U.S. patent application number 15/734809 was filed with the patent office on 2021-07-29 for fan comprising a cooling body consisting of heat-conductive plastic.
The applicant listed for this patent is ebm-papst Mulfingen GmbH & Co. KG. Invention is credited to Daniel GEBERT, Thomas HELI, Peter RIEGLER, Valerius SCHAAF.
Application Number | 20210231125 15/734809 |
Document ID | / |
Family ID | 1000005533985 |
Filed Date | 2021-07-29 |
United States Patent
Application |
20210231125 |
Kind Code |
A1 |
HELI; Thomas ; et
al. |
July 29, 2021 |
FAN COMPRISING A COOLING BODY CONSISTING OF HEAT-CONDUCTIVE
PLASTIC
Abstract
The invention relates to a fan (1) comprising an electronic
system on a printed circuit board (2) and a cover (10) arranged
above the electronic system, which is embodied both as an active
cooling body and a passive cooling body, wherein the cover (10) is
designed substantially as a flat covering element consisting of a
thin-walled plastic and has a form with a surface (11) which is
effective for the cooling of the electronic system arranged beneath
the cover (10), said surface being larger than the projected base
area of the cover (10) by a factor of at least 2.
Inventors: |
HELI; Thomas; (Langenburg,
DE) ; RIEGLER; Peter; (Boxberg, DE) ; GEBERT;
Daniel; (Oehringen, DE) ; SCHAAF; Valerius;
(Kupferzell, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ebm-papst Mulfingen GmbH & Co. KG |
Mulfingen |
|
DE |
|
|
Family ID: |
1000005533985 |
Appl. No.: |
15/734809 |
Filed: |
July 25, 2019 |
PCT Filed: |
July 25, 2019 |
PCT NO: |
PCT/EP2019/070049 |
371 Date: |
December 3, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04D 29/023 20130101;
F04D 29/4226 20130101; F04D 29/5813 20130101; F04D 25/068
20130101 |
International
Class: |
F04D 25/06 20060101
F04D025/06; F04D 29/02 20060101 F04D029/02; F04D 29/58 20060101
F04D029/58; F04D 29/42 20060101 F04D029/42 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 3, 2018 |
DE |
10 2018 118 925.7 |
Claims
1. A fan (1), comprising an electronic system on a printed circuit
board (2) and a cover (10) arranged above the electronic system,
which is embodied both as an active cooling body and a passive
cooling body, wherein the cover (10) is designed substantially as a
flat covering element consisting of a thin-walled plastic and has a
form with a surface (11) which is effective for the cooling of the
electronic system arranged beneath the cover (10), said surface
being larger than the projected base area of the cover (10) by a
factor of at least
2. The fan (1) according to claim 1, characterized in that the
cover (10) has a cooling fin structure with a plurality of cooling
fins (12).
3. The fan (1) according to claim 1, characterized in that the
cover (10) forms a plurality of recesses (13) in which fastening
holes (14) are provided at which the cover (20) is detachably
fastened to the fan (1) by releasable fastening means (15).
4. The fan (1) according to claim 2, characterized in that the
cover (10), in the area of the cooling fin structure, has a flat
contact side (16) for contacting heat-producing components.
5. The fan (1) according to claim 2, characterized in that the
cover (10) has the cooling fin structure in one or more areas.
6. The fan (1) according to claim 2, characterized in that the
cooling fins (12) are attached or formed to extend radially
outwards.
7. The fan (1) according to claim 2, characterized in that the
cooling fins (12) have a changing, in particular outwardly
decreasing, wall thickness.
8. The fan (1) according to claim 1, characterized in that the
cover (10) forms a flat contact surface (19) on the bottom facing
the electronic system, and in that, in the assembled state, this
contact surface at least partially abuts electronic components.
9. The fan (1) according to claim 1, characterized in that the
cover (10) is formed from a substantially round section (17)
integrally joined to a projection (18).
10. The fan (1) according to claim 1, characterized in that the
material of the cover (10) is a polyamide (PA), polyurethane (PUR),
polycarbonate (PC) or polyethylene (PE).
11. The fan (1) according to claim 8, characterized in that the
thickness of the cover (10) is smaller in the area parallel to the
arrangement of the printed circuit board (2) and/or the area of the
flat contact surface (19) than in a periphery (20) or in the area
of the cover (10) extending towards the electronic system by a
factor of at least 2.
12. The fan (1) according to claim 1, characterized in that the fan
is a radial fan.
Description
[0001] The invention relates to a fan comprising a cooling body
embodied as a plastic cover.
[0002] A cooling body has the task of absorbing heat from an
element to be cooled and releasing it again to a surrounding
medium. As such, a material of high thermal conductivity, such as
aluminum or copper, is typically used for the cooling body.
[0003] Mass production of aluminum cooling bodies, in particular
those whose form is adapted to a predetermined application, is
typically done using the die casting process. For this purpose,
heated aluminum in the liquid or sticky state is pressed, under
high pressure, into a preheated steel mold which will later serve
as a conductive cooling body.
[0004] Cooling bodies are also used for motors. For example, DE
19841583 A1 addresses a cooling body for cooling elements, in
particular semiconductor components, motors and aggregates, in
particular a cooling unit at least partially made of extruded
aluminum or other light metal, consisting of at least two separate
base profiles for mounting the electric components which are spaced
apart from each other and interconnected by means of a plurality of
separate cooling fins. Further, the assembly of at least one fan is
provided between two adjacent base profiles.
[0005] It is convenient to utilize heat conduction for cooling. In
physics, heat conduction--also known as heat diffusion or thermal
conduction--is understood to mean the flow of heat induced by a
difference in temperature. As such, according to the second law of
thermodynamics, heat always only flows in the direction of the
lower temperature, i.e., in the direction of the temperature sink.
Heat conduction is a mechanism for transferring thermal energy
without requiring a macroscopic flow of material as with the
alternative mechanism of convection. Heat transfer through heat
radiation is also considered as a separate mechanism. A measure of
heat conduction in a particular substance is thermal
conductivity.
[0006] It is therefore obvious that, for utilizing cooling by means
of a cooling body, a substance or material of good to very good
thermal conductivity is used. Copper and its alloys typically have
thermal conductivity values of 100-400 W/mK: with 236 W/mK,
aluminum is also within a range of high thermal conductivity. As a
metal material, even unalloyed steel already has a significantly
poorer heat conduction property and exhibits a thermal conductivity
in the range of about 50 W/mK.
[0007] Industrial plastics, such as PUR or polyimide (PA), are
known in the art to be unsuitable as heat conductors due to their
significantly lower conductivity of not even 1/1000 of the value of
copper. Thus, copper provides a conductivity which is better than
that of conventional plastics by more than 1000 times.
[0008] In the case of fans and fan motors with an integrated
electronic system, the electronic system naturally becomes warm or
hot and must therefore be cooled to avoid damage to the electronic
system and increase its lifetime. While typical metallic covers
dissipate heat well, they are expensive to manufacture and not
achievable in a cost-effective manner due to the high material
price alone.
[0009] The object of the invention is therefore to provide cooling
for the electronic system of a fan motor of a fan, which can be
produced cost-effectively and works reliably.
[0010] This object is achieved by the combination of features
according to claim 1.
[0011] A basic idea of the present invention is to cool the
electronic system of a fan using a plastic cooling body instead of
a metal cooling body. This approach, which is unknown in the prior
art, can be realized by using the cooling body as a cover with a
very thin wall thickness having a specific form and surface.
[0012] In addition to increasing the surface area, several effects
are used in a targeted and cumulative manner, namely heat
conduction, heat convection and the reduction of heat build-up, by
using a thin-walled plastic material having a large efficient
surface and a comparatively large proportion with a direct contact
surface for heat-producing components.
[0013] In this way, in a departure from the prior art, a cover
enabling the resulting heat to be thermally dissipated can also be
obtained with a plastic material in a cheap and efficient
manner.
[0014] According to the invention, for this purpose, a fan is
provided, comprising an electronic system on a printed circuit
board, wherein, above the electronic system, a cover is provided
which works both as an active cooling body and a passive cooling
body, wherein, for this purpose, the cover is designed
substantially as a flat covering element consisting of a
thin-walled plastic and has a form with a surface effective for the
cooling of the electronic system arranged beneath the cover, said
surface being larger than the projected base area of the cover by a
factor of at least 2.
[0015] For this purpose, it is particularly advantageous if the
cover has a cooling fin structure with a plurality of cooling fins
which increase the effective surface.
[0016] It is further advantageous if the cover forms a plurality of
recesses in which fastening holes are provided at which the cover
is detachably fastened to the fan by releasable fastening
means.
[0017] It is further advantageously provided that the cover has, in
the area of the cooling fin structure, a flat contact side for
directly contacting heat-producing components.
[0018] In a further advantageous embodiment of the invention it is
provided that the cover has the cooling fin structure in one or
more areas or forms a plurality of areas with such a cooling fin
structure.
[0019] Furthermore, it is advantageous if the cooling fins are
attached or formed to extend radially outwards, thereby
implementing a structure open radially outwards and upwards which
has an advantageous effect on production and the cooling
effect.
[0020] A further improvement can be achieved in that the cooling
fins have a changing, in particular outwardly decreasing, wall
thickness. Other forms and configurations of the wall thickness are
also conceivable to improve heat dissipation effects. In principle,
contrary to the metal bodies with large wall thicknesses usually
used in the prior art, according to the concept of the present
invention, an overall smaller wall thickness is aimed for in order
to achieve rapid heat dissipation and also to prevent heat
build-up.
[0021] A further optimization is a solution in which the cover
forms a flat contact surface on the bottom facing the electronic
system and in which, in the assembled state, this contact surface
at least partially abuts electronic components.
[0022] In an advantageous embodiment of the invention for a radial
fan, the cover is formed from a substantially round section
integrally joined to a projection (preferably with a linearly
extending lateral edge).
[0023] It has also been shown to be advantageous if the material of
the cover is a polyimide (PA), polyurethane (PUR), polycarbonate
(PC) or polyethylene (PE).
[0024] In a further advantageous embodiment, it is provided that
the thickness of the cover is smaller in the area parallel to the
arrangement of the printed circuit board and/or the area of the
flat contact surface than in a periphery or in the area of the
cover extending towards the electronic system by a factor of at
least 2. As a result, the essential stabilizing properties can be
placed in the periphery and the essential thermal properties in the
flat area and the areas with the cooling fins.
[0025] Other advantageous developments of the invention are
characterized in the sub-claims or are shown in more detail below
together with the description of the preferred embodiment of the
invention with reference to the figures.
[0026] Therein:
[0027] FIG. 1 shows a schematic sectional view through a radial
fan,
[0028] FIG. 2 shows a perspective view of the radial fan of FIG.
1,
[0029] FIG. 3 shows a top view of the cover of the electronic
system of the radial fan of FIG. 1,
[0030] FIG. 4 shows a perspective view of the cover of FIG. 3,
[0031] FIG. 5 shows a sectional view of the cover of FIG. 3.
[0032] In the following, the invention will be explained in greater
detail on the basis of an exemplary embodiment with reference to
FIGS. 1 to 5, in which the same reference numerals indicate the
same structural and/or functional features.
[0033] FIG. 1 shows a schematic sectional view through a fan 1,
here a radial fan.
[0034] Fan 1 is embodied with an electronic system on a printed
circuit board 2. Above the electronic system, a cover 10 according
to the invention is shown which is embodied both as an active
cooling body and a passive cooling body. As such, as can be seen in
FIGS. 3 to 5, cover 10 is designed as a substantially flat covering
element consisting of a thin-walled plastic and has a form with a
surface 11 which is effective for the cooling of the electronic
system arranged beneath cover 10, said surface being larger than
the projected base area of cover 10 by a factor of at least 2 due
to the cooling fin structure with a plurality of cooling fins 12 as
can be seen in FIG. 2. As can also be seen, the cooling fins run or
extend radially outwards.
[0035] The projected base area can be seen in the top view from the
illustration in FIG. 3. As can also be seen in FIG. 5, the
effective active surface is significantly increased by the fin
structure. Cover 10 is formed from a substantially central round
section 17 integrally joined to a projection 18 with a straight
lateral edge.
[0036] In FIGS. 3 and 4, it can be seen that cover 10 forms a
plurality of recesses 13 in which fastening holes 14 are
provided.
[0037] Operatively connected to the electronic system, cover 20 is
detachably fastened to fan 1 by releasable fastening means 15
(e.g., screws). On the bottom facing the electronic system, cover
10 forms a flat contact surface 19 by which it at least partially
abuts electronic components in the assembled state.
[0038] In the sectional view through cover 10, as shown in FIG. 5,
it has a flat contact side 16 for contacting heat-producing
components of the electronic system in the area of the cooling fin
structure. It can also be seen that cooling fins 12 have a changing
wall thickness, in particular slightly decreasing from bottom to
top, and taper slightly, so to speak.
[0039] The practice of the invention is not limited to the
preferred exemplary embodiments specified above. Rather, it is
conceivable, to adapt the form and configuration of the cover
correspondingly to the respective requirement and, for example, the
number of areas with fin structures to the specific cooling
task.
* * * * *