JP2007068653A - Rolling bearing device for computed tomography - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the generation of vibration and noise and stably retain a favorable bearing performance. <P>SOLUTION: This device is formed by assembling a pair of ball bearings 10a and 10a back to back and clamps an inner ring spacer 21 between the inner end faces of a pair of inner rings 15a and 15a. An outer ring spacer 22 is provided between the inner end faces of a pair of outer rings 13 and 13, and a plurality of leaf springs 24 and 24 locked at an equal interval in the circumferential direction of both sides in the axial direction of the outer ring spacer 22 are resiliently pushed to the inner end faces of the respective outer rings 13 and 13. This constitution applies a prescribed fixed preload to the respective balls 11 and 11. The whole diameter is thus enlarged while the respective inner rings 15a and 15a and the respective outer rings 13 and 13 are extremely thinned relative to the whole diameter, so as to stably apply the prescribed preload though the respective members is easily thermally expanded. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is used to rotatably support a rotating member that fixes a radiation source such as an X-ray tube device and a radiation detection device of a computed tomography apparatus (CT scanner), which is a kind of medical equipment, with respect to a fixed base. The present invention relates to an improvement in a rolling bearing device for a computed tomography apparatus.

  A computed tomography apparatus called a CT scanner is used as a kind of medical equipment for efficiently performing diagnosis and examination of a patient in a hospital. In this computed tomography apparatus, X-rays emitted from an X-ray tube apparatus as a radiation source are passed through a subject and then received by a radiation detection apparatus. One example of such a computer tomography apparatus is described in Patent Document 1. As shown in FIG. 11, the computed tomography apparatus described in Patent Document 1 includes a bed part 2 for laying a subject 1 and an inspection arranged around the subject 1 by moving the bed part 2. Part (gantry part) 3. The inspection unit 3 includes a fixed base 5 having a cylindrical support unit 4 and a cylindrical rotating member 6 disposed around the support unit 4. By providing a rolling bearing 7 between the outer peripheral surface of the support portion 4 and the inner peripheral surface of the rotary member 6, the rotary member 6 is rotatably supported by the support portion 4. In addition, an X-ray tube device 8 and a radiation detection device 9 which are radiation sources are fixed to positions opposite to the radial direction of the rotating member 6. X-rays emitted by the X-ray tube device 8 are received by the radiation detection device 9 after passing through the subject 1. Further, the X-ray tube device 8 and the radiation detection device 9 rotate around the subject 1 together with the rotating member 6. Then, the data represented by the detection signal sent from the radiation detection device 9 is collected by a computer to reconstruct a tomographic image of the subject 1 and displayed on a display unit (not shown).

  As the rolling bearing 7 used in such a computer tomography apparatus, a single-row four-point contact ball bearing described in Patent Document 1, a double-row angular ball bearing described in Patent Document 2, and Patent Document 3 It has been conventionally considered to use ball bearings or the like that are simultaneously quenched on the entire circumference of the raceway surface. In any case, the rolling bearing 7 used in the computed tomography apparatus is an ultra-thin type in which the radial thickness of the inner ring and the outer ring is extremely small with respect to the entire diameter. Further, in the rolling bearing 7, the diameter becomes very large as the inner diameter and the outer diameter exceed 500 mm. In such a rolling bearing 7, since the entire surface area of the rolling contact portion is increased, the heat generated by the rotation is greatly increased. Further, since the inner ring and the outer ring become ultra-thin relative to the entire diameter, the heat capacity of these inner and outer rings is reduced, and the temperature rise during use of these inner and outer rings becomes very large. For this reason, it is conventionally considered difficult to use the rolling bearing 7 in a setting in which the internal clearance is negative (−) by applying a preload to the rolling bearing 7.

  That is, the rolling bearing 7 used for the rotation support portion of the computed tomography apparatus has been generally used in the state where the axial internal gap is set to a positive (+) gap. However, when such a rolling bearing 7 for a computed tomography apparatus is used with a positive internal clearance set, for example, when the rolling bearing 7 is an angular ball bearing, Since the rigidity becomes low and the behavior of each ball during rotation becomes unstable, vibration and noise are likely to occur.

  On the other hand, in the case of the rolling bearing for the computer tomography apparatus described in Patent Document 2, it is used in a state where a fixed position preload is applied to the double-row angular ball bearing. When used in a state where a fixed preload is applied in this way, it can be said that the rigidity of the ball bearing can be increased to some extent, and the occurrence of vibration and noise cannot be suppressed to some extent. However, when the angular type ball bearing described in Patent Document 2 is used by being incorporated in the rotation support portion of the computer tomography apparatus, the entire diameter of the ball bearing actually increases, and the entire diameter On the other hand, the thickness in the radial direction of both the inner and outer wheels is extremely small and ultra-thin. For this reason, both the inner and outer wheels are likely to thermally expand during rotation, making it difficult to stably apply a predetermined preload.

  Further, as shown in FIG. 12, a pair of ball bearings 10 and 10 each of which is an angular type are combined, and in a state where a pre-position preload is applied to the balls 11 and 11 constituting the ball bearings 10 and 10, respectively. The ball bearing device 12 to be used has also been conventionally considered. In the case of this ball bearing device 12, the both ball bearings 10, 10 are brought into contact with the inner end surfaces on the shoulder portions 14, 14 side of the respective outer rings 13, 13 and are combined in a so-called rear combination, An axial gap 16 is formed between the inner end faces of the inner rings 15, 15 facing each other.

When such a ball bearing device 12 is used by being incorporated in a rotation support portion of a computed tomography apparatus, it is between the inner peripheral surface of the rotating member 6 and the outer peripheral surface of the support portion 4 (see FIG. 11) of the fixed base 5. The ball bearing device 12 is incorporated. Further, by applying a force in a direction approaching from both sides in the axial direction to each of the inner rings 15, 15 that are externally fitted to the outer peripheral surface of the support portion 4, the axial gap 16 is reduced to 0, etc. A predetermined fixed position preload is applied. However, even when such a ball bearing device 12 is used by being incorporated in the rotation support portion of the computed tomography apparatus, the diameters of the inner and outer wheels 15 and 13 are increased, and the inner diameter of the inner and outer wheels 15 and 13 is larger than the total diameter. The outer wheels 15 and 13 have a very small thickness in the radial direction and are extremely thin. For this reason, the inner and outer wheels 15 and 13 are likely to thermally expand during rotation, and it is difficult to stably apply a predetermined preload.
As described above, when a rolling bearing is used for a computer tomography apparatus, a specific problem occurs. Therefore, it is desired to realize a structure that can solve this problem.

JP 2002-81442 A Japanese Patent Laid-Open No. 2005-3152 JP 2002-174251 A

  The rolling bearing device for a computer tomography apparatus of the present invention has a structure in which a preload is applied in order to effectively suppress the generation of vibration and noise in view of the above-described circumstances, and this preload fluctuates excessively during rotation of the bearing. The invention has been invented to realize a structure capable of stably maintaining good bearing performance by suppressing the occurrence of this and continuously applying the appropriate preload.

  The rolling bearing device for the computed tomography apparatus of the present invention is the same as the conventionally known rolling bearing device for the computed tomography apparatus, in which the rotating member that fixes the radiation source and the radiation detecting device is rotated with respect to the fixed base. Used to support freely.

  In particular, among the rolling bearing devices for a computer tomography apparatus according to the present invention, the rolling bearing device for a computer tomography apparatus according to claim 1 has an elastic member between a pair of rolling bearings facing each other in the axial direction. By providing, a constant pressure preload is applied to each rolling element of each rolling bearing.

  According to a fourth aspect of the present invention, there is provided a rolling bearing device for a computer tomography apparatus comprising a pair of outer rings or inner rings and an inner ring or outer ring having an integral structure opposed to the pair of outer rings or inner rings in the radial direction. In addition, a constant pressure preload is applied to each rolling element by providing an elastic member between a pair of outer rings or inner rings facing each other in the axial direction.

  In the case of the rolling bearing device for the computer tomography apparatus of the present invention configured as described above, since a preload is applied to each rolling element, the rolling bearing is different from the structure having a positive internal clearance. In addition, each rolling element rotates stably, and generation of vibration and noise can be suppressed. Further, by applying the preload, the rigidity can be increased and the runout of the rolling bearing can be reduced. For this reason, it is possible to effectively prevent inconveniences such as disturbance of the image of the computed tomography apparatus. Moreover, in the case of the present invention, the diameter and the ultra-thinness are set despite the fact that the components of the rolling bearing are likely to thermally expand due to the temperature rise during rotation. It is possible to prevent the preload from fluctuating excessively. That is, even if each component of the rolling bearing is deformed in accordance with a temperature change during use, the constant pressure preload is applied to the rolling bearing, so that the (negative) preload gap can be stably maintained. That is, unlike the case of the present invention, the structure for applying a fixed position preload to the rolling bearing as shown in FIG. 12 does not have an alignment function when thermally expanded. On the other hand, in the case of the present invention in which constant pressure preload is applied to the rolling bearing, since the alignment function is provided within the range of the spring constant, the (negative) preload gap can be stably maintained. In particular, in the case of an ultra-thin type rolling bearing having an outer ring outer diameter of 800 mm or more, an inner ring inner diameter of 500 mm or more, and a bearing width (axial dimension) of 25.4 mm or more, a constant pressure preload should be applied. The effect obtained by becomes more remarkable. As a result, according to the present invention, good bearing performance can be stably maintained.

  Preferably, when implementing the configuration described in claim 1 above, for example, as described in claim 2, elastic members are provided at a plurality of circumferentially equidistant positions between the pair of rolling bearings. Thus, a constant pressure preload is applied to each rolling element of each rolling bearing.

  More preferably, as described in claim 3, each of the elastic members is disposed in a recess or a through hole provided in a spacer disposed between the pair of rolling bearings.

  Further, when implementing the configuration described in claim 4 above, preferably, for example, as described in claim 5, it is elastic at a plurality of circumferentially equidistant positions between the pair of outer rings or inner rings. By providing the members, a constant pressure preload is applied to each rolling element.

  More preferably, as described in claim 6, each of the elastic members is disposed in a recess or a through hole provided in a spacer disposed between the pair of outer rings or inner rings.

  1-3 show Example 1 of the present invention corresponding to claims 1 to 3. The ball bearing device 12a, which is a rolling bearing device for the computed tomography apparatus of the present embodiment, is used for the rotation support portion of the rotating member 6 of the computed tomography apparatus shown in FIG. 11, and each is angular. A pair of ball bearings 10a and 10a which are molds are provided. Each of these ball bearings 10a and 10a includes inner rings 15a and 15a provided with inner ring raceways 17 and 17 on the outer peripheral surface, outer rings 13 and 13 provided with outer ring raceways 18 and 18 on the inner peripheral face, and inner and outer both ring raceways. A plurality of balls 11, 11 each provided as a rolling element are provided between 17 and 18 so as to freely roll. These balls 11, 11 are held in a plurality of pockets 20, 20 provided in the cages 19, 19 so as to be freely rollable. Further, among the inner peripheral surfaces at both ends of each outer ring 13, 13, shoulder portions 14, 14 are provided only on the inner end inner peripheral surface on the side where each outer ring 13, 13 faces each other.

The outer rings 13 and 13 and the inner rings 15a and 15a are made of steel such as bearing steel such as SUJ2 and SUJ3, stainless steel such as SUS440C, carburized quenching treatment or carbonitriding quenching treatment. Yes. The balls 11 and 11 are made of bearing steel such as SUJ2, stainless steel such as SUS440C, steel such as surface hardened steel subjected to carbonitriding and quenching, or ceramics such as Si ₃ N ₄ (silicon nitride). It is made.

  A short cylindrical inner ring spacer 21 is sandwiched between the inner end faces of the pair of inner rings 15a and 15a that constitute each of the ball bearings 10a and 10a. Further, an outer ring spacer 22 is disposed between the inner end faces of the pair of outer rings 13 and 13 that constitute the ball bearings 10a and 10a. As shown in FIGS. 2 and 3, the outer ring spacer 22 has a short cylindrical shape, and circular annular recesses 23 and 23 having the same dimensions are formed at the radial center of both side surfaces in the axial direction. . And the leaf | plate springs 24 and 24 which are elastic members are latched in the circumferential direction equal intervals several places on the same periphery of these annular recessed parts 23 and 23. FIG. Each of the leaf springs 24 and 24 has a bottomed short cylindrical shape, and the cylindrical portions 25 and 25 are inclined in a direction in which the diameter increases toward the opening end. And the opening side edge of each leaf | plate spring 24 and 24 is latched to the inner diameter side of the bottom part of each said annular recessed part 23 and 23, and an outer diameter side both-ends edge.

  Further, the axial dimensions of the outer wheels 15a and 13 among the ball bearings 10a and 10a are the same. An axial gap 26 is formed between the inner end faces of the pair of outer rings 13 and 13 with the inner ring spacer 21 sandwiched between the inner end faces of the pair of inner rings 15a and 15a. I have to. Also, the axial length L (FIG. 2) in the free state of the plate springs 24, 24, in which a plurality of plate springs 24, 24 are engaged with the annular recesses 23, 23 of the outer ring spacer 22, The dimension of each part is regulated so that the axial dimension of the gap 26 is slightly reduced. Then, in a state where the outer ring spacer 22 is disposed between the inner end surfaces of the outer rings 13, 13, the end surfaces of the leaf springs 24, 24 are elastically applied to the inner end surfaces of the outer rings 13, 13. Pressed. The elastic force applied to each outer ring 13 and 13 by each leaf spring 24 and 24 is made substantially uniform between the leaf springs 24 and 24. With this configuration, a predetermined constant pressure preload is applied to the balls 11 and 11 of the ball bearings 10a and 10a. In this state, each ball bearing 10a, 10a is combined so that it may become a back surface combination.

  The ball bearing device 12a configured in this manner is incorporated between the outer peripheral surface of the support portion 4 of the fixed base 5 and the inner peripheral surface of the rotating member 6 of the computed tomography apparatus as shown in FIG. use. At this time, the outer ring spacer 22 that locks the plurality of leaf springs 24, 24 is fitted into the inner peripheral surface of the rotating member 6 by gap fitting. Of the ball bearings 10a and 10a, the outer ring 13 constituting at least one of the ball bearings 10a is also fitted into the inner peripheral surface of the rotating member 6 by a clearance fit. And the rotating member 6 which fixed the X-ray tube apparatus 8 and the radiation detection apparatus 9 (FIG. 11) with respect to the fixed base 5 is rotatably supported by the said ball bearing apparatus 12a.

  In the case of the rolling bearing device for the computed tomography apparatus of the present embodiment constructed and used as described above, a preload is applied to each of the balls 11, 11 so that each ball bearing has a positive internal clearance. Unlike the case of the structure, each ball 11, 11 rotates stably, and generation of vibration and noise can be suppressed. Further, the rigidity can be increased by applying the preload, and the runout of the ball bearings 10a and 10a can be reduced. For this reason, it is possible to effectively prevent inconveniences such as disturbance of the image of the computed tomography apparatus.

In addition, in the case of the present embodiment, the diameter of the ball bearings 10a and 10a is likely to be thermally expanded due to the increase in temperature during rotation due to the large diameter and the ultra thin wall. Nevertheless, it is possible to prevent the set preload from fluctuating excessively. That is, even if each constituent member such as the inner rings 15a and 15a and the outer rings 13 and 13 of the ball bearings 10a and 10a is deformed in accordance with a temperature change during use, the leaf springs 24, Since the constant pressure preload of 24 is applied, the (negative) preload gap can be stably maintained. That is, unlike the case of the present embodiment, in the case of a structure in which a fixed position preload is applied to each of the ball bearings 10 and 10 as shown in FIG. 12 described above, there is no alignment function when thermally expanded. On the other hand, in the case of the present embodiment in which constant pressure preload is applied to the ball bearings 10a and 10a, the thermal expansion of the constituent members of the ball bearings 10a and 10a is provided because the alignment function is provided within the range of the spring constant. Regardless of this, the (negative) preload gap can be maintained stably. In particular, an outer diameter D ₁₃ of the outer ring 13, 13 is 800mm or more, with an inner ring 15a, an inner diameter d _15a of 15a is 500mm or more, of the entire bearing width (axial dimension) W is rolling over ultra thin type 25.4mm In the case of a bearing device, the effect obtained by applying a constant pressure preload becomes more prominent. As a result, according to the present embodiment, good bearing performance can be stably maintained.

  Further, when the ball bearings 10a and 10a are combined in a rear combination as in the present embodiment, the ball bearings 10a and 10a are combined in a front combination as in the second embodiment shown in FIG. 4 described later. As a result, the moment rigidity of the rotation support portion can be increased.

  In the present embodiment, the leaf springs 24, 24 for applying a constant pressure preload are not limited to those having the shape as shown in the figure, but the end portions of the annular recesses 23, 23 are provided. As long as it can be locked, those having various shapes can be used. For example, instead of the leaf springs 24, 24, an annular disc spring or a wave washer (wave washer) that has been widely used can be used.

  Next, FIG. 4 shows Embodiment 2 of the present invention, which also corresponds to claims 1 to 3. In the case of the ball bearing device 12b, which is a rolling bearing device for the computed tomography apparatus of the present embodiment, the pair of ball bearings 10a and 10a constituting the above-described embodiment 1 are replaced by shoulder portions of the outer rings 13 and 13, respectively. 14, 14 is a front combination in which 14 and 14 are combined so as to be located on the outer side on the side away from each other. A short cylindrical outer ring spacer 27 is sandwiched between the inner end surfaces of the pair of outer rings 13 and 13, and an inner ring spacer 28 is disposed between the inner end surfaces of the pair of inner rings 15a and 15a. ing. This inner ring spacer 28 is the same as that of the outer ring spacer 22 used in the first embodiment described above having a reduced overall diameter.

  The leaf springs 24 and 24 are respectively locked at a plurality of circumferentially equidistant portions of the annular recesses 23 and 23 provided on both side surfaces in the axial direction of the inner ring spacer 28. Then, in a state where the pair of ball bearings 10a, 10a are combined in a front combination, the leaf springs 24, 24 locked to the inner ring spacer 28 are attached to the inner end surfaces of the inner rings 15a, 15a. It is pressed elastically.

When the ball bearing device 12b is provided between the outer peripheral surface of the support 4 of the fixed base 5 of the computed tomography apparatus and the inner peripheral surface of the rotating member 6 (see FIG. 11), the inner ring spacer 28 is provided. Is externally fitted to the outer peripheral surface of the support portion 4 by a gap fit. Of the ball bearings 10 a and 10 a, the inner ring 15 a constituting at least one of the ball bearings 10 a is also fitted on the outer peripheral surface of the support portion 4 by a clearance fit.
Since other configurations and operations are the same as in the case of the above-described first embodiment, the same parts are denoted by the same reference numerals, and redundant description is omitted.

  Next, FIG. 5 shows Embodiment 3 of the present invention corresponding to claims 1 and 2. In the case of the ball bearing device 12c, which is a rolling bearing device for the computer tomography apparatus of the present embodiment, a pair of ball bearings 10a and 10a are combined in a rear combination, and a pair of inner rings 15a, The inner ring spacers 21 and 28 (see FIGS. 1 and 4 and the like) are not provided between the inner end faces of 15a, and both the inner end faces are directly abutted (without other members). In addition, a plurality of coil springs 29, each of which is an elastic member, are provided between the inner end surfaces without directly contacting the inner end surfaces of the pair of outer rings 13, 13. For this purpose, the same number of concave holes 30, 30 are formed at positions where the outer rings 13, 13 are aligned with each other at a plurality of circumferentially equidistant positions on the inner end surfaces of the outer rings 13, 13. Then, with the inner end surfaces of the inner rings 15a and 15a being in contact with each other, the dimensions of the respective parts are regulated so that a slight gap in the axial direction is formed between the inner end surfaces of the outer rings 13 and 13. ing. In a state where the pair of ball bearings 10a and 10a are combined, the other half of the coil spring 29 in which each half is disposed in each concave hole 30 of one of the outer rings 13, 13. Is made to enter into each concave hole 30 provided in the other outer ring 13. Then, both ends of each coil spring 29 are elastically pressed against the bottom surfaces of the respective recessed holes 30, 30. With this configuration, a predetermined constant pressure preload is applied to the balls 11 and 11 of the ball bearings 10a and 10a. The dimensions of the coil springs 29 in the free state and the spring constant are made equal to each other. In FIG. 5, these coil springs 29 are shown in a simplified manner.

In the case of this embodiment as well, generation of vibration and noise can be suppressed, and the ball bearing 10a, which has a large diameter and is ultra-thin, due to a temperature rise during rotation. It is possible to prevent the preset preload from fluctuating excessively despite the fact that the constituent members 10a are likely to thermally expand. For this reason, good bearing performance can be stably maintained.
Since other configurations and operations are the same as those of the first embodiment shown in FIGS. 1 to 3 described above, the same parts are denoted by the same reference numerals, and redundant description is omitted.

  Next, FIG. 6 shows Embodiment 4 of the present invention corresponding to claims 4-6. In the case of the present embodiment, the inner ring 31 has a total axial length that is the same as that of the first embodiment shown in FIGS. 1 to 3 described above, in which the pair of inner rings 15a and 15a are integrally combined. It is supposed to be bigger. That is, in the case of the ball bearing device 12d that is the rolling bearing device for the computer tomography apparatus of this embodiment, the pair of outer rings 13, 13 and the portions near both ends with respect to the inner peripheral surface of each of the outer rings 13, 13 are provided. And one inner ring 31 having a monolithic structure facing each other in the radial direction. The outer rings 13 and 13 have the same shape as the outer rings 13 and 13 constituting the first embodiment shown in FIGS. A pair of inner ring raceways 17, 17 are formed on the outer peripheral surface of the inner ring 31 at portions facing the outer ring raceways 18, 18. A plurality of balls 11, 11 are provided between the inner ring raceways 17, 17 and the outer ring raceways 18, 18 so as to roll freely. These balls 11 and 11 are rotatably held in pockets 20a and 20a provided in the cages 19a and 19a. In the case of the illustrated example, a synthetic resin crown-shaped cage is used as each of these cages 19a, 19a in order to ensure good assembling workability of the balls 11, 11.

  Further, an outer ring spacer 32 as shown in FIGS. 7 to 8 is provided between the inner end surfaces of the outer rings 13, 13 facing each other. The outer ring spacer 32 is formed with circular through holes 33 and 33 at a plurality of circumferentially equidistant positions on the same circumference. A plurality of coil springs 29 and 29, each of which is an elastic body, are loosely inserted into the through holes 33 and 33, respectively. The axial dimensions of the coil springs 29 and 29 in the free state are larger than the overall axial length of the outer ring spacer 32. And while providing the said outer ring | wheel spacer 32 between the inner end surfaces of each said outer ring | wheel 13,13, the both-ends edge of the coil springs 29 and 29 inserted in each through-hole 33,33 of this outer ring | wheel spacer 32 is said to be said. The outer rings 13 and 13 are elastically pressed against the inner end surfaces. With this configuration, a predetermined constant pressure preload is applied to each of the balls 11 and 11. 6 and 7, the coil springs 29 and 29 are shown in a simplified manner. Further, the shape and elastic constant of each of the coil springs 29 and 29 are equal to each other.

In the case of the present embodiment configured as described above, the generation of vibration and noise can be suppressed, and the ball bearing has a large diameter and an ultra-thin wall, resulting in a temperature rise during rotation. Although the constituent members of the device 12d are likely to thermally expand, it is possible to prevent the set preload from fluctuating excessively. For this reason, good bearing performance can be stably maintained.
Other configurations and operations are the same as those in the first embodiment shown in FIGS.

  Next, FIG. 9 shows Embodiment 5 of the present invention, which also corresponds to claims 4 to 6. In the case of the ball bearing device 12e, which is a rolling bearing device for a computed tomography apparatus of the present embodiment, unlike the case of the embodiment 4 shown in FIGS. It is provided not on the side but on the inner ring 15b, 15b side. That is, the ball bearing device 12e includes a pair of inner rings 15b and 15b and a single outer ring 34 having an integral structure in which the portions near both ends of the inner rings 15b and 15b are radially opposed to the outer peripheral surface of each of the inner rings 15b and 15b. Is provided. Angular inner ring raceways 17a and 17a are formed on the outer peripheral surfaces of the inner rings 15b and 15b. A pair of outer ring raceways 18a and 18a, each of which is of an angular type, are formed on the inner peripheral surface of the outer ring 34 at portions facing the inner ring raceways 17a and 17a. In addition, shoulders 14 and 14 are provided on the inner peripheral surfaces of both ends of the outer ring 34, and shoulders 35 and 35 are provided on the outer peripheral surfaces of the inner ends 15b and 15b opposite to each other. A plurality of balls 11, 11 are provided so as to roll freely between the outer ring raceways 18a, 18a and the inner ring raceways 17a, 17a.

Further, an inner ring spacer 36 is provided between the inner end surfaces of the inner rings 15b, 15b, and coil springs 29 are respectively inserted into through holes 33 provided at a plurality of circumferentially spaced positions in the inner ring spacer 36. Inserting. That is, the inner ring spacer 36 has the same configuration as the outer ring spacer 32 constituting the fourth embodiment shown in FIGS. And while providing the said inner ring spacer 36 between the inner end surfaces of each said inner ring | wheel 15b, 15b, the both ends edge of the coil spring 29 inserted in each through-hole 33 of this inner ring | wheel spacer 36 is said each inner ring 15b, It is elastically pressed against the inner end face of 15b. With this configuration, a predetermined constant pressure preload is applied to each of the balls 11 and 11.
Since other configurations and operations are the same as those of the fourth embodiment shown in FIGS. 6 to 8 described above, the same parts are denoted by the same reference numerals, and redundant description is omitted.

Next, FIG. 10 shows Embodiment 6 of the present invention corresponding to claim 4. In the case of the ball bearing device 12f, which is a rolling bearing device for a computed tomography apparatus of the present embodiment, the pair of outer rings 13, 13 are opposed to each other with the structure of the fourth embodiment shown in FIGS. The outer ring spacer 32 and the plurality of coil springs 29 are not provided between the inner end surfaces to be provided, and an annular leaf spring 37 such as a disc spring is provided between the inner end surfaces of the outer rings 13 and 13 instead. The both ends of the leaf spring 37 in the axial direction are elastically pressed against the inner end surfaces of the outer rings 13 and 13. With this configuration, a predetermined constant pressure preload is applied to each ball 11, 11. In this embodiment, no counterbore for locking the leaf spring 37 is formed on the inner end surface of each outer ring 13, 13, but at least one of the inner end surfaces of each outer ring 13, 13 is not formed. You can also create a spot facing.
Since other configurations and operations are the same as those of the fourth embodiment shown in FIGS. 6 to 8 described above, the same parts are denoted by the same reference numerals, and redundant description is omitted.

  It should be noted that the structure of each of the above-described embodiments has an elastic member such as the leaf springs 24 and 37 and the coil spring 29 (see FIGS. 1, 5, 10 and the like) of another embodiment, and the outer ring spacer 22 as appropriate. 27, 32 (see FIGS. 1, 4, 6, etc.) and inner ring spacers 21, 28, 36 (see FIGS. 1, 4, 9, etc.) can be combined. For example, in the structure of the fifth embodiment shown in FIG. 9, the leaf spring 37 used in the sixth embodiment shown in FIG. 10 has a reduced diameter instead of the inner ring spacer 36 and the coil spring 29. Applying a predetermined constant pressure preload to each ball 11 (FIG. 9) by elastically pressing both ends of the leaf spring against the inner end surfaces of the pair of inner rings 15b and 15b (FIG. 9) using a spring. You can also.

The fragmentary sectional view which shows Example 1 of this invention. FIG. 2 is a partial cross-sectional view showing an outer ring spacer that locks a plurality of leaf springs from FIG. 1. The figure seen from the side of FIG. The fragmentary sectional view which shows Example 2 of this invention. The fragmentary sectional view which shows the same Example 3. FIG. The fragmentary sectional view which shows the same Example 4. FIG. FIG. 7 is a partial sectional view showing an outer ring spacer that supports a plurality of coil springs from FIG. 6. The figure seen from the side of FIG. The fragmentary sectional view which shows Example 5 of this invention. The fragmentary sectional view which shows the Example 6. FIG. The fragmentary sectional view which shows an example of the conventional structure of a computer tomography apparatus. The fragmentary sectional view which shows one example of the conventional structure of the rolling bearing apparatus used in the state which gave the fixed position preload to each ball | bowl.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Subject 2 Bed part 3 Inspection part 4 Support part 5 Fixed base 6 Rotating member 7 Rolling bearing 8 X-ray tube apparatus 9 Radiation detection apparatus 10, 10a, 10b Ball bearing 11 Ball 12, 12a-12f Ball bearing apparatus 13 Outer ring 14 Shoulder Part 15, 15a, 15b Inner ring 16 Clearance 17, 17a Inner ring raceway 18, 18a Outer ring raceway 19, 19a Cage 20, 20a Pocket 21 Inner ring spacer 22 Outer ring spacer 23 Annular recess 24 Leaf spring 25 Tube part 26 Gap 27 Between outer ring Seat 28 Inner ring spacer 29 Coil spring 30 Recessed hole 31 Inner ring 32 Outer ring spacer 33 Through hole 34 Outer ring 35 Shoulder 36 Inner ring spacer 37 Leaf spring

Claims (6)

  In a rolling bearing device for a computed tomography apparatus used to rotatably support a rotating member to which a radiation source and a radiation detection apparatus of a computed tomography apparatus are fixed with respect to a fixed base, a pair facing each other in the axial direction A rolling bearing device for a computer tomography apparatus, characterized in that a constant pressure preload is applied to each rolling element of each rolling bearing by providing an elastic member between the rolling bearings.   The computer tomography apparatus according to claim 1, wherein a constant pressure preload is applied to each rolling element of each of the rolling bearings by providing elastic members at a plurality of circumferentially equidistant positions between the pair of rolling bearings. Rolling bearing device.   The rolling bearing device for a computer tomography apparatus according to claim 2, wherein each elastic member is disposed in a recess or a through hole provided in a spacer disposed between a pair of rolling bearings.   In a rolling bearing device for a computed tomography apparatus used to rotatably support a rotating member that fixes a radiation source and a radiation detection apparatus of a computed tomography apparatus with respect to a fixed base, a pair of outer rings or inner rings, By providing an inner ring or outer ring having an integral structure that is radially opposed to the pair of outer rings or inner rings, and by providing an elastic member between the pair of outer rings or inner rings that are opposed to each other in the axial direction, A rolling bearing device for a computed tomography apparatus, characterized in that a constant pressure preload is applied to a rolling element.   The rolling bearing device for a computer tomography apparatus according to claim 4, wherein a constant pressure preload is applied to each rolling element by providing elastic members at a plurality of circumferentially equidistant positions between a pair of outer rings or inner rings.   The rolling bearing device for a computed tomography apparatus according to claim 5, wherein each elastic member is disposed in a recess or a through-hole provided in a spacer disposed between a pair of outer rings or inner rings.

Images