Patent Application
20140260783
The present disclosure relates to a damping member for a bolt assembly for a machine component, and more specifically for providing the damping member in order to reduce vibrational excitation associated with the bolt assembly.
Connecting rods used in engines are usually made in sections. The sections of the connecting rod are held together by means of a bolt. The bolt has a natural frequency of vibration. During working of the engine, a frequency of vibration of the engine assembly may match the natural frequency of the bolt. This can result in resonance leading to loosening of the bolt, failure due to fatigue, disengagement of the sections of the connecting rod causing overall damage to the system, and the like.
Methods are known to firmly secure the bolt within the connecting rod. For example, U.S. Published Application Number 2005/262963 discloses a connecting rod having a rod portion, a connecting rod eye and a connecting rod cover. The connecting rod also includes a screw element connecting the connecting rod cover to the rod portion at a region of the connecting rod eye. The connecting rod further includes a securing element disposed in an area between the screw element and one of the rod portion and the connecting rod cover. The securing element braces the screw element with respect to the one of the rod portion and the connecting rod cover.
However the known systems do not have any effect on the frequency of vibration of the bolt. Hence, there is a need to provide an improved design for the bolt in order to dampen the vibrational excitation experienced by the bolt.
In one aspect of the present disclosure, a bolt configured to connect a plurality of sections of a connecting rod assembly is provided. The bolt includes a head portion. The bolt also includes a body extending from the head portion. The bolt further includes a damping member affixed to the body of the bolt. The damping member is configured to dampen a vibrational excitation associated with the bolt.
In another aspect of the present disclosure, a connecting rod assembly is provided. The connecting rod assembly includes a connecting rod arm. The connecting rod assembly includes a connecting rod cap. The connecting rod assembly also includes a bolt configured to join the connecting rod arm and the connecting rod cap. The connecting rod assembly further includes a damping member affixed to the bolt. The damping member is configured to dampen a vibrational excitation associated with the bolt.
In yet another aspect of the present disclosure, a method is provided. The method provides a connecting rod arm and a connecting rod cap. The method also provides a bolt for mechanically coupling the connecting rod arm and the connecting rod cap. The method then affixes a damping member to the bolt. The damping member is configured to dampen a vibrational excitation associated with the bolt. The method further receives the bolt affixed with the damping member into the connecting rod arm and the connecting rod cap.
Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.
Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or the like parts.
The bolt 216 may possess a natural frequency of its own. During operation of the engine, the natural frequency of the bolt 216 may match to that of the engine assembly 100. This may cause the bolt 216 to vibrate at a resonating frequency leading to resonance. Resonance may cause loosening of the bolt 216 and/or fatigue failure of the bolt 216 over a period of time. Resonance is, therefore, undesirable and detrimental to the bolt 216, the connecting rod assembly 106, and also the engine assembly 100. Hence, resonance needs to be avoided by preventing the bolt 216 from vibrating at the resonating frequency.
The present disclosure relates to a damping member 302 affixed to the bolt 216 as shown in
More specifically, the damping member 302 may be affixed to the bolt 216 in a variety of ways. For example, the damping member 302 may be externally attached to the body 306 of the bolt 216 or may be integrally molded onto the body 306 of the bolt 216. The bolt 216 and the damping member 302 may be fastened within the bore of the connecting rod assembly 106. The damping member 302 may prevent direct contact of the body 306 with an inner surface of the bore defined in the connecting rod assembly 106. Thus, the damping member 302 may insulate the bolt 216 from the vibrations of the connecting rod assembly 106.
The damping member 302 may be made of any material including any malleable metal, polymer, elastomer or any other damping material known to one skilled in the art.
Referring to
Further, one or more raised surfaces may be formed on the damping member 302. For example, the damping member 302 may have a ringed configuration in the form of rings 314 (as shown in
The rings 314 on the damping member 302 made of the elastomeric material may be formed by molding. It should be noted that use of the polymeric or elastomeric material include ability to create finer configurations on the damping member 302 like close spacing of the rings/helix to each other, ability to easily fit into the bore of the connecting rod assembly 106, etc. The rings 314 and the protrusions 604 on the damping member 302 made of the malleable metal may be formed by stamping or any other known process.
As shown in
Further, the damping member 302 may be located anywhere along the body 306. Preferably, the damping member 302 should be provided proximate to the head section 304 of the bolt 216. For example, the damping member 302 may be provided in a first half section or a first quarter section of the body 306 proximate to the head section 304 of the body 306. Additionally, a second damping member 302 may be provided in a second half section or a second quarter section of the body 306 proximate to the bottom section 308 of the body 306. Also, the damping member 302 may be placed either over an unthreaded or threaded portion of the body 306.
It should be noted that the materials for the damping member 302 and the configurations may be varied and may be interchanged without deviating from the scope and spirit of the disclosure. The designs shown herein are merely exemplary and do not limit the scope of the disclosure. Moreover, dimensional parameters of the damping member 302 like length, thickness, type of configuration formed on the inner and/or the outer surface and the location and number of the damping members 302 that may be used on the body 306 of the bolt 216, may vary as per system design and requirements and may not limit the intended scope of the disclosure.
Bolts used to join the sections of the connecting rod assembly possess natural frequencies of their own. During operation of the engine, the energy and vibrations of the system get transferred to the bolts through the connecting rod. This transfer of energy and vibrations may cause the bolts to vibrate at resonating frequencies. These resonating frequencies are detrimental and undesirable as they may lead to loosening of the bolts, structural fatigue failures of the bolts, and the like causing catastrophic damage to the overall engine assembly.
The present disclosure relates to the damping member 302 that may be used to prevent the bolt 216 from vibrating at the resonating frequency and prevent failure of the bolt 216. The damping member 302 may be affixed to the body 306 of the bolt 216. This may lead to reduced strain in the bolt 216 in order to have an acceptable fatigue life. The damping member 302 may result in a considerable increase in a fatigue factor of the bolt 216, thereby resolving field failures.
Referring to
After affixing the damping member 302 over the body 306 by an appropriate fastening method, at step 808, the bolt 216 along with the damping member 302 and the washer 704 may be received in the bore 702 of the connecting rod assembly 106.
The thickness of the damping member 302 may be so selected so as to create the force fit or the interference fit, as per system design and requirements. The damping member 302 may rest between the bore 702 and the bolt 216. Hence, the damping member 302 may insulate the bolt 216 from the energy and vibrations of the connecting rod assembly 106. This in turn, may prevent the bolt 216 from vibrating at detrimental and undesired resonating frequency.
It should be understood that apart from the bolt 216 installed on the connecting rod assembly 106, the damping member 302 may be used on fastening members used on a variety of other applications. Fastening members may include screws, rivets, clamps, etc. used on various industrial and commercial machines, vehicles and the like which are subjected to detrimental vibrations during their operation.
While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.
