Rolling bearing and spindle apparatus for machine tool

A rolling bearing, comprising:

• an inner ring;
• an outer ring;
• a plurality of rolling elements rotatably disposed between the inner ring and the outer ring;
• and
• a retainer for retaining the rolling elements, the retainer being made of a resin material and formed by an injection-molding, the retainer having a recess axially extending on an outer periphery thereof, wherein said recess does not extend around an entire circumference of the retainer, and
• wherein the recess has a parting line formed at the time of injection-molding.

A rolling bearing, comprising:

• an inner ring having an outer surface;
• an outer ring having an inner surface;
• a plurality of rolling elements rotatably disposed between the inner ring and the outer ring;
• and
• a retainer for retaining the rolling elements, the retainer being made of a resin material, the retainer including a guided surface that is guided by the inner surface of the outer ring or the outer surface of the inner ring and a pocket holding the rolling element,
• wherein a guide clearance between the inner surface of the outer ring or the outer surface of the inner ring and the guided surface of the retainer is set to 0.05-0.4% of a diameter of the guided surface of the retainer, and
• wherein a clearance between the pocket of the retainer and the rolling element is set to 0.8-1.8% of the guide clearance.

A rolling bearing comprising:

• an inner ring having an outer surface;
• an outer ring having an inner surface;
• a plurality of rolling elements rotatably disposed between the inner ring and the outer ring;
• and,
• a retainer for retaining the rolling elements, the retainer being made of a resin material, the retainer being positioned with respect to the inner surface of the outer ring or the outer surface of the inner ring, the retainer including a pair of annular portions axially arranged in parallel and a columnar portion coupling the annular portions,
• wherein the following expression is obtained:
• AI=LH3/dm2≧0.025 mm2
• in which H is a radial length of a section of the annular portion, L is an axial length of the same, and dm is PCD of the rolling element, and
• wherein the retainer further includes a guided surface that is guided by the inner surface of the outer ring or the outer surface of the inner ring, and a pocket holding the rolling element,
• wherein a guide clearance between the inner surface of the outer ring or the outer surface of the inner ring and the guided surface of the retainer is set to 0.05-0.4% of a diameter of the guided surface of the retainer;
• and
• wherein a clearance between the pocket of the retainer and the rolling element is set to 0.8-1.8% of the guide clearance.

A rolling bearing comprising:

• an inner ring having an outer surface;
• an outer ring having an inner surface;
• a plurality of rolling elements rotatably disposed between the inner ring and the outer ring;
• and
• a retainer for retaining the rolling elements, the retainer being made of a synthetic resin material, the retainer including a guided surface that is guided by the inner surface of the outer ring,
• wherein the guided surface has two or more recesses and the number of the recesses is the same as the number of rolling elements, wherein a depth of the recesses is 0.3 mm or more,
• wherein the synthetic resin material comprises glass fiber in the amount of 10-40 wt %, carbon fiber in the amount of 10-30 wt %, or aramid fiber in the amount of 10-30 wt %,
• wherein the retainer further includes a pocket holding the rolling element,
• wherein a guide clearance between the inner surface of the outer ring or the outer surface of the inner ring and the guided surface of the retainer is set to 0.05-0.4% of a diameter of the guided surface of the retainer;
• and
• wherein a clearance between the pocket of the retainer and the rolling element is set to 0.8-1.8% of the guide clearance.

Rolling bearing comprising:

• an inner ring having an outer surface;
• an outer ring having an inner surface;
• a plurality of rolling elements rotatably disposed between the inner ring and the outer ring;
• and
• a retainer for retaining the rolling elements, the retainer being made of a synthetic resin material, the retainer including a guided surface that is guided by the inner surface of the outer ring,
• wherein the guided surface has two or more recesses and the number of the recesses is the same as the number of rolling elements, wherein a depth of the recesses is 0.3 mm or more,
• wherein the synthetic resin material comprises glass fiber in the amount of 10-40 wt %, carbon fiber in the amount of 10-30 wt %, or aramid fiber in the amount of 10-30 wt %, and
• further wherein the retainer is formed by an injection-molding, and the recess has a parting line formed at the time of injection-molding.