The Pivotal Role of Shafts in Car Engineering - Essay Example

Student’s Name Instructor’s Name Course Date Shafts Shafts play a pivotal role in engineering. Gear systems require shaft connection to function as required. They are responsible for transmitting rotational power and motion from the gear. The effective design and analysis of a shaft requires the use of the distortion energy theory of failure. Determining the rotational speed of the speed is the first issue of concern in the shaft design. Secondly, it is vital to determine the torque that the shaft will transmit. The next stage entails determining the other devices or components attached to the shaft including their specific locations. In the fourth step, the engineer should determine the location of the shaft bearings that will support it. In most cases, two bearings support the shaft. However, it is important to place the bearings on either sides of the shaft to ensure a well-balanced bearing loading and effective support of the shaft (Childs 84). The fifth step entails determining the shaft’s geometry. The step includes determining the position of each of the shaft elements and the transmission of power from each of the elements to the shaft. Next, the engineer should draw a torque diagram that determines the torque’s magnitude at each of the positions. The seventh step entails determining the radial and axial forces exerted on the shaft followed by resolving the radial forces in horizontal and vertical forces. In the next step, one should solve for the reactions in each plane of the support bearings followed by producing the bending moment diagrams and the complete shearing force to aid in determining the distribution of the shaft’s bending moments. The next step entails selecting the material to be used in producing the shaft followed by determining the appropriate stress of design with reference to the way of loading. Analyzing the shaft’s critical moments suffices to be the next step. It enables the determination of the minimum diameter that ensures safety during loading. Finally, the engineer should specify the final diameters at each point of the shaft (Childs 85). Springs The design of springs utilizes three basic principles. Firstly, the strength of the spring is directly proportional to the wire’s thickness or weight. Secondly, the strength of the spring is inversely proportional to the size of the coil. Finally, the number of active coils of the spring is inversely proportional to the load that one has to apply to move the spring through the required distance. The design steps for a spring starts with setting up the coils. The first step of the phase entails estimating the amount of arbor required to accommodate the spring. After mounting the drill firmly in its place, preferably a vise, chuck up the arbor (Loretta 20). The mounting of the drill should be in such a way that it is in front of your left shoulder. One should also ensure that the diameter of the arbor is slightly less than the inside diameter of the spring. The next step entails getting the piece of wire that may be several feet long, cutting it from the coil and making a 90o bend in one end. The next step entails putting the wire into the arbor. Next, stick the dogleg wire end between the two uppermost jaws of the drill chunk and shoving it in to the end of the wire bend. The next step entails bringing the wire guide near enough so that the wire catches the pin’s groove. It is important to ensure that the wire is away from the chunk. In the seventh step, turn on the drill and put your finger on the trigger while maintaining a low speed. By so doing, the wire guide kicks upwards requiring one to steady it using the right hand. The guide also slides to the right requiring the engineer to continuously move the right hand to the left until the wires lie flat against one another. The next step entails reversing the drill slowly to hang the coils freely on the arbor. Next, slide the coils and wire guide off the arbor. Finally, determine the coil’s diameter to find out if it is what you want. If it is not, repeat the procedure using a different arbor until you attain the required diameter (Loretta 21). Bearings Bearings are machine elements that enable components to move effectively with one another. There are sliding contact and rolling contact bearings. In sliding contact bearings, the engineers locate the shafts radially with no available axial location. On the other hand, the rolling contact bearings use rollers and balls to prevent the sliding of materials in contact. The ball bearings consist of spheres manufactured from high quality, hardened and polished materials that roll in rings or races. However, the size of the bearings depends on their intended purpose. The cage is responsible for spacing the bearings uniformly around the races. It also prevents contact between the bearings. Therefore, the engineers should note that installing the cages is the last step in the assembly process. By preventing the bearings from making contact with one another, the cage prevents the rapid wearing and scuffing of the bearings (Childs 62). It is also imperative to lubricate the bearings since friction between the balls and the sliding effect are available. Besides the existence of the deep groove ball bearings that run in races of shallow notches, there also exists the filling notch ball bearings that also comprises of notches. However, the engineers cut out the notches on one side of both the outer and inner races. The engineer slips the required number of balls into the raceways prior to using the cage to space them in the case of the deep groove bearing. However, one point of concern associated with using the filling notch ball bearings is the resultant slight discontinuity of the paths of the ball bearings. The discontinuity impacts negatively on the life of the bearings. In situations that require both radial and axial loading, angular contact ball bearings are effective. However, the orientation of the inner and outer races implies that one side of the groove has more contact with the bearings than the other side (Childs 63). As a result, it is imperative to mount the bearing in the correct orientation to enable it withstand the axial load. Seals Seals are responsible for preventing potential leaks of a fluid. Elastomers are used to manufacture O-rings. Some of the elastomers encompass Buna N, NBR and Nitrite. However, it is imperative to blend the elastomers so as to increase the resistance of the resultant products to extreme temperatures, light and certain fluids. Upon the blending of the ring with respect to the machine groove, the engineer installs the seal on the groove. The O-ring is one of the examples of the available seals in engineering. The engineer places the O-ring on one of the surfaces of the materials that require sealing (Childs 188). Upon bringing the two surfaces that require sealing together, they squeeze the O-ring’s cross-section thus deforming it. It is important to note that the deformation of the cross-section increases with the increase in the squeezing action. The O-ring uses an incompressible, highly viscous fluid that also has a high surface tension that enables it to remember the original shape for a long time. As a result, the O-ring suffices to be a good seal as compared to the other seals. It is imperative for the engineers to understand the performance of the O-ring under low pressure scenarios. As a matter of fact, it is evident that deformation occurs when the O-ring is subjected to pressure. Moreover, the propensity of the elastomer to maintain the original shape after deformation results in the formation of the seal. The force that the O-ring exerts on the mating surfaces is equivalent to the force that the mating surfaces exert on the O-ring to deform it. The contact bands that forms the area between the mating surfaces and the O-ring prevent the passage of the fluid thus acting as a seal. However, in the event of higher pressure, the fluid pressure augments the sealing action of the O-ring thereby forcing the O-ring away from the pressure to the side of the gland (Childs 189). The O-ring exerts pressure in all directions apart from the gap between the surfaces. Fasteners Fasteners consist of bolts and rivets that serve the same purpose despite the fact that they exhibit different physical appearance. The design of rivets depends on the behavior of the rivets when subjected to different loading conditions. Therefore, it is mandatory that the engineer should note the rivet’s tensile capacity and strength. They should also note that the rivet’s shear resistance is directly proportional to the number of critical shear planes and the available shear area. Therefore, the engineers should understand that rivets are either subjected to tension or shear or both tension and shear (Kulak et al. 33). Therefore, the design of rivets subjected to tension requires the engineers to understand that the tensile capacity is equivalent to the rivet’s tensile strength and its cross-sectional area. The tensile strength may also exceed the undriven strength of the rivet by 10 to 20%. The ASTM does not specify the tensile capacity. As a result, the engineers should use 60 ksi and 80 ksi as the lower bound estimates for the A502 grade 1 and 2 rivets respectively. Gears There are three classes of gears: helical, spur and worm gears. The design of the gear starts with determining the gear materials. Some of the desirable properties for effective gear materials encompass the endurance strength of the materials to prevent bending failure, the surface endurance strength that averts destructive pitting, low friction coefficient to avert scoring and minimal thermal distortion during heat treatment. The first step of the gear design procedure is the determination of the transmitted power, the life spun of the gear, gear ratio, pinion and speed. The engineer obtains all the above information from the problem statement. The next step entails selecting the most appropriate material with reference to the gear ratio and transmitting power (Sainath et al. 821). Apparently, the pinion material should be stronger than the gear material since the more loading cycles are associated with the pinion as compared to the gear. Using the design data book, the engineer should note the bending stress and the design surface compressive stress for the material selected to develop the gear. With reference to the surface compressive stress, the engineer should determine the gear drive’s minimum center distance. The next step entails selecting the next standard table from the table. Next, the engineer should use the minimum center distance and the standard module to correct the number of teeth on the pinion. The corrected number of teeth and the standard module enables the determination of the center distance. In the next step, one should find the pitch circle diameter for both the gear and the pinion. The engineer then finds the face width and opts for the higher value followed by the calculation of the pitch line velocity. During the step, the engineer should note the values of the load concentration factor and the dynamic load factor from the PSG table. The next step entails determining the bending stress and the induced surface compressive stress. Finally, the engineer should evaluate the other parameters of the gear such as the tipcircle diameter, the circular pitch, the root circle diameter and the addendum (Sainath et al. 822). Works Cited Childs, Peter RN. Mechanical design. Hodder Arnold, 1998. Kulak, G. L., J. W. Fisher, and J. H. A. Struik. "Guide to Design Criteria for Bolted and Riveted Joints. American Institute of Steel Construction." Inc., Chicago (2001). Loretta, H. "How to Make Springs." (2000). Sainath, I. Aravind. "Design of Spur Gear and its Tooth profile." Journal of Engineering Research and Applications (IJERA) ISSN 2248: 9622. Read More

Finally, the number of active coils of the spring is inversely proportional to the load that one has to apply to move the spring through the required distance. The design steps for a spring starts with setting up the coils. The first step of the phase entails estimating the amount of arbor required to accommodate the spring. After mounting the drill firmly in its place, preferably a vise, chuck up the arbor (Loretta 20). The mounting of the drill should be in such a way that it is in front of your left shoulder.

One should also ensure that the diameter of the arbor is slightly less than the inside diameter of the spring. The next step entails getting the piece of wire that may be several feet long, cutting it from the coil and making a 90o bend in one end. The next step entails putting the wire into the arbor. Next, stick the dogleg wire end between the two uppermost jaws of the drill chunk and shoving it in to the end of the wire bend. The next step entails bringing the wire guide near enough so that the wire catches the pin’s groove.

It is important to ensure that the wire is away from the chunk. In the seventh step, turn on the drill and put your finger on the trigger while maintaining a low speed. By so doing, the wire guide kicks upwards requiring one to steady it using the right hand. The guide also slides to the right requiring the engineer to continuously move the right hand to the left until the wires lie flat against one another. The next step entails reversing the drill slowly to hang the coils freely on the arbor.

Next, slide the coils and wire guide off the arbor. Finally, determine the coil’s diameter to find out if it is what you want. If it is not, repeat the procedure using a different arbor until you attain the required diameter (Loretta 21). Bearings Bearings are machine elements that enable components to move effectively with one another. There are sliding contact and rolling contact bearings. In sliding contact bearings, the engineers locate the shafts radially with no available axial location.

On the other hand, the rolling contact bearings use rollers and balls to prevent the sliding of materials in contact. The ball bearings consist of spheres manufactured from high quality, hardened and polished materials that roll in rings or races. However, the size of the bearings depends on their intended purpose. The cage is responsible for spacing the bearings uniformly around the races. It also prevents contact between the bearings. Therefore, the engineers should note that installing the cages is the last step in the assembly process.

By preventing the bearings from making contact with one another, the cage prevents the rapid wearing and scuffing of the bearings (Childs 62). It is also imperative to lubricate the bearings since friction between the balls and the sliding effect are available. Besides the existence of the deep groove ball bearings that run in races of shallow notches, there also exists the filling notch ball bearings that also comprises of notches. However, the engineers cut out the notches on one side of both the outer and inner races.

The engineer slips the required number of balls into the raceways prior to using the cage to space them in the case of the deep groove bearing. However, one point of concern associated with using the filling notch ball bearings is the resultant slight discontinuity of the paths of the ball bearings. The discontinuity impacts negatively on the life of the bearings. In situations that require both radial and axial loading, angular contact ball bearings are effective. However, the orientation of the inner and outer races implies that one side of the groove has more contact with the bearings than the other side (Childs 63).

As a result, it is imperative to mount the bearing in the correct orientation to enable it withstand the axial load. Seals Seals are responsible for preventing potential leaks of a fluid. Elastomers are used to manufacture O-rings. Some of the elastomers encompass Buna N, NBR and Nitrite.

Read More