Disk drive base unit with communicating groove extending outside outer circumferential portion of connector

A base unit for use in a disk drive apparatus including a case an interior of which is filled with helium, hydrogen, a gas mixture of helium and hydrogen, or a gas mixture of air and any one of helium, hydrogen, and the gas mixture of helium and hydrogen, the base unit comprising:

• a base member arranged to support a motor;
• and
• a connector electrically connected to a head included in an access portion arranged to perform at least one of reading and writing of information from or to a disk supported by a rotating portion of the motor;
• wherein
• the base member includes:
• a bottom plate portion arranged to extend perpendicularly to a central axis of the motor;
• a window portion arranged to pass through the bottom plate portion in an axial direction;
• and
• a first groove defined in an upper surface or a lower surface of the bottom plate portion around the window portion;
• the connector includes:
• a board portion arranged on the upper surface or the lower surface of the bottom plate portion, and arranged to cover the window portion and at least a portion of the first groove;
• and
• an electrode terminal arranged on the board portion;
• the electrode terminal is arranged on an upper or lower side of the window portion;
• an adhesive layer is arranged between the bottom plate portion and a surface of the board portion facing the bottom plate portion;
• the adhesive layer is arranged to define a continuous closed loop around the window portion;
• a portion of the adhesive layer is held in at least a portion of the first groove;
• and
• the first groove includes at least one communicating groove arranged to extend up to a position outside of an outer circumferential portion of the connector.