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Title:
DEVICE FOR ATTACHING BALANCING WEIGHTS TO A ROTOR
Document Type and Number:
WIPO Patent Application WO/2019/197799
Kind Code:
A1
Abstract:
A device for attaching one or more balancing weights to a rotor, the rotor including first and second sets of projections, the first set of projections being positioned in a first balancing plane and the second set of projections being positioned in a second balancing plane, with the first and second balancing plane being spaced from each other along an axis of the rotor, wherein each projection is provided for supporting, where necessary, a balancing weight, wherein the device includes: a first engaging member for engaging with either a portion of the rotor at or near the first set of projections, or for engaging with one of the projections of the first set of projections, which projection supports or holds at least one balancing weight; a second engaging member for engaging with one of the projections of the second set of projections, which projection supports or holds at least one balancing weight; a first movement mechanism for effecting relative movement between the first and second engaging members; and a controller for controlling the first movement mechanism so as to cause the first or second engaging member to engage the projection supporting or holding the at least one balancing weight and impart a force to said projection, which force is sufficient enough to deform said projection so as to attach the balancing weight to the rotor and prevent or at least inhibit the balancing weight from being able to be removed from the projection.

Inventors:
FOWLER, Steve (12 Douglas Road, Kingswood Bristol BS15 8PD, BS15 8PD, GB)
Application Number:
GB2019/050903
Publication Date:
October 17, 2019
Filing Date:
March 28, 2019
Export Citation:
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Assignee:
UNIVERSAL BALANCING LIMITED (12 Douglas Road, Kingswood Bristol BS15 8PD, BS15 8PD, GB)
International Classes:
H02K15/16; G01M1/04; G01M1/32; H02K7/04
Foreign References:
US5282309A1994-02-01
JPS5972036A1984-04-23
JPH0326266U1991-03-18
CN104753277A2015-07-01
Attorney, Agent or Firm:
Forresters IP LLP (Rutland House, 148 Edmund Street, Birmingham West Midlands B3 2JA, B3 2JA, GB)
Download PDF:
Claims:
CLAIMS

1. A device for attaching one or more balancing weights to a rotor, the rotor including first and second sets of projections, the first set of projections being positioned in a first balancing plane and the second set of projections being positioned in a second balancing plane, with the first and second balancing plane being spaced from each other along an axis of the rotor, wherein each projection is provided for supporting, where necessary, a balancing weight, wherein the device includes:

a first engaging member for engaging with either a portion of the rotor at or near the first set of projections, or for engaging with one of the projections of the first set of projections, which projection supports or holds at least one balancing weight;

a second engaging member for engaging with one of the projections of the second set of projections, which projection supports or holds at least one balancing weight;

a first movement mechanism for effecting relative movement between the first and second engaging members; and

a controller for controlling the first movement mechanism so as to cause the first or second engaging member to engage the projection supporting or holding the at least one balancing weight and impart a force to said projection, which force is sufficient enough to deform said projection so as to attach the balancing weight to the rotor and prevent or at least inhibit the balancing weight from being able to be removed from the projection.

2. A device according to claim 1 wherein the controller controls the first movement mechanism so as to cause the first engaging member to engage a projection of the first set of projections and the second engaging member to engage a projection of the second set of projections and impart a force to each projection, which force is sufficient enough to deform each projection so as to attach one or more balancing weights to each projection and prevent or at least inhibit the balancing weights from being able to be removed from the projections.

3. A device according to claim 1 or claim 2 wherein the first movement mechanism is configured for effecting movement of:

the first engaging member towards the second engaging member, and/or

the second engaging member towards the first engaging member. 4. A device according to any preceding claim wherein the first and/or second engaging members are slidably moveable.

5. A device according to any preceding claim wherein the device includes a support member for supporting the first and second engaging members.

6. A device according to any preceding claim wherein one of the first and second engaging member is connected to and fixed relative to the support member. 7. A device according to any preceding claim wherein the first engaging member is connected to and fixed relative to the support member and wherein the second engaging member is connected to but moveable relative to the support member so as to be moveable towards and away from the first engaging member.

8. A device according to any preceding claim wherein the first and second engaging members are spaced from the support member so as to provide a space for receiving at least a portion of the rotor.

9. A device according to any preceding claim wherein the first and/or second engaging members are configured for engaging with axially facing surfaces of the rotor / projections. 10. A device according to any preceding claim wherein the first and/or second engaging members move towards and away from each other in a direction which is substantially parallel with an axis of the rotor.

11. A device according to any preceding claim wherein the projection supporting or holding the at least one balancing weight is elongate and extends substantially parallel with an axis of the rotor and wherein the first or second engaging member is configured for engaging with said projection in a direction parallel with said axis. 12. A device according to any preceding claim wherein where the first or second engaging member is configured for engaging with and deforming a projection, a surface of the engaging member which engages the projection includes a recess, e.g. is concave, such that during the deformation pf the projection the cross-sectional area of the projection is increased.

13. A device according to any preceding claim wherein the first engaging member includes a recess for receiving all or a portion of one of the projections of the first set of projections. 14. A device according to claim 13 wherein the recess in the first engaging member is substantially cylindrical or conical.

15. A device according to claim 13 or claim 14 wherein the first engaging member includes an end face extending around an opening to the recess, with the end face being configured for engaging with a surface of the rotor, so as to ensure that little or no force is applied to the projection positioned within said recess.

16. A device according to any preceding claim wherein the first engaging member is positioned such that, in use, the first engaging member is configured to sit between adjacent projections of the first set of projections and engaging a portion of the rotor therebetween.

17. A device according to any preceding claim wherein the first and/or second engaging members are each moveable into engagement with the rotor

/ projections and wherein a feedback device is provided for each engaging member for determining when the engaging member has engaged its respective the rotor / projection. 18. A device according to claim 17 wherein the feedback device is based on force feedback, e.g. a load cell, or by monitoring the distance moved by the first and/or second engaging member relative to a datum.

19. A device according to any preceding claim wherein the device includes a plurality of said first engaging members.

20. A device according to any preceding claim wherein the device includes a plurality of said second engaging members. 21. A device according to any preceding claim wherein the device is configured for supporting / holding a further rotor, said further rotor being one which is not currently being balanced.

22. A device according to claim 21 wherein the device includes a further rotor supporting mechanism having a first part for engaging with a first portion of the further rotor and a second portion for engaging with a second portion of the further rotor.

23. A device according to claim 22 wherein the further rotor supporting mechanism includes a respective movement mechanism (“second movement mechanism”) for effecting relative movement between the first and second parts.

24. A device according to claim 23 wherein the second movement mechanism effects sliding movement of the second part towards and away from the first part.

25. A device according to any one of claims 22 to 24 wherein the first and second parts are spaced from the support member so as to provide a space for receiving at least a portion of the further rotor.

26. A device according to any one of claims 22 to 25 wherein the first and second engaging parts are configured for engaging with axially facing surfaces of the further rotor.

27. A device according to any one of claims 22 to 25 wherein, in use, the second engaging part moves towards and away from the first engaging part in a direction which is substantially parallel with an axis of the further rotor. 28. A device according to any one of claims 22 to 27 wherein a surface of the support member to which the first and second engaging members are connected is inclined at an angle to a surface of the support member to which the first and second parts are connected. 29. A device according to claim 28 wherein the support member is triangular or substantially triangular in cross-section, e.g. when looking at a plane which extends substantially perpendicularly to the axis of the rotor being balanced and/or the further rotor.

30. A device according to any preceding claim wherein the first and/or second movement mechanism is or includes a linear actuator, e.g. a ball- screw actuator or a hydraulic actuator.

31. A device according to any preceding claim wherein the device is or includes a robotic mechanism for moving the first and second engaging members into position relative to the rotor to be balanced.

32. A device according to any preceding claim where dependent on claim 5 wherein the robotic mechanism is connected to the support member. 32. A device according to any preceding claim where dependent on claim 5 the support member is connected to a linkage mechanism enabling the support member to be moved into and out of position relative to a rotor being balanced. 33. A device according to any preceding claim wherein the device is configured for use with annular balancing weights which are placed on to and supported by projections which are elongate and substantially cylindrical / conical. 34. A balancing apparatus including or in combination with a device according to any one of claims 1 to 33.

35. A balancing system including balancing apparatus and a device according to any one of claims 1 to 33.

36. The balancing apparatus or system of claim 34 or 35 including a plurality of supports for supporting the rotor to be balanced such that it may be rotated about its axis. 37. The balancing apparatus or system of claims 34 to 36 including the balancing machine includes a device or mechanism for driving rotation of the rotor.

38. The balancing apparatus or system of claim 37 wherein drive is applied to a peripheral surface of the rotor to cause it to rotate.

39. The balancing apparatus or system of claims 34 to 38 including a device for measuring unbalance of the rotor and for determining where, and what weight, balancing weights are required to be attached to the projections of first and second sets of projections of the rotor.

40. The balancing apparatus or system of claims 34 to 39 including a device for placing one or more balancing weights on one or more projections of the first or second set of projections of the rotor, whilst the rotor is in position in the balancing apparatus.

41. The balancing apparatus or system of claim 40 wherein the balancing weight placing device is capable of collecting a desired balancing weight or weights from a location, moving the weight or weights to the rotor to be balanced and placing the weight or weights on one or more projections of the first or second set of projections of the rotor.

42. The balancing apparatus or system of claim 41 wherein the balancing weight placing device is or includes a robotic mechanism.

43. The balancing apparatus or system of claim 41 or claim 42 wherein the balancing weight placing device picks up one or more balancing weights by, for examples, utilisation of a suction device, an electromagnetic or a gripping mechanism.

44. A device, balancing apparatus or system according to any preceding claim wherein the rotor is an electric rotor.

45. A device, balancing apparatus or system according to any preceding claim wherein the first set of projections is connected to and extends axially away from a first axially facing end surface of the rotor, and wherein the second set of projections is connected to and extends axially away from a second axially facing end surface of the rotor. 46. A device, balancing apparatus or system according to any preceding claim wherein the first set of projections extends away from the first axially facing end surface of the rotor in a direction substantially perpendicular thereto, and wherein the second set of projections extends away from the second axially facing end surface of the rotor in a direction substantially perpendicular thereto.

47. A device, balancing apparatus or system according to any preceding claim wherein elongate axes of the first set of projections are parallel with each other.

48. A device, balancing apparatus or system according to any preceding claim wherein elongate axes of the second set of projections are parallel with each other.

49. A device, balancing apparatus or system according to any preceding claim wherein elongate axes of the first and second set of projections are parallel with each other. 50. A device, balancing apparatus or system according to any preceding claim wherein the rotor includes a plurality of cooling fins or blades, with the projections being positioned between respective blades, e.g. one or more projections positioned between adjacent cooling fins or blades. 51. A device, balancing apparatus or system according to any preceding claim wherein the system provides rotor position location information to the device for attaching one or more balancing weights to a rotor, such that the first and second engaging members of the device may automatically be aligned with the rotor and the projections thereof before the respective projection(s) is deformed by the engaging member(s).

52. Any novel feature or novel combination of features described herein and/or in the accompanying drawings.

Description:
Title: Device for Attaching Balancing Weights to a Rotor

Description of Invention

This invention relates to a device for attaching one or more balancing weights to a rotor, such as, for examples an electric rotor, to be balanced, and also to a balancing apparatus including or used in combination with such a device.

Such may be formed of a single rotor portion or multiple rotor portions linked together in end-to-end alignment. Rotors formed of multiple rotor portions may comprise two or three such portions, and less commonly may comprise four portions. The rotor portions are often connected to each other in an articulated fashion, and often adjacent rotor portions can“plunge” relative to each (e.g. they can move axially relative to each other) and the articulate joints can sometimes plunge.

Balancing is typically carried out on rotors to overcome or lessen the problem of ‘unbalance’ - the uneven distribution of mass around the axis of rotation of the rotor. Unbalance is when the inertia axis of the rotor is offset from its central axis of rotation, which results from the mass of the rotor not being distributed uniformly about its central axis. Rotors suffering unbalance may generate a moment when rotating which leads to vibration.

It is known to balance a single piece rotor using two balance planes. Each balance plane is a plane disposed substantially perpendicular to the axis of the rotor. When balancing a multiple piece rotor, balancing is carried out in additional balance planes: a two piece rotor may be balanced in three planes, a three piece rotor may be balanced in four planes, and a four piece rotor may be balanced in five planes. Correction for unbalance is typically carried out by adding one or more balance weights to the rotor. Rotors are typically designed with zones where balance weights can be added corresponding to the number of balancing planes, which are often near the end of a rotor portion.

The mechanism for correcting unbalance is typically automated, by which balance weights are attached to the rotor at a set position along the axis of the rotor for each plane, within specified balance zones, and at a desired angular position (e.g. circumferential position) around an axis of the rotor. Once weights for all planes (where required) are applied to the rotor, the rotor unbalance is, typically, measured again using the same method. If the unbalance measured in any plane remains outside of a predefined tolerance threshold, a second step of correction may be carried out within the corresponding balance zone. There are many known methods for attaching balancing weights to a rotor to be balanced, and these depend on the characteristics of the balancing weight. For example, it is known to attach a balancing weight by welding, e.g. induction welding, or by adhering.

To perform the balancing process a rotor is loaded into a balancing machine that includes a device or mechanism for driving rotation of the rotor (said loading is typically manual, but can be automated, e.g. using a robot or the like). Each end of the rotor is located in a respective mounting apparatus that may include a chuck to secure that end of the rotor. One or both of the mounting apparatuses may be driven by a drive mechanism so as to transfer torque to the rotor. Alternative driving mechanisms might be utilised, for example where drive is applied to a peripheral surface of the rotor to cause it to rotate, e.g. a belt drive where the belt engages a portion of the rotor.

According to a first aspect of the invention we provide a device for attaching one or more balancing weights to a rotor, the rotor including first and second sets of projections, the first set of projections being positioned in a first balancing plane and the second set of projections being positioned in a second balancing plane, with the first and second balancing plane being spaced from each other along an axis of the rotor, wherein each projection is provided for supporting, where necessary, a balancing weight, wherein the device includes:

a first engaging member for engaging with either a portion of the rotor at or near the first set of projections, or for engaging with one of the projections of the first set of projections, which projection supports or holds at least one balancing weight;

a second engaging member for engaging with one of the projections of the second set of projections, which projection supports or holds at least one balancing weight;

a first movement mechanism for effecting relative movement between the first and second engaging members; and

a controller for controlling the first movement mechanism so as to cause the first or second engaging member to engage the projection supporting or holding the at least one balancing weight and impart a force to said projection, which force is sufficient enough to deform said projection so as to attach the balancing weight to the rotor and prevent or at least inhibit the balancing weight from being able to be removed from the projection.

According to a second aspect of the invention we provide a balancing apparatus including a device according to the first aspect of the invention.

According to a third aspect of the invention we provide a balancing system including balancing apparatus and a device according to the first aspect of the invention. Further features of the various aspects of the invention as set out in the dependent claims appended hereto.

Embodiments of the various aspects of the invention will be described by way of example only with reference to the accompanying drawings, of which:

Figure 1 is a perspective view of a system for balancing a rotor;

Figure 2 is a perspective view of parts of the system of figure 1 showing a rotor to be balanced being collected from a rotor support apparatus;

Figure 3 is a close up perspective view of a portion of figure 2;

Figure 4 is a side view of parts of the system of figure 1 showing a rotor being positioned in a balancing apparatus of the system;

Figure 5 is a close up perspective view of a portion of figure 4;

Figure 6 is a perspective view of a rotor positioned in a balancing apparatus of the system of figure 1 ;

Figure 7 is a perspective view of the system of figure 1 showing a balancing weight being added to the rotor; Figure 8 is a close up perspective view of a portion of figure 7;

Figure 9 is a perspective view of the system of figure 1 showing a device thereof attaching a balancing weight to the rotor; Figure 10 is a close up perspective view of a portion of figure 9; Figure 11 is a close up perspective view of the device of figure 9;

Figure 12 is a further perspective view of the device for attaching a balancing weight to the rotor;

Figure 13 is a front view of the rotor, balancing apparatus and device for attaching a balancing weight corresponding to the relative positions of the parts in figure 9; Figure 14 is a rear view of the rotor, balancing apparatus and device for attaching a balancing weight corresponding to the relative positions of the parts in figure 9;

Figure 15 is an end view of the rotor, balancing apparatus and device for attaching a balancing weight corresponding to the relative positions of the parts in figure 9;

Figure 16 is a close up view of an end of the rotor showing a balancing weight in position on a projection of the rotor;

Figure 17 is a close up view of an end of the rotor showing a balancing weight which has been attached and held in position relative to the rotor by deformation of the projection; Figure 18 is a side, cross-sectional, view of the balancing weight positioned on the projection of the rotor;

Figure 19 is a perspective view showing the deformed projection holding the balancing weight in position on the rotor; and Figure 20 is a side, cross-sectional, view of the balancing weight attached to the rotor and held in position relative to the rotor by the deformed projection of the rotor. Referring to the figures these show a system 10 for use in balancing a rotor 11. Whilst the embodiments disclosed below relate, in particular, to an electric rotor with particular design considerations, it should be appreciated that the inventive concept disclosed herein could equally apply to other forms of rotor. As can be seen from the figures, the rotor 11 which is to be balanced using the system 10 is rotatable about a rotor axis A and is elongate with end most cylindrical rotor portions 11 a, 11 b which are connected to each other by a larger diameter generally central cylindrical section 11 c. Axially facing end surfaces of the central section 11 c are provided with an array of circumferentially spaced cooling fins/blades 11 e (see Figures 16 and 17). The rotor 11 is provided with a circular array of first and second sets of projections 11 p, each set of projections being provided at respective axially facing end surfaces of the central section 11 c. Thus, a first set of projections 11 p is provided on the axially facing end surface of the central section 11 c positioned adjacent the rotor portion 11 b, and a second set of projections 11 p is provided on the opposite axially facing end surface of the central section 11 c, which surface faces the rotor portion 11 a. In the examples disclosed herein, each projection 11 p is generally cylindrical or nominally conical (e.g. a truncated cone) and is elongate with an elongate axis thereof being parallel to the rotor axis A. Thus, in the rotor 11 in the present example the elongate axes of all of the projections 11 p are aligned substantially parallel with each other and with the rotor axis A. The projections 11 p are spaced from each other generally around the circumference (near the circumference) of the rotor section 11 c and are positioned such that two projections 11 p are positioned between adjacent cooling fins/blades 11 e. Each of the projections 11 p is configured to receive and support a generally annular shaped balancing weight 70 as shown in Figures 18, 19 and 20. The balancing weights 70 are placed onto/over the projections 11 p as described in more detail below and are held in that position by deformation of the protection 11 p, again discussed in more detail below.

It should be appreciated that whilst in the present example the projections 11 p are provided on axially facing end surfaces of the central section 11 c of the rotor 11 , they could be positioned elsewhere on the rotor. In addition, the projections 11 p need not necessary be elongate/cylindrical/conical, but could take any suitable form appropriate to support a balancing weight (which may or may not be annular) provided that the projection is deformable so as to permanently attach the balancing weight to the rotor 11. As can be seen from the figures the system 10 includes a user control module 15. The system 10 also includes a balancing apparatus 20 which supports the rotor 11 for rotation about the rotor axis A so that it can be balanced. To achieve this, the balancing apparatus 20 includes two first supports 24 one positioned to each side of the central section 11 c of the rotor 11. Each support 24 provides at an upper end thereof, adjacent the rotor 11 , a pair of rollers 25 which engage with and support the respective end rotor portions 11 a and 11 b for rotation. The rollers are rotatable about respective axes which are parallel to axis A. The supports 24 are slidably moveable and supported by a base 20a such that their relatively positions can be adjusted, e.g. for different lengths/sizes of rotor.

Two second supports 21 are provided, one positioned outwardly of each support 24. The supports 21 are also slidably supported by the base 20a and moveable relative thereto. These supports 21 are provided so as to axially align the rotor 11 in the balancing apparatus 20. This is achieved by providing at their upper end, substantially in line with the axis A, a moveable rod 22 which has supported at its free end a rotatable member 23. The rollers 23 are free to rotate about respective axes which are substantially perpendicular to the axis A (they need not be exactly perpendicular). The rods 22 can be moved laterally towards and away from the support 21 so as that the roller is positioned where the end of the rotor portion 11 a, 11 b is required to be positioned in order for the balancing process to be performed. Again, the supports 21 can be moved on the base 20a towards and away from each other so as to be positioned for different lengths/sizes of rotor. In order for balancing to take place, the rotor 11 needs to be rotated about its axis A so that the balancing apparatus 20 can sense/measure unbalance of the rotor 11 and determine where balancing weights 70 are required to be positioned (e.g. attached to the projections 11 p of the first and second sets of projections of the rotor 11 ). In this particular embodiment a device 50 is provided for driving the rotor 11 which includes a number of pulleys 52 (with axes of rotation substantially parallel with the rotor axis A) which support a belt 51. One of the pulleys 52 is driven by a suitable motor. The device 50 is moveable towards and away from the supported rotor 11 in a direction substantially transverse to the axis A, such that a lower portion of the belt 51 engages with an upwardly facing exterior surface 11 d of the central section 11 c of the rotor 11. The rotor 11 is caused to rotate as a result of the friction between the belt 501 and that surface 11 d.

Once unbalance of the rotor 11 has been measured and the balancing apparatus 20 has determined where and what weight balancing weights 70 are required to be attached to the projections 11 p, it is necessary to apply those balancing weights 70 to the projections. Whilst this can be achieved manually by a system operator, the present system 10 has automated this process by providing, in this example, a number of balancing weight storage devices 32, 33, 34, each of which stores and provide access to balancing weights of differing masses. In order to improve the efficiency of the balancing process, the system 10 includes a device 30 for picking and placing the balancing weights on the respective projections 11 p of the rotor 11 whilst the rotor 11 is in position in the balancing apparatus 20. This is achieved by a robotic mechanism which picks the required weight(s) from the storage devices 32, 33, 34 and places it on the desired projection 11 p. In this particular example the device for picking and placing the balancing weight(s) may utilise a suction device, an electromagnetic or a gripping mechanism 31 for grasping/holding the balancing weight during its transition from the storage devices 32, 33, 34 to the respective projection 11 p. It should be appreciated, of course, that any suitable picking and placing device could be utilised.

In order for the picking and placing device 30 to know where to place the weights, the system 10 preferably provides rotor position location information to the device 30, in particular providing the locations of some or all of the projections 11 p so that the picking and placing device 30 is able to place the one or more respective balance weights on one or more of the projections 11 p of the rotor 11.

Once the balancing weights 70 have been added to the projections 11 p of the rotor, it may be desired, although not necessary, to measure again for any potential unbalance in the rotor 11 by rotating about its rotor axis A, before the balancing weights are permanently attached to the rotor. Whether or not that secondary balancing assessment is carried out, it is necessary subsequently to placement of the weights 70 to permanently attach them to the rotor 11 , otherwise they would fall off of the projections 11 p. In order to achieve this attachment, the system 10 includes a device 40 for attaching the balancing weights 70 to the rotor. It will be noted from the figures that the device 40 incorporates a robotic mechanism enabling it to move towards and away from the balancing apparatus 20, but it should be appreciated that a robotic mechanism is not essential. Likewise, whilst the device 40 for attaching the balancing weights 70 to the rotor is shown in this embodiment to carry out the attaching process whilst the rotor 11 is supported in the balancing apparatus 20, that need not be the case. Indeed, embodiments are envisaged where the rotor 11 , after balancing has been measured and the balancing weights have been placed over the projections 11 p, is moved to another location for the attachment process to take place.

The device 40 for attaching the balancing weight(s) 70 to the rotor 11 acts so as to engage with the projection 11 p (or more than one projection) supporting one or more balancing weights 70 and to impart a force to that projection(s) 11 p which is sufficiently enough to deform that projection(s) 11 p so that it is difficult (and preferably impossible, without further mechanical intervention) to remove the balancing weight(s) 70 from the respective projection 11 p.

In the present embodiment the device 40 has a first engaging member 46b with a portion 62 for engaging with a portion of the axially facing end surface of the central section 11 c of the rotor 11 adjacent the rotor portion 11 b. In envisaged embodiments the portion 62 may be provided for engaging with one of the projections 11 p on that side of the rotor 11. The device 40 also includes a second engaging member 46a with a portion 61 the purpose of which is to engage with one of the projections 11 p on the second set of projections positioned on the axially facing end surface of the central section 11 c of the rotor 11 adjacent the rotor portion 11a. In this particular example the device 40 includes a support member 41 positioned at a free of the robotic mechanism for supporting the first and second engaging members 46a, 46b. In this particular embodiment the first engaging member 46b is connected to and fixed relative to the support member 41 and the second engaging member 46a is connected to but slidably moveable relative to the support member 41 along a sliding rail 47. This means that relative movement can be achieved between the first and second engaging members 46a, 46b by slidable movement of the second engaging member 46a towards and away from the first engaging member 46b.

In this particular example a first movement mechanism 48 is provided for effecting the sliding movement of the second engaging member 46a towards and away from the first engaging member 46b. The mechanism 48 includes a balls-crew linear actuator driven by a motor 49 so as to slide the second engaging member 46a in the direction shown by the arrows 49a on its sliding rail 47. It should be appreciated that many other forms of movement mechanism could be provided in order to affect movement of the second engaging member 46a towards and away from the first engaging member 46b, for example a hydraulic actuator or another form of electrically driven actuator.

Whilst not utilised in the present embodiment it should be noted that embodiments are envisaged where the first engaging member 46b is moveable towards and away from the second engaging member 46a, with the latter being connected to and fixed relative to the support member 41. In yet a further alternative embodiment, both the first and second engaging member 46a, 46b may be connected to and moveable, e.g. slidably, relative to the support 41 , such that they can each move towards and away from the respective other engaging member.

In more detail the first engaging member 46b includes a generally cylindrical projection 62 which is spaced from the support member 41 and extends towards the second engaging member 46a generally in the direction of sliding movement of the second engaging member 46a. Likewise the second engaging member 46a also includes a generally cylindrical projection 61 which extends towards a first engaging member 46b in the direction substantially parallel with the sliding movement of the second engagement member 46a. It will be seen from the figures, in particular Figure 13, that the portions 61 , 62 are spaced from the support member 41 so as to provide a space for receiving the central section of the rotor 11 c.

In the present embodiment the projections 61 , 62 of the first and second engaging members 46a, 46b are configured for engaging with and deforming respective projections 11 p on the central section 11 c of the rotor. This is achieved by the projections 61 , 62 being aligned with the respective projections 11 p and then the first movement mechanism 48 being actuated to move the projection 61 towards the projection 62. The movement provides a force which is sufficient enough to deform at least the projection 11 p with which portion 61 engages.

In other embodiments, it may be desirable only for the portion 61 to cause deformation of any one of the projections 11 p (at either side of the rotor 11 ) with the projection 61 simply engaging with the axially facing end surface of the central section 11 c of the rotor 11 to provide a reactionary force during the deformation process. Thus, it would be necessary for the support member 42 to be rotatable by the robotic mechanism in order to move the position of the second engaging member 62 to the other side of the central section 11 c of the rotor 11 , if balancing weights are required at that side of the rotor 11. This functionality is provide by the robotic mechanism through rotational connection 40a, to rotate the support member 41 in the direction of the arrow 40b.

In envisaged embodiments, however, where both the first and second engaging members 46a, 46b are slidably moveable relative to the support, it would not be necessary to rotate the support member 41 , because deformation can be achieved on both sides of the central section 11 c of the rotor 11 by both projections 61 , 62. It should be appreciated that where the engaging projections 61 , 62 are configured for engaging with and deforming a projection 11 p, the surface of the deforming projection 61 , 62 may include a recess 62a, e.g. as concave (see figure 17), such that during the deformation of the projection 11 p the cross sectional area of the projection 11 p is increased (see figure 20). In yet a further alternative embodiment, the engaging projection 62 of the first engaging member 46b may include a recess for receiving all or a substantial portion of one of the projections 11 p. Thus, the projection 62 may be configured to envelop or surround the projection 11 p which is positioned opposite the projection 11 p which is desired to be deformed. In such an embodiment, the recess provided in the engaging projection 62 may be substantially cylindrical or conical and larger than the projection 11 p which it needs to receive and may include an end face extending around an opening to the recess which engages with the axially facing surface of the rotor section 11 c. This ensures that little or no force is applied to that particular projection 11 p during the deformation process of the projection 11 p positioned on the opposite end of the rotor 11.

It will be noted that during the deformation process it is important to determine when a sufficient deformation of the projection 11 p has been achieved. Thus, the device 40 is provided with a one or more feedback devices, e.g. one for each of the first and second engaging members 46a, 46b for determining when the respective portions 61 , 62 has engaged and deformed its respective projection 11 p. The feedback devices may take the form of force feedback, e.g. including a load cell, or by monitoring the distance moved by the first and/or second engaging members 46a, 46b and/or the projections 61 , 62, relative to a datum.

Whilst in the present example the device 40 includes one first engaging member 46b and one second engaging member 46a, it should be appreciated that embodiments are envisaged including a plurality of said first engaging members and/or a plurality of said second engaging members. In other words the device could be configured for deforming multiple projections 11 p at one or both sides of the central section 11 c of the rotor 11 at the same or substantially the same time, or at least during one attachment process whilst the rotor is supported in the balancing apparatus 20.

Advantageously, the device 40 is also configured for supporting/holding a further rotor, said further rotor being one which is not currently being balanced. This is achieved by providing a support mechanism 43 connected to the support member 41 which includes a further rotor supporting mechanism having a first part 43a for engaging with a first portion or side of the further rotor and a second portion 43b for engaging with a second portion or side of the further rotor. In a similar fashion to the movement mechanism 48, 49, the further rotor supporting mechanism includes a respective movement mechanism, hereinafter referred to as the“second movement mechanism”, for effecting relative movement between the first and second parts 43a, 43b such that they are moveable towards and away from each other, preferably by sliding movement in the direction as indicated by the arrows 44. Again, the first and second parts 43a, 43 are spaced from the support member 41 so as to provide a space for receiving the rotor 11 , in this case the central portion 11 c of the further rotor 11 and in particular include formations for engaging with axially facing end surfaces of the central section 11 c of the rotor.

The provision of the further rotor supporting mechanism 43 is advantageous because once balancing has been achieved on the rotor 11 supported in the balancing apparatus 20, that rotor can be removed (either manually or automatically, e.g. by a further robotic mechanism), before the support member 41 is then rotated in order to move the further rotor into the balancing apparatus 20. In addition, the further rotor supporting mechanism 43 can be used to collect the next rotor to be balanced from rotor storage devices 12, and transport a fully balanced rotor back to the storage device 12. In order to reduce the time taken for loading of the further rotor into the balancing apparatus 20, a surface of the support member to which the first and second engaging members 46a, 46b are connected is inclined at an angle to a surface of the support member 41 to which the first and second parts 43a, 43b are slidably connected. As can be seen from the figures, the support member 41 is triangular or substantially triangular in cross-section. Whilst in the present example a robotic mechanism is connected to the support member 41 for moving the support member 41 , it should be appreciated that the support member 41 could be connected to a linkage mechanism enabling the support member 41 to be moved into and out of position relative to the balancing apparatus 20 and a rotor 11 being balanced. For example by utilising a counter balance or by utilising a self-compensating sliding mechanism. It is important for any such linkage mechanism to be configured accurately to position the first and second engaging members 46a, 46b relative to the rotor so as to ensure that adequate deformation of the projections 11 p is achieved without effecting any movement of the rotor 11 along the axis A.

When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.