Field of the invention
The present invention relates to the field of stator winding machines,
and precisely it relates to a method for guiding the wire on multi-pole stators
that can be wound by a flier-type machine.
The invention relates furthermore to a device that carries out this
Background of the invention
Multi-pole stators are known that can be wound by a flier-type machine,
having a stack of sheets substantially star-shaped forming a plurality of poles
that extend starting from a tubular core. The stators of this type fit either
with an inner armature or with a concentric outer ring-shaped armature. They are
very common in brushless motors and generators.
The adjacent boundaries of the poles define substantially a cylinder
with a plurality of longitudinal or oblique slits.
The boundaries of the poles are connected to the core by means of
branches that, between one another, define a plurality of grooves. Such grooves
have to be filled of wire by coils wound about the branches. At winding the wire
must pass beyond necessarily through the slits for reaching the grooves, and has
to be guided to avoid hitting against the edges of the slits.
Winding machines are known capable of winding the wire in the grooves
of the stator poles. They provide a winding arm, or flier, which rotates causing
the wire to follow a circular trajectory thus laying the coil about each pole.
The wire follows the circular trajectory while it is guided in the slits at the
sides of each pole by means of shrouds having round profile, normally of two types:
- a couple of lateral guiding plates, which define substantially a funnel that
guides the wire in the slits; collisions are thus avoided of the wire against the
edges of the adjacent poles to the pole that is being wound;
- a shroud that allows the wire to pass beyond around the pole making substantially
a double chute guide that moves the wire away from its own circular trajectory
and brings it to wind about the pole branch; the shroud normally is movable towards/away
from the axis of the stator for laying uniformly the wire along the pole branch.
The two types of shrouds are normally sufficient to wind most of
the common types of multi-pole stators that can be wound by a flier-type machine.
The shroud can be in one or in two parts. In the first case, it has
a central opening in which the pole can enter. This is used when the width of the
pole is similar to that of the winding and the slits are wide enough to allow
its passage. In the second case, the shroud comprises two halves that are closed
after having passed the slits at the end of the approaching movement. Also in
this case, the width of the pole is similar to that of the winding but the slits
are as narrow as possible, for improving the performances of the motor.
However, many stators of this type, studied mostly for efficiency
reasons than for a easy winding, they are wound with difficulty, owing to the shape
of the slot and to the dimension of the pole. For example, in the stators of large
diameter the poles may be very wide, which extends far beyond the portion of groove
to fill with the coil.
Therefore, the drawbacks are a not uniform filling of the slot or
the risk of hits of the wire against the pole, with impossibility to obtain a complete
In many cases, moreover, winding is geometrically impossible with
the shrouds of known art. To overcome this drawback, the stator is split into many
parts, assembling eventually the boundary of the stator only after winding. This,
however, has the drawback of a more expensive and complicated production process.
Summary of the invention
It is therefore object of the present invention to provide a method
for guiding the wire on multi-pole stators that avoids splitting the stator even
if allowing a most favourable filling of the slot and an uniform distribution
of the wire.
It is particular object of the invention to provide such a method
- the movement of the shroud is not limited, to avoid that the wire can collide
with the pole and can move for laying the wire along all the pole branch;
- in case of stators of large diameter and with large grooves to fill, the wire
can easy pass beyond the pole boundary for entering the grooves.
Therefore, according to the invention, a method for guiding the wire
on multi-pole stators that can be wound by a flier-type machine,
wherein the stators have a core from which a plurality of branches
radially extend defining grooves and having pole boundaries, said pole boundaries
having longitudinal edges, which define slits for reaching the grooves and circumferential
edges that define the height of the stator,
and wherein the wire is wound about said branches by means of
a rotatable arm guided by first fixed shrouds, which define substantially a funnel
to avoid hits of the wire against the longitudinal edges of adjacent poles, and
second shrouds, which define a couple of chute guides that pass beyond the circumferential
edges of the pole and move radially for laying the wire along the branches,
provides the approaching of third shrouds against the boundary
of the pole that guide at winding the wire to avoid hits of the wire against the
longitudinal edges of the pole same.
Preferably, the third shrouds and the second shrouds
- in a first step they approach integrally the stator,
- in a second step, at winding, they are movable relative to each other, the
third shrouds remaining fixed against the stator and the second shrouds reciprocating
for laying the wire about one pole;
- in a third step move away integrally from the stator.
Advantageously, the third shrouds and the second shrouds are movable
relative to each other urged by an elastic force.
According to another aspect of the invention, in a stator winding
machine of the above type,
comprising a rotatable arm suitable for winding the wire about
said branches, first fixed shrouds that define a funnel to avoid hits of the wire
against the longitudinal edges of adjacent poles, and second shrouds that define
a couple of chute guides that pass beyond the circumferential edges of the pole
and that move radially for laying the wire along the branches,
third shrouds are provided that approach the boundary of the
pole from outside at winding and guide the wire to avoid hits of the wire against
the longitudinal edges of the pole same.
Preferably, the third shrouds are slidingly mounted with respect
to a support of said second shrouds whereby the approaching of said shrouds towards
said pole causes the contact of said third shrouds with the pole same at their
lateral edges, and the further radial movement of said shrouds towards the axis
of the stator is allowed by the relative reciprocation of said third shrouds with
respect to said support.
Brief description of the drawings
Further characteristics and the advantages of the method and of the
device according to the invention for guiding the wire on multi-pole stators will
be made clearer with the following description of an embodiment thereof, exemplifying
but not limitative, with reference to the attached drawings, wherein:
Description of a preferred embodiment
- figures 1 and 2 are respectively a top plan and an elevation side view of a
step for guiding the wire on a multi-pole stator according to the prior art, comprising
a shroud mobile;
- figures 3 and 4 are respectively a top plan and an elevation side view of a
step of pre-winding according to the invention of a multi-pole stator, comprising
a mobile shroud to which a shield is associated for covering the pole;
- figures 5 and 6 are respectively a top plan and an elevation side view of a
winding step following the step of figures 3 and 4.
With reference to figures from 1 to 4, according to the prior art,
a stator 1 that can be wound by a flier-type machine is formed by a substantially
star-shaped stack of sheets 2, from which a plurality of poles 4 extend starting
from a tubular core 3. The boundaries of poles 4, form together substantially a
cylinder with a plurality of longitudinal grooves 5. The pole boundaries are connected
to the core by means of branches 6 about which coils 7 are wound.
A winding machine, not shown, comprises a flier, which is also not
shown, that rotates laying the wire 8 about the pole branch 6, and creating thus
a coil 7 on each pole. For guiding the wire 8 at the sides of each pole 4 on which
is being wound, shroud device 10 is provided having a couple of lateral guiding
plates 11, which define substantially a funnel that guides the wire in the grooves
5. Collisions are thus avoided of the wire against the edges of poles 4a and 4b
adjacent to the pole 4 that is being wound.
In the solution of figures 1 and 2, the device 10 comprises a shroud
12 that allows the wire 8 to overcome the pole 4, defining substantially a upper
and lower chute guide that moves the wire 8 away from its own circular trajectory
and brings it to wind about the pole branch 6. Shroud 12 normally is movable towards/away
from the axis of the stator, up to the position indicated with dashed line, for
laying uniformly the wire along the pole branch. To avoid any collision with the
pole 4 of the stator, it has a centre front opening, not shown, in which the pole
4 enters. This type of shroud 12 is suitable for pole boundaries 4 of dimension
not very larger than the size of the coil, and that that do not have too small
In the solution of prior art of figures 3 and 4, instead, shroud
12 has shroud halves 12' that can approach each other by means of a cam 15, which
pushes against outer rollers 14 integral to shrouds 12', biasing a spring 13.
The shroud halves 12' are mounted slidingly on a support 16 by means of a slide
17 that engages with a guide 18. This type of shroud with shroud halves 12' is
suitable for pole boundaries 4 of size not very larger than the size of the coil
and that define other slits smaller than the previous case.
With reference to figures 5 and 6, for a geometry of stators 1 similar
to that of figures from 1 to 4, but with different geometry, a shielding device
20 is provided according to the invention. Its feature is that the movement of
shrouds 12" does not cause the collision of wire 8 with pole 4, with the consequence
that the shrouds 12" can freely move and lay the wire about all the pole branch
According to the invention, at winding, against the boundary of the
pole 4 third shrouds 21 do approach, that guide the wire 8 to avoid hits of the
wire against the longitudinal edges of the pole same.
More precisely, the third shrouds 21 are slidingly mounted with respect
to the support 16 by means of guiding rods 22 biased by a spring 23. Third shrouds
21 are connected to each other by a transversal plate 24.
As shown in figures 3 and 4, starting from the position indicated
with a dashed line, the integral approaching movement of device 20 towards pole
4 being wound ends with the contact between third shrouds 21 and pole 4 same,
at the longitudinal edges thereof. Then, with reference to figures 7 and 8, the
further radial movement of the support 16 towards the axis of stator 1 is allowed
by the relative movement of the guiding rods 22 with respect to support 16, biased
by spring 23.
This way, the shrouds 12" can move radially without that wire 8 collides
against the pole 4, assured by the presence of third shrouds 21.
The new solution above presented has the advantage to allow winding
many types of stators having special geometry, which differ from the typology shown
in figures from 1 to 4, and whose winding is not possible with the known systems.
Concerning the opening movement of shrouds 12'' biased by spring
13, for laying more layers of wire 8 and forming the coils 7, it is similar to
that shown in figure 3, by means of cam 15, and then not shown in detail. Obviously,
in association to the inventive concept of the presence of third shrouds 21 and
of the relative movement with respect to shroud halves 12'', the movement of opening/closure
of the shrouds can be made in any desired other way.
The foregoing description of a specific embodiment will so fully
reveal the invention according to the conceptual point of view, so that others,
by applying current knowledge, will be able to modify and/or adapt for various
applications such an embodiment without further research and without parting from
the invention, and it is therefore to be understood that such adaptations and
modifications will have to be considered as equivalent to the specific embodiment.
The means and the materials to realise the different functions described herein
could have a different nature without, for this reason, departing from the field
of the invention. It is to be understood that the phraseology or terminology employed
herein is for the purpose of description and not of limitation.