Rotary-positive-electrode-type x-ray tube device

Abstract

The present invention comprises a negative electrode 21 that emits electrons, a rotary positive electrode 23 that generates X-rays due to the electrons emitted from the negative electrode 21, a housing 29 that holds an outer ring 27C of a rotary bearing 27, a preload spring 35 that applies a preload to the outer ring 27C, and a sliding member 39 that is disposed between the outer ring 27C and the preload spring 35 and slides along the inner peripheral surface of the housing 29. The sliding member 39 is provided with a first sliding portion 51 that can slide along the inner peripheral surface of the housing 29, a second sliding portion 53 that is disposed at a prescribed distance from the first sliding portion 51 and can slide along the inner peripheral surface of the housing 29, and a groove portion 55 that is formed between the first sliding portion 51 and the second sliding portion 53.

Description

Rotating anode X-ray tube device

[0001] The present invention relates to a rotating anode X-ray tube assembly.

[0002] In X-ray imaging performed in the medical field and the like, an X-ray imaging apparatus equipped with a rotating anode X-ray tube device is used as an X-ray tube device that irradiates X-rays onto a subject (see, for example, Patent Document 1). The X-ray tube that constitutes the rotating anode X-ray tube device includes a cathode that emits electrons and a rotating anode that is controlled to rotate at a specified rotation speed.

[0003] Electrons emitted from the cathode are accelerated by the tube voltage and collide with a rotating anode, which is driven to rotate. When the electrons collide with the rotating anode, X-rays are generated along with heat. In a rotating anode X-ray tube assembly, electrons are incident on a rotating anode, so the part of the anode where heat is generated is constantly moving. This increases the actual area of ​​the anode on which the electrons collide. Therefore, in a rotating anode X-ray tube assembly, the allowable amount of heat that can be accumulated in the anode is greater than in a fixed anode X-ray tube assembly, and electrons can be incident on the anode with a greater output.

[0004] In the rotating anode X-ray tube assembly disclosed in Patent Document 1, a rotating shaft fastened to a rotating anode is rotatably supported by a ball bearing. The ball bearing includes a ball and an outer ring and an inner ring that sandwich the ball. A preload spring applies a preload to the outer ring of the ball bearing in the axial direction of the rotating shaft. Applying a preload to the outer ring of the ball bearing stabilizes the trajectory along which the ball rolls inside the ball bearing. Stabilizing the trajectory of the ball reduces noise, vibration, and the like generated by the rotating anode.

[0005] The ball bearing is inscribed in a housing that contains the rotating anode. The preload applied by the preload spring is transmitted to the ball bearing via a sliding member, for example, a pipe-like member. The sliding member is structured to fit into the housing and slides along the inner surface of the housing in the axial direction of the rotating shaft.

[0006] X-ray tube devices are generally used in quiet environments such as hospitals, and smooth communication between medical staff and patients is essential. For this reason, it is desirable for the noise generated during operation of a rotating anode X-ray tube device to be as low as possible.

[0007] JP 2023-3899 A

[0008] However, the conventional example having such a configuration has the following problem: In the conventional device, it is difficult to sufficiently reduce the noise and vibration generated in the rotating anode X-ray tube assembly.

[0009] When a solid metal lubricant is used as the lubricant in conventional devices, the sliding of the sliding member causes metal-to-metal contact between the outer circumferential surface of the sliding member and the inner circumferential surface of the housing, which is likely to cause scratches and metal adhesion at the contact surface between the outer circumferential surface of the sliding member and the inner circumferential surface of the housing due to friction between the sliding member and the housing when the rotating anode rotates.

[0010] Scratches and metal adhesion on the contact surface between the sliding member and the housing reduce the sliding function of the sliding member. As a result, the preload from the preload spring is not transmitted sufficiently to the ball bearing, causing the trajectory along which the balls roll inside the ball bearing to become unstable. When the trajectory of the balls becomes unstable, the balls collide with the inner ring or outer ring, raising concerns about increased noise and vibration in the rotating anode X-ray tube assembly.

[0011] Furthermore, if the rolling track of the balls becomes unstable, the solid lubricant film will be formed on areas other than the designated raceway, preventing normal formation of the lubricant film. As a result, abnormal wear of the solid lubricant or deterioration of the sliding members will occur, which may shorten the life of the rotating anode X-ray tube assembly.

[0012] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a rotating anode X-ray tube assembly that can further reduce noise and vibration and enable use for a longer period of time.

[0013] In order to achieve the above object, the present invention has the following configuration: That is, one aspect of the present invention includes a cathode that emits electrons, a rotary anode that generates X-rays by the electrons emitted from the cathode, a rotary drive unit that supports and rotates the rotary anode, a rotary bearing that is arranged in the circumferential direction of the rotary drive unit and has an outer ring and an inner ring that sandwich a rolling element, a holder that holds the outer ring, a preload applying unit that applies a preload to the outer ring in the direction of the rotation axis of the rotary anode, and a bearing that is arranged between the outer ring and the preload applying unit and slides in the direction of the rotation axis along the inner peripheral surface of the holder. and an envelope that contains the cathode, the rotary anode, the rotary drive unit, the rotary bearing, the holding unit, the preload applying unit, and the sliding member in a vacuum atmosphere, wherein the sliding member includes a first sliding part that is slidable along the inner circumferential surface of the holding unit, a second sliding part that is disposed at a predetermined distance from the first sliding part and is slidable along the inner circumferential surface of the holding unit, and a groove part that is formed between the first sliding part and the second sliding part.

[0014] A rotary anode X-ray tube assembly according to an aspect of the present invention includes a sliding member disposed between the outer ring of the rotary bearing and the preload applying portion. The sliding member slides in the direction of the rotation axis of the rotary anode along the inner circumferential surface of the holding portion that holds the outer ring of the rotary bearing. The sliding member includes a first sliding portion and a second sliding portion that are slidable along the inner circumferential surface of the holding portion. The second sliding portion is disposed at a predetermined distance from the first sliding portion.

[0015] A groove is formed between the first sliding portion and the second sliding portion. In other words, the contact area between the inner surface of the holder and the sliding member is reduced by the area of ​​the groove. This reduces the occurrence of scratches and metal adhesion due to friction between the sliding member and the holder. As a result, the preload is efficiently transmitted from the preload applying portion to the rotary bearing via the sliding member, further stabilizing the rolling trajectory of the rolling portion of the rotary bearing. This prevents noise and vibration from occurring in the rotary anode X-ray tube assembly. Furthermore, abnormal wear of the solid lubricant and deterioration of the sliding member can be prevented, thereby extending the life of the rotary anode X-ray tube assembly.

[0016] Furthermore, the sliding member contacts the inner surface of the holding portion at each of the first sliding portion and the second sliding portion, which are separated by the groove. That is, the sliding member contacts the inner surface of the holding portion at two or more regions, which are separated from each other. As a result, the stability of the sliding member can be improved.

[0017] 1 is a longitudinal sectional view illustrating the overall configuration of a rotating anode X-ray tube assembly according to the first embodiment; FIG. 2 is a longitudinal sectional view illustrating the configuration of an X-ray tube according to the first embodiment; FIG. 3 is a longitudinal sectional view illustrating a main part of an X-ray tube according to the first embodiment; FIG. 4 is a longitudinal sectional view of a sliding member according to the first embodiment; FIG. 5 is a perspective view of a sliding member according to the first embodiment; FIG. 6 is a longitudinal sectional view illustrating a portion where the sliding member according to the first embodiment abuts against a housing; FIG. 7 is a longitudinal sectional view of a sliding member according to a conventional embodiment; FIG. 8 is a longitudinal sectional view illustrating a portion where the sliding member according to the conventional embodiment abuts against a housing; FIG. 9 is a diagram illustrating a problem with the sliding member according to the conventional embodiment; (a) is a diagram illustrating a state where scratches and metal adhesion have occurred, and (b) is a diagram illustrating a state where the scratches and metal adhesion expand; (b) is a perspective view illustrating a range where scratches and metal adhesion have occurred in the sliding member according to the conventional embodiment; (a) is a diagram illustrating a state where scratches and metal adhesion have occurred, and (b) is a diagram illustrating a state where the expansion of the scratches and metal adhesion is suppressed; (b) is a perspective view illustrating a range where scratches and metal adhesion have occurred in the sliding member according to the first embodiment; Fig. 10 is a perspective view illustrating the configuration of a sliding member according to a second embodiment; Fig. 11 is a longitudinal sectional view illustrating a portion where the sliding member according to the second embodiment abuts against a housing; Fig. 12 is a perspective view of a sliding member according to a modified embodiment; Fig. 13 is a longitudinal sectional view illustrating a main portion of an X-ray tube according to a modified embodiment; First embodiment

[0018] A rotating anode X-ray tube assembly 1 according to a first embodiment of the present invention will now be described with reference to the drawings.

[0019] <Explanation of Overall Configuration> As shown in FIG. 1 , the rotating anode X-ray tube assembly 1 according to the first embodiment includes a tube container 3, an X-ray tube 5, a stator 7, a bolt 9, an anode holder 11, a cathode holder 13, a cable receptacle 15, a conductor 16, and a rotational speed detector 17.

[0020] The X-ray tube 5 is housed inside the tube vessel 3, and insulating oil is filled between the tube vessel 3 and the X-ray tube 5. The stator 7 is disposed on the outer periphery of the X-ray tube 5. The specific location of the stator 7 corresponds to the outer periphery of a rotor 25, which will be described later. The stator 7 generates a magnetic field when power is applied from the outside, and this magnetic field rotates the rotor 25, which will be described later. The stator 7 is fixed to the tube vessel 3 with bolts 9.

[0021] The X-ray tube 5 is fixed to the tube housing 3 by an anode holder 11 and a cathode holder 13. Cable receptacles 15 are provided on both ends inside the tube housing 3. The cable receptacles 15 supply power via conductors 17 to a cathode 21 and a rotating anode 23, which will be described later.

[0022] Next, the configuration of the X-ray tube 5 will be described with reference to Fig. 2. The X-ray tube 5 includes an envelope 19, a cathode 21, a rotating anode 23, a rotating cylindrical portion 25, a rotary bearing 27, a rotary bearing 28, a housing 29, and a rotating portion 31.

[0023] The envelope 19 is made of glass, for example, and is configured to have a vacuum inside. That is, the envelope 19 contains a cathode 21, a rotary anode 23, a rotating part 31, a rotary bearing 27, a housing 29, a preload spring 35, and a sliding member 39, which will be described later, in a vacuum atmosphere.

[0024] The cathode 21 is composed of a focusing electrode 21a and a filament 21b connected to the conductor 17. The filament 21b has a coil-like configuration made of tungsten, for example, and emits electrons. The rotating anode 23 is disposed opposite the cathode 21. The rotating anode 23 generates X-rays from the electrons emitted from the cathode 21.

[0025] The rotating cylindrical portion 25 has a shape with a bottom surface at one end of the cylinder. A rotary bearing 27, a rotary bearing 28, a housing 29, and a rotating portion 31 are arranged inside the rotating cylindrical portion 25. The rotating cylindrical portion 25 is connected to the rotary anode 23. The rotating cylindrical portion 25 rotates around the rotation axis P due to the magnetic field generated by the stator 7. In other words, the rotating anode 23 is configured to rotate in conjunction with the rotation of the rotating cylindrical portion 25. In each of the drawings, the direction in which the rotation axis P extends is defined as the x-direction.

[0026] The rotary bearings 27 and 28 are disposed inside the housing 29. The rotary bearings 27 and 28 are fitted onto the outer periphery of the rotating part 31. The rotary bearings 27 and 28 support the rotating part 31 rotatably relative to the housing 29. The rotary bearings 27 and 28 are disposed at a predetermined distance in the direction of the rotation axis P. Of the rotary bearings 27 and 28, the rotary bearing 28 is disposed closer to the rotary anode 23. In Figure 2, a detailed description of the structures of the rotary bearings 27 and 28 is omitted.

[0027] The rotating part 31 has a cylindrical shape extending in the x direction as a whole. The rotating part 31 is disposed inside the housing 29. The rotating part 31 is connected to the rotating cylindrical part 25. That is, the rotating part 31 supports the rotary anode 23 via the rotating cylindrical part 25. The rotating part 31 rotates together with the rotary anode 23 in conjunction with the rotation of the rotating cylindrical part 25. That is, each of the rotating cylindrical part 25, the rotating part 31, and the rotary anode 23 rotates around the rotation axis P.

[0028] The detailed structure of the rotary bearing 27 and the rotary bearing 28 will be described using Figure 3. The rotary bearing 27 includes rolling elements 27A, an inner ring 27B, and an outer ring 27C. The rolling elements 27A are spherical members, and a large number of them are arranged circumferentially around the rotating part 31. The rolling elements 27A are sandwiched between the inner ring 27B and the outer ring 27C. The inner ring 27B and the outer ring 27C have grooves along which the rolling elements 27A slide. Of the inner ring 27B and the outer ring 27C, the inner ring 27B is arranged closer to the rotating part 31. The inner ring 27B is connected to the rotating part 31. The outer ring 27C abuts against the inner surface of the housing 29. That is, the outer ring 27C is held by the housing 29.

[0029] The structure of the rotary bearing 28 is the same as that of the rotary bearing 27. That is, the rotary bearing 28 includes a rolling element 28A, an inner ring 28B, and an outer ring 28C. The rolling element 28A is sandwiched between the inner ring 28B and the outer ring 28C. The inner ring 28B abuts against the outer peripheral surface of the rotating part 31. The outer ring 28C abuts against the inner peripheral surface of the housing 29.

[0030] 3, an internal spacer 33, a preload spring 35, an external spacer 37, and a sliding member 39 are further disposed inside the housing 29. The internal spacer 33 is a ring-shaped member, and is inserted on the outer periphery of the rotating part 31. The internal spacer 33 is disposed between the rotary bearing 27 and the rotary bearing 28.

[0031] The preload spring 35 is a ring-shaped spring and is disposed between the rotary bearing 27 and the rotary bearing 28. The preload spring 35 is inserted onto the outer periphery of the inner spacer 33. The outer spacer 37 is a ring-shaped member and is inserted onto the inner periphery of the housing 29. The outer spacer 37 is fixed to the housing 29 with a screw 41. One end face of the outer spacer 37 abuts against the end face of the outer ring 28C. A step 43 is formed on the inner periphery of the outer spacer 37, and the step 43 abuts against the end face of the preload spring 35.

[0032] The sliding member 39 is a ring-shaped member as a whole, and is inserted between the preload spring 35 and the rotary bearing 27. The sliding member 39 is disposed so as to be slidable in the direction of the rotation axis P relative to the inner circumferential surface of the housing 29. The sliding direction of the sliding member 39 is indicated by an arrow F3 in Figure 3.

[0033] One end face of the sliding member 39 abuts against the end face of the outer ring 27C. A step 45 is formed on the inner circumferential side of the sliding member 39. A preload spring 35 is incorporated in a compressed state between the step 43 of the external spacer 37 and the step 45 of the sliding member 39. In other words, the preload spring 35 biases the end face of the outer ring 27C of the rotation bearing 27 in the direction of the rotation axis P via the sliding member.

[0034] The preload spring 35 biases the end face of the outer ring 27C, thereby applying a constant preload to the rotary bearing 27 and the rotary bearing 28. The direction in which the preload spring 35 applies a preload to the outer ring 27C of the rotary bearing 27 is indicated by arrow F1 in Figure 3. The direction in which the preload spring 35 applies a preload to the outer ring 28C of the rotary bearing 28 is indicated by arrow F2 in Figure 3. The preload spring 35 applies a preload to the outer ring 27C, thereby stabilizing the rolling track of the rolling part 27A of the rotary bearing 27. The preload spring 35 applies a preload to the outer ring 28C, thereby stabilizing the rolling track of the rolling part 28A of the rotary bearing 28.

[0035] A threaded portion 47 is formed on the end of the rotating portion 31 opposite the rotating anode 23. A nut 49 is threadedly engaged with the threaded portion 47. By threading the nut 49 onto the threaded portion 47, the inner ring 27B, the inner ring 28B, and the inner spacer 33 are fixed in the direction of the rotation axis P.

[0036] <Explanation of Sliding Member> The sliding member 39 will be described in detail with reference to Fig. 4 to Fig. 6. Fig. 4 is a vertical cross-sectional view of the sliding member 39. Fig. 5 is a perspective view of the sliding member 39. Fig. 6 is a vertical cross-sectional view showing a state in which the sliding member 39 abuts against the housing 29.

[0037] The sliding member 39 includes a first sliding portion 51, a second sliding portion 53, and a groove portion 55. The first sliding portion 51 is formed on the end of the outer circumferential surface of the sliding member 39 that is farther from the rotating anode 23. The second sliding portion 53 is formed on the end of the outer circumferential surface of the sliding member 39 that is closer to the rotating anode 23. The second sliding portion 53 is disposed at a position spaced a predetermined distance from the first sliding portion 51 in the direction of the rotation axis P.

[0038] The groove portion 55 is formed on the outer peripheral surface of the sliding member 39, between the first sliding portion 51 and the second sliding portion 53. In other words, the outer peripheral portion 50 of the sliding member 39 includes the first sliding portion 51, the second sliding portion 53, and the groove portion 55.

[0039] The first sliding portion 51 and the second sliding portion 53 each have a ring-like configuration and protrude in the radial direction of the sliding member 39 compared to the groove portion 55. The outer peripheral surface of the first sliding portion 51 extends in the circumferential direction of the sliding member 39, and the first sliding portion 51 abuts against the inner peripheral surface of the housing 29 via this outer peripheral surface. The outer peripheral surface of the second sliding portion 53 extends in the circumferential direction of the sliding member 39, and the second sliding portion 53 abuts against the inner peripheral surface of the housing 29 via this outer peripheral surface.

[0040] That is, when the ring-shaped sliding member 39 is inserted into the housing 29, the first sliding portion 51 and the second sliding portion 53 each come into contact with the inner circumferential surface of the housing 29, as shown in Fig. 6. The first sliding portion 51 and the second sliding portion 53 then slide in the x direction along the inner circumferential surface of the housing 29. That is, in the sliding member 39 according to the first embodiment, the sliding surface that slides against the housing 29 extends in the circumferential direction of the sliding member 39.

[0041] The groove 55 is configured to be spaced apart from the inner circumferential surface of the housing 29. That is, a step 57 is formed at the boundary between the first sliding portion 51 and the groove 55. Furthermore, a step 59 is formed at the boundary between the second sliding portion 53 and the groove 55. The step 57 and the step 59 extend in the radial direction of the sliding member 39. In the first embodiment, the groove 55 is formed to extend in the circumferential direction of the sliding member 39.

[0042] The depth d1 of the groove 55 in the radial direction of the sliding member 39 is set to a degree that reliably prevents the outer peripheral surface of the groove 55 from contacting the inner peripheral surface of the housing 29. In other words, when the sliding member 39 is inserted into the housing 29, a gap Kp is formed between the groove 55 of the sliding member 39 and the inner peripheral surface of the housing 29, as shown in FIG. 6 . Therefore, the area over which the outer peripheral portion 50 of the sliding member 39 contacts the inner peripheral surface of the housing 29 is reduced by the area over which the gap Kp is formed. In other words, the area of ​​the sliding member 39 that slides along the inner peripheral surface of the housing 29 is reduced by the area over which the groove 55 is formed.

[0043] <Effects of First Embodiment> Here, the effects of the configuration of the first embodiment will be described. The sliding member 39 according to the first embodiment has a groove 55, which corresponds to a non-sliding surface with respect to the housing 29, disposed between a first sliding portion 51 and a second sliding portion 53, which correspond to sliding surfaces with respect to the housing 29. By providing the sliding member 39 with the groove 55, it is possible to reduce noise and vibration generated in the rotating anode X-ray tube assembly 1 and to extend the life of the rotating anode X-ray tube assembly 1.

[0044] First, a description will be given of a first mechanism for reducing noise and vibration generated in the rotating anode X-ray tube assembly 1 by using the sliding member 39 according to the first embodiment. In the rotating anode X-ray tube assembly 1, the sliding member 39 repeatedly slides along the inner peripheral surface of the housing 29, causing scratches to form on the outer peripheral surface 50 of the sliding member 39. Then, as the sliding between the outer peripheral surface 50 of the sliding member 39 and the inner peripheral surface of the housing 29 continues in a state in which scratches have formed, metal adhesion occurs on the outer peripheral surface 50 of the sliding member 39.

[0045] That is, by reducing the area of ​​the portion of the sliding member 39 that slides against the housing 29, it is possible to reduce the range in which scratches and metal adhesion occur on the sliding member 39. In other words, by providing the sliding member 39 with the groove portion 55 in the first embodiment, it is possible to reduce the range in which scratches and metal adhesion occur. As a result, it is possible to avoid a decrease in the slidability of the sliding member 39 relative to the housing 29 due to scratches and metal adhesion.

[0046] The trajectories of the rolling parts 27A and 28A are stabilized by improving the sliding properties of the sliding member 39. Therefore, the noise and vibration generated in the rotating anode X-ray tube assembly 1 can be reduced, and the life of the rotating anode X-ray tube assembly 1 can be extended.

[0047] Next, a second mechanism for reducing noise and vibration generated in the rotating anode X-ray tube assembly 1 by using the sliding member 39 according to the first embodiment will be described while comparing it with the structure of the sliding member Sh according to the conventional embodiment.

[0048] FIG. 7 is a longitudinal cross-sectional view of a sliding member Sh according to a conventional embodiment. While the sliding member 39 according to the first embodiment has a groove 55 on the outer circumferential portion 50, the sliding member Sh according to the conventional embodiment does not have a groove 55 on the outer circumferential surface G1. That is, the sliding member Sh has a uniform diameter along the direction of the rotation axis P. That is, when the conventional sliding member Sh is inserted into the housing 29, as shown in FIG. 8, the sliding member Sh abuts against the inscribed surface of the housing 29 over the entire outer circumferential surface G1. In other words, the entire outer circumferential surface G1 of the sliding member Sh slides along the inner circumferential surface of the housing 29.

[0049] Here, the inventors have conducted extensive research and found the following facts. First, it was found that when rotation noise and vibration increase in a rotating anode X-ray tube assembly, scratches and metal adhesion occur over a wide area on the outer circumferential surface G1 of the sliding member Sh. Second, it was found that the metal adhesion spreads along the sliding surface of the sliding member Sh relative to the housing 29.

[0050] Fig. 9(a) is a longitudinal cross-sectional view showing a state where scratches and metal adhesion have occurred at a starting point Da on the outer peripheral surface G1 of the slide member Sh. Fig. 9(b) is a longitudinal cross-sectional view showing a state where the scratches and metal adhesion have expanded in a conventional slide member Sh. Fig. 10 is a perspective view showing a state where the scratches and metal adhesion have expanded in a conventional slide member Sh. The area where scratches and metal adhesion have occurred is indicated by the symbol Me.

[0051] When the sliding member Sh slides against the housing 29 in a state where scratches and metal adhesion have occurred at the starting point Da, the area Me where scratches and metal adhesion occur expands along the sliding surface. In the conventional sliding member Sh, the entire outer peripheral surface G1 is the surface that slides against the housing 29. Therefore, as shown in Figures 9(b) and 10, the area Me where scratches and metal adhesion occur expands to the entire outer peripheral surface G1.

[0052] As described above, in the conventional sliding member Sh, scratches and metal adhesion easily spread over the entire outer peripheral surface G1, making scratches and metal adhesion likely to occur over a wide area. When scratches and metal adhesion occur over a wide area, the sliding function of the sliding member Sh relative to the housing 29 is likely to deteriorate. When the sliding function of the sliding member Sh deteriorates, the function of transmitting preload from the preload spring 35 to the outer ring 27C via the sliding member Sh deteriorates. When sufficient preload is not transmitted to the outer ring 27C, the rolling track of the rolling part 27A becomes unstable, and it is thought that when the conventional sliding member Sh is used, noise and vibration generated in the rotating anode X-ray tube assembly are likely to increase.

[0053] On the other hand, when the sliding member 39 according to the first embodiment is provided, the area of ​​the sliding member 39 that comes into contact with the housing 29 is limited to the first sliding portion 51 and the second sliding portion 53 of the outer circumferential portion 50. Therefore, the area that can become the starting point Da for scratches and metal adhesion is limited to the first sliding portion 51 and the second sliding portion 53 of the outer circumferential portion 50.

[0054] The first sliding portion 51 and the second sliding portion 53 are separated by a groove portion 55 and are disposed with a predetermined gap therebetween. The groove portion 55 of the outer circumferential portion 50 does not come into contact with the housing 29, and therefore does not serve as a sliding surface for the housing 29. Therefore, as shown in Fig. 10(a) , if scratches and metal adhesion occur in the first sliding portion 51, the groove portion 55 will prevent the scratches and metal adhesion that have occurred at the starting point Da from expanding.

[0055] Specifically, the area Me where scratches and metal adhesion occur is prevented from expanding (see symbol V) at the step 57, which is the boundary between the groove 55 and the first sliding portion 51. As a result, scratches and metal adhesion that occur at the first sliding portion 51 are reliably prevented from expanding to at least the second sliding portion 53. Therefore, in the sliding member 39 according to the first embodiment, the area Me where scratches and metal adhesion occur can be limited to the inside of the first sliding portion 51.

[0056] Similarly, when scratches and metal adhesion occur in the second sliding portion 53 of the sliding member 39, the range Me where scratches and metal adhesion occur does not extend beyond the groove portion 55 to the first sliding portion 51. That is, the range Me where scratches and metal adhesion occur is prevented from extending at the step portion 59, which is the boundary between the groove portion 55 and the second sliding portion 53. As a result, the range Me where scratches and metal adhesion occur can be limited to the inside of the second sliding portion 53.

[0057] In this way, in the sliding member 39 according to the first embodiment, the groove 55, which corresponds to a non-sliding surface with respect to the housing 29, is disposed between the first sliding portion 51 and the second sliding portion 53, which correspond to sliding surfaces with respect to the housing 29. By disposing the groove 55, which is a non-sliding surface, it is possible to prevent scratches and metal adhesion from occurring in the groove 55, and therefore it is possible to narrow the range Me of the sliding member 39 where scratches and metal adhesion occur.

[0058] Furthermore, the groove 55 can prevent the range Me where scratches and metal adhesion occur from expanding from the first sliding portion 51 to the second sliding portion 53, thereby further narrowing the range Me where scratches and metal adhesion occur in the sliding member 39. Therefore, the width w1 of the groove 55 is determined to be a distance sufficient to prevent scratches and metal adhesion from expanding from the first sliding portion 51 to the second sliding portion 53. As an example, the widths of the first sliding portion 51 and the second sliding portion 53 in the x direction are approximately 1 to 2 mm, and the width w1 of the groove 55 is approximately 6 to 10 mm.

[0059] Furthermore, the sliding member 39 according to the first embodiment abuts against the inner circumferential surface of the housing 29 at the first sliding portion 51 and the second sliding portion 53, which are disposed at a predetermined distance from each other. In this case, the housing 29 holds the sliding member 39 in a plurality of regions that are spaced apart from each other. Holding the sliding member 39 in a plurality of regions improves the stability of the sliding member 39 sliding against the housing 29 compared to a configuration in which the sliding member 39 is held in a single region. In other words, compared to a configuration in which the sliding member 39 abuts against the inner circumferential surface of the housing 29 at one location, a configuration in which the sliding member 39 abuts against the inner circumferential surface of the housing 29 at two or more locations can greatly improve the stability of the sliding member 39 in the rotating anode X-ray tube assembly 1. Second embodiment

[0060] Next, a second embodiment of the present invention will be described. Note that the same components as those in the rotating anode X-ray tube assembly 1 described in the first embodiment are denoted by the same reference numerals, and only the sliding member 39A, which is a different component, will be described in detail.

[0061] Fig. 13 is a longitudinal cross-sectional view, as seen from the side, showing a sliding member 39A according to the second embodiment. Fig. 14 is a perspective view showing the sliding member 39A according to the second embodiment. The sliding member 39A is a ring-shaped member as a whole, and includes a plurality of sliding portions 61 and a plurality of groove portions 63. In the second embodiment, the sliding member 39A includes six sliding portions 61. The sliding portions 61 are distinguished from one another by being referred to as sliding portions 61a to 61f.

[0062] Each of the sliding portions 61a to 61f is a columnar member extending in the x direction, i.e., in the direction of the rotation axis P. Each of the sliding portions 61a to 61f is arranged at a predetermined interval on the outer periphery of the sliding member 39A. In FIG. 13, the sliding portion 61 arranged on the upper side of the sliding member 39A is designated as sliding portion 61a. Sliding portions 61b to 61f are arranged in this order in a clockwise direction on the outer periphery of the sliding member 39A. In the second embodiment, the sliding portion 61a corresponds to the first sliding portion. Sliding portions 61b and 61f adjacent to sliding portion 61a with the groove portion 63 therebetween correspond to the second sliding portion.

[0063] The grooves 63 are formed between adjacent sliding portions 61. In the second embodiment, the grooves 63 are formed to extend in the x direction. That is, the grooves 55 according to the first embodiment and the grooves 63 according to the second embodiment extend in different directions.

[0064] The outer peripheral surfaces of the sliding portions 61a to 61f protrude in the radial direction of the sliding member 39A compared to the outer peripheral surface of the groove portion 63. That is, as shown in Fig. 15 , when the sliding member 39A is inserted into the housing 29, the outer peripheral surface of each of the sliding portions 61a to 61f abuts against the inner peripheral surface of the housing 29.

[0065] The depth d2 of the groove 63 is set to a degree that reliably prevents the outer peripheral surface of the groove 63 from contacting the inner peripheral surface of the housing 29. In other words, when the sliding member 39A is inserted into the housing 29, a gap Kp is formed between the groove 63 of the sliding member 39A and the inner peripheral surface of the housing 29. That is, the outer peripheral surface of the sliding portion 61 corresponds to a sliding surface with respect to the housing 29. On the other hand, the outer peripheral surface of the groove 63 corresponds to a non-sliding surface with respect to the housing 29.

[0066] In the second embodiment, similarly to the first embodiment, the area where the gap Kp is formed reduces the area where the sliding member 39A contacts the inner circumferential surface of the housing 29. In other words, the area where the sliding member 39A slides along the inner circumferential surface of the housing 29 reduces by the area where the groove 63 is formed. Therefore, the area where scratches and metal adhesion occur in the sliding member 39A can be reduced.

[0067] The width w2 of the groove 63 is determined to be a sufficient distance to prevent scratches and metal adhesion from spreading from one sliding portion 61 to an adjacent sliding portion 61. As an example, the width of the sliding portions 61a and 61b in the circumferential direction of the sliding member 39A is about 1 to 2 mm, and the width w1 of the groove 63 is about 6 to 10 mm.

[0068] In this way, each of the multiple sliding portions 61 is separated by the groove portion 63, which is a non-sliding surface. Therefore, even if scratches and metal adhesion occur in one sliding portion 61, the scratches and metal adhesion spread along the sliding surface, and the groove portion 63 prevents the scratches and metal adhesion that occurred in one sliding portion 61 from spreading to the other sliding portions 61. Therefore, similar to the sliding portion 39, the sliding member 39A can also be prevented from having scratches and metal adhesion over a wide area. Therefore, it is possible to prevent the slidability of the sliding member 39A from being reduced due to scratches and metal adhesion, thereby reducing noise and vibration in the rotating anode X-ray tube assembly 1 and extending the life of the rotating anode X-ray tube assembly 1.

[0069] <Effects of the Configuration of the Embodiment> (Item 1) The rotating anode X-ray tube assembly 1 according to this embodiment includes a cathode 21 that emits electrons, a rotating anode 23 that generates X-rays using the electrons emitted from the cathode 21, a rotating section 31 that supports and rotates the rotating anode 23, a rotary bearing 27 that is arranged in the circumferential direction of the rotating section 31 and has an outer ring 27C and an inner ring 27B that sandwich a rolling element 27A, a housing 29 that holds the outer ring 27C, a preload spring 35 that applies a preload to the outer ring 27C in the direction of the rotation axis P of the rotating anode 23, and a spring 35 that is arranged between the outer ring 27C and the preload spring 35 and that is arranged in the housing 29. and an envelope 19 that contains the cathode 21, the rotary anode 23, the rotating part 31, the rotary bearing 27, the housing 29, the preload spring 35, and the sliding member 39 in a vacuum atmosphere. The sliding member 39 includes a first sliding part 51 that can slide along the inner peripheral surface of the housing 29, a second sliding part 53 that is disposed at a predetermined distance from the first sliding part 51 and can slide along the inner peripheral surface of the housing 29, and a groove part 55 that is formed between the first sliding part 51 and the second sliding part 53.

[0070] The rotating anode X-ray tube assembly 1 described in paragraph 1 includes a sliding member 39 disposed between the outer ring 27C of the rotary bearing 27 and the preload spring 35. The sliding member 39 slides in the direction of the rotation axis P of the rotary anode 23 along the inner circumferential surface of the housing 29 that holds the outer ring 27C of the rotary bearing 27. The sliding member 39 includes a first sliding portion 51 and a second sliding portion 53 that are slidable along the inner circumferential surface of the housing 29. The second sliding portion 53 is disposed at a predetermined distance from the first sliding portion 51.

[0071] A groove 55 is formed between the first sliding portion 51 and the second sliding portion 53. That is, the contact area between the inner surface of the housing 29 and the sliding member 39 is reduced by the area of ​​the groove 55. This reduces scratches and metal adhesion caused by friction between the sliding member 39 and the housing 29. As a result, the preload is efficiently transmitted from the preload spring 35 to the rotary bearing 27 via the sliding member 39, further stabilizing the rolling trajectory of the rolling portion 27A of the rotary bearing 27. This prevents noise and vibration from occurring in the rotary anode X-ray tube assembly 1. Furthermore, abnormal wear of the solid lubricant and deterioration of the sliding member 39 can be prevented, thereby extending the life of the rotary anode X-ray tube assembly 1.

[0072] (Item 2) In the rotating anode X-ray tube assembly described in Item 1, the first sliding portion 51 and the second sliding portion 53 are arranged at a predetermined interval in the direction of the rotation axis P of the rotating anode 23, and the groove portion 55 is formed to extend in the circumferential direction of the sliding member 39.

[0073] According to the rotating anode X-ray tube assembly 1 described in paragraph 2, the first sliding portion 51 and the second sliding portion 53 are arranged at a predetermined interval in the direction of the rotation axis P of the rotating anode 23. The groove 55 extends in the circumferential direction of the sliding member 39. In this case, the first sliding portion 51, the groove 55, and the second sliding portion 53 are arranged to be aligned in the direction of the rotation axis P. Therefore, the groove 55 can reliably prevent scratches and metal adhesion occurring on one of the first sliding portion 51 and the second sliding portion 53 from spreading to the other. Furthermore, a configuration in which the first sliding portion 51, the groove 55, and the second sliding portion 53 are aligned in the direction of the rotation axis P is easy to manufacture, and therefore the cost of the sliding member 39 can be reduced.

[0074] (Item 3) In the rotating anode X-ray tube assembly 1A described in Item 1, the first sliding portion 61 a and the second sliding portion 61 b ​​are arranged at a predetermined interval in the circumferential direction of the sliding member 39A, and the groove portion 63 is formed to extend in the direction of the rotation axis P of the rotating anode 23.

[0075] According to the rotating anode X-ray tube assembly 1A described in paragraph 3, the first sliding portion 61a and the second sliding portion 61b are arranged at a predetermined interval in the circumferential direction of the sliding member 39A. The groove 63 extends in the direction of the rotation axis P of the rotating anode 23. The first sliding portion 61a, the groove 63, and the second sliding portion 61b are arranged so as to be aligned in the circumferential direction of the sliding member 39A. Therefore, the groove 55 can reliably prevent scratches and metal adhesion occurring on one of the first sliding portion 61a and the second sliding portion 61b from spreading to the other. Furthermore, since the configuration in which the first sliding portion 61a, the groove 55, and the second sliding portion 61b are aligned in the circumferential direction of the sliding member 39A is easy to manufacture, the cost of the sliding member 39A can be reduced. <Other Embodiments> The embodiments disclosed herein are illustrative in all respects and are not limiting. The scope of the present invention includes the claims, and all modifications within the meaning and scope of the claims. For example, the present invention can be modified as follows.

[0076] (1) In the rotating anode X-ray tube assembly 1 according to the first embodiment, the sliding member 39 is not limited to the configuration including two sliding portions, the first sliding portion 51 and the second sliding portion 53. That is, the sliding member 39 may include three or more sliding portions. Fig. 16 is a perspective view showing, as an example, a sliding member 39B including three sliding portions.

[0077] The sliding member 39B includes a first sliding portion 51, a second sliding portion 53, and a third sliding portion 65. The third sliding portion 65 is disposed between the first sliding portion 51 and the second sliding portion 53. A groove portion 55a is formed between the first sliding portion 51 and the third sliding portion 65, and a groove portion 55b is formed between the third sliding portion 65 and the second sliding portion 53. That is, the outer circumferential portion 50 of the sliding member 39B is configured such that the first sliding portion 51, the groove portion 55a, the third sliding portion 65, the groove portion 55a, and the second sliding portion 53 are aligned in order in the x direction.

[0078] When the sliding member 39B is inserted into the housing 29, the first sliding portion 51, the second sliding portion 53, and the third sliding portion 65 of the outer circumferential portion 50 come into contact with the inner circumferential surface of the housing 29. That is, the housing 29 holds the sliding member 39B at three portions: the first sliding portion 51, the second sliding portion 53, and the third sliding portion 65. Therefore, compared to the sliding member 39 that is held by the housing 29 at two portions, the sliding member 39B can have improved stability during sliding.

[0079] (2) In the rotary anode X-ray tube assembly described above, the rotary bearing 28 of the rotary bearing 27 and the rotary bearing 28 is disposed on the side closer to the rotary anode 23, but the present invention is not limited to this. That is, as shown in Fig. 17 , the rotary bearing 27 may be disposed on the side closer to the rotary anode 23, and the rotary bearing 28 may be disposed on the side farther from the rotary anode 23. In this case, of the sliding member 39 and the external spacer 37, the sliding member 39 is disposed on the side closer to the rotary anode 23. The external spacer 37, which is disposed on the side farther from the rotary anode 23, is fixed to the housing 29 with screws 41.

[0080] DESCRIPTION OF SYMBOLS 1...rotating anode type X-ray tube device 5...X-ray tube 7...stator 19...envelope 21...cathode 23...rotating anode 25...rotating cylindrical portion 27...rotating bearing 27A...rolling element 27B...inner ring 27C...outer ring 28...rotating bearing 28A...rolling element 28B...inner ring 28C...outer ring 29...housing 31...rotating portion 33...inner spacer 35...preload spring 37...outer spacer 39...sliding member 51...first sliding portion 53...second sliding portion 55...groove portion 61...sliding portion 63...groove portion

Claims

a rotating anode that generates X-rays from the electrons emitted from the cathode; a rotary drive unit that supports and rotates the rotary anode; a rotary bearing that is arranged circumferentially on the rotary drive unit and has an outer ring and an inner ring that sandwich a rolling element; a holder that holds the outer ring; a preload applying unit that applies a preload to the outer ring in the direction of the rotation axis of the rotary anode; a sliding member that is arranged between the outer ring and the preload applying unit and slides along the inner surface of the holder in the direction of the rotation axis; and an envelope that contains the cathode, the rotary anode, the rotary drive unit, the rotary bearing, the holder, the preload applying unit, and the sliding member in a vacuum atmosphere, a groove formed between the first sliding portion and the second sliding portion.

2. A rotating anode X-ray tube assembly according to claim 1, wherein the first sliding portion and the second sliding portion are arranged at a predetermined interval in the direction of the rotation axis of the rotating anode, and the groove portion is formed so as to extend in the circumferential direction of the sliding member.

3. A rotating anode X-ray tube assembly according to claim 1, wherein the first sliding portion and the second sliding portion are arranged at a predetermined interval in the circumferential direction of the sliding member, and the groove portion is formed so as to extend in the direction of the rotation axis of the rotating anode.

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