Smooth move. How does multi-link suspension work? The influence of vibrations and vibrations on humans

Smooth ride, you say? And you argue about it on forums? How do you measure it, this smoothness - with a speedometer? But it’s okay, we’ll show you how! Russian TopGear was lucky: we participated in the most intelligent experiment to study the operation of the suspension

We were invited to a secret training ground here. Since ancient times, vehicle suspensions have been tested on it for the top officials of the state: the coating made of special paving stones here accurately imitates all the unevenness of Red Square and Vasilievsky Spusk. Of course, not all of us were invited, but only the most sensitive ones. Therefore, the youngest ones went: 72-year-old Novatsky and 92-year-old Zhutikov. We gave them jackets in festive colors for the trip. Well, you never know - what if they offer to host a mock parade?

The secret training ground was in the center. Early in the spring morning, our carefully but poorly shaven youth arrived at the testing site. A couple of executive cars were waiting for her there: the latest BMW 7-Series and Jaguar XJ L. One car was white, the other black. As we soon learned, there was a clearly defined scientific charge to all of this.

It turns out that vibrations in the cabin are most accurately identified using chess, the favorite game of the Kremlin leaders. Two testers (they were nicknamed Soso and Ilyich at the training ground) sit in the back seat, place a board with pieces between them and smoothly make moves. At the same time, the car passes calibrated paving stones at speeds from 20 to 90 km/h, makes a series of left and right turns, and also accelerates and brakes with varying intensity. Both cars are tested this way in turn. The experiment is recorded by cameras mounted at different points in the cabin. By the way, you can also watch videos from these cameras.

“And what ultimately determines the smoothness of the ride?” – you ask, not unreasonably. There are three main measuring markers. The first is whether the riders were seriously injured. Did they have new bruises and contusions, did a rook or - God forbid - a bishop get stuck in natural holes.

The second is where the board ended up: how far it has shifted from the central position, and whether it has flown to the front of the cabin. They say that they tried to carry out such tests at AvtoVAZ, but they were a fiasco: the boards often flew outside the cars and even outside the test site. But since then, chess has become much better played in the vicinity of Tolyatti.

The third parameter is the scattering of figures throughout the cabin. For example, when braking sharply in a BMW, the white queen, instead of square d1, ended up under the gas pedal. In “Jaguar”, a rook from square h1 flew into the front armrest and got stuck in it according to all the rules of classical castling.

Our experts spent two hours testing the paving stones. During this time, they were unable to complete a single game, since the pieces independently moved around the board and the interior, regardless of the will of the grandmasters. In such situations it is impossible to enjoy the game. Therefore, we will not talk about the Philidor Defense and the middlegame here. We'll report back on the test results. Which car is softer? Where is the most comfortable place to be in the back?

During the experiment, irrefutable data was obtained: the leader in ride smoothness is BMW. Jaguar is noticeably tougher. The figures in it begin to walk on their own at walking speeds. However, the Jaguar also has strengths that prevented it from running dry: it has more legroom. And during sharp braking, its driver is protected from flying figures and boards much better than a BMW driver. So if you don't like shaking, have short legs and a lot of spare drivers, take a BMW. In all other cases, your choice is Jaguar! True, no other cars of this class were presented at the secret tests. Therefore, we can definitely judge only the couple that we experienced ourselves.

It should be noted that it is impossible to actually knock down the figures by shaking on the paving stones. Keep it at least 20, at least 200 km/h - they only move a little on the board. In Jaguar, this movement occurs more energetically. But for at least one piece to fall - no. That's how perfect modern pendants are! Overloads from acceleration and braking are much higher. Just be sure to hold the board with both hands! To our particular pleasure, it turned out that we gave out multi-colored jackets to the experts for a reason, and it was not without reason that the cars were different colors.

The final test was a comparison test. The same chessboard with pieces was attached to the side of one of the cars with a special device. An expert in a dark jacket got into a black car, and a lighter one into a white car. And they played with pieces of the corresponding colors. Special purpose drivers synchronously accelerated cars to 250 km/h, and grandmasters led the game leaning out of the windows.

This test seemed to us quite controversial, although the most effective. During it, experts also assessed the dependence of shaking on tempo. And then both cars performed flawlessly - the board did not move. The figures, however, were already blown away at 40 km/h, which allowed the experts to simply look out the window most of the time. Full-time testers admitted that they love this test most of all - time and salary go by, and you just sit and watch how blacks fly after whites.

But for us, from this day on, the concept of “smooth running” is not an empty phrase. We saw how professional testers work and experienced a clear difference between machines of the same class. So stop worrying about it: it won’t help you when choosing a car.

IDEA: ALEXEY SHARAPOV, VITALY TISHCHENKO
WHITE GRANDMASTER: KONSTANTIN NOVATSKY, WHITE CAR: BMW 730D
BLACK GRANDMASTER: ALEXEY ZHUTIKOV, BLACK CAR: JAGUAR XJ L
TEXT: ALEXEY ZHUTIKOV
PHOTO: SERGEY KRESTOV

Our Community has collected excellent material about painting and decoupage of watches.

But we missed one point - installation of the clock mechanism.

Useful information about watch movements:

The watch movement case has the following dimensions: width: 56 mm, height: 56 mm, thickness: 16 mm, rod diameter: 8 mm (diameter of the hole for the rod in the dial).

The stem is the part of the mechanism that is threaded through the hole in the center of the dial. It consists of a threaded part, a seat for the hour hand, a seat for the minute hand and a hole for installing the second hand.

The threaded portion of the stem must be at least 2mm larger than the thickness of the dial. This is necessary in order to secure the mechanism (install the washer and tighten the nut).

For example: 16/9 rod means that the height of the threaded part = 9 mm. This means that the thickness of the dial should be no more than 7 mm so that the mechanism with such a rod can be fixed.

In the name of the watch movement, the first indicates the overall size of the stem, and the second indicates the size of the threaded part (12/6, 16/9, 18/12, etc.)

Clock mechanisms differ in the movement of the second hand:

The watch can be hung from the metal loop:

The size of the arrows is indicated from the center of the hole to the tip of the arrow:

There is a protective film on the arrows, which must be removed during installation:

Installing the clock mechanism and hands on the workpiece:

1. Install the fastening loop onto the mechanism

2. Insert the mechanism rod into the hole on the product. Place the washer and tighten the nut.

3. Place the arrows on the stem: first the hour hand, then the minute hand and the second hand (it must be inserted into the hole). In order not to damage the hands when fitting them onto the stem, it is recommended to use a tube of the required diameter. If you don’t have a special tool at hand, you can use a simple ballpoint pen.

It's been a while since I've done a watch review. Either headphones, then knives, or flashlights - it's time to write something about watches;)
A little history.
Bulova is an old American watch company that dates back to 1875 (yep, 140 years this year). The brand was very popular in the 50s and 60s, and is still quite famous for its Accutron line with a tuning fork mechanism.
In 2008, the company was acquired by Citizen and did not take over completely, but left it as a manufacturer of several lines of watches under the Bulova brand.

The Bulova Precisionist.
The Precisionist is a very interesting line that surprised many watch fans when it went on sale.
The surprise is associated with the use of temperature-compensating quartz in some models, as well as with the “floating” second hand. In principle, the technology of a “floating” hand is not new; for example, it is found in the Seiko Spring Drive, which were an order of magnitude more expensive.
According to Bulova, the accuracy of a quartz watch depends on two things: changes in ambient temperature and the vibration frequency of the quartz resonator. Thermal compensation combats the consequences of temperature changes, but with vibration frequency everything is much more interesting.
Conventional quartz watches make one tick per second, 60 per minute, 3600 per hour, this is due to the simplicity of the design, given that the standard frequency of a quartz resonator in a watch is 32 kHz:


Seiko Monster with six ticks per second goes more smoothly:


The mechanics on the ETA 2824-2 make it even smoother with eight ticks per second:


The previously mentioned Seiko Spring Drive at a five-second interval looks like this:


Three of the four models mentioned above are manual.
As for Bulova, with a stated quartz frequency of 262 kHz and sixteen ticks per second, it looks like this:

Speaking of accuracy.
Bulova claims a maximum accuracy of 10 seconds per year in this line.
Several years ago, on the watchuseek forum, one stubborn friend took accuracy measurements every week for a year. While he wore it for 20 weeks, the watch ran away by 1 second; for the remaining 32 weeks, the watch lay there and ran away by 8 seconds during this time. those. claims of 10 seconds/year accuracy are well deserved.

accuracy graph

So, Bulova Precisionist Claremont 96B128
Round watch, 42.2mm in diameter and 12mm thick, polished steel case, mineral glass, month date display, lume on the hour and minute hand, 3ATM water resistance, 78g weight.
By the way, the shape of the glass is quite interesting - it is slightly dome-shaped in one of the projections. The downside is that the glass is still mineral and not sapphire.
For this kind of money, the strap should be leather, but there are some doubts. In any case, it’s too hard and thick for my liking, so a good leather strap of the same brown color and a metal bracelet will replace it.
The winding head is 3-position: in the middle position the date is set, in the extreme position the time is set with a stopsecond.

and some photos

Vehicle vibrations affect almost all the basic operational properties of the car: comfort and smoothness, stability, handling and even fuel consumption.
Fluctuations increase with increasing speed and engine power; the quality of the road has a significant influence on fluctuations.
Vibrations and vibrations in cars are a source of noise. Oscillations, vibrations and noise have a harmful effect on the driver, passengers and the environment.
Norms and standards have been established that determine the permissible levels of vibration, vibration and noise of vehicles. The quality and price of a passenger car depend on these indicators.
Vehicle tests to determine the level of vibrations, vibrations and noise are carried out in laboratories and on special roads at test sites.
It is impossible to make a passenger car in which there are no vibrations, vibrations and noise, just as it is impossible to build a perpetual motion machine. However, it is quite possible to create a car with minimal levels of vibration, vibration and noise.

Vibrations occur primarily when the wheels interact with the road surface. As a result of deflection of pneumatic tires and deformation of the suspension, the wheels and body undergo complex vibrations. The vibrations of the wheels determine the stability and controllability of the car. Body vibrations directly determine the smoothness of the ride.
Oscillations along the longitudinal axis appear during braking and acceleration, but cannot be decisive for the smoothness of the ride. Horizontal vibrations along the transverse axis of the body (lateral vibrations) are possible only due to the lateral deformation of the tires. As a result of the use of wheel suspension, the body performs mainly vertical, longitudinal-angular and transverse-angular vibrations. The listed vibrations determine the smoothness of the car.
Assessing the smoothness of a car. What is ride comfort and why is it given special attention when designing, operating and comparatively evaluating various passenger cars? Of course, the smoothness of the ride depends not only on the design of the car and its suspension, but also on the quality of the road surface and speed. The following definition can be given: smoothness is the property of a car to protect the driver, passengers and transported cargo from vibrations and vibrations, shocks and shocks resulting from the interaction of the wheels with the road.
The very concept of smooth running arose a long time ago. Carriage masters skillfully made the suspension of horse-drawn carriages, achieving a highly smooth ride. The suspension of ancient carriages was very soft, had long springs with large deflection and low rigidity. It is curious that in these parameters it was superior to the wheel suspensions of many modern cars. At the beginning of their journey, cars had far from record speeds among land vehicles. For example, in 1894, during the first Paris Rouen automobile race, cars with Daimler engines showed an average speed of 20.5 km/h. However, during the first 10...15 years of the car’s existence, its speed increased sharply, exceeding 100 km/h.
The first world speed records were held by cars with electric motors (EVs). In 1898, the electric car of Charles Jeantot (France) with two electric motors (total power 36 hp) set the world's first absolute speed record of 63.149 km/h, and in 1899 the electric car of the Belgian Camille Genatzi, Always Dissatisfied (electric motor power 40 l. s.) exceeded the hundred-kilometer barrier of 105.876 km/h. However, electric car records did not last long. In 1902, the Frenchman Henri Fournier drove a Mercedes car with a 60 hp gasoline engine. raised the absolute record to 123.772 km/h.
Passing the speed limit of 100 km/h by cars was not without casualties. At the Paris Madrid race in 1903, disasters occurred due to high speed (more than 100 km/h), bad roads, dust, and poor ride quality, and the French government banned the continuation of the race. The cars were transported by horse-drawn vehicles to the railway.
In 1904, young Henry Ford reached a speed of 147 km/h in his Arrow car.
The comfort and smooth running of the first record-breaking cars can be judged by the Ford Strela, whose drive wheels were rigidly attached to the frame, and the engines did not have mufflers. Why the driver did not fly out of his seat, holding only the control handle, is absolutely unclear. The most important thing was speed.

A speed of 205.443 km/h in 1906 was achieved in a rocket racing car from the American company Stanley. The car had a steam engine with a power of 150 hp. This was the “swan song” of steam cars. In 1937, on the Auto-Union car, all wheels of which had independent suspension, with an engine power of up to 640 hp. a speed record of 406.3 km/h was set.
What inventions and improvements in car design made it possible to increase speed so quickly? The main ones were increasing engine power, using streamlined body shapes, improving steering and brakes, and, of course, the most important role was played by the invention of pneumatic tires and the use of independent car wheel suspension.
With such a suspension in the early 20s. The Lambda car began to be produced in Italy. In the USSR, the first passenger car with independent suspension was the famous GAZ M-20 (Pobeda). The use of independent suspension not only saved the car from dangerous vibrations of the steered wheels (the shimmy phenomenon), but also contributed to a significant improvement in the smoothness of the ride. Nowadays, further improvement of the ride, stability and controllability of a passenger car is unthinkable without the use of controlled (adjustable) suspension systems.
Obviously, smoothness needs to be quantified. However, this is not a simple task, in solving which you cannot rely only on your own impressions. The impressions of the driver and passengers about the smoothness of the ride may vary depending on many circumstances: their age, health, etc. You cannot rely on a subjective assessment.
It has long been known that cars with soft suspension have the best ride. The stiffness of springs can be reduced by increasing their deflection, and therefore increasing the wheel travel relative to the body. It is not always possible to make the suspension soft and long-travel. An obstacle to increasing wheel travel is not only the need to increase the size of the wheel housings of the body, but also the difficulties associated with the placement of transmission devices, brakes and steering.
Static is the deflection of springs (or spring settlement) when the car is stationary. By the magnitude of the static deflection, you can evaluate the stiffness of the suspension and the smoothness of the ride.
The simplest and most accessible indicator of smoothness is the frequency of natural vibrations of the car body. Experience shows that if the frequency of these oscillations lies within the range of 0.5... 1.0 Hz, then the machine has a highly smooth ride. (It is interesting to note that the indicated frequencies coincide with the frequency of shocks that a person experiences when walking at a speed of 2... 4 km/h.)
While in the back of a passenger car, a person experiences two main types of complex oscillatory movements: relatively slow oscillations with large amplitudes and fast oscillations with small movements. You can protect yourself from vibrations with small movements using seats, rubber supports, gaskets, vibration isolators and other devices. To protect against vibrations with low frequencies and large amplitudes, elastic wheel suspensions are used.

Vibration load standards are set so that on the roads for which the car is intended, vibrations of the driver and passengers do not cause them discomfort and rapid fatigue, and vibrations of cargo and structural elements of the car do not lead to damage. The vibrations that occur when a car moves, caused by road unevenness, affect not only the smoothness of the ride, but also a number of other operational properties. Thus, when operating trucks on roads with unsatisfactory surface conditions, the average speed decreases by 40...50%, the mileage between repairs - by 35...40%, fuel consumption increases by 50...70%, and the cost of transportation - by 50...60%. A car is an oscillatory system, which includes inertial, elastic and dissipative elements. Inertial masses include the masses of the body, axles with wheels, people and cargo. There are sprung masses (mass of the body, cargo and passengers) and unsprung masses (mass of axles and wheels). Elastic and dissipative elements form the basis of a vehicle’s vibration protection system. This system includes: suspension, tires, driver and passenger seats. Suspension includes all structural elements connecting axles or individual wheels to the frame or body. In addition to elastic and dissipative elements, it includes guide devices that determine the kinematic characteristics of the movement of the wheels relative to the frame or body and ensure the transfer of forces and moments between them. The impact of road irregularities on the oscillatory system of a car causes vibrations of the masses and leads to a change in their kinetic energy. Elastic elements are designed to convert the energy of shocks and impacts created by road irregularities into potential energy of elastic elements. The purpose of dissipative elements is to dampen vibrations. They provide energy dissipation by converting mechanical vibration energy into thermal energy. The intensity of vibration damping depends on the amount of friction of the dissipative element (hydraulic resistance of the shock absorber, internal friction of tire elements and seats).