GB2589023A

GB2589023A - Magnetic drive-type device for strengthening inner surface of tapered hole

Info

Publication number: GB2589023A
Application number: GB2019820.6A
Authority: GB
Inventors: Li Fuzhu; Sun Shengnan; Guo Yuqin; Zhu Yiqing; Yu Weijie; Chen Weiguo; Wang Yun; Jiang Pengyun; Li Ruitao
Original assignee: Jiangsu University
Current assignee: Jiangsu University
Priority date: 2019-04-28
Filing date: 2020-06-28
Publication date: 2021-05-19
Anticipated expiration: 2040-06-28
Also published as: GB2589023B; GB202019820D0; CN110055397A; WO2020221377A2; WO2020221377A3; CN110055397B

Abstract

A magnetic drive-type device for strengthening the inner surface of a tapered hole, said device belonging to the field of spare-parts surface processing. The device is provided with a cylinder (1); a workpiece (2) is vertically disposed at the bottom of the inside of a cylinder (1); the workpiece (20) is provided with a tapered hole (22) the large end of which faces directly upward; a top cover (4) is arranged directly above the workpiece (2); the center of the top cover (4) is provided with a top cover through-hole (19) that is in communication with the tapered hole (22); a piston (5) is arranged in the top cover through-hole; (19) the piston (5) is coaxially and fixedly connected to the lower end of a connecting rod (8); and the upper end of the connecting rod (8) extends upward and out of the top cover (4) and is fixedly connected to a sliding block (9); the sliding block (9) is slidably connected to a vertical guide rail (10); the sliding block (9) is also fixedly connected to one end of a transmission rod (11); the other end of the transmission rod (11)is fixedly connected to the edge of a disc 17) horizontally arranged at the center axis; the disc (17) is coaxially and fixedly connected to one end of a commutator segment (16); the other end of the commutator segment (16) is fixedly connected to a coil (13); the coil (13) is horizontally placed between a pair of magnets (12); the commutator segment (16) is in contact with a brush (14); the brush (14); is connected to a power supply (15) by means of a wire; and magnetically-driven volume alternation causes the pressure of the liquid in the volume to change, which results in cavitation and strengthening, and thus a good strengthening effect.

Description

MAGNETIC DRIVE-TYPE APPARATUS FOR STRENGTHENING INNER

SURFACE OF TAPERED HOLE

Technical Field

[0001] The present invention relates to the field of part surface treatment, and in particular, to an apparatus for strengthening an inner surface of a tapered hole.

Background

[0002] At present, the requirements on precision of mechanical equipment and mechanical products get increasingly higher. Tapered holes have high positioning precision and are widely used in various mechanical parts, but the machining of the tapered holes is relatively difficult. Since the fatigue performance of the inner surface of a tapered hole has a great influence on the performance of a mechanical part, the quality of the inner surface of the tapered hole is required to be high. The inner surface of the tapered hole can be strengthened to improve its mechanical performance, thereby prolonging the fatigue life of the part.

[0003] Currently, mechanical shot peening and cold extrusion are mostly adopted for strengthening the inner surface of a hole. The mechanical shot peening is to strike the inner surface of a hole with shot and generate residual stresses on the inner surface of the hole, thereby strengthening the inner surface of the hole and prolonging the service life of the hole. However, holes with small diameters cannot be machined by mechanical shot peening, and the shot peening has a non-uniform strengthening effect. The cold extrusion strengthening is to forcibly squeeze a mandrel through a hole to be strengthened, wherein the diameter of the mandrel is slightly larger than that of the hole, so that residual stresses are generated by extrusion on the inner surface of the hole. The cold extrusion strengthening process also has the problems that the residual stresses are non-uniformly distributed, it is impossible to machine micro-holes, let alone tapered holes, and so on.

[0004] The Chinese Patent Publication No. CN103589854A discloses an electromagnetic strengthening method, wherein a strengthening coil is arranged on a workpiece and the workpiece is placed in a magnetic field, a rapidly changing pulse current is introduced into the strengthening coil to generate an induced eddy current in the workpiece, and a pulse electromagnetic force is generated under the combined effects of the induced eddy current and the magnetic field, so that residual stresses for the purpose of strengthening are generated on the inner surface of a hole. However, this strengthening method cannot work on holes with small diameters and the precision thereof is not high.

Summary

[0005] An objective of the present invention is to provide a magnetic drive-type apparatus for strengthening an inner surface of a tapered hole to eliminate the deficiencies in the prior art, thereby solving the problems of the conventional strengthening methods that the residual stresses are non-uniformly distributed, it is impossible to machine tapered holes and micro-holes, and so on.

[0006] To achieve the objective of the present invention, the present invention adopts the following technical solution. The present invention has a cylinder body, wherein a workpiece is vertically arranged at a bottom of an inside of the cylinder body, and the workpiece is provided with a tapered hole with a large end facing directly upward; a top cover is arranged right above the workpiece, a top cover through-hole that is in communication with the tapered hole is provided at a center of the top cover, a piston is arranged in the top cover through-hole, a seal ring is mounted on a lower surface of the top cover, and when the lower surface of the top cover is in close contact with an upper surface of the workpiece, a part of the top cover through-hole located below the piston and the tapered hole form a closed chamber, and the closed chamber is filled with a liquid; the piston is coaxially and fixedly connected to a lower end of a connecting rod, an upper end of the connecting rod extends upward and out of the top cover and is fixedly connected to a slider, the slider is slidably connected to a vertical guide rail and is fixedly connected to one end of a drive rod, and the other end of the drive rod is fixedly connected to an edge of a disc with a central axis arranged horizontally; the disc is coaxially and fixedly connected to one end of commutator segments, the other end of each of the commutator segments is fixedly connected to a coil, the coil is horizontally arranged between a pair of magnets, each of the commutator segments is in contact with a brush, and the brush is connected to a power supply through a wire.

[0007] A clamping device for tightly pressing the top cover against the workpiece is arranged between the top cover and the cylinder body. The clamping device consists of a retractable hydraulic cylinder, a pressing plate, an oil tank, an oil pump, and a two-position four-way electromagnetic reversing valve, wherein a lower end of the retractable hydraulic cylinder is vertically and fixedly connected to an upper end of the cylinder body and an upper end of the retractable hydraulic cylinder is connected to the horizontal pressing plate, the pressing plate is arranged above the top cover, the retractable hydraulic cylinder is connected to the oil tank through a pipe, and the oil pump and the two-position four-way electromagnetic reversing valve are arranged on the pipe between the oil tank and the retractable hydraulic cylinder.

[0008] Through the above technical solution, the present invention achieves the following beneficial effects: 1. In the present invention, an alternating volume is produced through magnetic drive.

Specifically, the piston is driven by a magnetic force to produce an alternating closed volume and the liquid pressure in the volume changes accordingly, which leads to cavitation strengthening. When the volume is increased, the liquid pressure is lower than the saturated vapor pressure of the liquid, and cavitation bubbles are generated in the liquid. When the volume is reduced, the cavitation bubbles are squeezed and collapse, producing shock waves which cause residual stresses for the purpose of strengthening on the inner surface of the tapered hole. Therefore, the service life of the workpiece is prolonged, and the apparatus is simple and is convenient to operate.

[0009] 2. The present invention can be used to machine holes of other shapes, especially micro-holes, and sets no limitation on the size and shape of the holes.

[0010] 3. The present invention performs inner surface treatment of a tapered hole through cavitation, and there is no mechanical contact on the wall of the hole, so that the residual stresses are uniformly distributed, tapered holes with small diameters can be machined, the strengthening effect is good, the machining efficiency is high, and no pollution source is caused.

Brief Description of the Drawings

[0011] FIG. 1 is a schematic structural diagram of a magnetic drive-type apparatus for strengthening an inner surface of a tapered hole according to the present invention.

In FIG. I, 1: cylinder body; 2: workpiece; 3: seal ring; 4: top cover; 5: piston; 6: retractable hydraulic cylinder; 7: pressing plate; 8: connecting rod; 9: slider; 10: guide rail; 11: drive rod; 12: magnet; 13: coil; 14: brush; 15: power supply; 16: commutator segment; 17: disc; 18: air vent; 19: top cover through-hole; 20: water inlet; 21: two-position four-way electromagnetic reversing valve; 22: tapered hole; 23: oil pump; 24: water pump; 25: oil tank; 26: water outlet; 27: water storage tank.

Detailed Description of the Embodiments

[0012] As shown in FIG. 1, the present invention has a cylinder body 1, and a workpiece 2 is 20 vertically arranged at a bottom of an inside of the cylinder body 1. A groove is made in the bottom of the cylinder body 1, and a lower end of the workpiece 2 is placed in the groove, facilitating the positioning of the workpiece 2.

[0013] The workpiece 2 is provided with a tapered hole 22 with a large end facing directly upward, and the tapered hole 22 is filled with a liquid during the operation. A top cover 4 is arranged right above the workpiece 2, and a top cover through-hole 19 that is in communication with the tapered hole 22 is provided at the center of the top cover 4, wherein the two holes share the same central axis. An inner diameter of the top cover through-hole 19 is greater than that of the large end of the tapered hole 22. A piston 5 is arranged in the top cover through-hole 19. The piston 5 is in sealed connection to an inner wall of the top cover through-hole 19 and is capable of moving up and down along the inner wall of the top cover through-hole 19. A seal ring 3 is mounted on a lower surface of the top cover 4. When the lower surface of the top cover 4 is in close contact with an upper surface of the workpiece 2, a part of the top cover through-hole 19 located below the piston 5 and the tapered hole 22 form a closed chamber which is sealed by the top cover 4. The closed chamber is filled with a liquid. When the piston 5 moves up and down, the volume of the closed chamber changes and the liquid pressure in the volume changes accordingly, which leads to cavitation and enables surface strengthening on the tapered hole 22 in the workpiece 2.

[0014] The piston 5 is coaxially and fixedly connected to a lower end of a connecting rod 8. An upper end of the connecting rod 8 extends upward and out of the top cover 4, and is fixedly connected to a slider 9. The slider 9 is also slidably connected to a vertical guide rail 10, and the guide rail 10 is fixed. When the slider 9 moves up and down along the guide rail 10, the connecting rod 8 and the piston 5 are brought to move up and down in a reciprocating manner.

[0015] The slider 9 is also fixedly connected to one end of a drive rod 11, and the other end of the drive rod 11 is fixedly connected to an edge of a disc 17. The disc 17 has a central axis arranged horizontally, one side of the disc faces the other end of the drive rod 11, and the other end of the drive rod 11 is fixedly connected by a screw to the edge of this side of the disc. A gasket is arranged at the joint of the drive rod 11 and the disc 17, to reduce the friction between the disc 17 and the drive rod 11.

[0016] Four counterbores are made in the disc 17, and the disc 17 is fixedly connected to one end of commutator segments 16 through bolts, ensuring that the bolts do not protrude from the disc surface to hinder the movement of the drive rod 11 and the disc 17. The commutator segments 16 share the same central axis with the disc 17. Each of the commutator segments 16 is in contact with a brush 14, and the brush 14 is connected to a power supply 15 through a wire. The disc 17 is made of an insulating material, and the commutator segments 16 and the brush 14 are made of conducting materials. The other end of each of the commutator segments 16 is fixedly connected to a coil 13, and the coil 13 shares the same central axis with the commutator segments 16. The coil 13 is horizontally arranged between an N-pole and an S-pole of a pair of magnets 12.

[0017] When the power supply 15 is turned on, the coil 13 is electrified through the brush 14 and the commutator segments 16, and starts rotating in a magnetic field generated by the magnets 12. The commutator segments 16 enable the coil 13 to rotate continuously in one direction. The disc 17 is forced to rotate along with the coil 13 and the commutator segments 16, and the other end of the drive rod 11 moves in a circular path along with the disc 17. Constrained by the guide rail 10, one end of the drive rod 11 forces the slider 9 to move up and down in a reciprocating manner along the guide rail 10, thereby forming a crank-slider driving mechanism. The slider 9 drives the connecting rod 8 to move up and down, so that the volume of the closed chamber changes and the liquid pressure in the closed chamber changes accordingly, which leads to cavitation and enables surface strengthening on the tapered hole 22 in the workpiece 2.

[0018] An air vent 18 is provided on an upper end of the top cover 4, and the air vent 18 is in communication with a part of the top cover through-hole 19 located above the piston 5, so that the top cover through-hole 19 is open to the atmosphere, and air in the top cover through-hole 19 can be discharged out.

[0019] A clamping device for tightly pressing the top cover 4 against the workpiece 2 is arranged between the top cover 4 and the cylinder body 1, so that the top cover 4 can be closely and fixedly attached to the top of the workpiece 2. The clamping device consists of a retractable hydraulic cylinder 6, a pressing plate 7, an oil tank 25, an oil pump 23, and a two-position four-way electromagnetic reversing valve 21. A lower end of the retractable hydraulic cylinder 6 is vertically and fixedly connected to an upper end of the cylinder body 1, and an upper end of the retractable hydraulic cylinder 6 is connected to the horizontal pressing plate 7. The pressing plate 7 is arranged above the top cover 4. The retractable hydraulic cylinder 6 is connected to the oil tank 25 through a pipe, and the oil pump 23 and the two-position four-way electromagnetic reversing valve 21 are arranged on the pipe between the oil tank 25 and the retractable hydraulic cylinder 6. Four retractable hydraulic cylinders 6 are provided and are uniformly distributed along the circumference of the cylinder body 1.

[0020] A water inlet 20 is provided on an upper side of the cylinder body 1 and a water outlet 26 is provided on a lower side of the cylinder body 1, the water outlet 26 is connected to a water storage tank 27 through a pipe, and the water storage tank 27 is connected to the water inlet 20 through a pipe and a water pump 24.

[0021] During the operation of the present invention, the workpiece 2 is firstly placed in the cylinder body 1, the water outlet 26 is closed, the water pump 24 is turned on, and the water inlet is open, to feed the water in the water storage tank 27 into the cylinder body 1. When the water in the cylinder body 1 immerses the workpiece 2 and is close to the water inlet 20, the closed chamber is filled with the liquid, and then the water pump 24 is turned off and the water inlet 20 is closed. The top cover 4 is placed right above the workpiece 2. The oil pumps 23 are turned on, and the two-position four-way electromagnetic reversing valves 21 are adjusted to control the retractable hydraulic cylinders 6 to move downward, thereby pulling the pressing plates 7 downward to be tightly pressed against the top cover 4. After that, the power supply 15 is turned on to enable the piston 5 to move up and down in a reciprocating manner, resulting in volume changes in the closed chamber and leading to surface strengthening of the workpiece 2. When the machining of the workpiece 2 is finished, the power supply 15 is turned off, the electromagnetic reversing valves 21 are adjusted to enable the retractable hydraulic cylinders 6 to move upward and push away the pressing plates 7, and the top cover 4 is removed. Finally, the water outlet 26 is opened to discharge the water in the cylinder body 1, and the workpiece 2 is taken out.

Claims

Claims What is claimed is: I. A magnetic drive-type apparatus for strengthening an inner surface of a tapered hole, having a cylinder body (I), wherein a workpiece (2) is vertically arranged at a bottom of an inside of the cylinder body (1), and the workpiece (2) is provided with a tapered hole (22) with a large end facing directly upward, characterized in that a top cover (4) is arranged right above the workpiece (2), a top cover through-hole (19) that is in communication with the tapered hole (22) is provided at a center of the top cover (4), a piston (5) is arranged in the top cover through-hole (19), a seal ring (3) is mounted on a lower surface of the top cover (4), and when the lower surface of the top cover (4) is in close contact with an upper surface of the workpiece (2), a part of the top cover through-hole (19) located below the piston (5) and the tapered hole (22) form a closed chamber, and the closed chamber is filled with a liquid; the piston (5) is coaxially and fixedly connected to a lower end of a connecting rod (8), an upper end of the connecting rod (8) extends upward and out of the top cover (4) and is fixedly connected to a slider (9), the slider (9) is slidably connected to a vertical guide rail (10) and is fixedly connected to one end of a drive rod (11), and the other end of the drive rod (11) is fixedly connected to an edge of a disc (17) with a central axis arranged horizontally; the disc (17) is coaxially and fixedly connected to one end of commutator segments (16), the other end of each of the commutator segments (16) is fixedly connected to a coil (13), the coil (13) is horizontally arranged between a pair of magnets (12), each of the commutator segments (16) is in contact with a brush (14), and the brush (14) is connected to a power supply (15) through a wire.
2. The magnetic drive-type apparatus for strengthening the inner surface of the tapered hole according to claim 1, characterized in that a clamping device for tightly pressing the top cover (4) against the workpiece (2) is arranged between the top cover (4) and the cylinder body (I), and the clamping device consists of a retractable hydraulic cylinder (6), a pressing plate (7), an oil tank (25), an oil pump (23), and a two-position four-way electromagnetic reversing valve (21), wherein a lower end of the retractable hydraulic cylinder (6) is vertically and fixedly connected to an upper end of the cylinder body (1) and an upper end of the retractable hydraulic cylinder (6) is connected to the horizontal pressing plate (7), the pressing plate (7) is arranged above the top cover (4), the retractable hydraulic cylinder (6) is connected to the oil tank (25) through a pipe, and the oil pump (23) and the two-position four-way electromagnetic reversing valve (21) are arranged on the pipe between the oil tank (25) and the retractable hydraulic cylinder (6).
3. The magnetic drive-type apparatus for strengthening the inner surface of the tapered hole according to claim 2, characterized in that four retractable hydraulic cylinders (6) are provided and are uniformly distributed along a circumference of the cylinder body (1).
4. The magnetic drive-type apparatus for strengthening the inner surface of the tapered hole according to claim I, characterized in that a water inlet (20) is provided on an upper side of the cylinder body (1) and a water outlet (26) is provided on a lower side of the cylinder body (1), the water outlet (26) is connected to a water storage tank (27) through a pipe, and the water storage tank (27) is connected to the water inlet (20) through a water pump (24).
5. The magnetic drive-type apparatus for strengthening the inner surface of the tapered hole according to claim 1, characterized in that an air vent (18) is provided on an upper end of the top cover (4), and the air vent (18) is in communication with a part of the top cover through-hole (19) located above the piston (5) and is open to the atmosphere.
6. The magnetic drive-type apparatus for strengthening the inner surface of the tapered hole according to claim 1, characterized in that an inner diameter of the top cover through-hole (19) is greater than that of the large end of the tapered hole (22).