A radius measuring device and method for an arc-shaped blade.

Abstract

This invention discloses a radius measuring device for arc-shaped blades. During measurement, the device is positioned relative to the blade in a distance. It consists of three optical rangefinders, a scale, a base, and a support. Each optical rangefinder is independently mounted to the outer end of a fixed connecting handle. The inner ends of the three fixed connecting handles are pivotally connected to the center of the scale, with adjustable tightness. The probe faces of the three optical rangefinders are equidistant from the center, and the projection angles of the measuring rays onto the scale plane are staggered and adjustable. The radius of the arc-shaped blade can be calculated by intuitively reading the included angles and the distance measurement results. This radius measurement solution eliminates the need for actual contact with the blade during measurement; it offers a wider range of sizes and higher accuracy, improving the flexibility of inward / outward selection for measuring the radius of such blades. It is applicable to various spatial scenarios, and the measurement results are intuitive and efficient.

Description

Technical Field

[0001] This invention relates to a non-contact measurement technology solution, and more particularly to a non-contact measurement device and method for obtaining the radius of a circular arc blade. Background Technology

[0002] Impellers are core components in rotating fluid machinery such as fans and pumps. The performance curves and parameters commonly referred to in the context of fans and pumps primarily refer to the hydraulic performance of the impeller. The main factor determining this hydraulic performance is the shape of the internal flow channels, and the shape of the blades is a crucial factor in this flow channel shape. For arc-shaped blades, the radius of the arc directly determines the blade shape, thus affecting the shape of the internal flow channels, consequently influencing the impeller's hydraulic performance, and ultimately determining whether the overall machine's performance meets the usage requirements. Therefore, after the impeller blades are manufactured, their radius must be checked before assembly and welding to determine if the manufacturing error of the blade's arc radius is within the allowable range.

[0003] Currently, the closest measurement method is the rolling measurement along a circular arc. However, this measurement technique is cumbersome to operate, the measuring tool needs to contact the actual surface of the blade, making it difficult to avoid large operational errors, and the time required for a single measurement is also relatively long. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention aims to provide a radius measuring device and method for arc-shaped blades, so as to efficiently, conveniently, and with high precision acquire the arc radius of the blades.

[0005] The technical solution of the present invention to achieve the above-mentioned objective is as follows: a radius measuring device for an arc-shaped blade, which is positioned relative to the blade to be measured in the air. Its features include: it is composed of three optical rangefinders, a scale, a base pad, and a support pad. Each optical rangefinder is independently mounted on the outer end of a fixed connecting handle. The inner ends of the three fixed connecting handles are pivotally connected to the center of the scale and the tightness is adjustable. The probe end faces of the three optical rangefinders are equidistant from the center, and the projection angles of the measuring rays of the three optical rangefinders in the plane of the scale are staggered and the included angle is adjustable. The base pad is fixedly mounted to the scale and, in the measurement and use state, abuts against a radial plane reference object of the blade to be measured, keeping the three measuring rays parallel to the radial plane.

[0006] The aforementioned radius measuring device for the arc-shaped blade further includes a pair of parallel blades at the inner end of each of the fixed connecting handles, which are spaced apart and opposite each other. The spacing between the parallel blades of the three fixed connecting handles is staggered and can be stacked one by one. In the assembled state, the equal diameter perforations of each parallel blade are coaxially connected.

[0007] Furthermore, in the aforementioned radius measuring device for the arc-shaped blade, a damping layer or ratchet is attached between the contact surfaces of the nested parallel blades.

[0008] Furthermore, the aforementioned radius measuring device for the arc-shaped blade has a limiting sleeve sandwiched between the innermost pair of nested parallel blades, which is coaxially connected to the perforation.

[0009] The aforementioned radius measuring device for the arc-shaped blade further includes a connecting sleeve that serves as a pivot. The connecting sleeve passes through the center of the dial and the outer ends of each fixed connecting handle, and fastening bolts and nuts pass through both ends of the connecting sleeve. Any optical rangefinder can rotate and be positioned and locked around the fixed axis of the connecting sleeve.

[0010] Furthermore, in the aforementioned radius measuring device for arc-shaped blades, the bottom pad is integrally formed with a collar, and is integrally pivotally connected to the center of the circle via the collar.

[0011] The aforementioned radius measuring device for the arc-shaped blade further includes a data processing unit, which is at least a programmable micro calculator or computing medium. The included angle data and detection results of the three rangefinders are transmitted and interacted with the data processing unit via data lead-out lines or wireless signals. The data processing unit is either separate from or integrated with the main body of the radius measuring device.

[0012] The technical solution of the present invention to achieve another objective mentioned above is: a method for measuring the radius of an arc-shaped blade, based on the aforementioned radius measuring device, characterized by comprising the following steps:

[0013] S1. Place the radius measuring device facing the blade to be measured, and adjust the sway angle of each optical rangefinder so that the measuring rays are all within the width of the blade to be measured. Read the included angles α and β between two adjacent optical rangefinders through the scale.

[0014] S2. Using an optical rangefinder, measure the distance between the measuring ray and the blade to be measured at three points A, B, and C, as well as the distance D of each intersection point relative to the center H of the scale. HA D HB D HC ;

[0015] S3. Construct an orthogonal coordinate system in the radial plane containing the ranging ray, and obtain three intersection points A, B, and C, and the corresponding three chords L. AB L AC L BC Coordinates of their respective midpoints: A(x) A y A ), B(x B y B ), C(x) C yC M AB (x) MAB y MAB M AC (x) MAC y MAC M BC (x) MBC y MBC ); obtain each chord L sequentially through each coordinate point. AB L AC L BC The equation of the straight line, the perpendicular line L from the midpoint of each chord ⊥AB L ⊥AC L ⊥BC The equation of the straight line is obtained, and then the second center O(x) of the radial plane of the blade under test is obtained through the intersection of the perpendicular lines from the midpoints of any two chords. O y O ) and its distance relative to any intersection point A, B or C.

[0016] The above-mentioned method for measuring the radius of the arc-shaped blade further includes an orthogonal coordinate system constructed with the center H of the scale circle as the origin and the y-axis being the direction HB of the ranging ray pointing to the intersection point B.

[0017] In the above-mentioned method for measuring the radius of an arc-shaped blade, the radius measuring device is placed facing the concave or convex arc surface of the blade to be measured and the distance is measured.

[0018] Compared to traditional circular arc radius measurement methods, the radius measurement device and method of this invention have outstanding substantive features and significant advancements: 1. By using an optical rangefinder to measure the distance to the blade under test, the distance data required for calculating the circular arc radius is obtained, and the measurement process does not require actual contact with the blade; 2. Reduced constraints result in a wider measurement range and higher accuracy, overcoming the errors of manual measurement operations; 3. It can be applied to measuring the inner or outer side of circular arc blades, improving the flexibility of radius measurement for such blades; 4. The calculation process of the measurement results is easy to program and can be completed using a programmable data processing unit. Combined with an external display unit, the instantaneous and accurate radius measurement results can be obtained intuitively; 5. Through diverse connection, communication, and integration methods between the radius measurement device and the data processing unit, it can flexibly adapt to measurement applications in various spatial scenarios. Attached Figure Description

[0019] Figure 1 This is a front view schematic diagram of the radius measuring device of the present invention.

[0020] Figure 2 yes Figure 1 A side view of the radius measuring device shown.

[0021] Figure 3 This is a schematic diagram illustrating one implementation of radius measurement using the radius measuring device of the present invention.

[0022] Figure 4 This is a schematic diagram illustrating another implementation of radius measurement using the radius measuring device of the present invention. Implementation

[0023] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, so as to make the technical solution of the present invention easier to understand and master, and thus to make a clearer definition of the scope of protection of the present invention.

[0024] This invention provides a radius measuring device with simple structure, convenient assembly and operation, wide measurement range, and small measurement error, as well as a radius measuring method for arc-shaped blades. It can measure not only the inner arc of the blade but also the outer arc of the blade, improving the flexibility of measurement operations.

[0025] Understanding the structural composition and functional design of the radius measuring device, such as... Figure 1 and Figure 2 As shown in the structural diagrams from different perspectives, the main body consists of three optical rangefinders 1, 2, and 4, a scale 5, a base pad 6, and a support pad 11. Each optical rangefinder is independently mounted on the outer end of a fixed connecting handle 3. The inner ends of the three fixed connecting handles 3 are pivotally connected to the scale 5 at the center H of the scale, and the tightness is adjustable. The probe end faces K1, K2, and K3 of the three optical rangefinders are equidistant from the center H, and the projection angles of the ranging rays of the three optical rangefinders onto the plane of the scale are staggered and the included angles are adjustable. This part mainly enables the three optical rangefinders to freely open and close within the angle range of the scale to adjust the opening angle, and to quickly and stably lock when a suitable opening angle is reached. In addition, the base pad 6 is fixed to the dial 5 near the center H, and the support pad 11 is fixed to the dial 5 at the scale arc edge away from the center H. When in use, the base pad 6 and the support pad 11 are together against any radial plane reference M of the blade 99 to be measured. Their purpose is to ensure that the three ranging rays are parallel to the radial plane and irradiate the blade surface for accurate ranging.

[0026] The above summary scheme illustrates that, due to the significant differences in the radius and width of the blades being measured, setting a reasonable opening range for the optical rangefinders is crucial for the convenience of subsequent measurement methods and calculations. For blades with wider widths, the opening angle range can be appropriately increased, while for blades with narrower widths, the opening angle range can be appropriately decreased to ensure that each optical rangefinder can obtain reliable readings. In practical applications, to accommodate the measurement of blades with various arc radii, the aforementioned scale radius and fixed connecting handle length also need to be equipped with replaceable parts of different specifications to meet different distance specifications between the probe end face and the center H of the scale. However, under any specification, it is still necessary to ensure that the probe end faces of the three optical rangefinders are equidistant from the center. Here, the preferred number of optical rangefinders is three, because radius measurement cannot be achieved with only two optical rangefinders, and using more optical rangefinders, in addition to increasing equipment costs and reducing operational convenience, also significantly increases the computational complexity.

[0027] The following, in conjunction with the preferred embodiment illustrated, further demonstrates the detailed features of the radius measuring device: Each of the aforementioned fixed connecting handles 3 has a pair of parallel wing plates positioned opposite each other at its inner end, and the spacing between the parallel wing plates of the three fixed connecting handles is staggered sequentially, allowing them to be stacked one after another. In the assembled state, the equal-diameter perforations on each parallel wing plate are coaxially connected. For example... Figure 2 As shown in the middle section, the distance between a pair of parallel blades 31 corresponding to the fixed handle 3 of the first optical rangefinder 1 is the smallest, and the distance between a pair of parallel blades 34 corresponding to the fixed handle 3 of the second optical rangefinder 4 is the largest. Thus, the distance between the parallel blades 32 is in the middle.

[0028] Considering the structural strength deficiencies of the parallel wing plates as fixed connecting handles, to prevent displacement or deformation of the individual fixed connecting handles, a limiting sleeve 9, coaxially connected to the perforation, is sandwiched between the innermost pair of nested parallel wing plates. The aforementioned pivot connection is achieved by a connecting sleeve 8 serving as a pivot, which passes through the center of the scale 5 and the outer ends of each fixed connecting handle. Fastening bolts 10 and fastening nuts 7 are connected to both ends of the connecting sleeve 8, allowing any optical rangefinder to rotate and lock in position around the fixed axis of the connecting sleeve 8. In the illustrated embodiment, for assembly, the base pad 6 is integrally formed with a collar 61, which is integrally pivotally connected to the center.

[0029] From the assembly process: First, the parallel wing plate 32 is stacked on the outer periphery of the parallel wing plate 31 and aligned with the through holes. Then, the parallel wing plate 34 is stacked on the outer periphery of the parallel wing plate 32 and aligned with the through holes. Next, the limiting sleeve 9 is inserted between the parallel wing plates 31. Then, the connecting sleeve 8 is passed through the through holes and the limiting sleeve 9 in one direction. After the dial 5 and the bottom pad 6 are respectively attached to the exposed parts at both ends, the fastening bolts 10 and nuts 7 are installed at both ends to limit and fix the adjustable tightness of each part of the connecting sleeve.

[0030] In addition to the structural design of the preferred embodiment described above, although the axial clamping force is applied by tightening bolts and nuts, the sliding resistance between the parallel blades is still relatively small; after adjusting the included angle, changes in the included angle during the measurement process are still inevitable, affecting the accuracy of the radius measurement results. Therefore, an improvement can be made by attaching a damping layer or ratchet between the contact surfaces of the nested parallel blades, thereby ensuring the stability of the included angle positioning between the optical sequencers without external force.

[0031] The main body of the aforementioned radius measuring device can be used alone to measure arc-shaped blades, and the radius result can be obtained through manual calculation. Alternatively, it can rely on a data processing unit to perform the calculation function. Therefore, the radius measuring device also includes a data processing unit, which is at least a programmable microcomputer or computing medium. The angle data and detection results from the three rangefinders are transmitted to the data processing unit via data cables or wireless signals. This data processing unit can be either separate from or integrated into the main body of the radius measuring device.

[0032] To understand the functionality of the radius measuring device of the present invention, the following illustrations and detailed descriptions demonstrate the specific measurement method, which mainly includes the following steps.

[0033] S1. Place the radius measuring device facing the blade to be measured, and adjust the tilt angle of each optical rangefinder so that the measuring rays are all within the width of the blade. Read the included angles α and β between adjacent pairs of the three optical rangefinders using the scale. This part is largely the preliminary preparation work for the measurement. First, it is necessary to ensure that the radius measuring device (the direction of the three measuring rays) remains parallel to the radial plane of the blade to be measured under the support of the base. At the same time, it is necessary to ensure that each optical rangefinder can illuminate the coverage area of ​​the blade to be measured. In the diagram, the included angle α is the angle between the measuring rays of the two adjacent optical rangefinders on the left, and the included angle β is the angle between the measuring rays of the two adjacent optical rangefinders on the right.

[0034] S2. Start the measuring device and use the optical rangefinder to measure the distance between the measuring ray and the blade under test at 99°. Obtain the three intersection points A, B, and C between the measuring ray and the blade under test, as well as the distance D of each intersection point relative to the center H of the scale. HA D HB D HC Here, the three distances can be obtained by summing the optical rangefinder readings with the distance between the probe end face and the center H of the circle; the latter is usually a known value.

[0035] S3. After obtaining the basic data such as the included angle and the distance to the blade being measured, substantial computational processing is required based on this data to obtain the radius result from multiple computational levels. The algorithm overview includes constructing an orthogonal coordinate system in the radial plane where the ranging ray is located, and obtaining three intersection points A, B, and C, and the corresponding three chords L. AB L AC L BC Coordinates of their respective midpoints: A(x) A y A ), B(x B y B ), C(x) C y C M AB (x) MAB y MAB M AC (x) MAC y MAC M BC (x) MBC y MBC ); obtain each chord L sequentially through each coordinate point. AB L AC L BC The equation of the straight line, the perpendicular line L from the midpoint of each chord ⊥AB L ⊥AC L ⊥BC The equation of the straight line is obtained, and then the second center O(x) of the radial plane of the blade under test is obtained through the intersection of the perpendicular lines from the midpoints of any two chords. O y O ) and its distance relative to any intersection point A, B or C.

[0036] Combination Figure 3 The illustrated implementation involves measurements taken inside the arc-shaped blade. Furthermore, the aforementioned orthogonal coordinate system is constructed with the center H of the scale circle as the origin and the direction HB of the ranging ray pointing to the intersection point B as the y-axis. Logically, the x-axis lies within the radial plane containing the ranging ray, passing through the center H of the scale circle and perpendicular to the direction HB of the ranging ray. Given the three known distances D... HA D HB D HC Given the values ​​of the two included angles α and β, the coordinates of the intersection points A, B, or C can be calculated (using basic plane geometry algorithms). Then, the straight line L between any two points can be derived from the coordinates of intersection points A, B, and C. AB L AC L BC The equation and the coordinates of the midpoint M of the corresponding line AB M AC M BC straight line L AB LAC L BC That is, the lines containing the three chords AB, AC, and BC on the arc; then, the line L AB L AC L BC The equation and the corresponding midpoint coordinates M AB M AC M BC We can obtain the perpendicular line L passing through the midpoint of each of the three chords. ⊥AB L ⊥AC L ⊥BC The equation is the equation of the straight line corresponding to the radii of the three chords. Taking any two straight lines with radii, the intersection point is the center point O(x) of the radial plane of the blade to be measured. o y o By connecting the center O of the circle with any intersection point on the arc, the distance between any two points OA, OB, or OC can be obtained. This distance is the radius R of the arc blade that needs to be measured.

[0037] The calculation methods described above are not the focus of this invention. The measurement method is merely a theoretical application and development of existing calculation methods. It can be performed manually or programmed into a micro calculator or other computing medium. Simultaneously, data from the three optical rangefinders are connected to the data processing unit via data cables or wireless transmission for calculation, providing immediate measurement results. Alternatively, the data processing unit, combined with the display and the main body of the radius measuring device, can be integrated into one unit for greater convenience.

[0038] In addition to the above-described implementation method of placing the measuring device on the concave arc surface facing the blade to be measured and performing distance measurement, such as Figure 4 As shown, the measurement method of the present invention can also be implemented for measuring the convex arc surface (i.e., the outer arc) of the blade to be measured. The calculation process after obtaining the distance measurement result is basically the same as described above, so it is omitted here.

[0039] In summary, the detailed description of the arc-shaped blade radius measuring device and method of the present invention, combined with the illustrated embodiments, demonstrates that this solution possesses several significant advantages, summarized as follows: 1. By employing an optical rangefinder to measure the distance to the blade under test, the distance data required for calculating the arc radius is obtained, and the measurement process does not require actual contact with the blade; 2. Reduced constraints result in a wider measurement range and higher accuracy, overcoming errors inherent in manual measurement operations; 3. It can be applied to measurements facing the inner or outer side of the arc-shaped blade, improving the flexibility of radius measurement for such blades; 4. The calculation process of the measurement results is easily programmed and completed using a programmable data processing unit, and combined with an external display unit, it can intuitively obtain real-time and accurate radius measurement results; 5. Through diverse connection, communication, and integration methods between the radius measuring device and the data processing unit, it flexibly adapts to measurement applications in various spatial scenarios.

[0040] In addition to the above embodiments, the present invention may have other implementation methods. All technical solutions formed by equivalent substitution or equivalent transformation fall within the scope of protection claimed by the present invention.

Claims

1. A device for measuring the radius of a circular-arc vane, which is positioned opposite the vane to be measured, characterized in that: The radius measuring device is composed of three optical distance meters, a dial plate, and a bottom pad and a support pad, wherein each optical distance meter is independently attached to the outer end of a fixed connecting handle, the inner end of the three fixed connecting handles is pivotally connected to the center of the dial plate with adjustable tightness, the probe end faces of the three optical distance meters are equidistantly arranged relative to the center, and the projection angles of the ranging ray directions of the three optical distance meters in the dial plate plane are mutually staggered and adjustable.

2. The apparatus for measuring the radius of a circular-arc blade according to claim 1, wherein: Each fixed connecting handle is provided with a pair of spaced apart parallel wing plates at the inner end, and the spacing of the parallel wing plates of the three fixed connecting handles is staggered and can be overlapped one by one.

3. The apparatus for measuring the radius of a circular-arc blade according to claim 2, wherein: A damping layer or a ratchet is attached between the contact surfaces of the overlapped parallel wing plates.

4. The apparatus for measuring the radius of a circular-arc blade according to claim 2, wherein: A limiting sleeve coaxially penetrating the perforations is clamped between the overlapped and innermost pair of parallel wing plates.

5. The apparatus for measuring the radius of a circular-arc blade according to claim 1, wherein: A connecting sleeve serving as a pivot is provided, the connecting sleeve penetrates the center of the dial plate and the outer end of each fixed connecting handle, and the connecting sleeve is provided with a fastening bolt and a nut at both ends.

6. The apparatus for measuring the radius of a circular-arc blade according to claim 1, wherein: The bottom pad is integrally formed with a sleeve ring and is integrally pivotally connected to the center.

7. A method for measuring the radius of a circular arc blade, implemented based on the radius measuring device according to any one of claims 1 to 6, characterized in that The steps include: S1, place the radius measuring device facing the blade to be measured, and adjust the deflection angle of each optical distance meter so that the ranging rays are within the range of the blade to be measured, and read the included angles α and β between the two adjacent optical distance meters on the dial plate; S2, ranging to the blade to be measured by the optical range finder, obtaining three intersection points A, B, C of the ranging ray and the blade to be measured, and the distance D of each intersection point relative to the center H of the scale disc HA , D HB , D HC ; S3, Construct an orthogonal coordinate system in the radial plane where the ranging ray is located, and obtain three intersection points A, B, and C and three corresponding chords L AB 、 AC 、 BC The coordinates of the respective midpoints are: A (x A , y A ), B (x B , y B ), C (x C , y C ), M AB (x MAB , y MAB ), M AC (x MAC , y MAC ), and M BC (x MBC , y MBC ); the straight line equations of each chord L AB 、 AC 、 BC , the straight line equations of the perpendiculars L ⊥AB 、 ⊥AC 、 ⊥BC of the midpoints of each chord, and the second circle center o (x o , y o ) of the radial plane of the blade to be measured and its distance relative to any intersection point A, B, or C are obtained through the intersection of any two perpendiculars of the midpoints of the chords.

8. The method of claim 7, wherein: The orthogonal coordinate system is constructed with the center H of the dial plate as the coordinate origin and the ranging ray direction HB pointing to the intersection point B as the y-axis.

9. The method of claim 7, wherein: The radius measuring device is placed facing the concave or convex surface of the blade to be measured for distance measurement.

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