China Custom Custom ∅ 0.6-0.8 NDT Grade Hot Steel Forging Sun & Planet Gear, Shaft, Planet Carrier Blank for Planetary Gearboxes with Good quality

Product Description

Forged Parts for Planetary Gearboxes

Planetary gears, also known as epicyclic gears, play a crucial role in modern engineering; these gears are at the heart of various applications. Forged steel components are critical for planetary gearboxes due to their high torque density, operational efficiency, and durability.

Typical forged steel components that make up a planetary gearbox:

Sun Gear (Central Gear): The sun gear is positioned at the center of the planetary gearbox. It drives the surrounding planetary gears, transmitting power from the input shaft to the planet gears.

Multiple Planet Gears: The primary function of planet gears is to transmit torque and adjust the speed of rotation or torque between the input and output shafts. These gears orbit around the sun gear.

Ring Gear (Outer Gear): The ring gear rotates in the same direction as the sun gear, providing a reverse direction of motion. It encircles the planet gears and completes the gear system.

Planet Carrier: The planet carrier holds the planet gears in place. It connects the centers of the sun gear and the ring gear, ensuring smooth rolling without slipping during operation.


In summary, forged steel parts for planetary gears are essential for achieving reliable and efficient gear systems across various industries. They enable smooth power transmission and precise motion control. Whether in wind power applications, industrial machinery, or aerospace systems, these robust components ensure optimal performance and longevity.

Product Sample Drawings

Customized Solutions

At Tiangong Forging, our modular process allows us to design solutions various industrial application requiring free-forged and open-die-forged parts. Our modularity means flexibility, wide choice, faster delivery and, above all, competitiveness.
All our products and production processes are designed to ensure exceptional, reliable and long-lasting unigue mechanical properties, thereby reducing operating costs and extending service life.
Our products can meet rigorous quality standards such as ∅0.6-0.8 Ultrasonic Testing requirement.

Steel Materials

Tiangong Forging supplies a variety of semi-finished forged steel products, with the main materials being nickel-molybdenum steel, alloy steel, die steel, stainless steel and carbon steel. In addition to general steel grades, we can also prepare the required steel according to other national specifications or specified alloy compositions requested by customers.

General Steel Grade

Carbon Steel 20#
Alloy Steel Q345A
Nickel Alloy Steel 18CrNiMo7-6


Product Parameters

The maximum gear and wheel forging diameter/weight is 1.9m / 9 ton. The maximum production shaft forging length/weight is 12m / 15 ton.

We can supply products in 3 different states according to customer requirements:
– Forged blank, 
– Rough machined
– Semi-finishing machined 

Heat Treatment Options: 
We offer multiple heat treatment options to achieve the desired mechanical properties. From hardness to toughness, we tailor the treatment to meet customers specific requirements.

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Processing Object: Metal
Molding Style: Forging
Molding Technics: Free and Open Dieforging


Customized Request

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Currency: US$
Return&refunds: You can apply for a refund up to 30 days after receipt of the products.

epicylic gear

Can planetary gears be used in automotive applications?

Planetary gears are widely used in various automotive applications due to their numerous advantages. Let’s explore how planetary gears can be utilized in the automotive industry:

  • Automatic Transmissions:

One of the primary applications of planetary gears in automobiles is in automatic transmissions. Automatic transmissions use a combination of planetary gear sets to achieve different gear ratios, allowing for smooth and efficient shifting between gears. The compact size and high torque capacity of planetary gears make them well-suited for this purpose, providing reliable and efficient power transmission in vehicles.

  • Four-Wheel Drive Systems:

Planetary gears are also employed in four-wheel drive systems, where they help distribute power between the front and rear wheels. By utilizing planetary gear arrangements, the torque can be split between the front and rear axles, providing improved traction and stability on various road conditions. This allows vehicles to have enhanced off-road capabilities and better performance in challenging driving situations.

  • Hybrid and Electric Vehicles:

Planetary gears play a crucial role in hybrid and electric vehicle powertrains. In these vehicles, planetary gear sets are often used to combine the power from the internal combustion engine and the electric motor. The gear arrangement allows for seamless transitions between different power sources, enabling efficient energy management and optimized performance.

  • Start-Stop Systems:

Start-stop systems, which automatically shut off the engine when the vehicle is stationary and restart it when needed, often incorporate planetary gears. These gears help engage and disengage the engine from the drivetrain smoothly, ensuring a quick and seamless transition between the engine’s off and on states. Planetary gears contribute to the overall efficiency and reliability of start-stop systems.

  • Power Steering:

Some power steering systems in automobiles utilize planetary gears to provide assistance in steering. These gears help amplify the driver’s input torque, making steering easier and more responsive. The compact size and high torque capacity of planetary gears make them suitable for power steering applications.

In summary, planetary gears find extensive use in automotive applications, including automatic transmissions, four-wheel drive systems, hybrid and electric vehicle powertrains, start-stop systems, and power steering. Their compact size, high torque capacity, and ability to achieve multiple gear ratios make them well-suited for these applications, providing efficient power transmission, improved performance, and enhanced driving experience in vehicles.

epicylic gear

Can you explain the process of gear shifting in planetary gear systems?

Gear shifting in planetary gear systems involves changing the gear ratio by engaging or disengaging specific components of the gear set. Let’s explore the process of gear shifting in more detail:

  • Clutching and Braking:

The gear shifting process in planetary gear systems primarily relies on clutching and braking mechanisms. These mechanisms selectively connect or disconnect various gears within the system to achieve the desired gear ratio. Here are the key steps involved:

  • Clutch Engagement:

To shift to a higher gear ratio, the clutch associated with the gear component that needs to be engaged is activated. The clutch connects the rotating member, such as the sun gear, planet carrier, or ring gear, to the stationary member, allowing torque transmission. This engagement results in a change in the gear ratio, leading to higher speed or torque output depending on the specific gear set configuration.

  • Brake Application:

On the other hand, to shift to a lower gear ratio, a brake associated with the gear component that needs to be disengaged is applied. The brake immobilizes or slows down the rotation of the selected gear element, preventing it from transmitting torque. By selectively braking certain components, the gear ratio is altered, resulting in a lower speed or higher torque output.

  • Sequential Shifting:

In some planetary gear systems, gear shifting is performed sequentially. This means that one gear component is engaged or disengaged at a time, gradually transitioning from one gear ratio to another. Sequential shifting allows for smooth and controlled gear changes, minimizing the stress on the transmission components and ensuring seamless power transmission.

  • Electronic Control:

In modern applications, gear shifting in planetary gear systems is often electronically controlled. Electronic control systems utilize sensors, actuators, and a control unit to monitor various parameters such as vehicle speed, engine load, and driver input. Based on these inputs, the control unit determines the optimal gear shift points and actuates the clutches and brakes accordingly. Electronic control enhances the efficiency, precision, and automation of the gear shifting process.

In summary, gear shifting in planetary gear systems involves the engagement and disengagement of clutches and brakes to alter the gear ratio. By selectively connecting or disconnecting specific gear components, the speed and torque output can be adjusted. Sequential shifting and electronic control systems further enhance the gear shifting process, providing smooth and efficient operation in various applications, including automotive transmissions and industrial machinery.

epicylic gear

Can you explain the unique design and structure of planetary gears?

Planetary gears possess a unique design and structure that sets them apart from other gear systems. Let’s explore the distinctive features of the design and structure of planetary gears:

  • Components:

A planetary gear system consists of three main components: the sun gear, planet gears, and a ring gear. The sun gear is located at the center and is typically driven by an input source such as a motor or engine. The planet gears are gears that surround the sun gear and are connected to a carrier or arm. The ring gear is the outermost gear and meshes with the planet gears.

  • Internal Gear Meshing:

One of the distinguishing features of planetary gears is their internal gear meshing. Unlike other gear systems where the gears mesh externally, the teeth of the sun gear, planet gears, and ring gear are located on the inside surfaces. This arrangement allows for a compact and space-efficient design.

  • Orbiting Motion:

In planetary gears, the planet gears exhibit both rotational and orbital motion. While they rotate on their own axes, they also orbit around the sun gear. This combination of rotational and orbital movement enables the gear system to achieve different gear ratios and torque transmission.

  • Central Sun Gear:

The presence of a central sun gear is another characteristic of planetary gears. The sun gear is positioned at the center of the gear arrangement and serves as the primary driver for the overall gear operation. It receives the input power and transmits it to the planet gears.

  • Versatile Gear Ratios:

Planetary gears are capable of achieving a wide range of gear ratios. The gear ratio is determined by the relative sizes of the gears and the number of teeth on each gear. By varying the number of teeth on the sun gear, planet gears, and ring gear, different gear ratios can be obtained, providing versatility in speed reduction or amplification.

  • Load Distribution:

The arrangement of multiple planet gears in a planetary gear system helps distribute the load among the gears. This load distribution results in efficient torque transmission and enhanced durability. It also contributes to shock absorption and noise reduction during gear operation.

  • Compact Size:

Planetary gears are known for their compact size. The internal gear meshing and the integration of multiple gear sets within a single system contribute to their space-saving design. The compactness of planetary gears is advantageous in applications where size and weight restrictions are critical.

  • Wide Range of Applications:

Due to their unique design and structural characteristics, planetary gears find applications in various industries and mechanical systems. They are commonly used in automotive transmissions, robotics, aerospace systems, industrial machinery, and more. The ability to achieve different gear ratios, transmit torque efficiently, and operate in compact spaces makes planetary gears versatile in transmitting power.

In summary, the unique design and structure of planetary gears include components such as the sun gear, planet gears, and ring gear, internal gear meshing, orbiting motion of the planet gears, a central sun gear, versatile gear ratios, load distribution, compact size, and wide-ranging applications. These features contribute to the efficiency, versatility, and space-saving nature of planetary gears, making them suitable for various mechanical systems.

China Custom Custom ∅ 0.6-0.8 NDT Grade Hot Steel Forging Sun & Planet Gear, Shaft, Planet Carrier Blank for Planetary Gearboxes with Good qualityChina Custom Custom ∅ 0.6-0.8 NDT Grade Hot Steel Forging Sun & Planet Gear, Shaft, Planet Carrier Blank for Planetary Gearboxes with Good quality
editor by Dream 2024-05-16