A medium speed marine diesel engine connecting rod bolt assembly elongation measuring instrument

Abstract

The application relates to a connecting rod bolt assembly elongation measuring instrument for a medium-speed marine diesel engine. The measuring instrument comprises a pipeline, a telescopic rod arranged on the pipeline, an injection pipe arranged in the pipeline, a channel arranged between the telescopic rod and the injection pipe and communicating with an inner cavity of the telescopic rod and an inner cavity of the injection pipe, a scale arranged on the injection pipe, a piston arranged in the injection pipe, hydraulic oil arranged in the inner cavity of the injection pipe, the channel and the inner cavity of the telescopic rod, a pulley arranged on the pipeline, a reset spring arranged on the pipeline, and the like. The application solves the problem that the bolt cannot be measured during the counterbore assembly by arranging a blind hole on the side of the bolt hole and then measuring the bolt elongation by using the measuring instrument, and the bolt with a relatively large length can also be measured. The structure is simple, the equipment is small and easy to operate and carry.

Description

Technical Field

[0001] This invention belongs to the field of measurement technology, specifically relating to a measuring instrument for measuring the elongation of connecting rod bolts in a medium-speed marine diesel engine. Background Technology

[0002] Connecting rod is one of the main transmission components of a diesel engine, and its importance within the engine is self-evident. It is the primary moving part that transmits power, performing complex planar motion within the engine block. The small end of the connecting rod reciprocates up and down with the piston; the large end rotates at high speed with the crankshaft; and the connecting rod body oscillates complexly under the combined motion of the large and small end bores. In addition to bearing reciprocating inertial forces, the connecting rod must also withstand the pressure of high-pressure gas. The combination of gas pressure and inertial forces creates alternating loads, requiring the connecting rod to possess fatigue resistance, impact resistance, sufficient strength, rigidity, and good toughness. Therefore, in actual engine operation, controlling the elongation of the connecting rod bolts during tightening is particularly important.

[0003] As the precision of preload for large bolts increases, bolt elongation is commonly used as the standard for preload tightening. Existing methods for measuring bolt elongation include: using dial indicators on the upper and lower ends of the bolt. This technique involves measuring the axial dimensional changes of the bolt using dial indicators during tightening to calculate the bolt elongation.

[0004] Several technical solutions for measuring bolt assembly elongation have emerged in the prior art. For example, a Chinese patent with application number CN201810445438.9 discloses a connecting rod bolt elongation measuring device and method. This method uses a coarse locating pin, a fixed detection pin, and a movable detection pin to fix the connecting rod. A dial indicator measures the length of the connecting rod bolt before and after tightening, and then calculates the elongation of the connecting rod bolt. The measurement accuracy is high. This solves the problem that ultrasonic testing requires high precision on both ends of the bolt, and high-horsepower connecting rod bolts have pre-machined ejector pin holes on both ends, resulting in uneven end faces and inaccurate data detection.

[0005] The technology has the following drawbacks: some large bolts use countersunk hole connections, making it impossible to measure the change in the size of the lower end face of the bolt. Therefore, it cannot be applied to all bolts. Furthermore, when the bolts are long, the device becomes large and inconvenient to carry and use. Summary of the Invention

[0006] The purpose of this invention is to provide a measuring instrument for the elongation of connecting rod bolts in medium-speed marine diesel engines, in order to solve the problems mentioned in the background art.

[0007] The present invention achieves the above objectives through the following technical solutions:

[0008] An elongation measuring instrument for connecting rod bolts of a medium-speed marine diesel engine includes: a pipe;

[0009] Expansion rods installed on pipelines;

[0010] An injection tube is installed inside the pipeline. A channel connecting the inner cavity of the telescopic rod and the inner cavity of the injection tube is provided between the injection tube and the telescopic rod. The injection tube is marked with graduations.

[0011] A piston located inside the injection tube;

[0012] Hydraulic oil located in the inner cavity of the injection tube, the channel, and the inner cavity of the telescopic rod;

[0013] Pulleys installed on pipes;

[0014] A return spring installed on the pipe;

[0015] And a connecting rope is installed on the pulley, one end of which is connected to the telescopic rod, and the other end of which passes through the pulley and then through the pipe;

[0016] Drill a blind hole in the connecting rod down to the bottom of the bolt hole, connecting the blind hole to the bolt hole. Install the bolt into the bolt hole, ensuring the bolt cap is in contact with the connecting rod. Insert the pipe into the blind hole and pull the connecting rope to rotate the telescopic rod. The telescopic rod rotates until it contacts the pulley and then stops. Move the piston to inject hydraulic oil from the injection tube into the inner cavity of the telescopic rod, causing it to extend and press against the bolt. Tighten the bolt; the extended bolt compresses the telescopic rod, allowing the hydraulic oil in the telescopic rod to enter the injection tube. Observe the change in the hydraulic oil level in the injection tube according to the scale value to obtain the bolt elongation.

[0017] Preferably, the telescopic rod includes a first section, a second section, and a third section with successively decreasing diameters;

[0018] The inner wall of the first section is provided with a groove and a stop block. A spring is provided in the groove, a locking block is provided on the spring, and an inclined surface is provided on the locking block.

[0019] The second section has slots No. 2, No. 3 and No. 4. There is a passage between slots No. 2 and No. 3, which is filled with hydraulic oil. Slot No. 4 has a No. 2 locking block. Slot No. 5 and No. 1 through hole are located deep in slot No. 4. Slot No. 2 is located in slot No. 5.

[0020] The third section has a No. 6 slot and a No. 3 locking block. The No. 6 slot, the No. 1 through hole and the No. 5 slot are on the same straight line. The No. 4 locking block with a notch is located at the No. 6 slot.

[0021] When the telescopic rod extends, the hydraulic oil drives the third section to extend, and after the third section extends, the second section extends again.

[0022] When the telescopic pole is shortened, the second section shortens first, and then the third section shortens after the second section has shortened.

[0023] Preferably, the injection tube includes a first tube and a second tube, wherein the diameter of the second tube is greater than the diameter of the first tube.

[0024] Preferably, the first tube is provided with a fifth locking block, the fifth locking block is provided with a groove and a second through hole, the piston enters the fifth locking block at the groove, and the piston is provided with an insertion rod that passes through the second through hole.

[0025] Preferably, a first magnetic block is provided at the joint of the first and second pipes, and the fifth card block is made of a magnetic material with the opposite magnetic properties to the first magnetic block.

[0026] The beneficial effects of this invention are as follows:

[0027] This invention solves the problem of bolts being unmeasurable during countersunk hole assembly by creating blind holes on the side of the bolt holes and then using a measuring instrument to measure the bolt elongation. It can also measure longer bolts. The structure is simple, and the equipment is compact, easy to operate and carry. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0029] Figure 2 yes Figure 1 Enlarged view of point A in the middle;

[0030] Figure 3 This is a cross-sectional view of the telescopic rod in this invention;

[0031] Figure 4 yes Figure 3 Enlarged view of point B in the middle;

[0032] Figure 5 This is a schematic diagram showing the positional relationship between card block No. 2 and card block No. 4 in this invention;

[0033] Figure 6 This is a schematic diagram illustrating the working principle of the present invention.

[0034] In the diagram: 1. Pipe; 2. Telescopic rod; 3. Injection tube; 4. Piston; 5. Pulley; 6. Return spring; 7. Connecting rope; 8. First section; 9. Second section; 10. Third section; 11. Slot 1; 12. Stop block 1; 13. Spring 1; 14. Locking block 1; 15. Slot 2; 16. Slot 3; 17. Slot 4; 18. Locking block 2; 19. Slot 5; 20. Through hole 1; 21. Spring 2; 22. Slot 6; 23. Locking block 3; 24. Notch; 25. Locking block 4; 26. Pipe 1; 27. Pipe 2; 28. Locking block 5; 29. ​​Groove; 30. Through hole 2; 31. Magnetic block 1; 32. Blind hole; 33. Bolt hole. Detailed Implementation

[0035] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0036] Example 1

[0037] like Figure 1-6 As shown, a medium-speed marine diesel engine connecting rod bolt assembly elongation measuring instrument includes: pipe 1;

[0038] Expansion rod 2 installed on pipe 1;

[0039] An injection tube 3 is installed inside the pipe 1. A channel is provided between the injection tube 3 and the telescopic rod 2 to connect the inner cavity of the telescopic rod 2 and the inner cavity of the injection tube 3. The injection tube 3 is marked with graduations.

[0040] Piston 4 is located inside injection tube 3;

[0041] Hydraulic oil is located in the inner cavity of the injection tube 3, the channel, and the inner cavity of the telescopic rod 2;

[0042] Pulley 5 is installed on pipe 1;

[0043] A return spring 6 is installed on pipe 1;

[0044] And a connecting rope 7 is provided on the pulley 5. One end of the connecting rope 7 is connected to the telescopic rod 2, and the other end of the connecting rope 7 passes through the pulley 5 and then through the pipe 1.

[0045] A blind hole 32 is drilled on the connecting rod to the bottom of the bolt hole 33, connecting the blind hole 32 and the bolt hole 33. The bolt is then installed into the bolt hole 33, with the bolt cap in contact with the connecting rod. The pipe 1 is inserted into the blind hole 32. The connecting rope 7 is pulled, causing the telescopic rod 2 to rotate. The telescopic rod 2 rotates until it contacts the pulley 5 and then stops rotating. The piston 4 is moved to inject hydraulic oil from the injection tube 3 into the inner cavity of the telescopic rod 2, causing the telescopic rod 2 to extend and press against the bolt. The bolt is then tightened. The extended bolt compresses the telescopic rod 2, allowing the hydraulic oil in the telescopic rod 2 to enter the injection tube 3. The change in the hydraulic oil level in the injection tube 3 is observed to obtain the bolt elongation. After the measurement is completed, the piston 4 is pulled, causing the hydraulic oil in the telescopic rod 2 to be extracted, thus shortening the telescopic rod 2. The connecting rope 7 is released, and the telescopic rod 2 rotates under the action of the return spring 6, pulling the pipe 1 out from the drilled blind hole 32.

[0046] As a further embodiment of the present invention, the telescopic rod 2 includes a first segment 8, a second segment 9, and a third segment 10 with successively decreasing diameters;

[0047] The inner wall of the first section 8 is provided with a groove 11 and a stop block 12. A spring 13 is provided in the groove 11. A locking block 14 is provided on the spring 13. An inclined surface is provided on the locking block 14.

[0048] The second section 9 is provided with slot 2 15, slot 3 16 and slot 4 17. There is a passage between slot 2 15 and slot 3 16, which is filled with hydraulic oil. Slot 4 17 is provided with a second locking block 18 with a slope. Slot 5 19 and a first through hole 20 are provided at the depth of slot 4 17. A second spring 21 is provided at slot 5 19.

[0049] The third section 10 is provided with a sixth slot 22 and a third locking block 23. The sixth slot 22 is on the same straight line as the first through hole 20 and the fifth slot 19. The sixth slot 22 is provided with a fourth locking block 25 with a notch 24.

[0050] When telescopic rod 2 extends, hydraulic oil drives the third section 10 to extend, and after the third section 10 extends, the second section 9 extends again.

[0051] When telescopic rod 2 is shortened, the second segment 9 is shortened first, and then the third segment 10 is shortened after the second segment 9 is shortened.

[0052] In the above embodiment, because each segment of the telescopic rod 2 has a different diameter, if each segment shortens and lengthens during the extension and shortening process, the liquid level at the injection tube 3 will be inaccurate, making it unclear which segment is moving, thus resulting in inaccurate measurements. The telescopic rod 2 is improved so that when it extends, hydraulic oil is injected into it. Because the first locking block 14 of the first segment 8 is located at the second groove 15 of the second segment 9, the second segment 9 cannot move, while the third segment 10 can move freely. The extension process stops when the third segment 10 contacts the bolt. If the third segment 10 is fully extended but has not yet contacted the bolt, hydraulic oil injection continues. When the third segment 10 reaches its maximum stroke, the third locking block 23 enters the third groove 16 of the second segment 9, causing the hydraulic oil in the third groove 16 to be forced towards the second groove 15, thus squeezing out the first locking block 14 at the second groove 15, and allowing the second segment 9 to be in a free state. That is, the second segment 9 begins to extend after the third segment 10 is fully extended. During the extension of the second segment 9, if it still cannot make contact with the bolt, a new blind hole 32 is drilled. When the third segment 10 is fully extended, the first through hole 20, the sixth slot 22, and the fifth slot 19 are aligned on the same straight line. The second spring 21 at the fifth slot 19 causes the fourth locking block 25 to enter the sixth slot 22, thus preventing the third segment 10 from moving relative to the second segment 9.

[0053] When telescopic rod 2 shortens, the second segment 9 shortens first because the third segment 10 is held in place by the fourth locking block 25. After the second segment 9 is fully shortened, the first stop block 12 enters the fourth slot 17, causing the second locking block 18 to move. When the inclined surface of the second locking block 18 contacts the fourth locking block 25, it moves away from the third segment 10 through the notch 24 of the fourth locking block 25, thus freeing the third segment 10. Simultaneously, as the second segment 9 reaches its fully shortened state, the inclined surface of the first stop block 12 causes the first stop block 12 to first enter the first slot 11 and then pop out into the second slot 15, thus limiting the movement of the second segment 9.

[0054] The hydraulic oil in the passage will not enter the hydraulic oil circulation inside the telescopic rod 2, and will not affect the measurement of the amount of hydraulic oil.

[0055] After the improvement, each elongation occurs with the third segment 10 elongating first, followed by the second segment 9; and each shortening occurs with the second segment 9 shortening first, followed by the third segment 10. This makes the movement of the liquid level at injection tube 3 regular, and the movement of each segment is sequential, preventing simultaneous shortening and elongation.

[0056] As a further embodiment of the present invention, the injection tube 3 includes a first tube 26 and a second tube 27, wherein the diameter of the second tube 27 is greater than the diameter of the first tube 26.

[0057] As a further embodiment of the present invention, the first tube 26 is provided with a fifth locking block 28, the fifth locking block 28 is provided with a groove 29 and a second through hole 30, the piston 4 enters the fifth locking block 28 at the groove 29, and the piston 4 is provided with an insertion rod that passes through the second through hole 30.

[0058] As a further embodiment of the present invention, a first magnetic block 31 is provided at the joint of the first tube 26 and the second tube 27, and the fifth card block 28 is made of a magnetic material with the opposite magnetic properties to the first magnetic block 31.

[0059] In the above embodiment, the arrangement of tube 26 and tube 27 makes the liquid level change at injection tube 3 more uniform, thereby making the scale on injection tube 3 more uniform and able to change according to the different positions of the telescopic rod 2, thus making the scale reading easier. At the same time, piston 4 can freely enter and exit the fifth locking block 28. When the fifth locking block 28 moves to the joint of tube 26 and tube 27, it can no longer move, but piston 4 can still enter tube 26 to inject hydraulic oil into the telescopic rod 2.

[0060] Among them, the fifth locking block 28 and the first magnetic block 31 have a magnetic attraction, which allows the fifth locking block 28 to not move freely in the second pipe 27 when it is detached from the piston 4. That is, the fifth locking block 28 will not move during the process of the piston 4 injecting oil into the telescopic rod 2, so that the fifth locking block 28 can stick tightly to the first pipe 26, preventing hydraulic oil from leaking into the first pipe 26 when the piston 4 enters the groove 29, thereby reducing the amount of hydraulic oil and reducing the measurement error.

[0061] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A measuring instrument for measuring the elongation of connecting rod bolts in a medium-speed marine diesel engine, characterized in that, include: Pipeline (1); Telescopic rod (2) installed on pipe (1); An injection tube (3) is installed inside the pipe (1). A channel is provided between the injection tube (3) and the telescopic rod (2) to connect the inner cavity of the telescopic rod (2) and the inner cavity of the injection tube (3). The injection tube (3) is marked with graduations. A piston (4) is located inside the injection tube (3); Hydraulic oil is placed in the inner cavity of the injection tube (3), the channel, and the inner cavity of the telescopic rod (2); A pulley (5) is installed on the pipe (1); A return spring (6) is installed on the pipe (1); And a connecting rope (7) is provided on the pulley (5), one end of the connecting rope (7) is connected to the telescopic rod (2), and the other end of the connecting rope (7) passes through the pulley (5) and then through the pipe (1); Drill a blind hole on the connecting rod to the bottom of the bolt hole, so that the blind hole is connected to the bolt hole. Install the bolt into the bolt hole so that the cap of the bolt contacts the connecting rod. Insert the pipe (1) into the blind hole and pull the connecting rope (7) to make the telescopic rod (2) rotate. The telescopic rod (2) rotates until it contacts the pulley (5) and then stops rotating. Move the piston (4) to inject the hydraulic oil in the injection tube (3) into the inner cavity of the telescopic rod (2), so that the telescopic rod (2) extends and presses against the bolt. Then tighten the bolt. The extended bolt causes the telescopic rod (2) to be compressed and shortened, so that the hydraulic oil in the telescopic rod (2) enters the injection tube (3). Observe the change of the corresponding scale value of the hydraulic oil in the injection tube (3) to obtain the bolt elongation.

2. The elongation measuring instrument for connecting rod bolts of a medium-speed marine diesel engine according to claim 1, characterized in that, The telescopic rod (2) includes a first section (8), a second section (9), and a third section (10) with diameters decreasing sequentially. The inner wall of the first section (8) is provided with a groove (11) and a stop block (12). A spring (13) is provided in the groove (11). A locking block (14) is provided on the spring (13). An inclined surface is provided on the locking block (14). The second section (9) is provided with slot 2 (15), slot 3 (16) and slot 4 (17). There is a passage between slot 2 (15) and slot 3 (16), which is filled with hydraulic oil. Slot 4 (17) is provided with a second locking block (18). Slot 5 (19) and a first through hole (20) are provided deep in slot 4 (17). Slot 5 (19) is provided with a second spring (21). The third section (10) is provided with a sixth slot (22) and a third locking block (23). The sixth slot (22) is on the same straight line as the first through hole (20) and the fifth slot (19). The sixth slot (22) is provided with a fourth locking block (25) with a notch (24). When the telescopic rod (2) extends, the hydraulic oil drives the third section (10) to extend, and after the third section (10) extends, the second section (9) extends again. When the telescopic rod (2) is shortened, the second segment (9) is shortened first, and the third segment (10) is shortened after the second segment (9) is shortened.

3. The elongation measuring instrument for connecting rod bolts of a medium-speed marine diesel engine according to claim 2, characterized in that, The injection tube (3) includes a first tube (26) and a second tube (27), the diameter of the second tube (27) being greater than the diameter of the first tube (26).

4. The elongation measuring instrument for connecting rod bolts of a medium-speed marine diesel engine according to claim 3, characterized in that, The first tube (26) is provided with a fifth locking block (28), the fifth locking block (28) is provided with a groove (29) and a second through hole (30), the piston (4) enters the fifth locking block (28) at the groove (29), and the piston (4) is provided with an insertion rod that passes through the second through hole (30).

5. The elongation measuring instrument for connecting rod bolts of a medium-speed marine diesel engine according to claim 4, characterized in that, The connector of tube 1 (26) and tube 2 (27) is provided with a magnetic block 31, and the card block 5 (28) is made of a magnetic material with the opposite magnetic properties to the magnetic block 31.

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