Why are most gears of gear reducer helical?

Gear is an important part of gear reducer. For gear reducer, gear plays an important role. If good gears are used, the advantages of the gear reducer are as follows:

efficient

In the common mechanical transmission, the gear transmission efficiency is the highest, and the closed transmission efficiency is 96%~99%, which has great economic significance for high-power transmission.

The compact structure requires less space than belt and chain drives.

Stable transmission ratio

The stability of transmission ratio is often the basic requirement for transmission performance. Gear transmission is widely used because of its characteristics.

Reliable operation and long service life

The gear transmission with correct design, reasonable manufacture and good use and maintenance is very reliable, and its service life can be as long as ten or twenty years, which is incomparable to other mechanical transmissions.

The gears constituting the gear reducer are divided into helical gears and spur gears. Why are the gears of many gear reducers oblique? We can find the reason by comparison:

1. Compared with spur gears, helical gear reducers have a freer shaft position. For example, the differential transmission shaft with bevel gear does not have to be on the same horizontal plane as the rear axle. If it is straight bevel gear, it is necessary.

2. Reduce the noise. If the gear reducer uses helical gears, the noise will be much lower than that of straight gears at the same speed. The reason is that the helical tooth surface of the gear reducer is in point contact first, then in surface contact, and finally in point contact. Spur gear is the contact of line, surface and line. The transition of helical teeth is smoother. Therefore, the noise generated by the sudden change of contact is much smaller than that of flat teeth.

3. Helical gears have a large contact ratio and a large number of teeth enter the mesh at the same time. Reduce impact and noise, make transmission more stable, and can withstand high speed and heavy load.

4. During processing, the minimum number of teeth to avoid undercutting is small. The corresponding gear head should be small, so under the same transmission ratio of the transmission pair, the volume of the gear reducer with helical gear should be small.

5. It is convenient to produce. A group of helical gear reducers with the same tee number modules and different face widths can be produced on the cylindrical blank with a hobbing machine. Later, it can be cut into different face widths according to customer needs.

However, the transmission of spur gear has poor stability, high impact and noise. The gear reducer applies helical gear transmission with large overlap and good tooth surface contact, so the bearing capacity is high; The minimum number of teeth of helical gear is smaller than that of spur gear, so the mechanism is more compact and the manufacturing cost is the same as that of spur gear. The use of helical gears in gear reducers is more reasonable and applicable to engineering practice.