Turbomachine rotor blade

Abstract

A turbomachine rotor blade, said blade having, at the distal end thereof, a heel comprising: a platform (2) having a first edge (201) on the lower side and a second edge (202) on the upper side, at least one sealing member having a first end portion (301) on the lower side and a second end portion (302) on the upper side, said sealing member having a sealing top that extends radially outwards from said platform (2) between said first and second end portions (301, 302), characterized in that, for at least one sealing member, the heel (105) comprises, on at least at one of the edges (201, 202), a portion forming a bowl (5) extending along the end portion (301, 302) of the sealing member which corresponds to the edge (201, 202), the portion forming the bowl (5) being suitable for receiving a deposit of anti-wear material.

Claims

1. A rotor blade for a turbomachine, said blade having at its distal end (103) a heel (105) including: a platform (2) having a first edge (201) on the lower side and a second edge (202) on the upper side, at least one seal lip (3) having a first end portion (301) on the lower side and a second end portion (302) on the upper side, said seal lip (3) having a seal lip top extending radially outward from said platform (2) between said first and second end portions (301, 302), wherein, for at least one seal lip (3) the heel (105) includes at one of the edges (201, 202) at least one portion forming a cup (5) extending along the end portion (301, 302) of the seal lip (3) which corresponds to the edge (201, 202), the portion forming a cup (5) designed to receive a deposit of an anti-wear material (7), and in that the at least one portion includes a layer of antiwear material (7) deposited by loading a melted alloy into each cup (5) thus formed, wherein each portion forming a cup (5) includes two lateral walls (501, 502) extending on either side of the end portion (301, 302) of the corresponding seal lip (3), which lateral walls extending on either side of the seal lip form lateral walls of the cup and the end portion (301, 302) of the seal lip (3) forms the bottom of the cup (5).

2. The rotor blade according to claim 1, wherein the heel (105) includes, for at least one seal lip (3), at the first (201) respectively second (202) edge, a first, respectively second portion forming a cup (5) extending along the first, respectively second, end portion (301, 302) of the seal lip (3), the first, respectively second portion forming a cup (5) being designed to receive a deposit of anti-wear material (7).

3. The rotor blade according to claim 1, including an upstream seal lip (3) and a downstream seal lip (4).

4. The rotor blade according to claim 1, wherein the anti-wear material is a cobalt-based metal alloy.

5. The rotor blade of a turbomachine according to claim 1, wherein the blade is a rough blade part prior to machining.

6. The rotor blade of a turbomachine according to claim 1, wherein the blade is a machined blade.

7. The rotor blade according to claim 1, wherein the anti-wear material extends on the whole height of the seal lip.

8. A method for depositing anti-wear material on a rotor blade of a turbomachine, comprising: supplying a rough part of a rotor blade of a turbomachine prior to machining, said part having at its distal end (103) a heel (105) including: a platform (2) having a first edge (201) on the lower side and a second edge (202) on the upper side, at least one seal lip (3) having a first end portion (301) on the lower side and a second end portion (302) on the upper side, said seal lip (3) having a seal lip top extending radially outward from said platform (2) between said first and second end portions (301, 302), such that, for at least one seal lip (3), the heel (105) includes at one of the edges (201, 202) at least one portion forming a cup (5) extending along the end portion (301, 302) of the seal lip (3) which corresponds to the edge (201, 202), the portion forming a cup (5) being designed to receive a deposit of anti-wear material (7), wherein each portion forming a cup (5) includes two lateral walls (501, 502) extending on either side of the end portion (301, 302) of the corresponding seal lip (3), which lateral walls extending on either side of the seal lip form lateral walls of the cup and the end portion (301, 302) of the seal lip (3) forms the bottom of the cup (5), depositing a layer of anti-wear material (7) by loading with a melted alloy into each cup (5) formed, and machining lateral walls (501, 502) of the cup (5) extending past the layer of anti-wear material (7) deposited.

9. The method according to claim 8, further comprising after said machining, sanding the surface of the layer of anti-wear material (7) and the lateral walls.

Description

BRIEF DESCRIPTION OF FIGURES

(1) Other features and advantages of the invention will be revealed in the description hereafter of one embodiment. In the appended drawings:

(2) FIG. 1 shows a detail of a rotor blade of a turbomachine according to the prior art,

(3) FIG. 2 shows a rotor blade of a turbomachine according to an example of an embodiment of the invention,

(4) FIG. 3a shows a seal lip of the blade of FIG. 2 without the deposit of anti-wear material,

(5) FIG. 3b shows the seal lip of FIG. 3a with the deposit of anti-wear material,

(6) FIG. 4a shows a view along a radial axis of the heel of a rough rotor blade part according to an example of an embodiment of the invention,

(7) FIG. 4b shows a view along a radial axis of the heel of a rotor blade of a turbomachine after application to the rough part of FIG. 5a of a method according to an example of an embodiment of the invention,

(8) FIG. 5a shows a perspective view of the heel of FIG. 4a,

(9) FIG. 5b shows a perspective view of the heel of FIG. 5a after deposit of the anti-wear material.

(10) FIG. 5c shows a perspective view of the heel of FIG. 5b after machining and sanding,

(11) FIG. 6 shows in the form of a diagram of the method according to one example of an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

(12) Example of a Blade

(13) General Structure of the Blade

(14) Referring to FIGS. 2 to 5c, an example of a rotor blade of a turbomachine. Such a blade can for example be a blade of an airplane turbojet, for example at a low-pressure stage.

(15) The blade includes a lower side and an upper side positioned on either side of a stacking axis. The blade can thus include an airfoil 101 extending along a stacking axis of the blade. The airfoil 101 extends between a proximal end 102 and a distal end 103 of the blade.

(16) The blade includes a root 104 at its proximal end 102, by which it is for example attached to a disc of the rotor of the turbomachine. The disc can drive the blade in rotation about an axis of the turbomachine.

(17) Heel

(18) The blade has at its distal end 103 a heel 105. The heel 105 can be made in such a manner that, when several movable blades are attached to a rotor disc, their heels 105 are set edge to edge so as to form a rotating ring delimiting a surface of revolution about an axis of rotation of the blades. This ring has in particular the function of delimiting an outer surface of a passage for the gas flow circulating between the airfoils 101 and thus to limit possible gas leaks at the distal end 103 of the blades.

(19) The heel 105 includes a platform 2 having a first edge 201 on the lower side and a second edge 202 on the upper side. The first and second edges 201 and 202 are for example opposite lateral edges. The platform 2 can delimit on the outside the gas flow passage circulating between the blades 101.

(20) Seal Lip

(21) The heel 105 includes at least one seal lip 3. The seal lip 3 has a first end portion 301 on the lower side and a second end portion 302 on the upper side. The seal lip 3 has a seal lip top extending radially outward from said platform 2 between said first 301 and second 302 end portions. The heel 105 can include an upstream seal lip 3 and a downstream seal lip 4, upstream and downstream being defined according to the direction of gas flow. The upstream 3 and downstream 4 seal lips can be made in such a manner that, when several movable blades are attached to a rotor disc, the seal lips 3 and 4 of the blades are set edge to edge so as to form a rotating ring along the axis of rotation of the blades, this ring being contained substantially within a radial plane. Such a ring makes it possible to limit the existing clearance between the blades and a stator, or a stator shroud, which surrounds them, so as to limit possible gas leaks at this location.

(22) The part of the platform 2 extending upstream of the upstream seal lip 3 constitutes an upstream portion 203 or upstream spoiler. The portion of the platform 2 extending downstream of the downstream seal lip 4 constitutes a downstream portion 205 or downstream spoiler. Between the upstream portion 203 and the downstream portion 205, the platform 2 has a central part 204 extending between the upstream 3 and downstream 4 seal lips.

(23) For the purpose of damping vibrations to which the blades are subjected in operation, the blades can be mounted on their rotor disc with a torsional stress about their stacking axis. Thus, the platforms 2 can be dimensioned in such a manner that each blade is given a torsional stress by pressing against its neighbors at the heels 105, mainly along the end portions of the seal lips 3 and 4.

(24) Portion Forming a Cup

(25) For at least one seal lip 3, for example for each seal lip 3, the heel 105 includes, at one of its edges 201 and 202 at least, a portion forming a cup 5 extending along the end portions 301 or 302 of the seal lip 3 which corresponds to the edge 201 or 202, the portion forming the cup 5 being designed to receive a deposit of anti-wear material 7. Thus, the heel 105 can include, for at least one seal lip 3, for example for all seal lips 3, at the first 201, respectively second 202 edge, a first, respectively second portion forming a cup 5 extending along the first 301, respectively second 302 end portion of the seal lip 3, the first, respectively second portion forming a cup 5 being designed to receive a deposit of an anti-wear material 7. Compared to the prior art, the portion forming the cup 5, along an end portion 301 or 302 of the seal lip 3, allows stiffening of this seal lip 3 and therefore to better withstand the loads caused by contact with adjacent heels 105. The referred figures represent portions forming a cup 5 at the upstream seal lip 3, but such portions forming cups 5 can be present, alternatively or complementarily, at the downstream seal lip 4.

(26) Each portion forming a cup 5 can include two walls 501 and 502 extending on either side of the end portion of the corresponding seal lip 3. These walls thus form two faces 501 and 502 forming lateral walls of the cup 5 and the end portion of the seal lip 3 forms the bottom of the cup 5. These walls 501 and 502 can be reworked during subsequent machining.

(27) Deposit of Anti-Wear Material

(28) Thus the blade can include a layer of anti-wear material 7 deposited in each cup 5 thus formed. The [material] constituting the blade generally has poor resistance to wear and the anti-wear material makes it possible to extend its lifetime by protecting the parts subjected to wear.

(29) The layer of anti-wear material 7 can be obtained by brazing plates of a specific alloy with high hardness to the cups 5.

(30) The layer of anti-wear material 7 can be obtained by loading this lateral face with a melted alloy. The necessary heat can for example come from an electric arc sheathed with neutral gas or even from a laser beam. The anti-wear material 7 can be a cobalt-based alloy, for example an alloy of cobalt, chromium tungsten and carbon, for example such an alloy of the type of those marketed under the brand name Stellite, having good anti-wear properties. The anti-wear material 7 can also be made on a rough blade from the foundry prior to machining, by Stelliting. The presence of the cup 5 in the seal lip 3 makes it possible to deposit a small quantity and without any risk of overflowing. Indeed, the portion forming the cup 5 acts like a gutter during deposit of the melted material, overflow being limited by the edges of the cup 5. The edges of the walls of the cup 5 extending past the anti-wear material deposited can then be removed during subsequent machining allowing the machined blade of being obtained.

(31) The walls 501 and 502 of the cup portion 5 must thus have sufficient thickness to not melt completely during depositing of the melted anti-wear material. Their condition after depositing can however be modified during machining. Thus a thickness of 1.5 mm for the walls 501 and 502, for example, is sufficient. Likewise, the deposit of anti-wear material 7 does not need to have imperfections because the form of the layer can be modified during subsequent machining and possible subsequent sanding.

(32) Such a blade also allows depositing of Stellite along the seal lip 3, which provides a greater lifetime for the blade because the areas protected by the anti-wear material 7 are supported on the seal lip 3. Moreover, such a blade allows automated depositing of anti-wear material and no longer requires any manual operation. As the material distributes itself along the cup 5, it is thus easier to accomplish a deposit of a small quantity of material. It is thus possible to obtain, after machining, a layer of anti-wear material 7. The layer of anti-wear material 7 has for example a thickness of 1 mm or a greater thickness.

(33) Moreover, such a blade does not require a subsequent checking stage, the portion forming a cup 5 avoiding any overflow and the final form of the portion being obtained after machining. The result is a simplification of the method for depositing the anti-wear material, and more generally of the method of manufacture of rotor blades for a turbomachine.

(34) Example Method

(35) Referring to FIG. 6, a method for depositing anti-wear material on a rotor blade of a turbomachine is described there. The method includes a first step 601 consisting of supplying a rough rotor blade for a turbomachine as describe above and as shown in FIG. 5a. The method includes a second step consisting of depositing a layer of anti-wear material 7 as described above in each cup 5 formed, to obtain a heel 105 as shown in FIG. 5b. The method includes a third step 603 consisting of machining the edges of the walls 501 and 502 of the cup 5 extending past the layer of anti-wear material 7 deposited, so as to obtain a machined blade as shown in FIG. 5c.

(36) The method can include a fourth step 604 consisting of sanding the surface of the layer of the anti-wear material 7 and of the portion forming a cup 5 after machining, so as to make them smooth.