Twist processing method, twist processing program, and twist processing machine

Abstract

To perform twist processing which reduces load torque of twist deformation and is high in accuracy of phase positioning.SOLUTION: A twist processing method includes: a first synchronized rotation step (S1) of synchronously rotating two rotating shafts with both ends of a workpiece held by the two rotating shafts; a heating step (S2) of heating the workpiece via a heater while synchronously rotating the two rotating shafts; twist processing steps (S3, S4) of adding a twisting motion to the workpiece by setting a difference in rotational speeds of the two rotating shafts after the lapse of a prescribed heating time from the start of the heating in the heating step; a second synchronization rotation step (S6) of synchronously rotating the two rotating shafts after the end of the twist processing steps; a heating stopping step (S7) of stopping the heating by the heater during the execution of the second synchronization rotation step; and a releasing step (S8) of stopping the synchronization rotation of the two rotating shafts after stop of the heating by the heater.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a twist processing method for twisting a workpiece, a twist processing program for executing the method, and a twist processing machine. [Background technology]

[0002] Twisting is a plastic processing method for manufacturing machine parts, decorative objects, etc. by twisting a workpiece (material) such as a bar or plate on an axial line to deform it. For example, Patent Document 1 describes a method for manufacturing a crankshaft using twisting. Since crankshafts are difficult to stamp out when forging a material due to their complex shape, the manufacturing method in Patent Document 1 involves forming the material into a shape that can be stamped out, and then using twisting to change the phase of the processed area to produce the finished shape. Since twist processing utilizes plastic deformation, the workpiece is generally made of metal materials such as steel, and therefore requires a high twisting torque, making it necessary to use dedicated equipment equipped with a high-torque motor and a twisting die to prevent the workpiece from slipping. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 2998058 Summary of the Invention [Problem to be solved by the invention]

[0004] When twist processing is performed with a machine tool, the material is generally a metal material such as steel, but since the load torque of the torsional deformation is high, it may be difficult to perform plastic deformation of the torsion with the spindle motor torque of the machine tool. Furthermore, there are issues such as the difficulty of performing twist processing with good phase positioning accuracy due to the occurrence of slippage during chucking of the workpiece and the large return amount due to the release of elastic strain after deformation.

[0005] Therefore, an object of the present disclosure is to provide a twisting method, a twisting program, and a twisting machine that can reduce the load torque of torsional deformation and perform twisting with good phase positioning accuracy. [Means for solving the problem]

[0006] In order to achieve the above object, a first configuration of the present disclosure is a method for performing twist processing on a workpiece using two opposing rotation shafts, a workpiece heating device, and a control device that controls each of the rotation shafts and the heating device, comprising: A first synchronous rotation step of holding both ends of a workpiece by the two rotating shafts and synchronously rotating the two rotating shafts; a heating step of heating the workpiece by the heating device while rotating the two rotation shafts synchronously; a twist processing step in which a difference between the rotation speeds of the two rotating shafts is set after a predetermined heating time has elapsed since the start of heating in the heating step, thereby applying a twisting operation to the workpiece; a second synchronous rotation step of synchronously rotating the two rotating shafts after the twisting step is completed; a heating stopping step of stopping heating by the heating device during execution of the second synchronous rotation step; a release step of stopping the synchronous rotation of the two rotating shafts after the heating by the heating device is stopped; Run Along with, The twisting operation in the twist processing step is performed until a predetermined processing time has elapsed in which the rotation speed of each of the rotating shafts is set and a desired twist phase value is obtained by multiplying the rotation speed and the difference between the rotation speeds of the rotating shafts. It is characterized by: Another aspect of the first configuration of the present disclosure is a method for performing twist processing on a workpiece using two opposing rotation shafts, a workpiece heating device, and a control device that controls each of the rotation shafts and the heating device, comprising: A first synchronous rotation step of holding both ends of a workpiece by the two rotating shafts and synchronously rotating the two rotating shafts; a heating step of heating the workpiece by the heating device while rotating the two rotation shafts synchronously; a twist processing step in which a difference between the rotation speeds of the two rotating shafts is set after a predetermined heating time has elapsed since the start of heating in the heating step, thereby applying a twisting operation to the workpiece; a second synchronous rotation step of synchronously rotating the two rotating shafts after the twisting step is completed; a heating stopping step of stopping heating by the heating device during execution of the second synchronous rotation step; a release step of stopping the synchronous rotation of the two rotating shafts after the heating by the heating device is stopped; Run Along with, The twisting operation in the twist processing step is performed by setting the rotation speed of each of the rotating shafts and monitoring the phase difference between the rotating shafts until a desired twist phase value is obtained. It is characterized by: Another aspect of the first configuration of the present disclosure is characterized in that, in the above configuration, in the twist processing step, the stress-strain relationship in the elastic region of the workpiece is calculated based on the relationship between the load torque difference and phase difference of each of the rotating shafts immediately after the start of the twisting operation, and the amount of elastic strain recovery after the release step is estimated from the load torque difference of each of the rotating shafts at the end of the twisting operation, and compensating twist control is performed to compensate for the amount of elastic strain recovery. In order to achieve the above object, a second configuration of the present disclosure is a twist processing program which causes a control device of a twist processing machine having two opposing rotating shafts, a workpiece heating device, and a control device for controlling each of the rotating shafts and the heating device to execute a twist processing method described in any of the first configurations of the present disclosure. In order to achieve the above object, a third configuration of the present disclosure is a twisting machine including two opposing rotating shafts, a work heating device, and a control device that controls each of the rotating shafts and the heating device, a first synchronous rotation means for synchronously rotating the two rotary shafts while holding both ends of the workpiece; A heating means for heating the workpiece by the heating device while rotating the two rotary shafts synchronously; a twist processing means for applying a twisting motion to the workpiece by setting a difference between the rotation speeds of the two rotating shafts after a predetermined heating time has elapsed since the start of heating by the heating device; a second synchronous rotation means for synchronously rotating the two rotating shafts after the twisting process is performed; a heating stop means for stopping heating by the heating device while the second synchronous rotation means is being executed; a release means for stopping the synchronous rotation of the two rotating shafts after the heating by the heating device is stopped; Equipped with 、 The twisting operation in the twist processing means is performed until a predetermined processing time has elapsed in which the rotation speed of each of the rotating shafts is set and a desired twist phase value is obtained by multiplying the rotation speed and the difference between the rotation speeds of the rotating shafts. It is characterized by: Another aspect of the third configuration of the present disclosure is A twist processing machine including two opposing rotary shafts, a work heating device, and a control device for controlling each of the rotary shafts and the heating device, a first synchronous rotation means for synchronously rotating the two rotary shafts while holding both ends of the workpiece; A heating means for heating the workpiece by the heating device while rotating the two rotary shafts synchronously; a twist processing means for applying a twisting motion to the workpiece by setting a difference between the rotation speeds of the two rotating shafts after a predetermined heating time has elapsed since the start of heating by the heating device; a second synchronous rotation means for synchronously rotating the two rotating shafts after the twisting process is performed; a heating stop means for stopping heating by the heating device while the second synchronous rotation means is being executed; a release means for stopping the synchronous rotation of the two rotating shafts after the heating by the heating device is stopped; Equipped with 、 The twisting operation in the twist processing means is performed by setting the rotation speed of each of the rotating shafts and monitoring the phase difference between the rotating shafts until a desired twist phase value is obtained. It is characterized by: Effect of the Invention

[0007] According to the present disclosure, the entire circumference of the workpiece is softened by heating during rotation, i.e., the yield stress is reduced, and the load torque required for processing is reduced. Therefore, it is expected that chucking slippage will be suppressed and the return amount will be reduced by releasing the elastic strain, and twist processing with good phase positioning accuracy can be performed. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of twist processing on a lathe. [Diagram 2] 1 is a flowchart of a twisting method. [Diagram 3] FIG. 4 is an explanatory diagram showing the angular velocity of each spindle and heating (laser irradiation) over time. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 is a schematic diagram of a twist processing using a lathe M as a twist processing machine. Fig. 2 is a flowchart of a twist processing method. Fig. 3 is an explanatory diagram showing the time course of the twist processing. The lathe M is capable of holding both ends of a workpiece 4 between a main spindle 1 and an opposing spindle 2 that is arranged coaxially with the main spindle 1. The workpiece 4 is a bar material with a circular cross section. The lathe M also includes a laser unit 3 as a heating device for the workpiece 4. The control device 10 of the lathe M controls both spindles 1, 2 and the laser unit 3 according to a twist processing program stored in advance in the storage unit to execute the twist processing method of Fig. 2. That is, the control device 10, together with both spindles 1, 2, constitutes the first and second synchronous rotation means, twist processing means, and release means of the present disclosure, and together with the laser unit 3, constitutes the heating means and heating stop means of the present disclosure.

[0010] In FIG. 2, first, in S1, the main spindle 1 and the counter spindle 2 are rotated synchronously in the direction of the arrow so as to have an angular velocity ω1 preset in the storage unit (t1 in FIG. 3: first synchronous rotation step). Next, in S2, while maintaining the synchronous rotation, the laser unit 3 irradiates the workpiece 4 with a laser (heating step). This irradiation heats and softens the heating range 5 of the workpiece 4. The output of the laser unit 3, the heating position coordinates of the workpiece 4, and the heating time during the synchronous rotation (t2 to t3 in FIG. 3) are set in the control device 10. Here, by rotating both spindles 1, 2 synchronously and then applying heat, the entire circumference of the workpiece 4 can be reliably heated even if the heating point is limited in area.

[0011] Next, after the heating time has elapsed, in S3, while maintaining the laser irradiation to prevent the workpiece 4 from cooling, a twisting operation is performed by changing the angular velocity of one of the spindles to ω2 without stopping the rotation of both spindles 1 and 2 (t3: twist processing step in Figure 3). At the same time, in S3, the load torque difference and phase difference of both spindles 1 and 2 immediately after the start of the twisting operation are obtained. This makes it possible to obtain the stress-strain relationship in the elastic region of the workpiece 4 during twist processing. The twisting operation is performed in S4 until a predetermined processing time t elapses (t3 to t4 in FIG. 3) at which θ, which is a target twist phase value (desired twist phase value), is obtained. θ=(ω1-ω2)×t For example, when the workpiece 4 is to be twisted to the left, the angular velocity of the counter spindle 2 is changed to ω2 so that ω1<ω2 holds. When the workpiece 4 is to be twisted to the right, the angular velocity is changed to ω1>ω2. However, here, regardless of the machining time t, the phase difference between both spindles 1 and 2 may be monitored and twisting operations may be added until the target twisting phase value θ is obtained.

[0012] If there is a difference in the load torque between the spindles 1 and 2 when the target torsional phase value θ is reached in S4, the release of elastic strain may cause a return when the synchronization control is released, which may deteriorate the phase accuracy. Therefore, the control device 10 monitors the load torque difference between the spindles 1 and 2 from the stress-strain relationship acquired in S3 at the time when the target torsional phase value θ is reached in S4 after the machining time t has elapsed. If there is a load torque difference, the amount of return of the elastic strain after the end of this control can be estimated based on the stress-strain relationship. Therefore, in S5, the control device 10 estimates the elastic strain from the load torque difference between the two spindles 1 and 2, and performs compensatory torsion control to compensate for the return amount of the elastic strain. This compensatory torsion control is performed by extending the processing time t of the twisting operation or by adding an additional twisting operation. Note that if there is no load torque difference when the target torsion phase value θ is reached, the process of S5 is not performed.

[0013] Next, in S6, after the processing time t has elapsed, the rotation of both spindles 1 and 2 is returned to synchronous rotation at equal angular velocities without being stopped (t4 in FIG. 3: second synchronous rotation step). At this time, the angular velocity of the synchronous rotation does not matter. In this way, by rotating synchronously again before stopping the laser irradiation, it is possible to prevent localized heating of the workpiece 4. Next, in S7, the laser irradiation by the laser unit 3 is stopped (t5 in FIG. 3: heating stopping step). Next, in S8, the synchronous rotation of both spindles 1 and 2 is stopped (t6 in FIG. 3), and the synchronous control of both spindles 1 and 2 is released (release step). By stopping the heating after the synchronous rotation in this way and stopping the rotation while maintaining the synchronization of both spindles 1 and 2, it is possible to suppress the generation of excess torsional torque in the workpiece 4.

[0014] In this manner, in the twist processing method and lathe M of the above-described embodiment, both ends of the workpiece 4 are held by the opposing spindles 1, 2, and the workpiece 4 is heated by the laser unit 3 while the spindles 1, 2 are rotated synchronously, and after a predetermined heating time has elapsed, a twisting operation is applied to the workpiece 4 by setting a difference in the rotation speeds of the spindles 1, 2. Then, after the twisting operation is completed, the spindles 1, 2 are rotated synchronously again, and then the heating by the laser unit 3 and the synchronous rotation of the spindles 1, 2 are stopped in order. According to this configuration, the entire circumference of the workpiece 4 is softened by heating during rotation, i.e., the yield stress is reduced, and the load torque required for processing is reduced. Therefore, it is expected that chucking slippage will be suppressed and the return amount will be reduced by releasing the elastic strain, and twist processing with good phase positioning accuracy can be performed.

[0015] In particular, since the twisting process is performed on a lathe M capable of cutting, distortion or burrs that occur after the twisting process can be removed by cutting. In addition, the relationship between stress and strain is obtained from the load torque difference and phase difference between the two spindles 1, 2 when the workpiece 4 is in the elastic region immediately after the start of the twisting operation, and the amount of elastic strain return is estimated from the load torque difference between the two spindles 1, 2 when the twisting operation is completed. Compensatory twist control is then performed to compensate for this amount of return, making it possible to perform precise twist processing without taking into account the cross-sectional shape of the workpiece 4 and the elastic coefficient, which is difficult to identify due to its temperature dependence.

[0016] In the above embodiment, a laser unit is used as the heating device, but other devices such as an induction heater can also be used. In addition, although the twisting process is performed using a lathe, other machine tools may be used. Therefore, the orientation of the workpiece may be vertical or oblique instead of horizontal. The shape of the workpiece is not limited to the above. Furthermore, the twist processing machine is not limited to a machine tool, and other industrial machines can be used as long as they are equipped with two opposing rotating shafts, a heating device for the workpiece, and a control device for controlling each of the rotating shafts and the heating device. A machine dedicated to twist processing can also be used. [Explanation of symbols]

[0017] 1 Main spindle, 2 Counter spindle, 3 Laser unit, 4 Workpiece, 5 Heating area, 10 Control device.

Claims

1. A method for performing twist processing on a workpiece using two opposing rotation shafts, a workpiece heating device, and a control device that controls each of the rotation shafts and the heating device, comprising: a first synchronous rotation step of synchronously rotating the two rotation shafts while holding both ends of a workpiece by the two rotation shafts; a heating step of heating the workpiece by the heating device while rotating the two rotation shafts synchronously; a twist processing step of applying a twisting operation to the workpiece by setting a difference between the rotation speeds of the two rotating shafts after a predetermined heating time has elapsed since the start of heating in the heating step; a second synchronous rotation step of synchronously rotating the two rotating shafts after the twisting step is completed; a heating stopping step of stopping heating by the heating device during execution of the second synchronous rotation step; a release step of stopping the synchronous rotation of the two rotating shafts after the heating by the heating device is stopped; In addition to carrying out the above, a twisting operation in the twisting step, which is performed until a predetermined processing time has elapsed, the processing time being required to obtain a desired twist phase value by multiplying the rotational speed of each of the rotating shafts by the difference between the rotational speeds of the rotating shafts, the twisting operation being performed until a predetermined processing time has elapsed, the desired twist phase value being obtained by multiplying the rotational speed of each of the rotating shafts by the difference between the rotational speeds of the rotating shafts.

2. A method for performing twist processing on a workpiece using two opposing rotation shafts, a workpiece heating device, and a control device that controls each of the rotation shafts and the heating device, comprising: a first synchronous rotation step of synchronously rotating the two rotation shafts while holding both ends of a workpiece by the two rotation shafts; a heating step of heating the workpiece by the heating device while rotating the two rotation shafts synchronously; a twist processing step of applying a twisting operation to the workpiece by setting a difference between the rotation speeds of the two rotating shafts after a predetermined heating time has elapsed since the start of heating in the heating step; a second synchronous rotation step of synchronously rotating the two rotating shafts after the twisting step is completed; a heating stopping step of stopping heating by the heating device during execution of the second synchronous rotation step; a release step of stopping the synchronous rotation of the two rotating shafts after the heating by the heating device is stopped; In addition to carrying out the above, A twist processing method characterized in that the twisting operation in the twist processing step is performed by respectively setting the rotational speed of each of the rotating shafts and monitoring the phase difference of each of the rotating shafts until a desired twist phase value is obtained.

3. The twist processing method according to claim 1 or 2, characterized in that in the twist processing step, the stress-strain relationship in the elastic region of the workpiece is calculated based on the relationship between the load torque difference and phase difference of each of the rotating shafts immediately after the start of the twisting operation, the amount of elastic strain recovery after the release step is estimated from the load torque difference of each of the rotating shafts at the end of the twisting operation, and compensatory twist control is performed to compensate for the amount of elastic strain recovery.

4. A twist processing program for causing a control device of a twist processing machine having two opposing rotating shafts, a workpiece heating device, and a control device that controls each of the rotating shafts and the heating device to execute the twist processing method described in any one of claims 1 to 3.

5. A twist processing machine including two opposing rotary shafts, a work heating device, and a control device for controlling each of the rotary shafts and the heating device, a first synchronous rotation means for synchronously rotating the two rotary shafts while holding both ends of a workpiece; A heating means for heating the workpiece by the heating device while rotating the two rotary shafts synchronously; a twist processing means for applying a twisting action to the workpiece by setting a difference between the rotation speeds of the two rotating shafts after a predetermined heating time has elapsed since the start of heating by the heating device; a second synchronous rotation means for synchronously rotating the two rotating shafts after the execution of the twist processing means; a heating stop means for stopping heating by the heating device while the second synchronous rotation means is being executed; a release means for stopping the synchronous rotation of the two rotating shafts after the heating by the heating device is stopped; Equipped with A twist processing machine characterized in that the twisting operation in the twist processing means is performed until a predetermined processing time has elapsed, in which the rotational speed of each of the rotating shafts is set and a desired twist phase value is obtained by multiplying the rotational speed and the difference between the rotational speeds of each of the rotating shafts.

6. A twist processing machine including two opposing rotary shafts, a work heating device, and a control device for controlling each of the rotary shafts and the heating device, a first synchronous rotation means for synchronously rotating the two rotary shafts while holding both ends of a workpiece; A heating means for heating the workpiece by the heating device while rotating the two rotary shafts synchronously; a twist processing means for applying a twisting action to the workpiece by setting a difference between the rotation speeds of the two rotating shafts after a predetermined heating time has elapsed since the start of heating by the heating device; a second synchronous rotation means for synchronously rotating the two rotating shafts after the execution of the twist processing means; a heating stop means for stopping heating by the heating device while the second synchronous rotation means is being executed; a release means for stopping the synchronous rotation of the two rotating shafts after the heating by the heating device is stopped; Equipped with A twist processing machine characterized in that the twisting operation in the twist processing means is performed by setting the rotational speed of each of the rotating shafts and monitoring the phase difference of each of the rotating shafts until a desired twist phase value is obtained.

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