Device for measuring diameter of inner hole of thin wall

Abstract

The utility model discloses a measuring device for measuring the diameter of a thin-wall inner hole, which comprises a laser triangular displacement sensor, a mounting plate and a Morse taper sleeve assembly, the laser triangular displacement sensor is fixedly connected to the mounting plate, the mounting plate is fixedly connected to the outer end of the Morse taper sleeve assembly, and the other end of the Morse taper sleeve assembly is fixedly connected to a machine tool tailstock. A light beam of the laser triangular displacement sensor is emitted to the inner hole wall of the workpiece, the light beam emitting direction is coplanar with the axis of the Morse taper sleeve assembly, and a light beam emitting point is kept coaxial with the axis of the Morse taper sleeve assembly. The device is directly installed on a tailstock of a machine tool to conveniently measure the material and the inner diameter of the machined thin-wall workpiece, the laser triangular displacement sensor is used for measurement, the environmental interference resistance is enhanced, the measurement precision is improved, and the problem that the diameter of an inner hole of the thin-wall workpiece is greatly influenced by the field measurement precision and the field measurement environment is solved.

Description

Technical Field

[0001] The utility model relates to a measuring device for measuring the inner diameter of a thin-walled hole, belonging to the technical field of inner diameter measuring equipment for thin-walled workpieces. Background Technique

[0002] With the development of mechanical equipment towards complexity and precision, the detection requirements for the processing quality of thin-walled workpieces required by these equipment are also continuously improving. Thin-walled workpieces are widely used in many fields such as aerospace, weaponry, precision instruments, and daily life due to their characteristics of material saving, light weight, and compact structure. However, the detection of thin-walled workpieces belongs to a measurement problem. Compared with the measurement of traditional workpieces, the stiffness of thin-walled workpieces has a large gap. During measurement, due to the involvement of disassembly, it is easy for the deformation generated by thin-walled workpieces to be relatively large compared to their own dimensions. At present, most domestic and foreign thin-walled inner diameter measuring instruments still use contact measuring instruments such as micrometers and steel tape measures. However, these measuring tools are complex and bulky, have low measurement efficiency, and are easily affected by operators and measurement environments. Of course, non-contact measurements such as the Doppler effect method, roller method, marking method, laser interferometer, and laser lever method can also obtain high measurement accuracy. However, considering the disadvantages that the roller method and marking method require the workpiece to rotate and are not suitable for thin-walled workpieces; the laser interferometer and Doppler effect method require a guide rail; and the laser lever method has a small measurement range. Summary of the Invention

[0003] The technical problem to be solved by the utility model is: to provide a measuring device for measuring the inner diameter of a thin-walled hole, improving the convenience of inner diameter measurement, enhancing its anti-environmental interference ability, and improving the measurement accuracy, so as to solve the problem that the inner diameter of thin-walled workpieces is greatly affected by on-site measurement accuracy and on-site measurement environment.

[0004] The technical solution adopted by the utility model is: a measuring device for measuring the inner diameter of a thin-walled hole, including a laser triangulation displacement sensor, a mounting plate, and a Morse taper sleeve assembly. The laser triangulation displacement sensor is fixedly connected to the mounting plate, the mounting plate is fixedly connected to the outer end of the Morse taper sleeve assembly, the other end of the Morse taper sleeve assembly is fixedly connected to the tailstock of the machine tool, the beam of the laser triangulation displacement sensor is directed towards the inner hole wall of the workpiece, and the direction of the beam is in the same plane as the axis of the Morse taper sleeve assembly and the beam emission point is coaxial with the axis of the Morse taper sleeve assembly.

[0005] Further, the above laser triangulation displacement sensor is connected to a display screen.

[0006] Further, the above display screen is fixedly connected to the Morse taper sleeve assembly through a locking bushing.

[0007] Further, a display screen support plate is fixedly connected to the above locking bushing, and the display support plate is fixedly connected to the display screen.

[0008] Further, the above-mentioned locking bushing is sleeved on the cylindrical section of the Morse taper bushing assembly, and after the locking handwheel is radially screwed into the locking bushing, it abuts against the Morse taper bushing assembly for locking.

[0009] Further, the above-mentioned mounting plate is provided with a bent plate, and the bent plate is fixedly connected to the outer end of the Morse taper bushing assembly through a positioning pin and a screw.

[0010] Further, the above-mentioned Morse taper bushing assembly includes a standard Morse reducing sleeve and a Morse taper plug inserted into the outer end of the standard Morse reducing sleeve. The standard Morse reducing sleeve is fixed by a threaded tie rod after being inserted into the tapered hole of the tailstock.

[0011] Further, the above-mentioned laser triangulation displacement sensor is fixedly connected to the mounting plate through a tensioning structure.

[0012] The beneficial effects of the present utility model: Compared with the prior art, the present utility model is directly installed on the tailstock of the machine tool to measure the inner diameter of the thin-walled part. The inner diameter measurement is convenient. The laser triangulation displacement sensor is used for measurement, which enhances the anti-environmental interference ability and improves the measurement accuracy. It solves the problem that the inner hole diameter of the thin-walled workpiece is greatly affected by the on-site measurement accuracy and the on-site measurement environment. The beam point of the laser probe of the machine tool tailstock and the laser triangulation displacement sensor is on the same plane and the emitted beam is perpendicular to the axis of the machine tool tailstock, so as to ensure that the beam emission point is coaxial with the axis of the Morse taper bushing assembly. Therefore, the accuracy is relatively high compared with the previous method. And because the tailstock is detachable, this device can adapt to the characteristics of quick installation, convenient measurement and simple operation for the on-site operators during processing; the present utility model is applicable to the on-line detection of thin-walled parts processed by CNC machine tools with tailstocks. Description of the Drawings

[0013] Figure 1 is a schematic side sectional structure view of the measuring device for the inner diameter of the thin-walled hole;

[0014] Figure 2 is a schematic top sectional structure view of the measuring device for the inner diameter of the thin-walled hole;

[0015] Figure 3 is a schematic front view structure view of the measuring device for the inner diameter of the thin-walled hole;

[0016] Figure 4 is Figure 3 the enlarged structure view of part A in

[0017] Figure 5 is a schematic front view structure view of the measuring device for the inner diameter of the thin-walled hole without installing the laser triangulation displacement sensor;

[0018] Figure 6 is a schematic front view structure view of the mounting plate;

[0019] Figure 7 It is a schematic top view structure of the mounting plate;

[0020] Figure 8 It is a schematic front view structure of the Morse taper sleeve assembly;

[0021] Figure 9 It is a schematic diagram of the structure of the laser triangulation displacement sensor and the direction of its light beam.

[0022] In the figure, 1. Laser triangulation displacement sensor, 2. Mounting plate, 3. Morse taper sleeve assembly, 4. Machine tool tailstock, 5. Display screen, 6. Locking bushing, 7. Display screen support plate, 8. Locking handwheel, 9. Bent plate, 10. Locating pin, 11. Screw, 12. Standard Morse reducing sleeve, 13. Morse taper plug, 14. Threaded pull rod, 15. Expansion sleeve, 16. Expansion core, 17. Screw, 18. Annular groove, 19. Workpiece. Specific implementation mode

[0023] The following further introduces the present utility model in conjunction with the attached drawings and specific embodiments.

[0024] Embodiment 1: As Figures 1-9 shown, a measuring device for measuring the diameter of a thin-walled inner hole includes a laser triangulation displacement sensor 1, a mounting plate 2 and a Morse taper sleeve assembly 3. The laser triangulation displacement sensor 1 is fixedly connected to the mounting plate 2, the mounting plate 2 is fixedly connected to the outer end of the Morse taper sleeve assembly 3, the other end of the Morse taper sleeve assembly 3 is fixedly connected to the machine tool tailstock 4, the light beam of the laser triangulation displacement sensor 1 is directed at the inner hole wall of the workpiece 19, and the direction of the light beam is coplanar with the axis of the Morse taper sleeve assembly 3 and the light beam exit point is coaxial with the axis of the Morse taper sleeve assembly 3.

[0025] In order to facilitate viewing the detection data, the laser triangulation displacement sensor 1 is connected to the display screen 5, and the detected data is read and displayed through the display screen, so that the reading of the laser displacement sensor can be quickly observed. The display screen 5 is fixedly connected to the Morse taper sleeve assembly 3 through the locking bushing 6, and the quick installation of the display screen can be realized.

[0026] Wherein, a display screen support plate 7 is vertically and fixedly connected to the upper side of the locking bushing 6, and the upper end of the display support plate 7 is horizontally and fixedly connected to the display screen 5, which is convenient and fast to install, the connection is stable and reliable, and it is also convenient to observe the data.

[0027] Furthermore, the above-mentioned locking bushing 6 is sleeved on the cylindrical section of the Morse taper sleeve assembly 3 (the cylindrical section of the Morse taper plug), and the screw section of the locking handwheel 8 is radially inserted into the locking bushing 6 and then abuts against the Morse taper sleeve assembly 3 for locking. After the locking bushing 6 is sleeved into the cylindrical section, it is locked by rotating the locking first wheel. An annular groove is provided on the cylindrical section to facilitate the axial limit of the inner end thread of the locking handwheel and limit the axial movement of the locking bushing 6.

[0028] To ensure that the beam of the laser triangulation displacement sensor is coplanar with the axis of the Morse taper sleeve assembly 3, a vertical L-shaped bending plate 9 is provided on the right side of the mounting plate 2. The L-shaped bending plate 9 includes a rear side plate and a right side plate perpendicularly connected to the front side of the right end of the rear side plate. The mounting plate 2 is parallel to the rear side plate, and the rear side plate, the right side plate and the mounting plate 2 are of an integral structure. The bending plate 9 is fixedly connected to the outer end of the Morse taper sleeve assembly 3 (i.e., the end face of the Morse taper plug 13) through a positioning pin 10 and a screw 11. After positioning the right vertical plate of the bending plate 9 with the end face of the Morse taper plug 13 through the positioning pin 10, it is locked with a screw. The positioning is accurate and the installation is stable and reliable. The bending structure realizes the avoidance of space, facilitating the arrangement of the emitted beam and the reflected beam of the laser triangulation displacement sensor to be coplanar with the axis of the Morse taper sleeve assembly 3. The front side of the bending plate 9 is lower than the installation mating surface of the mounting plate 2 (i.e., the A surface as shown in Figure 5 ), reducing the machining area and improving the flat machining accuracy. The distance error between the end face of the mounting plate 2 and the Morse taper sleeve assembly 3 meets the measurement error requirements.

[0029] Among them, the Morse taper sleeve assembly 3 includes a standard Morse reducing sleeve 12 and a Morse taper plug 13 inserted into the outer end of the standard Morse reducing sleeve 12. After the standard Morse reducing sleeve 12 is inserted into the installation hole of the machine tool tailstock 4, the standard Morse reducing sleeve 12 is fixed on the machine tool tailstock 4 by a threaded tie rod 14. The tapered fit of the standard Morse reducing sleeve 12 and the Morse taper plug 13 can improve the self-positioning accuracy.

[0030] To accurately install the laser triangulation displacement sensor on the mounting plate 2, the laser triangulation displacement sensor 1 is fixedly connected to the mounting plate 2 through a tensioning structure. The tensioning structure includes a tensioning sleeve 15, a tensioning core 16 and a screw 17. The tensioning sleeve 15 is a stepped cylinder. The large end extends into the circular hole of the mounting plate 2, and the small end extends into the installation hole on the laser displacement sensor. The outer cylindrical surface of the tensioning core 16 is a conical surface, and the inner hole at the large end of the tensioning sleeve 15 is a conical hole. The tensioning core 16 is placed in the conical hole, and the screw 17 is inserted from the other end of the tensioning sleeve and screwed to the tensioning core 16. The tensioning method of the tensioning core and the conical hole can achieve self-positioning and greatly improve the installation accuracy.

[0031] Embodiment 2: A measuring method for a measuring device for measuring the inner diameter of a thin wall includes the following steps:

[0032] S1: Assemble the inner diameter measuring device, including a Morse taper sleeve assembly related to the machine tool tailstock, a mounting plate for installing a laser triangulation displacement sensor (laser triangulation displacement sensor) and the laser triangulation displacement sensor. Since the outer shapes of the Morse taper sleeve and the mounting plate are quite different and in line with the design principle, the Morse taper sleeve and the mounting plate are divided into two parts. After rough machining of the mounting plate, it is assembled and fixed with the already finely machined Morse taper sleeve assembly into one body, and then the installation reference surface and installation holes of the mounting plate are machined;

[0033] S2: The installation reference plane of the laser triangulation displacement sensor, i.e., the first reference plane (such as Figure 5 the indicated surface A), should be parallel to the laser outgoing beam (such as Figure 1 the outgoing beam B in Figure 1 ) and the reflected beam (such as Figure 5 the reflected beam C in

[0034] ); the second reference plane (such as Figure 1 the indicated surface D) should be perpendicular to the first reference plane, and the second reference plane should be parallel to the laser outgoing beam; for the LTP150 laser triangulation displacement sensor, the first reference plane is the surface with dimensions 80mm * 92mm (not the cover plate surface), parallel to the laser outgoing beam and the reflected beam; the surface with dimensions 80.0 * 36.0 is the second reference plane of the laser triangulation displacement sensor, 12mm away from the outgoing beam; this laser triangulation displacement sensor has two Φ5 mounting holes with a spacing of 69mm, and these mounting holes should have the function of positioning pin holes; ) and the inner diameter measurement range Move the laser triangulation displacement sensor downward by 69mm for positioning (move the distance between the positioning holes of one laser triangulation displacement sensor, corresponding to the standard ring gauge ), and the inner diameter measurement range Then the total inner diameter measurement range can be from Therefore, according to the requirements of the measured workpiece range, different laser triangulation displacement sensors can be selected to achieve different range expansions;

[0035] S4: The mounting plate is provided with 3 Φ5 mounting holes from top to bottom, with a spacing of 69mm; the laser triangulation displacement sensor is mounted with the upper and middle holes, and the inner diameter measurement range is Φ220 - Φ380mm; the laser triangulation displacement sensor is mounted with the middle and lower holes, and the inner diameter measurement range is Φ350 - Φ518mm; it can meet the requirements of the inner diameter measurement range of Φ300 - Φ500mm, without the need to add another radial displacement link, the device is simpler, and it is beneficial for use in the machining site;

[0036] S5: Such as Figure 8 Put a liquid crystal display bracket (including a locking bushing and a display support plate) on the cylindrical section at the front end of the Morse taper sleeve assembly , lock it with a handwheel, and fix the liquid crystal display on it to display the measured value.

[0037] S6: The designed device should ensure that the plane formed by the laser outgoing beam and the reflected beam of the laser triangulation displacement sensor should pass through the machining center line of the machine tool (the connection line of the machine tool spindle and the machine tool tailstock axis), and it should ensure that the outgoing beam is perpendicular to the machining center line of the machine tool.

[0038] This utility model is for the diameter of the measured workpiece Diameter tolerance H6, The selected laser triangulation displacement sensor has a measuring range of 150mm ± 40mm, a reproducibility of 1.6 microns, and the accuracy meets the measurement requirements; the mounting plate connecting the bending plate is used to fix the laser triangulation displacement sensor, and the fixed surface of the mounting plate should ensure that the laser emission axis passes through the axis of the Morse taper cannula and is perpendicular to the axis of the Morse taper cannula. If the offset is 0.767mm, the diameter can be reduced by 2 microns. During measurement, move the tailstock of the machine tool so that the beam of the laser triangulation displacement sensor shoots at the inner hole wall of the workpiece, and the laser triangulation displacement sensor displays the measured value. The combined result of the measured value and the initial value of the laser triangulation displacement sensor is the measurement result of the inner hole diameter of the workpiece; the workpiece can be rotated to several positions and the average value can be calculated.

[0039] The implementation calculation of the present invention is as follows:

[0040] Taking the nominal diameter 300 ring gauge as the measurement object, the ring gauge marking line size is 300.005mm. The three-coordinate measures 18 equally divided points of the ring gauge.

[0041] Establish an X~Y coordinate system with the center of the probe as the coordinate origin, and project the contour point r i onto the X~Y coordinate system (x i , y i ), that is, calculate

[0042]

[0043] Calculate the offset of the new coordinate system

[0044]

[0045] where a is the offset of the x-axis of the new coordinate, b is the offset of the y-axis of the new coordinate, n is the equally divided points collected per circle, and θ i is the radian value bisected after the number of points taken;

[0046] Calculate the coordinate value of the contour point r i in the new coordinate system

[0047]

[0048] Calculate the contour point r i in the radius r of the new coordinate system n

[0049]

[0050] Calculate the deviation based on the ring gauge marking line size:

[0051] Take r of serial number 1 and serial number 18 nIt is the measured value of the ring gauge marking line, and the deviation is less than the variation of the probe indication value of 1.6 μm.

[0052] Calculate the profile point r n and the difference Δ i

[0053]

[0054] is the average value of the measured value r1 of the ring gauge marking line and r 18 ;

[0055] Calculate the diameter of each profile point

[0056] D i = 2 × (Δ i + 150.0025)

[0057] Calculate the least squares circle diameter

[0058]

[0059] Calculate the roundness error ΔR

[0060] ΔD = D max - D min

[0061]

[0062] where D max is the maximum value of the measured diameter, and D min is the minimum value of the measured diameter.

[0063] The above is only the specific implementation manner of the present utility model, but the protection scope of the present utility model is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present utility model can easily think of changes or substitutions, which should all be covered within the protection scope of the present utility model. Therefore, the protection scope of the present utility model should be subject to the protection scope of the claimed rights.

Claims

1. A measuring device for measuring the diameter of a thin-walled inner hole, characterized in that: It includes a laser triangulation displacement sensor (1), a mounting plate (2) and a Morse taper sleeve assembly (3). The laser triangulation displacement sensor (1) is fixedly connected to the mounting plate (2). The mounting plate (2) is fixedly connected to the outer end of the Morse taper sleeve assembly (3). The other end of the Morse taper sleeve assembly (3) is fixedly connected to the tailstock (4) of the machine tool. The beam of the laser triangulation displacement sensor (1) shoots towards the inner hole wall of the workpiece (19), and the shooting direction of the beam is coplanar with the axis of the Morse taper sleeve assembly (3), and the beam emitting point is coaxial with the axis of the Morse taper sleeve assembly.

2. The measuring device for measuring the diameter of a thin-walled inner hole according to claim 1, characterized in that: The laser triangulation displacement sensor (1) is connected to the display screen (5).

3. A measuring device for measuring the inner diameter of a thin-walled hole according to claim 2, characterized in that: The display screen (5) is fixedly connected to the Morse taper sleeve assembly (3) through a locking bushing (6).

4. A device for measuring the diameter of a thin-walled inner hole according to claim 3, characterized in that: A display screen support plate (7) is fixedly connected to the locking bushing (6), and the display support plate (7) is fixedly connected to the display screen (5).

5. A device for measuring the diameter of a thin-walled inner hole according to claim 3 or 4, characterized in that: The locking bushing (6) is sleeved on the cylindrical section of the Morse taper sleeve assembly (3), and the locking handwheel (8) is radially screwed into the locking bushing (6) and then abuts against the Morse taper sleeve assembly (3) for locking.

6. A measuring device for measuring the diameter of a thin-walled inner hole according to any one of claims 1-4, characterized in that: The mounting plate (2) is provided with a bending plate (9), and the bending plate (9) is fixedly connected to the outer end of the Morse taper sleeve assembly (3) through a positioning pin (10) and a screw (11).

7. A measuring device for measuring the diameter of a thin-walled inner hole according to any one of claims 1-4, characterized in that: The Morse taper sleeve assembly (3) includes a standard Morse reducing sleeve (12) and a Morse taper plug (13) inserted into the outer end of the standard Morse reducing sleeve (12). The standard Morse reducing sleeve (12) is fixed by a threaded tie rod (14) after being inserted into the tapered hole of the tailstock.

8. A device for measuring the diameter of a thin-walled inner hole according to any one of claims 1-4, characterized in that: The laser triangulation displacement sensor (1) is fixedly connected to the mounting plate (2) through a swelling structure.

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