Post by WANCHO on Jun 16, 2006 15:30:45 GMT 8
Airsoft Gears Explained
There are four main gears inside a Marui mechabox:
1. Bevel gear(bottom gear): The bevel gear is the gear that makes contact with the motor pinion gear. Its called a bevel gear because the height of the gear teeth is highest at the middle and tapers off towards the edge of the gear, forming a cone shape. Bevel gears are useful when the direction of a shaft's rotation needs to be changed.
This image shows how the pinion gear would interact with the bevel gear in your mechabox, the pinion gear would be the smaller one. If youre paying attention you'll notice that both bevel and pinion gears are beveled.
2. Spur gear(middle gear): The spur gear is just that, a
basic spur gear. Theres really nothing to explain, spur gears are the most basic type of gear. They are found all over your house in mechanical items.
3. Sector gear(top gear): The sector gear is the top most gear that interfaces with the piston. The name sector comes from the fact that the gear only has teeth on some sections of the gear. The sector gear does much more than just compressing the spring in a gearbox, it also operates the tappet plate which feeds the bb's.
4. Piston: Some will try to argue that the piston is not a gear but this is not true, the piston is a rack gear. Racks(also know as straight gears) are used to convert rotational movement to translational movement. There are two types of piston rack teeth, full and half, I will get into that after explaining flat vs. helical cuts.
There is also a fifth gear and its positioned on the motor, it is called a pinion gear.
Defining the different cuts in gears:
In airsoft gear applications there are two prefered ways to cut a gear: straight cut, commonly called flat cut in airsoft and just plain spur gears in general (it gets confusing sometimes) or helical cut.
Straight/flat cut gears have teeth that are cut parallel to
the shaft, the teeth is straight and does not radiate outwards at an angle.
Helical cut gears have teeth that are at an angle (helix) to the shaft, rather than parallel to it. The result of this angle is that the helical cut gear's teeth are longer than that of a equal diameter flat cut gear.
The advantages of having longer gear teeth are:
1. Increased tooth strength.
2. Increased load capacity due to greater surface contact.
3. Generally helicals will have a lower sound signature than flat cut gears, this is why most gears in a automobile are helical.
Disadvantages are:
1. Increased suface contact reduces overall efficiency of the gears compared to a flat cut gear.
2. At high rpm the greater surface contact also increases
wear on the gears, therefore airsoft helical cut gears are not meant for super fast rate-of-fire upgrades.
3. When buying Systema helical gears you will have two choices, helical and all helical. The helicals will require the use of a special piston with half rack teeth. The second set of helicals Systema offers is called all-helicals and they allow you to use the stock type full rack teeth piston.
Gear Ratios: Speed vs. Torque
The main use of gears are:
1) To reverse the direction of rotation
2) To increase or decrease the speed of rotation
3) To move rotational motion to a different axis
4) To keep the rotation of two axes synchronized
In airsoft the gears serves two main purposes:
1) Moving rotational axis to a different axis - The piston transfers the rotational movment of the gears into lateral movement to compress the spring.
2) Increasing and decreasing the speed of rotation - The airsoft electric motor spins at a high RPM but doesn't produce much torque, with gear reduction the output speed of the motor can be lowered while raising the torque output.
The way gears reduce the output speed is by utilizing different gear ratios, gear ratio can be defined (a very
basic description) as:
-A gear ratio is a numerical value that describes the rota
tional relationship between two gears.
-A gear ratio can also describe the relationship between the first and last gear in a gear train.
Imagine a small gear(pinion gear) connected to a larger gear(drive gear) twice its size, for every rotation of the large gear the smaller one will turn two times. The gear ratio for this set up would be 2:1.
Speed (RPM) - To be filled in later....
Torque - To be filled in later......
Going by this model you can see that there is a trade off of speed for torque and visa versa, you will have to determine the application (speed or torque) and choose accordingly.
Adapted from: Gunsmith Workshop
pageproducer.arczip.com/daedalus03/workshop.html
There are four main gears inside a Marui mechabox:
1. Bevel gear(bottom gear): The bevel gear is the gear that makes contact with the motor pinion gear. Its called a bevel gear because the height of the gear teeth is highest at the middle and tapers off towards the edge of the gear, forming a cone shape. Bevel gears are useful when the direction of a shaft's rotation needs to be changed.
This image shows how the pinion gear would interact with the bevel gear in your mechabox, the pinion gear would be the smaller one. If youre paying attention you'll notice that both bevel and pinion gears are beveled.
2. Spur gear(middle gear): The spur gear is just that, a
basic spur gear. Theres really nothing to explain, spur gears are the most basic type of gear. They are found all over your house in mechanical items.
3. Sector gear(top gear): The sector gear is the top most gear that interfaces with the piston. The name sector comes from the fact that the gear only has teeth on some sections of the gear. The sector gear does much more than just compressing the spring in a gearbox, it also operates the tappet plate which feeds the bb's.
4. Piston: Some will try to argue that the piston is not a gear but this is not true, the piston is a rack gear. Racks(also know as straight gears) are used to convert rotational movement to translational movement. There are two types of piston rack teeth, full and half, I will get into that after explaining flat vs. helical cuts.
There is also a fifth gear and its positioned on the motor, it is called a pinion gear.
Defining the different cuts in gears:
In airsoft gear applications there are two prefered ways to cut a gear: straight cut, commonly called flat cut in airsoft and just plain spur gears in general (it gets confusing sometimes) or helical cut.
Straight/flat cut gears have teeth that are cut parallel to
the shaft, the teeth is straight and does not radiate outwards at an angle.
Helical cut gears have teeth that are at an angle (helix) to the shaft, rather than parallel to it. The result of this angle is that the helical cut gear's teeth are longer than that of a equal diameter flat cut gear.
The advantages of having longer gear teeth are:
1. Increased tooth strength.
2. Increased load capacity due to greater surface contact.
3. Generally helicals will have a lower sound signature than flat cut gears, this is why most gears in a automobile are helical.
Disadvantages are:
1. Increased suface contact reduces overall efficiency of the gears compared to a flat cut gear.
2. At high rpm the greater surface contact also increases
wear on the gears, therefore airsoft helical cut gears are not meant for super fast rate-of-fire upgrades.
3. When buying Systema helical gears you will have two choices, helical and all helical. The helicals will require the use of a special piston with half rack teeth. The second set of helicals Systema offers is called all-helicals and they allow you to use the stock type full rack teeth piston.
Gear Ratios: Speed vs. Torque
The main use of gears are:
1) To reverse the direction of rotation
2) To increase or decrease the speed of rotation
3) To move rotational motion to a different axis
4) To keep the rotation of two axes synchronized
In airsoft the gears serves two main purposes:
1) Moving rotational axis to a different axis - The piston transfers the rotational movment of the gears into lateral movement to compress the spring.
2) Increasing and decreasing the speed of rotation - The airsoft electric motor spins at a high RPM but doesn't produce much torque, with gear reduction the output speed of the motor can be lowered while raising the torque output.
The way gears reduce the output speed is by utilizing different gear ratios, gear ratio can be defined (a very
basic description) as:
-A gear ratio is a numerical value that describes the rota
tional relationship between two gears.
-A gear ratio can also describe the relationship between the first and last gear in a gear train.
Imagine a small gear(pinion gear) connected to a larger gear(drive gear) twice its size, for every rotation of the large gear the smaller one will turn two times. The gear ratio for this set up would be 2:1.
Speed (RPM) - To be filled in later....
Torque - To be filled in later......
Going by this model you can see that there is a trade off of speed for torque and visa versa, you will have to determine the application (speed or torque) and choose accordingly.
Adapted from: Gunsmith Workshop
pageproducer.arczip.com/daedalus03/workshop.html
