between them. Dimension [M L T j. 

Metal fasteners of high strength can overstress plastic parts, so torque-controlled tightening or special design provisions are required. 

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