12.2.4 Conclusions
(1) Hydraulic–pneumatic composite hammering technology can realize the hammering ability of hydraulic hammer with acceleration of more than 1 g. The
average acceleration of the example can reach 1.8 g. Hydraulic–pneumatic
composite technology has higher strike frequency and energy under the same
stroke and hammer weight.
(2) The accumulator of hydraulic hammer plays an important role in reducing
pressure fluctuation and increasing strike frequency.
(3) Hydraulic cylinder piston, piston rod diameter, nitrogen chamber initial
pressure and volume, high and low-pressure accumulator initial pressure and
volume parameters directly affect the strike energy of hydraulic hammer,
through appropriate parameter design and cooperation to achieve a better
design and use effect of hydraulic hammer.
Time t/s
Strike energy /(kN
m)
Fig. 12.11 Strike energy–time curves for a working cycle
Table 12.3 Comparison of design and simulation values
Comparison
items
Design
value
Theoretical
value
Comparison
items
Design
value
Theoretical
value
Strike energy
600 kN m
633.3 kN m
Descending
journey
1.2 m
1.4 m
Strike
frequency
45 Hz
44 Hz
Average
acceleration
2 g
1.84 g
12.2 High-Speed Pneumatic–Hydraulic Composite Hammer
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