Resin holder for cylindrical roller bearings and cylindrical roller bearing

A resin cage for a cylindrical roller bearing used in a roller guide type comprising:

• a pair of annular portions;
• and
• a plurality of column portions which axially connect the pair of annular portions,
• wherein the resin cage forms a plurality of pocket portions which rotatably hold a plurality of cylindrical rollers respectively,
• wherein the column portion includes a roller holding portion at an axially intermediate portion,
• wherein each of both circumferential side surfaces of both axial end portions of the column portion located axially outer than the roller holding portion includes:
• a first flat surface which gradually shortens a circumferential length of the column portion from an outer circumferential surface toward an inner diameter side;
• and
• a second flat surface which gradually lengthens the circumferential length of the column portion from a connecting portion with the first flat surface toward the inner diameter side,
• wherein a pocket corner portion between the column portion and the annular portion includes:
• a first curved surface which has a first curvature radius and which connects the first flat surface to the annular portion;
• and
• a second curved surface which has a second curvature radius larger than the first curvature radius and which connects the second flat surface to the annular portion, and
• wherein in a state in which a revolution center of the cylindrical roller coincides with an axis center of the cage, the connecting portion between the first flat surface and the second flat surface and a connecting portion between the first curved surface and the second curved surface are located on an inner diameter side than a pitch circle diameter of the cylindrical rollers.