BALL BEARING

PROBLEM TO BE SOLVED: To suppress degradation of acoustic performance in a ball bearing.SOLUTION: A ball bearing includes an inner ring having an inner raceway surface on an outer periphery, an outer ring 3 having an outer raceway surface 31 on an inner periphery, a plurality of balls disposed between the inner raceway surface and the outer raceway surface 31, and a cage for holding the plurality of balls at intervals in the circumferential direction. A recessed groove 41 continued in the circumferential direction and a projection 42 continued in the circumferential direction are alternately arranged on at least one raceway surface of the inner raceway surface and the outer raceway surface 31. A width of the recessed groove 41 is larger than a depth of the recessed groove 41.SELECTED DRAWING: Figure 1 【課題】玉軸受において、音響性能の低下を抑制する。【解決手段】玉軸受は、外周に内軌道面が形成されている内輪と、内周に外軌道面３１が形成されている外輪３と、内軌道面と外軌道面３１との間に介在している複数の玉と、複数の玉を周方向に間隔をあけて保持する保持器とを備えている。内軌道面及び外軌道面３１の内の少なくとも一方の軌道面に、周方向に連続した凹溝４１と周方向に連続した凸条４２とが交互に並んで設けられている。凹溝４１の幅は凹溝４１の深さよりも大きい。【選択図】 図１