A seal ring-equipped ball bearing for assembly in a rotation-support section of an automobile transmission, comprising:
- an outer ring that has an outer-ring raceway around an inner-circumferential surface, and that does not rotate during use;
- an inner ring that has an inner-ring raceway around an outer-circumferential surface, and that rotates during use;
- plural balls that are arranged between the outer-ring raceway and the inner-ring raceway so as to roll freely;
- a retainer holding the plural balls so as to roll freely;
- and
- a seal ring that is fastened around the inner-circumferential surface on an end section in an axial direction of the outer ring, and covers an opening on an end section in the axial direction of a ring-shaped internal space that exists between the inner-circumferential surface of the outer ring and the outer-circumferential surface of the inner ring where the balls are located;
- wherein a load-bearing surface is provided on an end surface in the axial direction of the inner ring, to contact a member that is arranged adjacent in the axial direction when the seal ring-equipped ball bearing is assembled in the rotation-support section, and to support a load in the axial direction that acts from the member;
- wherein the seal ring comprises:
- an annular shaped metal insert;
- and
- an elastic member that is reinforced by the metal insert, and has a seal lip that is formed by protruding an entire inner-circumferential edge section of the elastic member further inward in a radial direction than the metal insert, and that is able to elastically deform in at least the radial direction;
- and
- wherein the seal lip comprises:
- an outer-diameter-side inclined section that is inclined inward in the radial direction and in a direction toward a center side in the axial direction of the seal ring-equipped ball bearing going away from an inner-circumferential edge of the metal insert;
- and
- an inner-diameter-side inclined section that is inclined inward in the radial direction and in a direction toward an outside in the axial direction of the seal ring-equipped ball bearing going away from the outer-diameter-side inclined section;
- and
- a continuous section that makes a small-diameter side end section of the outer-diameter-side inclined section and a large-diameter-side end section of the inner-diameter-side inclined section continuous;
- wherein a portion that is bounded by an inner-circumferential surface of the outer-diameter-side inclined section, an outer-circumferential surface of the inner-diameter-side inclined section, and an axial side surface in the axial direction of the continuous section is a groove section that has a wedge-shape cross section;
- wherein a surface on an opposite side in the axial direction from the groove section is taken to be an inside-continuous surface;
- and
- wherein an inner-circumferential edge section of the inner-diameter-side inclined section, which is a tip-end edge of the seal lip, comes in sliding contact entirely around the outer-circumferential surface of the end section in the axial direction of the inner ring, and in a cross-sectional shape on a virtual plane that includes the center axis of the seal ring, an angle between the center axis and an extended line of the inside-continuous surface is 104° or greater but no greater than 150°;
- a length dimension L of a fixed-thickness portion of the continuous section where a thickness dimension is fixed is regulated to be within the range of one to two times a thickness dimension H of the fixed-thickness portion;
- the thickness dimension H of the fixed-thickness portion is 200 μm to 400 μm;
- and
- an interference S of the seal lip is 3 or less times the thickness dimension H of the fixed-thickness portion.