JP2001071196A - Press device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a press forming device in which excessive press force is not applied to a part to be pressed to a pressing fixture, there is no change in a press speed during pressing and defective part is not generated. SOLUTION: In a first process, when descending a pressing fixture 5, excessive pressing force is not applied to the part 10 and impact applied to the part 10 is eliminated by controlling a drive current to drive a servomotor 3 so that the pressing fixture is descended in a high speed immediately before a part 10 is pressed. In a second process, the part 10 is pressed at a constant pressure and the part 10 is precisely pressed with the objective pressing force when an output voltage of a load cell 7 reaches an objective voltage, by controlling a drive current value to drive the servomotor 3 so as to keep the objective voltage until a prescribed time elapses.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention controls a torque generated by the rotary drive unit by controlling a drive current value for driving the rotary drive unit based on a pressing force measured by a pressing force measuring device. The present invention relates to a pressure device as described above.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 6, a hydraulic cylinder 102 fixed to a base 101 and a pressing tool 10 pressed by a piston 103 of the hydraulic cylinder 102 are shown.
4, a guide bar 106 that is combined with a guide 105 to stabilize the linear movement of the pressing tool 104,
Pressurizing device provided with a component holder 109 for holding a component body 108 of a component 107 to be press-processed into a workpiece, and a pressure measuring device 110 for measuring the pressure of the component holder 109 (first conventional example) 100. The pressurizing device 100 controls the pressurizing speed (lowering speed) of the pressurizing tool 104 with the pressure generated by the hydraulic cylinder 102 to pressurize the component 107. Note that 111 is a controller, and 112 is a programmable controller.

[0003] Conventionally, Japanese Patent Application Laid-Open No. 10-24959 discloses
In Japanese Patent Application Publication No. 7-107, a motor torque control method that can always apply a target press force to a work during acceleration or deceleration by correcting a torque limit value corresponding to a target press force with a motor torque required for acceleration or deceleration. (Second conventional example) has been proposed.

Further, conventionally, Japanese Patent Application Laid-Open No. 9-85456
In the publication, the armature current of the servomotor is detected, and the detected armature current value is set so that the pressing force corresponding to the armature current of the servomotor increases the electrode pressing force every minute time. There has been proposed a pressure control method (third conventional example) in which current feedback control is performed so as to follow the set pressure, so that the electrode pressure during energization can be accurately and automatically controlled every minute time.

[0005]

However, in the pressurizing apparatus 100 of the first conventional example, the pressurizing speed of the pressurizing tool 104 cannot be changed on the way, resulting in an impulsive pressurization. There is a problem that the component 107 is damaged by the impact of the tool 104 colliding with the component 107 at high speed. In addition, when the thickness of the deformed part of the component 107 to be subjected to the pressure processing due to the pressure processing is small, the pressing speed of the pressing tool 104 varies, so that the impact force when the pressing tool 104 collides with the component 107 at high speed. , And an excessive force is applied to the component 107.

Further, there is also a problem that the pressurizing speed in the hydraulic cylinder 102 changes due to a change in the temperature of the hydraulic oil during use, the impact force varies, and the component 107 becomes dirty and defective due to leakage of the hydraulic oil. Has occurred. Then, a high-precision pressure measuring device 110 is disposed below the component holder 109, and the pressurizing tool 104 is lowered at a high speed by the hydraulic cylinder 102. When the pressurizing tool 104 collides with the component 107 at a high speed,
There is a possibility that the pressure measuring instrument 110 is damaged by the impact due to the collision. Therefore, the pressing tool 104 is moved at low speed to the part 1
In this case, it is conceivable that the pressing step (the step of lowering the pressing tool 104) takes a long time.

Further, in the pressure control method of the second conventional example, it is difficult to suppress a change in the output torque of the servomotor due to a change in the mechanical structure (thermal deformation, change in sliding, etc.) and heat generated by the servomotor. Therefore, there is a problem that the pressing force changes in a time series. Further, in the motor torque control method of the third conventional example, similar to the second conventional example,
There is a problem that it is difficult to obtain a predetermined pressing force depending on external factors.

[0008]

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to prevent a pressurizing force exceeding a predetermined pressurizing force from being applied to a part and to reduce a change in a pressurizing speed during pressurizing a part. It is an object of the present invention to provide a pressurizing device which does not generate any defective products. Another object of the present invention is to provide a pressurizing device capable of obtaining a predetermined pressing force even when heat is generated from a rotary drive unit, abrasion of a mechanical structure unit, thermal deformation, or a change in sliding. It is still another object of the present invention to provide a pressurizing device that can perform multi-stage pressurizing control and can instantaneously change a predetermined pressure according to a product.

[0009]

According to the first aspect of the present invention, the rotary drive unit rotates the rotary unit, the rotary converter converts the rotary motion into a linear motion, and moves the pressing tool toward the component. Thus, the component is pressed by the pressing tool. In the first pressing step, when the pressing tool is moved in the component direction, the rotation driving unit is controlled so that the pressing tool is moved to just before the pressing of the component. It is possible to prevent a pressing force exceeding a predetermined pressing force from being applied to the component.

In the second pressurizing step, when the component is pressurized by the pressurizing tool, the torque generated by the rotary drive unit is controlled based on the pressing force measured by the pressing force measuring means. In the two-pressurizing step, pressurization can be performed with a predetermined pressure with high accuracy. Furthermore, since the pressurizing tool is moved linearly by the rotary drive unit and the motion conversion unit, the use of oil can be minimized, or by pressing parts with the rotary drive unit and the motion conversion unit that do not use oil. No contamination due to oil leakage, etc., and no defective products.

According to the second aspect of the present invention, the pressing force measuring means is provided below the component holding portion, and the component holding portion is lifted up and separated from the pressing force measuring device by an elastic body during non-pressing processing. Accordingly, even if the pressing tool comes into contact with the component during the first pressing step, the impact force is reduced, so that it is possible to prevent a pressing force exceeding a predetermined pressing force from being applied to the component.

According to the third aspect of the present invention, when the pressing force measured by the pressing force measuring means is increased to the target pressing force or more in the second pressurizing step, the rotation drive unit is generated until a predetermined time elapses. By controlling the drive current value for driving the rotary drive unit so as to maintain the torque at a constant value, in the second pressurizing step, the part can be press-worked at a constant pressure. Can be pressed. Then, by controlling the generated torque of the rotary drive unit with a drive current value for driving the rotary drive unit, it is possible to accurately control the pressing force with a simple device.

According to the fourth aspect of the invention, in the first pressing step, the drive current value of the rotary drive unit is controlled so as to switch the pressing speed of the pressing tool to a high speed, so that the components are added. The time required for the pressurizing step for press working can be reduced. Also, in the second pressing step, the component holding unit is operated at a high speed when the pressing tool comes into contact with the component by controlling the drive current value of the rotary drive unit so as to switch the pressing speed of the pressing tool to a low speed. Thus, it is possible to prevent the pressing force measuring means from being damaged without colliding with the pressing force measuring means.

According to the fifth aspect of the present invention, when the moving position detecting means detects that the moving position of the pressing tool has reached a position just before the pressing of the component, the first pressing is performed. By switching from the step to the second pressing step, the pressing tool can be moved at a high speed until the moving position of the pressing tool is on the verge of pressing the part. The required time can be reduced. Further, when the pressing tool comes into contact with the component, the pressing speed of the pressing tool is reduced, so that the component holding unit does not collide with the pressing force measuring means at high speed. Thereby, it is possible to prevent the pressing force measuring means from being damaged.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Structure of Embodiment] An embodiment of the present invention will be described based on an embodiment with reference to the drawings. here,
FIG. 1 is a view showing the overall configuration of the press forming apparatus, and FIG. 2 is a view showing a control system of the press forming apparatus.

The press forming apparatus 1 according to the present embodiment includes a servomotor 3 rotatably held on at least one base 2, a motion converting unit 4 for receiving a rotation output of the servomotor 3, and a motion converting unit 4. The pressurizing tool 5 attached to the tip of the portion performing the linear motion of the above, the component holder 6 for holding the component 10 to be pressed by the pressurizer 5, and the pressing force applied to the component holder 6 A load cell 7 for measurement and a controller 9 as a calculating means for calculating a control value of the servomotor 3 are provided.

The component 10 includes a workpiece 11 to be pressed by the pressing tool 5, a component body (constituting a lower mold) 12 for holding the workpiece 11, and the like. The workpiece 11 is a circular plate having a small thickness, for example. In the component main body 12, a convex fitting portion to be fitted into the component holder 6, a concave holding portion for holding the workpiece 11, and an upper end surface of the component holder 6. An overhang portion is formed. And base 2
Are fixed to a fixing member (not shown).

The servo motor 3 corresponds to a rotary drive unit of the present invention, and a driver 3 constituting a motor drive circuit
By controlling the drive current value by a, the generated torque is controlled. The output shaft 13 of the servo motor 3 has
A small-diameter gear 14 for transmitting the rotation output of the servomotor 3 to the motion converter 4 is fixed.

In this embodiment, as shown in the time charts of FIGS. 5A and 5B, the rotation speed of the servomotor 3 is changed (increased speed) by controlling the torque generated by the servomotor 3. Or decelerate). In this embodiment,
The rotation speed of the servo motor 3 is from 0 rpm to 3000 rpm
m, and from 3000 rpm to 100 rpm
m is referred to as Hi speed, and the time when the rotation speed of the servo motor 3 is fixed at 100 rpm is referred to as Lo speed.

The motion converting section 4 is a ball screw mechanism for converting the rotary motion of the servomotor 3 into a linear motion, and includes a nut 22 to which a large-diameter gear 21 meshing with the gear 14 of the servomotor 3 is fixed. 22 and steel ball (ball)
, A guide 24 that prevents rotation of the screw shaft 23, and a plurality of guide bars 25 that are combined with the guide 24 to stabilize the linear movement of the screw shaft 23. ing.

The screw shaft 23 performs a linear motion (reciprocating motion in the vertical direction in the figure) of the motion conversion unit 4 and is disposed in the vertical direction in the figure. A screw-shaped groove 26 on which the steel ball rolls is formed in a portion where the screw shaft 23 and the nut 22 are opposed to each other, that is, on the outer periphery of the screw shaft 23.

The pressing tool 5 is fixed to the tip of the screw shaft 23 of the motion converting section 4 and is fixed to the guide 24,
An upper die that presses (presses) the workpiece 11 into a predetermined shape during a pressing step in which the pressurizing tool 5 descends to pressurize the workpiece 11 of zero.

The component holder 6 corresponds to the component holder of the present invention, and the shaft 3 is provided upright in the vertical direction (vertical direction) with respect to the surface direction of the base 31 fixed to the fixing member.
2 is slidably supported on the shaft 32 and is disposed above the load cell 7 by a coil spring 33 as an elastic body attached to the outer periphery of the shaft 32. The upper end surface of the component holder 6 is provided with a concave fitting portion into which the fitting portion of the component body 12 of the component 10 is fitted.

The load cell 7 corresponds to the pressing force measuring means of the present invention, and the constant elastic alloy (elastic body) 8 is deformed by applying a load (the pressing tool 5, the component holder 6, and the component 10). This is a strain gauge type load cell which detects a minute displacement and measures a pressing force applied to the component 10 (component holder 6). The load cell 7 generates an output voltage of, for example, 5 V when the applied pressure is 2t. The output of the load cell 7 is input to the controller 9 after being amplified by the amplifier 34.

The controller 9 corresponds to the drive control means of the present invention, and is a microcomputer having a CPU, a ROM, a RAM, and a timer circuit, and has a well-known configuration. The controller 9 communicates with a programmable controller 45 that outputs a control signal to machinery of all facilities including the press forming apparatus 1 of the present embodiment.

Also, the controller 9 is provided with the controller shown in FIGS.
As described above, the load cell 7, the position sensor 4
By controlling a drive current value for driving the servo motor 3 based on sensor signals from the encoders 1, 42, the encoder 43, the pressure setting device 44, and the like, and a control program stored in the ROM in advance, Change the generated torque.

The position sensor 41 is a moving position detecting means for detecting that the pressing tool 5 has reached the rising end position, and outputs a rising end signal of the pressing tool 5 when the pressing tool 5 reaches the rising end position. I do. The position sensor 42 is a moving position detecting means for detecting that the pressing tool 5 has reached the position before the rising end, and outputs a signal before the rising end of the pressing tool 5 when the pressing tool 5 reaches the position before the rising end. I do.

The encoder 43 corresponds to the rotation number detecting means of the present invention, and detects that the moving position of the pressing tool 5 has reached a position just before the workpiece 11 of the component 10 is subjected to the pressure processing. It is a moving position detecting means. In addition, the position immediately before the pressure processing of the component 10 means that the rising end of the pressing tool 5 is 0%.
And the position at which the pressing tool 5 contacts the workpiece 11 is 100
If it is%, it is a position where it becomes 99%.

The pressing force setter 44 sets the target pressing force to be applied to the component 10 by lowering the pressing tool 5 from 0 to 1
It is a target pressing force setting means that can be set continuously up to about 5t. In this embodiment, the target pressure is set to 2t.

The controller 9 outputs a fixed position signal to the programmable controller 45 when the pressing tool 5 reaches the rising end. After outputting the home position signal, the controller 9 outputs to the programmable controller 45 a pressurization OK signal for instructing the start of the next pressurization processing when the current pressurization processing is good.

Then, the controller 9 determines whether the control of the generated torque of the servomotor 3 has elapsed for a predetermined time (for example, one second) or more, or that the output shaft 13 of the servomotor 3 has been rotated for a predetermined time during the generated torque control of the servomotor 3. If the output voltage of the load cell 7 does not reach the target voltage (for example, 5 V when the target pressing force is 2 t) even after several rotations (for example, four rotations), it is determined that the current press working is defective. A pressurization NG signal for notification is output to the programmable controller 45.

The controller 9 has current value detecting means for detecting a driving current value for driving the servomotor 3, and the driving current value for the servomotor 3 detected by the current value detecting means is determined by a predetermined value. If it exceeds the value, the servo motor 3
Is maintained at a constant value.

Alternatively, the controller 9 has a pressing force comparing means for comparing the actual pressing force (the output voltage of the load cell 7) with the target pressing force (the target voltage of the load cell 7).
When the actual pressure increases beyond the target pressure, the torque generated by the servo motor 3 is held at a constant value until a predetermined time (for example, 0.5 seconds) elapses. Thereby, the component 10
Becomes constant pressure.

[Control Method of the Embodiment] Next, a control method of the press forming apparatus 1 of the present embodiment will be briefly described with reference to FIGS. Here, FIGS. 3 and 4 are flowcharts showing an example of the control program of the controller 9.

First, it is determined whether or not the pressing tool 5 is at the rising end position (step S1). This determination result is NO
In the case of (1), the home position return control for controlling the drive current value for driving the servomotor 3 so that the tip end surface of the pressing tool 5 returns to the rising end position is performed (step S2). Thereafter, step S1 is repeated.

If the decision result in the step S1 is YES, a speed compensation value of the pressing tool 5 is set. Specifically, the rotation speed of the servo motor 3 is set to a high speed (Hi speed) (step S3). Next, the drive current value of the servomotor 3 is controlled so that the pressing tool 5 descends at a high speed (step S4).

Next, the moving position of the pressing tool 5 reaches a position immediately before the pressing position (the contact position where the pressing tool 5 comes into contact with the workpiece 11) for pressing the workpiece 11 of the component 10. It is determined whether or not it has been detected. That is, the encoder 4
It is determined whether or not the rotation speed of the output shaft 13 of the servo motor 3 detected at 3 has reached a predetermined rotation speed or more (step S5). Here, the predetermined number of rotations is such that the output shaft 13 is rotated by a distance that is moved by a linear motion from the rising end of the pressing tool 5 to just before the pressing tool 5 comes into contact with the workpiece 11 of the component 10. What is necessary is just to match the required number of rotations.

If the result of this determination is NO, step S5 is repeated. Here, the above steps S3 to S5 correspond to the first pressurizing step of the present invention. Step S3
By the control processing of S5 to S5, the movement position control of the pressurizing tool 5 (the rotation speed control of the servo motor 3) is performed.

If the decision result in the step S5 is YES, a speed compensation value of the pressing tool 5 is set. Specifically, the rotation speed of the servo motor 3 is set to a low speed (Lo speed) (step S6). Next, the drive current value of the servo motor 3 is controlled so that the pressing tool 5 descends at a low speed (generated torque control means: step S7). By the control processing of these steps S6 and S7, the generated torque of the servo motor 3 is controlled.

Next, during the generated torque control of the servomotor 3 (second pressurizing step), the output voltage of the load cell 7 reaches a target voltage (for example, 5 V) arbitrarily set by the pressing force setter 44. It is determined whether or not it has been performed (step S8).
Alternatively, it is determined whether or not the generated torque of the servo motor 3 has suddenly increased by a predetermined value or more. Specifically, it is determined whether the drive current value of the servo motor 3 has increased from a certain value by a predetermined value or more.

If the result of this determination is NO, it is determined whether or not the generated torque control of the servomotor 3 has passed a predetermined time (for example, one second) or more (step S9). If the result of this determination is YES, the drive current value of the servomotor 3 is controlled so that the pressurizing tool 5 rises at a high speed (step S10). Next, a pressurization NG signal is output to the programmable controller 45 (step S11). Then return.

If the result of the determination in step S9 is NO, it is determined whether or not the output shaft 13 of the servo motor 3 has rotated a predetermined number of revolutions (for example, 4 revolutions) during the torque control of the servo motor 3. A determination is made (step S12). If the result of this determination is YES, the operation proceeds to step S10,
If the result of the determination is NO, the operation proceeds to step S7.

If the result of the determination in step S8 is YES, the drive current of the servo motor 3 is controlled so that the torque generated by the servo motor 3 is maintained at a constant value until a predetermined time (for example, 0.5 seconds) has elapsed. Control the value (step S
13). Here, the above steps S6, S7, S12,
S13 corresponds to the second pressurizing step of the present invention.

Next, a speed compensation value of the pressing tool 5 is set. Specifically, the rotation speed of the servo motor 3 is set to a high speed (Hi speed) (step S14). Next, the drive current value of the servo motor 3 is controlled so that the pressurizing tool 5 moves up at a high speed (step S15).

Next, it is determined whether or not it has been detected that the moving position of the pressing tool 5 has reached a position just before the rising end. That is, it is determined whether or not the position sensor 42 has detected that the pressing tool 5 has reached the position just before the rising end (step S16). If this determination result is NO, step S
Proceed to 14.

If the result of the determination in step S16 is YES
In this case, the speed compensation value of the pressing tool 5 is set.
Specifically, the rotation speed of the servo motor 3 is set to a low speed (Lo speed) (step S17). Next, the drive current value of the servo motor 3 is controlled so that the pressurizing tool 5 rises at a low speed (step S18).

Next, it is determined whether or not it has been detected that the moving position of the pressing tool 5 has reached the rising end. That is, it is determined whether or not the position sensor 41 has detected that the pressing tool 5 has reached the rising end (step S19). If this determination is NO, the process proceeds to step S17. here,
The above steps S14 to S19 correspond to the pressure release step.

If the result of the determination in step S19 is YES
In the case of (1), the home position signal is output to the programmable controller 45 (step S20). Next, the pressurization OK signal for instructing the start of the next pressurization processing is output to the programmable controller 45 when the current pressurization processing is good (step S21). Then return.

[Operation of the Embodiment] Next, the operation of the press forming apparatus 1 of the embodiment will be briefly described with reference to FIGS. Here, FIG. 5A is a time chart showing a change in the rotation speed of the servo motor 3 during the first and second pressurizing steps and the pressurizing and releasing step, and FIG. 5B is a time chart showing the first and second pressurizing steps. 6 is a time chart showing a change in a torque generated by a servomotor during a pressurizing step and a pressurizing release step.

First, the target pressing force of the pressing tool 5 (for example, 2
In order to set t), a target voltage (for example, 5 V) of the output voltage of the load cell 7 is set by operating the pressing force setter 44. Then, when the first pressing process is started, first, it is detected that the pressing tool 5 is at the rising end position (original position), and first, it is detected that the pressing tool 5 is at the rising end position. In this case, the drive current value for driving the servomotor 3 in the normal rotation direction is controlled so that the pressing tool 5 descends at a high speed.

Then, the generated torque of the servo motor 3 becomes 3
00%, the servo motor 3 is started, and the rotation speed of the output shaft 13 of the servo motor 3 becomes 3000 rpm.
Speed up gradually until Then, when the rotation speed of the output shaft 13 of the servo motor 3 becomes 3000 rpm, the rotation speed is maintained at 3000 rpm until a predetermined time elapses or a predetermined number of rotations are performed, so that the generated torque of the servo motor 3 becomes 50%. The drive current value for driving the servo motor 3 is controlled so as to be as follows.

Therefore, the output shaft 13 of the servomotor 3 rotates at a high speed, and the gear 14 attached to the output shaft 13 rotates at a high speed, so that the gear 21 meshed with the gear 14 also rotates at a high speed. Then, the nut 22 of the motion conversion unit 4 integrated with the gear 21 rotates, and the screw shaft 23 whose rotation is regulated by the guide 24 linearly moves downward. As a result, the pressing tool 5 fixed to the tip of the screw shaft 23 descends at high speed toward the component 10 held on the upper end surface of the component holding unit 6.

Then, in order to switch from high speed to low speed just before the lower end surface of the pressing tool 5 comes into contact with the upper end surface of the material 11 to be pressed of the component 10, a predetermined time has elapsed or a predetermined time has elapsed. After the number of rotations, the rotation speed of the output shaft 13 of the servo motor 3 is gradually reduced by setting the generated torque of the servo motor 3 to -300%.

When the rotation speed of the output shaft 13 of the servo motor 3 becomes 100 rpm, the first pressing step for controlling the position of the pressing tool 5 is followed by the second pressing step for controlling the generated torque of the servo motor 3. Switch to When the second pressing step is started and the pressing tool 5 comes into contact with the pressurized material 11 of the component 10 and moves (falls) to the processing position, the generated torque of the servomotor 3 becomes T in FIG. As shown by, the torque increases sharply from the value of the generated torque (for example, 50%).

At this time, since the pressing tool 5 moves to the processing position where the component 10 is pressed, a downward pressing force also acts on the component holding unit 6, so that the output voltage of the load cell 7 also increases rapidly. The target voltage is reached. Therefore, until a predetermined time (for example, 0.5 seconds) elapses, the servo motor 3
By controlling the drive current value for driving the servo motor 3 so that the generated torque becomes a torque (fluctuation) equivalent to the target voltage of the load cell 7, during the period from the start of pressurization to the end of pressurization of the component 10. Constant pressure processing in which the pressure applied to the component 10 is constant can be performed.

When a predetermined time has elapsed since the pressing tool 5 moved to the pressing position, the process is switched from the second pressing step to the pressure releasing step. When the pressure release step is started, the drive current value for driving the servomotor 3 in the reverse direction is controlled so that the pressure tool 5 moves up to just before the rising end position (original position).

Then, the generated torque of the servo motor 3 becomes-
At 300%, the rotation speed of the output shaft 13 of the servo motor 3 gradually increases to 3000 rpm. The rotation speed of the output shaft 13 of the servo motor 3 is 3000
When the rotation speed reaches rpm, a drive current value for driving the servo motor 3 so that the generated torque of the servo motor 3 becomes -50% in order to maintain the rotation speed at 3000 rpm until a predetermined time elapses or a predetermined number of rotations is performed. Is controlled.

Then, the pressing tool 5 is moved to the rising end position (original position).
In order to be able to switch from the high speed to the low speed just before the time, the torque generated by the servo motor 3 is set to 300% after the lapse of a predetermined time or a predetermined number of rotations, so that the output shaft 13 of the servo motor 3 Rotation speed gradually decreases. Then, when the rotation speed of the output shaft 13 of the servo motor 3 becomes 0 rpm, the pressurizing and releasing step ends.

[Effects of Embodiment] As described above, the press forming apparatus 1 of this embodiment drives the movement of the pressing tool 5 by the servo motor 3 so that the pressing tool 5 Since the pressing speed (lowering speed) can be reduced just before contacting the material 11, a pressing force exceeding a predetermined pressing force (target pressing force) is not applied to the component 10.

The pressing force is measured by the load cell 7 disposed below the component holder 6 and the measured pressing force is fed back to control the torque generated by the servo motor 3. The impact force when contacting the workpiece 11 can be significantly reduced. Further, it is possible to cope with a change in the pressing force due to the movement of the pressurizing tool 5 and the deformation of the workpiece 11, and the pressing force larger than the target pressing force is not applied to the component 10. The component 10 can be subjected to pressure processing (constant pressure processing) with a constant pressing force without falling below the pressure.

As a result, the pressing tool 5 can move the component 10 at high speed.
Since no collision occurs, no impact force is generated. Furthermore, by performing constant-pressure processing on the component 10 with a constant pressing force, stable pressure processing can be performed without any change during the second pressing step. In addition, by performing press working with a mechanism that does not use oil, it is possible to provide the press forming apparatus 1 that does not generate stains due to oil leakage or the like. The impact force when the pressing tool 5 comes into contact with the workpiece 11 can be greatly reduced.

Further, even if there is heat generation of the servomotor 3, abrasion of the mechanical structure, thermal deformation, and changes in sliding, the target pressing force can be obtained. Further, by operating the pressure setting device 44, the target pressure can be set in multiple stages, and the target pressure can be instantaneously changed according to the product. For example, product A is 1.5t, product B is 2.0t
t, the product C is changed instantaneously to 1.0t,..., etc., so that parts to be press-processed at different target pressures can flow in one line.

Here, a high-precision load cell 7 is disposed below the component holder 6, and the pressurizing tool 5 is lowered at high speed by the servo motor 3, and the pressurizing tool 5 collides with the component 10 at high speed.
There is a possibility that the load cell 7 is damaged by the impact due to the collision. Therefore, it is conceivable to lower the pressing tool 5 in the direction of the component 10 at a low speed.
There is a problem that a long time is required for the pressing step.

Therefore, in the present embodiment, the component holding portion 6 is disposed in a state of being lifted above the load cell 7 by a coil spring 33 as an elastic body mounted on the outer periphery of the shaft 32, and the torque generated by the servo motor 3 is set. Immediately before it is detected that the drive current value for driving the servo motor 3 suddenly increases (the drive current value for driving the servo motor 3), the descending speed of the pressurizing tool 5 is switched from high speed to low speed. Accordingly, it is possible to prevent the component holding unit 6 from colliding with the load cell 7 at high speed and damaging the load cell 7.

[Modification] In this embodiment, an example is described in which the strain gauge type load cell 7 is applied as the pressing force measuring means, but a thin film strain gauge type load cell and a capacitance type load cell are used as the pressing force measuring means. May be used. Further, the torque generated by the servomotor 3 was detected by the drive current value for driving the servomotor 3, but the torque generated by the rotary drive unit and the linear motion unit were measured using a strain gauge type torque meter or a phase difference detection type torque meter. The transmission torque may be detected.

In this embodiment, when the rotation speed of the output shaft 13 of the servomotor 3 detected by the rotation speed detecting means such as the encoder 43 reaches a predetermined rotation speed, the pressing tool 5 is moved from the rising end position. Although it is determined that the part 10 has been lowered to a position just before pressure processing (contact with the part 10), when a predetermined time has elapsed since the lowering of the pressing part 5, the pressing part 5 is raised. It may be determined that the component 10 has been moved from the end position to a position just before pressure processing (contact with the component 10).

A position sensor is provided at a position just before the pressing tool 5 comes into contact with the component 10, and when the position sensor outputs after the pressing tool 5 starts descending, the pressing tool 5 May be determined to have moved from the ascending end position to a position just before pressing the part 10 (contacting the part 10).

[Brief description of the drawings]

FIG. 1 is a schematic view showing an entire configuration of a press molding apparatus (Example).

FIG. 2 is a block diagram showing a control system of the press forming apparatus (Example).

FIG. 3 is a flowchart illustrating an example of a control program of a controller (embodiment);

FIG. 4 is a flowchart illustrating an example of a control program of a controller (embodiment);

FIG. 5A is a time chart showing changes in the rotation speed of the servomotor during the first and second pressing steps and the pressure releasing step, and FIG. 5B is a time chart showing the first and second pressing steps; 6 is a time chart showing a change in a generated torque of a servomotor during a pressure release step (Example).

FIG. 6 is a schematic diagram showing a general configuration of a conventional pressurizing device (first conventional example).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Press-forming apparatus (pressing apparatus) 3 Servo motor (rotation drive part) 4 Motion conversion part 5 Pressing tool 6 Parts holding part (parts holding part) 7 Load cell (pressing force measuring means) 9 Controller (driving part control means) 10 Parts 43 Encoder (rotation speed detection means)

Claims (6)

[Claims] (A) a rotary drive for generating a rotational force; (b) a motion converter for converting the rotary motion of the rotary drive into a linear motion; and (c) a linear motion by the motion converter. (D) a pressing force measuring means for measuring a pressing force applied to the component, and (e) pressing the component when moving the pressing tool in the component direction. A first pressurizing step of controlling the rotation drive unit so that the pressurizing tool moves to just before press working, and measuring by the pressing force measuring means when the pressurizing tool presses a part. A pressurizing device comprising: a driving unit control unit that performs a second pressurizing step of controlling a generated torque of the rotary driving unit based on a pressing force. 2. The pressurizing device according to claim 1, wherein the pressing force measuring means is disposed below a component holding portion that holds a component to be pressed by the pressurizing tool. The pressurizing device, wherein the portion is supported on the base so as to be linearly movable in a pressurizing direction, and is lifted and separated from the pressing force measuring means by an elastic body. 3. The pressurizing device according to claim 1, wherein the driving unit control means adjusts the pressing force measured by the pressing force measuring means to a target pressing force during the second pressing step. A pressurizing device that controls a drive current value for driving the rotary drive unit so that the generated torque of the rotary drive unit is maintained at a constant value until a predetermined time elapses after the increase. 4. The pressurizing device according to claim 1, wherein in the first pressurizing step, the pressurizing speed of the pressurizing tool is set higher than in the second pressurizing step. Controlling the drive current value for driving the rotary drive unit so as to switch at a high speed. In the second pressing step, the pressing speed of the pressing tool is switched to a lower speed than in the first pressing step. And a driving current value for driving the rotation driving unit. 5. The moving device according to claim 4, wherein the driving unit control means detects that the moving position of the pressing tool has reached a position just before press working of the component. Means for detecting the movement position of the pressurizing tool to reach a position just before pressure processing of the component by the movement position detection means. A pressure device characterized by switching to a pressure step. 6. The pressurizing device according to claim 5, wherein the moving position detecting means is a rotational speed detecting means for detecting a rotational speed of the rotary drive unit, and the driving unit control means is a control unit for controlling the rotational speed. When the number of rotations of the rotation drive unit detected by the detection means reaches a predetermined value, it is determined that the moving position of the pressurizing tool has reached a position just before pressing the part. Pressurizing device.