JP2006322592A - Super-thin rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent generation of abnormal noise in a super-thin rolling bearing equipped with a split type retainer. <P>SOLUTION: This super-thin rolling bearing is provided with the retainer 50 having five or more of arc shaped retainers 52 obtained by connecting resin segments 51 in an arc shape along the circumferential direction while having a space between them. By the super-thin rolling bearing, behavior of the respective arc shaped retainers 52 is stabilized, and generation of the abnormal noise can be restrained. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ultra-thin type rolling bearing.

  As shown in FIG. 1, for example, the ultra-thin type rolling bearing 10 is used in a CT scanner device 11 which is a kind of medical equipment. The CT scanner device 11 irradiates the subject 15 with X-rays generated by the X-ray tube device 12 through a wedge filter 13 for uniforming the intensity distribution and a slit 14 for limiting the intensity distribution. X-rays that have passed through the subject 15 are received by the detector 16, converted into electrical signals, and sent to a computer (not shown). Each component such as the X-ray tube device 12, the wedge filter 13, the slit 14, and the detector 16 is mounted on a substantially cylindrical rotating mount 17 that is rotatably supported via an ultra-thin rolling bearing 10. Each component rotates around the subject 15 by the rotational drive of the rotary mount 17. Projection data covering all angles at every point in the examination section of the subject 15 is obtained by rotational movement of the opposing X-ray tube device 12 and detector 16 around the subject 15 and pre-programmed from these data. A tomographic image is obtained by a reconstruction program.

  In the CT scanner device 11, the inner peripheral surface of the fixed gantry 18 is formed with a large diameter (approximately 1 m in diameter) that allows the subject 15 to enter, and the bearing between the fixed gantry 18 and the rotary gantry 17 has a diameter of On the other hand, an ultra-thin type rolling bearing 10 having a remarkably small cross section is used. As the ultra-thin type rolling bearing 10 for such a CT scanner device, a double-row angular ball bearing and a single-row four-point contact bearing are generally used.

  As shown in FIG. 2, the double-row angular ball bearing 20 uses two angular ball bearings 21 and 22 facing each other, and regulates the movement in the axial direction by adjusting the axial internal clearance or applying a preload. . As shown in FIG. 3, the single-row four-point contact bearing 30 is formed with raceways 37 and 38 formed in a valley shape with two curved surfaces 33 to 36 on the inner ring 31 and the outer ring 32, and the inner ring 31 and the outer ring 32. A plurality of balls 40 (rolling elements) held by the cage 39 are disposed between the raceway grooves 37 and 38. The single-row four-point contact bearing 30 has a simple structure because the ball 40 is firmly held between the raceway grooves 37 and 38, and the inner and outer rings 31 and 32 formed integrally are high in rigidity. A high load capacity can be obtained.

In addition, since the CT scanner device 11 has a large space with a diameter of about 1 m that secures a space for receiving the fixed base 18 and the subject 15, the ultra-thin type rolling bearing 10 for the CT scanner device 11 is divided. A cage is frequently used (Japanese Patent Laid-Open No. 2004-125088). As shown in FIG. 4A, the split cage 39 is formed by annularly connecting a plurality of arc-shaped segments 41. For example, as shown in FIG. 4B, the segment 41 is provided with a concave portion 42 and a convex portion 43 at both ends, and the concave portion 42 and the end portion 43 of the adjacent segment 41 are fitted and coupled.
JP 2004-125088 A

  The conventional split type retainer unites a plurality of arc-shaped segments in an annular shape, but the four-point contact bearing does not receive preload as in the double row angular ball bearing. There is a clearance between the rolling elements and the raceway surface. When incorporated in a CT scanner device, a portion with a large load (load zone) and a portion with a small load (non-load zone) may be generated with respect to the rolling of the rolling element due to its own weight or assembly error. Since the resistance to rolling of the rolling elements is greater in the load zone than in the non-load zone, the behavior of the cage may become unstable and abnormal noise may occur. In a machine such as a CT scanner device that requires a reduction in noise of the device itself, such abnormal noise must be suppressed as much as possible. Particularly, in the split type cage in which the segments are combined, the backlash is large by the gap between the segments.

  An ultra-thin type rolling bearing according to the present invention includes an inner ring and an outer ring each having a raceway groove formed by two curved surfaces, a plurality of rolling elements interposed between the raceway grooves of the inner ring and the outer ring, and the rolling element In an ultra-thin type rolling bearing provided with a cage in which a plurality of arc-shaped resin segments each having a pocket for holding are joined, the cage is an arc-shaped cage in which resin segments are joined in an arc shape, It is characterized by being arranged at intervals of 5 or more in the circumferential direction.

  According to this ultra-thin type rolling bearing, since the cage is provided with an arc-shaped cage in which resin segments are joined in an arc shape with a spacing of five or more in the circumferential direction, an independent circle The arc-shaped cage has a small difference in load received from the rolling elements partially. For this reason, even when the ultra-thin type rolling bearing according to the present invention is used for rotation support of the rotary base of the CT scanner device, the behavior of each cage is stabilized, so that the generation of abnormal noise can be prevented. it can.

  Hereinafter, an ultra-thin type rolling bearing according to an embodiment of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to drawing and the member and site | part which show | plays the same effect | action.

  As shown in FIG. 3, the ultra-thin type rolling bearing 30 holds an inner ring 31, an outer ring 32, balls 40 as a plurality of rolling elements interposed between the inner ring 31 and the outer ring 32, and the rolling elements 40. The retainer 50 is provided.

  The inner ring 31 and the outer ring 32 are provided with raceway grooves 37 and 38 formed in a valley shape by two curved surfaces 33 to 36, respectively, and when the inner ring 31 and the outer ring 32 are pressed in the radial direction, the ball 40 is moved into the inner and outer rings 31. , 32 in contact with the raceway grooves 37, 38 at four points. The ball 40 rolls in two-point contact with the raceways 37 and 38 of the inner and outer rings 31 and 32 in a normal use state.

  As shown in FIG. 5, the cage 50 is configured by arranging five or more arc-shaped cages 52 in which resin-made segments 51 are joined in an arc shape at intervals in the circumferential direction. Although illustration is omitted, each arc-shaped cage 52 has pockets for storing 10 to 35 balls, and the balls are stored in the respective pockets. In this embodiment, one arc-shaped cage 52 has pockets for accommodating 18 to 21 balls, and the balls are accommodated in the respective pockets.

  This ultra-thin type rolling bearing 30 has a diameter of about 1 m as a whole, and is disposed between the rotary mount 17 and the fixed mount 18 of the CT scanner device 11 as shown in FIG. The outer ring 32 is attached to the rotary mount 17 and attached to the fixed mount 18.

  According to this ultra-thin type rolling bearing 30, as shown in FIG. 5, cages 52 that are divided into five in the circumferential direction and are respectively joined with resin segments 51 in an arc shape are arranged at intervals. Therefore, when comparing each part of the independent arc-shaped cage 52, the difference in load received from the ball 40 is small. For this reason, the behavior of each arcuate cage 52 is stabilized, and it is possible to prevent the generation of abnormal noise.

  In order to confirm the effect of the bearing according to the above embodiment, the present inventors have divided the cage 61 divided at one place in the circumferential direction and three places as shown in FIGS. A comparative test was conducted using the cage 62 divided at 5 locations. In this test, as shown in FIG. 3, the outer ring 32 of the ultra-thin type rolling bearing 30 was fixed to a fixing member 65 with spacers 64 sandwiched between six portions that were even in the circumferential direction. Then, the thickness of the spacer 64 in one part was set to 9.6 mm, and the other part was set to 10 mm to form a load zone in which the outer ring 32 was distorted to partially increase the resistance to rolling of the ball 40.

  As a result, the behavior of the cage is stabilized in proportion to the number of cages divided in the circumferential direction, compared with the cage 61 divided at one circumferential direction and the cage 62 divided at three locations. In the divided cage 50, the behavior of each arc-shaped cage 52 is stabilized, and the generation of abnormal noise can be suppressed to a small level.

  Although the ultra-thin type rolling bearing according to the embodiment of the present invention has been described above, the ultra-thin type rolling bearing according to the present invention is not limited to this.

  If the cage is divided into five or more in the circumferential direction, the behavior of each arc-shaped cage is stabilized, and the generation of abnormal noise can be suppressed low. For example, the cage may be divided into six or eight.

The figure which shows CT scanner apparatus. The figure which shows a double row angular contact ball bearing. The figure which shows a single row 4-point contact bearing. (A) is a figure which shows a split type holder, (b) is a figure which shows the coupling | bonding structure of the segment of a split type holder. The figure which shows the holder | retainer which cut | disconnected 5 places of the circumferential direction. (A) shows the holder | retainer which divided | segmented one place of the circumferential direction, (b) is a figure which shows the holder | retainer divided | segmented three places of the circumferential direction.

Explanation of symbols

50 Cage 51 Resin Segment 52 Arc Cage

Claims (3)

Inner and outer rings having raceway grooves formed in a valley shape with two curved surfaces, a plurality of rolling elements interposed between the raceway grooves of the inner ring and the outer ring, and a plurality of arc shapes having pockets for holding the rolling elements In an ultra-thin type rolling bearing equipped with a cage joined with resin segments of
The retainer is an ultra-thin type rolling bearing in which arc-shaped cages in which resin segments are joined in an arc shape are arranged at intervals of five or more in the circumferential direction.   2. The ultra-thin type rolling bearing according to claim 1, wherein each of the arc-shaped cages holds 10 to 35 rolling elements.   The ultra-thin type rolling bearing according to claim 1, which is mounted between a rotary mount and a fixed mount of the CT scanner device.

Images