A method for detecting the coaxiality and end face parallelism of large-diameter perforated holes

Abstract

This invention relates to the field of coaxiality and parallelism testing technology, specifically disclosing a method for testing the coaxiality and end-face parallelism of large-diameter multi-holes. The method requires a fixture for coaxiality and parallelism testing. The fixture includes a support base with two positioning pins and at least two support pins at its bottom. The positioning pins are higher than the support pins. A mounting frame is installed on the support base, and a dial indicator is mounted on the mounting frame. When testing the coaxiality and parallelism of multi-holes and end-holes, the two positioning pins of the support base are pressed against the wall of the end-hole, and the support pins are placed on the upper end face of the end-hole. The dial indicator probe is attached to the wall or end face of the multi-hole. Then, the positioning pins of the support base are tightly pressed against the inner wall of the end-hole while rotating along the end-hole, and the maximum value of the dial indicator's runout per revolution is recorded. This solution addresses the current problems of high testing difficulty and unbalanced testing costs when testing the coaxiality of large-diameter workpieces with multi-holes in the middle.

Description

Technical Field

[0001] This invention relates to the field of coaxiality and parallelism detection technology, specifically to a method for detecting the coaxiality and end-face parallelism of large-diameter serial holes. Background Technology

[0002] Currently, when testing small workpieces or workpieces with small hole diameters, the coaxiality and parallelism of the workpiece are measured by mounting the workpiece on a rotating object. After ensuring the workpiece's center is aligned with the rotation center, the workpiece is rotated. During rotation, the dial indicator reading in contact with the workpiece fluctuates, and the coaxiality is determined based on this fluctuation. However, this conventional method suffers from difficulties in rotation and inaccurate measurement when testing large-diameter holes with through-holes in the middle. For example, for box-shaped workpieces with through-holes, a cross-sectional view of such a workpiece is attached. Figure 1 As shown, the workpiece includes end holes on the upper and lower end faces and through holes inside the workpiece. The minimum hole diameter of the workpiece is about 450mm. The large hole diameter and thick wall of the workpiece result in a large volume and weight of the workpiece, making it difficult to rotate and center the workpiece, which leads to inaccurate measurement of coaxiality.

[0003] For this type of workpiece, coordinate measuring machine (CMM) inspection can be used. CMM is a precision measurement method for inspecting workpieces and is widely used in modern industries such as machinery manufacturing and automotive manufacturing. Its advantages are accurate results, wide applicability, and the ability to inspect almost all geometric tolerances. However, its disadvantages include a large investment, the need for professionally trained operators, strict environmental requirements, the necessity of adequate supporting facilities, and high maintenance costs. Summary of the Invention

[0004] The present invention aims to provide a method for detecting the coaxiality and end face parallelism of large-diameter through-holes, so as to solve the problems of high detection difficulty and high detection cost in the current coaxiality detection of workpieces with large diameters and through-holes in the middle.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for detecting the coaxiality and end face parallelism of large-diameter serial holes requires the use of a fixture to detect the coaxiality and parallelism. The fixture includes a support base, with two positioning posts and at least two support posts at the bottom of the support base. The positioning posts are higher than the support posts. A mounting frame is installed on the support base, and a dial indicator is installed at the end of the mounting frame away from the support base.

[0007] When testing the coaxiality and parallelism of the through hole and the end hole, the two positioning pins of the support base are pressed against the hole wall of the end hole, the support pins are placed on the upper end face of the end hole, and the probe of the dial indicator is attached to the hole wall or end face of the through hole. Then the support base is moved so that the positioning pins of the support base are tightly pressed against the inner wall of the end hole of the workpiece and rotated more than one revolution along the end hole. The maximum value of the dial indicator runout for each revolution is recorded.

[0008] The principle and advantages of this scheme are as follows: In practical applications, when coaxiality testing of workpieces with through holes is required, the two positioning pins of the support base are simultaneously pressed tightly against the wall of the end hole of the workpiece, and the probe of the dial indicator is pressed against the wall of the through hole. The inspector manually pulls the support base to move it, so that the positioning pins of the support base are pressed tightly against the inner wall of the end hole of the workpiece while rotating along the end hole. The number of rotations can be 2 or 3. The maximum value of the dial indicator runout in each rotation is recorded, and then the average value is calculated, which is the measured coaxiality between the end hole and the through hole. Then, the position of the dial indicator probe is changed so that the dial indicator probe acts on the end face of the through hole. Similarly, the inspector moves the positioning pins of the support base to rotate more than one rotation along the inner wall of the end hole, recording the maximum runout value of the dial indicator in each rotation. Then, the average value of the maximum runout values ​​in all rotations is taken, which is the parallelism between the end face of the end hole and the end face of the through hole.

[0009] Compared to existing technologies, this solution eliminates the need for coordinate measuring machine (CMM) inspection, reducing testing equipment costs and maintenance costs. Compared to conventional testing methods that require centering the workpiece and rotating it, this solution eliminates the need for workpiece centering and rotation, even for large workpieces. The operator simply holds the support base and rotates it around the center of the end hole while it is flush against the end hole wall to test the coaxiality and parallelism of the end hole and the through hole. The testing method is simple, cost-effective, and greatly ensures accuracy by eliminating the problem of workpiece centering.

[0010] Preferably, as an improvement, before the coaxiality and parallelism tests, the dimensional tolerances and geometric tolerances of the workpiece's through holes are first tested to ensure that the dimensional tolerances and geometric tolerances of the through hole wall and the upper and lower end faces of the through holes are qualified.

[0011] Preferably, as an improvement, after the coaxiality and parallelism of the upper end hole and the through hole of the workpiece are tested, the workpiece is rotated 180° so that the end hole originally located at the bottom of the workpiece becomes the end hole at the top of the workpiece. Then, the coaxiality and parallelism of the upper end hole and the through hole of the rotated workpiece are tested using the same method.

[0012] Beneficial effects: When using this solution to inspect the coaxiality and parallelism of box-shaped workpieces with end holes at the top and bottom and a through hole in the middle, the through hole is used as the reference. To ensure the accuracy of the inspection, the through hole needs to be inspected in advance to ensure that the dimensional tolerances and geometric tolerances of the hole wall, the top and bottom end faces of the through hole are within the design range. In other words, after the through hole is found to be in a qualified state, the coaxiality and parallelism of the end holes and the through hole are then inspected.

[0013] Furthermore, this solution uses the central perforation as a reference, which ensures that the mounting bracket used in the testing process does not need to be very long, thus reducing the length of the cantilever section of the mounting bracket, reducing the probability of instability of the dial indicator at the cantilever end, and ensuring the reliability of the test. At the same time, it also allows the testers to easily read the data on the dial indicator when the aperture is large and the measurement depth is relatively shallow.

[0014] Preferably, as an improvement, the mounting bracket includes a first connecting rod, a second connecting rod, and a clamping assembly. The first connecting rod is fixedly mounted on the support base. There are two clamping assemblies, one of which is used to connect the second connecting rod to the first connecting rod, and the other is used to connect the second connecting rod to the dial indicator. The clamping assembly allows the overall length formed by the second connecting rod and the first connecting rod to be adjustable. The clamping assembly allows the dial indicator to rotate and move relative to the second connecting rod.

[0015] Beneficial effects: Through the specific structural design of the mounting bracket, the overall length of connecting rod one and connecting rod two can be adjusted, thereby adapting to the coaxiality and parallelism testing of workpieces with different depths. Furthermore, the dial indicator can rotate and move relative to connecting rod two, enabling it to test workpieces with more different hole diameters, thus improving the adaptability of this testing method.

[0016] Preferably, as an improvement, the clamping assembly includes a receiving seat, a locking element, a U-shaped clamping plate, and a sleeve. The receiving seat is provided with a stud, and the locking element is threaded onto the stud. A through hole perpendicular to the axial direction of the stud is provided on a section of the receiving seat away from the stud. Two clamping plates of the U-shaped clamping plate slide between the through hole and the stud, and a clamping opening is formed between the two clamping plates of the U-shaped clamping plate, which is located on the outside of the receiving seat. The sleeve is fitted onto the section of the receiving seat with the through hole, and the sleeve is provided with a strip hole facing the through hole. The sleeve can move axially along the receiving seat. One of the two connected parts is placed on the clamping opening, and the other is placed on the through hole.

[0017] Beneficial effects: The clamping assembly of this solution allows the locking component to press against one of the clamping pieces of the U-shaped clamp when the locking component is tightened, thus clamping the part in the clamping port. At the same time, the receiving seat moves the part in the through hole closer to the locking component, while the sleeve moves away from the locking component under the push of the U-shaped clamp, thus clamping the part in the through hole. In other words, only one tightening action of the locking component is needed to clamp both connected parts. When not locked, one of the two parts can rotate and move up and down relative to the clamping port, and the other can rotate and move up and down relative to the through hole, making it convenient to adjust the included angle between the two connected parts.

[0018] Preferably, as an improvement, the outer surface of the receiving seat is cylindrical. This design sets the outer surface of the receiving seat to a cylindrical surface, allowing the U-shaped clamp to rotate around the receiving seat before being tightened by the locking components and sleeve. This further increases the degree of freedom of one of the parts before locking, increases the range of relative position adjustment between the two connected parts, and facilitates the arrangement of dial indicators in different orientations on the same mounting frame. This meets the coaxiality and parallelism testing requirements of workpieces with different depths and hole diameters, improving the practicality of this inspection tool method.

[0019] Preferably, as an improvement, the number of support columns is three, and the line connecting the three support columns forms a triangle.

[0020] Preferably, as an improvement, one of the three support columns is equidistant from two positioning columns, and the remaining two support columns are symmetrically arranged about the support column.

[0021] Preferably, as an improvement, the surface of the positioning post is provided with a quenching layer to improve the hardness and wear resistance of the positioning post.

[0022] Preferably, as an improvement, a handle is installed on the end face of the support base away from the positioning post and the support post, so as to make it easier for the support base to rotate around the end hole. Attached Figure Description

[0023] Figure 1 This is a front sectional view of the box-type workpiece to which this invention pertains.

[0024] Figure 2 This is a front view schematic diagram of the coaxiality detection of a workpiece according to Embodiment 1 of the present invention.

[0025] Figure 3 This is a front view schematic diagram of the workpiece during parallelism detection according to Embodiment 1 of the present invention.

[0026] Figure 4 This is a bottom view of Embodiment 1 of the present invention.

[0027] Figure 5This is a three-dimensional structural diagram of the inspection fixture according to Embodiment 2 of the present invention.

[0028] Figure 6 for Figure 5 A schematic diagram of the three-dimensional structure from another perspective.

[0029] Figure 7 This is a three-dimensional structural diagram of the clamping assembly in Embodiment 2 of the present invention.

[0030] Figure 8 for Figure 7 Exploded view of the clamping components. Detailed Implementation

[0031] The following detailed description illustrates the specific implementation method:

[0032] The reference numerals in the accompanying drawings include: support base 10, positioning post 11, support post 12, handle 13, mounting bracket 20, dial indicator 30, connecting rod 1, connecting rod 2, clamping assembly 3, receiving seat 31, locking element 32, U-shaped clamping plate 33, sleeve 34, strip hole 341, stud 311, through hole 312, clamping port 331, and threaded hole 100.

[0033] Example 1

[0034] Combination Figure 2 and Figure 4 As shown, a method for detecting the coaxiality and parallelism of large-diameter perforated holes requires the use of a fixture for coaxiality and parallelism testing. The fixture includes a support base 10, with two positioning posts 11 and at least two support posts 12 fixed to the bottom of the support base 10. The positioning posts 11 are higher than the support posts 12. A mounting bracket 20 is mounted on the support base 10, and a dial indicator 30 is mounted on the end of the mounting bracket 20 away from the support base 10. The two positioning posts 11 are symmetrically distributed about the mounting bracket 20. Specifically, there are three support posts 12, and the line connecting the three support posts 12 forms a triangle. Among the three support posts 12, one support post 12 is equidistant from the two positioning posts 11, and the remaining two support posts 12 are symmetrically arranged about the first support post 12. The surface of the positioning posts 11 is provided with a hardened layer to improve the hardness and wear resistance of the positioning posts 11. A handle 13 is mounted on the end face of the support base 10 away from the positioning posts 11 and support posts 12.

[0035] A method for detecting the coaxiality and end-face parallelism of a 100mm diameter perforated bore, as detailed below:

[0036] Step 1: First, check the dimensional tolerances and geometric tolerances of the 100mm hole. Only after the inspection is passed can you proceed to Steps 2 and 3.

[0037] Step 2: Coaxiality test of the upper hole and the through hole 100: Place the two positioning pins 11 of the support base 10 tightly against the hole wall of the upper hole of the workpiece. Place the support pin 12 on the end face of the upper hole. Adjust the position of the dial indicator 30 relative to the mounting bracket 20 so that the probe of the dial indicator 30 is against the hole wall of the through hole 100. The inspector pulls the handle 13 of the support base 10 by hand, causing the positioning pin 11 of the support base 10 to tightly engage with the inner wall of the end hole of the workpiece while rotating along the upper hole. The number of rotations can be 2, 3, or even more. Take the maximum value of the dial indicator 30's runout in each rotation, and then take the average of all the maximum runout values. This is the measured coaxiality of the upper hole and the through hole 100.

[0038] Step 3: Parallelism test of the upper end hole and the pier 100: Make the two positioning pins 11 of the support base 10 simultaneously close to the hole wall of the upper end hole of the workpiece, and place the support pin 12 on the end face of the upper end hole. Change the position of the dial indicator 30 on the mounting bracket so that the probe of the dial indicator 30 is close to the upper end face of the pier 100. The inspector pulls the handle 13 of the support base 10 by hand, so that the positioning pin 11 of the support base 10 is tightly attached to the inner wall of the end hole of the workpiece and rotates along the end hole. The number of rotations can be 2 or 3. Take the maximum value of the dial indicator 30 runout in each rotation, and then take the average of the maximum runout values ​​of all rotations. This is the measured parallelism between the outer end face of the part and the end face of the pier 100.

[0039] Step 4: Use a lifting device to rotate the workpiece so that the lower end hole of the workpiece is at the top, while the upper end hole, which has already been tested for coaxiality and parallelism, is at the bottom.

[0040] Step 5: Following the operation method in Step 3, check the parallelism between the upper end hole of the rotated workpiece and the through hole 100.

[0041] Step 6: Following the operation method in Step 2, check the coaxiality of the upper end hole and the through hole 100 of the rotated workpiece.

[0042] Compared with existing technologies, this embodiment does not require coordinate measuring machine (CMM) inspection, which reduces the cost of testing equipment and maintenance. Compared with existing conventional testing methods that require centering the workpiece and rotating it, this embodiment does not require centering the workpiece or rotating large-sized workpieces. The tester only needs to hold the handle 13 of the support base 10 and rotate the support base 10 around the center of the end hole while it is against the end hole wall to achieve the coaxiality and parallelism test of the end hole and the through hole 100. The testing method is simple and the testing cost is low. Moreover, since there is no problem of the workpiece center not being able to be aligned, the accuracy of the test is greatly guaranteed.

[0043] Example 2

[0044] Combination Figures 5 to 8Example 2 further improves the mounting bracket 20 based on Example 1. The specific improvements to the mounting bracket 20 are as follows:

[0045] Mounting bracket 20 includes connecting rod 1, connecting rod 2, and clamping assembly 3. Connecting rod 1 is fixedly mounted on support base 10. There are two clamping assemblies 3. One clamping assembly 3 is used to connect connecting rod 2 to connecting rod 1, and the other clamping assembly 3 is used to connect connecting rod 2 to dial indicator 30.

[0046] Each clamping assembly 3 includes a receiving seat 31, a locking element 32, a U-shaped clamping plate 33, and a sleeve 34. A stud 311 is machined on the receiving seat 31, and the locking element 32 is threaded onto the stud 311. A through hole 312 perpendicular to the axial direction of the stud 311 is machined on a section of the receiving seat 31 away from the stud 311. Two clamping plates of the U-shaped clamping plate 33 slide on a middle section of the receiving seat 31 between the through hole 312 and the stud 311. A clamping opening 331 is formed between the two parts, and the clamping opening 331 is located outside the receiving seat 31. The sleeve 34 is fitted onto the section of the receiving seat 31 with the through hole 312. The sleeve 34 has a strip hole 341 that is directly opposite the through hole 312. The outer surface of the receiving seat 31 that mates with the U-shaped clamp 33 and the sleeve 34 is cylindrical. The sleeve 34 can move along the axial direction of the receiving seat 31. One of the two connected parts is placed on the clamping opening 331 and the other is placed on the through hole 312.

[0047] Taking the connection of connecting rod 1 and connecting rod 2 as an example, connecting rod 1 is placed on the clamping port 331, and connecting rod 2 is placed on the through hole 312 of the receiving seat 31. After the relative positions of connecting rod 1 and connecting rod 2 are adjusted, the locking member 32 is screwed on, so that the locking member 32 abuts against one of the clamping pieces of the U-shaped clamping plate 33, the other clamping piece of the U-shaped clamping plate 33 abuts against the sleeve 34, and the sleeve 34 abuts against connecting rod 2. During this process, the U-shaped clamping plate 33 is compressed and... The clamping port 331 clamps the connecting rod 1; at the same time, the receiving seat 31 drives the connecting rod 2 in the through hole 312 to approach the locking member 32, while the sleeve 34 is pushed away from the locking member 32 by the U-shaped clamping plate 33, so that the connecting rod 2 is squeezed by the sleeve 34 and the through hole 312 of the receiving seat 31. That is, only one turning and locking action of the locking member 32 is needed to clamp both the connected connecting rod 1 and the connecting rod 2. The operation is very simple.

[0048] When the locking member 32 is not locked, one of the two clamped parts can rotate and move up and down relative to the clamping port 331, and the other can rotate and move up and down relative to the through hole 312. At the same time, the receiving seat 31 can also rotate around the U-shaped clamping plate 33, which makes it easy to adjust the included angle between the two connected parts. This ensures that the dial indicator 30 installed on the clamping assembly 3 can be adjusted to the position for coaxiality testing of the parallelism test box. It also ensures that the same mounting bracket 20 can meet the coaxiality and parallelism testing requirements of workpieces with different depths and hole diameters, thus improving the applicability and practicality of this testing method.

[0049] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for detecting the coaxiality and end-face parallelism of large-diameter perforated holes, characterized in that, A fixture is required to test coaxiality and parallelism. The fixture includes a support base, with two positioning posts and at least two support posts at the bottom of the support base. The positioning posts are higher than the support posts. A mounting bracket is installed on the support base, and a dial indicator is installed at the end of the mounting bracket away from the support base. The detection process includes the following steps: Step 1: First, check the dimensional tolerances and geometric tolerances of the vias. Only after the inspection is passed can you proceed to Steps 2 and 3. Step 2: Coaxiality test of the upper hole and the through hole: Make the two positioning pins of the support base press tightly against the hole wall of the upper hole of the workpiece at the same time. Place the support pin on the end face of the upper hole. Adjust the position of the dial indicator relative to the mounting bracket so that the probe of the dial indicator is pressed against the hole wall of the through hole. Make the positioning pin of the support base press tightly against the inner wall of the end hole of the workpiece and rotate it more than one revolution along the end hole. Record the maximum value of the dial indicator runout for each revolution. Step 3, Parallelism test of the upper hole and the through hole: Make the two positioning pins of the support base tightly against the hole wall of the upper hole of the workpiece at the same time. Place the support pin on the end face of the upper hole. Change the position of the dial indicator on the mounting bracket so that the probe of the dial indicator is attached to the upper end face of the through hole. Make the positioning pin of the support base tightly against the inner wall of the end hole of the workpiece and rotate it more than one revolution along the end hole. Record the maximum value of the dial indicator runout for each revolution. Step 4: Use a lifting device to rotate the workpiece so that the lower end hole of the workpiece is at the top, while the upper end hole, which has already been tested for coaxiality and parallelism, is at the bottom. Step 5: Following the operation method in Step 3, check the parallelism between the upper end hole and the through hole of the reversed workpiece; Step 6: Following the operation method in Step 2, check the coaxiality of the upper end hole and the through hole of the rotated workpiece.

2. The method for detecting the coaxiality and end-face parallelism of large-diameter perforated holes according to claim 1, characterized in that: The mounting bracket includes a first connecting rod, a second connecting rod, and a clamping assembly. The first connecting rod is fixedly mounted on the support base. There are two clamping assemblies. One clamping assembly is used to connect the second connecting rod to the first connecting rod, and the other clamping assembly is used to connect the second connecting rod to the dial indicator. The clamping assembly allows the overall length formed by the second connecting rod and the first connecting rod to be adjustable. The clamping assembly allows the dial indicator to rotate and move relative to the second connecting rod.

3. The method for detecting the coaxiality and end-face parallelism of large-diameter perforated holes according to claim 2, characterized in that: The clamping assembly includes a receiving seat, a locking element, a U-shaped clamping plate, and a sleeve. The receiving seat is provided with a stud, and the locking element is threaded onto the stud. A through hole perpendicular to the axial direction of the stud is provided on a section of the receiving seat away from the stud. Two clamping plates of the U-shaped clamping plate slide between the through hole and the stud, and a clamping opening is formed between the two clamping plates of the U-shaped clamping plate, which is located on the outside of the receiving seat. The sleeve is fitted onto the section of the receiving seat with the through hole, and a strip hole is provided on the sleeve facing the through hole. The sleeve can move axially along the receiving seat. One of the two connected parts is placed on the clamping opening, and the other is placed on the through hole.

4. The method for detecting the coaxiality and end-face parallelism of large-diameter perforated holes according to claim 3, characterized in that: The outer surface of the receiving seat is cylindrical.

5. The method for detecting the coaxiality and end-face parallelism of large-diameter perforated holes according to claim 1, characterized in that: The number of support columns is three, and the line connecting the three support columns forms a triangle.

6. The method for detecting the coaxiality and end-face parallelism of large-diameter serial holes according to claim 5, characterized in that: Of the three support columns, one support column is equidistant from two positioning columns, and the remaining two support columns are symmetrically arranged about the support column.

7. The method for detecting the coaxiality and end-face parallelism of large-diameter perforated holes according to claim 1, characterized in that: The surface of the positioning post is provided with a quenching layer.

8. The method for detecting the coaxiality and end-face parallelism of large-diameter perforated holes according to claim 1, characterized in that: A handle is installed on the end face of the support base away from the positioning column and the support column.

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