A flexible rolling tool for thread roots and a rolling method

Abstract

The application provides a flexible rolling cutter for thread root and a rolling method, and the flexible rolling cutter comprises a rolling cutter head, an electromagnet device, a pressure sensor 16, an outer shell 9 and an inner shell 10, wherein the electromagnet device is connected with the inner shell 10 through a screw, and the outer shell 9 is slidingly connected with the inner shell 10; the rolling cutter head comprises a gasket 1, a rolling wheel 2, two bearings 3, a rolling mandrel 4, a pressing plate 5 and a fork frame 6, the fork frame 6 is in an inverted T-shaped structure as a whole, the upper end is in a U-shaped structure, the two ends of the rolling mandrel 4 are respectively installed on the left side and the right side of the U-shaped structure through the bearings 3, the rolling wheel 2 is sleeved on the rolling mandrel 4, the gasket 1 is arranged between the right side of the rolling wheel 2 and the bearing 3, the pressing plate 5 is in contact with the bearing 3 and is connected with the fork frame 6 through a screw.

Description

Technical Field

[0001] This invention relates to the field of thread rolling reinforcement technology, and in particular to a flexible rolling tool and rolling method for thread root. Background Technology

[0002] High-strength steel bolts are widely used in the assembly of critical structural components in aerospace. Because they often operate in extreme environments, higher requirements are placed on their fatigue life. Statistics show that 65% of fatigue cracks in bolts occur at the first thread when the bolt and nut are screwed together, and 20% occur at the end of the thread. For ultra-high-strength steel bolts with extremely high fatigue life requirements, the machined threads need to undergo surface strengthening treatments, such as shot peening and roll forming. Shot peening uses high-speed jets of fine shot to impact the bolt surface, causing elasto-plastic deformation of the surface material and forming a reinforced layer of a certain thickness. However, because the radius of the thread root is sub-millimeter, the space is very narrow, making it difficult for the shot to penetrate the thread root, resulting in poor uniformity of surface strengthening. Therefore, shot peening can only be used for surface strengthening of the bolt root or undercut groove, and is not suitable for surface strengthening of the thread root.

[0003] Roller burnishing is currently the main method for surface strengthening of ultra-high strength steel threads. Roller burnishing involves the continuous localized plastic deformation of the bolt surface metal under the pressure of a roller, forming a gradient microstructure and gradient grain refinement. Roller burnishing is a chip-free processing technique that does not cut the metal fibers, preserving the integrity of the metal flow lines. It effectively improves the surface quality and fatigue resistance of bolts, offering both finishing and surface strengthening benefits. Therefore, roller burnishing is widely used in enterprises to burnish the threads of ultra-high strength steel bolts.

[0004] However, the rolling roller and the bolt are in rigid contact. When the rolling roller rolls the end of the thread, the diameter of the end of the thread changes continuously. On the one hand, this will cause the rolling pressure to change, making it impossible to maintain a constant rolling pressure. On the other hand, the rolling roller will be damaged due to the sharp increase in rolling pressure. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, this invention provides a flexible rolling tool and rolling method for thread root, which enables flexible contact between the rolling wheel and the bolt and maintains constant rolling pressure during the rolling process.

[0006] In a first aspect, this application provides a flexible rolling tool for thread root, comprising a rolling head, an electromagnet device, a pressure sensor 16, a housing 9, and an inner housing 10, wherein:

[0007] The electromagnet device is connected to the inner shell 10 by screws, and the outer shell 9 is slidably connected to the inner shell 10.

[0008] The rolling cutter head includes a shim 1, a rolling roller 2, two bearings 3, a rolling mandrel 4, a pressure plate 5, and a fork 6. The fork 6 has an overall inverted T-shaped structure with a U-shaped upper end. The two ends of the rolling mandrel 4 are respectively mounted on the left and right sides of the U-shaped structure via bearings 3. The rolling roller 2 is fitted onto the rolling mandrel 4. A shim 1 is placed between the right side of the rolling roller 2 and the bearing 3. The pressure plate 5 contacts the bearing 3 and is connected to the fork 6 by screws. Two connecting bolts 8 are symmetrically distributed on the left and right sides of the fork 6, and the rolling cutter head is connected to the electromagnet device through the two connecting bolts 8. Two flexible springs 7 are respectively fitted onto the connecting bolts 8. The two bearings 3 are respectively embedded in the openings of the fork 6.

[0009] The electromagnet device includes a solenoid 11 and a main shaft 12. The main shaft 12 has a T-shaped structure, and the solenoid 11 is wound around the lower T-shaped structure of the main shaft 12. A pressure sensor 16 is disposed on the main shaft 12.

[0010] The inner shell 10 is a cylindrical structure, with two sliders (1001) symmetrically distributed on the outside of the cylindrical structure. The inner shell 10 is fitted onto the outside of the solenoid 11. The outer shell 9 is a square structure, with open upper and lower sides. Two symmetrically distributed grooves (901) are provided inside the outer shell 9, and the two grooves (901) are symmetrically distributed and contact the turret (21). The outer shell 9 is fitted onto the outside of the inner shell 10. The inner side of the outer shell 9 is provided with grooves 901, and the outer side of the inner shell 10 is provided with sliders 1001, which slide up and down along the grooves 901.

[0011] The main shaft 12 has a wire hole B15 at its T-shaped cylindrical end, and the inner shell 10 has a wire hole A14 at its lower end; the solenoid 11 is connected to the power supply wire through wire holes A14 and B15.

[0012] Specifically, the length of the solenoid 11 is equal to the length of the cylindrical end of the main shaft 12.

[0013] Specifically, the materials of the gasket 1, rolling roller 2, rolling mandrel 4, pressure plate 5 and fork 6 included in the cutter head are non-magnetic materials.

[0014] Specifically, the pressure sensor 16 is bonded to the main shaft 12, with a gap between it and the fork 6.

[0015] Specifically, the main shaft 12 and the inner housing 10 are connected by a tail screw 13.

[0016] Specifically, the flexible spring (7) can be compressed by a greater amount than the gap between the pressure sensor 16 and the fork 6.

[0017] Secondly, this application provides a flexible rolling method for the root of a thread, the method comprising:

[0018] Step 1: Clamp the high-strength steel bolt 18 to be processed on the three-jaw chuck 17 of the machine tool. The tail of the high-strength steel bolt 18 is tightened by the tail tip 20. The automatic tool setting device 19 is used for tool setting. After the automatic tool setting device 19 has finished setting the tool, the turret 21 drives the rolling cutter to enter the first thread root.

[0019] Step 2: Energize the solenoid 11 through wire holes A14 and B15. At this time, the fork 6 and the solenoid 11 form an electromagnet, and the pressure sensor 16 displays F. 电磁 The size of the rolling cutter is such that it slides to the root of the thread through the groove 901 on the housing 9, and the magnitude of the input current I is changed to make F 电磁 With preset rolling pressure F 滚 The magnitudes are equal, so obtain the rolling current I0 at this time;

[0020] Step 3: During the rolling process, the rolling current I0 is kept constant to achieve constant rolling force; the turret 21 moves axially along the high-strength steel bolt 18 to achieve rolling of the thread root;

[0021] Step 4: After the rolling is completed, disconnect the power to the solenoid 11, then retract the blade to complete the entire rolling process.

[0022] Specifically, the preset rolling pressure F 滚 The range refers to the magnitude of the rolling force used in the project, with a value of 0-600N.

[0023] In summary, the present invention provides a flexible rolling tool and rolling method for thread root, which has the following advantages compared with the prior art:

[0024] Because this invention uses an electromagnet device to utilize electromagnetic force F 电磁 To drive the rolling roller to roll high-strength bolts, the specific steps are as follows: First, the high-strength steel bolt 18 to be rolled is clamped on the three-jaw chuck 17 of the machine tool, with the tail end tightened by the tailstock tip 20. An automatic tool setting device 19 is used for tool setting. After the automatic tool setting device 19 completes tool setting, the turret 21 drives the rolling tool into the first thread root. Then, the solenoid 11 is energized through wire holes A14 and B15. At this time, the spindle 12 and the solenoid 11 form an electromagnet. The cylindrical section of the spindle 12 is equivalent to the core of the electromagnet, and the electromagnet outputs an electromagnetic force F. 电磁 Pressure sensor 16 displays F 电磁 Size, F 电磁The high-strength steel bolt 18 is attracted by the three-jaw chuck 17, and the rolling cutter slides to the thread root through the groove 901 on the housing 9, compressing the thread root of the high-strength steel bolt 18. By changing the magnitude of the input current I, F... 电磁 With the required rolling pressure F 滚 The magnitudes are equal, and the rolling current I0 is obtained at this time; during the rolling process, the magnitude of the rolling current I0 remains unchanged, the turret 21 moves along the axis of the high-strength steel bolt 18 to achieve the rolling of the thread root, after the rolling is completed, the solenoid 11 is de-energized, and then the tool is retracted, the whole rolling process ends, realizing the flexible contact between the rolling wheel and the high-strength steel bolt to be processed and the constant force rolling of the thread root. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of a flexible rolling tool for thread root provided by the present invention;

[0026] Figure 2 This is a left view of a flexible rolling tool for thread root provided by the present invention;

[0027] Figure 3 This is a schematic diagram of the A-direction structure of a flexible rolling tool for thread root provided by the present invention.

[0028] Figure 4 This is a partially enlarged schematic diagram of section B of a flexible rolling tool for thread root provided by the present invention;

[0029] Figure 5 This is a schematic diagram of automatic tool setting during workpiece machining.

[0030] Figure 6 yes Figure 5 Left view of the turret and cutting tools.

[0031] In the diagram: 1-shim, 2-rolling roller, 3-bearing, 4-rolling spindle, 5-pressure plate, 6-fork, 7-flexible spring, 8-connecting bolt, 9-outer shell, 901-slide groove, 10-inner shell, 1001-slider, 11-sowary, 12-spindle, 13-tail screw, 14-wire hole A, 15-wire hole B, 16-pressure sensor, 17-three-jaw chuck, 18-high-strength steel bolt, 19-automatic tool setting device, 20-tail tip center, 21-turret. Detailed Implementation

[0032] like Figure 1-2 As shown, this application provides a flexible rolling tool for thread root, including a rolling head, an electromagnet device, a pressure sensor 16, a housing 9, and an inner housing 10, wherein:

[0033] The electromagnet device is connected to the inner shell 10 by screws, and the outer shell 9 is slidably connected to the inner shell 10.

[0034] The rolling cutter head includes a shim 1, a rolling roller 2, two bearings 3, a rolling mandrel 4, a pressure plate 5, and a fork 6. The fork 6 has an overall inverted T-shaped structure with a U-shaped upper end. The two ends of the rolling mandrel 4 are respectively mounted on the left and right sides of the U-shaped structure via bearings 3. The rolling roller 2 is fitted onto the rolling mandrel 4. A shim 1 is placed between the right side of the rolling roller 2 and the bearing 3. The pressure plate 5 contacts the bearing 3 and is connected to the fork 6 by screws. Two connecting bolts 8 are symmetrically distributed on the left and right sides of the fork 6, and the rolling cutter head is connected to the electromagnet device through the two connecting bolts 8. Two flexible springs 7 are respectively fitted onto the connecting bolts 8. The two bearings 3 are respectively embedded in the openings of the fork 6.

[0035] The electromagnet device includes a solenoid 11 and a main shaft 12. The main shaft 12 has a T-shaped structure, and the solenoid 11 is wound around the lower T-shaped structure of the main shaft 12. A pressure sensor 16 is disposed on the main shaft 12.

[0036] The inner shell 10 is a cylindrical structure, with two sliders (1001) symmetrically distributed on the outside of the cylindrical structure. The inner shell 10 is fitted onto the outside of the solenoid 11. The outer shell 9 is a square structure, with open top and bottom sides. Two symmetrically distributed grooves (901) are provided inside the outer shell 9, symmetrically positioned to contact the turret (21), and fitted onto the outside of the inner shell 10. The inner side of the outer shell 9 has grooves 901, and the outer side of the inner shell 10 has sliders 1001. The sliders 1001 slide up and down along the grooves 901. Figure 3-4 As shown;

[0037] The main shaft 12 has a wire hole B15 at its T-shaped cylindrical end, and the inner shell 10 has a wire hole A14 at its lower end; the solenoid 11 is connected to the power supply wire through wire holes A14 and B15.

[0038] Furthermore, the materials of the gasket 1, rolling roller 2, rolling mandrel 4, pressure plate 5 and fork 6 included in the cutter head are non-magnetic materials.

[0039] Furthermore, the pressure sensor 16 is bonded to the main shaft 12, with a gap between it and the fork 6.

[0040] Furthermore, the main shaft 12 is connected to the inner housing 10 by a tail screw 13.

[0041] Furthermore, the flexible spring (7) can be compressed by a greater amount than the gap between the pressure sensor 16 and the fork 6.

[0042] Furthermore, the pressure sensor 16 is matched with a display screen, which can display the pressure value in real time.

[0043] Furthermore, the length of the solenoid 11 is equal to the length of the cylindrical end of the spindle 12.

[0044] Example 2

[0045] like Figure 5-6 As shown, this application provides a rolling method for a flexible rolling tool used for thread root, comprising the following steps:

[0046] Step 1: Clamp the high-strength steel bolt 18 to be processed on the three-jaw chuck 17 of the machine tool. The tail of the high-strength steel bolt 18 is tightened by the tail tip 20. The automatic tool setting device 19 is used for tool setting. After the automatic tool setting device 19 has finished setting the tool, the turret 21 drives the rolling cutter to enter the first thread root.

[0047] Step 2: Energize the solenoid 11 through wire holes A14 and B15. At this time, the fork 6 and the solenoid 11 form an electromagnet, and the pressure sensor 16 displays F. 电磁 The size of the rolling cutter is such that it slides to the root of the thread through the groove 901 on the housing 9, and the magnitude of the input current I is changed to make F 电磁 With preset rolling pressure F 滚 The magnitudes are equal, so obtain the rolling current I0 at this time;

[0048] Among them, the preset rolling pressure F 滚 The range refers to the magnitude of the rolling force used in the project, with a value of 0-600N.

[0049] It should be noted that the cylindrical section of the fork 6 is equivalent to the iron core of the electromagnet, and the electromagnet outputs an electromagnetic force F. 电磁 Pressure sensor 16 displays F 电磁 Size, F 电磁 The high-strength steel bolt 18 is attracted by the three-jaw chuck 17, and the rolling cutter slides to the root of the thread through the groove 901 on the housing 9.

[0050] Step 3: During the rolling process, the rolling current I0 is kept constant to achieve constant rolling force; the turret 21 moves axially along the high-strength steel bolt 18 to achieve rolling of the thread root;

[0051] Step 4: After the rolling is completed, disconnect the power to the solenoid 11, then retract the blade to complete the entire rolling process.

[0052] In summary, the present invention provides a flexible rolling tool and rolling method for thread root, which has the following advantages compared with the prior art:

[0053] Because this invention uses an electromagnet device to utilize electromagnetic force F 电磁 To drive the rolling roller to roll high-strength bolts, the specific steps are as follows: First, the high-strength steel bolt 18 to be rolled is clamped on the three-jaw chuck 17 of the machine tool, with the tail end tightened by the tailstock tip 20. An automatic tool setting device 19 is used for tool setting. After the automatic tool setting device 19 completes tool setting, the turret 21 drives the rolling tool into the first thread root. Then, the solenoid 11 is energized through wire holes A14 and B15. At this time, the fork 6 and the solenoid 11 form an electromagnet. The cylindrical section of the fork 6 is equivalent to the core of the electromagnet, and the electromagnet outputs an electromagnetic force F. 电磁 Pressure sensor 16 displays F 电磁 Size, F 电磁 The high-strength steel bolt 18 is attracted by the three-jaw chuck 17, and the rolling cutter slides to the root of the thread through the groove 901 on the housing 9. By changing the magnitude of the input current I, F... 电磁 With the required rolling pressure F 滚 The magnitudes are equal, and the rolling current I0 is obtained at this time; during the rolling process, the magnitude of the rolling current I0 remains unchanged, the turret 21 moves along the axis of the high-strength steel bolt 18 to achieve the rolling of the thread root, after the rolling is completed, the solenoid 11 is de-energized, and then the tool is retracted, the whole rolling process ends, realizing the flexible contact between the rolling wheel and the high-strength steel bolt to be processed and the constant force rolling of the thread root.

Claims

1. A flexible rolling tool for thread root, characterized in that, Includes a rolling cutter head, an electromagnet device, a pressure sensor (16), a housing (9), and an inner housing (10), wherein: The electromagnet device is connected to the inner shell (10) by screws, and the outer shell (9) is slidably connected to the inner shell (10); The rolling cutter head includes a shim (1), a rolling roller (2), two bearings (3), a rolling mandrel (4), a pressure plate (5), and a fork (6). The fork (6) has an overall inverted T-shaped structure with a U-shaped upper end. The two ends of the rolling mandrel (4) are respectively installed on the left and right sides of the U-shaped structure through the bearings (3). The rolling roller (2) is fitted onto the rolling mandrel (4). A shim (1) is provided between the right side of the rolling roller (2) and the bearing (3). The pressure plate (5) contacts the bearing (3) and is connected to the fork (6) by screws. Two connecting bolts (8) are symmetrically distributed on the left and right sides of the fork (6), and the rolling cutter head is connected to the electromagnet device through the two connecting bolts (8). Two flexible springs (7) are respectively fitted onto the connecting bolts (8). The two bearings (3) are respectively embedded in the openings of the fork (6). The electromagnet device includes a solenoid (11) and a main shaft (12). The main shaft (12) has a T-shaped structure, and the solenoid (11) is wound around the lower T-shaped structure of the main shaft (12). A pressure sensor (16) is mounted on the main shaft (12). The inner shell (10) is a cylindrical structure, with two sliders (1001) symmetrically distributed on the outside of the cylindrical structure. The inner shell (10) is fitted onto the outside of the solenoid (11). The outer shell (9) is a square structure, with the upper and lower sides of the outer shell (9) being open. Two symmetrically distributed grooves (901) are provided inside the outer shell (9). The two grooves (901) are symmetrically distributed and contact the turret (21), and are fitted onto the outside of the inner shell (10). The inner side of the outer shell (9) is provided with grooves (901), and the outer side of the inner shell (10) is provided with sliders (1001). The sliders (1001) slide up and down along the grooves (901). The main shaft (12) has a wire hole B (15) at its T-shaped cylindrical end, and the inner shell (10) has a wire hole A (14) at its lower end; the solenoid (11) is connected to the power supply wire through the wire hole A (14) and the wire hole B (15); the length of the solenoid (11) is equal to the length of the cylindrical end of the main shaft (12).

2. The flexible rolling cutter according to claim 1, characterized in that, The materials of the gasket (1), rolling roller (2), rolling mandrel (4), pressure plate (5) and fork (6) contained in the cutter head are non-magnetic materials.

3. The flexible rolling cutter according to claim 1, characterized in that, The pressure sensor (16) is bonded to the main shaft (12) with a gap between it and the fork (6).

4. The flexible rolling cutter according to claim 1, characterized in that, The main shaft (12) is connected to the inner shell (10) by a tail screw (13).

5. The flexible rolling cutter according to claim 1, characterized in that, The flexible spring (7) can be compressed to a greater extent than the gap between the pressure sensor (16) and the fork (6).

6. A flexible rolling method for thread root, characterized in that, The method is implemented using the flexible rolling tool for thread root as described in any one of claims 1 to 5, and the method includes: Step 1: Clamp the high-strength steel bolt (18) to be processed on the three-jaw chuck (17) of the machine tool. The tail of the high-strength steel bolt (18) is tightened by the tail tip (20). The automatic tool setting device (19) is used for tool setting. After the automatic tool setting device (19) has finished setting the tool, the turret (21) drives the rolling tool to enter the first thread root. Step 2: Energize the solenoid (11) through wire hole A (14) and wire hole B (15). At this time, the fork (6) and the solenoid (11) form an electromagnet, and the pressure sensor (16) displays F. 电磁 The size of the rolling cutter is such that it slides to the root of the thread through the groove (901) on the housing (9), and by changing the magnitude of the input current I, F is made... 电磁 With preset rolling pressure F 滚 The magnitudes are equal, so obtain the rolling current I0 at this time; Step 3: During the rolling process, the rolling current I0 is kept constant to achieve constant rolling force; the turret (21) moves axially along the high-strength steel bolt (18) to achieve rolling of the thread root; Step 4: After the rolling is completed, turn off the power to the solenoid (11), and then retract the blade to complete the entire rolling process.

7. The flexible rolling method according to claim 6, characterized in that, Preset rolling pressure F 滚 The range refers to the magnitude of the rolling force used in the project, with a value of 0-600N.

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