CN103898298A - Metal wire reinforcing device and method - Google Patents

Abstract

The invention discloses a metal wire strengthening device and a method thereof. The device includes a clamp for clamping the metal wire, a stretching servo motor for stretching the metal wire, and a torsion servo for twisting the metal wire. The motor, the stretching servo motor applies tension to the metal wire through the first transmission device or performs stretching and cold hardening, and the torsion servo motor performs torsional cold hardening on the metal wire through the second transmission device. The invention not only has the function of conventional torsional cold work hardening, but also can complete the torsional cold work hardening of the whole elongated metal wire at one time, and can also complete stretching cold work hardening alone or at the same time, effectively improving its strength and high working efficiency , and ensure that the mechanical properties of the metal wire after strengthening have a very good consistency and do not damage the metal wire; in addition, the device adopts a horizontal arrangement, the clamp can move in a wide range, and the restriction on the length of the wire is small, which can be used for most projects. The metal wire is directly hardened by cold work.

Description

Metal wire strengthening device and method thereof

technical field

The invention relates to the field of metal material processing, in particular to a metal wire strengthening device and a method thereof.

Background technique

Metal is the most widely used material in real life, and has penetrated into almost every corner of life. The use technology of metal plays a decisive role in the development of human beings. Since the industrial revolution, people have used various methods to improve the strength of metals, such as heat treatment, alloying, microstructure, cold work hardening, surface treatment, etc. Among them, cold work hardening is currently a cost that can significantly improve the strength of metal materials low-cost and widely used method. Cold work hardening refers to the strong plastic deformation of some metals processed at room temperature or below the crystallization temperature, which causes lattice distortion, distortion grains produce shear, slip, and grains are elongated. By changing the internal structure of the metal Thereby changing the strength of the metal, this method can significantly increase the strength of the metal, but at the same time reduce its plasticity and impact toughness.

Simple tensile hardening will make the diameter of the metal thinner during the stretching process, and the plastic deformation of the material is not sufficient, which affects the strengthening effect, and what is more, it will cause the metal to neck and cause the initial damage of the material. Torsional cold work hardening can make the material more fully strengthened, but torsional cold work hardening requires the length of the metal material to be shorter and the coaxiality is better, and the metal wires are relatively slender, and the axis is irregular when there is no external force Therefore, conventional torsional cold work hardening methods cannot be used in the prior art to strengthen it.

Therefore, it is necessary to provide a new technical solution to solve the above problems.

Contents of the invention

Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides a strengthening device suitable for elongated metal wires and a method thereof.

Technical solution: In order to achieve the above purpose, a metal wire strengthening device of the present invention includes a clamp for clamping the metal wire, a stretching servo motor for stretching the metal wire, and a tool for twisting the metal wire. A torsion servo motor, the stretching servo motor applies tension or stretches and cold-works the metal wire through the first transmission device, and the torsional servo motor performs torsional cold-work hardening on the metal wire through the second transmission device.

The first transmission device includes a first transmission belt, a first transmission wheel connected with the first transmission belt, and a leading screw. The first beam is installed on the leading screw, and one end of the leading screw passes through the first transmission wheel. The other end of the lead screw is located on the lead screw support; the second transmission device includes a reduction gear box, a second transmission belt and a second transmission wheel connected with the second transmission belt.

There are two first transmission pulleys, and the two first transmission pulleys are simultaneously connected with the stretching servo motor through the first transmission belt. The rotation of the servo motor drives the two first transmission pulleys to rotate at the same time, thereby driving the two screw rods to rotate synchronously, thereby ensuring that the first crossbeam advances or retreats on the screw rods.

The clamp includes a first wedge-shaped clamp and a second wedge-shaped clamp for respectively clamping two ends of the metal wire, the first wedge-shaped clamp is installed on the first beam, the second wedge-shaped clamp is installed on the second beam, and the second wedge-shaped clamp The fixture follows the action of the second transmission wheel.

The first wedge-shaped clamp and the second wedge-shaped clamp are respectively provided with a force sensor and an angle sensor, and a displacement sensor is provided on the first beam, and the stretching servo motor, torsion servo motor, force sensor, angle sensor and displacement sensor pass The wires are connected to the control system. A motion control card is connected between the wire and the control system. The control system is composed of computer, control software and control hardware. The stretching servo motor and the torsion servo motor are respectively installed on the bracket, and the first crossbeam sliding track for supporting and guiding is installed on the bracket.

In addition, an outer cover is also included, and the outer cover covers the stretching servo motor, the torsion servo motor, the lead screw, the first wedge-shaped clamp, and the second wedge-shaped clamp.

The present invention also discloses a torsional strengthening method based on the above-mentioned metal wire strengthening device, which includes the following principles and steps:

Torsional cold work hardening can maximize the strain strengthening ability of the material, that is, the metal material can be fully strengthened. When a metal material (especially a plastic metal material) is subjected to torsion, once the shear stress exceeds its shear yield limit, the material will undergo plastic deformation. After unloading, the strength of the material will increase, and its yield limit The improvement is particularly obvious.

For slender metal wires, the torsional strengthening method provided by the present invention is as follows:

1) According to the strengthening degree required by the metal material, input the diameter d of the metal wire, the slope critical value k of the tensile stress-strain curve at yield, and the strengthening target parameter (torsion angle θ _p per unit length) into the control system, and then according to the metal The length of the wire adjusts the distance between the first wedge-shaped clamp and the second wedge-shaped clamp, and the two ends of the metal wire are reliably clamped in the first wedge-shaped clamp and the second wedge-shaped clamp;

2) Start the stretching servo motor to drive the screw to move so that the metal wire bears a certain tension. The tension is transmitted to the control system through the force sensor. The control system draws the stress-strain curve according to the collected force and displacement data, and calculates the stress in real time. The slope k' of the strain curve, k'=(σ _i+1 -σ _i )/(ε _i+1 -ε _i ), the schematic diagram of the curve is shown in Figures 1 and 2. There are two situations of discontinuous yielding (obvious yielding, as shown in Figure 1) and continuous yielding (as shown in Figure 2) in the yield of metals, but the two have common features: when the metal wire enters the yield stage, the force-displacement curve and The slope of the stress-strain curve will be significantly smaller. Continuously apply tensile load to the metal wire. When the slope of the real-time stress-strain curve k'<k, the control system determines that the metal wire has yielded, and the control system issues an instruction to stop the stretching servo motor. At this time, the metal wire is completely straightened , to achieve good coaxiality. At the same time, the displacement sensor transmits the displacement data at this time (that is, the length L of the metal wire after removing the clamping part) to the control system.

3) Start the torsion servo motor and start to apply torque to the metal wire. When the torsion angle θ _p per unit length set by the control system is reached (θ _p = θ/L, θ is the torsion angle measured by the angle sensor), the torsion servo motor stops Afterwards, the control system gives an instruction to reverse the rotation of the servo motor, so that the second wedge-shaped clamp slowly reverses to remove the torque on the metal wire, and unload the metal wire when the torque on the metal wire is completely removed.

In the step 3), when the hardened metal wire is removed, the parts clamped by the clamps at both ends are not fully hardened, and the parts clamped by the clamps can be removed by cutting.

Beneficial effects: Compared with the prior art, a metal wire strengthening device and its method of the present invention have the following advantages:

(1) The torsional cold work hardening of the entire slender metal wire can be completed at one time, effectively improving its strength, high work efficiency, and ensuring that the mechanical properties of the metal wire after strengthening are very consistent without damaging the metal wire;

(2) In addition to the torsional cold work hardening of metal wires, it is also possible to carry out conventional tensile cold work hardening on metal materials, and can also realize the functions of stretching and torsional cold work hardening at the same time;

(3) The device adopts a horizontal arrangement, the fixture can be moved in a large range, and the restriction on the length of the wire is small, and most metal wires can be directly cold-hardened.

Description of drawings

Figure 1 is a stress-strain curve diagram of a plastic material with an obvious yield stage;

Figure 2 is a stress-strain curve diagram of a plastic material without an obvious yield stage;

Figure 3 shows the torsion strengthening of Q235 steel wire rods in different degrees (relative torsion angles on different unit lengths, that is, different

Curves of yield limit and strength limit after torsion angle per unit length);

Fig. 4 is the top view schematic diagram of device among the present invention;

Fig. 5 is the A-A sectional schematic diagram of Fig. 4;

Fig. 6 is a schematic perspective view of the three-dimensional structure of the device in the present invention.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

As shown in Figures 4 to 6, a metal wire strengthening device of the present invention includes a clamp for clamping the metal wire, a stretching servo motor 2 for stretching the metal wire, and a tensioning servo motor 2 for twisting the metal wire. The torsion servo motor 12, the stretching servo motor 2 realizes the distance adjustment between the first crossbeam 4 and the second crossbeam 10 through the first transmission device, and applies tension to the metal wire or performs stretching and cold hardening, the twist The servo motor 12 performs torsional cold work hardening on the metal wire through the second transmission device.

In this embodiment, the first transmission device includes a first transmission belt 3, a first transmission wheel 16 connected with the first transmission belt 3, and a lead screw 5, the first beam 4 is installed on the lead screw 5, and one end of the lead screw 5 It is connected with the first transmission wheel 16 by a key, and the other end of the leading screw 5 is located on the leading screw support 7; Transmission pulley 17; There are two first transmission pulleys 16, and the two first transmission pulleys 16 are connected with the stretching servo motor 2 through the first transmission belt 3 at the same time, and there are two leading screw 5, and each leading screw 5 is respectively Connected with a first transmission pulley 16, the stretching servo motor 2 rotates and simultaneously drives two first transmission pulleys 16 to rotate, thereby driving the two screw mandrels 5 to rotate synchronously, thereby ensuring that the first crossbeam advances or retreats on the lead screw 5. The clamps include a first wedge clamp 14 and a second wedge clamp 18 for respectively clamping the two ends of the metal wire, the first wedge clamp 14 is installed on the first beam 4, the second wedge clamp 18 is installed on the second beam 10, and The second wedge-shaped clamp 18 follows the action of the second transmission wheel 17 . Force sensor 15 and angle sensor 9 are respectively arranged on the first wedge-shaped clamp 14 and the second wedge-shaped clamp 18, and displacement sensor 23 is provided on the first crossbeam 4, and force sensor 15, angle sensor 9 and displacement sensor 23 communicate with control through wire 19 respectively. System 21 is connected. The stretching servo motor 2 and the torsion servo motor 12 are respectively firmly fixed on the support 1, and the support 1 is fixed on the flat ground, and the support 1 is provided with a first crossbeam sliding track for supporting and guiding. In addition, an outer cover 22 is also included, and the outer cover 22 covers the stretching servo motor 2 , the twisting servo motor 12 , the lead screw 5 , the first wedge-shaped clamp 14 , and the second wedge-shaped clamp 18 .

A method based on the above-mentioned metal wire strengthening device, comprising the following steps:

First, adjust the position of the fixture, and install the metal wire sample on the sample machine.

The steps for adjusting the distance between the two clamps are: start the stretching servo motor 2, drive the first transmission wheel 16 to rotate through the first transmission belt 3, and the first transmission wheel 16 is connected with the lead screw 5 by a key, so the first transmission wheel 16 The rotation of the lead screw 5 is equivalent to the transmission of the lead screw 5. The rotation of the lead screw 5 drives the first beam 4 to move back and forth in the horizontal direction, thereby adjusting the distance between the two fixtures. When the distance between the two fixtures matches the length of the metal wire Install the metal wire on the jig. Afterwards, it is torsionally or stretched cold hardened. Remember to cover the outer cover 22 after the above steps are completed, so as to avoid accidents such as sample breakage during the strengthening process.

According to the strengthening degree requirements of the metal material, the diameter d of the metal wire, the slope critical value k of the tensile stress-strain curve at yield, and the strengthening target parameter (torsion angle θ _p per unit length) are input into the control system, and then according to the metal wire The distance between the first wedge-shaped clamp 14 and the second wedge-shaped clamp 18 is adjusted in length, and the two ends of the metal wire are reliably clamped in the first wedge-shaped clamp 14 and the second wedge-shaped clamp 18; the stretching servo motor 2 is started to drive the wire The movement of the bar 5 causes the metal wire to bear a certain tension. In order to ensure that the metal wire is in a completely straightened state and does not cause damage to the metal wire (it can meet the requirements in the yielding stage), the magnitude of the tension must be strictly controlled. The tension generated when the lead screw 5 moves is transmitted to the control system 21 through the force sensor 15, and the control system 21 draws a stress-strain curve according to the input data, and calculates the slope k' of the stress-strain curve in real time, k'=(σ _{i+ 1} -σ _i )/(ε _i+1 -ε _i ), the curves are shown in Figures 1 and 2. When the metal wire enters the yield stage, the slopes of the force-displacement curve and the stress-strain curve will be significantly smaller (as shown in Figure 1 and Figure 2). The tensile load is continuously applied to the metal wire. When the slope of the real-time stress-strain curve k'<k, the control system 21 determines that the metal wire yields, and the control system 21 issues an instruction to stop the stretching servo motor 2. At this time, the metal wire is Fully straightened for good coaxiality. At the same time, the displacement sensor 23 transmits the displacement data at this time (that is, the length L of the metal wire after the clamping part is removed) to the control system 21 .

After the metal wire is completely straightened, start the twisting servo motor 12, thereby driving the second wedge-shaped clamp 18 to rotate, and start to apply torque to the metal wire. When the torsion angle θ _p per unit length set by the control system 21 is reached (θ _p = θ/L , θ is the twist angle measured by the angle sensor), after the twist servo motor 12 stops rotating. At this time, the torsion cold work hardening is completed, and the control system 21 controls the torsion servo motor 12 to slowly reverse, so that the second wedge-shaped clamp 18 slowly reverses to remove the torque on the metal wire. When the torque on the metal wire is completely released Remove the metal wire after removal.

After removing the hardened metal wire, the clamping parts at both ends of the fixture are not fully hardened. If the engineering application does not require high hardness of the end surface of the wire, it can be used directly without any treatment. If the engineering application requires that the mechanical properties of the metal wire are completely consistent , the part clamped by the fixture can be removed by cutting or other means.

The working process of stretching and cold hardening is: the stretching servo motor 2 is connected with the first transmission wheel 16 through the first transmission belt 3, and after the stretching servo motor 2 is started, the first transmission wheel 16 is driven to rotate by the first transmission belt 3 , the first transmission wheel 16 is assembled with the leading screw 5 with a key, so the rotation of the first transmission wheel is equivalent to the rotation of the leading screw 5. When the leading screw 5 rotates, the first beam 4 moves on the leading screw 5, and the first crossbeam 4 moves on the leading screw 5. A crossbeam 4 mainly supports the first crossbeam sliding track 6, which can ensure that the lead screw 5 is less stressed and will not be greatly deformed. It can also be transmitted to the first crossbeam sliding track through the first crossbeam 4 when it is subjected to torque. 6, ensure that the lead screw 5 will not be deformed by the torque. The first beam 4 can move back and forth on the leading screw 6, so that the distance between the two clamps can be adjusted according to the length of the metal wire. After the metal wire is installed, the movement of the first beam 4 provides the required force for stretching. The process control system 21 controls the magnitude of the pulling force in real time.

而小于

The tensile force required for strengthening is determined according to the degree of strengthening. If the diameter of the metal wire is d, the yield limit is σ _s , and the tensile strength limit is σ _b , then the minimum value of the force should be greater than

and less than

When the pulling force reaches the target value (and the pulling force value must be within the aforementioned range), the control system 21 gives an instruction to first stop the stretching servo motor 2, and then reverse the stretching servo motor 2 to remove the metal wire When the tensile force on the metal wire is completely removed, the metal wire can be removed, and the stretching and cold hardening end. In addition, since the parts clamped by the clamps at both ends of the metal wire are not hardened, the parts clamped by the clamps can be removed by cutting if necessary.

The working process of torsional cold work hardening is as mentioned above and will not be repeated.

After being processed by the device and method of the present invention, the strength of each section of the metal wire has a certain degree of improvement compared with that before torsion strengthening. Torsional cold work strengthening, the change curves of the yield limit and strength limit of the steel under different degrees of torsional strengthening (different torsion angles per unit length) are obtained as shown in Figure 3; the two dotted lines in the figure are Q235 round steel wires The tensile yield limit σ _s (275MPa) and the tensile strength limit σ _b (440MPa) without torsion strengthening, the two solid lines marked as σ _τs and σ _τb are the tensile strength of the sample under different torsion angles per unit length, respectively. The tensile yield strength and tensile strength limit; it can be seen from the figure that with the increase of the torsion angle per unit length, the strengthening degree increases continuously, and the tensile yield limit and tensile strength limit of the specimen continue to increase, that is, the strength of the specimen can be effectively improved.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications are also possible. It should be regarded as the protection scope of the present invention.

Claims (9)

1. A metal wire strengthening device, characterized in that it includes a clamp for clamping the metal wire, a stretching servo motor (2) for stretching the metal wire, and a torsion servo for twisting the metal wire The motor (12), the stretching servo motor (2) applies tension to the metal wire through the first transmission device or performs stretching and cold hardening, and the twisting servo motor (12) twists the metal wire through the second transmission device Hardening by cold work. 2. The metal wire reinforcement device according to claim 1, characterized in that: the first transmission device comprises a first transmission belt (3), a first transmission wheel (16) connected to the first transmission belt (3) and the lead screw (5), the first beam (4) is installed on the lead screw (5), one end of the lead screw (5) is connected with the first transmission wheel (16) by a key, the lead screw (5) The other end of the screw is located on the screw support (7); the second transmission device includes a reduction gear box (13), a second transmission belt (11) and a second transmission wheel ( 17). 3. The metal wire strengthening device according to claim 2, characterized in that there are two first transmission pulleys (16), and the two first transmission pulleys (16) are simultaneously connected with the first transmission belt (3) The stretching servo motor (2) is connected, and the screw (5) has two, and each screw (5) is respectively connected with a first transmission pulley (16), and the stretching servo motor (2) rotates to drive the two pulleys simultaneously. The first transmission pulley (16) rotates, thereby driving the two screw rods (5) to rotate synchronously, and then drives the first beam to move forward or backward on the screw rod (5). 4. The metal wire strengthening device according to claim 3, characterized in that: the clamp includes a first wedge-shaped clamp (14) and a second wedge-shaped clamp (18) for respectively clamping the two ends of the metal wire, the first wedge-shaped The clamp (14) is installed on the first beam (4), the second wedge-shaped clamp (18) is installed on the second beam (10), and the second wedge-shaped clamp (18) follows the action of the second transmission wheel (17). 5. The metal wire strengthening device according to claim 4, characterized in that: the first wedge-shaped clamp (14) and the second wedge-shaped clamp (18) are respectively provided with a force sensor (15) and an angle sensor (9), A displacement sensor (23) is arranged on the first beam (4), and the force sensor (15), angle sensor (9) and displacement sensor (23) are respectively connected to the control system (21) through wires (19), and the wires ( 19) A motion control card (20) is connected with the control system (21). 6. The metal wire strengthening device according to claim 4, characterized in that: the stretching servo motor (2) and the torsion servo motor (12) are installed on the bracket (1) respectively, and the bracket (1) is installed with The first crossbeam sliding track (6) that supports and guides. 7. The metal wire strengthening device according to claim 4, characterized in that it also includes a cover (22), the cover (22) will stretch the servo motor (2), twist the servo motor (12), the lead screw ( 5), the first wedge-shaped clamp (14), and the second wedge-shaped clamp (18) cover. 8. A method based on the metal wire strengthening device according to any one of claims 1 to 7, characterized in that it comprises the following steps: 1) According to the strengthening degree required by the metal material, input the diameter of the metal wire, the slope critical value k of the tensile stress-strain curve at yield, and the strengthening target parameters into the control system (21), and then adjust the first step according to the length of the metal wire. The distance between the wedge-shaped clamp (14) and the second wedge-shaped clamp (18), and the two ends of the metal wire are reliably clamped in the first wedge-shaped clamp (14) and the second wedge-shaped clamp (18); 2) Start the stretching servo motor (2) to drive the screw (5) to move so that the metal wire bears a certain tension, which is transmitted to the control system (21) through the force sensor (15), and the control system (21) according to the collected Draw the stress-strain curve based on the force and displacement data, and calculate the slope k' of the stress-strain curve in real time. When the metal wire enters the yield stage, the slopes of the force-displacement curve and the stress-strain curve will be significantly smaller; for metal wire The tensile load is continuously applied, and when the slope of the real-time stress-strain curve k'<k, the control system (21) determines that the metal wire has yielded, and the control system (21) issues an instruction to stop the tension servo motor (2). The metal wire is completely straightened to achieve good coaxiality; at the same time, the displacement sensor (23) transmits the displacement data at this time to the control system (21); 3) Start the torsion servo motor (12) and start to apply torque to the metal wire. When the torsion angle per unit length set by the control system (21) is reached, the torsion servo motor (12) stops rotating; then the control system (21) gives The command reverses the twisting servo motor (12), so that the second wedge-shaped clamp (18) slowly reverses to remove the torque on the metal wire, and unload the metal wire when the torque on the metal wire is completely removed. 9. The method according to claim 8, characterized in that: in the step 3), the hardened metal wire is removed, and the clamping parts at both ends of the clamp are not fully hardened, and the clamp can be clamped by cutting. Tight parts are removed.

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