Method for detecting eccentricity of eccentric hole of thin-walled cylinder

Abstract

The present application relates to product size detection technical field, disclose a kind of eccentricity detection method of eccentric hole of thin-walled cylinder, thin-walled cylinder cylinder wall has at least one eccentric hole, detection device includes locating block, supporting block and the locating pin matched with eccentric hole size;Locating block is equipped with with the outer ring matched with thin-walled cylinder inner hole, thin-walled cylinder is positioned for detection by being set on outer ring;Supporting block includes bottom plate and the supporting plate perpendicular to bottom plate, and supporting plate is equipped with detection datum plane, and detection datum plane is coplanar with the central axis of thin-walled cylinder;After locating pin is inserted eccentric hole, adjust the position of thin-walled cylinder to locating pin axis and detection datum plane parallel;The distance between locating pin axis and detection datum plane is obtained eccentricity by detection, i.e.eccentricity.The part is positioned by locating plate and outer ring, and the part is pressed by supplementary pressing plate, to ensure that the part is stably positioned;Design supporting block and locating pin cooperation, eccentricity is converted into the distance of detection datum plane to locating pin axis, both ensure detection accuracy, and simplify detection step.

Description

Technical Field

[0001] This invention relates to the field of product size inspection technology, specifically to a method for detecting the eccentricity of an eccentric hole in a thin-walled cylinder. Background Technology

[0002] like Figure 1 and Figure 2 The thin-walled cylinder shown has an eccentric hole on its surface. The eccentricity of the eccentric hole generally has a large tolerance, but it is a dimension that must be inspected in aircraft manufacturing. However, thin walls are prone to deformation, the hole is short in length, and there is no complete circular cross-section. Therefore, it is impossible to obtain a complete circumference point on a cross-section using coordinate measuring machine, and the measurement efficiency is low.

[0003] Patent CN2019105433505 discloses an eccentricity measuring device for eccentric holes, which is mainly used for detecting the eccentricity of through eccentric holes parallel to the axis on shaft parts. The technical solution adopted is: a reference shaft is installed in the eccentric hole of the part, the reference shaft is rotated by a center, the rotating reference shaft is sensed and detected by a displacement sensor and the signal is fed back to the data processor to finally obtain the eccentricity.

[0004] Although this measuring device also detects the eccentricity of eccentric holes, the position of the eccentric hole it faces is different. The hole measured in this patent is parallel to the axis of the part, and cannot be applied to eccentric holes that are perpendicular to the axis of the part in space. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a method for detecting the eccentricity of the eccentric hole of a thin-walled cylinder that can be used to inspect batch products. The detection device can quickly and effectively reflect whether the eccentricity is qualified or not.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A method for detecting the eccentricity of an eccentric hole in a thin-walled cylinder is disclosed. The thin-walled cylinder has at least one eccentric hole on its wall. A detection device is used to detect the eccentricity. The detection device includes a positioning block, a support block, and a positioning pin adapted to the size of the eccentric hole. The positioning block has an outer ring adapted to the inner hole of the thin-walled cylinder, and the thin-walled cylinder is fitted onto the outer ring for detection and positioning. The support block includes a base plate and a support plate perpendicular to the base plate. A detection reference surface is provided on the support plate, and the detection reference surface is coplanar with the central axis of the thin-walled cylinder. After the positioning pin is inserted into the eccentric hole, the position of the thin-walled cylinder is adjusted until the axis of the positioning pin is parallel to the detection reference surface. The eccentricity is obtained by detecting the distance between the axis of the positioning pin and the detection reference surface.

[0008] Furthermore, the multiple locating pins are grouped according to the tolerance of the eccentric hole. During the inspection, the larger diameter locating pin is preferred to be inserted into the eccentric hole until a locating pin of the appropriate size is selected.

[0009] Furthermore, after the locating pin is inserted into the eccentric hole, it is necessary to confirm that the axis of the locating pin is parallel to the lower end face of the thin-walled cylinder before conducting the test.

[0010] Furthermore, the positioning block also includes a positioning plate disposed below the outer ring, with the lower end face of the thin-walled cylinder contacting and positioning the positioning plate.

[0011] Furthermore, the detection device also includes a go / no-go gauge, which is used to insert between the detection reference surface and the locating pin to detect the eccentricity. The go / no-go gauge includes a go end and a no-go end.

[0012] Furthermore, the end of the positioning pin inserted into the eccentric hole is a conical end.

[0013] Furthermore, the detection device also includes a pressure plate, which is arranged parallel to the positioning plate, and the lower surface of the pressure plate contacts the thin-walled cylinder to press and fix the thin-walled cylinder.

[0014] Furthermore, the pressure plate and the positioning block are connected by clamping screws.

[0015] Furthermore, the detection device also includes a base, and the positioning block and the support block are all mounted on the base.

[0016] Furthermore, both the positioning block and the support block are connected to the base with screws.

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

[0018] This testing method uses the positioning plate and outer ring on the positioning block to position the part, and at the same time, the pressure plate presses down on the part to ensure stable positioning of the part; the design of the support block and positioning pin cooperates to convert the eccentricity into the distance from the detection reference surface on the support plate to the axis of the positioning pin, which can not only ensure the accuracy of the eccentricity detection, but also simplify the eccentricity detection steps and reduce the detection cost.

[0019] Introducing go / no-go gauges to perform conformity checks on eccentricity is particularly suitable for the inspection of batch parts. It offers high inspection efficiency, simple operation, and low requirements for the professional level of the inspectors. Attached Figure Description

[0020] Figure 1 This is a top view of the thin-walled cylinder described in Example 1;

[0021] Figure 2 This is a cross-sectional view of the thin-walled cylinder described in Example 1;

[0022] Figure 3 This is a three-dimensional structural diagram of the thin-walled cylinder eccentricity detection device described in Example 1;

[0023] Figure 4 for Figure 1 Front view of the detection device;

[0024] Figure 5 for Figure 1 Schematic diagram of the structure of the center go / no go gauge;

[0025] Figure 6 This is a schematic diagram of the grouping of positioning pins in the detection method described in Example 3.

[0026] Among them, 1-thin-walled cylinder; 11-eccentric hole; 12-boss; 2-positioning block; 21-outer ring; 22-positioning plate; 23-connecting block; 3-support block; 31-base plate; 32-support plate; 321-inspection reference surface; 4-positioning pin; 5-base; 6-screw; 7-pressure plate; 8-clamping screw; 9-go / no-go gauge; 91-go end; 92-no-go end. Detailed Implementation

[0027] The present invention will be further described below with reference to specific embodiments. The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures, and should not be construed as limiting the present patent. In order to better illustrate the embodiments of the present invention, some parts in the drawings may be omitted, enlarged or reduced, and do not represent the actual product size. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0028] Example 1

[0029] A method for detecting the eccentricity of an eccentric hole in a thin-walled cylinder, employing methods such as... Figure 3 The thin-walled cylinder eccentricity detection device shown is used in this embodiment. The thin-walled cylinder is a component on an engine. The structure of the thin-walled cylinder 1 is as follows: Figure 1 and Figure 2 As shown, two eccentric holes 11 are opened on its cylindrical surface. The detection device includes a positioning block 2, a support block 3, and a positioning pin 4 that matches the size of the eccentric hole. The support block 3 is configured one-to-one with the eccentric hole 11, and multiple positioning pins 4 can be configured according to the tolerance size of the eccentric hole.

[0030] like Figure 3 and Figure 4 As shown, the positioning block 2 is provided with an outer ring 21 that is adapted to the inner hole of the thin-walled cylinder. The outer ring 21 plays a centering role for the thin-walled cylinder. The thin-walled cylinder 1 is fitted on the outer ring 21 for detection and positioning. The positioning block 2 also includes a positioning plate 22 set below the outer ring. The lower end face of the thin-walled cylinder 1 contacts the positioning plate 22 for positioning. The outer ring 21 and the positioning plate 22 are generally integrally formed to ensure perpendicularity, so as to accurately position the thin-walled cylinder 1 and improve the detection accuracy of the eccentricity.

[0031] The support block 3 includes a base plate 31 and a support plate 32 perpendicular to the base plate. The support plate 32 and the base plate 31 are generally integrally formed. The support plate 32 has a detection reference surface 321 machined on it. When the support block 3 is placed for detection, the detection reference surface 321 is made coplanar with the central axis of the thin-walled cylinder 1. After the two positioning pins 4 are inserted into their respective eccentric holes 11, the position of the thin-walled cylinder 1 is adjusted (by rotating it appropriately along the outer ring of the positioning block) until the axis of the positioning pin 4 is parallel to the detection reference surface 321.

[0032] To further improve detection accuracy and ensure the integrity of the detection device, the device also includes a base 5, and the positioning block 2 is mounted on the base 5 by screws 6. A threaded hole can be made at the contact surface between the positioning block 2 and the base 5, and a through threaded hole is made on the base. The screws 6 extend from the bottom of the base 5 into the threaded hole on the positioning block 2, thus stably connecting the positioning block 2 and the base 5.

[0033] To avoid having to recalibrate the position of the support block 3 every time it is tested, it can usually be fixed directly to the base 5 after the position of the support block 3 is determined. Specifically, connecting screws can be installed on the base plate 31 of the support block to stably connect the support block 3 to the base 5.

[0034] The detection device also includes a pressure plate 7 that applies downward pressure to the thin-walled cylinder. The pressure plate 7 is arranged in parallel with the positioning plate 22. For the thin-walled cylinder with a boss 12 on the inner wall of the cylinder in this embodiment, the pressure plate 7 can be designed to match the inner hole size of the boss 12 of the thin-walled cylinder. After the pressure plate 7 enters the inner hole of the thin-walled cylinder, its lower surface contacts the boss 12 of the thin-walled cylinder. By applying downward pressure to the pressure plate 7, the pressure plate 7 can press and fix the thin-walled cylinder 1.

[0035] In this embodiment, to avoid introducing additional pressure-applying components to press down the pressure plate, the pressure plate 7 and the positioning block 2 can be connected by a clamping screw 8. The height of the outer ring of the positioning block can be designed to be close to or in contact with the pressure plate, or a connecting block 23 can be added above the outer ring, so that the connecting block is close to or in contact with the pressure plate. The top surface of the connecting block 23 has an opening for the clamping screw to be screwed in. Using the clamping screw 8 can ensure that the pressure-applying components apply stable and uniform pressure to the pressure plate 7, and that the pressure-applying components will not move around randomly or be lost.

[0036] The locating pin 4 inserted into the eccentric hole is designed and manufactured according to the dimensional tolerance of the eccentric hole. The end of the locating pin 4 that is inserted into the eccentric hole 11 is designed as a conical end, which is used to eliminate the gap between the locating pin and the eccentric hole. The other end of the locating pin is designed as a cylindrical end, and the size is strictly controlled. The cylindrical end is used as a measurement reference.

[0037] As described above, after all components are installed in the testing device, the distance between the testing reference surface 321 on the support block 3 and the axis of the cylindrical end of the locating pin 4 is the distance from the eccentric hole to the center of the thin-walled cylinder to be measured, which is also the eccentricity to be measured. To simplify the testing process and steps, this embodiment introduces a go / no-go gauge 9 for quick testing, such as... Figure 5 As shown, the go / no-go gauge includes a go end 91 and a no-go end 92. The dimensions of the go / no-go gauge are designed based on the distance between the detection reference surface and the cylindrical surface of the locating pin. Specifically, the gauge design calculation is performed according to GB1957 Smooth Limit Gauges to obtain the specific manufacturing dimensions of the go / no-go gauge. The go / no-go gauge 91 is used to insert between the detection reference surface 321 and the locating pin 4 for eccentricity detection. When the go end 91 of the go / no-go gauge can be inserted between the detection reference surface and the locating pin, but its no-go end 92 cannot be inserted, the eccentricity is judged to be qualified; when the go end 91 of the go / no-go gauge can be inserted between the detection reference surface and the locating pin, and the no-go end 92 can also be inserted, the eccentricity is judged to be unqualified.

[0038] This embodiment uses go and no-go gauges to determine whether the eccentricity of the eccentric hole in the thin-walled cylinder meets the requirements. There is no need to measure the specific size of the eccentricity before giving a result on whether the thin-walled cylinder is qualified or not. The eccentricity can be quickly determined by inserting the go and no-go gauges twice. The operation is simple, the detection is fast, and the accuracy of the detection can be effectively guaranteed.

[0039] Example 2

[0040] A method for detecting the eccentricity of an eccentric hole in a thin-walled cylinder, employing methods such as... Figure 3 The thin-walled cylinder eccentricity detection device shown is used in this embodiment. The thin-walled cylinder is a component on an engine. The structure of the thin-walled cylinder 1 is as follows: Figure 1 and Figure 2 As shown, two eccentric holes are formed on the cylindrical surface. The detection device includes a positioning block, a support block, and a positioning pin that matches the size of the eccentric hole. The support block and the positioning pin are configured one-to-one with the eccentric hole.

[0041] like Figure 3 and Figure 4 As shown, the positioning block has an outer ring that fits the inner hole of the thin-walled cylinder. The outer ring plays a centering role for the thin-walled cylinder. The thin-walled cylinder is fitted onto the outer ring for detection and positioning. The positioning block also includes a positioning plate set below the outer ring. The lower end face of the thin-walled cylinder contacts the positioning plate for positioning. The outer ring and the positioning plate are generally integrally formed to ensure perpendicularity, so as to accurately position the thin-walled cylinder and improve the detection accuracy of the eccentricity.

[0042] The support block includes a base plate and a support plate perpendicular to the base plate. The support plate and the base plate are generally integrally formed. A detection reference surface is machined on the support plate. When the support block is placed for detection, the detection reference surface is ensured to be coplanar with the central axis of the thin-walled cylinder. After the two positioning pins are inserted into their respective eccentric holes, the position of the thin-walled cylinder is adjusted (by rotating it appropriately along the outer ring of the positioning block) until the axis of the positioning pin is parallel to the detection reference surface.

[0043] To further improve detection accuracy while ensuring the integrity of the detection device, the device also includes a base, on which the positioning block is mounted with screws. A threaded hole can be drilled at the contact surface between the positioning block and the base, and a through threaded hole is formed on the base. Screws extend from the bottom of the base into the threaded hole on the positioning block, securing the positioning block and the base together stably.

[0044] To avoid having to recalibrate the position of the support block every time during testing, it can usually be fixed directly to the base after the position of the support block is determined. Specifically, connecting screws can be installed on the base plate of the support block to stably connect the support block to the base.

[0045] The detection device also includes a pressure plate that applies downward pressure to the thin-walled cylinder. The pressure plate is arranged in parallel with the positioning plate. For the thin-walled cylinder with a boss on the inner wall in this embodiment, the pressure plate can be designed to match the inner hole size of the boss on the thin-walled cylinder. After the pressure plate enters the inner hole of the thin-walled cylinder, its lower surface contacts the boss on the thin-walled cylinder. By applying downward pressure to the pressure plate, the pressure plate can press and fix the thin-walled cylinder.

[0046] In this embodiment, to avoid introducing additional pressure-applying components to press down the pressure plate, the pressure plate and the positioning block can be connected by clamping screws. The height of the outer ring of the positioning block is generally designed to be close to or in contact with the pressure plate, and the top surface of the outer ring has an opening for the clamping screw to be screwed in. Using clamping screws ensures that the pressure-applying components apply stable and uniform pressure to the pressure plate, and also prevents the pressure-applying components from moving around arbitrarily or being lost.

[0047] The locating pin inserted into the eccentric hole is designed and manufactured according to the dimensional tolerance of the eccentric hole. The end of the locating pin that inserts into the eccentric hole is designed as a conical end, which is used to eliminate the gap between the locating pin and the eccentric hole. The other end of the locating pin is designed as a cylindrical end, and the dimensions are strictly controlled. The cylindrical end is used as a measurement reference.

[0048] As described above, after all components are installed, the distance between the detection reference surface on the support block and the axis of the cylindrical end of the locating pin is the distance from the eccentric hole to the center of the thin-walled cylinder to be measured, which is also the eccentricity to be measured.

[0049] The difference between this embodiment and embodiment 1 is that: instead of using a go / no-go gauge to detect the eccentricity, a depth gauge or other measuring tool is used to measure and calculate the eccentricity. For example, when using a depth gauge, the end of the depth gauge is placed against the detection reference surface, and with the assistance of other tools, the distance from the cylindrical surface of the locating pin to the detection reference surface can be accurately measured. Then, the radius of the cylindrical surface of the locating pin is added to or subtracted from this distance to obtain the specific value of the eccentricity.

[0050] Compared to Example 1, this embodiment can yield a specific dimensional value for the eccentricity, but the measurement process is complex and requires numerous measuring tools, making it cumbersome for one person to operate. Furthermore, after measuring the dimensions using a gauge, calculations are still needed to determine the required eccentricity value. This embodiment cannot be used for rapid inspection of batches of thin-walled cylinders.

[0051] Example 3

[0052] This embodiment serves as a supplement to the detection method in Embodiment 1. Because the eccentric hole has tolerances, each eccentric hole generally needs to be designed with multiple locating pins to cope with the detection of different thin-walled cylinders.

[0053] Multiple locating pins need to be grouped according to the eccentric hole tolerance. For example, in this embodiment, the eccentric hole of the thin-walled cylinder is Φ5.8 (0, +0.048). The grouping of the locating pins is as follows: Figure 6 As shown, the cone end dimensions are divided into three groups from small to large. When inserting the pin into the eccentric hole for testing, the larger diameter locating pin is preferred until a locating pin of the appropriate size is selected.

[0054] The specific steps are as follows:

[0055] S1. Unscrew the clamping nut, remove the pressure plate, and place the thin-walled cylinder to the bottom until its lower section contacts the positioning plate. At this time, the thin-walled cylinder is fitted onto the outer ring of the positioning block. The upper surface of the positioning plate of the positioning block is defined as the A datum surface, and the surface of the outer ring of the positioning block is defined as the B datum surface. The installation requirement of the thin-walled cylinder is to mate it with the A datum surface and the B datum surface of the positioning block respectively.

[0056] S2. Insert the locating pins according to the position of the eccentric hole: When selecting locating pins, first select the large-diameter locating pin. If the locating pin cannot be inserted into the eccentric hole, then select the next group, and so on, until a suitable locating pin is selected and inserted into the eccentric hole.

[0057] S3. Rotate the thin-walled cylinder against the positioning block positioning plate A reference surface around the outer ring of the positioning block until the thin-walled cylinder is rotated to a suitable position where the positioning pin on it can cooperate with the support block to detect the eccentricity. Tighten the clamping nut to make the pressure plate press the thin-walled cylinder.

[0058] S4. Use a go / no-go gauge to measure the distance between the locating pin and the reference surface of the support block. If the go end can pass through but the no-go end cannot, the eccentricity of the eccentric hole is qualified. If both the go and no-go ends can pass through, the eccentricity of the eccentric hole is unqualified.

[0059] It should be noted that during the measurement process using the go / no-go gauge, the position between the locating pin and the support block detection reference surface can be adjusted by rotating the thin-walled cylinder appropriately, but it must be ensured that the thin-walled cylinder and the A reference surface are always in contact when using the go / no-go gauge.

[0060] In addition, after the locating pin is inserted into the eccentric hole, it is necessary to confirm that the axis of the locating pin is parallel to the lower end face of the thin-walled cylinder before testing. This can be confirmed by using a dial indicator, that is, adjusting the center axis of the locating pin to be parallel to the A reference plane with a dial indicator, and then tightening the clamping screw to clamp the part.

[0061] Obviously, the above embodiments are merely examples to clearly illustrate the technical solutions of the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for detecting the eccentricity of an eccentric hole in a thin-walled cylinder, wherein the thin-walled cylinder has at least one eccentric hole on its wall, characterized in that... The eccentricity is detected using a detection device, which includes a positioning block, a support block, and a positioning pin adapted to the size of the eccentric hole. The positioning block has an outer ring adapted to the inner hole of the thin-walled cylinder, and the thin-walled cylinder is fitted onto the outer ring for detection and positioning. The support block includes a base plate and a support plate perpendicular to the base plate, and a detection reference surface is provided on the support plate. The detection reference surface is coplanar with the central axis of the thin-walled cylinder. After the positioning pin is inserted into the eccentric hole, the axis of the positioning pin is adjusted to be parallel to the lower end face of the thin-walled cylinder, and the position of the thin-walled cylinder is adjusted until the axis of the positioning pin is parallel to the detection reference surface. The eccentricity is obtained by detecting the distance between the axis of the positioning pin and the detection reference surface.

2. The method for detecting the eccentricity of an eccentric hole in a thin-walled cylinder according to claim 1, characterized in that, Multiple locating pins are grouped according to the tolerance of the eccentric hole. During the inspection, the largest diameter locating pin is first inserted into the eccentric hole until a locating pin of the appropriate size is selected.

3. The method for detecting the eccentricity of an eccentric hole in a thin-walled cylinder according to claim 1, characterized in that, The positioning block also includes a positioning plate disposed below the outer ring, and the lower end face of the thin-walled cylinder contacts and positions itself with the positioning plate.

4. The method for detecting the eccentricity of an eccentric hole in a thin-walled cylinder according to claim 1, characterized in that, The detection device also includes a go / no-go gauge, which is used to insert between the detection reference surface and the locating pin to detect the eccentricity. The go / no-go gauge includes a go end and a no-go end.

5. The method for detecting the eccentricity of an eccentric hole in a thin-walled cylinder according to claim 1, characterized in that, The end of the positioning pin inserted into the eccentric hole is a conical end.

6. The method for detecting the eccentricity of an eccentric hole in a thin-walled cylinder according to claim 1, characterized in that, The detection device also includes a pressure plate, which is arranged in parallel with the positioning plate. The lower surface of the pressure plate contacts the thin-walled cylinder to press and fix the thin-walled cylinder.

7. The method for detecting the eccentricity of an eccentric hole in a thin-walled cylinder according to claim 6, characterized in that, The pressure plate and the positioning block are connected by clamping screws.

8. The method for detecting the eccentricity of an eccentric hole in a thin-walled cylinder according to claim 1, characterized in that, The detection device also includes a base, and a positioning block and a support block are all mounted on the base.

9. The method for detecting the eccentricity of an eccentric hole in a thin-walled cylinder according to claim 8, characterized in that, The positioning block and the support block are both connected to the base by screws.

Images