axle box

from The Century Dictionary.

• noun The box which contains the bearings for the spindle of an axle, or the journal of an axle, as of a carriage-wheel, a railroad-car wheel, etc.; the bushing or metal lining of the hub which forms the rotatory bearing of the axle of a vehicle.

from the GNU version of the Collaborative International Dictionary of English.

• A bushing in the hub of a wheel, through which the axle passes.
• The journal box of a rotating axle, especially a railway axle.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A bushing in the hub of a wheel, through which the axle passes.
• noun The journal box of a rotating axle, especially a railway axle.