JP2017125618A - Double-row rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a double-row rolling bearing which can suppress the misalignment of a pair of bearing rings which form an outer member or an inner member, and is high in quietness and rigidity, low in vibration, easy in manufacturing, and low in cost.SOLUTION: A double-row roller bearing 1 is composed of: an outer member 2 having two raceway surfaces 6 and 6 at an internal periphery; an inner member 3 provided inside the outer member 2, and having two raceway surfaces 7 and 7 at an external periphery; two rows of rolling bodies 4 and 4 which are assembled between the raceway surfaces 6 and 6 of the outer member 2, and the raceway surfaces 7 and 7 of the inner member 3; and a cage 5 for holding the rolling bodies 4. One of the outer member 2 and the inner member 3 is formed of a pair of bearing rings 3a and 3b, and both the bearing rings 3a and 3b are fastened to each other with a fixing bolt 16. Positioning holes 13a and 13b are formed at the pair of bearing rings 3a and 3b, and the misalignment of the pair of bearing rings 3a and 3b in a radial direction is suppressed by inserting positioning members 14 and 14' into the positioning holes 13 and 13b.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a double row rolling bearing used in various fields including industrial machines, and more particularly to an ultra-thin type double row rolling bearing used in medical equipment including a CT scanner device.

  FIG. 5 shows an example of a CT scanner device 100 which is a kind of medical equipment. The CT scanner apparatus 100 is an apparatus that diagnoses and analyzes pathological symptoms by irradiating X-rays or the like. The CT scanner device 100 includes an inspection unit 101 provided with an opening 101A, and a bed unit 102 on which an object to be inspected 110 such as a human body is placed and movable within the opening 101A of the inspection unit 101. The inspection unit 101 is provided with a ring-shaped rotating body 105 (gantry) in which an X-ray irradiation device 103 and a detection unit 104 are arranged to face each other in the diameter direction. The rotating body 105 is rotatably supported by a cylindrical fixed portion 106 via a bearing 51.

  In the CT scanner device 100, in a state where X-rays are irradiated from the X-ray irradiation device 103, the rotating body 105 is rotated around the bed portion 102, and X-rays transmitted through the inspection object 110 are detected by the detection unit 104. By doing so, a cross-sectional image of the inspection object 110 can be obtained.

  In the CT scanner device 100, the opening 101A of the inspection unit 101 is formed to have a size (approximately 1 m in diameter) that allows the inspection object 110 to pass through, and the CT scanner device 100 itself can be miniaturized. In addition, it is necessary to reduce the space of the rotation support portion 107 in which the bearing 51 is disposed. Therefore, the bearing 51 is a so-called ultra-thin type double row rolling bearing in which the ball diameter is remarkably small with respect to the pitch circle diameter of the ball. Here, the ultra-thin type rolling bearing has an inner diameter of 650 mm or more, and an ultra-thin type large-size rolling whose ratio Db / PCD between the rolling element diameter Db and the rolling element pitch circle diameter PCD is 0.03 or less. A bearing.

  Patent Document 1 describes an ultra-thin type double row rolling bearing having a structure in which an inner member is composed of a pair of race rings and these race rings are fastened in a concentric state by an inlay. This double row rolling bearing is shown in FIG. The double row rolling bearing 51 mainly includes an outer member 52, an inner member 53, a rolling element 54, and a cage 55. A double-row angular contact ball bearing in which balls 54 as rolling elements are arranged in two rows, and is incorporated between two rows of raceway surfaces 56 and 56 of the outer member 52 and two rows of raceway surfaces 57 and 57 of the inner member 53. The balls 54 and 54 are in contact with each other at a contact angle, and have a back surface arrangement suitable for supporting a moment load.

  The inner member 53 includes a pair of race rings 53a and 53b. The race ring 53a has a screw hole 58a, and the race ring 53b has a fitting insertion hole 58b. The race rings 53 a and 53 b are fastened by bolts 59. At that time, misalignment between the race rings 53a and 53b is prevented by the inlay structure by the convex portion 60a formed on the race ring 53a and the recess 60b formed on the race ring 53b. A bolt 59 is tightened to pressurize the race 53b toward the race 53a, so that a preload (minus clearance) is applied to the bearing.

JP 2006-266458 A

  However, the inlay structure of the double row rolling bearing 51 described in Patent Document 1 has been found to have the following problems. That is, in the inlay structure including the convex portion 60a formed on the raceway ring 53a and the concave portion 60b formed on the raceway ring 53b, it is necessary to process the convex portion 60a and the concave portion 60b with a high degree of accuracy until a small fit. However, since the convex part 60a and the concave part 60b are formed in the thin and large-diameter race rings 53a and 53b, it is difficult to process with high accuracy. In addition, there is a problem that the manufacturing cost increases significantly if high precision processing is performed.

  On the other hand, it has also been found that if the allowable dimension range of the fitting clearance between the convex portions 60a and the concave portions 60b is relaxed in order to reduce the manufacturing cost, the following problems occur. For example, in the CT scanner device 100 shown in FIG. 5, as described above, the inspection unit 101 has the ring-shaped rotating body 105 (X-ray irradiation device 103 and detection unit 104 facing each other in the diameter direction) ( Gantry) is provided. Since the rotating body 105 is rotatably supported by the cylindrical fixed portion 106 via the bearing 51 in a state close to a cantilever, a large moment load is applied to the bearing 51. It is in a severe usage environment where it rotates at a high speed of 120 rpm or higher.

  In addition, medical devices require consideration so as not to give anxiety or fear to the patient undergoing the examination. In particular, in the case of a CT scanner device, the patient himself / herself is located at a tunnel entrance called a gantry. Therefore, mechanical operation sound and electrical excitation sound are disliked. As a result, low noise, low vibration, and high rigidity are required for the bearing, and since the CT scanner device is an expensive medical device, excellent durability is desired, and the bearing has a long life. Required.

  Since the bearing is in use as described above, if the allowable dimension range of the fitting clearance between the convex portion 60a and the concave portion 60b is expanded, the misalignment of the pair of race rings 53a and 53b cannot be sufficiently suppressed, and the bearing It is difficult to set the appropriate internal preload (minus clearance) or the smallest possible clearance with the two right and left rows of rings, and there is a concern about problems such as preload loss during the moment load action. It was found that there were problems with vibration and high rigidity.

  In view of the above problems, the present invention can suppress the misalignment of a pair of races that form an outer member or an inner member, has low noise, low vibration, and high rigidity, and is easy to manufacture and low cost. An object of the present invention is to provide a double row rolling bearing.

  As a result of various studies to achieve the above-described object, the present inventors have a new idea of suppressing the misalignment of the pair of track rings by the positioning member, apart from the fixing bolts of the pair of track rings, The present invention has been reached.

As technical means for achieving the above-mentioned object, the present invention provides an outer member having two raceway surfaces on the inner periphery, and an inner member disposed inside the outer member and having two track surfaces on the outer periphery. A rolling member incorporated between a raceway surface of the outer member and a raceway surface of the outer member, and a cage that holds the rolling body, and the outer member and the inner member. In a double row rolling bearing in which either one of the members is formed by a pair of race rings and both race rings are fastened by fixing bolts,
A positioning hole is provided in the pair of track rings, and a positioning member is fitted into the positioning hole to suppress radial misalignment of the pair of track rings.

  With the above configuration, it is possible to suppress the radial misalignment of the pair of races, and to realize a low-noise, low-vibration, high-rigidity, easy-to-manufacture and low-cost double-row rolling bearing.

  In the above-described configuration, it is desirable that the end surfaces of the pair of race rings in contact with each other be flat. In this case, since the spigot structure can be abolished, manufacturing is easier and cost reduction can be achieved.

  Specifically, it is desirable to use the pair of raceways as inner members. In this case, it is possible to easily set the bearing clearance by arranging the double row rolling bearings in a back arrangement advantageous for moment load and abutting the end faces of the pair of race rings.

  By using a reamer bolt or positioning pin as the positioning member, a commercially available product can be used as appropriate, which is preferable in terms of quality and cost.

  The number of the positioning holes can be two or more. If there are at least two positioning holes, the positions in the vertical and horizontal directions and the rotational direction can be determined. In this case, it is preferable that the pitch angle between the positioning holes is an angle that is not a multiple of the pitch angle between the rolling elements. The reason is that, after the positioning member is driven in, the fitting between the positioning member and the positioning hole may be an interference fit, and thus there is a possibility that the number of positioning holes on the raceway surface may be distorted. Since this distortion can induce and amplify periodic vibrations in relation to the number of rolling elements, the problem can be solved by setting the pitch angle between the positioning holes to an angle that is not a multiple of the pitch angle between the rolling elements. Can be resolved.

  N ≧ W / [σ × (0.6 to 0.7) × A] where N is the number of the above reamer bolts, W is the load shear load, W is the allowable tensile stress σ of the bolt, and A is the sectional area A of the bolt. Set to satisfy the relationship. Thereby, sufficient intensity | strength with respect to a shear load is securable.

  By making the fitting clearance between the positioning member and the positioning hole smaller than the fitting clearance between the fixing bolt and the bolt fitting insertion hole, misalignment of the pair of race rings can be effectively suppressed.

  By using the double row rolling bearing as the back surface arrangement of the angular ball bearing, low noise, low vibration, and high rigidity can be achieved at high speed. This double row rolling bearing is suitable for a CT scanner device.

  According to the present invention, it is possible to realize a double-row rolling bearing that can suppress misalignment of a pair of races, has low noise, low vibration, and high rigidity, is easy to manufacture, and is low in cost.

It is a longitudinal cross-sectional view of the double row rolling bearing which concerns on the 1st Embodiment of this invention. It is a longitudinal cross-sectional view in the position where the circumferential direction of said double row rolling bearing differs. It is a longitudinal cross-sectional view in the position where the circumferential direction of said double row rolling bearing differs. It is a front view of said double row rolling bearing. It is a schematic diagram showing a CT scanner device. It is a longitudinal cross-sectional view of the double row rolling bearing which concerns on the 2nd Embodiment of this invention. It is a longitudinal cross-sectional view of the double row rolling bearing which concerns on the 3rd Embodiment of this invention. It is a longitudinal cross-sectional view of the double row rolling bearing which concerns on the 4th Embodiment of this invention. It is a longitudinal cross-sectional view of the conventional double row rolling bearing.

  Embodiments of the present invention will be described below with reference to the drawings.

  A double row rolling bearing according to a first embodiment of the present invention will be described with reference to FIGS.

  1 to 3 are longitudinal sectional views of the double-row rolling bearing of the present embodiment, and FIG. 4 is a front view partially including a transverse section. 1 to 3 are different in circumferential position, FIG. 1 is a longitudinal section taken along line EE in FIG. 4, FIG. 2 is a longitudinal section taken along line FF in FIG. 4, and FIG. A longitudinal section at line G is shown. As an outline of these longitudinal sections, in FIG. 4, the positions where the mounting holes for mounting the double row rolling bearing 1 to the equipment to be used are provided in the EE cross section, and there are eight positions in the circumferential direction. The positions where the positioning holes for suppressing the misalignment of the pair of race rings are shown in the FF cross section, and there are three positions in the circumferential direction, and the positions where the bolt insertion holes for fastening the pair of race rings are provided. Eight locations in the circumferential direction are shown in the GG section. Details will be described later.

  As shown in FIG. 1, the double row rolling bearing 1 mainly includes an outer member 2, an inner member 3, a ball 4 as a rolling element, and a cage 5. Both the outer member 2 and the inner member 3 are ring-shaped and arranged concentrically. The inner member 3 includes a pair of race rings 3a and 3b. End surfaces 10a and 10b of the race rings 3a and 3b that are in contact with each other are formed as flat surfaces and do not have an inlay structure. The outer member 2 is formed with two rows of raceway surfaces 6 and 6 on the inner circumference, and the outer circumference of each of the pair of raceways 3a and 3b forming the inner member 2 is on the raceway surface of the outer member 2. 6 and 6 are formed on the raceway surfaces 7 and 7 facing each other. Two rows of balls 4 are incorporated between the raceway surfaces 6 and 6 of the outer member 2 and the raceway surfaces 7 and 7 of the inner member 3. The cage 5 is disposed between the outer member 2 and the inner member 3, and the balls 4 in each row are held at predetermined intervals in the circumferential direction.

  The double row rolling bearing 1 of the present embodiment is a double row angular ball bearing in which balls 4 are arranged in two rows. The bearing portions in both rows are arranged in the back, and the intersection of the lines of action of the rolling element load is outside the pitch circle of the balls 4. The ball 4 and the raceway surfaces 6 and 7 are in contact with each other with a contact angle α, and the contact angle α is, for example, about 30 °. By making the pair of race rings 3a, 3b into the inner member 3, the double-row rolling bearing 1 is arranged in a back arrangement advantageous for moment load, and the end faces 10a, 10b of the pair of race rings 3a, 3b are abutted, Bearing clearance (preload or minute clearance) can be set easily. This double row rolling bearing 1 is an ultra-thin type double row rolling bearing in which the ratio Db / PCD of the diameter Db of the ball 4 to the pitch circle diameter PCD is 0.03 or less.

  The bearing rings 3a and 3b are formed with a shoulder drop portion 12 having a small outer periphery. The shoulder drop portion 12 forms a labyrinth in cooperation with the inner diameter end portion of the seal member 11 attached to the inner periphery of the outer member 2. By making the outer diameters of the shoulder drop portions 12 equal, it becomes possible to use the common seal member 11 on both sides.

  The outer member 2 is provided with a mounting hole 8 in the form of a through-hole for passing a bolt (not shown), and is fastened and fixed to the mating member of the equipment used by the bolt. In the present embodiment, as shown in FIG. 4, the attachment holes 8 are provided at eight locations at equal intervals in the circumferential direction. The race 3a of the inner member 3 is provided with a screw hole 9 that is screwed with a bolt (not shown), and is fastened and fixed to a mating member of the equipment used by the bolt. Similar to the outer member 2, as shown in FIG. 4, the screw holes 9 are provided at eight locations at equal intervals in the circumferential direction. However, it is needless to say that the mounting holes 8 and the screw holes 9 are not limited to eight places, and may be provided in a suitable number of places. Moreover, it is not restricted to an equal interval, You may provide at an appropriate unequal interval.

  In a normal use state in which the inner diameter and outer diameter of the bearing are fitted to the shaft or the housing, the pair of race rings 3a and 3b forming the inner member 3 are fitted to the shaft to prevent radial misalignment. However, as described above, the double-row rolling bearing 1 of the present embodiment is fastened and fixed to the mating member of the equipment by bolts at the bearing width surface, so that the two rows of raceways 3a and 3b have a relative diameter. This is a use state in which the effect is great when a moment load is applied, and problems such as preload loss are concerned.

  The double-row rolling bearing of the present embodiment is used in the above-described state, and the configuration for suppressing the misalignment of the pair of race rings 3a and 3b forming the inner member 3 which is a feature thereof is shown in FIG. Based on As described above, the inner member 3 includes a pair of race rings 3a and 3b, and the end faces 10a and 10b of the race rings 3a and 3b that are in contact with each other are formed as flat surfaces. The race rings 3a and 3b are provided with reamer holes 13a and 13b as positioning holes in the form of through holes into which reamer bolts 14 as positioning members are inserted. In this embodiment, as shown in FIG. 4, the reamer holes 13a and 13b are provided at three locations at equal intervals in the circumferential direction. However, the reamer holes 13a and 13b are not limited to three places or at equal intervals, and can be set at an appropriate number and at appropriate intervals.

Specifically, if there are at least two fitting portions of the reamer holes 13a and 13b and the reamer bolt 14, the positions in the vertical and horizontal directions and the rotational direction can be determined. However, since the shear load is received, the shear load to be applied is determined. It is desirable to decide in consideration. In general, since the bolt shear stress is 60 to 70% of the tensile stress, the number of reamer bolts 14 is N, the load shear load is W, the allowable tensile stress of the bolt 14 is σ, and the sectional area of the bolt 14 is A. The number of reamer bolts 14 is obtained by the following equation.
N ≧ W / [σ × (0.6 to 0.7) × A]
Therefore, in the double row rolling bearing 1 of this embodiment, it is set so as to satisfy the relationship of N ≧ W / [σ × (0.6 to 0.7) × A]. Thereby, sufficient intensity | strength with respect to a shear load is securable.

  The reamer bolt 41 has an outer diameter portion finished with high accuracy, and can regulate the clearance between the reamer holes 13a and 13b of the race rings 3a and 3b when fitted. In this fitting, the clearance between the outer diameter of the fixing bolt 16 (see FIG. 3) and the inner diameter of the fitting insertion hole 17b is B, and the outer diameter of the reamer bolt 14 and the inner diameter of the reamer holes 13a and 13b. When the clearance between them is C, the relationship of clearance B> clearance C is necessary. The reamer bolt 14 and the reamer holes 13a and 13b are ideally combined (in-kind alignment) if possible.

  Further, when the reamer bolts 14 are inserted into the reamer holes 13a and 13b, there is a possibility that an interference fit will occur. At this time, there is a possibility that a distortion corresponding to the number of the reamer bolts 14 occurs on the raceway surface 7. Since this strain may induce and amplify periodic vibrations in relation to the number of rolling elements, in order to avoid this, the pitch angle between the reamer holes 13a and 13a and between the rolling elements 13b and 13b is set between the rolling elements. It is desirable to set an angle that is not a multiple of the pitch angle. In order to clarify this relationship, a partial cross-sectional view is added to FIG. 4, which is a front view of the double row rolling bearing 1, to show the arrangement of the rolling elements 4.

  Here, as shown in FIG. 4, the pitch angle between the positioning holes refers to the center of each of the reamer holes 13 a, 13 a and 13 b, 13 b serving as the positioning holes adjacent to the circumferential direction and the axis O of the rolling bearing 1. Is an angle β formed by two straight lines H and I. The pitch angle between the rolling elements refers to an angle θ formed by two straight lines J and K connecting the centers of the rolling elements 4 and 4 adjacent to each other in the circumferential direction and the axis O of the rolling bearing 1. That is, it is desirable to set the pitch angle β between reamer holes as positioning holes to an angle that is not a multiple of the pitch angle θ between the rolling elements. The same applies to the pitch angle between the remaining reamer holes 13a, 13a and 13b, 13b. The same meaning is used in the present specification and claims.

  Specifically, in the double row rolling bearing 1 of the present embodiment, since the number of balls 4 incorporated in each row is 110, the pitch angle θ between the rolling elements is 3.27 °. Become. On the other hand, since the reamer holes 13a and 13b are arranged at three positions at equal intervals in the circumferential direction, the pitch angle β between the reamer holes is 120 °. Therefore, since the pitch angle β between the positioning holes is set to an angle that is not a multiple of the pitch angle θ between the rolling elements, it is possible to prevent the periodic vibration related to the number of rolling elements from being induced and amplified.

  As described above, the reamer holes 13a and 13b and the reamer bolt 14 are set. Reamer bolts 14 are fitted into the reamer holes 13 a and 13 b, and a pair of race rings 3 a and 3 b forming the inner member 3 are fastened and fixed with nuts 15. Thereby, the radial misalignment of the races 3a and 3b can be suppressed. As the reamer bolt 14, a commercially available product can be used as appropriate, which is preferable in terms of quality and cost.

  Next, the pair of race rings 3a and 3b are fastened with fixing bolts. This state will be described with reference to FIG. Of the pair of race rings 3a and 3b forming the inner member 3, the race ring 3a is provided with a screw hole 17a, and the race ring 3b is provided with a bolt fitting hole 17b. As described above, the clearance B between the outer diameter of the fixing bolt 16 and the inner diameter of the fitting insertion hole 17b is set larger than the clearance C between the inner diameters of the reamer holes 13a and 13b.

  As shown in FIG. 4, the screw holes 17a and the fitting insertion holes 17b are provided at eight positions at equal intervals in the circumferential direction. However, the screw holes 17a and the fitting insertion holes 17b are not limited to eight places at equal intervals, and can be set at an appropriate number and at appropriate intervals.

  As shown in FIG. 3, the fixing bolt 16 is passed through the fitting insertion hole 17b and screwed into the screw hole 17a, and is screwed and tightened until the end faces 10a and 10b of the race rings 3a and 3b come into contact. As described above, in the double row rolling bearing 1 of the present embodiment, since the reamer holes 13a and 13b and the reamer bolt 14 are provided, the misalignment of the pair of race rings 3a and 3b is suppressed. When screwed and tightened until the end faces 10a and 10b come into contact with each other, an appropriate preload (for example, about -20 to 0 μm) or a small clearance (for example, about 0 to 20 μm) by the fixed position preload has two rows of left and right race rings 3a 3b can be obtained uniformly and stable bearing performance can be obtained. Moreover, since the double row rolling bearing 1 of this embodiment does not have an inlay structure, it is easy to manufacture and can realize low cost.

  FIG. 5 shows a state in which the double-row rolling bearing 1 of this embodiment is used in the CT scanner device 100. The double row rolling bearing 1 is assembled between the fixed portion 106 of the CT scanner device 100 and the rotating body 105, and is fastened and fixed to the fixed portion 106 through bolts (not shown) in the mounting holes 8 of the outer member 2 shown in FIG. A bolt (not shown) is screwed into the screw hole 9 of the side member 3 to be fastened and fixed to the rotating body 105. Accordingly, the rotating body 105 is rotatably supported by the fixed portion 106 via the double row rolling bearing 1. Since the rotating body 105 is equipped with an imaging device such as the X-ray irradiation device 103 and the detection unit 104, a large moment load is applied to the rolling bearing 1, and it is used at a high-speed rotation of 120 rpm or more in such a load state. Is done.

  Although the use environment is severe as described above, the double row rolling bearing 1 according to the present embodiment is capable of suppressing the misalignment of the pair of race rings 3a and 3b, and having an appropriate preload or a minute clearance having two rows on the left and right sides. Since it can be obtained uniformly with a ring, it is possible to obtain stable bearing performance with high speed rotation, low noise, low vibration and high rigidity. For this reason, the CT scanner device 1 provides remarkable effects such as reducing the burden on the patient by shortening the imaging time, reducing the amount of exposure by imaging, and reducing the patient's anxiety and fear due to low noise.

  Next, a double row rolling bearing according to a second embodiment of the present invention will be described with reference to FIG. In this double row rolling bearing 1, the configuration in which the reamer bolt 14 is directly screwed into the raceway ring 3a is different from that in the first embodiment, and the other configurations are the same as those in the first embodiment. Specifically, in this embodiment, only the cross section provided with the reamer hole for suppressing the misalignment between the race rings of the inner member is shown in FIG. 6, but the mounting hole for attaching the bearing to the equipment to be used is provided. The cross section, the cross section provided with fitting insertion holes for fastening both the left and right race rings, and the front of the bearing are the same as those in FIGS. 1, 3 and 4 of the first embodiment. Parts having the same functions as those of the first embodiment are denoted by the same reference numerals, and the main points will be described.

  In the double row rolling bearing 1 of the present embodiment, the race ring 3a is provided with a reamer hole 13a and a screw hole 13c concentrically therewith, and the race ring 3b has the same reamer hole 13b as in the first embodiment. Is provided. The reamer bolt 14 is inserted into the reamer holes 13a and 13b and screwed into the screw holes 13c to fasten and fix the races 3a and 3b. Thereby, the misalignment of the pair of race rings 3a and 3b forming the inner member 3 is suppressed. In this embodiment, since the nut of the reamer bolt 14 and the counterbore process for the reamer bolt 14 can be omitted, the number of parts and the processing can be reduced. Regarding the other points, the contents described in the first embodiment are all applied, and the description is omitted.

  A double-row rolling bearing according to a third embodiment of the present invention will be described with reference to FIG. In this double row rolling bearing 1, the configuration in which the positioning member is a positioning pin is different from that of the first embodiment, and other configurations are the same as those of the first embodiment. Also in the present embodiment, FIG. 7 shows only a cross section provided with a reamer hole for restraining misalignment between the inner and outer races. The cross section provided with the fitting insertion hole for fastening both the bearing rings and the front of the bearing are the same as those in FIGS. 1, 3 and 4 of the first embodiment. Parts having the same functions as those of the first embodiment are denoted by the same reference numerals, and the main points will be described.

  In the double-row rolling bearing 1 of the present embodiment, the positioning pins 14 'are fitted into the reamer holes 13a and 13b of the race rings 3a and 3b to suppress misalignment of the race rings 3a and 3b. If the positioning pin 14 'and the reamer holes 13a and 13b are fitted to each other with an appropriate interference fit, positioning pin fixing means is unnecessary. Since the positioning pin 14 'is used in the present embodiment, machining of the spot facing portions of the race rings 3a and 3b can be omitted, and a commercially available product can be adopted as the positioning pin 14' as appropriate, in terms of quality and cost. Is preferable. Regarding the other points, the reamer bolt in the first embodiment described above is replaced with the positioning pin, and all the contents described in the first embodiment are applied mutatis mutandis, and the description is omitted.

  A double-row rolling bearing according to a fourth embodiment of the present invention will be described with reference to FIG. In this double row rolling bearing, a reamer bolt is applied to an inlay structure race. Also in this embodiment, FIG. 8 shows only a cross section provided with a reamer hole for suppressing the misalignment between the race rings of the inner member. About the structure which provided the fitting insertion hole which fastens both track rings, and the front surface of a bearing, the main point is the same as FIG. 1, 3 and FIG. 4 of 1st Embodiment.

  In the present embodiment shown in FIG. 8, the reamer bolt 14 and the reamer are also provided when the allowable dimension range of the fitting clearance is relaxed in order to reduce the processing cost of the projections 18a and the recesses 18b of the inlay structure of the races 3a and 3b. With the addition of the holes 13a and 13b, misalignment of the races 3a and 3b can be suppressed with high accuracy. As a different point from the first embodiment, the outer member 2 has a flange portion and a lubricant supply passage 19. Parts having the same functions as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In summary, each of the embodiments described above includes a positioning member (for example, a reamer bolt or a positioning pin) for positioning the pair of races in the radial direction separately from the bolts for fixing the races. This is a double-row rolling bearing that regulates radial misalignment. Since the center misalignment of the pair of race rings is suppressed, when screwed in and tightened until the end faces of the race rings come into contact, appropriate preload or minute clearance can be obtained uniformly with two rows of race rings, so high speed rotation However, low noise, low vibration, high rigidity and stable bearing performance can be obtained.

  In each embodiment, the inner member 3 is formed by a pair of track rings 3a and 3b. However, the present invention is not limited to this, and the outer member 2 may be formed by a pair of track rings.

  In each embodiment, although the ball | bowl 4 was illustrated as a rolling element, it is not restricted to this, A tapered roller or a cylindrical roller can be used.

  The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the spirit of the present invention. All equivalents and equivalents of the claims, and all modifications within the scope of the claims are embraced by the claims.

DESCRIPTION OF SYMBOLS 1 Double row rolling bearing 2 Outer member 3 Inner member 3a Track ring 3b Track ring 4 Rolling body 5 Cage 6 Track surface 7 Track surface 8 Mounting hole 9 Screw hole 10a End surface 10b End surface 13a Positioning hole 13b Positioning hole 14 Reamer bolt 14 'Positioning pin 16 Fixing bolt 17a Screw hole 17b Insertion hole 100 CT scanner device B Clearance C Clearance O Shaft center α Contact angle β Pitch angle between positioning holes θ Pitch angle of rolling elements

  The present invention relates to a double row rolling bearing used in various fields including industrial machines, and more particularly to an ultra-thin type double row rolling bearing used in medical equipment including a CT scanner device.

  FIG. 5 shows an example of a CT scanner device 100 which is a kind of medical equipment. The CT scanner apparatus 100 is an apparatus that diagnoses and analyzes pathological symptoms by irradiating X-rays or the like. The CT scanner device 100 includes an inspection unit 101 provided with an opening 101A, and a bed unit 102 on which an object to be inspected 110 such as a human body is placed and movable within the opening 101A of the inspection unit 101. The inspection unit 101 is provided with a ring-shaped rotating body 105 (gantry) in which an X-ray irradiation device 103 and a detection unit 104 are arranged to face each other in the diameter direction. The rotating body 105 is rotatably supported by a cylindrical fixed portion 106 via a bearing 51.

  In the CT scanner device 100, in a state where X-rays are irradiated from the X-ray irradiation device 103, the rotating body 105 is rotated around the bed portion 102, and X-rays transmitted through the inspection object 110 are detected by the detection unit 104. By doing so, a cross-sectional image of the inspection object 110 can be obtained.

  In the CT scanner device 100, the opening 101A of the inspection unit 101 is formed to have a size (approximately 1 m in diameter) that allows the inspection object 110 to pass through, and the CT scanner device 100 itself can be miniaturized. In addition, it is necessary to reduce the space of the rotation support portion 107 in which the bearing 51 is disposed. Therefore, the bearing 51 is a so-called ultra-thin type double row rolling bearing in which the ball diameter is remarkably small with respect to the pitch circle diameter of the ball. Here, the ultra-thin type rolling bearing has an inner diameter of 650 mm or more, and an ultra-thin type large-size rolling whose ratio Db / PCD between the rolling element diameter Db and the rolling element pitch circle diameter PCD is 0.03 or less. A bearing.

  Patent Document 1 describes an ultra-thin type double row rolling bearing having a structure in which an inner member is composed of a pair of race rings and these race rings are fastened in a concentric state by an inlay. This double row rolling bearing is shown in FIG. The double row rolling bearing 51 mainly includes an outer member 52, an inner member 53, a rolling element 54, and a cage 55. A double-row angular contact ball bearing in which balls 54 as rolling elements are arranged in two rows, and is incorporated between two rows of raceway surfaces 56 and 56 of the outer member 52 and two rows of raceway surfaces 57 and 57 of the inner member 53. The balls 54 and 54 are in contact with each other at a contact angle, and have a back surface arrangement suitable for supporting a moment load.

  The inner member 53 includes a pair of race rings 53a and 53b. The race ring 53a has a screw hole 58a, and the race ring 53b has a fitting insertion hole 58b. The race rings 53 a and 53 b are fastened by bolts 59. At that time, misalignment between the race rings 53a and 53b is prevented by the inlay structure by the convex portion 60a formed on the race ring 53a and the recess 60b formed on the race ring 53b. A bolt 59 is tightened to pressurize the race 53b toward the race 53a, so that a preload (minus clearance) is applied to the bearing.

JP 2006-266458 A

  However, the inlay structure of the double row rolling bearing 51 described in Patent Document 1 has been found to have the following problems. That is, in the inlay structure including the convex portion 60a formed on the raceway ring 53a and the concave portion 60b formed on the raceway ring 53b, it is necessary to process the convex portion 60a and the concave portion 60b with a high degree of accuracy until a small fit. However, since the convex part 60a and the concave part 60b are formed in the thin and large-diameter race rings 53a and 53b, it is difficult to process with high accuracy. In addition, there is a problem that the manufacturing cost increases significantly if high precision processing is performed.

  On the other hand, it has also been found that if the allowable dimension range of the fitting clearance between the convex portions 60a and the concave portions 60b is relaxed in order to reduce the manufacturing cost, the following problems occur. For example, in the CT scanner device 100 shown in FIG. 5, as described above, the inspection unit 101 has the ring-shaped rotating body 105 (X-ray irradiation device 103 and detection unit 104 facing each other in the diameter direction) ( Gantry) is provided. Since the rotating body 105 is rotatably supported by the cylindrical fixed portion 106 via the bearing 51 in a state close to a cantilever, a large moment load is applied to the bearing 51. It is in a severe usage environment where it rotates at a high speed of 120 rpm or higher.

  In addition, medical devices require consideration so as not to give anxiety or fear to the patient undergoing the examination. In particular, in the case of a CT scanner device, the patient himself / herself is located at a tunnel entrance called a gantry. Therefore, mechanical operation sound and electrical excitation sound are disliked. As a result, low noise, low vibration, and high rigidity are required for the bearing, and since the CT scanner device is an expensive medical device, excellent durability is desired, and the bearing has a long life. Required.

  Since the bearing is in use as described above, if the allowable dimension range of the fitting clearance between the convex portion 60a and the concave portion 60b is expanded, the misalignment of the pair of race rings 53a and 53b cannot be sufficiently suppressed, and the bearing It is difficult to set the appropriate internal preload (minus clearance) or the smallest possible clearance with the two right and left rows of rings, and there is a concern about problems such as preload loss during the moment load action. It was found that there were problems with vibration and high rigidity.

  In view of the above problems, the present invention can suppress the misalignment of a pair of races that form an outer member or an inner member, has low noise, low vibration, and high rigidity, and is easy to manufacture and low cost. An object of the present invention is to provide a double row rolling bearing.

  As a result of various studies to achieve the above-described object, the present inventors have a new idea of suppressing the misalignment of the pair of track rings by the positioning member, apart from the fixing bolts of the pair of track rings, The present invention has been reached.

As technical means for achieving the above-mentioned object, the present invention provides an outer member having two raceway surfaces on the inner periphery, and an inner member disposed inside the outer member and having two track surfaces on the outer periphery. square and the member, and the rolling elements of the two rows incorporated between the track surface and the raceway surface of the inner member of the outer member, it consists of a cage holding the rolling elements, the pre-Symbol inwards member In the double row rolling bearing formed with a pair of race rings, both race rings are fastened by fixing bolts , and the outer member and the inner member are provided with holes that are fastened and fixed to a mating member of a used device . The end surfaces of the pair of track rings that are in contact with each other are flat surfaces , a positioning hole is provided in the pair of track rings, and a positioning member is inserted into the positioning hole, thereby causing radial misalignment of the pair of track rings. I am one that inhibit, the positioning hole reamer hole And, and, while the number 2 or more, characterized in that the positioning member is a reamer pin.

With the above configuration, it is possible to suppress the radial misalignment of the pair of races, and to realize a low-noise, low-vibration, high-rigidity, easy-to-manufacture and low-cost double-row rolling bearing. By making the end surfaces of the pair of race rings in contact with each other flat, the spigot structure can be abolished, so that manufacture is easier and cost reduction can be achieved. In addition, since the inner member is formed of a pair of bearing rings, the bearing clearance can be easily set by arranging the double-row rolling bearings in a rear arrangement advantageous for moment load and abutting the end faces of the pair of bearing rings. it can. The positioning holes are reamer holes, and the number thereof is 2 or more, and the positioning member is a reamer pin (positioning pin), so that the position in the vertical and horizontal directions and the rotational direction can be determined. The product can be used as appropriate, which is preferable in terms of quality and cost.

The pitch angle between the reamer holes is preferably set to an angle that is not a multiple of the pitch angle between the rolling elements. The reason is that, after the reamer pin is driven, the fit between the reamer pin and the reamer hole may be an interference fit, and thus there is a possibility that distortion corresponding to the number of reamer holes may occur on the raceway surface. Since this strain can induce and amplify periodic vibrations in relation to the number of rolling elements, the problem can be solved by setting the pitch angle between reamer holes to an angle that is not a multiple of the pitch angle between rolling elements. Can be resolved.

By making the fitting clearance between the reamer pin and the reamer hole smaller than the fitting clearance between the fixing bolt and the fitting insertion hole, misalignment of the pair of race rings can be effectively suppressed.

  By using the double row rolling bearing as the back surface arrangement of the angular ball bearing, low noise, low vibration, and high rigidity can be achieved at high speed. This double row rolling bearing is suitable for a CT scanner device.

  According to the present invention, it is possible to realize a double-row rolling bearing that can suppress misalignment of a pair of races, has low noise, low vibration, and high rigidity, is easy to manufacture, and is low in cost.

It is a longitudinal cross-sectional view of the double row rolling bearing which concerns on the reference example 1 of this invention. It is a longitudinal cross-sectional view in the position where the circumferential direction of said double row rolling bearing differs. It is a longitudinal cross-sectional view in the position where the circumferential direction of said double row rolling bearing differs. It is a front view of said double row rolling bearing. It is a schematic diagram showing a CT scanner device. It is a longitudinal cross-sectional view of the double row rolling bearing which concerns on the reference example 2 of this invention. It is a longitudinal sectional view of a double row rolling bearing according to the implementation embodiments of the present invention. It is a longitudinal cross-sectional view of the double row rolling bearing which concerns on the reference example 3 of this invention. It is a longitudinal cross-sectional view of the conventional double row rolling bearing.

  Embodiments of the present invention will be described below with reference to the drawings.

A double-row rolling bearing according to Reference Example 1 of the present invention will be described with reference to FIGS.

1 to 3 are longitudinal sectional views of the double row rolling bearing of this reference example , and FIG. 4 is a front view partially including a transverse section. 1 to 3 are different in circumferential position, FIG. 1 is a longitudinal section taken along line EE in FIG. 4, FIG. 2 is a longitudinal section taken along line FF in FIG. 4, and FIG. A longitudinal section at line G is shown. As an outline of these longitudinal sections, in FIG. 4, the positions where the mounting holes for mounting the double row rolling bearing 1 to the equipment to be used are provided in the EE cross section, and there are eight positions in the circumferential direction. The positions where the positioning holes for suppressing the misalignment of the pair of race rings are shown in the FF cross section, and there are three positions in the circumferential direction, and the positions where the bolt insertion holes for fastening the pair of race rings are provided. Eight locations in the circumferential direction are shown in the GG section. Details will be described later.

  As shown in FIG. 1, the double row rolling bearing 1 mainly includes an outer member 2, an inner member 3, a ball 4 as a rolling element, and a cage 5. Both the outer member 2 and the inner member 3 are ring-shaped and arranged concentrically. The inner member 3 includes a pair of race rings 3a and 3b. End surfaces 10a and 10b of the race rings 3a and 3b that are in contact with each other are formed as flat surfaces and do not have an inlay structure. The outer member 2 is formed with two rows of raceway surfaces 6 and 6 on the inner circumference, and the outer circumference of each of the pair of raceways 3a and 3b forming the inner member 2 is on the raceway surface of the outer member 2. 6 and 6 are formed on the raceway surfaces 7 and 7 facing each other. Two rows of balls 4 are incorporated between the raceway surfaces 6 and 6 of the outer member 2 and the raceway surfaces 7 and 7 of the inner member 3. The cage 5 is disposed between the outer member 2 and the inner member 3, and the balls 4 in each row are held at predetermined intervals in the circumferential direction.

The double row rolling bearing 1 of this reference example is a double row angular ball bearing in which balls 4 are arranged in two rows. The bearing portions in both rows are arranged in the back, and the intersection of the lines of action of the rolling element load is outside the pitch circle of the balls 4. The ball 4 and the raceway surfaces 6 and 7 are in contact with each other with a contact angle α, and the contact angle α is, for example, about 30 °. By making the pair of race rings 3a, 3b into the inner member 3, the double-row rolling bearing 1 is arranged in a back arrangement advantageous for moment load, and the end faces 10a, 10b of the pair of race rings 3a, 3b are abutted, Bearing clearance (preload or minute clearance) can be set easily. This double row rolling bearing 1 is an ultra-thin type double row rolling bearing in which the ratio Db / PCD of the diameter Db of the ball 4 to the pitch circle diameter PCD is 0.03 or less.

  The bearing rings 3a and 3b are formed with a shoulder drop portion 12 having a small outer periphery. The shoulder drop portion 12 forms a labyrinth in cooperation with the inner diameter end portion of the seal member 11 attached to the inner periphery of the outer member 2. By making the outer diameters of the shoulder drop portions 12 equal, it becomes possible to use the common seal member 11 on both sides.

The outer member 2 is provided with a mounting hole 8 in the form of a through-hole for passing a bolt (not shown), and is fastened and fixed to the mating member of the equipment used by the bolt. In this reference example , as shown in FIG. 4, the attachment holes 8 are provided at eight locations at equal intervals in the circumferential direction. The race 3a of the inner member 3 is provided with a screw hole 9 that is screwed with a bolt (not shown), and is fastened and fixed to a mating member of the equipment used by the bolt. Similar to the outer member 2, as shown in FIG. 4, the screw holes 9 are provided at eight locations at equal intervals in the circumferential direction. However, it is needless to say that the mounting holes 8 and the screw holes 9 are not limited to eight places, and may be provided in a suitable number of places. Moreover, it is not restricted to an equal interval, You may provide at an appropriate unequal interval.

In a normal use state in which the inner diameter and outer diameter of the bearing are fitted to the shaft or the housing, the pair of race rings 3a and 3b forming the inner member 3 are fitted to the shaft to prevent radial misalignment. However, as described above, the double row rolling bearing 1 of the present reference example is fastened and fixed to the mating member of the equipment by bolts at the bearing width surface, so that the two rows of raceways 3a and 3b have a relative diameter. This is a use state in which the effect is great when a moment load is applied, and problems such as preload loss are concerned.

The double-row rolling bearing of this reference example is used in the above-described state, and the configuration for suppressing the misalignment of the pair of race rings 3a and 3b forming the inner member 3 which is a feature thereof is shown in FIG. Based on As described above, the inner member 3 includes a pair of race rings 3a and 3b, and the end faces 10a and 10b of the race rings 3a and 3b that are in contact with each other are formed as flat surfaces. The race rings 3a and 3b are provided with reamer holes 13a and 13b as positioning holes in the form of through holes into which reamer bolts 14 as positioning members are inserted. In this reference example , as shown in FIG. 4, the reamer holes 13a and 13b are provided at three locations at equal intervals in the circumferential direction. However, the reamer holes 13a and 13b are not limited to three places or at equal intervals, and can be set at an appropriate number and at appropriate intervals.

Specifically, if there are at least two fitting portions of the reamer holes 13a and 13b and the reamer bolt 14, the positions in the vertical and horizontal directions and the rotational direction can be determined. However, since the shear load is received, the shear load to be applied is determined. It is desirable to decide in consideration. In general, since the bolt shear stress is 60 to 70% of the tensile stress, the number of reamer bolts 14 is N, the load shear load is W, the allowable tensile stress of the bolt 14 is σ, and the sectional area of the bolt 14 is A. The number of reamer bolts 14 is obtained by the following equation.
N ≧ W / [σ × (0.6 to 0.7) × A]
Therefore, in the double row rolling bearing 1 of this reference example , it is set so as to satisfy the relationship of N ≧ W / [σ × (0.6 to 0.7) × A]. Thereby, sufficient intensity | strength with respect to a shear load is securable.

  The reamer bolt 41 has an outer diameter portion finished with high accuracy, and can regulate the clearance between the reamer holes 13a and 13b of the race rings 3a and 3b when fitted. In this fitting, the clearance between the outer diameter of the fixing bolt 16 (see FIG. 3) and the inner diameter of the fitting insertion hole 17b is B, and the outer diameter of the reamer bolt 14 and the inner diameter of the reamer holes 13a and 13b. When the clearance between them is C, the relationship of clearance B> clearance C is necessary. The reamer bolt 14 and the reamer holes 13a and 13b are ideally combined (in-kind alignment) if possible.

  Further, when the reamer bolts 14 are inserted into the reamer holes 13a and 13b, there is a possibility that an interference fit will occur. At this time, there is a possibility that a distortion corresponding to the number of the reamer bolts 14 occurs on the raceway surface 7. Since this strain may induce and amplify periodic vibrations in relation to the number of rolling elements, in order to avoid this, the pitch angle between the reamer holes 13a and 13a and between the rolling elements 13b and 13b is set between the rolling elements. It is desirable to set an angle that is not a multiple of the pitch angle. In order to clarify this relationship, a partial cross-sectional view is added to FIG. 4, which is a front view of the double row rolling bearing 1, to show the arrangement of the rolling elements 4.

  Here, as shown in FIG. 4, the pitch angle between the positioning holes refers to the center of each of the reamer holes 13 a, 13 a and 13 b, 13 b serving as the positioning holes adjacent to the circumferential direction and the axis O of the rolling bearing 1. Is an angle β formed by two straight lines H and I. The pitch angle between the rolling elements refers to an angle θ formed by two straight lines J and K connecting the centers of the rolling elements 4 and 4 adjacent to each other in the circumferential direction and the axis O of the rolling bearing 1. That is, it is desirable to set the pitch angle β between reamer holes as positioning holes to an angle that is not a multiple of the pitch angle θ between the rolling elements. The same applies to the pitch angle between the remaining reamer holes 13a, 13a and 13b, 13b. The same meaning is used in the present specification and claims.

Specifically, in the double row rolling bearing 1 of this reference example , since the number of balls 4 incorporated in each row is 110, the pitch angle θ between the rolling elements is 3.27 °. Become. On the other hand, since the reamer holes 13a and 13b are arranged at three positions at equal intervals in the circumferential direction, the pitch angle β between the reamer holes is 120 °. Therefore, since the pitch angle β between the positioning holes is set to an angle that is not a multiple of the pitch angle θ between the rolling elements, it is possible to prevent the periodic vibration related to the number of rolling elements from being induced and amplified.

  As described above, the reamer holes 13a and 13b and the reamer bolt 14 are set. Reamer bolts 14 are fitted into the reamer holes 13 a and 13 b, and a pair of race rings 3 a and 3 b forming the inner member 3 are fastened and fixed with nuts 15. Thereby, the radial misalignment of the races 3a and 3b can be suppressed. As the reamer bolt 14, a commercially available product can be used as appropriate, which is preferable in terms of quality and cost.

  Next, the pair of race rings 3a and 3b are fastened with fixing bolts. This state will be described with reference to FIG. Of the pair of race rings 3a and 3b forming the inner member 3, the race ring 3a is provided with a screw hole 17a, and the race ring 3b is provided with a bolt fitting hole 17b. As described above, the clearance B between the outer diameter of the fixing bolt 16 and the inner diameter of the fitting insertion hole 17b is set larger than the clearance C between the inner diameters of the reamer holes 13a and 13b.

  As shown in FIG. 4, the screw holes 17a and the fitting insertion holes 17b are provided at eight positions at equal intervals in the circumferential direction. However, the screw holes 17a and the fitting insertion holes 17b are not limited to eight places at equal intervals, and can be set at an appropriate number and at appropriate intervals.

As shown in FIG. 3, the fixing bolt 16 is passed through the fitting insertion hole 17b and screwed into the screw hole 17a, and is screwed and tightened until the end faces 10a and 10b of the race rings 3a and 3b come into contact. As described above, in the double row rolling bearing 1 of this reference example , since the reamer holes 13a and 13b and the reamer bolt 14 are provided, the misalignment of the pair of race rings 3a and 3b is suppressed. When screwed and tightened until the end faces 10a and 10b come into contact with each other, an appropriate preload (for example, about -20 to 0 μm) or a small clearance (for example, about 0 to 20 μm) by the fixed position preload has two rows of left and right race rings 3a. 3b can be obtained uniformly and stable bearing performance can be obtained. Moreover, since the double row rolling bearing 1 of this reference example does not have the spigot structure, it is easy to manufacture and can realize low cost.

FIG. 5 shows a state in which the double row rolling bearing 1 of this reference example is used in the CT scanner device 100. The double row rolling bearing 1 is assembled between the fixed portion 106 of the CT scanner device 100 and the rotating body 105, and is fastened and fixed to the fixed portion 106 through bolts (not shown) in the mounting holes 8 of the outer member 2 shown in FIG. A bolt (not shown) is screwed into the screw hole 9 of the side member 3 to be fastened and fixed to the rotating body 105. Accordingly, the rotating body 105 is rotatably supported by the fixed portion 106 via the double row rolling bearing 1. Since the rotating body 105 is equipped with an imaging device such as the X-ray irradiation device 103 and the detection unit 104, a large moment load is applied to the rolling bearing 1, and it is used at a high-speed rotation of 120 rpm or more in such a load state. Is done.

In the double row rolling bearing 1 according to the present reference example , the center misalignment of the pair of race rings 3a and 3b is suppressed, and an appropriate preload or minute clearance is provided in the two rows on the left and right sides. Since it can be obtained uniformly with a ring, it is possible to obtain stable bearing performance with high speed rotation, low noise, low vibration and high rigidity. For this reason, the CT scanner device 1 provides remarkable effects such as reducing the burden on the patient by shortening the imaging time, reducing the amount of exposure by imaging, and reducing the patient's anxiety and fear due to low noise.

Next, a double row rolling bearing according to Reference Example 2 of the present invention will be described with reference to FIG. In this double row rolling bearing 1, the configuration in which the reamer bolt 14 is directly screwed into the raceway ring 3a is different from the reference example 1 , and the other configuration is the same as the reference example 1 . Specifically, in Reference Example 2 , only a cross section provided with a reamer hole for suppressing the misalignment between the inner and outer races is shown in FIG. 6, but an attachment hole for attaching the bearing to the device used is provided. cross section, the front cross-section and a bearing provided with insertion hole for fastening the both bearing rings of right and left are the same as FIGS. 1, 3 and 4 of example 1. Parts having the same functions as those of Reference Example 1 are denoted by the same reference numerals, and the main points will be described.

In the double-row rolling bearing 1 of Reference Example 2 , the race ring 3a is provided with a reamer hole 13a and a screw hole 13c concentrically therewith, and the race ring 3b is provided with the same reamer hole 13b as in Reference Example 1. It has been. The reamer bolt 14 is inserted into the reamer holes 13a and 13b and screwed into the screw holes 13c to fasten and fix the races 3a and 3b. Thereby, the misalignment of the pair of race rings 3a and 3b forming the inner member 3 is suppressed. In Reference Example 2 , the nut of the reamer bolt 14 and the counterbore for that can be omitted, so the number of parts and the processing can be reduced. About the other point, all the content demonstrated about the reference example 1 mentioned above applies mutatis mutandis, and description is abbreviate | omitted.

The double row rolling bearing according to the implementation embodiments of the present invention will be described with reference to FIG. In this double row rolling bearing 1, the configuration in which the positioning member is a positioning pin is different from that in Reference Example 1 , and the other configuration is the same as that in Reference Example 1 . Also in the present embodiment, FIG. 7 shows only a cross section provided with a reamer hole for restraining misalignment between the inner and outer races. 1 and 3 and 4 of Reference Example 1 are the same as the cross section provided with the fitting insertion holes for fastening both the bearing rings and the front of the bearing. Parts having the same functions as those of Reference Example 1 are denoted by the same reference numerals, and the main points will be described.

In the double row rolling bearing 1 of the present embodiment, the positioning pins 14 'are inserted into the reamer holes 13a and 13b of the race rings 3a and 3b to suppress misalignment of the race rings 3a and 3b. Here, the positioning pin 14 'means a reamer pin that is fitted in the reamer holes 13a and 13b and has the same fit as the reamer bolt in the reference example 1 described above. If the fitting between the positioning pin 14 ′ and the reamer holes 13 a and 13 b is set to an appropriate interference fit, positioning pin fixing means is not necessary. Since the positioning pin 14 'is used in the present embodiment, machining of the spot facing portions of the race rings 3a and 3b can be omitted, and a commercially available product can be adopted as the positioning pin 14' as appropriate, in terms of quality and cost. Is preferable. Regarding the other points, the reamer bolt in Reference Example 1 described above is read as a positioning pin, and all the contents described in Reference Example 1 apply mutatis mutandis, and the description is omitted.

A double row rolling bearing according to Reference Example 3 of the present invention will be described with reference to FIG. In this double row rolling bearing, a reamer bolt is applied to an inlay structure race. Also in this reference example , FIG. 8 shows only a cross section provided with a reamer hole for suppressing the misalignment between the inner ring raceway rings. configuration where the insertion hole is provided for fastening the two bearing rings, and the front of the bearing, the main point and Figures 1, 3 and 4 of example 1 are the same.

In the present reference example shown in FIG. 8, the reamer bolt 14 and the reamer are also provided when the allowable dimension range of the fitting clearance is relaxed in order to reduce the processing cost of the projections 18 a and the recesses 18 b of the inlay structure of the race rings 3 a and 3 b. With the addition of the holes 13a and 13b, misalignment of the races 3a and 3b can be suppressed with high accuracy. As a different point from the reference example 1 , the outer member 2 has a flange portion and a lubricant supply passage 19. Parts having the same functions as those of Reference Example 1 are denoted by the same reference numerals, and description thereof is omitted.

The above-described implementation form and reference example are, in summary, the fixing bolts a pair of bearing rings apart, by installing the positioning member for the radial positioning (e.g., reamer bolts, positioning pins), This is a double row rolling bearing in which the radial misalignment between the races is regulated. Since the center misalignment of the pair of race rings is suppressed, when screwed in and tightened until the end faces of the race rings come into contact, appropriate preload or minute clearance can be obtained uniformly with two rows of race rings, so high speed rotation However, low noise, low vibration, high rigidity and stable bearing performance can be obtained.

The implementation form, rolling is exemplified ball 4 as a moving body is not limited to this, it is possible to use rollers tapered rollers or cylindrical.

  The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the spirit of the present invention. All equivalents and equivalents of the claims, and all modifications within the scope of the claims are embraced by the claims.

DESCRIPTION OF SYMBOLS 1 Double row rolling bearing 2 Outer member 3 Inner member 3a Track ring 3b Track ring 4 Rolling body 5 Cage 6 Track surface 7 Track surface 8 Mounting hole 9 Screw hole 10a End surface 10b End surface 13a Positioning hole 13b Positioning hole 14 Reamer bolt 14 'Positioning pin 16 Fixing bolt 17a Screw hole 17b Insertion hole 100 CT scanner device B Clearance C Clearance O Shaft center α Contact angle β Pitch angle between positioning holes θ Pitch angle of rolling elements

Claims (11)

An outer member having two raceway surfaces on the inner periphery, an inner member disposed inside the outer member and having two raceway surfaces on the outer periphery, the raceway surface of the outer member and the track of the inner member A pair of rolling elements incorporated between the two surfaces and a cage for holding the rolling elements, wherein either one of the outer member and the inner member is formed by a pair of race rings. In double row rolling bearings, which are fastened with fixing bolts,
A double row rolling bearing characterized in that a positioning hole is provided in the pair of race rings, and a positioning member is fitted into the positioning hole to suppress radial misalignment of the pair of race rings.   The double-row rolling bearing according to claim 1, wherein end surfaces of the pair of race rings that are in contact with each other are flat surfaces.   The double row rolling bearing according to claim 1 or 2, wherein the pair of race rings are inner members.   The double row rolling bearing according to any one of claims 1 to 3, wherein the positioning member is a reamer bolt.   The double row rolling bearing according to any one of claims 1 to 3, wherein the positioning member is a positioning pin.   The double-row rolling bearing according to any one of claims 1 to 3, wherein the number of the positioning holes is two or more.   7. The double row rolling bearing according to claim 6, wherein the pitch angle between the positioning holes is set to an angle that is not a multiple of the pitch angle between the rolling elements.   When the number of the reamer bolts is N, the load shear load is W, the allowable tensile stress σ of the bolt, and the cross-sectional area A of the bolt, a relationship of N ≧ W / [σ × (0.6 to 0.7) × A]. The double-row rolling bearing according to claim 4, wherein:   The double row rolling according to any one of claims 1 to 8, wherein a fitting clearance between the positioning member and the positioning hole is smaller than a fitting clearance between the fixing bolt and the fitting insertion hole. bearing.   The double row rolling bearing according to any one of claims 1 to 9, wherein the double row rolling bearing is a double row angular ball bearing.   The double-row rolling bearing according to any one of claims 1 to 10, which is used in a CT scanner device.

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