Railcar air conditioning duct
A railcar air conditioning duct according to one aspect which guides air fed from an air conditioner mounted on a railcar. The railcar includes: a duct wall forming an air flow passage which guides air in a car longitudinal direction; and a plurality of through holes lined up in the car longitudinal direction, the through holes being open at the duct wall as air outlet ports through which the air in the air flow passage is blown from the air flow passage toward a passenger room. A ratio of an opening area of one of the through holes to an area of one of a plurality of partial regions formed by dividing, in the car longitudinal direction, an inner surface of a lower wall portion such that in plan view, the regions contain the respective through holes falls within a range of 2.0% or more and 7.5% or less.
1. A railcar air conditioning duct which guides air fed from an air conditioner mounted on a railcar,
the railcar air conditioning duct comprising:
a duct wall forming an air flow passage which guides the air, fed from the air conditioner, in a car longitudinal direction; and
a plurality of through holes lined up in the car longitudinal direction, the through holes being open at a lower wall portion of the duct wall as air outlet ports through which the air in the air flow passage is blown from the air flow passage toward a passenger room, wherein:
a ratio of an opening area of one of the through holes to an area of one of a plurality of partial regions formed by dividing, in the car longitudinal direction, an inner surface of the lower wall portion such that in plan view, the partial regions contain the respective through holes falls within a range of 2.0% or more and 7.5% or less;
air receiving plates which are located in the air flow passage and receive the air flowing through the air flow passage in the car longitudinal direction project upward at opening edge portions of the respective through holes so as to be located at a far side from the air conditioner, and a top edge of each of the air receiving plates is a free edge;
an outer surface of the lower wall portion of the duct wall faces the passenger room in the railcar;
a groove extending in the car longitudinal direction is formed at an inner surface opposite to the outer surface of the lower wall portion;
the groove includes:
a pair of side walls opposed to each other in a car width direction, and
a bottom wall located between the inner surface and the outer surface of the lower wall portion in an upper-lower direction and connecting lower end portions of the pair of side walls;
and
the plurality of through holes are provided at the bottom wall of the groove.
2. The railcar air conditioning duct according to claim 1 , further comprising an air feed port through which the air is fed from the air conditioner, wherein
the air flow passage has a chamber-less structure which faces both the air feed port and the through holes.
3. The railcar air conditioning duct according to claim 1 , wherein a length of each of the through holes in the car longitudinal direction falls within a range of 0.25 time or more and 2.5 times or less a length of the through hole in a car width direction.
4. The railcar air conditioning duct according to claim 1 , wherein:
the opening areas of the plurality of through holes are equal to each other; and
the plurality of through holes are lined up in the car longitudinal direction at regular intervals.
5. The railcar air conditioning duct according to claim 1 , wherein:
a return duct which extends in an upper-lower direction and takes the air from the passenger room into the air conditioner is provided at a car width direction middle of the railcar;
the air flow passage includes an intake port vicinity region extending in the car longitudinal direction at a position away from the return duct in a car width direction; and
the through holes are arranged so as to overlap the intake port vicinity region in plan view.
6. The railcar air conditioning duct according to claim 5 , wherein the through holes are located at an opposite side of the return duct within a range which overlaps the intake port vicinity region in plan view.
7. The railcar air conditioning duct according to claim 1 , further comprising horizontal plate portions each located between two of the through holes which are adjacent to each other in the car longitudinal direction, wherein
the air receiving plates project at end portions of the respective horizontal plate portions so as to be located at a near side from the air conditioner.
8. A railcar air conditioning duct which guides air fed from an air conditioner mounted on a railcar,
the railcar air conditioning duct comprising:
a duct wall forming an air flow passage which guides the air, fed from the air conditioner, in a car longitudinal direction; and
a plurality of through holes lined up in the car longitudinal direction, the through holes being open at the duct wall as air outlet ports through which the air in the air flow passage is blown from the air flow passage toward a passenger room, wherein:
a ratio of an opening area of one of the through holes to a total of opening areas of all the through holes that are open at the duct wall falls within a range of 0.05% or more and 0.65% or less,
air receiving plates which are located in the air flow passage and receive the air flowing through the air flow passage in the car longitudinal direction project upward at opening edge portions of the respective through holes so as to be located at a far side from the air conditioner, and a top edge of each of the air receiving plates is a free edge;
an outer surface of the lower wall portion of the duct wall faces the passenger room in the railcar;
a groove extending in the car longitudinal direction is formed at an inner surface opposite to the outer surface of the lower wall portion;
the groove includes:
a pair of side walls opposed to each other in a car width direction, and
a bottom wall located between the inner surface and the outer surface of the lower wall portion in an upper-lower direction and connecting lower end portions of the pair of side walls; and
the plurality of through holes are provided at the bottom wall of the groove.
9. The railcar air conditioning duct according to claim 8 , further comprising an air feed port through which the air is fed from the air conditioner, wherein
the air flow passage has a chamber-less structure which faces both the air feed port and the through holes.
10. The railcar air conditioning duct according to claim 8 , wherein a length of each of the through holes in the car longitudinal direction falls within a range of 0.25 time or more and 2.5 times or less a length of the through hole in a car width direction.
11. The railcar air conditioning duct according to claim 8 , wherein:
the opening areas of the plurality of through holes are equal to each other; and
the plurality of through holes are lined up in the car longitudinal direction at regular intervals.
12. The railcar air conditioning duct according to claim 8 , wherein:
a return duct which extends in an upper-lower direction and takes the air from the passenger room into the air conditioner is provided at a car width direction middle of the railcar;
the air flow passage includes an intake port vicinity region extending in the car longitudinal direction at a position away from the return duct in a car width direction; and
the through holes are arranged so as to overlap the intake port vicinity region in plan view.
13. The railcar air conditioning duct according to claim 12 , wherein the through holes are located at an opposite side of the return duct within a range which overlaps the intake port vicinity region in plan view.
14. The railcar air conditioning duct according to claim 8 , further comprising horizontal plate portions each located between two of the through holes which are adjacent to each other in the car longitudinal direction, wherein
the air receiving plates project at end portions of the respective horizontal plate portions so as to be located at a near side from the air conditioner.