Railcar steering bogie including brake unit
A railcar steering bogie includes a bogie frame, a wheelset, an axle box suspension, a steering mechanism configured to steer the wheelset, a brake unit, and a brake unit support link. The brake unit includes: a main body frame; a brake shoe supported by the main body frame and pressed against a wheel tread of the wheel during braking. The brake unit support link couples the axle box suspension and the brake unit and transmits displacement of the axle box in a car longitudinal direction to the brake unit at least during steering performed by the steering mechanism. The brake unit support link restricts the brake unit from being displaced outward in a car width direction by a predetermined distance or more during the braking. At least one of a side surface of the brake unit support link and a side surface of the brake unit includes a sliding surface.
1. A railcar steering bogie comprising:
a bogie frame;
a wheelset including an axle and a pair of wheels;
an axle box suspension coupling an axle box and the bogie frame, the axle box accommodating a bearing supporting the axle;
a steering mechanism configured to steer the wheelset;
a brake unit including
a main body frame including an upper portion rotatably attached to the bogie frame and
a brake shoe supported by the main body frame and pressed against a wheel tread of the wheel during braking; and
a brake unit support link coupling the axle box suspension and the brake unit and configured to transmit displacement of the axle box in a car longitudinal direction to the brake unit at least during steering performed by the steering mechanism,
the brake unit support link being outward of the wheel in a car width direction,
the brake unit support link restricting the brake unit from being displaced outward in the car width direction by a predetermined distance or more during the braking,
at least one of a side surface of the brake unit support link and a side surface of the brake unit including a sliding surface.
2. The railcar steering bogie according to claim 1 , wherein the other of the side surface of the brake unit support link and the side surface of the brake unit includes a protruding portion configured to slide on the sliding surface.
3. The railcar steering bogie according to claim 1 , wherein:
the brake unit support link extends in the car longitudinal direction outward of the wheel in the car width direction and is opposed to the brake unit from outward of the brake unit in the car width direction; and
the sliding surface is at an inside surface of the brake unit support link in the car width direction.
4. The railcar steering bogie according to claim 3 , wherein:
the axle box suspension includes an axle beam coupling the axle box and the bogie frame and extending in the car longitudinal direction; and
the brake unit support link is arranged at a position deviated from the axle beam in a vertical direction.
5. The railcar steering bogie according to claim 1 , wherein the sliding surface has a circular-arc shape that is convex in the car width direction.
6. The railcar steering bogie according to claim 1 , wherein one end portion of the brake unit support link is coupled to the axle box suspension through a spherical bearing, and the other end portion of the brake unit support link is coupled to the main body frame through a spherical bearing.
7. The railcar steering bogie according to claim 6 , wherein:
each of the spherical bearings includes an inner tube, an outer tube, and an elastic body sandwiched between the inner tube and the outer tube; and
the elastic body is made of self-lubricating rubber.