Zhejiang Sankai Mechanical and Electrical Co., Ltd

Hypoid Gearbox

What is Hypoid Gearbox



Hypoid gearboxes are special configurations of bevel gearboxes. In such gearboxes, the axes cross on two parallel planes. In contrast to other bevel gearboxes, there is an axis offset here. Also important: In practice, the input shaft and output shaft can rotate in the same direction as well as in opposite directions. The high torque in conjunction with the sliding gearing generates higher friction in hypoid gearboxes. As a result, these gearboxes operate with relatively high losses. For this reason, they are often part of multi-stage gearboxes.


Advantages of Hypoid Gearbox

High torque capacity

Hypoid gears have a larger contact area between the teeth than standard bevel gears, resulting in increased load-carrying capacity and higher torque transmission.


Smooth operation

The helical and curved tooth geometry allows for gradual engagement, reducing noise and vibration during operation. This makes hypoid gears particularly suitable for automotive applications, where noise and vibration reduction are important factors.

Compact design

Hypoid gears can transmit power between non-intersecting shafts in a compact and efficient manner, making them an ideal choice for space-constrained applications such as automotive differentials.


Hypoid gears offer greater flexibility in terms of shaft angles and offsets compared to other types of gears, allowing for more versatile designs.



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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.


How to Installation Hypoid Gearbox

Proper Alignment: Ensure accurate alignment of the hypoid gear system components, including the input and output shafts, housing, and bearings. Misalignment can lead to premature wear, noise, and decreased efficiency.

Torque Application: Follow the manufacturer's recommended torque specifications when tightening fasteners, such as bolts and nuts. Applying the correct torque helps maintain the integrity of the gear system and prevents loosening during operation.


Before installation, make sure the gear system is properly lubricated with the recommended lubricant. Ensure that the lubricant is distributed evenly throughout the gear mesh during assembly.

Gear Preloading

Some hypoid gear systems require preloading to achieve proper gear meshing and load distribution. Follow the manufacturer's guidelines for applying the appropriate preloading force, if necessary.

Bearing Installation

Pay careful attention to the installation of bearings supporting the hypoid gear system. Ensure that the bearings are properly seated, aligned, and securely mounted according to the manufacturer's instructions.


Geared Motor Units


Design of Hypoid Gearbox

Geometry: Hypoid gears are characterized by their hyperboloid shape. Unlike standard bevel gears, which have a conical geometry, hypoid gears have an axis that does not intersect with the gear face.

Tooth Profile: They typically feature a spiral tooth profile, which allows for smoother and more gradual engagement compared to straight-cut teeth.

Axis Offset: A key feature of hypoid gears is the axis offset – the axes of the gears are not on the same plane. This offset enables larger diameter gears and greater tooth contact.

Lubrication Requirements: Due to their design and the higher pressure on the teeth, hypoid gears require special lubricants to handle the increased load and friction.

Application of Hypoid Gearbox



Automotive Industry: Hypoid gears are commonly used in automotive applications, especially in the drivetrain systems of rear-wheel-drive and all-wheel-drive vehicles. They are widely employed in differential assemblies to transfer torque from the driveshaft to the rear wheels. The offset design allows for compact and efficient packaging of the drivetrain.


Power Tools: Hypoid gears are used in power tools such as angle grinders and circular saws to transfer power from the motor to the cutting blades. Their high torque transmission capabilities make them suitable for heavy-duty applications.


Robotics and Automation: Hypoid gears can be found in robotic arms and automation systems where high torque and efficiency are required. Their offset design allows for efficient power transmission between non-parallel axes in compact spaces.


Industrial Machinery: Hypoid gears are utilized in various industrial machinery, including agricultural equipment, construction machinery, and material handling systems, where high torque and efficiency are essential.


Marine Propulsion: In some marine propulsion systems, hypoid gears are used to transfer power from the engine to the propeller shaft, enabling efficient propulsion in watercraft.


Wind Turbines: Hypoid gears are employed in wind turbines to transfer power from the turbine blades to the generator, converting wind energy into electrical energy.


Aviation: In aircraft applications, hypoid gears may be used in certain auxiliary power systems and mechanisms.


HVAC Systems: Hypoid gears can be found in some HVAC systems to transfer power from motors to fans and blowers.



How Hypoid Gears Work in Reducers

Single stage hypoid reducers can achieve reductions with ratios of 3:1 to 10:1. In comparison to straight or spiral bevel reducers, which need an additional planetary stage to achieve the reduction, the single stage hypoid is well suited for compact applications that fall in this range of reduction ratios.
Hypoid gears can be combined with planetary gears in multiple stage gearboxes to reach
higher reduction ratios, typically up to 100:1 with a single additional planetary stage. In that case, hypoid gears should be chosen over bevel gears for the 90° angle transmission, if the configuration of the system requires non-intersecting shafts or if higher torques need to be transmitted with low noise levels.
When compared to worm gear reducers, hypoid reducers are a better option in terms of efficiency and heat generation. They require less maintenance and fit into tighter places while delivering the same amount of torque. For long term cost savings, hypoid reducers are an alternative to worm gear reducers that should be considered.

Geared Motor Units


The Manufacturing Process of Hypoid Gears

Design: The process begins with the design of the hypoid gear. This includes determining the gear specifications such as tooth profile, size, ratio, and load requirements. Computer-aided design (CAD) software is commonly used to create a 3D model of the gear.


Gear Cutting: Once the design is finalized, the gear cutting process begins. Hypoid gears are typically produced using specialized gear cutting machines such as Gleason or Klingelnberg machines. These machines use a cutting tool with a specific shape to generate the gear teeth.


Gear Blank Production: Before the gear cutting process, gear blanks need to be produced. Gear blanks are typically made from steel or other suitable materials. The gear blank is a cylindrical piece of material that will eventually be shaped into the final gear.


Roughing: In the roughing stage, the gear cutting machine removes excess material from the gear blank to bring it closer to the final shape. This process is done to reduce the machining time required for the finishing stage.


Finishing: In the finishing stage, the gear teeth are precisely machined to achieve the desired tooth profile and surface finish. The gear cutting machine generates the exact shape and dimensions of the teeth based on the design specifications.


Heat Treatment: After the gear teeth are machined, heat treatment is often performed to enhance the hardness and strength of the gear. This involves heating the gears to a specific temperature and then rapidly cooling them through processes such as quenching.


Gear Inspection: Once the gears are heat-treated, they undergo a thorough inspection process to ensure they meet the required quality standards. Various inspection techniques, such as coordinate measuring machines (CMM), gear analyzers, and visual inspection, are used to check the dimensions, tooth profile, and other critical parameters.


Gear Finishing Operations: After inspection, the gears may undergo additional finishing operations, such as grinding, honing, or lapping, to achieve even higher precision and improve the surface finish.


Gear Assembly: In some cases, hypoid gears are assembled into gearboxes or other mechanical systems. This involves fitting the gears with bearings, shafts, and other components to create the complete gear assembly.


The Meshing Analysis of Hypoid Gear

Meshing Angles:
Meshing angles in hypoid gear refer to the angles formed between the tangent to the pitch cone and the line of action of the tooth force.
The meshing angle affects the contact pattern, load distribution, and sliding behavior of the gear teeth during engagement.
Proper meshing angles are crucial to prevent edge loading and ensure smooth tooth engagement.


Line of Action and Path of Contact:
The line of action is the theoretical line along which the force is transmitted between the mating teeth.
The path of contact is the actual path traced by the contact point during gear rotation.
Analyzing the path of contact helps determine the extent of tooth engagement and optimize tooth profiles.


Tooth Contact Pattern:
The tooth contact pattern refers to the specific area of tooth contact during meshing.
Proper contact pattern is critical for load sharing, minimizing stress concentrations, and reducing noise and vibration.
Analyze the contact pattern using techniques like tooth contact analysis or computer simulations.


Load Distribution:
Analyzing load distribution involves understanding how the applied load is distributed across the gear teeth.
Uneven load distribution can lead to premature wear, pitting, and failure.
Load distribution is influenced by factors such as gear geometry, tooth profile, and helix angles.


Tooth Profile Modifications:
Tooth profile modifications, such as crowning and tip relief, can be applied to optimize the tooth contact pattern and load distribution.
Modifications help mitigate issues like edge loading and improve overall gear performance.


Sliding Action and Friction:
Due to the sliding meshing action of hypoid gear, friction and wear are important considerations.
Sliding generates heat, affecting lubrication and wear characteristics.
Analyzing sliding behavior helps optimize lubrication and reduce friction-related issues.


Gear Contact Ratio:
The gear contact ratio is the ratio of the arc of action to the pitch circle circumference.
A higher contact ratio indicates better load distribution and reduced sensitivity to misalignment.


Tooth Interference and Clearance:
Analyze tooth interference to prevent collisions or interference during gear engagement.
Ensure proper tooth clearance to avoid jamming and ensure smooth meshing.


Computer Simulations and Analysis:
Use computer-aided design (CAD) software and specialized gear analysis tools to simulate meshing behavior.
Finite element analysis (FEA) can be employed to analyze stress distribution and deformation during meshing.


Optimization and Iteration:
Iteratively adjust gear parameters like meshing angles, tooth profiles, and modifications to optimize the contact pattern and load distribution.
Accurate meshing analysis of hypoid gear is crucial to ensure efficient power transmission, minimize wear, reduce noise, and extend gear life. It requires a combination of analytical methods, computer simulations, and practical experience in gear design and analysis.


High Ratio Gear Reducer


Hypoid Gears Vs Bevel Gears

Hypoid gears belong to the bevel gear family, which includes two categories:
Straight teeth and spiral teeth. Although hypoid gears technically belong to the spiral teeth category, they have enough specific attributes to make up their own category.
In contrast with a standard bevel gear, the mating gear shafts for hypoid gear sets do not intersect, because the small gear shaft (pinion) is offset from the larger gear shaft (crown). The axis offset allows the pinion to be larger and have a greater spiral angle, which increases the contact area and the tooth strength.
While sharing a similar shape, the main difference between hypoid and bevel gears is the offset of the pinion. This offset allows a greater flexibility for the design and increases the pinion diameter and the contact ratio (the average number of tooth pairs in contact is typically 2.2:1 to 2.9:1 for hypoid gear sets). As a result, higher levels of torque can be transmitted with lower noise levels. However, hypoid gears are usually less efficient (90 to 95%) than a similar set of spiral bevel gearing (up to 99%). The efficiency decreases as the offset increases, and special attention must be given to lubrication to reduce friction, heat, and wear due to the sliding action of hypoid gear teeth.

Maintenance and Inspection of Hypoid Gears



Regular Lubrication: Hypoid gears require proper lubrication to minimize friction and wear. Follow the manufacturer's recommendations regarding the type and frequency of lubricant changes. Maintain the appropriate oil level and monitor its condition regularly.

Visual Inspection: Conduct visual inspections of the gear teeth and housing for any signs of damage, such as cracks, chips, or excessive wear. Inspect the gear meshing area to ensure proper alignment and contact patterns.

Noise and Vibration Analysis: Listen for abnormal noise or vibrations during gear operation. Unusual sounds or vibrations may indicate issues with gear meshing, misalignment, or worn components. Investigate and resolve such issues promptly.

Torque and Backlash Measurement: Periodically measure the torque and backlash of the hypoid gears. Torque measurements help identify any abnormalities in the power transmission system, while backlash measurements indicate the clearance between gear teeth. Deviations from the manufacturer's specifications may require adjustments or repairs.

Gear Tooth Wear Analysis: Use specialized tools, such as gear analyzers or contact pattern checkers, to evaluate the wear patterns on the gear teeth. This analysis provides valuable information about the gear meshing characteristics and identifies any irregularities or misalignment that may require attention.

Temperature Monitoring: Keep an eye on the operating temperature of the hypoid gears. Abnormally high temperatures can indicate excessive friction, inadequate lubrication, or other problems. Address the underlying issues promptly to prevent further damage.

Maintenance Records: Maintain comprehensive records of all maintenance and inspection activities, including dates, measurements, observations, and any corrective actions taken. These records help track the gear's performance over time and assist in identifying any recurring issues or trends.



Q: What is the purpose of a hypoid gear?

A: Hypoid gears are a unique category of spiral bevel gears that are used to transmit rotational power between two shafts at right angles. Invented by Ernest Wildhaber in the early 1920s, hypoid gears were used predominantly in the drive trains of heavy trucks.

Q: What is the difference between a hypoid gear and a differential?

A: Hypoid gears are commonly used in automotive differentials to transfer power and distribute torque in vehicles. Differentials are an essential component of the drivetrain that allows the wheels on the same axle to rotate at different speeds while receiving power from the engine.

Q: What is the difference between hypoid and regular gear oil?

A: Hypoid gear oils can have higher viscosities just like other gear oils, but hypoid gear oils contain special extreme pressure and anti-wear additives that increase its resistance to breakdown under the high temperatures and mechanical pressure produced by the sliding surfaces of a hypoid gearbox.

Q: What is the efficiency of a hypoid gearbox?

A: Typical ef?ciencies can vary from 40% to 85% for ratios of 60:1 to 10:1 respectively. Conversely, hypoid gear sets are typically 95% to 99% ef?cient.

Q: Is hypoid gear oil the same as GL-5?

A: The contact area of the teeth slide against each other laterally in a hypoid system, so they require high performance oil- oil rated GL-5. "Hypoid" on the bottle doesn't really mean the oil inside has met any specific performance level, but GL-5 does.

Q: Where are hypoid gears used?

A: Hypoid gears are normally used in right-angle drives associated with the axles of automobiles. Tooth actions combine the rolling action characteristic of spiral-bevel gears with a degree of sliding which makes this type of gear critical from the point of view of surface loading.

Q: What is the difference between a hypoid gear and a bevel gear?

A: Hypoid Gears: Hypoid gears offer high mechanical efficiency due to their larger contact area and optimized tooth engagement. They can transmit high torque with minimal power loss. Bevel Gears: Bevel gears generally have slightly lower mechanical efficiency compared to hypoid gears due to their smaller contact area.

Q: Which is better helical or hypoid gears?

A: Our experience shows that the average efficiency of a hypoid gear unit is 88% with two stages and 83% with three stages. The efficiency of a helical bevel gear unit can be up to 98% due to the exclusively rolling friction.

Q: Is Castrol 80w90 a hypoid gear oil?

A: Axle EPX 80W-90 is a Multigrade gear oil fortified to meet the requirements of API GL-5. Its primary use is for hypoid gears featured in automotive differentials but is often specified in highly loaded spiral bevel or planetary gearboxes on offshore installations and onshore drilling sites.

Q: What is the difference between 75W90 and 80w90 gear oil?

A: SAE 75W-90 maintains a more consistent thickness, or viscosity, across a wide temperature range. It's thicker when exposed to high heat and thinner under colder, wintry conditions than 80W-90.

Q: Why do the hypoid gears require special lubricant?

A: Explanation: Hypoid gears require special lubricant because of the extreme pressure between the teeth. The sliding motion of the teeth is effective due to the use of special lubricant.

Q: What is the most efficient gearbox?

A: Planetary, inline helical and bevel helical gearboxes are the most efficient, whereas worm gearboxes are usually the least efficient.

Q: Which gearbox is more efficient?

A: Manual cars are known to be fuel efficient compared to automatic cars, but that gap is narrowing fast. AMT gearbox is an example of being on par with manual cars. Several car manufacturers in India have employed the AMT gearbox to their products since they are affordable and offer the benefits of the automatic gearbox.

Q: What is the most efficient gear system?

A: Helical gearing: This gearing creates rolling-gear interactions, making it the most efficient type. Helical gearing also has several teeth engaged constantly, transmitting relatively high torque, and generating little torque ripple, thanks to smooth transitions between teeth.

Q: What happens if you use GL5 instead of GL4?

A: A GL5 gear oil has about twice as much EP additive as a GL4, ensuring the greatest protection, performance, and efficiency for your hypoid gear system. Don't use a GL4 gear oil in a hypoid gear system. It can not only reduce performance but also damage your gears.

Q: What is the angle of a hypoid gear?

A: Typical pressure angles are 14.5° or 20°, but hypoids sometimes operate at 25°. Helix angle is the angle at which the gear teeth are aligned compared to the axis. Selection tip: Gears must have the same pitch and pressure angle in order to mesh.

Q: What is a hypoid gear a special type of gear like?

A: Hypoid gears were developed by the American Gleason Company. They are cone shaped gears similar to spiral bevel gears except they transmit motion between non-intersecting shafts. The small gear shaft (hypoid pinion side) is offset from the larger gear shaft (hypoid gear side).

Q: What is the main difference in hypoid and amboid gears?

A: Hypoid gears have an offset pinion gear, amboid gears have symmetrically positioned pinion gears, and spiral bevel gears have teeth shaped like a spiral. Each type of gear offers specific advantages and is used in different applications depending on the requirements for torque, efficiency, and noise reduction.

Q: Why is a hypoid gear stronger than a spiral bevel gear?

A: Hypoid gears are used in power transmission products that are more efficient than traditional worm gear drives. They are fairly strong because any load is transmitted through multiple teeth simultaneously.In contrast, bevel gears are loaded through one tooth at a time.

Q: Why is the pinion gear so large in a hypoid gear set?

A: In a hypoid gearbox, the spiral angle of the pinion is larger than the spiral angle of the gear, so the pinion diameter can be larger than that of a bevel gear pinion. This provides more contact area and better tooth strength, which allows more torque to be transmitted and high gear ratios (up to 200:1) to be used.

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