In the motor including the coils having the concentrated-winding structure, in a case where the number of coils is larger than the number of field magnetic poles, a blade angle in a cross section perpendicular to a rotation axis of the motor becomes smaller than a magnet angle. As a result, a magnet magnetic flux is insufficiently picked up, and there is a problem that it is difficult to effectively utilize the magnetic flux. In addition, in a case where a coil having a straddling winding structure in which an electric wire is wound so as to straddle a plurality of teeth is adopted, there is a problem that it is difficult to increase torque because a coil end bulges so that winding resistance increases.

One object of the present disclosure is to provide a brush motor that has been created in light of the above problems and is capable of achieving downsizing and high torque with a simple configuration. Note that the present disclosure is not limited to this object, and it is also possible to position, as another object of the present disclosure, achieving functions and effects that are derived from each configuration illustrated in “DETAILED DESCRIPTION” to be described later, the functions and effects being hardly obtained by conventional techniques.

A brush motor according to an embodiment of the present disclosure includes: a rotor core provided in a rotor; s teeth provided in the rotor core; s concentrated-winding coils with electric wires being respectively wound around the teeth; a commutator provided on the rotor in a relatively non-rotatable manner; c commutator pieces provided in the commutator and connected to the coils; p pairs of magnet magnetic poles provided on a stator and arranged to face the teeth; and a brush that is brought into sliding contact with the commutator pieces to supply a current to the coils, in which the following inequality A and inequality B hold.