Rotor balancing. Crankshaft balancing in a garage: efficiency and guidance How to balance a shaft at home

The only way to further reduce the vibration of the internal combustion engine is to balance the unit. An in-line four-cylinder engine receives unbalanced forces that arise when the masses move, taking into account one or another crankshaft speed. The value of inertia depends on the volume of the internal combustion engine, with an increase in volume power plant inertia increases.

The balancing shaft is installed on in-line four-cylinder engines with a displacement of more than two liters. It should be noted that the installation of such shafts leads to a noticeable increase in the cost of the structure and is not particularly actively used on cars even in the middle price segment.

Balance shafts are installed in pairs. They are often located symmetrically on both sides of the crankshaft. The place of installation of the balance shafts most often becomes the crankcase of the engine so that the shafts are lower crankshaft ICE. It turns out that these shafts are under the crankshaft, and the oil pan becomes their place of installation.

The balance shafts are directly driven by the crankshaft. The drive implements the rotation of the balancing shafts in different directions.

The angular speed of rotation of the balancers is doubled. The drive can be made either separately by means of a gear reducer or chain drive, or as a combination of solutions. Torsional vibrations from the rotation of the shafts themselves, they are damped by a spring vibration damper, which is located in the drive sprocket of the balance shaft drive.

During operation and due to the design features of the drive balance shafts subject to severe stress. The most overloaded bearings, which are located in the opposite side of the drive. Takes their place rapid wear, which is manifested by additional noise and the appearance of enhanced vibrations. In the worst cases, a break may occur drive chain. An additional disadvantage is the selection ICE power, which is spent on the drive of the balance shafts.

Read also

Why does the engine vibrate idling. Causes of malfunction, diagnostics. Tips and tricks to reduce the level of motor vibrations.

Features and differences boxer engine from others piston internal combustion engines. The advantages of a boxer motor, the disadvantages of this design, the nuances of maintenance.

DYNAMIC BALANCE OF ROTORS ON THE MACHINE WITH ROCKING FRAME

Balancing the rotors is a procedure necessary if the rotating part of the machine is out of balance. In this case, during rotation, there is a shaking (vibration) of the entire machine. In turn, this can lead to the destruction of the bearings, the foundation and, subsequently, the machine itself. To avoid this, all rotating parts must be balanced.

The rotor itself is a rotating part, which is held during rotation by means of bearing surfaces in the supports (trunnions, etc.). The axis of the rotor is a straight line connecting the centers of gravity of the contours on the cross sections of the center of the bearing surfaces. There are several types of details:

Double support;

Multi-bearing;

Intersupport;

Console;

Two-console.

Distinguish balancing of rotors static and dynamic. The first is performed on prisms, the second when the part to be balanced is rotated.

Specialists of the company "KardanBalance" offer services for high-quality balancing of the rotor. Our centers are equipped modern equipment, which guarantees the accuracy of balancing. This is quite difficult to achieve, because it must completely coincide with the accuracy of the manufacture of the rotor. All work is carried out on stands own development, which give a balancing accuracy five times higher than the factory requirements!

In this section, you can get acquainted with the main technical information regarding the methods of dynamic balancing of the rotor (the method of exceptions, the method of B.V. Shitikov). Useful practical material that will give a basic understanding of the problem. What is hydraulic balancing, what is a wheel balancing machine and other information is clearly presented on our resource. You can also use our services, which include cardan repair, balancing of cargo wheels, crankshaft, etc. How much does balancing and other work cost is described in the "Services and Prices" section.

1. INTRODUCTION. BASIC CONCEPTS

When rotating m(mass) around a point (stationary) with w (angular velocity) F (centrifugal force inertia) of this mass:

(1.1)
Where and n - normal acceleration of the mass; is the distance from the axis of rotation to the center of mass. As the mass F moves, it will change direction and act (vibrate) on the supports and through them on the structures attached to the post.
D(imbalance) - a vector quantity that is equal to the product of the unbalanced mass and the eccentricity (radius vector of the center of mass). The value is measured in g/mm.

And the vectors " D" And " e" collinear quantities.

In vector form, the formula has the following form:

The vectors F and D turn out to be proportional to each other.

2. ROTOR UNBALANCE AND ITS MANIFESTATION

According to GOST 19534-74, a rotor is a body that, during rotation, is held in supports by its bearing surfaces. In automobiles, this can be a gear wheel, a pulley, an electric motor rotor, a drum, a crankshaft, etc.
If the masses are distributed in the rotor so that during rotation they cause loads in the supports, then it is called unbalanced. Moreover, there are 3 types of rotor unbalance:

• Static. At which the axis of rotation and the main axis of inertia are parallel. In this case, the pressure variables are equal to 0

• Dynamic. In which the main axis and the axis of rotation intersect or intersect, but not at the center of mass, because of this, imbalance occurs most often.
• Instant

In all cases of unbalance of the rotor, the forces of inertia of its masses create dynamic loads. They are eliminated by the redistribution of masses (by installing counterweights).

Dynamic balancing carried out using a special machine equipped with a swinging frame

3. Rotor balancing by elimination method

In order to determine the parameters of the mass (corrective) in the P plane, the rotor is installed on the machine and the eccentricity of the mass is assigned. A circle is outlined in the plane, and its center must coincide with the geometric axis of rotation. The radius is taken equal to the selected eccentricity. The circle is divided into 4 parts. We attach the mastic (plasticine) so that the center of the piece coincides with point 1. Let's bring the rotor into rotation and measure the amplitude of the oscillations. The indicator is recorded near point 1.

We transfer the mastic to point 2, accelerate the rotor and again fix its amplitude. Let's write it down. We fix the remaining 2 points.

We compare the amplitudes until they are the smallest. Point K, found by us, determines the final position of the corrective mass. The opposite point H is an unbalanced mass.

Now we begin to change the mass of the mastic into points K and measure the oscillations of the rotor. So we find the value of the corrective mass.

4. BALANCE OF THE ROTOR BY THE B.V. METHOD SHITIKOVA

Install the rotor on the frame and accelerate it. After that we fix the amplitude A 1 .

At point P 1 we will install an additional mass m g with eccentricity e g . At resonance, we fix the amplitude AS.

We rearrange the mass to the opposite point and fix the second amplitude. We denote points on the plane in accordance with the inequality under which the first amplitude is greater than the second.

By 3 amplitudes we build a parallelogram and find the fourth amplitude and angle

1

Using the formula, we determine the coefficient of proportionality of the mass

m= A g /D g = A g /( m g e g),

Determine the imbalance of masses

Now we set the value of the mass (corrective) from the equality of imbalances and find the desired eccentricity

D to \u003d D 1 e k \u003d D 1 /m k.

It remains to determine the points of installation of weights and test runs to determine the residual amplitude, as well as to evaluate the quality of balancing in the plane.

Doct =Aoct /m

In the company "KardanBalance" you can buy cardan shaft Chevrolet Niva, UAZ driveshaft, Mercedes Vito driveshaft, as well as components for other cars. We carry out not only the sale of spare parts, but also their subsequent installation.

All vehicle components must work properly to ensure it maximum performance. However, parts wear out over time. Therefore, they need to be periodically changed and, if necessary, balanced. This is especially true for the flywheel.

What is a flywheel?

The flywheel is the disk-shaped component of a car that connects to the crankshaft. Although it has virtually no moving parts, it is essential to the proper functioning of the crankshaft. Its main task is to create inertia for some parts of the car. In addition, it connects the starter and the shaft, which ensures the start of the engine.

This is a fairly massive element of the car, which does not allow the pistons to remain motionless. Due to its large mass, it allows you to easily start the movement of other mechanisms.

However, due to the high mass, one problem is created - balancing. If this element has a displaced center of gravity, then rotation leads to the appearance of additional forces. Displacement occurs for various reasons, whether it is marriage, wear of a part, or incorrect installation. However, it is important that these forces lead to vibration, which is extremely dangerous for car parts.

In this part of the car, even a slight vibration can lead to significant damage to parts. The destruction of the starter, crankshaft and other components is not the limit if this factor is neglected. Therefore, it is important to monitor the center of gravity of the flywheel and, if necessary, to balance.

Balancing basics

Balancing is the process by which the center of gravity returns to the geometric center of the flywheel. Especially often it is carried out after the procedure for lightening this part, which is often practiced by motorists. Balancing is extremely important, otherwise destructive forces can act on the engine.

There are several types of imbalance on the flywheel, among them:

• static;
• instant;
• dynamic.

In the static case, some kind of mass appears on the axis of the part. Because of this, the axis of the device is shifted relative to the axis of rotation, which leads to vibrations. In the instant, additional masses appear at the edges of the part. If the flywheel does not move, then vibrations do not occur, but during rotation they can manifest themselves extremely strongly. The last option is dynamic. It combines the previous types of imbalance.

Advice! To eliminate dynamic imbalance, wheel balancing is often carried out. It helps to avoid this effect.

Often, to eliminate such problems, the car is taken to the service. There, the flywheel is carefully balanced, returning the center of gravity to its original position. However, this procedure can be carried out without outside help, carrying it out at home. Difficulties are minimal here.

Do-it-yourself flywheel balancing

Most simple solution is static balancing. Although it can be done different ways, then one of the simplest will be used. It allows you to complete the procedure without special tools.

To begin with, it is important to determine the weight shift point. To do this, a metal bar is threaded through the center of the flywheel, which can withstand a similar weight without deformation. If it still has a shaft in its design, then you can use it for this task. Next, you need to take two straight supports and fix them in parallel.

Important! It is worth carrying out this procedure with a water level, because the slightest miscalculation can lead to erroneous conclusions in the diagnostic process.

Next, the flywheel is placed on these supports. After that, the heaviest side will move down, turning the axle. This will give an idea of ​​the approximate location of the center of gravity. By the way, for the same task, you can replace the direct supports with a vice, holding the shaft on which the part is located.

Although craftsmen recommend hanging weights for balancing, often excess metal is simply drilled out. The problem is that not only does this reduce the overall weight of the flywheel, but it can simply render the part unusable.

You can also balance by weight if the part has a bearing. The idea is the same, there are several weights and a flywheel at an angle. Gradually rotating and determining the lack of weight, you need to place loads until the part is completely balanced. Many consider this option more convenient, because the flywheel is not fixed anywhere and is constantly in limbo

Services are often dynamically balanced. given element. It is more reliable and faster, and the result is an absolute balance of the part. This approach is recommended to everyone, but for this you need to go to the service. It is almost impossible to carry out such a procedure on your own, because this requires a special stand with equipment. In addition, not only the flywheel is used here, but also the crankshaft and clutch.

So for independent holding works better fit static balancing. It allows you to quickly and quite well return the center of gravity to its place, using only improvised means. Although this is done faster and more accurately on the stand, such option is suitable for budget repairs.

And for a better understanding of the flywheel balancing procedure, it is recommended to watch this video. Shown here is a fixed part where you can define a center of gravity offset. This is the basis for further balancing procedures:

In every mechanism that performs rotational movements, due to mechanical impact or wear of components, an imbalance occurs, which manifests itself in the form of vibrations. If vibrations go through the body of the car with a set speed, then there is a possibility that an imbalance of the driveshaft has appeared. This problem can lead not only to the failure of the cardan, but the entire car, which will require significant material costs for its repair. Balancing can be done independently, or you can contact the service station.

If the cardan shaft vibrates, it is recommended that it be balanced immediately. Photo: cardan-garant.ru

Why balance the cardan shaft

Probably every motorist has heard about cardan balancing, but not everyone understands the need for it. The main function that the driveshaft of a car performs is to transmit torque.

A cardan shaft that is out of balance can affect the operation of other adjacent parts.

Premature wear occurs on the gearbox shank flange bearings and secondary shaft Checkpoint. In case of wear of the gearbox shank during driving, there may be emergencies, the consequences of which can be extremely undesirable.

The main causes of imbalance

There are many reasons for imbalance. They differ in their nature and other features. Among the most frequently encountered are the following:

1. The initial assembly of the driveshaft was poorly executed;
2. Non-observance of technology when performing fastening of parts. In the event that a balance has been found, then incorrectly fixed parts will soon loosen, after which balancing will be required;
3. The low quality of the materials used, improper hardening of the metal from which the cardan is made. Cardan shaft, which is made of metal with insufficiently high operational characteristics, will not withstand all static and dynamic loads;
4. Too much huge pressure. The imbalance appears even in cases where the car has not been used for some time;
5. Mechanical damage to parts that may occur as a result of an accident.

How to balance the propeller shaft yourself

The resulting vibration, which is observed as the speed of the car increases, cannot be ignored, at the first signs, actions must be taken to eliminate it. To perform balancing, you need to have some knowledge and experience.

In general, self-balancing is a simple process, although it can take quite a lot of time. Photo: static.imfast.com

To balance the shaft with your own hands, you need viewing hole, which you want to pre-drive the car. You also need to prepare several weights with different weights, which are used during wheel balancing. Instead, electrodes or pieces of lead may be suitable. To perform balancing, do the following:

1. Divide the cardan into 2 parts along the length;
2. Across conditionally divide it into 4 equal parts. If you possess big amount free time, gimbal can be divided into 8 or more parts;
3. To the surface of the first part you need to attach a weight of 30 grams. It must be attached securely, but with the possibility of subsequent dismantling;
4. Carry out a driveshaft test. To do this, you need to go to a flat section of the road and listen to see if the vibrations have decreased;
5. If the vibrations have not disappeared anywhere, you need to return to the garage and move the used weight to another section of the driveshaft. After that, re-test on the road.

The above actions must be performed until such time as you achieve the absence of vibrations in the car.

After minimizing vibration, the optimal weight of the weight to be used must be found by trial and error. Ideally, when correct selection its mass, vibration should disappear altogether.

After you have found the optimal weight of the weight, you need to firmly fix it. This can be done using electric welding. In the event that you do not have electric welding, you can use another popular method - “cold welding”, or tighten the weight with a metal clamp.

You will find a video instruction for adjustment in this video:

Use the services of a service station for adjusting the cardan shaft

If you don't have a lot of free time, best option to troubleshoot - use the services of a service station. Photo: ctokazan.ru

To date, almost every workshop offers balancing the cardan shaft. To be sure of the quality of work, choose a proven workshop where all work is carried out on high-quality equipment. The cost of adjusting the cardan shaft for different cars is different. Average, propeller shaft adjustment domestic car will cost you 3000-3500 rubles, and foreign cars 4000-5000 rubles. Special equipment allows balancing in a short time. And the accuracy of such balancing will be an order of magnitude higher than self-elimination imbalance.

The cardan diagnostic process is carried out on a special stand, which consists of several sensors. The cardan shaft is removed from the car, installed on the stand, after which the geometry of the shaft is analyzed. All necessary information is displayed on the monitor. After that, proceed directly to the balancing of the shaft.

Shaft balancing is performed in one of the following ways:

1. Balance plates are installed on it. In this case, the mass and place of installation of the plates is determined computer program. This allows for more accurate calculations. Fastening is carried out by welding;
2. Balancing on a lathe. In the event that the shaft geometry is significantly damaged, this method is more effective. When balancing on the machine, a certain layer of metal is removed, which leads to an increase in the load on it. This method is the most accurate and reliable for cardan shaft balancing.

Results

It is not so difficult to independently balance the cardan shaft, this process pretty light.

However, it is necessary to take into account the fact that it is not possible to ideally select the mass and place of installation of the weight with your own hands. Over time, the propeller shaft will begin to vibrate again.

To completely eliminate this problem, you need to use special equipment. Therefore, the best option in this situation is to contact the service station. With the elimination of vibration, it is impossible, using a car with a vibrating cardan shaft you can significantly reduce the life of the gearbox and other parts.

Shaft - a part of machines and mechanisms designed to transmit torque along its longitudinal axis. The most common are shafts assembled with impellers, pulleys, sprockets, etc. installed on them.

Like any other mechanical part, the shaft may be incorrectly installed in bearing supports, have inhomogeneities in the density of the material, violations in the geometry of manufacture and insufficiently accurate fit of parts rotating with it, etc. As a result of the above reasons, unbalanced masses appear in the rotating shaft, causing low-frequency vibrations of the shaft. These vibrations can be so significant that they can lead to shaft bending and complete destruction of bearing assemblies and other machine parts. That is why it is so important to balance the influence of unbalanced masses by performing a shaft balancing procedure.

Earlier, we have already considered the types of rotor unbalance and the corresponding types of balancing - static and dynamic. It was noted that the accuracy of dynamic balancing is an order of magnitude higher than the accuracy of static balancing, and that for rotors whose diameter is much larger than the length (pulleys, impellers, sprockets), only static balancing can be limited.

In the case of shaft assemblies (for example, a shaft with an impeller), in most cases it can be limited to static balancing of the impeller and dynamic balancing of the shaft assembly on the machine and / or in its own supports. In fact, a perfectly balanced shaft assembly is a shaft with separately balanced parts, then balanced as an assembly on the machine, and finally balanced in its own supports.

According to the statistics of the BALTECH company, a recognized expert in the field of balancing, proper balancing of the shafts of rotating machines increases the service life of impellers and impellers by 23%-100%, and also increases their useful power by 10%-25%.

Balancing shafts in their own bearings must be entrusted to specialists technical service"BALTECH", armed with the most modern balancing tools - mobile kits "PROTON-Balance-II" and BALTECH VP-3470 and the program of multi-plane balancing BALTECH-Balance.

The main production direction of the BALTECH company is the production of modern pre-resonance machines for horizontal, vertical and automatic type for rotors of various configurations, weights and dimensions. Let us consider in more detail the capabilities of BALTECH balancing machines using the example of a vertical balancing machine of the BALTECH VBM-7200 series.

Balancing machines of the BALTECH VBM-7200 series are designed for one-plane or two-plane balancing of shafts and parts (impellers, pulleys, disks, etc.) without shaft journals. In relation to our case of shaft balancing, cutting tools and cartridges are also balanced on these machines.

The shaft balancing procedure takes only a few minutes and includes:

• Input geometric parameters balanced shaft;
• Starting the balance shaft into rotation and taking automatically calculated data on the size and installation angle of the corrective mass.
• Installation / removal of the corrective mass.

We note in particular that high speed and measurement accuracy is achieved through the use of the BALTECH-Balance program, the standard functionality of which allows multi-plane (up to 4 planes) and multi-point (up to 16 points) balancing with vibration amplitude and phase measuring instruments of any manufacturer.

To get deep theoretical knowledge and professionally master the skills of working with balancing machines and devices "BALTECH", we recommend that you sign up for the next Course TOR-102 "Dynamic balancing" in training center company BALTECH.