Reference Materials; Lubrication; Tool Structure - Hitachi DH 22PG Technical Data And Service Manual

Hitachi rotary hammer technical data and service manual

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Handling instructions manual (81 pages)

Instruction manual (52 pages)

Handling instructions manual (39 pages)

Table Of Contents

Table of Contents

1. Lubrication

Replenish the grease lubricant when the tool is disassembled or there is grease leakage due to a defective

seal. Changing grease is required once a year to extend the service life of the tool. Special grease is used

in the striking section. Should the striking section (within the gear cover) be disassembled, remove the old

grease from all parts completely and, on reassembly, replenish 30 g of new grease in the gear cover and 10

g in the groove of the inner cover. Be careful not to exceed the designated amount of grease. Excessive

grease will reduce striking efficiency.

2. Tool structure

Transmission of rotation

See Fig. 2. The rotation of the armature is transmitted to the second shaft via the first gear, and causes

it to rotate. The second shaft pinion mounted on the second shaft engages with the second gear

mounted on the outer circumference of the cylinder. The cylinder is coupled to the second gear by

means of a slip mechanism, and they rotate together. The end of the cylinder also functions as the drill

bit retainer. The cylinder is key-connected to the inserted drill bit by means of two key rails and a steel

ball, and transmits rotation to the drill bit.

Piston reciprocating mechanism

In the Model DH 22PG, through adoption of a spiral drive system (a mechanism using a reciprocating

bearing), a more compact design has been achieved by arranging the motor shaft in parallel with the

tool shaft. Figure 2 shows that the drill bit is pressed against the workpiece and the tool shaft is

retracted. The rotation of the armature is transmitted to the second shaft via the first gear. The second

shaft rotation is further transmitted through a spline to the clutch. The cylinder flange is pressed against

the clutch by the retracted tool shaft and the clutch engages with the reciprocating bearing to transmit

rotation to the reciprocating bearing. However, ring grooves on the inner race of the reciprocating

bearing are positioned on an angle of inclination with relation to the second shaft.

Fig. 2

Piston pin

Armature

Motor shaft

First gear

Ringed ditch

Ring groove

The rotation of the inner race and the shaft causes that angle of inclination to change regularly forward

and backward with relation to the second shaft, and produces a rocking motion to the outer race of the

reciprocating bearing. Finally, a rod extending from the outer race of the reciprocating bearing is

connected to the piston by the piston pin, and causes the reciprocating bearing motion of the piston.