Title of Invention

ELECTRICAL MACHINE WITH A SEALED CASING

Abstract The invention relates to an electrical machine (1) comprising a casing (2) in which there is a stator and a rotor (3) mounted on a shaft (4), the casing (2) comprising a cup-shaped part (5) and a lid (6) connected to one another with removable connecting devices, and a static seal (7) inserted between the cup-shaped part (5) and the lid (6), the seal (7)being an O-ring seal positioned in a seat (10) in the lid (6) or the cup-shaped part (5) and also comprising retaining means (8) so that it remains applied to one of the elements, either the lid (6) or the cup-shaped part (5); the electrical machine being characterised in that the seal (7) retaining means (8) are rings (11) each ring (11) being connected to the seal (7) by two sections (12).
Full Text Description
Technical Field
The present invention relates to an electric motor for
electric fans having a casing with at least a lid with a
hermetic seal and a method for assembly of the motor.
In particular, the present invention relates to a casing for an
electric motor comprising at least a lid and a housing, having
an intermediate wO-ring" type seal with characteristics which
facilitate assembly.
The present invention also relates to a method for assembly
of the casing of an electric motor characterised by facilitated
assembly steps.
The following description refers to an electric motor, but
it must be considered that the present invention may also be
applied to an electric generator, for example an alternator or a
dynamo.
Background Art
Generally speaking, an electric machine such as an
electric motor or a dynamo comprises a stator, a rotor mounted
on a shaft and a casing which has supports for the rotor shaft.
To mount the stator and the rotor in the casing, the casing
must be separated into at least two parts which can be put
together.
An example of an electric machine and of a method for its
production is known from US patent 5 767 596.
Electric motors that are water- and humidity-proof are also
known, especially in the sector of electric fans for motor
vehicles.
Due to the environmental conditions and the position of
electric fans close to heat sources and/or cold sources, the

humidity in the environment may penetrate the motor
casing and following temperature variations it may be
transformed into liquids, creating electrical problems for
the motor.
Starting with the typical construction of the motor
casing in two parts, of which one part is cup-shaped and the
other part is lid-shaped, attempts were made to produce a
waterproof casing for electric motors, inserting a seal
between the above-mentioned two parts.
However, this type of assembly is not without
disadvantages: indeed, the insertion of a seal complicates
the structure of the motor.
In addition, for motor casing sealing to be effective,
the seal must be correctly positioned between the two parts,
which must also have suitable housings for the seal.
Disclosure of the Invention
One aim of the present invention is to provide an
electric motor for an electric fan having a casing of an
improved type with good water- and humidity-proof
characteristics.
Another aim of the present invention is to provide an
electric motor for an electric fan having a casing which is
simple and economical to produce and assemble.
According to one aspect of it, the present invention
provides an electrical machine comprising an electrical
machine comprising a casing in which there is a stator
and a rotor mounted on a shaft, the casing comprising a
cup-shaped part and a lid connected to one another with
removable connecting devices, and a static seal inserted
between the cup-shaped part and the lid the seal being an
O-ring seal positioned in a seat in the lid or the cup-
shaped part and also comprising retaining means so that
it remains applied to one of the elements, either the lid
or the cup-shaped part; the electrical machine being
characterised in that the seal retaining means are rings

each ring being connected to the seal by two sections.
Another aim of the present invention is to provide a
method for assembly of an electric motor including a step of
connecting a seal to one of the parts of the motor casing so
as to facilitate assembly of the motor.
Preferred, advantageous embodiments of the invention are
described hereinafter.
Brief Description of the Drawings
The accompanying drawings illustrate embodiments of the

present invention without limiting the scope of its application,
and in which:
Figure 1 is a perspective exploded view of the electric
motor according to the present invention; and
Figure 2 is a detail of the electric motor illustrated in
Figure 1.
Description of a Preferred Embodiment of the Invention
With reference to the accompanying drawings, the electric
motor 1 basically comprises a casing 2 in which there is a stator
(not illustrated) and a rotor 3 mounted on a shaft 4.
The following description refers to an electric motor, but
it must be considered that the present invention may also relate
to other types of similar electric machines, for example current
generators such as alternators.
The casing 2 in turn comprises a cup-shaped part 5 and a
lid 6 connected to one another by connecting devices of the
known type and therefore not illustrated in detail.
To create a good seal against liquids and humidity, a
static seal 7 is inserted between the cup-shaped part 5 and the
lid 6.
The static seal 7 may be any type of elastic seal which,
when inserted between the cup-shaped part 5 and the lid 6 is
subject to slight compression by the respective surfaces
operating in conjunction with one another between the two parts
5, 6 of the casing 2 and so provides a seal against external
agents (liquids, dust, etc.).
The seal 7 also comprises retaining means 8 which allow
the seal 7 to be applied to and held on one of the two parts 5,
6 of the casing 2.
For this purpose, the part 5, 6 in question also has fixing
means 9 which operate in conjunction with the retaining means 8
to temporarily make the seal 7 integral with one of the two
parts 5, 6.
In the embodiment illustrated, the seal 7 is an O-ring
seal, made of an elastomeric material, or the like, operating
frontally between the cup-shaped part 5 and the lid 6 and

inserted in a seat 10 made in the lid 6.
As is known, Oaring type seals, when operating frontally,
are slightly compressed, causing the seal to expand sideways.
Therefore, the seal seat must be wide enough to allow this
expansion.
The retaining means 8 comprise at least two retaining rings
11 with diameter smaller than the diameter of the seal 7. The
retaining rings 11 are connected to the seal 7 by short
connecting sections 12 and are positioned at regular intervals
along the circumference.
The retaining rings 11 hold the seal 7 extended and
adhering in the seat 10 and it is important that the rings 11
are not too close to one another, to prevent them from
interfering with the normal seal 7 deformations.
The rings 11 are preferably integral with the seal 7 and
are made of the same elastomeric material as the seal.
The rings 11 are on the outer side of the O-ring seal and
are close to the outer edge of the casing 2. In the embodiment
illustrated in the accompanying drawings, the rings 11 are
close to the connecting devices for the cup-shaped part 5 and
the lid 6. Therefore, the latter respectively have protrusions
13, 14 in which the connecting devices, the seats for the rings
11 and the fixing means 9 are located.
In the embodiment illustrated in the accompanying drawings
the retaining rings 11 are four devices set at 90 degrees to one
another and each ring 11 is connected to the O-ring seal by two
connecting sections 12.
The latter, together with each ring 11, are made with a
smaller diameter wd", or are thinner than, the diameter or
thickness "D" of the seal 7, so that they do not interfere with
seal 7 compression and therefore with its effective sealing.
Each ring 11 is inserted about a fixing pin 15 which
constitutes the fixing means 9 and is on the lid 6 in the
protrusions 14. Obviously, the seat 10 for the O-ring seal and
the fixing pins 15 for the rings 11 may alternatively be on the
cup-shaped part 5 in the protrusions 13.
The fixing pin 15 may have a diameter slightly larger than

that of the ring 11 internal hole, the ring remaining attached
to the pin 15 partly thanks to the elasticity of the material
the ring 11 is made of.
The fixing pin 15 may also be made with a truncated cone
profile, or it may have a shallow circumferential cavity (not
illustrated).
Whatever the case, the ring 11, elastically deforming on
the fixing pin 15, remains attached to the fixing pin and as a
result the entire O-ring seal is held in the seat 10.
The method for assembly of the casing of an electric motor
disclosed comprises the steps of inserting the O-ring seal in
the seat 10 in the lid 6 or in the cup-shaped part 5, and
inserting each retaining ring 11 on each fixing pin 15 in the
lid 6 or in the cup-shaped part 5, so that the seal 7 remains
positioned in the seat 10 applied to one of the elements,
either the lid 6 or the cup-shaped part 5. Then the components
3 inside the casing 2 can be fitted and the lid 6 can be
connected to the cup-shaped part 5.
The present invention brings important advantages.
Thanks to the retaining means 8 on the seal 7, the latter
can easily be applied to the lid 6 or to the cup-shaped part 5,
making assembly of the motor 1 simpler.
The retaining means 8 in the form of rings 11 on the O-ring
seal and the fixing pins 15 on the lid 6 or on the cup-shaped
part 5 are simple to produce and effectively secure the O-ring
seal.
Even the costs for production of the retaining means 8 are
contained thanks to the simplicity of the components.
The invention described can be subject to modifications and
variations without thereby departing from the scope of the
inventive concept, as defined in the claims herein.
Moreover, all the details of the invention may be
substituted by technically equivalent elements.

LIST OF REFERENCE CHARACTERS
1 electric motor
2 casing
3 rotor
4 rotor 3 shaft
5 cup-shaped part
6 lid
7 seal
8 retaining means
9 fixing means
10 seal 7 seat
11 retaining rings
12 connecting sections between rings 11 and seal 7
13, 14 protrusions on elements 5, 6
15 fixing pin
d diameter or thickness of the retaining rings 11 and
sections 12-
D diameter or thickness of the seal 7.

We Claim:
1. An electrical machine (1) comprising a casing (2) in which there is a
stator and a rotor (3) mounted on a shaft (4), the casing (2) comprising a
cup-shaped part (5) and a lid (6) connected to one another with removable
connecting devices, and a static seal (7) inserted between the cup-shaped
part (5) and the lid (6), the seal (7)being an O-ring seal positioned in a seat
(10) in the lid (6) or in the cup-shaped part (5), and also comprising
retaining means (8) so that it remains applied to one of the elements, either
the lid (6) or the cup-shaped part (5);
the electrical machine being the seal (7) retaining means (8) are rings
(11) each ring (11) being connected to the seal (7) by two sections (12).
2. The electrical machine (1) as claimed in claim 1, wherein the seal (7)
retaining means (8) operate in conjunction with fixing means (9) present in
the lid (6) or in the cup-shaped part (5).
3. The electrical machine (1) as claimed in claim 2, wherein the fixing
means (9) are pins (15) which have a diameter slightly larger than that of the
ring (11) internal hole, so that the ring adheres to the pin (15) thanks to the
elasticity of the material used to make the ring (11).
4. The electrical machine (1) as claimed in claim 2, wherein the fixing
means (9) are pins (15) which have a truncated cone profile or a
circumferential cavity with a diameter slightly larger than that of the ring
(11) internal hole, so that the ring adheres to the pin (15) thanks to the
elasticity of the material used to make the ring (11).
5. The electrical machine (1) as claimed in claim 2, wherein the rings
(11) are close to the devices connecting the cup-shaped part (5) and the lid

(11) are close to the devices connecting the cup-shaped part (5) and the lid
(6), the latter respectively having protrusions (13, 14) in which the
connecting devices, the rings (11) and the pins (15) are located.
6. The electrical machine (1) as claimed in any of the preceding claims,
wherein the rings (11) are integral with the seal (7) and are made of the same
elastomeric material.
7. The electrical machine (1) as claimed in any of the preceding claims,
wherein the rings (11) the sections (12) are made with a diameter (d) smaller
than, or are thinner than, the diameter or the thickness (D) of the seal 7, so
that they do not interfere with seal 7 compression.

Documents:

00431-kolnp-2006-abstract.pdf

00431-kolnp-2006-claims.pdf

00431-kolnp-2006-description complete.pdf

00431-kolnp-2006-drawings.pdf

00431-kolnp-2006-form-1.pdf

00431-kolnp-2006-form-3.pdf

00431-kolnp-2006-form-5.pdf

00431-kolnp-2006-international publication.pdf

00431-kolnp-2006-international search authority.pdf

00431-kolnp-2006-pct forms.pdf

00431-kolnp-2006-priority document.pdf

431-kolnp-2006-assignment.pdf

431-KOLNP-2006-CORRESPONDENCE 1.1.pdf

431-KOLNP-2006-CORRESPONDENCE 1.2.pdf

431-KOLNP-2006-CORRESPONDENCE-1.1.pdf

431-KOLNP-2006-CORRESPONDENCE.pdf

431-kolnp-2006-correspondence1.3.pdf

431-kolnp-2006-examination report.pdf

431-kolnp-2006-form 18.pdf

431-kolnp-2006-form 3.pdf

431-kolnp-2006-form 5.pdf

431-KOLNP-2006-FORM-27.pdf

431-kolnp-2006-gpa.pdf

431-kolnp-2006-granted-abstract.pdf

431-kolnp-2006-granted-claims.pdf

431-kolnp-2006-granted-description (complete).pdf

431-kolnp-2006-granted-drawings.pdf

431-kolnp-2006-granted-form 1.pdf

431-kolnp-2006-granted-form 2.pdf

431-kolnp-2006-granted-specification.pdf

431-KOLNP-2006-OTHERS PATENT DOCUMENTS.pdf

431-KOLNP-2006-OTHERS-1.1.pdf

431-KOLNP-2006-OTHERS.pdf

431-kolnp-2006-others1.2.pdf

431-KOLNP-2006-REPLY TO EXAMINATION REPORT.pdf

431-kolnp-2006-reply to examination report1.1.pdf

abstract-00431-kolnp-2006.jpg


Patent Number 248891
Indian Patent Application Number 431/KOLNP/2006
PG Journal Number 36/2011
Publication Date 09-Sep-2011
Grant Date 06-Sep-2011
Date of Filing 24-Feb-2006
Name of Patentee SPAL AUTOMOTIVE S.R.L.
Applicant Address VIA PER CARPI, 26/B, I-42015 CORREGGIO ITALY
Inventors:
# Inventor's Name Inventor's Address
1 SPAGGIARI, ALESSANDRO VIA LEONARDO DA VINCI, 8 I-42015 CORREGGIO, ITALY
PCT International Classification Number H02K 5/10
PCT International Application Number PCT/IB2004/003186
PCT International Filing date 2004-09-28
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 BO2003A000563 2003-09-30 Italy