Various embodiments include a brush holder apparatus. In one embodiment, a brush holder apparatus for receiving a brush includes: a first support member; a box member affixed to the first support member; and a cam member operably connected to the first support member, the cam member configured to retain the brush against an inner surface of the box member.

A fluid delivery module includes a housing with a housing interior volume, the housing defining a first brush compartment and a second brush compartment within the housing interior volume; an inlet which introduces fluid into the housing interior volume; an outlet which discharges fluid from the housing interior volume; a fluid pump within the housing interior volume and having a pump section and a motor assembly which receives electric power through a first carbon brush and a second carbon brush such that the first carbon brush is received within a first carbon brush holder of the motor assembly and the second carbon brush is received within a second carbon brush holder of the motor assembly; and a filter within the housing interior volume which circumferentially surrounds the fluid pump. The first brush compartment encloses the first carbon brush holder and the second brush compartment encloses the second carbon brush holder.

A positive connection plate of a DC motor includes a fitting groove to enable assembling a specific brush holder thereto. The specific brush holder includes a convex part that fits in the fitting groove and a stepped surface having a step at a radially outer side of the convex part, and located at the opposite-core side of its armature from a core-side end surface of the convex part. A space existing in an axial stepped area which is located at the core side from the stepped surface and in which the step is formed is a stepped space. A drawing member is drawn from a position which circumferentially overlaps with the specific brush holder to the outside of a motor case, and is disposed so as to overlap with the stepped space in the axial direction.

A power tool is less likely to generate noise. A power tool includes a housing, a field fixed to the housing and including a field coil, an armature rotatable relative to the field and including a commutator, two brushes that come in contact with the commutator, and a brush holder unit holding the two brushes. The brush holder unit includes two contact rails electrically connectable to the field coil, two first terminals that each come in contact with either of the two contact rails, two second terminals each electrically connectable to a corresponding brush of the two brushes, and a choke coil located between at least one of the two first terminals and at least one of the two second terminals.