In detail: do-it-yourself pneumatic wrench repair from a real master for the site my.housecope.com.
The principle of operation of a pneumohagakert
Types of faults
Disassembly of the pneumatic wrench
Repair of pneumatic impact wrench
Lubricant for pneumatic impact wrench
Conclusion
The pneumatic wrench is an indispensable tool for working with threaded connections. It is widely used in car services and numerous construction works. Perfectly tightens nuts and loosens tight connections.
The design of a pneumatic impact wrench is quite simple, but at the same time it consists of many details incomprehensible at first glance. Often, the parts of the mechanism have sufficient strength for a long service life and fail only due to wear or increased stress. Most of these problems can be detected at home without the need to contact a specialist. How to determine the location of the breakdown and fix the malfunction, we will tell you in this article.
To understand the reason for the breakdown of a tool, you should understand how it works (fortunately, the mechanism is very simple here). The pneumatic wrench consists of a fitting to which the air hose from the compressor is connected. Next is the start button, which directs the air flow into the cylinder with the rotor and blades, spinning high pressure. The motor transmits rotational movements to the stop, where the attachments for tightening the nuts are installed. If the impact wrench, then between the stop and the rotor, the impact mechanism is located.
For greater clarity and understanding of the wrench device, below are photos and videos of the tool in analysis.
Breakdowns or malfunctions of the nutrunner can be caused by wear, damage or severe contamination of its mechanism. There are many video faults, below we list the most common ones.
Video (click to play).
Low power even at maximum speed and high pressure.
Speeds or reverse are not working.
The instrument is warming up
The chuck does not rotate
Increased noise and vibration
Parts such as bearings, rotor blades, valves, springs, impact cams, gaskets, and speed control can be the cause of these problems. Depending on the level of damage to the part, it can be repaired or replaced. Let's take a look at how you can bring your impact wrench back to life.
Usually, this process does not cause any particular difficulties, due to the simplicity of the tool design and the minimum number of unscrewed elements. The first thing to do in order to get to the “guts” is to unscrew a few bolts on the back cover with a hexagon. After unscrewing, remove the cover with the gasket and the speed regulator. Having gained access to the main mechanism, we carefully remove it from the case, be sure to remember the sequence of parts. If you are afraid to mix up the parts when assembling, shoot the disassembly in a photo or video.
After taking out all the parts, the first thing we need to do is evaluate their appearance. Parts must be lubricated, free from rust and oxidation. Next, we must look at the mechanism for chips. If parts are damaged, they must be replaced. You can read the name of the pneumatic wrench parts in the picture above.
If your tool has been out of use for many years and before the malfunction it has not been used for a long time, then perhaps the cause of the breakdown lies in banal corrosion and rust formed on the mechanism for a long time of inactivity of the tool.The solution to this problem may be elementary cleaning of parts with subsequent lubrication. Even if this method does not return your tool to work in order to work in the future, it should not be dirty and without lubrication.
The tool may not function or function improperly even with a clean, lubricated mechanism. In this case, the cause of the malfunction lies clearly in the breakdown or wear of a certain part. Here you should carefully examine each component for chips, cracks or abrasions. More attention should be paid to the bearings and rotor blades, as these are the most prone to mechanical damage.
You should also carefully inspect the cylinder block and make sure that the rotor blades fit snugly against its walls. This happens when the wrench runs for a long time without oil, as a result of which the rotational force decreases significantly. If there is a clear backlash, you have 2 options for repairing the pneumatic impact wrench: installing a new block or grinding the old one. Grinding is required on the machine for a perfectly flat surface.
The service life of any power tool largely depends on the quality of lubrication of its parts. The easier the mechanism is to operate, the less wear and tear will occur. If you want the wrench to serve you faithfully for more than one year, follow the basic rules for maintaining the tool.
To add oil to the wrench mechanism, you do not need to disassemble it. It is enough to add about 8-10 drops of grease to the tool nozzle where the air hose is installed, then start and let it idle for 30 seconds so that the oil is quickly distributed over the parts. This procedure should be repeated every 3-4 hours during continuous operation, as well as before putting the tool away for storage.
If you use the tool all the time, adding oil every 4 hours can become a chore. To eliminate unnecessary distractions from your workflow, install a wrench oiler (lubricator) that will deliver oil gradually as you work. This method is more convenient and provides constant lubrication of parts, just remember to add oil to the lubricator itself.
Many articles have been written about pneumatic tools, their advantages, device, and operating features. As a rule, the information provided in them is limited to general information and recommendations. In this article, we will try to tell you in detail about the features of the preparation of an air line and the main mistakes made by users.
So, you have acquired a pneumatic tool. What must be done in order for the instrument to serve for a long time and function according to the characteristics declared by the manufacturer, and what should not be done in any case?
It is clear that the pneumatic power tool is powered by compressed air. But what are the basic requirements for this air?
Air quantity should be sufficient for the full operation of the tool.
Carefully read the instructions for the product you purchased. The manufacturer must indicate such an important parameter as the average cyclical air consumption. As a rule, the pneumatic motor is rather "gluttonous". The compressor you are using must have sufficient capacity, and its receiver must be large enough so that the instrument does not “blow out” it in a few tens of seconds. For example, an attempt to use a wrench with an average cyclic flow rate of 120 liters per minute in conjunction with a household compressor with a receiver volume of 24 liters will not lead to anything good. And a compressor with a receiver capacity of 50 liters is unlikely to allow full use of the wrench. It will last for a few seconds of normal operation.After that, the pressure in the system will drop, and the wrench will not develop the required force. Also, every minute switching on of the compressor operating at the limit of its capabilities will lead to its rate of wear and failure.
Next, you should pay attention to pipes, hoses, adapters and other elements of the system through which air will flow to the tool. It is important that the duty cycle of the channel is sufficient along the entire length of the pneumatic line. The constrictions will limit the amount of air supplied and the tool will operate at half strength. It is desirable that the duty cycle of the channel is not less than the diameter of the inlet of the choke through which air enters the tool.
System pressure... Most pneumatic tool manufacturers recommend setting the system pressure to 6.2 kg / cm². If the pressure is lower, the tool will not deliver the required power. Too high pressure will lead to premature wear of key components and tool failure.
How to set the pressure correctly using the regulator? Connect the tool to the pneumatic line. Using the regulator and pressure gauge, set the system pressure to 6.2 kg / cm². Press the power button of the tool, the tool should be in idle mode. With the tool switched on, set the system pressure to 6.2 kg / cm².
Air quality... The air must be free of foreign matter that could damage the instrument. When the air is compressed, condensation forms inside the receiver. When the compressor is severely worn, oil also enters the receiver. Mixing with the moisture of the condensate, the oil forms an emulsion, which enters the air motor through the pneumatic line and causes corrosion of its parts.
In practice, we had to repeatedly deal with nutrunners arriving at the service center, the interior of which was filled with water and rust. The impression was that the wrench had been drowned in a swamp for at least a year. It is surprising how in such conditions he was able to work for so long.
The filter drier allows you to solve the problem of air purification. A foamed bronze mesh is installed inside the filter. Passing through it, the air gives off moisture and other impurities, they settle in the sump. The filter housing is usually made of transparent material, which allows you to monitor the amount of accumulated contamination. A valve at the bottom of the sump is designed to remove them. It happens that in the presence of strong contamination, the bronze filter element becomes clogged and cannot provide the required air flow rate. A typical symptom will be a drop in the power of the instrument. After starting, the engine starts to work at the proper speed due to the air accumulated in the hose, but after a couple of seconds it slows down, because the filter does not allow air to pass through in the required volume. Remove the filter housing and wash the filter element in solvent, blow it with air. If this does not help, the filter element will have to be replaced. They are sure to be in the assortment of companies supplying pneumatic tools and pneumatic preparation system elements.
Air motor lubrication.
Lubrication plays a decisive role when it comes to the operation and life of the pneumatic power tool. Oil not only reduces friction between moving parts of the engine. Its main role is to remove wear products. When the rotor blades rub against the cylinder walls, the finest dust is formed. It fills in tiny gaps between rotor slots and blades. The blades stop moving freely and the motor loses power. I'll reveal a little secret. When a tool that does not develop power arrives at our service department, an experienced mechanic fills the cavity of the motor with penetrating grease, injecting it through the air supply connection, and leaves the tool for several hours.Lubrication flushes contaminants out of the engine clearances. After that, you need to thoroughly blow out the tool with compressed air, and it is again ready for use. In almost half of the cases, this technique works.
How to properly lubricate the tool? The lubricant is supplied to the tool motor along with compressed air. For this, a device called a lubricator is installed in the pneumatic system. Oil is poured into the lubricator through the hole in the upper part. The transparent body, marked with minimum and maximum level marks, allows visual inspection of the presence of oil in the system. When supplied, the air is enriched with a suspension of oil, which flows through a hose to the tool. In practice, it is convenient to use an air preparation unit called a modular group. It includes a filter drier, lubricator, pressure gauge, pressure regulator and is installed directly in front of the hose to which the pneumatic tool is connected.
It should be borne in mind that with a hose length of more than 10 m, it will be difficult for oil to flow to the tool. It will require the use of additional linear lubricators installed directly on the inlet connection of the tool.
Use only special oil for pneumatic tools with the appropriate viscosity. As a rule, companies offering pneumatic tools have it in their assortment.
In practice, one has to deal with situations when consumers use engine, transmission oil. It happens that fluids that are not at all suitable are used. Our service center received a wrench, the motor of which was filled with a substance resembling furniture varnish in smell and consistency. High viscosity oil "sticks" the engine blades and does not allow it to develop power. The harm from such a lubricant will be more than good.
With intensive use, it will not be superfluous to additionally lubricate the tool. It is not for nothing that there is an inscription OIL DAILY on the tool handle next to the air supply connection.
Before starting work, inject a few drops of oil (but not too much) through the air inlet. Your instrument will be grateful to you and will serve you for many years!
Somehow I had to repair a drill, a wrench and a grinder still Soviet. - Check the "tap"; - check the bearings; - check the rotor.
In all cases, the rotor blades were either broken or worn out on the “instruments”. He gave the drill to the boring-grinding of the "cylinder". The body covers (covering the ends of the "cylinder") had wear - they were ground by hand on a good, even fine-grained wheel. I made the plates: I picked up the textolite (with fabric) by thickness, made the blanks, boiled it for about 2 hours in oil (mineral, not butter) over low heat (regulated power supply, outside!). Finally, I adjusted the plates "in place" - so that it would not wedge, but there were also minimal gaps at the ends. Changed bearings. It was already possible to work with 3-5 atmospheres. at 6 atmospheres (industrial pneumatic line at the enterprise), a small drill (rotor about 20 mm in diameter and 30 mm long) was simply not able to be held by hand.
PNEUMATIC WRENCH, Nordberg IT 250, GREAT TO +, WRENCH REPAIR KIT PNEUMATIC WRENCH Nordberg IT 250 Square size 1/2″ Maximum effort 740 Nm Speed 7500 rpm Weight 2.8KG Air consumption 133 l / min Pressure 6.2 bar ═══════════════════════════════════
Any craftsman knows that the most laborious process when assembling structures or repairing mechanisms is loosening and tightening threaded connections.But if pneumatic wrenches are used for these purposes, then such work turns into an ordinary formality. This convenient tool has many advantages, but you should learn more about the nuances of its operation.
In the figure below, you can see in detail the device of the pneumatic wrench. The unit consists of the following elements, placed in a sturdy metal case.
High performance air motor.
Impact mechanism.
Alloy steel chuck (stop).
Torque regulator, and reverse.
Start button.
Fitting for connecting a hose from the compressor.
Air valve.
Due to the absence of a motor, this unit is much lighter than its electric counterpart. And the torque of the wrench has high performance - from 300 to 2200 Nm (Newtons per meter).
Inside the unit can be distinguished 2 main power blocks, each of which is designed to work in different modes. The first unit is an air motor that transmits rotary motion to the tool head. The second block is the knot that generates shock loads. The pneumatic drive rotates due to the passage of compressed air through it, supplied by means of a high-pressure hose from the compressor.
In the body of the device there are 2 channels... For each of them, air is directed in different directions relative to the turbine. In the first case, the air pushes the turbine in the clockwise direction, that is, for twisting, and in the second, against the clockwise arrow, for unscrewing the fasteners. Air flows are distributed by a special switch.
Principle of operation pneumatic wrench is as follows.
After pressing the start button, the valve opens, and the air flow from the hose connected to the body of the apparatus begins to move through the turbine, rotating it.
From the turbine, the rotary motion is transmitted to the impact mechanism, which in its principle of operation resembles a clutch. The mechanism includes 2 cams of complex configuration. The impact force is generated by the cams when there is not enough torque when the fastener is released.
Further, the rotational movement is transmitted to the stop (chuck), on which the nozzle is put on for a certain size of the nut. As a result, the fasteners are twisted or unscrewed. Some air wrenches do not use the impact mechanism when tightening, the process takes place in a shockless mode.
If the nut is stuck, then to unscrew it, it will take more effort, and at this moment the rotation of the stop stops.
The hammers begin to tilt back while turning.
At the next stage, the cams pass the engagement with the stop and, continuing to move, gain momentum.
Continuing to turn, the cams again engage with the stop and strike it (in the direction of travel).
Shock impulses continue until the fastener “breaks” from its place.
Thus, with the help of a pneumatic impact tool, the process of loosening tight bolts and nuts is easy and quick.
