Railway car electric traction motor air cooling system

An air-cooling system for electric traction motors of a bogie of a motorized railway vehicle is shown which tends to reduce problems in drawing air through a cooling air channel to the traction motors and helps to reduce the problems encountered by the failure of a cooling fan for such electric traction motors. The air-cooling system is adapted for use with at least two air-cooled electric traction motors where each motor is coupled to an axle of a truck, the system comprising a common cooling air channel in communication with each traction motor and at least two intake channels communicating with the common cooling air channel, each intake channel including an air intake, a separately driven fan and valve means for preventing air from flowing out the intake upon failure of a fan to operate properly.

BACKGROUND OF THE INVENTION 
The present invention relates to a motorized railway vehicle having a truck 
with at least two air-cooled electric traction motors coupled to shafts of 
the truck, and more particularly, to an air-cooling system for such 
electric traction motors. 
In motorized railway vehicles, a number of trucks each having air-cooled 
electric traction motors are provided to propel the vehicle. As a rule, 
the axle of each wheel pair of a truck is coupled to an electric drive 
traction motor by means of a gear reduction set. In order to obtain high 
power within a limited motor volume, the electric traction motors are 
usually fan-cooled and each is provided with a cooling air fan and a 
cooling air channel for providing cooling air to the fan. However, the 
available space for cooling air channels in a railway vehicle is limited 
and drawing air through these channels may involve various problems. If 
the motors are not cooled by proper operation of the air-cooling system, 
rapid overheating of the motors occurs and ultimately, cause damage to the 
motors. Therefore, the electric traction motors should not be utilized if 
the cooling system, particularly the cooling fan for the cooling system, 
is inoperative. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, these difficulties in drawing in 
air through the cooling air channels and the problems occasioned in the 
event of failure of a cooling fan are reduced, or even eliminated, by 
connecting at least two electric traction motors of a truck to a common 
cooling air channel and by supplying cooling air to the cooling air 
channel with two parallel-working and separately driven fans, each located 
in a separate intake channel containing a cooling air intake. Located 
between the common cooling air channel and the separate cooling air intake 
channels containing the fans are valve means which help prevent the flow 
of cooling air from the common cooling air channel out through the cooling 
air intake when the particular fan is not operating. The valve means are 
suitably constructed as automatically acting non-return valves of the 
clack type having clacks or lips of rubber, plastic or thin sheet metal 
which are held in an open position during the flow of cooling air caused 
by the fan and automatically return to a closed position when air flow 
ceases due to the stoppage of a fan. 
The cooling air intakes of the intake channels are preferably located at an 
upper portion of the railway vehicle where the air to be drawn into the 
intake is less likely to be contaminated by dust or other foreign matter. 
In addition, the cooling air intakes of the intake channels are provided 
with suitable filters and water separators so as to help prevent harmful 
material such as dust and the like from accompanying the cooling air to 
the traction motors. 
By using the air cooling system of the present invention in a motorized 
railway vehicle, the drawing of air through the cooling channels is 
facilitated and therefore enables the production of a restricted, although 
considerable, power from the electric traction motors. In addition, in the 
situation where a fan blade or a fan motor of a fan has become damaged and 
therefore inoperative, the invention still enables a motorized railway 
vehicle to operate at a limited speed since moe than 50% of the normal 
power can still be obtained. Therefore, upon failure of a fan, a 
speed-limiting power shortage only occurs when maximum power is needed 
such as upon acceleration and traveling over track sections with a sharp 
incline. By operating the cooling-air fans in a parallel manner, the 
reliability of operation of the motorized railway vehicle is increased and 
the expensive and irritating consequences for railway operation due to 
damage to a small but important component such as a fan are reduced. 
The present invention will be described in more detail with reference to 
the accompanying drawing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to the accompanying drawings wherein like numerals refer to like 
structural elements, a motorized railway vehicle 1 is shown in FIG. 3 to 
be supported by two truck which each have electric traction drive motors 
supplied with cooling air by a cooling air supply system in accordance 
with the present invention. As shown in larger scale in FIG. 1, each truck 
comprises two pairs of wheels 2, frame 17, two electric traction drive 
motors 3 and a power transmission 4 between each drive motor and drive 
axle 5 of each wheel pair or wheel set. The drive motors 3 are cooled by 
air provided by a cooling air system of the present invention. Cooling air 
comes into the system at the upper portion of end wall 6 of the body of 
vehicle 1 through air intakes 7 which are provided with water separators 
and filters (not shown) for removing solid contaminants from the air. The 
air intakes 7 are located at the upper portion of vertical air intake 
channels 8. Two parallel-working and separately driven cooling air fans 9 
are connected on their suction sides to the vertical intake channels 8 and 
on their pressure sides to horizontal common cooling air channel 10 
located under the body of vehicle 1. As best seen in FIG. 2 positioned 
between each fan 9 and the common cooling air channel 10 is a non-return 
valve 11 which helps prevent the flow of air from common cooling air 
channel 10 back through a fan in the event of failure of the fan. 
On the bottom surface 12 of the common cooling air channel 10 are openings 
13, each having a flange 14, just above the cooling air intake 15 of each 
of the drive motors 3. Between the flange 14 and cooling air intake 15 of 
each of the drive motors 3 is a bellows (not shown) which absorbs movement 
between the bogie and the body of the vehicle 1. 
The arrows shown in FIGS. 1 and 3 indicate the direction of flow of the 
cooling air during the operation of the cooling air system of the present 
invention. Air flows through each intake 7 and down through the respective 
intake channels 8 and thence into the common cooling-air channel 10. From 
the common cooling-air channel 10, the air flows through openings 13 and 
down through flange 14 into the intake 15 of each drive motor 3 whereby 
the motor is cooled and then the air is exhausted through exhaust parts as 
indicated by arrows 16. 
While the present invention has been described with reference to a 
particular embodiment thereof, it will be understood that numerous 
modifications may be made by those skilled in the art without actually 
departing from the spirit and scope of the invention as defined in the 
appended claims.