Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
1062215
The invention relates to a motor compressor unit comprising
a motor having a stator with an axial bore, a rotor mounted in
the bore, a motor drive shaft carrying the rotor, a compressor,
and means for supporting the compressor and the stator and having
a bearing for the shaft; the stator having windings which extend
transversely across one end of the stator bore and which leave
an opening through which the bearing extends, an annular disc
disposed intermediate the stator windingsand the rotor for
supporting the stator windings, the disc having a diameter
slightly less than the diameter of the stator bore and is
provided with means for fixing the disc in position relative
to the stator.
A refrigerant compressor of this kind is known, in which
the chordlike end connection conductors are provided at the
bottom of the stator and the supporting device has the form of
a substantia~y closed cap, of which the edge is seated on the
end of the packet of stator laminations, its main surface is
intended to prevent a collision between the end connection
conductors and the rotor, and which carries a central cylindrical
projection serving as a shock absorber. The diameter of the cap
is larger than the internal diameter of the stator. At the
periphery, the cap is radially slotted and expands automatically
after it has been pushed through the stator. Alternatively, a
rigid cap of the same diameter as the internal stator diameter
can also be used, in which spreading webs
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are provided at the outer periphery that must be passed
through the grooves and that spread behind the packet of
laminations in their final position. This type of assembly
makes it necessary for the spacing between the end cGnneCtion
conductors and the end face of the packet of stator lamin-
ations to be slightly larger than the corresponding dimen-
sion of the cap because otherwise there will be inadequate
spreading or no spreading at all. The resultant play could
become larger during operation and give rise to noise. In
addition, the assembly itself is cumbersome.
The invention is based on the problem of providing
a refrigerant compressor of the aforementioned kind, in
which the creation of noise is prevented by the supporting
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device and the assembly is simplified.
This problem is solved according to the invention
in that the end connection conductors guided along chords
are provided at the top of the stator and leave a passage
for the main bearing between each other, and that the sup-
porting device for the most part leaves a spacing between -
itself and the packet of stator laminations and consists
of an annular disc provided with holding means and having an
outer periphery of smaller diameter than the internal diameter
of the stator.
With this construction, use is made of the fact
that the end connection conductors tend to sag under gravity
during any oscillating movement. They therefore come to lie
against the supporting device to an ever increasing extent
- and in this way prevents movement of the supporting device
I that may give rise to noise. This also applies if the support-
~ ing device must initially be mounted with a certain play
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between the end connection conductors and the packet of stator
laminations. At the top, however, no cap can be used because,
since it is penetrated by the main bearing, it would have to
be practically completely closed because then there could
; neither be the normal suction gas circulation in the region
of the rotor nor withdrawal of the oil through the apertures
in the suppor~ing member. In contrast, the annular disc pen-
etrated by the main bearing leaves an adequate flow section
free at the outer periphery. By reason of its small outer
diameter, it can also be easily assembled. Surprisingly, it
has been found that such an annular disc is a sufficient sup-
port because the main consideration is the support of the cen-
tral and consequently longer end connection conductors whereas
the outer and thus shorter end connection conductors have an
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adequate stiffness possibly even without any support. It is
a further advantage that the normal winding heads having a
larger amount of conductor material can now dip into the oil
sump, resulting in more intensive cooling. In addition, the
motor is accessible from below, so that, during assembly, the
supporting device will not hinder the introduction of centre-
ing probes in the air gap between the rotor and stator.
` With particular advantage, arms adjoin the ex-
terior of the annular disc perpendicular to the main
direction in which the end connection conductors extend. These
arms enable the support of the comparatively short outer end
` connection conductors.
The holding means may take several forms. For ex-
ample, they may comprise two elastically yielding arms which
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spring radially from the annular disc and are supported on
the end of the l~minated stator. ~hese two arms are compara-
tively easily pressed together. They may also serve as
supporting arms for the outer end connection conductors.
~ esirably, the arms extend at an angle to the plane
of the annular disc that is substantially normal to the motor
axis, this resulting in easier compressibility and more
stiffness in the built-in condition.
In addition, the arms may be provided with supporting
feet extended in the peripheral direction so as to increase
the supporting surface on the packet of stator laminations.
However, it is particularly preferred to use holding
means which secure the supporting device to the main bearing.
Since the supporting device is secured by such holding means
to the main bearing and thus to the supporting member, a
support on the packet of stator laminations can be of compara-
tively weak construction or completely omitted. In the last-
mentioned case, there would no longer be any need to pay
attention to an adaptation between the supporting devices and
the spatial conditions between the end connection conductors
and the packet of stator laminations.
It is even possible to secure the supporting de-
vice to the main bearing such that the annular disc abuts
against the end connection conductors under pre-stress. This
even more intensively suppresses the tendency of these
conductors to oscillate.
It is of particular advantage if the holding means
comprise a collar that can be pushed over the outer peripheral
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surface of the main bearing. This results in a uniform cir-
cumferential engaging surf~ce which ensures a particularly
good hold.
Further, a groove may be provided in the ou~er
peripheral surface of the main bearing in which part o~ the
collar engages. This results in an extraordinarily secure
attachment.
In particular, the collar may be substantially
cylindrical and have an internal bead elastically snapping into
the groove. To achieve the elasticity, the cylindrical collar
may be at least partially axially slotted.
In another embodiment, the collar converges sub-
- stantially conically towards the rotor and is radially slotted
or toothed at the inner periphery. With such a construction,
the securing forces increase with an increase in the load on
the annular disc caused by the end connection conductors.
The invention will now be described in more detail
s with reference to examples illustrated in the drawing, wherein:
Fig. 1 is a diagrammatic longitudinal section through
a hermetically encapsulated refrigerant compressor according
to the invention;
:
Fig. 2 is a side elevation of the supporting device
used in Fig. l;
Fig. 3, shown in the second page of drawings, is a
plan view of the stator of a refrigerant compressor according
to the invention with a section taken through the main bearing;
Fig. 4 is a plan view of the supporting element used
; in Fig. 3;
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Fig. 5 is a section through the supporting element
used in Fiq. 3;
Fig. 6 is a partial section together with a further
example of the invention;
Fig. 7 is a section throu~h the unloaded supporting
element of Fig. 6, and
Fig. 8 is a plan view of the Fig. 6 supporting element.
The refrigerant compressor illustrated in Fig. l
is suspended in a hermetically closed capsule l by means of
springs 2~ The springs engage a supporting member 3 at the
top of which there is a refrigerant compressor 4. The latter
comprises a cylinder 5, a cylinder head 6 and a piston 8
driven through a connecting rod 7. At the bottom of the support-
ing member 3 there is the stator 9 of the electric motor drive.
It comprises a packet lO of stator laminations and a stator
winding ll which, at its lower end, has a normal winding head
12 disposed completely beyond the internal diameter 13 of the
packet 10 of stator laminations and dipping into the oil sump
-~ 14. Provided at the top there are end aonnection conductors
i 20 15 of the main winding, which extend substantially along a
- chord across the cross-section disposed within the internal
diameter 13 of the stator, as more clearly shown in Fig. 3.
;~ The end connector conductors 16 of the auxiliary resistance
winding, however, are placed around the outside of the internal
diameter 13 of the stator.
The supporting member 3 further comprises a central
main bearing 17 in which a motor shaft 18 is mounte~. This
bearing is integral at the top with a crank l9 on which the con-
necting rod 7 is mounted. Beneath the main bearing 17, the motor
shaft 18 carries a packet 20 of rotor laminations, the
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short-circuiting rings 21 and 22 of its conductor cage being
visible. An oil supply tuhe 23 projects into the oil sump 14.
The remainder of the oil distribution system by means of which
oil is fed to the lubricating points in the main bearing 17 at
the crank pin 19 and i~ the cylinder 5 and with which oil is
also circulated for cooling purposes is not shown in more detail.
Only holes 24 in the supporting member 3 indicate that oil
flowing off from the top can reach the motor chamber located
" thereunder.
The end connection conductors 15 are supported by a
supporting device 25. This consists of an annular disc 26 on
which at least the internal conductors 15 of longer length are
supported, and a collar 28 which is provided with axial slots 27
and, at the top end, with an internal bead 29 which is engaged in
a groove 30 at the outer peripheral surface of the main bearing 17.
~ If outer and consequently shorter end connection conductors 15
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receive no support, this is generally of no consequence because ¦
they are stiffer by reason of their shorter length.
` During assembly, the motor shaft 18 is first of all
~ 20 inserted in the main bearing 17 and its crank pin 19 is connected -
1 , .
: to the connecting rod 7. The stator 9 is then provisionally
- attached to the supporting member 3. The supporting device 25
is now pu$hed onto the main bearing 17 through the free cross-
section of the packet 10 of stator laminations until 'he bead
` 29 engages in the groove 30. The packet 20 of rotor laminations
is thereafter shrunk onto the motor shaft 18 and the stator 10
is centred with respect to the rotor 20 and in this position
secured to the supporting member 3. Finally, the assembled
- unit is secured to the capsule 1 by way of
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the s~rings 2 and the capsule is closed.
During transport and operation, oscillations of the end
connection conductors lS are wlavoidable. They cannot, however,
- come into contact with the short-circuiting ring 21 of the rotor
20 because they are supported by the supporting device 25.
However, because of gravitational forces, deformation of the
end connection conductors 15 are unavoidable in a downward
direction. Such deformation leads to a more intensive abutment
against the supporting device 25 and the resultant pre-stress
reduces subsequent oscillations. One can even ensure during
assembly that the annular disc 26 lies against the end connection
conductors 15 under a certain amount of pre-stress so as to re-
duce their tendency to oscillate. Particularly when the sup-
porting device 25 consists of an elastically yielding material
such as plastics, slight deformation can be used to apply a
correspondingly large amount of pre-stress to this annular
disc 26.
In the Fig. 3 embodiment, a supporting device 31 is
used comprising a planar annular disc 32 surrounding the main
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bearing 17 and two radial arms 33 serving as holding means which
extend at an angle to the annular disc 32 and are provided with
supporting feet 34 extend~d in the peripheral direction. These
supporting feet rest on the end face 35 of the packet 10 of
stator laminations.
This supporting device 31 can be built into the stator
before the latter is secured to the supporting member 3. For this
purpose it is merely necessary slightly to compress the two
inclined arms 33 so that the supporting device 31 can be
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introduced through the int:ernal cross-section of the stator 10.
In the final po~sition, the supporting feet 34 elastically
increase their diameter and lie on the packet 10 of stator
laminations. T~le play necessary for this is automatically re-
duced during transport or operation when the end connection
conductors 15 sag under their own weight.
; Fig. 3 indicates that the end connection conductors
15 at the centre are spread apart to such an extent that they
form a passage 36 for the main bearing 17. The individual winding
sections could also be axially superposed. In any case, a
comparatively narrow annular disc 32 will suffice. The arms 33 -
~ are orientated so that they can also serve as a support for
- the shorter outer end connection conductors 15.
Fig. 6 to 8 illustrate a third embodiment in which
~: the supporting device 37 is shown to a larger scale in Figs. 7
and 8 than in Fig. 6. Again, an annular disc 38 is provided.
It comprises an arm 39 at each of two opposed sides. The
holding means are formed by a collar 40 which conically con-
verges towards the motor. Either radial incisions 41 or teeth
`~l 20 42 are provided at its inner radius. Partly because of this
configuration and partly because of the inherent elasticity of
the material such as plastics, this supporting device 37 can be
- pushed onto the main bearing 17 until the internal periphery
of the collar 40 engages in the groove 30. In this embodiment,
this takes place under pre-stress, so that the annular disc 38
bends downwardly adjacent to the arms 39, whereby its secure
engagement in the groove 30 is increased further. The arms 39
; do not here serve as holding means but merely for supporting the
shorter outer end connection conductors 15.
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Fig. 3 shows that the breadth of the annular disc
can be kept so small that a considerable passage cross-section
is left beyond it, through which there can be free circulation
of the suction gases disposed in the motor chamber and through
which oil can also flow downwardly without hindrance. It will
also be evident that for such a supporting device a very small
amount of material is necessary.
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