Intro
Case study
The spped copy or rotary distributor is a huge, funnel-like device that receives coal from the coal mine and distributes it into three large bunkers.
A motor reducer, connected to a small gear with 21 teeth, drives it. The large gear is rigidly connected
to the reverse shaft and coupled with it. The large gear has 160 teeth. We should build a mechanism that will rotate
(at the end of the shaft) at the same angular speed as a large, driven gear. Parameters : Drive gear.
Parameters :
Drive gear : z = 21
Driven gerar z = 160
Task
Solution
It is necessary to install an encoder that will obtain the angular speed of the large gear, i.e., the rotating rod.Due to the required angular velocity precision, I opted for a reducer with cylindrical gears.This reducer does not transmit any load but only regulates the angular velocity of the large gear.
And that's why I called it speed transfer transmiter
Problem solution
The transmission ratio is
where are : Z2 = 160 - the number of teeth of the large gear Z1 = 21 - the number of teeth of the small gear Since the upper fraction cannot be shortened, making a model of connected gears is impossible. If he used belts or sprockets, there could be slippage and, thus, an incorrect angular velocity of the large gear.
And just a little help with math ...
If we look carefully, we can see that the numbers are 160 i 21 divisible without a remainder160 by : { 2, 4, 5, 10, 20, 40 i 80 }
21 divide by : { 7 i 3 }
It follows that the transmission ratio can be written as i :
We already have a sketch of two pairs of coupled gears, it is necessary expand fractions transmission ratio so that the number of teeth is greater than the minimum.
We have till now :
and it is the number of teeth of the first pair of gears
for the second gear pair, the number of teeth follows
next step - I adopt the gear parameters
| Gear | Teath num | modul | Note |
|---|---|---|---|
| 1 | 48 | 4 | |
| 2 | 21 | 4 | |
| 3 | 50 | 4 | |
| 4 | 15 | 4 | |
| 5 | 21 | 16 | Inner gear |
Gear 5 is input and connects to ... one of the pinion gears (it doesn't matter which one).
Gear 5 is input and it is i.e. its parameters are a copy of the drive gear (module and number of teeth).
The next logical step is the gear calculation. First, I adopted the module, taking into account the dimensions, and then the gear calculation follows. A handy free gear calculator is here, and I used it for the calculation. After the calculation of the gears, there is the calculation of the shaft, bearings, and construction of the shaft and bearing housing. I chose a splined connection on all gears.
Making gear box
After the construction and preparation of technical documentation, the entire project was handed over to the company "Elmont," which made all the elements except the formwork and the base. Here are some drawings.
assembly draw of the speed reducer
The stand and framework manufacturing
The base and formwork have a role (besides carrying and protecting the elements of the reducer), adjustment of fit and
gearing.
The reducer is designed as floating, i.e. it hangs under the base. Board with encoder
are located on the upper side
The pictures above show the plate is a stand that is used to adjust the teeth of the input gear with the gearview
at the plant. The central screw is used to rotate the reducer, on the back side there will be an average circular one
slot for fixing the rear part of the reducer to avoid vibrations of the same.