Bolt elongation measuring tool

Abstract

The utility model relates to the technical field of measuring devices, in particular to a bolt elongation measuring tool which comprises a measuring sleeve, a measuring rod and a measuring plate, the measuring sleeve can abut against a bolt, a first through hole is formed in the measuring sleeve, and the measuring rod is slidably connected into the first through hole and can be inserted into the bolt; the first through hole comprises a limiting hole and a connecting hole, the limiting hole is communicated with the connecting hole, the diameter of the limiting hole is matched with that of the measuring rod, and the diameter of the connecting hole is larger than that of the limiting hole; the measuring plate is fixedly connected with the measuring rod, and a measuring piece used for measuring the distance between the measuring plate and the measuring sleeve is arranged between the measuring plate and the measuring sleeve. The measuring rod has the effect of facilitating installation of the measuring rod.

Description

Technical Field

[0001] The present application relates to the technical field of measuring devices, and in particular to a bolt elongation measuring tool. Background Art

[0002] In order to ensure the sealing force of the horizontal flange surface of the steam turbine and extend the service life of the bolts, the large bolts should be tightened by thermal tightening. The bolt pre-tightening stress generated by thermal tightening is based on the principle that the residual stress of the bolt is still greater than the required sealing stress after the unit has been running for 20,000 hours. Insufficient or excessive tightening force should be avoided. The force condition of the bolt can be accurately obtained by measuring the elongation of the bolt.

[0003] When measuring the elongation of a bolt, a bolt elongation measuring tool is used. The bolt elongation measuring tool usually includes a measuring sleeve, a measuring rod and a measuring plate. A fixing hole is provided on the flange, and the bolt is inserted into the fixing hole for limiting. A first through hole is provided on the bolt, and a second through hole is provided on the measuring sleeve. The measuring sleeve is installed on the bolt, and the first through hole and the second through hole are coaxially arranged. The measuring rod is inserted into the first through hole from the second through hole, and the measuring plate is fixed to the end of the measuring rod away from the measuring sleeve. When the bolt is elongated, the measuring sleeve is pushed to move, thereby reducing the distance between the measuring plate and the measuring sleeve. By measuring the change in the distance between the measuring plate and the measuring sleeve, the elongation of the bolt is obtained.

[0004] In order to reduce the shaking of the measuring rod in the first through hole and the second through hole, the measuring rod needs to be adapted to the inner diameter of the first through hole or the second through hole, which will increase the difficulty of installing the measuring rod during the process of inserting the measuring rod into the first through hole and the second through hole. Utility Model Content

[0005] The purpose of the present application is to provide a bolt elongation measuring tool, which facilitates the installation of a measuring rod.

[0006] The bolt elongation measurement tool provided in this application adopts the following technical solution:

[0007] A bolt elongation measuring tool comprises a measuring sleeve, a measuring rod and a measuring plate, wherein the measuring sleeve can abut against the bolt, a first through hole is formed on the measuring sleeve, and the measuring rod is slidably connected in the first through hole and can be inserted into the bolt;

[0008] The first through hole includes a limiting hole and a connecting hole, the limiting hole is connected to the connecting hole, the aperture of the limiting hole is adapted to the aperture of the measuring rod, and the aperture of the connecting hole is larger than the aperture of the limiting hole;

[0009] The measuring plate is fixedly connected to the measuring rod, and a measuring member for measuring the distance between the measuring plate and the measuring sleeve is arranged between the measuring plate and the measuring sleeve.

[0010] By adopting the above technical solution, by setting a limit hole and a connecting hole, the limit hole limits the position of the measuring rod, and the aperture of the connecting hole is larger than the aperture of the limit hole, so that there is a distance between the inner wall of the connecting hole and the outer wall of the measuring rod, thereby reducing the contact area between the first through hole and the measuring rod, reducing the friction between the measuring rod and the first through hole, and facilitating the installation of the measuring rod.

[0011] Optionally, the measuring rod is integrally formed.

[0012] A common measuring rod is formed by splicing multiple rods in sequence into a long rod. However, the long rod formed by multiple splicing is prone to position deviation during disassembly and assembly, resulting in low accuracy. By adopting the above technical solution, the measuring rod is integrally formed and does not need to be spliced ​​multiple times, thereby reducing the position deviation caused by the splicing process, thereby increasing the measuring accuracy of the measuring rod and the measuring accuracy of the bolt elongation measuring tool.

[0013] Optionally, the outer diameters of the measuring rods along their axial directions are all the same.

[0014] The machining of measuring rods is usually carried out on both sides of a lathe at the same time. However, since the measuring rod itself is relatively long and thin, it is easy to cause the measuring rod to bend during the machining process. By adopting the above technical solution, the outer diameter of the measuring rod along its axial direction is the same, and the measuring rod can be machined using a centerless grinding process, reducing the machining difficulty of the measuring rod.

[0015] Optionally, one end of the measuring rod is provided with a thread, and the measuring plate is threadedly connected to the measuring rod.

[0016] By adopting the above technical solution, the measuring plate and the measuring rod are threadedly connected, which facilitates the separate processing and transportation of the measuring rod and the measuring plate. During measurement, the measuring plate and the measuring rod are not disassembled throughout the whole process, thereby reducing the introduction of position deviation.

[0017] Optionally, it also includes a screw plug, which can be fixed on the bolt. When the measuring rod is inserted into the bolt, the measuring rod can abut against the screw plug.

[0018] By adopting the above technical solution and setting a screw plug, the measuring rod is limited to prevent the measuring rod from moving further downward, thereby facilitating the positioning of the measuring rod.

[0019] Optionally, a spherical surface is provided at one end of the measuring rod close to the screw plug.

[0020] If the end of the measuring rod that contacts the plug is a plane, when the flatness of the plane is insufficient, the contact position between the measuring rod and the plug may change due to the rotation of the measuring rod. By adopting the above technical solution and setting a spherical surface, the measuring rod and the plug are in point contact, which reduces the possibility of changes in the contact point between the measuring rod and the plug, thereby increasing the accuracy of the bolt elongation measuring tool.

[0021] Optionally, the outer diameter of the measuring sleeve is matched with the inner diameter of the mounting hole, and the mounting hole can limit the shaking of the measuring sleeve.

[0022] By adopting the above technical solution, the outer diameter of the measuring sleeve is matched with the inner diameter of the mounting hole, thereby reducing the position deviation of the measuring sleeve during the measurement process and further improving the measurement accuracy of the bolt elongation measuring tool.

[0023] Optionally, the measuring member is detachably connected to the measuring plate.

[0024] By adopting the above technical solution, measuring pieces of different measuring ranges can be replaced according to different bolt elongations, thereby increasing the applicable scope of the bolt elongation measuring tool.

[0025] In summary, the present application includes at least one of the following beneficial technical effects:

[0026] 1. By setting the limiting hole and the connecting hole, the limiting hole limits the position of the measuring rod, and the aperture of the connecting hole is larger than the aperture of the limiting hole, so that there is a gap between the inner wall of the connecting hole and the outer wall of the measuring rod, thereby reducing the contact area between the first through hole and the measuring rod, reducing the friction between the measuring rod and the first through hole, and facilitating the installation of the measuring rod;

[0027] 2. The measuring rod is formed in one piece, eliminating the need for multiple splicing, thereby reducing the position deviation caused by the splicing process, thereby increasing the measuring accuracy of the measuring rod and the bolt elongation measuring tool;

[0028] 3. If the outer diameter of the measuring rod along its axis is the same, the measuring rod can be processed using the centerless grinding process to reduce the processing difficulty of the measuring rod;

[0029] 4. According to the different elongation of the bolt, replace the measuring parts with different ranges to increase the applicable range of the bolt elongation measuring tool. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the cross-sectional structure of a bolt elongation measuring tool according to an embodiment of the present application.

[0031] Figure 2 yes Figure 1 A partial enlarged schematic diagram of part A.

[0032] In the figure, 1, bolt body; 11, second through hole; 12, fixing groove; 13, threaded hole;

[0033] 2. Flange; 21. Fixing hole; 22. Scrape surface;

[0034] 3. Cover nut; 31. Mounting hole;

[0035] 4. Measuring sleeve; 41. First through hole; 411. Limiting hole; 412. Connecting hole;

[0036] 5. Measuring rod; 51. Spherical surface;

[0037] 6. Screw plug;

[0038] 7. Measuring board;

[0039] 8. Measuring parts;

[0040] 9. Socket seat. DETAILED DESCRIPTION

[0041] The following is combined with Figure 1 -Attached Figure 2 , further details of this application are given.

[0042] A bolt, see Figure 1 , comprising a bolt body 1, the bolt body 1 is provided with a second through hole 11, the second through hole 11 is provided along the axial direction of the bolt body 1, and the center line of the second through hole 11 coincides with the center line of the bolt body 1. Figure 1 Taking perspective as an example, a fixing groove 12 is opened at the upper end of the bolt body 1, the fixing groove 12 is connected to the second through hole 11, the center line of the fixing groove 12 coincides with the center line of the second through hole 11, and the inner diameter of the fixing groove 12 is larger than the inner diameter of the second through hole 11; a threaded hole 13 is opened at the lower end of the bolt body 1, the center line of the threaded hole 13 coincides with the center line of the second through hole 11, and the threaded hole 13 is connected to the second through hole 11.

[0043] A flange. In an embodiment of the present application, flange 2 is an upper and lower flange, and a fixing hole 21 is provided on flange 2. In this embodiment, one section of the fixing hole 21 is a smooth hole, and the other section is a threaded hole. The bolt is inserted into the fixing hole 21 and cooperates with the thread of the threaded hole, so that the bolt is fixed in the fixing hole 21.

[0044] A cover nut 3 is provided on the bolt, which is installed on the flange 2 and screwed on the bolt to fix and limit the bolt. In this embodiment, a scraping surface 22 is provided on the top surface of the flange 2. In this embodiment, the cover nut 3 is threadedly connected to the bolt body 1 and can be inserted into the scraping surface 22.

[0045] A bolt elongation measuring tool includes a measuring sleeve 4, a mounting hole 31 is formed through a cover nut 3, the center line of the mounting hole 31 coincides with the center line of a fixing groove 12, and the measuring sleeve 4 is inserted into the mounting hole 31 and the fixing groove 12 and abuts against the bottom wall of the fixing groove 12. In this embodiment, in order to reduce the deviation of the measurement result caused by the shaking of the measuring sleeve 4, the outer diameter of the measuring sleeve 4 is adapted to the inner diameter of the mounting hole 31, that is, after the measuring sleeve 4 is inserted into the mounting hole 31, the outer peripheral wall of the measuring sleeve 4 is in contact with the inner peripheral wall of the mounting hole 31, thereby limiting the shaking of the measuring sleeve 4.

[0046] Reference Figure 1 and Figure 2 The measuring sleeve 4 is provided with a first through hole 41, which is provided along the axis of the measuring sleeve 4, the center line of the first through hole 41 coincides with the center line of the second through hole 11, and the first through hole 41 is connected with the second through hole 11. The bolt elongation measuring tool further includes a measuring rod 5, which is inserted into the first through hole 41 and simultaneously inserted into the second through hole 11.

[0047] In order to facilitate the insertion of the measuring rod 5, the first through hole 41 includes a limiting hole 411 and a connecting hole 412. The inner diameter of the limiting hole 411 is smaller than the inner diameter of the connecting hole 412, and the inner diameter of the limiting hole 411 is adapted to the outer diameter of the measuring rod 5, that is, when the measuring rod 5 is inserted into the limiting hole 411, the outer peripheral wall of the measuring rod 5 fits with the inner peripheral wall of the limiting hole 411. When the measuring rod 5 is inserted into the connecting hole 412, there is a gap between the outer peripheral wall of the measuring rod 5 and the inner peripheral wall of the connecting hole 412, so that when the measuring rod 5 is inserted into the first through hole 41, only the inner peripheral wall of the limiting hole 411 contacts the measuring rod 5, reducing the friction between the measuring rod 5 and the inner wall of the first through hole 41, and facilitating the insertion of the measuring rod 5.

[0048] The bolt elongation measuring tool further includes a screw plug 6, which is inserted into the threaded hole 13 and fixedly connected to the bolt body 1 through the threaded hole 13. When the measuring rod 5 is inserted into the second through hole 11, the measuring rod 5 abuts against the screw plug 6, thereby limiting the movement of the measuring rod 5. In order to ensure the accuracy of the entire bolt elongation measuring tool, the flatness of one side of the screw plug 6 close to the measuring rod 5 is not greater than 0.02 mm. In this embodiment, the flatness of one side of the screw plug 6 close to the measuring rod 5 is 0.02 mm.

[0049] A spherical surface 51 is provided at one end of the measuring rod 5 close to the screw plug 6. After the measuring rod 5 is inserted into the second through hole 11, the spherical surface 51 abuts against the screw plug 6, reducing the possibility of the position of the measuring rod 5 changing due to uneven contact surfaces, thereby ensuring the measurement accuracy of the bolt elongation measuring tool.

[0050] In this embodiment, the overall diameter of the measuring rod 5 is the same and the diameter of the spherical surface 51 is smaller than the diameter of the measuring rod 5, that is, the outer diameter of the measuring rod 5 along its axial direction is the same, and the entire measuring rod 5 is in the shape of a cylindrical rod, so that the measuring rod 5 can be processed using a centerless grinding process, thereby reducing the processing difficulty of the measuring rod 5.

[0051] The bolt elongation measuring tool also includes a measuring plate 7, which is mounted on one end of the measuring rod 5 away from the measuring sleeve 4. In this embodiment, a thread is provided at one end of the measuring rod 5 connected to the measuring plate 7, and the measuring plate 7 is threadedly connected to the measuring rod 5, and the outer diameter of this end is smaller than the outer diameter of the rest of the measuring rod 5. A sleeve seat 9 is fixedly sleeved on the top of the measuring sleeve 4. Before installing the measuring sleeve 4, the sleeve seat 9 needs to be fixed on the measuring sleeve 4. A measuring piece 8 for measuring the distance between the sleeve seat 4 and the measuring plate 7 is provided between the sleeve seat 9 and the measuring plate 7, that is, the measuring piece 8 can measure the distance between the measuring sleeve 4 and the measuring plate 7. The measuring piece 8 is detachably connected to the measuring plate 7. In this embodiment, the measuring piece 8 can be placed on the measuring plate 7 to achieve detachable connection. In other embodiments, other methods can also be used to achieve detachable connection of the measuring piece 8.

[0052] In this embodiment, the measuring member 8 is a depth micrometer, and in other embodiments, the measuring member 8 may also be a depth vernier caliper. In this embodiment, by replacing the measuring member 8 with different measuring ranges, the applicable range of the bolt elongation measuring tool is increased.

[0053] The implementation principle of the embodiment of the present application is as follows: when installing the bolt elongation measuring tool, first place the bolt in the fixing hole 21, screw the cover nut 3 on the bolt and insert the cover nut 3 into the scraping surface 22, insert the measuring sleeve 4 into the mounting hole 31 and into the fixing groove 12, first screw the measuring plate 7 on the measuring rod 5, then insert the measuring rod 5 from the first through hole 41, insert it into the second through hole 11 and abut against the screw plug 6, and finally install the measuring piece 8 on the measuring plate 7 to complete the installation of the bolt elongation measuring tool. During the entire bolt measurement process, the measuring plate 7 and the measuring rod 5 are not allowed to be disassembled to reduce the introduction of position deviation.

[0054] Before cold tightening the bolt, first measure the distance between the measuring plate 7 and the sleeve seat 9. After the bolt is hot tightened and cooled to room temperature, measure the distance between the measuring plate 7 and the sleeve seat 9 again. The difference between the two measured distances is the elongation distance of the bolt.

[0055] The embodiments of this specific implementation are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. The same components are represented by the same figure marks. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A bolt elongation measuring tool, characterized in that: The measuring sleeve (4) comprises a measuring sleeve (4), a measuring rod (5) and a measuring plate (7), wherein the measuring sleeve (4) can abut against a bolt, a first through hole (41) is formed on the measuring sleeve (4), and the measuring rod (5) is slidably connected in the first through hole (41) and can be inserted into the bolt; The first through hole (41) comprises a limiting hole (411) and a connecting hole (412), the limiting hole (411) is connected to the connecting hole (412), the aperture of the limiting hole (411) is adapted to the aperture of the measuring rod (5), and the aperture of the connecting hole (412) is larger than the aperture of the limiting hole (411); The measuring plate (7) is fixedly connected to the measuring rod (5), and a measuring piece (8) for measuring the distance between the measuring plate (7) and the measuring sleeve (4) is provided between the measuring plate (7) and the measuring sleeve (4).

2. A bolt elongation measuring tool according to claim 1, characterized in that: The measuring rod (5) is integrally formed.

3. A bolt elongation measuring tool according to claim 1, characterized in that: The outer diameters of the measuring rods (5) along their axial direction are all the same.

4. A bolt elongation measuring tool according to claim 1, characterized in that: One end of the measuring rod (5) is provided with a thread, and the measuring plate (7) is threadedly connected to the measuring rod (5).

5. A bolt elongation measuring tool according to claim 1, characterized in that: It also comprises a screw plug (6), which can be fixed on the bolt, and when the measuring rod (5) is inserted into the bolt, the measuring rod (5) can abut against the screw plug (6).

6. A bolt elongation measuring tool according to claim 5, characterized in that: A spherical surface (51) is provided at one end of the measuring rod (5) close to the screw plug (6).

7. A bolt elongation measuring tool according to claim 1, characterized in that: The outer diameter of the measuring sleeve (4) can be matched with the inner diameter of the mounting hole (31) on the cover nut (3), and the mounting hole (31) can limit the shaking of the measuring sleeve (4).

8. A bolt elongation measuring tool according to claim 1, characterized in that: The measuring piece (8) is detachably connected to the measuring plate (7).

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