Guide roller for slide door of vehicle

A guide roller for a slide door of a vehicle, wherein the guide roller is configured to be rotatably supported by a support member attached to the slide door of the vehicle and to roll and move along a rail on a vehicle body,

• wherein the guide roller comprising:
• an annular metal inner ring to be attached to the support member;
• a retainer holding a bearing;
• an annular metal outer ring rotatably held by the inner ring via the retainer, the outer ring having an outer circumferential surface;
• and
• a sliding layer coating on the outer circumferential surface of the outer ring, the sliding layer comprising a synthetic resin, and the sliding layer having a thickness and an outer circumferential surface serving as a sliding surface,
• wherein, when the sliding layer is sectionalized into a sliding surface side area, an intermediate area and an interface side area,
• the sliding surface side area being defined as an area extending from the sliding surface of the sliding layer toward an interface between the sliding layer and the outer ring and having a thickness of 25% of the sliding layer thickness;
• the interface side area being defined as an area extending from the interface toward the sliding surface and having a thickness of 25% of the sliding layer thickness;
• and
• the intermediate area is defined as an area between the sliding surface side area and the interface side area,
• (a) the synthetic resin in the sliding surface side area has a degree of crystallization X1, the synthetic resin in the intermediate area has a degree of crystallization X2, and the synthetic resin in the interface side area has a degree of crystallization X3 wherein
• X2−X1 is less than 5%, and
• X2−X3 is less than 5%, and
• (b) the synthetic resin in the sliding surface side area has a nanoindenter hardness Y1, the synthetic resin in the intermediate area has a nanoindenter hardness Y2, and the synthetic resin in the interface side area has a nanoindenter harness Y3 wherein
• Y2 is not less than 115% of Y1, and
• Y2 is not less than 115% of Y3.