WO2014181102A1

WO2014181102A1 - Device for driving a rotatable member

Info

Publication number: WO2014181102A1
Application number: PCT/GB2014/051392
Authority: WO
Inventors: Steve FOWLER
Original assignee: Universal Balancing Limited
Priority date: 2013-05-10
Filing date: 2014-05-07
Publication date: 2014-11-13
Also published as: GB2513906A; GB201308427D0; GB2513906B

Abstract

A device for engagement with a first connection part provided on or at an end of a rotor, the device including: a connection member for connecting the device to a rotation input member; and an engagement member which extends transversely either side of an axis of rotation of the device and having a pair of substantially diametrically opposing end portions, said opposing end portions of the engagement member being resiliently deformable towards and/or away from each other.

Description

Title: Device for driving a rotatable member Description of Invention

The present invention relates to a device for driving a rototable member. In particular, but not exclusively, this invention relates to a device for rotating an input shaft of a differential drive assembly, e.g. for a motor vehicle. More particularly, the device has been devised for use as part of an apparatus for balancing an input shaft of a differential drive assembly.

Balancing of an input shaft of a differential drive assembly is typically carried out to overcome or lessen the problem of 'unbalance' - the uneven distribution of mass around the axis of rotation of the input shaft. Unbalance is when the inertia axis of the input shaft is offset from its central axis of rotation, which results from the mass of the rotor not being distributed uniformly about its central axis. Input shafts suffering unbalance may generate a moment when rotating which leads to vibration, which can give rise to poor performance and potentially damage to the differential drive assembly.

An end of the input shaft remote from housing of a differential drive assembly is typically provided with a first connection part to facilitate its connection to a second connection part provided at an end of a rotor, e.g. a drive shaft. The first and second parts, when connected together with a third part, provide a flexible connection, with one such connection being known as a universal joint. In common practice, the first connection part provided on or at the end of the input shaft is what is known as an open universal joint part. In other words, it provide a recess to receive the third part, with there being some form of locking or clamping mechanism to hold the third part in the recess when the parts are assembled. Typically the recess is a part cylindrical recess which extends generally transversely of the axis of rotation of the input shaft, and typically the third part is a cylindrical part which is mounted for rotation about its elongate axis on or at the second connection part.

When balancing such input shafts it is necessary to hold in situ the housing of the differential drive assembly, e.g. by clamping the housing to a support platform, and then to rotate the input shaft whilst the unbalance, if any, in the input shaft is measured. In order to impart rotation to the input shaft, prior art balancing apparatus utilise a motor with an associated output drive rotor, which is connected to the first connection part at the end of the input shaft.

In one prior art apparatus, the free end of the drive rotor is provided with corresponding second and third parts (identical or equivalent to those which are provided on the rotor to which the drive assembly is intended to be connected when assembled). The parts are then connected to each other to form a universal joint. Balancing is then performed by driving the input shaft through the universal joint, but prior art apparatus utilising this configuration of parts suffers from inaccuracies as a result of the inherent "play" within the component parts of the universal joint. This "play" results in inaccurate balance measurements, which is undesirable.

In another prior art apparatus the free end of the drive rotor is provided with a mechanical engagement device which, when axially loaded (against the input shaft), has parts which engage the rotor. Balancing is then performed by driving the input shaft through the mechanical engagement device, but prior art apparatus utilising this configuration suffer from inaccuracies, due to the axial load required to achieve a positive engagement between the drive rotor and the input shaft.

The present invention has therefore been devised to address one or more of these problems. According to a first aspect of the invention we provide a device for engagement with a first connection part provided on or at an end of a rotor, the device including:

a connection member for connecting the device to a rotation input member; and

an engagement member which extends transversely either side of an axis of rotation of the device and having a pair of substantially diametrically opposing end portions, said opposing end portions of the engagement member being resiliently deformable towards and/or away from each other.

According to a second aspect of the invention we provide an apparatus for balancing a rotor, including a device according to the first aspect of the invention. According to a third aspect of the invention we provide an apparatus for balancing an input shaft of a differential drive assembly, including a device according to the first aspect of the invention.

Further features of the aspects of the invention are described in the appended claims.

Embodiments of the invention will now be described, by way of example only, with reference to the following figures, of which: Figure 1 is a perspective view of a device according to the present invention;

Figure 2 is a further perspective view of the device of figure 1 ;

Figure 3 is an underside view of the device of figure 1 ;

Figure 4 is a side view of the device of figure 1 ; Figure 5 is a side view of an engagement member of the device of figure 1 ; Figure 6 is an end view of the engagement member of figure 7;

Figure 7 is a close up view of an end portion of the engagement member of figures 5 and 6;

Figures 8a to 8d are perspective views of the device of figure 1 positioned close to but not yet engaged with a first connection part at an end of a rotor;

Figures 9a to 9d are perspective views of the device of figure 1 when engaged with the first connection part at an the end of a rotor; Figure 10 is a perspective view of a balancing machine including the device of figure 1 ; and

Figure 1 1 is a side cross-sectional view of the device of figure 1 engaged with an output shaft of a differential drive assembly.

Referring to the figures, these show a device 10 in accordance with the present invention for engagement with a first connection part 40 provided on or at the end of a rotor. The present invention relates to a device for driving the input shaft of a differential drive assembly, for example for a motor vehicle. However, it should be appreciated that the invention could be used for many other purposes. In particular, the device 10 has been devised for use as part of an apparatus 100 (see figure 10) for balancing the input shaft 60 of the differential drive assembly 200 in order to correct for unbalance therein. Such balance machines are well known in the art so will not be described in further detail herein, except as to say that the balancing machine includes a platform 300 or other support member for supporting the differential drive assembly 200, a motor 150 and a spindle arrangement 50 connected to the motor which is drivingly connectable to the device 10. The device 10 includes a connection member 12, which is substantially circular in plan view and provides for connecting the device 10 to the drive input shaft 50. The device 10 also includes an engagement member 14, which in this example is substantially semi-cylindrical and extends transversely either side of an axis rotation of the device 10. The engagement member 14, which can be seen in closer detail in figures 5 through 7, has a pair of substantially diametrically opposed end portions 16a, 16b each of which is semi-cylindrical. The end portions 16a, 16b of the engagement member 14 are advantageously configured to be resiliently deformable towards and away from each other. The advantage of such configuration will be apparent later.

The engagement member 14 is connected to and supported by a support part 40 which is substantially circular at its periphery and axially aligned with the connection member 12 to which it is connected by a pair of cylindrical parts 35. The part 30 has a generally annular peripheral portion 30a and a diametrically extending portion 30b to which the engagement member 14 is connected.

The connection of the engagement member 14 to the part 30b and the connection of the part 30 to the connection member 12 ensures that the engagement member 14 is free to move resiliently axially towards and away from the connection member 12 in use. It will be seen from figure 3 that a space 36 is provided in order to permit such resilient movement towards the connection member 12.

Referring specifically to figure 5 through 7, these show close-up views of the engagement member 14. It can be seen that the engagement member 14 includes a generally central portion 18 with a recess 18a to receive the part 30b. Connected to opposing ends of the central portion 18 is a pair of end portions 16a, 16b. As shown in figure 7 each end portion 16a, 16b is connected to the central portion 18 by an extension portion 19a, 19b. A slot or recess 20a, 20b is provided between each end portion 16a, 16b and the central portion 18 in order to provide a volume 22 into which the end portion can resiliently move towards the central portion 18. The recess extends generally parallel to the axis of rotation of the device 10 and opens in a direction towards the end of the input shaft 60. A base 24 of the recess, which is substantially cylindrical in cross section, and which extends generally transversely to an elongate axis of the member 14, provides an area about which each end portion 16a, 16b can resiliently pivot relative to the central portion 18. The recess 20a, 20b is manufactured using a wire cutting method.

As can be seen from the figures the end portions 16a, 16b, the central portion 18 and the extension portions 19a, 19b are all formed from a single piece of material, e.g. a metallic material such as steel, and thus are formed as a single component part.

Figures 8a through 8d correspond to figures 9a through 9d, with the exception that in figures 8a through 8d the device 10 is shown just prior to its engagement with the first connection part 40. In figures 9a through 9d the device 10 is engagement with the first connection part 40.

In more detail, the first connection part 40 provides an open universal joint connection part which includes a part-cylindrical recess 41 at each side thereof to receive the engagement member 14. When the differential drive assembly is to be installed into, for example a motor vehicle, the first connection part 40 forms one part of a universal joint, with the other parts of the universal joint being provided at an end of a shaft, e.g. a drive shaft. The part cylindrical recesses 41 provide a pair of surfaces 42 each of which provides a respectively engagement surface for the end portions 16a, 16b. An end stop portion 43 is provided to the radially outwardly facing end of each recess 41 . These end stop portions 43, in end use on a motor vehicle, prevent too much in the way of lateral movement of the other parts of the universal joint, relative to the first connection part 40. However, they are advantageously used by the device 10 in accordance with the present invention to provide a tight fit with the engagement member 14 (see figure 1 1 ). Radially inwardly facing surfaces of the parts 43 includes a chamfer which provides for a relative automative alignment of the engagement member 14 in the part cylindrical recesses 41 .

Prior art systems which rely on driving the first connection part 40 of the differential drive assembly by way of a corresponding cylindrical part of a universal joint must be manufactured in order to fit in between the parts 43. This means that there must be a degree of "play" (i.e. lateral movement) in the system which is undesirable for balancing. Advantageously, the resilience of the end portions 16a, 16b towards each other provides for a tight engaging fit of the engagement member 14 in the recesses 41 and between the end stops 43. When the engagement member 14 is lowered into the recess 41 the end portions 16a, 16b engage the parts 43 and are moved towards each other until the engagement member 14 is fully engaged in the recesses 41 . The resilience of the material of the engagement member 14 ensures that a radially outwardly directed force is applied to the parts 43, which ensures that the device 10 and the first connection part 40 are held relative to each other.

In the event that the overall diametric distance of the free end faces of the end portions 16a, 16b is less than the distance between the parts 43, this will advantageously be removed once the device is rotated at the balancing speed. The reason for this is that the end portions 16a, 16b are also free to pivot away from each other outwardly about the base 24 of the recesses 22 and the effect of rotating the device 10 at the balancing speed gives rise to an effective centrifugal force which forces the end portions 16a, 16b to engage or further engage the parts 43. The resilient connection, i.e. floating connection, between the engagement member 14 and the connection part 12 ensures that axial displacement can occur between the spindle 50 and the first connection part 40 during balancing, due to the compliant movement therebetween.

Whilst in the present example the engagement member 14 is shown as being cylindrical or semi-cylindrical, it should be appreciated that other shapes of the engagement member could be contemplated which would provide the desired functionality of the present invention. It should also be understood, as it will be one skilled in the art, that the device in accordance with the present invention can be utilised in other forms of balancing, not only those where the input shaft of a differential drive assembly is to be balanced. 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.

Claims

1 . A device for engagement with a first connection part provided on or at an end of a rotor, the device including:

a connection member for connecting the device to a rotation input member; and

2. A device according to claim 1 wherein the end potions are connected to each other by a further portion, and wherein the connection of each end portion to the further portion is resiliently deformable.

3. A device according to claim 2 wherein each end portion is connected to the further portion by an extension portion.

4. A device according to claim 3 wherein the extension portion permits the end portion to move resiliently relate to the further portion.

5. A device according to claim 3 or claim 4 wherein there is provided a recess between each end portion and the further portion.

6. A device according to claim 5 wherein the recess extends generally parallel to the axis of rotation of the device and opens in a direction towards the end of the rotor.

7. A device according to claim 5 or claim 6 wherein the recess provides a volume into which the end portion can resiliently move.

8. A device according to claim 5, claim 6 or claim 7 wherein a base of the recess provides an area about which each end portion can resiliently pivot.

9. A device according any preceding claim wherein, when the device is rotated, the end portions are free to move resiliently away from each other.

10. A device according to any one of claims 3 to 9 wherein the end portions, the further portion and the extension portions are formed as a single component part.

1 1 . A device according to any one of claims 3 to 9 wherein the end portions, the further portion and the extension portions are formed from a single piece of material, e.g. a metallic material.

12. A device according any preceding claim wherein the engagement member is connected to a support part which is resiliently moveable relative to the connection member.

13. A device according to claim 12 wherein the support part and the connection member provide a resilient connection in and axial direction.

14. A device according any preceding claim wherein the engagement member is part cylindrical.

15. A device according any preceding claim wherein the surface of the engagement member which, in use, engages the end of the rotor is substantially semicylindrical.

16. A device according any preceding claim wherein the device includes one or more locating members for engagement with a first connection part connected to the end of the rotor so as to locate the device relative thereto.

17. A device according any preceding claim wherein the device includes a pair of said locating members, positioned substantially diametrically opposite each other about the axis of rotation of the device.

18. A device according claim 16 or claim 17 wherein the locating members extend axially towards the end of the rotor.

19. A device according claim 16, claim 17 or claim 18 wherein the locating members are configured to engage in recesses or apertures in the first connection part at the end of the rotor.

20. A device as hereinbefore described with reference to and/or as shown in the accompanying drawings.

21 . An apparatus for balancing a rotor as hereinbefore described with reference to and/or as shown in the accompanying drawings.

22. An apparatus for balancing an input shaft of a differential drive assembly as hereinbefore described with reference to and/or as shown in the accompanying drawings.

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