| 摘要 |
An improved head for use with a concrete vibrator for settling concrete/aggregate is provided. The head includes a hollow casing with an eccentric rotor having a curved segment along one side and supported for rotation by a bearing at a first or drive end. A second bearing is provided adjacent a second, distal end of the rotor. In one embodiment, the second bearing includes a bushing of disparate material, such as brass. A lubricant in the casing forms a thin, high pressure oil film between the bushing and the internal surface of the distal end cap, as well as between the curved segment of the rotor and the internal surface of the casing. Since the eccentricity of the rotor is extended, enhanced vibration is obtained. In this first embodiment, the bushing is brazed to the distal end of the rotor and the casing is steel. The bushing is arcuate and is positioned in close proximity to the internal surface of the distal end cap along the curved segment and at its axial edge. A leading bevel edge on the bushing, as well as the rotor, assists in capturing the lubricant to form the thin film as the rotor rotates. In a second embodiment, single rotary bearings support the ends in conjunction with the hydraulic bearing formed between the rotor and the internal surface of the casing.
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