Automatic pressure relief limiting hydraulic telescopic piece and bolt hydraulic stretcher

Abstract

The automatic pressure relief limiting hydraulic telescopic piece comprises a cylinder sleeve ring, a piston ring and a pressure relief piece, the cylinder sleeve ring and the piston ring are both vertically arranged, the piston ring is coaxially arranged in the cylinder sleeve ring, an annular gap is formed between the piston ring and the cylinder sleeve ring, and the pressure relief piece is arranged in the cylinder sleeve ring. The lower end of the cylinder sleeve ring is provided with an inner flange in sealing contact with the piston ring, the upper end of the piston ring is provided with an outer flange in sealing contact with the cylinder sleeve ring so that the annular gap can be defined to form an annular cavity, the outer wall of the cylinder sleeve ring is provided with a hydraulic opening communicated with the bottom end of the annular cavity, and the pressure relief piece is arranged on the outer wall of the cylinder sleeve ring. The side wall of the cylinder sleeve ring is further provided with a pressure relief flow channel communicated with the pressure relief piece, when the piston ring moves upwards relative to the cylinder sleeve ring till the annular cavity is communicated with the pressure relief flow channel, pressure relief is conducted, the upward sliding stroke of the piston ring is limited, the structure is simple, use is convenient, meanwhile, the limiting function is achieved when the piston ring extends, and therefore safety is good.

Description

Technical Field

[0001] This utility model belongs to the field of bolt tensioning technology, and in particular relates to an automatic pressure relief and limiting hydraulic telescopic component and a bolt hydraulic tensioner. Background Technology

[0002] Hydraulic tensioners are suitable for various applications involving bolt tightening, including pipe flanges, heat exchangers, pressure vessels, compressor covers, boiler feed pumps, and wind turbines. Their working principle involves a hydraulic cylinder-like device fitted onto the bolt and nut. An internally threaded tension ring is screwed onto the bolt's threaded end, while the hydraulic cylinder applies tension force to the tension ring under oil pressure, thus tightening the nut. However, in this high-pressure, dynamic working environment, improper operation can easily lead to excessive pressure and overstretching of the bolt, posing potential dangers to equipment and operators. Utility Model Content

[0003] In order to solve the above-mentioned technical problems, one of the objectives of this utility model is to provide an automatic pressure relief and limiting hydraulic telescopic component with a telescopic stroke that can be limited.

[0004] To achieve the above objectives, the technical solution of this utility model is as follows: An automatic pressure relief and limiting hydraulic telescopic component includes a cylinder ring, a piston ring, and a pressure relief component. Both the cylinder ring and piston ring are vertically arranged. The piston ring is coaxially placed inside the cylinder ring, with an annular gap between them. The lower end of the cylinder ring has an inner flange that seals with the piston ring, and the upper end of the piston ring has an outer flange that seals with the cylinder ring, thus enclosing the annular gap to form an annular cavity. The outer wall of the cylinder ring has a hydraulic port communicating with the bottom of the annular cavity. The pressure relief component is disposed on the outer wall of the cylinder ring, and a pressure relief flow channel communicating with the pressure relief component is also provided on the side wall of the cylinder ring. When the piston ring moves upward relative to the cylinder ring until the annular cavity communicates with the pressure relief flow channel, pressure is released to limit the upward sliding stroke of the piston ring.

[0005] The beneficial effect of the above technical solution is that the piston ring moves upward under the lifting action of hydraulic pressure until the annular cavity is connected to the pressure relief channel. At this moment, the hydraulic oil that is continuously injected will be discharged to the pressure relief component through the pressure relief channel. At this time, the piston ring will not continue to move upward relative to the cylinder liner ring.

[0006] In the above technical solution, both the inner side of the inner flange and the outer side of the outer flange are coaxially fitted with sealing rings.

[0007] The beneficial effect of the above technical solution is that it makes the sealing performance of the annular cavity formed by the cylinder liner ring and piston ring well.

[0008] In the above technical solution, a marking ring is also coaxially provided on the outer side of the outward flange.

[0009] The beneficial effect of the above technical solution is that it allows the operator to determine the piston ring to be in place the instant the marking ring is exposed outside the cylinder liner ring.

[0010] The pressure relief component described in the above technical solution includes a grooved cover, which is connected to the outer wall of the cylinder liner ring, and the pressure relief channel is connected to the inside of the grooved cover. The grooved cover has a pressure relief port.

[0011] The beneficial effect of the above technical solution is that it can prevent the hydraulic oil flowing out through the pressure relief channel from spraying outward, while the grooved cover plays a role in buffering and blocking.

[0012] In the above technical solution, the pressure relief channel is flared at the end near the grooved cover.

[0013] The beneficial effect of the above technical solution is that the hydraulic oil is ejected from the pressure relief channel in a divergent manner, which avoids generating a large impact force on the grooved cover.

[0014] The pressure relief component described in the above technical solution also includes a valve core and an elastic element. Both the valve core and the elastic element are placed inside the grooved cover. The elastic element is located between the valve core and the inner bottom wall of the grooved cover. The elastic force of the elastic element is used to drive the valve core to move closer to the pressure relief channel.

[0015] The beneficial effect of the above technical solution is that the valve core and the elastic element can work together to buffer the hydraulic oil ejected from the pressure relief channel, thereby reducing the impact force on the grooved cover.

[0016] In the above technical solution, the valve core is a ball, the elastic element is a spring, a limiting ring is protruding on the inner wall of the grooved cover, and the pressure relief port is located on the side of the limiting ring close to the pressure relief flow channel. The limiting ring is used to limit the retraction stroke of the valve core.

[0017] The advantages of the above technical solution are: its structure is simple, and the limiting ring can limit the return stroke of the valve core to avoid excessive compression of the elastic element.

[0018] The valve core described in the above technical solution includes a flow divider plate, a flow divider tube, and multiple connecting rods. The flow divider tube is slidably and sealingly disposed within the grooved cover. The flow divider plate is disposed within the grooved cover and located at the end of the flow divider tube away from the pressure relief channel. The flow divider plate is concave, and the groove of the flow divider plate faces the flow divider tube. There is a gap between the flow divider plate and the flow divider tube, and multiple connecting rods are arranged circumferentially between them. The two ends of each connecting rod are connected to the flow divider tube and the flow divider plate, respectively. A flow divider hole is formed between two adjacent connecting rods, and the pressure relief port is aligned with at least one of the flow divider holes.

[0019] The beneficial effects of the above technical solution are: its structure is simple, which allows the hydraulic oil sprayed through the pressure relief channel to be blocked by the flow divider plate and splashed out through the flow divider hole to the outside of the flow divider guide cylinder, and discharged through the pressure relief port.

[0020] The elastic element described in the above technical solution is a C-shaped spring sheet.

[0021] The advantages of the above technical solution are that it has a simple structure and good durability.

[0022] The second objective of this utility model is to provide a bolt hydraulic tensioner with a simple structure and good safety.

[0023] To achieve the above objectives, the technical solution of this utility model is as follows: A bolt hydraulic tensioner includes a support cylinder, a tension ring, and an automatic pressure relief and limiting hydraulic telescopic component as described above. The support cylinder is coaxially disposed at the lower end of the cylinder sleeve ring, and an operating hole is provided on the side wall of the support cylinder. The inner hole of the tension ring is a threaded hole, and the tension ring is used to support the piston ring. The inner diameter of the tension ring is smaller than the inner diameter of the piston ring.

[0024] The beneficial effect of the above technical solution is that the extension stroke of the automatic pressure relief and limiting hydraulic telescopic component used in the bolt hydraulic tensioner is limited, thus ensuring its safety. Attached Figure Description

[0025] Figure 1 This is a cross-sectional view of the automatic pressure relief and limiting hydraulic telescopic component described in Embodiment 1 of this utility model;

[0026] Figure 2 This is a cross-sectional view of the automatic pressure relief and limiting hydraulic telescopic component described in Embodiment 2 of this utility model;

[0027] Figure 3 This is a schematic diagram of the pressure relief channel configuration described in Embodiment 2 of this utility model;

[0028] Figure 4 This is a cross-sectional view of the pressure relief component described in Embodiment 3 of this utility model;

[0029] Figure 5 This is a cross-sectional view of the pressure relief component described in Embodiment 4 of this utility model;

[0030] Figure 6 This is an elevation view of the valve core described in Embodiment 4 of this utility model;

[0031] Figure 7 This is a cross-sectional view of the bolt hydraulic tensioner described in Embodiment 5 of this utility model;

[0032] Figure 8 This is a cross-sectional view of the tension ring, the automatic pressure relief and limiting hydraulic telescopic component, and the support cylinder as described in Embodiment 5 of this utility model when they are separated.

[0033] Figure 9 This is a schematic diagram of the bolt hydraulic tensioner described in Embodiment 5 of this utility model being assembled with a bolt.

[0034] In the diagram: 1. Automatic pressure relief and limiting hydraulic telescopic component; 11. Cylinder liner ring; 111. Inner flange; 112. Insert ring; 12. Piston ring; 121. Outer flange; 13. Pressure relief component; 131. Groove cover; 1311. Pressure relief port; 1312. Limiting ring; 132. Valve core; 1321. Diverter plate; 1322. Diverter guide tube; 1323. Connecting rod; 1324. Diverter hole; 133. Elastic component; 14. Annular cavity; 15. Hydraulic port; 16. Pressure relief flow channel; 17. Sealing ring; 18. Marking ring; 2. Support cylinder; 21. Operating hole; 3. Tension ring; 31. Ring support; 4. Bolt; 5. Nut. Detailed Implementation

[0035] The principles and features of this utility model are described below with reference to the accompanying drawings. The examples given are for illustrative purposes only and are not intended to limit the scope of this utility model. The utility model is described more specifically in the following paragraphs by way of example with reference to the accompanying drawings. The advantages and features of this utility model will become clearer from the following description and claims. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of this utility model.

[0036] Example 1

[0037] like Figure 1As shown, this embodiment provides an automatic pressure relief and limiting hydraulic telescopic component, including a cylinder sleeve ring 11, a piston ring 12, and a pressure relief component 13. Both the cylinder sleeve ring 11 and the piston ring 12 are vertically arranged. The piston ring 12 is coaxially placed inside the cylinder sleeve ring 11, with an annular gap between them. The lower end of the cylinder sleeve ring 11 has an inner flange 111 that seals against the piston ring 12, and the upper end of the piston ring 12 has an outer flange 121 that seals against the cylinder sleeve ring 11, thus enclosing the annular gap to form an annular cavity 14. The outer wall of the cylinder sleeve ring 11 has a hydraulic line communicating with the bottom end of the annular cavity 14. Port 15, the pressure relief component 13 is disposed on the outer wall of the cylinder sleeve ring 11, and the side wall of the cylinder sleeve ring 11 is also provided with a pressure relief flow channel 16 communicating with the pressure relief component 13. When the piston ring 12 moves upward relative to the cylinder sleeve ring 11 to the point where the annular cavity 14 communicates with the pressure relief flow channel 16, pressure is relieved to limit the upward sliding stroke of the piston ring 12. Thus, when the piston ring moves upward under the lifting action of hydraulic pressure to the moment when the annular cavity communicates with the pressure relief flow channel, the hydraulic oil that is continuously injected at this time will be discharged to the pressure relief component through the pressure relief flow channel. At this time, the piston ring will not continue to move upward relative to the cylinder sleeve ring.

[0038] like Figure 1 As shown, in the above technical solution, the inner side of the inner flange 111 and the outer side of the outer flange 121 are coaxially fitted with sealing rings 17 (in this embodiment, the installation location of the sealing ring is coaxially recessed with a sealing groove, so that the sealing ring can be embedded in the sealing groove, which is the prior art of sealing ring installation, and will not be described in detail here), thus making the sealing performance of the annular cavity formed by the cylinder liner ring and the piston ring good.

[0039] like Figure 1 As shown, a marking ring 18 is coaxially provided on the outer side of the outer flange 121 in the above technical solution, so that the operator can judge that the piston ring has been lifted to the correct position by observing the moment the marking ring is exposed outside the cylinder liner ring. In this embodiment, the marking ring can be an annular groove, or a ring of a conspicuous color such as black, red, yellow, or blue can be provided in the annular groove. Specifically, when the automatic pressure relief and limiting hydraulic telescopic component provided in this embodiment extends, if the marking ring is exposed, it indicates that the automatic pressure relief and limiting hydraulic telescopic component has been extended to the correct position, and the supply of hydraulic oil should be stopped. However, if the operator fails to notice the marking ring due to negligence, the automatic pressure relief and limiting hydraulic telescopic component will continue to extend until it connects with the pressure relief component to release oil.

[0040] like Figure 1As shown, the pressure relief component 13 in the above technical solution includes a grooved cover 131, which is mated to the outer wall of the cylinder liner ring 11. The pressure relief channel 16 communicates with the inside of the grooved cover 131. The grooved cover 131 has a pressure relief port 1311, which prevents hydraulic oil exiting the pressure relief channel from spraying outwards, while the grooved cover acts as a buffer and shield. In this embodiment, the grooved cover can be installed on the cylinder liner ring by bolts, or it can be directly installed on the cylinder liner ring by welding.

[0041] In this embodiment, multiple pressure relief ports can be arranged circumferentially at intervals on the side wall of the groove-shaped cover.

[0042] The pressure relief component described in this embodiment can also prevent dust from entering the annular cavity.

[0043] In this embodiment, the diameter of the pressure relief channel opening is positively correlated with the size of the bottom wall of the annular cavity.

[0044] Example 2

[0045] like Figure 2 As shown, the difference is that the pressure relief channel 16 is flared at one end near the grooved cover 131 (the flare can be trumpet-shaped, and the inner wall of the flare can be a V-shaped conical wall or a C-shaped arc wall), so that the hydraulic oil is ejected from the pressure relief channel in a divergent manner, which can avoid generating a large impact force on the grooved cover.

[0046] Of course, such as Figure 3 As shown, in this embodiment, the pressure relief channel can also extend into the grooved cover in an arc shape, with the opening of its extension gradually increasing and the end bending to align with the outer wall of the cylinder liner ring, so that the hydraulic oil injected from the pressure relief channel is directed to the cylinder liner ring for buffering.

[0047] Example 3

[0048] like Figure 4As shown, similar to Embodiment 1 or Embodiment 2, the difference is that the pressure relief component 13 further includes a valve core 132 and an elastic element 133. The valve core 132 and the elastic element 133 are both placed inside the grooved cover 131. The elastic element 133 is located between the valve core 132 and the inner bottom wall of the grooved cover 131. The elastic force of the elastic element 133 is used to drive the valve core 132 to move closer to the pressure relief channel 16. This allows the valve core and the elastic element to work together to buffer the hydraulic oil ejected from the pressure relief channel, thereby reducing the impact force on the grooved cover. Preferably, the valve core 132 is a sphere (it can also be cylindrical, conical, or frustum-shaped), the elastic element 133 is a spring, and a limiting ring 1312 is protruding on the inner wall of the grooved cover 131. The pressure relief port 1311 is located on the side of the limiting ring 1312 near the pressure relief channel 16. The limiting ring 1312 is used to limit the retraction stroke of the valve core 132. Its structure is simple, and the limiting ring can limit the retraction stroke of the valve core to avoid the elastic element being over-compressed (in this embodiment, the valve core 132 can move to block the pressure relief channel under the action of the elastic force of the elastic element, and when there is hydraulic oil ejected in the pressure relief channel, the valve core can retract to open the pressure relief channel under the action of the jet impact).

[0049] In this embodiment, the valve core and elastic element work together to buffer the hydraulic oil jet discharged from the pressure relief channel, thereby reducing its impact on the grooved cover.

[0050] Preferably, the end of the pressure relief channel near the pressure relief component is flared, and it is combined with the valve core and elastic element. This can further reduce the impact force of the hydraulic oil jet on the pressure relief component, thereby improving the durability of the pressure relief component.

[0051] Example 4

[0052] like Figure 5 and Figure 6As shown, similar to Embodiment 3, the difference lies in that the valve core 132 includes a flow divider plate 1321, a flow divider guide cylinder 1322, and multiple connecting rods 1323. The flow divider guide cylinder is slidably disposed within the grooved cover. The flow divider plate is disposed within the grooved cover and located at the end of the flow divider guide cylinder away from the pressure relief channel 16. The flow divider plate 1321 is concave, and the slot of the flow divider plate 1321 faces the flow divider guide cylinder 1322. The flow divider plate 1321 and the flow divider guide cylinder 1322 are connected... The valve core has gaps and multiple connecting rods 1323 arranged circumferentially between it and the flow divider 1322. Each connecting rod 1323 is connected at both ends to the flow divider cylinder 1322 and the flow divider plate 1321, respectively. A flow divider hole 1324 is formed between two adjacent connecting rods 1323. The pressure relief port 1311 is aligned with at least one of the flow divider holes 1324. This simple structure allows the hydraulic oil ejected through the pressure relief channel to be blocked by the flow divider plate and splashed out through the flow divider hole to the outside of the flow divider cylinder, and then discharged through the pressure relief port. Preferably, at least three connecting rods are provided. When the valve core is in the reset state, the flow divider cylinder abuts against the outer wall of the cylinder liner ring.

[0053] The elastic element 133 described in the above technical solution is a C-shaped spring sheet, which has a simple structure and good durability.

[0054] In this embodiment, the C-shaped spring has a small deformation, and its main purpose is to provide a buffering elastic force for the valve core. The width of the gap between the diverter plate 1321 and the diverter guide cylinder 1322 is greater than the deformation of the elastic element, so that the diverter hole 1324 can remain in communication with the pressure relief port 1311 when the valve core retracts.

[0055] Example 5

[0056] like Figure 7 and Figure 8 As shown, this embodiment provides a bolt hydraulic tensioner, including a support cylinder 2, a tension ring 3, and an automatic pressure relief and limiting hydraulic telescopic component 1 as described in Embodiments 1, 2, 3, or 4. The support cylinder 2 is coaxially disposed at the lower end of the cylinder liner ring 11, and an operating hole 21 is provided on the side wall of the support cylinder 2. The inner hole of the tension ring 3 is a threaded hole, and the tension ring 3 is used to support the piston ring 12. The inner diameter of the tension ring 3 is smaller than the inner diameter of the piston ring 12. The extension stroke of the automatic pressure relief and limiting hydraulic telescopic component used in this bolt hydraulic tensioner is limited, so its safety is good.

[0057] like Figure 7 and Figure 8As shown, in this embodiment, the operating hole is used to allow a wrench to be inserted into the support cylinder to tighten the nut (in this embodiment, the operating hole can also be a notch that penetrates the lower end of the support cylinder, allowing the head of the wrench to be inserted and providing a certain amount of room for the wrench to rotate; preferably, the arc angle corresponding to the operating hole should not be greater than 180°, otherwise it may affect the stability of the support). In this embodiment, the inner hole of the tension ring is used to be threadedly connected to the threaded end of the bolt to tighten the bolt. In this embodiment, the inner diameter of the support cylinder and the inner diameter of the piston ring are both larger than the outer diameter of the nut and the bolt head.

[0058] like Figure 7 and Figure 8 As shown, in this embodiment, the outer diameter of the tension ring 3 can also be smaller than the inner diameter of the piston ring, but the upper end of the tension ring can be turned outward to form a ring support 31, and the outer diameter of the ring support is larger than the inner diameter of the piston ring (at this time, the tension ring is supported on the piston ring by the ring support, and the lower end of the tension ring extends into the piston ring, which makes its support on the piston ring more reliable). In this way, after the nut is tightened on the bolt, the tension ring can be unscrewed from the bolt, and the entire support cylinder and the automatic pressure relief and limit hydraulic telescopic component can be easily removed from the bolt.

[0059] like Figure 8 As shown, preferably, the support cylinder can be detachably assembled at the lower end of the cylinder sleeve ring by plugging. At this time, the lower end of the inner flange can be coaxially provided with a plug-in ring 112, and the inner diameter of the plug-in ring 112 is equivalent to the outer diameter of the support cylinder. At this time, the upper end of the support cylinder can be inserted into the plug-in ring for assembly. After use, the support cylinder can be separated from the automatic pressure relief and limit hydraulic telescopic component.

[0060] like Figure 9 As shown, when using the bolt hydraulic tensioner, first pre-tighten the nut 5 on the bolt 4, then put the support cylinder and the automatic pressure relief and limit hydraulic telescopic component on the outside of the bolt and assemble them, then install the tension ring on the bolt 4, and screw the tension ring onto the piston ring. At this time, supply hydraulic pressure to the automatic pressure relief and limit hydraulic telescopic component, insert the wrench through the operating hole until it engages with the nut, and gradually tighten the nut.

[0061] The automatic pressure relief and limiting hydraulic telescopic component provided in this embodiment has a self-limiting function, which can prevent the piston ring from moving upward and becoming loose from the cylinder liner ring, and at the same time prevent the bolt from being overstretched and causing mechanical damage.

[0062] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model in any way. Those skilled in the art can readily implement this utility model based on the accompanying drawings and the above description. However, any modifications, alterations, or equivalent variations made by those skilled in the art without departing from the scope of the utility model's technical solution, utilizing the disclosed technical content, are considered equivalent embodiments of this utility model. Furthermore, any equivalent changes, alterations, or variations made to the above embodiments based on the essential technology of this utility model are still within the protection scope of this utility model's technical solution.

Claims

1. An automatic pressure relief limiting hydraulic telescopic member, characterized by, The device includes a cylinder liner ring (11), a piston ring (12), and a pressure relief component (13). Both the cylinder liner ring (11) and the piston ring (12) are vertically oriented. The piston ring (12) is coaxially positioned within the cylinder liner ring (11), with an annular gap between them. The lower end of the cylinder liner ring (11) has an inner flange (111) that seals against the piston ring (12), and the upper end of the piston ring (12) has an outer flange (121) that seals against the cylinder liner ring (11), thus enclosing the annular gap to form an annular cavity (14). The cylinder ring (11) has a hydraulic port (15) on its outer wall that communicates with the bottom end of the annular cavity (14). The pressure relief component (13) is provided on the outer wall of the cylinder ring (11), and the side wall of the cylinder ring (11) is also provided with a pressure relief channel (16) that communicates with the pressure relief component (13). When the piston ring (12) moves upward relative to the cylinder ring (11) to the point where the annular cavity (14) communicates with the pressure relief channel (16), pressure is relieved to limit the upward sliding stroke of the piston ring (12).

2. The self-relieving pressure limiting hydraulic telescopic member according to claim 1, wherein, The inner side of the inner flange (111) and the outer side of the outer flange (121) are both coaxially fitted with sealing rings (17).

3. The self-relieving pressure limiting hydraulic telescopic member according to claim 1, wherein, A marking ring (18) is also coaxially provided on the outer side of the outward flange (121).

4. The self-relieving pressure limiting hydraulic telescopic member according to claim 1, wherein, The pressure relief component (13) includes a grooved cover (131), which is mated to the outer wall of the cylinder liner ring (11), and the pressure relief channel (16) communicates with the inside of the grooved cover (131). The grooved cover (131) has a pressure relief port (1311).

5. The self-relieving pressure limiting hydraulic telescopic member according to claim 4, wherein, The pressure relief channel (16) is flared at one end near the grooved cover (131).

6. The self-relieving pressure limiting hydraulic telescopic piece according to claim 4 or 5, characterized in that, The pressure relief component (13) also includes a valve core (132) and an elastic element (133), both of which are placed inside the grooved cover (131). The elastic element (133) is located between the valve core (132) and the inner bottom wall of the grooved cover (131). The elastic force of the elastic element (133) is used to drive the valve core (132) to move closer to the pressure relief channel (16).

7. The automatic pressure relief and limiting hydraulic telescopic component according to claim 6, characterized in that, The valve core (132) is a sphere, the elastic element (133) is a spring, a limiting ring (1312) is protruding on the inner wall of the grooved cover (131), and the pressure relief port (1311) is located on the side of the limiting ring (1312) close to the pressure relief channel (16). The limiting ring (1312) is used to limit the retraction stroke of the valve core (132).

8. The self-relieving pressure limiting hydraulic telescopic member according to claim 6, wherein, The valve core (132) includes a flow divider plate (1321), a flow divider guide cylinder (1322), and multiple connecting rods (1323). The flow divider guide cylinder is slidably disposed within the grooved cover. The flow divider plate is disposed within the grooved cover and located at the end of the flow divider guide cylinder away from the pressure relief channel (16). The flow divider plate (1321) is concave, and the groove of the flow divider plate (1321) faces the flow divider guide cylinder (1322). There is a gap between (1321) and the diversion guide tube (1322), and multiple connecting rods (1323) are arranged circumferentially between them. The two ends of each connecting rod (1323) are connected to the diversion guide tube (1322) and the diversion plate (1321) respectively. A diversion hole (1324) is formed between two adjacent connecting rods (1323), and the pressure relief port (1311) is aligned with at least one of the diversion holes (1324).

9. The self-relieving pressure limiting hydraulic telescopic member according to claim 8, wherein, The elastic element (133) is a C-shaped spring sheet.

10. A hydraulic tensioner for a bolt, characterized by The device includes a support cylinder (2), a tension ring (3), and an automatic pressure relief and limiting hydraulic telescopic component (1) as described in any one of claims 1-9. The support cylinder (2) is coaxially disposed at the lower end of the cylinder liner ring (11), and an operating hole (21) is provided on the side wall of the support cylinder (2). The inner hole of the tension ring (3) is a threaded hole, and the tension ring (3) is used to support the piston ring (12). The inner diameter of the tension ring (3) is smaller than the inner diameter of the piston ring (12).

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