JP2003074564A - 4-point contact ball bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a 4-point contact ball bearing which is excellent in heat radiation and hardly brings seizure. SOLUTION: The 4-point contact ball bearing is set so that the radius of curvature of the raceway groove 12 of the outer ring 2 is set to arrange in 55-56.5% as large as the ball diameter. In this way, slide between the balls 3 and the racingway groove 12 of the outer ring 2 becomes small and hence, the heat generation due to the slide is reduced and further, the gap 13 between the balls 3 and the raceway face 12 of the outer ring 2 gets large. Accordingly, the 4-point contact ball bearing is excellent in heat radiation and hardly brings seizure.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a four-point contact ball bearing used for, for example, an electromagnetic clutch or a pulley of an automotive air conditioner. 2. Description of the Related Art Conventionally, as a four-point contact ball bearing of this type, a groove curvature radius of a raceway groove of an outer ring is set to 52% of a diameter of a ball, and a groove curvature radius of a raceway groove of an inner race is set. The diameter of the ball is set to 52%, and the contact ellipse between the ball and the raceway groove is increased to prevent moment resistance and peeling. This four-point contact ball bearing has advantages of light weight, compactness, and low cost. However, in the above-mentioned conventional four-point contact ball bearing, the radius of curvature of the raceway groove of the outer ring is set to 52% of the diameter of the ball, and the raceway groove of the inner race is formed. Since the radius of curvature is set to 52% of the diameter of the ball, the contact area between the ball and the raceway grooves of the inner ring and the outer ring becomes large, and there is a problem that heat is generated due to slip and seizure is easily generated. Was. In particular, when the above-mentioned four-point contact ball bearing is used as a pulley bearing or an electromagnetic clutch of an air conditioner for an automobile, heat is transmitted to the inner ring from the boss of the compressor, so that the temperature of the inner ring tends to increase. When the temperature is lowered, the heat dissipation becomes better. Therefore, how to improve the heat dissipation of the outer ring is a point in preventing image sticking. Therefore, an object of the present invention is to provide a four-point contact ball bearing which has excellent heat dissipation properties and hardly causes seizure. In order to achieve the above object, a four-point contact ball bearing according to the first aspect of the present invention has a ball contacting a raceway groove of an inner ring at two points and a raceway groove of an outer ring. In the four-point contact ball bearing contacting the ball at two points, the radius of curvature of the raceway groove of the outer ring is set to be in a range of more than 55% of the ball diameter and not more than 56.5%. According to the above configuration, the radius of curvature of the raceway groove of the outer ring is set to a value exceeding 55% of the diameter of the ball, so that the contact ellipse between the ball and the raceway groove of the outer race becomes smaller, and And the slip between the outer ring and the raceway groove of the outer ring is reduced, and the temperature rise due to the slip is reduced. In addition, since the radius of curvature of the raceway groove of the outer ring is a value exceeding 55% of the diameter of the ball, it can be formed between the raceway groove of the outer race having a smaller curvature than the conventional example and the ball. The gap is increased, and the heat dissipation between the ball and the raceway groove of the outer ring is improved, so that the temperature rise of the outer ring, the ball, and the inner ring can be reduced. Further, since the radius of curvature of the raceway groove of the outer race is not more than 56.5% of the diameter of the ball, the contact surface pressure between the raceway of the outer race and the ball does not become excessively large and the peeling life is shortened. Absent. In particular, when the above four-point contact ball bearing is used as a pulley bearing or an electromagnetic clutch of an air conditioner,
The heat from the air conditioner is transferred to the inner ring and the inner ring is about to get hot. However, since the radius of curvature of the raceway groove of the outer ring is larger than the conventional range of 55% or more and 56.5% or less of the diameter of the ball, the contact area between the ball and the raceway groove of the outer ring is small, and the slippage is small. And the gap between the outer ring and the ball becomes large. Therefore, heat is effectively radiated from the outer ring side of the four-point contact ball bearing. Therefore, seizure hardly occurs in the four-point contact ball bearing, and the life is extended. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments. FIG. 1 is a sectional view of a four-point contact ball bearing according to an embodiment of the present invention. In this embodiment, a plurality of balls 3, 3, ... between the raceway groove 11 of the inner ring 1 and the raceway groove 12 of the outer ring 2 are provided.
Are arranged at predetermined intervals in the circumferential direction.
.. Are held by a holder 5. Seal members 6, 6 are fixed to both ends of the outer ring 2 in the axial direction, and the seal lips 7, 7 of the seal members 6, 6 are in sliding contact with recesses formed at both axial ends of the inner ring 1. The raceway groove 11 of the inner ring 1 has a left portion 11B on the left side in FIG. 1 of a radial plane C of the bearing passing through the center P0 of the ball 3 and a right portion 1 on the right side of the plane C.
1A. The left portion 11B contacts the ball 3 at a point P3, and the right portion 11A contacts the ball 3 at a point P4. Track groove 11 of the inner ring 1
Each of the left portion 11B and the right portion 11A has a radius of curvature of 52% of the diameter of the ball 3. On the other hand, the raceway groove 12 of the outer race 2 also has a left portion 12B on the left side in FIG. 1 of a radial plane C of the bearing passing through the center P0 of the ball 3, and a right portion on the right side of the plane C. 12A. And the left part 1
2B comes into contact with the ball 3 at a point P1, and the right portion 12A
Is in contact with the ball 3 at a point P2. The raceway groove 12 of the outer race 2 has a radius of curvature of 56% of the diameter of the ball 3 in both the left portion 12A and the right portion 12B. As described above, since the radius of curvature of the left side portion 12A and the right side portion 12B of the raceway groove 12 of the outer race 2 is 56% of the diameter of the ball 3, the distance between the raceway groove 12 and the outer surface of the ball 3 is increased. A large gap 13 is formed between them. That is, since the radius of curvature of the raceway groove 12 of the outer race 2 is larger than the radius of curvature of the raceway groove 11 of the inner race 1, the gap 13 is formed between the raceway groove 11 of the inner race 1 and the inner surface of the ball 3. It is larger than the gap that can be made. The contact angle θ2 between the ball 3 and the raceway groove 11B is the same as the contact angle between the ball 3 and the raceway groove 11A. The contact angle θ1 between the ball 3 and the raceway groove 12A is the same as the contact angle between the ball 3 and the raceway groove 12B. According to the four-point contact ball bearing of this embodiment,
The radius of curvature of the raceway groove 12 of the outer race 2 is set to 56.0% of the diameter of the ball 3. Therefore, the contact ellipse between the ball 3 and the raceway groove 12 of the outer ring 2 becomes small, and the ball 3
And slip between the outer race 2 and the raceway groove 12 is reduced,
The temperature rise due to slip is reduced. Further, since the radius of curvature of the raceway groove 12 of the outer race 2 is set to 56.0% of the diameter of the ball 3, the raceway groove 12 of the outer race 2 having a smaller curvature than the conventional example, The gap 13 formed between the ball 3 and the ball 3 is increased, the heat radiation between the ball 3 and the raceway groove 12 of the outer ring 2 is improved, and the temperature rise of the outer ring 2 and the ball 3, and thus the inner ring 1 is reduced. can do. In particular, when the above four-point contact ball bearing is used as a pulley bearing or an electromagnetic clutch of an air conditioner, heat from a boss of a compressor of the air conditioner is transmitted to the inner ring 1, and the inner ring 1 tends to become hot. However, the radius of curvature of the raceway groove 12 of the outer ring 2 is 5 times the diameter of the ball 3.
6%, which is larger than that of the related art, so that the contact area between the ball 3 and the raceway groove 12 of the outer ring 2 is small, slippage is less likely to occur, and the gap between the outer ring 2 and the ball 3 13 is increased. Therefore, the temperature of the outer ring 2 of the four-point contact ball bearing is lowered, and heat is effectively radiated from the outer ring 2 side. Therefore, seizure hardly occurs in the four-point contact ball bearing, and the life is extended. In the above embodiment, the radius of curvature of the raceway groove 12 of the outer race 2 is set to 56% of the diameter of the ball 3.
The same effect can be obtained by setting the radius of curvature of the raceway groove 12 of the outer race 2 to be within a range of more than 55% of the diameter of the ball 3 and not more than 56.5%. In the above embodiment, the curvature of the raceway groove 11 of the inner race 1 is set to 52%. However, the present invention is not limited to this, and the curvature of the raceway groove 11 of the inner race 1 may be set to 51.5%. As is apparent from the above, according to the four-point contact ball bearing of the first aspect of the invention, the radius of curvature of the raceway groove of the outer ring is set to a value exceeding 55% of the diameter of the ball. So
The contact ellipse between the ball and the raceway groove of the outer ring is reduced, the slip between the ball and the raceway groove of the outer race is reduced, and the temperature rise due to the slip is reduced. According to the four-point contact ball bearing of the first aspect of the present invention, the radius of curvature of the raceway groove of the outer ring is 5 times the diameter of the ball.
Since the value exceeds 5%, the gap formed between the raceway groove of the outer race and the ball is increased, the heat radiation between the raceway and the raceway groove is improved, and the raceway groove and the raceway of the ball are improved. Temperature rise can be reduced. Further, according to the four-point contact ball bearing of the first aspect of the present invention, since the radius of curvature of the raceway groove of the outer ring is 56.5% or less of the ball diameter, the contact surface pressure between the raceway of the outer ring and the ball is reduced. It does not become excessive and the peeling life is not shortened.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a four-point contact ball bearing according to an embodiment of the present invention. [Description of Signs] 1 inner ring, 2 outer ring, 3 balls, 11, 12 raceway groove.

Claims (1)

Claims: 1. A four-point contact ball bearing in which a ball contacts a raceway groove of an inner race at two points and contacts a raceway groove of an outer race at two points. A four-point contact ball bearing, wherein the radius is set in a range of more than 55% and less than 56.5% of a ball diameter.