Helical gears or spur gears?

 

Gears are a key component of mechanical motors and actuators. They increase the output torque and control the direction or speed of rotation. CLR has extensive experience in the manufacture of plastic and metal gears of various shapes and sizes: spur gears, incandescent empty gears, planetary gears and helical gears; Sprockets, bolts or other types of teeth. Among them, helical and spur gears are generally the most widely used in many industrial applications? Would you like to know more about the differences and characteristics? This article can help.

Helical gear: advantages and disadvantages.

Helical gears work smoother and quieter than spur gears. This difference is due to the oblique way in which the teeth interact with respect to the axis of rotation. These axes can be parallel or generally intersect at 90 °. In the case of crossover, helical gears are applied together with helical gears, but in this case two bevel gears can be used alternately.

When the two teeth move, contact is made gradually, starting at one end of the teeth and continuing in contact with the gears, rotating until they are in full contact. Typical helix angles are about 15 to 30 degrees. Thrust load, on the other hand, varies in direct proportion to the size of the propeller angle tangent.

Finally, a closer look at the types available may highlight the following:

·         Cross Shaft Worm Gear: The simplest within the Worm Gear category. They act like a screw or wedge as a result of high slip along the side of the tooth.

·         Parallel Shaft Helical Gears: Consists of an infinite number of low thickness staggered spur gears. This will angle each tooth along the side like a cylindrical helix. When in contact with each other, the spiral angles must be the same, but the directions must be opposite. As a result of the helix angle, there is an axial thrust in addition to the load.

·         Double helix or "herringbone": a combination of right and left helix. The axial thrust absorbed by the worm gear bearings is a disadvantage.

Advantages of Helical gear

·         Angle gears run more gradually, allowing smoother, quieter gear operation compared to sprockets or tooth wheels.

·         Helical gears last longer and have more teeth in contact, making them ideal for high load applications.

·         The load is always spread across multiple axes, reducing wear.

·         It can transfer motion and forces between parallel and perpendicular axes.

 

 

Disadvantages

·         One of the drawbacks of these gears is the thrust that occurs along the gear axis, which must be accommodated by a suitable thrust bearing. There is a higher level of sliding friction between the teeth. This increases wear during operation and requires a lubrication system.

·         The efficiency of the helical gear is low because it generates axial thrust and heat due to the contact between the teeth. The greater the energy loss, the less efficient it is.

·         Higher manufacturing cost than spur gears.

 

Spur gear: advantages and disadvantages.

Spur gears are the most common type of gear and are distinguished from other gears because the gears are positioned along a parallel axis. They are used to achieve large gear ratios, low and medium speeds. Spur gears are very useful when you need to transfer motion from one axis to a close parallel axis.

Advantages of spur gears

·         It can be used to transmit a significant amount of power (up to about 50,000 kW).

·         They are very reliable.

·         This piece is the simplest piece to design and manufacture. Job projects that contain spur gears can be implemented more quickly.

·         They provide a constant and stable gear ratio.

·         Spur gears are more efficient compared to helical gears of the same size.

·         No axial force is generated because the teeth are parallel to the axis. Therefore, the gear shaft can be easily mounted by ball bearings.

 

Disadvantages

·         Low speed gear.

·         Power cannot be transferred between non-parallel axes.

·         Spur gears make too much noise when running at high speed.

·         The teeth of the wheel are under a great deal of stress.

·         It cannot be used for long-distance power transmission.

·         It is not elastic compared to other types of gears.

For applications, it is common for applications where slow motion is required and the noise level is not critical, such as in the vending machine or security system industry. They also serve important applications by transmitting motion within a planetary gear motor.