LOCOMOTIVE AIR COMPRESSOR WITH AN ELECTRIC MOTOR SUPPORTED BY AN EXTERNAL BEARING

COMPRESSEUR D'AIR DE LOCOMOTIVE AVEC MOTEUR ELECTRIQUE SOUTENU PAR UN PALIER EXTERNE

English Abstract

The present invention provides an externally mounted assembly for supporting a rotatable shaft member driven by an electric motor. The externally mounted assembly comprises a bearing support member disposed on a substantially vertical plane and a bearing member mounted on the bearing support member. Such bearing member is connectable with the rotatable shaft member for supporting such rotatable shaft member thereby reducing extraneous vertical and horizontal movement of such rotatable shaft member while permitting such rotatable shaft member to rotate freely.

French Abstract

La présente invention concerne un ensemble monté de façon externe et destiné à supporter un élément d'arbre rotatif entraîné par un moteur électrique. L'ensemble monté de façon externe comprend un élément de support de palier disposé sur un plan sensiblement vertical et un élément de palier monté sur l'élément de support de palier. Cet élément de palier peut être raccordé à l'élément d'arbre rotatif pour supporter l'élément d'arbre rotatif et ainsi réduire le déplacement vertical et horizontal externe de l'élément d'arbre rotatif tout en permettant la rotation libre de l'élément d'arbre rotatif.

Claims

We claim:

1. An assembly for supporting one end of a rotatable shaft
member of a compressor driven by an electric motor, said
assembly comprising:
a) a bearing support member secured to a housing for such
electric motor, said bearing support member disposed
substantially perpendicular to a longitudinal axis of such
rotatable shaft member of such compressor, said bearing support
member including an annular projecting portion; and
b) a bearing member carried by said annular projecting
portion of said bearing support member and engageable with such
one end of such rotatable shaft member of such compressor for
supporting such rotatable shaft member in a manner to thereby
reduce extraneous vertical and horizontal movement of such
rotatable shaft member while permitting such rotatable shaft
member to rotate freely, said bearing member is connected to
such one end of such rotatable shaft member that is opposite an
end of such rotatable shaft member connected to a hub and wheel
of a cooling fan of such air compressor.

2. An assembly for supporting a rotatable shaft member of a
compressor driven by an electric motor, according to claim 1,
wherein said bearing member is a split type bearing.

3. An assembly for supporting a rotatable shaft member of a
compressor driven by an electric motor, according to claim 1,
wherein said assembly is mounted externally to such motor
housing.

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4. An assembly for supporting a rotatable shaft member of a
compressor driven by an electric motor, according to claim 1,
wherein said bearing member further includes an aperture
permitting said one end of said rotatable shaft member to
protrude.

5. An assembly for supporting a rotatable shaft member of a
compressor driven by an electric motor, according to claim 1,
wherein said annular projecting portion projects inwardly
towards said cooling fan.

6. In combination with a multi-cylinder two-stage air
compressor in which an electric motor drives a rotatable shaft
member of said air compressor, the improvement comprising an
external assembly mounted to said electric motor for supporting
one end of said rotatable shaft member of said air compressor,
said external assembly mounted to said electric motor including:
a) a bearing support member secured to a housing for said
electric motor, said bearing support member disposed
substantially perpendicular to a longitudinal axis of said
rotatable shaft member of said compressor, said bearing support
member including an annular projecting portion; and
b) a bearing member carried by said annular projecting
portion of said bearing support member and engageable with said
one end of said rotatable shaft member of said compressor for
supporting said rotatable shaft member in a manner to thereby
reduce extraneous vertical and horizontal movement of said
rotatable shaft member while permitting said rotatable shaft
member to rotate freely, said bearing member is connected to
said one end of said rotatable shaft member that is opposite an
end of said rotatable shaft member connected to a hub and wheel




of a cooling fan of said air compressor.

7. A combination of a multi-cylinder two-stage air
compressor and an external assembly mounted to said electric
motor for supporting a rotatable shaft member driven by an
electric motor, according to claim 6, wherein said bearing
member is a split type bearing.

8. A combination of a multi-cylinder two-stage air
compressor and an external assembly mounted to said electric
motor for supporting one end of a rotatable shaft member driven
by an electric motor, according to claim 7, wherein said bearing
support member further includes an aperture permitting said one
end of said rotatable shaft member to protrude.

9. A combination of a multi-cylinder two-stage air
compressor and an external assembly mounted to said electric
motor for supporting one end of a rotatable shaft member driven
by an electric motor, according to claim 7, wherein said annular
projecting portion projects inwardly towards said cooling fan.

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Description

CA 02326788 2004-O1-06
LOCOMOTIVE AIR COMPRESSOR WITH AN ELECTRIC
MOTOR SUPPORTED BY AN EXTERNAL BEARING
FIELD OF INVENTION
The present invention relates, in general, to an air-
cooled multi-cylinder, two-stage air compressor and motor
combination for a railway locomotive and, more particularly,
the present invention relates to a crankshaft of such air
compressor driven by an electric motor being supported by an
external bearing.
BACKGROUND OF THE INVENTION
It is well known that multi-cylinder air compressors are
used on freight and passenger locomotives to supply compressed
air to the operating and control equipment of a railway air
brake system. Many of these prior art air compressors have a
pair of low pressure cylinders and a high pressure cylinder
mounted on and supported by a crankcase in the usual manner and
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contain pistons which are actuated by connecting rods driven by
a rotary crankshaft. One end of the crankshaft is coupled with
and driven by a suitable rotatable prime mover, such as an
electric motor. The other end of the crankshaft is keyed and
threadably attached by a locknut to the hub and wheel of a
cooling fan assembly.
There are advantages of having the compressor directly
driving the cooling fan. When the demand and speed of the air
compressor increase, the speed and cooling capacity of the fan
is proportionally increased. The fan can only stop turning
when the compressor stops working or ceases to rotate. It has
been found that the use of a separate electric motor for
driving the cooling fan is unreliable since failure of the
motor would result in the loss of the cooling effect and could
allow the temperature of the rotating compressor to rise to
dangerously high levels which could cause deterioration of the
lubricating oil and could result in seizure of the air
compressor.
The crankshaft driven by the electric motor does not, in
prior art, have any support on the motor end of the shaft.
This is the opposite end of the shaft from the fan. As the
shaft rotates, in time, it may tend to vibrate and may possibly
wobble. Any movement of the shaft, other than the rotatable
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movement which it is designed to have, may cause problems with
the motor.
Proper operation requires that there be a space between
the stator and the rotating portion of the motor. This space
must be maintained. If the rotor contacts or rubs against the
stator, problems with the motor may occur. On the other hand
it is also important to keep the space between the stator and
rotor to a minimum because as the space increases there is a
loss of efficiency and of the power of the motor. Thus, the
space is necessary but it must be kept as small as possible.
When the shaft vibrates or wobbles it may cause the rotor to
rub against the stator and, thus, adversely affect the motor.
SUMMARY OF THE INVENTION
The present invention provides an external mount assembly
for supporting a rotatable shaft member driven by an electric
motor. The external mount assembly comprises a bearing support
member being disposed in a substantially vertical plane and a
bearing member mounted on the bearing support member. Such
bearing member is connectable with the rotatable shaft member
for supporting such rotatable shaft member thereby reducing
extraneous vertical and horizontal movement of such rotatable
shaft member while permitting such rotatable shaft member to
rotate freely.
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A second embodiment of the invention provides that in
combination with a multi-cylinder two-stage air compressor in
which an electric motor is used to drive a rotatable shaft
member of said air compressor, there is an external mount for
supporting the rotatable shaft member of the air compressor.
Such external mount comprises a bearing support member disposed
in a substantially vertical plane and a bearing member mounted
on the bearing support member. Such bearing member is
connectable to the rotatable shaft member of the air compressor
for securing the rotatable shaft member thereby reducing
extraneous vertical and horizontal movement of the rotatable
shaft member while permitting such rotatable shaft member to
rotate freely.
OBJECTS OF THE INVENTION
It is, therefore, one of the primary objects of the
present invention to provide a support for the crankshaft
external to the motor housing in an air compressor/electric
motor combination so as to reduce any vibration of the shaft.
It is also an object of the present invention to provide
an outside support for the crankshaft in an air
compressor/electric motor combination so as to reduce the
possibility of the rotor rubbing against the stator.
An additional object of the present invention is to
provide a support for the crankshaft in an air
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compressor/electric motor combination that is mounted on the
housing of the electric motor.
These and various other objects and advantages of this
invention will become apparent after a full reading of the
following detailed description, particularly, when read
in conjunction with the attached drawings as described below
and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is an axonometric prior art drawing of a
mufti-cylinder, two stage air compressor.
Figure 2 is a block schematic diagram of an embodiment of
the invention in combination with a mufti-cylinder, two stage
air compressor of the type shown in Figure 1.
BRIEF DESCRIPTION OF THE
PRESENTLY PREFERRED AND ALTERNATE
EMBODIMENTS OF THE INVENTION
Prior to proceeding with the more detailed description of
the present invention it should be noted that, for the sake of
clarity, identical components which have identical
functions have been designated by identical reference numerals
throughout the several views illustrated in the drawings.
Reference is now made to Figure 2. Illustrated therein is
a block diagram of the present invention in combination with a
mufti-cylinder, two stage air compressor, generally designated
as 10, coupled with a predetermined electric motor, generally

CA 02326788 2000-11-23
designated as 20. Such multi-cylinder, two stage air
compressor 10 contain pistons which are actuated by connecting
rods driven by a rotary crankshaft 2. One end of the
crankshaft 2 is to the hub and wheel of a cooling fan
assembly 16. The other end of the crankshaft 2 is driven by a
predetermined electric motor 20. Over a period of time the
crankshaft 2 as it rotates may tend to vibrate or wobble. Any
movement of the crankshaft 2 other than the rotatable movement
which it is designed to have can create problems.
Proper operation of the motor requires that there be a
space between the stator 4 and the rotor 6, which is the
rotating portion of the motor. This space must be maintained.
If rotor 6 comes into contact with or rubs against the
stator 4, problems with the motor 20 may occur. It is also
important that this space be kept to a minimum because as the
space increases there is a loss of efficiency and of the power
of the motor.
The present invention provides an external support,
generally designated 30, to support the crankshaft 2 and thus
prevent or at least minimize any extraneous vertical or
horizontal movement of the crankshaft 2. There is an upright
bearing support member 12. A bearing member 14 is mounted on
such upright bearing support member 12. Such bearing member 14
is connectable with the crankshaft 2 of such air compressor 10.
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Such bearing member 14 and such upright bearing support
member 12 supports the crankshaft thereby minimizing any
extraneous movement of the crankshaft 2. Since the bearing
member 14 freely rotates it does not impede any rotatable
movement of the crankshaft 2. In an embodiment of the
invention such bearing member 14 is a split bearing. It is
also an embodiment of the invention that such bearing member 14
is connected to an outer end of such crankshaft 2.
The upright bearing support member 12 is connected to the
motor housing that is presently used to enclose such motor 20.
The connection may be made by modifying the cover portion of
such housing such that the bearing member 14 can come in
contact with and secure the crankshaft 2. However, it is
within the scope of the invention that such upright bearing
support member 12 may replace the present cover portion of the
motor housing of such predetermined electric motor 20. Such
external mount 30 may be included in new compressor assemblies
and it may be retrofitted into air compressor units that are
presently in use.
While both the presently preferred and a number of
alternative embodiments of the present invention have been
described in detail above it should be understood that various
other adaptations and modifications of the present invention
can be envisioned by those persons who are skilled in the
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relevant art of air compressor systems without departing from
either the spirit of the invention or the scope of the appended
claims.
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Representative Drawing