Angular contact ball bearing

Abstract

An angular contact ball bearing (1) includes an inner ring (2) and an outer ring (3), a plurality of balls (4), and a retainer (5). The retainer (5) has: a small annular portion (6) located radially between the countersunk portion (2b) of the inner ring (2) and the shoulder portion (3d) of the outer ring (3); a large annular portion (7) located radially between the countersunk portion (3b) of the outer ring (3) and the shoulder portion (2d) of the inner ring (2); and a column portion (8) connecting the small annular portion (6) and the large annular portion (7) and disposed in a plurality of places along the circumference, wherein the small annular portion (6), the large annular portion (7) and the column portion (8) form a pocket (Pt) for retaining the plurality of balls (4). Let the radial thickness of the small annular part (6) be (T1), the radial thickness of the large annular part (7) be (T2), and the diameter of the ball (4) be (Da). At this time, the following conditions are met: 0.170≤T1 / Da≤0.280; 0.170≤T2 / Da≤0.280; 0.90≤T1 / T2≤0.10.

Description

[0001] Related applications

[0002] This application claims priority to Japanese Patent Application No. 2023-200059, filed on November 27, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates, for example, to an angular contact ball bearing for use in compressors, pumps, injection molding machines, etc. Background Technology

[0004] Patent document 1 discloses an angular contact ball bearing that does not produce abnormal noise, vibration, or temperature rise and meets the relationships specified for the internal design of the bearing.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2022-24610 Summary of the Invention

[0008] The technical problem that the invention aims to solve

[0009] Angular contact ball bearings used in compressors, pumps, injection molding machines, etc., need to have high load capacity and be able to rotate at high speeds.

[0010] In traditional angular contact ball bearings, to avoid abnormal noise, vibration, and temperature rise, such as Figure 5 As shown, the pocket clearance A of the cage 50 is controlled. On the other hand, when angular contact ball bearings are used under conditions of high load capacity and high speed rotation, the cage will also bear the load, so the cage needs to have a certain degree of strength.

[0011] The purpose of this invention is to provide an angular contact ball bearing that can ensure the strength of the cage remains above a certain level even under high load capacity and high speed rotation conditions, thereby extending its service life.

[0012] Technical solutions for solving the problem

[0013] The angular contact ball bearing of the present invention includes an inner ring and an outer ring each having a countersunk portion, a plurality of balls sandwiched between the inner ring and the outer ring, and a retainer for holding the balls.

[0014] The retainer has: a small annular portion located radially between the countersunk portion of the inner ring and the shoulder of the outer ring; a large annular portion located radially between the countersunk portion of the outer ring and the shoulder of the inner ring; and post portions connecting the small annular portion and the large annular portion and disposed at multiple locations circumferentially; these small annular portions, large annular portions and post portions form a pocket for retaining the plurality of balls.

[0015] Wherein, let the radial thickness of the small annular portion be T1, the radial thickness of the large annular portion be T2, and the diameter of the ball be Da, then the following conditions are met: 0.170≤T1 / Da≤0.280 0.170≤T2 / Da≤0.280 0.90≤T1 / T2≤1.10.

[0016] T1 refers to the radial thickness of the outer axial portion of the small annular part;

[0017] T2 refers to the radial thickness of the outer axial portion of the large annular part;

[0018] The shoulder of the outer ring is the inner circumference of the back side of the outer ring;

[0019] The shoulder of the inner ring is the outer periphery of the back side of the inner ring.

[0020] According to this structure, for a so-called asymmetrical cross-section retainer, the ratio T1 / Da (obtained by dividing the radial thickness T1 of the small annular portion by the diameter Da of the ball) and the ratio T2 / Da (obtained by dividing the radial thickness T2 of the large annular portion by the diameter Da of the ball) are set within the aforementioned range. This ensures that the retainer's strength is above a certain level and prevents interference between the retainer and at least one of the raceway rings, the inner or outer ring.

[0021] Furthermore, by controlling the ratio T1 / T2 (the radial thickness T1 of the small annular portion divided by the radial thickness T2 of the large annular portion) within the aforementioned range, the thickness balance between the small and large annular portions can be maintained, suppressing cage wobbling during high-speed rotation. Therefore, even under conditions of high load capacity and high-speed rotation, the strength of the cage can be ensured to remain above a certain level, thereby achieving a longer service life for the angular contact ball bearing.

[0022] When the contact angle is between 30 and 45 degrees, and the outer diameter of the outer ring is D and the inner diameter of the inner ring is d, the following relationship holds: 0.62≤2Da / (D−d)≤0.80.

[0023] When the contact angle is set to 30 degrees or more and 45 degrees or less, a higher load capacity can be achieved compared to angular contact ball bearings with contact angles of, for example, 15 degrees or 25 degrees. Furthermore, according to the aforementioned formula, balls with a larger diameter Da relative to the outer ring outer diameter D and the inner ring inner diameter d are used. This further increases the load capacity of the angular contact ball bearing.

[0024] Let A be the radial clearance between the cage pocket and the opposing surface of the ball bearing and the ball surface when the axial center axis of the angular contact ball bearing as the whole coincides with the axial center axis of the cage, and let PCD be the pitch circle diameter of the ball. Then the following relationship holds: A / Da≤0.020 2A / PCD≤0.010.

[0025] In this case, by appropriately adjusting the clearance A relative to the ball diameter Da and the pitch circle diameter PCD, the movement of the cage during the operation of the angular contact ball bearing is moderate. This ensures the stability of the cage during bearing operation. When the clearance A is controlled as described above, the speed difference between the inner ring, outer ring, and balls is suppressed. This is because the rotation of the balls is not suppressed, and the rotational speed of the balls is not reduced. Therefore, it is possible to stably suppress abnormal noises, vibrations, and temperature rises caused by the speed difference between the inner ring, outer ring, and balls.

[0026] Let the circumferential width of the column (i.e., the column width) be T3, and the pitch circle diameter of the ball be PCD. Then the following relationship holds: 0.01≤T3 / PCD≤0.05.

[0027] When the ratio T3 / PCD (the column width T3 divided by the pitch circle diameter PCD) is less than 0.01, the cage strength may be insufficient. When T3 / PCD is greater than 0.05, the load capacity may decrease. By setting T3 / PCD within the aforementioned range, the cage strength is ensured, and angular contact ball bearings can be obtained without reducing the ball diameter or the number of balls.

[0028] Any combination of at least two structures disclosed in the claims and / or description and / or drawings is part of this invention. In particular, any combination of two or more claims in the claims is part of this invention. Attached Figure Description

[0029] The invention will be more clearly understood through the following description of preferred embodiments with reference to the accompanying drawings. However, the embodiments and drawings are for illustration and description only and are not intended to limit the scope of the invention. The scope of the invention is defined by the claims. In the drawings, the same reference numerals in multiple figures denote the same or equivalent parts.

[0030] Figure 1 This is a longitudinal sectional view of an angular contact ball bearing according to a first embodiment of the present invention.

[0031] Figure 2 This is a perspective view of the retainer of the angular contact ball bearing.

[0032] Figure 3 This is an enlarged cross-sectional view of the main part of the retainer.

[0033] Figure 4 This is a sectional view obtained by cutting the retainer along a plane perpendicular to the axis and observing it locally.

[0034] Figure 5 This is a partially enlarged cross-sectional view of the retainer in an existing angular contact ball bearing. Detailed Implementation

[0035] [First Implementation]

[0036] The following combination Figures 1 to 4 This invention describes an angular contact ball bearing according to an embodiment of the present invention. This angular contact ball bearing is used, for example, in compressors, pumps, injection molding machines, etc. However, the angular contact ball bearing is not limited to these applications and can be used in various industrial machinery, etc. In this specification, the angular contact ball bearing is sometimes simply referred to as a "bearing".

[0037] <Integral Structure of Angular Contact Ball Bearing>

[0038] like Figure 1 As shown, the angular contact ball bearing 1 includes an inner ring 2 and an outer ring 3 as raceway rings, a plurality of balls 4 sandwiched between the raceway surface 2a of the inner ring 2 and the raceway surface 3a of the outer ring 3, and a retainer 5 having pockets Pt formed to hold these balls 4. A contact angle α is formed on the raceway surfaces 2a and 3a of the inner ring 2 and the outer ring 3.

[0039] The inner ring 2 and outer ring 3 are made of, for example, high-carbon chromium bearing steel such as SUJ2 or martensitic stainless steel. The ball 4 is made of, for example, steel balls or ceramics. The retainer 5 is formed into a ring shape, for example, nylon, PPS, PEEK, or phenolic resin reinforced with glass fiber or carbon fiber.

[0040] In this specification, "axial" refers to the direction along the bearing centerline AX of the angular contact ball bearing 1. "Radial" refers to the direction orthogonal to the straight line constituting the "axial" direction.

[0041] The front side of the outer ring 3 is connected to the raceway surface 3a via the countersunk portion 3b (described later). The front side of the outer ring 3 represents the side that does not bear axial load. The back side 3c of the outer ring 3 represents the side that bears axial load. The shoulder 3d, which is the inner circumferential surface of the back side of the outer ring 3, is located radially inside the countersunk portion 3b of the outer ring 3. The front side of the inner ring 2 is connected to the raceway surface 2a via the countersunk portion 2b (described later). The front side of the inner ring 2 represents the side that does not bear axial load. The back side 2c of the inner ring 2 represents the side that bears axial load. The inner circumferential surface of the back side of the inner ring 2 is referred to as the shoulder 2d. The shoulder 2d is formed between the raceway surface 2a and the back side 2c of the inner ring 2. The shoulder 2d of the inner ring 2 is located radially outside the countersunk portion 2b of the inner ring 2.

[0042] The shoulder 3d of the outer ring 3 is formed as a cylindrical surface parallel to the axial direction. The countersunk portion 3b of the outer ring 3 is formed as a cylindrical or conical surface, which is formed radially outward of the shoulder 3d and has a larger diameter of a specified size; it is also called the "relief groove" of the outer ring 3. The conical surface is a conical surface that gradually slopes radially inward from the front side of the outer ring towards the raceway surface 3a. The shoulder 2d of the inner ring 2 is formed as a cylindrical surface parallel to the axial direction. The countersunk portion 2b of the inner ring 2 is formed as a cylindrical or conical surface, which is formed radially inward of the shoulder 2d and has a smaller diameter of a specified size; it is also called the "relief groove" of the inner ring 2. The conical surface is a conical surface that gradually slopes radially outward from the front side of the inner ring towards the raceway surface 2a.

[0043] <About the retainer>

[0044] like Figure 2 and Figure 3 As shown, the retainer 5 has a small annular portion 6, a large annular portion 7, and a column portion 8. This retainer 5 can be independently traded on the market. Figure 1 As shown, the small annular portion 6 is housed between the countersunk portion 2b of the inner ring 2 and the shoulder 3d of the outer ring 3. The large annular portion 7 is housed between the countersunk portion 3b of the outer ring 3 and the shoulder 2d of the inner ring 2. Figure 3 As shown, the large annular portion 7 is located radially outside the small annular portion 6. The column portion 8 connects the small annular portion 6 and the large annular portion 7, and is provided at multiple locations along the circumference.

[0045] The pocket Pt for holding multiple balls 4 is formed by a small annular portion 6, a large annular portion 7, and a column portion 8. The small annular portion 6, the large annular portion 7, and the column portion 8 are integrally formed. The term "integrated" means that the small annular portion 6, the large annular portion 7, and the column portion 8 are not composed of multiple components, but are formed from a single material, for example, by injection molding, into part or whole of a single product.

[0046] 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 is located between the small annular portion 6 and the large annular portion 7, extending generally axially from the small annular portion 6 towards the large annular portion 7. The outer diameter side column portion 8b is located between the small annular portion 6 and the large annular portion 7, extending generally axially from the large annular portion 7 towards the small annular portion 6. The inner diameter side column portion 8a is located on its large annular portion side... Figure 3 A first inclined surface 8c is formed on the right side. The first inclined surface 8c is an inclined surface that gradually slopes radially outward toward the front side of the bearing and reaches the large annular portion 7.

[0047] like Figure 1 As shown, 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 closest to the inner ring 2. The first outer circumferential surface 6b is the surface of the small annular portion 6 closest to the outer ring 3, located radially inside the pitch circle diameter PCD of the ball 4.

[0048] The large annular portion 7 has a second inner circumferential surface 7a and a second outer circumferential surface 7b. The second inner circumferential surface 7a is the surface of the large annular portion 7 closest to the inner ring 2, located radially outward of the pitch circle diameter PCD of the ball 4. The second outer circumferential surface 7b is the surface of the large annular portion 7 closest to the outer ring 3. Figure 3 As shown, the first inclined surface 8c connects from the end P1 of the large annular portion, which is on the same side as the first inner circumferential surface 6a, to the second inner circumferential surface 7a of the large annular portion 7. The outer diameter side column portion 8b has a second inclined surface 8d, which is an inclined surface that gradually slopes radially outward toward the bearing front side and reaches the large annular portion 7.

[0049] <Parameters and Effects>

[0050] For the aforementioned angular contact ball bearing, according to the results of the stepped speed increase test described later, when the radial thickness of the small annular portion 6 is set to T1, the radial thickness of the large annular portion 7 is set to T2, and the diameter of the ball 4 is set to Da, if all of the following equations (1), (2), and (3) are satisfied, then even under high load capacity and high speed rotation conditions, the strength of the cage 5 can be ensured to be above a certain level, and the raceway ring and the cage 5 will not interfere. In addition, the high load capacity and high speed rotation are appropriately set according to the application and operating conditions of the angular contact ball bearing. 0.170≤T1 / Da≤0.280 … Equation (1) 0.170≤T2 / Da≤0.280 … Equation (2) 0.90≤T1 / T2≤1.10 … Equation (3)

[0051] For a retainer with a so-called asymmetrical cross-section, the radial thickness T1 of the small annular portion 6 divided by the diameter Da of the ball 4, resulting in T1 / Da, and the radial thickness T2 of the large annular portion 7 divided by the diameter Da of the ball 4, resulting in T2 / Da, are set within the range of the above equations (1) and (2). This ensures that the strength of the retainer 5 is above a certain level and prevents interference between the retainer 5 and at least one of the raceway rings, the inner ring and the outer ring.

[0052] Furthermore, by controlling the ratio 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 the above formula (3), the thickness balance between the small annular portion 6 and the large annular portion 7 can be maintained, suppressing the oscillation of the retainer 5 during high-speed rotation. Therefore, even under conditions of high load capacity and high-speed rotation, the strength of the retainer 5 can be ensured to be above a certain level, thereby achieving a longer service life for the angular contact ball bearing.

[0053] like Figure 1 As shown, in the angular contact ball bearing 1, the contact angle α is more than 30 degrees and less than 45 degrees. Let the outer diameter of the outer ring 3 be D and the inner diameter of the inner ring 2 be d. In this case, the following relationship (4) is preferably true. 0.62≤2Da / (D−d)≤0.80 … Equation (4)

[0054] When the contact angle α is set to 30 degrees or more and 45 degrees or less, a higher load capacity can be achieved compared to angular contact ball bearings with contact angles α of, for example, 15 degrees or 25 degrees. Furthermore, according to the aforementioned formula (4), balls 4 with a larger diameter Da relative to the outer diameter D of the outer ring 3 and the inner diameter d of the inner ring 2 are used. This further increases the load capacity of the angular contact ball bearing 1.

[0055] In the angular contact ball bearing 1, the axial central axis of the entire angular contact ball bearing is aligned with the axial central axis A5 of the retainer 5. Figure 3 In the overlapping state, the radial clearance between the pocket Pt of the retainer 5 and the opposite face of the ball 4 and the ball surface is A, and the pitch circle diameter of the ball 4 is PCD. At this time, the following relationships (5) and (6) are preferably established. A / Da≤0.020 … Equation (5) 2A / PCD≤0.010 … Equation (6)

[0056] In this case, by appropriately adjusting the clearance A relative to the diameter Da and pitch circle diameter PCD of the ball 4, the movement of the retainer 5 during operation of the angular contact ball bearing 1 is moderate. This ensures the stability of the retainer 5 during bearing operation. When clearance A is controlled as described above, the speed difference between the inner ring 2, outer ring 3, and ball 4 is suppressed. This is because the rotation of ball 4 is not suppressed, and the rotational speed of ball 4 is not reduced. Therefore, it is possible to stably suppress abnormal noise, vibration, and temperature rise caused by the speed difference between the inner ring 2, outer ring 3, and ball 4.

[0057] like Figure 4 As shown, in the angular contact ball bearing, if the circumferential width of the column portion, i.e. the column width, is T3, and the pitch circle diameter of the ball 4 is PCD, then the following relationship (7) is preferably true. 0.01≤T3 / PCD≤0.05 … Equation (7)

[0058] When the ratio 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. When T3 / PCD is greater than 0.05, the load capacity may decrease. By setting T3 / PCD within the aforementioned range, the strength of the cage 5 is ensured, and angular contact ball bearings can be obtained without reducing the ball diameter or the number of balls.

[0059] <Step-by-step acceleration test>

[0060] For the permissible speed, a stepped speed-up test was performed in the examples and comparative examples.

[0061] 1. Test bearing

[0062] • Equivalent to model 7308B (inner diameter φ40mm × outer diameter φ90mm × width 23mm, contact angle 40°)

[0063] Both the comparative example and the embodiment use a combination angular contact ball bearing with 7308B back-to-back assembly.

[0064] • Equivalent to model 7210B (inner diameter φ50mm × outer diameter φ90mm × width 20mm, contact angle 40°)

[0065] Both the comparative example and the embodiment use a combination angular contact ball bearing in which 7210B is assembled back to back.

[0066] 2. Test conditions

[0067] Preloading: Back-to-back assembly, constant pressure preloading 2kN

[0068] Lubrication: Circulating oil supply, grease

[0069] Rotation speed: 2000~10000 min -1 (in 1000min) -1 (Increase speed by step size)

[0070] The test is stopped when the temperature of the outer ring, which serves as the fixing ring, reaches 70°C.

[0071] Operating time: 20 minutes for oil circulation and 60 minutes for grease circulation.

[0072] 3. Experimental Results

[0073] In both the comparative and embodiment examples, the equipment operated without any abnormal noise, temperature rise, or heat generation.

[0074] Regarding the bearing equivalent to model 7308B, compared with the comparative example, the heat generation of the embodiment is suppressed, and the permissible speed is increased by 10% relative to the comparative example.

[0075] The relationship between the ratios of T1 / Da and T2 / Da and the strength of the retainer and its interference with the raceway ring is shown in Table 1 below.

[0076] [Table 1]

[0077] Table 1. Relationship between the ratios of T1 / Da and T2 / Da and the strength of the retainer and its interference with the raceway ring.

[0078]

[0079] In Table 1, under the column for "Insufficient Cage Strength," ○ indicates that the cage strength is guaranteed, △ indicates that there is a problem with the cage strength, and × indicates that the cage strength is insufficient. Under the column for "Interference with Raceway Ring," ○ indicates that there is no interference between the cage and the raceway ring, △ indicates that there may be interference between the cage and the raceway ring, and × indicates that there is interference between the cage and the raceway ring.

[0080] As shown in Table 1, when T1 / Da or T2 / Da is less than 0.170, the insufficient strength of the retainer is a concern. When T1 / Da or T2 / Da is greater than 0.280, there is a potential risk of interference between the retainer and the raceway ring.

[0081] The relationship between T3 / PCD and the strength and load capacity reduction of the retainer is shown in Table 2 below.

[0082] [Table 2]

[0083] Table 2. Relationship between T3 / PCT and reduction in retainer strength and load capacity

[0084]

[0085] In Table 2, under the "Insufficient Cage Strength" column, ○ indicates that the cage strength is guaranteed, △ indicates that there is a problem with the cage strength, and × indicates that the cage strength is insufficient. Under the "Reduced Load Capacity" column, ○ indicates that the necessary and sufficient load capacity is available, △ indicates that although there is a potential for reduced load capacity, it is feasible, and × indicates reduced load capacity.

[0086] As shown in Table 2, when T3 / PCD is less than 0.01, there is a risk of insufficient strength in the retainer. When T3 / PCD is greater than 0.05, it is necessary to reduce the diameter of the balls or the number of balls, which may result in a decrease in load capacity.

[0087] <Regarding other implementation methods>

[0088] The above explanation Figure 1 The angular contact ball bearing 1 can be used not only back-to-back, but also face-to-face, side-by-side, or in a single row.

[0089] The retainer 5 can be formed by combining injection molding and machining, or by using a 3D printer.

[0090] As mentioned above, while referring to the appendix Figure 1 While the preferred embodiments have been described, various additions, modifications, and deletions can be made without departing from the spirit of the invention. Therefore, these are also included within the scope of the invention.

[0091] Symbol Explanation

[0092] 1… Angular contact ball bearings

[0093] 2… Inner circle

[0094] 2b… ​​Countersunk hole section

[0095] 2D… Shoulder

[0096] 3… Outer ring

[0097] 3b… Countersunk hole section

[0098] 3D… Shoulder

[0099] 4… Ball bearings

[0100] 5… Holder

[0101] 6… Small ring-shaped part

[0102] 7… Large circumferential section

[0103] 8… Column

[0104] Pt… pocket

[0105] A… Contact angle

[0106] PCD… Pitch circle diameter.

Claims

1. An angular contact ball bearing, comprising an inner ring and an outer ring each having a countersunk portion, a plurality of balls disposed between the inner ring and the outer ring, and a retainer for holding the balls; The retainer has: a small annular portion located radially between the countersunk portion of the inner ring and the shoulder of the outer ring; a large annular portion located radially between the countersunk portion of the outer ring and the shoulder of the inner ring; and post portions connecting the small annular portion and the large annular portion and disposed at multiple locations circumferentially; these small annular portions, large annular portions and post portions form a pocket for retaining the plurality of balls. in, Let the radial thickness of the small annular portion be T1, the radial thickness of the large annular portion be T2, and the diameter of the ball be Da. Then the following conditions are met: 0.170≤T1 / Da≤0.280 0.170≤T2 / Da≤0.280 0.90≤T1 / T2≤1.

10.

2. The angular contact ball bearing according to claim 1, characterized in that, When the contact angle is between 30 degrees and 45 degrees, and the outer diameter of the outer ring is D and the inner diameter of the inner ring is d, the following relationship holds: 0.62≤2Da / (D−d)≤0.

80.

3. The angular contact ball bearing according to claim 1 or 2, characterized in that, Let A be the radial clearance between the cage pocket and the opposing surface of the ball bearing, and PCD be the pitch circle diameter of the ball bearing, when the axial center axis of the angular contact ball bearing as the axial center axis of the cage coincides with that of the cage. In this case, the following relationship holds: A / Da≤0.020 2A / PCD≤0.

010.

4. The angular contact ball bearing according to claim 1, characterized in that, Let the circumferential width of the column (i.e., the column width) be T3, and the pitch circle diameter of the ball be PCD. Then the following relationship holds: 0.01≤T3 / PCD≤0.05.

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