A jig for piezoelectric ceramic bonding of a bolt

Abstract

The present application belongs to the technical field of ultrasonic pre-tightening force detection of bolts, and particularly relates to a clamp for piezoelectric ceramic pasting of bolts. The clamp comprises a table clamp base, a clamping device and a piezoelectric ceramic pasting pressure maintaining device. The table clamp base bears the clamping function on the workbench, the clamping device bears the bolt clamping function, and the piezoelectric ceramic pasting pressure maintaining device bears the pressure maintaining function after piezoelectric ceramic pasting. The clamp provided by the present application is convenient to use, has strong adaptability to bolts of different sizes, and has the advantages of stable and reliable clamping and pressure maintaining.

Description

Technical Field

[0001] This invention belongs to the field of ultrasonic preload testing technology for bolts, and particularly relates to a clamp for bonding piezoelectric ceramics to bolts. Background Technology

[0002] Bolted connections are a common type of connection in mechanical structures. In some precision equipment, it is necessary to measure the preload of each bolt in bolted connections. To facilitate the measurement of bolt preload in bolted connections, a recess is machined on the top of the bolt, and piezoelectric ceramic is attached there. By using ultrasonic measurement, the bolt preload can be directly measured.

[0003] When machining bolts or attaching piezoelectric ceramics, the bolts need to be clamped vertically, and the piezoelectric ceramics need to be held under pressure. However, common clamping devices perform well in the horizontal direction but poorly in the vertical direction. To meet the pressure holding requirement, the clamps usually need to be used in conjunction with other devices, which is quite complex.

[0004] Existing bolt clamps have the following problems: 1) Poor clamping effect. Common clamps are effective at clamping bolts horizontally, but their effectiveness is poor when clamping them vertically, depending on the bolt's size. This is especially true for longer bolts, where interference from the clamp's bottom mechanism can prevent the bolt head from contacting the clamp's horizontal surface, severely impacting the clamping effect.

[0005] 2) When maintaining pressure on piezoelectric ceramics, traditional fixtures need to be operated in conjunction with other devices, which is complicated, costly and inefficient. Summary of the Invention

[0006] To address the problems existing in current bolt clamps, the purpose of this invention is to provide a clamp for bonding piezoelectric ceramics to bolts. This clamp offers excellent clamping performance and adaptability to multiple sizes, enabling stable vertical clamping of bolts or cylindrical workpieces of varying dimensions. Simultaneously, it provides a convenient pressure-holding function during piezoelectric ceramic bonding. This invention is simple to install and operate, stable and reliable in use, and can significantly improve the efficiency and quality of piezoelectric ceramic bonding.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A clamp for bonding piezoelectric ceramics to bolts comprises a table clamp base, a clamping device, and a piezoelectric ceramic bonding and pressure holding device. The overall structure is compact, and the components work together to achieve convenient use.

[0008] The aforementioned table clamp base is the foundation of the clamp, securing it to the workbench. The table clamp base consists of upper and lower parts, table clamp bolts, and table clamp chucks. By changing the relative installation positions of the two parts, it can accommodate workbenches of different thicknesses; the table clamp chucks are used for clamping.

[0009] The clamping device is the core component of the fixture, its function being to clamp bolts vertically. The main body consists of two bases, one on the left and one on the right, integrated with upper and lower cover plates. A lead screw is mounted between the bases and can be rotated by turning a knob. A lead screw nut is mounted on the lead screw, converting the rotation of the lead screw into linear motion of the nut. Two clamping arms are mounted on the lead screw nut at their ends, and the clamping arms are connected between the upper and lower cover plates via a shaft. The linear motion of the lead screw nut on the lead screw drives the clamping arms to rotate around the shaft, completing the clamping and loosening of the bolt. A clamping block is mounted at the front end of the clamping arms, increasing the clamping contact area between the fixture and the bolt or workpiece. A V-shaped block is mounted between the upper and lower cover plates, its function being to position the bolt and, in conjunction with the clamping arms, complete the bolt clamping.

[0010] The piezoelectric ceramic bonding and pressure-holding mechanism is designed to press the piezoelectric ceramic firmly. A column serves as the main support, and a crossbeam is connected to the column by screws. A groove at the connection point allows for horizontal adjustment based on the actual position of the piezoelectric ceramic on the bolt or workpiece. A pressure rod is installed at the end of the crossbeam and can move up and down within it. A pressure head and spring are installed on the underside of the pressure rod; the spring compression completes the pressure holding of the piezoelectric ceramic.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: The clamp provided by this invention is simple to operate, stable and reliable, and has excellent clamping effect and adaptability to multiple sizes of clamped objects. It can stably clamp bolts or cylindrical workpieces of different sizes in the vertical direction. For bolts, it can be used with various specifications of bolts, and there are no restrictions on bolt length. At the same time, it can realize a convenient pressure-holding function when bonding piezoelectric ceramics. Using bolt locking and spring compression, the pressure applied to the piezoelectric ceramics can be maintained for a long time to ensure the bonding quality of the piezoelectric ceramics and ultimately ensure the accuracy of ultrasonic preload detection. Attached Figure Description

[0012] Figure 1 This is a three-dimensional schematic diagram of a clamp for bonding piezoelectric ceramics to bolts according to the present invention.

[0013] Figure 2 This is a front view (with a partial sectional view) of a clamp for attaching piezoelectric ceramics to bolts according to the present invention.

[0014] Figure 3 This is a side sectional view of a clamp for bonding piezoelectric ceramics to bolts according to the present invention.

[0015] Figure 4 This is a top sectional view (with partial sectional view) of a clamp for bonding piezoelectric ceramics to bolts according to the present invention.

[0016] In the diagram: 1. Upper cover plate; 2. Lower cover plate; 3. First base; 4. Second base; 5. Lead screw nut; 6. Lead screw; 7. Shaft; 8. Clamping block; 9. Lead screw knob; 10. First clamping arm; 11. Second clamping arm; 12. V-block; 13. Pressure rod; 14. Crossbeam; 15. Spring; 16. Column; 17. Pressure head; 18. Upper part of table clamp; 19. Table clamp bolt; 20. Lower part of table clamp; 21. Table clamp chuck. Detailed Implementation

[0017] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and technical solutions.

[0018] like Figure 1-4 As shown, a piezoelectric ceramic bonding fixture for bolts according to the present invention includes a table clamp base, a clamping device, and a piezoelectric ceramic bonding and pressure holding mechanism; The table clamp base includes an upper table clamp portion 18, a lower table clamp portion 20, a table clamp bolt 19, and a table clamp head 21. Both the upper table clamp portion 18 and the lower table clamp portion 20 are L-shaped plate structures, arranged vertically opposite each other. The upper table clamp portion 18 is inverted so that the sides of the two are in contact. The sides are connected by the table clamp bolt 19. The space formed between the upper table clamp portion 18 and the lower table clamp portion 20 is used to accommodate the edge of the workbench. The horizontal part of the lower table clamp portion 20 is provided with a threaded mounting hole for the table clamp head 21 to pass through. By adjusting the position of the table clamp head 21, the workbench is clamped between the upper surface of the table clamp head 21 and the lower surface of the horizontal part of the upper table clamp portion 18, thereby fixing the entire clamp on the workbench.

[0019] The upper part 18 and the lower part 20 of the table clamp are provided with multiple corresponding positioning holes at their side joints. The distance between the upper part 18 and the lower part 20 of the table clamp can be adjusted by adjusting the connection between the table clamp bolt 19 and different positioning holes, thereby meeting the installation requirements of different workbench sizes.

[0020] The main body of the table clamp 21 is a threaded column. A shim is provided at the top of the threaded column. The upper surface of the shim is in contact with the lower surface of the workbench. A knob is provided at the bottom. By adjusting the position of the threaded column in the vertical direction by turning the knob, the table clamp 21 can be moved up and down, thereby adjusting the height of the shim.

[0021] A layer of foam is adhered to the lower surface of the horizontal portion of the table clamp 18 to provide cushioning.

[0022] The clamping device includes an upper cover plate 1, a lower cover plate 2, a first base 3, a second base 4, a lead screw 6, a first clamping arm 10, and a second clamping arm 11. The first base 3 and the second base 4 are arranged symmetrically from left to right. The upper cover plate 1 and the lower cover plate 2 are respectively fixed to the upper and lower surfaces of the first base 3 and the second base 4, thereby fixing the first base 3 and the second base 4 into one unit. The space formed between the upper cover plate 1 and the lower cover plate 2 is used to install the lead screw 6 and the first clamping arm 10 and the second clamping arm 11. Two lead screw nuts 5 are symmetrically installed on the lead screw 6. The front of the upper cover plate 1 and the lower cover plate 2... The end extends forward, and two shafts 7 are provided on the extension section. The top and bottom ends of the shafts 7 are connected to the lower surface of the upper cover plate 1 and the upper surface of the lower cover plate 2, respectively. The ends of the first clamping arm 10 and the second clamping arm 11 are respectively installed on two lead screw nuts 5. The middle of the first clamping arm 10 and the second clamping arm 11 are provided with through holes. The shafts 7 are installed through the through holes. The linear movement of the lead screw nut 5 on the lead screw 6 drives the first clamping arm 10 and the second clamping arm 11 to rotate around the shaft 7 to complete the tightening and loosening of the bolts. The upper surface of the horizontal part of the table clamp 18 is fixedly connected to the lower surface of the lower cover plate 2.

[0023] One end of the lead screw 6 is provided with a lead screw knob 9. By rotating the lead screw knob 9, the rotation of the lead screw 6 is converted into the linear motion of the lead screw nut 5.

[0024] The first clamping arm 10 and the second clamping arm 11 are equipped with clamping blocks 8 at their front ends, thereby increasing the clamping contact area between the clamp and the bolt.

[0025] A V-shaped iron 12 is installed between the extensions of the upper cover plate 1 and the lower cover plate 2. The V-shaped iron 12 is located between the first clamping arm 10 and the second clamping arm 11. Its function is to position the bolt and cooperate with the first clamping arm 10 and the second clamping arm 11 to clamp the bolt.

[0026] The piezoelectric ceramic bonding and pressure holding mechanism includes a column 16, a crossbeam 14, a pressure rod 13, and a pressure head 17. The column 16 is the main support body, and its bottom is fixed to the upper surface of the upper cover plate 1. One end of the crossbeam 14 is installed on the top of the column 16, and the pressure rod 13 is installed vertically on the other end. The pressure head 17 is installed at the bottom of the pressure rod 13, and the pressure head 17 is located directly above the front end of the first clamping arm 10 and the second clamping arm 11.

[0027] The crossbeam 14 has a through-slot. The crossbeam 14 is installed on the top of the column 16 by screws engaging with the slot. The horizontal position is adjusted according to the actual position of the piezoelectric ceramic strain gauge on the bolt.

[0028] The crossbeam 14 has a threaded hole on one side for mounting the pressure rod 13, which communicates with the mounting hole for mounting the pressure rod 13. The threaded hole is used to install bolts and nuts. By tightening the bolts and nuts, the pressure rod 13 is fixed on the crossbeam 14. By adjusting the position of the pressure rod 13 in the mounting hole of the crossbeam 14, the height of the pressure head 17 is adjusted.

[0029] The lower part of the pressure rod 13 is provided with a vertical through hole, in which a spring 15 is installed. The upper part of the pressure head 17 is located in the through hole, and the top of the pressure head 17 is in contact with the spring 15. The pressure head 17 is in contact with the piezoelectric ceramic strain gauge to be pasted. The piezoelectric ceramic strain gauge is pressed and pasted by the extension and retraction of the spring 15.

[0030] The implementation steps of this invention are as follows: 1) Fixture fixing stage. Before tightening the bolts, the fixture must be fixed. According to the size of the worktable, adjust the table clamp bolt 19 to the position of the positioning hole, adjust the appropriate distance between the upper part 18 and the lower part 19 of the table clamp, place the edge of the worktable between the upper part 18 and the lower part 20 of the table clamp, tighten the table clamp chuck 21 so that the table clamp chuck 21 is pressed against the bottom surface of the worktable, and complete the rigid fixing of the fixture on the worktable to ensure that there is no shaking or displacement during the subsequent clamping and pressure holding process.

[0031] 2) Bolt positioning and clamping stage. The bolt is placed vertically between the V-shaped iron 12 and the two clamping blocks 8, and the V-shaped iron 12 completes the initial radial positioning. By rotating the screw knob 9 clockwise, the screw 6 is rotated, and the screw nut 5 moves linearly along the screw 6, driving the first clamping arm 10 and the second clamping arm 11 to rotate in opposite directions around the axis 7. The clamping blocks 8 gradually clamp the outer wall of the bolt, achieving vertical clamping without off-center load.

[0032] 3) Piezoelectric ceramic bonding and pressure holding stage. After the bolt is clamped, apply adhesive to the recess on the top of the bolt and bond the piezoelectric ceramic. Loosen the screws and adjust the height and horizontal position of the crossbeam 14 on the column 16 to align the clamping block 8 with the center of the piezoelectric ceramic, ensuring vertical pressure. Adjust the position of the pressure rod 13 downwards to compress the spring 15, making the pressure head 17 tightly adhere to the surface of the piezoelectric ceramic; utilize the elastic restoring force of the spring 15 to apply constant and uniform pressure to the piezoelectric ceramic, achieving long-term pressure holding to ensure the adhesive layer is fully cured and firmly bonded. After the adhesive layer is completely cured, lift the pressure rod 13, the spring 15 returns to its original position, and the pressure head 17 detaches from the piezoelectric ceramic; loosen the screws, remove the crossbeam 14, and the bolt can be removed.

[0033] 4) Bolt loosening stage. Rotate the lead screw knob 9 counterclockwise, the lead screw nut 5 moves in the opposite direction, the first clamp arm 10 and the second clamp arm 11 rotate in opposite directions around the shaft 7, the clamp block 8 loosens the bolt, and the bolt is removed.

Claims

1. A clamp for bonding piezoelectric ceramics to bolts, characterized in that, The piezoelectric ceramic bonding fixture for the bolts includes a table clamp base, a clamping device, and a piezoelectric ceramic bonding and pressure holding mechanism; The table clamp base includes an upper part (18), a lower part (20), a table clamp bolt (19), and a table clamp head (21). The upper part (18) and the lower part (20) are both L-shaped plate structures, arranged vertically opposite each other. The upper part (18) is inverted so that the sides of the two parts are in contact. The sides are connected by the table clamp bolt (19). The space formed between the upper part (18) and the lower part (20) is used to accommodate the edge of the workbench. The horizontal part of the lower part (20) is provided with a threaded mounting hole for the table clamp head (21) to pass through. By adjusting the position of the table clamp head (21), the workbench is clamped between the upper surface of the table clamp head (21) and the lower surface of the horizontal part of the upper part (18), thereby fixing the entire clamp on the workbench. The clamping device includes an upper cover plate (1), a lower cover plate (2), a first base (3), a second base (4), a lead screw (6), a first clamping arm (10), and a second clamping arm (11). The first base (3) and the second base (4) are arranged symmetrically on the left and right. The upper cover plate (1) and the lower cover plate (2) are respectively fixed to the upper and lower surfaces of the first base (3) and the second base (4), thereby fixing the first base (3) and the second base (4) into one unit. The space formed between the upper cover plate (1) and the lower cover plate (2) is used to install the lead screw (6) and the first clamping arm (10) and the second clamping arm (11). Two lead screw nuts (5) are symmetrically installed on the lead screw (6). The upper cover plate (1) and the lower cover plate (2) are arranged symmetrically on the lower base (4). The front end of the cover plate (2) extends forward, and two shafts (7) are provided on the extension section. The top and bottom ends of the shafts (7) are connected to the lower surface of the upper cover plate (1) and the upper surface of the lower cover plate (2) respectively. The ends of the first clamping arm (10) and the second clamping arm (11) are respectively installed on two screw nuts (5). The middle part of the first clamping arm (10) and the second clamping arm (11) is provided with through holes. The shafts (7) are installed through the through holes. The linear movement of the screw nut (5) on the screw (6) drives the first clamping arm (10) and the second clamping arm (11) to rotate around the shaft (7) to complete the tightening and loosening of the bolts. The upper surface of the horizontal part of the table clamp (18) is fixedly connected to the lower surface of the lower cover plate (2). The piezoelectric ceramic bonding and pressure holding mechanism includes a column (16), a crossbeam (14), a pressure rod (13), and a pressure head (17); the column (16) is the main support body, and its bottom is fixed to the upper surface of the upper cover plate (1); one end of the crossbeam (14) is installed on the top of the column (16), and the pressure rod (13) is installed vertically on the other end; the pressure head (17) is installed at the bottom of the pressure rod (13), and the pressure head (17) is located directly above the front end of the first clamping arm (10) and the second clamping arm (11).

2. The piezoelectric ceramic bonding fixture for bolts according to claim 1, characterized in that, The upper part (18) and lower part (20) of the table clamp are provided with multiple corresponding positioning holes at their side joints. The distance between the upper part (18) and lower part (20) of the table clamp can be adjusted by adjusting the connection between the table clamp bolt (19) and different positioning holes, so as to meet the installation of different workbench sizes.

3. The piezoelectric ceramic bonding fixture for bolts according to claim 1, characterized in that, The main body of the table clamp (21) is a threaded column. A shim is provided on the top of the threaded column. The upper surface of the shim is in contact with the lower surface of the workbench. A knob is provided at the bottom. By adjusting the position of the threaded column in the vertical direction through the knob, the table clamp (21) can be moved up and down, thereby adjusting the height of the shim.

4. The piezoelectric ceramic bonding fixture for bolts according to claim 1, characterized in that, A layer of foam is pasted on the lower surface of the horizontal part of the table clamp (18) to provide cushioning.

5. The piezoelectric ceramic bonding fixture for bolts according to claim 1, characterized in that, One end of the lead screw (6) is provided with a lead screw knob (9). By rotating the lead screw knob (9), the rotation of the lead screw (6) is converted into the linear motion of the lead screw nut (5).

6. The piezoelectric ceramic bonding fixture for bolts according to claim 1, characterized in that, The first clamping arm (10) and the second clamping arm (11) are equipped with clamping blocks (8) at their front ends, thereby increasing the clamping contact area between the clamp and the bolt.

7. The piezoelectric ceramic bonding fixture for bolts according to claim 1, characterized in that, A V-shaped iron (12) is installed between the extensions of the upper cover plate (1) and the lower cover plate (2). The V-shaped iron (12) is located between the first clamping arm (10) and the second clamping arm (11). Its function is to complete the positioning of the bolt and cooperate with the first clamping arm (10) and the second clamping arm (11) to complete the clamping of the bolt.

8. The piezoelectric ceramic bonding fixture for bolts according to claim 1, characterized in that, The crossbeam (14) has a through-slot. The crossbeam (14) is installed on the top of the column (16) by screws and the through-slot. The horizontal position is adjusted according to the actual position of the piezoelectric ceramic strain gauge on the bolt.

9. A clamp for bonding piezoelectric ceramics to bolts according to claim 1, characterized in that, The crossbeam (14) has a threaded hole on one side for mounting the pressure rod (13), which is connected to the mounting hole for mounting the pressure rod (13). The threaded hole is used to install bolts and nuts. By tightening the bolts and nuts, the pressure rod (13) is fixed on the crossbeam (14). By adjusting the position of the pressure rod (13) in the mounting hole of the crossbeam (14), the height of the pressure head (17) is adjusted.

10. A clamp for bonding piezoelectric ceramics to bolts according to claim 1, characterized in that, The lower part of the pressure rod (13) is provided with a vertical through hole, and a spring (15) is installed in the through hole. The upper part of the pressure head (17) is located in the through hole. The top of the pressure head (17) is in contact with the spring (15). The pressure head (17) is in contact with the piezoelectric ceramic strain gauge to be pasted. The piezoelectric ceramic strain gauge is pressed and pasted by the extension and retraction of the spring (15).

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