Eternity expressed in mechanics. Gear Types Bevel Gears

In 1901 Elias Stadiatos was fishing with a group of other Greek divers off the coast of a small rocky island Antikythera located between the southern tip of the Peloponnese peninsula and the island of Crete. When examining the bottom at a depth of 43-60 meters, the diver discovered the wreck of a sunken Roman freighter 164 feet long. Items from the 1st century BC were on the ship. BC e .: marble and bronze statues, coins, gold jewelry, pottery and, as it turned out later, pieces of oxidized bronze that fell apart immediately after rising from the bottom of the sea.
The finds from the shipwreck were immediately studied, described and sent to National Museum Athens for display and storage. On May 17, 1902, the Greek archaeologist Spyridon Stais, studying the unusual fragments from sunken ships covered with marine growths that had lain at sea for up to 2000 years, noticed in one piece a gear wheel with an inscription similar to Greek writing. Near unusual object a wooden box was found, but it, like wooden planks from the ship itself, soon dried up and crumbled. Further research and thorough cleaning oxidized bronze made it possible to reveal several more fragments of a mysterious object. Soon a skilfully made gear mechanism made of bronze, measuring 33x17x9 cm, was found. BC e. - this is how the sunken ship was dated according to the pottery found on it. Many researchers believed that the mechanism was a medieval astrolabe - astronomical instrument for observing the movement of the planets, used in navigation (the oldest known specimen was the Iraqi astrolabe of the 9th century). However, it was not possible to come to a common opinion regarding the dating and purpose of creating the artifact, and soon the mysterious object was forgotten.

In 1951, British physicist Derek DeSolla Price, then professor of the history of science at Yale University, became interested in the ingenious mechanism from the sunken ship and began to study it in detail. In June 1959, after eight years of careful study x-rays subject, the results of the analysis were presented in an article entitled "The Ancient Greek Computer" and published in the Scientific American. With the help of x-rays, at least 20 individual gears were examined, including a semi-axial one, which was previously considered an invention of the 16th century. The side gear allowed the two rods to rotate at different speeds, similar to the rear axle of automobiles. Summing up his research, Price came to the conclusion that the Antikythera find represents fragments of the greatest astronomical clock, prototypes of modern analog computers. His article was met with disapproval in the scientific world. Some professors refused to believe in the possibility of such a device and suggested that the object must have fallen into the sea in the Middle Ages and accidentally ended up among the wreckage of a shipwrecked ship.

The main fragment of the Antiker mechanism.

Fragment of the Antiker mechanism.

G. Price published the results of more complete research in a monograph titled "Greek Instruments: The Antikythera Mechanism - The Calendar Computer 80 BC". In his work, he analyzed X-rays made by the Greek radiographer Christos Karakalos and gamma radiography data obtained by him. Price's further research showed that the ancient scientific instrument actually consists of more than 30 gears, but most of them are not fully represented. Nevertheless, even the surviving fragments allowed Price to conclude that when the crank was turned, the mechanism should have shown the movement of the Moon, the Sun, possibly the planets, as well as the rise of the main stars. According to the functions performed, the device resembled a complex astronomical computer. It was a working model. solar system, once located in wooden box with hinged doors that protected the inside of the mechanism. The inscriptions and arrangement of the gears (as well as the annual circle of the object) led Price to the conclusion that the mechanism is associated with the name of Geminus of Rhodes, a Greek astronomer and mathematician who lived around 110-40 years. BC e. Price decided that the Antikythera mechanism was designed on the Greek island of Rhodes, off the coast of Turkey, possibly even by Geminus himself, around 87 BC. e. Among the remains of the cargo with which the wrecked ship sailed, jugs from the island of Rhodes were indeed found. Apparently, they were taken from Rhodes to Rome. The date when the ship went under water, with a certain degree of certainty, can be attributed to 80 BC. e. The object was already several years old at the time of the crash, so today the date of creation of the Antikythera mechanism is considered to be 87 BC. e.
In this case, it is possible that the device was created by Geminus on the island of Rhodes. This conclusion seems plausible also because Rhodes in those days was known as a center of astronomical and technological research. In the II century. BC e. the Greek writer and mechanic Philo of Byzantium described polybolos that he saw on Rhodes. These amazing catapults could fire without reloading: on them, two gears were connected by a chain, which was set in motion with the help of a gate (a mechanical device consisting of a horizontal cylinder with a handle, thanks to which it could rotate). It was on Rhodes that the Greek Stoic philosopher, astronomer and geographer Posidonius(135-51 BC) managed to reveal the nature of the ebb and flow. In addition, Posidonius quite accurately (for that time) calculated the size of the Sun, as well as the size of the Moon and the distance to it. The name of the astronomer Hipparchus of Rhodes (190-125 BC) is associated with the discovery of trigonometry and the creation of the first star catalog. Moreover, he was one of the first Europeans who, using data from Babylonian astronomy and his own observations, explored the solar system. It is possible that part of the data obtained by Hipparchus and his ideas were used to create the Antikythera mechanism.
The Antikythera device is the oldest extant example of complex mechanical technologies. Application gear wheels clocks more than 2000 years ago cause the greatest astonishment, and the skill with which they were made is comparable to the art of watchmaking in the 18th century. AT last years several working copies of the ancient computer were created. One of them was made by the Austrian computer specialist Allan George Bromley (1947-2002) from the University of Sydney and watchmaker Frank Percival. Bromley also took the clearest x-rays of the object, which formed the basis for a three-dimensional model of the mechanism by his student Bernard Garner. A few years later, the British inventor, author of the orrary (a desktop demonstration mechanical planetarium - a model of the solar system), John Gleave, designed a more accurate model: on the front panel of the working model there was a dial that displayed the movement of the Sun and Moon along the zodiac constellations of the Egyptian calendar.

Another attempt to investigate and recreate the artifact was made in 2002 by Michael Wright, Curator of the Mechanical Engineering Department of the Science Museum, together with Allan Bromley. Although some of Wright's findings differ from those of Derek DeSol Price, he concluded that the mechanism is even more amazing invention than Price expected. Justifying his theory, Wright relied on x-rays of the subject and used the method of the so-called linear tomography. This technology allows you to see the object in detail, considering only one of its plane or edge, clearly focusing the image. Thus, Wright was able to carefully study the gears and establish that the device could accurately simulate not only the movement of the Sun and Moon, but also all the planets known to the ancient Greeks: Mercury, Venus, Mars, Jupiter and Saturn. Apparently, thanks to the circles placed on front panel artifact to the bronze marks that marked zodiac constellations, the mechanism could (and quite accurately) calculate the position known planets for any date. In September 2002, Wright completed the model and it became part of the "Ancient Technologies" exhibit at the Technopark of the Museum of Athens.
Many years of research, attempts to reconstruct and various assumptions have not given an exact answer to the question: how the Antikythera mechanism worked. There were theories that it performed astrological functions and was used to computerize horoscopes, was created as an educational model of the solar system, or even as an elaborate toy for the rich. Derek De Solla Price considered the mechanism to be evidence of tradition. high technology metalworking among the ancient Greeks. In his opinion, when Ancient Greece fell into decay, this knowledge was not lost - it became the property of the Arab world, where similar mechanisms later appeared, and later created the foundation for the development of watchmaking technology in medieval Europe. Price believed that at first the device was in the statue, on a special board. The mechanism may once have been located in a structure similar to the stunning octagonal marble tower of the winds with a water clock located on the Roman Agora in Athens.
Research and attempts to recreate the Antikythera mechanism forced scientists to look at the description of devices of this type in ancient texts from a different point of view. Previously, it was believed that references to mechanical astronomical models in the works of ancient authors should not be taken literally. It was assumed that the Greeks possessed a general theory, and not specific knowledge in the field of mechanics. However, after the discovery and study of the Antikythera mechanism, this opinion should change. Roman orator and writer Cicero who lived and worked in the 1st c. BC e., that is, during the period when the shipwreck occurred at Antikythera, tells about the invention of his friend and teacher, the previously mentioned Posidonius. Cicero says that Posidonius created a device the other day,<которое при каждом обороте воспроизводит движение Солнца, Луны и пяти планет, занимающих каждые день и ночь в небе определенное место>. Cicero also mentions that the astronomer, engineer and mathematician Archimedes from Syracuse (287-212 BC),<по слухам, создал небольшую модель Солнечной системы>. The speaker's remark that the Roman consul Marcelius was very proud of having a model of the solar system designed by Archimedes himself may also be related to the device. He took it as a trophy in Syracuse, located on the east coast of Sicily. It was during the siege of the city, in 212 BC. e., Archimedes was killed by a Roman soldier. Some researchers believe that the astronomical instrument recovered from the shipwreck off Antikythera was designed and built by Archimedes. However, the only thing that is certain is that one of the most amazing artifacts ancient world, a real Antikythera mechanism, is today in the collection of the National Archaeological Museum in Athens and, together with a reconstructed example, is part of its display. Copy ancient device also exhibited at the American Computer Museum in Bozeman (Montana). The discovery of the Antikythera mechanism unambiguously called into question the conventional wisdom about the scientific and technological achievements of the ancient world.

Recreated Antikythera Mechanism.

Reconstructed models of the device proved that it performed the functions of an astronomical computer, and Greek and Roman scientists of the 1st century. BC e. quite skillfully designed and created complex mechanisms, which for a thousand years had no equal. Derek De Solla Price observed that civilizations with the technology and knowledge needed to create such machines could build almost anything they wanted. Unfortunately, most of what they created has not been preserved. That the Antikythera mechanism is mentioned so little in the ancient texts that have come down to our time proves how much has been lost from that important and amazing period. European history. And if it wasn't for the sea sponge hunters 100 years ago, we wouldn't have this proof of existence either. scientific achievements in Greece 2000 years ago.

Antikythera mechanism

This mysterious artifact is rightfully in the TOP-5 of the lost technologies of antiquity and in the top ten of the mysterious ancient artifacts. Antikythera Mechanism mechanical device, discovered in 1902 on a sunken ancient ship near the Greek island of Antikythera (Greek Αντικθηρα). Dated to around 100 BC. e. (perhaps before 150 BC).

The amazing find - some strange-looking details - along with numerous amphorae and statues, was placed in the National Archaeological Museum in Athens. It is possible that the fragments of the device, overgrown with limestone, at first could be mistaken for a piece of the statue. One way or another, the unique artifact was forgotten for exactly half a century.

In 1951, an English historian of science took up the study of the artifact. Derek de Solla Price. It was he who first suggested that the Aegean Sea the wreckage is parts of some mechanical computing device. He also conducted the first X-ray study of fragments of the mechanism and was even able to build its scheme. A 1959 Scientific American article by Price sparked interest in the ancient artifact. Perhaps because Price first dared to call the mechanism an "ancient computer".

The mechanism contained big number bronze gears wooden case, on which dials with arrows were placed and, according to reconstruction, was used to calculate the movement of celestial bodies. Other devices of similar complexity are unknown in Hellenistic culture. It uses a differential gear, which, as previously believed, was not invented until the 16th century. With the help of differential transmission, the difference between the positions of the Sun and the Moon, which corresponds to the phases of the Moon, was calculated. The level of miniaturization and complexity is comparable to mechanical watch XVIII century. Approximate dimensions of the mechanism assembly 33x18x10 mm.

The mystery remains how the Greeks at that time did not have necessary knowledge and, most importantly, technology, were able to create such a complex device. For example, for the manufacture of gears, it was first necessary to master the technique of metal processing and use a lathe, albeit the simplest, but still.

In 1971, a complete scheme of the Antikythera mechanism was drawn up, consisting of 32 gears.

However, despite all attempts at research, the device remained a mystery to mankind even long years. So far, modern scientists have not taken up his research.

In 2005, the Greek-British Antikythera Mechanism Research Project was launched to study the Antikythera mechanism.

In order to restore the position of the gears inside the mineral-coated fragments, they used computed tomography, using x-rays allowing to make volumetric maps of hidden content. Due to this, it was possible to determine the relationship of individual components and calculate, if possible, their functional affiliation.

On July 30, 2008, the final report on the results of the study was announced in Athens. So, scientists have found out the following:

1. The device could perform addition, subtraction and division operations. From this it follows that before us is something like an ancient calculator.
2. The Antikythera mechanism is able to take into account the elliptical orbit of the Moon's motion using a sinusoidal correction (the first anomaly of Hipparchus' lunar theory) - for this, a gear with a displaced center of rotation was used.
3. The reverse side of the mechanism, badly damaged, was used to predict solar and lunar eclipses.
4. The text on the device is ordinary instruction for operation.

The number of bronze gears in the reconstructed model has been increased to 37 (actually 30 survived).

But the device had another purpose, which the researchers learned about only in 2006. Detailed study results of a CT scan of the object showed that there are marks on the body of the Antikythera Mechanism, which can be used to calculate one more time parameter - periods of holding Olympic Games.

In 2010 an Apple engineer Andrew Carol With the help of the Lego constructor, he created an analogue of the Antikythera mechanism. This model, consisting of the elements of the designer LEGOTechnics. It took 1,500 cubes and 110 gears to assemble the mechanism, and it took 30 days to design and build it.

The famous Swiss watch company Hublot this year released a wrist version of the Antikythera movement. This grandiose device is an adorable replica of an original ancient device. Hublot's Antikythera Caliber 2033-CH01 hand-wound movement, 38.00 mm long, 30.40 mm wide, 14.14 mm thick, consists of 495 parts, on 69 jewels, with a balance frequency of 21,600 vibrations per hour (3 Hz ), power reserve of 120 hours (5 days), functions of indication of hours, minutes, seconds (on a flying tourbillon), phases of the moon. In addition, it displays the signs of the Zodiac, the Egyptian calendar, the four-year ancient Greek calendar (Olympic Games cycle), the Callipic cycle (4 x 235 months), the Saros cycle (223 months) and the Exeligmos cycle (3 x 223 months).

Materials used in preparing the article:
Wikipedia - the free encyclopedia
and site

Imagine a gear. Most likely, a jagged circle has been drawn in your imagination, transmitting its movement to another similar gear. They can be big or small, but in your imagination they are all circles, right? Today I will show you gears that will break your brain. Get ready!

cube gears

This part is designed and 3D printed by the folks at Stratasys. By the way, it is interesting that it comes out of the printer already in assembled. The interacting parts are habitually rounded, but outwardly the whole system resembles a cube. He doesn't know how to do anything useful, but he looks cool.

spiral gear

Instead of the usual round shape, this gear bends in the form of a so-called. Golden spirals. As in the previous case, there is no practical use for this part, but it has one interesting feature: if one gear rotates at a constant speed, then the second one will either accelerate or slow down. Perhaps this can be applied somewhere.

oval gears

This type of gear has found its way into some devices, such as a mechanical hydrometer. As a result of the T-shaped interaction of the two gears, sufficient space is formed between them. If it is sealed, then water can be passed through it, and, taking into account the number of revolutions of the gears, calculate the volume of water that has passed. Conveniently!

Spherical gears

The author of this invention is Oskar van Deventer, who uploads many videos on his YouTube channel about interesting designs. Distinctive feature This transmission is the fact that its axles can be rotated 180°, while the system will continue to work. At this stage, the design has not yet been perfected, but it can already find many applications.

bean gears

It is difficult to say why they were made that way. Perhaps, as in the case of a helical gear, they are able to sharply increase and decrease the speed of their rotation, as a result of which they find application in the design of pumps.

alien gears

It is simply impossible to describe the shape of these gears in words, however, it cannot be denied that they work in the same way as any ordinary ones. The most interesting is the process of making these parts, so I recommend watching this video.

Round gear inside an oval gear

Yes, the internal gear here seems relatively ordinary, but there are teeth only on a small part of it. At that time, due to the presence of an oval gear, a rack and pinion mechanism is created.

The essence of the design is that the endless rotation of a round gear can be turned into movement in a straight line.

Rectangular gears

Another interesting mechanism without a known field of application is three parts, the interaction of which demonstrates a mathematical phenomenon called "Borromean Rings". Naturally, in this case, the rings are replaced by rectangles. Interesting and informative.

Spherical gear in vacuum

A small motor drives a large round gear, which, in turn, activates this whole incomprehensible mechanism. It is somewhat reminiscent of a complicated transmission from the first paragraph, located in a gyroscope. Naturally, it will not be possible to find the application of this transfer, but we must give the author his due: he did a great job, and his mechanism is capable of breaking the brain.

donut gear

Another piece of art featuring donut-shaped connected gears driven by a piece running through the center of the structure. A good replacement for the perpetual pendulum, not everyone has this!

Magic gears

Another invention by Oscar Van Deventer, this time with a little bit of magic. The outer two gears rotate counterclockwise and the center gear rotates clockwise, however, if you turn the central gear over, all three will begin to rotate counterclockwise in the same direction. How so? Maestro demonstrates this in his video.

While the gear wheel rotates in one direction, the pawl slides over the teeth of the wheel, jumping from tooth to tooth. When the gear changes direction, the pawl rests against one of the teeth, preventing the gear from turning.

Ratchets are often used in applications where rotational or translational movement is required in only one direction.
Ratchets are found in clocks, jacks, and lifting devices.

A mechanical device consisting of an eccentric attachment to a rotating shaft, shaped to provide the required reciprocating linear motion of another part.

Usually cam mechanisms used in hubs, electric toothbrushes, car engine camshafts.

Climbers, using spring-loaded cams, firmly fix a device for a safety rope in a rock crevice.

Gear

form gear wheels, engaging and capable of effectively transmitting force and motion.

Leading A gear wheel is a wheel that rotates under the influence of an external force, such as a hand or a motor. Drive wheel transmits external force on the slave wheel, which also begins to rotate.

With help gears you can change the speed, direction of movement and force.

You can't increase both force and speed at the same time.

To get the ratio of two gears in mesh, you need to divide the number of teeth on the driven gear by the number of teeth on the drive gear.

Gears don't have to be round. There are square, triangular and even elliptical gears.

puzzles

Task 1

If the left gear turns in the direction indicated by the arrow, in which direction will the right gear turn?
1. In the direction of arrow A.
2. In the direction of arrow B.
3. I don't know.

Task 2

In what direction will the gear wheel move if the handle on the left is moved up and down in the direction of the dotted arrows?
1. Back and forth along the arrows A-B.
2. In the direction of arrow A.
3. In the direction of arrow B.

Task 3

Which gear rotates in the same direction as the drive gear? Or maybe none of the gears rotate in this direction?

3. None of them rotate.

Task 4

Which of the axes, A or B, rotates faster, or do both axes rotate at the same speed?
1. Axis A rotates faster.
2. Axis B rotates faster.
3. Both axes rotate at the same speed.

Task 5

Which gear rotates faster?

GEAR TYPES

In essence, gears are devices that transmit rotational motion from one axis to another. Some types of gears can also perform translational movements. There are dozens various types gears in the industry, only some of which are shown here.

CYLINDRICAL GEARS

Cylindrical gears run on shafts whose axes are parallel

One of side effects pairs of spur gears is that the output axis rotates in the opposite direction from the input axis, an effect that can be clearly seen in the animation

BEVEL GEARS

Bevel gears operate on axes that are not parallel. Bevel gears can be made specifically for axles at almost any angle

worm gears

A worm gear (or screw) can be thought of as a single tooth gear

Worm gears have some special properties that make them different from other gears. First, they can achieve very high gears in a single movement. Because most worm gears have only one loaded tooth, the gear ratio is simply the number of teeth per gear connection. For example, a worm gear pair paired with a 40- toothy the helical gearbox has a ratio of 40:1. Second, worm gears have much higher friction (and lower efficiency) than other types of gears. This is because the tooth profile of the worm gears is constantly sliding over the teeth of the mating gears. This friction gets higher, the greater the load on the transmission. Finally, a worm gear cannot work backwards. In the animation below, the worm gears on the green axle are driven by the blue gears on the red axle. But if you turn on the red axle as the leading one, then the worm gears will not work. This transmission property can be used to stop - block things in a certain place, without rolling back, such as a garage door.

LINEAR GEARS

It is a means of converting the rotational motion from the axis of rotation or pinion into the translational motion of the rack. The gear rotates and pushes the rack forward as the gear teeth move in it. Regulated for example, fewer teeth on the drive gear and more on the rack. the movement in the racks will be proportional to the number of teeth on the gear

DIFFERENTIAL GEAR

Differential- this is a mechanical device that transmits torque from one source to two independent consumers in such a way that the angular speeds of rotation of the source and both consumers can be different relative to each other. Such transmission of torque is possible due to the use of the so-called planetary mechanism. In the automotive industry, the differential is one of the key parts of the transmission. First of all, it serves to transmit torque from the gearbox to the wheels of the drive axle.

Why does this require a differential? In any turn, the path of a wheel on an axle moving along a short (inner) radius is less than the path of another wheel on the same axle traveling along a long (outer) radius. As a result, the angular velocity of rotation of the inner wheel must be less than the angular velocity of rotation of the outer wheel. In the case of a non-driving axle, this condition is quite simple to fulfill, since both wheels may not be connected to each other and rotate independently. But if the axle is driving, then it is necessary to transmit torque to both wheels simultaneously (if you transmit torque to only one wheel, then the ability to drive a car according to modern concepts will be very poor). With a rigid connection between the wheels of the drive axle and the transfer of momentum to a single axis of both wheels, the car could not turn normally, since the wheels, having equal angular velocity, would tend to go the same way in the turn. The differential solves this problem: it transmits torque to the separate axles of both wheels (half shafts) through its planetary gear with any ratio angular velocities half shaft rotation. As a result, the vehicle can move and steer normally both in a straight line and in a turn.

TRANSMISSION WITH GEAR CHANGE

The driving ring, in combination with a pair of intermediate gears that are not fixed on their axis, have the function of turning the gears on and off.

The animation shows work gears, to disable or or in order to ensure the engagement of the gears with the help of an intermediate gear. The moving rings are shown in red. ,the axles are connected to a gray axle with white discs that slides on the grooves of the main axle. The driving white ring rotates with the axles. At first , the moving ring is disabled because the dark gray and green gears are not engaged. The moving ring engages with the green and thereby sets the blue gear in motion. The moving ring does not use teeth, but uses four tapered fingers, there is a significant gap between the ring and the fingers. Which allows you to connect the ring at idle or when the gears rotate with different speeds

ADJUSTABLE ROTOR