A tool for a hydraulic hammer of a work machine is disclosed herein. The tool comprises a spline section and a tool section. The spline section includes a first spline sector including at least six spline grooves and a second spline sector including at least six spline grooves. The first spline sector and second spline sector are separated by a spacer. The tool section diameter is 3.2-4.8 times larger than the spline groove diameter and the tool section diameter is smaller than a spline section diameter.

Provided is a hydraulic hammering device having improved hammering efficiency and of low cost. A piston has a valve switching groove between large-diameter sections thereof. A cylinder has three control ports at positions corresponding to the valve switching groove. A switching valve mechanism has a valve presser for always pressing a valve in one direction and also has a valve controller for moving, when supplying pressurized oil, the valve in the opposite direction against the pressing force of the valve presser. A valve control port communicates with the valve controller so as to supply the pressurized oil to the valve controller and is separated from a piston front chamber and a piston rear chamber. Only either a piston retraction control port or a piston advance control port communicates with the valve control port depending on advance or retraction of the valve switching groove.

A hydraulic hammer includes a housing and a plurality of splines. The housing defines a chamber extending along a longitudinal axis configured to receive a tool. The splines are disposed on an inner surface of the chamber and extend parallel to the longitudinal axis. Each of the splines has a contact surface configured to slidably guide the tool when disposed within the chamber. A treated layer is applied to the contact surface of each spline, the treated layer configured to withstand approximately between 100 MPa to 320 MPa of pressure applied during an operation of the hydraulic hammer without galling. An interface is defined between the contact surface of the splines and a surface of the tool and is configured to facilitate sliding engagement between the treated layer of the contact surface of the splines and the surface of the tool without lubricant during the operation of the hydraulic hammer.

A piston guiding element, rock drilling machine and method for supporting a front end portion of a percussion piston of a rock drilling machine. The piston guiding element includes a braking recess at its rear end. The element further includes at least one bearing sleeve, which is provided with two axially successive slide bearing sections. Hydraulic fluid is conveyed between the slide bearing sections via a feed system.