Plain bearing and pump

A pump for transferring a fluid by pressure, comprising:

• a housing;
• a shaft provided in the housing;
• an impeller that rotates with respect to the housing to transfer a fluid by pressure inside the housing;
• an annular plain bearing that rotatably supports the impeller with respect to the housing;
• and
• an annular restrictor that is fixed to the housing and restricts movement of the plain bearing in an axial direction, wherein
• either on one of an end face of the plain bearing facing the restrictor and an end face of the restrictor facing the plain bearing, a lubrication groove communicating with a radially inner side and a radially outer side of the plain bearing to supply the fluid onto the end face for lubrication, and a dynamic pressure generating groove that introduces a fluid flow created by rotation of the impeller to generate a dynamic pressure, are provided,
• the lubrication groove is formed linearly in a radial direction, and
• the dynamic pressure generating groove is formed to extend circumferentially from the lubrication groove.