Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
  • F01D5/30—Fixing blades to rotors; Blade roots ; Blade spacers
  • F01D5/32—Locking, e.g. by final locking blades or keys
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
  • F01D5/30—Fixing blades to rotors; Blade roots ; Blade spacers
  • F01D5/32—Locking, e.g. by final locking blades or keys
  • F01D5/323—Locking of axial insertion type blades by means of a key or the like parallel to the axis of the rotor

Definitions

• the invention relates to an axial securing device for rotor blades of turbomachines through which axial flow flows, according to the preamble of patent claim 1.
• axial lock is known from US-A-2,928,651.
• a one-piece securing body made of sheet metal is used, the length of which is greater than the axial extension of the dovetail-shaped blade root or the opposite radial groove of the blade carrier.
• the end regions of the sheet which act as securing elements serve to absorb the axial forces, which protrude axially beyond the end faces of the blade root or the blade carrier and are bent in the radial direction for holding purposes.
• the first of the two protruding end regions is divided into two along the central longitudinal axis of the sheet.
• the two tabs thus emerging from the end region are bent in opposite radial directions for holding purposes in such a way that a first tab engages behind an end face of the blade carrier, while the second tab engages behind a first end face of the blade root.
• the second of the two protruding end regions is of this type in the assembled state bent over so that it engages behind a second end face of the blade carrier which is oriented opposite the first end face.
• a tongue protruding from the sheet metal plane in the middle of the sheet metal engages in a wedge-shaped recess in the blade root and also serves to absorb forces acting axially on the blade.
• the recess in the blade root is very complex and expensive to manufacture, since with the modern high-performance materials, such as nickel-based alloys or titanium alloys, which are used today for the manufacture of the blades, such recesses can only be produced by grinding or eroding.
• assembly and disassembly of axial locks with recesses in the blade root or in the radial groove of the blade carrier, into which a protrusion of the locking body then engages is usually complex and time-consuming.
• the end region protruding radially outwards, marked with 26, first has to be bent open.
• the securing body is formed in one piece from a sheet metal and its end regions as well as the spike-like tongue are produced by bending the sheet metal accordingly.
• the material of the sheet must be selected so that it can be bent into the required shape on the one hand and still absorb the forces that occur on the other.
• Such a / rather securing body can therefore only be designed to a limited extent for the possible shear and shear forces, with additional bending of the material being introduced by the bending.
• the known materials used may still barely meet the required properties, but at the high temperatures that occur in a high-speed turbomachine, such as in a turbocharger, it is hardly possible to find a material that is still at the high temperatures the necessary axial securing of the blades in the blade carrier is guaranteed. Furthermore, with such a fuse body, the end regions of the fuse bodies must be bent with high precision in order to fix the blades in their axial position exactly.
• an axial securing device with the features of claim 1, in which rotor blades of an impeller are secured by means of a securing body belonging to the axial securing device.
• the securing body has a first, axial end region and a second, axial end region, which are connected to one another via a connecting region.
• the connection area is arranged in a gap formed between the blade root end and the radial groove base.
• the first end region is designed such that it engages behind an end face of the blade root and the blade carrier on the flow outlet side.
• the second end region is designed such that it engages behind the end face of the blade carrier on the opposite side of the flow inlet.
• connection area has a spring element, with the aid of which, in the installed state, a radially acting force is introduced between the blade root and the radial groove base, which is sufficient to secure the rotor blade in its axial position against axial forces in the direction of flow entry.
• This configuration makes it possible to design the blade root as well as the radial groove without a radial recess, which considerably reduces the manufacturing costs.
• the securing body can simply be inserted into the radial groove and the blade can then be inserted into the radial groove with the blade root. Disassembly is just as easy in reverse order. No further manipulations such as bending or twisting the securing body or an end region of the securing body are necessary. This reduces the time required for assembly and disassembly.
• the spring element can be designed very simply in the form of a shaft in the connection area.
• the wave can be designed as a single solid wave, as a double or multiple wave, or as a half wave up or down. If the spring element is designed in the form of a wave-shaped bend in the connection area, the securing body is particularly easy to produce. But it is also possible to have the wave already when working out the fuse body from a block of material or when casting etc. into the fuse body so that subsequent bending is not necessary.
• the wave-shaped bending corresponds in its axial extent to approximately two to ten times the radial thickness of the connection area, since the best force ratios are achieved in the gap between the radial groove base and the blade root end.
• the force effect can be further improved.
• the fuse body is made of a high-temperature steel, it can also be used in high-speed turbo machines without any problems.
• the fuse body is made of a nickel-based alloy.
• Solid noses in the first and second end regions of the securing body ensure particularly good hold in the axial direction, since these cannot be bent open.
• Fig. 1 shows a part of a blade attached to a blade carrier and a
• FIG. 2 in a representation analogous to the representation in Fig. 1, a second embodiment of the axial lock according to the invention
• FIG. 3 in a representation analogous to the representations in Fig. 1 and 2, a third
• FIG. 4 in a representation analogous to the representations in Fig. 1 to 3, a further embodiment of the axial lock according to the invention.
• Figures 1 and 2 each show part of a moving blade 10 with a fir tree-shaped blade root 12, which is held in a fir tree-like radial groove 14 of a blade carrier 16.
• a securing body 22 of the axial securing device 20 according to the invention is arranged in a gap 18 between the end 13 of the blade root 12 and a radial groove bottom 15 of the radial groove 14 and is formed in one piece in the examples shown.
• the direction of flow of the working medium acting on the blades 10 is identified by an arrow A in each case. Contrary to this flow A, smaller axial forces act in direction B on the blades 10 in relation to the force acting through the flow A.
• the axial securing device 20 according to the invention ensures a precise hold of the blades 10 in their axial position against both forces A, B.
• the fuse body 22 which is preferably formed from a nickel-based alloy, such as Nimonic 90, has two end regions 26, 26 'and 28 with which the securing body 22 projects beyond the axial extent of the radial groove 14 of the blade carrier 16 or that of the blade root 12.
• the first end region 26, 26 'of the securing body 22 is designed in the form of a solid double nose.
• a second end region 28 is arranged which, in the assembled state, engages radially on the inside on an end face 34 of the blade carrier 12 on the flow inlet side.
• the two end regions 26, 26 'and 28 are axially connected to one another by a connecting region 36.
• the connecting region 36 has a rectangular cross section with dimensions that are approximately constant over its entire axial length. This enables a very simple manufacture of the securing body 22 and a simple machining of the blade carrier 16 and the blade root 12. However, all other types of cross sections, such as semicircular, polygonal shapes, etc., are also conceivable.
• connection area 36 in FIG. 1 has a spring element 38 in the form of a simple shaft 40 of the connection area 36 on the flow outlet side.
• This simple shaft 40 has approximately two and a half times the axial extent (not shown to scale) in relation to the radial thickness of the connecting region 36.
• the shaft 40 can be produced from a block of material during casting or when punching out, milling out or cutting out with a laser but when using materials that allow bending or deep drawing, by appropriate deformation of the connection area. In the latter two methods, the cross section in the region of the shaft 40 can be somewhat reduced in relation to the otherwise approximately constant cross section of the connecting region 36.
• the connecting area 36 of the securing body 22 shown in FIG. 2 also has a shaft as a spring element 38, which is designed as a half shaft 42 and, in contrast to the shaft 40 in FIG. 1, is arranged on the flow inlet side.
• the gap 18, securing body 22 and spring element 38 are not shown to scale for better visibility.
• the radial expansion of the gap 18 between the blade root end 13 and the radial groove base 15 corresponds approximately to the radial thickness of the connecting region 36.
• the embodiments in FIGS. 3 and 4 differ from the previous ones in that the blade root 12 'and the radial groove 14' are dovetail-shaped.
• the spring element 38 is in turn designed as a shaft on the flow exit side, in FIG.
• FIGS. 3 and 4 are designed differently and show, by way of example, that the axial lock 20 according to the invention can be used in all conceivable blade root and radial groove shapes, as long as the blade root 12 and radial groove 14 have a groove.
• Form a spring connection in such a way that a securing of the blade 10 in the radial direction and in the circumferential direction is ensured.
• the axial lock 20 according to the invention corresponds in principle to that as shown in FIG. 1.
• the end regions 26, 26 'and 28 are produced in a known manner by bending and instead of a simple shaft or a double shaft, a multiple shaft 48 is arranged approximately axially in the middle of the connecting region 36.
• the blade root 12 is in frictional contact with the connecting region 36 of the securing body 22 in the case of the spring elements 38 configured as simple shafts 40, double shaft 45 or multiple shafts 48 on both sides of the shafts 40, 45, 48.
• the spring elements 38 configured as simple shafts 40, double shaft 45 or multiple shafts 48 on both sides of the shafts 40, 45, 48.
• the design of the spring element 38 as a half-shaft 42 or a half-shaft 44 means that the blade root 12 is in frictional contact with the connecting region 36 of the securing body 22 only on one side of the shaft 42, 44 and, if necessary, with several shaft arches with one or a plurality of wave arches 46, as shown in FIG. Instead of half waves and one and a half times waves, two and a half, three and a half times, etc. waves can be provided.
• the axial extent of the shaft irrespective of how it is designed in detail, whether as a half-wave, a simple shaft or a multiple shaft, can be in the range from approximately two to ten times the radial thickness of the connecting region 36.
• the securing body 22 is inserted into the radial groove 14 in such a way that the end regions 26 'and 28 engage behind the two end faces 30, 34 of the blade carrier 16.
• the rotor blade 10 is then inserted radially above the securing body 22 into the radial groove 14, the radially acting force introduced by the spring element 38, which is noticeable as frictional resistance, having to be overcome.
• the rotor blade is pushed into the radial groove 14 until its end 32 on the flow outlet side is brought into abutment with the radially outer nose 26 'of the first end region 26, 26'.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)
• Turbine Rotor Nozzle Sealing (AREA)

Applications Claiming Priority (3)

Publications (1)

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ID=29555530

Family Applications (1)

Country Status (5)

Families Citing this family (9)

Family Cites Families (10)

• 2003
  • 2003-05-06 CN CNB038118467A patent/CN100335749C/zh not_active Expired - Fee Related
  • 2003-05-06 AU AU2003226999A patent/AU2003226999A1/en not_active Abandoned
  • 2003-05-06 EP EP03755068A patent/EP1507958A1/de not_active Withdrawn
  • 2003-05-06 WO PCT/CH2003/000289 patent/WO2003100220A1/de not_active Application Discontinuation
  • 2003-05-06 KR KR10-2004-7018850A patent/KR20050004188A/ko not_active Application Discontinuation

Non-Patent Citations (1)

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