Drilling tool and drilling method

Abstract

A drilling tool of the invention includes an air supply pipe inserted through an inner circumference of a drilling pipe having a tip portion on which a tool main body is disposed. The air supply pipe being configured to supply compressed air. A supply channel is provided on an outer circumference of the drilling pipe. A discharge channel is formed on the tip portion of the tool main body. The discharge channel is configured to discharge cuttings generated together with the drilling fluid into a space between the drilling pipe and the air supply pipe. An exhaust gas outlet opening into the space is formed at a tip portion of the air supply pipe.

1 . A drilling tool comprising:
 a tool main body;   a drilling pipe having a tip portion on which the tool main body is provided; and   an air supply pipe configured to supply a compressed air and inserted through the drilling pipe, wherein   a supply channel is provided on an outer circumference of the drilling pipe, the supply channel being configured to supply drilling fluid to a tip portion of the tool main body,   a discharge channel is formed on the tip portion of the tool main body, the discharge channel being configured to discharge cuttings generated during drilling together with the drilling fluid supplied from the supply channel into a space between the drilling pipe and the air supply pipe, and   an exhaust gas outlet opening into the space is formed on a tip portion of the air supply pipe.   
     
     
         2 . The drilling tool according to  claim 1 ,
 wherein the exhaust gas outlet extends toward an outer peripheral side of the tool main body so as to incline toward a posterior end side of the tool main body and opens into the space.   
     
     
         3 . The drilling tool according to  claim 1 , further comprising a supply pipe through which the drilling pipe is inserted,
 wherein the supply channel is formed between the supply pipe and the drilling pipe.   
     
     
         4 . The drilling tool according to  claim 1 , wherein
 a plurality of grooves are formed on an outer circumference of the tip portion of the tool main body, the grooves extending from a tip of the tool main body toward the posterior end side of the tool main body,   some of the plurality of grooves communicate with the supply channel,   the remainder of the grooves communicate with the discharge channel, and   tip portions of the grooves which are communicated with the supply channel and tip portions of the grooves which are communicated with the discharge channel communicate with each other via a communicating groove formed on a tip surface of the tool main body.   
     
     
         5 . The drilling tool according to  claim 1 , wherein
 a groove is formed on an outer circumference of the tip portion of the tool main body, the groove extending from a tip of the tool main body toward the posterior end side of the tool main body to communicate with the supply channel,   a hole as the discharge channel is formed in the tool main body inside than the groove, the hole extending from the tip of the tool main body toward the posterior end side of the tool main body, and   a tip portion of the groove and a tip portion of the hole communicate with each other via a communicating groove formed on a tip surface of the tool main body.   
     
     
         6 . A drilling method using the drilling tool according to  claim 1 , the method comprising steps of:
 forming a borehole using the tool main body while supplying the drilling fluid to the tip portion of the tool main body through the supply channel;   discharging the cuttings generated during forming the borehole together with the drilling fluid through the discharge channel into the space between the drilling pipe and the air supply pipe; and   discharging the cuttings and the drilling fluid discharged into the space toward a posterior end side of the tool main body using the compressed air discharged from the exhaust gas outlet.   
     
     
         7 . The drilling tool according to  claim 2 , further comprising a supply pipe through which the drilling pipe is inserted,
 wherein the supply channel is formed between the supply pipe and the drilling pipe.   
     
     
         8 . The drilling tool according to  claim 2 , wherein
 a plurality of grooves are formed on an outer circumference of the tip portion of the tool main body, the grooves extending from a tip of the tool main body toward the posterior end side of the tool main body,   some of the plurality of grooves communicate with the supply channel,   the remainder of the grooves communicate with the discharge channel, and   tip portions of the grooves which are communicated with the supply channel and tip portions of the grooves which are communicated with the discharge channel communicate with each other via a communicating groove formed on a tip surface of the tool main body.   
     
     
         9 . The drilling tool according to  claim 3 , wherein
 a plurality of grooves are formed on an outer circumference of the tip portion of the tool main body, the grooves extending from a tip of the tool main body toward the posterior end side of the tool main body,   some of the plurality of grooves communicate with the supply channel,   the remainder of the grooves communicate with the discharge channel, and   tip portions of the grooves which are communicated with the supply channel and tip portions of the grooves which are communicated with the discharge channel communicate with each other via a communicating groove formed on a tip surface of the tool main body.   
     
     
         10 . The drilling tool according to  claim 7 , wherein
 a plurality of grooves are formed on an outer circumference of the tip portion of the tool main body, the grooves extending from a tip of the tool main body toward the posterior end side of the tool main body,   some of the plurality of grooves communicate with the supply channel,   the remainder of the grooves communicate with the discharge channel, and   tip portions of the grooves which are communicated with the supply channel and tip portions of the grooves which are communicated with the discharge channel communicate with each other via a communicating groove formed on a tip surface of the tool main body.   
     
     
         11 . The drilling tool according to  claim 2 , wherein
 a groove is formed on an outer circumference of the tip portion of the tool main body, the groove extending from a tip of the tool main body toward the posterior end side of the tool main body to communicate with the supply channel,   a hole as the discharge channel is formed in the tool main body inside than the groove, the hole extending from the tip of the tool main body toward the posterior end side of the tool main body, and   a tip portion of the groove and a tip portion of the hole communicate with each other via a communicating groove formed on a tip surface of the tool main body.   
     
     
         12 . The drilling tool according to  claim 3 , wherein
 a groove is formed on an outer circumference of the tip portion of the tool main body, the groove extending from a tip of the tool main body toward the posterior end side of the tool main body to communicate with the supply channel,   a hole as the discharge channel is formed in the tool main body inside than the groove, the hole extending from the tip of the tool main body toward the posterior end side of the tool main body, and   a tip portion of the groove and a tip portion of the hole communicate with each other via a communicating groove formed on a tip surface of the tool main body.   
     
     
         13 . The drilling tool according to  claim 7 , wherein
 a groove is formed on an outer circumference of the tip portion of the tool main body, the groove extending from a tip of the tool main body toward the posterior end side of the tool main body to communicate with the supply channel,   a hole as the discharge channel is formed in the tool main body inside than the groove, the hole extending from the tip of the tool main body toward the posterior end side of the tool main body, and   a tip portion of the groove and a tip portion of the hole communicate with each other via a communicating groove formed on a tip surface of the tool main body.   
     
     
         14 . A drilling method using the drilling tool according to  claim 2 , the method comprising steps of:
 forming a borehole using the tool main body while supplying the drilling fluid to the tip portion of the tool main body through the supply channel;   discharging the cuttings generated during forming the borehole together with the drilling fluid through the discharge channel into the space between the drilling pipe and the air supply pipe; and   discharging the cuttings and the drilling fluid discharged into the space toward a posterior end side of the tool main body using the compressed air discharged from the exhaust gas outlet.   
     
     
         15 . A drilling method using the drilling tool according to  claim 3 , the method comprising steps of:
 forming a borehole using the tool main body while supplying the drilling fluid to the tip portion of the tool main body through the supply channel;   discharging the cuttings generated during forming the borehole together with the drilling fluid through the discharge channel into the space between the drilling pipe and the air supply pipe; and   discharging the cuttings and the drilling fluid discharged into the space toward a posterior end side of the tool main body using the compressed air discharged from the exhaust gas outlet.   
     
     
         16 . A drilling method using the drilling tool according to  claim 4 , the method comprising steps of:
 forming a borehole using the tool main body while supplying the drilling fluid to the tip portion of the tool main body through the supply channel;   discharging the cuttings generated during forming the borehole together with the drilling fluid through the discharge channel into the space between the drilling pipe and the air supply pipe; and   discharging the cuttings and the drilling fluid discharged into the space toward a posterior end side of the tool main body using the compressed air discharged from the exhaust gas outlet.   
     
     
         17 . A drilling method using the drilling tool according to  claim 5 , the method comprising steps of:
 forming a borehole using the tool main body while supplying the drilling fluid to the tip portion of the tool main body through the supply channel;   discharging the cuttings generated during forming the borehole together with the drilling fluid through the discharge channel into the space between the drilling pipe and the air supply pipe; and   discharging the cuttings and the drilling fluid discharged into the space toward a posterior end side of the tool main body using the compressed air discharged from the exhaust gas outlet.   
     
     
         18 . A drilling method using the drilling tool according to  claim 7 , the method comprising steps of:
 forming a borehole using the tool main body while supplying the drilling fluid to the tip portion of the tool main body through the supply channel;   discharging the cuttings generated during forming the borehole together with the drilling fluid through the discharge channel into the space between the drilling pipe and the air supply pipe; and   discharging the cuttings and the drilling fluid discharged into the space toward a posterior end side of the tool main body using the compressed air discharged from the exhaust gas outlet.   
     
     
         19 . A drilling method using the drilling tool according to  claim 8 , the method comprising steps of:
 forming a borehole using the tool main body while supplying the drilling fluid to the tip portion of the tool main body through the supply channel;   discharging the cuttings generated during forming the borehole together with the drilling fluid through the discharge channel into the space between the drilling pipe and the air supply pipe; and   discharging the cuttings and the drilling fluid discharged into the space toward a posterior end side of the tool main body using the compressed air discharged from the exhaust gas outlet.   
     
     
         20 . A drilling method using the drilling tool according to  claim 11 , the method comprising steps of:
 forming a borehole using the tool main body while supplying the drilling fluid to the tip portion of the tool main body through the supply channel;   discharging the cuttings generated during forming the borehole together with the drilling fluid through the discharge channel into the space between the drilling pipe and the air supply pipe; and   discharging the cuttings and the drilling fluid discharged into the space toward a posterior end side of the tool main body using the compressed air discharged from the exhaust gas outlet.