Axle box suspension of railcar bogie
An axle box suspension of a railcar bogie is configured to couple an axle box, accommodating a bearing supporting an axle, to a bogie frame and includes: an axle beam including an axle beam main body portion and an axle beam end portion, the axle beam main body portion extending from the axle box in a car longitudinal direction, the axle beam end portion being provided at a tip end of the axle beam main body portion and including a tubular portion that is open at both car width direction sides; a core rod inserted into an internal space of the tubular portion in a car width direction; an elastic bushing interposed between the tubular portion and the core rod; and a receiving seat provided at the bogie frame, both end portions of the core rod being connected to the receiving seat, the tubular portion being divided into a first semi-tubular portion and a second semi-tubular portion, the first semi-tubular portion being formed integrally with the axle beam main body portion, the second semi-tubular portion being stacked on the first semi-tubular portion in an upward/downward direction.
1. An axle box suspension of a railcar bogie, the axle box suspension being configured to couple an axle box to a bogie frame, the axle box accommodating a bearing supporting an axle,
the axle box suspension comprising:
an axle beam including an axle beam main body portion and an axle beam end portion, the axle beam main body portion extending from the axle box in a car longitudinal direction, the axle beam end portion being provided at a tip end of the axle beam main body portion and including a tubular portion that is open at both car width direction sides;
a core rod inserted into an internal space of the tubular portion in a car width direction;
an elastic bushing interposed between the tubular portion and the core rod; and
a receiving seat provided at the bogie frame, both end portions of the core rod being connected to the receiving seat,
the tubular portion being divided into a first semi-tubular portion and a second semi-tubular portion, the first semi-tubular portion being formed integrally with the axle beam main body portion, the second semi-tubular portion being stacked on the first semi-tubular portion in an upward/downward direction, and
wherein the second semi-tubular portion includes:
a main opposing surface opposing the first semi-tubular portion in the upward/downward direction, and
a sub opposing surface opposing at least one of the first semi-tubular portion and the axle beam main body portion in the car longitudinal direction.
2. The axle box suspension according to claim 1 , wherein the sub opposing surface includes:
a first sub opposing surface configured to restrict displacement of the second semi-tubular portion relative to the first semi-tubular portion in one direction along the car longitudinal direction; and
a second sub opposing surface configured to restrict displacement of the second semi-tubular portion relative to the first semi-tubular portion in the other direction along the car longitudinal direction.
3. The axle box suspension according to claim 1 , wherein when viewed from the car width direction, a circumferential length of a semi-cylindrical inner surface of the first semi-tubular portion is longer than a circumferential length of a semi-cylindrical inner surface of the second semi-tubular portion.
4. The axle box suspension according to claim 3 , further comprising a fastening member inserted into the first semi-tubular portion and the second semi-tubular portion in the upward/downward direction to fix the second semi-tubular portion to the first semi-tubular portion, wherein
when viewed from the car width direction, the first semi-tubular portion projects toward the second semi-tubular portion beyond a virtual line extending through a center of the tubular portion and perpendicular to a direction in which the fastening member is inserted.
5. The axle box suspension according to claim 2 , wherein when viewed from the car width direction, a circumferential length of a semi-cylindrical inner surface of the first semi-tubular portion is longer than a circumferential length of a semi-cylindrical inner surface of the second semi-tubular portion.
6. The axle box suspension according to claim 5 , further comprising a fastening member inserted into the first semi-tubular portion and the second semi-tubular portion in the upward/downward direction to fix the second semi-tubular portion to the first semi-tubular portion, wherein
when viewed from the car width direction, the first semi-tubular portion projects toward the second semi-tubular portion beyond a virtual line extending through a center of the tubular portion and perpendicular to a direction in which the fastening member is inserted.