Deep groove ball bearing

Abstract

To provide a deep groove ball bearing that eliminates a load on a holder caused by advance / delay of a ball, and eliminates interference between the holder and an outer diameter surface of an inner ring, and between the holder and an inner diameter surface of an outer ring.SOLUTION: A deep groove ball bearing comprises an inner ring having an inner ring raceway surface on an outer periphery, an outer ring having an outer ring raceway surface on an inner periphery, a plurality of balls 4 rolling between the inner ring raceway surface and the outer ring raceway surface, and a holder 5 holding the balls 4 at regular intervals in a circumferential direction, where a lower limit value of a circumferential pocket gap formed between a pocket 50 of the holder 5 that houses the ball 4 and the ball 4 is set to 0.1 mm, and an upper limit thereof to [0.09×used ball diameter-0.007] (mm).SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a deep groove ball bearing, and more particularly to a deep groove ball bearing suitable for use in a transmission. [Background technology]

[0002] Deep groove ball bearings have deep arc-shaped grooves on the raceways of both the inner and outer rings, and can withstand radial loads, axial loads in both directions, or combined loads that are a combination of these, making them suitable for high-speed rotation. For this reason, deep groove ball bearings are the most widely used of all rolling bearings.

[0003] Meanwhile, deep groove ball bearings used in transmissions use a stamped cage, which is also used in the deep groove ball bearing of Patent Document 1, due to compatibility issues with transmission oil, and holds the balls as rolling elements at equal intervals between the inner and outer rings.

[0004] The orbital speed of each of the balls held in the pockets of the cage as rolling elements varies depending on the ball.

[0005] In particular, when applied to transmissions, a phenomenon called ball lead-lag occurs, in which the faster rotating balls and the slower rotating balls pull on the cage. To avoid the load on the cage caused by this phenomenon called ball lead-lag, it is necessary to ensure a sufficient circumferential gap between the pockets and the balls. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2013-160376 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, if the circumferential gap between the pockets in the cage and the balls is set large, the amount of radial movement of the cage also increases, which raises concerns that the cage may interfere with the outer diameter surface of the inner ring or the inner diameter surface of the outer ring, resulting in load being placed on the cage due to this interference. Because the circumferential gap between the cage and the balls and the amount of radial movement of the cage are in conflict with each other, changing one in an advantageous direction will result in a disadvantage to the other.

[0008] Therefore, in some cases, it may be necessary to change the cage design or the bearing size.

[0009] Therefore, this invention aims to provide a deep groove ball bearing that is particularly suitable for transmission applications, by specifying upper and lower limits for the circumferential pocket gaps formed between the pockets of the cage and the balls, without changing the cage design or bearing size, thereby eliminating the load on the cage due to the advance / delay of the balls and eliminating interference with the cage by the inner and outer rings. [Means for solving the problem]

[0010] In order to solve the above-mentioned problems, the present invention provides a deep groove ball bearing comprising an inner ring having an inner ring raceway surface on its outer circumference, an outer ring having an outer ring raceway surface on its inner circumference, a plurality of balls rolling between the inner ring raceway surface and the outer ring raceway surface, and a retainer that holds the balls at regular intervals in the circumferential direction, wherein the lower limit of the circumferential pocket gap formed between the pockets that accommodate the balls in the retainer and the balls is set to 0.1 mm and the upper limit is set to [0.09 x ball diameter used - 0.007] (mm).

[0011] The pockets of the cage that house the balls and the circumferential pocket gaps formed between the balls vary with the operating temperature, so in this invention it refers to the gap at the maximum normal operating temperature of 100°C.

[0012] In addition, since the energy with which the balls collide with the pockets of the cage differs depending on the mass, the size of the circumferential pocket gap in this invention is set on the assumption that the balls are steel balls.

[0013] In addition, the size of the circumferential pocket gap in this invention is determined by using a stamped retainer formed by punching out cold-rolled steel plate (SPCC), but the material may be stainless steel (SUS), metal such as copper (Cu), silver (Ag), or resin.

[0014] The band width of the cage is set in the range of 0.2 x ball diameter (mm) to 0.6 x ball diameter (mm). Below 0.2 x ball diameter (mm), the cage movement becomes too large, causing contact between the cage and the raceway. Above 0.6 x ball diameter (mm), the clearance between the cage and the outer diameter surface of the inner ring, and the clearance between the cage and the inner diameter surface of the outer ring, become too small, causing contact between the cage and the inner ring, or the cage and the outer ring. Effect of the Invention

[0015] As described above, this invention can eliminate the load on the cage due to the advance / delay of the balls by setting the lower limit of the circumferential pocket gap formed between the pockets that accommodate the balls in the cage in a deep groove ball bearing and the balls to 0.1 mm and the upper limit to [0.09 x ball diameter used - 0.007] (mm). Also, in this invention, by specifying the circumferential pocket gap in the deep groove ball bearing, the amount of movement of the cage can also be specified, eliminating interference between the cage and the outer diameter surface of the inner ring, and between the cage and the inner diameter surface of the outer ring. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0017] 1 and 2, deep groove ball bearing 1 comprises an inner ring 2 having an inner ring raceway 2a on its outer periphery, an outer ring 3 having an outer ring raceway 3a on its inner periphery, and a plurality of balls 4 that roll between the inner ring raceway 2a and the outer ring raceway 3a. The balls 4 are housed in pockets 50 of a cage 5 and are held at regular intervals in the circumferential direction.

[0018] In the embodiment shown in Figs. 1 and 2, a cage 5 which is stamped out from a steel plate using a die is used.

[0019] This punched cage 5, as shown in the perspective view of Figure 3, is formed by stacking two punched annular cage halves 51 face to face in the axial direction as shown in Figure 4, and joining them together with rivets 53 inserted through rivet holes 52.

[0020] The retainer half 51 is an annular body in which spherical shell-shaped plate portions 51a, whose inner surfaces form half of the pockets 50, and flat plate portions 51b, located between adjacent pockets 50, are arranged alternately in the circumferential direction, and the flat plate portions 51b are provided with rivet holes 52 for overlapping the retainer halves 51 face to face in the axial direction and joining them with rivets 53.

[0021] The cage 5, which is made by stacking two cage halves 51 facing each other in the axial direction, has pockets 50 for holding the balls 4 provided at equal intervals in the circumferential direction, and the inner surface of each pocket 50 is formed into a concave spherical shape.

[0022] As shown in FIG. 5, the inner diameter D1 of the pocket 50 of the cage 5 is formed to be larger than the diameter D2 of the ball 4 (D1>D2), and a gap is provided between the inner diameter surface of the pocket 50 and the ball 4.

[0023] In the present invention, the circumferential gap formed between the inner diameter surface of the pocket 50 and the ball 4 is called a circumferential pocket gap s (FIG. 6).

[0024] The circumferential pocket gap s in this invention can be measured as follows.

[0025] First, as shown in Fig. 7, a load is applied in the direction of the arrow from one or both sides of the width faces of the inner ring 2 and the outer ring 3, so that the balls 4 are constrained by the inner ring raceway surface 2a and the outer ring raceway surface 3a. Next, with the balls 4 in a constrained state, the cage 5 is moved in the circumferential direction (the direction of the arrow in Fig. 8) from the side of the bearing to measure the amount of circumferential movement of the cage 5. In other words, since the circumferential pocket gap s formed between the pockets 50 of the cage 5 and the balls 4 is as shown in Fig. 6, the cage 5 can be moved once to the left or right to its limit and then measured as the amount of movement in the opposite direction.

[0026] The orbital speed of the balls 4 housed in the pockets 50 of the retainer 5 varies depending on each ball 4. Some balls 4 rotate fast and some balls 4 rotate slow. The fast-rotating balls 4 and the slow-rotating balls 4 pull on the retainer 5 against each other, creating a phenomenon called "advance-lag" of the balls 4.

[0027] This phenomenon called the lead / lag of the balls 4 refers to the phase difference between the balls 4 that occurs when each ball 4 moves in a direction that reduces the circumferential pocket gap s during bearing rotation.

[0028] If there is a circumferential pocket gap s between the pockets 50 of the cage 5 and the balls 4 accommodated in the pockets 50, the cage 5 moves in the radial direction due to the circumferential pocket gap s during bearing rotation.

[0029] When the cage 5 moves in the radial direction, the clearance c between the cage 5 and the outer diameter surface of the inner ring 2 and the clearance d between the cage 5 and the inner diameter surface of the outer ring 3 decrease.

[0030] Therefore, if the circumferential pocket gap s is set large, the clearances c and d disappear, and the cage 5 comes into contact with the outer diameter surface of the inner ring 2 or the inner diameter surface of the outer ring 3, and a load is applied to the cage 5.

[0031] On the other hand, if the circumferential pocket gap s is too small, a load is applied to the cage 5 due to the advance / delay of the balls 4.

[0032] For this reason, in this invention, by setting lower and upper limits for the circumferential pocket gap s, the load on the retainer 5 due to the advance / delay of the balls 4 is eliminated, and even if the retainer 5 moves radially due to the circumferential pocket gap s, the clearance c between the retainer 5 and the outer diameter surface of the inner ring 2 and the clearance d between the retainer 5 and the inner diameter surface of the outer ring 3 are maintained.

[0033] In the present invention, the lower limit of the circumferential pocket gap s is 0.1 mm, which is determined in consideration of manufacturing tolerances and safety factors, so that no load is generated on the cage 5 due to the advance / delay of the balls 4.

[0034] The width W (Fig. 1) of the cage 5 is set in the range of 0.2 x ball diameter to 0.6 x ball diameter (mm). Below 0.2 x ball diameter (mm), the amount of movement of the cage 5 becomes large, causing the cage 5 to come into contact with the outer ring 3 or the inner ring 2. Above 0.6 x ball diameter (mm), the clearance c between the cage 5 and the outer diameter surface of the inner ring 2 and the clearance d between the cage 5 and the inner diameter surface of the outer ring 3 become small, causing the cage 5 to come into contact with the inner ring 2 or the cage 5 to come into contact with the outer ring 3.

[0035] The relationship between the circumferential pocket gap s required to ensure the clearances c and d with the cage 5 for various sizes (1 / 4 to 19 / 32 inches) of balls 4 used in transmission bearings is as shown in Figure 9. An approximation formula was obtained from the plot in Figure 9, and the upper limit of the circumferential pocket gap s was calculated as [0.09 x ball diameter used - 0.007] (mm).

[0036] The clearances c and d for various sizes of balls 4 used in a transmission bearing at the upper and lower limit values ​​of the circumferential pocket gap s are as shown in FIG.

[0037] In the above embodiment, the cage 5 is formed by punching out a cold rolled steel plate (SPCC), but the material may be stainless steel (SUS) or metal such as copper (Cu) or silver (Ag). The cage 5 may also be made of resin.

[0038] This invention is not limited to the above-described embodiments, and can of course be embodied in various other forms without departing from the spirit of the invention. The scope of the invention is indicated by the claims, and further includes the equivalent meanings set forth in the claims, and all modifications within the scope of the claims. [Brief description of the drawings]

[0039] [Figure 1] 1 is a partially cutaway perspective view of a deep groove ball bearing according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a vertical sectional view of the deep groove ball bearing of FIG. [Diagram 3] 2 is a perspective view showing a retainer half which is a constituent member of the retainer used in the deep groove ball bearing of FIG. 1. [Figure 4] 4 is a perspective view of a cage used in a deep groove ball bearing of the present invention assembled from the cage halves of FIG. 3. [Diagram 5] FIG. 4 is an enlarged view showing the relationship between the inner diameter of the pocket of the cage and the diameter of the ball. [Figure 6] 4 is an enlarged view showing a circumferential pocket gap formed between a pocket of the cage and a ball. FIG. [Figure 7] 5A to 5C are partial vertical cross-sectional views showing a procedure for measuring a circumferential pocket gap. [Figure 8] FIG. 2 is a side view of a deep groove ball bearing showing a state in which a circumferential pocket gap is measured. [Figure 9] 4 is a graph showing the relationship between ball diameter and circumferential pocket gap. [Figure 10] 11 is a graph showing the relationship between ball diameter and clearance at upper and lower limit values ​​of the circumferential pocket gap. [Explanation of symbols]

[0040] 1: Deep groove ball bearing 2: Internal 2a: Outer raceway surface 3: Outer ring 3a: Outer ring raceway surface 4: Ball 5: Retainer 50:Pocket s: Circumferential pocket gap c, d: Clearance

Claims

1. This deep groove ball bearing comprises an inner ring having an inner ring raceway surface on its outer circumference, an outer ring having an outer ring raceway surface on its inner circumference, a plurality of balls rolling between the inner ring raceway surface and the outer ring raceway surface, and a retainer that holds the balls at regular intervals in the circumferential direction, characterized in that the lower limit of the circumferential pocket gap formed between the pockets in the retainer that accommodate the balls and the balls is set to 0.1 mm, and the upper limit is set to [0.09 x ball diameter used - 0.007] (mm).

2. 2. A deep groove ball bearing as claimed in claim 1, wherein said balls are made of steel.

3. 2. A deep groove ball bearing according to claim 1, wherein the material of said cage is a metallic material.

4. 3. The deep groove ball bearing according to claim 1, wherein the width of the retainer is (0.2×ball diameter to 0.6×ball diameter) mm.

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