HS Code | Product Description | Official Doc | Tariff Rate | Origin | Destination | Effective Date |
---|---|---|---|---|---|---|
8483405050 | Transmission shafts (including camshafts and crankshafts) and cranks; bearing housings, housed bearings and plain shaft bearings; gears and gearing; ball or roller screws; gear boxes and other speed changers, including torque converters; flywheels and pulleys, including pulley blocks; clutches and shaft couplings (including universal joints); parts thereof: Gears and gearing, other than toothed wheels, chain sprockets and other transmission elements entered separately; ball or roller screws; gear boxes and other speed changers, including torque converters: Gear boxes and other speed changers: Fixed ratio speed changers, multiple and variable ratio speed changers each ratio of which is selected by manual manipulation: Other Other | Doc | 57.5% | CN | US | 2025-05-12 |
8708403000 | Parts and accessories of the motor vehicles of headings 8701 to 8705: Gear boxes and parts thereof: Gear boxes: For tractors suitable for agricultural use | Doc | 55.0% | CN | US | 2025-05-12 |
8708405000 | Parts and accessories of the motor vehicles of headings 8701 to 8705: Gear boxes and parts thereof: Gear boxes: For other vehicles | Doc | 57.5% | CN | US | 2025-05-12 |
8714995000 | Parts and accessories of vehicles of headings 8711 to 8713: Other: Other: Derailleurs and parts thereof | Doc | 37.5% | CN | US | 2025-05-12 |
7326908688 | Other articles of iron or steel: Other: Other: Other: Other Other | Doc | 82.9% | CN | US | 2025-05-12 |
7326908688 | Other articles of iron or steel: Other: Other: Other: Other Other | Doc | 82.9% | CN | US | 2025-05-12 |
7325995000 | Other cast articles of iron or steel: Other: Other: Other | Doc | 82.9% | CN | US | 2025-05-12 |
7325991000 | Other cast articles of iron or steel: Other: Other: Of cast iron | Doc | 80.0% | CN | US | 2025-05-12 |
Gearbox
A gearbox (also known as a transmission) is a system of gears used to modify torque and speed from a rotating power source to another device. It is a crucial component in many mechanical systems, enabling efficient power transfer and adaptation to varying load requirements.
Material:
- Gears: Typically constructed from hardened steel alloys (e.g., alloy steels like 4140 or 8620) for strength and durability. Cast iron, brass, and plastics are used in lower-torque applications.
- Housing: Often made from cast iron, aluminum alloys, or steel for rigidity and protection.
- Shafts: Generally high-strength steel alloys.
- Bearings: Rolling-element bearings (ball or roller bearings) made of bearing steel are common, reducing friction.
- Lubricants: Gear oil, specifically formulated to withstand high pressures and shear forces, is essential for reducing friction and wear.
Purpose:
The primary purposes of a gearbox are:
- Torque Multiplication: Increasing the output torque while reducing the output speed. This is essential for applications requiring high force, such as lifting heavy loads or overcoming significant resistance.
- Speed Reduction: Decreasing the output speed while increasing the output torque.
- Speed Increase: Increasing the output speed while decreasing the output torque (less common, but used in some applications).
- Direction of Rotation Change: Altering the direction of the output shaft’s rotation.
- Power Transmission: Efficiently transferring mechanical power from the power source to the driven equipment.
Function:
A gearbox functions by utilizing gears of different sizes and numbers of teeth. The ratio between the number of teeth on the input and output gears determines the gear ratio.
- Gear Ratio: The gear ratio (Nout/Nin) dictates the relationship between the input and output speeds and torques. A higher gear ratio results in higher torque and lower speed, and vice versa.
- Gear Meshing: Gears are precisely cut to ensure smooth and efficient meshing, minimizing friction and wear.
- Shaft Support: Shafts support the gears and transmit the rotational force.
- Lubrication System: A lubrication system ensures adequate oil supply to all gear surfaces, reducing friction and heat.
Usage Scenarios:
Gearboxes are found in a wide range of applications, including:
- Automotive Vehicles: Transmitting power from the engine to the wheels, providing different gear ratios for acceleration, cruising, and hill climbing.
- Industrial Machinery: Powering pumps, compressors, conveyors, and other heavy-duty equipment.
- Wind Turbines: Increasing the rotational speed of the generator to match the grid frequency.
- Robotics: Providing precise control of motor speed and torque.
- Construction Equipment: Powering excavators, cranes, and bulldozers.
- Aircraft: Reducing engine speed and increasing torque for propeller or rotor drive.
- Household Appliances: Washing machines, blenders, and drills often utilize gearboxes.
Common Types:
- Spur Gearbox: Utilizes straight-cut gears. Simple, cost-effective, but can be noisy at high speeds.
- Helical Gearbox: Utilizes gears with angled teeth. Quieter and smoother operation than spur gears, but generates axial thrust.
- Bevel Gearbox: Utilizes conical gears to transmit power between shafts at an angle.
- Worm Gearbox: Utilizes a worm and worm wheel. High gear ratios, self-locking capability, but lower efficiency.
- Planetary Gearbox: Utilizes a sun gear, planet gears, and a ring gear. Compact, high torque capacity, and efficient.
- Harmonic Gearbox: Utilizes a flexspline, wave generator, and circular spline. High gear ratio, compact size, and zero backlash, commonly used in robotics and precision applications.
- Strain Wave Gearbox: Similar to harmonic gearboxes.
- Cycloidal Gearbox: Utilizes cycloidal disks and rollers. High torque capacity, high efficiency, and compact size.
The declared goods are “gearbox,” which is a mechanical component used to transfer power and change speed or torque. They are found in a variety of applications, including automobiles, tractors, and industrial machinery.
The following HS codes are relevant to “gearbox” based on the provided reference material:
- 8483405050: This HS code falls under Chapter 84 (Nuclear reactors, boilers, machinery and mechanical appliances; parts thereof) and specifically covers transmission shafts (including camshafts and crankshafts) and cranks; bearing housings, housed bearings and plain shaft bearings; gears and gearing; ball or roller screws; gear boxes and other speed changers, including torque converters; flywheels and pulleys, including pulley blocks; clutches and shaft couplings (including universal joints); parts thereof. The subheading 405050 specifically refers to gear boxes and other speed changers: Fixed ratio speed changers, multiple and variable ratio speed changers each ratio of which is selected by manual manipulation. The total tax rate is 57.5%, comprised of a 2.5% base tariff, a 25.0% additional tariff, and a 30.0% additional tariff effective April 2, 2025.
- 8708403000: This HS code falls under Chapter 87 (Vehicles other than railway or tramway rolling-stock, and parts and accessories thereof) and specifically covers parts and accessories of the motor vehicles of headings 8701 to 8705: Gear boxes and parts thereof: Gear boxes: For tractors suitable for agricultural use. The total tax rate is 55.0%, comprised of a 0.0% base tariff and a 25.0% additional tariff, increasing to 30.0% effective April 2, 2025.
- 8708405000: This HS code falls under Chapter 87 (Vehicles other than railway or tramway rolling-stock, and parts and accessories thereof) and specifically covers parts and accessories of the motor vehicles of headings 8701 to 8705: Gear boxes and parts thereof: Gear boxes: For other vehicles. The total tax rate is 57.5%, comprised of a 2.5% base tariff and a 25.0% additional tariff, increasing to 30.0% effective April 2, 2025.
Important Note: When declaring a gearbox, it is crucial to determine its intended application. If the gearbox is specifically designed for tractors suitable for agricultural use, HS code 8708403000 should be used. Otherwise, if it is for other vehicles, HS code 8708405000 should be used. If the gearbox is not related to motor vehicles, HS code 8483405050 should be considered.