A clamping tool for a shaft box machining center

Abstract

The clamping tool for axle box machining center belongs to the technical field of axle box machining, comprising: a bottom plate horizontally installed on the machining center workbench through embedded screws, a cylindrical support vertically and fixedly connected to the middle position of the top surface of the bottom plate, the cylindrical support being arranged below the bottom end surface of the axle sleeve; a positioning ring coaxially and fixedly connected to the top of the cylindrical support, the outer diameter of the positioning ring being matched with the hole diameter of the bottom end of the turning shaft hole; a threaded pull rod fixedly connected at the root to the top surface of the cylindrical support and located inside the positioning ring, the top end of the threaded pull rod penetrating through the pull rod via hole of the gland plate and locked by a nut, both ends of the gland plate being crimped to the top end surface of the axle sleeve; a positioning column and a jackscrew, the two positioning columns being symmetrically arranged at the outer ends of the top surface of the bottom plate, the jackscrew being threadedly connected to the top of the positioning column, and the inner end of the jackscrew abutting against the back surface of the compression spring disc. The axle box semi-finished product to be turned can be quickly clamped onto the workbench, and the machining efficiency and machining quality are improved.

Description

Technical Field

[0001] This invention relates to the field of axle box machining technology, and in particular to a clamping fixture for an axle box machining center. Background Technology

[0002] The axle box is a key component of the railway freight car bogie. It is fitted onto the outer end of the wheelset axle, and cylindrical roller bearings are installed to support the axle, transferring the weight of the car body to the axle. It plays a crucial role in driving safety. Axle boxes are generally manufactured using a casting followed by machining process. The axle box casting billet first requires turning the end faces of the axle hole 102' and the axle sleeve 101'. Then, the semi-finished axle box 1' is... Figure 1 As shown, it is then moved to the machining center for milling of the circular groove 105' and the threaded hole platform 106'.

[0003] However, currently, there is no suitable tooling for milling the axle box semi-finished product 1' on the machining center. The semi-finished product 1' is cubicalized onto the machining center's worktable, and shims are used to elevate the end face of the axle sleeve 101'. A dial indicator is used to ensure that the two compression spring discs 104' are approximately at the same X-axis coordinate position, i.e., flush with the long side of the worktable. Then, multiple sets of pressure plates are used to fix the semi-finished product 1' onto the worktable. After fixing, the program is run to machine the circular groove 105' and the threaded hole platform 106'. This method of operation has low clamping and positioning accuracy, and the repeated dial indicator operation is complex, time-consuming, and labor-intensive. While it can meet the needs of processing single or small batches of products, it is not suitable for mass production of the axle box semi-finished product 1'.

[0004] To overcome the above problems, a clamping fixture for axle box machining center is needed. Summary of the Invention

[0005] The purpose of this invention is to provide a clamping fixture for axle box machining center, which can quickly clamp the semi-finished axle box after turning onto the worktable, thereby improving machining efficiency and machining quality.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: This invention provides a clamping fixture for an axle box machining center, used to clamp a semi-finished axle box that has been turned on the machining center, comprising: The base plate is horizontally installed onto the machining center workbench using pre-embedded screws. A cylindrical support is vertically fixed to the middle of the top surface of the base plate, and the cylindrical support is placed below the bottom end face of the axle sleeve. A positioning ring is coaxially fixedly connected to the top of the cylindrical support, and the outer diameter of the positioning ring is adapted to the diameter of the bottom end of the machined shaft hole; A threaded tie rod is fixedly connected at its root to the top surface of the cylindrical support and located inside the positioning ring. The top end of the threaded tie rod passes through the tie rod through hole of the pressure plate and is locked with a nut. Both ends of the pressure plate are pressed against the top surface of the axle sleeve. The positioning posts and the set screws are arranged symmetrically at the outer ends of the top surface of the base plate. The set screws are threaded to the top of the positioning posts, and the inner end of the set screws abuts against the back of the compression spring plate.

[0007] The actual use of the technical solution in this application shows that it greatly improves the clamping efficiency of the machining center process. At the same time, due to the good clamping and positioning, the machining center has sufficient machining allowance for milling round grooves and threaded hole platforms, ensuring the machining quality.

[0008] Furthermore, the axis of the cylindrical support coincides with the center line of the machining center table, and the positioning ring is fixedly connected to the top surface of the cylindrical support by multiple circumferentially distributed fastening screws.

[0009] Furthermore, a drainage groove is provided at the top of the side wall of the cylindrical support, and the inner end of the drainage groove extends into the inner side of the positioning ring.

[0010] Furthermore, there are two threaded tie rods, which are symmetrically arranged about the axis of the cylindrical support; the bottom end of the threaded tie rod is threaded into the threaded hole on the top surface of the cylindrical support and locked with a nut; the nut at the top of the threaded tie rod is pressed onto the cover plate by a thick washer.

[0011] Furthermore, the inner wall of the positioning column is provided with a clearance groove at the position of the bottom rib plate below.

[0012] Furthermore, a locking nut is threaded onto the set screw, and the locking nut is tightened onto the outer wall of the positioning column.

[0013] Furthermore, it also includes a precision alignment component, which is located at the top center of the cylindrical support, and the precision alignment component enables the turning shaft hole and the axis of the cylindrical support to be precisely aligned.

[0014] Furthermore, the precision alignment component includes a central pressure rod, top support bars, and a guide groove block. The central pressure rod includes a top rod, a truncated cone portion, and a threaded rod segment arranged coaxially from top to bottom. A central threaded hole is opened at the center of the top surface of the cylindrical support, and the threaded rod segment is threadedly connected to the central threaded hole. Multiple top support bars are circumferentially distributed around the periphery of the truncated cone portion and contact the conical surface of the truncated cone portion through inclined surfaces of the same angle. The guide groove block radially guides the top support bars, and the outer end of the top support bar protrudes from the radial guide hole below the positioning ring and can abut against the inner wall of the turning shaft hole.

[0015] Furthermore, the cross-section of the top support bar is rectangular, and the outer end of the top support bar is set as a semi-cylindrical head, with a chamfered edge on the top edge of the semi-cylindrical head.

[0016] Furthermore, the central pressure rod also includes a guide post portion, which is coaxially disposed between the truncated cone portion and the threaded rod segment; correspondingly, the top of the central threaded hole is provided with a guide circular hole that mates with the guide post portion.

[0017] By using the central pressure rod as the core component of the precision alignment assembly, a positioning relationship can be directly established between the cylindrical support and the axle hole of the workpiece, thus compensating for the influence of the assembly gap of the positioning ring.

[0018] Compared with the prior art, the beneficial technical effects of the present invention are as follows: This invention relates to a clamping fixture for axle box machining center. A cylindrical support top surface cushions the bottom end face of the axle sleeve, causing the bottom edge of the compression spring plate to move away from the top surface of the base plate. A locating ring centers and limits the bottom end of the machined shaft hole, achieving vertical positioning of the axle sleeve's axis. The positioning column and set screws allow adjustment of the swing angle of the compression spring plate around the axle sleeve's axis, controlling the distance between the inner wall of the positioning column and the back of the compression spring plate, thus leveling the two compression spring plates. Using a circular hole for centering, two set screws to prevent swaying, and threaded pull rods and pressure plates for height-direction clamping, the semi-finished axle box can be completely positioned and fixed onto the machining center's worktable. This clamping fixture for axle box machining center allows for rapid clamping of machined semi-finished axle boxes onto the worktable, improving machining efficiency and quality.

[0019] Furthermore, the positioning ring, secured with fastening screws, facilitates disassembly and installation. When the outer edge of the positioning ring deforms or wears, it can be replaced to ensure accurate positioning. A drainage groove is added to drain cutting fluid accumulated inside the positioning ring, preventing corrosion. Two threaded tie rods tighten the pressure plate, providing strong connection and evenly pressing the top surface of the axle sleeve. Adding support ribs increases the rigidity of the pressure plate, preventing deformation when tightening the nuts on the threaded tie rods. A positioning chamfer is used to position the pressure plate, preventing misalignment during clamping. A clearance groove prevents interference between the bottom rib plate and the positioning column during set screw adjustment. A locking nut on the set screw secures the adjusted set screw, preventing loosening due to machining vibrations and ensuring machining accuracy. By adding the precision alignment component at the top center of the cylindrical support, the assembly gap between the positioning ring and the bottom port of the machined shaft hole can be bridged, improving the mounting and positioning accuracy. The central pressure rod screws into the threaded section, causing the truncated cone to descend. The conical surface of the truncated cone pushes the top support bar outward. Guided by the guide groove and the radial guide hole, the top support bar can only be pushed out radially outward. The outer end of the top support bar abuts against the inner wall of the machined shaft hole, causing the machined shaft hole to disengage from the outer wall of the positioning ring and maintain a uniform gap, thus achieving precise alignment of the axis of the machined shaft hole and the cylindrical support. By setting the cross-section of the top support bar to a rectangle, rotation of the top support bar can be prevented. By setting the outer end of the top support bar to a semi-cylindrical head, point contact with the inner wall of the machined shaft hole can be formed, resulting in more precise positioning. By setting the top edge of the semi-cylindrical head to a chamfer, during the workpiece installation process, as the axle sleeve falls, the bottom port of the axle sleeve automatically presses the outer end of the top support bar inward, causing it to return to its original position. By adding a guide post and a guide hole, the working position of the central pressure rod is precisely aligned with the axis of the cylindrical support, avoiding the influence of the fit clearance between the threaded rod section and the central threaded hole, and preventing the central pressure rod from becoming skewed. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings.

[0021] Figure 1 A schematic diagram of the three-dimensional structure of a semi-finished axle box; Figure 2 This is a three-dimensional structural diagram of the mounting fixture for the axle box machining center of the present invention in its installed state; Figure 3 This is a three-dimensional structural diagram of the clamping fixture for the axle box machining center of the present invention; Figure 4 This is a schematic diagram of the three-dimensional structure of the pressure plate in this invention; Figure 5This is a cross-sectional view of the cylindrical support portion in another embodiment of the present invention; Figure 6 for Figure 5 A top-view structural diagram; Figure 7 for Figure 5 Enlarged schematic diagram of the central pressure bar mounting area.

[0022] Explanation of reference numerals in the attached drawings: 1', semi-finished axle box; 101', axle sleeve; 102', machined shaft hole; 103', bottom rib plate; 104', compression spring disc; 105', circular groove; 106', threaded hole platform; 1. Base plate; 2. Cylindrical support; 201. Drain groove; 202. Center threaded hole; 203. Guide hole; 204. Drain hole; 3. Positioning ring; 301. Fastening screw; 4. Threaded tie rod; 5. Positioning column; 501. Clearance groove; 6. Set screw; 601. Locking nut; 7. Pressure plate; 701. Tie rod through hole; 702. Support rib; 7021. Positioning chamfer; 703. Center rod through hole; 8. Center pressure rod; 801. Conical part; 802. Guide column part; 803. Threaded rod section; 804. Top rod; 805. Wrench part; 9. Top support bar; 901. Semi-cylindrical head; 10. Guide groove block; 11. Embedded screw. Detailed Implementation

[0023] The core of this invention is to provide a clamping fixture for axle box machining center, which can quickly clamp the semi-finished axle box after turning onto the worktable, thereby improving machining efficiency and machining quality.

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0026] Refer to the attached diagram. Figure 1 A schematic diagram of the three-dimensional structure of a semi-finished axle box; Figure 2This is a three-dimensional structural diagram of the mounting fixture for the axle box machining center of the present invention in its installed state; Figure 3 This is a three-dimensional structural diagram of the clamping fixture for the axle box machining center of the present invention; Figure 4 This is a schematic diagram of the three-dimensional structure of the pressure plate in this invention; Figure 5 This is a cross-sectional view of the cylindrical support portion in another embodiment of the present invention; Figure 6 for Figure 5 A top-view structural diagram; Figure 7 for Figure 5 Enlarged schematic diagram of the central pressure bar mounting area.

[0027] Example 1 In one specific implementation, such as Figures 1-4 As shown, the clamping fixture for the axle box machining center of the present invention is used to clamp the semi-finished axle box 1' after turning on the machining center. It requires positioning the workpiece using the bottom end face of the machined axle sleeve 101' and the machined shaft hole 102'. The clamping fixture for the axle box machining center of the present invention includes: The base plate 1, serving as the main supporting component, is horizontally mounted to the machining center worktable via pre-embedded screws 11. These pre-embedded screws 11 are T-head screws, installed on the machining center worktable through T-slots. A cylindrical support 2 is vertically fixed to the center of the top surface of the base plate 1. The cylindrical support 2 can be connected by welding or by tightening with countersunk screws with inverted bottoms. The cylindrical support 2 is positioned below the bottom end face of the axle sleeve 101', thus providing positioning support for the axle sleeve 101' portion of the workpiece.

[0028] The locating ring 3 is coaxially fixed to the top of the cylindrical support 2, and the outer diameter of the locating ring 3 is adapted to the diameter of the bottom end of the machined shaft hole 102'. When mounting the workpiece, the bottom end of the machined shaft hole 102' fits onto the outer periphery of the locating ring 3 to complete the centering of the circular hole.

[0029] The threaded tie rod 4 is fixedly connected at its root to the top surface of the cylindrical support 2 and located inside the positioning ring 3. The top end of the threaded tie rod 4 passes through the tie rod through hole 701 of the pressure plate 7 and is locked with a nut. The two ends of the horizontally set pressure plate 7 are pressed against the top surface of the axle sleeve 101'. The two ends of the pressure plate 7 are set as arc end faces.

[0030] Positioning posts 5 and set screws 6 are symmetrically arranged at the outer ends of the top surface of the base plate 1. That is, the bottom of the positioning posts 5 is directly welded to the top surface of the base plate 1 or connected by countersunk screws with inverted bottoms. The set screws 6 are threaded to the top of the positioning posts 5. The axial direction of the set screws 6 is set along the width direction of the machining center worktable, and the inner end of the set screws 6 abuts against the back of the compression spring plate 104'.

[0031] Specifically, such as Figure 2 and Figure 3 As shown, the positioning column 5 is a square column, and the threaded hole of the set screw 6 is thinned.

[0032] The cylindrical support 2 provides support to the bottom surface of the axle sleeve 101', causing the bottom edge of the spring plate 104' to move away from the top surface of the base plate 1. The positioning ring 3 centers and limits the bottom port of the machined shaft hole 102', achieving vertical positioning of the axle sleeve 101''s axis. The positioning column 5 and set screw 6 allow adjustment of the swing angle of the spring plate 104' around the axis of the axle sleeve 101', controlling the distance between the inner wall of the positioning column 5 and the back of the spring plate 104', thus leveling the two spring plates 104'. Using a circular hole for centering, two set screws 6 to prevent swaying, and threaded pull rod 4 and pressure plate 7 for height compression, the axle box semi-finished product 1' can be completely positioned and fixed onto the machining center worktable. This invention's axle box machining center clamping fixture can quickly clamp the machined axle box semi-finished product 1' onto the worktable, improving machining efficiency and quality.

[0033] In one specific implementation of this embodiment, such as Figure 3 As shown, the axis of the cylindrical support 2 coincides with the center line of the machining center's worktable, which facilitates programming and machining. The locating ring 3 is fixedly connected to the top surface of the cylindrical support 2 by multiple circumferentially distributed fastening screws 301. The top edge of the outer wall of the locating ring 3 is chamfered.

[0034] The positioning ring 3, which is fixed by fastening screw 301, is easy to disassemble and install. When the outer edge of the positioning ring 3 is deformed or worn, the positioning ring 3 can be replaced to ensure accurate positioning.

[0035] In one specific implementation of this embodiment, such as Figure 3 As shown, a water-draining groove 201 is provided at the top of the side wall of the cylindrical support 2, and the inner end of the water-draining groove 201 extends into the inner side of the positioning ring 3.

[0036] The addition of a drainage slot 201 allows for the discharge of cutting fluid that accumulates inside the positioning ring 3, preventing rust buildup.

[0037] In one specific implementation of this embodiment, such as Figure 2 and Figure 3 As shown, there are two threaded tie rods 4, symmetrically arranged about the axis of the cylindrical support 2. The bottom end of the threaded tie rod 4 is threaded into the threaded hole on the top surface of the cylindrical support 2 and locked with a nut. Correspondingly, there are also two tie rod through holes 701. The nut at the top of the threaded tie rod 4 is pressed against the top surface of the cover plate 7 by a thick washer.

[0038] Specifically, such as Figure 4As shown, the bottom surface of the cover plate 7 is provided with two support ribs 702 arranged along the long side, and the two support ribs 702 are symmetrically arranged at the center. The outer vertical edge of the end face of the support rib 702 is set as a positioning chamfer 7021, which is limited to the inner wall of the top opening of the turning shaft hole 102'.

[0039] Two threaded tie rods 4 are used to tighten the cover plate 7, providing high connection strength and evenly pressing the top surface of the axle sleeve 101'. The addition of support ribs 702 increases the rigidity of the cover plate 7, preventing deformation when tightening the nuts on the threaded tie rods 4. A positioning chamfer 7021 is used to position the cover plate 7 during installation, preventing it from shifting during the clamping process.

[0040] In one specific implementation of this embodiment, such as Figure 2 and Figure 3 As shown, the inner wall of the positioning column 5 has a clearance groove 501 at the position of the bottom rib plate 103'. The clearance groove 501 is an oblique groove with different depths on the left and right sides, which is adapted to the rounded corner part of the end of the bottom rib plate 103'.

[0041] By adding a clearance slot 501, interference between the lower bottom rib plate 103' and the positioning column 5 is avoided during the adjustment of the top screw 6.

[0042] Specifically, such as Figure 2 and Figure 3 As shown, a locking nut 601 is also threaded onto the set screw 6, and the locking nut 601 is tightened to the outer wall of the positioning column 5.

[0043] By adding a locking nut 601 to the set screw 6, the adjusted set screw 6 can be locked, preventing the set screw 6 from loosening due to the influence of processing vibration during the processing, which would affect the processing accuracy.

[0044] The process of using the clamping fixture for the axle box machining center of this invention is as follows: Open the machine cover of the machining center, and use a sling to pass through the two circular grooves 105' of the axle box semi-finished product 1', with both ends of the sling connected to the crane hooks above the axle sleeve 101'. Operate the crane and place the axle box semi-finished product 1' onto the cylindrical support 2. Note that the shaft hole 102' is machined from top to bottom and fitted onto the threaded tie rod 4. The bottom end of the axle sleeve 101' is fitted onto the positioning ring 3, and the bottom end face of the axle sleeve 101' contacts the top surface of the cylindrical support 2. Place the pressure plate 7, and fit the two tie rod through holes 701 onto the threaded tie rod 4 respectively. The two ends of the pressure plate 7 are pressed against the top surface of the axle sleeve 101'. Place the thick shim onto the threaded tie rod 4 and thread the nut, and manually tighten the nut. Manually adjust the set screw 6 so that its inner end abuts against the back of the spring plate 104', allowing the workpiece to swing slightly around the center of the cylindrical support 2. Use a depth gauge to measure the distance between the inner wall of the positioning column 5 and the back of the spring plate 104', ensuring that the distances at both ends are equal. Tighten the locking nut 601 with a wrench. Finally, tighten the nut on the threaded tie rod 4 with a wrench to complete the final positioning and fixing of the workpiece. Turn on the machining center, and the milling cutter will begin machining the circular groove 105' and the threaded hole platform 106'.

[0045] Example 2 In the above embodiment 1, only the locating ring 3 is used to center the bottom end of the machined shaft hole 102'. To facilitate mounting, an assembly gap inevitably exists between the two. Furthermore, the machined shaft hole 102' is machined on a conventional lathe, and its inner diameter also has certain machining errors. If the gap is large, for example, exceeding 0.3 mm, it will cause the behavioral tolerance between the bottom surface of the milled circular groove 105' and the machined shaft hole 102' to exceed the standard, resulting in defective products. Therefore, necessary measures need to be taken to reduce the impact of this mounting gap.

[0046] In one specific implementation of this embodiment, such as Figures 5-7 As shown, the mounting fixture for the axle box machining center of the present invention also includes a precision alignment component, which is set at the top center position of the cylindrical support 2. The precision alignment component enables the turning shaft hole 102' and the axis of the cylindrical support 2 to be precisely aligned.

[0047] By adding the precision alignment component at the top center of the cylindrical support 2, the assembly gap between the positioning ring 3 and the bottom port of the machined shaft hole 102' can be bridged, thus improving the mounting and positioning accuracy.

[0048] Obviously, the precise alignment component can also use an external clamping block for centering and internal support, similar to setting a three-jaw chuck on the top of the cylindrical support 2 for internal support. This method has a more complex structure and higher design and manufacturing costs. Similar implementation methods all fall within the protection scope of this invention.

[0049] In one specific implementation of this embodiment, such as Figures 5-7 As shown, the precise alignment component includes a central pressure rod 8, top support bars 9, and a guide groove block 10. The central pressure rod 8 includes a top rod 804, a truncated cone portion 801, and a threaded rod segment 803 arranged coaxially from top to bottom. A central threaded hole 202 is opened at the center of the top surface of the cylindrical support 2, and the threaded rod segment 803 is threadedly connected to the central threaded hole 202. Multiple top support bars 9 are evenly distributed around the periphery of the truncated cone portion 801 and contact the conical surface of the truncated cone portion 801 through inclined surfaces of the same angle. The inclined surfaces are set on the inner end faces of the top support bars 9, and the bottom surface of the top support bars 9 contacts the top surface of the cylindrical support 2. In a specific embodiment, there are three top support bars 9. The guide groove block 10 radially guides the top support bars 9, and the outer end of the top support bar 9 protrudes from the radial guide hole below the positioning ring 3 and can abut against the inner wall of the turning shaft hole 102'.

[0050] Specifically, such as Figure 5 As shown, the top of the push rod 804 passes upward through the central rod through hole 703 in the middle of the pressure plate 7, and a wrench part 805 is coaxially provided on the top of the push rod 804. The wrench part 805 is in the shape of a square prism and is compatible with an open-end wrench.

[0051] The cone section 801 descends as the central pressure rod 8 is screwed into the threaded rod section 803. The conical surface of the cone section 801 pushes the top support bar 9 outward. Under the guidance of the guide groove block 10 and the radial guide hole, the top support bar 9 can only be pushed out radially. The outer end of the top support bar 9 abuts against the inner wall of the machined shaft hole 102', so that the machined shaft hole 102' is disengaged from the outer wall of the positioning ring 3 and the gap remains uniform. This achieves precise alignment of the axis of the machined shaft hole 102' and the cylindrical support 2.

[0052] Specifically, such as Figures 5-7 As shown, the top support bar 9 has a rectangular cross-section, and the corresponding guide groove of the guide block 10 has a rectangular opening. The two ends of the guide groove block 10 are connected to the top surface of the cylindrical support 2 by screws. The outer end of the top support bar 9 is set as a semi-cylindrical head 901, and the top edge of the semi-cylindrical head 901 is provided with a chamfer.

[0053] By setting the cross-section of the top support bar 9 to a rectangle, rotation of the top support bar 9 can be prevented. By setting the outer end of the top support bar 9 to a semi-cylindrical head 901, point contact can be formed with the inner wall of the turning shaft hole 102', resulting in more precise positioning. By setting the top edge of the semi-cylindrical head 901 to a chamfer, during the workpiece installation process, as the axle sleeve 101' falls, the bottom port of the axle sleeve 101' automatically presses inward against the outer end of the top support bar 9, causing it to return to its original position.

[0054] In one specific implementation of this embodiment, such as Figure 5 and Figure 7 As shown, the central pressure rod 8 also includes a guide post portion 802, which is coaxially disposed between the frustum portion 801 and the threaded rod segment 803. A guide circular hole 203, which mates with the guide post portion 802, is provided at the top of the corresponding central threaded hole 202. Obviously, the diameter of the guide circular hole 203 is larger than that of the threaded rod segment 803 and smaller than the diameter of the lower end of the frustum portion 801.

[0055] By adding a guide post 802 and a guide hole 203, the working position of the central pressure rod 8 is precisely aligned with the axis of the cylindrical support 2, avoiding the influence of the fit clearance between the threaded rod section 803 and the central threaded hole 202, and preventing the central pressure rod 8 from becoming skewed.

[0056] The process of using the clamping fixture in the axle box machining center in this embodiment is as follows: Based on the above embodiment 1, after manually tightening the nut on the threaded pull rod 4, a wrench needs to be used to rotate the wrench part 805, which drives the central pressure rod 8 to be tightened into the central threaded hole 202. Under the guidance of the guide round hole 203, the cone part 801 descends vertically, and the conical surface of the cone part 801 pushes the top support bar 9 outward. Under the guidance of the guide groove block 10 and the radial guide hole, the top support bar 9 can only be pushed out radially outward. The outer end of the top support bar 9 abuts against the inner wall of the machined shaft hole 102', so that the machined shaft hole 102' is disengaged from the outer wall of the positioning ring 3 and the gap is kept uniform, thereby realizing the precise coincidence of the axis of the machined shaft hole 102' and the cylindrical support 2. After machining is completed, when disassembling the workpiece, before loosening the nut on the threaded tie rod 4, it is necessary to first use a wrench to turn the wrench part 805 to drive the center pressure rod 8 to loosen it two turns from the center threaded hole 202, so that the outer end of the top support bar 9 no longer presses against the inner side wall of the turning shaft hole 102', and then disassembly can be carried out.

[0057] In summary, the mounting fixture for the axle box machining center of the present invention supports the bottom end face of the axle sleeve 101' by using the top surface of the cylindrical support 2 to lift the bottom edge of the spring plate 104' away from the top surface of the base plate 1. The positioning ring 3 centers and limits the bottom end of the machined shaft hole 102', thus achieving vertical positioning of the axle sleeve 101's axis. By setting the positioning column 5 and the set screw 6, the swing angle of the spring plate 104' around the axis of the axle sleeve 101' can be adjusted. By controlling the distance between the inner side wall of the positioning column 5 and the back of the spring plate 104', the two spring plates 104' can be leveled. The use of a round hole for centering, two set screws 6 for anti-sway, and threaded tie rod 4 and pressure plate 7 for pressing in the height direction can completely position and fix the axle box semi-finished product 1' onto the machining center worktable. This invention provides a clamping fixture for axle box machining center, which can quickly clamp the semi-finished axle box 1' after turning onto the worktable, improving machining efficiency and quality. Furthermore, the positioning ring 3, fixed by fastening screws 301, is easy to disassemble and install. When the outer edge of the positioning ring 3 deforms or wears, it can be replaced to ensure accurate positioning. A drainage groove 201 is added to drain cutting fluid accumulated inside the positioning ring 3, preventing rust buildup. Two threaded tie rods 4 are used to tighten the pressure plate 7, providing high connection strength and evenly pressing the top surface of the axle sleeve 101'. The addition of supporting ribs 702 increases the rigidity of the pressure plate 7, preventing deformation when tightening the nuts on the threaded tie rods 4. A positioning chamfer 7021 is used to position the pressure plate 7 during installation, preventing displacement during the clamping process. By adding a clearance slot 501, interference between the lower bottom rib plate 103' and the positioning column 5 is avoided during the adjustment of the set screw 6. By adding a locking nut 601 to the set screw 6, the adjusted set screw 6 can be locked, preventing it from loosening due to machining vibration during processing, which would affect machining accuracy. By adding the precision alignment component at the top center of the cylindrical support 2, the assembly gap between the positioning ring 3 and the bottom end of the turned shaft hole 102' can be bridged, improving the mounting and positioning accuracy. The central pressure rod 8 is screwed into the threaded rod section 803, causing the truncated cone section 801 to descend. The conical surface of the truncated cone section 801 pushes the top support bar 9 outward. Guided by the guide groove block 10 and the radial guide hole, the top support bar 9 can only be pushed out radially outward. The outer end of the top support bar 9 abuts against the inner wall of the machined shaft hole 102', causing the machined shaft hole 102' to disengage from the outer wall of the positioning ring 3 and maintain a uniform gap, thereby achieving precise alignment of the axis of the machined shaft hole 102' and the cylindrical support 2. By setting the cross-section of the top support bar 9 to be rectangular, it is possible to prevent the top support bar 9 from rotating. By setting the outer end of the top support bar 9 to be a semi-cylindrical head 901, a point contact can be formed with the inner wall of the machined shaft hole 102', resulting in more accurate positioning.By setting the top edge of the semi-cylindrical head 901 to a chamfer, during the workpiece installation process, as the axle sleeve 101' falls, the bottom end of the axle sleeve 101' automatically presses inward against the outer end of the top support bar 9, causing it to return to its original position. The addition of a guide post 802 and a guide hole 203 ensures that the working position of the central pressure rod 8 precisely coincides with the axis of the cylindrical support 2, avoiding the influence of the clearance between the threaded rod section 803 and the central threaded hole 202, and preventing the central pressure rod 8 from becoming misaligned.

[0058] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0059] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A clamping fixture for an axle box machining center, used for clamping a semi-finished axle box (1') after turning on the machining center, characterized in that, include: The base plate (1) is horizontally installed on the machining center workbench by pre-embedded screws (11). A cylindrical support (2) is vertically fixed to the middle position of the top surface of the base plate (1). The cylindrical support (2) is placed below the bottom end face of the axle sleeve (101'). The positioning ring (3) is coaxially fixedly connected to the top of the cylindrical support (2), and the outer diameter of the positioning ring (3) is adapted to the diameter of the bottom end of the machined shaft hole (102'). The threaded pull rod (4) is fixedly connected at its root to the top surface of the cylindrical support (2) and located inside the positioning ring (3). The top end of the threaded pull rod (4) passes through the pull rod through hole (701) of the cover plate (7) and is locked with a nut. Both ends of the cover plate (7) are pressed against the top surface of the axle sleeve (101'). Positioning posts (5) and set screws (6) are provided. The two positioning posts (5) are symmetrically arranged at the outer ends of the top surface of the base plate (1). The set screws (6) are threaded to the top of the positioning posts (5). The inner end of the set screws (6) abuts against the back of the compression spring disc (104').

2. The clamping fixture for the axle box machining center according to claim 1, characterized in that: The axis of the cylindrical support (2) coincides with the center line of the machining center worktable, and the positioning ring (3) is fixedly connected to the top surface of the cylindrical support (2) by multiple circumferentially distributed fastening screws (301).

3. The clamping fixture for a shaft box machining center according to claim 2, characterized in that: A water-draining groove (201) is provided at the top of the side wall of the cylindrical support (2), and the inner end of the water-draining groove (201) extends into the inner side of the positioning ring (3).

4. The clamping fixture for a shaft box machining center according to claim 1, characterized in that: The number of threaded pull rods (4) is two and they are symmetrically arranged about the axis of the cylindrical support (2); the bottom end of the threaded pull rod (4) is threaded into the threaded hole on the top surface of the cylindrical support (2) and locked with a nut; the nut at the top of the threaded pull rod (4) is pressed onto the cover plate (7) by a thick washer.

5. The clamping fixture for a shaft box machining center according to claim 1, characterized in that: The inner wall of the positioning column (5) has a clearance groove (501) at the position of the bottom rib plate (103').

6. The clamping fixture for a shaft box machining center according to claim 1, characterized in that, A locking nut (601) is also threaded onto the set screw (6), and the locking nut (601) is tightened onto the outer wall of the positioning column (5).

7. The clamping fixture for a shaft box machining center according to claim 1, characterized in that: It also includes a precision alignment component, which is located at the top center of the cylindrical support (2) and enables the axis of the machined shaft hole (102') and the cylindrical support (2) to be precisely aligned.

8. The clamping fixture for a shaft box machining center according to claim 7, characterized in that: The precision alignment component includes a center pressure rod (8), a top support bar (9), and a guide groove block (10). The center pressure rod (8) includes a top rod (804), a truncated cone (801), and a threaded rod segment (803) arranged coaxially from top to bottom. A central threaded hole (202) is provided at the center of the top surface of the cylindrical support (2). The threaded rod segment (803) is threadedly connected to the central threaded hole (202). Multiple top support bars (9) are circumferentially distributed around the periphery of the truncated cone (801) and contact the conical surface of the truncated cone (801) through inclined surfaces of the same angle. The guide groove block (10) radially guides the top support bars (9). The outer end of the top support bar (9) protrudes from the radial guide hole below the positioning ring (3) and can abut against the inner wall of the turning shaft hole (102').

9. The clamping fixture for a shaft box machining center according to claim 8, characterized in that: The cross-section of the top support strip (9) is rectangular, and the outer end of the top support strip (9) is set as a semi-cylindrical head (901). The top edge of the semi-cylindrical head (901) is provided with a chamfer.

10. The clamping fixture for a shaft box machining center according to claim 8, characterized in that: The central pressure rod (8) also includes a guide post (802), which is coaxially disposed between the truncated cone (801) and the threaded rod segment (803); the corresponding central threaded hole (202) is provided with a guide circular hole (203) that cooperates with the guide post (802) at its top.

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