JP4315801B2 - Fixed system for axial flow turbomachinery blades - Google Patents

Description

  The invention relates to an axial fixing system for a rotor blade of an axial-flow turbomachine according to the upper concept of claim 1 and to a fixing body for the fixing system according to the superordinate concept of claim 8.

  Centrifugal force acts on the rotor blades of the axial flow turbomachine based on the rotation. These forces are usually received by a groove-spring connection between the blade and the blade carrier, which is arranged in the radial direction and extends axially, in the shape of an oak tree or an oak tail. On the other hand, the axial force generated through the axial flow direction of the flow medium must be received by a separate fixing device.

  In order to fix the wing in the axial direction, a fixed body is usually used which is arranged in a radial gap between the tip of the wing and the bottom of the axial groove.

  This is, for example, a fixed body that extends from the end arranged downstream to the axial groove part arranged in the radial direction, as is known from US Pat. These fixtures generally comprise a protrusion disposed upstream, which engages into an associated groove in the wing foot. The end region located downstream projects beyond the axial groove, and this end region grips the back side of the blade carrier located downstream from behind in order to fix the rotor blade in the axial direction. Can be folded. The projecting portion of the wing foot grips the pressure side of the wing carrier from the back at the end portion of the wing foot facing each other.

  Other fixtures used for axial fixation extend over the entire length of the axial groove and project on both sides beyond this axial groove. This is described in Patent Document 2 and Patent Document 3, for example. In the case of the fixed body described in Patent Document 3, one protruding end region is formed as a shoulder-type protruding portion that grips the pressure side of the blade carrier from behind, whereas the other protruding end The partial region is brought into a position where the end surface of the blade carrier located downstream is gripped from behind by being folded in the assembled state. The fixed body disclosed in Patent Document 2 is made of a thin plate, and both end regions projecting from the fixed body are bent so that both end surfaces of the blade carrier are gripped from behind with these end regions being incorporated. It is formed to do. In both cases, the joint with the wing foot that supports in the axial direction is formed by a protrusion or tongue, which protrudes from the respective fixed body and has a corresponding wing foot. Engage in the groove.

The manufacture of the described stationary body is expensive. This is because, on the one hand, the material must be chosen so that it can be bent into the required shape, but nevertheless absorb the forces that occur. On the other hand, in order to accurately fix the blade at its axial position, the end region of the thin plate must be bent with high accuracy. Such a fixture can only be designed conditioned on the possible thrust and shear forces, in which case bending results in additional material weakening. Thus, for the very high rotational speeds applied today, the folded end will always be unable to withstand the load and will be spread by a large force. The wing is displaced from its position in the axial direction and rubs against the housing.
US Pat. No. 2,641,443 US Pat. No. 2,928,651 British Patent No. 643, 1914

  Accordingly, it is an object of the present invention to provide a fixed for a blade of an axial flow turbomachine that is easy to manufacture and assemble, which absorbs axial thrust and shear forces reliably and holds the blade in place. Is to provide a system.

  These problems are solved by the fastening system according to the features of claim 1.

  According to the invention, the fixing system for each blade comprises an axial groove arranged in the radial direction in the blade carrier, in which the blade is matched to its counterpart. It can be inserted by the wing foot part formed in. A fixed body is disposed between the wing foot end and the axial groove bottom, and this fixed body is located in the first end region of the wing carrier and faces the acting axial force. Grip the back of the back from behind. The fixing element formed integrally with the wing carrier is arranged axially adjacent to the first end region of the fixed body and constitutes an axial stopper for this fixed body To do. The first end region of the stationary body will be located in a circumferential groove between the stopper and the blade carrier. The stopper avoids that the fixed body is displaced from its position in the axial direction due to the force generated by the fixed body or that the end region is widened, so that the blades and the blades are accurately moved by the blades. The position is kept. By integrally forming the wing carrier and the fixing element, manufacture and assembly are particularly simple and cheap.

  The simplest is that the fixing element formed integrally with the wing carrier can be manufactured by lathing and / or milling, and if the material is expensive, it can be manufactured by polishing.

  In this fixing system, a fixed body that projects axially beyond the axial groove in both end regions and grips one end face of the wing carrier from the rear in the state in which the end regions are incorporated. It is particularly simple and inexpensive to work with. This has the advantage that the wing foot can be easily formed. This is because the wing foot portion does not need to grip the wing carrier from behind on the pressure side. However, it is also possible to use a rotor blade having a stationary body that extends only over a part of the axial groove from the downstream end and a blade foot that is shaped to be suitable for this stationary body.

  When the end region of the fixed body is wider than the base portion of the fixed body connecting these end regions, the force acting on the end region is distributed to a large surface. This favors the ratio of forces per surface associated with the stopper attached to the end region constituted by the fixing element.

  If the end region of the fixed body is wider than the base portion and wider than the axial groove, the end region of the fixed body projects from the base portion radially outward with the assembled end region. It is very advantageous to grip the end face of the part and the end face of the blade carrier from behind. This is the case when no additional tongues and protrusions that engage into the appropriate grooves in the wing foot are required to form the connection between the wing foot and the stationary body. This facilitates the manufacture of the wing foot and the manufacture of the stationary body. Such a fixing body according to the invention is of course not only associated with the fixing system according to the invention, but can also be used without a fixing element in place of a known fixing body.

  If the fixing element is manufactured as an independent fixing disk or fixing ring, this fixing ring is then welded or glued to an object that is integral with the wing carrier, but current turbomachines use a fixing system. Can be enhanced.

  Another advantageous form of the invention is the subject of the other dependent claims.

  In the following, the subject of the present invention will be described in detail on the basis of the exemplary embodiment illustrated in the accompanying drawings.

  The symbols used in the drawings and their meanings are listed together in a symbol list. Basically, the same parts in the figures have the same reference numerals.

  FIGS. 1 and 3 each show one blade 10 which, in its twelve portions, is fixed in an axial groove 14 of a radially arranged blade carrier 16. For reasons of better understanding, only a part of the wing carrier 16 is shown in the cross-sectional view relative to the axial groove 14. The wing foot 12 is formed as a foot of an oak tree, and the axial groove 14 is formed as a groove suitable for the other party. Therefore, the wing foot 12 is grooved in the radial direction and the circumferential direction. The anchor is fixed so that there is no displacement in 14. In order to fix in the axial direction, a fixed body 22 is disposed between the wing foot end portion 13 belonging to the wing foot portion 12 and the axial groove bottom portion 15 that restricts the axial groove 14 radially inward. Both end regions 26, 26 ′ of this fixed body protrude beyond the axial groove 14 in the axial direction. As can be seen from FIG. 2, both end regions 26, 26 ′ are wider than the base portion 28 of the fixed body 22 that connects these end regions. In the assembled state, the end regions 26, 26 ′ project radially outward from the base portion 28, respectively, and end surfaces 38 ′, 40 ′ of the wing foot 12 and end surfaces 38, wing carrier 16, respectively. Grasping 40 parts from behind. Due to the fact that the end regions 26, 26 ′ of the fixing body 22 are wider than the base portion 28 and wider than the axial groove 14, these end regions are formed so that these end regions are radially outward. Even when projecting from the portion 28, the portions of the end faces 38, 40 of the blade 16 are gripped from behind.

  The first end face 38 of the blade carrier 16 constitutes a pressure side of the blade carrier 16. A very large axial force acts on this side based on the flow direction A (see arrow). This axially acting force via the wing foot 12 is also transmitted to the first end region 26 of the stationary body 22, which end region 40-the end face 40-the back side 40 of the wing carrier located facing each other. It is said that-is gripped from behind. In order to avoid widening the first end region 26, a fixing element 24 is arranged on the back side 40 of the wing carrier 16 and this fixing element is axially downstream in the first end region. The first end region 26 can no longer be widened. The fixing element 24, together with the fixing body 22, the axial groove 14 and the blade foot 12, constitutes a fixing system 20, which makes the blade 10 axial, radial, even at very high rotational speeds. In addition, the position in the circumferential direction is reliably coupled to the blade carrier 16. In the example shown, the fixing body 22 is formed from a thin plate and both end regions 26, 26 ′ are brought into their position protruding from the base portion 28 radially outward by folding. It is. Of course, the first end region that grips the back side 40 of the wing carrier from behind can, however, also be formed as a solid protrusion, only the second end region 26 ′ being positioned by folding. Can bring in.

  3 and 4 show that the fixing element 24 is formed integrally with the wing carrier 16. In the production of this integrated embodiment, the axial groove 14 is first milled or broached into the base of the blade carrier 16. Next, the backside 40 of the wing carrier 16 is turned with a stripe that does not have to be approximately twice as thick as the fixed body 22, and the remaining shoulder portion extends beyond the axial groove bottom 15 and has a radius. As long as it protrudes radially inward somewhat more than the first end region 26 of the fixed body 22 protruding outward in the direction, it is turned radially inward. Finally, on the side of the current shoulder facing the axial groove 14, lathe processing provides a circumferential groove 42 that extends radially inward substantially beyond the axial groove bottom 15. The width is dimensioned so that this width can accommodate the first end region 26 of the stationary body 22 with little play. For example, if a very expensive material such as Nimonic® 901 containing about 40% nickel is used, the circumferential groove 42 may be formed by polishing. Due to this measure, downstream of the circumferential groove 42, the incisions produced by milling the axial groove 14 and the elements remaining between them remain in the shoulder portion that was originally turned. . The remaining elements each constitute an axial stop 34 for the first end region 26 of the fixed body 22, which certainly extends beyond the axial groove 14 based on its width. Therefore, it protrudes beyond the notch, so that the stopper can exert its action. The axial extent of each wing foot 12 and the base portion 28 of each fixed body 22 corresponds to the axial extent of the axial grooves 14 remaining after lathe machining, and therefore, after assembly, no matter what Neither the wing foot 12 nor any portion of the base portion 28 protrudes into the circumferential groove 42 or beyond the pressure side 38 of the wing carrier.

  The fixing element 24 can be combined with an arbitrarily formed fixing body, in which case it constitutes the fixing system 20 according to the invention. In this case, there is no problem with the corresponding fit of the circumferential groove 42.

  However, the fixing element 24 can also be formed as an independent fixing disk 32, as shown in FIG. 1, which is integrated, for example, by means of a welded connection 30 with the wing carrier 16. Can be connected to an object. In this case, the fixed disk 32 is provided with a shoulder portion on the side facing the wing carrier 16, and this shoulder portion is provided with a circumferential groove 42 when coupled to the wing carrier 16. Each first end region 26 of the stationary body 22 for the rotor blade 10 engages. Depending on the configuration of the wing carrier 16, the fixing element 24 can also be formed as a fixing ring. Instead of using a welded connection 30, it is also conceivable to connect the fixing element 24 to an integral object by adhesive bonding with the wing carrier 16.

  In an independent form of the fixing element 24, the current wing carrier 16 can be augmented by an axial groove / fixture-joint with this fixing element 24 and can be coupled together with the fixing element into an integral object. It is advantageous. In this way, the fixation system 20 according to the invention can be installed later. This is possible without depending on the form of the stationary body. This is because the fixing system 20 works with other fixing bodies as known from the patent literature mentioned at the beginning, for example. For this reason, the fixing element 24 must then be adapted depending on the configuration of the circumferential groove 42 or the stopper 34 in some cases.

  In order to assemble the rotor blade 10 in the blade carrier 16 by means of the fixing system 20 according to the invention, firstly the fixing body 22 is inserted into the axial groove 14 and already protrudes radially from the basic part 28. One end region 26 is inserted so as to be received by the circumferential groove 42. The first end region 26 then extends between the stopper 34 of the fixing element 32 and the corresponding part of the end face 40 of the wing carrier 16 with a little play. Subsequently, the rotor blade is inserted into the axial groove 14 of the blade carrier 16 from the pressure side 38 via the fixed body 22 with the blade foot 14. Finally, the second end region 26 ′ of the fixing body 22 is bent radially outward so that the wing foot 12 is axially fixed by both end regions 26, 26 ′. Yes.

The fixing system according to the invention is schematically shown by means of a perspective view, based on a part of a blade carrier having a moving blade fixed to the blade carrier, and in a sectional view along the bottom of the axial groove of the blade carrier. Fig. 2 schematically shows a fixing body of a fixing system according to the invention by means of perspective. Similarly, a fixation system according to the present invention is shown schematically in a view similar to FIG. The embodiment from FIG. 3 is shown schematically in another perspective view without a blade.

Explanation of symbols

A Direction of axial flow 10 Rotor blade 12 Wing foot 13 Wing foot end 14 Axial groove 15 Axial groove bottom 16 Blade carrier 20 Fixing system 22 Fixing body 24 Fixing element 26, 26 'End region 28 Base part 30 Weld seam 32 Independent fixed disk 34 Stopper 36 Screw 38 End face oriented upstream of the pressure-side blade carrier 38 'End face oriented upstream of the pressure-side blade foot 40 Downstream of the back-side blade carrier Oriented end face 40 'End face oriented downstream of the wing foot on the back side 42 Circumferential groove

Claims (10)

Each blade (10) is provided with a blade foot (12) which is inserted into an axial groove (14) of the blade carrier (16) so that the blade (10) has a radius. And a fixed body (22) is disposed between the wing foot (12) and the wing carrier (16) in the axial groove (14). Blades of an axial-flow turbomachine, each gripping the back side (40) of a blade carrier (16) oriented downstream by a first end region (26) of two end regions, respectively In the fixing system for (10),
A fixing element (24) integrally formed with the wing carrier (16) on the back side (40) of the wing carrier (16) oriented downstream is a first end region (26) of the fixing body (22). ) And an axial stopper (34) for preventing the spread of the first end region (26) for this fixed body, The axial stop (34) extends radially outward and supports the axial direction of the first end region (26) projecting radially outward. system.   In the assembled state, the first end region (26) of the stationary body (22) is arranged in a circumferential groove (42) between the stopper (34) and the blade carrier (16). The fixing system according to claim 1.   3. Fixing system according to claim 1 or 2, characterized in that the fixing element (24) is manufactured by turning and / or milling.   3. The fixing element (24) according to claim 1, wherein the fixing element (24) is manufactured as an independent fixing disk (32) or as an independent fixing ring and is connectable to an object integral with the wing carrier (16). Fixing system as described in.   The fixed body (22) protrudes axially beyond the axial groove (14) with both end regions (26, 26 ') and the end regions (26, 26') are incorporated. The fastening system according to any one of claims 1 to 4, characterized in that one end face (38, 40) of each wing carrier (16) is gripped from behind.   The end regions (26, 26 ') are wider than the base portion (28) connecting these end regions and wider than the axial groove (14), so that these end regions are axial grooves. 6. Fixing system according to claim 5, characterized in that it projects in the circumferential direction beyond (14).   In the assembled state, the end regions (26, 26 ') of the stationary body (22) protrude radially outward from the base portion (28), and these end regions are 7. Fixing system according to claim 5 or 6, characterized in that the end face (38 ', 40') of (12) and the part of the end face (38, 40) of the wing carrier (16) are gripped from behind. Each blade (10) is provided with a blade foot (12) which is inserted into an axial groove (14) of the blade carrier (16) so that the blade (10) has a radius. Fixed in the direction and circumferential direction, and a fixed body (22) is arranged between the wing foot (12) and the wing carrier (16) in the axial groove (14), and these fixed Dynamics of an axial-flow turbomachine in which the body grips from behind the back side (40) of a wing carrier (16) oriented downstream by a first end region (26) of two end regions, respectively. In the fixing disk (32) for axially fixing the wing (10),
A stationary disk (32) is located on the back side (40) of the wing carrier (16) oriented downstream for the first end region (26) of the stationary body (22) . An axial stopper (34) for preventing the end region (26) from spreading is formed, and the axial stopper (34) extends radially outward and radially outward. And a first end region (26) projecting in the axial direction, and fixed to the wing carrier (16).   The fixed disk according to claim 8, wherein the fixed disk is formed in a ring shape.   A fixed disk (32) is connectable to the wing carrier (16) on the first side and comprises a shoulder on this first side, and the wing carrier (16) and the fixed disk (32) are combined. In this case, a circumferential groove is formed between the fixed disk (32) and the blade carrier (16), and the first end region (26) of the fixed body (22) can be accommodated in the circumferential groove. The fixed disk according to claim 8, wherein the fixed disk is.

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