Title of Invention

DEVICE FOR TRANSMITTING THE MOVEMENT TO A FAN FOR COOLING THE COOLANT IN A MOTOR VEHICLE

Abstract A device for transmitting the movement to a fan (1) for cooling the coolant in a motor vehicle is disclosed. The device comprises a fixed support shaft (13), movement generating means (3) and actuating means (20) comprising a coaxial sleeve (21); a first electromagnetic clutch (30); a second electromagnetic clutch (60); means (62) of the electromagnetic type for engaging/disengaging the said second clutch, the armature (33) of the first clutch (30) and the support bell (la) of the fan (1) are mounted on a support bearing (33a) keyed onto said movement generating sleeve (21), characterized in that said engaging means (62) of the second electromagnetic clutch (60) comprise a permanent magnet (62a) and a coil (62b) with controlled excitation, said magnet (62a) and coil (62b) are mounted on said sleeve (21) in a position axially different from the position of the rotor (61) and with the arrangement of a bearing (70) in between, the armature (66) of the second clutch is linked to the rotating sleeve (21) .
Full Text The present invention relates to a device for
transmitting the movement to fans for cooling the
coolant in motor vehicles.
It is known in the technical sector relating to the
cooling of coolants contained in motor-vehicle
radiators that there exists the need to force air onto
the radiator in order to obtain more rapid dissipation
of heat from the coolant to the exterior, said forced
air flow being obtained by causing rotation of a fan
which is normally mounted either directly on the
driving shaft or on the water pump shaft or on a driven
and fixed shaft carrying a pulley which receives
movement from a belt actuated by the driving shaft.
It is also known that said fan must be made to rotate
only upon reaching a certain predefined temperature of
the water detected by means of a thermostat which
activates an electromagnetic clutch, closing of which
causes the fan to start rotating.
More particularly it is required that a motor vehicle
fan must be able to rotate:
- at a lower speed than that of the transmission shaft
for cooling in low external temperature conditions;
- at a speed equal to or even greater than that of the
transmission shaft in the case of higher external
temperatures or use in severe conditions which cause
overheating of the engine;
- at zero speed, namely with the fan which does not
rotate at all and remains in an idle condition with
respect to the transmission shaft, in the case of
particularly low temperatures at which further cooling
is of no use or even damaging.
In an attempt to achieve these performance features,
coupling systems of the mixed type with
electromagnetically operated friction clutches and
drive couplings based on the use of parasitic currents
generated by rotation of a conducting element in the
vicinity of permanent magnets have been developed.
DE-32 03 143 describes, for example, an arrangement in
which the driving shaft is connected to the rotor of an
electromagnetic clutch, which is engaged by an armature
connected to the fan for direct driving, whereas low
speed conditions make use of the engagement between a
conducting disk, rotating with the transmission shaft,
and the permanent magnets integral with the fan, said
engagement causing transmission of movement at a low
speed as a result of relative slipping between the two
parts. With this solution, however, it is not possible
to obtain the idle condition of the fan.
In order to overcome this drawback, EP-1,130,232, in
the name of the same present Applicants, described a
device for transmitting the movement to a fan for
cooling the coolant in a motor vehicle, comprising
movement generating means on which the fan is mounted
by means of an idle support, a first electromagnet
clutch, engagement/disengagement of which causes a
rotation of the fan at a number of revolutions equal to
that of the movement generating means or at zero speed;
a second clutch, engagement/disengagement of which
causes a rotation of the fan at a number of revolutions
less than or at zero speed compared to that of the
movement generating means; means of the electromagnet
type for engagement/disengagement of the said second
clutch, in which said first clutch is supported in a
position substantially adjacent to the fixed base of
the engine casing and said second clutch is supported
by a shaft fixed in a position substantially projecting
with respect to the base of the engine.
Although fulfilling its function, this device, however,
has drawbacks arising from the fact that the small air
gap present between the rotor of the second clutch and
the fixed electromagnet may result in abnormal wear in
the event of accidental contact due either to the
vibrations transmitted by the movement generating part
integral with the internal-combustion engine or to the
tolerances as regards the concentricity of the coaxial
parts in relative movement.
In addition, the known device does not envisage the
possibility of maintaining an albeit slow rotation of
the fan in the case of breakage and/or complete
interruption of the power supply to the coils of the
clutches as occurs for example in the case of total
electrical failure.
The technical problem which is posed, therefore, is
that of providing a device for transmitting the
rotational movement to a fan for cooling the coolant of
motor vehicles, which allows the fan to rotate at a
number of revolutions which can be determined depending
on the actual cooling requirement of the engine,
including also the possibility of keeping the fan
stationary in an idle position, which has compact
dimensions and does not have large and costly
projecting rotational masses, which is formed by a
small number of costly parts and which is able to
ensure reliable rotation of the fan also in the case of
malfunction of the power supply and control devices.
Accordingly, the present invention provides a device for
transmitting the movement to a fan for cooling the coolant in
a motor vehicle, comprising a fixed support shaft and
movement generating means and actuating means
comprising a coaxial sleeve, connected to the movement
generating means, on which the fan is mounted by means of an
idle support;
- a first electromagnetic clutch, the rotor of which is
integral with said movement generating means and engagement of
which causes rotation of the fan at a number of revolutions
equal to that of the movement generating means;
- a second electromagnetic clutch, the rotor of which is
mounted on said sleeve and engagement/disengagement of which
causes rotation of the fan at a lower number of revolutions or
zero speed compared to that of the movement generating means;
means of the electromagnetic type for engaging/
disengaging the said second clutch,
in which said first clutch is supported in a position
substantially adjacent to the fixed base of the engine casing
and said second clutch is supported by a coaxial sleeve in a
position substantially projecting from the base of the engine,
- the armature of the first clutch and the support bell
of the fan are mounted on a support bearing keyed onto said
movement generating sleeve
characterized in that said engaging means of the second
electromagnetic clutch comprise a permanent magnet and a coil
with controlled excitation,
said magnet and coil are mounted on said sleeve in a
position axially different from the position of the rotor and
with the arrangement of a bearing in between, the armature of
the second clutch is linked to the rotating sleeve.
Further details may be obtained from the following
description of a non-limiting example of embodiment of
the invention, provided with reference to the
accompanying drawings in which:
Figure 1 shows a schematic axial section through the
device for transmitting the movement to the fan
according to the present invention.
As shown in Fig. 1, the device for transmitting the
movement to a cooling fan 1 for moor vehicles is
arranged between the fan 1 itself and actuating means
20 integral with a pulley 3 connected to the driving
shaft by means of a belt (not shown) . For the sake of
convenience of the description below, "longitudinal
direction" will be understood as meaning that direction
coinciding with/parallel to the longitudinal axis of
the actuating means 20.
In greater detail the actuating means comprise a hollow
sleeve 21, one end of which is connected to a rotor 31
integral with the pulley 3 and mounted on a bearing 11
keyed onto a seat 12a of a fixed support flange 12
integral with the base 10 of the engine.
Said flange 12 has a longitudinal extension towards the
exterior, which forms a fixed spindle 13 with an inner
through-cavity 13a through which electrical wires 67
may be passed.
Said rotor 31 forms the rotating element of a first
clutch 30 formed by an annular electromagnet 32
concentric with the rotor 31 and arranged between the
latter and the fixed flange 12 and electrically
connected to a thermostat (not shown) for example for
the cooling-water temperature.
The armature 33 of the clutch 30 is arranged on the
opposite side to the electromagnet 32 with respect to
the rotor 31 and is connected to the thrust piece of a
bearing 33a in turn keyed onto the hollow sleeve 21, a
bell la which supports the fan 1 also being coupled to
the said thrust piece.
On the free end of the hollow sleeve 21 there is
mounted a second clutch 60 of the induction type which
is based on Foucault currents or parasitic currents and
engagement of which is obtained by associated means
consisting of a second annular electromagnet 62 in turn
coaxially mounted on the hollow sleeve 21 by means of a
bearing 70 arranged between and concentrically inserted
in a special annular seat 61a of the rotor 61 of the
second clutch 60.
Said rotor 61 is in turn mounted on an associated
bearing 61b keyed onto the sleeve 21.
The armature 63 of the second clutch is arranged on the
opposite side to the rotor 61 with respect to the
electromagnet 62 and is locked in rotation with the
sleeve 21 by means of an elastic membrane 66 able to
allow the displacement of the armature in the axial
direction, but not its rotation about the longitudinal
axis.
The electromagnet 62 is of the type with a permanent
magnet 62a which constantly attracts the armature 63
until the controlled energisation of the coil 62b
neutralizes the magnetic field of the magnet 62a.
As mentioned, the second clutch 60 is of the induction
type based on parasitic or Foucault currents and
comprises a plurality of permanent magnets 65 which are
supported by a retaining ring 65a made of non-magnetic
material and integral with the bell la, and a ring 64a
made of conductive material and forming an annular part
of the rotor 61 on which a non-magnetic element 64b,
for example made of aluminium, is integrally cast.
In this way the ring 65a and the magnets 65 form the
induction linkage elements with the annular part 64a of
the rotor for causing rotation of the bell la and
therefore the fan 1.
The operating principle of the coupling is as follows:
- if both the electromagnet 32 and the coil 62b of the
second clutch 60 are kept deactivated, the armature 33
of the first clutch 30 remains separated from the rotor
31, while the armature 63 of second clutch 60, recalled
by the magnet 62a, engages with the rotor 61 which,
starting to rotate, causes linkage of the second clutch
60 with the bell la and the consequent rotation of the
fan 1; said rotation produces the formation of
parasitic induction currents between the elements 64a
and 65a of the clutch 60 which causes rotation of the
bell la and therefore the fan 1.
Since driving of the bell by means of the rotor 61
occurs with relative slipping, the fan will rotate at a
speed lower than that of the sleeve 21.
- if the electromagnet 32 of the first clutch 30 is
activated, the armature 33 is recalled into contact
with the rotor 31, together with which it starts to
rotate, causing the rotation of the bell la, and
therefore the fan 1, at a number of rotations equal to
that of the actuating pulley 3;
- if the coil 62b of the second clutch is excited,
deactivating the electromagnet 32 of the first clutch
30, both the armatures 33 and 63 of the respective
clutches remain detached from the associated rotor
31/61 and consequently the bell la and therefore the
fan 1 remain stationary in the idle condition with
respect to the sleeve 21 generating the movement.
In the event of total failure or interruption in the
electric power supplying the electromagnets 32 and 62,
the magnet 62a of the second clutch attracts the
armature 63, causing movement of the rotor 61 which, by
means of the clutch 64, maintains an albeit minimum
rotation of the fan (so-called "Fail Safe" effect),
allowing the vehicle to be driven without assistance to
a service centre.
It is therefore pointed out how the transmission device
according to the invention is able to produce the three
required rotational speeds of the fan (number of
revolutions equal to/less than/zero compared to the
movement generating shaft) as well as a slow safety
rotation without large rotating loads projecting on the
fixed support, since the electromagnet of the second
clutch may have much smaller dimensions and ensure
improved safety conditions since any defects in the
concentricity and/vibrations transmitted by the
internal-combustion engine would not have any effect on
the correct rotation of the rotor of the second clutch.
In other words, the fact of arranging all the rotating
parts on the movement generating sleeve ensures the
concentricity of the various parts which are all
equally subject to the same stresses.
Although not shown, it is envisaged that the device
according to the invention may be designed with a
second clutch of the magnetic hysteresis type instead
of the induction type.
In this case the permanent magnets supported by a ring
are arranged on the rotor of the second clutch, while a
ring of magnetically semi-hard material is coupled to
the bell la.
The operating principle of the device remains
substantially unchanged.
In the preferred embodiment shown in Fig. 1, it is.
envisaged moreover that:
- the membrane 66 of the armature 63 of the second
clutch 60 is directly coupled to the rotating sleeve
21;
- the armature 33 of the first clutch 30 is directly
fixed to the associated bearing 33a;
- the connection between the magnet 62a of the second
clutch and the fixed spindle 13 is performed by means
of a non-rigid element 71, such as rubber or the like.
WE "CLAIM :
1. Device for transmitting the movement to a fan (1) for
cooling the coolant in a motor vehicle, comprising a fixed
support shaft (13) and
- movement generating means (3) and actuating means (20)
comprising a coaxial sleeve (21), connected to the movement
generating means (3), on which the fan (1) is mounted by means
of an idle support (la);
- a first electromagnetic clutch (30), the rotor of which
is integral with said movement generating means (3) and
engagement of which causes rotation of the fan (1) at a number
of revolutions equal to that of the movement generating means;
- a second electromagnetic clutch (60), the rotor (61) of
which is mounted on said sleeve (21) and engagement/
disengagement of which causes rotation of the fan at a lower
number of revolutions or zero speed compared to that of the
movement generating means (3);
- means (62) of the electromagnetic type for engaging/
disengaging the said second clutch,
in which said first clutch (30) is supported in a
position substantially adjacent to the fixed base (10) of the
engine casing and said second clutch (60) is supported by a
coaxial sleeve (21) in a position substantially projecting
from the base (10) of the engine,
- the armature (33) of the first clutch (30) and the
support bell (la) of the fan (1) are mounted on a support
bearing (33a) keyed onto said movement generating sleeve (21)
characterized in that said engaging means (62) of the
second electromagnetic clutch (60) comprise a permanent magnet
(62a) and a coil (62b) with controlled excitation,
said magnet (62a) and coil (62b) are mounted on said
sleeve (21) in a position axially different from the position
of the rotor (61) and with the arrangement of a bearing (70)
in between, the armature (66) of the second clutch is linked
to the rotating sleeve (21).
2. Device as claimed in claim 1, wherein said first clutch
(30) and second clutch (60) are arranged coaxially with a
fixed support shaft (13) and with each other.
3. Device as claimed in claim 1, wherein the support of the
magnet (62) is coupled to the fixed support shaft (13) via
elastic means (71).
4. Device as claimed in claim 1, wherein the rotor (61) of
the second clutch (60) is mounted on the movement generating
sleeve (21) via a bearing (61b).
5. Device as claimed in claim 1, wherein the conducting
element of the second clutch (60) consists of an armature (63)
integral with the movement generating means (21).
6. Device as claimed in claim 6, wherein said armature (63)
is arranged on the opposite side to the rotor (61) with
respect to the electromagnet (62), said armature being locked
in rotation with the movement generating means (21) by means
of an elastic membrane (66).
7. Device as claimed in claim 1, wherein the rotor (61) of
the second clutch (60) has a circumferential flange (64a) on
which an annular element (64b) made of non-magnetic material
is integrally cast.
8. Device as claimed in claim 1, wherein said second clutch
(60) is of the parasitic-current type.
9. Device as claimed in claim 1, wherein said second clutch
(60) is of the magnetic-hysteresis type.
10. Device as claimed in claim 1, wherein said fixed support
spindle (13) is located coaxially inside the movement
generating means (21) which are in turn located coaxially
inside the second clutch (60).
11. Device as claimed in claim 1, wherein said fixed shaft
(13) has a coaxial through-cavity (13a).
12. Device as claimed in claim 11, wherein the electric wares
for convection to the electromagnet of the second engaging
clutch are arranged inside said coaxial through-cavity (13a)
of the fixed shaft (13).


A device for transmitting the movement to a fan (1) for
cooling the coolant in a motor vehicle is disclosed. The
device comprises a fixed support shaft (13), movement
generating means (3) and actuating means (20) comprising a
coaxial sleeve (21); a first electromagnetic clutch (30); a
second electromagnetic clutch (60); means (62) of the
electromagnetic type for engaging/disengaging the said second
clutch, the armature (33) of the first clutch (30) and the
support bell (la) of the fan (1) are mounted on a support
bearing (33a) keyed onto said movement generating sleeve (21),
characterized in that said engaging means (62) of the second
electromagnetic clutch (60) comprise a permanent magnet (62a)
and a coil (62b) with controlled excitation, said magnet (62a)
and coil (62b) are mounted on said sleeve (21) in a position
axially different from the position of the rotor (61) and with
the arrangement of a bearing (70) in between, the armature
(66) of the second clutch is linked to the rotating sleeve
(21) .

Documents:

0839-kol-2005-abstract.pdf

0839-kol-2005-claims.pdf

0839-kol-2005-description complete.pdf

0839-kol-2005-drawings.pdf

0839-kol-2005-form-1.pdf

0839-kol-2005-form-2.pdf

0839-kol-2005-form-3.pdf

0839-kol-2005-form-5.pdf

839-KOL-2005-ABSTRACT 1.1.pdf

839-kol-2005-abstract.pdf

839-KOL-2005-AMANDED CLAIMS.pdf

839-KOL-2005-AMANDED PAGES OF SPECIFICATION.pdf

839-KOL-2005-ASSIGNMENT.1.3.pdf

839-kol-2005-assignment.pdf

839-KOL-2005-CANCELLED PAGES.pdf

839-kol-2005-claims.pdf

839-KOL-2005-CORRESPONDENCE 1.1.pdf

839-KOL-2005-CORRESPONDENCE 1.2.pdf

839-KOL-2005-CORRESPONDENCE.1.3.pdf

839-kol-2005-correspondence.pdf

839-KOL-2005-DESCRIPTION (COMPLETE) 1.1.pdf

839-kol-2005-description (complete).pdf

839-KOL-2005-DRAWINGS 1.1.pdf

839-kol-2005-drawings.pdf

839-KOL-2005-EXAMINATION REPORT.1.3.pdf

839-KOL-2005-FORM 1.1.1.pdf

839-kol-2005-form 1.pdf

839-KOL-2005-FORM 18.1.3.pdf

839-kol-2005-form 18.pdf

839-KOL-2005-FORM 2.1.1.pdf

839-kol-2005-form 2.pdf

839-KOL-2005-FORM 3.1.3.pdf

839-KOL-2005-FORM 3.1.pdf

839-kol-2005-form 3.pdf

839-KOL-2005-FORM 5.1.1.pdf

839-KOL-2005-FORM 5.1.3.pdf

839-kol-2005-form 5.pdf

839-KOL-2005-GPA.1.3.pdf

839-kol-2005-gpa.pdf

839-KOL-2005-GRANTED-ABSTRACT.pdf

839-KOL-2005-GRANTED-CLAIMS.pdf

839-KOL-2005-GRANTED-DESCRIPTION (COMPLETE).pdf

839-KOL-2005-GRANTED-DRAWINGS.pdf

839-KOL-2005-GRANTED-FORM 1.pdf

839-KOL-2005-GRANTED-FORM 2.pdf

839-KOL-2005-GRANTED-LETTER PATENT.pdf

839-KOL-2005-GRANTED-SPECIFICATION.pdf

839-KOL-2005-OTHERS 1.1.pdf

839-KOL-2005-OTHERS 1.2.pdf

839-kol-2005-others.pdf

839-kol-2005-priority document.pdf

839-KOL-2005-REPLY TO EXAMINATION REPORT.1.3.pdf

839-KOL-2005-REPLY TO EXAMINATION REPORT.pdf

839-kol-2005-specification.pdf

839-KOL-2005-TRANSLATED COPY OF PRIORITY DOCUMENT.1.3.pdf


Patent Number 247738
Indian Patent Application Number 839/KOL/2005
PG Journal Number 19/2011
Publication Date 13-May-2011
Grant Date 10-May-2011
Date of Filing 12-Sep-2005
Name of Patentee BARUFFALDI S. P. A.
Applicant Address VIA CESARE BATTISTI, 6 SAN DONATO, MILANESE (MI)
Inventors:
# Inventor's Name Inventor's Address
1 BOFFELLI PIERCARLO VIA PIETRO MASCAGNI, 20 MILANO
PCT International Classification Number F01P7/08,7/04,
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 MI2004A001813 2004-09-22 Italy