JP5327039B2 - Rolling bearing - Google Patents

Description

  The present invention relates to a rolling bearing suitable for use in, for example, a motor support of a vehicle transmission, a hybrid vehicle, an electric vehicle, or a fuel cell vehicle, or a gear support directly connected to the motor.

  As a conventional rolling bearing used in an automobile transmission, a rolling bearing 50 shown in FIG. 3 is an inner ring 51, an outer ring 52, and a plurality of rolling elements that are relatively rotatably disposed between the inner and outer rings 51, 52. The ball | bowl 53 and the iron corrugated press holder | retainer 54 which hold | maintains the ball | bowl 53 so that rolling is possible are provided. The inner ring 51 has an inner ring raceway surface 51a at the center of the outer diameter surface, and the outer ring 52 has an outer ring raceway surface 52a at the center of the inner diameter surface.

  As shown in FIG. 4, the iron corrugated press cage 54 used for the rolling bearing 50 is used for a non-separable type bearing, and has two annular shapes having recesses 58 and 59 for forming a pocket 57. These metal members 60 and 61 are combined and coupled by a rivet 62. The curvature of the rolling element guide surface in the pocket 57 of the iron corrugated press cage 54 is set to be smaller than the curvature of the surface of the ball 53, and an oil film is formed between the iron corrugated press cage 54 and the ball 53 by lubricating oil. By doing so, wear of these sliding portions is suppressed.

  However, when used with light load and high speed rotation, the driving force between the inner ring and the rolling element becomes extremely smaller than the driving force between the outer ring and the rolling element due to the influence of centrifugal force. Revolution slip, that is, so-called skidding may occur. And if this skidding occurs excessively, the oil film between the rolling element and the raceway surface breaks, thereby causing metal contact and metal wear, which ultimately leads to damage such as seizure. become. In addition, when skidding occurs, metal contact occurs between the rolling elements and the metal cage, and metal friction occurs, which may reduce the life of the rolling bearing.

  Normally, the rolling element moves in a rolling bearing by being driven by a rotating wheel in a load zone and rolling, and in a non-load zone, it re-enters the load zone while rotating by inertia due to rolling in the load zone. When the load is small, only a small number of rolling elements are loaded, and the load zone becomes narrow and the non-load zone becomes wide. Therefore, the ratio of the time to rotate by inertia increases compared to the time driven in the load zone. At this time, both the rolling element and the cage revolve. However, since the cage always rotates in conjunction with the rolling element in the load zone, the rolling element in the non-load zone is pushed by the cage and revolves. At the same time, since the rolling element comes into contact with the guide surface of the cage, the rotation is decelerated.

  For this reason, when re-entering into the load zone, the balance between the rotation speed of the rolling elements and the rotation speed of the driving wheels is lost, and slipping easily occurs between the driving wheels and the rolling elements. Further, when the rotation speed increases, a force that is pressed against the rolling element by the centrifugal force acts, and the frictional force between the outer ring and the rolling element increases, so that the driving wheel and the rolling element are easily slipped. For this reason, when the load is small, the higher the rotation speed, the easier the skidding of the rolling elements.

On the other hand, against the backdrop of market needs such as weight reduction and cost reduction, the demand for rolling bearings using synthetic resin cages as a countermeasure against skidding is increasing year by year.
Such a cage made of a synthetic resin is often processed into a crown shape as shown in FIG. 6 because of its good incorporation into the bearing.

  The crown-shaped cage 14 includes an annular shape portion 16 and a plurality of pillar portions 17 extending in the axial direction from the annular shape portion 16, and a pocket 15 is formed by the adjacent pillar portions 17 and 17. Yes.

  As shown in FIG. 5, the rolling bearing 10 incorporating such a synthetic resin crown-shaped cage 14 is a rolling element between the inner ring raceway surface 11 a of the inner ring 11 and the outer ring raceway surface 12 a of the outer ring 12. A plurality of balls 13 are arranged in a rollable state. The cage 14 is incorporated between the inner ring 11 and the outer ring 12 by elastically deforming and expanding the claws 17 a provided at the end portions in the axial direction of the column parts 17 and inserting the balls 13 into the pockets 15. It is rotatably held in a form that is relatively guided by the balls 13.

  As a material for the cage, a material based on an aliphatic aliphatic polyamide resin such as polyamide 66 or polyamide 46 which is lighter in weight and superior in mechanical properties than a metal material is frequently used. The reduction in the coefficient of friction between the balls 13 and the rolling element guide surfaces of the cage 14 suppresses the deceleration of the rotation of the balls 13 in the non-load zone, resulting in damage due to skidding of the balls 13. In addition, the seizure resistance is excellent, and the bearing life can be extended.

  Various improvements of resins and heat stabilizers have been proposed. For example, a synthetic resin cage in which an elastomer is blended with polyamide 46 and reinforced with a reinforcing material (see, for example, Patent Document 1), and a reinforcing material is added to polyamide. In addition, a synthetic resin cage (for example, see Patent Document 2) containing a combination of a copper heat stabilizer and an organic heat stabilizer, and at least an amine heat stabilizer and a phenol heat stabilizer in the synthetic resin. A synthetic resin cage containing one of them is known (for example, see Patent Document 3).

  However, in recent years, rolling bearings used for supporting a motor of a hybrid vehicle, an electric vehicle, and a fuel cell vehicle or for supporting a gear directly connected to the motor are often used in a higher speed region that is not in the conventional transmission region. .

  When a rolling bearing incorporating a crown cage as shown in FIG. 6 is to be operated at a higher speed, stress concentrates on the pocket bottom due to the centrifugal force, and the maximum principal stress at the cage pocket bottom is the cage material. If the allowable strength is exceeded, the cage may be damaged.

  In addition, the pocket of the plastic cage is slightly larger than the ball diameter and has a clearance that allows for the delayed advancement of the ball caused by a certain degree of misalignment etc., so when the cage rotates at high speed In particular, the cage swings, and as a result, especially when rotating under light load and high speed conditions such as motor support bearings, it is significantly advantageous over the press cage, but skidding damage occurs and abnormal noise occurs. In the worst case, peeling or damage to the cage may occur.

Japanese Patent No. 2654814 Japanese Patent No. 2775983 JP 2000-297820 A

  The present invention has been made paying attention to the above-described problems, and causes problems such as skitting and cage breakage, which are a concern during high-speed rotation, without degrading the workability and incorporation of the cage. It is an object to provide a rolling bearing incorporating a non-crown type synthetic resin cage.

  In particular, rolling bearings incorporating a crown-shaped synthetic resin cage that does not cause problems such as skitting and cage breakage, which are a concern for motor supports of hybrid vehicles, electric vehicles, and fuel cell vehicles or gear support bearings directly connected to the motor. It is an issue to provide.

In order to solve the above problems, the rolling bearing according to the present invention is disposed between an inner ring having an inner ring raceway surface, an outer ring having an outer ring raceway surface, and a relative rotation between the inner ring raceway surface and the outer ring raceway surface. A plurality of rolling elements, and a cage that holds the rolling elements in a freely rollable manner, and the cage is constituted by an annular shape portion and a plurality of pillar portions extending in the axial direction from the annular shape portion. A synthetic resin crown type cage, wherein the cage is guided by both the inner ring outer diameter surface or the outer ring inner diameter surface and the rolling element,
An annular shaped portion of said retainer, the clearance between the inner ring outer diametric surface is 0.2 to 0.7 mm, Ri centroid annular shaped portion near the axial direction of said retainer, and The inner ring outer diameter surface or the outer ring inner diameter surface is located in a position overlapping in the radial direction .

  Furthermore, it is desirable that the cage is molded from PEEK resin containing 20 to 40% by weight of carbon fiber.

  The cage has an axial center of gravity in the ring-shaped part and is guided by both the rolling elements and the outer diameter surface of the inner ring, so the swing around the high-speed rotation is suppressed, effectively skidding, cage breakage, etc. Can prevent damage.

  In addition, by using a PEEK resin crown type resin cage reinforced with 20 to 40% by weight of carbon fiber, the tensile strength and fatigue strength are superior to those of conventional aliphatic polyamide resin cages, and the linear expansion coefficient is high. Because it is small (close to steel) and can maintain the clearance between the inner ring outer diameter surface and the cage over a wide temperature range, the cage can be stably guided by both the ball and the inner ring outer diameter surface. .

It is a figure which shows the semi-sectional view of the rolling bearing of one Embodiment of this invention. FIG. 2 is an external perspective view of a cage used in the rolling bearing shown in FIG. 1. The half sectional view of the conventional rolling bearing is shown. FIG. 4 is an external perspective view of an iron corrugated press cage used in the rolling bearing shown in FIG. 3. The half sectional view of the rolling bearing in other conventional structural examples is shown. FIG. 5 is an external perspective view of a synthetic resin crown-shaped cage used in the rolling bearing shown in FIG. 4.

Hereinafter, embodiments of the rolling bearing of the present invention will be described in detail with reference to FIGS. 1 and 2.
FIG. 1 is a half sectional view of a rolling bearing according to an embodiment of the present invention, and FIG. 2 is an external perspective view of a cage used in the rolling bearing shown in FIG.

  As shown in FIG. 1, a rolling bearing 1 according to an embodiment of the present invention includes an inner ring 2, an outer ring 3, balls 4 that are rolling elements, and a cage 5. The rolling bearing 1 is an open-type deep groove ball bearing, and is used, for example, for motor support or gear support directly connected to a motor in an automobile transmission, a hybrid car, an electric car, or a fuel cell car.

  The inner ring 2 is formed with an inner ring raceway surface 2a having a concave shape on the inner ring outer diameter surface 2b. Although the inner ring 2 may be used as a fixed ring, for example, the inner ring 2 is fitted on a rotating shaft of an automobile transmission or the like and functions as a rotating wheel.

  The outer ring 3 is formed with a concave outer ring raceway surface 3a at a position of the outer ring inner diameter surface 3b facing the inner ring raceway surface 2a. The outer ring 3 may be used as a rotating wheel for supporting the rotor. For example, the outer ring 3 is fitted in a housing such as an automobile transmission and functions as a fixed wheel.

  The balls 4 that are rolling elements are arranged between the inner ring raceway surface 2 a of the inner ring 2 and the outer ring raceway surface 3 a of the outer ring 3 so as to be freely rollable.

  The cage 5 is a crown-shaped cage formed of PEEK resin reinforced with 20 to 40% by weight of carbon fiber as a material, and a plurality of columns extending in the axial direction from the annular shape portion 7 and the annular shape portion 7. A plurality of pockets 6 are formed at a constant interval in the circumferential direction by the adjacent column portions 8 and 8. And the ball | bowl 4 which is a rolling element is hold | maintained in the pocket 6 of the holder | retainer 5 in the state which can roll freely.

  The retainer 5 inserts each ball 4 into a plurality of pockets 6 formed in the circumferential direction by elastically deforming and expanding the claws 8a provided at the end portions in the axial direction of the column portions 8. It is incorporated between the inner ring 2 and the outer ring 3 and is rotatably held in a form relatively guided by the balls 4.

  In the present invention, the groove position can be positioned at the center of the bearing width as in the conventional bearing. However, since the width dimension is required, the groove position is set in the axial direction in order to minimize the width dimension. A case where the offset is performed will be described.

  The conventional rolling bearing 10 shown in FIG. 5 has a track of a ball 13 in the center in the axial direction, whereas the rolling bearing 1 of one embodiment of the present invention shown in FIG. Four orbits are set. That is, in the rolling bearing 1 according to the embodiment of the present invention shown in FIG. 1, the length from the axial end on the pocket side of the cage 5 to the raceway of the balls 4 is the same length L1 as in the prior art. The length from one axial end of the side to the trajectory of the balls 4 is set to L2 which is longer than the conventional one.

  Similarly, the pocket bottom of the rolling bearing 1 according to the embodiment of the present invention shown in FIG. 1 with respect to the axial width W1 from the pocket bottom to the non-pocket side end face in the cage 14 of the conventional rolling bearing 10 shown in FIG. The axial width W2 from the end face to the non-pocket side is set to be longer than W1 by the amount that L2 is longer than L1. At this time, the length of W2 is such that the axial center of gravity of the cage 5 is not on the column portion 8 but on the annular portion side, preferably on the annular shape portion 7, with respect to the axial center position of the cage cross section. Is set. By making W2 longer, it is possible to increase the cage strength against the stress concentration at the bottom of the pocket generated by the action of centrifugal force, and to suppress the deformation of the cage during high-speed rotation.

  In the conventional rolling bearing 10 shown in FIG. 5, the gap dimension δ1 between the cage 14 and the inner ring outer diameter surface 11b is substantially the same as the gap dimension δ1 between the cage 14 and the outer ring inner diameter surface 12b. It is a dimension, and a sufficient clearance is set so as not to interfere with the inner ring and outer ring during rotation. On the other hand, in the rolling bearing 1 according to the embodiment of the present invention shown in FIG. 1, the clearance dimension between the cage 5 and the outer ring inner diameter surface 3b is δ1 as in the prior art, but the cage 5 and the inner ring outer diameter. The gap dimension δ2 between the surface 2b is narrower than δ1 and is set to 0.2 mm to 0.7 mm. Since the PEEK resin having a smaller linear expansion coefficient than that of the conventional aliphatic polyamide resin is used as the material of the cage 5, the gap dimension δ2 between the cage 5 and the inner ring outer diameter surface 2b over a wide temperature range. Therefore, the cage 5 can be stably guided by both the ball 4 and the inner ring outer diameter surface 2b (or the outer ring inner diameter surface 3a).

  By making W2 longer, the cage axial center of gravity is set on the annular portion 7, and by setting δ2 to 0.2 mm to 0.7 mm, the cage 5 is guided to the ball 4 as in the conventional case. At the same time, it is also guided to the inner ring outer diameter surface 2b. Therefore, with the ball guide alone, the run-out around the high-speed rotation is suppressed by guiding both the ball and the inner ring outer diameter surface as in this embodiment, effectively preventing skidding and breakage of the cage. it can.

  INDUSTRIAL APPLICABILITY The present invention can be suitably used as a rolling bearing, particularly a rolling bearing used for supporting a motor of a vehicle transmission, a hybrid vehicle, an electric vehicle, or a fuel cell vehicle, or a gear support directly connected to the motor.

DESCRIPTION OF SYMBOLS 1 Rolling bearing 2 Inner ring 2a Inner ring raceway surface 2b Inner ring outer diameter surface 3 Outer ring 3a Outer ring raceway surface 3b Outer ring inner diameter surface 4 Ball 5 Synthetic resin crown type cage 6 Pocket 7 Cage body 8 Column 8a Claw 10 Rolling bearing 11 Inner ring 11a Inner ring raceway surface 11b Inner ring outer diameter surface 12 Outer ring 12a Outer ring raceway surface 12b Outer ring inner diameter surface 13 Ball 14 Crown holder 15 made of synthetic resin 15 Pocket 16 Retainer body 17 Column 17a Claw 50 Rolling bearing 51 Inner ring 51a Inner ring raceway Surface 52 Outer ring 52a Outer ring raceway surface 53 Ball 54 Iron corrugated press retainer 57 Pocket 58 Recess 59 Recess 60 Metal member 61 Metal member 62 Rivet

Claims (3)

A rolling bearing for an automobile transmission,
An inner ring having an inner ring raceway surface;
An outer ring having an outer ring raceway surface;
A plurality of rolling elements arranged to be relatively rotatable between the inner ring raceway surface and the outer ring raceway surface;
A retainer that holds the rolling element so as to roll freely,
The retainer is a synthetic resin crown-shaped retainer composed of an annular shape portion and a plurality of pillar portions extending in the axial direction from the annular shape portion,
The cage is guided by both the inner ring outer diameter surface or the outer ring inner diameter surface and the rolling element,
The gap between the annular portion of the cage and the inner ring outer diameter surface is 0.2 mm to 0.7 mm,
Rolling, characterized in that the center of gravity in the axial direction of the cage Ri annular shape portion near and in the position overlapping the inner ring outer diametric surface or the outer ring inner diameter surface and radially.   The rolling bearing according to claim 1, wherein the cage is formed of PEEK resin containing 20 to 40% by weight of carbon fiber. The cage is guided by both the inner ring outer diameter surface and the rolling element,
A track of the rolling element is provided at a position biased in one axial direction;
The rolling bearing according to claim 1 , wherein an annular portion of the cage is disposed on a side having a larger axial width .

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