GB2393493A

GB2393493A - Conical fastening arrangement

Info

Publication number: GB2393493A
Application number: GB0222453A
Authority: GB
Inventors: Graeme John Poole
Original assignee: Rolls Royce PLC
Current assignee: Rolls Royce PLC
Priority date: 2002-09-27
Filing date: 2002-09-27
Publication date: 2004-03-31
Also published as: GB0222453D0

Abstract

A fastening arrangement 142 comprises first and second co-operable fastening members 146, 150 each having a conical face 148, 152 to engage the conical face 152, 148 of the other fastening member. The fastening arrangement further includes locking means 168 to lock the first and second fastening members in engagement with each other. The arrangement may comprise third and fourth fastening members 154, 158 each having a conical face 156, 160 to engage the conical face 160, 158 of the other fastening member. The first fastening member 146 may be a split ring that is deformable to accommodate the movement generated by tightening the locking means 168.

Description

1 2393493

Fastening Arrangement This invention relates to fastening arrangements. More 5 particularly, but not exclusively, the invention relates to fastening arrangements for use in fastening together shaft segments to form a single shaft, for example in gas turbine engines. When assembling certain joints in a gas turbine engine, 10 for example the shaft segments of a shaft interconnecting a turbine with a compressor, it is necessary for them to be tight for functional reasons. Some prior art connections

use interference fits, but these require differential temperatures and may also need specialized press tools to 15 assemble. Disassembly also requires specialized tools and carries with it the risk of damage to the engaging surfaces.

Moreover, the fact that specialized tooling is required prevents "blind" assembly which may encourage the use of looser fits. An associated disadvantage of this is that the JO functionality could be impaired and that there is a higher risk of wear.

According to one aspect of this invention, there is provided a fastening arrangement for fastening together two components, said arrangement comprising first and second 25 cooperable fastening members, each of said first and second fastening members having a conical face to engage the conical face of the other fastening member and the fastening arrangement further including locking means to lock the first and second fastening members in engagement with each 30 other.

Preferably, the arrangement further comprises third and fourth cooperable fastening members, each of said third and fourth fastening members having a conical face to engage the conical face of the other of the third and fourth fastening 5 members whereby the locking means locks the first and second fastening members in engagement with each other and thereby

locks the third and fourth fastening members in engagement with each other.

Preferably, the conical faces are frusto-conical.

Each fastening member is preferably annular in 5 configuration.

In some embodiments, each component has at least one fastening member fixedly mounted thereon. Conveniently, where a fastening member is fixedly mounted to a component, it is integral with the component.

10 Preferably, the first fastening member is movable relative to its respective component to cooperably engage the second fastening member. Preferably, the locking means is arranged to engage said first fastening member and to effect said movement of the first fastening member.

15 The first fastening member is preferably deformable ircumferentially to accommodate said movement, conveniently the first fastening member is in the form of a split ring, preferably having a radially extending gap defined by opposed ends spaced from each other. On Lightening of the So ior-kina means onto the first fastening member, the aforesaid oppose- ends may be moved towards each other, thereby t-ighterllrlg the fastening members to one another.

In some embodiments, at least one of the second, thir or fourth fastening members may be separate from the 95 omporqents. In such embodiments, the, or each, respective :mporlet has a holding member, which may be integral ierewi,h, to hold the fastening member thereon.

Leniently, the first and second fastening members -A ai..lly spaced from the third and fourth fastening 30,!r:---s. 1 e locking means may comprise a nut which may be i y receivable on one of the components to engage --at fastening member. The locking means may engage ---sit fastening member to push said first fastening 5 to tight engagement with said second fastening !

According to another aspect of this invention, there is provided a fastening assembly, comprising first and second components to be fastened together, and a fastening arrangement as described above.

SThe components may comprise components of a gas turbine engine, for example components forming a shaft of a gas turbine engine. The components may be shaft segments.

According to another aspect of this invention there is provided a gas turbine engine incorporating a fastening 10 assembly as described above.

Embodiments of the invention will now be described by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a sectional side view of the upper half of a IS gas turbine engine; Fig 2 is a sectional side view of an upper part of a shaft of the gas Lurbine engine known in Fig It Fig 2A is a view of part of a first fastening member for use in a fastening arrangement used in the shaft Fig. 2; SO Figs. 3-8 are sectional side views of an upper part of different versions of shafts of a gas turbine engine shown in Fig. 1.

With reference to Fig. 1, a ducted fan gas turbine engine generally indicated at 10 has a principal axis X-X.

" The engine 10 comprises, in axial flow series, an air intake 11, a propulsive fan 12, a compressor region 113 comprising an intermediate pressure compressor 13, and a high pressure compressor 14, combustion means 115 comprising a combustion 15, and a turbine region 116 comprising a high pressure :() turbine 16, an intermediate pressure turbine 17, and a low pressure turbine 18. An exhaust nozzle 19 is provided at the tail of the engine 10.

The gas turbine engine 10 works in the conventional manner so that air entering the intake 11 is accelerated by s the fan to produce two air flows: a first air flow into the in ermediate pressure compressor 13 and a second air flow

which provides propulsive thrust. The intermediate pressure compressor 13 compresses the air flow directed into it before delivering the air to the high pressure compressor 14 where further compression takes place.

5 The compressed air exhausted from the high pressure compressor 14 is directed into the combustion 15 where it is mixed with fuel and the mixture combusted. The resultant hot combustion products then expand through, and thereby c-drive the high, intermediate and low pressure turbine 16, 17 10 and 18 before being exhausted through the nozzle 19 to provide additional propulsive thrust. The high, intermediate and low pressure turbines 16, 17 and 18 respectively drive the high and intermediate pressure compressors 14 and 13 and the fan 12 by suitable 15 interconnecting shafts 118. Each of the shafts connecting the respective turbines with the respective compressors is formed of a plurality of shaft segments which are axially :oupled together.

Referring to Fig. 2, there is shown a sectional side so view of the upper region of two components forming one of the Shafts interconnecting a turbine with the respective crnpressor. The shaft is designated 120 and is annular in :rti<-luration. The shaft 120 comprises two annular shaft egmerlts 130, 132. The first shaft segment 130 comprises a 95;-irs: annular coupling member 134, and the second shaft segment 132 comprises a second annular coupling member 136.

Thee -coupling members 134, 136 overlap each otter, as shown, -ouple the two shaft segments 130, 132 together. The --;. Coupling member 134 has a circumferentially extending 30 -i..'ly outer face 135 facing the second coupling member Wines 138, 140 are provided to prevent r;-rential rotation of the coupled shaft segments 130, lit- ive to each other. The coupling members 134, 136 35 -hereby, the shaft segments 130, 132 are fastened -!by a fastening arrangement 142 which comprises

first and second fastening members 146, 150 and, axially spaced therefrom, third and fourth fastening members 154, 158. The first fastening member 146 has a frusto-conical 5 conical face 148, the second fastening member 150 comprises a corresponding frusto-conical face 152. The faces 148, 152 are arranged to engage each other in use as shown.

The third fastening member 154 has a frusto-conical conical face 156, and the fourth fastening member 158 has a 10 frusto-conical face 160, corresponding to the frusto-conical face 156. The faces 156,160 are arranged to engage each other in use, as shown The fastening member 146 is separate from, and moveable relative to, the first and second coupling members 134, 136.

IS The first fastening member 146 is in the form of a split ring, which is of an annular configuration and has a radially extending gap 162 (see Fig. 2A) through it.

Referring to Fig 2A, a part of the first fastening member 146 in the vicinity of the gap 162 is shown in which it can 20 be seen that it has opposed ends 164,166. The opposed ends 164, 166 are spaced from each other to define the gap 162.

The fastening member 146 has a radially inner face 163.

The fastening arrangement also includes a locking means in the form of a clamp nut 168 having threads 170 to 25 threadably engage corresponding threads 172 on the first coupling member 134.

Wherl the clamp nut 168 is threadably engaged onto the first coupling member 134, it engages the first fastening member 146, and tightening of the clamp nut 168 onto the 30 first coupling member 134 pushes the first fastening member 146 into tight engagement with the second fastening member 150. During such tightening the respective conical faces 148, 152 of the first and second fastening members 146, 150 slide relative to, and are tightened against, each other.

35 In the embodiment shown in Fig. 2, the first fastening member 146 slides radially inwardly. This movement is

accommodated by the movement towards each other of the opposed ends 164, 166 at the gap 162 in the first fastening member 146. Thus, the tightening of the clamp nut 168 pushes the first and second fastening members 146, 150 5 against each other, and also pushes the third and fourth fastening members 154, 158 against each other. As a result, the first and second coupling members 134, 136 are fastened to each other and hence the shaft segments 130, 132 are fastened together.

IO The first fastening member 146, is coated wit- a friction reducing coating, for example a dry film lubricant.

Tic coating allows the first fastening member 146 to slide easily along first coupling member 134 when the clamp nut 168 is tightened against the first fastening member -46.

15 The coating also allows the respective conical faces -48, 152 to slide easily against each other in the radially inward direction. Final locking of the first and second fastening members 146, 150 with each other and of the third ?1Ci fourth fastening members 154, 158 with each other oc urs 90 ';1t-rt-2!2 the inner face 163 engages the radially outer face 135 of- the second coupling member 134. This ensures Concentricity of the first and second shaft segments:30, :'. In ttliS position, there is still a small gap 16^ in he first- fastening member 14G.

05 Referring to Fig. 3, there is shown another embodiment, :'ih 'I Ah its similar to Fig. 2, and the same features have been Ace- Donated with the same reference numeral. The embodiment t'''',.'!1 in Fig. 3 differs from that shown in Fig. 2 in that, it: the embodiment shown in Fig. 2, the conical faces _52, 30 2 i' Of the second and fourth fastening members are pro:--ded -',e end of the splice 140 of the second coupling member Edith the embodiment shown in Fig. 3, the conical faces 2<0 of the third and fourth conical members 150, 158 ->m-:e from the splice 140.

5 smith the embodiment shown in Figs. 2 and 2A, the ;tening member 146 in Fig. 3 is in the form of a

split ring and has a configuration shown in Fig. 2A.

Fig. 4 shows a further embodiment, which, again, comprises many of the features shown in Fig. 2, and these have been designated with the same reference numerals. In 5 the embodiment shown in Fig. 4, the first and second fastening members 146, 150 are the same as shown in Fig.3, and the fourth fastening member 158 is the same as shown in Fig. 2. The third fastening member 154 is separate from the first coupling member 134 and is in the form of an annular 10 split ring having a radially inner surface 175 to engage the second coupling member 132.

A holding member 174 is provided integrally on the first coupling member 134 to provide coupling engagement between the third fastening member 154 and the first IS coupling member 134. A spacer 176 is provided between the third fastening member 154 and the holding member 174. The spacer 176 is of an annular configuration and is in the form of a split ring. Its axial length between the third fastening member 154 and the holding member 174 determines SO the extent of overlap between the first and second coupling member 134, 136.

The third fastening member 154 and the spacer 176 are in the form of split rings to facilitate fitting them onto the second coupling member 134 over the splices 140.

IS Fig. 5 shows a further embodiment which, again, possesses many of the same features as shown in Fig. 2, and these have been designated with the same reference numeral.

The first and second fastening members 146, 150 shown in Fig. 5 are generally the same as shown in Fig. 3. The 30 embodiment shown in Fig. 5 differs from the embodiment shown in Fig. 3 in that the third fastening member 154 is integral with the first coupling member 134, the fourth fastening member 158 is in the form of an annular split ring having a radially outer surface 178 to engage the first coupling 35 member 136.

The second coupling member 136 comprises a holding

member 180 at the end Of the splines 140. A spacer 182 extends between the fourth annular member 158 and the stop member 180. Again, the axial length of the spacer 182 determines the extent c overlap of the first and second 5 coupling members 134, 1<. The spacer is in the form of a split ring.

The fourth fastenir.- member 158 and the spacer 182 are both in the form of split rings to allow them to be fitted onto the first coupling Member 132 over the splices 138.

10 In the case of the embodiment shown in Fig. 6, this is similar to the embodime:- shown in Fig. 5, but differs in that although the first fastening member designated 346 is the same as shown in Fig. 5, it is held in place on the second coupling member '6 by a radially inwardly extending IS holding member 186 provided integrally on the second coupling member 136. T:-e first fastening member 346 shown in Fig. 6 operates in -:e same way as the first fastening member 146 shown in Firs. 2 to 5. The first fastening member 346 of Fig. 6 is 'nerd in place by the holding member 20 'S6 on the second coupling member 136, instead of being redivided on the first cc;cling member 134.

Figs. 7 and 8 show- further modifications which again !mprise many of the f=-.tures of the embodiments shown in gs. 2 to 5, and these have been designated with the same 9 Difference numeral. Ir. these embodiments, the third and faur-th coupling members '54, 158 are generally similar to -jut shown in Figs. 4 ard 5.

In the embodiment unsown in Fig. 7, the second coupling fiber 136 has a radially inwardly extending annular lug 30 -antler 188 to which is -. tached a further annular extension --abler 189 so that an an:-ular recess 190 is defined between -.,ond coupling memL-_- 136 and the extension member 189.

: -st coupling membe- 134 is received in the recess 190.

: ' embodiment, a rst annular fastening member 446, 3- a frusto-conica_ face 448, is provided on the : fin member 189 and is secured thereto bv a bolt 189A,

although any other suitable securing means could be used.

The first fastening member 446 is in the form of a split ring as described above. A second annular second fastening member 450 is provided integrally at the free end of the 5 first coupling member 134. The second fastening member 450 has a frusto-conical face 452. The conical face 448 of the first coupling member 446 engage the conical face 452 of the second coupling member 450.

The end of the extension member 189 overlapping the 10 first coupling member 134 has threads 192, which engage corresponding threads 470 of a clamp nut 468.

The clamp nut 468 is threadably received on the extension member 189 and is tightened thereon to push the first fastening member along the extension member towards 15 the second fastening member 450 until the frusto-conical faces 448, 452 engage each other. Further tightening of the clamp nut 468 against the first fastening member 446 causes the first fastening member 446 to move radially inwardly until sufficient tightness is achieved.

2() The embodiment shown in Fig. 8 is similar to that shown in Fig. 7 and the same features have been designated with the same reference numerals. However, the embodiment shown in Fig. 8 differs from that shown in Fig. 7 by the construction of the clamp nut, designated 568 in Fig. 8.

25 The second coupling member 134 has a radially inwardly extending threaded lug 288 having threads 289 on the radially inner surface thereof. The threads 289 engage corresponding threads 570 on the clamp nut 568. The clamp nut 568 extends across the second coupling member 136 to 30 define a recess 390 therebetween.

The end region of the first coupling member 134 is received in the recess 390. The clamp nut 568 has a radially outwardly extending flange 572 which engages the first fastening member 446 when the clamp nut 568 is 5 tightened onto the lug 288 to pull the first fastening member 446 into engagement with the second fastening member

450 so that the frusto-conical faces 448, 452 slide against each other as the clamp nut 568 is tightened, in a similar way to that described above with reference to Fig. 7.

There is thus described a simple and effective 5 arrangement for fastening together various components, and particularly shaft segments of a shaft of a gas turbine engine, and the embodiments above provide several advantages. For example, there is significant ease of assembly over prior art couplings. Moreover, the only

10 tooling required is a standard spanner or socket and there is no building or stripping damage.

Various modifications can be made without departing from the scope of the invention, for example other arrangements of components and first and second pairs of IS fastening members can be used.

Whilst endeavouring in the foregoing specification to

draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable SO feature or combination of features hereinbefore referred to nd/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

Claims

1. A fastening arrangement for fastening together two components, said arrangement comprising first and second 5 cooperable fastening members, characterised in that each of said first and second fastening members has a conical face to engage the conical face of the other fastening member and the fastening arrangement further includes locking means to lock the first and second fastening members in engagement 10 with each other.

2. A fastening arrangement according to claim 1, characterised in that the arrangement further comprises third and fourth cooperable fastening members, each of said third and fourth fastening members having a conical face to 15 engage the conical face of the other of the third and fourth fastening members whereby the locking means locks the first and second fastening members in engagement with each other and thereby locks the third and fourth fastening members in engagement with each other.

20 3. A fastening arrangement according to claim 1 or 2, characterised in that the conical faces are frusto-conical.

4. A fastening arrangement according to claim 1, 2 or 3, characterised in that each fastening member is annular in configuration. 5 5. A fastening arrangement according to any preceding claim, characterised in that each component has at least one fastening member fixedly mounted thereon.

6. A fastening arrangement according to claim 5, characterised in that the fixedly mounted fastening member 30 is integral with the component.

7. A fastening arrangement according to any preceding claim, characterised in that the first fastening member is movable relative to its respective component to cooperably engage the second fastening member, and the locking means is 5 arranged to engage said first fastening member and to effect said movement of the first fastening member.

8. A fastening arrangement according to claim 7, characterized in that the first fastening member is deformable circumferentially to accommodate said movement.

9. A fastening arrangement according to claim 8, 5 characterized in that the first fastening member is in the form of a split ring, preferably having a radially extending gap defined by opposed ends spaced from each other, whereby on tightening of the locking means onto the first fastening member, the aforesaid opposed ends are moved towards each I() other, thereby tightening the fastening members to one another. 10. A fastening arrangement according to claim 2, characterized in that the first and second fastening members are axially spaced from the third and fourth fastening IS members.

11. A fastening arrangement according to any preceding claim, characterized in that the locking means comprises a nut which is threadably receivable on one of the components lo engage said first fastening member, the locking means 2() being formed to engage said first fastening member to push said first fastening member into tight engagement with said second fastening member.

L2. A fastening assembly, comprising first and second -omponerlts to be fastened together, characterized by a L-asterling arrangement according to any preceding claim.

13. fastening assembly according to claim 12, inaracterised in that the components comprise shaft segments :i*- a shaft.

1l. A fastening assembly according to claim 12 or 13, 3() ':araGterised in that the components comprise components of --; turbine engine.

A gas turbine engine incorporating a fastening assembly Outing to any of claims 12 to 14 above.

fastening arrangement substantially as herein i-:bed with reference to any of Figs. 2 to 8 of the --if -:nying drawings.

17. A fastening assembly incorporating a fastening arrangement according to claim 16.

18. A gas turbine engine incorporating a fastening assembly according to claim 17.

5 19. Any novel subject matter or combination including novel subject matter disclosed herein, whether or not within the scope of or relating to the same invention as any of the preceding claims.