U.S. patent application number 13/131032 was filed with the patent office on 2011-09-22 for impeller for a fan.
This patent application is currently assigned to BSH BOSCH UND SIEMENS HAUSGERATE GMBH. Invention is credited to Rastislav Andrejco, Adolf Feinauer, Michaela Malisi.
Application Number | 20110229341 13/131032 |
Document ID | / |
Family ID | 41435303 |
Filed Date | 2011-09-22 |
United States Patent
Application |
20110229341 |
Kind Code |
A1 |
Andrejco; Rastislav ; et
al. |
September 22, 2011 |
IMPELLER FOR A FAN
Abstract
An impeller for a fan having a hub that can be easily fastened
to a shaft is disclosed. A multiplicity of vanes is fastened to the
hub. At least one elastic damping body is provided in the hub
between the receptacle and the vanes to damp the transfer of
vibrations from the shaft to the vanes, and prevent vibration of
the vanes relative to each other. A slotted central sleeve in the
inner section of the hub forms the receptacle for the shaft and is
surrounded by an annular spring.
Inventors: |
Andrejco; Rastislav; (Vranov
nad Toplou, SK) ; Feinauer; Adolf; (Giengen, DE)
; Malisi; Michaela; (Heidenheim, DE) |
Assignee: |
BSH BOSCH UND SIEMENS HAUSGERATE
GMBH
Munich
DE
|
Family ID: |
41435303 |
Appl. No.: |
13/131032 |
Filed: |
November 16, 2009 |
PCT Filed: |
November 16, 2009 |
PCT NO: |
PCT/EP09/65184 |
371 Date: |
May 25, 2011 |
Current U.S.
Class: |
416/244R |
Current CPC
Class: |
F04D 19/002 20130101;
F04D 29/668 20130101; F04D 29/329 20130101; F04D 29/263 20130101;
F04D 29/663 20130101 |
Class at
Publication: |
416/244.R |
International
Class: |
F01D 25/00 20060101
F01D025/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 10, 2008 |
DE |
10 2008 054 497.3 |
Claims
1-15. (canceled)
16. An impeller for a fan having a shaft, said impeller comprising:
a plurality of vanes; a hub having an outer ring to which the vanes
are fastened and an inner section in which a receptacle for the
shaft is formed; at least one elastic damping body arranged between
the receptacle and the vanes that connects the inner section of the
hub to the outer ring of the hub; and a slotted central sleeve in
the inner section of the hub, said slotted central sleeve forming
the receptacle, said slotted central sleeve being surrounded by an
annular spring.
17. The impeller of claim 16, for use in a domestic appliance.
18. The impeller of claim 16, wherein the damping body occupies an
annular intermediate space between the outer ring of the hub and
the inner section of the hub.
19. The impeller of claim 16, wherein a plurality of damping bodies
are arranged in a circumferentially distributed manner in an
annular intermediate space between the outer ring of the hub and
the inner section of the hub.
20. The impeller of claim 19, wherein the ring has recesses in
which the damping bodies positively engage.
21. The impeller of claim 20, wherein the recesses are
undercut.
22. The impeller of claim 16, wherein the inner section has
recesses in which the damping bodies positively engage.
23. The impeller of claim 22, wherein that the recesses are
undercut.
24. The impeller of claim 16 wherein the damping body is made of a
material having a higher elasticity than the outer ring of the
hub.
25. The impeller of claim 16 wherein the damping body is made of a
material having a higher elasticity than the inner section of the
hub.
26. The impeller of claim 25, wherein the material of the damping
body is a silicone or a rubber.
27. The impeller of claim 16, wherein the damping bodies are
connected in one piece with the outer ring of the hub and the inner
section of the hub.
28. The impeller of claim 16, wherein the inner section of the hub
comprises an annular wall running annularly around the sleeve at a
distance.
29. The impeller of claim 28, wherein the central sleeve and the
annular wall are connected in one piece.
30. The impeller of claim 28, further comprising a connecting piece
arranged at an end face of the hub for connecting the central
sleeve to the annular wall.
31. The impeller of claim 16 wherein at least one damping body is
arranged in an annular intermediate space between the outer ring of
the hub and the inner section of the hub so that the at least one
damping body is axially offset relative to the spring.
32. A fan, comprising: a shaft; an impeller having a plurality of
vanes; a hub having an outer ring to which the vanes are fastened
and an inner section in which a receptacle for the shaft is formed;
at least one elastic damping body arranged between the receptacle
and the vanes that connects the inner section of the hub to the
outer ring of the hub; and a slotted central sleeve in the inner
section of the hub, said slotted central sleeve forming the
receptacle, said slotted central sleeve being surrounded by an
annular spring.
Description
[0001] The present invention relates to an impeller for a fan, e.g.
for a room fan or a built-in fan for cooling and/or air circulation
in an electrical appliance.
[0002] Particularly in the case of small-format high-speed fans,
vibrations of a drive motor, being transferred to the impeller of a
fan, can provoke a resonant frequency of the impeller. This results
in considerable operating noise of the fan, in addition to which
the vibration can lead to material fatigue of the impeller and to
its destruction in the course of time.
[0003] The object of the present invention is to specify an
impeller for a fan, which impeller is insensitive to possible
vibrations of a drive motor.
[0004] In the case of a fan impeller having a hub in which a
receptacle for a driving shaft is formed, and having a plurality of
vanes which are fastened to the hub, the object is achieved by
means of the hub having at least one elastic damping body that is
arranged between the receptacle and the vanes.
[0005] In order to damp the transfer of vibrations from the shaft
to the vanes, and as far as possible to prevent vibrations of the
vanes relative to each other, the vanes are preferably fastened to
a hub outer ring which is connected via the damping body to a hub
inner section having the receptacle.
[0006] According to a first specific embodiment, the damping body
can occupy an annular intermediate space between the outer ring and
the inner section.
[0007] Alternatively, it is also possible to arrange a plurality of
damping bodies, these being circumferentially distributed, in an
annular intermediate space between the outer ring and the inner
section.
[0008] The damping body preferably consists of a different material
than the outer ring and/or the inner section, in particular of a
material having high elasticity. In particular, this material can
be a silicone or a rubber.
[0009] However, an embodiment is also conceivable in which the
plurality of circumferentially distributed damping bodies are
embodied integrally with the outer ring and the inner section. In
this case, the required elasticity of the damping bodies can be
achieved by means of said damping bodies having a smaller wall
thickness than the outer ring or the inner section.
[0010] If the damping bodies are not embodied in one piece with the
ring or the inner section, it is advantageous for the ring and/or
the inner section to have recesses into which the damping bodies
engage positively, such that ring and inner section cannot be
rotated in opposite directions.
[0011] In order to ensure that the damping bodies are held firmly,
the recesses can be undercut.
[0012] The inner section preferably comprises a central sleeve,
which forms the receptacle, and an annular wall that runs annularly
around the sleeve at a distance. An annular spring surrounding the
slotted sleeve can therefore be introduced for the purpose of
fastening the impeller to a shaft.
[0013] The central sleeve and the annular wall can be connected in
one piece in order to simplify manufacture.
[0014] A connecting piece which connects the central sleeve to the
annular wall is preferably arranged at an end face of the hub. An
axially extending intermediate space can therefore be created
between the central sleeve and the annular wall, wherein said space
can comfortably accommodate an axially extending spring which acts
to fasten the hub to the shaft.
[0015] According to an alternative embodiment, an annular spring
can also surround the inner section, and the at least one damping
body is arranged in an annular intermediate space between the outer
ring and the inner section so as to be axially offset relative to
the spring.
[0016] The impeller is preferably used in a fan which is arranged
in a domestic appliance such as a refrigerator. It is thereby
possible to prevent an unpleasant noise level when the fan is
operating, particularly during a rest phase of the compressor.
[0017] Further features and advantages of the invention emerge from
the following description of exemplary embodiments with reference
to the appended figures, in which:
[0018] FIG. 1 shows a perspective sectional view of an impeller
according to the present invention;
[0019] FIG. 2 shows a radial section through the hub of an impeller
according to a second embodiment of the invention;
[0020] FIG. 3 shows a section, similar to that in FIG. 2, according
to a third embodiment;
[0021] FIG. 4 shows a section, similar to that in FIG. 2, according
to a fourth embodiment;
[0022] FIG. 5 shows a perspective sectional illustration of an
impeller according to a fifth embodiment.
[0023] The impeller shown in FIG. 1 has a hub 1 of essentially
cylindrical form, from whose outer circumference a plurality of
vanes 2 project. The number of vanes 2 is largely arbitrary, the
example illustrated here comprising four vanes 2, of which only two
are visible in the figure. These vanes 2 are integrally connected
to an outer ring 3 of the hub 1. A plurality of silicone damping
bodies 6 are arranged circumferentially at equal intervals in an
annular cavity 4 between the outer ring 3 and an inner section 5 of
the hub 1, said inner section 5 being arranged within said outer
ring 3. Of the four damping bodies here, three can be seen in the
figure, of which two in cross section. The damping bodies 6 are the
only frictional connection between the outer ring 3 and the inner
section 5.
[0024] The inner section 5 comprises an outer annular wall 7 and,
surrounded by this and concentric relative thereto, a sleeve 8
which is open in the direction of an end face of the hub 1, said
end face facing away from the observer, in order to accommodate a
shaft (not shown) of a drive motor. A slot 9, which is open towards
the end face facing towards the observer, extends transversely
through the sleeve 8. The annular wall 7 and the sleeve 8 are
connected in one piece at the end face facing away from the
observer by a radially oriented wall 10. The wall 10, the annular
wall 7 and the sleeve 8 respectively form the base and two side
walls of an annular groove 11, which is open in the direction of
the end face of the inner section 3, said end face facing towards
the observer, in order to accommodate a slotted annular tension
spring 12. As a result of the two halves of the sleeve 8 being
pressed together by the tension spring 12, a secure press fit is
achieved in respect of the impeller on the drive shaft that is
accommodated in the sleeve 8.
[0025] Any transfer of unevennesses (in the shaft movement) to the
outer ring 3 or the vanes 2 is damped by means of the damping
bodies 6. Because the damping bodies 6 damp any movement of the
annular wall 7 and the inner section 5 relative to each other, they
also suppress the development of sympathetic vibration of the vanes
2.
[0026] Depending on elasticity and damping ability of the damping
bodies 6, it can be effective to increase their number or their
circumferential extent until the extreme case as shown in FIG. 2
(in cross section along the line II indicated in FIG. 1) is
reached, in which the cavity 4 is completely occupied by a single
annular damping body 6.
[0027] In the embodiments shown in FIGS. 1 and 2, the friction
between the damping bodies 6 and the outer ring 3 or the inner
section 5 essentially prevents any lasting rotation of the ring 3
relative to the inner section 5. For this purpose, it is necessary
for the damping body 6 to be elastically deformed at all times, in
order to establish the required pressure against the ring 3 and the
inner section 5. This can prove problematic, particularly if the
fan is exposed to low temperatures (e.g. when used for circulating
cold air in a domestic refrigerator), since many of the
rubber-elastic materials that are suitable for the damping bodies 6
have an elasticity that decreases significantly at low
temperatures. Different thermal expansion coefficients of the
selected materials can also contribute to the marked temperature
dependency of the friction between the damping bodies 6 and the
ring 3 and/or the inner section 5.
[0028] In order to achieve a damped elastic while nonetheless
rotation-resistant coupling between the outer ring 3 and the inner
section 5, irrespective of the temperature, a further developed
embodiment makes provision for recesses into which the damping
bodies 6 engage on the opposing surfaces of the inner section 5 and
the ring 3. Particularly secure fixing of the damping bodies is
achieved if, as illustrated in a section in FIG. 3 which is similar
to that in FIG. 2, the recesses on the outer ring 3 and the inner
section 5, designated 13 and 14 respectively, are undercut and the
damping bodies 6, having an H-shaped cross section here, engage
positively in the undercuts of the recesses 13, 14. In this
embodiment, no pre-tensioning of the damping bodies 6 is required
in the balanced state, and therefore the damping bodies 6 can yield
slightly to a torque acting between the ring 3 and the inner
section 5. The more yielding the damping bodies 6, the lower the
resonance frequency of any rotational shearing of the ring 3 and
the inner section 5 relative to each other. By selecting this
resonance frequency such that it is sufficiently remote from any
frequency component of the motor movement, rotational shearing of
the ring 3 relative to the inner section 5 can be effectively
prevented or damped to a level that is not relevant in terms of
noise development.
[0029] A simplified modification is illustrated in FIG. 4. In this
case, the damping bodies 6 that are made of silicone and fixed to
the walls of the ring 3 and/or the inner section 5 are replaced by
narrow bridges 15, which are molded integrally with the ring 3 and
the inner section 5 and whose elasticity is derived from their
considerably thinner wall thickness in comparison with the outer
ring 3 and the inner section 5.
[0030] A further simplified embodiment is illustrated in FIG. 5 in
a view which is similar to that of FIG. 1. In this embodiment, the
annular wall 7 of the embodiments considered above is omitted and
the slotted sleeve 8 is connected in one piece to the outer ring 3
(which carries the vanes 2) via a radial wall 16 at the end face of
the hub 1, said end face facing towards the motor of the shaft. The
thickness of the wall 16 is clearly less than that of the wall 10
in the previously considered embodiments; it allows a vibration of
the outer ring 3 relative to the sleeve 8 along an axis which runs
transverse to the rotational axis of the hub 1. At the same time,
any such vibration is significantly damped by an annular damping
body 17 which is pressed into an annular groove 18 between the
sleeve 8 and the ring 3.
[0031] As explained with reference to FIG. 1, a tension spring 12
is axially pushed onto the sleeve 8 in order to clamp a shaft that
is accommodated in the sleeve 8. It is also possible to omit the
tension spring 12 and to apply the pressure to the sleeve 8 by
means of the pressed-in damping body 17 alone, said pressure being
required for the purpose of clamping the shaft.
* * * * *