Changing the speed or torque is a task for the transmission. They provide the correct output power on the output embankment of the gear, which makes them key in designing machines and robots. But what happens inside the gear? What is the effect of different steps? How can you connect a high torque with a compact design? We shed light on this subject.
What is a gear ratio?
The gears transfer and transform the torques, speeds, directions of turnover and strength. This is achieved using machine elements such as gears, shafts, belts, rods, etc. There are single- and multi-stage versions. Multi -stage gears have at least two degrees. The gear steps are connected in series and change both speed and torque.
Adding more transmission degrees allows for higher gears. Each additional degree, however, increases the number of components in the transmission. This requires more space and results in more weight and higher purchase cost. Susceptibility to errors also increases, because each degree multiplies the number of potential errors (Gaussian errors propagation).
Reduction or gear ratio?
Each transmission degree is characterized by a specific gear ratio (reducing or increasing). It describes the ratio between the input and output speed. If the speed on the input of the gearbox is higher than on the output of the gearbox (i> 1), this is referred to as a reducing gear. If the speed on the input of the gearbox is lower than on the output of the gearbox (I <1), this is referred to as a ratio that increases speed.
cycloid gearboxes i wave gears are reduction transmission. This means that they reduce the engine speed and at the same time increase its torque. Speed and torque are inversely proportional due to the reduction factor, although efficiency is still very important when calculating the torque.
Reduction (i> 1)
- The speed on the output of the gearbox is lower than on the input of the gearbox
- The torque on the output of the gearbox is lower than on the input of the gearbox
- Speed reducing
Increasing (i> 1)
- The speed on the output of the gearbox is higher than on the input of the gearbox
- The torque on the output of the gearbox is higher than on the transmission input embankment
- Speed gear ratio
The high output torque is beneficial in many cases. It allows you to transfer larger forces, facilitates the transfer of high loads and helps maximize the life and reliability of the machine or robot.
Single-stage and multi-stage cycloid gearboxes
Cycloid gears are available as both single -stage and multi -stage gears. The single -stage cycloid gears are equipped with internal erases. They reach reduction gears to i = 200, have zero slack (because there are no transmission elements) and are offered in very small sizes. However, their reduction factor is limited. Another disadvantage: large eccentrics with their sufficiently high inertia rotate at the speed of the engine. This results in a relatively high level of vibration and a low fatigue factor.
cycloid transmission nabtesco have external erases. This requires the use of an anterior rank of gear and two -stage reduction principle (gear gear and eccentric level). The version with a full shaft therefore has two steps of the gear, and the version with a drilled shaft has three steps of the gear. The total number of transmission degrees is four.
The two -stage reduction principle offers numerous advantages
The degree of gear transmission transfers rotary motion of the propulsion or servomotor to the eccentric shafts. This reduces the speed corresponding to the reduction gear ratio of the input embankment to the toothed gear. Due to the reduced speed, the erases rotate more slowly and may be smaller, which significantly reduces vibrations, and thus improves the material fatigue factor. While the transmission elements cause minimal slack in the first degree, it is negligible because it is reduced in cycloid. The cycloid degree is pre -loaded, which means that it has zero slack. The number of pins and the resulting cycloid level reduction factor allows the tooth lateral clearance to reduce the first degree.
The principle of two -stage reduction not only reduces vibrations and inertia, but also allows for greater reduction. It also results in excellent performance in relation to dynamics and smooth work, as well as high repetition and accuracy. The principle of two -stage reduction is also favorable in terms of profitability. Since the total reduction can only be controlled by the rank of gear, this eliminates the production of various expensive gear housings.
Steps for transmission of cycloid gears and planetary gears
Due to the degree of speed, planetary gears can reach a maximum gear ratio and = 10 to one degree. Comparing the dimensions of planetary and cycloid gears, it can be seen that the total length of planetary gears increases significantly with higher gear ratios. Multi -stage planetary gears are therefore much longer than cycloid gears with the same gear.
Advantages of NABTESCO multi -stage cycloid gears with external eccentrics
- Very high reduction gears in a compact housing
- Flexible adaptation of various reduction gears through the first degree
- Price independence by eliminating different parts of the housing for different reduction gears
- Identical length with different reduction gears
- Lower vibration level and higher fatigue strength
- The smaller number of transmission degrees reduces the complexity of the entire system and minimizes susceptibility to defects
- High profitability thanks to the design of the product, which is compatible with serial production
- Thanks to their design, cycloid gears are stiffer and more compact (about 50% shorter), as well as lighter than multi -stage planetary gears.
wave gears and gear stations
Wave gears always have one degree. Nevertheless, they achieve high reduction coefficients at one degree of gear, with 100% zero ease. It is possible to add subsequent transmission levels (see belt drives or pre -steps of the conical gear to the angular connection of the engine), although it generally eliminates the decisive advantage of zero slack. The exception is the connected wave transmission and cycloid transmission. This design has virtually zero slack and enables high reduction gears with maximum precision. However, to provide zero slack, we always recommend the possible connection between the engine shaft and the gear input or a one -piece solution for the engine shaft and gear.
Nabtesco precise gear ratios in a nutshell
- 2-degree and up to 320
- 3-degree and up to 500
- 4-degree and up to 7000 and more is possible
- 1-stage i = 30-160
In general, higher reduction gears are possible, but this should be considered in strict coordination with the quality requirements of the NABTESCO IATF certificate.
Do you want to learn more about the levels of translating our precise gears or have questions about a specific project? Do not hesitate contact our experts.
