阅读说明：本技术 用于涡轮机组件的尺寸检查的方法 (Method for dimensional inspection of a turbomachine component ) 是由 罗杰·乔治·卡曾 阿诺德·亚历山大·文森特 于 2020-04-23 设计创作，主要内容包括：本发明涉及一种待检查的涡轮机组件的尺寸检查方法,该涡轮机组件包括：由第二周边表面(11)限定的第一表面(10),第二周边表面大致横向于所述第一表面；以及由具有对应于所述第一表面(10)的理论表面(10T)的数值理论模型定义的轮廓,所述第一表面(10)具有比所述第二周边表面(11)更大的尺寸,所述方法包括以下步骤：-在所述数值理论模型的所述理论表面(10T)上确定理论点(Pt；Pt1)；-在所述待检查组件(1)的所述第一表面(10)上校正校准点(Pe；Pe1)；-计算每个理论点(Pt；P1)相对于对应的校准点(Pe；Pe1)的偏移轴线(AD)；-根据所述偏移轴线在所述待检查组件的所述第二周边表面上获取待检查的点(Pc,Pc1,Pc2)。(The invention relates to a method for checking the dimensions of a turbomachine component to be checked, comprising: a first surface (10) defined by a second peripheral surface (11) substantially transverse to said first surface; and a profile defined by a numerical theoretical model having a theoretical surface (10T) corresponding to said first surface (10), said first surface (10) having a larger size than said second peripheral surface (11), said method comprising the steps of: -determining theoretical points (Pt; Pt1) on said theoretical surface (10T) of said numerical theoretical model; -correcting calibration points (Pe; Pe1) on said first surface (10) of said assembly to be inspected (1); -calculating an offset Axis (AD) of each theoretical point (Pt; P1) with respect to the corresponding calibration point (Pe; Pe 1); -acquiring a point to be inspected (Pc, Pc1, Pc2) on the second peripheral surface of the component to be inspected according to the offset axis.)

1. A method of dimensional control of a turbine component to be controlled, the turbine component to be controlled comprising: a first surface (10) defined by a second peripheral surface (11) transversal to said first surface; and a profile defined by a numerical theoretical model having a theoretical surface (10T) corresponding to said first surface (10), said first surface (10) having a larger size than said second peripheral surface (11), said method comprising the steps of:

-determining theoretical points (Pt; Pt1) on said theoretical surface (10T) of said numerical theoretical model;

-correcting a calibration point (Pe; Pe1) on the first surface (10) of the component (1) to be controlled;

-calculating an offset Axis (AD) of each theoretical point (Pt; P1) with respect to the corresponding calibration point (Pe; Pe1),

-taking a control point (Pc, Pc1, Pc2) on the second peripheral surface of the component to be controlled according to the offset axis.

2. A method of dimensional control according to claim 1, wherein the theoretical points are defined in terms of the surface and/or geometry of the first surface.

3. The dimensional control method according to claim 1, characterized in that the theoretical points are arranged adjacent to the periphery of the theoretical surface (10T) of the theoretical model.

4. A dimensional control method according to any of the preceding claims, wherein the step of calculating the offset axis comprises: and comparing the spatial data of each theoretical point of the theoretical model with the spatial data of each corresponding calibration point.

5. Dimensional control method according to the preceding claim, characterized in that said step of comparing comprises the steps of:

-drawing a straight line (D) between at least one theoretical point (Pt1) and a corresponding calibration point (Pe 1);

-measuring a spatial offset between the theoretical point and the corresponding calibration point;

-calculating a displacement axis of a machining tool of a machining surface of the component to be controlled;

-determining the direction cosine of the offset axis from a theoretical normal of a theoretical surface (10T) of the theoretical component at the theoretical point (Pt), the straight line (D) and the displacement axis of the machining tool.

6. The dimensional control method according to any one of the preceding claims, wherein the obtaining step comprises: a step of calculating the spatial coordinates of the point to be controlled on the component to be controlled by applying the offset axis to the theoretical coordinates of the point to be controlled.

7. The dimensional control method according to any one of the preceding claims, characterized in that it comprises positioning a palpation element (31) opposite said first surface of the component to be controlled, the axis of said palpation element (31) being orthogonal to said first surface, to perform said correction step.

8. A dimensional control method according to any of the preceding claims, characterized in that the correction step and the acquisition step are performed by a control device of the coordinate measuring machine type.

9. The sizing method according to any of the preceding claims, wherein 2 to 8 theoretical points are performed in the obtaining step.

10. A dimensional control method according to any of the preceding claims, wherein the turbine component is a turbine movable blade (1) comprising a blade (2) and a shroud (6) provided at a radially outer end of the blade, the shroud (6) comprising a radially inner surface (10) defined by a radially peripheral surface (11), the first surface being the radially inner surface, and the second peripheral surface being the radially peripheral surface.

11. A dimensional control method according to any of claims 8 to 10, wherein the coordinate measuring machine comprises the palpation element.

12. The dimensional control method according to any of the preceding claims, wherein during the acquiring step, an axis of the palpation element is orthogonal to the second perimeter surface.

Technical Field

The present invention relates to the manufacture of turbine components, and more particularly, to a method of dimensional control of turbine components (e.g., turbine blades manufactured by casting or forging).

Background

Increasing the performance of a turbine requires the production of mechanical components, such as blades, with an optimized aerodynamic profile. A twin-body turbine comprises, for example, a ring of blades for a low-pressure turbine stage with dimensions (thickness or width) of a few millimeters. These blade rings are typically manufactured by casting and pouring metal into a mold using a technique known as lost wax, which allows the desired blade shape to be obtained directly without the need to perform machining steps to obtain the finished assembly.

However, casting techniques do not always allow for the required degree of refinement of a particular portion of the blade ring, and therefore additional machining is necessary to provide an aerodynamically optimized assembly. The machining requires a very specific parameterization, which is defined empirically on the basis of theoretical components and very precise contour data of the components to be obtained.

These components are dimensionally controlled to check whether it is necessary to machine them during machining, even after machining, and to verify their conformity after machining. Due to the tolerances allowed for the cast components, the very small dimensions of these components and possible deformations, the control times are long and cumbersome. Such controls typically operate using a Coordinate Measuring Machine (CMM). The coordinate measuring machine uses the palpation element and data from the theoretical assembly to palpate or measure in a contact or non-contact manner. Examples of control are described in documents FR-A1-2989610, CN-B-104316016 and JP-A-S60159601.

This control has proven to be more complex for the blade shroud of a turbine. In fact, the shroud at the radially outer end of the blades has a complex shape with a relatively small measurement area and rounded edges. However, for a particular component, the reference point is determined from where control of the component should begin, and is located on the shroud. For example, if the assembly has tolerance problems as described above, there is a large offset between the reference point of the theoretical assembly and the reference point of the assembly to be controlled, so that the palpation sensor will start measuring at the wrong position. This may result in a lack of accuracy in controlling the components. To address this problem, the operator may have to change the machine settings or manually move the assembly or palpation element until the correct reference point is found on the assembly to be controlled.

One of the applicant's objectives is in particular to provide a faster, automatic and inexpensive dimensional control method of a turbomachine assembly.

Disclosure of Invention

The present application achieves this object by a method for dimensional control of a turbomachine component to be controlled, the turbomachine component comprising: a first surface defined by a second peripheral surface, the second peripheral surface being transverse to the first surface; and a contour defined by a numerical theoretical model having a theoretical surface corresponding to the first surface, the first surface having a larger dimension than the second peripheral surface, the method comprising the steps of:

-determining theoretical points on said theoretical surface of said numerical theoretical model;

-correcting calibration points on said first surface of said component to be controlled;

-calculating an axis of offset of each theoretical point with respect to the corresponding calibration point,

-acquiring control points on said second peripheral surface of said component to be controlled according to said offset axis.

This solution may thus allow the above-mentioned objects to be achieved. In particular, the method allows checking the compliance of the assembly and the point to be controlled can be determined more quickly, although in this case the shroud of the blade is not at the theoretical starting position foreseen in the theoretical model. In other words, this method may allow the start of palpation at the correct location of the surface to be inspected, even if the shield is not in the correct location. The control method is also easily implemented by a first surface having a larger size than a second surface, which is typically very narrow. The steps of determining, calibrating, and calculating the offset axis can be accomplished in less than ten seconds, which is very fast.

The dimensional control method further includes one or more of the following characteristics, used alone or in combination:

-said theoretical points are defined according to the surface and/or geometry of said first surface.

-the theoretical points are arranged adjacent to the perimeter of a theoretical surface of the theoretical model.

-said step of calculating said offset axis comprises: and comparing the spatial data of each theoretical point of the theoretical model with the spatial data of each corresponding calibration point.

-the step of comparing comprises the steps of:

o-drawing a straight line between at least one theoretical point and the corresponding calibration point;

o-measuring the spatial offset between the theoretical point and the calibration point;

o-calculating a displacement axis of a machining tool of a machining surface of the component to be controlled;

o-determining the directional cosine of the offset axis from a theoretical normal of a theoretical surface of the theoretical component at the theoretical point, the straight line and the displacement axis of the machining tool.

-the step of obtaining comprises: a step of calculating the spatial coordinates of the point to be checked on the assembly by applying the offset axis to the theoretical coordinates of the theoretical point to be controlled.

-the method comprises positioning a palpation element opposite said first surface of said component to be controlled, the axis of said palpation element being orthogonal to said first surface, to perform said correction step.

-said calibration step and said acquisition step are performed by a control device of the coordinate measuring machine type.

-defining 2 to 8 theoretical points in said determining step.

-the turbine assembly is a turbine movable blade comprising a blade and a shroud disposed at a radially outer end of the blade, the shroud comprising a radially inner surface defined by a radially peripheral surface, the first surface being the radially inner surface of the shroud, and the second surface being the radially peripheral surface of the shroud.

-the coordinate measuring machine comprises the palpation element.

-during the acquiring step, the axis of the palpation element is orthogonal to the second perimeter surface.

Drawings

Further features and advantages of the present invention will become apparent from the following detailed description, to which reference is made for an understanding of the accompanying drawings, in which:

fig. 1 schematically shows a turbine blade to be controlled for which there is a difference in position between the shroud of the theoretical assembly and the shroud of the blade to be controlled.

FIG. 2 is a schematic top view of an exemplary turbine bucket shroud surface to be controlled.

FIG. 3 is a schematic illustration of an exemplary spatial offset between a theoretical plane and an actual plane, an

Fig. 4 shows schematically different positions of a control device according to the invention, such as a coordinate measuring machine.

Detailed Description

Fig. 1 shows a turbomachine component obtained with a lost-wax casting operation and to be controlled to check whether its dimensions correspond to theoretical components or models obtained by computer aided design or mapping (CAO/DAO) using software provided for this purpose.

In particular, the turbine assembly is a movable blade 1 of a low-pressure turbine. Of course, the blade may be a distributor blade, or alternatively, a blade for equipping another component of the turbine.

Turbines (not shown), particularly dual flow turbines having a longitudinal axis, typically include a gas generator with a fan mounted upstream. In general terms, in the present invention, the terms "upstream" and "downstream" are defined with respect to the fluid flow in the turbomachine, here along the longitudinal axis X. The gas generator includes a gas compressor assembly (which may include a low pressure compressor and a high pressure compressor), a combustor, and a turbine assembly (which may include a high pressure turbine and a low pressure turbine). The gas generator is crossed by a primary aerodynamic flow circulating in the secondary duct and generated by a fan. A secondary aerodynamic flow is also generated by the fan and circulates around the gas generator in a secondary duct, coaxial to the main duct.

Each turbomachine includes one or more stages arranged in succession along the longitudinal axis of the turbomachine. Each turbine stage includes a blade movable sheave forming a rotor and a blade fixed sheave forming a stator. The blades of the stator are referred to as distributor blades.

Each movable sheave comprises an annular disc centered on the longitudinal axis and a plurality of movable vanes mounted on the periphery of the disc. The vanes are distributed circumferentially and evenly around the movable wheel. Each movable wheel is arranged downstream of the fixed wheel of the distributor blade.

Referring to fig. 1, a movable blade 1 comprises a root (not shown) and a blade 2 extending from the root along a radial axis Z (which is perpendicular to the longitudinal axis when the blade is mounted in a turbine). The root is intended to fit into a correspondingly shaped groove of a disc, for which purpose the disc comprises a plurality of grooves evenly distributed around its circumference.

The fan blade 2 comprises a leading edge 3 and a trailing edge 4, in this example opposite along the longitudinal axis X. Each fan blade 2 is arranged in the aerodynamic flow such that the leading edge 3 is upstream of the trailing edge 4. The leading edge 3 and the trailing edge 4 are connected by intrados and extrados 5 opposite along the transverse axis. The transverse axis T is perpendicular to the longitudinal axis X and the radial axis Z.

The movable blade 1 further comprises a shroud 6 extending from the blade 2. The shroud 6 is located at the radially outer end of the fan blade 2 and transverse thereto. Specifically, the shroud 6 is disposed opposite to the root of the blade in the radial direction. The shield 6 generally comprises a platform 7 for forming a radially outer wall portion of the main duct. The shroud 6 is provided with wipers (wiper)8 which extend radially from a radially outer surface 9 of the platform 7. The radially inner surface 10 is opposite the radially outer surface 9 and is oriented substantially towards the root of the blade. The radially inner surface 10 is defined by a radially peripheral surface 11 connecting the radially inner surface 10 and the radially outer surface 9.

The radially inner surface is defined in a first plane XT (defined by the longitudinal axis and the transverse axis) perpendicular to the radial axis. The radially inner surface is flat or substantially flat. The radially inner surface has a larger dimension than the peripheral surface 11. As shown in particular in fig. 1, the peripheral surface 11 has a height h along the radial axis which is very small or narrow compared to the width l of the radially inner surface 10.

As shown in fig. 4, the platform 7 also extends along the longitudinal axis X. The shroud 6 comprises a first edge 12 and a second edge 13 opposite each other along the transverse axis T, each for making circumferential contact with the shroud of an adjacent blade. This makes it possible to prevent displacement of the vanes in the axial and circumferential directions. Further, the platform comprises an upstream side 14 and a downstream side 15 along the longitudinal axis and opposite to each other. The upstream and downstream sides 14, 15 and the first and second edges 12, 13 define a radially peripheral surface 11.

The dimensional control is performed by a control device 30, which may be of the Coordinate Measuring Machine (CMM) type. The control device 30 comprises a palpation element 31, which in this example is used for the measurement point without touching the surface of the blade, in particular the surface of the shroud. Typically, the control device 30 also includes an electronic control system or microcontroller having a computing device and memory.

Fig. 1 also shows, in dashed lines, the position of the shroud 6T corresponding to the theoretical definition of the shroud of the theoretical blade designed in the theoretical model of the design software. It can be seen that the shroud 6T of the theoretical blade and the shroud 6 of the blade to be controlled are offset in position along the radial axis. The theoretical shroud includes a theoretical radially inner surface 10T and a theoretical peripheral surface 11T transverse to the theoretical radially inner surface. The theoretical radially inner surface corresponds to the radially inner surface 10 and the theoretical peripheral surface corresponds to the radially peripheral surface 11.

Although there may be an offset in the position of the theoretical shroud relative to the shroud of the actual component to be controlled or measured, it is desirable to control the turbine blades as quickly as possible in order to know whether it is conforming or should be indicated as a rejected component.

To this end, the present application applies a method of dimensional control of the component to be controlled, in this case a movable blade, as described below. The method advantageously comprises the step of positioning the blade to be controlled on a support 32 equipped with control means 30. Specifically, the component to be controlled is positioned on the stent 32 such that its frame of reference coincides with the stent frame of reference 32. The blade reference frame consists of a longitudinal axis, a radial axis, and a transverse axis.

The radially inner surface 10 of the platform is oriented in space. In this example, referring to fig. 4, a first plane XT of the radially inner surface 10 is parallel to the vertical direction.

The determination step of the theoretical point Pt is carried out on the theoretical surface 10T of the theoretical shroud 6T of the theoretical assembly (see fig. 2). These theoretical points are designed by calculations in a theoretical model, for example, simultaneously with the design of said theoretical model of the blade to be manufactured (to be controlled). These theoretical points are also defined according to the geometry of the surface or shroud to be measured. These theoretical points correspond to reference points for starting the respective points to be controlled in the control theory assembly. In this example, at least two theoretical points are determined. In the example shown in fig. 2, four theoretical points are determined.

The correction of the calibration point Pe or reference point is made on the surface of the shroud, in this example on the surface of the radially inner surface 10 of the blade to be controlled (see fig. 4). In this example, at least two calibration points are determined. This step is performed by the palpation element 31 being moved to face the radially inner surface. Specifically, during the calibration step, the axis of the palpation element 31 is orthogonal to the radially inner surface of the shield. This allows the position of the component to be determined. Moreover, the displacement of the palpation element is substantially perpendicular to the surface to be corrected. It should be noted that the surface is not perfectly planar. These calibration points on the component to be controlled must correspond to theoretical points on the component to be controlled. In this example, four calibration points are corrected.

Referring to fig. 2, the theoretical points (and calibration points) are disposed at the locations where the thickness or height of the shroud is lowest. In this example, the theoretical points are arranged adjacent or as close as possible to the perimeter P of the theoretical surface 10T of the theoretical component. This is to be adjacent to the point on the shroud to be subsequently controlled and to allow control of the compliance of the components to be controlled. These points to be controlled are defined in a theoretical model of the CAO/DAO software.

According to the method, a calculation of the offset axis of at least one theoretical point with respect to the corresponding calibration point is then carried out. In this step, the spatial or three-dimensional data of the theoretical points of the theoretical model are compared with the corresponding calibration points on the component to be controlled. This comparison is advantageously performed in an electronic control system. Advantageously, all theoretical points are compared with corresponding calibration points. This makes it possible to check whether the calibration points are in the correct position and correspond to the spatial coordinates of the theoretical points.

To this end, as schematically shown in fig. 3, a straight line D (in the electronic control system) is drawn between the theoretical point Pt1 and the calibration point Pe 1. It is checked whether there is a spatial offset between the theoretical point and the corresponding calibration point. According to fig. 3, the calibration points do not correspond to the theoretical points in terms of position and spatial coordinates, and the spatial offset needs to be determined.

The system determines the axis of displacement of the machining tool (after the assembly has been molded) on the work surface of the assembly to be controlled. Due to the predefined machining parameters, the displacement axis of the tool can be obtained. The directional cosines of the vectors of the offset axes (csx, csy, csz in the theoretical component reference frame) are derived. Advantageously, the direction cosine is constant.

The direction cosine of the offset axis is determined from the theoretical normal of the theoretical surface of the theoretical component (corresponding to the radially inner surface) at the theoretical point Pt, the straight line D and the displacement axis of the machining tool.

Once the offset axis has been determined, the system calculates or recalculates the three-dimensional coordinates of the point Pc to be controlled by applying this offset axis AD.

In fig. 4, the step of obtaining the respective points Pc1, Pc2 at the radially peripheral surface 11 of the shroud 6 of the assembly to be controlled can be seen. This step allows to control the assembly, in particular to enable the dimensions of the shield 6 to be conformed to the required tolerances.

This method describes the use of the radially inner surface of the shroud as a reference surface to control the peripheral surface. Of course, the reference surface may be a radially outer surface and the surface to be controlled is a peripheral surface transverse to and adjacent to the radially inner surface.