Zhejiang Sankai Mechanical and Electrical Co., Ltd

Worm Gearbox

What is Worm Gearbox



A worm gearbox utilises an assortment of shafts, bearings, toothed wheels and worm gears to create motion. Worm gearboxes are required in numerous mechanical procedures and engines. They can also modify the input rotational movement by 90 degrees to the output. When a worm gear spins, it allows the toothed wheel placed inside to move. Due to this improvement, worm gearbox manufacturers can now produce worm gearboxes that can change rotational direction, amongst other things. However, worm gearboxes require higher levels of lubrication due to their heightened friction rate.


Advantages of Worm Gearbox


Worm gearboxes are designed to be one of the most compact gearboxes in the market. It achieves this level of compactness as the worm gear can change drive direction by 90 degrees. Worm gearboxes are perfect for applications requiring high torque but limited speed.

Increase Torque

This gearbox increases the torque to a significant extent in the mechanical system. Due to the unique worm gear design, they mesh with the worm wheel and produce high torque outputs.



Quiet Operation

Worm gearbox manufacturers create worm gearboxes to be one of the quietest gearboxes in the industry. This is perfect for applications where noise levels need to be maintained strictly. Although you need to ensure they are not worn out, incorrectly mounted, or not well-lubricated, as that can make this gearbox noisy.

Decrease the System Speed

Worm gearboxes can also be employed to decrease the mechanical system’s speed. They obtain this by containing a series of high-ratio gears. It is an excellent benefit if you intend to adjust the output speed without modifying the motor or engine arrangement. A worm gearbox is easy to bolt on the end of the drive to make this feasible.

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Our Factory
Zhejiang Sankai Machine and Electric Co.,Ltd is an integrative and professional manufacturer of power transmission device, which specialize in scientific research, production and marketing.


Adopting advanced detecting equipment and means, company establishes a quality control system that is in accordance with 1S0900 I: 2015. Products are sold all over the country, exporting to Southeast Asia, Europe, America and other regions. Sankai will continue, as we always do, to strive to become a leader of power transmission industry.


Our Products
Our company specialize in High Precision Planetary Gearbox, NMRV series Worm Gearbox, UDL series Stepless Speed Variator, SRC series Helical Gearbox, SKM series Helical-Hypoid Gearbox, Precision Gearbox for Robot Arm and PC Helical Gear Unit.


Quality services
Sincerely Sankai determine to provide service of better quality, in-time and fast reply to our clients. And Sankai is looking forward to cooperating with domestic and foreign friends and grow together with our hard work and professionalism.

Types of Worm Gearbox

Single Reduction Worm Gearbox

This is the most basic type of worm gearbox.
It consists of a single set of worm gear and a worm wheel.
Provides a moderate reduction ratio and is suitable for many industrial applications.


Double Reduction Worm Gearbox

Also known as double-worm gearboxes or multi-stage worm gearboxes.
Consists of two sets of worm gears and worm wheels in series.
Offers a higher reduction ratio than single reduction gearboxes.
Provides increased torque output and is often used in heavy-duty applications.

Right-Angle Worm Gearbox

Designed to transmit motion and power at a 90-degree angle.
Ideal for applications where space constraints or the need for a right-angle drive is essential.
Commonly used in conveyor systems, elevators, and some automotive applications.

Hollow Output Shaft Worm Gearbox

Features a hollow output shaft.
Useful for applications where the driven component needs. To pass through the gearbox, such as in some lifting systems and rotary tables.

How to Choose Worm Gearbox
Types of Worm Gearboxes

Identify the reduction gearbox that fits your requirement after understanding the different types of worm gearboxes. You can find three types of gearboxes - Non-enveloping, single envelope and double envelope. The non-enveloping type does not have concave features. In this type, a contact point is a straight plane that places stress on the gearbox.
In a single envelope, you will find the gear has a concave tooth width. As a result, the worm drives deeper into the gear and increases efficiency. A double envelope, on the other hand, contains a wide gear with a concave tooth width and a worm drive with a concave design. You can check out the Premium Transmission gearboxes by Santram Engineers to get a good understanding of the different types of Worm Gearboxes.

Tooth Spacing

Tooth spacing is an important aspect that you must consider before selecting the reduction gearbox. Tooth spacing has several parameters such as Diametral Pitch, Circular Pitch, Module, Pressure Angle and Lead Angle. Remember that worm drives and worm wheels must have the same pitch and pressure angle to mesh, but may not mesh if the envelope concavity does not match.


Make sure you consider the application of the worm reduction gearbox before you pick out a gearbox. Understand its power, velocity and torque consistency to ensure that the gearbox meets the mechanical requirements. Also, understand the inertia of the gear. Heavier gears could be difficult to stop or reverse.
Understand the precision mechanism of the gearbox. This means you will have to take a closer look at the gear pitch, pressure angle, tooth layout and shaft diameter.
Other factors you need to look at and understand include handedness, mounting requirements, noise limitation, corrosion resistance, temperature exposure, vibration and shock resistance, etc.


Due to the wear and tear that a reduction gearbox has to undergo, the material used for making gearboxes is usually heavy. From cast iron to carbon steel, gearboxes are available in a wide variety of materials. You can find gearboxes in alloy steel, cast steel, carbon steel, cast iron, aluminium, brass, copper, plastic and even wood.
All materials have very specific functions. So to pick out the right material, understand the benefit of each material and pick the one that suits your business requirement best.


The Worm Gearbox Construction
Worm Gear Reduction Gearbox
Double Speed Gear Reducer
Worm Gear Reduction Gearbox
Double Speed Gear Reducer

→ Worm Gear:
The primary driving component is the worm gear. It is a threaded screw-like rod with a helical shape, resembling a spiral or a screw thread. The worm gear is typically mounted on one of the shafts and connected to the input source of rotation.


→ Worm Wheel:
The worm wheel is the driven component and is usually mounted on the second shaft. which positioned at a right angle to the worm gear. The worm wheel is a cylindrical gear with teeth that mesh with the threads of the worm gear. This interaction enables the transfer of motion and torque from the worm gear to the worm wheel.


→ Housing:
The worm gear and worm wheel enclosed within a housing or gearbox casing. The housing provides protection, support, and proper alignment for the internal components. It designed to withstand the forces and stresses generated during operation.


→ Bearings:
Bearings are crucial components that support the shafts on which the worm gear and worm wheel mounted. These bearings reduce friction and allow for smooth rotation of the shafts.


→ Seals:
Seals used to prevent the ingress of contaminants such as dust and moisture into the gearbox. They help maintain the lubrication and protect the internal components.


→ Lubrication System:
To ensure smooth operation and reduce wear and friction. worm gearboxes are typically equipped with a lubrication system. This system provides the necessary lubricant to the gear meshing surfaces.


→ Input and Output Shafts:
The input shaft connected to the worm gear, and the output shaft connected to the worm wheel. These shafts extend beyond the gearbox housing. and provide the means to transmit power to and from the gearbox.


→ Mounting Flanges:
Worm gearboxes often have mounting flanges or brackets. That allow them to be securely attached to the machinery or equipment they are serving.


→ Adjustment Mechanisms:
Some worm gearboxes may include adjustment mechanisms to control backlash. which is the amount of free play or clearance between the worm gear and worm wheel teeth. Adjustments made to optimize the gearbox’s performance.


→ Bearing Caps and Covers:
These components used to secure the bearings. and provide additional protection to the internal components.


Worm Gear Reduction Gearbox


Where Are Worm Gearboxes Used

In conditions where swift stopping is needed- Since back driving is almost an impossible feat to acquire with the worm gear, they have gained popularity in case of devices where stopping needs to be done swiftly and accurately, like lifts and elevators.

When there is a need for noise control- The contact of two different elements in the worm gearbox reduces the noise pollution, making it ideal for spaces where noise needs to be controlled. Various industrial applications make use of the worm gearbox.

When space is a concern- A worm gear is made use of in heavy machinery like large ships in the ocean or trucks barrelling down a deserted highway. Worm gear finds applications in machinery that need to use torque in confined spaces. The unique shape of the worm gear allows vast flexibility and versatility. They are made use of in packaging equipment, conveyors, and generally all small machinery as well.

Where shock loading is a reality- The materials used in the worm gear are soft in nature facilitating easy shock absorption with less damage. This particular feature is extremely useful for rock crushers and heavy-duty machines.


The Right Way to Lubricate Worm Gearboxes


When it comes to lubrication, worm gearboxes have unique requirements due to the sliding action between the worm gear and the worm wheel. The right lubricant can reduce friction and wear, protect against corrosion, and help dissipate heat. However, using the wrong lubricant or applying it incorrectly can lead to accelerated wear, overheating, and even gearbox failure.


Lubrication Challenges
Worm gearboxes face several challenges when it comes to lubrication. One of the most significant challenges is the sliding action between the worm gear and the worm wheel, which can cause the lubricant to break down faster than in other types of gearboxes. The high contact pressure between the two components also requires a lubricant with high film strength to prevent metal-to-metal contact.


Lubrication Solutions
The right lubricant must be selected based on the specific operating conditions and gearbox design to overcome the challenges of lubricating worm gearboxes. Here are some of the factors to consider when choosing the right lubricant.


The Right Base Oil
Base oil is the foundation of any lubricant, and choosing the right base oil for gearboxes is essential. Mineral oils are commonly used as base oils, but synthetic oils may provide better performance in extreme conditions. Synthetic oils offer improved oxidation resistance, higher film strength, and better low-temperature fluidity.


The Right Additives
Additives are used to enhance the performance of the base oil and provide additional benefits. Anti-wear additives can reduce friction and wear between the worm gear and the worm wheel. Anti-oxidation additives can prevent the lubricant from breaking down at high temperatures, while anti-corrosion additives protect against rust and corrosion.


The Right Viscosity
The viscosity of the lubricant is critical in worm gearboxes. The viscosity must be high enough to provide adequate lubrication but not so high that it causes increased friction and wear. Choosing the right viscosity grade depends on the operating conditions, including the gearbox’s temperature, load, and speed.


The Right Oil Level
The oil level in the gearbox must be maintained at the correct level to ensure proper lubrication. Too much oil can cause foaming and overheating, while too little oil can lead to increased friction and wear. The oil level should be checked regularly and topped up if necessary.


The Right Visual Inspections
Visual inspections of the gearbox can help to detect any signs of wear or damage. The teeth of the worm gear and the worm wheel should be checked for signs of wear or pitting, and any damage should be addressed promptly. The oil level and colour should also be checked regularly to ensure the lubricant performs its job.


Crucial Factors to Consider for Worm Gearbox Maintenance


Lubrication is one of the most critical factors in the maintenance of worm gearboxes. It helps to reduce friction and wear between the worm gear and the worm wheel. Proper lubrication can help extend the lifespan of the gearbox and improve its performance. The type of lubricant used should be appropriate for the operating conditions and the gearbox design.


Regular inspection of worm gearboxes is necessary to detect any signs of wear or damage. This can help to identify problems before they become severe and result in costly downtime. The inspection should include checking the teeth of the worm gear and the worm wheel, as well as the bearings and seals. Any signs of wear or damage should be addressed promptly to prevent further damage.

Temperature Monitoring

Worm gearboxes generate heat during operation. Excessive heat can cause the lubricant to break down, leading to increased friction and wear. It is essential to monitor the temperature of the gearbox regularly and ensure it remains within the recommended operating range. If the temperature exceeds the recommended range, the gearbox may need to be shut down until the cause of the problem is identified and addressed.


Proper cleaning of worm gearboxes is critical to prevent the buildup of dirt and debris, which can cause increased friction and wear. The gearbox should be cleaned regularly using appropriate cleaning agents and techniques. Care should be taken not to damage any gearbox components during cleaning.

Proper Storage

Proper storage of worm gearboxes is crucial when they are not in use. They should be stored in a dry, cool, and clean environment to prevent corrosion and other forms of damage. Before storing the gearbox, it should be cleaned, inspected, and properly lubricated.

Proper Installation

Proper installation of worm gearboxes is essential to ensure optimal performance and longevity. The gearbox should be installed in accordance with the manufacturer’s recommendations, using appropriate tools and techniques. Care should be taken not to damage any components during installation.



Q: How does a worm gearbox work?

A: Basically, a worm gear is a screw butted up against what looks like a standard spur gear with slightly angled and curved teeth. It changes the rotational movement by 90 degrees, and the plane of movement also changes due to the position of the worm on the worm wheel (or simply "the wheel").

Q: Why is it called a worm gear?

A: A worm drive is a gear arrangement in which a worm (which is a gear in the form of a screw) meshes with a worm wheel (which is similar in appearance to a spur gear). The two elements are also called the worm screw and worm gear.

Q: What is a worm reduction gearbox used for?

A: Worm Gear reducers are utilized in power transmission applications requiring high ratio speed reduction in a limited space. The gears are used on right angle, non-intersecting shafts. When properly aligned, worms and worm gears are the quietest and smoothest form of gearing.

Q: What is a worm gearbox structure?

A: A typical worm gear features a worm wheel and a worm (similar to a screw) with a perpendicular, non- intersecting shaft, oriented at 90 degrees to each other. The worm wheel plays the role of the driven element, while the screw plays the driving element.

Q: What is the advantage of a worm gear?

A: The advantages of worm gears include noise and vibration reduction as well as compactness. A worm gear system is the most compact type of gearing system; this makes it capable of being placed in very small spaces and still providing high ratio speed reduction.

Q: What is the main advantage of using worm gears?

A: Worm gears' main advantage is its capacity to generate high reduction ratios and, as a result, high torque multiplication. In low- to medium-speed applications, they can also be utilised as speed reducers.

Q: What are the pros and cons of worm gears?

A: Worm gears have advantages such as low noise and low vibration, but because power transmission is effected by sliding contact, it also has the disadvantage of retaining heat and its transmission efficiency is not high (in the case of a cylindrical worm gear, the general efficiency is about 30 - 60%).

Q: What is an example of a worm gear?

A: Worm gears are known to run smoothly and quietly, as long as they are properly mounted and lubricated. Due to these features, typical worm gear applications include presses, small engines, lifts and elevators, rolling mills, conveying engineering, mining industry machines, on rudders, and worm drive saws.

Q: Where are worm gears used in real life?

A: The simplest use of a worm gear design can be found on stringed instruments such as guitars, double basses, banjos and violins. The tuning mechanisms usually found on the head of the instrument use a simple type of worm gear to tighten or loosen the strings in order to raise or lower the pitch.

Q: Can worm gears reverse?

A: This is the only type of worm gear that allows bi-directional turning. The worm gears used in industrial applications do not reverse, making them valuable to regulate speed and when braking and/or holding are required.

Q: Do worm gears lock?

A: In theory, a worm gear is self-locking when the static friction angle is larger than the helix angle of the worm. The static friction angle is described as the angle where the load above will start to move.

Q: What is the difference between a worm gear and a screw gear?

A: The lead screw and the worm (in a worm drive) seem similar in shape, but are different in what they interface with. A lead screw turns rotary motion into linear motion. A worm drive turns rotary motion into rotary motions (with a gear ratio).

Q: What is the difference between worm and worm gear?

A: These gear sets transmit power between two non-parallel, non-intersecting shafts, generally have an angle of 90 degrees between them. A worm is essentially a thread wrapped around a shaft while a worm gear is a gear with corresponding gear features to that thread.

Q: What is the efficiency of a worm gearbox?

A: The worm drives by its threads sliding into contact with the teeth of worm wheel. This constant sliding action generates heat due to friction and causing the deduction in efficiency as low as 40-50%.

Q: How to increase worm gear efficiency?

A: Increase friction between the working surfaces to reduce slippage losses.
Increase strength of the materials of the working surfaces.
Use synthetic lubricants to reduce heat build-up without reducing contact friction.

Q: Which is better worm gear or gear motor?

A: For applications demanding precise control, smooth operation, and versatility, inline geared motors with helical gears may be the optimal choice. On the other hand, if the application requires high torque at low speeds and self-locking capabilities, worm-geared motors are better suited.

Q: How to make a worm wheel gear?

A: The typical method for manufacturing worm gears is hobbing using a hob or cutting tool; this cutting tool is similar to the gear with which the worm gear will mate. Worms can be turned, hobbed, milled, or ground.

Q: What is the construction of worm gear?

A: In a worm gear set, the worm and gear must have the same hand, pitch, number of threads, and tooth dimensions. They also must have the same pressure angle and lead angle. Right hand worm and worm gear sets are considered standard.

Q: What material is a worm gearbox made of?

A: For KHK standard gears, mechanical structural carbon steel (S45C), mechanical structural alloy steel (SCM440), stainless steel, etc. are used for worms, while cast iron (FC200), phosphor bronze and aluminum bronze, and MC nylon (an engineering plastic) are used for the worm wheel.

Q: How many worm gearboxes are there?

A: There are roughly two types of worm gears. One is a cylindrical worm that meshes with a worm wheel as a pair to form the "cylindrical worm gear". The other is the "drum-shaped worm gear" which is a pair consisting of a drum-shaped worm and a worm wheel. The latter type is also called "throated worm gear".

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