A method for processing a forging fork tip mounting hole

Abstract

The application provides a processing method for a forging fork tip mounting hole. The method formulates a complete process scheme, and starts from the modification processing of the bottom surface of a workpiece, the selection of a tooling, the clamping alignment, the selection of a main processing mode and a special tool, adopts a series of methods for control, and finally realizes the quick clamping alignment and efficient processing of the fork tip workpiece in a simple and efficient way, and is suitable for batch production of workpieces.

Description

Technical Field

[0001] This invention relates to the field of forging fork tip mounting hole processing technology, specifically a processing method for forging fork tip mounting holes. Background Technology

[0002] With the rapid development of high-speed passenger railways in my country, the application of high-speed turnouts is becoming increasingly widespread, offering advantages such as high locomotive speed and comfortable ride. The movable point rail of the CN high-speed turnout is forged from high-carbon alloy steel in the front half (forged fork tip), while the rear half uses a 60kg standard hardened rail as the heel connection rail, connected to the forged fork tip using flash welding. As the core component of the movable point rail of the CN high-speed turnout, the forged fork tip directly affects train speed and operational safety. The manufacturing technology requirements for its mounting holes for track switching, locking, and fixing are quite stringent, including: the dimensional accuracy of the hole itself, the positioning dimensional accuracy from the hole to the heel end face and bottom surface, the spacing accuracy within the hole group, and the perpendicularity accuracy of the center plane of the hole corresponding to the workpiece's length direction. Ensuring these manufacturing technical requirements requires the development of a practical and feasible method.

[0003] Currently, the machining of alloy head holes uses a relatively rudimentary clamping method: several support blocks, tightening screws, and stops are manually leveled and aligned, with wooden pads placed at the tip machining position for support. This method is only suitable for single-piece production without batch production. For mass-produced, standardized products, the lack of relatively fixed positioning and clamping has obvious disadvantages: 1. Alignment and clamping are time-consuming and labor-intensive; 2. The clamping accuracy is relatively poor, and it is difficult for the bottom surface of the workpiece to be aligned with the machine tool axis along its length, and the horizontal center is also difficult to be parallel with the machine tool worktable; 3. The machining position of the workpiece is prone to instability (especially when machining the front end hole by placing wood on the guard plate); 4. The positioning dimensions of the machined hole are prone to deviation. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a method for machining mounting holes for forged fork tips.

[0005] This invention employs the following technical solution: a fork tip drilling fixture overall clamping device, including a heel clamping device, an intermediate clamping device, a tip clamping device, a machine tool worktable, a forged fork tip, a replaceable drill bit body, and an alignment tool. When machining the forged fork tip, the heel clamping device and the tip clamping device are symmetrically arranged on the upper part of the machine tool worktable. The forged fork tip is clamped on opposite sides of the top of the heel clamping device and the tip clamping device. The intermediate clamping device is located at the first flange position of the forged fork tip and is positioned on the upper part of the machine tool worktable. The alignment tool includes a magnetic base, which is attracted to the lower end of the machine tool spindle. A scriber is installed at the measuring end of the magnetic base, and the scriber is located on one side of the forged fork tip. The forged fork tip is machined using a replaceable drill bit body. The specific steps for using the above-mentioned fork tip drilling fixture overall clamping device are as follows: S1. When milling the blank before heat treatment, a small amount of machining allowance is reserved at the bottom of the rail relative to the fishtail space. After the workpiece is heat treated, the bottom plane is used as the reference, and the rail straightening machine is used to level it. The workpiece deformation is roughly corrected first. Then, before drilling, the reserved allowance is removed by milling under the same Z value, so as to improve the bottom reference accuracy of the workpiece.

[0006] S2. Fixture alignment: After the heel clamping device, intermediate clamping device, and tip clamping device are fixed on the machine tool worktable, without installing all workpiece clamping parts, the fixture is aligned. First, the intermediate rigid fixture positioning block on the main body of the heel clamping device and the intermediate fixture positioning block on the main body of the tip clamping device are aligned by cutting along the X direction. Then, the two length-direction positioning surfaces on the main body of the tip clamping device are aligned by cutting along the Y direction. Finally, the vertical plate at the bottom of the main body of the heel clamping device is aligned by cutting along the Z direction.

[0007] S3. Specific procedure for workpiece clamping and alignment: Install the two forging fork tip clamps on the opposite sides of the heel clamping device and the tip clamping device, with the two fork tip flanges facing inwards. The rear end of the second flange should be flush against the vertical plate on the main body of the tip clamping device. Place them horizontally opposite each other. The intermediate clamping device is located at the position of the first flange of the forging fork tip. Then, rotate the lateral screws at each position to bring the workpiece closer to its respective intermediate rigid positioning block, but do not tighten them. At a certain section near the heel of each fork tip, use calipers to measure and draw the width center point O1. At a certain section near the tip of each fork tip, use the same method to draw the width center point O2. Use an alignment tool to attach its magnetic base to the spindle end. First, align the scriber with O1, then keep the Z-axis coordinate unchanged and move the spindle along the X-axis to position O2. Rotate the horizontal adjustment mechanism screw to move the workpiece up and down, and finally align O2 with the scriber (return to O1 for verification; if there are any problems, continue adjusting in this way). At this time, the center plane of the workpiece width is parallel to the machine tool table. After this alignment process is completed on both sides of the fork tip, first, laterally tighten the workpiece to the middle positioning block on the main body of each device, then rotate the wedge-shaped adjustable bracket screw at each position to make light contact with the underside of the workpiece flange at the corresponding position, and finally tighten all the pressure plates. At this time, the workpiece is clamped.

[0008] S4. Finally, to facilitate program adjustment and ensure the machining accuracy of positioning dimensions, the two workpieces each define their own workpiece coordinate system zero points, where the rail bottom plane is defined as the Y-axis zero point, the fork tip tail end as the X-axis zero point, and the workpiece width center line as the Z-axis zero point, for drilling machining.

[0009] As a further description of the above technical solution: the heel clamping device includes a tooling main body, with push rods at both ends and a top head at one end of each push rod. The top head consists of a top head and a cylindrical pin. A workpiece clamping component is located at the top of the middle part of the tooling main body, consisting of a T-slot extended bolt, a shouldered hexagonal nut, and a U-shaped pressure plate. A pad is located at the bottom of both ends of the workpiece clamping component. A tooling positioning component is located at the bottom of the tooling main body, consisting of a positioning key and a positioning key fixing screw. Tooling fasteners are installed on both sides of the tooling positioning component, consisting of hexagonal bolts, washers, and T-slot nuts. Through the tooling positioning component and the tooling fasteners, the tooling main body is positioned and fastened to the machine tool worktable.

[0010] As a further description of the above technical solution: the intermediate clamping device includes a base plate, and tooling clamping parts two are provided at both ends of the base plate. The tooling clamping parts two are composed of T-slot bolts, hexagonal nuts, and flat washers. The base plate is fixed on the machine tool worktable by the tooling clamping parts two. An adjustable bracket is provided on the upper part of the base plate. A rectangular pressure plate is installed on the upper part of the adjustable bracket. A workpiece clamping part two is provided in the middle of the rectangular pressure plate. The workpiece clamping part two is composed of T-slot extended bolts two and hexagonal nuts. The forging fork tip is fixed by clamping the rectangular pressure plate.

[0011] As a further description of the above technical solution: the adjustable support component one includes a base component one, the two ends of the base component one are provided with mounting and positioning holes, the base component one is installed on the top of the base plate component through the mounting and positioning holes, the top of the base component one is installed with an adjusting screw component one in the U-shaped groove, the top of the base component one is installed with a top cover fixing component one, the top cover fixing component one is composed of a top cover and an internal hexagon screw, the top cover is fixedly installed on the top of the base component one by the internal hexagon screw, and the other end of the adjusting screw component one is threadedly connected with a slider component one, the slider component one is slidably installed on the top of the base component one.

[0012] As a further description of the above technical solution: the tip clamping device includes a tooling main body component two. Two adjustable bracket components two are mounted on the top of one end of the tooling main body component two. Each adjustable bracket component two consists of an adjusting shim, an internal hexagonal screw, and an adjustable bracket, and the adjustable bracket has the same structure as the first adjustable bracket. A workpiece clamping component three is provided in the middle of the two adjustable bracket components two. The workpiece clamping component three consists of a hexagonal nut, a flat washer, a pressure plate, and a T-slot extended bolt. A top head component two is provided on both sides of the tooling main body component two. Each top head component two consists of a top rod, a top head, and a cylindrical pin. A workpiece clamping component four is provided at the other end of the top of the tooling main body component two. The workpiece clamping component four consists of a T-slot extended bolt. The fixture consists of four bolts, a shouldered hexagonal nut, and a U-shaped pressure plate. Two pads are provided on both sides of the top of the four workpiece clamping parts. Three clamping parts are provided through the top of the four sides of the fixture body part, each consisting of a T-slot bolt and a hexagonal nut. Lifting rings are fixedly installed on the top of both sides of the fixture body part. A fixture positioning part is provided at the bottom of the fixture body part, consisting of a positioning key and positioning screws. The fixture body part and the machine tool worktable are positioned and secured through the fixture positioning part and the fixture clamping parts. A length-direction positioning surface is provided on one side of the middle of the fixture body part. Horizontal adjustment parts are provided on the top of both sides of the fixture body part.

[0013] As a further description of the above technical solution: the horizontal adjustment component includes a base component two, and a top cover fixing component two is bolted to the top of the base component two. An adjusting screw component two is rotatably installed on the opposite side of the top cover fixing component two and the base component two. A slider component two is threaded to the outer side of the other end of the adjusting screw component two. A compression spring adjusting component is provided on the top of the slider component two. The compression spring adjusting component is composed of a support block, a spring, and a compression spring bolt.

[0014] As a further description of the above technical solution: one end of the forged fork tip has a heel end plane, one end of the forged fork tip has a tail mounting hole, both sides of one end of the forged fork tip have fishtail spaces, one side of one end of the forged fork tip has a first flange, the inside of the first flange has a plurality of flange mounting holes, one side of the other end of the forged fork tip has a second flange, the inside of the second flange has a plurality of flange mounting holes, one side of the middle of the forged fork tip has a pull-down device groove, one side of the forged fork tip is a top surface, the other side of the forged fork tip is a bottom surface, the bottom surface has three base plate mounting grooves, the other end of the forged fork tip has a tip plane, and the bottom of the forged fork tip has a allowance reserve area.

[0015] As a further description of the above technical solution: the number of forging fork tips is two, that is, two workpieces are clamped at one time, and all upper and lower clamping devices are shared.

[0016] As a further description of the above technical solution: the replaceable drill bit body is a replaceable drill bit, both the handle and the cutting tool are equipped with a center water outlet function, and it has Φ30.5 drill bit and Φ25 drill bit specifications. The top of the replaceable drill bit body is equipped with a replaceable alloy drill bit, and the top of the replaceable alloy drill bit has a drill bit angle.

[0017] As a further description of the above technical solution: In step S4, for each workpiece, the zero-point coordinates are defined in the program using different user variable R values.

[0018] This invention provides an improved method for machining mounting holes for forged fork tips, which, compared with the prior art, has the following improvements and advantages: Firstly, this processing method is equipped with special tooling and custom-made cutting tools. Based on the characteristics of the workpiece, a special tooling for machining alloy head holes has been designed to achieve rapid clamping and alignment of irregularly shaped workpieces and efficient processing, which is suitable for mass production of workpieces. Secondly, based on the characteristics of the workpiece, a novel manual clamping mechanism was designed, such as wedge-shaped adjustable support, bottom surface fixing and corresponding tightening mechanism, which makes the workpiece clamping stable and highly accurate.

[0019] Thirdly, the methods for leveling the workpiece include the leveling adjustment method, the use of the wedge leveling adjustment mechanism, and the application of a special leveling tool with a magnetic base and a scribing needle, which makes it easy to adjust the horizontal center of the workpiece and prevents it from changing after adjustment.

[0020] Fourthly, the drilling method of cutting to the bottom, drilling through and stopping, and working feed and retraction improves the surface quality of the hole. Two workpieces can be clamped at one time, and the clamping device is shared, saving the clamping time of a single piece. In summary, this method has developed a complete process plan, and has adopted a series of methods to control the workpiece bottom surface correction, tooling selection, clamping and alignment, main machining methods and special tool selection. Finally, it achieves rapid clamping and alignment and efficient machining of fork tip workpieces in a simple and efficient manner, which is suitable for mass production of workpieces. Attached Figure Description

[0021] The present invention will be further explained below with reference to the accompanying drawings and embodiments: Figure 1 This is a schematic diagram of the forged fork tip structure provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the fork tip bottom plane correction machining provided in an embodiment of the present invention; Figure 3 This is a schematic diagram showing the allowance reserved at the bottom of the fork tip rail provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the overall mounting of the fork tip drilling tool provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the heel-end mounting device provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of an intermediate loading device provided in an embodiment of the present invention; Figure 7 This is a schematic diagram of an adjustable bracket provided in an embodiment of the present invention; Figure 8 This is a schematic diagram of the tip mounting device structure provided in an embodiment of the present invention; Figure 9 This is a schematic diagram of the horizontal adjustment mechanism provided in an embodiment of the present invention; Figure 10 This is a schematic diagram of tooling alignment from top view and AA side section perspective provided in an embodiment of the present invention; Figure 11 This is a schematic diagram of the replaceable drill bit and drill tip structure provided in an embodiment of the present invention; Figure 12 This is a schematic diagram of the center point plotting the width of the fork tip provided in an embodiment of the present invention; Figure 13 This is a schematic diagram of horizontal center point alignment provided in an embodiment of the present invention; Figure 14 This is a schematic diagram of the zero point of the workpiece coordinates provided in an embodiment of the present invention.

[0022] In the diagram: 1. Heel clamping device; 101. Top rod; 102. Main tooling component one; 103. Top head component one; 104. Tooling positioning component one; 105. Tooling fastener one; 106. Workpiece clamping component one; 107. Pad one; 2. Intermediate clamping device; 201. Tooling clamping component two; 202. Base plate; 203. Adjustable bracket component one; 2031. Base component one; 2032. Adjusting screw component one; 2033. Top cover fixing component one; 2034. 1. Slider 1; 204. Rectangular pressure plate; 205. Workpiece clamping component 2; 3. Tip mounting device; 301. Adjustable bracket component 2; 302. Workpiece clamping component 3; 303. Top head component 2; 304. Tooling main body component 2; 305. Workpiece clamping component 4; 306. Pad block 2; 307. Horizontal adjustment component; 3071. Base component 2; 3072. Adjusting screw component 2; 3073. Top cover fixing component 2; 3074. Slider 2; 3075. Compression spring adjustment component; 308. Tooling clamping component three; 309. Lifting ring; 310. Tooling positioning component two; 311. Length direction positioning elevation; 4. Machine tool worktable; 5. Forged fork tip; 501. Heel end plane; 502. Tail mounting hole; 503. Fish tail space; 504. First flange; 505. First flange mounting hole; 506. Bottom surface; 507. Top surface; 508. Pull-down device groove; 509. Base plate mounting groove; 510. Second flange; 511. Second flange mounting hole; 512. Tip plane; 513. Allowance reserved area; 6. Replaceable drill tip type drill bit body; 601. Replaceable alloy drill tip; 602. Drill tip angle; 7. Alignment tool; 701. Magnetic base; 702. Scribing needle. Detailed Implementation

[0023] To make the technical means, creative features, objectives, and effects of this invention readily understandable, the invention is further described below with reference to specific illustrations. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0024] Please see Figure 1 - Figure 14This invention provides a technical solution: a method for machining mounting holes for forged fork tips, which uses a fork tip drilling fixture overall clamping device, including a heel clamping device 1, an intermediate clamping device 2, a tip clamping device 3, a machine tool worktable 4, a forged fork tip 5, a replaceable drill bit body 6, and an alignment tool 7. When machining the forged fork tip 5, the heel clamping device 1 and the tip clamping device 3 are symmetrically arranged on the upper part of the machine tool worktable 4, and the forged fork tip 5 is clamped and mounted on the heel clamping device 1 and the tip clamping device 3. On the opposite side of the top of device 3, the intermediate clamping device 2 is located at the first flange 504 of the forging fork tip 5, and the intermediate clamping device 2 is set on the upper part of the machine tool worktable 4. The alignment tool 7 includes a magnetic base 701, which is attracted to the lower end of the machine tool spindle. The measuring end of the magnetic base 701 is equipped with a scribing needle 702, and the scribing needle 702 is located on one side of the forging fork tip 5. The forging fork tip 5 is machined using a replaceable drill bit body 6. The specific steps for using the above-mentioned fork tip drilling tooling overall clamping device are as follows: S1. When milling the blank before heat treatment, a small amount of machining allowance reserve area 513 is reserved at the bottom of the rail relative to the fishtail space 503. After the workpiece is heat treated, the bottom plane is used as the reference, and the rail straightening machine is used to level it. The workpiece deformation is roughly corrected first. Then, before drilling, the previously reserved allowance reserve area 513 is removed by milling under the same Z value, so as to improve the bottom reference accuracy of the workpiece.

[0025] S2. Tooling Alignment: After the heel clamping device 1, intermediate clamping device 2, and tip clamping device 3 are fixed on the machine tool worktable 4, without installing all workpiece clamping parts, the tooling is aligned. First, the intermediate rigid tooling positioning block on the main body of the heel clamping device 1 and the intermediate tooling positioning block on the main body of the tip clamping device 3 are cut and aligned along the X direction. Then, the two length-direction positioning surfaces 311 on the main body of the tip clamping device 3 are cut and aligned along the Y direction. Finally, the vertical plate at the bottom of the main body of the heel clamping device 1 is cut and aligned along the Z direction. S3. Specific procedure for workpiece clamping and alignment: Clamp the two forged fork tips 5 onto the opposite sides of the heel clamping device 1 and the tip clamping device 3, with the two fork tip flanges facing inwards. The rear end face of the second flange 510 should be tightly against the vertical plate on the main body of the tip clamping device 3, placed horizontally opposite each other. The intermediate clamping device 2 is located at the position of the first flange 504 of the forged fork tip 5. Then, rotate the lateral screws at each position to bring the workpiece closer to its respective intermediate rigid positioning block, but do not tighten them. Near a section near the heel of each fork tip, use calipers to measure and draw the width center point O1. Near a section near the tip of the fork tip, use the same method to draw the width center point O2. Use the alignment tool 7 to attach its magnetic base 701 to... Face the spindle end face and place the scriber 702 horizontally. First, align the scriber 702 with O1. Then, keeping the Z-axis coordinate unchanged, move the spindle along the X-axis to position O2. Rotate the horizontal adjustment mechanism screw to move the workpiece up and down, and finally align O2 with the scriber 702 (return to O1 for verification; if there are any problems, continue adjusting in this way). At this time, the center plane of the workpiece width is parallel to the machine tool table 4. After this alignment process is completed on both sides of the fork tip, first, laterally tighten the workpiece to the middle positioning block on its respective device body. Then, rotate the wedge-shaped adjustable support screw at each position to make light contact with the underside of the workpiece flange at the corresponding position. Finally, tighten all the pressure plates. At this time, the workpiece is clamped.

[0026] S4. Finally, to facilitate program adjustment and ensure the machining accuracy of positioning dimensions, the two workpieces each define their own workpiece coordinate system zero points, where the rail bottom plane is defined as the Y-axis zero point, the fork tip tail end as the X-axis zero point, and the workpiece width center line as the Z-axis zero point, for drilling machining.

[0027] In another implementation scheme, such as Figure 4 and Figure 5 As shown, the end-mounting device 1 includes a tooling main body 102. Both ends of the tooling main body 102 are provided with push rods 101. One end of each push rod 101 is provided with a top head 103, which consists of a top head and a cylindrical pin. The top of the middle part of the tooling main body 102 is provided with a workpiece clamping component 106, which consists of a T-slot extended bolt, a shouldered hexagonal nut, and a U-shaped pressure plate. The bottom of both ends of the workpiece clamping component 106... Each fixture is equipped with a pad 107. The bottom of the fixture body 102 is equipped with a fixture positioning component 104, which consists of a positioning key and a positioning key fixing screw. Fixture fasteners 105 are installed on both sides of the fixture positioning component 104, which consists of a hexagonal bolt, a washer, and a T-slot nut. The fixture body 102 is positioned and fastened to the machine tool worktable 4 through the fixture positioning component 104 and the fixture fasteners 105.

[0028] The end clamping device 1 is a set of top clamping and pressing mechanism. By rotating the fastening screws on both sides, the bottom surface 506 of the workpiece can be pressed against the rigid positioning block with a large volume in the middle of the main body to achieve left and right clamping. The lower plate of the main body plays a supporting role. After the nut on the top U-shaped pressure plate is tightened, the workpiece can be clamped up and down.

[0029] In another implementation scheme, such as Figure 4 and Figure 6 As shown, the intermediate clamping device 2 includes a base plate 202. Tooling clamping parts 201 are provided at both ends of the base plate 202. Tooling clamping parts 201 are composed of T-slot bolts, hexagonal nuts, and flat washers. The base plate 202 is fixed to the machine tool worktable 4 by the tooling clamping parts 201. An adjustable bracket 203 is provided on the upper part of the base plate 202. A rectangular pressure plate 204 is installed on the upper part of the adjustable bracket 203. A workpiece clamping part 205 is provided in the middle of the rectangular pressure plate 204. The workpiece clamping part 205 is composed of T-slot extended bolts and hexagonal nuts. The forging fork tip 5 is fixed by clamping the rectangular pressure plate 204.

[0030] The intermediate clamping device 2 has two adjustable brackets 203 installed on the base plate. When the forging fork tip 5 is clamped, the adjustable brackets 203 are adjusted so that the upper surface of the slider 2034 contacts the first flange 504 for support. Then, the rectangular pressure plate 204 cooperates with the workpiece clamping part 205 to clamp it.

[0031] In another implementation scheme, such as Figures 4-7 As shown, the adjustable bracket 203 includes a base 2031. The base 2031 has mounting holes at both ends and is mounted on the top of the base plate 202 via these holes. An adjusting screw 2032 is installed in the U-shaped groove at the top of the base 2031. A top cover fixing 2033 is installed on the top of the base 2031. The top cover fixing 2033 consists of a top cover and hexagonal socket screws. The top cover is fixed to the top of the base 2031 by the hexagonal socket screws. A slider 2034 is threaded onto the outer side of the other end of the adjusting screw 2032 and slides on the top of the base 2031.

[0032] Adjustable bracket 203, structural diagram as follows Figure 7 As shown, the size is relatively small. Its slider 2034 and base 2031 adopt a sloping contact structure. After rotating the adjusting screw 2032, the slider 2034 can move up and down.

[0033] In another implementation scheme, such as Figures 1-8As shown, the tip clamping device 3 includes a tooling main body 304. Two adjustable brackets 301 are mounted on the top of one end of the tooling main body 304. Each adjustable bracket 301 consists of an adjusting shim, an internal hexagonal screw, and an adjustable bracket component. The adjustable bracket component has the same structure as the adjustable bracket 203. A workpiece clamping component 302 is located in the middle of the adjustable bracket 301. The workpiece clamping component 302 consists of a hexagonal nut, a flat washer, a pressure plate, and a T-slot extension bolt. Top heads 304 are located on both sides of the tooling main body 304. 303, the top part 2 303 consists of a top rod, a top head, and a cylindrical pin. The other end of the top of the main tooling part 2 304 is equipped with a workpiece clamping part 4 305, which consists of a T-slot extended bolt, a shouldered hexagonal nut, and a U-shaped pressure plate. Both sides of the top of the workpiece clamping part 4 305 are equipped with pads 2 306. The top four sides of the main tooling part 2 304 are all perforated with tooling clamping parts 308, which consist of T-slot bolts and hexagonal nuts. The tops of both sides of the main tooling part 2 304 are equipped with pads 2 306. A lifting ring 309 is fixedly installed. A tooling positioning component 310 is located at the bottom of the main tooling component 304. The tooling positioning component 310 consists of a positioning key and positioning screws. The main tooling component 304 and the machine tool worktable 4 are positioned and secured by the tooling positioning component 310 and the tooling clamping component 308. A length-direction positioning surface 311 is provided on one side of the middle of the main tooling component 304. Horizontal adjustment components 307 are provided on the top of both sides of the main tooling component 304. The horizontal adjustment component 307 includes a base component 307. 1. The base component 2 3071 is installed on the top of the tooling main body component 2 304 by an internal hexagonal screw. The top of the base component 2 3071 is bolted to the top of the cover fixing component 2 3073. The adjusting screw component 2 3072 is rotatably installed on the opposite side of the cover fixing component 2 3073 and the base component 2 3071. The other end of the adjusting screw component 2 3072 is threaded to the outer side of the slider component 2 3074. The top of the slider component 2 3074 is provided with a compression spring adjusting component 3075, which consists of a support block, a spring, and a compression spring bolt.

[0034] The main functions of the tip clamping device 3 are: clamping and fixing the second flange 510, lateral clamping of the workpiece, positioning of the workpiece in the length direction, and horizontal adjustment of the workpiece.

[0035] ① The fixing and clamping of the second flange 510 is similar to the structure of the intermediate clamping device 2. Two adjustable brackets 301 are installed at the front end of the main body. By adjusting the adjustable brackets, the upper surface of the slider is brought into contact with the second flange 510 for support. Then, the pressure plate of the workpiece clamping component 302 and the T-slot bolt of the workpiece clamping component 302 are used for clamping. ② Lateral clamping of the workpiece: By rotating the fastening screws on both sides, the bottom surface 506 of the workpiece can be pressed against the large rigid positioning block in the middle of the main body to achieve left and right clamping.

[0036] ③ Workpiece length direction positioning: Since the equipment used for drilling the fork tip 5 in this forging process is smaller than the workpiece, the workpiece is not positioned by the tip or tail end in the length direction. Instead, the vertical plate on the main body is used to position the workpiece by the rear end face of the second flange 510.

[0037] ④ At the rear end of the device, two horizontal adjustment components 307 are installed, the detailed structure of which is as follows: Figure 9 As shown, slider 3074 and support block are in inclined contact. After rotating adjusting screw 3072, slider 3074 moves horizontally. Support block moves up and down under the limiting action of the base groove surrounding it, thereby driving the supported workpiece to rise and fall. The spring dampens the support block under the action of the compression bolt, making the mechanism run smoothly and preventing it from disengaging from the base groove. When the workpiece is initially clamped, the horizontal adjusting component 307 adjusts the height position of the workpiece tip, and then uses the U-shaped pressure plate and T-slot bolt to clamp it.

[0038] In another implementation scheme, such as Figures 1-8 As shown, one end of the forged fork tip 5 has a heel end plane 501, one end of the forged fork tip 5 has a tail mounting hole 502, and both sides of one end of the forged fork tip 5 have fishtail spaces 503. One side of one end of the forged fork tip 5 has a first flange 504, and the interior of the first flange 504 has several flange mounting holes 505. One side of the other end of the forged fork tip 5 has a second flange 510, and the interior of the second flange 510 has several flange mounting holes 511. One side of the middle of the forged fork tip 5 has a pull-down device groove 508. One side of the forged fork tip 5 is a top surface 507, and the other side of the forged fork tip 5 is a bottom surface 506. The bottom surface 506 has three base plate mounting grooves 509. The other end of the forged fork tip 5 has a tip plane 512, and the bottom of the forged fork tip 5 has a reserve area 513.

[0039] Overall, the forged fork tip 5 is a long rod with a shape that is narrower at the front and wider at the back, and is symmetrical along the width center; two mounting flanges are arranged at the front and rear, and a pull-down groove is arranged in the middle position; the boss and pull-down groove are both on one side of the bottom plane and extend outward from the bottom plane; three base plate mounting slots 509 are arranged on the bottom plane; fishtail spaces 503 are arranged in the middle position on both sides of the heel end to keep the external shape consistent when connected with the standard rail.

[0040] The fork tip mounting hole is divided into three parts: the first part is located in the tail space 503, the second part is located in the first flange 504, and the third part is located in the second flange 510.

[0041] To meet the manufacturing technical requirements of the forged fork tip mounting hole, its machining must be controlled through a series of methods, starting with the correction machining of the workpiece bottom surface 506, tooling selection, clamping and alignment, main machining methods, and selection of special tools. Specifically, this includes: 1. Correction machining of the 506 stainless steel fork tip bottom surface: After milling the blank, a heat treatment is required to improve its strength. The rail base serves as the reference plane; if heat treatment deformation occurs, it can cause slight distortion of the mounting holes relative to the workpiece as a whole and its corresponding sections. This can lead to poor fit between the fork tip and the base plate / wing rail when the locking device rotates the traction rail, resulting in jamming. To ensure the accuracy of the rail base plane, the following targeted countermeasures are formulated: 1. When milling the blank before heat treatment, a small machining allowance reserve area 513 is reserved at the bottom of the rail relative to the fishtail space 503, with an allowance of about 2mm.

[0042] 2. After heat treatment, the workpiece is leveled using a rail straightening machine with the bottom plane as the reference, and the workpiece deformation is roughly corrected first.

[0043] 3. Before drilling, the previously reserved rail bottom allowance is removed by milling under the same Z value, thereby improving the bottom reference accuracy of the workpiece.

[0044] In another implementation scheme, such as Figures 1-12 As shown, there are two forging fork tips 5, which means that two workpieces are clamped at a time, and all upper and lower clamping devices are shared.

[0045] The overall assembly of the fork-tip drilling fixture is shown in the diagram. Figure 4 As shown, the key points of its process are as follows: ① Two workpieces can be clamped at once, and all upper and lower clamping devices are shared, saving about half of the clamping time.

[0046] ② The clamping mechanism is relatively simple and strong. All wrench opening values ​​used for clamping and tightening points are the same, which can save time during clamping.

[0047] ③ A horizontal support point is set at the tail end of the workpiece, and a wedge-shaped horizontal adjustment point is set at the tip, so that the horizontal center of the workpiece can be easily adjusted and is not easily changed after adjustment.

[0048] ④ Rigid positioning blocks and corresponding clamping mechanisms are provided at both the tail end and tip of the workpiece, which are in close contact with the bottom surface 506, so that the bottom surface 506 of the workpiece is aligned with the machine tool axis along the length direction.

[0049] ⑤ The two bosses containing the machining hole are each equipped with wedge-shaped adjustable supports and local clamping at both ends to ensure stable mounting at the local machining position.

[0050] ⑥ Keep the machined holes basically within the center stroke of the machine tool, reduce the local protrusion of the hole position, and make the clamping more stable.

[0051] ⑦ Each tooling body is equipped with positioning keys and special fixing accessories, making installation easy during model changeover and ensuring high positioning accuracy with repeated use.

[0052] In another implementation scheme, such as Figures 1-11 As shown, the replaceable drill bit body 6 is a replaceable drill bit, with both the shank and the cutting tool equipped with a center water outlet function, and it has Φ30.5 drill bit and Φ25 drill bit specifications. The top of the replaceable drill bit body 6 is equipped with a replaceable alloy drill bit 601, and the top of the replaceable alloy drill bit 601 is provided with a drill bit angle 602.

[0053] The basic information about the fork tip mounting holes is shown in the table below:

[0054] ① Considering the workpiece is made of high-carbon alloy steel R350HT with a high hardness of 350-390HB, the main tool type procured this time is replaceable drill bits with alloy drill tips. Both the tool holder and the tool are equipped with center cooling. The tool structure is shown in the diagram below. Figure 11 As shown in Figure ②, although the upper and lower surfaces of the workpiece form inclined planes for the tool machining when the workpiece is clamped, the infeed and exit angles of 1.1° and 0.92° are not large and have little impact on the direct machining of the tool. Therefore, the tool type purchased this time did not include a center drill. The drill bit specifications were selected according to the hole diameter tolerance and hole depth: for Φ30 holes, a Φ30.5 drill bit with a diameter of 5 times was selected; for Φ25 holes, a Φ25 drill bit with a diameter of 3 times was selected.

[0055] In another implementation scheme, such as Figure 10 , Figures 12-14 As shown, in step S4, for each workpiece, the zero-point coordinates are defined in the program using different user variable R values.

[0056] To facilitate program adjustment and ensure the accuracy of positioning dimensions, each workpiece has its own workpiece coordinate system zero point, with the rail bottom plane defined as the Y-axis zero point, the fork tip tail end as the X-axis zero point, and the workpiece width centerline as the Z-axis zero point.

[0057] For each workpiece, the zero-point coordinates are defined in the program using different user-defined variable R values: for example, R11 and R12 correspond to zero points X1 and Y1 respectively, and R21 and R22 correspond to zero points X2 and Y2 respectively. The actual coordinate values ​​are obtained by subtracting the tool radius from the tool side edge at the corresponding position on the workpiece. R31 corresponds to the common zero Z of the two workpieces, which is obtained by lightly touching the workpiece surface with the tool tip and subtracting half of the thickness value at the corresponding position.

[0058] Calculate the position dimensions of each hole relative to the X and Y zero points, define the position coordinates of the holes, and define the starting and ending coordinates (Z-axis values) of the drilling based on the workpiece thickness value B at each hole. For example, the starting coordinate of a certain hole is B1 / 2+10 and the ending coordinate is -B1 / 2-5.

[0059] Working principle: Main processing steps

[0060] 1) Workpiece clamping and alignment: With the two forked protrusions facing inwards, and the rear end face of the second protrusion 510 pressed against the upright plate on the main body of the tip mounting device 3, place them horizontally opposite each other. Then rotate the lateral screws at each position to bring the workpieces closer to their respective central rigid positioning blocks, but do not tighten them.

[0061] At a cross-section near the heel of each fork tip, use calipers to measure and mark the width center point O1. At a cross-section near the tip of the fork tip, use the same method to mark the width center point O2. Using the alignment tool 7, attach the magnetic base 701 to the spindle end face and place the scriber 702 horizontally. First, align the scriber 702 with O1. Then, keeping the Z-axis coordinate unchanged, move the spindle along the X-axis to position O2. Rotate the horizontal adjustment mechanism screw to move the workpiece up and down, and finally align O2 with the scriber 702 (return to O1 for verification; if there are any problems, continue adjusting in this way). At this time, the width center plane of the workpiece is parallel to the machine tool table 4. After this alignment process is completed on both fork tips, first, laterally tighten the workpiece to the intermediate positioning block on its respective device body. Then, rotate the wedge-shaped adjustable support screw at each position to make light contact with the underside of the workpiece flange at the corresponding position. Finally, tighten all the pressure plates. At this time, the workpiece is clamped. The diagram of fork tip width center marking and horizontal center alignment is as follows. Figure 12 , Figure 13 As shown.

[0062] 2) Drilling

[0063] ① To facilitate program adjustment and ensure the machining accuracy of positioning dimensions, the two workpieces each define their own workpiece coordinate system zero points, wherein the rail bottom plane is defined as the Y-axis zero point, the fork tip tail end is defined as the X-axis zero point, and the workpiece width center line is defined as the Z-axis zero point.

[0064] ② For each workpiece, the zero-point coordinates are defined in the program using different user-defined variable R values: for example, R11 and R12 correspond to zero points X1 and Y1 respectively, and R21 and R22 correspond to zero points X2 and Y2 respectively. The actual coordinate values ​​are obtained by subtracting the tool radius from the tool side edge at the corresponding position on the workpiece. R31 corresponds to the common zero Z of the two workpieces, which is obtained by lightly touching the workpiece surface with the tool tip and subtracting half of the thickness value at the corresponding position.

[0065] ③ Calculate the position dimensions of each hole relative to the X and Y zero points, define the position coordinates of the holes, and define the starting and ending coordinates (Z-axis values) of the drilling based on the workpiece thickness value B at each hole. For example, the starting coordinate of a certain hole is B1 / 2+10 and the ending coordinate is -B1 / 2-5.

[0066] ④ Because it is difficult to measure the distance between the first flange 504, the second flange 510 and their mounting holes and the bottom surface 506, the tail end Φ30 hole is machined first. The distance between the tail end and the bottom surface 506 can be measured more easily with calipers. Before machining, the workpiece surface should be lightly scratched with the tip of the tool according to the hole coordinates and the positioning dimension should be measured. The zero point of the workpiece coordinates is corrected accordingly.

[0067] ⑤ Based on the corrected workpiece coordinate zero point, perform machining of the mounting holes for the first flange 504 and the second flange 510Φ25.

[0068] ⑥ Drilling Feed Method: Due to the high hardness of the workpiece and the slight backlash in the transmission and feed of the drilling machine after a period of daily operation, a ring-shaped ridge always appears at the connection point of each chip removal operation when using the conventional tool-lifting and chip-removing drilling cycle command. Furthermore, the surface roughness of the hole wall is unacceptable. Using a pilot hole + boring or reaming method would both affect production efficiency and increase costs. Through machining experiments, we adjusted the drilling method as follows: a. When feeding the tool, cut to the bottom and cancel the chip removal by lifting the tool. Since the tool tip is made of high-quality cemented carbide and the machine tool has a powerful internal cooling system, the chip removal and machining cooling effects are also very good.

[0069] b. After the tool penetrates the workpiece, use the G04 command to pause the feed for a short time to restore the tool wobbling caused by the rapid change in cutting force during penetration.

[0070] c. When retracting the drill bit, change the conventional G0 rapid feed to G1…F2000 high-speed working feed. The retraction time of the two is not much different, but it can eliminate the scratches on the hole sidewall caused by the drill bit during retraction.

[0071] d. This drilling method results in stable and smooth cutting, a smooth and flat hole interior, and no abnormal tool damage.

[0072] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for machining a forged fork tip mounting hole, which uses a fork tip drilling fixture overall clamping device, including a heel clamping device (1), an intermediate clamping device (2), a tip clamping device (3), a machine tool worktable (4), a forged fork tip (5), a replaceable drill bit body (6), and an alignment tool (7). When machining the forged fork tip (5), the heel clamping device (1) and the tip clamping device (3) are symmetrically arranged on the upper part of the machine tool worktable (4), and the forged fork tip (5) is clamped in the heel clamping device (1) and the tip clamping device (3). On the opposite side of the top of the clamping device (3), the intermediate clamping device (2) is located at the position of the first flange (504) of the forging fork tip (5), and the intermediate clamping device (2) is set on the upper part of the machine tool worktable (4). The alignment tool (7) includes a magnetic base (701) which is attracted to the lower end of the machine tool spindle. The measuring end of the magnetic base (701) is equipped with a scribing needle (702), and the scribing needle (702) is located on one side of the forging fork tip (5). The forging fork tip (5) is processed by a replaceable drill bit body (6). The feature is that: The specific steps for using the above-mentioned fork-tip drilling tooling overall clamping device are as follows: S1. When milling the blank before heat treatment, a small amount of machining allowance is reserved in the bottom of the rail (513) relative to the fishtail space (503). After the workpiece is heat treated, the bottom plane is used as the reference, and the rail straightening machine is used to level it. The workpiece deformation is roughly corrected first. Then, before drilling, the reserved allowance area (513) is removed by milling under the same Z value, so as to improve the bottom reference accuracy of the workpiece. S2. Tooling alignment: After the heel end clamping device (1), intermediate clamping device (2), and tip clamping device (3) are fixed on the machine tool worktable (4), without installing all workpiece clamping parts, the tooling is aligned. First, the intermediate rigid tooling positioning block on the main body of the heel end clamping device (1) and the intermediate tooling positioning block on the main body of the tip clamping device (3) are cut and aligned along the X direction. Then, the two length direction positioning surfaces (311) on the main body of the tip clamping device (3) are cut and aligned along the Y direction. Finally, the vertical plate at the bottom of the main body of the heel end clamping device (1) is cut and aligned along the Z direction. S3. Specific process for workpiece clamping and alignment: The two forging fork tips (5) are clamped and mounted on the opposite sides of the heel clamping device (1) and the tip clamping device (3), with the flanges of the two fork tips facing inwards and the rear end face of the second flange (510) tightly attached to the vertical plate on the main body of the tip clamping device (3). They are placed horizontally opposite to each other, and the middle clamping device (2) is located at the position of the first flange (504) of the forging fork tip (5). Then, rotate the lateral screws at each position to bring the workpiece closer to its respective middle rigid positioning block, but do not tighten it. At a certain section near the heel of each fork tip, use calipers to measure and draw the width center point O1. At a certain section near the tip of the fork tip, use the same method to draw the width center point O2. Use the alignment tool ( 7) Attach the magnetic base (701) to the end face of the spindle and place the scriber (702) horizontally. First, align the scriber (702) with O1. Then, keep the Z-axis coordinate unchanged and move the spindle along the X-axis to position O2. Rotate the horizontal adjustment mechanism screw to move the workpiece up and down and finally align O2 with the scriber (702). At this time, the center plane of the workpiece width is parallel to the machine tool table (4). After this alignment process is completed on both sides of the fork tip, first, tighten the workpiece to the middle positioning block on the main body of each device from the side. Then, rotate the wedge adjustable bracket screw at each position and make light contact with the workpiece flange at the corresponding position. Finally, tighten all the pressure plates. At this time, the workpiece is clamped. S4. Finally, to facilitate program adjustment and ensure the machining accuracy of positioning dimensions, the two workpieces each define their own workpiece coordinate system zero points, where the rail bottom plane is defined as the Y-axis zero point, the fork tip tail end as the X-axis zero point, and the workpiece width center line as the Z-axis zero point, for drilling machining.

2. The method for machining a forged fork tip mounting hole according to claim 1, characterized in that: The heel clamping device (1) includes a tooling main body (102), with top rods (101) at both ends of the tooling main body (102), and a top head (103) at one end of the top rods (101). The top head (103) consists of a top head and a cylindrical pin. A workpiece clamping part (106) is provided at the top of the middle part of the tooling main body (102). The workpiece clamping part (106) consists of a T-slot extended bolt, a shouldered hexagonal nut, and a U-shaped pressure plate. The bottom of both ends of the workpiece clamping part (106) is also provided. Each is equipped with a pad block (107). The bottom of the tooling main body component (102) is equipped with a tooling positioning component (104). The tooling positioning component (104) consists of a positioning key and a positioning key fixing screw. Tooling fasteners (105) are installed on both sides of the tooling positioning component (104). The tooling fasteners (105) consist of hexagonal bolts, washers, and T-slot nuts. Through the tooling positioning component (104) and the tooling fasteners (105), the tooling main body component (102) and the machine tool worktable (4) are positioned and fastened.

3. The method for machining a forged fork tip mounting hole according to claim 1, characterized in that: The intermediate clamping device (2) includes a base plate (202), and tooling clamping parts two (201) are provided at both ends of the base plate (202). The tooling clamping parts two (201) are composed of T-slot bolts, hexagonal nuts and flat washers. The base plate (202) is fixed on the machine tool worktable (4) by the tooling clamping parts two (201). An adjustable bracket part one (203) is provided on the upper part of the base plate (202). A rectangular pressure plate (204) is installed on the upper part of the adjustable bracket part one (203). A workpiece clamping part two (205) is provided in the middle of the rectangular pressure plate (204). The workpiece clamping part two (205) is composed of T-slot extended bolts two and hexagonal nuts. The forging fork tip (5) is fixed by clamping the rectangular pressure plate (204).

4. The method for machining a forged fork tip mounting hole according to claim 3, characterized in that: The adjustable bracket component 1 (203) includes a base component 1 (2031). The base component 1 (2031) has mounting and positioning holes at both ends. The base component 1 (2031) is mounted on the top of the base plate component (202) through the mounting and positioning holes. An adjusting screw component 1 (2032) is installed in the U-shaped groove at the top of the base component 1 (2031). A top cover fixing component 1 (2033) is installed on the top of the base component 1 (2031). The top cover fixing component 1 (2033) consists of a top cover and an internal hexagon screw. The top cover is fixedly installed on the top of the base component 1 (2031) by the internal hexagon screw. A slider 1 (2034) is threaded to the outer side of the other end of the adjusting screw component 1 (2032). The slider 1 (2034) is slidably installed on the top of the base component 1 (2031).

5. The method for machining a forged fork tip mounting hole according to claim 4, characterized in that: The tip clamping device (3) includes a tooling main body (304). Two adjustable brackets (301) are installed on the top of one end of the tooling main body (304). The adjustable brackets (301) consist of adjusting shims, hexagonal screws, and adjustable brackets. The adjustable brackets have the same structure as the adjustable brackets (203). A workpiece clamping part (302) is provided in the middle of the two adjustable brackets (301). Fastener 3 (302) consists of a hexagonal nut, a flat washer, a pressure plate, and three T-slot extended bolts. Both sides of the main body of the tooling 2 (304) are provided with top head 2 (303), which consists of a top rod, a top head, and a cylindrical pin. The other end of the top of the main body of the tooling 2 (304) is provided with workpiece clamping part 4 (305), which consists of four T-slot extended bolts, a shouldered hexagonal nut, and a U-shaped pressure plate assembly. The workpiece clamping component four (305) is provided with pads two (306) on both sides of the top. The tooling main body component two (304) is provided with tooling clamping components three (308) through all four sides of the top. The tooling clamping components three (308) are composed of T-slot bolts and hexagonal nuts. The top of both sides of the tooling main body component two (304) is fixedly installed with lifting rings (309). The bottom of the tooling main body component two (304) is provided with tooling positioning components two (309). 10), the tooling positioning component two (310) is composed of positioning key and positioning mounting screw. The tooling main body component two (304) and the machine tool worktable (4) are positioned and fastened by the tooling positioning component two (310) and the tooling clamping component three (308). A length direction positioning surface (311) is opened on one side of the middle part of the tooling main body component two (304). Horizontal adjustment components (307) are provided on the top of both sides of the tooling main body component two (304).

6. The method for machining a forged fork tip mounting hole according to claim 5, characterized in that: The horizontal adjustment component (307) includes a base component two (3071), and a top cover fixing component two (3073) is bolted to the top of the base component two (3071). An adjusting screw component two (3072) is rotatably installed on the opposite side of the top cover fixing component two (3073) and the base component two (3071). A slider two (3074) is threaded to the outer side of the other end of the adjusting screw component two (3072). A compression spring adjusting component (3075) is provided on the top of the slider two (3074). The compression spring adjusting component (3075) is composed of a support block, a spring, and a compression spring bolt.

7. The method for machining a forged fork tip mounting hole according to claim 1, characterized in that: One end of the forged fork tip (5) has a heel end plane (501), one end of the forged fork tip (5) has a tail mounting hole (502), and both sides of one end of the forged fork tip (5) have fishtail spaces (503). One side of one end of the forged fork tip (5) is provided with a first flange (504), and the interior of the first flange (504) is provided with a plurality of flange mounting holes (505). One side of the other end of the forged fork tip (5) is provided with a second flange (510). The interior of the forged fork tip (5) has several two-flange mounting holes (511). One side of the middle part of the forged fork tip (5) is provided with a pull-down device groove (508). One side of the forged fork tip (5) is provided as a top surface (507). The other side of the forged fork tip (5) is provided as a bottom surface (506). The bottom surface (506) is provided with three base plate mounting grooves (509). The other end of the forged fork tip (5) is provided with a tip plane (512). The bottom of the forged fork tip (5) is provided with a reserve area (513).

8. The method for machining a forged fork tip mounting hole according to claim 7, characterized in that: The number of forging fork tips (5) is two, that is, two workpieces are clamped at one time, and all upper and lower clamping devices are shared.

9. A method for machining a forged fork tip mounting hole according to claim 1, characterized in that: The replaceable drill bit body (6) is a replaceable drill bit. Both the handle and the cutting tool are equipped with a center water outlet function, and it has Φ30.5 drill bit and φ25 drill bit specifications. The top of the replaceable drill bit body (6) is equipped with a replaceable alloy drill bit (601), and the top of the replaceable alloy drill bit (601) is provided with a drill bit angle (602).

10. A method for machining a forged fork tip mounting hole according to claim 1, characterized in that: In step S4, for each workpiece, the zero-point coordinates are defined in the program using different user-defined variable R values.

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