MECHANICAL ISOLATION OF HYDRAULIC NOISE SOURCES
Vibration characteristics of hydraulic piston pumps and other pertinent vibration sources are identified to guide the design of pump vibration isolation mountings. In the study vehicle, a harvesting machine, cab noise reaches 98 dB(A) when the machine is driven to and from fields at top speed. Noise sources include the drive shaft, piston pump, gear pump, piston motor, and bevel gear. Since noise heard outside the cab is not detected in the cab, the cab effectively shields the operator from airborne noise. As a corollary to this, it is concluded that cab noise is due to structureborne noise vibrating cab walls. The absence of strong engine noise components also leads to the conclusion that engine vibration mounts are effective in isolating structureborne noise. Cab noise can also be reduced by isolating other sources of structureborne noise. Piston pumps generate structureborne noise in three ways: periodic variations in torque or moments generated by the pump; discharge flow pulsations or fluidborne noise, generating structureborne noise by exciting vibrations in hydraulic lines; and cyclic forces internal to the pump. Isolating a pump requires a resilient mounting system that blocks the transmission of linear motions in two directions and rocking motions in one or two planes. Simplification in noise reduction can be achieved with the use of mounting systems and reported design data for avoiding coupled vibration modes. The selection of an appropriate design frequency for designing a pump isolation system, coupled vibration modes, and inclined mounts are detailed.
- Find a library where document is available. Order URL: http://worldcat.org/issn/01487191
- Presented at SAE Off-Highway Vehicle Meeting and Exposition, Milwaukee, Wisconsin, 11-14 September 1978.
Warrendale, PA United States 15096
- Skaistis, S J
- Publication Date: 1978
- Features: References;
- Pagination: 10 p.
- TRT Terms: Cabs (Vehicle compartments); Damping (Physics); Hydraulic equipment; Noise control; Pistons (Engines)
- Old TRIS Terms: Mounting
- Subject Areas: Safety and Human Factors;
- Accession Number: 00399012
- Record Type: Publication
- Source Agency: National Highway Traffic Safety Administration
- Report/Paper Numbers: SAE 780759, HS-025 580U
- Files: HSL, USDOT
- Created Date: Aug 31 1985 12:00AM