Design method of self-positioning blade chord length gauge

Abstract

The application provides a self-positioning blade chord length gauge design method, which takes the X axis and Y axis of a blade as original reference, forms an L axis by an angle alpha between a measured size of the blade and the X axis, and sets a lower end measurement starting point of the measured size on a blade tail arc of the blade; selects three points A, B and C on the blade as reference design gauge plate shapes, the A reference and the C reference are straight line positioning respectively, the B reference is curve positioning, and a size measurement baseline of the blade is parallel to a reference axis of the measured size; calculates shape precision of the gauge plate, obtains sizes and curve point coordinates of the A reference, the B reference and the C reference; realizes self-positioning of the gauge plate and the blade by finding corresponding positioning of the A reference, the B reference and the C reference on the gauge plate, realizes quick and accurate measurement on site in batch production of chord lengths of blades with different shapes or sizes, and is low in cost.

Description

Technical Field

[0001] This invention relates to the technical field of blade chord length measurement, and specifically to a design method for a conformal self-positioning blade chord length gauge. Background Technology

[0002] Chord length measurement of aero-engine blades is a frequent requirement in blade manufacturing. Chord length gauges are a commonly used tool in mass production for quick and convenient measurement. Some gauges require specialized measuring instruments and offer accurate measurements, but are costly to manufacture and inflexible in application. Others are handheld, low-cost, and flexible, but unsuitable for certain scenarios. For example, when the reference axis of the measured dimension forms an angle with the gauge's reference axis, handheld gauges may not yield accurate results.

[0003] Therefore, there is currently a lack of a method for measuring blade chord length that is both cost-effective and convenient. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a design method for a conformal self-positioning blade chord length gauge, which solves the technical problems of high manufacturing costs or inflexible application scenarios in blade chord length measurement in existing technologies.

[0005] This invention provides a method for designing a conformal self-positioning blade chord length gauge, comprising:

[0006] S1. Using the X-axis and Y-axis of the blade as the original reference, the angle α between the measurement axis of the measured dimension of the blade and the X-axis forms the L-axis, and the lower measurement starting point of the measured dimension is set on the blade tip arc.

[0007] S2. Select three points A, B, and C on the blade as references to design the shape of the clamping plate. Reference points A and C are positioned by straight lines, and reference point B is positioned by a curve, so that the baseline of the clamping plate is parallel to the reference axis of the dimension to be measured.

[0008] S3. Calculate the shape accuracy of the card plate, and obtain the dimensions and curve point coordinates of the A reference, B reference and C reference;

[0009] S4. By making a straight line segment tangent to reference A on the clamping plate, the clamping plate is positioned at reference A; by making a short curved line segment coupled to reference B on the clamping plate, the clamping plate is positioned at reference B; by making a straight line segment tangent to the blade shape at the point where the clamping plate corresponds to reference C, the clamping plate is positioned at reference C. This achieves self-positioning of the clamping plate and the blade, and the clamping plate is used to complete the measurement of the blade chord length.

[0010] Optionally, the lower measurement starting point of the measured dimension is located on the blade tip arc, including:

[0011] The lower measurement starting point of the measured dimension is set at the tangent point of the trailing edge arc R0.25 of the blade.

[0012] Optionally, the step of selecting three points A, B, and C on the blade as references to design the shape of the card plate, wherein references A and C are respectively positioned by two straight lines, and reference B is positioned by a curve, includes:

[0013] The A reference is the point of tangency between the boundary line of the card plate and the blade tip arc; the B reference is a curve segment selected near the A reference point tangent to the blade tip arc; and the C reference is the point where the parallel line of the L axis is tangent to the curve of the blade.

[0014] Optionally, obtaining the dimensions and curve point coordinates of the A, B, and C datums includes:

[0015] The lengths of the reference datums A, B, and C are all selected between 8 and 35 mm, and the positional accuracy of the reference datums A, B, and C is ±0.01 mm.

[0016] Optionally, the card plate is designed as one through-end card plate and one stop-end card plate.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] This invention addresses the issue of measuring the chord length of blades of different shapes or sizes in mass production by manufacturing a chord length clamp that matches the blade, enabling rapid and accurate measurement on-site, while also reducing manufacturing and maintenance costs. Attached Figure Description

[0019] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the process of the present invention;

[0022] Figure 2 This is a schematic diagram of the measured dimension and included angle α in this invention;

[0023] Figure 3 This is a schematic diagram of the shape and dimension boundary of the lower blade of the measured dimension in this invention;

[0024] Figure 4 This is a schematic diagram of datum A, datum B (or datum B1), datum C (or datum C1), and axis L in this invention;

[0025] Figure 5 This is a schematic diagram of the leaf-bowl orientation measuring plate in this invention;

[0026] Figure 6 This is a schematic diagram of the blade back direction measuring plate in this invention;

[0027] Figure 7 This is a schematic diagram illustrating the dimensional relationship of positioning point A in this invention;

[0028] Figure 8 This is a schematic diagram of point O, point O1, the XOY coordinate system, and the LOM coordinate system in this invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Functional units with the same reference numerals in the examples of this invention have the same and similar structures and functions.

[0030] See Figure 1 This invention provides a method for designing a conformal self-positioning blade chord length gauge, comprising:

[0031] S1. Using the X-axis and Y-axis of the blade as the original reference, the angle α between the measurement axis of the measured dimension of the blade and the X-axis forms the L-axis, and the lower measurement starting point of the measured dimension is set on the blade tip arc.

[0032] S2. Select three points A, B, and C on the blade as references to design the shape of the clamping plate. Reference points A and C are positioned by straight lines, and reference point B is positioned by a curve, so that the baseline of the clamping plate is parallel to the reference axis of the dimension to be measured.

[0033] S3. Calculate the shape accuracy of the card plate, and obtain the dimensions and curve point coordinates of the A reference, B reference and C reference;

[0034] S4. By making a straight line segment tangent to reference A on the clamping plate, the clamping plate is positioned at reference A; by making a short curved line segment coupled to reference B on the clamping plate, the clamping plate is positioned at reference B; by making a straight line segment tangent to the blade shape at the point where the clamping plate corresponds to reference C, the clamping plate is positioned at reference C. This achieves self-positioning of the clamping plate and the blade, that is, the measurement axis of the measured dimension is parallel to the measurement baseline of the clamping plate, thereby completing the measurement of the blade chord length.

[0035] See Figure 2 - Figure 5 In this embodiment, the datum reflects the blade design requirements and serves as the basis for the design, manufacturing, and inspection of the clamping plate. The blade design datum is the X and Y axes. The angle α between the measurement axis of the measured dimension and the X axis forms the L axis, and the lower measurement starting point of the measured dimension is set at the tangent point of the trailing edge arc R0.25 of the blade.

[0036] Revised to: Further, the clamping plate needs to be designed first. Three points A, B, and C are selected on the blade as references for designing the clamping plate shape. Reference points A and C (or C1) are positioned by straight lines, while reference point B (or B1) is positioned by a curve. The baseline for measuring the clamping plate dimensions is parallel to the reference axis of the dimension being measured. Reference point A is the tangent point between the clamping plate's boundary line and the blade's tail arc. Reference point B is a small curve segment selected near reference point A, which is tangent to the blade's tail arc. Reference point C is the point where the line parallel to the L-axis is tangent to the curve of the blade. The dimensions and coordinates of reference points A, B, and C are calculated to two decimal places. See [link to relevant documentation]. Figure 6 and Figure 7 Taking benchmark A as an example, the calculation process is explained as follows:

[0037] First, find the coordinates of the center of the circle with radius R0.25:

[0038] The center of the circle with radius R = 1.2 - 0.25 is located at the intersection of the circle with radius R = 1.2 - 0.25 and the parallel line that is 0.25 away from the line H and deviates from point O.

[0039] Equation of a circle: X 2 +Y 2 =R 2 ;

[0040] The equation of the straight line is: Y = Xtg20° - (0.55 - 0.25)cos20°;

[0041] Solve the equation; the coordinates of the circle's center are (0.95, 0.03).

[0042] Coordinate transformation, rotation β = (180° - 57°41′43″);

[0043] X=Xcosβ+Ysinβ, Y=-Xsinβ+cosβ;

[0044] The center coordinates of the circle in the LOM coordinate system are (-0.48, -0.82).

[0045] The coordinates of point A in the LOM coordinate system are (-0.73, -0.82).

[0046] Based on the aforementioned calculation process, the length dimensions of the A, B, and C references are all selected to be between 8 and 35 mm, and the positional accuracy of the A, B, and C references is ±0.01 mm. This confirms that the card plate is a plate-shaped irregular structure with parallel front sides.

[0047] Finally, a straight line segment tangent to reference A is made on the card plate at the position corresponding to reference A, so that the card plate is positioned at reference A; a short curved line segment coupled to reference B is made on the card plate at the position corresponding to reference B, so that the card plate is positioned at reference B; a straight line segment tangent to the blade shape is made on the card plate at the position corresponding to reference C, so that the card plate is positioned at reference C. This achieves the self-positioning of the card plate and the blade, that is, the measurement axis of the measured dimension is parallel to the baseline of the card plate dimension measurement, thereby completing the dimension measurement of the blade chord length. When the card plate is brought close to the blade as shown in the figure, there is no gap at the three references A, B, and C. If the through end passes through and the stop end does not pass through, then the blade chord length is qualified; otherwise, it is unqualified. This enables fast and accurate measurement of the chord length of blades of different shapes or sizes in mass production, and the manufacturing and maintenance costs are low.

[0048] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0049] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A design method for a conformal self-positioning blade chord length gauge, characterized in that, include: S1. The design reference of the blade is the X-axis and Y-axis. Taking the X-axis and Y-axis as the original reference, the angle α between the measurement axis of the blade chord length and the X-axis forms the L-axis, and the lower end measurement starting point of the chord length is set at the tangent point of the blade tip arc R0.

25. S2. Select three points A, B, and C on the blade as references to design the shape of the clamping plate. Reference A and reference C are positioned by straight lines, and reference B is positioned by a curve. Reference A is the point of tangency between the boundary line of the clamping plate and the blade tail arc. Reference B is a section of curve selected near reference A, which is tangent to the blade tail arc. Reference C is the point where the line parallel to the L-axis is tangent to the curve of the blade, so that the baseline for measuring the size of the clamping plate is parallel to the axis for measuring the chord length. S3. Calculate the shape accuracy of the card plate, and obtain the point coordinates of the A reference and C reference, as well as the curve point coordinates of the B reference; S4. By making a straight line segment tangent to reference A on the card plate, the card plate is positioned at reference A. A short curved segment is made on the clamping plate corresponding to reference B, so that the clamping plate is positioned at reference B; a straight line segment tangent to the airfoil is made on the clamping plate corresponding to reference C, so that the clamping plate is positioned at reference C, thus realizing the self-positioning of the clamping plate and the blade. The clamping plate is used to complete the dimensional measurement of the blade chord length. The clamping plate is designed to have one through end clamping plate and one stop end clamping plate. When the clamping plate is close to the blade, there is no gap at the three reference points A, B, and C. If the through end passes through and the stop end does not pass through, then the blade chord length is qualified; otherwise, it is unqualified.

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