Reference Material; Lubrication; Tool Structure - Hitachi DH 24PB3 Technical Data And Service Manual

8. REFERENCE MATERIAL

8-1. Lubrication

It is not necessary to replenish the grease lubricant unless the tool is disassembled or there is grease leakage
due to a defective seal. Special grease is used in the striking section. Should the striking section (within the gear
cover) be disassembled, carefully remove the old grease from all parts and, on reassembly, insert 45 g (1.6 oz) of
new grease into the gear cover and 5 g (0.2 oz) into the groove of the inner cover. Be careful not exceed the
designed amount of grease. Excessive grease will reduce striking efficiency.
Apply Molub Alloy No. 777-1 grease to the outer circumference of the clutch groove and the pin portion of the
change lever.

8-2. Tool Structure

While the structure is essentially the same as the Model DH 24PB2, the descriptions below are included to
enhance your understanding of the tool and its mechanisms.
Transmission of rotation
Unlike conventional rotary hammers, the armature shaft in the Model DH 24PB3 is in parallel with the tool
shaft - the same structure that is employed in most impact drills. This structure was adopted in order to make
the Model DH 24PB3 more compact for easier handling and operability. Thus, the appearance of the Model
DH 24PB3 is similar to that of an impact drill. The rotation of the armature is transmitted to the second shaft
via the first gear, and causes it to rotate. The second pinion provided on the second shaft engages 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 transmits rotation
to the drill bit. A steel ball is used to prevent the bit from falling.
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