JP3877895B2 - Rotating anode X-ray tube - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotating anode X-ray tube rotating anode.
[0002]
[Prior art]
Conventionally, there is a rotary anode X-ray tube as shown in FIG. The rotary anode X-ray tube includes a rotary cylinder 102 to which a rotary anode target 101 is fixed, and a fixed shaft 103 disposed inside the rotary cylinder 102. A first ball bearing 105 and a second ball bearing 106 are arranged between the fixed shaft 103 and the rotating cylinder 102 at a predetermined distance in the axial direction.
[0003]
The inner ring 107 of the first ball bearing 105 is fastened and fixed to the fixed shaft 103, and is axially fixed to a nut 108 screwed into the tip of the fixed shaft 103 and a cylindrical spacer 110 fixed to the fixed shaft 103. It is sandwiched from both sides and fixed in the axial direction. The outer ring 111 of the first ball bearing 105 is sandwiched between the inner circumferential step portion 102A of the rotating cylinder 102 and the cylindrical spacer 112 from both sides in the axial direction, and is fitted and fixed to the inner periphery of the rotating cylinder 102. Yes.
[0004]
Further, the outer ring 113 of the second ball bearing 106 is sandwiched between the cylindrical spacer 112 and another cylindrical spacer 115 from both sides in the axial direction, and is fitted and fixed to the inner periphery of the rotating cylinder 102. On the other hand, the inner ring 116 of the second ball bearing 106 is engaged with the other end of the preload spring 117 whose one end is engaged with the cylindrical spacer 110, and is urged toward the fixed base 118 by the preload spring 117. . Further, the inner ring 116 is fitted so as to be slidable with respect to the fixed shaft 103.
[0005]
In this rotary anode X-ray tube, first and second ball bearings 105 and 106 support a rotary cylinder 102 to which a rotary anode target 101 is fixed, so as to be rotatable with respect to a fixed shaft 103.
[0006]
By the way, in the X-ray tube, the temperature of the rotating anode target 101 changes from a normal temperature of about 20 ° C. to a high temperature of about 400 ° C., and the temperature of the rotating cylinder 102 similarly changes and expands and contracts. Accordingly, the axial distance between the outer ring 111 of the first ball bearing 105 and the outer ring 113 of the second ball bearing 106 expands and contracts. Then, the inner ring 116 of the second ball bearing 106 slides in the axial direction with respect to the fixed shaft 103 while being urged by the preload spring 117 according to the expansion and contraction of the axial distance between the two outer rings 111 and 113. . As a result, the inner ring 116 is made to follow the axial position variation of the outer ring 113 of the second ball bearing 106 due to the thermal expansion and contraction of the rotating cylinder 102, and the ball 120 is brought into the correct path between the outer ring 113 and the inner ring 116. I always try to position it.
[0007]
[Problems to be solved by the invention]
However, in the conventional rotary anode X-ray tube, when the inner ring 116 of the second ball bearing 106 slides with respect to the fixed shaft 103, it may be caught on the outer peripheral surface of the fixed shaft 103 and cannot slide smoothly. In this case, there is a problem that the ball 120 cannot be positioned on the correct track between the outer ring 113 and the inner ring 116, and the bearing function is impaired.
[0008]
Accordingly, an object of the present invention is to smoothly slide the inner ring or the outer ring with respect to the rotating part or the fixed part when the rotating part connected to the rotating anode expands and contracts in the axial direction due to the temperature change of the rotating anode of the X-ray tube. Another object of the present invention is to provide a rotating anode X-ray tube that can always maintain the axial relative position of the outer ring and the inner ring unchanged.
[0009]
[Means for Solving the Problems]
To achieve the above object, the rotating anode X-ray tube of the first aspect of the invention, the axial direction between a rotating portion for supporting the rotating anode target, and a fixed portion disposed coaxially with the rotating part And first and second rolling bearings arranged at a predetermined distance from each other,
A spring disposed between the first rolling bearing and the second rolling bearing and biasing the inner rings or the outer rings of the first and second rolling bearings in the axial direction.
The first, one of the second rolling bearing, one of the inner or outer ring is slidably disposed al is along the axis Direction to either one of the rotating portion or the fixed portion,
The sliding surface of either the inner ring or the outer ring that slides with respect to either the rotating part or the fixed part is coated with a diamond-like carbon thin film for smoothly sliding the sliding surface. The sliding surface is chamfered, and the corner of the chamfer is covered with diamond-like carbon .
[0010]
In the first aspect of the invention, due to thermal expansion (or thermal contraction) due to temperature change of the rotating anode of the X-ray tube, the rotating part connected to the rotating anode expands and contracts in the axial direction, and the axial position of the outer ring or inner ring changes. Sometimes, the diamond-like carbon thin film coated on the inner ring or the outer ring can slide smoothly with respect to the rotating part or the fixed part. Accordingly, the axial relative positions of the outer ring and the inner ring can be always maintained unchanged, and the rolling elements can be always arranged at appropriate positions, and the bearing operation can be stably and reliably maintained.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.
[0012]
Figure 1 shows a form status of implementation of the rotary anode X-ray tube of the present invention. The X-ray tube includes a rotating shaft 2 to which a rotating anode target 1 is fixed, and a fixed cylinder 3 that surrounds the rotating shaft 2. A first ball bearing 5 and a second ball bearing 6 are disposed between the rotating shaft 2 and the fixed cylinder 3 at a predetermined distance in the axial direction.
[0013]
The first ball bearing 5 includes a circumferential groove 7 formed on the outer circumferential surface of the rotating shaft 2, an outer ring 10 that is tightly fitted to the inner circumferential surface 8 of the fixed cylinder 3, and between the outer ring 10 and the circumferential groove 7. And a plurality of balls 11 arranged on the surface. In the outer ring 10 of the first ball bearing 5, one end surface 10 </ b> A in the axial direction is in contact with the inner peripheral step portion 3 </ b> A of the fixed cylinder 3, and the other end surface 10 </ b> B is in contact with one end 16 </ b> A of the spring 16. The other end 16B of the spring 16 biases the spring receiver 17 in the direction of the second ball bearing 6, and the spring receiver 17 biases the outer ring 13 of the second ball bearing 6 in the axial direction.
[0014]
The second ball bearing 6 includes a circumferential groove 12 formed on the outer peripheral surface of the rotary shaft 2, an outer ring 13 slidably fitted to the inner peripheral surface 8 of the fixed cylinder 3, It consists of a plurality of balls 15 arranged between the circumferential grooves 12. The outer ring 13 of the second ball bearing 6 is biased by the spring receiver 17 from one side in the axial direction, and the other end 13B in the axial direction of the outer ring 13 is formed in the circumferential groove 3B formed in the vicinity of the opening end of the fixed cylinder 3. It is opposed to the retaining ring 21 fitted in with a predetermined interval. As shown in FIG. 2, the outer ring 13 is chamfered on the opening side of the fixed cylinder 3, and the outer peripheral surface 13A of the outer ring 13 is tapered toward the opening side. A thin film 20 of diamond-like carbon is coated on the outer peripheral surface 13A of the outer ring 13, that is, the sliding surface 13A. The first and second ball bearings 5 and 6 are lubricated with a solid lubricant.
[0015]
The X-ray tube having the above configuration operates in a vacuum, the rotating anode target 1 is rotated, and the rotating shaft 2 is rotated. The rotary shaft 2 is rotatably supported with respect to the fixed cylinder 3 by the first ball bearing 5 and the second ball bearing 6.
[0016]
By the way, when the X-ray tube operates, the temperature of the rotary anode target 1 rises and the temperature of the rotary shaft 2 rises. As a result, the rotating shaft 2 is thermally expanded, the space between the circumferential grooves 7 and 12 is widened, and the outer ring 13 of the second ball bearing 6 biased by the spring receiver 17 has a retaining ring corresponding to the extension of the rotating shaft 2. It is displaced toward 21. Here, since the outer peripheral surface 13 A of the outer ring 13 of the second ball bearing 6 is coated with a diamond-like carbon thin film 20, the outer ring 13 of the second ball bearing 6 is formed on the inner peripheral surface 8 of the fixed cylinder 3. On the other hand, it can slide smoothly. Therefore, the axial relative position of the outer ring 13 and the circumferential groove 12 can be always maintained unchanged, and the ball 15 can be always disposed at an appropriate position, and the bearing operation can be always stably and reliably maintained. Further, as shown in FIG. 2, the outer peripheral surface 13 </ b> A of the outer ring 13 is chamfered and has a concave shape toward the opening side, and the chamfered corner P is covered with the thin film 20 and is smooth. The outer ring 13 can slide more smoothly with respect to the inner peripheral surface 8.
[0017]
In the embodiment above Symbol embodiment, the cylinder 3 is fixed and is rotating the shaft 2, the rotary anode target 1 is rotated and fixed to the cylindrical 3 may be fixed to the shaft 2. Moreover, in the said embodiment, although the 1st, 2nd ball bearings 5 and 6 did not have an inner ring | wheel, you may eliminate the circumferential grooves 7 and 12 of the rotating shaft 2, and may provide an inner ring | wheel. Furthermore, as in the conventional example (FIG. 3), the outer ring may be fixed to a rotating cylinder, and the inner ring may be slidable with respect to the fixed shaft.
[0018]
【The invention's effect】
As apparent from the above, rotating anode X-ray tube of the first aspect of the invention, expansion and contraction due to thermal expansion caused by temperature changes of the rotary anode X-ray tube (or thermal contraction), the rotating part connected to the rotary anode in the axial direction When the axial position of the outer ring or the inner ring changes, the diamond-like carbon thin film coated on the inner ring or the outer ring can slide smoothly with respect to the rotating part or the fixed part. Accordingly, the axial relative positions of the outer ring and the inner ring can be constantly maintained, the rolling elements can be always disposed at appropriate positions, and the bearing operation can be stably and reliably maintained.
[0019]
[Brief description of the drawings]
1 is a fragmentary cross-sectional view of the form status of implementation of the rotary anode X-ray tube of the present invention.
FIG. 2 is a cross-sectional view of a main part of an outer ring of a second rolling bearing according to the embodiment.
FIG. 3 is a cross-sectional view of a main part of a conventional rotary anode X-ray tube .
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Rotating anode target, 2 ... Rotating shaft, 3 ... Fixed cylinder, 3A ... Inner peripheral step part,
3B ... circumferential groove, 5 ... first ball bearing, 7, 12 ... circumferential groove, 8 ... inner circumferential surface,
10, 13 ... outer ring, 10A, 10B ... end face, 13A ... outer peripheral face (sliding face),
13B ... the other end, 11, 15 ... ball, 20 ... thin film.

Claims (1)

There are first and second rolling bearings arranged at a predetermined distance in the axial direction between a rotating part that supports the rotating anode target and a fixed part that is arranged coaxially with the rotating part. And
A spring disposed between the first rolling bearing and the second rolling bearing and biasing the inner rings or the outer rings of the first and second rolling bearings in the axial direction.
The first, one of the second rolling bearing, one of the inner or outer ring is slidably disposed al is along the axis Direction to either one of the rotating portion or the fixed portion,
The sliding surface of either the inner ring or the outer ring that slides with respect to either the rotating part or the fixed part is coated with a diamond-like carbon thin film for smoothly sliding the sliding surface. A rotating anode X-ray tube characterized in that the sliding surface is chamfered and the corners of the chamfer are covered with diamond-like carbon .

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