Inner ring separation type angular contact ball bearing

Abstract

The present invention relates to an inner ring separation type angular contact ball bearing, which smoothly inserts an inner ring into an outer ring assembly, and is not easily damaged to the surface of a ball, an inner and outer ring raceway groove. It is configured that a point where a center line passing through a contact point and a center of a ball intersects with a surface of the ball is taken as a crossing point, a rotation angle around the center of the ball in a direction where the ball falls from the crossing point is taken as positive, and a reverse direction is taken as negative, the contact point is a point between the ball and an outer ring shoulder portion when the ball of the outer ring assembly falls to a radial inner side due to its own weight, an abutting point where the ball and an inner ring counterbore portion first abut when the inner ring is inserted downward is located on a positive side than the crossing point, a radial gap between an outer diameter of a circumscribed circle of the ball and a groove bottom of the outer ring raceway groove, that is, a size C of a ball circumscribed side gap, and a difference between an inner diameter of an inscribed circle of the ball and an outer diameter of the inner ring counterbore portion when the inner ring is inserted downward from the inner ring counterbore portion side, that is, a size D of a ball inscribed side overlap, satisfy a relationship of 1.00 < C / D ≤ 2.50.

Description

Technical Field

[0001] The present invention relates to an inner ring separable angular contact ball bearing, which is configured to allow the inner ring to be smoothly inserted when the inner ring is inserted into an assembly that integrally holds the outer ring, the retainer, and the rolling elements. Background Technology

[0002] Previously, bearings used in automotive automatic transmissions were subjected to both high radial and axial loads, thus tapered roller bearings, which employed a tapered profile, were mostly used. However, in recent years, due to the demand for fuel efficiency in automobiles, angular contact ball bearings have been increasingly used in transmission bearings. Angular contact ball bearings can withstand both radial and axial loads and offer lower torque compared to tapered roller bearings.

[0003] In transmissions using angular contact ball bearings, separable angular contact ball bearings are typically employed to ensure ease of assembly and disassembly. Separable angular contact ball bearings are configured such that the balls will not detach from the retainer pockets when the inner or outer ring is separated.

[0004] As a separable angular contact ball bearing, for example, there is an inner ring separable angular contact ball bearing as described in Patent Document 1. The inner ring separable angular contact ball bearing of Patent Document 1 includes: an outer ring; an inner ring coaxially disposed radially inside the outer ring; a plurality of balls spaced apart circumferentially between the outer ring and the inner ring; and a retainer for holding the plurality of balls.

[0005] The outer ring has an outer ring raceway groove for ball rolling contact, an outer ring countersunk hole adjacent to one axial side of the outer ring raceway groove, and an outer ring shoulder adjacent to the other axial side of the outer ring raceway groove. Similarly, the inner ring has an inner ring raceway groove for ball rolling contact, an inner ring countersunk hole adjacent to one axial side of the inner ring raceway groove, and an inner ring shoulder adjacent to the other axial side of the inner ring raceway groove. The outer ring countersunk hole is a portion of the outer ring raceway groove that has been partially or completely removed, and the inner ring countersunk hole is a portion of the inner ring raceway groove shoulder that has been partially or completely removed.

[0006] Patent Document 1: Japanese Patent Application Publication No. 2008-95929

[0007] In the inner ring separable angular contact ball bearing described in Patent Document 1, for example... Figure 13As shown, when the inner ring 54 is inserted into the retainer (hereinafter referred to as the outer ring assembly) which integrally holds the outer ring 51, retainer 52 and ball 53 embedded in the housing hole 50, the ball 53, which falls radially inward due to its own weight, is further introduced downward by the downwardly inserted inner ring 54, causing the outer ring 51, ball 53 and retainer 52 to separate, or the ball 53 gets stuck between the outer ring 51 and the inner ring 54 as the inner ring 54 is inserted. There is a concern that the inner ring 54 cannot be inserted smoothly and that the surface of the ball 53 and the inner and outer ring track grooves may be damaged. Summary of the Invention

[0008] The problem to be solved by the present invention is to provide an inner ring separable angular contact ball bearing that allows the inner ring to be smoothly inserted into the outer ring assembly without easily damaging the surface of the balls or the inner and outer ring raceways.

[0009] To address the aforementioned issues, this invention provides an inner ring separation type angular contact ball bearing with the following structure.

[0010] An inner ring separable angular contact ball bearing, characterized in that it comprises:

[0011] Outer ring;

[0012] The inner ring is coaxially disposed radially inside the outer ring described above;

[0013] Multiple balls are spaced apart circumferentially between the outer ring and the inner ring; and

[0014] The retainer holds the aforementioned multiple balls.

[0015] The inner circumference of the outer ring is provided with an outer ring track groove for the rolling contact of the balls, an outer ring shoulder adjacent to one side of the axial direction of the outer ring track groove, and an outer ring countersunk hole adjacent to the other side of the axial direction of the outer ring track groove and having an inner diameter larger than that of the outer ring shoulder.

[0016] On the outer periphery of the aforementioned inner ring, there is an inner ring track groove for the aforementioned balls to roll into contact, an inner ring countersunk portion adjacent to one side of the axial direction of the aforementioned inner ring track groove, and an inner ring shoulder portion adjacent to the other side of the axial direction of the aforementioned inner ring track groove and having an outer diameter larger than the aforementioned inner ring countersunk portion.

[0017] When the inner ring is separated, the balls are supported so that they do not fall out radially inward from the pocket formed in the retainer.

[0018] With the outer ring, retainer, and ball held together as a single unit, the point where the center line passing through the contact point and the center of the ball intersects with the surface of the ball is taken as the intersection point. The rotation angle around the center of the ball in the direction from this intersection point towards the ball's fall is set to positive, and the rotation angle in the opposite direction from the intersection point is set to negative. When the inner ring is inserted downwards from the inner ring countersunk portion side, the point where the ball first abuts against the inner ring countersunk portion is located on a side more positive than the intersection point. The contact point is the point between the ball and the shoulder of the outer ring when the ball falls radially inwards due to its own weight.

[0019] Between dimensions C and D, the relationship 1.00 < C / D ≤ 2.50 holds, where dimension C is the radial clearance between the outer diameter of the ball and the bottom of the outer ring track groove when the ball falls radially inward due to its own weight, i.e., the outer side clearance of the ball, and dimension D is the difference between the inner diameter of the ball and the outer diameter of the inner ring countersunk hole when the inner ring is inserted downward from the inner ring countersunk hole side, i.e., the inner side overlap of the ball.

[0020] In this way, by making the contact point the positive side of the intersection point, when the inner ring is inserted downward into the outer ring assembly, the ball will not be drawn downward by the inner ring countersunk portion of the inner ring, thus enabling the assembly to be performed smoothly.

[0021] Furthermore, by setting the dimensional relationship between the outer ball clearance dimension C and the inner ball overlap dimension D within the aforementioned range, the ball is pushed back along the outer ring's raceway as the inner ring is inserted, thus ensuring smooth insertion. If the inner ball overlap dimension D is larger than the outer ball clearance dimension C, an interference fit will occur between the inner ring and the ball during insertion, putting pressure on the ball and potentially causing damage or breakage. Additionally, if the ratio of the outer ball clearance dimension C to the inner ball overlap dimension D is greater than 2.50, the gap between the ball and the inner / outer ring raceways increases, raising concerns about an unpredictable contact angle or the ball mounting over the inner / outer ring shoulders. Therefore, it is necessary to set the dimensional relationship between the outer ball clearance dimension C and the inner ball overlap dimension D within the aforementioned range.

[0022] Preferably, a conical surface is formed on the outer diameter side of the inner ring countersunk hole, and the axial inclination angle α of the conical surface satisfies 0°<α≤30°, and the outer diameter gradually decreases as it moves away from the inner ring track groove.

[0023] This reduces contact surface pressure compared to the case where the ball bearings directly contact the chamfered portion of the inner ring countersunk bore, thus minimizing damage to the ball bearing surface. Furthermore, by forming a tapered surface, the length of the flat portion of the intermediate shaft that needs to be ground (refer to...) Figure 4The Lc in the middle is shortened, thus reducing the manufacturing cycle. Furthermore, if the tilt angle α is greater than 30 degrees, it becomes difficult to ensure the required length of the flat portion of the inner ring width for processing (see reference). Figure 4 The Lw in the text is preferred, therefore the above range is preferred.

[0024] Preferably, a solid lubricating film is formed on the outer diameter side of the inner ring countersunk hole.

[0025] In this way, the friction between the ball and the outer diameter surface of the inner ring countersunk hole is reduced, thus allowing the inner ring to be inserted smoothly without damaging the surface of the ball.

[0026] The aforementioned inner ring split-type angular contact ball bearings are particularly preferred for use as bearings in automotive transmissions.

[0027] In the inner ring separable angular contact ball bearing of the present invention, when the balls of the outer ring assembly are inserted, the contact point between the ball and the inner ring countersunk hole is more positive than the intersection point specified on the ball surface, and the relationship 1.00 < C / D ≤ 2.50 exists between the dimension C of the clearance on the outer side of the ball and the dimension D of the overlap on the inner side of the ball. Therefore, when the inner ring is inserted downwards into the outer ring assembly, the ball is not drawn downwards by the inner ring countersunk hole, thus allowing for smooth insertion. Furthermore, by setting the dimensional relationship between the dimension C of the clearance on the outer side of the ball and the dimension D of the overlap on the inner side of the ball within the aforementioned range, the ball will not become stuck between the outer and inner rings during the insertion of the inner ring, thereby reducing the risk of damage to the ball surface and the inner and outer ring raceways. Attached Figure Description

[0028] Figure 1 This is a cross-sectional view showing one embodiment of the inner ring separable angular contact ball bearing involved in the present invention.

[0029] Figure 2 It means Figure 1 A sectional view of the main part.

[0030] Figure 3 It means Figure 2 A diagram showing the dimensional relationships of the various components.

[0031] Figure 4 yes Figure 1 The image shows a cross-sectional view of the inner ring of an inner ring-separable angular contact ball bearing.

[0032] Figure 5 It means to put one Figure 1 The diagram shows a cross-sectional view of the outer ring assembly of an inner ring separable angular contact ball bearing mounted in the housing bore.

[0033] Figure 6 It means to continue Figure 5A cross-sectional view showing the other outer ring component installed in the housing bore.

[0034] Figure 7 It means to continue Figure 6 A sectional view showing the state of a shaft with an inner ring was inserted.

[0035] Figure 8 It means to continue Figure 7 A cross-sectional view of the state of another inner circle was inserted.

[0036] Figure 9 It is a cross-sectional view showing the abutting force acting on the balls when the inner ring is inserted.

[0037] Figure 10 It means Figure 1 A cross-sectional view of the main part of a modified example of an inner ring separable angular contact ball bearing.

[0038] Figure 11 It means Figure 1 The diagram shows a cross-sectional view of a first example of the inner ring split-type angular contact ball bearing used in a car transmission.

[0039] Figure 12 It means Figure 1 The diagram shows a cross-sectional view of a second example of an inner ring split-type angular contact ball bearing used in a car transmission.

[0040] Figure 13 This is a cross-sectional view showing the main part of the insertion process of the inner ring of an inner ring separable angular contact ball bearing involved in the prior art.

[0041] Explanation of reference numerals in the attached figures

[0042] 1…Outer ring; 2…Inner ring; 3…Ball; 4…Retainer; 5…Outer ring raceway; 6…Outer ring shoulder; 7…Outer ring countersunk portion; 8…Inner ring raceway; 9…Inner ring countersunk portion; 10…Inner ring shoulder; 11…Conical surface; 15…Pocket; A…Inner ring split angular contact ball bearing; O…Center; X…Contact point; Y…Intersection point; Z…Abutment point; α…Inclination angle; β…Rotation angle. Detailed Implementation

[0043] Hereinafter, with the aid of accompanying drawings, one embodiment of the inner ring separable angular contact ball bearing A according to the present invention will be described. Figure 1 The inner ring split type angular contact ball bearing A shown has: an outer ring 1; an inner ring 2, coaxially disposed radially inside the outer ring 1; a plurality of balls 3 (steel balls), spaced apart circumferentially between the outer ring 1 and the inner ring 2; and a retainer 4, which holds the plurality of balls 3.

[0044] On the inner circumference of the outer ring 1, there is an outer ring track groove 5 for the rolling contact of the ball 3, and on one side of the outer ring track groove 5 (in the axial direction). Figure 1 The outer ring shoulder 6 adjacent to the left side (in the middle), and the other side axially opposite to the outer ring track groove 5 (in the middle). Figure 1 The outer ring countersunk portion 7 (right side) is adjacent to the outer ring. The outer ring track groove 5 is a cross-sectional arc-shaped groove extending circumferentially from the inner circumference of the outer ring 1. The outer ring 1 is formed of bearing steel. The outer ring countersunk portion 7 is the part after part or all of the shoulder of the outer ring track groove 5 has been removed. The inner diameter of the outer ring countersunk portion 7 is larger than the inner diameter of the outer ring shoulder 6.

[0045] On the outer periphery of the inner ring 2, there is an inner ring track groove 8 for the rolling contact of the balls 3, and on one side of the inner ring track groove 8 (in the axial direction). Figure 1 The inner ring consists of a countersunk hole 9 (on the left side) and an inner ring shoulder 10, which is adjacent to the inner ring track groove 8 on the other side of the axial direction. The inner ring track groove 8 is a groove with an arc-shaped cross-section extending circumferentially along the outer periphery of the inner ring 2. The inner ring 2 is made of bearing steel. The inner ring countersunk hole 9 is the portion after part or all of the shoulder of the inner ring track groove 8 has been removed. The outer diameter of the inner ring shoulder 10 is larger than the outer diameter of the inner ring countersunk hole 9.

[0046] like Figure 3 and Figure 4 As shown, the outer peripheral surface of the inner ring countersunk hole 9 becomes a conical surface 11 whose outer diameter gradually decreases as it moves away from the inner ring track groove 8. The axial inclination angle α of this conical surface 11 is greater than 0 degrees and less than 30 degrees. An axially flat intermediate shaft flat portion is formed between the inner ring track groove 8 and the conical surface 11. Figure 4 The range of Lc in the middle). In addition, a flat, wide flat portion is formed on the axial end face of the inner ring countersunk hole portion 9. Figure 4 (The range of Lw in the text).

[0047] A solid lubricating film is formed on the outer peripheral surface of the inner ring countersunk portion 9. This solid lubricating film reduces friction with the ball bearing 3 during insertion of the inner ring 2, preventing damage to the surface of the ball bearing 3 during insertion. In particular, if a solid lubricating film is formed on the conical surface 11, the insertion of the inner ring 2 can be performed more smoothly. Blackened or diamond-like carbon (DLC) can be used as this solid lubricating film. Blackened film is a porous black oxide film that imparts lubricity by retaining lubricating oil or the like within its pores. DLC is a low-friction film possessing properties intermediate between diamond and graphite, and also exhibits lubricity. Additionally, molybdenum-based or fluorine-based solid lubricating films can also be used. Furthermore, this solid lubricating film is not a necessary structure and can sometimes be omitted.

[0048] The retainer 4 has: an intermediate axial annular portion 12, which is located on one side of the axial direction relative to the ball 3 (in Figure 1The middle (left side) extends circumferentially; the annular portion 13 on the opposite side of the axial direction relative to the ball 3 (in) Figure 1 The retainer 4 extends circumferentially (from right to left) and includes multiple pillars 14 that connect the intermediate axial side annular portion 12 and the anti-intermediate axial side annular portion 13 via adjacent circumferentially spaced balls 3. The intermediate axial side annular portion 12, the anti-intermediate axial side annular portion 13, and the pillars 14 define pockets 15 for receiving the balls 3. When the inner ring 2 is separated, the balls 3 are supported by the pockets 15 to prevent them from falling radially inward. The intermediate axial side annular portion 12 and the anti-intermediate axial side annular portion 13 engage with the balls 3, thereby positioning the retainer 4. At this time, neither the intermediate axial side annular portion 12 nor the anti-intermediate axial side annular portion 13 is in contact with the outer ring 1 or the inner ring 2.

[0049] Resin is used as the material for retainer 4. The resin can be polyamides such as PA46 (polyamide 46), PA66 (polyamide 66), and PA9T (poly(1,9-nonylidene terephthalamide)), polyether ether ketone (PEEK), or polyphenylene sulfide (PPS).

[0050] like Figure 2 As shown, in the retainer (hereinafter referred to as the outer ring assembly) that integrally holds the outer ring 1, the retainer 4, and the ball 3, the ball 3 falls slightly radially inward due to its own weight. The point where the contact point X between the ball 3 and the outer ring shoulder 6 at this time intersects the center line of the ball's center O on the surface of the ball 3 is defined as the intersection point Y. Furthermore, the rotation angle β about the center O of the ball 3 in the direction from the intersection point Y towards the direction the ball 3 falls is defined as positive, and the rotation angle β in the opposite direction from the intersection point Y is defined as negative. At this time, the inner ring countersunk portion 9 of the inner ring 2, which is inserted relative to the outer ring assembly, first abuts against the ball 3 at the contact point Z. When this contact point Z is located on the side of rotation angle β that is more positive than the intersection point Y, as described later (see reference...). Figure 9 It can smoothly push the balls 3 that have fallen due to their own weight back along the outer ring track groove 5 by means of the contact force with the inner ring 2.

[0051] Furthermore, in the outer ring assembly, the relationship 1.00 < C / D ≤ 2.50 holds true between dimensions C and D. Dimension C is the radial clearance between the outer diameter Ro of the ball 3 and the bottom of the outer ring track groove 5 when the ball 3 falls radially inward due to its own weight; that is, the clearance on the outer side of the ball. Dimension D is the difference between the inner diameter Ri of the ball 3 and the outer diameter Rc of the inner ring countersunk portion 9 when the inner ring 2 is inserted downward from the inner ring countersunk portion 9; that is, the overlap on the inner side of the ball. Therefore, when the ball 3, falling due to its own weight, is pushed back along the outer ring track groove 5 by the contact force with the inner ring 2 (inner ring countersunk portion 9), no pressure is applied to the ball 3, resulting in damage or breakage. Furthermore, the following situations will not occur: the clearance between the ball 3 and the inner and outer ring track grooves 5 and 8 will not increase, failing to reach the assumed contact angle, or the ball 3 will not cross over the inner and outer ring shoulders 6 and 10.

[0052] An example of assembling the first angular contact ball bearing A and the second angular contact ball bearing B onto an object will be described. In the following description, the parts marked with the prefix "first" are components of the first angular contact ball bearing A, and the parts marked with the prefix "second" are components of the second angular contact ball bearing B.

[0053] First, such as Figure 5 As shown, the second outer ring assembly B' (an assembly that integrally holds the outer ring 1, multiple balls 3, and retainer 4) is inserted into the housing bore 16 provided in the object. At this time, the second outer ring assembly B' is inserted into the housing bore 16 with the upper side of the anti-intermediate axis annular portion 13 of the retainer 4 and the lower side of the intermediate axis annular portion 12. In addition, the outer ring 1 of the second outer ring assembly B' is fitted with an interference fit to the inner circumference of the housing bore 16.

[0054] Next, as Figure 6 As shown, the retaining ring 18 is installed in the retaining ring groove 17 formed on the inner circumference of the housing hole 16. The retaining ring 18 fixes the position of the outer ring 1 of the second outer ring assembly B'. Then, the first outer ring assembly A' is inserted into the portion of the housing hole 16 that is lower than the second outer ring assembly B'. At this time, the first outer ring assembly A' is inserted into the housing hole 16 with the intermediate shaft side annular portion 12 of the retainer 4 on the upper side and the anti-intermediate shaft side annular portion 13 on the lower side. Furthermore, the outer ring 1 of the first outer ring assembly A' is fitted with an interference fit to the inner circumference of the housing hole 16.

[0055] On the other hand, such as Figure 7As shown, the first inner ring 2 is installed on the outer periphery of the shaft 19. At this time, the first inner ring 2 is installed on the outer periphery of the shaft with the inner ring countersunk hole 9 as the upper side and the inner ring shoulder 10 as the lower side. Furthermore, the first inner ring 2 is fitted with an interference fit to the outer periphery of the shaft 19. Then, the first outer ring assembly A' is installed on the outer periphery of the first inner ring 2 from the top. With this installation, the first angular contact ball bearing A is completed. In this embodiment, the outer diameter Rt of the front end of the inner ring countersunk hole 9 of the inner ring 2 is designed to be smaller than the inscribed circle diameter Ri of the ball 3, thus allowing the first outer ring assembly A' to be smoothly installed on the outer periphery of the first inner ring 2.

[0056] After that, as Figure 8 As shown, the second inner ring 2 is inserted into the second outer ring assembly B' from above, with the inner ring countersunk portion 9 as the lower side and the inner ring shoulder 10 as the upper side. At this time, the second inner ring 2 is fitted with an interference fit to the outer periphery of the shaft body 19. Thus, the second angular contact ball bearing B is completed.

[0057] As described above, the first angular contact ball bearing A and the second angular contact ball bearing B can be assembled onto the object.

[0058] exist Figure 8 In the insertion of inner ring 2, such as Figure 9 As shown, at the contact point Z between the ball 3 and the inner ring 2 (inner ring countersunk portion 9), an abutting force is generated toward the center O of the ball. This abutting force can be decomposed into a horizontal component F that pushes the ball 3 back toward the outer ring track groove 5. H And the vertical component F that introduces the ball 3 downwards along the insertion direction of the inner ring 2. V When the contact point Z is at a positive position relative to the intersection point Y at the rotation angle β (the direction in which ball 3 falls), relative to the vertical component F... V Horizontal component F H The ball is large enough to smoothly push the ball 3 back toward the outer ring track groove 5.

[0059] In contrast, such as Figure 13 As shown, when the contact point Z is located at a position with a negative rotation angle β relative to the intersection point Y (a position opposite to the direction in which ball 3 falls), the horizontal component F H 'and vertical component F V 'For the same degree of size, or vertical component F V 'Comparison of horizontal component F H There is a concern that as the inner ring 2 is inserted, the ball 3 may be introduced in the direction of insertion, or the inner ring 2 may not be able to be inserted smoothly.

[0060] Figure 10 express Figure 1The main part of the modified example of the inner ring split-type angular contact ball bearing A shown is shown. This modified example differs from the structure described above only in that the inner ring countersunk portion 9 does not form a tapered surface 11. When the inner ring 2 is inserted relative to the outer ring assembly, the point of contact Z where the balls 3 of the outer ring assembly first abut against the inner ring 2 (inner ring countersunk portion 9) is located on the rotation angle β side, which is more positive than the intersection point Y. Alternatively, the relationship 1.00 < C / D ≤ 2.50 holds between the dimension C of the clearance on the outer side of the ball and the dimension D of the overlap on the inner side of the ball. Therefore, in this modified example, as described above, the balls 3 can be smoothly pushed back towards the outer ring raceway 5 along with the insertion of the inner ring 2, and damage, breakage, or failure to achieve the assumed contact angle due to pressure applied to the balls 3 during this push-back can be prevented. The balls 3 then cross over the shoulders 6 and 10 of the inner and outer rings.

[0061] like Figure 11 , Figure 12 As shown, the aforementioned inner ring split type angular contact ball bearing A can be used as a bearing for automobile transmissions.

[0062] Figure 11 The transmission shown is a fully synchronous gear mechanism that is always engaged. In this transmission, the gear 30 on the input shaft side and the gear 32 on the output shaft 31 side are engaged. The shaft 33, which is driven to rotate by the input shaft and the output shaft 31, is supported by an inner ring split angular contact ball bearing A to enable rotation. This inner ring split angular contact ball bearing A bears not only radial loads from the input shaft or the output shaft 31, but also axial loads.

[0063] Figure 12 The transmission shown is a continuously variable transmission (CVT) capable of outputting the rotational speed of a car engine in a continuously variable manner, with the gear ratio constantly changing. The transmission includes: a torque converter 35 connected to the crankshaft 34 of the car engine; an input shaft 36, through which the rotational speed of the car engine is input; an output shaft 37, arranged parallel to the input shaft 36; a drive-side V-groove pulley 38, rotatably mounted on the outer periphery of the input shaft 36; a driven-side V-groove pulley 39, rotatably mounted on the outer periphery of the output shaft 37; and a V-belt 40 wound between the drive-side V-groove pulley 38 and the driven-side V-groove pulley 39. The input shaft 36 and output shaft 37 are supported by inner-ring separable angular contact ball bearings A, enabling them to rotate. These inner-ring separable angular contact ball bearings A bear not only radial loads from the input shaft 36 or output shaft 37, but also axial loads.

[0064] It should be considered that all the embodiments disclosed herein are merely illustrative and not intended to limit the invention. The scope of the invention is defined by the claims, not by the foregoing description, and is intended to include all modifications equivalent to and within the scope of the claims.

Claims

1. A type of inner ring separable angular contact ball bearing, characterized in that, have: Outer ring (1); The inner ring (2) is coaxially disposed on the radially inner side of the outer ring (1); Multiple balls (3) are circumferentially spaced between the outer ring (1) and the inner ring (2); and Holder (4) holds the plurality of balls (3). On the inner circumference of the outer ring (1), there is an outer ring track groove (5) for the ball (3) to roll into contact, an outer ring shoulder (6) adjacent to one side of the axial direction of the outer ring track groove (5), and an outer ring countersunk hole (7) adjacent to the other side of the axial direction of the outer ring track groove (5) and having an inner diameter larger than that of the outer ring shoulder (6). On the outer periphery of the inner ring (2), there is an inner ring track groove (8) for the rolling contact of the ball (3), an inner ring countersunk hole (9) adjacent to one side of the axial direction of the inner ring track groove (8), and an inner ring shoulder (10) adjacent to the other side of the axial direction of the inner ring track groove (8) and having an outer diameter larger than that of the inner ring countersunk hole (9). When the inner ring (2) is separated, the ball (3) is supported so as not to fall out radially inward from the pocket (15) formed in the retainer (4). With the outer ring (1), the retainer (4), and the ball (3) held together as a single unit, and the point where the center line passing through the contact point (X) and the center (O) of the ball (3) intersects with the surface of the ball (3) as the intersection point (Y), and the rotation angle (β) around the center (O) of the ball (3) from the intersection point (Y) toward the direction in which the ball (3) falls in is set to positive, and the rotation angle (β) from the intersection point (Y) toward the opposite direction is set to negative, when the inner ring (2) is inserted downward from the inner ring countersunk hole (9) side, the contact point (Z) where the ball (3) first abuts against the inner ring countersunk hole (9) is located on the positive side of the intersection point (Y), wherein the contact point (X) is the point between the ball (3) and the outer ring shoulder (6) when the ball (3) falls radially inward due to its own weight. Between dimensions C and D, the relationship 1.00 < C / D ≤ 2.50 holds, where dimension C is the radial clearance between the outer diameter (Ro) of the ball (3) and the bottom of the outer ring track groove (5) when the ball (3) falls radially inward due to its own weight, i.e., the outer side clearance of the ball, and dimension D is the difference between the inner diameter (Ri) of the ball (3) and the outer diameter (Rc) of the inner ring countersunk hole (9) when the inner ring (2) is inserted downward from the inner ring countersunk hole (9), i.e., the inner side overlap of the ball. By abutting the inner ring (2) against the side of the positive rotation angle (β) relative to the intersection point (Y), the ball (3) that has fallen in due to its own weight is pushed back along the outer ring track groove (5). A conical surface (11) is formed on the outer peripheral surface of the inner ring countersunk hole (9), with the outer diameter gradually decreasing as it moves away from the inner ring track groove (8). An axially flat intermediate shaft portion is formed between the inner ring track groove (8) and the conical surface (11), and the intermediate shaft flat portion is continuous with the bottom of the inner ring track groove (8).

2. The inner ring separable angular contact ball bearing according to claim 1, characterized in that, A conical surface (11) is formed on the outer peripheral surface of the inner ring countersunk hole (9). The axial tilt angle α of the conical surface (11) satisfies 0°<α≤30°. The outer diameter of the conical surface (11) gradually decreases as it moves away from the inner ring track groove (8).

3. The inner ring separable angular contact ball bearing according to claim 1 or 2, characterized in that, A solid lubricating film is formed on the outer peripheral surface of the inner ring countersunk portion (9).

4. The inner ring separable angular contact ball bearing according to any one of claims 1 to 3, characterized in that, It is used as a bearing in the transmission of automobiles.

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