Rotation unit, rock drilling unit and method for rock drilling

Abstract

A rotation unit, rock drilling unit and method for rock drilling. The rotation unit includes a main shaft that is rotated around its longitudinal axis by means of a rotating motor. The main shaft is supported on a body of the rotation device slidingly in the axial direction. This slide property is utilized when connection threads of drilling equipment and drilling components comprised by it are connected.

1 . A rotation unit for rock drilling comprising:
 a body;   a main shaft of an elongated piece having a front end with connection means for attaching drilling equipment and an opposite rear end, supported in the body and having at least two bearings rotatable in relation to its longitudinal axis, wherein an outer periphery of the main shaft includes at least one feed flange having axial support surfaces, the body including, at the location of the feed flange, an annular sliding space surrounding the main shaft and having an axial length, wherein the sliding space is defined by an axial front end and a rear end having support surfaces, the support surfaces of the feed flange and sliding space being arranged to transmit axial forces between the body and the main shaft, wherein the feed flange and the sliding space are positioned at the front end of the main shaft;   a rotating motor;   transmission members for transmitting rotation force from the rotating motor to the main shaft;   axial support surfaces for transmitting axial forces between the body and the main shaft in a drilling direction and a return direction;   channels for conducting a pressure medium to the main shaft and to the drilling equipment, wherein the main shaft is slidably supported on the body in an axial direction; and   a front bearing disposed around the front end of the main shaft in the sliding space, the front bearing being positioned in a portion between the feed flange and the rear end of the sliding space,wherein the front bearing is a slide bearing slidably arranged in the sliding space in the axial direction.   
     
     
         2 . A rotation unit as claimed in  claim 1 , wherein the main shaft is supported in the body in a radial direction by a front bearing in the portion of the front end and by an end bearing in the portion of the rear end, wherein the front bearing and the end bearing are slide bearings. 
     
     
         3 . A rotation unit as claimed in  claim 1 , wherein the transmission members comprise sliding members which allow axial movement of the main shaft without transmitting axial forces. 
     
     
         4 . A rotation unit as claimed in  claim 1 , wherein a rotation force is transmitted to the main shaft from the portion of the rear end. 
     
     
         5 . A rotation unit as claimed in  claim 1 , wherein the rotating motor is positioned on the side of the rear end of the main shaft, wherein the rotating motor and the main shaft are arranged on the same axial line. 
     
     
         6 . (canceled) 
     
     
         7 . (canceled) 
     
     
         8 . A rotation unit as claimed in claim  claim 1 , further comprising an axial damper integrated with the rotation unit for damping axial stresses affecting the main shaft, the axial damper comprising at least one end damper arranged at the axial end of the sliding space. 
     
     
         9 . A rotation unit as claimed in  claim 8 , wherein the end damper made of a compressive elastic material. 
     
     
         10 . A rotation unit as claimed in  claim 1 , wherein the connection means disposed at the front end of the main shaft is a connection thread, whereby the connection between the rotation unit and the drilling equipment is rigid in the axial direction. 
     
     
         11 . A rotation unit as claimed in  claim 1 , wherein the main shaft has a first main shaft part and a second main shaft part arranged on the same axial line and connected to each other with an axially rigid connection, the outer periphery of the rear end of the first main shaft part having a set of grooves for transmitting rotation force, the first main shaft part being bearing-mounted on the body by the ends thereof by a front bearing ( 22 ) and an end bearing, and the front end of the second main shaft part including a connection thread for attaching the drilling equipment. 
     
     
         12 . A rotation unit as claimed in  claim 1 , wherein the main shaft is bearing-mounted on the body by a front bearing and an end bearing which have an axial bearing distance (L) and at the point of the bearings the main shaft has a first and second diameter, the ratio of the bearing distance to the greater one of the first or second diameter being at least 3:1. 
     
     
         13 . A rock drilling unit comprising:
 a rotation unit having a rotating motor for generating rotation force, a main shaft to which rotation force is transmitted by means of transmission members, and connection members for attaching drilling equipment to the main shaft, the rotation unit having a body and a a main shaft of an elongated piece having a front end with connection means for attaching drilling equipment and an opposite rear end supported in the body and having at least two bearings rotatable in relation to its longitudinal axis, wherein an outer periphery of the main shaft includes at least one feed flange having axial support surfaces, the body including, at the location of the feed flange, an annular sliding space surrounding the main shaft and having an axial length, wherein the sliding space is defined by an axial front end and a rear end having support surfaces, the support surfaces of the feed flange and sliding space being arranged to transmit axial forces between the body and the main shaft, wherein the feed flange and the sliding space are positioned at the front end of the main shaft and a front bearing is disposed around the front end of the main shaft in the sliding space, the front bearing being positioned in a portion between the feed flange and the rear end of the sliding space,wherein the front bearing is a slide bearing slidably arranged in the sliding space in the axial direction   a feed beam by the support of which the rotation unit is movable in a drilling direction and a return direction;   a feed device for generating feed forces; and   drilling equipment including at least one drilling tube, a first end connected to the rotation unit for transmitting the feed forces and rotation forces to the drilling equipment, and a free end having a drill bit for breaking rock.   
     
     
         14 . A rock drilling unit as claimed in  claim 13 , further comprising a percussion device arranged in the portion of the free end of the drilling equipment, wherein the drill bit is connected to the percussion device. 
     
     
         15 . A rock drilling unit as claimed in  claim 13 , further comprising a carriage which is movable on the feed beam, wherein the body of the rotation unit is immovably attached to the carriage. 
     
     
         16 . A rock drilling unit as claimed in  claim 13 , further comprising at least one sensor for determining the axial position of the main shaft of the rotation unit. 
     
     
         17 . A method for drilling rock, comprising the steps of:
 drilling rock with a rock drilling unit which comprises at least a rotation unit, a feed beam, a feed device and drilling equipment;   rotating a main shaft of the rotation unit around its longitudinal axis and transmitting rotational motion to the drilling equipment connected to the main shaft, the outermost end of which drilling equipment includes a drill bit for breaking rock;   feeding the rotation device by the feed device, supported by the feed beam, in a drilling direction and a return direction;   connecting the drilling equipment to the main shaft by a connection thread and connecting drilling components of the drilling equipment to each other with connection threads disposed between them; and   allowing the main shaft of the rotation unit to move axially in relation to a body of the rotation unit when the drilling equipment and components of the drilling equipment are connected and disconnected.