JPS6063864A - Rotary anode of x-ray tube - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an X-ray tube rotating anode suitable for a large-capacity rotating anode X-ray tube in which the rotating anode rotation shaft has free axial thermal expansion.

[Background of the invention]

As shown in FIG. 1, the rotating anode of a conventional X-ray tube consists of a target 1, a rotor 2, a rotating shaft 3 located inside the anode, and a plurality of rotary anodes fitted between the rotating shaft 3 and a fixed part 4. The rotor 3 is rotatably supported on the fixed part 4 by 5.5" ball bearings. When a rotating anode X-ray tube is used, the rotor 3 functions as an induction motor together with a stator coil (not shown) disposed outside the tube. operate and rotate the rotating part at high speed, for example about 3,000
~1 (rotated at 1,00 Orpm). Also, the target 1 is struck by an electron beam emitted from a cathode (not shown) and accelerated by a high voltage applied between the cathode and anode.
It emits X-rays from there. When an electron beam collides with a target, most of the kinetic energy of the high-speed electrons is converted into thermal energy. The heat is not only radiated as heat rays from the heat-generating portion, but also is transmitted from the Kuget 1 to the rotor 2 and the rotating shaft 3 by thermal conduction, heating these portions to a high temperature. Furthermore, it is also conducted to the fixed part 4 through the bearing 5.5', and is dissipated from the fixed part 4 to the outside of the tube. Due to such usage conditions of the X-ray tube, the fitting part between the rotating shaft 3 and the inner ring of the ball bearing 5.5 degrees, the fixed part 4 and the ball bearing 5 are
．． A temperature difference occurs between the 5° outer ring and the fitting portion. Also, a temperature difference occurs between the ball bearing 5 on the side closer to the target 1 and the ball bearing 5" on the far side. Because of the above temperature difference, the dimensions of each part are adjusted according to the high temperature during use. This must be determined by taking into account the large temperature difference from the room temperature at startup.

As a result, (at high temperatures, the gap inside the ball bearing becomes too large to 1J, causing damage due to large stress, or conversely, at startup, the gap is too large and causes vibration, causing the bearing to become tf1.
Due to the harsh operating conditions peculiar to rotating anode X-ray tubes, such as double rotation, poor rotational life was likely to occur due to damage to the ball bearings. In particular, in large-capacity display tubes in which a large amount of electron flow is injected into the target, the target laser 1- is large and heavy, and the amount of heat generated in the target also increases, so the rotation of the ball bearing due to the above reasons There was a tendency for defective accidents to occur frequently.

In order to reduce the effects of such temperature differences, conventionally, a low-temperature ball bearing 5° far from the heat source is fixed to the axle box 6 of the fitting part of the ball bearing in the fixed part 4, and a high-temperature ball bearing is fixed. 5 also had a structure in which it was slidably attached in the direction of the rotation axis. For large-capacity rotating anode X-ray tubes, even if such a structure is adopted, the rotational life will not be long enough, so
No. 42944 proposes coating the peripheral surface of the outer ring of the ball bearing 5 that comes in contact with the axle box 6 with one of Ag, Au, or Pt metal, but it is still not easy to slide easily. Extending the life of large-capacity rotating anode X-ray tubes has been an extremely difficult problem.

[Purpose of the invention]

The purpose of the J is to lift an X-ray tube rotating anode with easy movement between the outer ring of the ball tlt receiver and the axle box inside the fixing part, where the ball bearing is free from IrJ damage, and which has a long rotation life. Serving item 2: is.

[Summary of the invention]

In order to achieve the above object, in the present invention, at least one outer ring of a plurality of ball bearings supporting the rotating part is supported slidably in the direction of the rotating shaft on an axle box surface inside the fixed part. At least one of the surfaces that slide against each other at this support location is made of a moisturizing material containing a solid lubricant that is resistant to depth and extremely heat-resistant.

[Embodiments of the invention]

FIG. 2 is a diagram showing an embodiment of the present invention. A special Ig is installed at the location where the axle box 6a inside the fixed part 4a supports the outer ring of the ball bearing 5 on the side closer to the cooget so as to be slidable in the direction of the rotation axis.
A supporter 7 that has an easily movable sliding surface and is made of a different material from the other parts of the fixed part is fitted, and the fixed part 4 is held by a holding ring 8.
It is installed on. The supporter 7 is, for example, a porous member made of sintered heat-resistant metal powder. : 6. Impregnated with molybdenum disulfide or tungsten disulfide, which have a proven track record as a vacuum-resistant solid lubricant, or mixed with metal and the solid lubricant 7i 'ft'l and sintered under pressure. Produced with etc. At present, materials such as iron are brittle and have poor airtightness, so it is not possible to make the fixing part 4a from a material that can be bent. Therefore, it is practical to fit and use such a member with good lubricity, that is, the supporter 7, only on the sliding surface where the outer ring of the ball bearing is slidably supported.

When using an X-ray tube, the solid lubricant on the support surface reduces the friction between the support surface and the outer ring of the ball bearing, making it easier for them to slide against each other, and the solid lubricant inside the support Lubricant leaches into the ball bearing contact surface and replenishes it to maintain good sliding performance.

In addition, in Fig. 2, members with the same symbols as in Fig. 1 are shown in Fig. 1.
Same as in the figure.

〔Effect of the invention〕

As explained above, according to the present invention, the ball tdI bearing can easily slide relative to the fixed part. The fluctuation of the gap that was provided to absorb the effects of thermal expansion caused by the temperature difference between the high temperature and the high temperature of the bearing, as well as the problem of bearing rotation failure caused by this, have been resolved, extending the rotation life. Effects such as the ability to manufacture a rotating anode X-ray tube with a larger capacity can be obtained.

[Brief explanation of the drawing]

FIG. 1 shows a rotating anode of a conventional X-ray tube, and FIG. 2 shows an embodiment of the present invention. 1-target, 2--rotor, 3--rotating shaft, 4
．． 4a-Fixed part, 5.5"-・Ball bearing, 6.6a-・
-Axle box, 7-Support, 8-・Press. Figure 1 Figure 2

Claims (1)

[Claims] In an X-ray tube rotating anode in which a rotating part is rotatably supported by a fixed part via a plurality of ball bearings, at least one outer ring of the ball bearing is slidable in the direction of the rotating shaft by the fixed part. At least one of the surfaces that are supported and that slide against each other at the support is made of a lubricating material containing a vacuum, heat-resistant solid lubricant.