A Measuring Machine and Measuring Method for the Inner Bore Dimensions of a Gun Barrel

Abstract

The present invention discloses a measuring machine for the inner bore size of a gun barrel, which includes a gantry frame, a spectral confocal sensor and a controller. On one side of the gantry frame, there is a positioning and rotating device for fixing the gun barrel to be measured and driving the gun barrel to be measured to rotate. At a position near the top of the gantry frame and corresponding to the positioning and rotating device, there is a Z-direction moving device that moves along the Z axis. On the side of the Z-direction moving device and at a position corresponding to the positioning and rotating device, there is a sensor mounting assembly that moves along the Z axis. The spectral confocal sensor is arranged on the sensor mounting assembly, and the spectral confocal sensor is connected to the controller through an optical fiber. The present invention adopts the principle of spectral confocal and can realize the positioning and rotation of the gun barrel and the measurement of the inner bore size parameters.

Description

Technical Field

[0001] The present invention belongs to the field of measuring the inner bore size of a gun barrel, and particularly relates to a measuring machine and a measuring method for the inner bore size of a gun barrel. Background Art

[0002] Currently, the measurement of the inner bore size of a gun barrel is generally completed by optoelectronic methods, ray methods or optical image methods (industrial endoscope methods). However, for small-caliber firearms, since the minimum caliber of the gun barrel is 5.56 mm, optoelectronic measurement cannot be used. At the same time, the ray method system has too high a cost and too low a measurement efficiency. The optical image method (industrial endoscope method) applied to the measurement of the inner bore of a gun barrel mainly has the following two difficulties:

[0003] 1) Since the CCD camera images a regional image (440,000 pixels), when the camera moves along the X-axis direction of the tube and takes continuous photos, image stacking will occur. How to separate the stacked images taken before and after to obtain a complete image of the inner cavity of the X-tube, and then obtain relevant dimension parameters through image analysis. The related algorithms and software development are difficult. If the image processing is not good, it will directly lead to the distortion of the dimension values obtained based on the image processing.

[0004] 2) Whether using a three-dimensional stereo double-objective measurement lens or an ordinary double-objective stereo measurement lens, the mainstream level of the FOV (field of view) of the lens is in the range of 96° - 110°, and the best can only reach 120°. In theory, the lens needs to rotate three times to image a circle. Therefore, on the mechanical structure of the measuring device, it is necessary to cooperate with the feeding movement in the axial direction of the gun barrel and the rotational movement of the gun barrel circumference. Therefore, the mechanical structure of the equipment is not simplified, and the efficiency advantage is not obvious.

[0005] Therefore, a new method and a new device cooperating with this method are needed to meet the measurement of the internal dimensions of small-caliber firearms. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a measuring machine and a measuring method for the inner bore size of a gun barrel, which adopt the principle of spectral confocal, can realize the positioning rotation of the gun barrel and the measurement of the inner bore size parameters, aiming at the deficiencies of the above-mentioned prior art.

[0007] The technical solution adopted by the present invention is as follows: A measuring machine for the inner bore size of a gun barrel, comprising a gantry frame, a spectral confocal sensor, and a controller. On one side of the gantry frame, there is a positioning and rotating device for fixing the gun barrel to be measured and driving the gun barrel to be measured to rotate. At a position near the top of the gantry frame and corresponding to the positioning and rotating device, there is a Z-direction moving device that moves along the Z-axis. On the side of the Z-direction moving device and corresponding to the positioning and rotating device, there is a sensor mounting assembly that moves along the Z-axis. The spectral confocal sensor is arranged on the sensor mounting assembly, and the spectral confocal sensor is connected to the controller through an optical fiber.

[0008] In one embodiment, the gantry frame includes a loading platform. On the upper surface of the loading platform, two columns are symmetrically arranged, and a cross beam is provided at the tops of the two columns.

[0009] In one embodiment, the positioning and rotating device includes a positioning column arranged on the upper surface of the loading platform and a turntable arranged on the top of the loading platform and on one side of the positioning column. On one side of the positioning column close to the turntable, an upper fixture for fixing the upper end face of the gun barrel to be measured is provided through a connecting block. The connecting block is displaced along the Z-axis relative to the positioning column, and a lower fixture for fixing the lower end face of the gun barrel to be measured is provided on the turntable.

[0010] In one embodiment, the upper fixture includes a fixture body. Inside the fixture body, there is a fixture through-hole for fixing the upper end face of the gun barrel to be measured and allowing the sensor mounting assembly to pass through.

[0011] In one embodiment, several axial through-grooves extending along the axial direction to the middle of the fixture body are opened around the axis at one end face of the fixture body. The several axial through-grooves divide the fixture body into several fixing blocks.

[0012] In one embodiment, radial through-grooves are opened at one end of the several axial through-grooves far from the end face of the fixture body.

[0013] In one embodiment, the Z-direction moving device includes a guide rail base arranged on one side of the cross beam close to the positioning and rotating device. On one side of the guide rail base close to the positioning and rotating device, there is a linear guide rail extending along the Z-axis. Inside the linear guide rail, there is a probe seat that moves along the linear guide rail and is used for mounting the sensor mounting assembly.

[0014] In one embodiment, a driving device for driving the probe seat to move along the linear guide rail is provided on the lower surface of the probe seat.

[0015] In one embodiment, the sensor mounting assembly includes several connected extension rods arranged on the lower surface of the probe seat. The spectral confocal sensor is arranged on the lower surface of the lowermost extension rod.

[0016] The present invention also discloses a method for measuring the inner bore size of a gun barrel, which includes the following steps:

[0017] Step 10: Input and store the gun barrel type and the standard parameters of each gun barrel type, and set the measurement positions of each gun barrel type;

[0018] Step 20: Select the upper fixture and the lower fixture that match the model of the gun barrel to be measured, place the gun barrel to be measured on the lower fixture, and the connecting block drives the upper fixture to move downwards to fix the gun barrel to be measured;

[0019] Step 30: Select an extension rod that matches the length of the gun barrel to be measured, and install the spectral confocal sensor on the extension rod;

[0020] Step 40: The rotary table works to drive the gun barrel to be measured to rotate, and the driving device drives the probe seat to displace along the linear guide rail, driving the spectral confocal sensor to move into the gun barrel to be measured;

[0021] Step 50: Select the gun barrel type, and the controller retrieves the standard parameters corresponding to the selected gun barrel type. The measurement of the gun barrel starts. The driving device drives the probe seat to displace along the linear guide rail, driving the spectral confocal sensor to continuously move inside the gun barrel to be measured. The spectral confocal sensor continuously acquires and records the parameters of each measurement position of the gun barrel to be measured according to the spectral confocal principle, and continuously outputs the recorded data to the controller;

[0022] Step 60: The controller compares the parameters recorded by the spectral confocal sensor with the standard parameters in real time. When the spectral confocal sensor moves to the last measurement position and acquires the parameters, the measurement of the gun barrel ends, and the measurement result is obtained;

[0023] Step 70: The rotary table stops working, and the driving device drives the probe seat to displace along the linear guide rail, driving the spectral confocal sensor back to the initial position;

[0024] Step 80: The connecting block drives the upper fixture to move upwards, removes the measured gun barrel, and the measurement ends.

[0025] The beneficial effects of the present invention are as follows:

[0026] 1. This measuring machine positions the gun barrel through the positioning and rotating device, drives the gun barrel to rotate at the same time, drives the displacement of the sensor mounting component through the Z-direction moving device, and measures the inner bore size of the gun barrel through the spectral confocal sensor. Each component cooperates with each other to achieve efficient and rapid measurement;

[0027] 2. The upper fixture includes several forms and can be matched according to the model of the gun barrel to meet the clamping requirements;

[0028] 3. The Z-direction moving device can achieve displacement, and the sensor mounting assembly can adjust its length according to requirements. The combination of the two can be adjusted according to the diameter of the gun barrel to meet the measurement requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic structural diagram of the present invention;

[0030] Figure 2 is a schematic structural diagram of the gantry frame of the present invention;

[0031] Figure 3 is a schematic structural diagram of the positioning and rotating device of the present invention;

[0032] Figure 4 is a schematic structural diagram of the upper fixture of the present invention;

[0033] Figure 5 is a schematic structural diagram of the upper fixture of the present invention;

[0034] Figure 6 is a schematic structural diagram of the upper fixture of the present invention;

[0035] Figure 7 is a schematic structural diagram of the upper fixture of the present invention;

[0036] Figure 8 is a schematic structural diagram of the Z-direction moving device of the present invention;

[0037] Figure 9 is a schematic structural diagram of the sensor mounting assembly of the present invention;

[0038] Figure 10 is a schematic connection diagram of the spectral confocal sensor and the controller of the present invention;

[0039] In the figure: 1. Gantry frame; 2. Positioning and rotating device; 3. Z-direction moving device; 4. Sensor mounting assembly; 5. Gun barrel; 6. Spectral confocal sensor; 7. Controller; 8. Optical fiber; 11. Carriage; 12. Column; 13. Cross beam; 21. Positioning column; 22. Turntable; 23. Connecting block; 24. Upper fixture; 25. Lower fixture; 241. Fixture body; 242. Fixture through hole; 243. Axial through groove; 244. Fixed block; 245. Radial through groove; 31. Guide rail base; 32. Linear guide rail; 33. Probe seat; 34. Driving device; 41. Extension rod. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0041] Embodiment 1

[0042] As Figure 1 and Figure 10As shown in the figure, a measuring machine for the inner diameter of a gun barrel includes a gantry frame 1, a spectral confocal sensor 6, and a controller 7. On one side of the gantry frame 1, there is a positioning and rotating device 2 for fixing the gun barrel 5 to be measured and driving the gun barrel 5 to rotate. At a position near the top of the gantry frame 1 and corresponding to the positioning and rotating device 2, there is a Z-direction moving device 3 that moves along the Z-axis. On the side of the Z-direction moving device 3 and corresponding to the positioning and rotating device 2, there is a sensor mounting assembly 4 that moves along the Z-axis. The spectral confocal sensor 6 is arranged on the sensor mounting assembly 4, and the spectral confocal sensor 6 is connected to the controller 7 through an optical fiber 8.

[0043] Example 2

[0044] As Figure 2 shown in the figure, on the basis of the above embodiment, the gantry frame 1 includes a load platform 11. On the upper surface of the load platform 11, two columns 12 are symmetrically arranged, and a cross beam 13 is arranged at the tops of the two columns 12.

[0045] Example 3

[0046] As Figure 3 shown in the figure, on the basis of the above embodiment, the positioning and rotating device 2 includes a positioning column 21 arranged on the upper surface of the load platform 11 and a turntable 22 arranged on the top of the load platform 11 and on one side of the positioning column 21. On one side of the positioning column 21 close to the turntable 22, an upper clamp 24 for fixing the upper end face of the gun barrel 5 to be measured is provided through a connecting block 23. The connecting block 23 is displaced along the Z-axis relative to the positioning column 21, and a lower clamp 25 for fixing the lower end face of the gun barrel 5 to be measured is arranged on the turntable 22.

[0047] Example 4

[0048] As Figure 4 and Figure 5 shown in the figure, on the basis of the above embodiment, the upper clamp 24 includes a clamp body 241. Inside the clamp body 241, there is a clamp through hole 242 for fixing the upper end face of the gun barrel 5 to be measured and allowing the sensor mounting assembly 4 to pass through.

[0049] Example 5

[0050] As Figure 6 and Figure 7 shown in the figure, on the basis of the above embodiment, at one end face of the clamp body 241, several axial through grooves 243 extending along the axial direction to the middle of the clamp body 241 are opened around its axis. The several axial through grooves 243 divide the clamp body 241 into several fixing blocks 244. Radial through grooves 245 are opened at one ends of the several axial through grooves 243 far from the end face of the clamp body 241.

[0051] Example 6

[0052] As Figure 8 shown, on the basis of the above embodiments, the Z-direction moving device 3 includes a guide rail base 31 arranged on one side of the cross beam 13 close to the positioning and rotating device 2. A linear guide rail 32 extending along the Z-axis is provided on the side of the guide rail base 31 close to the positioning and rotating device 2. A probe seat 33 that is displaced along the linear guide rail 32 and is used for installing the sensor installation assembly 4 is arranged in the linear guide rail 32. A driving device 34 for driving the probe seat 33 to displace along the linear guide rail 32 is provided on the lower surface of the probe seat 33.

[0053] Embodiment 7

[0054] As Figure 9 shown, on the basis of the above embodiments, the sensor installation assembly 4 includes several mutually connected extension rods 41 arranged on the lower surface of the probe seat 33, and the spectral confocal sensor 6 is arranged on the lower surface of the lowermost extension rod 41.

[0055] The present invention also discloses a method for measuring the inner diameter size of a gun barrel, including the following steps:

[0056] Step 10: Enter the type of the gun barrel 5 and the standard parameters of each gun barrel 5 type and store them, and set the measurement positions of each gun barrel 5 type;

[0057] Step 20: Select the upper fixture 24 and the lower fixture 25 that match the model of the gun barrel 5 to be measured, place the gun barrel 5 to be measured on the lower fixture 25, and the connecting block 23 drives the upper fixture 24 to move downward to fix the gun barrel 5 to be measured;

[0058] Step 30: Select an extension rod 41 that matches the length of the gun barrel 5 to be measured, and install the spectral confocal sensor 6 on the extension rod 41;

[0059] Step 40: The rotating table 22 works to drive the gun barrel 5 to be measured to rotate, and the driving device 34 drives the probe seat 33 to displace along the linear guide rail 32, driving the spectral confocal sensor 6 to move into the gun barrel 5 to be measured;

[0060] Step 50: Select the gun barrel 5 type, the controller 7 retrieves the standard parameters corresponding to the selected gun barrel 5 type, the measurement of the gun barrel 5 starts, the driving device 34 drives the probe seat 33 to displace along the linear guide rail 32, driving the spectral confocal sensor 6 to continuously move inside the gun barrel 5 to be measured. The spectral confocal sensor 6 continuously acquires and records the parameters of each measurement position of the gun barrel 5 to be measured by using the spectral confocal principle, and continuously outputs the recorded data to the controller 7;

[0061] Step 60: The controller 7 compares in real time the parameters recorded by the spectral confocal sensor 6 with the standard parameters. When the spectral confocal sensor 6 moves to the last measurement position and acquires the parameters, the measurement of the gun barrel 5 ends, and the measurement result is obtained;

[0062] Step 70: The rotary table 22 stops working, and the driving device 34 drives the probe head seat 33 to displace along the linear guide rail 32, driving the spectral confocal sensor 6 back to the initial position;

[0063] Step 80: The connecting block 23 drives the upper fixture 24 to move upward, removes the measured gun barrel 5, and the measurement ends.

[0064] This measuring machine is used for measuring the inner diameter of the gun barrel 5, especially suitable for measuring the inner diameter of small-caliber gun barrels 5, and can also be used for measuring the inner diameter of other pipe products.

[0065] To ensure the measurement accuracy and suppress the influence of the environment on the deformation of the gantry frame 1. The entire gantry frame 1 is made of granite. The blank area in the middle formed by the carrier table 11, the columns 12 and the cross beam 13 is the workpiece positioning and placing area.

[0066] The rotary table 22 of this measuring machine is driven to rotate by a driving mechanism such as a driving motor. The driving mechanism can be set inside the carrier table 11 or externally connected, and is determined according to the actual situation. The upper fixture 24 of this measuring machine has several forms and can be selected according to the actual situation of the gun barrel 5 or pipe products, with the principle of achieving stable clamping.

[0067] The driving device 34 that drives the probe head seat 33 of this measuring machine to displace along the linear guide rail 32 can be set in several ways such as a cylinder, an electric push rod, and a pulley driving mechanism, and can be selected according to requirements.

[0068] The spectral confocal sensor 6 of this application adopts the spectral measurement principle. The probe housing is a synthetic metal such as titanium alloy to ensure its service life. Its diameter can be set according to the actual situation, preferably 4 mm, and a special prism group is built-in. It has a small shape and is suitable for accurately measuring structures such as narrow grooves. In addition to the probe for axial measurement inside it, there is also a special probe for 90-degree radial light beams, which can accurately measure the inner wall structure of the groove to the nanometer level. Its main technical parameters are shown in Table 1:

[0069] Table 1: Main technical parameters of the spectral confocal sensor

[0070] Serial number Probe diameter 0.4 1.5 1 Linear range 400um 1.5mm 2 Range starting point 1.5mm 0.9mm 3 Spot diameter 10um 20um 4 Absolute error ~0.3um 1.2um 5 Resolution 16nm 60nm 6 Weight 15g 15g 7 Allowed installation tilt angle ±8° ±5°

[0071] The controller 7 of this measuring machine is a high-precision controller and adopts spectral measurement technology. It can reach a measurement rate of 10 kHz; if an external xenon light source is used, the frequency can reach 70 kHz. During the dynamic measurement process, the new exposure management function in the CCD array enables the instrument to achieve rapid supplementary lighting when measuring a surface with large changes. The data output of the controller 7 is output through Ethernet.

[0072] The parameters of the gun barrel 5 described in this application include but are not limited to: length, outer diameter, land diameter, land height, crest diameter, crest height, and coaxiality. During the measurement process, the measurement status and measurement information can be displayed in real time. The measurement status and measurement information include but are not limited to: current time, pipe fitting type, measurement personnel, personnel type, current status of the equipment (standby, measuring, debugging, etc.), number of pipe fittings already measured, number of qualified products, number of defective products, number of different defect types, and remaining measurement time for the current pipe fitting. During the measurement process, the measurement can be ended midway, and the existing data will be retained. After the measurement is completed, the measurement report for the current day's batch can be selected and generated. At the same time, this measurement method can be embedded in the word software, with a prefabricated measurement report form, and the content will be automatically filled according to the measurement results. The operator can modify the form template and content. After the report is sorted out, the electronic version and the printed version can be selected for saving.

[0073] The spectral confocal principle (i.e., the spectral confocal method) adopted in this application is compared and analyzed with the optoelectronic method, the ray method, and the optical image method (industrial endoscope method) as shown in Table 2:

[0074] Table 2 Comparative Analysis of Each Measurement Method

[0075] In the present invention, the positioning and rotation device 2 is used to position the gun barrel 5 and drive the gun barrel 5 to rotate at the same time. The Z-direction moving device 3 drives the displacement of the sensor mounting assembly 4, and the inner diameter of the gun barrel 5 is measured by the spectral confocal sensor 6. Each component cooperates with each other to achieve efficient and rapid measurement; the upper fixture 24 includes several forms and can be matched according to the model of the gun barrel 5 to meet the clamping requirements; the Z-direction moving device 3 can achieve displacement, and the sensor mounting assembly 4 can adjust its length according to requirements. The combination of the two can be adjusted according to the diameter of the gun barrel 5 to meet the measurement requirements.

[0076] The above-described embodiments only represent the specific implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. A measuring machine for the inner diameter of a gun barrel, characterized in that It includes a gantry frame, a spectral confocal sensor and a controller. On one side of the gantry frame, there is a positioning and rotating device for fixing the barrel to be measured and driving the barrel to be measured to rotate. At a position near the top of the gantry frame and corresponding to the positioning and rotating device, there is a Z-direction moving device that moves along the Z-axis. At a position on the side of the Z-direction moving device and corresponding to the positioning and rotating device, there is a sensor mounting assembly that moves along the Z-axis. The spectral confocal sensor is arranged on the sensor mounting assembly, and the spectral confocal sensor is connected to the controller through an optical fiber; The positioning and rotating device includes a positioning column arranged on the upper surface of the carrier platform and a turntable arranged on the top of the carrier platform and on one side of the positioning column. On one side of the positioning column close to the turntable, there is an upper fixture for fixing the upper end face of the barrel to be measured through a connecting block. The connecting block displaces along the Z-axis relative to the positioning column. There is a lower fixture for fixing the lower end face of the barrel to be measured on the turntable; The upper fixture includes a fixture body. Inside the fixture body, there is a fixture through hole for fixing the upper end face of the barrel to be measured and allowing the sensor mounting assembly to pass through. At one end face of the fixture body, several axial through grooves extending along the axial direction to the middle of the fixture body are opened around its axis. The several axial through grooves divide the fixture body into several fixing blocks; The Z-direction moving device includes a guide rail base arranged on one side of the cross beam close to the positioning and rotating device. On the side of the guide rail base close to the positioning and rotating device, there is a linear guide rail extending along the Z-axis. Inside the linear guide rail, there is a probe head seat that displaces along the linear guide rail and is used for mounting the sensor mounting assembly.

2. The internal bore size measuring machine for a gun barrel according to claim 1, wherein The gantry frame includes a carrier platform. On the upper surface of the carrier platform, two columns are symmetrically arranged. At the tops of the two columns, there is a cross beam.

3. The bore size measuring machine for a gun barrel according to claim 1, wherein Radial through grooves are opened at one ends of the several axial through grooves far from the end face of the fixture body.

4. A barrel inner diameter measuring machine according to claim 1, characterized in that, A driving device for driving the probe head seat to displace along the linear guide rail is arranged on the lower surface of the probe head seat.

5. A barrel inner diameter measuring machine according to claim 4, characterized in that The sensor mounting assembly includes several interconnected extension rods arranged on the lower surface of the probe head seat. The spectral confocal sensor is arranged on the lower surface of the lowermost extension rod.

6. A method for measuring the inner diameter of a gun barrel, characterized in that, It is realized by the barrel inner diameter size measuring machine according to any one of claims 1-5, including the following steps: Step 10: Input the barrel type and the standard parameters of each barrel type and store them, and set the measurement positions of each barrel type; Step 20: Select the upper fixture and the lower fixture that match the model of the barrel to be measured, place the barrel to be measured on the lower fixture, and the connecting block drives the upper fixture to move down to fix the barrel to be measured; Step 30: Select the extension rod that matches the length of the barrel to be measured, and install the spectral confocal sensor on the extension rod; Step 40: The rotating table works to drive the barrel to be measured to rotate, and the driving device drives the probe head seat to displace along the linear guide rail to drive the spectral confocal sensor to move into the barrel to be measured; Step 50: Select the barrel type. The controller retrieves the standard parameters corresponding to the selected barrel type, and the barrel measurement begins. The driving device drives the probe head seat to displace along the linear guide rail, driving the spectral confocal sensor to continuously move inside the measured barrel. The spectral confocal sensor continuously acquires and records the parameters of each measurement position of the measured barrel using the spectral confocal principle, and continuously outputs the recorded data to the controller; Step 60: The controller compares the parameters recorded by the spectral confocal sensor with the standard parameters in real time. When the spectral confocal sensor moves to the last measurement position and acquires the parameters, the barrel measurement ends, and the measurement result is obtained; Step 70: The rotary table stops working. The driving device drives the probe head seat to displace along the linear guide rail, driving the spectral confocal sensor back to the initial position; Step 80: The connecting block drives the upper fixture to move upward, removes the measured barrel, and the measurement ends.

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