CN106643619B - Propeller blade thickness measuring device, measuring system and measuring method - Google Patents

Abstract

The invention discloses a propeller blade thickness measurement device, a measurement system and a measurement method, comprising a U-shaped attachment; the two ends of the U-shaped attachment are respectively a fixed end and a measurement end; the inner side of the fixed end of the U-shaped attachment is provided with a supporting foot, The outer side is provided with a spring top shell; the support foot is a three-leg bracket, the bottoms of the three legs of the support foot are located on the same horizontal plane A, and the connection line between the bottoms of the three legs is an equilateral triangle. The propeller blade thickness measuring device, measuring system and measuring method of the present invention have the advantages of simple structure, low cost and accurate measurement.

Description

Propeller blade thickness measuring device, measuring system and measuring method

technical field

The invention relates to a low-cost propeller blade thickness rapid measuring device, a measuring system and a measuring method.

Background technique

At present, for the measurement of the thickness of the propeller blade, the dimension to be measured is to measure the thickness of a certain point on the blade surface along the normal direction. The key to solving the problem is to find the normal direction of the specified point, but the existing measurement devices and equipment are very complicated. , hardware and software equipment is expensive.

In particular, the point cloud data of the blade casting is obtained by using a 3D scanner, and the measurement of the blade thickness is realized in the software. Although the accuracy of this method is high, the measurement cost is high and the measurement efficiency is low, which makes the enterprise face the embarrassing situation that the measurement cost is much higher than the profit of the parts.

Therefore, it has become an urgent problem to be solved to develop a measurement device that can complete the measurement, with simple equipment and low cost.

SUMMARY OF THE INVENTION

According to the technical problem proposed above, a propeller blade thickness measurement device, measurement system and measurement method are provided, which are used to solve the shortcomings of the existing measurement device, the equipment is very complicated, and the hardware and software equipment is expensive. The technical means adopted in the present invention are as follows:

A propeller blade thickness measuring device, comprising a U-shaped attachment; the two ends of the U-shaped attachment are a fixed end and a measuring end respectively; the inner side of the fixed end of the U-shaped attachment is provided with a support foot, and the outer side is provided with a spring tip shell; The outrigger is a three-leg bracket, the bottoms of the three outriggers of the outrigger are located on the same horizontal plane A, and the line connecting the bottoms of the three outriggers is an equilateral triangle.

A spring tip is arranged in the spring tip housing, and a spring is arranged between the spring tip and the inner wall of the spring tip housing, so that the front end of the spring tip can pass through the fixed end of the U-shaped attachment and extend to the legs of the support feet. bottom; the axis where the top of the spring is located is perpendicular to the horizontal plane A where the bottom of the support leg is located; the measuring end of the U-shaped accessory is detachably connected with a screw micrometer, and the front end of the screw micrometer is provided with a lower top; the The spring top and the lower top are coaxially arranged, and the tips are oppositely arranged.

Preferably, the spring tip is provided with an annular protrusion on the side close to the support foot, so that one end of the spring is pressed against the annular protrusion, and the other end is pressed against the inner wall of the spring tip housing.

As the preferred screw micrometer, the outer wall of the installation section is screwed with the measuring end of the U-shaped accessory.

A measurement system, comprising a blade point-to-be-measured positioning device and a blade point-to-be-measured thickness detection device; the blade point-to-be-measured thickness detection device is the above-mentioned propeller blade thickness measurement device; the blade point-to-be-measured positioning device includes a Center column, semiconductor laser transmitter, three-jaw chuck and rotating arm.

The three-jaw chuck is sandwiched with a propeller, and the upper surface of the three-jaw chuck has an indexing plate; the centering column is arranged on the outside of the three-jaw chuck, and the centering column includes a vertical setting The support part and the fixed part arranged horizontally; the fixed part of the centering column is provided with a rotating arm, the center of the rotating arm is rotatably connected with the fixed part, and the center of the rotating arm is coaxial with the axis of the blade of the propeller; The end of the arm is provided with a semiconductor laser transmitter for indicating the position of the point to be measured in real time; the thickness detection device for the point to be measured of the blade can measure the thickness of the point to be measured indicated by the semiconductor laser transmitter.

Preferably, the fixed part of the centering column is vertically connected with the top end of the support part.

Preferably, when the rotating arm rotates relative to the center of the rotating arm, the semiconductor laser transmitter can rotate in a circle of R190.

A measurement method using the above measurement system, comprising the following steps:

S1. Clamp the propeller on the three-jaw chuck of the blade to-be-measured point positioning device.

S2. Rotate the rotating arm so that the light spot of the semiconductor laser transmitter falls on the edge of the blade of the propeller, and mark the laser spot, that is, the point to be measured, point C1.

S3. Rotate the three-jaw chuck with an indexing plate by 16° in turn. Similarly, mark the points to be measured, C2 and C3, on the blade surface of the propeller.

S4. Use the thickness detection device of the point to be measured on the blade to measure the thickness values of the points to be measured, C1, C2, and C3 in turn.

The measurement as preferred S4 specifically includes the following steps:

S41. Coincide the top of the spring with the point to be measured.

S42. Adjust the support feet so that they are stably supported on the curved surface of the blades of the propeller.

S43. Rotate the spiral micrometer to make the lower tip in close contact with the lower surface of the blade, and read out the reading.

S44, repeat the measurement three times, record the data, and calculate the average value as the thickness of the propeller blade at this point.

Compared with the prior art, in the propeller blade thickness measurement device, the measurement system and the measurement method of the present invention, the legs of the propeller blade thickness measurement device are three-leg brackets, and the bottoms of the three legs of the legs are located on the same horizontal plane A, And the connection line of the bottom of the three legs is an equilateral triangle; the axis where the top of the spring is located is perpendicular to the horizontal plane A where the bottom of the legs is located; the measuring device is simple in structure, low in cost and accurate in measurement.

Description of drawings

The present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

FIG. 1 is a schematic structural diagram of a propeller blade thickness measuring device of the present invention.

Figure 2 is a schematic diagram of the measurement system of the present invention.

Figure 3 is a schematic view of a propeller blade of the present invention.

FIG. 4 is a schematic diagram of a propeller blade thickness measuring device of the present invention.

Fig. 5 is a schematic view of a foot of the present invention.

Figure 6 is a schematic view of the spring tip housing and the spring tip of the present invention.

FIG. 7 is a working schematic diagram of the propeller blade thickness measuring device of the present invention.

FIG. 8 is a schematic diagram of the measurement of the normal in the engineering practice of the present invention.

FIG. 9 is a schematic diagram of the principle of normal line measurement in the present invention.

FIG. 10 is a color display diagram of the Gaussian curvature of the present invention.

FIG. 11 is a schematic diagram of the position of the point to be measured on the propeller blade of the present invention.

Figure 12 is a schematic diagram of an equilateral triangle taken in the vicinity of the propeller blade of the present invention.

FIG. 13 is a graph of measurement data at C1 of the present invention (θ=0°).

FIG. 14 is a line graph of the measurement data at C1 of the present invention (θ=0°).

FIG. 15 is a graph of the measurement data at C1 of the present invention (θ=30°).

Fig. 16 is a line graph of the measurement data at C1 of the present invention (θ=30°).

FIG. 17 is a graph of the measurement data at C1 of the present invention (θ=60°).

Fig. 18 is a line graph of the measurement data at C1 of the present invention (θ=60°).

FIG. 19 is a graph of the measurement data at C1 of the present invention (θ=90°).

Fig. 20 is a line graph of the measurement data at C1 of the present invention (θ=90°).

FIG. 21 is a graph of the measurement data at C2 of the present invention (θ=0°).

Fig. 22 is a line graph of the measurement data at C2 of the present invention (θ=0°).

FIG. 23 is a graph of the measurement data at C2 of the present invention (θ=30°).

Fig. 24 is a line graph of the measurement data at C2 of the present invention (θ=30°).

FIG. 25 is a graph of the measurement data at C2 of the present invention (θ=60°).

Fig. 26 is a line graph of the measurement data at C2 of the present invention (θ=60°).

FIG. 27 is a graph of the measurement data at C2 of the present invention (θ=90°).

Fig. 28 is a line graph of the measurement data at C2 of the present invention (θ=90°).

FIG. 29 is a graph of the measurement data at C3 of the present invention (θ=0°).

Fig. 30 is a line graph of the measurement data at C3 of the present invention (θ=0°).

FIG. 31 is a graph of the measurement data at C3 of the present invention (θ=30°).

Fig. 32 is a line graph of the measurement data at C3 of the present invention (θ=30°).

FIG. 33 is a graph of the measurement data at C3 of the present invention (θ=60°).

Fig. 34 is a line graph of the measurement data at C3 of the present invention (θ=60°).

Figure 35 is a graph of the measurement data at C3 of the present invention (θ=90°).

Fig. 36 is a line graph of the measurement data at C3 of the present invention (θ=90°).

Among them: 1. Centering column, 2. Semiconductor laser transmitter, 3. Special measuring tool for propeller blade thickness, 4. Three-jaw chuck, 5. Rotating arm, 6. Propeller,

31, spring, 32, spring tip shell, 33, feet, 34, spring tip, 35, lower tip, 36, U-shaped attachment, 37, spiral micrometer.

Detailed ways

As shown in FIG. 1, a propeller blade thickness measurement device includes a U-shaped attachment 36; the two ends of the U-shaped attachment 36 are respectively a fixed end and a measuring end; The outer side is provided with a spring top shell 32; the support foot 33 is a three-leg bracket, and the bottom of the three legs of the support foot 33 is located on the same horizontal plane A, and the connection line at the bottom of the three legs is an equilateral triangle. The support feet 33 are used to determine the normal direction of the point to be measured on the propeller blade.

A spring tip 34 is arranged in the spring tip housing 32, and a spring 31 is arranged between the spring tip 34 and the inner wall of the spring tip housing 32, so that the front end of the spring tip 34 can pass through the fixed end of the U-shaped attachment 36, and extend to the bottom of the legs of the legs 33 , and the spring tip housing 32 is used to carry the spring 31 and the spring tip 34 .

The spring tip 34 is provided with an annular protrusion for position limit on the side close to the support foot 33 , so that one end of the spring 31 is pressed against the annular protrusion, and the other end is pressed against the inner wall of the spring tip housing 32 .

The spring 31 is selected as a spring with low stiffness and small damping, which can realize the axial expansion and contraction function of the spring tip 34 . The axis where the spring tip 34 is located is perpendicular to the horizontal plane A where the bottom of the leg of the support foot 33 is located; the spring tip 34 is used to indicate the point to be measured on the propeller blade.

The spring tip housing 32 is threadedly connected to the fixed end of the U-shaped attachment 36 in a detachable and fixed form, and the support feet 33 are threadedly connected to the fixed end of the U-shaped attachment 36 .

A screw micrometer 37 is detachably connected to the measuring end of the U-shaped accessory 36 . Preferably, the outer wall of the mounting section of the screw micrometer 37 is threadedly connected to the measuring end of the U-shaped accessory 36 .

The front end of the screw micrometer 37 is provided with a lower tip 35; the spring tip 34 and the lower tip 35 are coaxially arranged, and the tips are oppositely arranged, and the lower tip 35 is used to determine the position of the lower surface point of the propeller blade .

The helical micrometer 37 is used to accurately measure the thickness of the point to be measured on the propeller blade. The U-shaped attachment 36 can be replaced with various models, which are used to carry other components and ensure that the spring tip 34 and the lower tip 35 are coaxial.

The height of the U-shaped attachment 36 is H, and H is preferably 30 mm, 60 mm or 90 mm. During on-site measurement, different types of U-shaped attachments can be selected according to the position of the blade to be measured.

As shown in Figure 3, the distance between points C1, C2, and C3 from the edge of the propeller blade is 25mm in Figure 3. In this case, a U-shaped attachment of the type H=30 should be used.

However, if you want to measure the thickness at a point farther from the blade edge, such as a point 50 away from the blade edge, then H=30<50 at this time, and the bottom of the U-shaped attachment will be blocked by the blade edge due to size limitations. Therefore, the U-shaped accessory of the model H=60 should be replaced at this time. The U-shaped attachment is made into a replaceable form, so that the measuring tool can adapt to different measurement positions and meet the measurement needs of different positions.

As shown in Figures 1 to 7, a measurement system includes a blade point-to-be-measured positioning device and a blade point-to-be-measured thickness detection device; the blade to-be-measured point thickness detection device is the above-mentioned propeller blade thickness measurement device; The positioning device for the blade to be measured point includes a centering column 1, a semiconductor laser transmitter 2, a three-jaw chuck 4 and a rotating arm 5, which realizes the radial and circumferential positioning of the blade to be measured point.

The three-jaw chuck 4 is provided with a propeller 6 in the middle, and the upper surface of the three-jaw chuck 4 has an indexing plate; and positioning function to realize the clamping and positioning of the 6 blades of the propeller; the second is to use the indexing plate device with it to realize the precise angular rotation of the workpiece.

The centering column 1 is arranged on the outside of the three-jaw chuck 4, and the centering column 1 includes a vertically arranged support portion and a horizontally arranged fixing portion; preferably, the fixing portion of the centering column 1 is supported with the same support The top of the part is connected vertically. The fixed part of the centering column 1 is provided with a rotating arm 5, the center of the rotating arm 5 is rotatably connected with the fixed part, and the center of the rotating arm 5 is coaxial with the blade axis of the propeller 6; the end of the rotating arm 5 A semiconductor laser transmitter 2 is provided for indicating the position of the point to be measured in real time; the semiconductor laser transmitter 2 is commonly known as a laser pen, has high light concentration, can realize the function of non-contact indication, and can indicate the position of the point to be measured in real time.

The thickness detection device for the point to be measured on the blade can measure the thickness of the point to be measured indicated by the semiconductor laser transmitter 2 . When the rotating arm 5 rotates relative to the center of the rotating arm 5, the semiconductor laser transmitter 2 can rotate in a circle of R190. The rotating arm 5 is used to carry the semiconductor laser transmitter 2 and determine the circumference of R190.

As shown in Figure 1 to Figure 7, a measurement method using the above measurement system includes the following steps:

S1. Clamp the propeller 6 on the three-jaw chuck 4 of the blade to be measured point positioning device.

S2. Rotate the rotating arm 5 so that the light spot of the semiconductor laser transmitter 2 falls on the edge of the blade of the propeller 6, and mark the laser spot, that is, the point to be measured, point C1.

S3. Rotate the three-jaw chuck 4 with an indexing plate by 16° in turn. Similarly, mark the points to be measured, C2 and C3, on the blade surface of the propeller 6.

S4. Use the thickness detection device of the point to be measured on the blade to measure the thickness values of the points to be measured, C1, C2, and C3 in turn.

The measurement of S4 specifically includes the following steps:

S41, coincide the spring top 34 with the point to be measured.

S42 , adjusting the support feet 33 to make them stably supported on the curved surface of the blades of the propeller 6 .

S43. Rotate the helical micrometer 37 to make the lower tip 35 in close contact with the lower surface of the blade, and read the reading.

S44, repeat the measurement three times, record the data, and calculate the average value as the thickness of the 6 blades of the propeller at this point.

During the measurement, it is necessary to measure the thickness values of three points C1, C2 and C3 according to the propeller design drawings. Because the propeller blade is a high-order surface, its blade thickness is not equal everywhere.

Therefore, in order to represent the information of the thickness of the propeller blade, it is necessary to take a special point at a special position, and give the thickness information at the special point. The processing method of the propeller blade is casting. After the casting is formed, the thickness of the blank at these three points is measured to check whether the casting accuracy meets the requirements.

As shown in Figure 3, the measurement method of the present invention measures the processing dimensions C1, C2, C3 (note: the thickness of the blade along the normal direction at this point), firstly determine the R190 circle; then use the blade edge as the benchmark to determine 16 The positions of the °, 32°, and 48° lines can be used to determine the points C1, C2, and C3; finally, use the special measuring tool for the thickness of the propeller blade to measure the thickness of the blade. The measuring device has a simple structure, low cost, and accurate measurement.

The design principle of the propeller blade thickness measuring device of the present invention is the original "three-point method", and the rationality of the method is proved theoretically.

1. The key to measurement: determine the normal direction of a point on the blade surface, and present the normal direction in real time in real time, which is convenient for measurement. Converting into a mathematical problem is: find the normal direction of a point on a free-form surface.

2. The idea of measurement: "replacing points with faces"

等价于其邻域三点所在平面的法线

即

2.1 As shown in Figure 8, in actual engineering, to display the normal direction of a point on the plane in real time, it is usually realized by a triangular panel with a column. Its principle, as shown in Figure 9, the normal of any point P in the plane

Equivalent to the normal of the plane where the three neighboring points are located

which is

2.2 Similarly, when the curvature of a surface is small, the normal of the plane where the three points are located in the neighborhood of the point to be measured can be used to approximate the normal of the point to be measured, that is, the "three-point method".

2.3 Prerequisites for the application of the "three-point method": the curvature of the surface is small and does not change much. In the neighborhood of the point to be measured, it can be approximately regarded as a plane.

Verify that the model meets the prerequisites for the application of the "three-point method"

1. Import the step model of a certain type of propeller blade into Creo.

2. By displaying the "Gaussian curvature" of the blade surface, determine the curvature of the surface at the point to be measured and the curvature change around the point to be measured.

3. The results are shown in Figure 10. The curvature values of the points C1, C2, and C3 to be measured are 0.0024, 0.0009, and 0.004, respectively, indicating that the points to be measured and the points in their neighborhoods have small curvatures.

The color of the neighborhood cloud map of the point to be measured is the same, indicating that the curvature of the surface does not change much.

In summary, the "three-point method" can be applied to determine the normal direction of the point to be measured.

Application of "Three Points Method" and Analysis of Experimental Data

1. In Creo, mark the points to be measured C1, C2, and C3, as shown in Figure 11.

2. Taking C1, C2, and C3 as the center, take three points A, B, and C in their neighborhood to form an equilateral triangle as shown in Figure 12.

In order to determine the optimal size of the triangular patch, the side length S of the equilateral triangle is a variable; in order to ensure the uniformity and representativeness of the three points taken, the angle θ between the height line of the equilateral triangle and the line connecting the point to be measured and the center of the blade is Variable, using Creo's measurement function to measure the thickness of the blade on the normal vector of the triangular facet, and compare it with the standard thickness. The data obtained at C1, see Figure 13 to Figure 20, and the data obtained at C2 and C3, see Figure 21 to Figure 36.

3. Analysis of experimental results:

3.1 It can be seen from Figure 14, Figure 16, Figure 18, and Figure 20 that as the side length S of the equilateral triangle increases (that is, as the area of the triangle patch increases), the measurement error increases.

Explain that the measurement results are affected by the side length S of an equilateral triangle. Therefore, in order to ensure that the measurement error is small, it is appropriate to take the smaller side length.

3.2 As can be seen from Figure 13, Figure 15, Figure 17, and Figure 19, the measurement results are also different when θ is different.

Explain that the measurement results are affected by the angle θ between the equilateral triangle height line and the line connecting the point to be measured and the center of the blade. But the error is less than 0.04mm, which can accept the measurement error of this size.

3.3 According to the measurement specification, the design tolerance of C1, C2, and C3 is -0.3~+0.8mm. In order to reduce the principle error of measurement as much as possible, when the final measuring tool is designed, the side length of the triangular surface should be smaller than 10mm, so that the measurement can be The principle error is controlled within 0.02mm.

The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited to this. The equivalent replacement or change of the inventive concept thereof shall be included within the protection scope of the present invention.

Claims (5)

1. A measurement system, comprising a blade thickness detection device to be measured; The thickness detection device of the blade to be measured point is a propeller blade thickness measurement device; The propeller blade thickness measuring device includes a U-shaped attachment (36); Two ends of the U-shaped accessory (36) are the fixed end and the measurement end respectively; The inner side of the fixed end of the U-shaped attachment (36) is provided with a support foot (33), and the outer side is provided with a spring tip housing (32); The support foot (33) is a three-leg support, the bottoms of the three support legs of the support foot (33) are located on the same horizontal plane A, and the line connecting the bottoms of the three support legs is an equilateral triangle; A spring tip (34) is arranged in the spring tip housing (32), and a spring (31) is arranged between the spring tip (34) and the inner wall of the spring tip housing (32), so that the spring tip (34) The front end can pass through the fixed end of the U-shaped attachment (36) and extend to the bottom of the outrigger of the outrigger (33); The axis where the spring tip (34) is located is perpendicular to the horizontal plane A where the bottom of the outrigger leg (33) is located; The measuring end of the U-shaped accessory (36) is detachably connected with a screw micrometer (37), and the front end of the screw micrometer (37) is provided with a lower tip (35); The spring tip (34) and the lower tip (35) are coaxially arranged, and the tips are oppositely arranged; It is characterized by: Also includes a blade to be measured point positioning device; The blade to-be-measured point positioning device includes a centering column (1), a semiconductor laser transmitter (2), a three-jaw chuck (4) and a rotating arm (5); A propeller (6) is sandwiched between the three-jaw chuck (4), and an indexing plate is provided on the upper surface of the three-jaw chuck (4); The centering column (1) is arranged on the outer side of the three-jaw chuck (4), and the centering column (1) includes a vertically arranged support portion and a horizontally arranged fixing portion; A rotating arm (5) is arranged on the fixed part of the centering column (1), the center of the rotating arm (5) is rotatably connected with the fixed part, and the center of the rotating arm (5) is coaxial with the blade axis of the propeller (6). axis; The end of the rotating arm (5) is provided with a semiconductor laser transmitter (2) for indicating the position of the point to be measured in real time; The thickness detection device of the point to be measured of the blade can measure the thickness of the point to be measured indicated by the semiconductor laser transmitter (2); The spring tip (34) is provided with an annular protrusion for position limiting on the side close to the support foot (33), so that one end of the spring (31) is pressed against the annular protrusion, and the other end is pressed against the inner wall of the spring tip housing (32); The outer wall of the mounting section of the screw micrometer (37) is threadedly connected with the measuring end of the U-shaped accessory (36). 2. measurement system according to claim 1, is characterized in that: The fixed part of the centering column (1) is vertically connected with the top end of the support part. 3. measurement system according to claim 1, is characterized in that: When the rotating arm (5) rotates relative to the center of the rotating arm (5), the semiconductor laser transmitter (2) can rotate in a circle of R190. 4. a measurement method using the measurement system described in any one of the above claims 1-3, is characterized in that comprising the following steps: S1. Clamp the propeller (6) on the three-jaw chuck (4) of the blade to-be-measured point positioning device; S2. Rotate the rotating arm (5) so that the light spot of the semiconductor laser transmitter (2) falls on the edge of the blade of the propeller (6), and mark the laser spot, that is, the point to be measured, point C1; S3. Rotate the three-jaw chuck (4) with an indexing plate by 16° in turn. Similarly, mark the points to be measured, C2 and C3, on the blade surface of the propeller (6); S4. Use the thickness detection device of the point to be measured on the blade to measure the thickness values of the points to be measured, C1, C2, and C3 in turn. 5. measuring method according to claim 4, is characterized in that: The measurement of S4 specifically includes the following steps: S41, coincide the spring tip (34) with the point to be measured; S42. Adjust the support feet (33) so that they are stably supported on the curved surface of the blades of the propeller (6); S43. Rotate the helical micrometer (37) to make the lower tip (35) in close contact with the lower surface of the blade, and read out the reading; S44. Repeat the measurement three times, record the data, and calculate the average value as the blade thickness of the propeller (6) at this point.

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