A magnetic positioning tool for processing the heel end of a frog

Abstract

The utility model discloses a magnetic positioning tool for the processing of the tail end of a forged and pressed point rail, comprising a workbench, two rows of magnetic bases arranged symmetrically, a profiling module and a support plate. The inner end face of the profiling module is provided with a profiling curved surface that cooperates with the rail waist arc surface of the point rail. The upper and lower sides of the profiling curved surface are provided with profiling inclined surfaces that respectively adhere to the rail head and rail bottom inclined surfaces, forming a "curved surface + double inclined surface" three-point close adhesion positioning system. The magnetic base is internally provided with a strong magnetic unit and externally coated with a non-magnetic isolation layer to reduce magnetic leakage. A magnetic switch is connected to the outer side of the magnetic base to control the on-off of the magnetic circuit. The profiling module is made of non-magnetic 7075 aluminum alloy to avoid magnetic circuit short circuit problems and is detachably connected to the magnetic base through bolts and pins. The contact area of the tool is not less than 400% higher than that of traditional tools, the adsorption force is increased by more than 3 times, vibration is effectively suppressed, the processing precision and stability are significantly improved, and the profiling module can be replaced to adapt to different rail types, with strong versatility.

Description

Technical Field

[0001] This utility model relates to the technical field of rail transit equipment manufacturing, specifically to a magnetic positioning tool for processing the heel end of forged rail tips. Background Technology

[0002] In the field of rail transit equipment manufacturing, turnout switch rails are key components for train steering, and their machining accuracy directly affects the safety and smoothness of track operation. After the switch rails are forged at the heel end, they need to be precision milled on a CNC milling machine to ensure that their geometric contours and assembly dimensions meet the design requirements.

[0003] However, due to the significant structural features of the forged rail tip, there is a difference in rail shape between the base material and the forming section (such as a height difference of up to 30 mm between the rail base and the rail web), and the rail web is a composite arc surface, which also includes a complex transition structure of the "upper jaw slope" on the rail head side and the "lower jaw slope" on the rail base side, which poses a serious challenge to traditional magnetic tooling during the clamping process.

[0004] In existing technologies, commonly used planar magnetic chucks can only form line contact with the curved surface of the pointed rail, with the actual effective contact area being less than 15% of the theoretical contact area, resulting in a reduction in magnetic conduction efficiency of more than 60%. In addition, due to poor contact rigidity, the workpiece vibration amplitude during processing is as high as 0.2 mm or more, which not only leads to abnormal tool wear (increasing the wear rate by 80%), but also seriously affects the surface roughness and dimensional accuracy of the machined surface, and may even cause safety hazards such as workpiece loosening or flying out.

[0005] Therefore, there is an urgent need for a specialized tooling that can achieve high-precision and high-stability clamping to solve problems such as poor contact, weak adsorption force, and large vibration in existing technologies. Although some contouring fixtures have been applied to the processing of special parts, there is still no technical solution that combines the "curved surface + inclined surface" composite contouring structure with magnetic positioning and is specifically optimized for the complex geometric features of the forged rail tip. Utility Model Content

[0006] The purpose of this invention is to provide a magnetic positioning fixture for machining the heel end of forged point rails, so as to solve the above-mentioned defects caused by the prior art.

[0007] A magnetic positioning fixture for machining the heel end of a forged point rail includes: Workbench; Two rows of magnetic bases are symmetrically arranged on the upper side of the workbench, and a row of contouring modules are connected to the inner side of each magnetic base at intervals; The inner end face of the contouring module is provided with a contouring curved surface that matches the rail waist arc surface at the heel end of the tip rail. The contoured curved surface is provided with contoured inclined surfaces on its upper and lower sides, and the two contoured inclined surfaces are respectively matched with the rail head inclined surface and rail bottom inclined surface at the heel end of the switch rail. Each row of contouring modules has a support plate underneath, which is horizontally mounted on the upper side of the workbench.

[0008] Preferably, the magnetic base has a strong magnetic unit inside, is covered with a non-magnetic isolation layer on the outside, and is rotatably connected to a magnetic switch on its outside.

[0009] Preferably, the contouring module is detachably connected to the inner side of the magnetic base by locking bolts and positioning pins.

[0010] Preferably, the contouring module is made of non-magnetic aluminum alloy with a thickness of 10mm.

[0011] Preferably, the radius of curvature error of the contoured surface does not exceed ±0.5mm, and it is optimized by finite element analysis to ensure uniform magnetic force distribution.

[0012] Preferably, a photoelectric switch is connected to the inner side of the magnetic base via a sensor bracket.

[0013] Preferably, a vibration sensor is fixedly connected to the bottom surface of the support plate.

[0014] Compared with the prior art, the present invention has the following advantages: 1. Significantly enhanced clamping stability: The composite structure of "contour curved surface + contour inclined surface" forms a three-point close-fitting positioning with the switch rail, increasing the contact area by more than 400%, which greatly improves the clamping rigidity and effectively prevents displacement and vibration during the processing.

[0015] 2. Significantly improved magnetic efficiency: The contour module is made of non-magnetic 7075 aluminum alloy and designed with a non-magnetic isolation layer to effectively block the short-circuit path of magnetic force, so that the magnetic lines of force are concentrated on the contact area of ​​the workpiece, the magnetic force transmission efficiency is increased by more than 60%, and the leakage magnetic rate is controlled below 8%.

[0016] 3. Significantly improved machining quality: The vibration amplitude of the workpiece is reduced from more than 0.2 mm in traditional tooling to less than 0.05 mm, significantly reducing tool wear (wear rate reduced by 80%), improving the surface roughness grade of the machined surface, and ensuring dimensional consistency.

[0017] 4. High adaptability and versatility: The modular design supports rapid changeover of different rail types. Only the corresponding contouring module needs to be replaced to adapt to various point rail specifications, making it suitable for mass production and flexible manufacturing scenarios.

[0018] 5. High level of intelligence: It integrates photoelectric switches and vibration sensors to realize workpiece positioning detection and real-time monitoring of processing status, and supports linkage with CNC systems to improve the level of automation. Attached Figure Description

[0019] Figure 1 This is a three-dimensional structural diagram of the present invention.

[0020] Figure 2 This is a schematic diagram of the overall front view of this utility model.

[0021] Figure 3 This is a structural diagram of the overall positioning section from a first-person perspective.

[0022] Figure 4 This is a structural diagram of the overall second-person perspective of the positioning section.

[0023] Figure 5 A schematic diagram of the structure used to locate the localized explosion.

[0024] Figure 6 A structural diagram from a first-person perspective, supporting the overall structure.

[0025] Figure 7 A structural diagram from a second-view perspective to support the overall structure.

[0026] Figure 8 This is a schematic diagram of the structure for the conformal module to mate with the heel end of the switch rail.

[0027] Figure 9 This is a schematic diagram of the structure of the old and new magnetic positioning fixtures.

[0028] in: 10-Workbench; 11-Magnetic base; 11a-Magnetic switch; 12-Following module; 12a-Following curved surface; 12b-Following inclined surface; 13-Locking bolt; 14-Positioning pin; 15-Photoelectric switch; 16-Sensor bracket; 17-Support plate; 18-Vibration sensor; 20-Point rail; 20a-Waist arc surface; 20b-Rail head ramp surface; 20c-Rail bottom ramp surface. Detailed Implementation

[0029] To make the technical means, creative features, objectives and effects of this utility model easier to understand, the present utility model will be further described below in conjunction with specific embodiments.

[0030] like Figures 1 to 8 As shown, a magnetic positioning fixture for machining the heel end of a forged point rail includes: Workbench 10; Two rows of magnetic bases 11 are symmetrically arranged on the upper side of the workbench 10, and a row of contouring modules 12 are connected to the inner side of each magnetic base 11 at intervals. The inner end face of the contouring module 12 is provided with a contouring curved surface 12a that matches the rail waist arc surface 20a at the heel end of the tip rail 20. The contoured curved surface 12a is provided with contoured inclined surfaces 12b on its upper and lower sides respectively. The two contoured inclined surfaces 12b are respectively matched with the rail head inclined surface 20b and the rail bottom inclined surface 20c at the heel end of the switch rail 20. Each row of contouring modules 12 is provided with a support plate 17 below it, and the support plate 17 is horizontally installed on the upper side of the workbench 10.

[0031] In this embodiment, the magnetic base 11 has a strong magnetic unit inside and is covered with a non-magnetic isolation layer on the outside, and a magnetic switch 11a is rotatably connected to its outer side. The operator can control the on / off of the magnetic circuit by rotating the magnetic switch 11a to achieve quick clamping and release.

[0032] In this embodiment, the contouring module 12 is detachably connected to the inner side of the magnetic base 11 via locking bolts 13 and positioning pins 14. The positioning pins 14 ensure a repeatability accuracy of ≤0.1mm.

[0033] In this embodiment, the contouring module 12 is made of non-magnetic 7075 aluminum alloy with a thickness of 10mm. This design ensures sufficient structural strength while avoiding magnetic short circuits caused by magnetic conductivity.

[0034] In this embodiment, the radius of curvature error of the contoured surface 12a does not exceed ±0.5mm, and it has been optimized through finite element analysis to ensure uniform magnetic force distribution. This design ensures high-precision surface contact with the switch rail 20 and the end rail waist arc surface 20a.

[0035] In this embodiment, a photoelectric switch 15 is connected to the inner side of the magnetic base 11 via a sensor bracket 16. The photoelectric switch 15 is used to detect in real time whether the switch rail 20 is accurately placed in position and outputs a position signal to the control system to realize intelligent judgment of the clamping status.

[0036] In this embodiment, a vibration sensor 18 is fixedly connected to the bottom surface of the support plate 17. The vibration sensor 18 is used to monitor the vibration amplitude during the processing in real time and feed it back to the CNC system, which facilitates dynamic adjustment of process parameters and prevents quality defects caused by excessive vibration.

[0037] In this embodiment, different types of switch rails can be quickly switched by replacing the corresponding model of the contour module 12. The modular design significantly improves the versatility and reusability of the tooling.

[0038] The working process of a magnetic positioning fixture for machining the heel end of a forged point rail is as follows: 1. Preparation: Select the matching contour module 12 according to the model of the switch rail 20 to be processed and install it on the magnetic base 11. Ensure that the clamping position is consistent each time by using the positioning pin 14. 2. Place the workpiece: Place the forged point rail 20 smoothly on the support plate 17, and gradually bring its heel end closer to the contour module 12; 3. Positioning and fitting: As the switch rail 20 moves laterally, its waist arc surface 20a fits tightly with the contoured curved surface 12a. At the same time, the rail head inclined surface 20b and the rail bottom inclined surface 20c respectively contact the two contoured inclined surfaces 12b, forming a three-point close-fitting positioning system of "curved surface + double inclined surface", which automatically corrects the workpiece position and eliminates gaps. 4. Magnetic adsorption: When the magnetic switch 11a is operated to open the magnetic circuit, the strong magnetic field generated by the magnetic base 11 passes through the non-magnetic isolation layer and is conducted to the tip rail 20 through the large area metal contact surface, forming a closed magnetic circuit to achieve strong adsorption. 5. Status monitoring: The photoelectric switch 15 sends a processing permission signal after confirming that the workpiece is in place; the vibration sensor 18 continuously monitors the processing vibration to ensure process stability; 6. Complete the machining: After milling is completed, turn off the magnetic switch 11a, release the switch rail 20, and remove the finished product.

[0039] Through the aforementioned synergistic effect, this tooling achieves a transformation from "line contact" to "surface contact," increasing the contact area by no less than 400% compared to traditional planar tooling, and improving the adsorption force by more than 3 times. This effectively suppresses processing vibration and significantly improves processing accuracy and safety.

[0040] Therefore, the above-disclosed embodiments are merely illustrative in all respects and are not the only ones. All modifications within the scope of this utility model or its equivalents are included in this utility model.

Claims

1. A magnetic positioning fixture for machining the heel end of a forged point rail, characterized in that, include: Workbench (10); Two rows of magnetic bases (11) are symmetrically arranged on the upper side of the workbench (10), and a row of contouring modules (12) are connected to the inner side of each magnetic base (11) at intervals. The inner end face of the contouring module (12) is provided with a contouring curved surface (12a) that matches the rail waist arc surface (20a) at the heel end of the tip rail (20). The contoured curved surface (12a) has contoured inclined surfaces (12b) on its upper and lower sides respectively. The two contoured inclined surfaces (12b) are respectively matched with the rail head inclined surface (20b) and rail bottom inclined surface (20c) at the heel end of the switch rail (20). Each row of contouring modules (12) is provided with a support plate (17) below it, and the support plate (17) is horizontally installed on the upper side of the workbench (10).

2. The magnetic positioning fixture for machining the heel end of a forged point rail according to claim 1, characterized in that, The magnetic base (11) has a strong magnetic unit inside and is covered with a non-magnetic isolation layer on the outside, and a magnetic switch (11a) is rotatably connected to its outside.

3. The magnetic positioning fixture for machining the heel end of a forged point rail according to claim 1, characterized in that, The contouring module (12) is detachably connected to the inside of the magnetic base (11) by locking bolts (13) and positioning pins (14).

4. A magnetic positioning fixture for machining the heel end of a forged rail according to claim 1, characterized in that, The contouring module (12) is made of non-magnetic 7075 aluminum alloy with a thickness of 10mm.

5. A magnetic positioning fixture for machining the heel end of a forged point rail according to claim 1, characterized in that, The radius of curvature error of the contoured surface (12a) does not exceed ±0.5mm, and it has been optimized by finite element analysis to ensure uniform magnetic force distribution.

6. A magnetic positioning fixture for machining the heel end of a forged point rail according to claim 1, characterized in that, The inner side of the magnetic base (11) is connected to a photoelectric switch (15) via a sensor bracket (16).

7. A magnetic positioning fixture for machining the heel end of a forged point rail according to claim 1, characterized in that, A vibration sensor (18) is fixedly connected to the bottom surface of the support plate (17).

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