A stretching apparatus and method for tapered open drum shafts

Abstract

The present application belongs to the field of rotor shaft assembly, and particularly relates to a stretching device and method for a conical opening drum shaft. Due to the particularity of the structure of the drum shaft, the part itself does not have a threaded position for fixing with a traditional stretching tool, and the part itself is insufficient in rigidity to serve as a stretching force point. The present application has a positioning ring placed on a support, the positioning ring has uniformly spaced radial limiting structures inside; a top rod is connected with a nut after sequentially passing through an upper shaft sleeve and a lower shaft sleeve; the upper end of the upper shaft sleeve has a cavity structure, the middle part has an upper annular boss, the head of the top rod is limited below the cavity structure and has a stretching gap with the bottom, and a hydraulic cylinder is also accommodated in the cavity structure; the upper draw claw has a petal-shaped arc structure and has outer bosses at both ends, and the lower draw claw has a petal-shaped arc structure and has outer bosses at both ends. The floating positioning of the drum shaft and the casing is ensured, and the stretching work of the conical surface structure is realized through the device, and a breakthrough from nothing to something is completed.

Description

Technical Field

[0001] This invention belongs to the field of rotor shaft assembly, and specifically relates to a tensioning device and method for a tapered open drum shaft. Background Technology

[0002] The existing nut tensioning and tightening technology usually involves using a fixture to fix the lower bushing to be tensioned, then applying a tensile load through a tensioning machine after the fixture presses the force point. Once the tensile load reaches the design value, the nut is tightened. The entire tensioning process is relatively simple and is not limited by space. The process flow is generally as follows: preparation of workpiece and equipment → assembly of workpiece and tensioning fixture → installation of tensioning fixture and equipment → workpiece tensioning → nut tightening → measurement after tightening until the tension is qualified.

[0003] Due to the special structure of the drum shaft, its parts do not have threaded positions for fixing with traditional tensioning fixtures, and the parts themselves are not rigid enough to serve as tensioning force points. Therefore, traditional tensioning fixtures that use the workpiece itself as the force point for threaded fixing are not suitable for tensioning the drum shaft and cannot meet the requirements for tensioning and tightening nuts on the drum shaft. Summary of the Invention

[0004] This invention provides a stretching device and method for a tapered open drum shaft, which solves the problem that the drum shaft cannot be stretched using traditional stretching fixtures due to its structure, while also meeting the requirements for tightening the drum shaft nut.

[0005] This invention proposes a tensioning device for a conical open drum shaft. The device has a support in the middle of a base plate with stepped holes, and arc-shaped brackets supported on both sides of the support by pillars. A positioning ring is placed on the support, with a uniformly spaced radial limiting structure inside and symmetrically arranged positioning handles on the outside. A push rod passes through an upper and lower bushing and connects to a nut. The upper end of the upper bushing has a cavity structure with an upper annular boss in the middle. The head of the push rod is restricted to the lower side of this cavity structure and has a tension gap with the bottom. A hydraulic cylinder is also housed in the cavity structure, and the opening is sealed with a screw cap. The push rod has a large-diameter rod section and a small-diameter rod section. The upper pull claws have a petal-shaped arc structure with external bosses at both ends. Multiple upper pull claws encircle the upper bushing, and the upper end... The outer boss mates with the upper annular boss, is positioned by a cylindrical pin, and is clamped by a clamp with angular markings. The lower outer boss of the upper pull claw rests against the upper conical opening of the drum shaft. A ring-shaped wrench is fitted on the outside of the upper pull claw, with a plug at the bottom. The wrench is connected to a wrench head via a connecting rod. The lower bushing is fitted onto the small-diameter rod, and the lower bushing is pressed against the stepped surface of the rod by the nut. The lower bushing has a lower annular boss at its bottom. The lower pull claw has a petal-shaped arc structure with outer bosses at both ends. Multiple lower pull claws encircle the lower bushing and are separated by the radial limiting structure. The lower outer boss mates with the lower annular boss, is positioned by a cylindrical pin, clamped by a clamp, and then placed into the stepped hole of the support. The upper outer boss rests against the lower conical opening of the drum shaft.

[0006] Advantageously, the screw cap has an installation handle.

[0007] Advantageously, the actuating end of the hydraulic cylinder abuts against the head of the push rod.

[0008] Advantageously, a washer is also installed between the lower bushing and the nut.

[0009] Advantageously, the support is a ring structure, with its bottom mounted on a base plate by screws.

[0010] Advantageously, the upper end of the support column has an adjusting nut for adjusting the height of the arc-shaped bracket.

[0011] Advantageously, the rotation angle can be read by the position of the nut wrench.

[0012] Advantageously, the force-bearing bevels of the upper and lower pull claws are polished, the transition is grooved, and the sharp edges are rounded to avoid damage to the parts.

[0013] The present invention also proposes a stretching method for a conical open drum shaft, which employs the aforementioned stretching device and includes the following steps: Step 1: Insert the wrench head into the end hole of the workpiece nut; Step 2: Install multiple upper pull claws into the upper conical opening of the drum shaft in sequence and fit them together. Insert the upper shaft sleeve into the center of the upper pull claw. Connect the upper annular boss with the upper outer boss of the upper pull claw and position it with a cylindrical pin. Fix it with a clamp. Step 3: Install multiple pull-down claws into the lower tapered opening of the drum shaft in sequence and fit them together. Insert the lower shaft sleeve into the center of the pull-down claw. Connect the lower annular boss with the lower outer boss of the pull-down claw and position it with a cylindrical pin. Fix it with a clamp. Step 4: Pass the push rod through the upper and lower bushings and then connect it to the nut; Step 5: Install the hydraulic cylinder into the cavity structure, seal it with a screw cap and abut it against the head of the push rod; Step 6: Fit the positioning ring onto the outside of the pull-down claw and separate the pull-down claw using the radial limiting structure; Step 7: Install the entire assembly into the stepped hole of the support, and support the casing with the arc-shaped bracket; Step 8: Connect the hydraulic cylinder to the tensile testing machine, adjust the tensile load, and apply it; Step 9: Once the tensile load reaches the set value, adjust the torque wrench to the set torque, and rotate the wrench head to tighten the workpiece nut. Determine the rotation angle of the nut by checking the clamp markings.

[0014] Advantageously, the rotation angle of the workpiece nut needs to be greater than 8°.

[0015] Beneficial effects: This invention overcomes the limitations of the workpiece structure itself, which precludes the use of traditional center tie rod tensioning mechanisms, and breaks away from the traditional design concept of nut tightening tensioning fixtures. It ensures the floating positioning of the drum shaft and the casing, and simultaneously realizes the tensioning of the conical surface structure through this device, achieving a breakthrough from scratch. Attached Figure Description

[0016] Figure 1 This is a three-dimensional model diagram of the tensioning device for the drum shaft of the present invention; Figure 2 This is a cross-sectional view of the tensioning portion of the tensioning device for the drum shaft of the present invention. Figure 3 This is a cross-sectional view of the overall structure of the tensioning device for the drum shaft of the present invention.

[0017] 1—Top rod; 2—Upper bushing; 3—Threaded cap; 4—Mounting handle; 5—Clamp; 6—Arc-shaped bracket; 7—Cylindrical pin; 8—Upper pull claw; 9—Wrench head; 10—Connecting rod; 11—Wrench; 12—Lower pull claw; 13—Lower bushing; 14—Washer; 15—Nut; 16—Hydraulic cylinder; 17—Positioning handle; 18—Positioning ring; 19—Support; 20—Screw; 21—Base plate; 22—Support column; 23—Adjusting nut Detailed Implementation like Figure 1 and Figure 2 As shown, the upper bushing 2 has a hollow structure for housing the push rod 1 and the hydraulic cylinder 16. A screw cap 3 is used to fix the push rod 1 and the hydraulic cylinder 16. The screw cap 3 has a stepped boss that mates with the upper end face of the hydraulic cylinder 16 for positioning the hydraulic cylinder 16. A boss on the upper end of the push rod 1 mates with the lower end face of the hydraulic cylinder 16, working together with the screw cap 3 to position the hydraulic cylinder 16. A boss on the outer edge of the upper bushing 2 mates with the upper boss of the upper pull claw 8, and a cylindrical pin 7 is designed to position the upper pull claw 8. A clamp 5 is used to clamp the upper bushing 2 and the upper pull claw 8 to prevent axial separation. The lower end of the upper pull claw 8 is designed to meet the tapered surface of the upper end of the drum shaft. The corresponding conical surface of the device is used to apply tension force, which effectively prevents force transmission loss. Due to the limited space structure, the tightening process of the nut is transferred to the open space area by designing a wrench 11, a connecting rod 10, and a wrench head 9. The upper end of the pull claw 12 is designed to apply tension force by matching the conical surface of the lower end of the drum shaft. The lower end of the pull claw 12 has an outer edge protrusion similar to the lower bushing 13 for clamping and fixing. The device finally uses a washer 14 and a nut 15 to connect the lower bushing 13 to the push rod 1. The push rod 1 is designed with a stepped structure to match the upper end of the lower bushing 13 for force transmission.

[0018] like Figure 1 and Figure 3 As shown, the positioning ring 18 is designed with a three-lobed protruding limiting structure, which is used to cooperate with the three gaps of the pull claw 12. The positioning handle 17 is used to connect the positioning ring 18 to prevent the device from rotating. The base plate 21 is connected to the support 19 by screws 20. Two opening slots are designed to place the lower clamp, which plays a role in overall centering. The support column 22 is fixed on the base plate 21 and is used in conjunction with the arc bracket 6 and the adjusting nut 23 to support the outer casing of the drum shaft. The adjusting nut 23 can adjust the height of the arc bracket 6 through the thread, which indirectly adjusts the position of the outer casing of the drum shaft and prevents the outer casing from scratching the drum shaft.

[0019] The upper bushing 2 is installed on the tensile testing machine body via a screw cap 3, and is connected to one end of the upper pull claw 8 via a clamp 5. The other end of the upper pull claw 8 is connected to the conical surface of the drum shaft being stretched. The lower bushing 13 contacts the pressure head of the tensile testing machine, passes through the upper bushing 2 and the upper pull claw 8, and is connected to one end of the lower pull claw 12 via a clamp 5. The other end of the lower pull claw 12 is connected to the other end of the conical surface of the drum shaft being stretched. The support 19 is circumferentially positioned by the three grooves formed by the positioning ring 18 and the lower pull claw 12. A positioning handle 17 is installed on the support 19. A support column 22 and an arc-shaped bracket 6 extend from the support 19. The arc-shaped bracket 6 is fixed to the mounting edge of the casing of the part being stretched, ensuring the floating positioning of the drum shaft and the casing.

[0020] Both the upper pull claw 8 and the lower pull claw 12 are three-part separate structures, ensuring that they can be inserted into the narrow-diameter cavity of the stretched drum shaft, and that the lower bushing 13 can pass through the center of the upper pull claw 8 and the lower pull claw 12. The upper pull claw 8 and the upper bushing 2, and the lower pull claw 12 and the lower bushing 13 are circumferentially positioned and evenly distributed by cylindrical pins 7, thereby avoiding uneven force distribution and providing anti-rotation function.

[0021] The clamp 5 has angle markings, and the effective rotation angle of the tightened workpiece nut can be read by the position of the wrench 11.

[0022] The positioning ring 18 is installed in the groove of the support 19 and the pull claw 12. Meanwhile, the support 19 is connected to the casing through the support column 22 and the arc bracket 6, thereby realizing the floating positioning of the stretched drum shaft and the casing.

[0023] The method of using the tensioning device for the tapered open drum shaft is as follows: Step 1: Insert the wrench 11 into the end hole of the workpiece nut; Step 2: Insert the three-lobed upper pull claw 8 into the workpiece, ensuring that the tapered surface of the pull claw fits against the tapered surface of the workpiece. Insert the upper bushing 2 into the upper pull claw 8, align it with the upper pull claw 8, and position it using the cylindrical pin 7. Use the clamp 5 to fix the upper bushing 2 and the upper pull claw 8. Step 3: Insert the three-lobed pull-down claw 12 into the workpiece, ensuring that the cone surface of the pull-down claw fits against the cone surface of the other end of the workpiece. Pass the lower bushing 13 through the center of the pull-down claw 12 and position it with a cylindrical pin. Use the clamp 5 to fix the lower bushing 13 to the pull-down claw 12. Step 4: Pass the push rod 1 through the center of the upper bushing 2 and the lower bushing 13, and fix the other end with a washer 14 and a nut 15; Step 5: Install the hydraulic cylinder 16 into the upper bushing 2, and use the screw cap 3 to fix it to the push rod 1; Step 6: Install the positioning ring 18 and the three slots created by the pull-down claw 12 for circumferential positioning; Step 7: Install the assembled assembly into the support 19, and fix the arc-shaped bracket 6 to the casing by adjusting the adjusting nut 23; Step 8: Connect the hydraulic cylinder 16 to the tensile testing machine, adjust the tensile load to 258KN and apply the load; Step 9: After the load reaches the set value, use a torque wrench to adjust it to 145~155 N.m, and tighten the workpiece nut by using the wrench head 9. Step 10: After completion, read the rotation angle of the workpiece nut through the 5-mark line of the clamp. It is 10°, which meets the requirement of being greater than 8°.

Claims

1. A tensioning device for a conical open drum shaft, characterized in that: The device has a support (19) in the middle of the base plate (21), the support (19) has a stepped hole, and arc-shaped brackets (6) are supported on both sides of the support (19) by pillars (22); a positioning ring (18) is placed on the support (19), the positioning ring (18) has a radially limiting structure with uniform intervals inside, and a positioning handle (17) with symmetrical arrangement outside; the push rod (1) passes through the upper bushing (2) and the lower bushing (13) in sequence and then connects with the nut (15). Connection; the upper end of the upper bushing (2) has a cavity structure, and the middle part has an upper annular boss. The head of the push rod (1) is restricted to the lower side of the cavity structure and has a tension gap with the bottom. The cavity structure also accommodates a hydraulic cylinder (16), and the opening is sealed by a screw cap (3); the push rod (1) has a large-diameter rod part and a small-diameter rod part. The upper pull claw (8) is a petal-shaped arc structure and has an outer boss at both ends. Multiple upper pull claws (8) surround the upper bushing (2), and the upper end is outer The boss mates with the upper annular boss, is positioned by a cylindrical pin, and is clamped by a clamp (5). The clamp (5) has angular markings. The lower end of the upper pull claw (8) is attached to the upper conical opening of the drum shaft. A ring-shaped wrench (11) is fitted on the outside of the upper pull claw (8). The wrench (11) has a plug at the bottom and is connected to a wrench head (9) via a connecting rod (10). The lower bushing (13) is fitted on the small diameter rod. The lower bushing (13) is secured by the nut. (15) Pressed on the stepped surface of the rod; the bottom of the lower bushing (13) has a lower annular boss, the pull claw (12) is a petal-shaped arc structure, and has an outer boss at both ends. Multiple pull claws (12) surround the lower bushing (13) and are separated by the radial limiting structure. The lower outer boss is connected to the lower annular boss, positioned by a cylindrical pin, clamped by a clamp, and then placed in the stepped hole of the support (19). The upper outer boss is attached to the lower tapered opening of the drum shaft.

2. The tensioning device according to claim 1, characterized in that: The screw cap (3) has an installation handle (4).

3. The tensioning device according to claim 1, characterized in that: The actuating end of the hydraulic cylinder (16) abuts against the head of the push rod (1).

4. The tensioning device according to claim 1, characterized in that: A washer (14) is also installed between the lower bushing (13) and the nut (15).

5. The tensioning device according to claim 1, characterized in that: The support (19) is a ring structure, and its bottom is mounted on the base plate (21) by screws (20).

6. The tensioning device according to claim 1, characterized in that: An adjusting nut (23) is provided at the upper end of the support column (22) for adjusting the height of the arc-shaped bracket (6).

7. The tensioning device according to claim 1, characterized in that: The rotation angle is read by the position of the nut wrench.

8. The tensioning device according to claim 1, characterized in that: The upper pull claw (8) and lower pull claw (12) are polished with inclined surfaces, grooved at the transition, and rounded at the sharp edges to avoid damaging the parts.

9. A method for stretching a tapered open drum shaft, characterized in that: The method employs the tensioning device as described in any one of claims 1-8, and includes the following steps: Step 1: Insert the plug of the wrench (11) into the end hole of the workpiece nut; Step 2: Install multiple upper pull claws (8) into the upper conical opening of the drum shaft and fit them together. Insert the upper shaft sleeve (2) into the center of the upper pull claw (8). Connect the upper annular boss with the upper outer boss of the upper pull claw (8) and position it with a cylindrical pin. Fix it with a clamp. Step 3: Insert multiple pull-down claws (12) into the lower tapered opening of the drum shaft and fit them together. Insert the lower shaft sleeve (13) into the center of the pull-down claw (12). The lower annular boss aligns with the lower outer boss of the pull-down claw (12) and is positioned by a cylindrical pin. Use a clamp to fix it. Step 4: Pass the push rod (1) through the upper bushing (2) and the lower bushing (13) and then connect it to the nut (15); Step 5: Install the hydraulic cylinder (16) into the cavity structure, seal it with the screw cap (3) and abut it against the head of the push rod (1); Step 6: Fit the positioning ring (18) onto the outside of the pull-down claw (12) and separate the pull-down claw (12) by the radial limiting structure; Step 7: The entire assembly is inserted into the stepped hole of the support (19) and supported by the arc-shaped bracket (6); Step 8: Connect the hydraulic cylinder (16) to the tensile testing machine, adjust the tensile load and apply it; Step 9: When the tensile load reaches the set value, adjust the torque wrench to the set torque and rotate it through the wrench head (9) to tighten the workpiece nut. Determine the rotation angle of the nut by using the clamp markings.

10. The stretching method according to claim 9, characterized in that: The rotation angle of the workpiece nut must be greater than 8°.

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