JPH089452Y2 - Ceramic angular contact ball bearings for turbochargers - Google Patents

Description

TECHNICAL FIELD The present invention relates to a ceramic angular contact ball bearing for turbochargers such as automobile engines.

Conventional technology and problems to be solved In the cage of rolling bearings for turbochargers, the ferrous material containing Cr-Mo-Ni, which has a proven track record for aircraft, is currently used.
AMS6414 with Ag plating is used. The reason is that it has heat resistance, has high strength, and has some self-lubricating property by Ag plating. This cage was sufficiently usable from the viewpoint of seizure resistance when it was rotated constantly as in an aircraft. However, in a case where rapid rising acceleration / deceleration of rotation occurs frequently like a turbocharger, there is a problem because there is an upper limit on the change in rotation speed and the maximum rotation speed. Also,
Due to the high density of about 8 g / cm ₃ , there were problems such as unbalance of the cage and delay of responsiveness because a large amount of energy was required for the start of rotation.

It is also considered to use a full ball bearing as a bearing for a turbocharger, but in the case of a full ball bearing, the balls move in opposite directions at the ball-to-ball contact part, so the relative speed between the balls is It becomes twice the relative speed of the cage and balls when there is a cage, and wear becomes very large without the lubricant, making it unsuitable for long-term use.

An object of the present invention is to provide a ceramic bearing for a turbocharger, which solves the above problems.

Means for Solving the Problems A ceramic bearing for a turbocharger according to the present invention comprises an inner ring made of heat-resistant steel provided with a counterbore, an outer ring made of steel, a plurality of ceramic balls and a ball cage, and The container is an annular body integrally formed by shaving using a resin having an imide bond in the main chain or a polyetheretherketone resin as a material, and the annular body has a plurality of cylindrical shapes extending from the inner peripheral surface to the outer peripheral surface. Is formed as a pocket for holding balls, the outer peripheral surface of the annular portion at both ends of the cage pocket is guided to the inner peripheral surface of the outer ring, respectively, and the pitch circle diameter of the cage is the ball pitch. Larger than circle diameter,
The outer peripheral surface of the annular portion of the cage has a surface roughness of 1 z or less.

Action In the ball bearing incorporated in the turbocharger, especially when the engine is suddenly stopped from the high speed rotation state,
The temperature of the component parts of the ball bearing rises sharply, and the temperature rise of the inner ring, which is strongly affected by the exhaust heat via the turbine and the rotating shaft, becomes particularly remarkable. Therefore, the life of the ball bearing tends to be shortened due to the decrease in hardness of the inner ring. In the case of the ball bearing according to the present invention, since the inner ring is made of heat-resistant steel, hardness is less likely to decrease due to temperature rise, the balls are made of highly heat-resistant ceramic, and the cage has a resin having an imide bond in its main chain. Combined with the fact that it is made of heat-resistant engineering plastic called polyether ether ketone resin, the heat resistance of the entire ball bearing is improved. Since there is a cage, the relative speed of the balls is halved compared to a full ball bearing, and the wear of the balls is small and the durability is improved in combination with the fact that the balls are made of ceramic. Since the pocket of the cage that holds the balls is a cylindrical hole, no sharp edges are generated at the inner and outer peripheral ends of the pocket, and therefore the ball is not caught by the inertial force, and the durability of the cage is improved. improves. Since the balls are made of ceramic and the cage is made of heat-resistant engineering plastic, there is no metal-to-metal contact, and the heat-resistant engineering plastic can contain a self-lubricating material such as fluororesin, causing oil film breakage. However, seizure can be prevented, and as a result, the durability of the balls and the cage is improved.

Thus, the inner ring is made of heat-resistant steel, the balls are made of ceramic, the cage is made of a resin having an imide bond in the main chain or polyetheretherketone resin, and the cage pocket is cylindrical. The hole-like shape has the effect of improving heat resistance and durability.

Since the inner ring is made of heat-resistant steel and the cage is made of heat-resistant engineering plastic, the responsiveness is improved by reducing the inertial mass of the cage, and the responsiveness is also improved by decreasing the viscosity of the lubricating oil. That is, first,
Density of heat-resistant engineering plastic is about 1.5g / c
Since it is 1/5 or less of metal at m ₃ , the cage becomes lightweight, its inertial mass becomes small, and its responsiveness to a rapid rise of the rotation speed is improved. Furthermore, since the inner ring and the cage are made of heat-resistant material, it is possible to raise the temperature of the lubricating oil supplied to the ball bearings, and the higher temperature of the lubricating oil reduces the viscosity of the lubricating oil. The resistance against rotation of the container is reduced, and the responsiveness is improved.
Since the cage is integrally formed by shaving, it is possible to improve the molding accuracy and surface roughness compared to the case where only injection molding is performed, and the outer peripheral surface of the annular part at both ends of the cage pocket. Has a surface roughness of 1 z or less, the torque required to rotate the cage is small, and the responsiveness is improved. Since the cage made of heat-resistant engineering plastic has a density of 1/5 or less of that of metal, the unbalance can be reduced to 1/5 even if a cage is manufactured with the same accuracy as a metal cage. . The cage integrally formed by the shaving process can improve the molding accuracy and the surface roughness as described above, and the imbalance can be reduced also from this point. Then, since the imbalance of the cage is reduced, the rotation performance is improved and the responsiveness is also improved.

In this way, the inner ring is made of heat-resistant steel, the cage is made of a resin having an imide bond in the main chain or polyetheretherketone resin, and the cage is integrally formed by scraping to form an annular portion thereof. Since the surface roughness of the outer peripheral surface is 1 z or less, the effect of improving the responsiveness is exhibited.

The outer peripheral surface of the annular portion of the cage is guided by the inner peripheral surface of the outer ring, respectively, and the pitch circle diameter of the cage is larger than the pitch circle diameter of the balls, so the inner peripheral surface of the cage is the outer peripheral surface of the inner ring. Away from the outside. For this reason, the contact point (sliding point) between the cage and the balls becomes closer to the inner peripheral surface of the cage, and comparison is made between the cage and the inner ring, especially between the part where the counterbore is provided. A large space is formed. Further, since the pocket of the cage is a cylindrical hole, a relatively large space is formed between the balls on the inner and outer peripheral sides of the cage except for the contact points with the balls of the cage. . Therefore, the lubricating oil easily flows into the cage from the outside of the bearing through the relatively large space between the cage and the inner ring and the relatively large space between the inner peripheral side of the cage and the balls. , Through a relatively large space between the outer peripheral side of the cage and the balls, easily flows out of the inside of the cage, and is supplied between the outer peripheral surface of the cage and the inner peripheral surface of the outer ring. Is discharged to. That is, it becomes easy for the lubricating oil to flow into and out of the cage, and excessive lubricating oil does not stay in the cage, improving lubricity.

In this way, the counterbore is provided in the inner ring, the pocket of the cage is a cylindrical hole, and the outer peripheral surface of the annular portion of the cage is guided by the inner peripheral surface of the outer ring to retain the cage. Since the pitch circle diameter is larger than the pitch circle diameter of the balls, the effect of improving lubricity is exhibited.

By improving the lubricity as described above, abrasion of each part of the ball bearing is reduced, seizure is prevented, and durability is improved also from this point.

By improving the lubricity as described above, the amount of lubricating oil supplied to the ball bearing can be reduced, the temperature of the lubricating oil can be increased, and its viscosity can be reduced.
This improves the responsiveness as described above. Also,
As described above, excess lubricating oil does not stay in the cage, torque loss due to stirring resistance of the lubricating oil is reduced, rotation resistance of the cage does not increase, and responsiveness is improved. To do. That is, the responsiveness is also improved by improving the lubricity.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

The drawing shows a ceramic angular contact ball bearing for a turbocharger of an automobile engine, which has a cage consisting of an inner ring (1), an outer ring (2), a ball (3) and a cage (4). is there.

The inner ring (1) and the outer ring (2) are made of heat resistant steel such as AISI-M50. A counterbore (5) is formed in the inner ring (2) to form an angular ball bearing. No counterbore is formed in the outer ring (2). The balls (3) are made of a ceramic such as silicon nitride. The cage (4) is made of, for example, polyamide-imide resin,
It is made of a resin having an imide bond in the main chain such as a polyimide resin or a heat resistant engineering plastic such as a polyether ether ketone resin.

The cage (4) is a machined die, and is made of an annular body integrally formed by cutting. The annular body of the retainer (4) is formed with a plurality of cylindrical holes extending from the inner peripheral surface to the outer peripheral surface, and these holes serve as pockets (6) for retaining the balls (3). The cage (4) is used as an outer ring guide in order to reduce rasping motion and vibration due to unbalance at high speed rotation, and the outer peripheral surface of the annular portion (4a) on both ends of the pocket (6) is the outer ring (2). ) Are each guided on the inner surface. Since the cage (4) is an outer ring guide, the cage (4)
The pitch circle (C1) is located outside (outer ring (2) side) of the pitch circle (C2) of the ball (3). That is, the pitch circle diameter of the cage (4) is larger than the pitch circle diameter of the balls (3). The guide surface on the outer periphery of the annular portion (4a) of the cage (4) has a 10-point average roughness of 1.0z to prevent seizure due to oil film breakage due to poor surface accuracy during sliding contact with the outer ring (2). It is processed as follows. In order to secure such guide surface precision and prevent damage at high speed rotation due to wall thickness imbalance, the cage (4) is manufactured with high precision by shaving.

The above ball bearings include inner ring (1), outer ring (2), balls (3)
Since the cage (4) and the cage (4) are made of a heat-resistant material, the heat resistance is high, and stable performance is exhibited for a long period of time even when the cage (4) is provided on the turbine side of the turbocharger that is exposed to a high temperature during use.

Since the pocket (6) of the cage (4) for holding the balls (3) is a cylindrical hole, the inner peripheral end (6a) of the pocket (6)
Also, no sharp edge is generated at the outer peripheral end (6b), and therefore, the ball (3) is not caught by the inertial force, and the durability of the retainer (4) is improved.

Since the cage (4) is the outer ring guide and the pitch circle diameter of the cage (4) is larger than the pitch circle diameter of the balls (3), the inner peripheral surface of the cage (4) is the inner ring (1). ) Away from the outer peripheral surface. Therefore, the contact point (sliding point) (A) between the cage (4) and the ball (3) is close to the inner peripheral surface of the cage (4), and the cage (4) and the inner ring (1) are A relatively large space for allowing the lubricating oil to flow into the inside of the retainer (4) is formed between the retainer (4) and the portion where the counterbore (5) is provided. Further, since the pocket (6) of the cage (4) is not a concave spherical surface corresponding to the convex spherical surface of the ball (3) but a cylindrical hole, the cage except for the contact point (4). A relatively large space for inflow and outflow of the lubricating oil is formed between the balls (3) and the inner and outer peripheral sides of (4). For this reason, it becomes easy for the lubricating oil to flow into and out of the cage (4), and excessive lubricating oil does not stay in the cage (4), and the lubricity Is improved.

Effect of the Invention According to the ceramic angular contact ball bearing for a turbocharger according to the present invention, as described above, both heat resistance and durability, responsiveness, and lubricity are improved, and durability is improved by improving lubricity. The responsiveness is further improved. Since the heat resistance and the durability are improved, stable performance is exhibited for a long period of time even when the turbocharger is provided on the turbine side which is particularly exposed to a high temperature during use.

[Brief description of drawings]

The drawing is a longitudinal sectional view of a ceramic angular contact ball bearing for a turbocharger showing an embodiment of the present invention. (1) …… inner ring, (2) …… outer ring, (3) …… ball,
(4) …… Cage, (4a) …… Annulus, (5) …… Counterbore, (6) …… Pocket.

 ─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-63-149409 (JP, A) JP-A-57-190121 (JP, A) JP-A-49-61539 (JP, A) Actual development Sho-59- 70929 (JP, U) Actually opened 63-59218 (JP, U) Actually opened 60-7420 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A heat-resistant steel inner ring (1) provided with a counterbore (5), a steel outer ring (2), a plurality of ceramic balls (3) and a cage (4) for the balls (3). ), The cage (4) is an annular body integrally formed by a shaving process using a resin having an imide bond in the main chain or a polyetheretherketone resin as a raw material. A plurality of cylindrical holes are formed in the outer peripheral surface to form pockets (6) for holding balls (3), and an annular portion (4a) at both ends of the pocket (6) of the cage (4) is formed. The outer peripheral surface is guided by the inner peripheral surface of the outer ring (2), the pitch circle diameter of the cage (4) is larger than the pitch circle diameter of the ball (3), and the outer periphery of the annular portion (4a) of the cage (4). Surface roughness
Ceramic angular contact ball bearings for turbochargers characterized by being set to 1z or less.