Railway wagon axle external dimension automatic measurement system and method

Abstract

The invention discloses a railway wagon axle external dimension automatic measurement system and method, and the system comprises an axle transmission line which extends in the X-axis direction, the feeding end of the axle transmission line is provided with an axle feeding and correcting mechanism, and an axle external dimension measurement work station is arranged beside the axle transmission line. The axle external dimension measuring workstation comprises a base, a lifting platform capable of moving in the Z-axis direction is arranged on the base, and two positioning roller carriers used for supporting and positioning an axle and a portal frame extending in the Y-axis direction are arranged on the lifting platform. The portal frame is provided with an on-line projection image measuring instrument and a grating ruler which can move in the Y-axis direction. The axle measurement efficiency can be greatly improved, the manual measurement cost is reduced, and the product quality consistency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of axle end threaded hole processing, and in particular relates to an automatic measurement system and method for the external dimensions of a railway freight car axle. Background Art

[0002] In the prior art, the external dimensions of axles of railway vehicles such as railway freight cars, railway locomotives, urban rails, railway passenger cars, and EMUs are measured manually, and the measurement personnel use measuring instruments such as vernier calipers and measuring rods to measure the external dimensions of the axles. The manual measurement method requires a large number of measurement personnel, which has high labor costs, and the manual measurement results are greatly affected by human factors, and the consistency of the measurement results is not high. Therefore, it is urgent to develop an automatic measurement system and method for the external dimensions of railway freight car axles to achieve flexible, automated, and efficient measurement of the external dimensions of axles. Summary of the invention

[0003] The present invention discloses a system and method for automatically measuring the external dimensions of axles of railway freight cars. The system is a flexible automatic measurement method for the external dimensions of axles of railway vehicles such as railway freight cars, railway locomotives, urban rails, railway passenger cars, and EMUs. The system can greatly improve the efficiency of axle measurement, reduce manual measurement costs, and improve product quality consistency. At the same time, the system can measure the external dimensions of axles of all models of railway vehicles, has a high degree of flexibility, and is very suitable for mass production of products.

[0004] The present invention discloses a system and method for automatically measuring the external dimensions of axles of railway freight cars. The system is a flexible automatic measurement method for the external dimensions of axles of railway vehicles such as railway freight cars, railway locomotives, urban rails, railway passenger cars, and EMUs. The system can greatly improve the efficiency of axle measurement, reduce manual measurement costs, and improve product quality consistency. At the same time, the system can measure the external dimensions of axles of all models of railway vehicles, has a high degree of flexibility, and is very suitable for mass production of products.

[0005] The invention discloses an automatic measurement system for the external dimensions of axles of railway freight cars, comprising an axle transmission line extending along the X-axis, an axle feeding and correction mechanism being arranged at the feeding end of the axle transmission line, an axle appearance dimension measurement workstation being arranged beside the axle transmission line, the axle appearance dimension measurement workstation comprising a base, a lifting platform which can be displaced along the Z-axis on the base, two positioning roller frames for supporting and positioning the axles and a gantry extending along the Y-axis being arranged on the lifting platform, and an online projection image measuring instrument and a grating ruler which can be displaced along the Y-axis being arranged on the gantry.

[0006] In a preferred embodiment of the present invention, the axle feeding and correction mechanism includes a fixed frame, a slideway arranged obliquely along the X-axis direction is provided on the fixed frame, an axle limiting mechanism capable of limiting the axle along the X-axis direction is provided in the middle of the slideway, a baffle is provided at the end of the slideway, a lifting and feeding mechanism capable of lifting the axle along the Z-axis direction and a horizontal correction mechanism for adjusting the Y-axis position of the axle are provided at the end of the slideway.

[0007] In a preferred embodiment of the present invention, the lifting and loading mechanism is a scissor fork lift.

[0008] In a preferred embodiment of the present invention, the horizontal correction mechanism includes a gantry arranged on the fixed frame, and the gantry is provided with a pair of jaws that can be displaced along the Y-axis direction and a power source for driving the jaws to displace along the Y-axis direction.

[0009] In a preferred embodiment of the present invention, the power source is a cylinder.

[0010] In a preferred embodiment of the present invention, the clamping claw comprises a slide connected to the gantry and a clamping arm for clamping the axle, and the clamping arm is provided with a positioning annular boss corresponding to the shape of the axle.

[0011] In a preferred embodiment of the present invention, the axle limiting mechanism comprises a rotating shaft which can rotate synchronously along the Y-axis, at least two discs are arranged on the rotating shaft, and each disc is provided with a notch for limiting the axle along the X-axis.

[0012] In a preferred embodiment of the present invention, the notch is a fan-shaped notch.

[0013] The present invention also discloses a method for using an automatic measurement system for the external dimensions of axles of railway freight cars. The axle is corrected in the Y-axis direction by an axle loading and correction mechanism, and then lifted and loaded along the Z-axis direction to an axle transmission line. The axle transmission line transports the axle upward and automatically transmits it to an axle appearance dimension measurement workstation. The external dimensions of the axle are automatically detected by carrying an online projection image measuring instrument and a grating ruler via a linear guide rail.

[0014] In a preferred embodiment of the present invention, the axle to be inspected is rolled to the notch of the rotating disc through the slideway of the axle feeding and correction mechanism for blocking and positioning; the two rotating discs rotate clockwise to roll the axle to a horizontal correction position; the horizontal correction mechanism works to correct the Y-axis position of the axle, and after the correction is completed, the horizontal correction mechanism is separated from the axle, and the jacking feeding mechanism lifts the axle upward and drops it on the axle transmission line; the axle transmission line automatically transmits the axle to be inspected to the axle appearance dimension measurement workstation; the lifting and lowering of the axle appearance dimension measurement workstation The platform lifts the axle upwards, and the axle is clamped on the positioning roller frame and synchronously rises to the measuring height and is fixed; the gantry is equipped with an online projection image measuring instrument and a grating ruler that automatically moves from the outside of one end of the axle to the outside of the other end, and synchronously measures the length, diameter and other external dimensions of the axle; the positioning roller frame rotates 90 degrees clockwise and then is fixed, and the linear guide automatically returns to its original position from the other end, and the external dimensions of the axle are synchronously measured again; after measuring the outside, the lifting platform descends and places the axle on the axle transmission line; the axle is automatically transmitted to the next process through the axle transmission line.

[0015] The beneficial effects of the present invention are as follows: First, the present invention realizes the automated measurement of the external dimensions of the axle, greatly improving the measurement efficiency. Compared with the traditional manual measurement method, the present system can quickly and accurately complete the dimensional measurement of a large number of axles, greatly reducing the measurement time and labor costs. Secondly, the present system adopts advanced online projection image measuring instrument and grating ruler technology, which significantly improves the measurement accuracy and consistency. This not only eliminates the errors caused by human factors, but also ensures the reliability and stability of the measurement results, thereby improving the consistency of product quality. Third, the present invention has a high degree of flexibility and can adapt to various types of railway vehicle axles, including railway freight cars, railway locomotives, urban rails, railway passenger cars and EMUs. This versatility enables the system to flexibly respond to the measurement requirements of different types of axles, which is very suitable for large-scale production environments. Fourth, the automated measurement system of the present invention integrates multiple functional modules such as axle loading, correction, transmission and measurement, realizing the automation of the entire process from loading to measurement. This integrated design not only simplifies the operation process, but also further improves the overall production efficiency. Finally, the design of the present invention fully considers the special requirements of axle measurement, such as Y-axis position correction, multi-angle measurement, etc., to ensure the comprehensiveness and accuracy of the measurement. This is of great significance for ensuring the safety and reliability of railway vehicles. In summary, the automatic measurement system and method for the external dimensions of railway freight car axles of the present invention not only solves the problems of low efficiency, high cost, poor consistency, etc. of traditional manual measurement methods, but also provides an advanced and efficient quality control method for the railway vehicle manufacturing industry through its high degree of automation, flexibility and precision, which has important practical application value for improving production efficiency and product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments disclosed in the present invention, the drawings of the embodiments will be briefly introduced below. These drawings are only used for illustrative purposes and are not intended to limit the protection scope of the present invention.

[0017] Figure 1 It is a front view schematic diagram of the present invention;

[0018] Figure 2 It is a top view schematic diagram of the present invention;

[0019] Figure 3 It is a schematic diagram of the present invention;

[0020] Figure 4 It is a schematic diagram of the axle feeding and correction mechanism of the present invention;

[0021] Figure 5 It is a front view schematic diagram of the axle feeding and correction mechanism of the present invention;

[0022] Figure 6 It is a side view schematic diagram of the axle feeding and correction mechanism of the present invention;

[0023] Figure 7 It is a three-dimensional schematic diagram of the axle appearance dimension measurement workstation of the present invention;

[0024] Figure 8 It is a schematic diagram of the main view of the axle appearance dimension measurement workstation of the present invention;

[0025] Fig. 9 It is a schematic side view of the axle appearance dimension measurement workstation of the present invention;

[0026] Fig.10 It is a top view schematic diagram of the axle appearance dimension measurement workstation of the present invention;

[0027] Fig.11 It is a schematic front view of the axle to be tested of the present invention;

[0028] Fig.12 It is a schematic side view of the axle to be tested of the present invention;

[0029] Fig.13 The workflow of the present invention is shown in FIG. Figure 1 ;

[0030] Fig.14 The workflow of the present invention is shown in FIG. Figure 2 ;

[0031] Fig.15 The workflow of the present invention is shown in FIG. Figure 3 ;

[0032] Fig.16 The workflow of the present invention is shown in FIG. Figure 4 . DETAILED DESCRIPTION

[0033] The technical solution of the present invention (including the preferred technical solution) is further described in detail below by means of the accompanying drawings and by listing some optional embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] like Figures 1 to 16 As shown, this embodiment discloses an automatic measurement system for the external dimensions of axles of railway freight cars. The system mainly consists of an axle feeding and correction mechanism, an axle transmission line, an axle external dimension measurement workstation, etc. Figure 1 These three parts work together to achieve automated and efficient measurement of the external dimensions of the axle.

[0035] The axle feeding and correction mechanism is mainly responsible for automatically sliding the axle from the storage area to the correction position, and correcting the axle axial horizontally through the correction mechanism. The axle transmission line is an automatic flow mechanism for the axle, which is mainly responsible for the axle entering the measurement actuator for measurement, and automatically transferring the axle to the next process after measurement. The axle appearance dimension measurement workstation is mainly responsible for the automatic measurement of the axle's external dimensions such as the axle length and the diameter of each part.

[0036] The axle transmission line 1 is an important part of the whole system, and it is arranged along the X-axis. This arrangement ensures that the axle can move smoothly along the predetermined path, laying the foundation for subsequent measurement work. The feeding end of the axle transmission line 1 is connected to the axle feeding and correction mechanism 3. This design enables the axle to be properly adjusted and positioned before entering the transmission line.

[0037] The axle appearance dimension measurement workstation 2 is the core part of this system, which is set up next to the axle transmission line 1. The design of this workstation reflects the innovation and efficiency of this system. The basis of the workstation is a base 21, which provides a stable support for the entire measurement system. On the base 21, a lifting platform 22 that can be displaced along the Z axis is set. The design of this lifting platform allows the system to be adjusted according to the height of different axles to ensure the accuracy of the measurement.

[0038] Two key components are set on the lifting platform 22: a positioning roller frame 23 and a gantry 24. The main function of the positioning roller frame 23 is to support and position the axle. By using two positioning roller frames, the system can stably support the axle and ensure that the axle maintains the correct position during the measurement process. This design not only improves the accuracy of the measurement, but also increases the safety of the entire process. The gantry 24 is arranged to extend along the Y-axis, and this arrangement provides a moving track for the measuring equipment. On the gantry 24, two key measuring devices are set: an online projection image measuring instrument 26 and a grating ruler 25. Both devices can be displaced along the Y-axis, which means that they can move along the length of the axle, thereby realizing the measurement of the entire length of the axle.

[0039] The online projection image measuring instrument 26 is an advanced optical measuring device that can quickly and accurately capture the external dimensions of the axle through projection technology. This non-contact measurement method not only increases the speed of measurement, but also avoids any potential damage to the axle surface. The grating ruler 25 is a high-precision linear measurement tool that can accurately measure the length and other linear dimensions of the axle. By combining these two measuring devices, the system can comprehensively and accurately obtain the external dimension data of the axle.

[0040] The axle feeding and correction mechanism 3 is the key link to ensure the smooth progress of the entire measurement process. The design of this mechanism fully considers the characteristics of the axle and the measurement requirements, and contains multiple carefully designed components. It is mainly composed of a slide, an axle positioning mechanism, a jacking and feeding mechanism, a horizontal correction mechanism, a bearing mechanism and other parts. First of all, the entire mechanism is built on a fixed frame 31, which provides stable support for subsequent components. On the fixed frame 31, a slide 32 is arranged tilted along the X-axis. This inclined design cleverly utilizes gravity, allowing the axle to roll naturally to the specified position, thereby simplifying the feeding process. The slide can slide the axle from the storage area to the side of the axle positioning mechanism. The inclination angle of the slide is 15 degrees, ensuring that the axle can roll freely from top to bottom.

[0041] In the middle of the slide 32, an axle limiting mechanism 33 is set. This mechanism can limit the axle along the X-axis to ensure that the axle will not move accidentally during the loading process. The core part of the axle limiting mechanism 33 is a rotating shaft 331 that can rotate synchronously along the Y-axis. On this rotating shaft, at least two discs 332 are set. Each disc 332 has a specially designed notch, which is used to limit the axle along the X-axis. It is worth noting that this notch adopts a fan-shaped design, which can better adapt to the cylindrical shape of the axle and provide a more stable limiting effect. The axle positioning mechanism consists of a hydraulic cylinder and two rotating discs. The two rotating discs are controlled by the hydraulic cylinder to rotate 110 degrees clockwise and counterclockwise. When rotating 110 degrees clockwise, the axle rolls to the horizontal correction position, and then rotates 110 degrees counterclockwise to position the next axle at the rotating disc notch position.

[0042] At the end of the slide 32, a baffle 34 is provided. The function of this baffle is to prevent the axle from exceeding the predetermined position during the rolling process, which is a simple and effective safety design. Two key mechanisms are provided adjacent to the baffle 34: a lifting and feeding mechanism 35 and a horizontal correction mechanism 36. The lifting and feeding mechanism 35 can lift the axle along the Z axis and lift the axle from the slide to the height of the transmission line. In this embodiment, the lifting and feeding mechanism 35 adopts the design of a scissor fork lift truck. This design is not only simple in structure and easy to operate, but also provides a stable lifting action to ensure that the axle will not shake or tilt during the lifting process. The lifting and feeding mechanism is equipped with a V-block. During the lifting process, the position and angle of the axle will not change. The lifting and feeding mechanism transports the axle to the axle chain conveyor line and puts the axle down.

[0043] The main function of the horizontal correction mechanism 36 is to adjust the Y-axis position of the axle to ensure that the axle is in the correct position before entering the measuring workstation. This mechanism includes a second gantry 361 arranged on the fixed frame 31. On the second gantry 361, a pair of clamps 362 that can be displaced along the Y-axis are arranged. This pair of clamps can accurately grasp and move the axle to achieve Y-axis position adjustment. In order to drive the clamps 362 to displace along the Y-axis, the horizontal correction mechanism 36 is also equipped with a power source 363. In this embodiment, this power source uses a cylinder. The selection of the cylinder takes into account its fast response speed and high control accuracy, and can meet the needs of precise adjustment of the axle position. The hydraulic cylinder of the horizontal correction mechanism drives the clamp to clamp the end faces on both sides of the axle to correct the axle horizontally.

[0044] The design of the clamping jaw 362 has also been carefully considered. It includes a portion connected to the slide of the second gantry 361 and a clamping arm for directly clamping the axle. A positioning annular boss corresponding to the shape of the axle is provided on the clamping arm. This design can ensure that the clamping jaw forms a good fit with the axle when grabbing the axle, thereby improving the stability and accuracy of the clamping.

[0045] The bearing mechanism serves as the load-bearing frame of the entire feeding mechanism, and is used to bear the slideway, axle positioning mechanism, horizontal correction mechanism and axle, and has certain rigidity and strength.

[0046] The axle appearance dimension measurement workstation is mainly composed of gantry mechanism, grating ruler, online projection image measuring instrument, linear guide, positioning roller frame, lifting mechanism, etc. As a bearing mechanism for grating ruler, online projection image measuring instrument, linear guide and other components, the gantry mechanism has a certain rigidity and strength, and is fixed to the ground with anchor bolts to ensure the stability and reliability of the entire mechanism.

[0047] The grating ruler is used to measure and record the length of the axle, and the measuring range is larger than the axle length. The online projection image measuring instrument is used to measure the diameter and outer contour of various parts of the axle. It adopts the through-beam measurement, which is not affected by ambient light, and can suppress the deformation of the lens and special algorithm processing. It can realize automatic measurement without correction, and the measurement accuracy is ±0.2μm, which meets the millimeter-level measurement requirements of the axle.

[0048] The linear guide rail carries measuring instruments such as grating rulers and online projection image measuring instruments and moves automatically and stably from one end of the axle to the other end, and synchronously measures the length, diameter and other external dimensions of the axle during the movement. The positioning roller frame is used to support the axle to be tested. After the online projection image measuring instrument moves from one end of the axle to the other end, the positioning roller frame rotates 90 degrees, and the online projection image measuring instrument moves back to its original position from the other end with the linear guide rail. During the movement, the external dimensions of the axle are measured again synchronously. If both measurement results are qualified, the axle passes this inspection process.

[0049] The lifting mechanism carries the positioning roller frame. When the axle transmission line transfers the axle to the positioning roller frame position, the lifting mechanism rises, lifts the wheel to the inspection height and fixes it. After the axle inspection is completed, it descends and places the wheel back in the V-groove of the axle transmission line for transportation to the next process.

[0050] like Figures 13-16As shown in the figure, the working process of the automatic measurement system for the external dimensions of railway freight car axles is as follows: the axle to be inspected is rolled to the notch of the rotating disc through the slideway of the axle feeding and correction mechanism for blocking and positioning → the two rotating discs are rotated 110 degrees clockwise to roll the axle to the horizontal correction position → the hydraulic cylinder of the horizontal correction mechanism drives the clamping plate to clamp the end faces of both sides of the axle for horizontal correction → the clamping plate is released, and the jacking feeding mechanism lifts the axle upward and falls into the V-groove of the axle transmission line for clamping → the axle transmission line automatically transmits the axle to be inspected to the appearance dimension measurement position → the lifting mechanism of the axle appearance dimension measurement workstation lifts the axle upward, and the axle is clamped on the positioning roller frame and synchronously rises to the measurement height and is fixed, see the attached figure. Fig.13 →The linear guide rail carries the online projection image measuring instrument and grating ruler and automatically moves from the outside of the axle end to the outside of the other end, and synchronously measures the length, diameter and other external dimensions of the axle. See attached. Fig.14 →Rotate the positioning roller frame 90 degrees clockwise and fix it. The linear guide automatically returns to its original position from the other end. Measure the external dimensions of the axle again. See attached. Fig.15 →After measuring the outside, the lifting mechanism descends and places the axle into the V-groove of the axle transmission line →The axle is automatically transferred to the next process through the axle transmission rack, see attached Fig.16 .

[0051] This automated measurement system not only greatly improves measurement efficiency, but also significantly improves measurement accuracy. By reducing manual operations, the system reduces measurement errors and ensures the consistency and reliability of measurement results. In addition, the system is designed with high flexibility and can adapt to axles of different models and sizes to meet diverse measurement needs.

[0052] This system has a reasonable structure, high stability, reliability, safety and durability, simple operation, convenient maintenance, and runs smoothly under the condition of continuous operation for 22 hours under rated load. The appearance meets the requirements of GB 2893. For the noise test of this system, the equipment noise at 1m away from the equipment is less than 85dB; other conditions meet the provisions of GBZ 1. Reliable anti-loosening measures and anti-overcurrent measures are set for the connection of all moving and running parts of this system.

[0053] The steps of using the present invention are as follows: the axle to be inspected is rolled to the notch of the rotating disc 332 through the slideway of the axle feeding and correction mechanism 3 to be blocked and positioned; the two rotating discs 332 rotate clockwise to roll the axle to a horizontal correction position; the horizontal correction mechanism 36 works to correct the Y-axis position of the axle, and after the correction is completed, the horizontal correction mechanism 36 is separated from the axle, and the lifting and feeding mechanism 35 lifts the axle upward and drops it on the axle transmission line 1; the axle transmission line 1 automatically transmits the axle to be inspected to the axle appearance dimension measurement workstation 2; the lifting and lowering level of the axle appearance dimension measurement workstation 2 The platform 22 lifts the axle upward, and the axle is clamped on the positioning roller frame 23 and synchronously rises to the measuring height and is fixed; the gantry 24 is provided with an online projection image measuring instrument 26 and a grating ruler 25 which automatically move from the outside of the axle end to the outside of the other end, and synchronously measure the length, diameter and other external dimensions of the axle; the positioning roller frame 23 is rotated 90 degrees clockwise and then fixed, and the linear guide automatically returns to the original position from the other end, and the external dimensions of the axle are synchronously measured again; after measuring the outside, the lifting platform 22 descends and drops the axle on the axle transmission line 1; the axle is automatically transmitted to the next process through the axle transmission line 1.

[0054] The automatic measurement system for the external dimensions of railway freight car axles of the present invention represents an important advancement in axle inspection technology. It not only improves production efficiency, but also makes an important contribution to ensuring the safety of railway transportation. With the widespread application of this technology, we can expect that the quality of railway vehicle manufacturing and maintenance will be further improved.

[0055] Those skilled in the art will readily appreciate that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, combinations, replacements, improvements, etc. made within the spirit and principles of the present invention are included within the protection scope of the present invention.

Claims

1. An automatic measurement system for the external dimensions of axles of railway freight cars, comprising an axle transmission line extending along the X-axis direction, characterized in that: An axle loading and correction mechanism is provided at the feeding end of the axle transmission line, an axle appearance dimension measurement workstation is provided next to the axle transmission line, and the axle appearance dimension measurement workstation includes a base, a lifting platform which can be displaced along the Z axis on the base, two positioning roller frames for supporting and positioning the axle and a gantry extending along the Y axis are provided on the lifting platform, and an online projection image measuring instrument and a grating ruler which can be displaced along the Y axis are provided on the gantry.

2. The automatic measurement system for external dimensions of railway freight car axles according to claim 1 is characterized in that: The axle feeding and correction mechanism includes a fixed frame, a slideway arranged obliquely along the X-axis is provided on the fixed frame, an axle limiting mechanism capable of limiting the axle along the X-axis is provided in the middle of the slideway, a baffle is provided at the end of the slideway, a lifting and feeding mechanism capable of lifting the axle along the Z-axis and a horizontal correction mechanism for adjusting the Y-axis position of the axle are provided at the end of the slideway.

3. The automatic measurement system for external dimensions of railway freight car axles according to claim 2 is characterized in that: The lifting and loading mechanism is a scissor fork lifting vehicle.

4. The automatic measurement system for external dimensions of railway freight car axles according to claim 2 is characterized in that: The horizontal correction mechanism includes a second gantry arranged on the fixed frame, and the second gantry is provided with a pair of clamping jaws that can be displaced along the Y-axis direction and a power source for driving the clamping jaws to be displaced along the Y-axis direction.

5. The automatic measurement system for external dimensions of railway freight car axles according to claim 4 is characterized in that: The power source is a cylinder.

6. The automatic measurement system for external dimensions of railway freight car axles according to claim 4, characterized in that: The clamping claw comprises a slide table connected to the second gantry and a clamping arm for clamping the axle, and the clamping arm is provided with a positioning annular boss corresponding to the shape of the axle.

7. The automatic measurement system for external dimensions of railway freight car axles according to claim 2, characterized in that: The axle limiting mechanism comprises a rotating shaft which can rotate synchronously along the Y axis, at least two discs are arranged on the rotating shaft, and each disc is provided with a notch for limiting the axle along the X axis.

8. The automatic measurement system for external dimensions of railway freight car axles according to claim 7, characterized in that: The notch is a fan-shaped notch.

9. A method for using the automatic measurement system for external dimensions of axles of railway freight cars according to any one of claims 1 to 8, characterized in that: The axle is corrected in the Y-axis direction by using the axle loading and correction mechanism, and then lifted and loaded along the Z-axis direction to the axle transmission line. The axle transmission line transports the axle upward and automatically transmits it to the axle appearance dimension measurement workstation. The linear guide rail carries an online projection image measuring instrument and a grating ruler to automatically detect the external dimensions of the axle.

10. The method for using the automatic measurement system for external dimensions of railway freight car axles according to claim 9, characterized in that: The axle to be inspected is rolled to the notch of the rotating disc through the slideway of the axle feeding and correction mechanism for blocking and positioning; the two rotating discs rotate clockwise to roll the axle to the horizontal correction position; the horizontal correction mechanism works to correct the Y-axis position of the axle. After the correction is completed, the horizontal correction mechanism is separated from the axle, and the jacking feeding mechanism lifts the axle upward and drops it on the axle transmission line; the axle transmission line automatically transmits the axle to be inspected to the axle appearance dimension measurement workstation; the lifting platform of the axle appearance dimension measurement workstation lifts the axle upward, and the axle is clamped on the positioning roller frame and synchronously rises to the measuring height and is fixed; the gantry is equipped with an online projection image measuring instrument and a grating ruler that automatically moves from the outside of the axle end to the outside of the other end, and synchronously measures the length, diameter and other external dimensions of the axle; the positioning roller frame rotates 90 degrees clockwise and is fixed, and the linear guide automatically returns to the original position from the other end, and the external dimensions of the axle are synchronously measured again; after measuring the outside, the lifting platform descends and drops the axle on the axle transmission line; the axle is automatically transmitted to the next process through the axle transmission line.

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