Tag Archives: harmonic gear

China Professional CZPT Planetary Harmonic Drive Cycloidal Gear Reducer Variable Speed Gearbox gearbox definition

Product Description

GRH specialized in providing hydraulic components and solutions for hydraulic systems.
With continuous improvement and enthusiasm over the past 30 years, CZPT has developed into an emerging power in the fluid power industry since it was established in 1986.

GRH (ZheJiang )  – International Sales Office
GRH (ZheJiang )  –  Manufacturing Facility and Domestic Sales Office
 —————————————————————————————————————————————————   

Production description
 

We can produce motor according to your needs !

 About Us

 Application and Partners

Contact us!

Application: Motor, Machinery, Agricultural Machinery
Hardness: Hardened Tooth Surface
Installation: Vertical Type
Layout: Expansion
Gear Shape: Conical – Cylindrical Gear
Step: Stepless
Samples:
US$ 1050/Piece
1 Piece(Min.Order)

|
Request Sample

Customization:
Available

|

Customized Request

planetary gearbox

Considerations for Selecting Planetary Gearboxes for Aerospace and Satellite Applications

Selecting planetary gearboxes for aerospace and satellite applications requires careful consideration due to the unique demands of these industries:

  • Weight and Size: Aerospace and satellite systems demand lightweight and compact components. Planetary gearboxes with high power density and lightweight materials are preferred to minimize the overall weight and size of the equipment.
  • Reliability: Aerospace missions involve critical operations where component failure is not an option. Planetary gearboxes with a proven track record of reliability and durability are essential to ensure mission success.
  • High Efficiency: Efficiency is crucial in aerospace applications to optimize power usage and extend the operational life of satellites. Planetary gearboxes with high efficiency ratings contribute to energy conservation.
  • Extreme Environments: Aerospace and satellite systems are exposed to harsh conditions such as vacuum, extreme temperatures, and radiation. Planetary gearboxes need to be designed and tested to withstand these conditions without compromising performance.
  • Precision and Accuracy: Many aerospace operations require precise positioning and accurate control. Planetary gearboxes with minimal backlash and high precision gear meshing contribute to accurate movements.
  • Lubrication: Lubrication plays a vital role in aerospace gearboxes to ensure smooth operation and prevent wear. Gearboxes with efficient lubrication systems or self-lubricating materials are favored.
  • Redundancy and Fail-Safe: Some aerospace systems incorporate redundancy to ensure mission success even in case of component failure. Planetary gearboxes with built-in redundancy or fail-safe mechanisms enhance system reliability.
  • Integration: Planetary gearboxes need to be seamlessly integrated into the overall design of aerospace and satellite systems. Customization options and compatibility with other components are important factors.

Overall, selecting planetary gearboxes for aerospace and satellite applications involves a comprehensive evaluation of factors related to weight, reliability, efficiency, durability, environmental resistance, precision, and integration to meet the unique demands of these industries.

planetary gearbox

Recent Advancements in Planetary Gearbox Technology

Advancements in planetary gearbox technology have led to improved performance, efficiency, and durability. Here are some notable developments:

High-Efficiency Gearing: Manufacturers are using advanced materials and precision manufacturing techniques to create gears with optimized tooth profiles. This reduces friction and enhances overall efficiency, resulting in higher power transmission with lower energy losses.

Enhanced Lubrication: Innovative lubrication systems and high-performance lubricants are being employed to ensure consistent and reliable lubrication even in extreme conditions. This helps to reduce wear and extend the lifespan of the gearbox.

Compact Designs: Engineers are focusing on designing more compact and lightweight planetary gearboxes without compromising their performance. This is particularly important for applications with limited space and weight constraints.

Integrated Sensors: Planetary gearboxes are now being equipped with sensors and monitoring systems that provide real-time data on temperature, vibration, and other operating parameters. This allows for predictive maintenance and early detection of potential issues.

Smart Gearboxes: Some modern planetary gearboxes are equipped with smart features such as remote monitoring, adaptive control, and data analysis. These features contribute to more efficient operation and better integration with automation systems.

Advanced Materials: The use of high-strength and wear-resistant materials, such as advanced alloys and composites, improves the durability and load-carrying capacity of planetary gearboxes. This is particularly beneficial for heavy-duty and high-torque applications.

Customization and Simulation: Advanced simulation and modeling tools enable engineers to design and optimize planetary gearboxes for specific applications. This customization helps achieve the desired performance and reliability levels.

Noise and Vibration Reduction: Innovations in gear design and manufacturing techniques have led to quieter and smoother-running planetary gearboxes, making them suitable for applications where noise and vibration are concerns.

Environmental Considerations: With growing environmental awareness, manufacturers are developing more eco-friendly lubricants and materials for planetary gearboxes, reducing their ecological footprint.

Overall, recent advancements in planetary gearbox technology are aimed at enhancing efficiency, durability, and versatility to meet the evolving demands of various industries and applications.

planetary gearbox

Energy Efficiency of a Worm Gearbox: What to Expect

The energy efficiency of a worm gearbox is an important factor to consider when evaluating its performance. Here’s what you can expect in terms of energy efficiency:

  • Typical Efficiency Range: Worm gearboxes are known for their compact size and high gear reduction capabilities, but they can exhibit lower energy efficiency compared to other types of gearboxes. The efficiency of a worm gearbox typically falls in the range of 50% to 90%, depending on various factors such as design, manufacturing quality, lubrication, and load conditions.
  • Inherent Losses: Worm gearboxes inherently involve sliding contact between the worm and worm wheel. This sliding contact generates friction, leading to energy losses in the form of heat. The sliding action also contributes to lower efficiency when compared to gearboxes with rolling contact.
  • Helical-Worm Design: Some manufacturers offer helical-worm gearbox designs that combine elements of helical and worm gearing. These designs aim to improve efficiency by incorporating helical gears in the reduction stage, which can lead to higher efficiency compared to traditional worm gearboxes.
  • Lubrication: Proper lubrication plays a significant role in minimizing friction and improving energy efficiency. Using high-quality lubricants and ensuring the gearbox is adequately lubricated can help reduce losses due to friction.
  • Application Considerations: While worm gearboxes might have lower energy efficiency compared to other types of gearboxes, they still offer advantages in terms of compactness, high torque transmission, and simplicity. Therefore, the decision to use a worm gearbox should consider the specific requirements of the application, including the trade-off between energy efficiency and other performance factors.

When selecting a worm gearbox, it’s essential to consider the trade-offs between energy efficiency, torque transmission, gearbox size, and the specific needs of the application. Regular maintenance, proper lubrication, and selecting a well-designed gearbox can contribute to achieving the best possible energy efficiency within the limitations of worm gearbox technology.

China Professional CZPT Planetary Harmonic Drive Cycloidal Gear Reducer Variable Speed Gearbox   gearbox definition		China Professional CZPT Planetary Harmonic Drive Cycloidal Gear Reducer Variable Speed Gearbox   gearbox definition
editor by CX 2023-09-04

China manufacturer CZPT Planetary Harmonic Drive Cycloidal Gear Reducer Variable Speed Gearbox planetary gearbox application

Product Description

GRH specialized in providing hydraulic components and solutions for hydraulic systems.
With continuous improvement and enthusiasm over the past 30 years, CZPT has developed into an emerging power in the fluid power industry since it was established in 1986.

GRH (ZheJiang )  – International Sales Office
GRH (ZheJiang )  –  Manufacturing Facility and Domestic Sales Office
 —————————————————————————————————————————————————   

Production description
 

We can produce motor according to your needs !

 About Us

 Application and Partners

Contact us!

Application: Motor, Machinery, Agricultural Machinery
Hardness: Hardened Tooth Surface
Installation: Vertical Type
Layout: Expansion
Gear Shape: Conical – Cylindrical Gear
Step: Stepless
Samples:
US$ 1050/Piece
1 Piece(Min.Order)

|
Request Sample

Customization:
Available

|

Customized Request

planetarygearbox

Planetary Gearbox Components

The basic components of a planetary gearset are an input, output, and stationary position. Different types of planetary gearboxes will have different output ratios and torques. A leading company for planetary gearbox design, CZPT, provides the necessary components. These components can vary in both male and female shafts and come with a variety of modular options. Here are a few things to consider about each component.

CFHK Series

The CFHK Series is a multistage planetary gearbox that contains multiple planetary gears. The multiple teeth of each planetary gear mesh simultaneously during operation to increase the transmittable torque. The gears are case hardened and ground, and the ratios of the planetary gears are integers. They were first functionally described by Leonardo da Vinci in 1490. Today, the CFHK Series is a favorite among automotive engineers and manufacturers.
The CH Series offers high accuracy with a compact design and case hardened, hypoid, and helical gearing. These gearboxes are also available in the CFXR series, with low backlash and friction. These planetary gearboxes are designed to provide high torque and high precision in a variety of applications. In addition, the CFXR series features 100% helical gearing and low backlash.
The CFHK Series features a sun gear that drives the next stage. These gears can be put in series or serially in the same housing. In some cases, the output shaft of the first stage becomes the input shaft of the second stage. In addition, ring gears are also used as structural parts of smaller gearboxes. An example of a planetary gearbox is the pencil sharpener mechanism. The pencil is placed on an axis that is set on a sun gear. The sun gear drives the next planet stage.
A planetary gear unit’s gear ratio is determined by the number of teeth in the sun gear and ring gear. The smaller the sun gear, the smaller the ratio between the sun gear and planet gears. The largest gear ratio in a planetary gear unit is 10:1. A higher number of teeth increases the transmission ratio. In order to maximize torque, the planetary gears must be rearranged. A smaller sun gear will have higher torque than a large ring gear.

CFX Series

The HPN Harmonic Planetary(r) Series planetary gearboxes offer a low-cost solution with high-performance and high-reliability. This modular design is easy to install and requires very little maintenance. Its planetary design and full complement of needle rollers allow for extended life and quiet operation. In addition, the HPN Harmonic Planetary(r) Series is available in a range of sizes.
The compact size and high-speed design of planetary gearboxes results in excellent heat dissipation. However, high-speed or sustained performance applications may require lubricants. A planetary gearbox will have smaller minimum steps to minimize noise and vibration. Planetary gears will give you the highest level of efficiency while minimizing noise. As a result, they can provide high-quality 3D prints.
A planetary gear train is composed of a ring gear and planet gears, each supported by a carrier. A ring gear is pink, while the sun gear is red. The sun gear and carrier rotate around each other at a 45-degree angle. This is also known as an epicyclic gear. Planetary gearboxes are often found in space-constrained applications. The CFX Series features a compact design and excellent performance.
The CFX Series features a robust design that is easy to install. Its compact size makes installation of planetary gearboxes easier and faster. They are available in three different configurations for continuous, intermittent, and counter-clockwise operation. The CFX Series offers the perfect solution for your accelerating needs. They’re a great solution for any automotive or industrial application. You can easily configure the CFX Series to meet your specific requirements.

CAP Series

The Candy Controls CAP Series is a new generation of compact, precision planetary gearboxes that combine high torques with low backlash and exceptional wear resistance. This rotary flange planetary gearbox is ideal for a variety of industrial, mining and marine applications. Its modular construction enables users to easily mount different stages, hydraulic or electric motors, and different types of gears. Its CPH Series features an extremely rigid alloy steel housing, carburized gears, and induction hardened gears.
The CAP Series utilizes multiple planetary gears for high torque transmission. The number of planetary gears is not fixed, but most planetary gearboxes utilize at least three. The larger the number of planetary gears, the higher the transmittable torque. A planetary gearbox is composed of multiple planetary gears with a meshing action that occurs simultaneously during operation. The result is a higher efficiency and a smoother, quieter operation than a conventional gearbox.
The VersaPlanetary range features modular design for easy installation. This system includes mounting plates for typical FIRST (r) Robotics Competition motors. The mounting plates are designed to fit each motor. These planetary gearboxes are compatible with various types of motors, from small electric motors to large, heavy duty ones. They are also compatible with a variety of mounting systems, including CIM motors.
planetarygearbox

CAPK Series

The CZPT APK Series is a high precision, rotary flange style planetary gearbox. Its case hardened and ground gears are designed to provide excellent wear resistance, low backlash, and excellent precision. The CAPK Series offers high axial and moment load capacities in a compact housing. CZPT is the world leader in the production of planetary gearboxes. The CAPK Series features an array of high-quality, innovative features.
CZPT SMART Lubrication technology is used to keep the gears well-lubricated and reduce noise and vibration. The planetary gearbox’s 3-gear design is ideal for DIY CNC robotics. This series has a long history of quality, and CZPT uses only the best components. The CZPT 3:1 High Precision Planetary Gearbox is an excellent choice for CNC Robotics and other applications.
A multi-stage planetary gearbox combines individual ratios for a greater number of ratios. Additional planetary gears increase the transmittable torque. The direction of the output and drive shaft are always identical. The CAPK Series features a high-quality, durable construction. They are made from stainless steel and offer a long-term warranty. They are the best choice for industrial and commercial applications. While planetary gears are more expensive, they are highly efficient.

CFH Series

The Candy CFH Series planetary gearboxes offer the benefits of a modular design and a low backlash. They offer a variety of size options and excellent durability. This planetary gearbox is compact and wear resistant. The CFH Series planetary gearbox has a carburized, induction hardened gears and a rigid alloy steel housing. Its low backlash and precision make it an excellent choice for industrial applications.
The CFH Series planetary gearbox is a highly efficient, high-speed helical gear. The compact design of this gearbox results in high heat dissipation and low mass inertia. Planet carrier bearings experience significant lateral forces from the transmission of torque. As a result, radial and axial forces oppose each other. The result is that the torque is distributed over three gears, reducing noise, vibration, and wear.
The planetary gearbox has three main components: a sun gear (also known as the input gear), a ring gear, and two planet gears. These are connected by a carrier that rotates about a 45-degree clockwise axis. The CFH Series of gears is available in triple and double stages. They can also be used in electric motors. As a result, the CFH Series is highly versatile.
The CFH Series of planetary gearboxes can be found in all kinds of applications, including automotive transmissions. Their compact design and high-performance performance make them a popular choice for space-constrained applications. This gearbox has several benefits and is a great alternative to a conventional helical gearbox. These gearboxes are highly effective for reducing torque and speed, and are compact enough to fit in most applications.
planetarygearbox

CZPT

If you need a high-quality planetary gearbox, the CZPT Planetary Series is the right choice. This Italian company designs and manufactures gearboxes in its San Polo d’Enza, Italy, facility with 11 branch offices and three production facilities. The company is attempting to replicate the success of the Italian Super Car industry, which has gained global recognition. The company provides a range of gearboxes for use in heavy industry, agriculture, offshore, aerial and marine work.
With over 40 years of experience, CZPT manufactures a wide range of high-quality gearboxes. From bevel-helical units to Helical units, wheel gears and negative brakes, the company has been manufacturing quality components for many industries. CZPT is a trusted Australian distributor of CZPT gear components. The company is dedicated to providing the best planetary gears for every industry.
If your CZPT Planetary gearbox is malfunctioning, you can have it repaired quickly and easily. The company uses quality materials and a variety of sizes and output ratios to cater to the most demanding applications. In addition, you can customize your gearbox to suit your specific needs. CZPT Planetary Gearboxes are highly versatile and customizable, offering infinite scalability.

China manufacturer CZPT Planetary Harmonic Drive Cycloidal Gear Reducer Variable Speed Gearbox   planetary gearbox applicationChina manufacturer CZPT Planetary Harmonic Drive Cycloidal Gear Reducer Variable Speed Gearbox   planetary gearbox application
editor by CX 2023-07-11

China best China Gear Box Reducers Robot Arm Gearbox With Compact Structure Small Size Series Harmonic with Good quality

Warranty: 1year
Applicable Industries: Manufacturing Plant, Machinery Repair Shops, Retail, Wholesale
Weight (KG): 0.22 KG
Customized support: OEM, ODM
Gearing Arrangement: Electromagnetic coupling and mechanical connection
Output Torque: 3.7-24 NM
Input Speed: 2000-4000 r/min
Output Speed: 12.5-80rpm/min, GBM3506H-130T DC brushless gimbal motor 12.5-80rpm/min
Material: Iron casting
Color: Silver gray
Mounting Position: Horizontal (foot Mounted)
Speed ratio: 50
Arc: ≤30
Quality: 100% Tested
Life Span: 10000 hours
Noise: <50dB
Certification: CE, CCC, ISO
Packaging Details: Carton + foam, a large number, will be packed into wooden cases.

ModelSpeed ratioEnter the rated torque at 2000r/minAllowed CZPT torque at start stopThe allowable maximum of the average load torqueNmkgfmNmkgfmNmkgfm14503.70.38121.24.80.49804.20.43161.65.90.61005.40.55191.97.70.791750111.1232.3181.980141.4300.3212.1100161.6373.8272.82050171.7394242.485712.1464.7303.115712.9575.8343.5 ModelMaximum torque is allowed in an instantAllow the maximum speed to be enteredAverage input speed is allowedBack gapdesign lifeNmkgfmr/hinr/hinArcSecHour14242.4850 0571 0≤ ChiHai Motor CHW-GW4058-3162 DC12V 24V Powerful Turbo Worm Geared Motor Type-D Shaft High Power Reversed Low Speed Worm motor 30700571.1353.617484.9730 0571 0≤3571000585.9717.220697650 0571 0≤357100571.8959.7 More Products About Us Certifications Factory Show Transportation & Packaging FAQ Q: What should I provide when I choose gearbox/speed reducer?A: The best way is to provide the motor drawing with parameter. Our engineer will check and recommend the most suitable gearbox model for your refer. Or you can also provide below specification as well:1) Type, model and torque.2) Ratio or output speed3) Working condition and connection method4) Quality and installed machine name5) Input mode and input speed6) Motor brand model or flange and motor shaft size

Types of Vehicle Gearboxes

In a vehicle, there are many types of gearboxes available. There are planetary gearboxes, Coaxial helical gearboxes, and skew bevel helical gearboxes, among others. In this article, we’ll cover all of them and help you determine which type of gearbox would be right for your vehicle. Also, we’ll discuss how each differs from the others.
gearbox

planetary gearbox

A planetary gearbox is composed of three main components: a sun gear, an input bevel gear, and an output shaft. A planetary gearbox can have different output torques and ratios. The basic model of a planetary gearbox is highly efficient and transmits 97% of the power input. There are several kinds of planetary gearboxes, depending on the type of operation. In general, there are three types: the simple, the intermediate, and the complex.
The price of a planetary gearbox can vary a lot, and it’s important to know what you’ll need. Different manufacturers produce different planetary gearboxes, so check with a manufacturer to see what they have available. Make sure to check the quality of the planetary gearbox before making a final purchase. In addition, be sure to compare the prices and the availability of a particular product. A quality planetary gearbox will provide years of trouble-free operation and will not break your bank.
Planetary gears feature an integer number of teeth. Each planet has teeth that must mesh with its ring or sun. The number of planets, ring, and tooth count of each gear determine whether the teeth mesh. Some planets have fewer teeth than others, so they mesh better than others. However, compound planets can be more flexible and achieve higher reduction ratios. If you’re looking for a planetary gearbox for your next project, consider getting in touch with a manufacturer who specializes in this technology.
When it comes to construction, a planetary gearbox is no exception. It’s extremely important to choose the right planetary gear for your application, because an imbalance in the planet gear can cause increased wear and failure. Moreover, the compact size of a planetary gear ensures maximum heat dissipation. However, a planetary gear box may require cooling in some applications. A planetary gearbox will make your life easier, and it will give you years of trouble-free operation.

Straight bevel helical gearbox

The Straight bevel helical gearbox has a number of advantages, but it has a relatively short manufacturing process. Its most popular application is in the automotive industry, where it is used in many types of vehicles. Other applications include heavy and light equipment and the aviation and marine industries. Below is a brief introduction to this gearbox type. Read on to learn about its benefits. This type of gearbox is one of the easiest to manufacture.
The spiral bevel gear has larger teeth than straight bevel gears, resulting in a smoother, quieter rotation. It can handle high-speed heavy loads with less vibration. Spiral bevel gears are classified by their tooth form and cutting method. Straight bevel gears are easier to design and manufacture, but spiral bevel gears are more expensive. Both designs are suitable for high-speed, heavy-load operations, and general manufacturing applications.
In addition to being easy to install, the modular bevel gears have many advantages. They have an exceptionally high degree of interchangeability and feature the highest standards of component integrity. They can also be tailored to meet your specific requirements. The advantages of this gearbox type include high precision, optimum performance, and low noise. And because they are modular, they can be produced in a variety of finishes. These include stainless steel, titanium, and bronze.
Straight bevel helical gearbox manufacturers are committed to a high degree of precision in their designs. The radii, torques, and tooth profiles of straight bevel gears are more precisely measured than those of cylindrical bevel gears. The same calculations are used for all traditional bevel gear generators. This ensures that your 5-axis milled bevel gear sets have the same calculations and layout.
gearbox

Coaxial helical gearbox

The Coaxial helical gearbox is a highly efficient transmission system that is well suited for light-duty applications. Compared to spur-type gearboxes, the real pitch of a Coaxial helical gearbox is low at all helix angles. This is because the coaxial type has the same number of teeth and center gap as the spur gearbox. Coaxial helical gearboxes also have a smaller footprint and are compact.
Several nations have implemented lockdown regulations for Industrial Gearbox trade, threatening the global economy. Several factors have been implicated in COVID-19, including supply chain, market, and financial markets. Experts are monitoring the situation globally and project remunerative prospects for gearbox manufacturers after the crisis. This report depicts the latest scenario and offers a comprehensive analysis of COVID-19’s impact on the entire industry.
This Coaxial helical gearbox features a compact structure and high precision gear. Its three-stage design combines two-stage gears with a single-stage gear, forging high-quality alloy steel for high precision and durability. The gears are serially-designed for easy interchangeability. They are also available in high-frequency heat-treated steel. A Coaxial helical gearbox is the perfect solution for many applications.
Coaxial helical gearboxes have the added benefit of using cylindrical gears instead of shafts. They operate quietly, and have more surface area to interact with. Their fixed angles make them suitable for heavy-duty applications, like in conveyors, coolers, and grinders. Compared to other gearbox types, Helical gearboxes have higher power-carrying capacity. Listed below are the benefits of a Coaxial Helical Gearbox

Skew bevel helical gearbox

A Skew bevel helical gear box is a common type of industrial gearbox. These gearboxes are rigid and compact and can be used in a variety of applications. They are commonly used in heavy-duty applications such as grinding mills, conveyors, and coolers. They are used in many applications to provide rotary motions between non-parallel shafts. They also have the added benefit of high-efficiency in a variety of industries.
Skew bevel helical gear boxes are suitable for heavy loads and are monolithic in construction. This type of gearbox combines the benefits of bevel and helical gears for right-angle torque, which makes it a popular choice for heavy-duty applications. In addition to being a robust and reliable gearbox, these gearboxes are highly customizable and can meet almost any industrial need.
To maximize the efficiency of bevel gears, FE-based tooth contact analysis is used to develop a sophisticated geometry optimization algorithm. The software also allows users to define optimal flank topography by introducing application-specific weightings for specific load levels. With this data, a manufacturing simulation is conducted to determine the best variant. A robust variant combines the benefits of efficiency, load-carrying capacity, and low excitation behavior.
The helical gear can be angled at 90 degrees. This is similar to a spur gear but produces less noise. It can achieve a nine-to-one speed reduction with one stage. However, a helical gear requires a larger driver gear for higher reductions. This gearbox is suitable for speeds from 1:1 to three times. They are often used in the manufacture of motors and generators.
gearbox

Extruder helical gearbox

An extruder helical gearbox is one of the most common industrial gears. It is compact in size and low-power consuming, making it ideal for heavy-duty applications. Extruder helical gearboxes are suitable for a variety of industrial applications, including cement, plastics, rubber, conveyors, and coolers. In addition to its use in plastics and rubber manufacturing, this gearbox is also useful in other low-power applications such as crushers, coolers, and conveyors.
CZPT SG series Extruder Helical Gearboxes are available in Single Screw and Twin Screw Variations. These gears feature a compact design, high power density, and long service life. Axial bearing housing and thrust bearings are mounted on the input shafts. Extruder helical gearboxes can be installed in various positions, including horizontal, vertical, and inclined.
Helicoidal gears are often produced in a modular manner. This design provides multiple benefits, including engineering and performance advantages, modular production, and the highest level of component integrity. A single helical gearbox can be assembled into a larger gearbox if needed, but modular production ensures consistent performance and economy. This modular design is also cost-effective. It is a versatile and reliable solution for a wide range of applications.
In addition to its efficiencies, Extruder helical gearboxes also have a low noise profile. They have no squeal sounds, and they are silent when running. They can transfer more power than conventional gearboxes. This type of gear has been used in the manufacturing of high-quality plastic products for years. They are often used for applications in automotive transmissions. Aside from being quiet, helical gears have higher contact levels and lower vibration.

China best China Gear Box Reducers Robot Arm Gearbox With Compact Structure Small Size Series Harmonic  with Good qualityChina best China Gear Box Reducers Robot Arm Gearbox With Compact Structure Small Size Series Harmonic  with Good quality