Jacking assembly for a jack-up vessel

Abstract

Jacking assembly for a jack-up vessel, comprising: a pinion unit comprising a pinion to be engaged with a leg-mounted rack and a transmission arranged to couple the pinion to a motor for driving the pinion about a pinion rotation axis defining an axial direction of the jacking assembly; a support structure supporting the pinion; and a transmission housing enclosing the transmission and configured to hold transmission fluid for the transmission and to allow the pinion and the motor to connect to the transmission from outside the transmission housing. The transmission housing comprises a first housing section proximal to the pinion formed by the support structure, and a second housing section more distal from the pinion outside the support structure. A flexible third housing section between the first and second housing sections is configured to provide transverse and axial play between the first housing section and the second housing section.

Description

[0001] P137518PC00

[0002] Title: Jacking assembly for a jack-up vessel

[0003] FIELD

[0004] The invention relates to a jacking assembly for a jack-up vessel, as well as to a jack-up vessel comprising the jacking assembly.

[0005] BACKGROUND

[0006] Jacking assemblies for a jack-up vessel are known as such. A known jacking assembly comprises a pinion unit comprising a pinion to be engaged with a leg-mounted rack and a transmission arranged to couple the pinion to a motor for driving the pinion about a pinion rotation axis. A support structure supports the pinion. A transmission housing partly formed by the support structure encloses the transmission and is configured to hold transmission fluid for the transmission while allowing the pinion and the motor to connect to the transmission from outside the transmission housing. There is a desire to reduce weight of such jacking assemblies, in particular while maintaining or improving their performance. It is also desired to make production and installation of such jacking assemblies easier.

[0007] SUMMARY

[0008] An object is to reduce weight of jacking assemblies, in particular while maintaining or improving their performance. An object is to make production and / or installation of jacking assemblies easier. An object is to at least provide an alternative jacking assembly.

[0009] An aspect provides a jacking assembly for a jack-up vessel. The jacking assembly comprises a pinion unit comprising a pinion to be engaged with a leg-mounted rack and a transmission arranged to couple the pinion to a motor for driving the pinion about a pinion rotation axis defining an axial direction of the jacking assembly. The jacking assembly comprises a support structure supporting the pinion. The jacking assembly comprises a transmission housing enclosing the transmission and configured to hold transmission fluid for the transmission and to allow the pinion and the motor to connect to the transmission from outside the transmission housing.

[0010] The transmission housing comprises a first housing section proximal to the pinion and a second housing section more distal from the pinion, wherein the first housing section is formed by the support structure, wherein the second housing section is outside the support structure.

[0011] Since the first housing section is formed by the support structure, the same material can provide a dual function, thus allowing weight reduction compared to when the transmission housing would be completely separate from the support structure. Meanwhile, the second housing section allows the motor to connect the transmission to extend beyond the support structure, so that the support structure need not be enlarged merely to accommodate a relatively large transmission.

[0012] The transmission housing comprises a flexible third housing section between the first housing section and the second housing section, wherein the third housing section is configured to provide transverse and axial play between the first housing section and the second housing section, in particular to thereby provide transverse and axial play between the transmission and the support structure.

[0013] In a known jacking assembly, such a second housing section is rigidly fixed to such a first housing section, wherein the transmission is transversely and axially fixed with respect to the second housing section. It has been found that, when the pinion receives a transverse load, this tends to cause adverse reaction forces, e.g. a bending moment, between the transmission and the transmission housing. As a result, the transmission and transmission housing have to be dimensioned to sufficiently resist such reaction forces, which tends to require additional material and thus weight. Advantageously, by providing the flexible third housing section, such adverse reaction forces can be substantially prevented, while still allowing the above described dual use of the support structure and the extension of the transmission beyond the support structure. In particular, the transverse and axial play provided by the third housing section can allow the first housing section and the transmission to deform with respect to each other under load. Meanwhile, the support structure itself can remain sufficiently stiff to provide its supporting function, and the transmission as a whole can remain transversely and axially fixed with respect to the second housing section, in particular without introducing additional play within the transmission itself.

[0014] As a further advantage, the flexible third housing section can make production and installation of the jacking assembly easier, as the flexibility of the third housing section can effectively compensate for possible small misalignments or other imperfections. Thus, machining tolerances may be relaxed and installation steps may be performed in a more convenient manner and order.

[0015] Optionally, the third housing section circumferentially surrounds the transmission. Optionally, the third housing section axially and / or radially spaces the second housing section apart from the first housing section. In this way, the transverse and axial play can be provided particularly effectively.

[0016] Optionally, the jacking assembly comprises a torque arm arrangement for resisting rotation between the second housing section and the first housing section about the pinion rotation axis. In this way, advantageously, torsional reaction forces from operation of the transmission can still be transmitted to the support structure, in particular without straining the flexible third housing section.

[0017] Optionally, the torque arm arrangement movably links the second housing section to the first housing section. Such linking can provide effective transmission of the torsional reaction forces, in particular without inhibiting the transverse and axial play. The torque arm arrangement may for example comprise a link hingingly connected to the second housing section and the first housing section, in particular at respective opposite ends of the link, preferably using respective ball joints arranged at different circumferential positions with respect to the pinion rotation axis. Such a torque arm arrangement may be external or internal with respect to the transmission housing, wherein an external torque arm arrangement may be shielded from exposure to transmission fluid by the transmission housing.

[0018] Optionally, the torque arm arrangement axially bridges the third housing section. In other words, the torque arm arrangement may interconnect the first and second housing sections at a distance from the third housing section. In this way, the transverse and axial play can be substantially unaffected by the torque arm arrangement.

[0019] As a possible alternative, the torque arm arrangement may fix one or more parts of the transmission and / or the second housing section with respect to the first housing section adjacent the third housing section at one or more circumferential positions with respect to the pinion rotation axis, wherein the one or more circumferential positions together define a circumferential range of less than 180 degrees, preferably less than 160 degrees, more preferably less than 140 degrees. Although such a torque arm arrangement imposes a limitation on the advantageous transverse and axial play, it has been found that such play can still be provided to some extent, thereby still providing an improvement compared to known jacking assemblies where the second housing section is rigidly fixed to the first housing section. Meanwhile, such a torque arm arrangement may be relatively robust. Such a torque arm arrangement may be external or internal with respect to the transmission housing, wherein an internal torque arm arrangement may be relatively compact. Optionally, the support structure supports the pinion at two axially spaced apart support positions along the pinion rotation axis, wherein the pinion is configured to engage the rack axially between the two support positions. Optionally, one of the support positions is at a proximal axial end of the first housing section. Optionally, the jacking assembly is configured to transversely and / or axially fix the transmission with respect to the second housing section. In this way, the jacking assembly can retain corresponding advantages of the known jacking assembly.

[0020] Optionally, the jacking assembly is configured to provide transverse and axial play between the transmission and the first housing section along an axial range bound by the support position that is at the proximal axial end of the first housing section. In this way, the advantages of the transverse and axial play as described elsewhere herein can be utilized particularly effectively. Thereto, the first housing section is preferably dimensioned to provide radial interspacing between the first housing section and the transmission.

[0021] Optionally, the transmission housing comprises a rigid fourth housing section between the first housing section and the third housing section, in particular wherein the fourth housing section is outside the support structure. In this way, the support structure may be reduced in axial size, in particular while maintaining essentially the same design for the second and third housing sections.

[0022] Optionally, the pinion unit comprises a further pinion to be engaged with the leg-mounted rack, wherein the transmission is further arranged to couple the further pinion to the motor for driving the further pinion about a further pinion rotation axis parallel to the pinion rotation axis, wherein the support structure further supports the further pinion, wherein the transmission housing is further configured to allow the further pinion to connect to the transmission from outside the transmission housing. In this way, advantageously, a same transmission can be used for driving two pinions, in particular two adjacent pinions, for example from a same motor. Additional weight reduction can be obtained thereby.

[0023] Optionally, the jacking assembly, in particular the pinion unit, further comprises the motor, wherein the motor is connected to the transmission for driving the pinion and preferably the optional further pinion. Alternatively, the motor may be provided separately from the jacking assembly to be connected thereto, e.g. upon installation. The motor is preferably arranged outside the support structure and is preferably connected to the transmission at the second housing section of the transmission housing.

[0024] Optionally, the transmission comprises a first transmission section proximal to the pinion and a second transmission section more distal from the pinion. Optionally, the jacking assembly is configured to inhibit exchange of transmission fluid between the first transmission section and the second transmission section within the transmission housing. Optionally, the first transmission section is mainly enclosed by the first housing section, wherein the second transmission section is mainly enclosed by the second housing section. Optionally, the first transmission section and the second transmission section are coupled to each other substantially without transverse and / or axial play therebetween. Optionally, the first transmission section is coupled to the second housing section, in particular via the second transmission section. Such an arrangement of a first transmission section and a second transmission section in a jacking assembly is known as such, and can advantageously be applied in the context of the present invention in combination with the flexible third housing section as described herein.

[0025] Optionally, the first transmission section is coupled to the second housing section independent from the second transmission section, in particular so as to transversely and / or axially fix the first transmission section with respect to the second housing section. Such an independent coupling may for example be provided using a bearing and may be additional or alternative to the optional coupling via the second transmission section as described above. Such an independent coupling may advantageously facilitate installation of the second housing section, the transmission and the pinion together as one unit with respect to the support structure. Meanwhile, the flexible third housing section can provide a desired tolerance during installation. By contrast, in a known jacking assembly, the first transmission section is typically installed before the second transmission section is installed.

[0026] A further aspect provides a jack-up vessel comprising at least one jacking assembly as described herein, wherein the respective support structure is supported on a hull of the jack-up vessel, wherein the respective pinion and optional further pinion are arranged to engage with a rack of a leg of the jack-up vessel. Such a jack-up vessel provides advantages corresponding to those described above with respect to the jacking assembly.

[0027] Optionally, the number of jacking assemblies of the at least one jacking assembly is at least two, preferably at least four, preferably wherein the jacking assemblies are arranged in pairs to engage with the rack from opposite lateral sides of the rack. In this way, multiple jacking assemblies can be used with a same rack, with benefits corresponding to those of a known jack-up vessel.

[0028] A further aspect provides a method of performing jacking operations in a jack-up vessel as described herein, wherein the pinion and optional further pinion are driven to move raise or lower the leg with respect to the hull, wherein, during the driving, at a distance from the pinion, the transmission moves transversely and / or axially with respect to the support structure using the transverse and axial play. Such a method provides advantages corresponding to those described above with respect to the jacking assembly and jack-up vessel. In particular, the transverse and / or axial movement can avoid undesired straining in the transmission. A further aspect provides a method of assembling a jacking assembly as described herein, wherein the third housing section is assembled to the first and / or second housing section, in particular while the support structure supports at least the pinion. In this way, the jacking assembly can be provided in a relatively effective and efficient manner, e.g. during onboard installation or in a prefabrication step on shore. The third housing section may for example be assembled to the first housing section before being assembled to the second housing section, or vice versa. Part or all of the transmission may be coupled to the pinion before the pinion is supported by the support structure. Thus, advantageously, the jacking assembly can be assembled in various ways, e.g. depending on circumstances.

[0029] It shall be appreciated that aspects and options described herein may be variously combined. So, for example, options described with respect to the jacking assembly may be correspondingly applied to the jacking vessel and methods, and vice versa.

[0030] DETAILED DESCRIPTION

[0031] In the following, the invention will be explained further using examples of embodiments and drawings. The drawings are schematic and merely show examples. In the drawings, corresponding elements are provided with corresponding reference signs. In the drawings:

[0032] Fig. 1 shows a sectional side view of a jack-up vessel;

[0033] Fig. 2 shows a perspective view of a part of a jack-up vessel including jacking assemblies and a leg-mounted rack;

[0034] Fig. 3 shows a perspective view of a part of a jack-up vessel including jacking assemblies, wherein the leg-mounted rack is not shown;

[0035] Figs. 4A and 4B show a sectional perspective view and a sectional top view, respectively, of a known jacking assembly; Figs. 5A and 5B show a sectional perspective view and a sectional top view, respectively, of a jacking assembly according to a first embodiment;

[0036] Fig. 5C shows a sectional perspective view of a detail of the jacking assembly of Figs. 5A-B;

[0037] Fig. 5D shows a further sectional perspective view of the jacking assembly of Figs. 5A-C;

[0038] Figs. 6A and 6B show a sectional top view and a sectional perspective view, respectively, of a jacking assembly according to a second embodiment; and

[0039] Figs. 7 A and 7B show a perspective view and a sectional perspective view, respectively, of a jacking assembly according to a third embodiment, wherein the support structure is shown partly opened.

[0040] Figs. 1-3 illustrate a jack-up vessel 1 comprising a hull 2 and legs 3 and jacking assemblies 4 for raising or lowering the legs 3 with respect to the hull 2 using a rack- and-p inion type jacking mechanism. The jacking assemblies 4 comprise a support structure 5 supported on the hull 2. Here, multiple jacking assemblies 4 share a common support structure 5-C, wherein respective sections of the common support structure 5-C may be considered as forming respective support structures 5 for the jacking assemblies 4. Pinions 6 of pinion units 7 of the jacking assemblies 4 are arranged to engage with a rack 8 of a leg 3 of the jack-up vessel 1.

[0041] In Fig. 3, the number of jacking assemblies 4 is four, wherein the jacking assemblies 4 are arranged in pairs to engage with the rack 8 from opposite lateral sides of the rack 8. Here, the pinion unit 7 of each jacking assembly 4 comprises a pinion 6 and a further pinion 6-F, as explained further elsewhere herein. Alternatively, each jacking assembly may comprise a respective single pinion. Figs. 5A to 7B show examples of jacking assemblies according to embodiments. Figs. 4A-B show a known jacking assembly, merely as a reference to aid in understanding of the invention.

[0042] In general, the jacking assembly 4 comprises a pinion unit 7 comprising a pinion 6 to be engaged with a leg-mounted rack 8 and a transmission 9 arranged to couple the pinion 6 to a motor 10 for driving the pinion 6 about a pinion rotation axis R defining an axial direction of the jacking assembly 4. The motor 10 may be considered part of the jacking assembly 4.

[0043] The jacking assembly 4 comprises a support structure 5, e.g. a section of the common support structure 5-C, supporting the pinion 6. The support structure 5 supports the pinion 6 at two axially spaced apart support positions Si, S2 along the pinion rotation axis R, in particular using respective pinion bearings 14. The pinion 6 is configured to engage the rack 8 axially between the two support positions Si, S2. The support structure 5 may additionally support the transmission 9 and / or the motor 10, in particular via the pinion 6.

[0044] The jacking assembly 4 comprises a transmission housing 11 enclosing the transmission 9 and configured to hold transmission fluid for the transmission 9 and to allow the pinion 6 and the motor 10 to connect to the transmission 9 from outside the transmission housing 11. The transmission housing 11 comprises a first housing section 11-1 proximal to the pinion 6 and a second housing section 11-2 more distal from the pinion 6. The first housing section 11-1 is formed by the support structure 5 and is indicated in figures using a dotted outline. One of the support positions Si is at a proximal axial end of the first housing section 11-1. The second housing section 11-2 is outside the support structure 5 and is indicated in figures using a dashed outline. The jacking assembly 1 is configured to transversely and / or axially fix the transmission 9 with respect to the second housing section 11-2. In the shown examples, the transmission 9 comprises a first transmission section 9-1 proximal to the pinion 6 and a second transmission section 9-2 more distal from the pinion 6. In the figures, a boundary or interface between the transmission sections 9-1, 9-2 is schematically indicated using a thin dashed line. The jacking assembly 4 is configured to inhibit exchange of transmission fluid between the first transmission section 9-1 and the second transmission section 9-2 within the transmission housing 11. The first transmission section 9-1 is mainly enclosed by the first housing section 11-1, wherein the second transmission section 9-2 is mainly enclosed by the second housing section 11-2. The first transmission section 9-1 and the second transmission section 9-2 are coupled to each other without transverse and / or axial play therebetween. The first transmission section 9-

[0045] I is coupled to the second housing section 11-2, at least via the second transmission section 9-2.

[0046] Returning to Fig. 3, the pinion unit 7 may optionally comprise a further pinion 6-F to be engaged with the leg-mounted rack 8, wherein the transmission 9 is further arranged to couple the further pinion 6-F to the motor 10 for driving the further pinion 6-F about a further pinion rotation axis RF parallel to the pinion rotation axis R, wherein the support structure 5 further supports the further pinion 6-F, wherein the transmission housing

[0047] II is further configured to allow the further pinion 6-F to connect to the transmission 9 from outside the transmission housing 11. Alternatively, the pinion unit may comprise only a single pinion, i.e. without a further pinion. Thus, in that case, a respective transmission and motor may be provided for each pinion.

[0048] In the examples of Figs. 5A to 7B, contrary to the known jacking assembly of Figs. 4A-B, the transmission housing 11 comprises a flexible third housing section 11-3 between the first housing section 11-1 and the second housing section 11-2. The third housing section 11-3 is configured to provide transverse and axial play between the first housing section 11-1 and the second housing section 11-2, and thereby between the transmission 9 and the support structure 5. The third housing section 11-3 can be formed from any suitable flexible material that can tolerate repeated deformation and contact with the transmission fluid, in particular while being impermeable to the transmission fluid. The third housing section 11-3 may be formed from an annular sheet of such material. As can be seen e.g. in Fig. 5C, in a neutral state, the annular sheet of material of the third housing section 11-3 is preferably shaped to extend along a curved cross sectional path having an axial range and a radial range, so that the third housing section 11-3 can expand and contract in axial direction and can also deform in transverse direction, preferably substantially without straining the material of the third housing section 11-3.

[0049] For clarity of the drawings, the transmission 9 is shown highly schematically, in particular substantially without details of the internals of the transmission 9. Such details are known as such and can be applied substantially without modification in the context of the present invention. In some cases, the design of the transmission 9 may be simplified in view of the advantages provided by the flexible third housing section 11-3 as described herein.

[0050] In the examples of Figs. 5A to 6B, the first transmission section 9-1 is coupled to the second housing section 11-2 not only via the second transmission section 9-2 but also independent from the second transmission section 9-2 via a transmission bearing 15, in particular so as to transversely and / or axially fix the first transmission section 9-1 with respect to the second housing section 11-2.

[0051] When assembling the jacking assembly 1, the third housing section 11-3 may be assembled to the first and / or second housing section 11-1, 11-2 while the support structure 5 supports the pinion 6. Thus, during installation, the pinion 6 may be mounted on the support structure 5 before the third housing section 11-3 is assembled to the support structure 5. In the examples of Figs. 5A to 6B, thanks to the aforementioned independent coupling, the second housing section 11-2, the transmission 9 and the pinion 6 may be installed together as one unit with respect to the support structure 5. Alternatively, e.g. in the example of Figs. 7A-B, the second transmission section 9-2 and second housing section 11-2 may be installed after the first transmission section 9-1 and the pinion 6 have been installed. In both cases, after the pinion 6, the first and second transmission sections 9-1, 9-2 and the second housing section 11-2 are positioned at their operational positions with respect to the support structure 5, the flexible third housing section 11- 3 can be assembled to complete the transmission housing 11, wherein the flexibility of the third housing section 11-3 can advantageously provide a level of tolerance.

[0052] In the examples of Figs. 5A to 7B, the jacking assembly 4 is configured to provide transverse and axial play between the transmission 9 and the first housing section 11-1 along an axial range bound by the support position Si that is at the proximal axial end of the first housing section 11-1.

[0053] In the examples of Figs. 5A to 7B, the third housing section 11-3 circumferentially surrounds the transmission 9, and the third housing section 11-3 axially spaces the second housing section 11-2 apart from the first housing section 11-1. Alternatively, or additionally, the third housing section may radially space the second housing section apart from the first housing section.

[0054] In the example of Figs. 6A-B, the transmission housing 11 comprises a rigid fourth housing section 11-4 between the first housing section 11-1 and the third housing section 11-3. The fourth housing section 11-4, here of a substantially cylindrical shape, is rigidly mounted to an outside of the support structure 5. Here, an axial size of the support structure 5 and the first housing section 11-1 has correspondingly been reduced compared to the example of Figs. 5A-D. In the examples of Figs. 5A to 7B, the jacking assembly 4 comprises a torque arm arrangement 12 for resisting rotation between the second housing section 11-2 and the first housing section 11-1 about the pinion rotation axis R.

[0055] In the examples of Figs. 5A-D and 6A-B, the torque arm arrangement 12 movably links the second housing section 11-2 to the first housing section 11-1, and the torque arm arrangement 12 axially bridges the third housing section 11-3. Here, as best seen in Fig. 5C, the torque arm arrangement comprises a link 16 hingingly connected to the second housing section 11-2 and the first housing section 11-1 at respective opposite ends of the link 16 using respective ball joints 17 arranged at different circumferential positions with respect to the pinion rotation axis R.

[0056] In the example of Fig. 7A-B, the torque arm arrangement 12 fixes a part of the transmission 9, in particular a part of the second transmission section 9-2, with respect to the first housing section 11-1 adjacent the third housing section 11-3 at several circumferential positions with respect to the pinion rotation axis R, wherein the circumferential positions together define a circumferential range C of less than 140 degrees. Here, the torque arm arrangement 12 comprises two tabs 13 extending radially outwardly from one or more stationary parts of the transmission 9, the tabs 13 being mounted to the support structure 5 internal of the transmission housing 11 during assembly.

[0057] The tabs 13 are arranged to be nearest a lateral side of the jacking assembly 1 where expected relative deformations between the transmission 9 and the support structure 5 are relatively small. Although a single tab arranged at said lateral side could already suffice as an effective torque arm arrangement, the set of two tabs 13 are more easily accessible during assembly in view of the possible obstruction by the second housing section 11-2. In Fig. 7 A, one of the tabs 13 can be seen partly through an opening in the second housing section 11-2, wherein a corresponding opening for the other tab 13 is obscured in the view of Fig. 7 A. Such openings may be provided to facilitate assembly of the tab 13 to the support structure 5 internal of the transmission housing 11. Thereafter, the openings can be closed off, e.g. with a respective lid, to prevent transmission fluid from flowing out of the transmission housing 11 through the openings.

[0058] Although such tabs 13 can limit the transverse and axial play provided by the flexible third housing section 11-3, the remaining play can still be sufficient to provide the advantages of the flexible third housing section 11-3 to a meaningful extent, in particular thanks to the limited circumferential range C allowing the tabs 13 to provide some level of flexion.

[0059] Although the invention has been explained herein using examples of embodiments and drawings, these do not limit the scope of the invention as determined by the claims. Within said scope, many variations are possible, as shall be appreciated by the skilled person having the benefit of the present disclosure. Examples thereof have been provided in the present disclosure. All such variants are considered included within the scope of the claims as determined by the claims.

[0060] LIST OF REFERENCE SIGNS

[0061] 1. Jack-up vessel

[0062] 2. Hull

[0063] 3. Leg

[0064] 4. Jacking assembly

[0065] 5. Support structure

[0066] 5-C. Common support structure

[0067] 6. Pinion

[0068] 6-F. Further pinion

[0069] 7. Pinion unit

[0070] 8. Rack

[0071] 9. Transmission

[0072] 9-1. First transmission section

[0073] 9-2. Second transmission section

[0074] 10. Motor

[0075] 11. Transmission housing

[0076] 11-1. F irst housing section

[0077] 11-2. Second housing section

[0078] 11-3. Third housing section

[0079] 11-4. Fourth housing section

[0080] 12. Torque arm arrangement

[0081] 13. Tab

[0082] 14. Pinion bearing

[0083] 15. Transmission bearing

[0084] 16. Link

[0085] 17. Ball joint

[0086] C. Circumferential range

[0087] R. Pinion rotation axis

[0088] RF. Further pinion rotation axis

[0089] Si, S2. Support positions

Claims

Claims1. Jacking assembly for a jack-up vessel, comprising: a pinion unit comprising a pinion to be engaged with a legmounted rack and a transmission arranged to couple the pinion to a motor for driving the pinion about a pinion rotation axis defining an axial direction of the jacking assembly; a support structure supporting the pinion; and a transmission housing enclosing the transmission and configured to hold transmission fluid for the transmission and to allow the pinion and the motor to connect to the transmission from outside the transmission housing, wherein the transmission housing comprises a first housing section proximal to the pinion and a second housing section more distal from the pinion, wherein the first housing section is formed by the support structure, wherein the second housing section is outside the support structure, characterized in that the transmission housing comprises a flexible third housing section between the first housing section and the second housing section, wherein the third housing section is configured to provide transverse and axial play between the first housing section and the second housing section.

2. Jacking assembly according to claim 1, wherein the third housing section circumferentially surrounds the transmission.

3. Jacking assembly according to claim 1 or 2, wherein the third housing section axially and / or radially spaces the second housing section apart from the first housing section.

4. Jacking assembly according to any of the preceding claims, comprising a torque arm arrangement for resisting rotation between the second housing section and the first housing section about the pinion rotation axis.

5. Jacking assembly according to claim 4, wherein the torque arm arrangement movably links the second housing section to the first housing section.

6. Jacking assembly according to claim 4 or 5, wherein the torque arm arrangement axially bridges the third housing section.

7. Jacking assembly according to any of the preceding claims, wherein the support structure supports the pinion at two axially spaced apart support positions along the pinion rotation axis, wherein the pinion is configured to engage the rack axially between the two support positions.

8. Jacking assembly according to claim 7, wherein one of the support positions is at a proximal axial end of the first housing section.

9. Jacking assembly according to claim 8, configured to provide transverse and axial play between the transmission and the first housing section along an axial range bound by the support position that is at the proximal axial end of the first housing section.

10. Jacking assembly according to any of the preceding claims, configured to transversely and / or axially fix the transmission with respect to the second housing section.

11. Jacking assembly according to any of the preceding claims, wherein the transmission housing comprises a rigid fourth housing section between the first housing section and the third housing section, in particular wherein the fourth housing section is outside the support structure.

12. Jacking assembly according to any of the preceding claims, wherein the pinion unit comprises a further pinion to be engaged with the leg-mounted rack, wherein the transmission is further arranged to couple the further pinion to the motor for driving the further pinion about a further pinion rotation axis parallel to the pinion rotation axis, wherein the support structure further supports the further pinion, wherein the transmission housing is further configured to allow the further pinion to connect to the transmission from outside the transmission housing.

13. Jacking assembly according to any of the preceding claims, further comprising the motor, wherein the motor is connected to the transmission for driving the pinion and preferably the optional further pinion.

14. Jacking assembly according to any of the preceding claims, wherein the transmission comprises a first transmission section proximal to the pinion and a second transmission section more distal from the pinion.

15. Jacking assembly according to claim 14, wherein the jacking assembly is configured to inhibit exchange of transmission fluid between the first transmission section and the second transmission section within the transmission housing.

16. Jacking assembly according to claim 14 or 15, wherein the first transmission section is mainly enclosed by the first housing section, wherein the second transmission section is mainly enclosed by the second housing section.

17. Jacking assembly according to any of claims 14 - 16, wherein the first transmission section and the second transmission section are coupled to each other substantially without transverse and / or axial play therebetween.

18. Jacking assembly according to any of claims 14 - 17, wherein the first transmission section is coupled to the second housing section independent from the second transmission section, in particular so as to transversely and / or axially fix the first transmission section with respect to the second housing section.

19. Jack-up vessel comprising at least one jacking assembly according to any of the preceding claims, wherein the respective support structure is supported on a hull of the jack-up vessel, wherein the respective pinion and optional further pinion are arranged to engage with a rack of a leg of the jack-up vessel.

20. Jack-up vessel according to claim 19, wherein the number of jacking assemblies of the at least one jacking assembly is at least two, preferably at least four, preferably wherein the jacking assemblies are arranged in pairs to engage with the rack from opposite lateral sides of the rack.

21. Method of performing jacking operations in a jack-up vessel according to claim 19 or 20, wherein the pinion and optional further pinionare driven to move raise or lower the leg with respect to the hull, wherein, during the driving, at a distance from the pinion, the transmission moves transversely and / or axially with respect to the support structure using the transverse and axial play.

22. Method of assembling a jacking assembly according to any of claims 1 - 18, wherein the third housing section is assembled to the first and / or second housing section, in particular while the support structure supports at least the pinion.

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