Basic Selection of Gearbox Reducer

Basic Selection of Gearbox Reducer

Gearbox reducer selection can be quite difficult. Customers have a variety of gearbox reducers to choose from that are capable of fulfilling diverse requirements. A wrong decision could result in the purchase of a more expensive gearbox. The power transmission industry may need a gearbox that will support overhung loads while the motion control or servo industry may need a gearbox that will handle dynamic motion.

サイジングの最初の問題領域の1つは、サイジングからモーターへのサイジングと負荷へのサイジングから生じます。モーターへのサイズはより単純で、機能するギアボックスになりますが、必要以上に大きなギアボックスを購入することになります。このギアボックスは、アプリケーションの資格も過剰になります。ただし、負荷に合わせてサイズを変更すると、ギアボックスがアプリケーションに適合し、費用対効果が高く、フットプリントが小さい場合があります。

Common Aspects of Sizing Applications

あらゆる状況に適用されるギアボックスのサイジングにはいくつかの側面があります。このセクションでは、これらの基準を詳しく説明し、洞察を提供します。

1。サービスファクター

Before sizing an application, the customer should determine the service factor.
Service factor can be generally defined as an application’s required value over the rated value of the unit. Service factor should be determined for conditions such as non-uniform load, hours of service, and elevated ambient temperature.

How would one interpret a service factor? A service factor of 1.0 means a unit has just enough capacity to handle the application. There is no tolerance for additional requirements, which could cause the gearbox to overheat or fail. For most industrial applications, a service factor of 1.4 is adequate. This service factor signifies that the gearbox can handle 1.4 times the application requirement. If the application requires 1,000 inch-pounds, the gearbox would be sized to handle 1,400 inch-pounds. Different factors will affect how much service factor should be used in a given application.

2。周囲温度と環境

Higher ambient temperatures increase internal pressure, which will require an increase to the service factor used. High or low temperatures can require different seal materials and lubrication viscosities. The environment the gearbox will operate in is also an important consideration for sizing. Harsh environments can increase wear on the unit. Dusty or dirty environments often require special material to prevent corrosion or bacteria growth. Food or beverage plants require specific FDA compliant coatings and oil. Vacuum environments will require special grease and heat dissipation considerations, since there will be no air for cooling. Failure to account for these environmental features can result in a gearbox that cannot support the application properly. All of these aspects must be considered when sizing a gearbox.

3。衝撃負荷または負荷の種類

高い衝撃または衝撃荷重は、ギアの歯とシャフトベアリングの摩耗の増加を引き起こす可能性があります。この摩耗は、サイジングを考慮していない場合、早期の故障を引き起こす可能性があります。これらの負荷には、サービス係数が増加する必要があります。均一な負荷は、アプリケーション中は一定のままである荷重であり、アプリケーション中は不均一な負荷が変化します。不均一な負荷は、たとえ小さい場合でも、均一な負荷よりも高いサービスファクターが必要になります。均一な負荷の例は、それに乗っている一貫した製品量を備えたコンベヤーです。不均一な負荷は、あらゆる種類の断続的な切断アプリケーションです。この断続的な切断力は、ギアボックスのトルクの周期的な増加を引き起こします。これは不均一な負荷です。

4。出力スタイルまたはメカニズム

出力メカニズムには、スプロケット、プーリー、または歯付きピニオンが含まれます。二重出力シャフトやシャフトに取り付けられたブッシングなどの異なる出力構成により、ユニットの定格の張り出し荷重量が減少します。異なる出力メカニズムは、考慮する必要があるさまざまなシャフト荷重を追加します。ほとんどのメカニズムは放射状の荷重が高くなりますが、ヘリカルギアリングのようなものは軸荷重を引き起こす可能性があります。これらの出力は、放射状または軸の負荷の増加を説明するために異なるベアリングを必要とする場合があります。

5。出力シャフトまたは中空のボアサイズ

When sizing an application, the output shaft and bore size must meet customer requirements. These could include a stainless output on the unit, and whether it has a keyed or keyless shaft, a keyed or keyless hollow bore, or a flanged output combined with any of the previous. Getting the correct bore size on a unit may force the customer to purchase a larger gearbox or a different style of gearbox to fit their current shaft. In some instances, the customer can modify their shaft to use the most cost-effective unit while providing an optimal solution.

6。ハウジングスタイル

It is also important when selecting a gearbox to consider how it will mount. A unit could have mounting feet, a flange on the output, or just basic tapped holes on one or more sides. These housing styles could limit how a unit is mounted so having a variety of options could prevent custom frames or brackets from being needed. For example, having tapped holes on the bottom face of the unit would prevent the need for a special L-bracket to mount around the output.

Power Transmission

Some elements that affect the sizing process are industry specific. For the power transmission industry, output RPM, motor horsepower and frame size, and overhung load all impact the application calculations.

• 出力rpm The customer must determine the ratio needed for the gearbox reducer to operate, or provide input/output speed and operating hertz (Hz) for calculations. The standard is a 1750 input RPM at 60 Hz. Any changes will need to be specified when sizing as it will change the ratio calculation. Failure to account for changes will result in a gearbox that does not match the customer’s requirement.

• Motor HP and Frame Size The gearbox reducer size and input option must be determined before calculating the service factor. Once the gearbox is sized, use the required HP to compute the actual service factor. Large HP motors generate heat that can adversely affect the reducer’s mechanical ratings. This reduced rating, based on the increased heat, is known as the Thermal Capacity of a reducer, and must be considered when using large motors.

• General Shaft Load サイジングは、負荷がギアボックスに損傷を与えないことを確認する必要があります。ポンドで測定された力は、出力シャフトが維持できるということです。評価がアプリケーションよりも少ない場合、速度低下は損傷します。

Motion Control

サーボ産業の場合、入力速度、慣性、動的トルクの動き、特定のシャフト荷重、モーターシャフトの直径がサイジングプロセスに影響します。

• Input Speed Input speed should not exceed the gearbox ratings or premature seal wear will occur due to increased pressure. Input speed can be accidently increased if there is an output mechanism with a ratio that is not considered when sizing, which is another reason why specifying any output mechanisms is so important.

• Inertia An inertia mismatch of less than 10:1 is desired for fine controlling of the output. This is important to obtain the high accuracy needed for some applications. Reducer size and ratio are main influences from the gearbox on inertia. Control engineers may request smaller mismatches or even specific amounts. Often a motor is chosen for its dynamic capabilities, not for its torque. It is common to use a motor with much more torque than needed for the application due to its increased rotor inertia. Some motor manufacturers even make motors specifically for high or low inertia ratings. This allows for better tuning of the application because of a lower inertia mismatch. When doing this, it is important to limit the output torque in the motor to prevent breaking the gearbox

• Dynamic Motion Cyclic motion may require using a higher service factor than continuous motion. This is because constant starts and stops cause additional wear on the gear teeth and seals. Cyclic reversing, which is constant back and forth motion between two points, requires an even higher service factor than cyclic or continuous

• Specific Shaft Loads ラジアル、軸方向、およびモーメントシャフトの荷重は、ユニットの評価に対してチェックする必要があります。これを行うことに失敗すると、シャフトが壊れたり、ベアリングや歯車の歯が損傷したりする可能性があります。一般に、これらの評価に同じサービス係数が適用され、適切に強力なギアボックスが決定されます。追加のベアリングタイプは、アプリケーションに必要な場合、これらの評価を増やすことができます。

• Motor Shaft Diameter or Length モーターシャフトはユニットに収まる必要があり、シャフトはカップリングとの完全な関与に十分な長さでなければなりません。完全なエンゲージメントがなければ、入力滑りが発生する可能性があります。これは必要なサービスファクターには影響しませんが、モーターの取り付けの問題を避けるために考慮することが重要です。一部のメーカーには、ユニットサイズを増やすことなく、還元剤がより大きなモーターに対応できるようにする大きな入力設計があります。

Conclusion

To achieve the best gearbox reducer solution, customers should size from the load. This will ensure they receive cost effective solution that fits the application. The service factor, environment, ambient temperatures, shock load, output style, and hours of service are all important aspects for sizing. The more information the customer provides, the more accurate the sizing process. This will ultimately yield a solution that matches the customer’s requirements! There are numerous sizing programs available that can help determine what gearbox is most appropriate for your application.