In detail: do-it-yourself electric drill interskol repair from a real master for the site my.housecope.com.
An electric drill in a home workshop takes a special place. Therefore, tool breakage is a big enough nuisance. Despite the complexity of the design, it is quite possible to make an independent repair.
2.button with switch-on unit - can be equipped with
4.Gearbox housing - carries out load-bearing functions for rotating
5. gears and reducer mechanism;
6. bearings of the shaft of the cartridge and the armature of the engine;
8. brush assembly of the electric motor;
9. chuck with drill or cutter holding mechanism.
The drill never breaks as a whole: one of the elements fails. Having understood the design and interconnection of the power tool assemblies, it will be easier to localize the malfunction.
Drill repair is carried out according to the principle "from simple to complex". You should not immediately disassemble the tool to the screw, and assess the condition of all nodes at the same time.
The drill does not turn on. We start with the power cord (at least before that, you should check the voltage in the outlet and extension cord). Having disassembled the case, we find the cable contacts, and "ring" them with a multimeter.
Important! Do not check the power cable with voltage applied! If the current-carrying conductors break, you can get an electric shock, or organize a short circuit.
We connect to the socket of the mains plug and the opposite terminal of the cord. Then we bend the cable several times along its entire length. Lost contact or its complete absence indicates the presence of an open circuit inside the insulation. If the fracture of the current-carrying conductor is close to the edge, the cable is cut and reconnected. It will just be a little shorter. If the gap is in the middle of the length, it is better to replace the wire. The splicing will be unsafe.
Video (click to play).
The cord is working properly - we check the switch. We connect the multimeter to the terminals, and press the key. A large current flows through the contacts, sparking occurs (especially when dust enters the case). Contacts can corny oxidized. Carefully disassemble the switch body and clean the contact groups with fine sandpaper.
In case of breakage of metal parts, it is better to purchase a new unit.
If there is an additional contact group in the circuit between the switch and the electric motor (for example, a reverse switch or a speed regulator), we diagnose this node as well.
Next, we check the connecting wires from the switch to the motor brushes. If they are in order, we diagnose the brush assembly.
The springs should confidently press the brushes against the anchor lamellas; we check the carbon elements themselves for wear. If necessary, we change: spare parts are included in the delivery set, or purchased in specialized stores. The armature contact strips can be oxidized or clogged. They can be gently cleaned with fine sandpaper.
A more complex breakdown is failure of the armature or stator windings. Using a multimeter, a short circuit is checked between the body of the unit and the contacts of the windings. Then the resistance is measured. The value should be the same on each winding, the variation in readings should be no more than 5%. Defective windings must be rewound.
This can be done on your own, or in a repair shop (in any case, it will be cheaper than buying a new engine).
Such breakdowns manifest themselves quite clearly. Extraneous noise, grinding, shaft jamming, etc.
The motor rotates slowly and the windings get very hot.Or, during normal rotation, a characteristic hum (grinding) is heard. Most likely - the rotor bearings are worn out or clogged. Having disassembled the drill body, we carefully take out the rotor. It is removed together with the bearings. By twisting the outer clip, you will immediately determine the malfunction. If the bearings rotate tightly, they must be flushed with a penetrating liquid (WD-40 or regular kerosene)
Important! Make sure that no liquids get into the armature winding! Otherwise, the insulating varnish may dissolve, and an inter-turn circuit will occur.
Then grease is placed between the clips for high-revving units. Lithol or graphite grease for automotive bearings will do.
If there is a backlash between the bearing races, the units must be replaced.
Dismantling is carried out with a special puller or with an open-end wrench.
If there are no balls, be sure to find them in the case. Dropped objects can get caught between engine or gearbox parts and damage the entire unit.
The bearings of the chuck shaft are diagnosed and repaired in the same way. Only dismantling them without a puller will not work.
If the mounting place of the outer bearing race (bed) is worn out (this happens when the bearing is jammed), you will need to make liners of thin sheet metal. Otherwise, beating will occur when the shaft rotates.
The engine rotates in normal mode, noise and grinding noise are heard from the gearbox housing. The shaft turns unevenly. Worn or destroyed gears of the reducer.
We disassemble the case and examine the gears.
It is advisable to wash the assembly of old grease and rotate the shaft 360 °, controlling the engagement of the gears. If a backlash or excessive wear of the teeth is detected, the mechanical part will have to be changed.
Perhaps a large amount of dust has simply accumulated in the gearbox housing. Together with the lubricant, an abrasive paste is formed. In this case, after flushing the assembly, simply add new grease.
Tip: The grease should be changed periodically without waiting for breakage.
Especially if you often drill stone walls.
The cartridge is broken. For cam devices (turnkey) this is a great rarity, the design is reliable and simple. The unit is exposed to dust, so the internal mechanism can easily jam. Most often, the gripper guides are clogged with small abrasive particles.
If the chuck does not twist well, it is enough to blow it out with compressed air and treat it with a penetrating lubricant.
Attention: The jaw chucks do not lubricate the inside!
It is quite difficult to disassemble a part without a special tool. If some component is mechanically broken inside, you still have to change the entire assembly.
But keyless chucks, on the contrary, are easily disassembled and repaired.
They are not as reliable and do not carry the load well. To disassemble such a cartridge, it is enough to remove a pair of lock washers. You will easily find a broken or worn part that can be easily replaced.
There are two types of fastening: Morse taper, and threaded. In the first case, you need to inflict several blows with a small hammer on the back of the cartridge. After which it can be easily removed.
To unscrew the threaded fastener, the shaft is held with a wrench (there are special flats on the shaft).
There are no faults that cannot be corrected by hand. If a separate unit cannot be restored, only it changes, there is no need to buy a new drill.
To prevent breakdowns, you should adhere to simple rules:
After dusty work, blow out the ventilation holes and the interior of the cartridge. Keep the instrument clean.
Do not overheat the engine - take breaks for prolonged use.
Refill the grease on the rotating parts periodically.
An electric drill is one of the most common household tools. And it's very bad when it suddenly stops working.In such cases, I really want to repair the drill with my own hands.
Electric drill device diagram.
The design of a drill or hammer drill is quite simple. Different tool models mainly differ only in the difference in the arrangement of parts and the quality of their manufacture. The versatility of the operating principle and structures used allows you to make independent repair of the drill in most cases of malfunctions.
Any electric drill consists of a body, which houses the electrical and mechanical parts, and a chuck, in which the drill is mounted, on the main shaft of the drill. The electrical part usually contains:
electric motor;
contact brushes fixed in the brush holder;
start button (switch);
engine speed regulator;
reverse device;
starting capacitor;
power cord (cable).
Diagram of the percussion mechanism of the drill.
In turn, a two-phase AC motor consists of a stator and a rotor (armature) with a collector.
The mechanical part includes a gearbox and a bearing system. The gearbox transfers the rotation of the electric motor to the drill shaft, reducing the rotation speed. A more complex mechanical part in a hammer drill (hammer drill). The hammer drill's reducer provides the percussion-translational and rotational movement of the drill (drill). Its design, in addition to the gear, includes pistons (shock and flying), ram and firing pin.
A malfunction of the electrical part manifests itself in the form of a lack of rotation of the engine, i.e. when there is no indication that the engine is running (hum, vibration, etc.). If the impact drill does not turn on, and the cartridge is easily turned by hand, then we can safely talk about a malfunction of the electrical part. The same can be said if there is no speed control or reverse rotation. An expected malfunction in the electrical part is indicated by sparking during the operation of the drill. Temporary interruptions in the operation of the drill, extraneous noise can also indicate an electrical circuit.
Most often, a malfunction in the electrical part is due to wear of the contact brushes. If they are cut by 40%, then sparking and malfunctions can be observed. With more wear on the brushes, the electric motor simply does not turn on. The procedure for determining the culprit of a malfunction in the electrical part is recommended as follows (as available). First, the tester determines the integrity of the cord (cable). Then the operation of the start button (switch) and the integrity of the starting capacitor are checked. Then the contact buttons are removed and checked. Finally, the integrity of the motor windings is determined.
A clear sign of a mechanical problem is a jammed drill shaft. If the cartridge cannot be rotated by hand, and at the same time the hum of the electric motor is heard when turned on, then the reason lies in the breakdown of the gearbox or bearing. The most common cause of mechanical failure is the failure of thrust bearings. A breakdown of the gearbox can also appear in the case when the chuck is turned by hand and the electric motor is running, and the rotation is not transmitted to the main shaft. A malfunction in the mechanical part can cause periodic malfunctions (temporary stoppages) of the drill, hum, grinding and insufficient shaft rotation speed. In rock drills, a malfunction in the mechanical part can remove the impact movement of the drill.
Finally, a malfunction can manifest itself in the drill chuck. So, it can be difficult to remove the drill when the cams do not open due to breakage in the engagement inside the chuck. Sometimes the malfunction manifests itself in the form of scrolling the chuck relative to the drill shaft. In this case, a malfunction occurs in the area where the chuck is attached to the shaft.
One of the most common causes of malfunction is wear or burning of contact brushes.The first signs of brush wear appear in the form of sparking in the contact area of the brushes with the electric motor armature and minor malfunctions of the drill when the load is increased.
The location of the contact brushes inside the drill.
Many drill models have simplified access to the brushes, and changing them is not difficult, and some drills require disassembling the body and removing the brush holder. The brushes must be replaced with new ones equal in size to the failed brushes.
They should be firmly attached to the brush holder. The electrical contact of the lead wire must be tightened well. The contact of the brush with the armature collector must be reliable. It is necessary to check the action of the spring.
Failure of an electric motor is the second largest cause of a drill malfunction. This is due to damage to the stator winding or armature. Such damage occurs due to a factory defect in the windings or improper operation of the drill (long-term operation without interruptions, the load in excess of the permissible load when the drill is jammed, etc.). As a rule, electrical breakdown of the winding is easily identified visually or by the characteristic burning smell. If there are no visible manifestations, then the motor windings should be checked with a tester, ohmmeter and megohmmeter for the value of resistance. There may be three types of wire damage - short circuit between turns, breakdown of a turn to the body, or wire breakage. Repair of the stator or armature is not carried out independently.
Drill motor connection diagram.
To replace the elements of the electric motor, the drill body is disassembled, the contact brushes and lead wires are disconnected, and the electric motor is removed together with the support bearings.
If necessary, retract the drive gear. The faulty element of the electric motor is disconnected and replaced with a new one or the old one is installed after repair (rewinding) by professionals.
The switch (start button) and the rotational speed regulator in the drill are usually combined. The speed is regulated by pressing the button with different efforts. First, you should check the presence of voltage at the input and output terminals of the button. If there is no signal, then carefully remove the button housing and inspect all contacts. As a rule, burning or sticking of contacts is determined visually. All contacts must be thoroughly wiped with alcohol and cleaned with sanding paper. After that, the presence of voltage should be checked again. If there is no signal, the button should be replaced with a new one. The cause may be a violation of electrical contact with the wire. In this case, the wire must be soldered.
Drill button connection diagram with reverse.
The reverse rotation mechanism is based on a system of make and break contacts. Its prevention is carried out in the same way as the start button. In addition, you should check all the wires of the mechanism going to the brushes and the stator of the electric motor.
The reason for the impossibility of starting the electric motor may be the failure of the starting capacitor. Usually, a non-working condition of a capacitor is noticeable by a color change. But it is more reliable to measure its capacity and compare it with the nominal value.
Checking the electrical part begins with determining the integrity of the power cord (cable) using a tester or ohmmeter.
The resistance between the contacts of the plug is measured (determination of the short circuit of the wires) and the resistance of each core.
A jammed chuck or a grinding noise indicates a failure of the gearbox or bearings. First of all, you should disassemble the drill body and inspect the condition of the gears in the gearbox. The wear of the mounting splines or the destroyed teeth of the gears indicate the failure of the part. This gear must be replaced. The gears are inspected along the entire circumference, smoothly turning the shafts by hand.
The bearings are checked by turning the shaft in them. If the shaft is sluggish, start by lubricating the bearings.If this does not help, then they are removed from the axle using a special puller. The bearing cage is scrolled by hands. If movement is difficult or extraneous sounds are heard, then the bearing should be replaced.
During prolonged use of the drill, the cartridge may fail. Sometimes this manifests itself in the impossibility of removing the drill - the adjusting sleeve does not rotate or, on the contrary, it easily scrolls, and the jaws do not move apart. This indicates wear of the gear joint in the chuck due to metal shavings and dust. In this case, the repair is reduced to replacing the cartridge. The chuck is usually fastened to the shaft with a left-hand thread and is fixed with a screw. The cartridge can be removed by unscrewing the screw and turning the cartridge in the opposite direction with force. In some models of drills, the chuck is installed using a tapered surface in an interference fit. In this case, it must be knocked out with light blows to the end from the side of the drill body.
To repair a drill with your own hands, you need the following tools and devices:
