Device for taking out fractured cylinder cover bolt

Abstract

A device for taking out a fractured cylinder cover bolt comprises a connecting sleeve, the connecting sleeve comprises a positioning sleeve and an outer hexagon nut which are integrally connected, the diameter of the lower portion of the positioning sleeve is gradually reduced to form a conical contraction opening, the lower portion of the positioning sleeve extends into a counter bore of a cylinder body, and the end of the conical contraction opening is fixedly welded to the upper portion of the fractured bolt. A through hole is formed in the center of the sealing cover, and a nitrogen charging connector is arranged at the center of the sealing cover; according to the device, one end of a connecting sleeve extends into a counter bore of a cylinder body to be welded and fixed to a fracture opening of a fractured bolt, the other end of the connecting sleeve is sealed through a sealing cover, a closed inner cavity is formed in the connecting sleeve, liquid nitrogen is injected through a nitrogen charging connector in the sealing cover, and by means of the low-temperature characteristic of the liquid nitrogen and the thermal expansion and cold contraction characteristic of metal, the fractured bolt shrinks when cooled; the connection strength with the cylinder body is reduced, the broken bolt can be conveniently screwed out in cooperation with a connecting sleeve, the threaded hole structure of the cylinder body cannot be damaged, and the operation effect is good.

Description

Technical Field

[0001] The utility model relates to a device for removing broken cylinder cover bolts. Background Art

[0002] The bolts connecting the engine cylinder block and cylinder head may sometimes break due to impact vibration caused by various faults such as the crankshaft, piston, and connecting rod. Since tightening the main bolts of the engine cylinder head is different from other bolts, in order to ensure the sealing of the cylinder head, withstand the strong air pressure in the engine, and prevent the bolts from loosening and rotating and causing accidents, the bottom bolt head needs to have a very large force to press against the end of the cylinder block screw hole. This force is quite large. Once the bolt breaks in the cylinder body, due to the strong tightening force of the main bolts on the cylinder head and the deep bolt holes, it is impossible to remove the broken bolts by conventional broken nail removal methods. The existing authorization announcement number is CN110961859B A Chinese utility model patent discloses a device and method for repairing broken bolts connecting an engine cylinder head and a cylinder block. The device uses a matching set of the limiting sleeve and the milling cutter, and uses a milling cutter with a diameter smaller than the minor diameter of the broken bolt thread to mill into the broken bolt to prevent the thread of the screw hole from being damaged and the inner diameter of the broken screw from being completely milled off, which makes it difficult to remove the broken screw thread; and the tightening head of the broken bolt is broken, and the original pre-tightening force of the threaded part of the broken bolt is eliminated, thereby facilitating the smooth removal of the threaded part. Although this method can remove the broken thread, it has very high requirements on the dimensional accuracy of the limiting sleeve and the milling cutter. A slight deviation can easily damage the threaded hole in the cylinder body, affecting the subsequent use of the cylinder body. Utility Model Content

[0003] In view of the shortcomings existing in the above problems, the utility model provides a device for removing broken cylinder head bolts.

[0004] To achieve the above-mentioned purpose, the utility model provides a device for removing broken cylinder head bolts, comprising a connecting sleeve, wherein the connecting sleeve comprises an integrally connected positioning sleeve and an external hexagonal nut, a step portion is formed at the connection between the positioning sleeve and the external hexagonal nut, the diameter of the lower portion of the positioning sleeve gradually decreases to form a tapered contraction opening, the lower portion of the positioning sleeve extends into the countersunk hole of the cylinder body, the end portion of the tapered contraction opening is welded and fixed to the upper portion of the broken bolt, a sealing cover is installed on the upper portion of the external hexagonal nut, a through hole is processed at the center of the sealing cover and a nitrogen filling joint is provided.

[0005] As a further improvement of the present invention, the outer diameter of the positioning sleeve matches the inner diameter of the countersunk hole, the length of the positioning sleeve is greater than the height of the upper end of the broken bolt from the upper edge of the countersunk hole, and the diameter of the lower part of the conical contraction mouth is smaller than the large diameter of the broken bolt.

[0006] As a further improvement of the present invention, a welding-proof sheath is provided at the connection between the step portion and the inner hole of the positioning sleeve.

[0007] As a further improvement of the present invention, the outer peripheral surface of the lower part of the cover is processed with an external thread that matches and screws with the internal thread on the inner side of the external hexagonal nut. A sealing ring is provided at the junction of the edge of the cover and the external hexagonal nut. An annular groove is processed on the upper part of the external hexagonal nut, and the sealing ring is built into the annular groove. The depth of the annular groove is less than the diameter of the sealing ring.

[0008] The beneficial effects of the utility model are:

[0009] 1. The utility model extends the positioning sleeve at one end of the connecting sleeve into the countersunk hole of the cylinder body, and the end of the positioning sleeve is provided with a tapered shrinkage opening which is welded to the fracture opening of the broken bolt. The other end of the connecting sleeve is sealed by a sealing cover, thereby forming a closed inner cavity in the connecting sleeve. Liquid nitrogen is then injected through the nitrogen filling interface on the sealing cover. By utilizing the low temperature characteristics of liquid nitrogen and the thermal expansion and contraction characteristics of metal, the broken bolt contracts when it is cooled, and the connection strength with the cylinder body is reduced, making it easy to unscrew the broken bolt as a whole with the connecting sleeve without damaging the threaded hole structure of the cylinder body, and achieving a good operating effect.

[0010] 2. A welding shield is provided on the inner edge of the step portion of the connecting sleeve to prevent the welding rod from adhering to the inner wall of the connecting sleeve during welding, thereby ensuring point welding. The welding shield can be removed after welding is completed. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a front view of a device for removing broken cylinder head bolts according to the present invention;

[0012] Figure 2 It is a top view of the connecting sleeve 1.

[0013] In the figure: 1. Connecting sleeve; 11. Positioning sleeve; 12. External hexagonal nut; 121. Internal thread; 13. Conical contraction mouth; 14. Step portion; 15. Annular groove; 2. Cover; 21. Through hole; 22. Nitrogen charging connector; 23. External thread; 3. Sealing ring; 4. Welding shield; 5. Cylinder body; 51. Countersunk hole; 52. Threaded hole; 6. Broken bolt. DETAILED DESCRIPTION

[0014] like Figure 1-2As shown, the utility model is a device for removing a broken cylinder head bolt, comprising a connecting sleeve 1, the connecting sleeve 1 comprising an integrally connected positioning sleeve 11 and an outer hexagonal nut 12, a step portion 14 is formed at the connection between the positioning sleeve 11 and the outer hexagonal nut 12, a welding shield 4 is provided at the connection between the step portion 14 and the inner hole of the positioning sleeve 11, the diameter of the lower portion of the positioning sleeve 11 gradually decreases to form a tapered contraction 13, the lower portion of the positioning sleeve 11 extends into the countersunk hole 51 of the cylinder body 5, the end of the tapered contraction 13 is welded and fixed to the upper portion of the broken bolt 6, the outer diameter of the positioning sleeve 11 matches the inner diameter of the countersunk hole 51, and the positioning sleeve 11 is fixed to the upper portion of the broken bolt 6. The length of the positioning sleeve 11 is greater than the height from the upper end of the broken bolt 6 to the upper edge of the countersunk hole 51. The lower diameter of the tapered contraction mouth 13 is smaller than the major diameter of the broken bolt 6. The cover 2 is installed on the upper part of the external hexagonal nut 12. A through hole 21 is processed at the center of the cover 2 and a nitrogen filling joint 22 is provided. The outer peripheral surface of the lower part of the cover 2 is processed with an external thread 23 that matches and screws with the internal thread 121 on the inner side of the external hexagonal nut 12. A sealing ring 3 is provided at the junction of the cover 2 and the external hexagonal nut 12. An annular groove 15 is processed on the upper part of the external hexagonal nut 12. The sealing ring 3 is built into the annular groove 15. The depth of the annular groove 15 is less than the diameter of the sealing ring 3.

[0015] The utility model extends the positioning sleeve at one end of the connecting sleeve into the countersunk hole of the cylinder body, and the end of the positioning sleeve is provided with a tapered shrinkage opening which is welded and fixed to the fracture opening of the broken bolt. The other end of the connecting sleeve is sealed by a sealing cover, thereby forming a closed inner cavity in the connecting sleeve, and then injecting liquid nitrogen through the nitrogen filling interface on the sealing cover. By utilizing the low temperature characteristics of liquid nitrogen and the thermal expansion and contraction characteristics of metal, the broken bolt contracts when it is cooled, and the connection strength with the cylinder body is reduced, which makes it easy to cooperate with the connecting sleeve to screw out the broken bolt as a whole without damaging the threaded hole structure of the cylinder body, and the operation effect is good. The inner edge of the step portion in the connecting sleeve is provided with a welding shield, which prevents the welding rod from adhering to the inner wall surface of the connecting sleeve during welding, ensures the realization of fixed-point welding, and the welding shield can be removed after welding is completed.

[0016] During the specific processing, in order to facilitate the understanding of the present invention, the following description is given in conjunction with the accompanying drawings;

[0017] The work includes the following steps:

[0018] (1) Positioning the connecting sleeve: Select an appropriate connecting sleeve according to the size of the countersunk hole and the height of the broken bolt from the upper edge of the countersunk hole. Install a welding shield on the inner edge of the step portion of the connecting sleeve. Then, extend the positioning sleeve at the bottom of the connecting sleeve into the countersunk hole of the cylinder body. The conical contraction port at the bottom of the positioning sleeve contacts the broken bolt.

[0019] (2) Welding: Insert the welding rod obliquely from top to bottom into the positioning sleeve, with the lower end of the welding rod close to the connection position of the conical contraction port and the broken bolt, and then vertically extend the welding gun into the positioning sleeve. The welding rod is melted by the high temperature formed by the welding gun and welded to the connection position of the conical contraction port and the broken bolt. After the welding is completed, wait for the welding position to cool down, and the welding shield can be removed or not;

[0020] (3) Nitrogen filling and cooling: A sealing ring is installed in the annular groove on the outer hexagonal nut on the upper part of the connecting sleeve, and then a sealing cover is installed. The sealing cover and the outer hexagonal nut are screwed together and fixed by a threaded structure. The edge of the sealing cover is pressed against the sealing ring to form a sealing effect. A closed inner cavity is formed in the connecting sleeve. Liquid nitrogen is injected into the closed inner cavity through the nitrogen filling interface on the sealing cover by a nitrogen filling machine. By utilizing the low temperature characteristics of liquid nitrogen and the thermal expansion and contraction characteristics of metal, the broken screw will shrink as a whole under the action of liquid nitrogen, and the connection strength between the broken screw and the threaded hole of the cylinder body is reduced;

[0021] (4) Remove the bolt: Directly turn the outer hexagonal nut on the upper part of the connecting sleeve to unscrew the broken screw out of the threaded hole in the cylinder body.

[0022] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A device for removing broken cylinder head bolts, characterized by: The invention comprises a connecting sleeve (1), wherein the connecting sleeve (1) comprises an integrally connected positioning sleeve (11) and an external hexagonal nut (12), a step portion (14) is formed at the connection between the positioning sleeve (11) and the external hexagonal nut (12), the diameter of the lower portion of the positioning sleeve (11) gradually decreases to form a conical contraction opening (13), the lower portion of the positioning sleeve (11) extends into a counterbore (51) of a cylinder body (5), the end of the conical contraction opening (13) is welded and fixed to the upper portion of a broken bolt (6), a cover (2) is installed on the upper portion of the external hexagonal nut (12), a through hole (21) is processed at the center of the cover (2) and a nitrogen charging joint (22) is provided.

2. The device for removing a broken cylinder head bolt according to claim 1, characterized in that: The outer diameter of the positioning sleeve (11) matches the inner diameter of the countersunk hole (51), the length of the positioning sleeve (11) is greater than the height of the upper end of the broken bolt (6) from the upper edge of the countersunk hole (51), and the lower diameter of the conical contraction opening (13) is smaller than the major diameter of the broken bolt (6).

3. The device for removing a broken cylinder head bolt according to claim 1, characterized in that: A welding-proof sheath (4) is provided at the connection between the step portion (14) and the inner hole of the positioning sleeve (11).

4. The device for removing a broken cylinder head bolt according to claim 1, characterized in that: The outer peripheral surface of the lower portion of the cover (2) is processed with an external thread (23) that is matched and screwed with the internal thread (121) on the inner side of the external hexagonal nut (12); a sealing ring (3) is provided at the junction of the cover (2) and the external hexagonal nut (12); an annular groove (15) is processed on the upper portion of the external hexagonal nut (12); the sealing ring (3) is built into the annular groove (15); and the depth of the annular groove (15) is less than the diameter of the sealing ring (3).

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