JP2000208078A - Rolling bearing for rotating anode x-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolling bearing for a rotating anode X-ray tube, of which the inner ring or outer ring an smoothly slide on a rotating part or a fixed part when the rotating part continued to a rotating anode is axially extended or shrunk by the temperature change of the rotating anode of the X-ray tube, and which can always keep the axial relative position of the outer and inner rings constant. SOLUTION: In this rolling bearing for a rotating anode X-ray tube, a rotating shaft 2 continued to a rotating anode 1 extends and shrinks axially by thermal expansion (or heat contraction) due to the temperature change of the rotating anode 1 of the X-ray tube. When the axial position of a circumferential slot 12 changes, a diamond-like carbon thin film applied to an outside peripheral surface 13A of an outer ring 13 as coating can smoothly slide on an inside peripheral surface 8 of a fixed cylinder 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rolling bearing used for a rotating anode X-ray tube for rotating an anode.

[0002]

2. Description of the Related Art A conventional rotary anode X-ray tube is shown in FIG. The rotating anode X-ray tube includes a rotating cylinder 102 on which a rotating anode target 101 is fixed, and a fixed shaft 103 disposed inside the rotating cylinder 102. A first ball bearing 105 and a second ball bearing 106 are disposed 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 fixedly fitted to the fixed shaft 103 by tight fitting. A nut 108 screwed to the tip of the fixed shaft 103 and a cylindrical spacer 110 fixed to the fixed shaft 103 by tight fitting. And is fixed in the axial direction from both sides in the axial direction. Also, the first ball bearing 105
Outer ring 111 is sandwiched between the inner peripheral step portion 102A of the rotating cylinder 102 and the cylindrical spacer 112 from both sides in the axial direction, and
The rotating cylinder 102 is tightly fitted and fixed to the inner circumference.

The outer ring 113 of the second ball bearing 106
Is a cylindrical spacer 115 different from the cylindrical spacer 112 described above.
And are fixed from both sides in the axial direction to the inner circumference of the rotating cylinder 102 by being tightly fitted. On the other hand, the inner race 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. . The inner ring 116 is fixed to the fixed shaft 103.
Are slidably fitted with respect to.

In this rotary anode X-ray tube, a rotary cylinder 102 on which a rotary anode target 101 is fixed is rotatably supported on a fixed shaft 103 by first and second ball bearings 105 and 106.

Meanwhile, in the X-ray tube, the temperature of the rotating anode target 101 changes from room temperature of about 20 ° C. to a high temperature of about 400 ° C., and the rotating cylinder 102 similarly expands and contracts due to the temperature change. 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, these two outer rings 111 and 1
13 according to the expansion and contraction of the axial distance from the second ball bearing 106.
The inner ring 116 slides in the axial direction with respect to the fixed shaft 103 while being urged by the preload spring 117. Thus, the inner ring 116 follows the axial position fluctuation of the outer ring 113 of the second ball bearing 106 caused by the thermal expansion and thermal contraction of the rotating cylinder 102, and the ball 120 is moved to the outer ring 113 and the inner ring 11.
It is always on the right track between the six.

[0007]

However, in the above-mentioned 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, the inner ring 116 is caught on the outer peripheral surface of the fixed shaft 103. May not slide smoothly. In this case, the ball 120 is connected to the outer ring 113 and the inner ring 116.
Cannot be positioned on the correct track between the bearings, and the bearing function is impaired.

Accordingly, an object of the present invention is to provide an inner ring or an outer ring which is smooth with respect to a rotating part or a fixed part when a rotating part connected to the rotating anode expands and contracts in the axial direction due to a temperature change of the rotating anode of the X-ray tube. It is an object of the present invention to provide a rotating anode X-ray tube rolling bearing that can slide in the axial direction and always maintain the relative position of the outer race and the inner race in the axial direction unchanged.

[0009]

In order to achieve the above object, a rolling bearing for a rotary anode X-ray tube according to the invention of claim 1 is provided.
A rotating portion that supports the rotating anode target and a fixed portion provided coaxially with respect to the rotating portion are provided between the rotating portion and the fixed portion. In a rolling anode X-ray tube rolling bearing slidably provided along a bearing direction, a sliding surface of either the inner ring or the outer ring sliding on either the rotating part or the fixed part is provided. , Characterized by being coated with a diamond-like carbon thin film.

According to the first aspect of the present invention, the rotating portion connected to the rotating anode expands and contracts in the axial direction due to thermal expansion (or thermal contraction) due to a temperature change of the rotating anode of the X-ray tube, and the axial position of the outer ring or the inner ring is changed. Is changed, the thin film of diamond-like carbon coated on the inner ring or the outer ring can slide smoothly on the rotating part or the fixed part. Therefore, the relative position of the outer ring and the inner ring in the axial direction can always be maintained unchanged, the rolling elements can always be arranged at appropriate positions, and the bearing operation can be stably and reliably maintained.

A rolling bearing for a rotary anode X-ray tube according to a second aspect of the present invention is provided between a rotary portion supporting a rotary anode target and a fixed portion disposed coaxially with the rotary portion. In a rolling bearing for a rotating anode X-ray tube in which one of an inner ring and an outer ring is slidably provided in one of the rotating portion and the fixed portion along a bearing direction, any one of the rotating portion and the fixed portion is provided. On the sliding surface of either the inner ring or the outer ring that slides on one side,
It is characterized by being coated with a thin film of lead.

According to the second aspect of the invention, the lead thin film coated on the inner ring or the outer ring can slide smoothly on the rotating portion or the fixed portion. Therefore, the relative position of the outer ring and the inner ring in the axial direction can always be maintained unchanged, the rolling elements can always be arranged at appropriate positions, and the bearing operation can be stably and reliably maintained.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

FIG. 1 shows a rotary anode X-ray tube provided with an embodiment of a rolling bearing for a rotary anode X-ray tube according to the present invention. The X-ray tube includes a rotating shaft 2 on which a rotating anode target 1 is fixed, and a fixed cylinder 3 surrounding the outside of the rotating shaft 2. A first ball bearing 5 and a second ball bearing 6 are arranged between the rotating shaft 2 and the fixed cylinder 3 at a predetermined distance in the axial direction.

The first ball bearing 5 includes a peripheral groove 7 formed on the outer peripheral surface of the rotating shaft 2, an outer ring 10 tightly fitted on an inner peripheral surface 8 of the fixed cylinder 3, and the outer ring 10 and the peripheral groove. 7 and a plurality of balls 11 arranged between them. The outer ring 10 of the first ball bearing 5 has one end face 10A in the axial direction abutting on the inner peripheral step 3A of the fixed cylinder 3, and the other end face 10B abutting on one end 16A of the spring 16. The other end 16 </ b> B of the spring 16 connects the spring receiver 17 to the second ball bearing 6.
, And the spring receiver 17 urges the outer ring 13 of the second ball bearing 6 in the axial direction.

The second ball bearing 6 includes a peripheral groove 12 formed on the outer peripheral surface of the rotating shaft 2, an outer ring 13 slidably and loosely fitted on the inner peripheral surface 8 of the fixed cylinder 3, It comprises a plurality of balls 15 arranged between the outer race 13 and the circumferential groove 12. The outer race 13 of the second ball bearing 6 is urged by the spring receiver 17 from one side in the axial direction, and the other end 1 in the axial direction of the outer race 13 is
3B is a peripheral groove 3B formed near the open end of the fixed cylinder 3.
And is opposed to the retaining ring 21 fitted at a predetermined interval.
Further, as shown in FIG.
Of the outer ring 13 is chamfered on the opening side of the outer ring 13.
Is tapered toward the opening side. The outer peripheral surface 13A of the outer ring 13, that is, the sliding surface 13A is coated with a diamond-like carbon thin film 20. The first and second ball bearings 5, 6 are lubricated with a solid lubricant.

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 rotating shaft 2 is rotatably supported on the fixed cylinder 3 by the first ball bearing 5 and the second ball bearing 6.

When the X-ray tube operates, the temperature of the rotating anode target 1 rises, and the temperature of the rotating shaft 2 rises. As a result, the rotating shaft 2 thermally expands and the circumferential grooves 7 and 1
2, the outer ring 13 of the second ball bearing 6 urged by the spring receiver 17 is displaced toward the retaining ring 21 by the length of the rotation shaft 2. Here, the outer peripheral surface 13A of the outer ring 13 of the second ball bearing 6 is coated with the diamond-like carbon thin film 20.
The outer ring 13 of the second ball bearing 6 can slide smoothly with respect to the inner peripheral surface 8 of the fixed cylinder 3. Therefore, the relative position of the outer race 13 and the circumferential groove 12 in the axial direction can always be maintained unchanged, the ball 15 can be always arranged at an appropriate position, and the bearing operation can always be stably and surely maintained. Also, as shown in FIG.
Since the outer peripheral surface 13A of the outer ring 13 is chamfered and is tapered toward the opening side, and the chamfered angle P is covered with the thin film 20 to be smooth, the outer ring 13 is In contrast, you can slide more smoothly.

In the above embodiment, the coating thin film 20 is a diamond-like carbon thin film, but may be a lead thin film. Further, in the above-described embodiment, the cylinder 3 is fixed and the shaft 2 is rotated. However, the rotating anode target 1 may be fixed to the cylinder 3 and rotated to fix the shaft 2.
Further, in the above-described embodiment, the first and second ball bearings 5 and 6 do not have the inner rings. However, the inner grooves may be provided without the circumferential grooves 7 and 12 of the rotating shaft 2. Further, 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 a fixed shaft.

[0020]

As is apparent from the above description, the rolling bearing for a rotating anode X-ray tube according to the first aspect of the present invention is connected to the rotating anode by thermal expansion (or thermal contraction) due to a temperature change of the rotating anode of the X-ray tube. When the rotating part expands and contracts in the axial direction and the axial position of the outer ring or inner ring changes, a thin film of diamond-like carbon coated on the inner ring or outer ring
It can slide smoothly on the rotating part or the fixed part. Therefore, the relative position of the outer ring and the inner ring in the axial direction can always be maintained unchanged, the rolling elements can always be arranged at appropriate positions, and the bearing operation can be stably and reliably maintained.

Further, in the rolling bearing for a rotary anode X-ray tube according to the second aspect of the present invention, the lead thin film coated on the inner ring or the outer ring can smoothly slide on the rotating part or the fixed part. Therefore, the relative position of the outer ring and the inner ring in the axial direction can always be maintained unchanged, the rolling elements can always be arranged at appropriate positions, and the bearing operation can be stably and reliably maintained.

[Brief description of the drawings]

FIG. 1 is a sectional view of an essential part of an X-ray tube provided with a rolling anode X-ray tube rolling bearing according to an embodiment of the present invention.

FIG. 2 is a sectional view of a main part of an outer race of a second rolling bearing according to the embodiment.

FIG. 3 is a sectional view of a main part of an X-ray tube provided with a conventional rolling bearing for a rotary anode X-ray tube.

[Explanation of symbols]

1 ... rotating anode target, 2 ... rotating shaft, 3 ... fixed cylinder,
3A: inner peripheral step, 3B: peripheral groove, 5: first ball bearing, 7.1
2 ... peripheral groove, 8 ... inner peripheral surface, 10, 13 ... outer ring, 10A, 10
B: end surface, 13A: outer peripheral surface (sliding surface), 13B: other end, 1
1,15: ball, 20: thin film.

Claims (2)

[Claims] 1. A rotating part for supporting a rotating anode target, and a fixed part disposed coaxially with the rotating part, wherein one of an inner ring and an outer ring is provided on the rotating part or the fixed part. A rotating anode X-ray tube rolling bearing provided slidably along one of the bearings in the bearing direction, wherein either the inner ring or the outer ring slides against either the rotating part or the fixed part. A rolling bearing for a rotary anode X-ray tube, characterized in that the sliding surface of (1) is coated with a diamond-like carbon thin film. 2. A rotary unit for supporting a rotary anode target, and a fixed unit disposed coaxially with the rotary unit, and one of an inner ring and an outer ring is provided between the rotary unit and the fixed unit. A rotating anode X-ray tube rolling bearing provided slidably along one of the bearings in the bearing direction, wherein either the inner ring or the outer ring slides against either the rotating part or the fixed part. A rolling bearing for a rotating anode X-ray tube, characterized in that the sliding surface of (1) is coated with a thin film of lead.