Production of fine-grained dish gears. Drawing, description

MODELING
Free library / Directory / Modeling

Production of fine-grained dish gears. Tips for a modeller

Modeling

In mass modeling, cup gears with an end tooth are used quite often. For example, in the manufacture of racing car models. Rotation from the motor shaft to the rear axle is conveniently transmitted by a gear pair: a cylindrical gear on the motor shaft and a dish gear (with an end tooth arrangement) mounted on the rear axle. And here, with all the apparent simplicity of the transmission design, a difficult technological task of its implementation arises. This is perhaps the most "narrow" place in the manufacture of models, even for an experienced modeler.

Of course, for responsible sports competitions, models are equipped with metal gears (steel or bronze), for the manufacture of which professional specialists are involved. Well, what about novice modelers, ordinary schoolchildren of 5-6 grades? The lack of gears often puts an end to their modeling studies.

The dished gear has always been considered especially scarce. It is not possible for schoolchildren to make such manually. Therefore, in order to support beginner modellers, I have developed a simplified technology for making "cogwheels" from thermoplastic materials, such as polyethylene, using special molds.

In this article, we will focus on the casting of bucket gears. One of the most important determining parameters in gears is the engagement modulus m (mm). Only a pair of gears with the same module can provide normal meshing and be used in the manufacture of models. The main parameters of the gear are determined by the formula:

m = D/(z+2),

where: D - outer diameter of the gear, mm; z is the number of teeth.

The engagement modulus values are standardized. For gears made of metal, you can take a small module: 0,5-0,6 mm. But since plastic, especially polyethylene used by us, is inferior in strength to metals, it is necessary to use larger modules (in our case, m = 0,8 mm, z = 26), since with an increase in the module, the size of the tooth as a whole increases, and therefore, and its strength.

A mold for the manufacture of plastic fine-module dish gears (click to enlarge): 1 - base (circle 50); 2 - bottom (circle 50); 3 - insert (circle 22); 4 - matrix (circle 22); 5 - body (circle 50); 6 - gear (polyethylene, polystyrene, capron); 7 - punch (circle 20); 8 - glass (circle 30); 9 - screw (circle 30); material children. 2, 3, 4 - brass, bronze; 1, 5, 7, 8, 9 - steel 45

To obtain the necessary gear, and in several copies (to be enough for all modellers), we design and manufacture a mold. It is not very difficult to make it: it is mainly turning work, the parts are small-sized, and suitable equipment, as a rule, is available in school workshops. When turning parts, attention should be paid to the cleanliness of the surfaces and the accuracy of pairing the punch with the body, as well as the bottom, insert and matrix - the accuracy and quality of the finished gears depend on this. The only detail that can cause difficulties in manufacturing is the matrix. On its end surface (as well as on the gear being manufactured), teeth should be cut with a module m = 0,8 mm.

To ensure the required quality, it is preferable to perform this operation on a special gear-cutting machine. But there is no such equipment in modeling circles (in any case, I have not seen it), and not everyone can afford to order on the side. Therefore, as a compromise, it is possible to process the teeth of the matrix on a conventional milling machine with a modular cutter using a dividing head or other similar device. In the absence of the necessary modular cutter, you can sharpen the cut-off cutter. But this is an extreme case, since it will be very problematic to obtain a high-quality tooth profile on the matrix, and therefore on the finished gear. Alas, working in an ordinary provincial school often forces us to make simplifications and compromises.

So, the difficulties of the initial stage have been overcome, all the necessary parts of the mold have been made and fitted to each other. You can proceed to the most important thing - casting the dish-shaped gears that we need so much. And this, as practice has shown, in the presence of a high-quality mold is not difficult at all and is accessible even to students in grades 4-5.

We start assembling the mold with preliminary lubrication with machine oil of those parts that will be in contact with plastic (preferably made of bronze). First, we sequentially install the matrix and the insert into the bottom, and from below we press this assembly with the base, and screw the body from above. We load raw materials into its hole - any thermoplastic: polyethylene, caprolactam (this material is preferable in this case, since it has higher strength and wear-resistant characteristics), polystyrene, etc. The feed material is best used in the form of granules. However, for the members of the circle to acquire industrially granulated raw materials is an almost impossible task. As a rule, we get it from waste bottles, toys, etc., by cutting them into pieces approximately 2x2 mm in size. The required amount of raw material is determined empirically: you can use the scales, putting the finished part on one bowl, and on the other, the starting material is slightly larger in weight than the gear.

Having filled in the raw materials, we insert the punch into the body, screw the glass and finally install the screw. The assembled mold is placed in a muffle furnace and heated to a temperature that ensures the viscous-flowing state of the plastic (determined from a reference book or empirically). After a short exposure, we take out the mold from the oven, quickly tighten the screw until it stops and cool it sharply in water. After disassembling the mold, we remove the gear and make its finishing.

As a result, we get a part of quite acceptable quality, suitable for the manufacture of motor models.

Author: V.Arkhipov

We recommend interesting articles Section Modeling:

▪ Air combat training model Svetlyachok-2

▪ Cord racing model aircraft

▪ Aircraft model Firefly

See other articles Section Modeling.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

A New Way to Control and Manipulate Optical Signals 05.05.2024

The modern world of science and technology is developing rapidly, and every day new methods and technologies appear that open up new prospects for us in various fields. One such innovation is the development by German scientists of a new way to control optical signals, which could lead to significant progress in the field of photonics. Recent research has allowed German scientists to create a tunable waveplate inside a fused silica waveguide. This method, based on the use of a liquid crystal layer, allows one to effectively change the polarization of light passing through a waveguide. This technological breakthrough opens up new prospects for the development of compact and efficient photonic devices capable of processing large volumes of data. The electro-optical control of polarization provided by the new method could provide the basis for a new class of integrated photonic devices. This opens up great opportunities for ... >>

Primium Seneca keyboard 05.05.2024

Keyboards are an integral part of our daily computer work. However, one of the main problems that users face is noise, especially in the case of premium models. But with the new Seneca keyboard from Norbauer & Co, that may change. Seneca is not just a keyboard, it is the result of five years of development work to create the ideal device. Every aspect of this keyboard, from acoustic properties to mechanical characteristics, has been carefully considered and balanced. One of the key features of Seneca is its silent stabilizers, which solve the noise problem common to many keyboards. In addition, the keyboard supports various key widths, making it convenient for any user. Although Seneca is not yet available for purchase, it is scheduled for release in late summer. Norbauer & Co's Seneca represents new standards in keyboard design. Her ... >>

The world's tallest astronomical observatory opened 04.05.2024

Exploring space and its mysteries is a task that attracts the attention of astronomers from all over the world. In the fresh air of the high mountains, far from city light pollution, the stars and planets reveal their secrets with greater clarity. A new page is opening in the history of astronomy with the opening of the world's highest astronomical observatory - the Atacama Observatory of the University of Tokyo. The Atacama Observatory, located at an altitude of 5640 meters above sea level, opens up new opportunities for astronomers in the study of space. This site has become the highest location for a ground-based telescope, providing researchers with a unique tool for studying infrared waves in the Universe. Although the high altitude location provides clearer skies and less interference from the atmosphere, building an observatory on a high mountain poses enormous difficulties and challenges. However, despite the difficulties, the new observatory opens up broad research prospects for astronomers. ... >>

Random news from the Archive

Hydrogen is the cheapest way to cut emissions 03.09.2021

Green hydrogen produced using clean energy will be the cheapest way to reduce steel industry CO2 emissions to zero by 2050. This assessment was given by the research organization Bloomberg NEF.

The production of "green" steel using hydrogen currently provides for premiums on the price. By 2050, the cost of the process is likely to be less than production based on metallurgical coal or natural gas, despite the construction of new plants, according to Bloomberg NEF.

Geography will be one of the main factors in evaluating the most cost-effective ways to produce green steel. In particular, a country with high supply can make hydrogen the main fuel for steel production, while a country with developed hydroelectric power or other "clean" energy sources can electrify steelmaking using molten oxide electrolysis.

Other technologies that could contribute to the decarbonization of steel include carbon capture and storage technologies, alternative iron making processes, and carbon offsets.

"The cost of many of these technologies could come down due to economies of scale and greater efficiency," Bloomberg NEF stressed.

On the other hand, consulting firm McKinsey believes that steel production using hydrogen, carbon capture and storage technologies, carbon capture and use technologies can pay off no earlier than 2050. To do this, it is necessary to increase the scale of hydrogen production.

Other interesting news:

▪ Sugar water filter

▪ UAV for underground reconnaissance

▪ Samsung 3,2TB NVMe SSDs with 3D V-NAND Technology

▪ The composition of the intestinal microflora

▪ Synthetic human prion obtained for the first time

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site Assembling the Rubik's Cube. Article selection

▪ article Sukhomlinsky Vasily Aleksandrovich. Famous aphorisms

▪ Article Is milk the same? Detailed answer

▪ article carob tree. Legends, cultivation, methods of application

▪ article Simple logic probe. Encyclopedia of radio electronics and electrical engineering

▪ article Unusual photography. Chemical experience

Leave your comment on this article:

All languages of this page

Home page | Library | Articles | Website map | Site Reviews