06-08-2022, 09:18 PM
(This post was last modified: 06-08-2022, 09:23 PM by Colin Morgan.)
Spiral bevel gears are best with EP?
"Hypoid gears have axes that are non-intersecting and not parallel. In other words, the axes of hypoid gears are offset from one another. The basic geometry of the hypoid gear is hyperbolic, rather than having the conical geometry of a spiral bevel gear.
In a hypoid gear, the spiral angle of the pinion is larger than the spiral angle of the gear, so that the pinion diameter can be larger than that of a bevel gear pinion. This offers more contact area and better tooth strength, which means that more torque can be transmitted and high gear ratios (up to 200: 1) can be used. Because hypoid gear shafts do not intersect, bearings can be used on either side of the gear to provide additional rigidity.
The difference in spiral angles between the pinion and the crown (larger gear) causes some sliding along the teeth, but the sliding is smooth, both in the direction of the tooth profile and lengthways. This gives hypoid gears very smooth running properties and quiet operation. However, due to the pressure between the teeth, special EP (Extreme Pressure) gear oil is also required to maintain effective lubrication."
("The main difference between GL-4 and GL-5 gear oils is the amount of EP additives. Sulfur/Phosphorus-containing products are used as EP-additive. This additive has the purpose to prevent the occurrence of micro-welds on the gear flanks at the local high temperatures which prevail in EP circumstances (temperatures well in excess of 800℃!) GL-5 has roughly twice the amount of EP additives compared to GL-4, which is why it is often used in high-pressure circumstances such as in a front axle and rear axle differential.
However, sulfur/phosphorus additives have an unfavorable property: they can react aggressively to bronze and copper. ... Therefore, it is not recommended to use GL-5 ... unless the manufacturer allows it.")
"Hypoid gears have axes that are non-intersecting and not parallel. In other words, the axes of hypoid gears are offset from one another. The basic geometry of the hypoid gear is hyperbolic, rather than having the conical geometry of a spiral bevel gear.
In a hypoid gear, the spiral angle of the pinion is larger than the spiral angle of the gear, so that the pinion diameter can be larger than that of a bevel gear pinion. This offers more contact area and better tooth strength, which means that more torque can be transmitted and high gear ratios (up to 200: 1) can be used. Because hypoid gear shafts do not intersect, bearings can be used on either side of the gear to provide additional rigidity.
The difference in spiral angles between the pinion and the crown (larger gear) causes some sliding along the teeth, but the sliding is smooth, both in the direction of the tooth profile and lengthways. This gives hypoid gears very smooth running properties and quiet operation. However, due to the pressure between the teeth, special EP (Extreme Pressure) gear oil is also required to maintain effective lubrication."
("The main difference between GL-4 and GL-5 gear oils is the amount of EP additives. Sulfur/Phosphorus-containing products are used as EP-additive. This additive has the purpose to prevent the occurrence of micro-welds on the gear flanks at the local high temperatures which prevail in EP circumstances (temperatures well in excess of 800℃!) GL-5 has roughly twice the amount of EP additives compared to GL-4, which is why it is often used in high-pressure circumstances such as in a front axle and rear axle differential.
However, sulfur/phosphorus additives have an unfavorable property: they can react aggressively to bronze and copper. ... Therefore, it is not recommended to use GL-5 ... unless the manufacturer allows it.")