[0001] The invention relates to a balancing ring for compensating imbalances of a spinning
machine rotor as well as a spinning machine rotor unit with a corresponding balancing
ring. Additionally, the invention relates to a method for compensating imbalances
of a spinning machine rotor unit.
[0002] Spinning rotors are widely used in spinning machines, in particular in open-end rotor
spinning machines. The output rotors connected to spinning boxes of open-end rotor
spinning machines spin with a high number of revolutions per minute. Accordingly,
even a small imbalance of the spinning rotor leads to large forces acting on the parts
of the spinning machine.
[0003] Document
DE 26 40 111 A1 discloses a rotor of an open-end spinning unit consisting of the spinning rotor as
well as a shaft attached thereto, a cylindrical rotor part connected coaxially to
the spinning rotor, and magnetized permanent magnets radially fixed on the inner wall
of the cylindrical rotor part. The magnets form a rotor drive together with windings
on a stator part, which is projecting into the rotor part. The magnets are fixed to
the rotor part by plastic webs, wherein at least a part of the plastic webs arranged
in parallel to the magnets comprises substantially axially extending channels for
receiving rod-shaped materials, in particular balancing weights, for balancing the
rotor.
[0004] It may be considered a first object of the present invention to propose a balancing
ring for compensating imbalances of a spinning machine rotor as well as a corresponding
spinning machine rotor to at least reduce imbalances and preferably to balance out
the spinning rotor completely.
[0005] A further objective of the invention may be to propose a balancing ring for compensating
imbalances of a spinning machine rotor with a simple mechanics and which therefore
can be easily and cost-efficiently produced.
[0006] It might be finally considered an objective of the present invention to propose a
balancing ring for compensating imbalances of a spinning machine rotor as well as
a method for compensating imbalances of a spinning machine rotor unit which is easily
executable and in particular which comprises a self-balancing of the spinning system
without any external controlling.
[0007] These and further objectives may be achieved by a balancing ring according to claim
1, a spinning machine rotor unit according to claim 9 or a method for compensating
imbalances of a spinning machine rotor unit according to claim 14. Dependent claims
refer to preferred embodiments of the invention.
[0008] A balancing ring for compensating imbalances of a spinning machine rotor according
to the invention comprises balance weight elements guided by a circular guidance body
as well as a supporting element for arranging the circular guidance body coaxially
to an axis of rotation of a spinning machine rotor, wherein the balance weight elements
are movable along the full circumference of the circular guidance body.
[0009] Further, the present invention relates to a spinning machine rotor unit with a balancing
ring according to the invention, wherein the balancing ring is mounted on a rotor
shaft between a drive motor and a spinning machine rotor.
[0010] The method for compensating imbalances of a spinning machine rotor unit of the present
invention comprises as a first step the mounting of at least one balancing ring on
a rotor shaft of a spinning machine rotor, followed by starting the spinning machine
rotor with a first rotation speed of the rotor shaft for self-balancing several balance
weight elements of the balancing ring, wherein this first speed is lower than a rotation
speed during regular operation of the spinning machine rotor. After the self-balancing
phase, the spinning machine rotor is accelerated to the regular operation speed of
rotation as a further step of the inventive method.
[0011] The inventors have recognized that arranging several objects with a given distance
to an axis of rotation in a spinning machine rotor unit and allowing the objects to
freely move along the circumference leads to a self-balancing system in view of initial
imbalances of the spinning machine rotor unit. The balancing ring according to the
invention uses this principle and therefore easily balances out a spinning machine
rotor leading to a smoother operation, less wear and longer operation times of the
corresponding spinning machine.
[0012] The inventors have further realized that a balancing ring according to the invention
does not require any external control and can be built with only very few components,
hence reducing the production costs and leading to a simple, jet effective system
which is less prone to errors than more complex and/or actively controlled systems.
[0013] A balancing ring according to the invention is any part or module which comprises
several balance weight elements movable along its full circumference, preferably at
a constant radius or distance to the center of the balancing ring and/or an opening
for mounting the balancing ring on a rotatable axle or shaft. The balancing ring might
be made out of any material, though metals and/or polymers are preferred. Even more
preferably, the balancing ring is only made out of one single material, wherein the
balance weight elements might be made from a different material.
[0014] The balancing ring is preferably especially built for a rotating axle or shaft of
a spinning machine for processing fiber material or roving into workable yarn or thread
and in particular for a motor shaft of an open-end spinning machine rotor. Such a
rotor might spin with over 100,000 revolutions per minute and even up to 200,000 revolutions
per minute during regular operation. Accordingly, even small imbalances would lead
to large forces action upon the rotating parts.
[0015] In the method according to the invention, the spinning machine rotor with the balancing
ring is initially started at a lower speed of rotation to allow the balance weight
elements to move to the required positions along the circumference of the circular
guidance body. The rotation might be started and quickly accelerated to a constant
speed of revolution which is lower than the speed of revolution during regular operation,
preferably between 5 % and 75 %, more preferably between 10 % and 60 % and most preferably
between 25 % and 50 % of the speed of rotation during regular operation. It is further
preferred that this constant, lower speed of rotation is maintained for several seconds,
in particular between 1 s and 3 s, to allow for the positioning of the balance weight
elements. Alternatively, the rotation might be started and accelerated, in particular
constantly accelerated, over a period of several seconds, preferably between 5 s and
60 s, more preferably between 10 s and 30 s.
[0016] The circular guidance body can have any shape as long as it can guide balance weight
elements along a circular path coaxially to an axis, in particular of rotation of
the spinning machine rotor. Accordingly, it is advantageous that the circular guidance
body has a shape of a ring and/or is arranged in a plane perpendicular to the axis
of rotation of the spinning machine rotor or a corresponding rotor shaft. The outer
surface of the circular guidance body might have any shape, although preferably the
circular guidance body and more preferably the whole balancing ring are built with
a rotational symmetry to its center and/or is shaped to be mostly free of imbalances
regarding the intended rotational axis of the balancing ring.
[0017] The circular guidance body has preferably an inner surface for directly guiding the
balance weight elements inside the circular guidance body and is more preferably adapted
to the shape of the balance weight elements so that each balance weight element can
freely move, most preferably roll on the inner surface of the circular guidance body
without a high rolling resistance.
[0018] The balancing ring may be a separate part or can be part of the rotor shaft or can
even be included in the spinning rotor. Accordingly, the supporting element may be
a part of the spinning rotor and/or the circular guidance body may be directly fixed
to or built as part of the spinning rotor or the rotor shaft. Preferably, the supporting
element has however no further function and/or is not part of the spinning rotor.
Even more preferably, the balancing ring including all its components is built as
an independent part which can be mounted to a spinning rotor or a rotor shaft.
[0019] The main function of the support element is to arrange the circular guidance body
at a constant distance and/or coaxially to an axis of rotation, which is preferably
positioned in the center of the opening of the balancing ring. Generally, the support
element might be made out of a single part or several separate parts. Further, the
support element might be built from any material. It is however preferred that the
support element is built from the same material as the circular guidance body and/or
is attached to or built as one piece with the circular guidance body. Advantageously,
also the support element is built with a rotational symmetry to its center to be mostly
free of rotational imbalances.
[0020] The balance weight elements may have any shape and may be made from any material.
Preferably, all balance weight elements have a spherical shape with an identical diameter
and/or weight. Further preferred, all balance weight elements have an identical weight
and most preferably all balance weight elements are completely identical to one another.
This advantageously allows not only a simple and cheap construction of the balancing
ring, but also an exact guidance of each of the balance weight elements by a single
circular guidance body. To ensure a precise positioning of the balance weight elements
in the circular guidance body of the balancing ring, the diameters of the balance
weight elements are preferably almost identical to the cross section of the circular
guidance body, possible slightly smaller to allow for a low-friction movement. To
ensure a high weight of the balance weight elements and at the same time to minimize
the wear which might impair the ability to freely move within the circular guidance
body, all balance weight elements are preferably made out of metal.
[0021] According to an advantageous embodiment of the balancing ring, at least three balance
weight elements, preferably precisely three balance weight elements are arranged inside
the circular guidance body so that on the one hand a reliable compensation of imbalances
is possible, but on the other hand the balance ring is still easy to produce and has
a reasonably low weight. Albeit it would be theoretically possible to place significantly
more balance weight elements inside the circular guidance body, it is preferred that
only less than half as many balance weight elements as tightly fit, more preferably
less than 10 and most preferably between 3 and 6 balance weight elements are arranged
in one circular guidance body.
[0022] In a preferred further developed version of the balancing ring, the balance weight
elements are arranged in a closed volume inside of the circular guidance body which
is further preferred filled with a liquid having a high viscosity, in particular of
at least 50 mPas. Building the circular guidance body with a closed inner volume ensures
that the balance weight elements cannot roll out and further minimizes external effects
on the movement and positioning of the balance weight elements. Further, filling the
space surrounding the balance weight elements with viscous liquid leads to a further
stabilisation and/or damping of fast movements like vibrations. Most preferably the
space surrounding the balance weight elements is completely filled with liquid and
is in particular free of any gas. A high viscosity liquid has at least a viscosity
of 10 mPas, preferably of at least 50 mPas and in particular of at least 100 mPas.
Although the liquid may have any chemical composition, the liquid is preferably homogeneous
and is in particular an oil.
[0023] A further embodiment of the balancing ring is favoured where a disk with an opening
in the center for mounting the balancing ring on a rotor shaft of a spinning machine
rotor unit is attached in the middle of the circular guidance body as the supporting
element wherein the disk is most preferably a solid disk with a constant thickness.
Such an embodiment allows a simple construction of the balancing ring with a high
stability. Alternatively, the disk may have further openings and may for example be
constructed as a spoke wheel. The opening has preferably the shape of the cross section
of the rotor shaft to avoid any play between the balancing ring and the rotor shaft
during operation.
[0024] To avoid introducing further imbalance to the spinning machine rotor, an advantageous
embodiment of the balancing ring has a rotationally symmetrical shape in relation
to an axis of rotation, in particular the axis of rotation around a rotor shaft of
a spinning machine rotor unit.
[0025] It is further preferred that the circular guidance body as well as the disk are constructed
integrally as one piece or built by several pieces which have been inseparably combined,
for example by gluing. The construction of the circular guidance body as well as the
disk as a monobloc part allows a particularly cheap construction of the balancing
ring as well as a high stability against forces during high speed of rotation.
[0026] According to an advantageous embodiment of the balancing ring the outer diameter
of the circular guidance body is between 5 and 15 times the diameter of the balance
weight elements and/or of the width of the closed volume inside the circular guidance
body. In other words, the ratio between the radius of the circular guidance body from
the middle of the balancing ring and the radius of the spherical balance weight elements
is also between 5 and 15. This advantageously leads to large enough forces due to
the distribution of the balance weight elements over the circumference of the balancing
ring to compensate imbalances, in which case the distribution along the circumference
is uneven. Only if the spinning machine rotor unit is already in perfect balance,
the distance between all balance weight elements is exactly the same along the circumference
during operation of the spinning machine.
[0027] A spinning machine rotor unit may have a single or several balancing rings, in particular
all placed on one rotor shaft. For static balancing purposes only one single balancing
ring may be mounted on the rotor shaft, preferably placed in a spinning rotor groove
area. Under static balancing the balancing in one direction is understood, in particular
to avoid imbalances only in a plane perpendicular to the axis of rotation, i.e., if
one side of the rotor is heavier than the side exact opposite relative to the axis
of rotation. In other words, in a static imbalance the axis of rotation and the axis
through the center of mass of the rotating object are parallel, but not identical.
[0028] However, a preferred embodiment of the spinning machine rotor unit can also compensate
a dynamic imbalance. Therefore, in such an embodiment, at least a second balancing
ring is arranged on the rotor shaft preferably on an opposing side of the rotor shaft
bearing than the first balancing ring and most preferably precisely two balancing
rings are arranged on the rotor shaft. Accordingly, also imbalances in two spacial
directions can be compensated, i.e., where the axis of imbalance is not parallel to
the axis of rotation of the body. This is for example the case where on one end of
the rotor axis the mass is higher on one side of the axis in radial direction and
on the other end of the rotor axis the mass is higher on the opposite side in radial
direction. Accordingly, utilizing two balancing rings also the compensation of complex
imbalances is possible and a particularly smooth operation of a spinning machine rotor
unit can be achieved.
[0029] A preferred embodiment of a spinning machine rotor unit is built as an open-end spinning
machine rotor mounted on one end of the rotor shaft and the drive motor is connected
to the other end of the rotor shaft. Further, a rotor shaft bearing is arranged between
the spinning machine rotor and the drive motor and the at least first balancing ring
is arranged between the drive motor and the rotor shaft bearing, therefore compensation
the imbalances of the spinning machine unit close to the rotor shaft bearing and on
the opposite side of the spinning machine rotor. By placing the balancing ring in
this position, with only a single balancing ring most imbalances in the spinning machine
rotor unit can already be compensated.
[0030] Finally, it is further preferred that the balancing ring is fixed to the rotor shaft
by clearance fitting allowing a simple installation and replacement of the balancing
ring. Accordingly, the opening of the balancing ring is preferably adapted to the
size and shape of the rotor shaft.
[0031] These and other aspects of the invention will be apparent from and elucidated with
reference to an embodiment described hereinafter:
- Fig. 1
- shows a schematic side view of a spinning machine rotor unit with a balancing ring;
- Fig. 2
- shows a sectional view of the balancing ring of the spinning machine rotor unit of
figure 1,
- Fig. 3
- shows a perspective view of the balancing ring of the spinning machine rotor unit
of figure 1, and
- Fig. 4
- shows a perspective view of a spinning machine rotor unit with a balancing ring in
a cutaway view to show balance weight elements inside the balancing ring.
[0032] A spinning machine rotor unit 10 shown in figure 1 comprises a motor 11 driving a
rotor shaft 9 as well as a spinning machine rotor 2 connected to the rotor shaft 9
at an end opposing the motor 11. Directly adjacent to the motor 11, a balancing ring
1 is arranged on the rotor shaft 9. Additionally, a rotor shaft bearing 12 is positioned
on the rotor shaft 9 between the spinning machine rotor 2 and the balancing ring 1
to mount the rotor shaft 9 to a spinning machine.
[0033] The balancing ring 1 comprises a supporting element 5 built by a solid disk 7 having
an opening 8 in the center for mounting on the rotor shaft 9. The diameter of the
opening 8 is slightly larger than the diameter of the rotor shaft 9.
[0034] At the outer rim of the disk 7, a circular guidance body 3 is formed by a tube along
the whole circumference of the disc 7. The tube fully encloses a closed inner volume
6 of the circular guidance body 3 without any openings or gaps. The balancing ring
1 including the disk 7 and the circular guidance body 3 is built as one piece (see
fig. 2 and 3). The closed volume 6 inside the circular guidance body 3 has a circular
cross-sectional area. In the closed volume 6, three metal balls are arranged as balance
weight elements 4. All three balance weight elements 4 are identical to one another
and in particular have the same diameter and weight. All balance weight elements 4
are guided inside the closed volume 6 by the circular guidance body 3 to be able to
roll into any position along the circumference of the balancing ring 1 (see fig. 1
and 4).
[0035] To compensate imbalances in a spinning rotor unit, in particular due to a slight
asymmetry of an open-end spinning machine rotor, at least one balancing ring 1 is
placed on the rotor shaft 9 of the spinning machine rotor unit 10. The opening 8 in
the center of the balancing ring 1 centers the balancing ring 1 on the rotor shaft
9. When starting the spinning machine rotor unit 10, the rotor shaft 9 is first started
slowly and rotated by the drive motor 11 with a low speed of rotation compared to
the regular operation speed of the spinning machine. In the first few second, the
three balance weight elements 4 spread around the circumference of the balancing ring
1 inside the closed volume 6 of the circular guidance body 3 automatically compensating
imbalances.
[0036] If the spinning machine rotor unit 10 was already in perfect balance, the three balance
weight elements 4 are positioned every 120° along the circumference of the balancing
ring 1. However, if there is an initial imbalance, the balance weight elements 4 shift
to the side opposite to the higher weight of the spinning machine rotor 2 and therefore
automatically compensate imbalances. After the initial few seconds, typically 2 -
3 seconds, the rotor shaft 9 including the spinning machine rotor 2 is accelerated
to full operation speed of rotation and the balance weight elements 4 maintain their
positions in the balancing ring 1 further on compensating the imbalances in the spinning
machine rotor unit 10.
[0037] In the claims, any reference signs shall not be construed as limiting the claims.
The word "comprising" does generally not exclude the presence of elements or steps
other than those listed. The indefinite article "a" or "an" preceding an element does
not exclude the presence of a plurality of such elements. The mere fact that certain
measures are recited in mutually different dependent claims does not indicate that
a combination of these measures cannot be used to advantage.
List of reference signs
[0038]
- 1
- balancing ring
- 2
- spinning machine rotor
- 3
- circular guidance body
- 4
- balance weight element
- 5
- supporting element
- 6
- closed volume of the circular guidance body
- 7
- disk
- 8
- opening
- 9
- rotor shaft
- 10
- spinning machine rotor unit
- 11
- drive motor
- 12
- rotor shaft bearing
- D
- outer diameter of the circular guidance body
- d
- diameter of the balance weight elements
- c
- cross section of the closed volume
1. Balancing ring (1) for compensating imbalances of a spinning machine rotor (2), with
- balance weight elements (4) guided by a circular guidance body (3) and
- a supporting element (5) for arranging the circular guidance body (3) coaxially
to an axis of rotation of a spinning machine rotor (2),
characterized in that
- the balance weight elements (4) are movable along the full circumference of the
circular guidance body (3).
2. Balancing ring (1) according to claim 1, wherein all balance weight elements (4) have
a spherical shape with an identical diameter and/or weight.
3. Balancing ring (1) according to one of the above claims, wherein at least three balance
weight elements (4) are arranged inside the circular guidance body (3).
4. Balancing ring (1) according to one of the above claims, wherein the balance weight
elements (4) are arranged in a closed volume (6) inside of the circular guidance body
(3) which is filled with a liquid having a viscosity of at least 50 mPas.
5. Balancing ring (1) according to one of the above claims, wherein a disk (7) with an
opening (8) in the center for mounting the balancing ring (1) on a rotor shaft (9)
of a spinning machine rotor unit (10) is attached in the middle of the circular guidance
body (3).
6. Balancing ring (1) according to one of the above claims, wherein the balancing ring
(1) has a rotationally symmetrical shape in relation to an axis of rotation.
7. Balancing ring (1) according to one of the claims 5 or 6, wherein the circular guidance
body (3) as well as the disk (7) are constructed integrally as one piece.
8. Balancing ring (1) according to one of the above claims, wherein the outer diameter
(D) of the circular guidance body (3) is between 5 and 15 times the diameter (d) of
the balance weight elements (4) and/or of the cross section (c) of the closed volume
(6) inside the circular guidance body (3).
9. Spinning machine rotor unit (10) with a balancing ring (1) according to one of the
above claims mounted on a rotor shaft (9) between a drive motor (11) and a spinning
machine rotor (2).
10. Spinning machine rotor (2) unit according to claim 9, wherein for static balancing
purposes only one single balancing ring (1) is mounted on the rotor shaft (9).
11. Spinning machine rotor (2) unit according to claim 9 or 10, wherein the spinning machine
rotor (2) is mounted as an open-end spinning machine rotor on one end and the drive
motor (11) is connected to the other end of the rotor shaft (9), wherein a rotor shaft
bearing (12) is arranged between the spinning machine rotor (2) and the drive motor
(11) and the balancing ring (1) is arranged between the drive motor (11) and the rotor
shaft bearing (12).
12. Spinning machine rotor unit according to one of the claims 9 - 11, wherein the balancing
ring (1) is fixed to the rotor shaft (9) by clearance fitting.
13. Spinning machine rotor unit according to one of the claims 9 - 12, wherein at least
a second balancing ring is arranged on the rotor shaft (9) on an opposing side of
the rotor shaft bearing (12) than the first balancing ring (1).
14. Method for compensating imbalances of a spinning machine rotor unit (10), with the
steps:
- mounting at least one balancing ring (1), in particular according to one of the
above claims, on a rotor shaft (9) of a spinning machine rotor (2),
- starting the spinning machine rotor (2) with a first rotation speed of the rotor
shaft (9) lower than a rotation speed during regular operation of the spinning machine
rotor (2) for self-balancing several balance weight elements (4) of the balancing
ring (1), and
- accelerating the spinning machine rotor (2) to the regular operation speed.