Modern set of repair and construction equipment is hard to imagine without such an important tool as a hammer drill. The principle of its operation is based on the functions of a conventional electric drill, which are expanded by reciprocating impact capabilities. A special mechanism is responsible for them, which converts the rotational movements of the shaft into shock. If a hammer drill needs to be repaired, then most often it is this node that fails, because it is subjected to increased loads.
Punch design features
The shock function in the electric puncher is provided by a special pneumomechanical assembly. However, there are also models of perforators in which a mechanical or electrical system is responsible for the impact. It should be noted that these tools are inferior in accuracy and performance to electric hammers with a pneumatic blow formation system.
The design of perforators has its own characteristics, one of which is the use of extra strong drills instead of conventional drills. Due to its special shape, the drill is able to withstand greater longitudinal loads than a drill with a percussion mechanism. The drill does not have a sharp cutting edge on the working end - it is replaced by a carbide tip. Meanwhile, the design of the drill provides spiral longitudinal grooves, similar to the grooves of conventional drills. However, they are intended for the removal of crushed waste material in the process of drilling a hole. To do this, the perforator drill performs, in addition to reciprocating, also rotational movements around its own longitudinal axis, which also contribute to the straightness and centering of the drill in the material.
The chuck and shank of the drill are designed in such a way that it is not rigidly fixed, but has some freedom of longitudinal movement. This is done in order to prevent the loss of kinetic energy of impact to accelerate the cartridge, increase productivity and reduce the vibration level of the punch.
Strong pollination is one of the main causes of tool breakage, and the chuck, in addition to heavy load, also takes on the main part of the dust. So that the repair of the punch cartridge does not turn into a chronic problem, it must be periodically cleaned of dust and dirt. Washing with gasoline or cleaning with compressed air is recommended. After cleaning, all elements of the cartridge should be re-lubricated.
Punch reducer
Reducer transmits torque from the engine to the impact mechanism of the perforator. It is a set of cylindrical, bevel and worm gears. The speed of rotation of the cartridge and the number of strokes are changed using electronic controllers. There are also models equipped with a two-speed gearbox.
The gearbox needs to be lubricated periodically and the use of greases is recommended for this. They are refilled when assembling, maintaining or repairing the rock drill gearbox.
Main causes of breakdowns
As already mentioned, one of the main causes of breakdowns of most of the puncher units is heavy dusting. For example, a collector motor is cooled by a fan, which, together with air, delivers dust particles to the motor. As a result of the friction of these particles on the armature and stator, these mechanisms wear out quickly.
If the tool does not turn on, one of the reasons may be damage to the winding, then the repair of the puncher is inevitable - you will have to rewind the stator and armature.
Also, frequent breakdowns are associated with mechanical assemblies of punchers. Most models are equipped with mechanisms for switching operating modes (rotation, fight, rotation with fight). If at least one of these functions has stopped working, the switch is most likely to blame. To fix the breakage, disassembly of the tool will be required.
Do-it-yourself puncher repair: is it worth the risk?
Most users are convinced of the inexpediency of repairing cheap models of rotary hammers. Such a skeptical attitude is explained by the imperfection of the design of inexpensive, as a rule, Chinese models. But if some insignificant detail has broken, this does not mean at all that you should immediately run to the store for a new tool. Currently, you can easily purchase all kinds of spare parts for any models of rotary hammers. Another reason for not wanting to repair a rotary hammer with your own hands is the fear of not understanding the complex mechanism. Of course, such concerns are justified. After all, if the user does not know the perforator device perfectly, he will not be able to do repairs on his own. In this case, of course, it makes sense to contact a specialized workshop. Be that as it may, do not rush to put an end to your tool, because any repair will be cheaper than a new hammer.
Disassembly order
If you still decide to repair the hammer drill on your own, then the tool should be disassembled in the following order:
- Carefully remove the shift lever.
- Remove the rubber cap.
- Disassemble the cartridge: remove the brushes, unscrew the screws and disconnect the body.
- Inspect, clean parts, replace faulty elements (brushes, bearings, gears, armature, etc.), lubricate all rubbing units (CV joint grease is not recommended).
Assemble the tool in reverse order.
Symptomsmalfunctions
But how to understand that the repair of the puncher is required? Of course, the simplest sign is the inability to turn on the tool. However, any other, even minor changes in the operation of the device should not be ignored. This, for example, can be changes in sounds at idle or during operation, sparks from the engine, smoke, burning smell, jerks of working bodies, sudden periodic stops, and other symptoms. All this indicates problems that must be immediately eliminated in order to avoid global breakdowns and costly repairs.
