Turbomachine subassembly produced by additive manufacturing

Abstract

The invention relates to a subassembly (10) of a turbomachine having a main axis (A) and comprising: - a plurality of blades (12) distributed angularly about the main axis and each extending radially with respect to the main axis; - an internal radial member (14) connected to an internal radial end (12a) of each blade (12); - an external radial member (16) connected to an external radial end (12b) of each blade (12), characterized in that the cross-section of each blade (12), along an axial plane passing through the main axis (A), comprises a chevron portion (20) whose tip (22) is directed axially. The invention also relates to a method for producing the subassembly (10). Figure for the abstract: Figure 1

Description

Title of the invention: Turbomachine subassembly produced by additive manufacturing technical field

[0001] The invention relates to a turbomachine subassembly consisting of a plurality of blades connected to each other at their radial ends, to form a distributor or a straightener of the turbomachine.

[0002] The invention relates more particularly to a turbomachine sub-assembly produced according to an additive manufacturing process. PREVIOUS STATE OF THE ART

[0003] An additive manufacturing process makes it possible to produce a component of complex shapes in a single operation and requires little or no subsequent machining operation.

[0004] This manufacturing process consists of forming the component by melting successive layers of a constituent material of the component. This process can advantageously be a powder bed fusion process or a fused wire deposition process.

[0005] A turbomachine subassembly consists of a plurality of blades distributed around a main axis of the subassembly and two elements connecting the internal and external radial ends of the blades to each other.

[0006] Due to the structure of the subassembly, during the implementation of the manufacturing process, the main axis of the subassembly is oriented vertically according to the orientation of Earth's gravity. The primary purpose of this orientation is to limit any volumes of the subassembly that might be suspended on the powder bed, and thus limit the amount of material required to support these suspended volumes, which would then need to be melted and machined to remove this excess material.

[0007] The orientation of a blade with respect to this axis, that is to say its inclination with respect to the vertical, as well as the particular structure of the body of the blade (for example when it is hollow) do not allow the blade to maintain its shape throughout the entire process.

[0008] As a result, one or more supports are formed under each blade during the implementation of the manufacturing process, to support the blade.

[0009] Due to the presence of these supports on the sub-assembly, it is necessary to implement an additional machining step of the sub-assembly, which is intended to remove the supports.

[0010] This then increases the production time of the sub-assembly, as well as its cost because of the material used to form the supports.

[0011] The invention aims to provide a sub-assembly designed to limit the use of supports to support the portions of blades during formation. Description of the invention

[0012] The invention proposes a turbomachine subassembly having a main shaft and comprising

[0013] - a plurality of blades distributed angularly along the main axis and extending each radially with respect to the main axis;

[0014] - an internal radially connected element to an internal radial end of each pale ;

[0015] - an external radially connected member to an external radial end of each pale,

[0016] characterized in that the section of each blade, along an axial plane passing through the main axis, comprises a chevron portion whose tip is directed axially.

[0017] The chevron shape of the blades allows them to support themselves, thus eliminating the need for supports

[0018] Preferably, the section of each blade, along an axial plane passing through the main axis, comprises two radially aligned chevron portions, the tip of each chevron portion of which is directed axially.

[0019] Preferably, each chevron portion comprises two segments inclined relative to each other and relative to a direction parallel to the main axis which are joined at the tip.

[0020] Preferably, each segment is inclined with respect to the direction parallel to the main axis at an angle of approximately 45 degrees.

[0021] Preferably, the entire set of blades, the radially inner element and the radially outer element are made in a single monolithic element according to an additive manufacturing process.

[0022] Preferably, the subset constitutes an element of revolution centered on the principal axis (A).

[0023] Preferably, the subset constitutes a portion of an element of revolution centered on the principal axis, delimited by an angular sector.

[0024] The invention also proposes a method for producing, by additive manufacturing, a sub-assembly according to the invention, having a main axis and comprising:

[0025] - a plurality of blades distributed angularly along the main axis and extending each radially with respect to the main axis;

[0026] - an internal radially connected element to an internal radial end of each pale ;

[0027] - an external radially connected member to an external radial end of each pale,

[0028] in which the cross-section of each blade, along an axial plane passing through the main axis, comprises a chevron-shaped portion whose apex is directed axially,

[0029] characterized in that during the production of the subassembly, the main axis is parallel to a vertical direction, taken according to terrestrial gravity.

[0030] Preferably, the tip of the chevron portion is oriented vertically upwards. Brief description of the drawings

[0031] [Fig-1] is a schematic perspective representation of a subset of turbomachine comprising blades formed according to the invention

[0032] [Fig.2] is a cross-sectional view of the subassembly shown in [Fig.1], showing the profile of the blades and its arrangement during production. DETAILED DESCRIPTION OF THE INVENTION

[0033] A subset 10 of a turbomachine is shown in [Fig.1].

[0034] This subassembly 10 is for example a distributor of a turbine or a rectifier of a compressor.

[0035] The subassembly 10 has a main axis A and it comprises a plurality of blades 12 which are distributed regularly around the main axis A and which are oriented radially with respect to this main axis A, that is to say according to the same pitch of spacing between two adjacent blades.

[0036] According to an alternative embodiment not shown, the blades 12 are distributed irregularly around the main axis A, i.e. the blades are spaced at variable pitches.

[0037] The subassembly 10 comprises a radially internal member 14 which connects the internal radial ends 12a of the blades 12 together and a radially external member 16 which connects the external radial ends 12b of the blades 12 together.

[0038] Here, the subassembly 10 is an element of revolution centered on the principal axis A. Each of the radially internal member 14 and the radially external member 16 is thus of annular shape centered on the principal axis A.

[0039] According to an alternative embodiment not shown, the subassembly 10 consists of a portion of the rectifier or distributor and extends over only an angular sector. Each of the radially inner element 14 and the radially outer element 16 is then in the form of a sector of a ring centered on the principal axis A and delimited by the angular sector delimiting the subassembly.

[0040] A distributor or a turbomachine rectifier can thus be formed in its entirety in a single subassembly 10 when it consists of an element of revolution or it can be formed by the assembly of several subassemblies 10 when these form angular sectors.

[0041] Each blade 12 has a main radial orientation with respect to the main axis A.

[0042] It comprises an internal radial end 12a called the foot end by which the blade 12 is connected to the radially internal member 14 and an external radial end 12b called the head end by which the blade 12 is connected to the radially external member 16.

[0043] Subassembly 10 is produced using a process known as additive manufacturing.

[0044] This process consists of progressively producing the sub-assembly 10 layer by layer, by melting a quantity of material constituting the sub-assembly 10, for example by using a laser.

[0045] Due to the particular shape of the subassembly 10, and as can be seen in [Fig.2], it is produced with its main axis A oriented vertically, according to terrestrial gravity, and the layers of material are stacked vertically one on top of the other and on a base plate 18.

[0046] During the implementation of the production process of subassembly 10, the radially inner member 14, the radially outer member 16 and the blades are formed progressively and simultaneously, so as to obtain a one-piece component, i.e. monolithic.

[0047] To limit the overhang length of each blade 12, that is to say the length of the blade 12 which extends at a distance from the radially inner member 14 or the radially outer member 16, each blade 12 has a chevron portion 20 whose tip 22 is directed along the main axis A.

[0048] As can be seen in more detail in [Fig.2], the chevron portion 20 consists of two segments 24 inclined relative to each other and relative to an axial direction parallel to the main axis A.

[0049] According to a preferred embodiment, the angle of inclination 26 between each segment 24 and the principal axis A is approximately 45 degrees. It will be understood that the invention is not limited to this embodiment and that the value of the angle of inclination 26 may be greater or less than this value of 45 degrees. By way of non-limiting example, the angle of inclination 26 between each segment 24 and the principal axis A is between 30 and 65°.

[0050] According to the embodiment shown in the figures, the blade 12 comprises a single chevron portion 20 and this chevron portion 20 extends over the entire radial length of the blade 12.

[0051] According to an alternative embodiment not shown, the blade 12 comprises two adjacent chevron portions 20, giving the blade 12 an M shape in which the points 22 of the two chevrons are oriented axially in the same direction.

[0052] According to this variant, only one support (not shown) is required during production for the part corresponding to the connection between the two chevron portions 20.

[0053] The dimensions of such a support are limited compared to a prior art support because it only serves to support the contiguous parts of the two adjacent chevron portions 20.

[0054] As previously stated, the production process of the subassembly consists of superimposing layers of the material constituting the subassembly 10. Also, the main axis A of the subassembly 10 is oriented parallel to the vertical.

[0055] Also, each blade is chevron-shaped with the point 22 of this chevron oriented axially. Preferably, the point 22 of the chevron portion is oriented vertically upwards.

[0056] Thus, during the implementation of the production process of subassembly 10, each blade 12 is produced starting from its radial ends 12a, 12b, at which point the blade 12 is connected to the radially inner member 14 and to the radially outer member 16.

[0057] Thus, the segments 24 of the chevron portion 20 support themselves during the implementation of the process and are progressively formed until they meet at the point 22 of the chevron portion 20.

[0058] This makes it possible to avoid using a support to keep the segments 24 of the blade 12 in shape, thus limiting the amount of material lost.

[0059] In the case of a blade 12 formed from two or more chevron portions 20, as previously stated, a support is used for the portion

Claims

Demands

1. A method for producing by additive manufacturing a subassembly (10) of a turbomachine having a main axis (A) and comprising - a plurality of blades (12) distributed angularly along the main axis and each extending radially with respect to the main axis, the cross-section of each blade (12), along an axial plane passing through the main axis (A) comprises a chevron portion (20) whose tip (22) is directed axially; - a radially internal member (14) connected to an internal radial end (12a) of each blade (12); - a radially external member (16) connected to an external radial end (12b) of each blade (12), in which, during the production of the subassembly (10), the main axis (A) is parallel to a vertical direction, taken according to terrestrial gravity, characterized in that during the production of the subassembly (10), the tip (22) of the chevron portion (20) is oriented vertically upwards.

2. Subassembly (10) obtained by a process according to the preceding claim, characterized in that the section of each blade (12), along an axial plane passing through the main axis, comprises two radially aligned chevron portions (20) of which the tip (22) of each chevron portion (20) is directed axially.

3. Subassembly (10) according to the preceding claim, characterized in that each chevron portion (20) comprises two segments inclined to each other and to a direction parallel to the main axis (A) which are joined at the tip (22).

4. Subassembly (10) according to the preceding claim, characterized in that each segment (24) is inclined with respect to the direction parallel to the main axis at an angle of inclination (26) of approximately 45 degrees.

5. Subassembly (10) according to any one of claims 2 to 4, characterized in that the set of blades (12), the radially inner member (14) and the radially outer member (16) are made in a single monolithic element according to an additive manufacturing process.

6. Subassembly (10) according to any one of claims 2 to 5, characterized in that it constitutes an element of revolution centered on the principal axis (A).

7. Subassembly (10) according to any one of claims 2 to 5, characterized in that it constitutes a portion of an element of revolution centered on the principal axis (A), delimited by an angular sector.

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