Angular contact ball bearing

Abstract

To provide an angular contact ball bearing that ensures a certain level of strength of a holder even under high load capacity and high speed rotation to prolong its service life.SOLUTION: An angular contact ball bearing 1 comprises an inner ring 2, an outer ring 3, a plurality of balls 4, and a holder 5. The holder 5 has: a small annular part 6 located radially between a counterbore part 2b of the inner ring 2 and a shoulder part 3d of the outer ring 3; a large annular part 7 located radially between a counterbore part 3b of the outer ring 3 and a shoulder part 2d of the inner ring 2; and pillar parts 8 that connect the small annular part 6 and the large annular part 7 and are provided at multiple locations in a circumferential direction. The small annular part 6, the large annular part 7, and the pillar parts 8 form a pocket Pt that holds the plurality of balls 4. When a radial thickness of the small annular part 6 is T1, a radial thickness of the large annular part 7 is T2, and a diameter of the ball 4 is Da, the followings are satisfied: 0.170≤T1 / Da≤0.280; 0.170≤T2 / Da≤0.280; 0.90≤T1 / T2≤0.10.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an angular contact ball bearing for use in, for example, compressors, pumps, injection molding machines, and the like. [Background technology]

[0002] Patent Document 1 discloses an angular contact ball bearing that does not generate abnormal noise, vibration, or temperature rise and satisfies relationships defined in relation to the internal design of the bearing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-24610 Summary of the Invention [Problem to be solved by the invention]

[0004] Angular contact ball bearings used in compressors, pumps, injection molding machines, etc. are required to have high load capacity and high rotation speed. In conventional angular contact ball bearings, the pocket clearance A of the cage 50 is controlled as shown in Figure 5 to prevent abnormal noise, vibration, and temperature rise. However, when angular contact ball bearings are used with a large load capacity and at high speeds, the cage is also subjected to load, so it is necessary to provide the cage with a certain level of strength.

[0005] An object of the present invention is to provide an angular contact ball bearing having a longer life by ensuring a certain level of cage strength even under high load capacity and high speed rotation. [Means for solving the problem]

[0006] The angular ball bearing of the present invention is an angular ball bearing including an inner ring and an outer ring each having a counterbore portion, a plurality of balls interposed between the inner ring and the outer ring, and a cage that holds the balls, the cage has a small annular portion located radially between a counterbore portion of the inner ring and a shoulder portion of the outer ring, a large annular portion located radially between the counterbore portion of the outer ring and a shoulder portion of the inner ring, and pillar portions connecting the small annular portion and the large annular portion and provided at a plurality of positions in the circumferential direction, the small annular portion, the large annular portion and the pillar portions forming a pocket for holding the plurality of balls, When the radial thickness of the small annular portion is T1, the radial thickness of the large annular portion is T2, and the diameter of the ball is Da, 0.170≦T1 / Da≦0.280 0.170≦T2 / Da≦0.280 The relationship 0.90≦T1 / T2≦1.10 is satisfied. The above T1 refers to the radial thickness of the axially outer portion of the small annular portion. The above T2 refers to the radial thickness of the axially outer portion of the large annular portion. The shoulder of the outer ring is the inner periphery on the back side of the outer ring. The shoulder of the inner race is the outer periphery on the back side of the inner race.

[0007] According to this configuration, for a cage with an asymmetric cross section, T1 / Da, which is the radial thickness T1 of the small annular portion divided by the ball diameter Da, and T2 / Da, which is the radial thickness T2 of the large annular portion divided by the ball diameter Da, are set within the above ranges. This ensures that the cage has a certain level of strength and prevents interference between the cage and at least one of the inner and outer raceways. Furthermore, by controlling T1 / T2, obtained by dividing the radial thickness T1 of the small annular portion by the radial thickness T2 of the large annular portion, within the above range, it is possible to maintain a balance in the thicknesses of the small annular portion and the large annular portion and suppress the cage from whirling during high-speed rotation. As a result, the cage can maintain a certain level of strength even under high load capacity and high-speed rotation, resulting in an angular contact ball bearing with a longer life.

[0008] When the contact angle is equal to or greater than 30 degrees and equal to or less than 45 degrees, the outer diameter of the outer ring is D, and the inner diameter of the inner ring is d, the following relationship may hold: 0.62≦2Da / (Dd)≦0.80 When the contact angle is set to 30 degrees or more and 45 degrees or less, the load capacity is higher than that of angular contact ball bearings with contact angles of, for example, 15 degrees or 25 degrees. Also, from the above relational expression, balls having a relatively large diameter Da relative to the outer diameter D of the outer ring and the inner diameter d of the inner ring are used. This allows the angular contact ball bearing to have an even higher load capacity.

[0009] When the radial clearance between the ball surface and the surface of the ball in the pocket of the retainer facing the ball when the axial center axis of the entire angular contact ball bearing and the axial center axis of the retainer are overlapping, and PCD is the pitch circle diameter of the ball, the following relationship may hold. A / Da≦0.020 2A / PCD≦0.010

[0010] In this case, by appropriately adjusting the clearance A with respect to the ball diameter Da and pitch circle diameter PCD, the amount of cage movement during operation of the angular contact ball bearing becomes appropriate. This ensures the stability of the cage during bearing operation. When the clearance A is controlled as described above, the occurrence of speed differences between the inner and outer rings and the balls is suppressed. This is because the rotation of the balls is not suppressed and the ball rotation speed does not decrease. As a result, the occurrence of abnormal noise, vibration, and temperature rises between the inner and outer rings and the balls due to the speed differences between the inner and outer rings and the balls can be stably suppressed.

[0011] When the circumferential width of the column portion is T3 and the pitch circle diameter of the ball is PCD, the following relationship may be established. 0.01≦T3 / PCD≦0.05 If T3 / PCD, calculated by dividing the column width T3 by the pitch circle diameter PCD, is less than 0.01, the strength of the cage may be insufficient. If T3 / PCD is more than 0.05, the load capacity may be small. By keeping T3 / PCD within the above range, the strength of the cage is ensured, and an angular contact ball bearing can be produced without reducing the ball diameter or the number of balls. Effect of the Invention

[0012] The angular contact ball bearing of the present invention, for a cage with an asymmetric cross section, satisfies 0.170≦T1 / Da≦0.280, 0.170≦T2 / Da≦0.280 and 0.90≦T1 / T2≦1.10, where T1 is the radial thickness of the small annular portion, T2 is the radial thickness of the large annular portion and Da is the diameter of the balls. As a result, the strength of the cage can be secured to a certain level even under high load capacity and high speed rotation, resulting in an angular contact ball bearing with a longer life. [Brief description of the drawings]

[0013] [Figure 1] 1 is a vertical sectional view of an angular ball bearing according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view of a retainer of the angular contact ball bearing. [Diagram 3] FIG. 2 is an enlarged cross-sectional view of a main part of the cage. [Figure 4] 2 is a cross-sectional view of the cage taken along a plane perpendicular to the axial direction. FIG. [Diagram 5] FIG. 11 is a partially enlarged cross-sectional view of a cage in a conventional angular contact ball bearing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] [First embodiment] An angular contact ball bearing according to an embodiment of the present invention will be described with reference to Figures 1 to 4. This angular contact ball bearing is used in, for example, compressors, pumps, injection molding machines, etc. However, the angular contact ball bearing is not limited to these applications and can be applied to various industrial machines, etc. In this specification, the angular contact ball bearing may be simply referred to as a "bearing".

[0015] <Overall structure of angular contact ball bearing> 1, an angular contact ball bearing 1 includes an inner ring 2 and an outer ring 3 which are raceways, a number of balls 4 interposed between a raceway surface 2a of the inner ring 2 and a raceway surface 3a of the outer ring 3, and a cage 5 in which pockets Pt are formed for holding these balls 4. A contact angle α is formed between the raceway surfaces 2a, 3a of the inner and outer rings 2, 3.

[0016] The inner and outer rings 2, 3 are made of, for example, high carbon chromium bearing steel such as SUJ2 or martensitic stainless steel. The balls 4 are made of, for example, steel balls or ceramics. The cage 5 is formed in an annular shape from, for example, nylon reinforced with glass fiber or carbon fiber, PPS, PEEK, or a resin such as a phenolic resin. In this specification, the "axial direction" refers to the direction along the bearing center line AX of the angular ball bearing 1. The "radial direction" refers to the direction perpendicular to the straight line that forms the "axial direction."

[0017] The raceway surface 3a is connected to the front surface of the outer ring 3 via a counterbore portion 3b described later. The front surface of the outer ring 3 represents the side surface that does not support an axial load. The back surface 3c of the outer ring 3 represents the side surface that supports an axial load. A shoulder portion 3d, which is the inner peripheral surface on the back surface side of the outer ring 3, is located radially inward from the counterbore portion 3b of the outer ring 3. The raceway surface 2a is connected to the front surface of the inner ring 2 via a counterbore portion 2b described later. The front surface of the inner ring 2 represents the side surface that does not support an axial load. The back surface 2c of the inner ring 2 represents the side surface that supports an axial load. The inner peripheral surface on the back surface side of the inner ring 2 is called a shoulder portion 2d. The shoulder portion 2d is formed between the raceway surface 2a of the inner ring 2 and the back surface 2c of the inner ring 2. The shoulder portion 2d of the inner ring 2 is located radially outward from the counterbore portion 2b of the inner ring 2.

[0018] The shoulder 3d of the outer ring 3 is formed in a cylindrical surface shape parallel to the axial direction. The counterbore 3b of the outer ring 3 is formed in a cylindrical surface shape or a tapered surface shape formed with a predetermined dimension larger diameter radially outward than the shoulder 3d, and is also called the "shoulder drop portion" of the outer ring 3. The tapered surface is a tapered surface that inclines radially inward from the front side of the outer ring toward the raceway surface 3a. The shoulder 2d of the inner ring 2 is formed in a cylindrical surface shape parallel to the axial direction. The counterbore 2b of the inner ring 2 is formed in a cylindrical surface or a tapered surface shape formed with a predetermined dimension smaller diameter radially inward than the shoulder 2d, and is also called the "shoulder drop portion" of the inner ring 2. The tapered surface is a tapered surface that inclines radially outward from the front side of the inner ring toward the raceway surface 2a.

[0019] <About the cage> As shown in Figures 2 and 3, the cage 5 has a small annular portion 6, a large annular portion 7, and pillar portions 8. This cage 5 can be traded independently in the market. As shown in Figure 1, the small annular portion 6 is fitted between the counterbore portion 2b of the inner ring 2 and the shoulder portion 3d of the outer ring 3. The large annular portion 7 is fitted between the counterbore portion 3b of the outer ring 3 and the shoulder portion 2d of the inner ring 2. As shown in Figure 3, the large annular portion 7 is located radially outward of the small annular portion 6. The pillar portions 8 connect the small annular portion 6 and the large annular portion 7 and are provided at multiple points in the circumferential direction.

[0020] The small annular portion 6, the large annular portion 7, and the column portion 8 form a pocket Pt that holds a number of balls 4. The small annular portion 6, the large annular portion 7, and the column portion 8 are integrally formed. The term "integral" means that the small annular portion 6, the large annular portion 7, and the column portion 8 are not formed by combining a number of elements, but are molded from a single material by, for example, injection molding, as part or the whole of a single object.

[0021] The column portion 8 has an inner diameter side column portion 8a and an outer diameter side column portion 8b. The inner diameter side column portion 8a extends between the small annular portion 6 and the large annular portion 7, generally along the axial direction, from the small annular portion 6 toward the large annular portion 7. The outer diameter side column portion 8b extends between the small annular portion 6 and the large annular portion 7, generally along the axial direction, from the large annular portion 7 toward the small annular portion 6. The inner diameter side column portion 8a has a first inclined surface 8c formed on the right side of FIG. 3, which is the large annular portion side. The first inclined surface 8c is an inclined surface that inclines radially outward as it approaches the front surface of the bearing, and reaches the large annular portion 7.

[0022] 1, the small annular portion 6 has a first inner circumferential surface 6a and a first outer circumferential surface 6b. The first inner circumferential surface 6a is the surface of the small annular portion 6 that is closest to the inner ring 2. The first outer circumferential surface 6b is the surface of the small annular portion 6 that is closest to the outer ring 3, and is located radially inward of the pitch circle diameter PCD of the balls 4.

[0023] The large annular portion 7 has a second inner peripheral surface 7a and a second outer peripheral surface 7b. The second inner peripheral surface 7a is the surface of the large annular portion 7 closest to the inner ring 2 and is located radially outward of the pitch circle diameter PCD of the balls 4. The second outer peripheral surface 7b is the surface of the large annular portion 7 closest to the outer ring 3. As shown in FIG. 3, the first inclined surface 8c connects to the second inner peripheral surface 7a of the large annular portion 7 from an end P1 on the large annular portion side, which is flush with the first inner peripheral surface 6a. The outer diameter side column portion 8b has a second inclined surface 8d that is an inclined surface that inclines radially outward toward the front surface of the bearing and reaches the large annular portion 7.

[0024] <Parameters and Effects> For the angular contact ball bearing mentioned above, the results of a step-up test described later have shown that when the radial thickness of small annular portion 6 is T1, the radial thickness of large annular portion 7 is T2, and the diameter of balls 4 is Da, and the following formulas (1), (2), and (3) are all satisfied, the strength of cage 5 is ensured to a certain level even under high load capacity and high speed rotation, and there is no interference between the raceways and cage 5. Note that high load capacity and high speed rotation are determined appropriately depending on the application and operating conditions of the angular contact ball bearing. 0.170≦T1 / Da≦0.280…Formula (1) 0.170≦T2 / Da≦0.280…Formula (2) 0.90≦T1 / T2≦1.10…Formula (3)

[0025] For a cage having a so-called asymmetric cross section, T1 / Da, which is the radial thickness T1 of the small annular portion 6 divided by the diameter Da of the ball 4, and T2 / Da, which is the radial thickness T2 of the large annular portion 7 divided by the diameter Da of the ball 4, are set within the ranges of the above formulas (1) and (2). This ensures that the strength of the cage 5 is at least a certain level, and prevents the cage 5 from interfering with at least one of the inner and outer raceways. Furthermore, by controlling T1 / T2, obtained by dividing the radial thickness T1 of the small annular portion 6 by the radial thickness T2 of the large annular portion 7, within the range of formula (3) above, it is possible to maintain a balance in the thicknesses of the small annular portion 6 and the large annular portion 7 and suppress whirling of the retainer 5 during high-speed rotation. Therefore, even under high load capacities and at high speeds, the strength of the retainer 5 can be ensured to a certain level, resulting in an angular contact ball bearing with a longer life.

[0026] As shown in FIG. 1, in the angular ball bearing 1, when the contact angle α is 30 degrees or more and 45 degrees or less, the outer diameter of the outer ring 3 is D, and the inner diameter of the inner ring 2 is d, it is preferable that the following relational expression (4) holds. 0.62≦2Da / (Dd)≦0.80 …Equation (4) When the contact angle α is set to 30 degrees or more and 45 degrees or less, a higher load capacity can be achieved than with angular contact ball bearings with contact angles α of, for example, 15 degrees or 25 degrees. Also, from the above relational expression (4), balls 4 are used that have a relatively large diameter Da relative to the outside diameter D of the outer ring 2 and the inside diameter d of the inner ring 2. This allows the angular contact ball bearing 1 to have an even higher load capacity.

[0027] In the angular contact ball bearing 1, when the axial center axis of the entire angular contact ball bearing and the axial center axis A5 (Figure 3) of the retainer 5 overlap, the radial clearance between the opposing surface of the pocket Pt of the retainer 5 facing the balls 4 and the ball surface is A, and the pitch circle diameter of the balls 4 is PCD, it is preferable that the following relationship equations (5) and (6) hold. A / Da≦0.020…Formula (5) 2A / PCD≦0.010…Formula (6)

[0028] In this case, by appropriately adjusting the clearance A relative to the diameter Da and pitch circle diameter PCD of the balls 4, the amount of movement of the retainer 5 during operation of the angular contact ball bearing 1 becomes appropriate. This ensures the stability of the retainer 5 during operation of the bearing. When the clearance A is controlled as described above, the occurrence of a speed difference between the inner ring 2 / outer ring 3 and the balls 4 is suppressed. This is because the rotation of the balls 4 is not suppressed and the rotation speed of the balls 4 does not decrease. As a result, the occurrence of abnormal noise, vibration, and temperature rise that occurs between the inner ring 2 / outer ring 3 and the balls 4 due to the speed difference between the inner ring 2 / outer ring 3 and the balls 4 can be stably suppressed.

[0029] As shown in FIG. 4, in the angular contact ball bearing, when the circumferential width of the column portion is T3 and the pitch circle diameter of the balls 4 is PCD, it is preferable that the following relational expression (7) holds. 0.01≦T3 / PCD≦0.05…Formula (7) If T3 / PCD, obtained by dividing the column width T3 by the pitch circle diameter PCD, is less than 0.01, the strength of the cage 5 may be insufficient. If T3 / PCD is more than 0.05, the load capacity may be reduced. By keeping T3 / PCD within the above range, the strength of the cage 5 is ensured, and an angular contact ball bearing can be obtained without reducing the ball diameter or the number of balls.

[0030] <Step-up test> Regarding the permissible rotational speed, a step-up test was carried out for the example and the comparative example. 1. Test bearing Equivalent to model number 7308B (inner diameter φ40mm x outer diameter φ90mm x width 23mm, contact angle 40°) In both the comparative example and the example, 7308B was used as a back-to-back duplex angular contact ball bearing. Equivalent to model number 7210B (inner diameter φ50mm x outer diameter φ90mm x width 20mm, contact angle 40°) In both the comparative example and the example, a duplex angular contact ball bearing was used in which 7210B was mated back to back.

[0031] 2. Test conditions Preload: Back-to-back combination, constant preload 2kN Lubrication: Circulating oil, grease Rotation speed: 2000~10000min -1 (1000min -1 (Step up every time) Test stop: Until the temperature of the outer ring (fixed ring) reaches 70℃ Operating time: Circulating oil supply...20 min each, Grease...60 min each 3. Test Results In the comparative example and the embodiment, operation was possible without abnormal noise, temperature rise, or abnormal heat generation. Regarding the model number 7308B equivalent, the embodiment example had less heat generation than the comparative example, and achieved a 10% improvement in the allowable rotation speed compared to the comparative example.

[0032] The relationship between the ratios of T1 / Da and T2 / Da and the strength of the cage and interference with the raceways is shown in Table 1 below. [Table 1]

[0033] In Table 1, in the column for insufficient cage strength, ◯ indicates that the cage strength is sufficient, △ indicates that there is a problem with the cage strength, and × indicates that the cage strength is insufficient.In the column for interference with raceways, ◯ indicates that the cage and raceways do not interfere, △ indicates that there is a risk of interference between the cage and raceways, and × indicates that the cage and raceways interfere. According to Table 1, if T1 / Da or T2 / Da is less than 0.170, there is concern about insufficient cage strength. If T1 / Da or T2 / Da is more than 0.280, there is concern about interference between the cage and the raceway.

[0034] The relationship between T3 / PCD and the reduction in cage strength and load capacity is shown in Table 2 below. [Table 2]

[0035] In Table 2, in the column for insufficient cage strength, ◯ indicates that the cage strength is ensured, △ indicates that there is a problem with the cage strength, and × indicates that the cage strength is insufficient.In the column for reduction in load capacity, ◯ indicates that the cage has a sufficient load capacity, △ indicates that it is possible to implement although there is a concern that the load capacity may be reduced, and × indicates that the load capacity will be reduced. According to Table 2, if T3 / PCD is less than 0.01, there is concern that the cage may have insufficient strength. If T3 / PCD is more than 0.05, there is concern that the ball diameter or the number of balls may need to be reduced, resulting in a decrease in load capacity.

[0036] <Other embodiments> The angular contact ball bearing 1 in FIG. 1 described above can be used not only in back-to-back arrangement, but also in face-to-face arrangement and parallel arrangement, and can also be used in a single row. The cage 5 may be formed by a combination of injection molding and machining, and can also be formed by using a 3D printer or the like.

[0037] Although the embodiment for carrying out the present invention has been described above, the embodiment disclosed herein is illustrative in all respects and is not restrictive. The scope of the present invention is indicated by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0038] 1...angular contact ball bearing, 2...inner ring, 2b...counterbore portion, 2d...shoulder portion, 3...outer ring, 3b...counterbore portion, 3d...shoulder portion, 4...ball, 5...retainer, 6...small annular portion, 7...large annular portion, 8...column portion, Pt...pocket, α...contact angle, PCD...pitch circle diameter

Claims

1. An angular contact ball bearing comprising an inner ring and an outer ring each having a counterbore portion, a plurality of balls interposed between the inner ring and the outer ring, and a cage that holds the balls, the cage has a small annular portion located radially between a counterbore portion of the inner ring and a shoulder portion of the outer ring, a large annular portion located radially between the counterbore portion of the outer ring and a shoulder portion of the inner ring, and pillar portions connecting the small annular portion and the large annular portion and provided at a plurality of positions in the circumferential direction, the small annular portion, the large annular portion and the pillar portions forming a pocket for holding the plurality of balls, When the radial thickness of the small annular portion is T1, the radial thickness of the large annular portion is T2, and the diameter of the ball is Da, 0.170≦T1 / Da≦0.280 0.170≦T2 / Da≦0.280 An angular contact ball bearing that satisfies 0.90≦T1 / T2≦1.

10.

2. 2. The angular ball bearing according to claim 1, wherein the contact angle is 30 degrees or more and 45 degrees or less, and the following relationship holds when the outer diameter of the outer ring is D and the inner diameter of the inner ring is d. 0.62≦2Da / (D-d)≦0.80

3. 3. An angular contact ball bearing as described in claim 1 or claim 2, in which the following relationship holds when the radial clearance between the ball-facing surface of the pocket of the retainer and the ball surface when the axial center axis of the entire angular contact ball bearing and the axial center axis of the retainer are aligned is A and the pitch circle diameter of the ball is PCD. A / Da≦0.020 2A / PCD≦0.010

4. 2. The angular ball bearing according to claim 1, wherein the following relationship holds when the circumferential width of the column portion is T3 and the pitch circle diameter of the ball is PCD. 0.01≦T3 / PCD≦0.05

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