Hydraulic brake for drilling-bit

Abstract

Method for blocking/braking at least one conical inlet wheel of a drilling-bit of a drilling tool, said method consisting in using at least one toothed wheel ( 1 ) of said drilling-bit as an element for driving a hydraulic pump (P) which pumps in a closed circuit ( 17 ), said circuit including a controlled distributor ( 9 ) in order to take up either an open position or a closed position; such that, in the open position, the pump runs freely without absorbing energy, and that, in the closed position, said pump (P) is hydraulically blocked, which blocks the rotation of the toothed wheel ( 1 ).

1 . Method for controlling a toothed wheel of a drilling-bit, in which method the toothed wheel ( 1 ) of said bit is used as an element for driving a hydraulic pump (P) which pumps in a closed loop hydraulic circuit ( 7 ), said circuit including a controlled sealing member ( 9 ), the method including the steps of:
 controlling the sealing member in a forward direction in order to suppress the hydraulic braking force exerted onto the toothed wheel ( 1 ), and   controlling the sealing member in a reverse direction in order to increase the hydraulic braking force exerted onto the toothed wheel ( 1 ).   
     
     
         2 . Method according to  claim 1 , in which the drilling-bit is rotated, the method including phases for braking the toothed wheel alternated with phases for releasing the toothed wheel. 
     
     
         3 . Drilling-bit including a drilling pipe ( 20 ), three toothed wheels ( 1 ) mounted in a pivoting manner on said drilling pipe and at least three hydraulic brakes arranged in the drilling pipe ( 20 ), in which each hydraulic brake includes a closed loop hydraulic circuit ( 7 ), a hydraulic pump (P) arranged in the closed loop hydraulic circuit in order to suck up a hydraulic fluid in a first portion ( 8 ) of the hydraulic circuit and to pump out the hydraulic fluid in a second portion ( 6 ) of the hydraulic circuit and a controlled sealing member ( 9 ) arranged in the closed loop hydraulic circuit between the first portion and the second portion, the hydraulic pump (P) including a rotary pumping member coupled to one of said toothed wheels ( 1 ) in order to rotate integrally with said toothed wheel. 
     
     
         4 . Drilling-bit according to  claim 3 , characterized in that the pump (P) is a pump with axial pistons ( 15 ) which are driven by a swash plate ( 11 ), the swash plate forming the rotary pumping member of the pump and including a shaft ( 13 ) which is integral with the toothed wheel ( 1 ). 
     
     
         5 . Drilling-bit according to  claim 4 , characterized in that the shaft ( 13 ) of the swash plate ( 11 ) is fixed in an axial bore ( 14 ) which is provided in a cylindrical support ( 3 ) of the toothed wheel ( 1 ). 
     
     
         6 . Drilling-bit according to  claim 3 , characterized in that the pump (P) is a pump with radial pistons which are driven by a cam which is integral with the toothed wheel ( 1 ). 
     
     
         7 . Drilling-bit according to  claim 3 , characterized in that the pump (P) is a geared pump or another flow generator. 
     
     
         8 . Drilling-bit according to  claim 3 , characterized in that the sealing member ( 9 ) is controlled in an electric or mechanical manner. 
     
     
         9 . Drilling-bit according to  claim 3 , characterized in that the sealing member ( 9 ) includes a distributor having a forward state as default. 
     
     
         10 . Drilling-bit according to  claim 3 , in which the hydraulic brake includes a pressurized and pressure-compensated hydraulic fluid reservoir ( 19 ) connected to the first portion ( 8 ) of the hydraulic circuit ( 7 ). 
     
     
         11 . Drilling-bit according to  claim 3 , including three toothed wheels and three hydraulic brakes in order to brake the rotation of each of said toothed wheels independently.