Hammer blow to the internal piston scuffing

Hammer blow weak factors many, as a lack of nitrogen pressure, energy storage is insufficient pressure, insufficient hydraulic pressure, but in relief as a piston or cylinder scuffing.
The main cause of piston galling following introduction.
Piston as broken hammer core parts and accessories, special effect, however, produced with imported piston longitudinal strain is more controversial, therefore, the author summarizes some experience, analyzes the piston scuffing, hoping to give some tips for the majority of users.
(1) hydraulic oil is not clean
In the oil such as impurities, these impurities a wedge gap piston and a cylinder, can lead to injury. The strain has the following characteristics: generally have more than 0.1mm deep grooves, fewer in number. Its length is approximately equal to the piston stroke.
(2) the clearance between the piston and the cylinder is too small.
This situation often occurs in a new piston replacement, if the gap is too small hydraulic breaking hammer at work, as the temperature increases and changes a gap, then of the piston and the cylinder is easy to cause injury. The characteristics are: the depth of the drawing trace is shallow, the area is large, and its length is about equal to the stroke of the piston.
(3) the hardness of the piston and cylinder is low
Due to the low hardness of the surface of the piston and the cylinder, the piston is subjected to external force. The characteristics are: the depth is shallow and the area is large.
(4) rod guide sleeve failure
Guide sleeve of poor lubrication or because of poor guide sleeve wear resistance, accelerate the guide sleeve wear and drill rod and a guide sleeve gap sometimes up to more than 10mm, then the central line of the drill rod easily skew, when at the end of the piston moves to the drill rod, piston by the reaction is an eccentric force, are a component of this force is formed the radial force acting on the piston, piston in radial force under the action of inclined to one side, the original gap disappeared, the oil film is damaged, forming dry friction, soon the piston in the cylinder, and the surface strain. Its characteristics is that strain area larger, about is about 1 / 3 of the cylindrical area, shorter traces of strain, equal to the displacement amount of the drill rod.
(5) improper repair methods
Not only can cause the piston and the cylinder of a strain, and can even cause more serious consequences. We in to a unit repair of hydraulic breaking hammer found cylinder stepped hole, big hole near the small hole end has great taper, than the average size of small 0.28mm, a big hole and a small hole axiality deviation of more than 0.15mm. As far as we know, the user in the repair of used honing method attempts to repair strained cylinder, and the preparation of a new piston. Results in the test of life SecA death. After the disintegration of the piston and cylinder found a large area of injury, the reason is improper repair methods. To pull or wear and tear of the ladder hole is not in honing way repair, because the honing head structure is suitable for the grinding and stepped holes and because the honing tool relative to the workpiece is floating, so honing is not suitable for repair of hydraulic hammer has strain of the cylinder block.