Hammers Hitachi – Fault finding and repair

At first glance, repairs perforator Hitachi DH24 with their hands may seem daunting, but became acquainted with the scheme and perforating gun disassembled instruction Hitachi DH24PC3.Perforator Hitachi DH24PC3 is a fairly simple structure, no special skills required to carry out repairs, only need the appropriate tool. The only requirement, perform disassembly and assembly of the gun in a certain sequence.

Structurally made by Hitachi perforator block diagram. The composition includes a mechanical tool unit, the stator unit and the control circuits.

Faults mechanical perforator Hitachi DH24PC3

Hammers Hitachi is a reliable tool, easy to use, are in high demand among professionals and among the Russian masters and lovers of tinkering with his own hands.

But every time the instrument is operated with a maintenance-free, Periodic inspection and, if necessary, repairs.

Any punch found three main types of faults:

• malfunction, hammer drills in which, but do not hammer;
• malfunction, in which the hammer drill, but do not drill;
• malfunction, in which the punch is not hammer and drill.

malfunctions, hammer drills in which, but do not hammer

The process of drilling a Hitachi rotary hammers is provided by transmitting torque from the rotor, via an intermediate shaft to the hammer barrel.

chipping process is provided by converting the torque of the intermediate shaft into reciprocating via rolling bearing, Popularly known as "drunk bearing".

Shock pulse is created by moving the striker in the sleeve of the piston and the hammer barrel. drunk bearing, mounted on the intermediate shaft converts the rotating motion into reciprocating.

causes, which can drill punch, but do not hammer, can be:

• Bearing drunken destruction;
• trunk piston sleeve destruction;
• seizure or destruction of the strikers;
• rotation of the clutch in a drunken bearing;
• wear rubber O-rings.

With the destruction of the bearing becomes impossible drunk converting torque into reciprocating impulse. But at the same time, the rotation of the barrel is transmitted due to the gears. More complete instructions for disassembling the gun Hitachi.

Repair drunken bearing and the clutch or replace them

Yield drunk bearing failure occurs in the destruction of the bearing holder embedded. This problem has been solved only complete replacement drunken bearing. The perforator Hitachi DH24PC3 mounted bearing article 324533. Russian analog of the present bearing no, but Chinese-made bearings are available, good quality.

To replace the rolling bearing must be removed from the inner intermediate shaft perforator housing.

drunken bearing dismantling is done in conjunction with the clutch. Ruined drunk bearing poz.53 can not be restored, but the clutch poz.52 with a slight worn splines engagement can restore.

Repair or replacement of the piston sleeve

Dropouts can occur pin fracture piston sleeve poz.39. In the piston sleeve can fall off the mounting lugs of the piston pin poz.42. In the piston skirt sleeve collapses, the thin portion of the piston. there are cases, that the sleeve bites striker percussion mechanism poz.37.

With the destruction of parts of the piston sleeve made its complete replacement. Repair sleeve piston is practically impossible.

Repair impactor strikers

In the trunk of the striking mechanism used two types of strikers. Poz.37 striker sleeve and the hammer peen cylinder barrel poz.29.

On striker poz.37 rubber ring set key. 38, and mounted on the striker poz.29 rubber ring poz.30. rubber and oil seal poz.32.

Besides, on the striker poz.29 set holder impactor poz.31, on both sides of which are placed O-rings poz.30, 32. Then on the striker damper mounted holder poz.35, a locking ring which is fixed poz.36. Poz.34 - a rubber sealing gland.

The main failure of the strikers is to wear them, deterioration of the O-rings in the process of shocks. The striker can bend, flatten.

Failures of this kind eliminates replacement parts shock mechanism and be sure to replace all rubber O-rings.

To purchase a new spare parts, We need to know the details of the ordered articles, which are indicated in the pictures.

Repair coupling intermediate shaft clutch

When the punch in "Blow" mode, do not try to press hard on the tool.

By the disappearance of a shock pulse causes slipping clutch pos 51 on the intermediate shaft poz.52.

We clutch at the hard work to lick their teeth. This occurs when the elevated pressure on the work tool while performing work or weakening of the spring pressure force on clutch poz.50.

Recover the tooth profile can be using Needle. If the tooth is not much to lick, the circular needle files tooth profile corrected by reduction of its corners on the clutch shaft and the intermediate poz.52. Otherwise, should be replaced with a strong wear.

Replacing the rubber O-rings

In the shock pulse providing a chain mechanism uses several sealing rings.

Dropouts shock pulse to the end effector occurs due to abrasion of sealing rings. A problem occurs gradually, as the seals wear.

malfunctions, in which the hammer drill, but do not drill

Chiseling perforator Hitachi DH24PC3 occurs due to transfer reciprocating motion of the intermediate shaft through the rolling bearing on the cylinder, moving to the hammer barrel. The punch cylinder is equipped with two firing pin. Here the movement of the striker and transmits the shock pulse on the table, in which the keyless chuck, inserted working tool, eg, Boer.

The process of drilling a Hitachi DH24 perforators ensured by transmitting torque from the rotor, via an intermediate shaft to the hammer barrel. At the end of the barrel is mounted keyless chuck, which is installed and working tool.

Helical poz.62 rotor gear transmits torque to the larger diameter helical gear poz.54, mounted on the intermediate shaft poz.51. The rotating intermediate shaft transmits its small spur gear torque to a large spur gear poz.25, fixed to the striking mechanism barrel.

Drilling in punch Hitachi DH24 occurs due to rotation of the keyless chuck, wherein the fixed drill or drill.

A malfunction of this kind leads:

• - rotation of the gears on the intermediate shaft poz.49 poz.52;
• - cranking gears poz.25 on poz.24 stem shaft.

Inspection of gears on the intermediate shaft

Poz.49 gear can rotate on the intermediate shaft due poz.52 weakening the pressing force of the spring poz.50 and malfunction mode switch poz.48.

This fault Punch Hitachi eliminated by reduction of the splines on the pinion 5 and wave.

Restore slots with little wear and tear, you can use the correction form tooth slot. To do this, using a circular needle files, clamped in the drill chuck, correct tooth contours.

Recover operation mode switch 4 You can only complete its replacement.

Repair of the striking mechanism barrel pinion

Poz.25 gear mounted on the shaft section and fastened there by a spring at 26, fixed locking ring and washer pos.28 steel M30 poz.27.

With the weakening of the spring force at 26 pops out of gear engagement and rotated.

Troubleshoot this kind of replacement for the spring and the correction form engaging teeth.

Faults electrical

When a fault occurs in the electrical part of the punch tool stops working completely.

malfunctions, in which the punch does not drill or hammer

reasons, in which the punch stops working, relate:

• destruction of small helical teeth of the rotor gear;
• failure of the rotor;
• short circuit or open circuit in the stator;
• open or short circuit in the control circuit.

Repair of the rotor

With slight wear helical gear failure is eliminated by reduction of tooth forms, if possible. Otherwise, reducer must be replaced completely.

If a short circuit or breakage of the rotor winding, failure of the commutator bars, the gearbox can be repaired or replaced with their hands on the new. New is quite expensive. And to make the rotor with your hands is not everyone's strength. The choice is yours. Learn more about, how to repair the rotor with your hands, you can read in our papers.

stator Repair

Repair of the stator is made in detection of a short circuit or an open. repair the stator not difficult, if you know the number of turns, conductor cross-section and its brand.

If you have burned the stator, or found in it open, when the disassembly make a count of the number of turns and measure micrometer section. Note the percentage of filling the stator winding slots. When filling small percentage can increase the diameter of the winding wire.

Inspection of the electrical part of the control

Of faults in the control circuits is most often manifested in the power cable breakage at the entry site in the tool and the failure of the start button.

The tool uses a combination switch, allows you to run the punch and adjust the speed rate. The punch used pushbutton 220 AT (OLD 331454/324536).

Carbon brushes poz.74, 77 fixed in special holders poz.75. short-circuiting control circuits cause may be poz.69 choke and a diode contact poz.72. Important monitor the size of the brush and replace them in time.

The article describes the main types of faults in rotary hammers Hitachi DH24PC3. If you are faced with other failures, or know how to fix them, write to us.

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