Bevel Gears

Introduction to Gears, and SolidFace Bevel Gears

To better understand bevel gears, we need to understand what the regular gear is. Gears form a crucial part of various machines and mechanically driven motors, that help us do work.

The main function of a gear system is to help change the speed, torque, and direction of a power source, to create a mechanical advantage for the machine or motor it’s being used for.

A combination of gears can produce various kinds of motions, like rotational motions, translational and simple harmonic motions, etc.

Also, gears are made in various sizes and these different sizes can be combined, producing mechanical advantage, with differing diameters and rotational speeds.

Bevel gears are one of the several types of Gear devices, that help transfer the aforementioned motion type from one end of the mechanical system to another.

One strong reason why Bevel Gear is preferred to most other gear types is the fact, that while other types of gear translate their motion laterally, Bevel gears change the direction of these motions as we would see as we continue.

What’s a Gear?

A Gear is a type of machine element that’s built with a cut or inserted teeth that are around a cylindrical or cone-like shaped surface with equal spacing between them. The teeth inserted in the gear allows them to fit together, rotate, and transmit torque, while in motion.

Torque is the force that causes a rotational output in machines or electrical motors. This torque is common in moving mechanical systems like motorcycles, boats, and automobiles.

Just like in bevel gears, the Gears itself barely stands alone and is usually combine with two, three, or more gears to create a mesh. A meshed gear is two or more gears working together, in a sequence, to form a transmission or a gear train.

Also, Gears are known as cogs or cogwheels.

History of Gears

Gears have been around for some time now, the earliest use of them was in the 4^th Century BC in China, during the Zhou dynasty.

Also, Gears were used in Ptolemaic Egypt, in the 3^rd Century BC in the Great Alexandrian school and library, a leading historical school of the past that founded a lot of classical and modern scientific theories, and famously tutored by Greek Philosophers like Polymath, Archimedes, and Ajora.

However, in recent history, the oldest use of the gear was in the 1386 Salisbury cathedral clock, which is one of the world’s oldest mechanical clocks and many other Gothic cathedrals and their clock machinery.

Parts of a Gear System

Teeth

The teeth of the gear are the portion that makes contact with other gears while in contact during a mesh. The teeth allow two or more gears to mate together, while they’re in a mesh.

Also, the pitch has equating distances, points, and when they mesh properly they’re responsible for holding the gears together, preventing them from slipping and can exhibit efficiencies up to 98%.

Radius

The radius of a gear system is can be in two forms, either the root radius or the addendum radius. The root radius of the gear is the distance from the center of the gear to the base of the teeth.

While the addendum radius or pitch radius is the distance from outside the teeth to the center of the gear.

Types of Gears

All gears are categories into internal and external gears, with external gears being more prominent and common than the internal gears. Even our bevel Gears are part of these external gears, in fact, internal gears don’t have many types and are regarded as a planetary gear.

That said, the types of gears covered here, are the external gears. These external gears include the following gears listed below:

• Internal gears
• Spur gears
• Helical gears
• Double Helical gears
• Bevel gears
• Hypoid gears
• Crown gears
• Worm gears
• Rack and pinion
• Screw gear

Spur Gear

Spur gears are the simplest and most common of the gear types and are also called straight-cut gears. The spur gear is a cylinder with teeth projecting radially. The teeth of the gear are made to be straight and aligned parallel to the axis of rotation, so there can mesh correctly together.

One major cause of disinterest in the spur gears that there don’t perform very well at high speeds because they tend to be too noisy and don’t have any axial thrust necessary for carrying loads.

Helical Gear

The Helical gear uses the similar parallel shafts as seen in spur gears and the winding tooth lines are also inserted around the cylindrical gears. But, they have better teeth meshing and can transmit higher loads than their spur gears counterpart.

Since their tooth lines are arranged at an angle, they can create thrust force in the axial direction, which helps in their thrust bearing capacity and is useful in high-speed applications.

Hypoid Gear

Hypoid gear is designed with a hyperbolic pitch that makes the hypoid gears suitable to operate with shafts at 90^o. Hypoid gears have similarities with hypoid bevel gears and spiral bevel gears.

Bevel Gears

Bevel gears are components used basically for power transmission, for adjusting or changing the shaft rotation, direction and reducing speed and increasing the torque between non-parallel rotating shafts.

It’s used on shafts with intersecting axes,and on shafts whose axes do not intersect in special cases. The bevel gear is classified by their tooth-shaped and has different types.

Types of Bevel gear

As earlier stated, the Bevel gears are classified according to the shape of their tooth. Though engineers, designers may not agree on the different types of Bevel gear available, these are the more accepted ones.

The following are the types of Bevel gears available for designers.

• Straight bevel gears
• Hypoid bevel gears
• Spiral bevel gears
• Zerol bevel gears

Straight Bevel Gears  

Straight bevel gears are the most common type of bevel gear and this is because their design is simple. There have straight teeth, that resembles a spur gear, except for their conical surface.

Hypoid Bevel Gears

In hypoid bevel gears, the pitch surface is designed to be hyperbolic and not conical. Hypoid have larger pinion diameter, smoother mesh, and overall longer life.

Hypoid bevel gear is similar to spiral bevel gears and the main difference is that the mating gear’s axes don’t intersect. The Hypoid bevel gears were frequently used in automobile rear axles.

Spiral Bevel Gear

The Spiral bevel gears have their tooth lines formed along spiral lines, which makes their teeth angled. Spiral bevel gears are usually very handy and have a typical angle of 35^o.

There are very useful since there engage more gradually in engaging the force than regular bevel gears, which means that there is a less immediate transfer of force within the gear, so there will be less noise and stress.

Zerol Bevel Gear

The Zerol bevel gears are another type of bevel gear that is more of an intermediate between the straight bevel gear and the spiral bevel gear, as they combine the features of both.

The name Zerol is derived from the fact that it has a zero spiral angle. The Zerol gears can be turned in any direction without much difficulty.

How Bevel Gears are Manufactured

Since bevel gears are widely used in various types of machinery, they’ve become very important to engineers, so is their manufacturing and their manufacturing design, materials, and process.

The materials employed to produce them include the following:

Steel

Steel is very much preferred for its strength and for its resistance to wear and tear by abrasion.

Cast Iron

Also, cast iron is widely used for its good wearing properties, machinability, and malleability, which is its ability to be transformed into very complicated shapes during forging and casting process. The only serious issue with the cast iron is, that it’s very poor with corrosion.

Cast Steel

Cast steel, on the other hand, combines the ease of manufacturing in cast iron and waring resistance of steel metals to produce a material that’s used to create bevel gears that can withstand high stress.

Aluminum

Aluminum bevel gears are quite popular in areas where corrosion is a serious concern. However, Aluminium bevel gears are also low weight and so are very good for providing low inertia of rotating mass. Which is an important advantage these types of gears have.

Alloy Steel

Furthermore, with Alloys Steels the possibility is endless for manufacturers as they can combine unique features of several metals to get the best type, suitable for their needs.

However, Alloy Steels are used where low teeth wear and high teeth strength are required of the bevel gear.

Non-Metallic Materials

Non-Metallic Materials are suitable to make bevel gears that are noiseless in their operations, even at high peripheral speeds.

Plain Carbon Steel

Lastly, Plain carbon steel is highly preferred as materials where high toughness and high strength are needed, this includes major industries activities, etc.

Considerations Made Before Choosing Materials

Materials used for work bevel gears and other gears are not selected at random, but as specified from the previous entry, are made based on some reasons. The considerations used to select the type of materials include the following:

• Type of work
• Shock resistance
• Method of manufacture
• Allowable stress
• Peripheral speed
• Required dimensions and weight of the drive
• Degree of accuracy required

Uses of the Bevel gears

Bevel gears have been used to perform many different functions and industrial applications in various categories of industries and form fundamental components of several finished products and machinery.

• Bevel gears are the main mechanism for the hand drill, as the bevel gear changes the rotation of the chuck from its vertical direction to a horizontal rotation.
• Also, Bevel gears very useful in rotorcraft drive systems. Spiral bevel gears help to redirect the shaft from the horizontal gas turbine gas to the more vertical rotor.
• Furthermore, Bevel gears are also used in differential drives, as it transfers power to two axles spinning at different velocities. This differential drive is also featured in automobiles.
• Lastly, Bevel gears are also used in the Bevel gear planer, which is a metalworking machine.

Industrial and Mechanical Applications of Bevel Gears

Bevel gears are very useful in engineering and especially mechanical engineering where their use is enormous. Some of their mechanical uses are:

• Automotive drivetrains
• Marine and shipbuilding
• Printing press
• Locomotive
• Power plants
• Steel plants
• Cooling towers
• Railway track inspection machines

Advantages of Using Bevel Gears

Bevel gears have many advantages there add to every machinery they’re used in. Some of these include the following.

• Power transmission at perpendicular angles (90^o) inclinations.
• Bevel gears are much efficient with 98.5% compared to worm gears.
• Smooth and noiseless power transmission.
• Good flexibility, since there have adjustable angles of operations and the possibility of changing force output by simply reversing the number of teeth in the bevel gear.
• Can be made from different materials
• Adjustable mechanical advantage
• Greater torque capacity when compared with other gears like the worm gears of the same size.
• Ratio compatibility.

Disadvantages of Using Bevel Gears

Like every machine part, Bevel gears fail at some point. Below are the disadvantages of using Bevel Gears.

• The Bevel gear is not made to work independently, but rather as a complementary wheel to other gears.
• They’re difficult to assemble and must be precisely mounted to be fully operational.
• The bevel gear shaft’s bearings can’t withstand significant force.
• Have a limited gear ratio of less than 5.

Bevel Gear Standardisation

The standardization of Bevel gears is done to help ensure the accuracy of the gear. These standards are regarded as a precision class and they are set by ISO, JIS, AGMA, DIN, etc.

As a result of these Precision class, designers can ensure that their bevel gears can have maximum power capability, minimum size, minimum noise, and accurate rotation.

These standards are very useful for handmade drawings. Like the JIS specifies pitch error, runout error, tooth profile error, helix deviation, etc.

How to Use SolidFace in Creating Bevel Gears

To Create and design Bevel Gear using SolidFace, we use Toolbox to draw them. The following steps below clearly explain the process involve.

• Select the New SolidFace document to create a new work page, continue by selecting “Assembly” and click “Ok”.
• Select “design library”.
• Open your toolbox and select standard, choose the standard of your choice e.g ISO standard
• From the items listed under ISO standard, Select Power Transmission.
• In Power Transmission, you’ll find another two options: Chain wheel and Gear. Choose Gear.
• Again inside of the Gear option, you’ll find many options for Gear type like the Helical Gear, Internal Spur Gear, and different types of Bevel Gear, etc.
• Decide on the Bevel Gear of your choice example select the Straight bevel gear.
• Click and drag the Straight bevel gear from the design library to the work page and you’ll have your rough Bevel gear ready.

Formatting SolidFace’s Bevel Gears

• After the Click and drag process from the previous entry, It will take your SolidFace software a short while to calculate Bevel Gear, but immediately after this, a window opens for “Configure Component”.
• Inside the “Configure Component” options, a list of “Properties” is available for rearranging and you’ll do this by simply inputting your values in them.
• But for this example, click on “module” and select “5”, and SolidFace will calculate. After, this, you’ll observe the changes that would affect the Bevel Gear.
• Then Select the number of teeth, for example, select 30.
• Then click on pinion number of teeth, it will calculate slow, then effect the changes.
• The pressure angle should be at 20, which is the standard.
• Then select the face width and set it at 30. You’ll observe that the face width of your Bevel gear would have increased.
• Then for the diameter, set it at 50 and not 100, it will calculate and continue.
• Also, for the Mounting distance, set it at 50.
• Furthermore, for the shaft diameter, hover over to 30 and select it, and your SolidFace software will calculate the inputted values.
• After, this hover over just immediately below the bar where the “Configure Component” is written, and you’ll see the green swoosh and red ‘x’, click the green swoosh to “ok” all you’re your already made settings, and then, SolidFace will calculate it, then continue.
• The SolidFace software will ask if you require more than one bevel gear, if you do, simply click on any area of the work page to get an exact copy of the bevel gear you just worked on.
• This process of creating new bevel gears will continue until your cancel it at the “insert component” area.
• Go ahead and save but, don’t save the file as Assembly, rather, change the “Save as type” to Part and type the file name and then Save.

Benefits of Using SolidFace Bevel Gear Creation

• SolidFace provides designers to design Gears with any mandatory skill in drawing.
• Automatically provides several standards to choose from and to select the one to work with.
• All units are flexible and adjustable and could be revised by the designer or any other person who needs to use the drawing.
• The drawing can be created in just 5 minutes or less, which much faster than using hands.
• Simulations and testing can be performed on the Bevel Gear.
• Multiple Bevel Gears can be created from the original bevel gear, without any need to begin the drawing process from the start.
• It’s user friendly as the list of options to be edited is arranged sequentially you could easily move from one option to the next.

Last Words

Bevel gears have been in part of human machinery since the ancient, classical times, and has formed a critical part of our industrial process since the dawn of the recent industrial age. That said, it’s hard to see a future without Bevel gear and gears in general, so it’s important to better produce them.

With leading CAD software, like SolidFace, this can be done by nearly anyone and the formerly long, tedious process has been reduced to a series of steps.

Now, designers everywhere can virtually create sophisticated gear supported machinery with ease, so manufacturers, in turn, can also make advanced technological devices like Space Rockets, Robots, and so on. The possibility now is endless.