A device and method for detecting straightness of an inner wall of a cylinder

Abstract

The application discloses a kind of straightness detection device and method of cylinder inner wall, device includes including main frame, laser tracking ball, traction mechanism and laser tracker, the main frame can be placed in the inner wall of large length-diameter ratio cylinder and move along the length direction of cylinder by traction mechanism;The laser tracking ball is elastically connected with main frame, when main frame is placed in cylinder, laser tracking ball is contacted with the inner wall of cylinder;The laser tracker is used to detect the motion trail of laser tracking ball.Method is carried out using the above device.By laser tracker, the motion trail of laser tracking ball along the inner wall of cylinder is fitted, and then the straightness information on the trail can be obtained, it is easy to operate, and measurement precision is high.

Description

Technical Field

[0001] This invention relates to the field of straightness testing technology, and in particular to a device and method for testing the straightness of the inner wall of a cylinder. Background Technology

[0002] Composite material cylinders are cylindrical structures composed of two or more different materials. They are typically made of fiber-reinforced composite materials and a resin matrix, manufactured through processes such as lamination and curing. These cylinders are lightweight, high-strength, and corrosion-resistant, and have wide applications in aerospace, automotive, and shipbuilding industries.

[0003] After the composite material cylinder is removed from the molding die, the straightness of its inner wall needs to be tested. For cylinders with a length-to-diameter ratio (L / D ratio) ≥ 20, testing the straightness of the inner wall is quite difficult. Firstly, the cylinder is long, exceeding 10m, while the inner diameter is small, less than 500mm. Traditional testing methods (such as the ruler method, alignment method, straightness method, and verticality method) are difficult to implement and unsuitable. Other specialized testing methods, such as the steel pipe inner wall straightness measuring device disclosed in patent document CN115183659A, which uses a slide rail on the inner wall of the cylinder and a dial indicator sliding along the rail to measure the straightness, are too complex to operate, have low measurement accuracy, and are difficult to read data, thus failing to meet the accuracy requirements for testing the straightness of the inner wall of cylinders with large L / D ratios. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a device and method for detecting the straightness of the inner wall of a cylinder, which is simple to operate and has high detection accuracy.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A device for detecting the straightness of the inner wall of a cylinder includes a main frame, a laser tracking ball, a traction mechanism, and a laser tracker for detecting the motion trajectory of the laser tracking ball. The main frame can be placed on the inner wall of the cylinder and moved along the length of the cylinder by the traction mechanism. The laser tracking ball is elastically connected to the main frame so that the laser tracking ball always remains in contact with the inner wall of the cylinder when the main frame moves.

[0007] As a further improvement to the above solution:

[0008] The main frame includes a column and rollers. At least two sets of rollers are provided. Each roller and the laser tracking ball are distributed at intervals along the circumference of the column, so that when the main frame is placed inside the cylinder, each roller and the laser tracking ball are in contact with the inner wall of the cylinder and the central axis of the column coincides with the central axis of the cylinder.

[0009] The main frame further comprises an adjusting assembly, a first movable rod and a second movable rod, the column body comprises a first end and a second end; one end of the first movable rod is hingedly connected to the adjusting assembly, and the other end is provided with a roller or a laser tracking ball; one end of the second movable rod is hingedly connected to the second end, and the other end is provided with a roller or a laser tracking ball; the number of the first movable rods and the second movable rods is the same and at least three groups are provided; the first movable rods and the second movable rods are hingedly connected to each other, and the hinged angle of the first movable rods and the second movable rods changes under the action of the adjusting assembly, so that the radial distance of the two rollers or laser tracking balls relative to the column body is adjusted.

[0010] The first movable rods and the second movable rods are each provided in three groups, and each group of the first movable rods or the second movable rods is uniformly distributed along the circumferential direction of the column body.

[0011] A pull ring connected with the traction mechanism is arranged on the second end at the central axis of the column body, and the traction mechanism comprises a traction rope for connecting with the pull ring.

[0012] The laser tracking ball is provided with one and is arranged on the end of one of the second movable rods.

[0013] The main frame further comprises an elastic sleeve, which is elastically connected to the end of the first movable rod and the second movable rod towards the inner wall of the column body and can elastically move along the length direction of the first movable rod or the second movable rod, and the roller and the laser tracking ball are arranged on the elastic sleeve.

[0014] The adjusting assembly comprises an adjusting ring and a limiting ring, the adjusting ring is slidably connected with the column body, the column body is provided with a thread on the annular surface, the limiting ring is threadedly connected with the column body, and the limiting ring is provided with two and located on both sides of the length direction of the adjusting ring.

[0015] A method for detecting the straightness of the inner wall of a column body is performed by using the straightness detection device of the inner wall of the column body, and comprises the following steps:

[0016] S1, a column body whose straightness is to be detected is fixedly arranged, the main frame is placed in one end of the column body, the laser tracking ball is in contact with the inner wall of the column body, and the traction rope of the traction mechanism is fixedly connected with the main frame and extends out from the other end of the column body.

[0017] S2, the traction mechanism is started to make the traction rope approach a taut state, the relative position of the traction mechanism and the column body is corrected, and the traction rope is coaxial with the column body.

[0018] S3, the traction mechanism is started to transport and drag the traction rope, until the main frame passes through the column body, and the running track of the laser tracking ball is recorded by the laser tracking instrument.

[0019] S4, a plurality of measuring points are arranged along the measured straight line direction at intervals, the displacement distance of the laser tracking ball along each measuring point in the direction perpendicular to the measured straight line direction is recorded by the laser tracker, and all the measured values are fitted into a curve, and the maximum offset value in the curve is the straightness of the cylinder in the measured straight line direction.

[0020] The length of the cylinder is greater than 10m, and the length-diameter ratio of the cylinder is greater than or equal to 20.

[0021] In step S3, the displacement distance of the laser tracking ball perpendicular to the measured straight line direction is Dz, a plurality of measuring points are arranged along the measured straight line direction at intervals, the Dz values of each measuring point are recorded by the laser tracker, and all the measured values are fitted into a curve, and the maximum offset value in the curve is the straightness of the cylinder in the measured straight line direction.

[0022] Compared with the prior art, the advantages of the present application are that:

[0023] The present application provides a straightness detection device and method for the inner wall of a cylinder, which moves along the length direction of the cylinder by setting a main frame, and then sets a laser tracking ball on the main frame which can contact the inner wall of the cylinder, and then fits the movement track of the laser tracking ball sliding along the inner wall of the cylinder by a laser tracker, and then obtains the straightness information on the track. The running track fitting speed is fast, the position information of all points on the track can be obtained, the data reading is convenient, and the measurement accuracy is high. When in use, the main frame is placed in the cylinder to ensure that the laser tracking ball contacts the inner wall of the cylinder, and then the main frame is pulled by the traction device, which is convenient to operate.

[0024] The present application adjusts the radial distance between the roller and the laser tracking ball and the column within a certain range by the adjusting assembly, so that the device can be applied to cylinders with different diameters for straightness measurement, and has good adaptability. DETAILED DESCRIPTION

[0025] Fig. 1 It is the first perspective view of the main frame in the embodiment.

[0026] Fig. 2 It is the second perspective view of the main frame in the embodiment.

[0027] Fig. 3 It is a structure schematic view of the main frame installed in the inside of the cylinder in the embodiment.

[0028] Fig. 4 It is a structure schematic view of the straightness detection device for the inner wall of the cylinder in the embodiment.

[0029] The various reference numerals in the drawings represent:

[0030] 1. Laser tracking ball; 2. Traction mechanism; 3. Laser tracker; 4. Cylinder; 51. Adjusting ring; 52. First movable rod; 53. Second movable rod; 54. Elastic sleeve; 55. Limiting ring; 6. Column; 61. Pull ring; 62. First end; 63. Second end; 7. Roller. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] Device Example 1:

[0033] Figs. 1 to 4 This invention illustrates an embodiment of a device for detecting the straightness of the inner wall of a large aspect ratio cylindrical body 4. The device includes a main frame, a laser tracking ball 1, a traction mechanism 2, and a laser tracker 3 for detecting the motion trajectory of the laser tracking ball 1. The main frame can be placed on the inner wall of the cylindrical body 4 and moved along the length of the cylindrical body 4 by the traction mechanism 2. The laser tracking ball 1 is elastically connected to the main frame, ensuring that the laser tracking ball 1 remains in contact with the inner wall of the cylindrical body 4 when the main frame moves. In this structure, by setting the main frame to move along its length within the cylindrical body 4, and by placing the laser tracking ball 1 on the main frame to contact the inner wall of the cylindrical body 4, the laser tracker 3 can fit the motion trajectory of the laser tracking ball 1 sliding along the inner wall of the cylindrical body 4, thereby obtaining the straightness information on this trajectory. This device offers fast trajectory fitting speed, can obtain the position information of all points on a trajectory, facilitates data reading, and has high measurement accuracy. In use, the main frame is placed inside the cylindrical body 4 to ensure contact between the laser tracking ball 1 and the inner wall of the cylindrical body 4, and then the main frame is tractioned by the traction device, making operation convenient.

[0034] In this embodiment, the main frame includes a column 6 and rollers 7. At least two sets of rollers 7 are provided, with each roller 7 and the laser tracking ball 1 distributed at intervals along the circumference of the column 6. This ensures that when the main frame is placed inside the cylinder 4, each roller 7 and the laser tracking ball 1 are in contact with the inner wall of the cylinder 4, and the central axis of the column 6 coincides with the central axis of the cylinder 4. In this structure, the rollers 7 facilitate the sliding movement of the main frame within the cylinder 4. By providing at least two sets of rollers 7 and the laser tracking ball 1 distributed at intervals along the circumference of the column 6, the principle of three points defining a circle is adopted to ensure that the rollers 7 and the laser tracking ball 1 on the main frame are always in simultaneous contact with the inner wall of the cylinder 4 during sliding, further improving the accuracy and reliability of the measurement results.

[0035] In the embodiment, the main frame further comprises an adjusting assembly, first movable rods 52 and second movable rods 53, the column 6 comprises a first end 62 and a second end 63, one end of each first movable rod 52 is hinged to the adjusting assembly, and the other end is provided with a roller 7 or a laser tracking ball 1, one end of each second movable rod 53 is hinged to the second end 63, and the other end is provided with a roller 7 or a laser tracking ball 1, the number of the first movable rods 52 and the second movable rods 53 is the same and at least three groups are provided, the first movable rods 52 and the second movable rods 53 are hinged to each other, and the adjusting assembly changes the hinged angle of the first movable rods 52 and the second movable rods 53 to adjust the radial distance between the rollers 7 or the laser tracking balls 1 and the column 6. Specifically, the adjusting assembly comprises an adjusting ring 51 and a limiting ring 55, the adjusting ring 51 is slidably sleeved with the column 6, the annular surface of the column 6 is provided with threads, the limiting ring 55 is threadedly connected with the column 6, and the limiting ring 55 is provided with two and located at both sides of the length direction of the adjusting ring 51. In the structure, the radial distance between the rollers 7 and the laser tracking balls 1 and the column 6 can be adjusted within a certain range by adjusting the adjusting ring 51, so that the device can be applicable to different diameter sizes of the cylinder 4 for straightness measurement, and the applicability of the device is improved. The diameter of the circumscribed circle of the rollers 7 and the laser tracking balls 1 is increased by moving the adjusting ring 51 towards the second end 63, and the diameter of the circumscribed circle of the rollers 7 and the laser tracking balls 1 is reduced by moving the adjusting ring 51 towards the first end 62, which is convenient to operate.

[0036] In the embodiment, the first movable rods 52 and the second movable rods 53 are provided with three groups, and each group of first movable rods 52 or second movable rods 53 is uniformly distributed along the annular direction of the column 6. A pull ring 61 for connecting with the traction mechanism 2 is arranged on the second end 63 at the central axis of the column 6, and the traction mechanism 2 comprises a traction rope for connecting with the pull ring 61. The laser tracking ball 1 is provided with one and arranged on one end of the second movable rod 53. Through the structure, the stability of the main frame structure is ensured, the overall structure is simplified, and the straightness measurement operation is facilitated. By arranging the laser tracking ball 1 on the second movable rod 53, the sliding resistance is reduced, and the accuracy of the measurement structure is ensured. The device can also be provided with multiple laser tracking balls 1, which facilitates multiple measurements of multiple positions at the same time, and the straightness of the cylinder 4 can be more comprehensively understood.

[0037] In this embodiment, the adjusting assembly further comprises an elastic sleeve 54, which is elastically connected to the end of the first movable rod 52 and the second movable rod 53 towards the inner wall of the cylinder body 4, and the roller 7 and the laser tracking ball 1 are arranged on the elastic sleeve 54. In this structure, the elastic sleeve 54 is elastically connected to the first movable rod 52 or the second movable rod 53, and the elastic sleeve 54 is slidingly connected to the end of the first movable rod 52 or the second movable rod 53. A spring is arranged between the elastic sleeve 54 and the first movable rod 52 or the second movable rod 53, thereby forming an elastic connection, so that the roller 7 and the laser tracking ball 1 can be elastically adjusted within a certain range according to the diameter change of the inner wall of the cylinder body 4, ensuring that the roller 7 and the laser tracking ball 1 are always in contact with the inner wall of the cylinder body 4 during movement, thereby improving the accuracy of the straightness testing structure. On the other hand, it can further improve the adaptability of the main frame to the cylinder body 4 with different diameter sizes.

[0038] Method embodiment:

[0039] A straightness detection method for the inner wall of a large-length-diameter-ratio cylinder body 4 is carried out by using the straightness detection device for the inner wall of a large-length-diameter-ratio cylinder body 4 in the device embodiment, comprising the following steps:

[0040] S1, fix the cylinder body 4 to be detected for straightness, place the main frame in one end of the cylinder body 4, so that the laser tracking ball 1 is in contact with the inner wall of the cylinder body 4, and the traction rope of the traction mechanism 2 is fixedly connected with the main frame and extends out from the other end of the cylinder body 4.

[0041] S2, start the traction mechanism 2 to make the traction rope approach a taut state, correct the relative position of the traction mechanism 2 and the cylinder body 4, and make the traction rope coaxial with the cylinder body 4.

[0042] S3, start the traction mechanism 2 to transport the traction rope until the main frame passes through the cylinder body 4, and record the running track of the laser tracking ball 1 by the laser tracker 3.

[0043] S4, set a plurality of measurement points along the measured straight line direction, record the value of the displacement distance of the laser tracking ball 1 perpendicular to the measured straight line direction at each measurement point by the laser tracker 3, and fit all the measurement values into a curve, and the maximum offset value in the curve is the straightness of the cylinder body 4 in the measured straight line direction.

[0044] The length of the cylinder body is greater than 10m, and the length-diameter ratio of the cylinder body is greater than or equal to 20.

[0045] Although the present application has been disclosed with reference to the preferred embodiments, it is not intended to limit the present application. Any person skilled in the art, without departing from the technical scope of the present application, can make many possible changes and modifications to the disclosed technical content of the present application, or modify equivalent embodiments of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments without departing from the technical content of the present application, according to the technical essence of the present application, shall fall within the scope of protection of the present application.

Claims

1. A device for detecting the straightness of the inner wall of a cylinder, characterized in that: The system includes a main frame, a laser tracking ball (1), a traction mechanism (2), and a laser tracker (3) for detecting the motion trajectory of the laser tracking ball (1). The main frame can be placed on the inner wall of the cylinder (4) and moved along the length of the cylinder (4) by the traction mechanism (2). The laser tracking ball (1) is elastically connected to the main frame so that when the main frame moves, the laser tracking ball (1) always remains in contact with the inner wall of the cylinder (4). The main frame includes a column (6) and rollers (7). The rollers (7) are provided in at least two sets. Each roller (7) and the laser tracking ball (1) are distributed at intervals along the circumference of the column (6), so that when the main frame is placed inside the cylinder (4), each roller (7) and the laser tracking ball (1) are in contact with the inner wall of the cylinder (4) and the central axis of the column (6) coincides with the central axis of the cylinder (4). The main frame also includes an adjustment assembly, a first movable rod (52) and a second movable rod (53), and the column (6) includes a first end (62) and a second end (63); one end of the first movable rod (52) is hinged to the adjustment assembly, and the other end is provided with a roller (7) or a laser tracking ball (1); one end of the second movable rod (53) is hinged to the second end (63), and the other end is provided with a roller (7) or a laser tracking ball (1); the number of the first movable rod (52) and the second movable rod (53) is the same and there are at least three sets; the first movable rod (52) and the second movable rod (53) are hinged to each other, and the hinge angle of the first movable rod (52) and the second movable rod (53) changes under the action of the adjustment assembly, so as to adjust the radial distance of the roller (7) or the laser tracking ball (1) relative to the column (6); The main frame also includes an elastic sleeve (54), which is elastically connected to the ends of the first movable rod (52) and the second movable rod (53) facing the inner wall of the cylinder (4) and can move elastically along the length of the first movable rod (52) or the second movable rod (53). The roller (7) and the laser tracking ball (1) are arranged on the elastic sleeve (54). The adjustment assembly includes an adjustment ring (51) and a limiting ring (55). The adjustment ring (51) is slidably sleeved with the column (6). The column (6) has a thread on its ring surface. The limiting ring (55) is threadedly connected to the column (6). There are two limiting rings (55) and they are located on both sides of the length direction of the adjustment ring (51).

2. The device for detecting the straightness of the inner wall of a cylinder according to claim 1, characterized in that: The first movable rod (52) and the second movable rod (53) are each provided in three sets, and the first movable rod (52) or the second movable rod (53) in each set are evenly distributed along the circumferential interval of the column (6).

3. The device for detecting the straightness of the inner wall of a cylinder according to claim 2, characterized in that: The second end (63) is provided with a pull ring (61) connected to the traction mechanism (2) at the central axis of the column (6). The traction mechanism (2) includes a traction rope for connecting to the pull ring (61).

4. The straightness detection device for the inner wall of the cylinder according to claim 3, characterized in that: The laser tracking ball (1) is provided and is located at the end of a second movable rod (53).

5. A method for detecting the straightness of the inner wall of a cylinder, characterized in that: The straightness detection device for the inner wall of the cylinder as described in any one of claims 1 to 4 is used, and the process includes the following steps: S1. Fix the cylinder (4) whose straightness is to be tested, place the main frame inside one end of the cylinder (4), make the laser tracking ball (1) contact the inner wall of the cylinder (4), fix the traction rope of the traction mechanism (2) to the main frame and extend it from the other end of the cylinder (4); S2. Start the traction mechanism (2) to bring the traction rope close to the taut state, and correct the relative position of the traction mechanism (2) and the cylinder (4) to make the traction rope and the cylinder (4) coaxial. S3. Start the traction mechanism (2) to transport and drag the traction rope until the main frame passes through the cylinder (4), and record the running trajectory of the laser tracking ball (1) through the laser tracker (3); S4. Set several measurement points at intervals along the direction of the line to be measured. Record the displacement distance of the laser tracking ball (1) at each measurement point perpendicular to the direction of the line to be measured by the laser tracker (3). Fit all the measurement values ​​into a curve. The maximum offset value in the curve is the straightness of the cylinder (4) in the direction of the line to be measured.

6. The method for detecting the straightness of the inner wall of the cylinder according to claim 5, characterized in that: The length of the cylinder is greater than 10m, and the length-to-diameter ratio of the cylinder is ≥20.

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