Quite often, problems with buttons are associated with poor contact at the terminals. You can simply perform the procedure for cleaning the contacts with sandpaper and the problem will be solved. The main thing is to do everything carefully in the process of disassembling and assembling the device, without losing parts.
A broken gearbox is one of the mechanical problems with a screwdriver. Some of the most common problems with the reduction unit include:
To correct these defects, it will be necessary to physically replace the defective parts, therefore, this type of repair should be entrusted to qualified specialists who are able to correctly and accurately diagnose the breakdown and eliminate it.
VIDEO A screwdriver is a tool often used in the professional field during repair and construction work, as well as in everyday life. Like any electromechanical device, screwdrivers are prone to malfunction.This device is not a complex device, and in the event of a malfunction, the repair of the basic malfunctions of the screwdriver can be done by hand.
Below is a figure showing the internal structure of the battery device.
In screwdrivers, both collector motors and brushless motors can be installed (do not have electric brushes).
If your screwdriver breaks down, then the malfunctions of this unit may be as follows.
All faults, except for the electrical plug, can be eliminated only after disassembling the device.
To disassemble the device, follow these steps:
disconnect the battery pack from the body of the device;
unscrew all the fasteners holding the 2 halves of the device together;
remove the upper part of the case;
remove all contents from the body of the device;
carefully disconnect the start button from the case without damaging the wires connecting it to the engine;
remove the speed switch;
disconnect the motor, gearbox, coupling and cartridge by unscrewing 4 screws;
To unscrew the cartridge, you need unscrew the screw , which can be seen inside the mechanism when the cams are open. Unscrew the screw clockwise as it has a left-hand thread. After that, the chuck must be unscrewed from the gearbox shaft by turning it to the left (right-hand thread).
If you have a battery pack, the first step is to check the batteries in the battery pack by disassembling it. There are collapsible and non-collapsible blocks. In the second case, you will need to carefully insert a screwdriver into the place where the block walls are glued and, slowly, separate them.
Further, it is necessary measure voltage on all "banks". The voltage rating is indicated on the case of each battery. The voltage should be slightly lower than indicated, but the same on serviceable batteries. Defective batteries will differ significantly from the rest in terms of voltage output - they will need to be replaced. New batteries can be purchased online.
It is important to solder them correctly, that is, in series: the plus of one battery is connected to the minus of the other, and the plus of the second with the minus of the next, etc.
If you are the owner network screwdriver , then the verification algorithm is somewhat different. First, you need to unscrew the body of the device and remove one half of it. Take the tester and ring the power cord for an open. In the case of a working cord, you need to check the start button. With the button pressed, check if there is a circuit on its output contacts. If the button is faulty, it will need to be replaced or repaired. How to do this will be discussed later. With a working button, the problem may lie in the electric brushes or the motor.
Below is the electrical diagram of the cordless screwdriver.
It can be seen from the diagram that 2 wires from the battery are suitable for the button, and 2 wires go out of it to the engine. Also, 3 wires are connected to the button from the transistor, which is responsible for adjusting the speed. To understand the structure of the screwdriver button, it must be disassembled. All wires going to this part do not need to be unsoldered. They will not interfere with disassembly.
Take off push mechanism (red) from its seat. Do this with gentle rotational movements, while simultaneously pulling the part in the direction opposite to the button, being careful not to break the jokes.
Next, remove button cover ... In the places indicated by the arrows in the figure, using a knife and a screwdriver, it is necessary to pry and push out the latches, and then remove the cover.
Removing the cover, you will see reverse compartment ... But the button mechanism will still be unavailable. Using a soldering iron, separate the 2 elements (indicated by an arrow in the next figure).
Carefully pull out the element numbered 1, then remove the cover that covers the compartment with the device turning on mechanism.
Holding the return spring, remove the mechanism from the case.
In the faulty button, you will see the erased pads.
Contact pads wear out quickly due to the poor quality of the metal. Fine metal dust from worn out contacts accumulates between them and closes the pads. As a result of this, a spontaneous start of the apparatus occurs.
Remove metal dust using cotton wool dipped in alcohol. If this fails, you can scrape it off with a knife. After these actions, the spontaneous start of the device will stop.
If the speed regulator does not work, then the transistor has burned out, which must be replaced.
To check the condition of the brushes, you must disassemble engine , bending back the "antennae" located at the end of the body.
Then, with light blows of a hammer on the motor shaft, knock the rotor out of the housing.
In this case, first, the cover is removed, in which the electric brushes are located.
The next photo shows that the collector has black color ... This means that it will get dirty with dust from the brushes. As a result of contamination of the collector, as well as the grooves between its plates, the engine power decreases and the brushes spark. It is necessary to wipe the collector with cotton wool soaked in alcohol and clean the grooves with a needle.
The following photo shows what a clean manifold looks like.
If the brushes are worn out, they will need to be replaced. Some models of screwdrivers are difficult to find on sale original brushes ... But you can find brushes that are suitable in size, then trim them on a grinder and connect (solder) to the brush holders.
Sometimes, in order to replace the brushes, you will need to saw a groove in them. It depends on how you attach them.
To better understand how the brushes are replaced, you can use the following video.
The engine brake is a device that stops the rotation of the armature at the moment the start button is released. In screwdrivers, this function is implemented by closing the plus and minus of the motor when the button is released. As a result, a large self-induction occurs, and there is spindle lock (with a lot of sparking from under the brushes). If the engine braking does not work, then it will be necessary to replace the regulating transistor or start button.
Mechanical failures of the screwdriver include malfunctions of the ratchet, gearbox and chuck of the apparatus.
If the ratchet does not work on the screwdriver, then you will need to disconnect it from the gearbox for troubleshooting. Sometimes special rods are installed in the coupling, which regulate the force, and in some devices, instead of rods, 2 balls are installed in each hole. They are pressed by a spring, which, when the adjusting ring is twisted, presses on the balls.
In most cases, repairing a screwdriver ratchet consists in cleaning its components from dirt and applying new grease.
If unusual noises are heard in the gearbox, or the spindle rotates in jerks, with slipping, then the failure of the gears of the mechanism, the worn-out teeth on its body, may be the cause.
Gears most often break if they are made of plastic (used in cheap machines). If this happens, then they must be replaced.
In the next photo you can see the device of the gearbox.
The reason that the spindle does not rotate when the engine is running may be the wear of the plastic teeth inside the gear housing.
To restore the mechanism to work, it is necessary to disassemble the gearbox (it is better to photograph the disassembly process) and screw it in place of the worn teeth small bolt , ground down to the required size. The place where you will install the bolt must be screwed. It should be located strictly opposite the plastic tooth located on the inside of the case.
Make such markings on the back of the case, opposite the first one.
Next, drill holes in the marked places.
Screw the bolts of the required length into these holes, having previously grinded off so that they are flush with the other plastic teeth. After adjusting the bolts, you can assemble the gearbox with the required amount of lubricant on the gears. This completes the repair of the screwdriver gearbox.
To start repairing this unit, you must first remove the chuck from the screwdriver ... For this, a complete disassembly of the screwdriver is not required. How to unscrew the keyless chuck is described above.
Frequent chuck malfunctions include incomplete output of one of the cams, as shown in the following photo.
The cause of the malfunction may be worn out thread on the nut clamping the cams, or worn teeth on the cams themselves. To verify this, you will need to disassemble the cartridge.
Disassembly and repair of the screwdriver chuck is done as follows.
It is necessary to hit with a hammer on the part protruding in its center. In order not to deform this part, you can lay a small piece of wood.
The top section will not be enough and further chuck disassembly will be required. To do this, lightly clamp the bolt into the cams and hit it with a hammer.
When the inside of the cartridge falls out, its analysis is complete. You will see nut consisting of 2 halves ... Most often, malfunctions in the chuck arise from this part. The thread on it wears out and the cams slip when tightened. Therefore, there is an incorrect centering of the latter.
Also, the thread can be worn on the cams, which, like the nut, must be replaced. But if you do not find the necessary parts to change them, then you will need complete replacement of the cartridge ... When assembling the cartridge, the cams must be installed at the same level, in a compressed state, after which a nut consisting of 2 halves is put on, and after that the whole structure is placed in the body. When the malfunction is eliminated, you can assemble the screwdriver.
In practice, finding spare parts for a cartridge is troublesome. It is easier to buy a new chuck, since its price is not so high, within 300 rubles.
VIDEO
The device of screwdrivers is familiar to many professional builders who can disassemble it and correctly repair it. In any case, this can only be done by understanding all the details of the screwdriver mechanism, including the gearbox. This element should be responsible for the process of transferring rotation from the engine to the chuck device, which drives the impact mechanism of the tool.
Network screwdriver device.
The design of the rotary hammer on the gearbox has its own characteristics. The location of the gearbox can be horizontal or vertical. The heavy weight and large dimensions of rock drills with a vertical gearbox make them more powerful and reliable, with a high impact force. These types of tools are used mainly by professional builders, and not by craftsmen working at home. In general, the gearbox determines in which mode the tool operates. The work of the punch is reduced to two or three functions.
Figure 1. Typical screwdriver reducer device.
The perforator is a convenient and easy-to-use device, the beginning of its use is associated with space flights, where it was used by astronauts. New models of screwdrivers are being produced, so the demand for them does not fall. This device is suitable for various household items and repairs.
The action of the screwdriver gearbox resembles the operation of the drill gearbox, the distinguishing characteristic is the complete set of the part and the gear ratio. The gearbox of any of these tools requires regular inspection.The uninterrupted operation of these devices is associated with a periodic check of the working condition of the gears and the lubrication of the gearboxes, which sometimes requires replacement.
The gearbox mechanism includes spur, bevel and worm gears. The gear ratio of the gearbox is constant. The number of revolutions of the chuck and the frequency of blows are regulated by means of an electronic regulator. There are models of devices with two-speed gearboxes. During operation, the device must not be overloaded, that is, it must not be operated for more than 15 minutes. The perforator must cool down every quarter of an hour, since the device cannot work continuously.
Diagram of the internal structure of the screwdriver.
There are two-stage and three-stage gearboxes for screwdrivers, which is determined by the number of elements in the mechanism. The carrier and the satellites are interconnected with the gearbox shaft, on which the cartridge of the device is attached. These parts are included in a ring gear, which must be firmly fixed in the gear housing.
To fix this gear, projections are used, abutting against special protruding balls, to which the ring is attached. Due to the ring, the balls are springy, which is also influenced by the presence of a spring related to the load limiting system. The degree of spring tension depends on the position in which the mechanism regulator is located.
Depending on the material used to make the satellites, gearboxes are divided into metal and plastic. It all depends on which tool is used: professional or amateur. If the modification of the hammer drill is a household one, then the provision of a torque reaching up to 10-15 Newton meters (Nm) is due to plastic gears.
The device is a cordless screwdriver.
In addition to the ring gear, the gearbox includes a sun gear and a central gear, which are pressed onto the armature shaft; ring gear cylinder having an inner circumference along which the satellites can move due to the teeth on the circumference. The satellites also have teeth. Rotating around their own axes and the axis of the central wheel, they can constantly engage while working with the tool. The satellites are seated on each of the pins associated with the carrier.
The optimal speed due to the metal satellites is ensured when the gearbox is operating with a maximum torque that ranges from 25 to 150 Nm. Depending on the torque, screws of one length or another are used, suitable for different materials, i.e. wood, steel or concrete. The presence of a regulator in the device allows you to select the most suitable torque for the purpose of performing work using a hammer drill.
Possibilities of household screwdrivers.
Often, the gearbox is a fairly powerful steel element, but plastic models are cheaper. The motor shaft of the device is upset by a gear, and the reducer has gears in the amount of three pieces. This drive is called planetary. The gearbox itself is quite simple to remove from the case, you can assemble it without much difficulty.
To prevent the gears from falling out of the gearbox, they are inserted at an angle. This prevents the gears from dropping out when tilted. The gearbox is removed from the ratchet with the housing. The chuck is fixed by a screw, and the chuck thread is provided for unscrewing it, which is right.
The impact mechanism of the hammer drill is based on the transmission of the rotary motion emanating from the engine to the chuck. A professional worker will be able to carry out high-quality repairs, who will not harm the device and his own health, who will be safe thanks to his work experience.
Table of characteristics of screwdrivers.
To properly disassemble a screwdriver of any model, detailed knowledge of their design is required.The main parts of a planetary gearbox are the following:
These parts and assemblies can be made of plastic or metal. In the process of disassembling the gearbox, the cartridge is snapped off from it due to the spring that controls the compression ratio. A cone is installed behind the chuck, which is rotatable. The spring coming from the chuck produces pressure on the balls in the body. From the balls, the pressure passes to the reducer. When disassembling, they spill out, therefore, disassembly should be carried out on a cleaned surface so that not a single part is lost.
The ring gear has rotating satellites inside that drive the sun gear of the engine. The rock drill carrier has a lower speed than its motor. The first carrier transmits the torque to the second by rotating the sun gear. This allows you to reduce the speed of the second carrier connected to the chuck shaft. The operation of the three-stage gearbox is similar, but with the addition of an additional planetary gear set.
Electrical components of the screwdriver.
In any case, the sequence for disassembling the screwdriver gearbox includes the following steps:
Removing the cartridge.
Unscrewing the case.
Disconnecting the gearbox from the engine.
Removing the plate.
Removal of all parts from the body.
Unscrew all bolts that connect both halves of the gearbox.
Correction of the spring diameter using pliers to the smaller side in order to improve the gear engagement.
Disassembly of the coupling by removing the retaining ring, washers, bulk bearing.
Removing the shaft.
The reducer device consists of three gears that receive rotation from the central gear of the motor shaft, as shown in Fig. 1. The outer sleeve is set in rotation due to the existing rifled teeth, meshed with a gear, which belong to the first and second reduction stages.
The rock drill is equipped with a critical load mechanism that has a disc with a number of holes. They are drilled to accommodate spring-loaded fingers having high frequency current hardened ends. This design has a hardened liner edge that belongs to the gearbox.
The sleeve has recesses made specifically for the fingers of the first disc. The finger mechanism is adjusted by the usual tightening and unscrewing of the nut thread, which is associated with the strengthening or compression of the springs of this mechanism. Excessive force is associated with pulling through the ratchet of the fingers, so the process of rotation of the chuck in the gear mechanism stops.
VIDEO
When buying a screwdriver, it should be borne in mind that the manufacturers of this type of tool do not manufacture repair kits for the device.
Almost all repair of the gearbox after disassembling the tool will be reduced to cleaning and lubricating it.
A common cause of screwdriver breakage is debris getting into the plain bearing.
If parts are found that are worn out, then the entire assembly should be replaced. The high-quality operation of the screwdriver is not associated with the presence of excessive grease in the gearbox.
A screwdriver after prolonged use can have not only electrical faults, but also mechanical ones. These types of breakdowns can be associated with the appearance of abnormal sounds, indicating that the bushing or bearing is worn out. Therefore, after the inspection, damaged parts are identified, which are then replaced with new elements.
If, during the operation of the screwdriver, sticking occurs, which will be accompanied by a grinding sound, then this malfunction can be attributed to the poor-quality operation of the gearbox.
The main causes of mechanical failure:
Damage to the bearing or reducer sleeve.
Worn gear teeth or clutches.
Deformation of the gearbox shaft.
Damage to the pin with which the satellite was fixed.
Cartridge beating.
If chuck beating is detected, a bent gear shaft may be detected. At the same time, this may be due to the high wear of the bearings. Various models of screwdrivers include not only bearings, but also copper bushings as part of their device.
VIDEO The operation of the reducer couplings is associated with constant wear of the couplings with teeth. The operation of the tool as a whole, associated with certain modes, may be accompanied by a weakening of the actions associated with the high-quality operation of the couplings, their slippage. These washer-like elements will be worn out.
Recovering these items is not possible because they cannot be recovered once their condition has been determined. Therefore, new gearbox parts should be purchased and replaced with old ones.
A wonderful invention, a cordless or cordless screwdriver, like all power tools that work a lot and intensively, tends to break at the most inopportune moment. It takes a long time to repair through the service department, and sometimes not very high quality. In addition, the breakdown is not always so serious that it takes several precious days to fix it. It is easier and faster to repair a screwdriver with your own hands, especially if you have some experience with such a tool.
Most often, in a screwdriver, those parts and assemblies that experience the highest load during operation break down. If you look at the internal structure of the screwdrivers, shown in the photo, it becomes clear that the tool consists of four main components:
Cartridge with a reducer;
Electric motor;
Start or start button;
Rechargeable battery.
Of the listed parts of the screwdriver, any component, with the exception of the battery, is subject to real repair. The plastic case and the power cord, the mount for the battery practically do not break if you do not drop the tool from a great height. Even so, the crack can be repaired with polyurethane or epoxy glue, and the cord can be simply replaced. If the crack is more than 4 cm, then along the edges of the crack, drill two rows of holes with a drill and pull off with a thin steel wire. This method of restoring the body of a power tool, despite its barbaric appearance, provides strength at a new level.
Any attempt to repair a screwdriver battery usually ends in failure of the charger or engine. Do not try to open the cylindrical cells of the battery, the lithium ion filling may ignite.
Repairing a screwdriver begins with disassembling the case. To do this, you need to unscrew several self-tapping screws, after which the screwdriver body is divided into two halves, opening up access for repair to all the main units of the power tool.
Most of the screwdrivers of popular brands are assembled using modular technology, from ready-made assemblies, so repairs in most cases are carried out according to the following scheme:
Dismantling the device, carrying out diagnostics and determining the parts necessary for repair;
Purchase of the kit necessary for the repair in the online store;
Transfer of mounting elements from a burnt-out part to a new one, installation in the housing and testing of the repaired part. If the parts were identified by the markings and the model of the screwdriver correctly, then the repair work will definitely be successful.
In some domestic models, you can perform a deeper repair of the planetary gearbox, for example, with the Caliber screwdriver, as in the video:
VIDEO
But in most cases, owners prefer to carry out SKD tool repairs.
The idea of a piece-by-piece repair has led to the fact that performing maintenance or replacing consumables in a screwdriver becomes a real problem.It is known that engine brushes have a certain resource, after which they need to be replaced. For example, if you are trying to replace brushes and repair a Makita screwdriver, then be prepared for the fact that it will be easier to buy and install a new motor than to find and replace old ones.
All Bosch power tools are renowned for their reliability. All the most important parts - the motor, the gearbox, the chuck - are manufactured with a large margin of safety, so the repair of a Bosch screwdriver is usually the result of improper handling or the result of force majeure. However, every Bosch screwdriver model has its weak points. For example, in the GSR 14.4 model, the weak point is the fastening of the chuck on the gearbox shaft; when trying to pull the drill out of the hole, the chuck can fly off the shaft.
In this case, the repair of the Bosch screwdriver is carried out according to the following scheme.
Initially, you need to disassemble the screwdriver body and pull out the monoblock "motor-reducer".
In order to gain access to the internal structure of the gearbox during diagnostics, you need to remove the fasteners and slightly turn the gearbox housing relative to the engine.
Next, the four steel spring clips are removed. After removing the gearbox, the reason for the repair becomes visible. This is a worn annular groove on the motor shaft into which a snap ring is inserted. The entire repair of a Bosch screwdriver boils down to deepening the groove with a cutter and assembling the tool in the reverse order, as in the video:
VIDEO
In principle, a not bad network screwdriver company Interskol has a drawback that is characteristic of most networked power tools. First of all, it is the short cord of the power tool. If you have to do roof repairs, you must pull on the carrier at the same time and be careful not to snag it on other tools during the repair process.
After several years of use, most corded screwdrivers require a cord revision. At some point, the Interskol screwdriver will need to be repaired, since the tool began to turn on only in one position. This is a typical sign of a broken contact on the power button. Before ringing the chain, you need to remove the housing mount and remove the cover.
The button is a box with a trigger and four screw contacts, two of which go to the speed regulator, the rest are used to connect the mains power supply. If you try to ring the cord with a tester, then one of the contacts will show a break. You should not disassemble the button itself, it is a fairly reliable unit, it very rarely fails, so any attempts to see what is inside usually end in breakdown. Disassembly of the button is necessary only if the trigger is not held by the latch, or the return spring is broken.
To repair a screwdriver, it is enough to loosen the screw clamps of the power cord contacts, cut 3-4 cm, clean and press the ends into brass clips, install them in the box contact sockets and fix with screws. You do not need to repair the cord, but simply replace it with a more convenient network cable in a soft rubber sheath of a suitable length and cross-section.
We should also mention the repair of the electric motor. Low-speed collector DC motors are used in almost all models of screwdrivers. In many cases, speed control is carried out using an electronic board that generates 12 V DC voltage pulses with different duty cycle. If the engine suddenly stops starting, do not rush to disassemble and repair it; in many cases, disassembly means its residual loss. Check the operation of the board, in 90 cases out of 100 the problem lies precisely in it.
there is a screwdriver arsenal clone makita. In the tightening mode, the gearbox is triggered by the slightest load, how to repair it?
This device is in the trash! Waste only time and money.
aleks mont, disassemble the ‘ratchet’, perhaps it’s a spring. And describe the problem in more detail.
Why mislead a person? Even if he finds a reason, what's next, which spring? The best way out is to buy a new shura, or put a gearbox from Makita, if it fits, of course. A waste of time.
a gearbox from Makita will do, I asked in the workshop, but naturally I will not buy it, I just want to understand the principle of operation of the gearbox
I'm not going to spend money on it, I don't mind spending a little time on the weekend
aleks mont wrote:
Any clutch position? Even in drilling mode?
in the first speed in any position of the clutch in the second speed everything is fine, but the shura does not pull the screw
The gears of the first gear sat down, most likely plastic. Disassemble to satisfy curiosity.
vasof wrote:
metal gears and what about rubbish you got excited
You can solve this problem only by replacing the gearbox, Makitovsky will cost 300-350 hryvnia, if it works at second speed, finish off the device and do not worry, it will not last long anyway.
Is the gearbox or the torque clutch defective? But everything was metal there. For clarity of the problem, post a photo of the faulty node, it can be a penny matter.
Video (click to play).
If this is a clone of makits, then it is quite possible that the teeth in the gearbox housing, which hold the large gear wheel, are licked (it transfers rotation to the second level of gears and when it scrolls the shura stops twisting at the same speed), such a problem often happens on makits after a year or two of active operation ...
