Valve needle and electronic expansion valve having valve needle

1 . A valve needle, wherein the valve needle is provided with a connecting end and a blocking end that are arranged opposite to each other; the blocking end comprises a blocking segment, a first opening segment, and a second opening segment that are sequentially connected in an axial direction; the blocking segment is configured to cooperate with a valve port to block the valve port; a cross sectional area of the blocking segment close to the connecting end is greater than a cross sectional area of the blocking segment distant from the connecting end; a cross sectional area of the second opening segment close to the connecting end is greater than a cross sectional area of the second opening segment distant from the connecting end; the cross sectional area of the blocking segment distant from the connecting end is equal to the cross sectional area of the second opening segment close to the connecting end; and a cross sectional area of the first opening segment remains unchanged; wherein a length of the first opening segment is greater than or equal to 0.1 mm and less than or equal to 0.6 mm, when the first opening segment is located at the valve port, a gap between the first opening segment and the valve port remains unchanged.

2 . The valve needle according to claim 1 , wherein the first opening segment is a cylindrical segment, and the blocking segment is a conical segment.

3 . The valve needle according to claim 1 , wherein the second opening segment comprises a plurality of circulation segments that are sequentially connected in the axial direction, wherein cross sectional areas of at least two circulation segments in the plurality of circulation segments are different, and a cross sectional area of a circulation segment distant from the connecting end is less than a cross sectional area of a circulation segment close to the connecting end.

4 . The valve needle according to claim 3 , wherein cross sectional areas of the plurality of circulation segments gradually decrease in a direction distant from the connecting end.

5 . The valve needle according to claim 3 , wherein the circulation segments are conical segments, and cone angles of the plurality of circulation segments gradually increase in a direction distant from the connecting end.

6 . The valve needle according to claim 1 , wherein a surface roughness of the first opening segment and the second opening segment is less than or equal to 1.6 um.

7 . The valve needle according to claim 1 , wherein a roundness of the first opening segment and the second opening segment is less than or equal to 0.005 mm.

8 . The valve needle according to claim 1 , wherein the blocking end further includes a diversion segment, wherein the diversion segment is arranged on a side of the blocking segment close to the connecting end, the blocking segment is connected with the diversion segment, and a cross sectional area of the diversion segment close to the connecting end is greater than a cross sectional area of the diversion segment distant from the connecting end.

9 . An electronic expansion valve, comprising the valve needle according to claim 1 , wherein the electronic expansion valve is provided with the valve port, the valve needle is movably arranged at the valve port, the electronic expansion valve has a working state and a stopping state, in a case where the electronic expansion valve is in the working state, the second opening segment of the valve needle is located at the valve port, and in a case where the electronic expansion valve is in the stopping state, the blocking segment of the valve needle or the first opening segment is located at the valve port.

10 . The electronic expansion valve according to claim 9 , wherein the gap between the valve port and the first opening segment is greater than or equal to 0.01 mm and less than or equal to 0.06 mm.

11 . The electronic expansion valve according to claim 9 , wherein the first opening segment is a cylindrical segment, and the blocking segment is a conical segment.

12 . The electronic expansion valve according to claim 9 , wherein the second opening segment comprises a plurality of circulation segments that are sequentially connected in the axial direction, wherein cross sectional areas of at least two circulation segments in the plurality of circulation segments are different, and a cross sectional area of a circulation segment distant from the connecting end is less than a cross sectional area of a circulation segment close to the connecting end.

13 . The electronic expansion valve according to claim 12 , wherein cross sectional areas of the plurality of circulation segments gradually decrease in a direction distant from the connecting end.

14 . The electronic expansion valve according to claim 12 , wherein the circulation segments are conical segments, and cone angles of the plurality of circulation segments gradually increase in a direction distant from the connecting end.

15 . The electronic expansion valve according to claim 9 , wherein a surface roughness of the first opening segment and the second opening segment is less than or equal to 1.6 um.

16 . The electronic expansion valve according to claim 9 , wherein a roundness of the first opening segment and the second opening segment is less than or equal to 0.005 mm.

17 . The electronic expansion valve according to claim 9 , wherein the blocking end further includes a diversion segment, wherein the diversion segment is arranged on a side of the blocking segment close to the connecting end, the blocking segment is connected with the diversion segment, and a cross sectional area of the diversion segment close to the connecting end is greater than a cross sectional area of the diversion segment distant from the connecting end.