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Belt Drives 2. Wedge V-Belts V-belts not optimum of load transfer Wedge V-belts overcome this: Greater depth to width ratio Given width, higher power ratings than V-Belts Up to 3 times greater power than V-Belts Notched Wedge V-Belts Notches maximize the degree of bend
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Belt Drives 2 • Wedge V-Belts • V-belts not optimum of load transfer • Wedge V-belts overcome this: • Greater depth to width ratio • Given width, higher power ratings than V-Belts • Up to 3 times greater power than V-Belts • Notched Wedge V-Belts • Notches maximize the degree of bend • Allows smaller sheaves and space savings • Severe duty applications, high starting loads
Belt Drives 2 • Belt Designation: • 5V X 1500 • 5V = Standard cross section (3V, 5V, 8V) • X = Notched belt • Belt length in tenths of an inch (150.0 in) • Belt Installation • Never rolled, pried on or forced on a drive • Proper way: • Release the drive • Slip belt of the sheave • Tighten the drive
Belt Drives 2 • Multiple-Belt Drives • Great power with inexpensive components • 2 wedge V-Belts and 2 double grooved sheaves • Belt Types • Use matched sets of belts from same manufacturer • Same characteristics • Same performance • If belt breaks • Replace all belts • New belts share the load equally
Belt Drives 2 • Multiple Speed Belt Drives • Frequent and fixed speed ratios must be obtained • Pulley utilized – Step-cone pulley • Multiple grooves with different pitch diameters
Belt Drives 2 • Variable speed belt drive • Varying and precise and precise speed ratios must be obtained • Pulley utilized – variable pitch pulley • Groove width can be adjusted and locked • Groove width raises and lowers the belt in the groove to locate the pitch line needed for desired speed ratio
Belt Drives 2 • Pulley Idlers • Adjust the tension, guide along a path or avoid obstacles • 2 configurations • Inside – idler mounted inside the belt loop • Adds tension • Diminishes belt wrap around the pulleys • Outside – idler mounted outside the belt loop • Adds tension • Increases the belt wrap around the pulleys
Belt Drives 2 Alternator (1), Idler pulley (2), P/S Pump (3), A/C Compressor pulley (4), Crankshaft pulley (5), Accessory Drive Belt tensioner (6), Accessory Drive Belt (7)-4.0L engine
Belt Drives 2 • Synchronous Belt Drives • Used when precise and constant speed ratios required • Referred as timing belts • Timing belt pulleys • Flat belt with evenly spaced teeth • No slip • Longer life than V-Belts • Belt Pitch • Distance between points between the teeth • Maintain constant and precise speed rations