U.S. patent application number 11/377168 was filed with the patent office on 2006-08-10 for method for mounting a drive shaft of a compressor.
This patent application is currently assigned to Danfoss Compressors GmbH. Invention is credited to Frank Holm Iversen, Heinz Otto Lassen, Marten Nommensen, Christian Petersen, Beate Sonksen.
Application Number | 20060175919 11/377168 |
Document ID | / |
Family ID | 35454788 |
Filed Date | 2006-08-10 |
United States Patent
Application |
20060175919 |
Kind Code |
A1 |
Iversen; Frank Holm ; et
al. |
August 10, 2006 |
Method for mounting a drive shaft of a compressor
Abstract
The invention concerns a method for mounting a drive shaft (19)
of a compressor, particularly a hermetical refrigerant compressor,
which has a motor with a stator (1) and a rotor (23), connected
with the drive shaft (19) and located in a rotor opening (4) of the
stator (1), a first bearing support (8) and a second bearing
support (29) being connected with the stator (1), a first bearing
(15) for the drive shaft (19) being mounted in the first bearing
support (8) and a second bearing (28) for the drive shaft (19)
being mounted in the second bearing support (29). It is endeavoured
to provide a method for mounting a drive shaft, in which the use of
components with relatively large manufacturing tolerances will
still result in a good alignment of the drive shaft in relation to
the stator. For this purpose, at least the first bearing support
(8) is provided with a positioning stop for the first bearing (15)
after mounting the first bearing support (8) on the stator (1).
Inventors: |
Iversen; Frank Holm;
(Padborg, DK) ; Lassen; Heinz Otto; (Flensburg,
DE) ; Nommensen; Marten; (Flensburg, DE) ;
Petersen; Christian; (Hattstedt, DE) ; Sonksen;
Beate; (Hattstedt, DE) |
Correspondence
Address: |
MCCORMICK, PAULDING & HUBER LLP
CITY PLACE II
185 ASYLUM STREET
HARTFORD
CT
06103
US
|
Assignee: |
Danfoss Compressors GmbH
Flensburg
DE
|
Family ID: |
35454788 |
Appl. No.: |
11/377168 |
Filed: |
March 16, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11135873 |
May 24, 2005 |
|
|
|
11377168 |
Mar 16, 2006 |
|
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Current U.S.
Class: |
310/90 |
Current CPC
Class: |
H02K 15/16 20130101;
Y10T 29/49009 20150115; H02K 5/1672 20130101; Y10T 29/53
20150115 |
Class at
Publication: |
310/090 |
International
Class: |
H02K 5/16 20060101
H02K005/16; H02K 7/08 20060101 H02K007/08 |
Foreign Application Data
Date |
Code |
Application Number |
May 26, 2004 |
DE |
10 2004 025 678.0 |
Claims
1-11. (canceled)
12. A tool for mounting a drive shaft bearing to a stator, the tool
comprising: a first support part having a first support part
diameter and a first support part surface, the first support part
diameter substantially corresponding to a diameter of a rotor
opening of the stator, and the first support part surface including
a first opening extending into the first support part; and a second
support part having a second support part surface opposing the
first support part surface, the second support part surface
including a second opening extending into the second support part
and opposing the first opening; wherein the first support part is
incapable of radial movement when at least partially inserted into
the rotor opening.
13. The tool of claim 12, wherein the first opening is positioned
in the first support part surface so as to substantially correspond
to a desired position of the drive shaft bearing relative to the
rotor opening.
14. The tool of claim 12, wherein the first and second support part
surfaces are adapted to selectively engage opposing sides of a
bearing support positioned across the rotor opening.
15. The tool of claim 12, wherein the first opening has an inner
cross-sectional profile substantially corresponding to an outer
cross-sectional profile of the drive shaft bearing.
16. The tool of claim 12, further comprising a punching device
disposed in the second opening and displaceable so as to at least
partially extend into the first opening during a punching
operation.
17. The tool of claim 12, further comprising a control device
disposed in the first opening and displaceable so as to at least
partially extend into the second opening while inserting the drive
shaft bearing into a bearing support.
18. The tool of claim 17, wherein the control device includes a
projection, the projection being the portion of the control device
extending at least partially into the second opening while
inserting the drive shaft bearing into the bearing support, the
first opening having an inner cross-sectional profile and the
projection having an outer cross-sectional profile substantially
corresponding, respectively, to an outer and an inner
cross-sectional profile of the drive shaft bearing so as to inhibit
radial displacement of the drive shaft bearing while inserting the
drive shaft bearing into the bearing support.
19. A compressor motor comprising: a drive shaft; a stator having a
first stator end and a second stator end and a rotor opening
extending therebetween, the rotor opening surrounding at least a
portion of the drive shaft; a rotor mounted on the drive shaft
located in the rotor opening; a first bearing support mounted to
the stator first end and having a first positioning stop formed
therein; and a first bearing located with the first positioning
stop and rotatably supporting the drive shaft in the vicinity of
the first stator end; wherein the first positioning stop is formed
in the first bearing support after the first bearing support is
mounted to the stator first end.
20. The compressor motor of claim 19, further comprising: a second
bearing support mounted to the stator second end and having a
second positioning stop formed therein; and a second bearing
located within the second positioning stop and rotatably supporting
the drive shaft in the vicinity of the second stator end; wherein
the second bearing is located within the second positoning stop and
aligned concentrically to the rotor opening before the second
bearing stop is mounted to the stator second end.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Divisional Application of U.S. Ser.
No. 11/135,873 entitled `Method for Mounting a Drive Shaft of a
Compressor`, to Frank Holm Iversen, et al., filed on May 24, 2005,
and claims the benefit of the filing date thereof under 35 U.S.C.
.sctn.120. The present invention also claims priority from German
Patent Application No. 10 2004 025 678.0, filed on May 26, 2004.
The contents of both applications are incorporated by reference
herein.
FIELD OF THE INVENTION
[0002] The invention concerns a method for mounting a drive shaft
of a compressor, particularly a hermetical refrigerant
compressor.
BACKGROUND OF THE INVENTION
[0003] Refrigerant compressors have become products manufactured in
large numbers, and should therefore be manufactured in the most
cost effective manner possible. As, however, refrigerant
compressors are practically operating all the year round, the
energy consumption of the motor, which is required for driving the
compressor unit, must be kept as small as possible. This again
requires that, for example, the rotor and the stator are assembled
with the best possible mutual alignment to keep the air gap between
rotor and stator small, which reduces energy losses.
[0004] U.S. Pat. No. 6,095,768 shows a refrigerant compressor with
a cup-shaped stator housing, whose upper end is open. The open end
is bridged by a crossover. Self-aligning bearings for the drive
shaft are inserted both in the crosshead and in the bottom of the
stator housing. Even though these bearings permit a certain
deviation of the drive shaft from the axis of the stator, a
relatively exact alignment of the crosshead must be ensured, so
that the crosshead is perpendicular to the drive shaft.
[0005] Another refrigerant compressor is known from U.S. Pat. No.
3,762,837. Here, the drive shaft is supported on both sides of a
crankpin arrangement. The rotor is located on the other side of a
bearing. Both bearings are radially displaceable and after mounting
the motor and the compressor arrangement they have to be
individually aligned and fixed to ensure a uniform air gap between
the rotor and the stator. For the alignment, screws are loosened
and the bearings displaced. Then the screws are tightened again.
Thus, the bearings are only held by means of clamping.
[0006] EP 0 524 552 A1 shows a hermetical refrigerant compressor
with double-supported drive shaft, the upper bearing being fixed in
a block. The lower bearing is fixed on the stator by means of a
holding element, so that the rotor can align itself in relation to
the stator of the motor.
[0007] In all cases, relatively accurately manufactured components
are required to keep the air gap between the rotor and the stator
small and to align the drive shaft perpendicularly to the bearings.
A "leaning" drive shaft will eventually cause relatively heavy wear
on the bearings. Further, an insufficient alignment causes
frictional losses in the bearings, which again cause increased
energy consumption.
SUMMARY OF THE INVENTION
[0008] The invention is based on the task of providing a method for
mounting a drive shaft, which ensures a good alignment of the drive
shaft to the stator, also when using components with relatively
large manufacturing tolerances.
[0009] With a method as mentioned in the introduction, this task is
solved in that at least the first bearing support is provided with
a positioning stop for the first bearing after mounting the first
bearing support on the stator.
[0010] With this method, a uniform air gap between the rotor and
the stator is achieved, which can even be heavily reduced.
Frictional losses in the bearings are avoided. This also applies,
when relatively cheap sheet metal parts are used for the
compressor, that is, parts with relatively large manufacturing
tolerances. Firstly, the first bearing support is mounted on the
stator. This gives the bearing support an unchangeable position in
relation to the rotor opening. Then, the positioning stop for the
first bearing can be manufactured with a fixed dependence on the
position of the rotor opening. Thus, the positioning stop is not
manufactured until after the mounting of the first bearing support,
but after the manufacturing, it is no longer changed in relation to
the rotor opening. When the first bearing is then aligned on the
positioning stop, the first bearing has an exact concentrical
alignment in relation to the rotor opening.
[0011] Preferably, an edge of an opening is used as positioning
stop, said edge being manufactured after mounting the bearing
support on the stator. The first bearing is then inserted in the
opening and is then aligned to be exactly concentrical to the rotor
opening. Instead of an opening, also an impressing can be used.
[0012] Preferably, with a vertically aligned drive shaft, the
bearing support of the upper bearing is fixed on the stator, and
then the positioning stop is formed. In most refrigeration
compressors the motor is made with a vertically oriented drive
shaft. The drive shaft then "hangs" on the upper bearing, in whose
vicinity usually also the crank pin for driving the compressor
arrangement is located. In this area, an exact alignment of the
drive shaft in the rotor opening is particularly important.
[0013] It is also advantageous, when a tool is used for
manufacturing the positioning stop, at least a part of this tool
being located concentrically in the rotor opening. The rotor
opening itself is used for centring the tool for the manufacturing
of the positioning stop. Thus, it is ensured that the positioning
stop has exactly the desired alignment to the rotor opening.
[0014] It is particularly preferred that the part fills the
cross-section of the rotor opening. Thus, the rotor opening or at
least an axial section of it is filled with the tool, so that the
tool is practically no longer radially displaceable in the rotor
opening. When, then the positioning stop is formed, the positioning
stop is aligned concentrically to the rotor opening with a high
accuracy.
[0015] Preferably, a punch is used as tool. With a punch, for
example, an opening can be punched, whose edge then serves as
positioning stop.
[0016] Preferably, a bearing support is used, whose opening has
short measure in relation to the bearing, the opening being
extended to the measure of the bearing. When using a punch, this
has the advantage that after fixing the bearing support only a fine
punch step is required to bring the opening to the final measure.
This further simplifies the manufacturing process, as only little
material has to be removed, which means that the forces required to
manufacture the final opening are smaller.
[0017] Alternatively or additionally, it is ensured that a calotte
bearing is used as bearing, an area surrounding the opening being
shaped to a bearing shell by means of an impressing step. Also in
this case, the "local" manufacturing ensures that the centre of the
bearing shell lies exactly on the axis of the stator.
[0018] Preferably, the second bearing is mounted on the second
bearing support, aligned centrically to the rotor opening by means
of an auxiliary tool, which is fixed at at least two alignment
positions on the stator, the second bearing support then being
fixed on the stator. Thus, an overcorrection is avoided.
[0019] It is preferred that holes in the metal sheets of the stator
are used as alignment positions, said holes being made together
with the rotor opening. The stator is usually made of stacked metal
sheets, in which the rotor opening is made in that all the metal
sheets are provided with a punching. When making this punching,
holes can be punched at the same time for later use as fixing for
the auxiliary tool. These holes are then positioned in relation to
the rotor opening with a very high accuracy.
[0020] It is also advantageous that the second bearing is aligned
after mounting on the drive shaft. In this case, it is ensured that
the axis of the drive shaft corresponds exactly to the axis of the
stator.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] In the following the invention is described on the basis of
a preferred embodiment in connection with the drawings,
showing:
[0022] FIG. 1 is a schematic cross-section through a stator;
[0023] FIG. 2 is a perspective view of the stator;
[0024] FIG. 3 is a sectional view according to FIG. 1 with inserted
tool;
[0025] FIG. 4 is a perspective view according to FIG. 2 after
forming an opening for the first bearing;
[0026] FIG. 5 is a sectional view of the stator with inserted upper
bearing;
[0027] FIG. 6 is a sectional view of the stator with inserted drive
shaft;
[0028] FIG. 7 is a sectional view with inserted rotor; and
[0029] FIG. 8 is a sectional view with inserted lower bearing.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0030] FIG. 1 shows a stator 1 of a motor, which is used for
driving a compressor, particularly a refrigerant compressor. The
stator 1 has a sheet pack 2 and a coil, of which coil ends 3 are
shown. The sheet pack 2 surrounds a rotor opening 4. The rotor
opening 4 is made in that already during the punching; the sheets
forming the sheet pack 2 are provided with a central opening, so
that the rotor opening 4 occurs, when the sheets of the sheet pack
2 are stacked.
[0031] A compressor block 5 is mounted and fixedly connected, for
example by welding, on the outside of the sheet pack 2. The
compressor block 5 can, for example, be a sheet metal part. The
compressor block 5 has a basic unit 7 extending substantially
parallel to the axis 6 of the stator 1, on which unit 7 a first
bearing support 8 is fixed, for example by welding. After fixing on
the basic unit 7, the first bearing support 8 forms a one-side
suspended beam, which extends across the rotor opening 4. Both the
basic unit 7 and the first bearing support 8 can be made in a
cost-effective manner from punched and shaped sheet metal parts.
Above the first bearing support 8, the basic unit 7 has a mounting
opening 9, which will eventually serve the accommodation of the
compressor unit itself.
[0032] In the section of the first bearing support 8, which could
also be called "upper bearing support", crossing the rotor opening
4, an opening 10 is made for a first bearing, which is intended for
supporting the drive shaft. For this purpose, a lower support part
11 of a punching device, for example an expansion mandrel, is
inserted in the stator opening 4. The lower support part 11 fills
the stator opening 4, and is no longer movable in the radial
direction. The lower support part 11 is engaged against the lower
side of the first bearing support 8. An upper support part 12 of
the punching device is mounted on the first bearing support 8 from
the upper side, before a punching tool 13 punches the opening 10 in
the first bearing support 8. This opening 10 is thus exactly
concentrical to the axis 6 of the stator opening 4, no matter if
the first bearing support 8 has been mounted exactly enough on the
basic unit 7 of the compressor block 5 and thus on the stator 1 or
not. The exact alignment of the opening 10 in relation to the rotor
opening 4 will not be changed during the following mounting steps,
as the compressor block 5 remains fixedly mounted on the stator
1.
[0033] The opening 10 in the first bearing support 8 can also be
"pre-manufactured" with a predetermined short measure. The first
bearing will not yet fit into this pre-manufactured opening 10.
However, the opening can be extended to its final measure by means
of a fine punching step. This further simplifies the production
process, as only little material has to be removed and the required
forces are smaller.
[0034] When a calotte bearing is used as first bearing (not shown),
the area of the first bearing support 8 surrounding the first
opening 10 can be shaped by means of an impressing step in such a
manner that a bearing shell 14 for the calotte bearing appears.
Also in this case, the process shown ensures that the centre of the
bearing shells is placed exactly on the axis 6 of the stator 1.
[0035] FIG. 5 now shows that a bearing bush 15 is inserted in the
opening 10. The bearing bush 15 can be made of sintered metal and
has a circumferential, radially projecting flange 16, which bears
on the first bearing support 8 from the upside. The bearing bush 15
is pressed into the first bearing support 8, a control device 17,
which is guided in the lower support part 11, fixing the radial and
axial position of the bush 15. The force required for pressing in
can be supplied by the upper support part 12 of the punch. Instead
of the upper support part 12, also a corresponding pressing tool
can be used. During pressing, the upper support part 12 is guided
on the control device 17, or rather a projection 18 penetrating the
opening 10, so that here radial forces cannot occur either, which
could lead to a displacement of the bearing bush 15.
[0036] FIG. 6 shows that a drive shaft 19 is inserted in the
bearing bush 15. The drive shaft 19 now has an axis, which is
congruent with the axis 6 of the stator 1. Under the effect of the
gravity it initially hangs vertically downwards. At the upper end,
the drive shaft 19 has a carrier disc 20, on which a crankpin 21
and a balancing weight 22 are fixed. The carrier disc 20 bears on
the flange 16 of the bearing bush 15, so that here the bearing bush
15 does not only form a radial bearing, but also an axial bearing.
The drive shaft 19 can simply be inserted in the bearing bush 15
from the top.
[0037] From FIG. 7 it appears that in a further mounting step a
rotor 23 is pressed onto the drive shaft 19, whereas a hold-on (not
shown in detail) at the crank-side upper end of the drive shaft 19
adopts the pressing forces. To simplify the pressing process, the
rotor 23 can be heated up before mounting. After cooling off, it
shrinks onto the shaft.
[0038] FIG. 8 shows the last step of the mounting. An auxiliary
tool 24 with pins 25 is inserted in the positioning openings 26
(FIGS. 2 and 4), which are formed in the sheets of the sheet pack
2. These positioning openings 26 are manufactured in the same
punching process, in which also the cut-outs are punched, which
will form the rotor opening 4. Thus, the positioning openings 26
have a very accurated spatial relation to the rotor opening 4.
[0039] The auxiliary tool 24 has a central opening 27, into which
the top of the drive shaft 19 is inserted. Before applying the
auxiliary tool 24, however, a second bearing 28, which is inserted
in a second bearing support 29, is pushed onto the drive shaft 19.
When, through the bearing bush 15 forming the first bearing, the
drive shaft 19, and the auxiliary tool 24, have been positioned
accurately in relation to the sheet pack 2 of the stator 1, the
second bearing support 29 is fixed, for example by welding, on a
leg 30 projecting from the basic unit 7. However, the second
bearing support 29 can also be fixed on the leg 30 by screwing or
riveting.
[0040] For the second bearing 28, a calotte bearing is preferred,
to balance possible angle errors between the bearing support 29 and
the drive shaft 19, if the second bearing support 29 does not
extend exactly at right angles to the drive shaft 19.
[0041] After fixing the second bearing support 29 on the basic unit
7, it is thus ensured that the centres of the bearing bush 15 and
the second, or lower, bearing 28 as well as the longitudinal axes
of the two bearings lie exactly in the longitudinal axis 6 of the
stator.
[0042] All mounting steps shown can to a large extent be automated.
Also when using formed sheet metal parts, a high-precision
alignment of the rotor 23 in relation to the stator 1 can thus be
realised. This permits the reduction of the air gap between the
rotor 23 and the stator sheet pack 2, which will also later give a
cost-effective mode of operation.
[0043] While the present invention has been illustrated and
described with respect to a particular embodiment thereof, it
should be appreciated by those of ordinary skill in the art that
various modifications to this invention may be made without
departing from the spirit and scope of the present invention.
* * * * *