Trunk injection needle

1. A trunk injection needle, comprising: a front part which is conical, a middle part which is cylindrical, and a rear part which is cylindrical, which are respectively provided along a needle axis; wherein an outer diameter of the rear part is larger than outer diameters of the front part and the middle part; the front part has a bits guiding hole extending along the needle axis, and the rear part has a drug feeding hole extending along the needle axis; wherein the middle part has two outlet holes extending along a radial direction, and a separating board is provided between the two outlet holes; a rear end of the bits guiding hole communicates with the two outlet holes at two sides of the separating board; and a front end of the drug feeding hole communicates with the two outlet holes;

wherein a blade part is provided at a front end of the separating board, which has a cutting edge; from the cutting edge backwards along the needle axis, a radial thickness of the blade part increases.

2. The trunk injection needle, as recited in claim 1 , wherein the cutting edge extends along a needle radial direction; the blade part, the separating board and the two outlet holes are symmetrical according to the cutting edge.

3. The trunk injection needle, as recited in claim 2 , wherein the outer diameter of the middle part, which has the two outlet holes, is smaller than a max outer diameter of the front part.

4. The trunk injection needle, as recited in claim 2 , wherein a cone transition part is provided between the middle part and the rear part.

5. The trunk injection needle, as recited in claim 4 , wherein a cone cutting part is provided at a front end of the front part, an angle between a generating line of the cone cutting part and the needle axis is 25-35 degrees, and a loop blade is formed at an intersection of the cone cutting part and a wall of the bits guiding hole.

6. The trunk injection needle, as recited in claim 5 , wherein an angle between the generating line of the front part being conical and the needle axis is 13-15 degrees; conical degrees of the cone transition part and the front part being conical are identical; and an angle b between two side faces of the blade part is 28-32 degrees.

7. The trunk injection needle, as recited in claim 6 , wherein the two outlet holes are slotted holes, whose widths are equal to a diameter of the bits guiding hole.

8. The trunk injection needle, as recited in claim 2 , wherein a periphery of the rear part has an annular slot for containing an O-ring.

9. The trunk injection needle, as recited in claim 1 , wherein the outer diameter of the middle part, which has the two outlet holes, is smaller than a max outer diameter of the front part.

10. The trunk injection needle, as recited in claim 1 , wherein a cone transition part is provided between the middle part and the rear part.

11. The trunk injection needle, as recited in claim 10 , wherein a cone cutting part is provided at a front end of the front part, an angle between a generating line of the cone cutting part and the needle axis is 25-35 degrees, and a loop blade is formed at an intersection of the cone cutting part and a wall of the bits guiding hole.

12. The trunk injection needle, as recited in claim 11 , wherein an angle between the generating line of the front part being conical and the needle axis is 13-15 degrees; conical degrees of the cone transition part and the front part being conical are identical; and an angle b between two side faces of the blade part is 28-32 degrees.

13. The trunk injection needle, as recited in claim 12 , wherein the two outlet holes are slotted holes, whose widths are equal to a diameter of the bits guiding hole.

14. The trunk injection needle, as recited in claim 1 , wherein a periphery of the rear part has an annular slot for containing an O-ring.