Radial thrust bearing
The radial thrust bearing addresses cooling and rolling efficiency issues by incorporating through holes and grooves for lubricant circulation, enhancing performance under dual loads and stabilizing rolling elements.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- NIPPON THOMPSON
- Filing Date
- 2024-11-20
- Publication Date
- 2026-06-01
AI Technical Summary
Existing radial thrust bearings face challenges in efficiently cooling and ensuring smooth rolling of rolling elements, especially when subjected to both radial and thrust loads, which can lead to instability and reduced performance.
A radial thrust bearing design featuring through holes in the outer ring for lubricant supply, axial grooves in the radial cage, and a specialized thrust cage structure that facilitates efficient lubricant circulation and distribution, ensuring stable rolling element orientation and cooling.
The design ensures efficient cooling and smooth rolling of rolling elements by improving lubrication and circulation, allowing the bearing to handle both radial and thrust loads effectively, with enhanced load-bearing capacity and reduced risk of lubricant stagnation.
Smart Images
Figure 2026089235000001_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to a radial thrust bearing.
Background Art
[0002] A thrust needle roller bearing including a cage that holds needle rollers is known (see, for example, Patent Document 1). On the axial side surfaces of the column portions located between the pockets of the cage included in the thrust needle roller bearing disclosed in Patent Document 1, convex portions or concave portions that hinder the flow of lubricating oil are formed.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] Recently, in situations where it is necessary to receive loads in the radial direction and the thrust direction, a radial thrust bearing that can receive both loads has been used. In such a radial thrust bearing, efficient cooling and ensuring smooth rolling of the rolling elements are required.
[0005] Therefore, one of the objectives is to provide a radial thrust bearing that can ensure efficient cooling and smooth rolling of the rolling elements.
Means for Solving the Problems
[0006] A radial thrust bearing according to this disclosure is subjected to radial and thrust loads. The radial thrust bearing comprises a plurality of radial rolling elements subjected to radial loads, a radial cage holding the plurality of radial rolling elements, a plurality of thrust rolling elements subjected to thrust loads, a thrust cage holding the plurality of thrust rolling elements, an outer ring having a first outer ring raceway surface in contact with the rolling surfaces of the radial rolling elements, and an inner ring having a first inner ring raceway surface in contact with the rolling surfaces of the radial rolling elements. The outer ring includes a second outer ring raceway surface in contact with the rolling surfaces of the thrust rolling elements. The inner ring includes a second inner ring raceway surface in contact with the rolling surfaces of the thrust rolling elements. The outer ring is provided with through holes extending from the outside to the raceway regions of the plurality of radial rolling elements. The radial retainer includes a pair of radial annular sections spaced apart in the axial direction, and a plurality of radial column sections spaced apart in the circumferential direction to form radial pockets for accommodating radial rolling elements, and connected to the pair of radial annular sections. The outer diameter surface of the radial column sections is provided with grooves that extend in the axial direction and are recessed toward the inner diameter side. The grooves have openings at at least one end of the radial column section in the axial direction. The thrust retainer includes an inner diameter thrust annular section and an outer diameter thrust annular section spaced apart in the radial direction, and a plurality of thrust column sections spaced apart in the circumferential direction to form thrust pockets for accommodating thrust rolling elements, and connected to the inner diameter thrust annular section and the outer diameter thrust annular section. The inner diameter thrust annular section has a first wall surface located on the side of the radial retainer where the opening is provided in the axial direction. The first wall surface includes a first region where the distance from the radial retainer in the axial direction increases from the inner diameter side to the outer diameter side. [Effects of the Invention]
[0007] According to the radial thrust bearing described above, efficient cooling and smooth rolling of the rolling elements can be ensured. [Brief explanation of the drawing]
[0008] [Figure 1]Figure 1 is a schematic perspective view showing the appearance of a radial thrust bearing in Embodiment 1 of the present disclosure. [Figure 2] Figure 2 is a schematic plan view of the radial thrust bearing shown in Figure 1, viewed from the axial direction. [Figure 3] Figure 3 is a schematic side view of the radial thrust bearing shown in Figure 1, viewed from the outer diameter side. [Figure 4] Figure 4 is a schematic cross-sectional view showing a portion of the radial thrust bearing shown in Figure 1. [Figure 5] Figure 5 is a schematic perspective view showing a portion of the radial thrust bearing shown in Figure 1. [Figure 6] Figure 6 is an exploded view of the radial thrust bearing shown in Figure 1. [Figure 7] Figure 7 is an enlarged view showing a portion of the radial thrust bearing shown in Figure 1. [Figure 8] Figure 8 is an external perspective view showing the radial rollers assembled into the radial cage. [Figure 9] Figure 9 is an enlarged view of the region indicated by IX in the radial retainer shown in Figure 8. [Figure 10] Figure 10 is an enlarged cross-sectional view showing a portion of the radial retainer. [Figure 11] Figure 11 shows a portion of the radial retainer viewed from the outer diameter side. [Figure 12] Figure 12 is a schematic perspective view of the thrust retainer. [Figure 13] Figure 13 is a schematic perspective view of the thrust retainer. [Figure 14] Figure 14 is an enlarged view of the region indicated by XIV in the thrust retainer shown in Figure 12. [Figure 15] Figure 15 is an enlarged view of the region indicated by XV in the thrust retainer shown in Figure 13. [Modes for carrying out the invention]
[0009] [Summary of the Embodiment] The radial thrust bearing of this disclosure is subjected to radial and thrust loads. The radial thrust bearing comprises a plurality of radial rolling elements subjected to radial loads, a radial cage holding the plurality of radial rolling elements, a plurality of thrust rolling elements subjected to thrust loads, a thrust cage holding the plurality of thrust rolling elements, an outer ring having a first outer ring raceway surface in contact with the rolling surfaces of the radial rolling elements, and an inner ring having a first inner ring raceway surface in contact with the rolling surfaces of the radial rolling elements. The outer ring includes a second outer ring raceway surface in contact with the rolling surfaces of the thrust rolling elements. The inner ring includes a second inner ring raceway surface in contact with the rolling surfaces of the thrust rolling elements. The outer ring is provided with through holes extending from the outside to the raceway regions of the plurality of radial rolling elements. The radial retainer includes a pair of radial annular sections spaced apart in the axial direction, and a plurality of radial column sections spaced apart in the circumferential direction to form radial pockets for accommodating radial rolling elements, and connected to the pair of radial annular sections. The outer diameter surface of the radial column sections is provided with grooves that extend in the axial direction and are recessed toward the inner diameter side. The grooves have openings at at least one end of the radial column section in the axial direction. The thrust retainer includes an inner diameter thrust annular section and an outer diameter thrust annular section spaced apart in the radial direction, and a plurality of thrust column sections spaced apart in the circumferential direction to form thrust pockets for accommodating thrust rolling elements, and connected to the inner diameter thrust annular section and the outer diameter thrust annular section. The inner diameter thrust annular section has a first wall surface located on the side of the radial retainer where the opening is provided in the axial direction. The first wall surface includes a first region where the distance from the radial retainer in the axial direction increases from the inner diameter side to the outer diameter side.
[0010] The radial-thrust bearing according to this disclosure includes multiple radial rolling elements that receive radial loads and multiple thrust rolling elements that receive thrust loads, so that both radial and thrust loads can be appropriately received by a single bearing. This makes it possible to miniaturize the bearing. In addition, because it includes a radial cage that holds the radial rolling elements and a thrust cage that holds the thrust rolling elements, the orientation of each rolling element can be stabilized during rolling.
[0011] In the case of radial thrust bearings, the bearing itself may become hot when used near a heat source or due to high-speed rotation. In such cases, cooling of the bearing is necessary to ensure stable rolling of the radial and thrust rolling elements. The outer ring of the radial thrust bearing included in this disclosure is provided with through holes that extend from the outside to the raceway areas of multiple radial rolling elements. These through holes can be used to supply fluid lubricants such as oil air or oil mist into the bearing. Therefore, the cooling and lubrication performance inside the bearing can be improved. The outer diameter surface of the radial column of the radial cage is provided with a groove having an opening at at least one end of the radial column in the axial direction. The groove extends in the axial direction and is recessed inward. This allows lubricant that has reached the outer diameter surface of the radial cage through the through holes to be supplied to the axial opening side using the groove. Furthermore, the inner diameter side thrust annular portion included in the thrust cage has a first wall surface located on the side where the opening of the radial cage is provided. Furthermore, the first wall surface includes a first region where the distance from the radial cage in the axial direction increases from the inner diameter side to the outer diameter side. As a result, the lubricant that reaches the opening from the through hole through the groove reaches the first region included in the first wall surface of the thrust cage. Since the first region has a shape where the distance from the radial cage in the axial direction increases from the inner diameter side to the outer diameter side, the lubricant can be easily flowed toward the outer diameter side where the thrust pocket is located. In other words, the risk of lubricant stagnation near the inner diameter side thrust annular portion is reduced, and it becomes easier to actively circulate the lubricant in the radial and axial directions. With a radial thrust bearing configured in this way, efficient cooling of the inside of the bearing can be achieved by smooth circulation of lubricant inside the bearing using the through hole, groove, opening and first region, and the lubrication performance of the supplied lubricant on the radial rolling elements and thrust rolling elements can be improved. Therefore, the above radial thrust bearing ensures efficient cooling and smooth rolling of the rolling elements.
[0012] In the above radial-thrust bearing, the first region may include an inclined surface which is a plane inclined with respect to the axial direction. By doing so, the lubricant reaching the first region from the opening can be made to easily flow toward the outer diameter side along the inclined surface included in the first region. Therefore, the lubricant can be circulated more smoothly.
[0013] In the above radial-thrust bearing, the outer diameter side end of the first region may reach the region where the thrust pocket is located. By doing so, it becomes easy to smoothly flow the lubricant reaching the first region from the opening to the region where the thrust pocket is located. Therefore, the lubricant can be positively supplied to the region where the thrust pocket is located to promote smooth rolling of the thrust rolling elements.
[0014] In the above radial-thrust bearing, the radial thickness of the inner diameter side thrust annular portion may be thicker than the radial thickness of the outer diameter side thrust annular portion. By doing so, the rigidity of the inner diameter side thrust annular portion can be increased and the possibility of change in dimensions in the vicinity where the first region is provided can be reduced. Therefore, the circulation of the lubricant can be ensured more stably.
[0015] In the above radial-thrust bearing, the first wall surface may be arranged on the inner diameter side of the first region and include a second region facing one of the radial annular portions in the axial direction. The axial gap between one of the radial annular portions and the second region may be 0.1 mm or more and 0.5 mm or less. By doing so, while reducing the possibility of interference between the radial annular portion of the radial cage and the inner diameter side thrust annular portion of the thrust cage, the possibility of the lubricant reaching the opening flowing into the inner diameter side through the above gap can be reduced. Therefore, the lubricant can be circulated more positively in the radial and axial directions.
[0016] In the radial thrust bearing described above, the thrust column portion may include a pair of first portions extending radially and connected radially to the inner diameter thrust annular portion and the outer diameter thrust annular portion, respectively; a second portion extending radially and positioned radially between the inner diameter thrust annular portion and the outer diameter thrust annular portion, closer to the radial cage in the axial direction than the pair of first portions; and a pair of third portions extending at an inclination with respect to the radial direction so as to connect the radial ends of the second portion to the pair of first portions, respectively. By doing so, the lubricant can be more easily passed toward the outer diameter side between the inner diameter thrust annular portion and the outer diameter thrust annular portion. Therefore, the lubricant can be circulated radially more smoothly.
[0017] In the radial thrust bearing described above, the material of the thrust cage may be at least one of SCM steel and copper alloy. Such a thrust cage has high thermal conductivity and rapid heat diffusion, making it easier to avoid localized temperature increases when the bearing temperature rises. Furthermore, it does not soften easily when the temperature rises, and the coefficient of linear expansion is similar when the outer ring and inner ring are made of bearing steel, so the dimensional changes during temperature changes are kept similar among the components, and interference between components and large changes in clearance dimensions can be suppressed.
[0018] In the radial thrust bearing described above, the groove may have an opening only at one end of the column in the axial direction. By doing so, when a heat source is located on one side in the axial direction, the opening of the groove can be positioned on the side where the heat source is located, allowing lubricant to be actively supplied to the heat source side. Therefore, more efficient cooling can be achieved.
[0019] In the radial thrust bearing described above, the multiple thrust rolling elements may be arranged in double rows on both axial ends of the radial rolling elements in the axial direction. A pair of thrust cages may be provided to hold the multiple thrust rolling elements arranged in double rows. In this way, a larger thrust load can be supported by the multiple thrust rolling elements arranged in double rows. Therefore, the load-bearing capacity in the thrust direction can be increased.
[0020] [Specific examples of embodiments] Next, an example of a specific embodiment of the radial thrust bearing of this disclosure will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numeral and their descriptions will not be repeated.
[0021] (Embodiment 1) First, Embodiment 1, which is an embodiment of the present disclosure, will be described. Figure 1 is a schematic perspective view showing the external appearance of the radial thrust bearing in Embodiment 1 of the present disclosure. Figure 2 is a schematic plan view of the radial thrust bearing shown in Figure 1, viewed from the axial direction. Figure 2 is a view from the opposite direction to the arrow Z shown in Figure 1. In Figure 1 and the following figures, the Z direction indicates the axial direction. That is, although not shown, the shaft supported by the radial thrust bearing extends in the Z direction. The X and Y directions indicate the radial directions from the center of the radial thrust bearing when viewed from the axial direction. The X direction is the direction perpendicular to the Y direction in a plane perpendicular to the axial direction. Figure 3 is a schematic side view of the radial thrust bearing shown in Figure 1, viewed from the outer diameter side. Figure 4 is a schematic cross-sectional view showing a part of the radial thrust bearing shown in Figure 1. Figure 4 is a cross-sectional view taken along the XZ plane, excluding the thrust column portion which will be described later. Figure 5 is a schematic perspective view showing a part of the radial thrust bearing shown in Figure 1. Figure 5 shows a cross-section of a radial thrust bearing, including the thrust column. Figure 6 is an exploded view of the radial thrust bearing shown in Figure 1. Figure 7 is an enlarged view of a portion of the radial thrust bearing shown in Figure 1. In Figures 4 and 5, the flow of lubricant is indicated by arrows. The thickness of the arrow indicates the approximate amount of lubricant flowing. That is, a thicker arrow means a larger amount of lubricant is flowing.
[0022] Referring to Figures 1 to 7, the radial thrust bearing 11 according to Embodiment 1 of this disclosure is a bearing capable of receiving both radial and thrust loads. The radial thrust bearing 11 comprises an outer ring 12, an inner ring 13, a plurality of radial rollers 14 as a plurality of radial rolling elements subjected to radial loads, a plurality of thrust rollers 15 as a plurality of thrust rolling elements subjected to thrust loads, a plurality of thrust rollers 16 as a plurality of thrust rolling elements subjected to thrust loads, a radial cage 17 holding the plurality of radial rollers 14, a thrust cage 18 holding the plurality of thrust rollers 15, and a thrust cage 19 holding the plurality of thrust rollers 16. Note that the radial rollers 14, thrust rollers 15, and thrust rollers 16 may all be of the same shape. That is, they are classified as radial rollers 14, thrust rollers 15, or thrust rollers 16 depending on the position in which the rollers are arranged. In this embodiment, the material of the outer ring 12 and inner ring 13 is selected to be, for example, SUJ2, a high-carbon chromium bearing steel. The material of the thrust cage 19 is at least one of SCM steel and copper alloy. In this embodiment, the material of the thrust cage 19 is brass.
[0023] Multiple thrust rollers 15 and multiple thrust rollers 16 are arranged in double rows with spacing in the axial direction. In this embodiment, the multiple thrust rollers 15 and multiple thrust rollers 16 are arranged in double rows on both axial ends of the radial roller 14 in the axial direction. A pair of thrust cages 18 and thrust cages 19 are provided to hold the thrust rollers 15 and thrust rollers 16 arranged in double rows, respectively. A radial thrust bearing 11 with this configuration can withstand larger thrust loads with the multiple thrust rollers 15 and multiple thrust rollers 16 arranged in double rows. Therefore, the load capacity in the thrust direction can be increased.
[0024] The outer ring 12 is disc-shaped with a hole that penetrates it axially located in the radial center. The inner diameter surface of the outer ring 12 forms a first outer ring raceway surface 31 that contacts the rolling surface 21 of the radial rollers 14. In other words, the outer ring 12 has a first outer ring raceway surface 31 that contacts the rolling surface 21 of the radial rollers 14. The outer ring 12 has multiple mounting holes 32 that penetrate it axially and are spaced apart in the circumferential direction. In other words, the mounting holes 32 extend from one end face 33 to the other end face 34 in the axial direction of the outer ring 12. These mounting holes 32 are round and are used for attaching the outer ring 12 to other components, etc.
[0025] The outer ring 12 is provided with through holes 35 that extend from the outside to the raceway areas of multiple radial rollers 14. Multiple through holes 35 are provided at intervals in the circumferential direction. The through holes 35 are also called lubrication holes and are provided to have openings in the outer diameter surface 36 of the outer ring 12. The through holes 35 are provided to penetrate radially. The walls constituting the through holes 35 are provided straight in the radial direction. Multiple through holes 35 are provided with their positions offset from the mounting holes 32 in the circumferential direction. That is, when viewed in the axial direction, the positions of the mounting holes 32 and the positions of the through holes 35 are offset in the circumferential direction. The through holes 35 are also round. The diameter of the through holes 35 is smaller than the diameter of the mounting holes 32. These through holes 35 are used to supply lubricants such as oil air or oil mist into or out of the radial thrust bearing 11 for cooling and lubrication. The ratio of through-holes 35 used for supplying oil-air to through-holes 35 used for exhausting oil-air can be arbitrarily adjusted based on cooling performance, lubrication performance, the amount of heat emitted from the heat source, etc.
[0026] The outer ring 12 includes a second outer ring raceway surface 37 that contacts the rolling surface 22 of the thrust roller 15. The outer ring 12 also includes a second outer ring raceway surface 38 that contacts the rolling surface 23 of the thrust roller 16. The second outer ring raceway surface 37 and the second outer ring raceway surface 38 are spaced apart in the axial direction.
[0027] The inner ring 13 is composed of two raceway rings 41 and 42. Both the first raceway ring 41 and the second raceway ring 42 are disc-shaped with axially penetrating holes 48 and 49 located in the radial center. The first raceway ring 41 and the second raceway ring 42 are combined so as to be in contact in the axial direction. The radial thrust bearing 11 supports a shaft (not shown) located in the inner diameter holes 48 and 49 of the inner ring 13. A portion of the outer diameter surface of the first raceway ring 41 becomes the first inner ring raceway surface 43, which is in contact with the rolling surface 21 of the radial rollers 14. That is, the inner ring 13 has a first inner ring raceway surface 43 that is in contact with the rolling surface 21 of the radial rollers 14. The radial space between the first outer ring raceway surface 31 and the first inner ring raceway surface 43 becomes the raceway region on which the multiple radial rollers 14 roll.
[0028] The first raceway 41 includes a second inner raceway surface 44 that contacts the rolling surface 22 of the thrust roller 15. The second raceway 42 includes a second inner raceway surface 45 that contacts the rolling surface 23 of the thrust roller 16. The second inner raceway surface 44 and the second inner raceway surface 45 are arranged to face each other in the axial direction. The axial space between the second outer raceway surface 37 and the second inner raceway surface 44 becomes the raceway region on which the multiple thrust rollers 15 roll. The axial space between the second outer raceway surface 38 and the second inner raceway surface 45 becomes the raceway region on which the multiple thrust rollers 16 roll.
[0029] The first raceway 41 is provided with connecting holes 46 that penetrate in the axial direction. Multiple connecting holes 46 are provided at intervals in the circumferential direction. The connecting holes 46 are located on the inner diameter side of the second inner raceway surface 44. The second raceway 42 is provided with connecting holes 47 that penetrate in the axial direction. Multiple connecting holes 47 are provided at intervals in the circumferential direction. The connecting holes 47 are located on the inner diameter side of the second inner raceway surface 45. The circumferential spacing of the connecting holes 47 is the same as the circumferential spacing of the connecting holes 46. The first raceway 41 and the second raceway 42 can be connected by bolts using the connecting holes 46 and 47.
[0030] A thrust retainer 18, which holds multiple thrust rollers 15, is positioned between the second outer ring raceway surface 37 and the second inner ring raceway surface 44. The thrust retainer 18 is disc-shaped and has pockets for holding multiple thrust rollers 15 that are spaced apart in the circumferential direction. A thrust retainer 19, which holds multiple thrust rollers 16, is positioned between the second outer ring raceway surface 38 and the second inner ring raceway surface 45. The thrust retainer 19 has thrust pockets for holding multiple thrust rollers 16 that are spaced apart in the circumferential direction.
[0031] Next, the configuration of the radial cage 17 will be described. Figure 8 is an external perspective view showing the radial cage 17 with the radial rollers 14 assembled. Figure 9 is an enlarged view of the region indicated by IX in the radial cage 17 shown in Figure 8. Figure 10 is an enlarged cross-sectional view showing a part of the radial cage 17. Figure 10 is a cross-sectional view when cut in the XY plane. Figure 11 is a view of a part of the radial cage 17 from the outer diameter side.
[0032] Referring to Figures 8 to 11, the radial retainer 17 holds a plurality of radial rollers 14. The radial retainer 17 includes radial annular sections 51 and 52, and a plurality of radial column sections 53, which are spaced apart in the axial direction. The radial annular sections 51 and 52 are provided in pairs. Each of the plurality of radial column sections 53 has an axially extending shape and is connected to the pair of radial annular sections 51 and 52. The plurality of radial column sections 53 are spaced apart in the circumferential direction to form radial pockets 54 that accommodate the radial rollers 14. Each radial pocket 54 accommodates one radial roller 14. The radial column sections 53 have protruding regions 55 and 56 on the outer and inner diameter sides of the pair of radial annular sections 51 and 52, respectively, that protrude toward the side where the radial pockets 54 are located. These protruding regions 55 and 56 prevent the radial rollers 14 housed in the radial pocket 54 from falling out. The radial rollers 14 are housed in the radial pocket 54 by elastically deforming either of the protruding regions 55 or 56 and pushing them radially into place.
[0033] Here, the outer diameter surface 57 of the radial column portion 53 is provided with a groove portion 61 that extends in the axial direction and is recessed toward the inner diameter side. A groove portion 61 is provided in each radial column portion 53. The groove portion 61 has an opening 62 at at least one end of the radial column portion 53 in the axial direction. In this embodiment, the groove portion 61 has an opening 62 only at one end of the radial column portion 53 in the axial direction. The wall surface 63 constituting the groove portion 61 includes an arc-shaped curved surface when viewed in the axial direction. In this embodiment, the wall surface 63 constituting the groove portion 61 is a semi-circular curved surface when viewed in the axial direction. Furthermore, the wall surface 64 on the other axial side constituting the groove portion 61 includes a part of a sphere. In this embodiment, the wall surface 64 on the other axial side constituting the groove portion 61 is a part of a sphere. The circumferential width of the groove portion 61, the radial depth, the position where the closed groove portion 61 is formed, etc., can be set arbitrarily.
[0034] Next, the configuration of the thrust cage 18 will be described. Figures 12 and 13 are schematic perspective views of the thrust cage 18, respectively. Figure 12 shows the view in the opposite direction to that indicated by arrow Z, and Figure 13 shows the view in the direction indicated by arrow Z. Figure 14 is an enlarged view of the region indicated by XIV in the thrust cage 18 shown in Figure 12. Figure 15 is an enlarged view of the region indicated by XV in the thrust cage 18 shown in Figure 13. Note that the configuration of the thrust cage 19 is the same as that of the thrust cage 18, so its explanation will be omitted. The thrust cage 19 is incorporated into the radial thrust bearing 11 with its orientation in the Z direction reversed from that of the thrust cage 18.
[0035] Referring in conjunction with Figures 12 to 15, and particularly with Figures 4 and 5, the thrust retainer 18 includes an inner diameter thrust annular portion 71, an outer diameter thrust annular portion 72, and a plurality of thrust column portions 73. The diameter of the inner diameter thrust annular portion 71 is shorter than the diameter of the outer diameter thrust annular portion 72. The radial thickness of the inner diameter thrust annular portion 71 is greater than the radial thickness of the outer diameter thrust annular portion 72. Each of the plurality of thrust column portions 73 is radially extending and is connected to the inner diameter thrust annular portion 71 on the inner diameter side and to the outer diameter thrust annular portion 72 on the outer diameter side. The plurality of thrust column portions 73 are spaced apart in the circumferential direction to form thrust pockets 74 for accommodating thrust rollers 15. Each thrust pocket 74 accommodates one thrust roller 15.
[0036] The thrust column 73 includes a pair of first parts 75 and 76, a second part 77, and a pair of third parts 78 and 79. The pair of first parts 75 and 76 each extend radially. The first part 75 is connected to the inner diameter thrust annular part 71. Specifically, the inner diameter end of the first part 75 is connected to the inner diameter thrust annular part 71. The first part 76 is connected to the outer diameter thrust annular part 72. Specifically, the outer diameter end of the first part 76 is connected to the outer diameter thrust annular part 72. The second part 77 is positioned radially between the inner diameter thrust annular part 71 and the outer diameter thrust annular part 72. The second part 77 is also positioned closer to the radial retainer 17 in the axial direction than the pair of first parts 75 and 76.
[0037] The pair of third sections 78 and 79 each extend at an inclination with respect to the radial direction. The inclination directions of the third sections 78 and 79 are opposite. The pair of third sections 78 and 79 each connect the radial ends of the second section 77 to the pair of first sections 75 and 76. Specifically, the inner diameter end of the third section 78 is connected to the outer diameter end of the first section 75. The outer diameter end of the third section 78 is connected to the inner diameter end of the second section 77. The inner diameter end of the third section 79 is connected to the outer diameter end of the second section 77. The outer diameter end of the third section 79 is connected to the inner diameter end of the first section 76. That is, the thrust column section 73 is arranged in the order of first section 75, third section 78, second section 77, third section 79, and first section 76 from the inner diameter side.
[0038] The thrust retainer 18 is a so-called M-type retainer. In the second part 77, the thrust retainer 18 prevents the thrust roller 15 housed in the thrust pocket 74 from falling out in the axial direction, specifically from falling out toward the side where the radial retainer 17 is located in the axial direction. In the first parts 75 and 76, the thrust retainer 18 prevents the thrust roller 15 housed in the thrust pocket 74 from falling out in the axial direction, specifically from falling out toward the side opposite to where the radial retainer 17 is located in the axial direction.
[0039] Here, the inner diameter thrust annular portion 71 of the thrust retainer 18 includes a first wall surface 81 located on the radial retainer 17 side in the axial direction, and a second wall surface 82 located on the opposite side from the radial retainer 17 side. The first wall surface 81 includes a first region 83 and a second region 84 located on the inner diameter side of the first region 83. The second region 84 faces one of the radial annular portions 51 in the axial direction.
[0040] In the first region 83, the distance from the radial retainer 17 in the axial direction increases from the inner diameter side to the outer diameter side. In this embodiment, the first region 83 includes an inclined surface which is a plane inclined with respect to the axial direction. Furthermore, the axial thickness of the inner diameter side thrust annular portion 71 gradually decreases from the inner diameter side to the outer diameter side in the region where the first region 83 is located. That is, in the region where the first region 83 is located, the axial length between the first wall surface 81 and the second wall surface 82 gradually decreases from the inner diameter side to the outer diameter side. The outer diameter side end of the first region 83 reaches the region where the thrust pocket 74 is located. With this configuration, a relatively wide space is formed between the first region 83 and the radial column portion 53 of the radial retainer 17. The axial gap G between one of the radial annular portions 51 and the second region 84 is 0.1 mm or more and 0.5 mm or less (see Figure 4 in particular).
[0041] With a radial thrust bearing 11 configured in this way, since it includes multiple radial rollers 14 that receive radial loads and multiple thrust rollers 15 and 16 that receive thrust loads, it can appropriately receive both radial and thrust loads with a single bearing. This allows for a smaller bearing size. Furthermore, since it includes a radial cage 17 that holds the radial rollers 14, a thrust cage 18 that holds the thrust rollers 15, and a thrust cage 19 that holds the thrust rollers 16, the orientation of each roller can be stabilized during rolling.
[0042] In the case of the radial thrust bearing 11, the bearing itself may become hot when used near a heat source or due to high-speed rotation. In such cases, the bearing needs to be cooled in order to ensure stable rolling of the radial rollers 14, thrust rollers 15, and thrust rollers 16. The outer ring 12 included in the radial thrust bearing 11 of this disclosure is provided with through holes 35 that extend from the outside to the raceway areas of the multiple radial rollers 14. These through holes 35 can be used to supply fluid lubricants such as oil air or oil mist into the bearing. Therefore, the cooling and lubrication performance inside the bearing can be improved. The outer diameter surface 57 of the radial column portion 53 of the radial cage 17 is provided with a groove portion 61 having an opening 62 at one end of the radial column portion 53 in the axial direction. The groove portion 61 extends in the axial direction and is recessed inward. This allows lubricant that has passed through the through holes 35 to the outer diameter surface of the radial cage 17 to be supplied to the axial opening 62 side using the groove portion 61. Furthermore, the inner diameter thrust annular portion 71 included in the thrust retainer 18 has a first wall surface 81 located on the side where the opening 62 of the radial retainer 17 is provided. The first wall surface 81 includes a first region 83 in which the distance from the radial retainer 17 in the axial direction increases from the inner diameter side to the outer diameter side. As a result, the lubricant that reaches the opening 62 from the through hole 35 through the groove 61 reaches the first region 83 included in the first wall surface 81 of the thrust retainer 18. Because the first region 83 has a shape in which the distance from the radial retainer 17 in the axial direction increases from the inner diameter side to the outer diameter side, the lubricant can be easily flowed toward the outer diameter side where the thrust pocket 74 is located. In other words, the risk of lubricant stagnation near the inner diameter thrust annular portion 71 is reduced, and it becomes easier to actively circulate the lubricant in the radial and axial directions. With a radial thrust bearing 11 configured in this way, the smooth circulation of lubricant within the bearing using the through-hole 35, groove 61, opening 62, and first region 83 allows for efficient cooling of the inside of the bearing, thereby improving the lubrication performance of the supplied lubricant on the radial rollers 14, thrust rollers 15, and thrust rollers 16.Based on the above, the radial thrust bearing 11 ensures efficient cooling and smooth roller movement.
[0043] In this embodiment, the first region 83 includes an inclined surface which is a plane inclined with respect to the axial direction. Therefore, the lubricant that has reached the first region 83 from the opening 62 can easily flow outward along the inclined surface included in the first region 83. Thus, the lubricant can be circulated more smoothly.
[0044] In this embodiment, the outer diameter end of the first region 83 extends to the region where the thrust pocket 74 is located. Therefore, it becomes easy to smoothly flow the lubricant that has reached the first region 83 from the opening 62 to the region where the thrust pocket 74 is located. Consequently, it is possible to actively supply lubricant to the region where the thrust pocket 74 is located to promote the smooth rolling of the thrust roller 15.
[0045] In this embodiment, the radial thickness of the inner diameter thrust annular portion 71 is greater than the radial thickness of the outer diameter thrust annular portion 72. Therefore, the rigidity of the inner diameter thrust annular portion 71 can be increased, and the risk of changes in the dimensions near where the first region 83 is provided can be reduced. Consequently, more stable circulation of the lubricant can be ensured.
[0046] In this embodiment, the first wall surface 81 is positioned on the inner diameter side of the first region 83 and includes a second region 84 that faces one of the radial annular portions 51 in the axial direction. The axial gap G between one of the radial annular portions 51 and the second region 84 is 0.1 mm or more and 0.5 mm or less. Therefore, the risk of interference between the radial annular portion 51 of the radial retainer 17 and the inner diameter side thrust annular portion 71 of the thrust retainer 18 can be reduced, while the risk of lubricant reaching the opening 62 flowing into the inner diameter side through the gap can be reduced. Thus, the lubricant can be circulated more actively in the radial and axial directions.
[0047] In this embodiment, the thrust column portion 73 includes a pair of first portions 75 and 76 that extend radially and are connected radially to the inner diameter thrust annular portion 71 and the outer diameter thrust annular portion 72, respectively; a second portion 77 that extends radially and is positioned radially between the inner diameter thrust annular portion 71 and the outer diameter thrust annular portion 72, closer to the radial retainer 17 in the axial direction than the pair of first portions 75 and 76; and a pair of third portions 78 and 79 that extend at an inclination with respect to the radial direction so as to connect the radial ends of the second portion 77 to the pair of first portions 75 and 76, respectively. With a thrust retainer 18 configured in this way, lubricant can easily pass toward the outer diameter side between the inner diameter thrust annular portion 71 and the outer diameter thrust annular portion 72. Therefore, the lubricant can be circulated more smoothly in the radial direction.
[0048] In this embodiment, the material of the thrust retainer 18 is at least one of SCM steel and copper alloy. Such a thrust retainer 18 has high thermal conductivity and rapid thermal diffusion, making it easier to avoid localized temperature increases when the bearing temperature rises. Furthermore, it does not soften easily when the temperature rises, and has a similar coefficient of linear expansion when the outer ring 12 and inner ring 13 are made of bearing steel, so that dimensional changes during temperature changes are kept similar among the components, and interference between components and large changes in clearance dimensions can be suppressed.
[0049] In this embodiment, the groove 61 has an opening 62 only at one axial end of the radial column 53. Therefore, when a heat source is located on one axial side, the opening 62 of the groove 61 can be positioned on the side where the heat source is located, allowing lubricant to be actively supplied to the heat source side. Thus, more efficient cooling can be achieved.
[0050] In this embodiment, the wall surface 63 constituting the groove 61 includes an arc-shaped curved surface when viewed in the axial direction. Therefore, the lubricant supplied through the through hole 35 is smoothly discharged from the groove 61 in the axial direction, reducing the risk of lubricant remaining in the groove 61. Thus, more efficient cooling and smoother roller rolling can be ensured.
[0051] In this embodiment, the groove 61 has an opening 62 only at one axial end of the radial column 53. Therefore, when a heat source is located on one axial side, the opening 62 of the groove 61 is positioned on the side where the heat source is located, allowing lubricant to be actively supplied to the heat source side. Thus, more efficient cooling can be achieved.
[0052] In this embodiment, the wall surface 64 on the axial side of the groove 61 includes a part of a sphere. Therefore, the risk of lubricant remaining in the groove 61 in the closed region of the groove 61 can be reduced. Thus, more efficient cooling and smoother roller rolling can be ensured.
[0053] In this embodiment, the wall surface constituting the through hole 35 is provided straight in the radial direction. Therefore, resistance when supplying lubricant into the bearing can be reduced. Consequently, lubricant can be smoothly supplied from the outside to the raceway region of the radial roller 14.
[0054] (Other embodiments) In the above embodiment, the groove may be configured to have openings at both axial ends of the column. This allows lubricant to be supplied to both axial ends of the column. Therefore, it becomes easier to supply lubricant to the entire inside of the bearing, thereby improving cooling and lubrication performance. Such a configuration is suitable, for example, when a heat source is not located in only one of the axial directions.
[0055] Furthermore, in the above embodiment, the wall surface constituting the through hole is provided straight in the radial direction, but this is not limited to this. For example, the wall surface constituting the through hole may be tapered so that the outer diameter side is larger. By doing so, lubricant can be supplied to the groove with force, and the lubricant can be supplied to the inside of the bearing quickly.
[0056] In the above embodiment, the multiple thrust rollers are arranged in two rows, but the invention is not limited to this configuration, and the multiple thrust rollers may also be arranged in a single row.
[0057] Furthermore, although rollers were used as rolling elements in the above embodiment, the invention is not limited to this, and balls may also be used as rolling elements.
[0058] In the above embodiment, the first region is an inclined surface which is a plane that is inclined with respect to the axial direction, but it is not limited to this, and the first region may be an arc shape. By doing so, the oil-air can be circulated smoothly.
[0059] Furthermore, in the above embodiment, the outer diameter end of the first region extends to the region where the thrust pocket is located. However, the configuration is not limited to this, and the outer diameter end of the first region may not extend to the region where the thrust pocket is located.
[0060] The embodiments disclosed herein should be understood to be illustrative in all respects and not restrictive in any way. The scope of the present invention is defined by the claims and is intended to include all modifications in the sense and scope equivalent to the claims. [Explanation of Symbols]
[0061] 11 Radial thrust bearing, 12 Outer ring, 13 Inner ring, 14 Radial roller, 15,16 Thrust roller, 17 Radial cage, 18,19 Thrust cage, 21,22,23 Rolling surface, 24,25,26 Arrow, 31 First outer ring raceway surface, 32 Mounting hole, 33,34 End face, 35 Through hole, 36,57 Outer diameter surface, 37,38 Second outer ring raceway surface, 41 Raceway ring (first raceway ring), 42 Raceway ring (second raceway ring), 43 First inner ring raceway surface, 44,45 Second inner ring raceway surface, 46,47 Connecting hole, 48,49 Hole, 51,52 Radial annular section, 53 Radial column section, 54 Radial pocket, 55,56 Protruding region, 61 Groove section, 62 Opening, 63,64 Wall surface, 71 Inner diameter thrust annular section, 72 Outer diameter thrust annular section, 73 Thrust column section, 74 Thrust pocket, 75, 76 First section, 77 Second section, 78, 79 Third section, 81 First wall surface, 82 Second wall surface, 83 First region, 84 Second region.
Claims
1. A radial-thrust bearing that receives radial and thrust loads, Multiple radial rolling elements subjected to radial loads, A radial retainer that holds the plurality of radial rolling elements, Multiple thrust rolling elements subjected to a thrust load, A thrust retainer that holds the plurality of thrust rolling elements, An outer ring having a first outer ring raceway surface that contacts the rolling surface of the radial rolling element, The inner ring comprises an inner ring having a first inner ring raceway surface that contacts the rolling surface of the radial rolling element, The outer ring includes a second outer ring raceway surface that contacts the rolling surface of the thrust rolling element. The inner ring includes a second inner ring raceway surface that contacts the rolling surface of the thrust rolling element. The outer ring is provided with through holes that extend from the outside to the raceway regions of the plurality of radial rolling elements. The radial retainer is, A pair of radial annular sections arranged at intervals in the axial direction, It includes a plurality of radial column portions that are spaced apart in the circumferential direction to form radial pockets for housing the radial rolling elements, and are connected to the pair of radial annular portions, The outer diameter surface of the radial column portion is provided with a groove that extends in the axial direction and is recessed toward the inner diameter side. The groove portion has an opening at at least one end of the radial column portion in the axial direction. The thrust retainer is, An inner diameter thrust annular portion and an outer diameter thrust annular portion are arranged with a gap in the radial direction, It includes a plurality of thrust column portions that are spaced apart in the circumferential direction to form thrust pockets for housing the thrust rolling elements, and which are connected to the inner diameter thrust annular portion and the outer diameter thrust annular portion, The inner diameter thrust annular portion has a first wall surface located in the axial direction on the side of the radial retainer where the opening is provided. A radial thrust bearing wherein the first wall surface includes a first region in which the distance from the radial cage in the axial direction increases from the inner diameter side to the outer diameter side.
2. The radial thrust bearing according to claim 1, wherein the first region includes an inclined surface which is a plane inclined with respect to the axial direction.
3. The radial thrust bearing according to claim 1 or claim 2, wherein the outer diameter end of the first region extends to the region where the thrust pocket is located.
4. The radial thrust bearing according to claim 1 or claim 2, wherein the radial thickness of the inner diameter thrust annular portion is greater than the radial thickness of the outer diameter thrust annular portion.
5. The first wall surface is located on the inner diameter side of the first region and includes a second region facing one of the radial annular portions in the axial direction. The radial thrust bearing according to claim 1 or claim 2, wherein the axial gap between one of the radial annular portions and the second region is 0.1 mm or more and 0.5 mm or less.
6. The aforementioned thrust column section is Each of the following first portions extends radially and is connected to the inner diameter thrust annular portion and the outer diameter thrust annular portion, A second portion extending radially, positioned radially between the inner diameter thrust annular portion and the outer diameter thrust annular portion, and closer to the radial retainer in the axial direction than the pair of first portions, A radial thrust bearing according to claim 1 or 2, comprising a pair of third portions that extend at an inclination with respect to the radial direction so as to connect the radial ends of the second portion to the pair of first portions, respectively.
7. The radial thrust bearing according to claim 1 or claim 2, wherein the material of the thrust retainer is at least one of SCM steel and copper alloy.
8. The radial thrust bearing according to claim 1 or claim 2, wherein the groove portion has an opening only at one axial end of the radial column portion.
9. The plurality of thrust rolling elements are arranged in double rows on both ends of the radial rolling element in the axial direction. The radial thrust bearing according to claim 1 or 2, wherein the thrust retainer is provided in a pair to hold the plurality of thrust rolling elements arranged in double rows.