Rolling bearing

1. A rolling bearing used in a preloaded state comprising:

an inner ring;

an outer ring;

a seal fixing groove provided at either the inner ring or the outer ring;

a seal contact groove provided at either the inner ring or the outer ring on a side where the seal fixing groove has not been provided; and

a sealing member with two ends,

wherein one end of the sealing member is fitted into the seal fixing groove and the other end of the sealing member is configured not to contact the seal contact groove in a non-preloaded state but to contact the seal contact groove in an axial direction in a preloaded state; and a central line average roughness Ra of a contact surface of the seal contact groove to which the sealing member contacts is Ra≦0.6 μm.

2. The rolling bearing according to claim 1 , wherein the sealing member is an approximately annular member in which a metal core is covered by an elastic member,

the sealing member comprises: a peripheral wall part, which is an elastic body that protrudes from a peripheral portion of the metal core at the seal contact groove side toward an axially inside direction; and a lip part including a first lip which protrudes toward an axially inside direction allowing the first lip to contact the seal contact groove in an axial direction and a second lip which protrudes toward an axially outside direction not allowing the second lip to contact the seal contact groove, and

the peripheral wall part and the lip part are connected to each other via a neck part whose thickness is smaller than that of the peripheral wall part and the lip part.

3. The rolling bearing according to claim 1 , wherein the rolling bearing is provided for supporting a shaft member of a motor, and the sealing member is placed at least on an end surface side of the rolling bearing which faces an outside of the motor.

4. The rolling bearing according to claim 1 , wherein at least the contact surface is covered with a solid lubricating coating.

5. The rolling bearing according to claim 4 , wherein the solid lubricating coating is a diamond like carbon coating.

6. A rolling bearing used in a preloaded state comprising:

an inner ring;

an outer ring;

a seal contact groove provided at either the inner ring or the outer ring; and

a sealing member with two ends,

wherein one of the ends of the sealing member contacts the seal contact groove in an axial direction only when a preload is applied; and a central line average roughness Ra of a contact surface of the seal contact groove to which the sealing member contacts is Ra≦0.6 μm.

7. The rolling bearing according to claim 6 , wherein the sealing member is an approximately annular member in which a metal core is covered by an elastic member,

the sealing member comprises:

a peripheral wall part, which is an elastic body that protrudes from a peripheral portion of the metal core at the seal contact groove side toward an axially inside direction; and

a lip part including a first lip protruding toward an axially inside direction which contacts the seal contact groove in an axial direction when the preload is applied, and a second lip protruding toward an axially outside direction which does not contact the seal contact groove even when the preload is applied, and

the peripheral wall part and the lip part are connected to each other via a neck part whose thickness is smaller than that of the peripheral wall part and the lip part.

8. The rolling bearing according to claim 6 for supporting a shaft member of a motor wherein the sealing member is placed at least on a side of the rolling bearing which faces an outside of the motor.

9. The rolling bearing according to claim 6 , wherein at least the contact surface is covered with a solid lubricating coating.

10. The rolling bearing according to claim 9 , wherein the solid lubricating coating is a diamond like carbon coating.