WO2006114991A1

WO2006114991A1 - Rolling bearing and retainer for rolling bearing

Info

Publication number: WO2006114991A1
Application number: PCT/JP2006/307097
Authority: WO
Inventors: Yosuke Oya; Kengo Hiramatsu
Original assignee: Ntn Corporation
Priority date: 2005-04-19
Filing date: 2006-04-04
Publication date: 2006-11-02

Abstract

A rolling bearing and a retainer for the rolling bearing. To securely prevent the retainer from coming off, the retainer is formed of a plurality of circular arc-shaped segments, these segments are joined to each other endlessly in an annular shape so that a non-connection part is absent therein in the circumferential direction. To prevent or suppress the occurrence of noise by improving the weight balance of the segment retainer, the plurality of circular arc-shaped segments are jointed to each other in the circumferential direction to form them in an annular shape, pockets for storing rolling elements are formed in the retainer at prescribed intervals in the circumferential direction, the non-connection part of the segment is formed at a part of the retainer in the circumferential direction, and cover members increasing the releasing forces of rolling elements in the pockets positioned at the end parts of the segments facing the non-connection part adjacent to each other in the circumferential direction more than those of the rolling elements in the other pockets are installed on the axial opening sides of the pockets positioned at the end parts of the segments facing the non-connection part adjacent to each other in the circumferential direction.

Description

Specification

Rolling bearing and rolling bearing cage

Technical field

[0001] The present invention relates to an ultra-thin and large-sized rolling bearing used for, for example, industrial robots, machine tools, medical equipment, and the like, and a cage incorporated in the bearing.

Background art

FIG. 20 shows an example of a CT scanner device which is a kind of medical equipment. As shown in the figure, in the CT scanner device, X-rays generated by the X-ray tube device 1 are passed through a wedge filter 2 for making the intensity distribution uniform and a slit 3 for limiting the intensity distribution. To illuminate subject 4. The X-rays that have passed through the subject 4 are received by the detector 5, converted into an electrical signal, and sent to a computer not shown.

[0003] Each component such as the X-ray tube device 1, wedge filter 2, slit 3, and detector 5 in this CT scanner device is a substantially cylindrical rotation supported rotatably on a fixed base 7 via a bearing 6. Attached to the gantry 8 and rotated around the subject 4 by the rotation of the rotating gantry 8

[0004] In the CT scanner device, projection data covering all angles in the examination cross section of the subject 4 is obtained by the rotational motion of the subject 4 of the X-ray tube device 1 and the detector 5 facing each other. A tomographic image is obtained by a reconstruction program programmed in advance from these data modules.

[0005] In this CT scanner device, the inner peripheral surface of the fixed base 7 is formed to have a large diameter (generally about lm in diameter) enough for the subject 4 to enter, so the bearing 6 between the fixed base 7 and the rotary base 8 For this, a bearing having a remarkably small cross section relative to its diameter, that is, a so-called ultra-thin type rolling bearing is used.

[0006] As shown in FIG. 21, this bearing includes a ring-shaped outer ring 12, a ring-shaped inner ring 13 concentrically arranged on the inner peripheral side of the outer ring 12, and a raceway between the outer ring 12 and the race of the inner ring 13. The main components are a plurality of rolling elements 14 (balls are illustrated in the figure) interposed so as to be freely rotatable, and a retainer 15 that holds the rolling elements 14 at predetermined intervals in the circumferential direction. [0007] Conventionally, a split type cage made of grease has been widely used for ultra-thin type rolling bearings for CT scanner devices. As shown in FIG. 22, this type of cage 15 has an end-like structure in which a plurality of arc-shaped segments 16 are connected in the circumferential direction and formed into an annular shape, and a non-connecting portion 17 is provided in a part thereof. Have As shown in FIGS. 23 and 24, the segment 16 includes an arc-shaped base 18, a plurality of pillars 19 extending from the base 18 to one side in an axial direction, and a plurality of pillars 19 adjacent to each other. And a plurality of pockets 20a, 20b. These pockets 20a and 20b have a shape opened on one side (the upper side in the figure) in the axial direction. The column portion 19 extends in the axial direction beyond the pitch circle of the rolling element 14 shown by a one-dot chain line in FIG.

[0008] The pockets 20a and 20b in the illustrated example have two types of shapes. Ie pocket center

A pocket 20a having a concave arcuate surface in plan view with respect to the rolling element insertion portion side (upper side in the figure) than the above-mentioned pitch circle (in the figure), and a holding function and an equal distribution function of the rolling elements 14; The pocket 2 Ob has a straight wall surface in the axial direction and has only the equal distribution function of the rolling elements 14. The pocket 20a has a pocket opening width L1 (see Fig. 24) smaller than the diameter Dw of the rolling element 14 (Ll <Dw), and the rolling of the rolling element 14 to the pocket opening side is restricted. Held in 20a. The pocket 20b has a pocket opening width L2 larger than the diameter Dw of the rolling element 14 (L2> Dw), and the rolling element 14 is freely movable in the axial direction. Therefore, the pocket 20b does not have a holding function like the pocket 20a, but has only a function of equally arranging the rolling elements 14. Each segment 16 has these two types of pockets 20a and 20b alternately formed in the circumferential direction. The cross section in the radial direction (cross section perpendicular to the drawing sheet) is a concave curved surface with the center of curvature as the center of curvature. The two types of pockets 20a, which have the ability to hold rolling elements, and pockets 20b, which do not have the ability to hold rolling elements, are provided in order to ensure that every other pocket 20a that restrains the rolling elements 14 is placed from the viewpoint of ease of assembly. is there.

[0009] The rolling elements 14 are incorporated into the pockets 20a and 20b by pushing the rolling elements 14 from the rolling element insertion portions of the pockets 20a and 20b to the back side. At this time, the pocket 20a needs to push the rolling element 14 while expanding the column 19 on the entrance side.Pocket 2 Ob does not require such trouble, so the rolling element 14 is incorporated into the cage 15. The process can be simplified. Note that the shape and structure of the pocket described above are merely examples, and various shapes and structures may be used depending on the use conditions of the bearing, such as a single pocket. Structural pockets can be used.

[0010] At both ends of each segment 16, as shown in FIG. 23, connecting portions 21a, 21b for connecting adjacent segments are provided. Here, a connecting portion 21b that engages with the connecting portion 21a of the segment 16 that is the connecting partner and is engaged in the concave and convex portions in the circumferential direction is illustrated. One connecting portion 21a has a convex shape with a wide front end. In the example shown in the figure, the connecting portion 21a is composed of a substantially cylindrical surface portion extending in the radial direction of the cage 15 and a neck portion narrower than that. Yes. The other connecting portion 21b is formed in a cylindrical concave shape that matches the above-described convex connecting portion. When connecting adjacent segments, the connecting portion 21a of one segment 16 is pushed into the connecting portion 21b of the other segment 16 in the radial direction. As a result, the connecting portions 21a and 21b are fitted to each other, and separation of the segments in the circumferential direction is prevented (see, for example, Patent Documents 1 to 3).

Patent Document 1: Japanese Unexamined Patent Application Publication No. 2004-19921

Patent Document 2: JP-A-2004-162879

Patent Document 3: Japanese Patent Application Laid-Open No. 2004-218745

Disclosure of the invention

Problems to be solved by the invention

[0011] By the way, in the bearing having the cage 15 composed of a plurality of segments 16, when assembling the bearing, the segments 16 are connected as described above, and the rolling elements 14 are incorporated into each pocket. In view of its assemblability, as shown in FIG. 22, a non-connecting portion 17 is provided at one place in the circumferential direction of the cage 15, and a segment 16 is formed from an end 22 adjacent to the non-connecting portion 17. Assembling the cage 15 between the inner and outer rings in a connected state facilitates the assembly of the cage 15.

[0012] Further, the segment 16 constituting the cage 15 described above is an injection-molded product made of resin, and fiber reinforced polyamide resin (PA66) is generally adopted as the material thereof. However, this PA66 has a coefficient of linear expansion larger than that of steel, which is the bearing ring material of the bearing, so the dimensional difference increases due to temperature changes, and it expands due to water absorption, so that it is used in CT scanner devices. In the case of large bearings, the circumferential length of the cage 15 changes significantly. In order to absorb the change in the circumferential length of this cage 15, the circumferential direction of the connected segments 16 The non-connecting part 17 is provided in one direction.

[0013] To improve the assemblability by providing the non-connecting portion 17 to the retainer 15 while applying force also means that the retainer 15 can be easily removed. For this reason, if the bearing mounting ring is defective and the bearing race is deformed, this deformation increases the advance and delay of the rolling element 14 in the circumferential direction of the cage 15 when the bearing rotates. There is a possibility of separation from the end 22. Similarly, if the bearing is designed only by the disturbance of the bearing peripheral force described above (for example, a special design with different contact angles on the left and right sides of a four-point contact ball bearing), and when the rolling delay of the rolling element 14 becomes significantly large There is a possibility that the cage 15 is detached. It is desired to determine under what conditions this detachment of the cage 15 may occur and to take countermeasures.

[0014] Therefore, the applicant of the present invention proposes the present invention as a result of examining and examining the mechanism of the cage detachment, and the purpose thereof is to reliably prevent the detachment of the cage. It is providing the rolling bearing and the cage for rolling bearings.

Means for solving the problem

[0015] As a technical means for achieving the above-mentioned object, the present invention is a rolling bearing retainer constituted by a plurality of arc segments, in which the segments are connected in an annular shape and the circumferential direction thereof. It is characterized by having an endless shape having no unconnected portion. The segment constituting the cage is preferably made of a resin such as PPS (polyphenylene sulfide).

[0016] Here, the applicant of the present invention is a rolling bearing incorporating an endless conventional cage having a non-connecting portion, and an endless retainer of the present invention having no non-connecting portion. The built-in rolling bearing was tested on the assumption that it was mounted on a CT scanner device. As a result of the test, the conventional cage was disengaged from the inner and outer rings, and the retainer of the present invention was a force that did not cause separation from the inner and outer rings. As a result, in the cage of the present invention, the inner and outer rings are affected by disturbance from the periphery of the bearing (for example, a mounting failure of the bearing) and the design of the bearing (for example, a special design in which the left and right contact angles are different for a four-point contact ball bearing). It is possible to reliably prevent departure from the vehicle.

[0017] Here, the applicant of the conventional retainer 15 uses a mechanism of detachment as follows. Considered. If there is deformation of the bearing ring due to a bearing installation failure, the rolling element 14 will advance on the leading side with respect to the rotational direction in the state before separation shown in Fig. 10a, while the rear end (retainer) At the end 22) of 15, the rolling element 14 is delayed, and the advancement and delay of the rolling element 14 increases. In the state at the time of separation shown in FIG. 10b, the rolling element 14 at the intermediate part becomes a fulcrum by the tensile force from the front side of the cage 15, and the rear end of the cage 15 is deformed into an arcuate shape. In the state after disengagement shown in FIG. 10c, after the retainer 15 is disengaged, the rolling element 14 located at the end is disengaged further from the pockets 20a and 20b.

[0018] In view of the above, the present invention forms a plurality of arc-shaped segments in the circumferential direction by joining them in the circumferential direction and forms pockets for accommodating rolling elements at predetermined intervals in the circumferential direction. A rolling bearing retainer having a segment non-connecting portion in a part, in a pocket located at an end of at least one of the segments adjacent to the non-connecting portion in the circumferential direction. This is characterized by the provision of a means for preventing separation from the other pockets.

[0019] Further, the cage having the above-described constituent force can be configured as a rolling bearing by being combined with an inner ring, an outer ring, and a plurality of rolling elements incorporated between the raceways of the inner and outer rings. The cage in the bearing exhibits a function of holding a plurality of rolling elements at a predetermined interval in the circumferential direction.

[0020] In the present invention, the separation force of the rolling element is made larger than that of the other pocket in the pocket located at least one end of the circumferentially opposed segment adjacent to the unconnected portion. By providing the prevention means, it is possible to increase the separation force of the rolling elements in the pocket located at the end of the segment adjacent to the non-connecting portion. In other words, an increase in the separation force of the rolling elements means that the rolling elements are difficult to separate from the aforementioned pocket, and as a result, the segments are difficult to separate from the rolling elements.

[0021] It should be noted that the above-described detachment preventing means may be provided in the pocket at the end of at least one of the segments adjacent to the non-connecting portion. That is, if the rotational direction of the bearing is clear, the separation preventing means may be provided in the pocket at the end of the segment that is the last in the rotational direction. If the rotational direction of the bearing is not clear, it is only necessary to provide a means for preventing separation in the pockets at the ends of both segments facing and adjacent to the unconnected portion. [0022] As the detachment preventing means in the above-described configuration, a structure in which a lid member is attached to the axial opening side of the pocket located at the end of the segment facing the circumferential direction adjacent to the non-connecting portion is desirable. In this structure, the axial opening side of the pocket is closed with a lid member to forcibly prevent the rolling element from detaching from the pocket.

[0023] On the other hand, the segment type cage has a poor weight balance in relation to the pocket being opened and being inserted into the bearing from the other side. In other words, since the pocket is open only on one side in the axial direction, the side where the pocket is open becomes lighter, and the center of gravity of the pocket is also displaced. Therefore, although depending on the operating conditions, the locus (behavior) of the cage during rotation of the bearing is not stable, and the cage may rub against the inner ring or outer ring. The sound at this time generates an abnormal noise, which may be difficult to apply to applications that emphasize sound.

[0024] Therefore, the segment type cage is also opposed in the circumferential direction adjacent to the non-connecting portion in order to improve the weight balance of the segment type cage and prevent or suppress the generation of abnormal noise. A structure in which a cover member is attached to the axial opening side of the pocket located at the end of the segment is desirable. By providing a lid member that covers the opening of the pocket, the weight balance of the cage is improved and the behavior is stabilized as compared with the conventional case where the pocket remains open. To improve the weight balance of the cage, it is desirable to keep the axial distance from the center of the pocket to the center of gravity of the segment within 5% of the pocket diameter. Further, in the rolling bearing cage, it is desirable to provide the main body with a portion for receiving the rolling element in the circumferential direction. With such a configuration, the circumferential movement of the rolling element is received exclusively by the main body, in other words, the rolling element and the lid do not interfere in the circumferential direction. Therefore, a lid that does not require any particular strength to the lid can contribute exclusively to the weight balance of the cage.

[0025] As another detachment preventing means, a structure in which the opening width of the pocket located at the end of the segment facing the circumferential direction adjacent to the non-connecting portion is smaller than the opening width of the other pocket is desirable. . In the case of this structure, increasing the amount of rolling element in the pocket makes it difficult for the rolling element to leave the pocket. In addition, the axial length of the pocket peripheral portion located at the end of the segment facing the circumferential direction adjacent to the non-connecting portion is set to the other pocket peripheral portion. A structure that is longer than the axial length, or a structure where the thickness of the pocket peripheral edge located at the end of the segment facing the circumferential direction adjacent to the unconnected portion is larger than the thickness of the other pocket peripheral edge. Is also possible. In the case of these structures, it is difficult for the rolling elements to be detached from the pockets by improving the rigidity of the peripheral portion of the pocket of the segment.

[0026] In addition to changing the shape of the end portion of the segment as described above, as another separation preventing means, the segment facing the circumferential direction adjacent to the non-connecting portion has higher hardness than the other segments. It can be made of a material. If the material is changed in this way, the rolling element is less likely to be detached from the pocket by increasing the hardness at the peripheral edge of the pocket of the segment.

[0027] In the rolling bearing having the above-described configuration, either the outer ring or the inner ring is fixed to the rotating mount of the CT scanner device that rotates around the subject, and the other is fixed to the fixed mount of the CT scanner device. With this configuration, a highly reliable CT scanner device can be provided.

The invention's effect

[0028] According to the present invention, when the mounting environment of the bearing is bad, that is, in a usage environment in which the bearing is deformed, or the internal design of the bearing, for example, a four-point contact ball bearing, the left and right contact angles are different. Even in the case of a special design or the like, even if there is a bearing mounting failure, it is possible to reliably prevent the cage from being detached, so it is possible to provide a highly reliable rolling bearing. Further, the weight balance of the cage is improved and the behavior is stabilized. As a result, the cage becomes difficult to contact with the raceway, so that the generation of abnormal noise can be prevented or at least suppressed.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 8 shows an example of a specific structure of an ultra-thin type rolling bearing assembled to a CT scanner device (see FIG. 20). As shown in FIG. 8, this bearing is mainly composed of an inner ring 23, an outer ring 24, rolling elements 25, and a cage 26. The inner ring 23 has a track on the outer peripheral surface and the outer ring 24 has a track on the inner peripheral surface, and a plurality of rolling elements 25 are rotatably incorporated between the tracks of the inner and outer rings 23, 24. The cage 26 is interposed between the inner and outer rings 23 and 24 and holds the rolling elements 25 at a predetermined interval in the circumferential direction. Normally, a seal is attached to seal the bearing space between the inner and outer rings 23 and 24 to prevent leakage of lubricant and intrusion of foreign matter by external force. Here, illustration is omitted.

[0030] In this embodiment, a ball is exemplified as the rolling element 25, but a roller may be used. Further, the present invention is not limited to a single row bearing in which the number of rows of rolling elements 25 is one, but can also be applied to a double row bearing in which two rows of rolling elements are arranged.

[0031] This bearing has a ratio φ between the diameter D of the rolling element 25 and the pitch circle diameter PCD of 0.03 or less (

B

= D /PCD≤0.03) Ultra-thin type rolling bearing, mainly PCD 500mm ~ 15

B

Applicable to large diameter bearings of about OOmm. A specific example is as follows. Diameter of rolling element D: 1Z2 inch (12.7 mm)

B

PCD: 1041.4mm

Ratio of rolling element diameter D to pitch circle diameter PCD φ: 0. 012

B

[0032] The cage 26 in the embodiment shown in FIG. 1 has an endless shape in which a plurality of arc-shaped segments 27 are connected in an annular shape and do not have a non-connecting portion 17 (see FIG. 22) in the circumferential direction. Have a form. Each segment 27 is formed by injection molding a resin material into a predetermined shape. As the resin material, the ambient temperature of the CT scanner bearing is usually about 60 to 80 ° C, so this temperature change has an adverse effect. For example, PPS (polyphenylene sulfide) having a small linear expansion coefficient is suitable for suppressing the expansion due to water absorption.

[0033] In each segment 27, a plurality of pockets for accommodating the rolling elements 25 are formed at equal intervals in the circumferential direction. The pocket has a form in which one side in the axial direction is opened. Further, both ends of each segment 27 are provided with connecting portions for connecting adjacent segments. Note that the shape of the segment 27, the form of the pocket, the incorporation of the rolling elements 25 into the pocket, and the connecting portion structure of the segment 27 are the same as those described with reference to FIG.

[0034] The cage 28 in the embodiment shown in Fig. 2 has a plurality of arc-shaped segments 29 joined in the circumferential direction and formed into an annular shape, and a non-connecting portion 30 is provided in a part of the circumferential direction. It is in the form of an end. As shown in FIG. 3, each segment 29 is formed between an arc-shaped base 31, a column 32 extending from the base 31 to one side in the axial direction, and an adjacent column 32. For example, it is a resin molded product having a plurality of pockets 33a and 33b to be accommodated and having PA66 (nylon 66) force. These pockets 33a and 33b are provided on one side in the axial direction (in the illustration Side).

[0035] As shown in Fig. 3, the pockets 33a and 33b of the cage 28 include a pocket 33a having a holding function and an equal distribution function for the rolling elements 25, and a pocket 33b having only an equal distribution function for the rolling elements 25. There are two types of shapes. The pocket 33a has a pocket opening width L1 smaller than the diameter Dw of the rolling element 25 (Ll <Dw), and the rolling of the rolling element 25 to the pocket opening side is restricted, and the rolling element 25 is held in the pocket 33a. Is done. The pocket 33b has a pocket opening width L2 larger than the diameter Dw of the rolling element 25 (L2> Dw), and the rolling element 25 can freely move in the axial direction.

[0036] Therefore, the pocket 33b does not have a holding function like the pocket 33a, but has only a function of equally arranging the rolling elements 25. In each segment 29, these two kinds of pockets 33a and 33b are alternately formed in the circumferential direction. The pocket 33a with rolling element holding ability and the pocket 33b without rolling element holding ability are provided in order to make every other pocket to restrain the rolling element 25 from the standpoint of incorporation. is there. The assembly of the rolling elements 25 into the pockets 33a and 33b of each segment 29 and the connecting portion structure between the segments 29 are the same as those described in FIG.

[0037] In the cage 28 having the above-described constituent force, the separation force of the rolling element 25 is transferred to another pocket in the pocket 33a located at the end 34 of the segment 29 adjacent to the non-connecting portion 30 in the circumferential direction. A cage detachment preventing means that is larger than 33a and 33b is provided. By providing this separation preventing means, it is possible to increase the separation force of the rolling element 25 in the pocket 33a located at the end portion 34 of the segment 29 adjacent to the non-connecting portion 30. This increase in the separation force of the rolling element 25 makes it difficult for the rolling element 25 to be detached from the aforementioned pocket 33a, and as a result, it is possible to prevent the retainer 28 from separating between the inner ring 23 and the outer ring 24.

[0038] Specific examples of the separation preventing means will be described in the following embodiments. In each of the following embodiments, the rotational direction of the force bearing in which the separation preventing means is provided in the pocket 33a of the end 34 of the two segments 29 adjacent to the non-connecting portion 30 in the circumferential direction is clear. In that case, it is only necessary to provide the separation preventing means only in the pocket 33a of the end portion 34 of the segment 29 which is the rearmost in the rotational direction (see FIGS. 10a, 10b and 10c).

[0039] In the embodiment of the separation preventing means shown in FIG. The lid member 35 is attached to the axial opening side of the pocket 33a located at the end 34 of the segment 29 facing. The lid member 35 may be made of other materials as long as the same material of the segment 29 of the cage 28 is used. The lid member 35 may be bonded by a fixing method such as ultrasonic welding or fitting.

[0040] When the lid member 35 is attached to the axial opening side of the pocket 33a as described above, even if the rolling delay of the rolling element 25 increases due to deformation due to a bearing mounting failure (see FIGS. 10a, 10b, and 10c). By closing the axial opening side of the pocket 33a located at the end 34 of the segment 29 adjacent to the non-connecting portion 30 with the lid member 35. It is possible to forcibly prevent the rolling element 25 from leaving the pocket 33a.

[0041] As other separation preventing means, there are the embodiments shown in Figs.

[0042] In the embodiment of the separation preventing means shown in FIG. 4, the opening width L1 'of the pocket 33a located at the end 34 of the segment 29 adjacent to the non-connecting portion 30 in the circumferential direction is set to another pocket. It is made smaller than the opening width L1 of 33a and 33b (L1, LLl). With such a structure, the amount of rolling element 25 in the pocket 33a can be increased, and as a result, the pocket 33a force rolling element 25 is difficult to be detached.

Further, in the embodiment of the separation preventing means shown in FIG. 5, the axial length HI of the pocket peripheral portion located at the end 34 of the segment 29 adjacent to the non-connecting portion 30 and facing in the circumferential direction HI (Height in the illustration) is made larger than the axial length H2 of the other peripheral edge of the pocket (HI> H2). Alternatively, in the embodiment of the separation preventing means shown in FIGS. 6a and 6b, the thickness T1 of the pocket peripheral part located at the end 34 of the segment 29 adjacent to the non-connecting part 30 and facing in the circumferential direction is different. The thickness of the pocket edge is larger than T2 (T1> T2). In such a structure, the rigidity of the peripheral edge portion of the pocket of the segment 29 can be improved, and as a result, the rolling element 25 is hardly detached from the pocket 33a.

[0044] In addition to changing the end shape of the segment 29 described above as in the embodiment of FIGS. 4 to 6a and 6b, in the other embodiment of the separation preventing means shown in FIG. It is possible to make the segment 29 adjacent to each other in the circumferential direction with a material having higher hardness than the other segments 29. Normally, if the other segment is made of PA66 (nylon 66), the segment 29 adjacent to the non-connecting portion 30 should be made of a material having a higher hardness. For example, PPS (polyphenylene sulfide) may be used. Such a change in material can increase the hardness at the peripheral edge of the pocket of the segment 29 adjacent to the non-connecting portion 30, and as a result, the rolling element 25 is hardly detached from the pocket 33a.

In the rolling bearing incorporating the cages 26 and 28, the outer ring 24 is fixed to the rotary mount 8 of the CT scanner apparatus shown in FIG. 20, and the inner ring 23 is fixed to the fixed mount 7. In this case, the outer ring 24 becomes a rotating member that rotates together with the rotating base 8, and the inner ring 23 becomes a non-rotating fixed member. Depending on the structure of the CT scanner device, the outer ring 24 is fixed on the non-rotating fixed side, contrary to the above. The inner ring 23 may be a rotating side that rotates together with the rotating mount 8.

[0046] The present applicant conducted a test assuming that the rolling bearing incorporating the cages 26 and 28 of this embodiment is mounted on a CT scanner device. Fig. 9 shows how the bearing (specimen) is attached during the test assuming that it is mounted on the CT scanner device. As shown in the figure, the outer ring 36 of the specimen is fixed to the base plate 39a with the bolt 39c through the spacer 39b. It should be noted that the outer ring 36 is bolted at a plurality of equally spaced locations in the circumferential direction (for example, 8 locations at 45 ° intervals). In addition, as spacers 39b, a plurality of types having different thicknesses are prepared. By changing the thickness of these spacers 39b at the bolt fixing points in the circumferential direction, deformation of local deformation in the outer ring 36 is achieved. It is possible to set the amount.

[0047] In this test, the inner ring 37 of the specimen rotates smoothly if it is in a normal mounting state, but a very large deformation occurs in the local area of the specimen (here, the base plate 39a in the bearing mounting section). When the inner ring 37 is rotated by attaching it with a deformation amount of 10 times or more of the assumed flatness, the advance delay of the rolling elements 38 held by the cages 26 and 28 increases, as shown in FIG. In the specimen using the conventional cage 15, separation of the cage 15 occurred. In contrast, in the specimen using the cages 26 and 28 of the embodiment shown in FIG. 1, the cages 26 and 28 are detached even if the advancement and delay of the rolling elements increase due to the deformation of the specimen. There was nothing to do. This reliably prevents the cage from coming off due to disturbances in the bearing peripheral force (for example, bearing mounting failure) and bearing design (for example, a special design with a four-point contact ball bearing with different left and right contact angles). It becomes possible.

[0048] The cage 40 in the embodiment shown in FIG. 11 is formed from a resin material cover. This resin cage 40 is a so-called segment type, and the arc-shaped segment S is arranged in the circumferential direction. It is connected to form a ring. As shown in FIG. 11, each segment S consists of a main body S1 and a lid S2.

[0049] As shown in Fig. 12a and Fig. 12b, the main body S1 has coupling portions 42 and 44 that fit into each other at both ends, and in the main body S1 adjacent in the circumferential direction, the coupling portion of one main body S1 42 and the connecting portion 44 of the other body S 1 fit together.

[0050] Of the coupling portions 42 and 44 at both ends of the main body S1, the coupling portion 42 is a coupling portion main body 42a constituting one end of the main body S1, and a fitting convex portion protruding in the circumferential direction from the coupling portion main body 42a. Including 42b. The coupling portion 44 includes a coupling portion main body 44a that constitutes the other end of the main body S1, and a fitting recess 44b formed on the end surface of the coupling portion main body 44a. The fitting convex portion 42b has a head portion larger than the neck portion formed following the neck portion protruding from the coupling portion main body 42a, and the head portion has a cylindrical shape here. The fitting uneven portion 44b and the fitting uneven portion 42b have complementary shapes.

[0051] The body S1 is formed with a bucket 46 for holding the rolling elements 25 at a plurality of locations in the longitudinal direction (circumferential direction). As shown in FIG. 13, the pocket 46 penetrates the main body S1 in the radial direction (A direction), and opens on one side of the main body S1 in the axial direction (B direction). A pair of claw portions 48 facing in the circumferential direction across the pocket 46 are provided, and the inner surface of the claw portion 48 constitutes a part of the inner surface of the pocket 46.

[0052] A part of the inner surface of the pocket 46 that intersects the cage rotation direction (that is, the cage circumferential direction) is a concave oil sump extending in the radial direction (A direction) of the main body S1. An intersection sump 56 is provided. The intersecting oil sump 56 is, for example, straddled on both sides in the axial direction of the cage axial direction position which substantially coincides with the pitch circle of the array of rolling elements 25. FIG. 17 is a cross-sectional view of the oil reservoir 56 at the intersection. This oil reservoir 56 at the intersection is concentric with the rolling element 25 that is movably held in the pocket 46, and is a curved concave surface or a cylinder having a slightly larger radius of curvature than the curved surface of the rolling element holding surface 50. It is a concave surface such as a planar shape or a rectangular cylindrical surface shape. In the example shown in the figure, the intersection oil sump 56 has a cylindrical shape at the bottom, and has a trapezoidal shape with the opening side widened and the bottom side narrowed as shown in FIG.

[0053] The pocket 46 has an opening (Fig. 14) sandwiched between the pair of claws 48 as described above on one side in the cage axial direction (B direction), but at the bottom on the opposite side of the opening. Concave bottom oil A reservoir 58 is provided. The bottom oil sump 58 has a shape extending in the cage radial direction (A direction). The bottom oil sump 58 should have a minimum depth in contact with the rolling element 25 in a state where the rolling element 25 is at the bottom of the pocket 46, and is deeply formed so as not to contact the rolling element 25 beyond that. Also good. After satisfying this depth condition, the bottom oil sump 58 has a larger curvature radius than the curved surface of the circumferential relief surface 52 which is concentric with the cylindrical surface, the rectangular tube surface, or the rolling element 25. It can be a spherical concave curved surface.

[0054] The thickness of the main body S1 is such that the radial thickness W2 of the general portion of the main body S1 is thinner than the radial thickness W1 of the peripheral portion of each pocket 46 in the main body S1. In other words, the peripheral partial force of each pocket 46 in the main body S1 is formed in the thick portion 47 that is thicker than the radial thickness W2 of the general portion of the main body S1, and the thick portion 47 requires the inner surface of the cage. A large radial width is secured. The general portion of the main body S1 is a portion excluding the peripheral portion of each pocket 46 in the main body S1. The general part of the main body S1 has, for example, a uniform thickness over the entire circumference. The thick part 47 is not provided in the vicinity of the bottom of the pocket 46, and is formed in two parts facing in the circumferential direction. The thick wall portion 47 also has a distal end force of the claw portion 48 extending along the opening edge of the pocket 46, and is connected to the pocket bottom side from the base end of the claw portion 48.

[0055] As can be understood from FIG. 11, the main body S2 and the lid S2 are coupled in a snap-in manner. In the illustrated example, the main body S1 has a convex connector 60 (FIGS. 11, 12a, 12b, and 13), and the lid S2 has a concave connector 62 (FIGS. 11, 18a, 18b, and 13). 19). The reverse relationship, that is, the connector on the lid S2 side may be concave, and the connector on the main body S1 side may be convex.

[0056] The convex connector 60 of the main body S1 extends perpendicularly to the paper surface of FIG. 12a, has a mushroom-shaped cross section, and has a mountain-shaped head and a neck that is narrower than the maximum portion of the head. The concave connector 62 of the lid S2 has a groove 64 that extends perpendicularly to the plane of the paper in FIG. 18b and whose cross-section is complementary to the convex connector 60 of the body S1. A wall 66 is formed at one end of the groove 64. The walls 66 are alternately provided in a staggered manner on the plurality of connectors 62 arranged in the longitudinal direction of the lid S2.

To describe the connector 62 in more detail, as shown in FIG. 19, there is a pair of dividing wall portions 65 with a groove 64 interposed therebetween. The groove 64 is formed deep in the width direction of the lid S2, or the outer wall surface of each dividing wall portion 65 is cut away so that the dividing wall portion 65 is easily elastically deformed. In addition, the inner walls facing each of the dividing wall portions 55 are engaged with the maximum portion of the mountain-shaped head of the connector 60 to prevent it from coming off. A recess 67 for performing the above is formed. When the head of the connector 60 of the main body S1 is pushed into the groove 64 of the connector 62 of the lid S2, the dividing wall portion 65 of the connector 62 expands inertially to allow the connector 60 to enter, At the same time as the maximum part of the mountain head of the connector 62 passes, it is restored by elasticity and is prevented from coming off.

[0058] The lid S2 has an arc portion 68 formed between adjacent connectors 62, and the arc portion 68 forms a part of the outline of the pocket 46 in a state of being coupled to the main body S1 (Fig. 11). reference). The circumferential movement of the rolling element 25 accommodated in the pocket 46 is received exclusively by the rolling element holding surface 50 of the main body S1. For this reason, the rolling element holding surface 50 is reinforced by the thick wall portion 47 described above. On the other hand, since the rolling element 25 and the lid S2 do not interfere with each other in the circumferential direction in the lid S2, the reinforcement as in the thick portion 47 in the main body S1 is omitted.

[0059] When assembling the rolling element 25 and the cage 40, the cage 40 is pushed in, not the rolling element 25. That is, if the end face of the cage 40 opposite to the side where the pocket 46 is open is called the back face 41 (Fig. 12a), the rolling element 25 is placed between the outer ring 24 and the inner ring 23. In the aligned state, the opening of the pocket 46 is aligned with the position of the rolling element 25 and the back surface 41 of the retainer 40 is pushed to accommodate the rolling element 25 in the pocket 46.

Brief Description of Drawings

FIG. 1 is a front view showing an embodiment of a rolling bearing cage according to the present invention.

FIG. 2 is a front view showing another embodiment of the rolling bearing cage according to the present invention.

FIG. 3 shows another embodiment of the rolling bearing retainer according to the present invention, in which a lid member is mounted on the axial opening side of the pocket located at the end of the segment adjacent to the unconnected portion as a separation preventing means. FIG.

[FIG. 4] In another embodiment of the rolling bearing cage according to the present invention, the opening width of the pocket located at the end of the segment adjacent to the non-connecting portion is made smaller than the other pockets as another separation preventing means. FIG.

FIG. 5 shows another embodiment of the rolling bearing retainer according to the present invention, in which the axial length of the pocket peripheral part located at the end of the segment adjacent to the non-connecting part is set as another means for preventing separation. It is a fragmentary top view which shows the example made larger than the pocket peripheral part.

[Fig. 6a] Another embodiment of the rolling bearing retainer according to the present invention is another separation preventing means. FIG. 6 is a partial plan view showing an example in which the thickness of the pocket peripheral portion located at the end portion of the segment adjacent to the non-connecting portion is made larger than that of other pocket peripheral portions.

FIG. 6b is a cross-sectional view taken along line XX of FIG. 6a in another embodiment of the rolling bearing retainer according to the present invention.

7] A partial front view showing an example in which the material of the segment adjacent to the non-connecting portion is made different from other segments as another separation preventing means in another embodiment of the rolling bearing retainer according to the present invention. is there.

[8] FIG. 8 is an enlarged sectional view showing a rolling bearing incorporating the cage shown in FIGS.

FIG. 9 is a partial cross-sectional view showing a state in which a bearing is attached to a base plate via a spacer in a test assuming that an ultra-thin type rolling bearing is mounted on a CT scanner device.

[10a] This is a partial front view illustrating the mechanism before the conventional cage is released, and shows the state before the release.

[10b] This is a partial front view showing the state when the conventional cage is detached, for explaining the mechanism by which the conventional cage is detached.

[10c] This is a partial front view showing the state after the release, for explaining the mechanism by which the conventional cage is released.

[11] FIG. 11 is a developed plan view of a segment constituting the cage in another embodiment of the rolling bearing cage according to the present invention.

FIG. 12a is a developed plan view of a main body constituting the segment of FIG.

FIG. 12b is a front view of the main body of FIG. 12a.

FIG. 13 is a partial perspective view of the main body.

FIG. 14 is a partial front view of the main body.

FIG. 15 is a partial plan view of the main body.

FIG. 16 is a partially enlarged view of FIG.

FIG. 17 is a partial cross-sectional view of FIG.

FIG. 18a is a development plan view of a lid of a segment constituting the cage.

FIG. 18b is a front view of the lid of FIG. 18a.

[FIG. 19] A perspective view of an essential part of the lid. FIG. 20 is a cross-sectional view showing a schematic configuration of a CT scanning apparatus.

FIG. 21 is an enlarged cross-sectional view showing a conventional rolling bearing.

FIG. 22 is a front view showing a conventional rolling bearing retainer.

FIG. 23 is a plan view showing segments constituting the cage of FIG.

FIG. 24 is a partial plan view showing a segment facing a circumferential direction adjacent to a non-connecting portion.

26, 28 Cage

27, 29 Segment Meng

23 Inner ring

24 outer ring

25 Rolling elements

30 Unconnected part

33a, 33b Pocket

34 Edge

35 Removal prevention means (lid member)

LI, LI ', L2 Pocket opening width

HI, H2 axial length

Tl, T2 thickness

40 Cage

41 Rear

S segment

S1 body

42 joint

42a Joint body

42b Mating protrusion

44 Joint

44a Joint body 4b Mating recess 6 Pocket 7 Thick part

8 Nail

0 Rolling element holding surface 2 Circumferential relief 4 Chamfer 6 Crossing oil sump 8 Bottom oil sump 0 Convex connector

S2 lid

2 Concave connector 4 Groove

6 walls

8 Arc part

Claims

The scope of the claims

[1] A rolling bearing retainer composed of a plurality of arc-shaped segments, characterized in that the segments are connected in an annular shape and endless without a non-connecting portion in the circumferential direction. Rolling bearing cage.

[2] The rolling bearing retainer according to claim 1, wherein the segment is made of resin.

[3] The rolling bearing retainer according to claim 2, wherein the resin is PPS (polyphenylene sulfide).

[4] A plurality of arc-shaped segments are annularly formed by connecting them in the circumferential direction, and pockets for accommodating rolling elements are formed at predetermined intervals in the circumferential direction, and the segments are partially formed in the circumferential direction. A rolling bearing retainer having a non-connecting portion, wherein a detachment force of the rolling element is applied to a pocket located at an end of at least one of the circumferentially opposed segments adjacent to the non-connecting portion. A retainer for rolling bearings, characterized in that it is provided with means for preventing separation from being larger than other pockets.

[5] The rolling bearing according to claim 4, wherein the separation preventing means is provided with a lid member on an axial opening side of a pocket located at an end of a segment facing the circumferential direction adjacent to the unconnected portion. Cage.

6. The cage for a rolling bearing according to claim 5, wherein the central force of the pocket is such that the axial distance to the center of gravity of the segment is within 5% of the pocket diameter.

[7] The rolling bearing retainer according to claim 5 or 6, wherein the body is provided with a portion for receiving the rolling elements in the circumferential direction.

[8] The rolling bearing retainer according to any one of claims 5 to 7, wherein the rolling element and the lid do not interfere with each other in the circumferential direction!

[9] The opening prevention of the pocket located in the edge part of the segment which adjoins a non-connecting part and opposes in the circumference direction is made smaller than the opening width of other pockets. Roller bearing cage.

[10] The separation preventing means is configured such that the axial length of the pocket peripheral portion located at the end of the segment facing the circumferential direction adjacent to the unconnected portion is larger than the axial length of the other pocket peripheral portions. The cage for rolling bearings according to claim 4.

11. The disengagement prevention means according to claim 4, wherein the thickness of the pocket peripheral portion located at the end portion of the segment adjacent to the non-connecting portion in the circumferential direction is larger than the thickness of the other pocket peripheral portions. The cage for rolling bearings as described.

[12] The rolling bearing retainer according to claim 4, wherein the disengagement preventing means comprises a segment that is adjacent to the non-connecting portion and that opposes in the circumferential direction with a material having a hardness higher than that of the other segments.

[13] A plurality of rolling elements incorporated between the races of the inner ring, the outer ring, and the inner and outer rings, and the rolling element is predetermined in the circumferential direction by the cage according to any one of claims 1 to 12. Rolling bearings kept at intervals.

14. The rolling device according to claim 13, wherein either one of the outer ring and the inner ring is applied to a rotating base of a CT scanner device that rotates around the subject, and the other is fixed to a fixed base of the CT scanner device. bearing.