1. A gun drill comprising:
a tool shank;
a cutting head mounted on a distal end portion of the tool shank, the cutting head having a longitudinally extending head central axis (O) around which the cutting head rotates;
a coolant supply passage provided inside the tool shank and a coolant supply passage provided inside the cutting head, the two coolant supply passages communicating with one another;
a coolant discharge port opened at the cutting head and communicating with the coolant supply passage provided inside the cutting head;
a cutting chip discharge groove provided on an outer circumferential surface and extending lengthwise from a proximal side of the tool shank to a cutting head distal end; and
a cutting blade provided at the cutting head distal end and bordering the cutting chip discharge groove, wherein the cutting blade comprises:
a blade edge having an inner end spaced apart from the head central axis of the cutting head, whereby the inner end forms a non-cutting zone in the vicinity of the head central axis upon rotation of the gun drill during drilling operations, and
a cutting blade side face at an inner end side of the cutting blade, the cutting blade side face having an inclined surface which is inclined from the inner end to the head central axis side,
wherein the inclined surface of the cutting blade side face is configured to press-contact and break off an uncut core generated in the non-cutting zone upon rotation of the gun drill during drilling operations.
2. The gun drill according to claim 1, wherein:
the cutting blade side face forms an angle of 75 to 90 degrees with respect to a cutting blade front face.
3. The gun drill according to claim 1, wherein:
the inner end of the blade edge is spaced 0.05 to 0.5 mm apart from the head central axis; and
an inclination angle of the cutting blade side face with respect to the head central axis is 5 to 30 degrees.
4. The gun drill according to claim 1, wherein the blade edge of the cutting blade is arranged parallel to radial line (R) passing through the head central axis, and in a center-raised position 0.2 to 1.5 mm more forward in a cutting rotation direction than the radial line.
5. The gun drill according to claim 1, wherein:
the cutting blade comprises a cutting blade tip brazed to a recessed portion of the cutting head.
6. The gun drill according to claim 1, wherein:
a guide pad is provided on an outer circumferential surface of the cutting head at a position opposite to the cutting blade; and
an entire blade edge of the cutting blade is steeply and forwardly inclined toward the head central axis side.
7. The gun drill according to claim 1, wherein:
an entire blade edge of the cutting blade is forwardly inclined toward the head central axis side.
8. The gun drill according to claim 1, wherein:
the inner end constitutes the forwardmost portion of the cutting head.
9. The gun drill according to claim 1, wherein:
the head central axis intersects the inclined surface of the cutting blade side face.
10. The gun drill according to claim 1, wherein:
the cutting blade is a single-edged blade.
11. The gun drill according to claim 1, wherein:
an entire blade edge of the cutting blade is forwardly inclined toward the head central axis side;
the inner end constitutes the forwardmost portion of the cutting head;
the head central axis intersects the inclined surface of the cutting blade side face; and
the cutting blade is a single-edged blade.
12. The gun drill according to claim 11, wherein:
a guide pad is brazed onto an outer circumferential surface of the cutting head at a position opposite to the cutting blade; and
the cutting blade comprises a cutting blade tip brazed to a recessed portion of the cutting head; and
the cutting blade tip and the guide pad are devoid of clamping bores suitable for receiving a clamping screw.
13. A method for cutting a workpiece, comprising:
providing a gun drill comprising:
a tool shank;
a cutting head mounted on a distal end portion of the tool shank, the cutting head having a longitudinally extending head central axis (O) around which the cutting head rotates;
a coolant supply passage provided inside the tool shank and a coolant supply passage provided inside the cutting head, the two coolant supply passages communicating with one another;
a coolant discharge port opened at the cutting head and communicating with the coolant supply passage provided inside the cutting head;
a cutting chip discharge groove provided on an outer circumferential surface and extending lengthwise from a proximal side of the tool shank to a cutting head distal end; and
a cutting blade provided at the cutting head distal end and bordering the cutting chip discharge groove, wherein the cutting blade comprises:
a blade edge having an inner end spaced apart from the head central axis of the cutting head, whereby the inner end forms a non-cutting zone in the vicinity of the head central axis upon rotation of the gun drill during drilling operations, and
a cutting blade side face at an inner end side of the cutting blade, the cutting blade side face having an inclined surface which is inclined from the inner end to the head central axis side, and
drilling the workpiece to thereby form a hole having an uncut core in the non-cutting zone;
wherein the inclined surface of the cutting blade side face press-contacts and breaks off the uncut core upon rotation of the gun drill during drilling operations.
14. The method according to claim 13, comprising fragmenting the uncut core little by little.
15. The method according to claim 13, wherein the blade edge does not contact the uncut core, during drilling operations.
16. A gun drill comprising:
a tool shank;
a cutting head mounted on a distal end portion of the tool shank, the cutting head having a longitudinally extending head central axis (O) around which the cutting head rotates;
a coolant supply passage provided inside the tool shank and a coolant supply passage provided inside the cutting head, the two coolant supply passages communicating with one another;
a coolant discharge port opened at the cutting head and communicating with the coolant supply passage provided inside the cutting head;
a cutting chip discharge groove provided on an outer circumferential surface and extending lengthwise from a proximal side of the tool shank to a cutting head distal end; and
a cutting blade provided at the cutting head distal end and bordering the cutting chip discharge groove, wherein the cutting blade comprises:
a single blade edge having an inner end spaced apart from the head central axis of the cutting head, and
a cutting blade side face at an inner end side of the cutting blade, the cutting blade side face having an inclined surface which is inclined from the inner end to the head central axis side,
and wherein:
an entire blade edge of the cutting blade is forwardly inclined toward the head central axis;
the inner end constitutes the forwardmost portion of the cutting head; and
the head central axis intersects the inclined surface of the cutting blade side face.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method of controlling injection in an internal combustion engine (1), comprising the step of:
determining a nominal fuel quantity (QLOAD) for injection into said engine (1) as a function of user requirements;
characterized by also comprising the steps of:
estimating the fuel quantity (QEST) actually injected into said engine (1) as a function of intake air flow (AIRMEAS) and exhaust ratio (\u03bbUEGO);
controlling fuel injection into said engine (1) so that the estimated fuel quantity (QEST) substantially equals said nominal fuel quantity (QLOAD).
2. A method as claimed in claim 1, characterized in that said step of controlling fuel injection into said engine comprises the steps of:
generating a self-adapting map (29) storing a number of self-adapting correction factors (ACF), each related to a respective operating point of the engine as defined by speed and load;
correcting said nominal fuel quantity (QLOAD), at a given operating point of the engine, as a function of the self-adapting correction factor (ACF) related to said operating point of the engine; and
injecting the corrected fuel quantity (QCOR) into said engine (1).
3. A method as claimed in claim 2, characterized in that said step of correcting said nominal fuel quantity (QLOAD) comprises the step of:
making a proportional correction of said nominal fuel quantity (QLOAD) as a function of said self-adapting correction factor (ACF).
4. A method as claimed in claim 3, characterized in that said step of making a proportional correction comprises the step of:
multiplying said nominal fuel quantity (QLOAD) by said self-adapting correction factor (ACF).
5. A method as claimed in claim 1, characterized in that said step of controlling fuel injection into said engine also comprises the steps of:
determining a compensating correction factor (CCF) as a function of the difference between said estimated fuel quantity (QEST) and said nominal fuel quantity (QLOAD); and
correcting said nominal fuel quantity (QLOAD) as a function of said compensating correction factor (CCF).
6. A method as claimed in claim 5, characterized in that said step of determining a compensating correction factor (CCF) comprises the steps of:
determining an injection error (ERR) related to the difference between said estimated fuel quantity (QEST) and said nominal fuel quantity (QLOAD); and
determining said compensating correction factor (CCF) as a function of the integral of said injection error (ERR).
7. A method as claimed in claim 5, characterized in that said step of correcting said nominal fuel quantity (QLOAD) as a function of said compensating correction factor (CCF) comprises the step of:
multiplying said nominal fuel quantity (QLOAD) by said self-adapting correction factor (ACF) and said compensating correction factor (CCF).
8. A method as claimed in claim 5, characterized by also comprising the step of:
updating said self-adapting map (29) as a function of said compensating correction factor (CCF).
9. A method as claimed in claim 8, characterized in that said step of updating said self-adapting map comprises, for a given operating point of the engine, the step of:
replacing the self-adapting correction factor (ACF) relative to said operating point of the engine with the product of the self-adapting correction factor (ACF) itself and the compensating correction factor (CCF) 20 calculated for the same operating point of the engine.
10. A method as claimed in claim 1, characterized by also comprising the step of:
controlling the exhaust gas quantity recirculated into said engine (1), so that the intake air flow (AIRMEAS) substantially equals a reference air flow (AIRREF) calculated as a function of said nominal fuel quantity (QLOAD) and a reference ratio (\u03bbREF).
11. A method as claimed in claim 1, wherein said internal combustion engine is a diesel engine.
12. A device for controlling injection in an internal combustion engine (1), and comprising:
first calculating means (16) for determining a nominal fuel quantity (QLOAD) for injection into said engine (1) as a function of user requirements;
characterized by also comprising:
estimating means (28) for estimating the fuel quantity (QEST) actually injected into said engine (1) as a function of intake air flow (AIRMEAS) and exhaust ratio (\u03bbUEGO); and
first control means (20) for controlling fuel injection into said engine (1) so that the estimated fuel quantity (QEST) substantially equals said nominal fuel quantity (QLOAD).
13. A device as claimed in claim 12, characterized 15 in that said first control means (20) comprise:
a self-adapting map (29) storing a number of\u02dcself-adapting correction factors (ACF), each related to a respective operating point of the engine as defined by speed and load;
first correcting means (23, 24) for correcting said nominal fuel quantity (QLOAD), at a given operating point of the engine, as a function of the self-adapting correction factor (ACF) related to said operating point of the engine; and
first injecting means f8) for injecting the corrected fuel quantity (QCOR) into said engine (1).
14. A device as claimed in claim 13, characterized in that said first correcting means (23, 24) make a proportional correction of said nominal fuel quantity (QLOAD) as a function of said self-adapting correction factor (ACF).
15. A device as claimed in claim 14, characterized 5 in that said first correcting means comprise first multiplication means (23, 24) for multiplying said nominal fuel quantity (QLOAD) by said self-adapting correction factor (ACF).
16. A device as claimed in claim 12, characterized 10 in that said first control means (20) also comprise:
second calculating means (21, 22) for calculating a compensating correction factor (CCF) as a function of the difference between said estimated fuel quantity (QEST) and said nominal fuel quantity (QLOAD); and
second correcting means (23, 24) for correcting said nominal fuel quantity (QLOAD) as a function of said compensating correction factor (CCF).
17. A device as claimed in claim 16, characterized in that said second calculating means (21, 22) comprise:
third calculating means (21) for calculating an injection error (ERR) related to the difference between said estimated fuel quantity (QEST) and said nominal fuel quantity (QLOAD); and
fourth calculating means (22) for calculating said 25 compensating correction factor (CCF) as a function of the integral of said injection error (ERR).
18. A device as claimed in claim 16, characterized in that said second correcting means (23, 24) comprise:
second means (23, 24) for fuel quantity (QLOAD) by said correction factor (ACF) and said compensating correction factor (CCF).
19. A device as claimed in claim 16, characterized by also comprising:
updating means (29, 30) for updating said self-adapting map (29) function of said compensating correction factor (CCF).
20. A device as claimed in claim 19, characterized in that, for a given operating point of the engine, said means (29, 30) replace the self-adapting correction factor (ACF) relative to said operating point of the engine with the product of the self-adapting correction factor (ACF) itself and the compensating correction factor (CCF) calculated for the same operating point of the engine.
21. A device as claimed in claim 12, characterized by also comprising:
second control means (19) controlling the exhaust gas quantity recirculated into said engine (1), so that the intake air flow (AIRMEAS) substantially equals a reference air flow (AIRREF) calculated as a function of said nominal fuel quantity (QLOAD) and a stoichiometric lambda (\u03bbREF).
22. A device as claimed in claim 12, wherein the internal combustion engine is a diesel engine.