A kind of finishing hole welding deformation prevention expansion mechanism

Abstract

The utility model provides a kind of anti-welding deformation tensioning mechanism for finish machining hole, belong to finish machining frock technical field.The mechanism is mainly used to solve the problem of hole diameter out-of-tolerance and hole wall pollution caused by heat deformation and spatter intrusion of finish machining hole in welding process.The technical scheme includes shaft center, shaft sleeve, conical sleeve, locking nut and gasket;Shaft center is provided with conical transition part, shaft sleeve inner hole is conical cooperation with it and outer wall is provided with alternate cutting line to realize radial expansion;Conical sleeve is conical cooperation with the other end of shaft sleeve, and shaft sleeve is bidirectional symmetrical expansion in hole by locking nut pre-tightening.Its beneficial effect is: effectively resist welding thermal deformation, keep hole diameter tolerance, prevent spatter from entering, avoid secondary processing, improve assembly accuracy and production efficiency.

Description

Technical Field

[0001] This utility model relates to the field of precision machining tooling technology, and in particular to a tensioning mechanism for preventing welding deformation in precision machining holes. Background Technology

[0002] In the manufacturing and assembly of structural components for engineering machinery, certain mounting holes often require precision machining before welding to meet assembly accuracy requirements. However, when the weld is located close to a pre-machined hole, the high-temperature heat effect generated during welding causes the hole wall to expand upon heating and contract upon cooling, resulting in dimensional deviations in the hole diameter and severely impacting subsequent assembly quality. Furthermore, welding spatter can easily penetrate the hole, forming weld slag residue, further affecting the hole wall smoothness and dimensional accuracy.

[0003] Currently, the industry commonly uses protective plugs or simple end caps to seal the machined holes to prevent spatter from entering. However, these methods only provide basic spatter prevention and cannot effectively suppress the impact of welding thermal deformation on the hole diameter. After welding, the deformed holes often still need to be re-grinded or reamed, which not only increases process time and production costs but may also lead to hole position deviations due to uneven grinding, affecting the assembly accuracy and service life of the overall structural component.

[0004] Therefore, there is an urgent need for a high-efficiency tooling mechanism that can effectively protect the hole from spatter contamination during the welding process, and suppress thermal deformation and ensure hole diameter tolerance through mechanical constraints, in order to solve the shortcomings of the existing technology. Utility Model Content

[0005] The purpose of this invention is to overcome the problems in the prior art and provide a tensioning mechanism for preventing welding deformation in precision-machined holes.

[0006] To achieve the above-mentioned utility model objectives, the present utility model adopts the following technical solution: a tensioning mechanism for preventing welding deformation in precision-machined holes, comprising a shaft, a bushing, a tapered sleeve, a locking nut, and a washer;

[0007] The shaft includes a handle, a transition section, and a connecting section. The transition section has a tapered structure, and the connecting section has a cylindrical structure. The end away from the transition section is provided with a stepped section and an external thread section in sequence.

[0008] The inner hole of the bushing is taperedly fitted to the transition part of the shaft, and the outer diameter of the bushing is expandable and contractible.

[0009] The tapered sleeve is taperedly fitted to the other end of the bushing;

[0010] The locking nut is threadedly connected to the shaft.

[0011] The gasket is located between the lock nut and the tapered sleeve;

[0012] The transition portion of the shaft and the tapered sleeve are symmetrically arranged about the center of the shaft sleeve. After installation, they work together to tighten the inner wall of the machined hole, thereby effectively resisting the deformation of the hole wall caused by welding thermal stress and preventing welding spatter from entering the hole.

[0013] Furthermore, the sidewall of the bushing is provided with axially distributed cutting lines, including a first cutting line and a second cutting line. The first cutting line extends from one end of the bushing to the other end, and the second cutting line extends from the other end of the bushing to the first end. The first and second cutting lines are distributed alternately. This structure enables the bushing to generate uniform radial elastic deformation when subjected to axial pressure, so as to adapt to different hole diameters and provide stable tension force, effectively suppressing hole shrinkage caused by welding heat.

[0014] Furthermore, the cutting line is a through groove or slit, which causes the bushing to expand radially under axial pressure, further enhancing its fit and support stability within the hole, reducing local stress concentration, and ensuring uniform stress on the hole wall.

[0015] Furthermore, the conical surface of the conical sleeve mates with the inner conical surface of the bushing to form a two-way conical clamping structure. This achieves a more balanced tensioning effect through bidirectional symmetrical force application, avoiding mechanism skewing and bore shape deviation caused by unilateral force application.

[0016] Furthermore, the gasket is a flat gasket or a spring gasket, used to distribute the pressure of the locking nut, prevent local damage to the tapered sleeve, and maintain the long-term stability of the preload, ensuring that the mechanism is always in a reliable tensioned state throughout the welding process.

[0017] Furthermore, the diameter of the connecting part is larger than that of the step, the diameter of the step is larger than that of the external thread section, and the diameter of the step matches the inner hole of the tapered sleeve. This is used to limit the forward distance of the tapered sleeve and the locking nut, prevent the tapered sleeve from being excessively pressed into the bushing and causing jamming, and facilitate disassembly after welding.

[0018] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0019] 1. The anti-welding deformation tensioning mechanism of this utility model forms a uniform and stable radial support force in the precision-machined hole through the conical surface fit of the shaft, bushing, and tapered sleeve, as well as the pre-tightening effect of the locking nut, effectively resisting thermal stress deformation during the welding process. Its bidirectional symmetrical tensioning structure can significantly reduce hole diameter deviations caused by uneven heating of the hole wall, ensuring that the precision fit dimensions still meet tolerance requirements after welding, avoiding subsequent tedious grinding or reaming processes, and improving production efficiency and product qualification rate.

[0020] 2. This mechanism features a compact and rational structure, facilitating easy assembly and disassembly. The axial cutting line design on the outer side of the bushing provides excellent elastic deformation capability, allowing it to adapt to different hole diameters and achieve reliable tightening. Simultaneously, the device completely seals the hole opening during welding, effectively preventing spatter from entering the hole, protecting the surface quality and cleanliness of the hole wall, reducing cleaning costs and assembly risks. It is particularly suitable for the high-precision protection requirements of near-hole welding in engineering machinery structural components. Attached Figure Description

[0021] The accompanying drawings are provided to further understand the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation thereof.

[0022] Figure 1 This is a schematic diagram of the structure of this utility model.

[0023] Figure 2 This is a schematic diagram of the explosive structure of this utility model. Figure 1 .

[0024] Figure 3 This is a schematic diagram of the explosive structure of this utility model. Figure 2 .

[0025] Figure 4 This is a structural schematic diagram of an embodiment of the present utility model.

[0026] The reference numerals in the attached drawings are as follows: 1. Shaft; 1.1. Hand-held part; 1.2. Transition part; 1.3. Connecting part; 2. Bushing; 3. Tapered sleeve; 4. Locking nut; 5. Washer; 6. Cutting line; 7. Stage; 8. External thread section. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this utility model clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. Of course, the specific embodiments described herein are merely illustrative of this utility model and are not intended to limit its scope. The utility model comprises five core components: bushing 2, tapered sleeve 3, locking nut 4, and washer 5. These components are precisely fitted together to achieve the functions of preventing deformation and splashing.

[0028] The shaft 1 is the core force transmission and operating component of the mechanism, preferably made of high-strength alloy steel through precision machining, possessing good rigidity and wear resistance. The shaft 1 sequentially includes a handle 1.1, a transition section 1.2, and a connecting section 1.3. The handle 1.1 can be designed as a hexagonal head structure or knurled, facilitating force application with a general-purpose wrench or manual operation. The transition section 1.2 is a precision conical surface, preferably with a taper of 1:10, which serves as the main working surface for converting axial tensile force into radial expansion force. The connecting section 1.3 is a cylinder, with a stepped section 7 and an external thread section 8 sequentially at its end, with the diameter relationship being: connecting section 1.3 > stepped section 7 > external thread section 8. The diameter of the stepped section 7 precisely matches the inner hole of the tapered sleeve 3, effectively limiting the axial movement of the tapered sleeve 3 and the locking nut 4, preventing the tapered sleeve 3 from being excessively pressed into the shaft sleeve 2 and causing jamming, greatly facilitating disassembly after welding.

[0029] The bushing 2 is a key elastic component for achieving radial expansion. It is made of 65Mn spring steel through heat treatment and tempering, possessing excellent elasticity and fatigue strength. Its outer diameter is designed according to the basic dimensions and tolerance zone of the precision-machined hole to be protected. Several cutting lines 6 are machined axially on the sidewall of the bushing 2. These cutting lines include a first cutting line extending from one end to the middle and a second cutting line extending from the other end to the middle, which are evenly distributed alternately. The cutting lines 6 can be in the form of slots or notches. This design allows the bushing 2 to undergo uniform and controllable radial elastic expansion like an elastic chuck when subjected to axial pressure, thereby tightly fitting the hole wall and resisting shrinkage deformation caused by welding thermal stress.

[0030] The tapered sleeve 3 is made of alloy steel, and its inner hole is a tapered hole that mates with the outer tapered surface of one end of the bushing 2. It and the transition part 1.2 of the shaft 1 are arranged symmetrically about the center of the bushing 2, forming a two-way tapered clamping structure. This structure ensures that the tension force is symmetrically transmitted and distributed from the middle of the hole to both ends, avoiding the mechanism from deflecting within the hole, and ensuring the stability of the support and the shape accuracy of the hole.

[0031] The washer 5 is a standard 65Mn spring washer, placed between the lock nut 4 and the tapered sleeve 3. Its function is to prevent the lock nut 4 from loosening under severe vibration, maintain the long-term stability of the preload, and at the same time distribute the nut pressure to protect the end face of the tapered sleeve 3 from being crushed.

[0032] The locking nut 4 is a high-strength nut that matches the external thread section 8 of the shaft 1 and is used to provide the final axial locking force.

[0033] How to use:

[0034] 1. Installation steps

[0035] Preparation: Ensure the precision-machined hole is clean and free of oil, burrs, and foreign objects. Select a tensioning mechanism of appropriate specifications based on the hole diameter.

[0036] Insert the shaft: Hold the hexagonal head of the shaft 1 and insert the connecting part 1.3 into one end (end A) of the workpiece hole until the thread at the end of the shaft is fully exposed from the other end (end B) of the hole.

[0037] Inserting the bushing: From end B, place the bushing 2 onto the connecting part 1.3 of the shaft 1 and gently push it into the hole. You can use a copper rod or wooden mallet to gently tap the end face of the bushing 2 to make it slide inward along the tapered transition part 1.2 of the shaft 1 until its outer circle initially fits against the hole wall.

[0038] Install the tapered sleeve and shim: Slide the tapered sleeve 3 onto end B, ensuring its inner tapered surface mates with the corresponding outer tapered surface of the bushing 2. Then install the shim 5 at the rear end of the tapered sleeve 3.

[0039] Tightening and locking: First, manually pre-tighten the locking nut 4, then use a wrench to fix the hexagonal head at the front end of the shaft 1, and then use another wrench to tighten the locking nut 4 according to the experienced torque value. At this time, the bushing 2 will generate radial expansion under the compression of the bidirectional conical surface until it is evenly tightened in the hole.

[0040] Status Confirmation: Check and confirm that the entire mechanism is evenly tightened inside the hole, with no looseness.

[0041] 2. Welding Operation: The workpiece can be welded according to normal procedures. The rigid support formed by this mechanism inside the hole effectively suppresses deformation caused by welding thermal stress, while its metal body completely seals the orifice, reliably preventing the intrusion of welding spatter.

[0042] The workpiece can be welded according to normal procedures. The rigid support formed by this mechanism inside the hole effectively suppresses deformation caused by welding thermal stress, while its metal body completely seals the orifice, preventing welding spatter from entering.

[0043] 3. Disassembly steps:

[0044] Operation after cooling: The workpiece and mechanism can only be disassembled after they have completely cooled to room temperature.

[0045] Loosen the nut: Use a wrench to loosen and remove the lock nut 4, and remove the washer 5.

[0046] Removal Mechanism: Gently tap the end face of the tapered sleeve 3 from end B with a soft tool to disengage it from the bushing 2. Subsequently, the bushing 2 elastically contracts and separates from the bore wall. Remove the tapered sleeve 3 and bushing 2 sequentially from side B, and finally pull out the shaft 1 from side A.

[0047] Cleaning and inspection: Check the cleanliness of the hole and measure the hole diameter to confirm that the dimensions meet the requirements.

[0048] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A tensioning mechanism for preventing welding deformation in precision-machined holes, characterized in that, It includes a shaft (1), a bushing (2), a tapered sleeve (3), a lock nut (4), and a washer (5); The shaft (1) includes a hand-held part (1.1), a transition part (1.2) and a connecting part (1.3). The transition part (1.2) is a tapered structure, and the connecting part (1.3) is a cylindrical structure. The end away from the transition part (1.2) is provided with a stepped section (7) and an external thread section (8) in sequence. The inner hole of the bushing (2) is taperedly fitted with the transition part (1.2) of the shaft (1), and the outer diameter of the bushing (2) is expandable and contractible. The tapered sleeve (3) is taperedly fitted to the other end of the bushing (2); The locking nut (4) is threadedly connected to the shaft (1) at the connection part (1.3); The gasket (5) is located between the locking nut (4) and the tapered sleeve (3); The transition part (1.2) of the shaft (1) and the tapered sleeve (3) are symmetrically arranged about the center of the shaft sleeve (2), and together they support the inner wall of the machining hole after installation.

2. The anti-welding deformation tensioning mechanism according to claim 1, characterized in that, The sidewall of the bushing (2) is provided with cutting lines (6) along the axial direction. The cutting lines (6) include a first cutting line and a second cutting line. The first cutting line extends from one end of the bushing (2) to the other end, and the second cutting line extends from the other end of the bushing (2) to that end. The first cutting line and the second cutting line are distributed alternately.

3. The anti-welding deformation tensioning mechanism according to claim 2, characterized in that, The cutting line (6) is a through groove or cut, which causes the bushing (2) to expand radially under axial pressure.

4. The anti-welding deformation tensioning mechanism according to claim 1, characterized in that, The conical surface of the conical sleeve (3) engages with the inner conical surface of the bushing (2) to form a two-way conical clamping structure.

5. The anti-welding deformation tensioning mechanism according to claim 1, characterized in that, The gasket (5) is a flat gasket or a spring gasket.

6. The anti-welding deformation tensioning mechanism according to claim 1, characterized in that, The diameter of the connecting part (1.3) is greater than that of the platform stage (7), the diameter of the platform stage (7) is greater than that of the external thread section (8), and the diameter of the platform stage (7) matches the inner hole of the tapered sleeve (3) to limit the forward distance of the tapered sleeve (3) and the locking nut (4).

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