X-ray tube and method of manufacturing the same

1. An X-ray tube, comprising:

a cathode comprising:

a filament comprising a coil emitting electrons, and a leg portion extending in an extension direction from the coil to a distal portion and including a corner portion at the distal portion,

a support terminal including a gap sequentially formed from an opening portion to a bottom portion in the extension direction, and

a cathode cup accommodating the filament and the support terminal and being connected to the support terminal,

the leg portion being inserted into the gap from the opening portion,

the distal portion being located in the gap, and

the support terminal comprising a protruding portion protruding in a direction intersecting the extension direction between the distal portion and the bottom portion in the gap, and fixed at the corner portion of the distal portion.

2. The X-ray tube of claim 1 , wherein

the protruding portion is separated from the bottom portion.

3. The X-ray tube of claim 1 , wherein

the protruding portion comprises a first protruding portion and a second protruding portion opposed to the first protruding portion, and

the first protruding portion and the second protruding portion are separated in a distance smaller than a diameter of the leg portion.

4. The X-ray tube of claim 1 , wherein

the protruding portion comprises a first protruding portion and a second protruding portion opposed to the first protruding portion, and

the first protruding portion and the second protruding portion are crimped or joined.

5. The X-ray tube of claim 1 , wherein

the support terminal comprises a first depression formed on an outer first surface, and a second depression formed on a second surface located outside on an opposite side with the first surface and the distal portion sandwiched between the first surface and the second depression.

6. The X-ray tube of claim 5 , wherein

the support terminal comprises a third surface crimped to a first portion of the leg portion located more closely to the coil side than the distal portion in the gap, and a fourth surface opposed to the third surface.

7. The X-ray tube of claim 5 , wherein

the support terminal comprises a third surface joined to a first portion of the leg portion located more closely to the coil side than the distal portion in the gap, and a fourth surface opposed to the third surface.

8. The X-ray tube of claim 6 , wherein

the support terminal comprises a third depression formed on an outer fifth surface, and a fourth depression formed on a sixth surface located outside on an opposite side with the first surface and the distal portion sandwiched between the fifth surface and the fourth depression.

9. The X-ray tube of claim 1 , wherein

the support terminal is formed of, iron, an alloy containing iron as a main component, niobium, an alloy containing niobium as a main component, molybdenum, or an alloy containing molybdenum as a main component.

10. The X-ray tube of claim 1 , wherein

the filament is formed of tungsten or an alloy containing tungsten as a main component.

11. A method of manufacturing an X-ray tube comprising a cathode,

the cathode comprising:

a filament comprising a coil emitting electrons, and a leg portion extending from the coil to a distal portion and including a first corner portion and a second corner portion at the distal portion,

a support terminal including a gap, and comprising an opening portion in which the gap is opened and a bottom portion located an end portion of the gap on a side opposite to the opening portion, and

a cathode cup accommodating the filament and the support terminal and being connected to the support terminal,

the method comprising:

inserting the distal portion of the leg portion into the gap of the support terminal;

supplying a current while applying a pressure to a first surface of the support terminal on an outer side and a second surface of the support terminal located outside on an opposite side with the leg portion sandwiched between the first surface and the second surface, by a pair of electrodes;

urging a third surface of the support terminal in the gap on a side opposite to the first surface to abut on the first corner portion;

joining the third surface to the first corner portion;

urging a fourth surface in the gap of the support terminal opposed to the third surface on a side opposite to the second surface to abut on the second corner portion;

joining the fourth surface to the second corner portion; and

forming a protruding portion located more closely to the bottom portion side than to the distal portion at a position between the distal portion and the bottom portion, in the gap.

12. The method of claim 11 , wherein

a pressure is applied to a fifth surface of the support terminal on an outer side and a sixth surface of the support terminal located outside on an opposite side with a first portion of the leg portion located more closely to the coil side than the distal portion sandwiched between the fifth surface and the sixth surface, by a pair of electrodes,

a seventh surface of the support terminal and an eighth surface opposed to the seventh surface are urged to abut on the first portion, and

the seventh surface and the eighth surface are crimped to the first portion.

13. The method of claim 11 , wherein

a current is supplied while applying a pressure to a fifth surface of the support terminal on an outer side and a sixth surface of the support terminal located outside on an opposite side with a first portion of the leg portion located more closely to the coil side than the distal portion sandwiched between the fifth surface and the sixth surface, by a pair of electrodes,

a seventh surface of the support terminal and an eighth surface opposed to the seventh surface are urged to abut on the first portion, and

the seventh surface and the eighth surface are joined to the first portion.