Flexible rolling cutter for thread root and rolling method

Abstract

The invention provides a flexible rolling cutter and a rolling method for a thread root, 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, the electromagnet device is connected with the inner shell 10 through a screw, and the outer shell 9 is slidably connected with the inner shell 10; the rolling tool bit 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 whole fork frame 6 is of an inverted T-shaped structure, the upper end of the fork frame 6 is of a U-shaped structure, and the two ends of the rolling mandrel 4 are installed on the left side and the right side of the U-shaped structure through the bearings 3 respectively; 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; and 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] The invention relates to the technical field of thread rolling strengthening, in particular to a flexible rolling tool and a rolling method for thread roots. Background Art

[0002] High-strength steel bolts are widely used in the assembly of important structural parts in aerospace. Since they are mostly used in extreme environments, higher requirements are placed on the fatigue life of bolts. Statistics show that 65% of fatigue cracks occur at the first thread of the bolt and nut when the bolt is fatigue-fractured, and 20% of fatigue cracks occur at the end of the thread. For ultra-high-strength steel bolts with very high fatigue life requirements, the threads after turning need to be subjected to surface strengthening treatments, such as shot peening and rolling strengthening. Shot peening is the use of high-speed spray of fine projectiles to impact the surface of the sprayed bolt, causing elastic-plastic deformation of the surface material of the bolt to form a strengthening layer of a certain thickness. Since the radius of the arc at the bottom of the thread is sub-millimeter and the space is very narrow, it is difficult for the projectile to enter the bottom of the thread, and the uniformity of the surface strengthening is poor. Therefore, shot peening can only be used for the surface strengthening of the bolt root or the backing groove, but not for the surface strengthening treatment of the thread bottom.

[0003] Rolling strengthening is currently the main method for surface strengthening of ultra-high strength steel threads. Rolling strengthening is to make the metal on the surface of the bolt produce continuous local plastic deformation under the action of the rolling wheel pressure, forming a gradient microstructure and gradient refined grains. Rolling strengthening is a chipless processing technology that does not cut the metal fibers and keeps the metal flow lines intact. It can effectively improve the surface quality and fatigue resistance of the bolt, and has the dual functions of finishing and surface strengthening. Therefore, most companies currently use rolling wheels to roll the threaded parts of ultra-high strength steel bolts.

[0004] However, the rolling wheel and the bolt are in rigid contact. When the rolling wheel rolls the end of the thread, the diameter of the end of the thread changes continuously, which will cause the rolling force to change and make it impossible to maintain a constant rolling force. On the other hand, the rolling wheel will be damaged due to the sharp increase in rolling force. Summary of the invention

[0005] In order to solve the above-mentioned problems existing in the prior art, the present invention provides a flexible rolling tool and rolling method for the thread root, which can achieve flexible contact between the rolling wheel and the bolt and maintain a constant rolling force during the rolling process.

[0006] In a first aspect, the present application provides a flexible rolling tool for a thread root, comprising a rolling tool head, an electromagnet device, a pressure sensor 16, an outer shell 9 and an inner shell 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 gasket 1, a rolling wheel 2, two bearings 3, a rolling mandrel 4, a pressure plate 5 and a fork frame 6. The fork frame 6 is an inverted T-shaped structure as a whole, and the upper end is a U-shaped structure. The two ends of the rolling mandrel 4 are respectively installed on the left and right sides of the U-shaped structure through bearings 3; the rolling wheel 2 is sleeved on the rolling mandrel 4; a gasket 1 is arranged between the right side of the rolling wheel 2 and the bearing 3; the pressure plate 5 is in contact with the bearing 3 and is connected to the fork frame 6 by screws; two connecting bolts 8 are symmetrically distributed on the left and right sides of the fork frame 6, and the rolling cutter head is connected to the electromagnet device by two connecting bolts 8; two flexible springs 7 are respectively sleeved on the connecting bolts 8; and two bearings 3 are respectively embedded in the openings of the fork frame 6;

[0009] The electromagnet device comprises a solenoid 11 and a main shaft 12, wherein the main shaft 12 is in a T-shaped structure, and the solenoid 11 is wound around the T-shaped lower end structure of the main shaft 12; a pressure sensor 16 is arranged on the main shaft 12;

[0010] The inner shell 10 is a cylindrical structure, and two sliders (1001) are symmetrically distributed on the outer side of the cylindrical structure, and the inner shell 10 is sleeved on the outer side of the solenoid 11; the outer shell 9 is a square structure, and the upper and lower sides of the outer shell 9 are transparent, and two symmetrically distributed slide grooves (901) are arranged inside the outer shell 9, and the two slide grooves (901) are symmetrically distributed and contact the turret (21), and are sleeved on the outer side of the inner shell 10; the slide groove 901 is arranged on the inner side of the outer shell 9, and the slider 1001 is arranged on the outer side of the inner shell 10, and the slider 1001 slides up and down along the slide groove 901;

[0011] The T-shaped cylindrical end of the main shaft 12 is provided with a wire hole B15, and the lower end of the inner shell 10 is provided with a wire hole A14; the solenoid 11 is connected to the power supply wire through the wire hole A14 and the wire hole 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 gasket 1, the rolling wheel 2, the rolling mandrel 4, the pressing plate 5 and the fork frame 6 included in the cutter head are made of non-magnetic materials.

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

[0015] Specifically, the main shaft 12 is connected to the inner housing 10 via a tail screw 13 .

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

[0017] In a second aspect, the present application provides a flexible rolling method for a thread root, 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, tighten the tail of the high-strength steel bolt 18 by the tail tip 20, and use the automatic tool setting device 19 to set the tool. When the automatic tool setting device 19 has finished setting the tool, the turret 21 drives the rolling tool to enter the first thread root;

[0019] Step 2: Power the solenoid 11 through the wire holes A14 and B15. At this time, the fork frame 6 and the solenoid 11 form an electromagnet, and the pressure sensor 16 displays F. 电磁 The rolling tool slides to the bottom of the thread through the slide groove 901 on the housing 9, and by changing the input current I, F 电磁 With the preset rolling force F 滚 The magnitudes of are equal, and the rolling current I0 at this time is obtained;

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

[0021] Step 4: After the rolling is completed, the solenoid 11 is powered off, and then the knife is withdrawn to complete the entire rolling process.

[0022] Specifically, the preset rolling force F 滚 The range is the size of the rolling force used in the project, and the value is 0-600N.

[0023] In summary, the present invention provides a flexible rolling tool and rolling method for thread bottom. Compared with the prior art, the present invention has the following beneficial effects:

[0024] Since the present invention adopts an electromagnet device to utilize electromagnetic force F 电磁 To drive the rolling wheel to roll the high-strength bolt, the specific steps are: first clamp the high-strength steel bolt 18 to be rolled on the three-jaw chuck 17 of the machine tool, tighten the tail with the tail tip 20, and use the automatic tool setting device 19 to set the tool. When the automatic tool setting device 19 is finished, the turret 21 drives the rolling tool to enter the first thread bottom; then the solenoid 11 is energized through the wire hole A14 and the wire hole B15. At this time, the spindle 12 and the solenoid 11 form an electromagnet, and the cylindrical section of the spindle 12 is equivalent to the iron core of the electromagnet. The electromagnet outputs an electromagnetic force F 电磁 , pressure sensor 16 shows F 电磁 Size, F 电磁The high-strength steel bolt 18 is attracted. Since the high-strength steel bolt 18 to be processed is fixed on the three-jaw chuck 17, the rolling tool slides to the bottom of the thread through the slide groove 901 on the housing 9, and the bottom of the thread of the high-strength steel bolt 18 is squeezed. By changing the size of the input current I, F 电磁 and the required rolling force F 滚 is equal to the magnitude of , and the rolling current I0 at this time is obtained; during the rolling process, the magnitude of the rolling current I0 is kept unchanged, and the turret 21 moves axially along the high-strength steel bolt 18 to realize the rolling of the thread root. After the rolling is completed, the solenoid 11 is powered off, and then the tool is retracted, and the entire rolling process is completed, 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of a flexible rolling tool for thread bottom provided by the present invention;

[0026] Figure 2 It 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-axis structure of a flexible rolling tool for thread bottom provided by the present invention.

[0028] Figure 4 It is a partial enlarged schematic diagram of position B of a flexible rolling tool for thread bottom 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 tool.

[0031] In the figure: 1-gasket, 2-rolling wheel, 3-bearing, 4-rolling mandrel, 5-pressure plate, 6-fork frame, 7-flexible spring, 8-connecting bolt, 9-outer shell, 901-slide groove, 10-inner shell, 1001-slider, 11-solenoid, 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 center, 21-turret. DETAILED DESCRIPTION

[0032] like Figure 1-2 As shown, the present application provides a flexible rolling tool for thread root, including a rolling tool head, an electromagnet device, a pressure sensor 16, an outer shell 9 and an inner shell 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 gasket 1, a rolling wheel 2, two bearings 3, a rolling mandrel 4, a pressure plate 5 and a fork frame 6. The fork frame 6 is an inverted T-shaped structure as a whole, and the upper end is a U-shaped structure. The two ends of the rolling mandrel 4 are respectively installed on the left and right sides of the U-shaped structure through bearings 3; the rolling wheel 2 is sleeved on the rolling mandrel 4; a gasket 1 is arranged between the right side of the rolling wheel 2 and the bearing 3; the pressure plate 5 is in contact with the bearing 3 and is connected to the fork frame 6 by screws; two connecting bolts 8 are symmetrically distributed on the left and right sides of the fork frame 6, and the rolling cutter head is connected to the electromagnet device by two connecting bolts 8; two flexible springs 7 are respectively sleeved on the connecting bolts 8; and two bearings 3 are respectively embedded in the openings of the fork frame 6;

[0035] The electromagnet device comprises a solenoid 11 and a main shaft 12, wherein the main shaft 12 is in a T-shaped structure, and the solenoid 11 is wound around the T-shaped lower end structure of the main shaft 12; a pressure sensor 16 is arranged on the main shaft 12;

[0036] The inner shell 10 is a cylindrical structure, and two sliders (1001) are symmetrically distributed on the outside of the cylindrical structure. The inner shell 10 is sleeved on the outside of the solenoid 11; the outer shell 9 is a square structure, and the upper and lower sides of the outer shell 9 are transparent. Two symmetrically distributed slide grooves (901) are arranged inside the outer shell 9, and the two slide grooves (901) are symmetrically distributed and contact the turret (21) and are sleeved on the outside of the inner shell 10; the slide groove 901 is arranged on the inner side of the outer shell 9, and the slider 1001 is arranged on the outer side of the inner shell 10, and the slider 1001 slides up and down along the slide groove 901, as shown in FIG. Figure 3-4 As shown;

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

[0038] Furthermore, the material of the gasket 1, the rolling wheel 2, the rolling mandrel 4, the pressing plate 5 and the fork frame 6 included in the cutter head is a non-magnetic material.

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

[0040] Furthermore, the main shaft 12 and the inner housing 10 are connected via a tail screw 13 .

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

[0042] Furthermore, the pressure sensor 16 is matched with a display screen and 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 main shaft 12 .

[0044] Embodiment 2

[0045] like Figure 5-6 As shown, the present application provides a rolling method of a flexible rolling tool for a thread bottom, 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, tighten the tail of the high-strength steel bolt 18 by the tail tip 20, and use the automatic tool setting device 19 to set the tool. When the automatic tool setting device 19 has finished setting the tool, the turret 21 drives the rolling tool to enter the first thread root;

[0047] Step 2: Power the solenoid 11 through the wire holes A14 and B15. At this time, the fork frame 6 and the solenoid 11 form an electromagnet, and the pressure sensor 16 displays F. 电磁 The rolling tool slides to the bottom of the thread through the slide groove 901 on the housing 9, and by changing the input current I, F 电磁 With the preset rolling force F 滚 The magnitudes of are equal, and the rolling current I0 at this time is obtained;

[0048] Among them, the preset rolling pressure F 滚 The range is the size of the rolling force used in the project, and the value is 0-600N.

[0049] It should be noted that the cylindrical section of the fork frame 6 is equivalent to the iron core of the electromagnet, and the electromagnet outputs the electromagnetic force F 电磁 , pressure sensor 16 shows F 电磁 Size, F 电磁 An attractive force is generated on the high-strength steel bolt 18 . Since the high-strength steel bolt 18 to be processed is fixed on the three-jaw chuck 17 , the rolling tool slides to the bottom of the thread through the slide groove 901 on the housing 9 .

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

[0051] Step 4: After the rolling is completed, the solenoid 11 is powered off, and then the knife is withdrawn to complete the entire rolling process.

[0052] In summary, the present invention provides a flexible rolling tool and rolling method for thread bottom. Compared with the prior art, the present invention has the following beneficial effects:

[0053] Since the present invention adopts an electromagnet device to utilize electromagnetic force F 电磁 To drive the rolling wheel to roll the high-strength bolt, the specific steps are: first clamp the high-strength steel bolt 18 to be rolled on the three-jaw chuck 17 of the machine tool, tighten the tail with the tail tip 20, and use the automatic tool setting device 19 to set the tool. When the automatic tool setting device 19 is finished, the turret 21 drives the rolling tool to enter the first thread bottom; then the solenoid 11 is energized through the wire hole A14 and the wire hole B15. At this time, the fork frame 6 and the solenoid 11 form an electromagnet, and the cylindrical section of the fork frame 6 is equivalent to the iron core of the electromagnet. The electromagnet outputs an electromagnetic force F 电磁 , pressure sensor 16 shows F 电磁 Size, F 电磁 The high-strength steel bolt 18 is attracted. Since the high-strength steel bolt 18 to be processed is fixed on the three-jaw chuck 17, the rolling tool slides to the bottom of the thread through the slide groove 901 on the housing 9. By changing the input current I, F 电磁 and the required rolling force F 滚 is equal to the magnitude of , and the rolling current I0 at this time is obtained; during the rolling process, the magnitude of the rolling current I0 is kept unchanged, and the turret 21 moves axially along the high-strength steel bolt 18 to realize the rolling of the thread root. After the rolling is completed, the solenoid 11 is powered off, and then the tool is retracted, and the entire rolling process is completed, 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: It 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 to the inner shell (10) by screws, and the outer shell (9) is slidably connected to the inner shell (10); The rolling cutter head comprises a gasket (1), a rolling wheel (2), two bearings (3), a rolling mandrel (4), a pressure plate (5) and a fork frame (6); the fork frame (6) is an inverted T-shaped structure as a whole, and the upper end is a U-shaped structure, and 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 wheel (2) is mounted on the rolling mandrel (4); a gasket (1) is arranged between the right side of the rolling wheel (2) and the bearing (3); the pressure plate (5) is in contact with the bearing (3) and is connected to the fork frame (6) through screws; two connecting bolts (8) are symmetrically distributed on the left and right sides of the fork frame (6), and the rolling cutter head is connected to the electromagnet device through the two connecting bolts (8); two flexible springs (7) are respectively mounted on the connecting bolts (8); and the two bearings (3) are respectively embedded in the openings of the fork frame (6); The electromagnet device comprises a solenoid (11) and a main shaft (12); the main shaft (12) is in a T-shaped structure; the solenoid (11) is wound around the T-shaped lower end structure of the main shaft (12); and a pressure sensor (16) is arranged on the main shaft (12); The inner shell (10) is a cylindrical structure, and the two sliders (1001) are symmetrically distributed on the outer side of the cylindrical structure, and the inner shell (10) is mounted on the outer side of the solenoid (11); the outer shell (9) is a square structure, and the upper and lower sides of the outer shell (9) are transparent, and two symmetrically distributed slide grooves (901) are arranged inside the outer shell (9), and the two slide grooves (901) are symmetrically distributed and contact the turret (21), and are mounted on the outer side of the inner shell (10); the slide groove (901) is arranged on the inner side of the outer shell (9), and the slider (1001) is arranged on the outer side of the inner shell (10), and the slider (1001) slides up and down along the slide groove (901); The T-shaped cylindrical end of the main shaft (12) is provided with a wire hole B (15), and the lower end of the inner shell (10) is provided with a wire hole A (14); the solenoid (11) is connected to a power supply wire through the wire hole A (14) and the wire hole B (15).

2. The flexible rolling tool according to claim 1, characterized in that: The length of the solenoid (11) is equal to the length of the cylindrical end of the main shaft (12).

3. The flexible rolling tool according to claim 1, characterized in that: The materials of the gasket (1), the rolling wheel (2), the rolling mandrel (4), the pressing plate (5) and the fork frame (6) contained in the cutter head are non-magnetic conductive materials.

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

5. The flexible rolling tool according to claim 1, characterized in that: The main shaft (12) and the inner shell (10) are connected via a tail screw (13).

6. The flexible rolling tool according to claim 1, characterized in that: The amount by which the flexible spring (7) can be compressed is greater than the gap value between the pressure sensor (16) and the fork frame (6).

7. A flexible rolling method for thread root, characterized in that: Methods include: Step 1: Clamp the high-strength steel bolt (18) to be processed on the three-jaw chuck (17) of the machine tool, tighten the tail of the high-strength steel bolt (18) by the tail tip (20), and use the automatic tool setting device (19) to set the tool. When 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: Power the solenoid (11) through the wire hole A (14) and the wire hole B (15). At this time, the fork frame (6) and the solenoid (11) form an electromagnet, and the pressure sensor (16) displays F. 电磁 The rolling tool slides to the bottom of the thread through the slide groove (901) on the housing (9), and the input current I is changed to make F 电磁 With the preset rolling pressure F 滚 The magnitudes of are equal, and the rolling current I0 at this time is obtained; Step 3: During the rolling process, the rolling current I0 is kept constant to achieve a constant rolling force; the turret (21) moves axially along the high-strength steel bolt (18) to achieve rolling of the thread bottom; Step 4: After the rolling is completed, the solenoid (11) is powered off, and then the knife is withdrawn to complete the entire rolling process.

8. The flexible rolling method according to claim 7, characterized in that: Preset rolling force F 滚 The range is the size of the rolling force used in the project, and the value is 0-600N.

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