JP2022033563A - Press device - Google Patents

Abstract

To provide a press device capable of reducing deterioration of accuracy of press caused by warp of the press device and of pressing an object accurately.SOLUTION: A press device 1 includes: a ram 31 giving load to an object to be pressed; a drive part driving the ram 31; a detection part detecting a load value of the load of the ram 31 with respect to the object; and a control part controlling the drive part so that the ram 31 gives load to the object. The control part performs control to move the ram 31 for a set moving distance DS where press volume when the object is actually pressed is desired press volume DP or less on the basis of prior setting, calculates a moving distance shortage DT of the ram 31 that is short with respect to the desired press volume DP while the ram 31 is moving for the set moving distance DS on the basis of load value detected by the detection part, and performs control so that the ram 31 moves for the moving distance shortage DT.SELECTED DRAWING: Figure 1

Description

The present embodiment relates to a pressing device that presses an object.

A press device that presses an object by moving the ram up and down by a drive device such as a servo motor is known.

Japanese Unexamined Patent Publication No. 2002-66798 Japanese Unexamined Patent Publication No. 2008-119737

The press device presses the object with a high-pressure load by the ram. Since the object is pressed with a high load, the ram receives a reaction force from the object. Although the press device is robustly constructed, this reaction force causes bending. This deflection generally occurs in the direction that separates the ram from the object. Therefore, when the ram is moved by a preset movement distance and the object is pressed, the object is pressed with a pressing amount less than a desired amount, which is not desirable.

Further, when the ram is simply moved by the movement amount obtained by adding the correction amount set in advance to the set movement distance and the object is pressed, further bending is generated in the press device. This further deflection results in the object being pressed with less than the desired amount of pressing, which is not desirable.

The deflection generated in the press device may differ from object to object. In addition, the rigidity of the members constituting the press device may change due to secular variation and temperature change, and the deflection generated in the press device may differ. There is a problem that the object is not pressed accurately due to the bending generated in the pressing device.

The present invention has been made to solve the above-mentioned problems, and is a press device capable of accurately pressing an object by reducing deterioration of press accuracy due to bending of the press device. The purpose is to provide.

The press device of the present invention is characterized by having the following.
(1) A ram that applies a load to the object to be pressed.
(2) A drive unit that drives the ram.
(3) A detection unit that detects the load value of the load of the ram on the object.
(4) A control unit that controls the drive unit so that the ram applies a load to the object.
(5) The control unit controls to move the ram at a set movement distance in which the press amount when the object is actually pressed is equal to or less than the desired press amount based on the preset setting, and the ram is controlled. Calculates the insufficient movement distance of the ram that is insufficient for the desired press amount based on the load value detected by the detection unit while the ram is moving the set movement distance, and the ram determines the insufficient movement distance. Control to move.

The following configuration may be adopted in the press device of the present invention.
(1) The control unit controls to move the set movement distance and the insufficient movement distance without stopping the ram.
(2) The control unit calculates the amount of deflection due to the reaction force generated by the load applied to the object by the ram, based on the load value detected by the detection unit. , The insufficient travel distance is calculated based on the calculated amount of deflection.
(3) The control unit calculates the insufficient movement distance based on the amount of change of the load value detected by the detection unit with respect to the movement distance of the ram.
(4) The control unit detects the load value of the ram on the object by the detection unit, calculates the insufficient movement distance, and then controls to decelerate and move the ram.
(5) The control unit transmits a movement command for the set movement distance to the drive unit in several order, and then transmits a movement command for the insufficient movement distance.

According to the present invention, since the drive unit is controlled based on the set movement distance based on the preset setting and the insufficient movement distance which is the difference between the desired press amount, a press device capable of accurately pressing the object can be provided. Can be provided.

According to the present invention, the insufficient movement distance of the ram is calculated based on the load detected by the detection unit, and the drive unit is controlled so that the movement related to the set movement distance and the insufficient movement distance is moved without stopping the ram. Therefore, the load of the ram can be detected by the detection unit with high accuracy. As a result, the object can be pressed accurately regardless of the deflection of the press device, which differs for each object, and the change in the deflection generated in the press device due to aging or temperature change.

A perspective view showing the structure of the press device according to the first embodiment. Sectional drawing which shows the inside of the press apparatus which concerns on 1st Embodiment The block diagram which shows the structure of the press apparatus which concerns on 1st Embodiment The figure explaining the bending of the press apparatus which concerns on 1st Embodiment The figure which shows the program flow of the arithmetic part of the press apparatus which concerns on 1st Embodiment The figure explaining the relationship between the position of the ram of the press apparatus which concerns on 1st Embodiment, and the load. The figure which shows the program flow which accompanies the deceleration of the ram of the press apparatus which concerns on 1st Embodiment. The figure explaining the relationship between the position of the ram accompanied by the deceleration of the press apparatus which concerns on 1st Embodiment, and the load.

[First Embodiment]
[1-1. Outline configuration]
Hereinafter, the configuration of the press device 1 of the present embodiment will be described with reference to FIGS. 1 to 3.

As shown in FIGS. 1 to 3, the press device 1 includes a control unit 2, a pressurizing unit 3, a drive unit 4, a detection unit 5, a base 8, and a housing 9. The housing 9 is composed of an enclosure 9a, a support column 9b, and a casing 9c. The enclosure 9a, the support column 9b, and the casing 9c are made of a material such as aluminum or iron. The enclosure 9a supports the control unit 2, the pressurizing unit 3, the drive unit 4, and the detection unit 5. The enclosure 9a is fixed to the support column 9b, and the support column 9b is fixed to the base 8. The base 8 is made of a material such as aluminum or iron, and an object W to be pressed is placed on the base 8.

The pressurizing unit 3 has a ram 31 and a ball screw 32.

The ram 31 and the ball screw 32 are composed of blocks made of iron or the like. The inside of the ram 31 is formed to be hollow. The ram 31 has a female screw portion 31a inside and is screwed with the ball screw 32. The ball screw 32 is composed of a male screw. The ram 31 moves up and down as the ball screw 32 rotates, and presses the object W. Further, a strain-causing column 31b is provided at the end of the ram 31 that comes into contact with the object W. The strain-causing column 31b abuts on the object W and applies a load. The ram 31 is housed in the casing 9c and arranged in the enclosure 9a. The ram 31 is guided in the moving direction by the guide portion 6.

The ball screw 32 is connected to the drive unit 4. Driven by the drive unit 4, the ball screw 32 is rotated.

The drive unit 4 includes a power transmission unit 41, a servomotor 42, and an encoder 43.

The power transmission unit 41 has a pulley 41a, a belt 41c, and a pulley 41b. The power transmission unit 41 is arranged inside the enclosure 9a. The pulley 41b of the power transmission unit 41 is connected to the ball screw 32. The rotation of the pulley 41a is transmitted to the pulley 41b via the belt 41c, and the ball screw 32 rotates. The pulley 41a of the power transmission unit 41 is connected to the servomotor 42.

The servomotor 42 is connected to the control unit 2. The rotation amount of the servomotor 42 is controlled by the control unit 2. The servomotor 42 rotates the pulley 41a of the power transmission unit 41. The servomotor 42 is arranged inside the enclosure 9a.

The encoder 43 detects the amount of rotation of the servomotor 42. The encoder 43 is connected to the control unit 2. The encoder 43 detects the amount of rotation of the servomotor 42, encodes it, and outputs it to the control unit 2. The encoder 43 is arranged in the servomotor 42.

The detection unit 5 is composed of a strain gauge 51 and a communication unit 52. The strain gauge 51 is composed of a load sensor such as a piezo element. The strain gauge 51 is arranged on a surface opposite to the end portion of the strain generating column 31b of the ram 31 that abuts on the object W. The strain gauge 51 detects the load of the ram 31 on the object W. The strain gauge 51 transmits an analog signal applied to the detected load to the communication unit 52. The analog signal applied to the load detected by the strain gauge 51 may be the resistance value of the strain gauge 51.

The communication unit 52 is composed of an analog-to-digital conversion circuit and a transmission circuit. The communication unit 52 is arranged inside the enclosure 9a. The communication unit 52 amplifies the analog signal applied to the load received from the sensor 51, converts it into a digital signal, and transmits it to the control unit 2.

The control unit 2 is mainly composed of a microcomputer. The control unit 2 is arranged inside the enclosure 9a. The control unit 2 controls the pressurizing operation of the object W by the pressurizing unit 3. The control unit 2 is connected to the servomotor 42 of the drive unit 4 and controls the rotation amount of the servomotor 42. The control unit 2 is connected to the encoder 43 of the drive unit 4 and receives the coded rotation amount of the servomotor 42. The control unit 2 is connected to the communication unit 52 of the detection unit 5 and receives a digital signal applied to the load detected by the sensor 51.

The control unit 2 includes a calculation unit 20, a program storage unit 21, a display unit 22, an operation unit 23, a primary storage unit 24, a parameter storage unit 25, a command pulse generation unit 26, a servomotor driver 27, and an encoder position counter 28. To.

The program storage unit 21 is composed of a memory made of a semiconductor or a storage device such as a hard disk. The program storage unit 21 is connected to the arithmetic unit 20. The program storage unit 21 stores a program that controls the operation of the arithmetic unit 20. The arithmetic unit 20 operates based on the program stored in the program storage unit 21.

The display unit 22 is composed of a plasma display, a liquid crystal display, or the like. The display unit 22 is connected to the calculation unit 20. The display unit 22 is controlled by the calculation unit 20 and displays the set parameters, operating state, and the like.

The operation unit 23 is composed of a switch 231 and an input circuit 232. The operation unit 23 is connected to the calculation unit 20. The switch 231 is operated by an operator when the pressing operation of the object W is started or when the pressing operation is stopped. The operation unit 23 detects that the switch 231 has been operated by the input circuit 232 and outputs it to the calculation unit 20.

The temporary storage unit 24 is composed of a memory made of a semiconductor or a storage device such as a hard disk. The temporary storage unit 24 is connected to the arithmetic unit 20. The temporary storage unit 24 is controlled by the calculation unit 20 and stores temporary data in the calculation process.

The parameter storage unit 25 is composed of a memory made of a semiconductor or a storage device such as a hard disk. The parameter storage unit 25 is connected to the calculation unit 20. The parameter storage unit 25 stores the position ZT. The position ZT is the position of the set movement distance DS in the direction of the base 8 from the position ZS where the contact of the ram 31 with the object W starts. The set movement distance DS is the difference between the position ZS and the position ZT. The set moving distance DS is the moving distance of the ram 31 assuming that the press device 1 does not bend. The set movement distance DS is equal to the desired press amount DP for pressing the object W.

The position ZT is set by the operator before the start of the pressing operation of the object W, and is stored in the parameter storage unit 25 in advance. In addition to the position ZT, the parameter storage unit 25 may store a preset position ZS and a set movement distance DS. Further, the parameter storage unit 25 stores the deflection coefficient K used for calculating the insufficient movement distance DT. The deflection coefficient K is preset by the operator before the start of the press operation.

The command pulse generation unit 26 is configured by a pulse generation circuit. The command pulse generation unit 26 is connected to the calculation unit 20 and the servomotor driver 27. The command pulse generation unit 26 receives a movement command, which is a command to output a pulse from the calculation unit 20, and converts it into a pulse for controlling the rotation amount of the servomotor 42. The movement command converted into a pulse is input to the servomotor 42 via the servomotor driver 27.

The servomotor driver 27 is composed of a servomotor drive circuit. The servomotor driver 27 is connected to the command pulse generation unit 26 and the servomotor 42. The servomotor driver 27 amplifies the pulse applied to the movement command converted by the command pulse generation unit 26, and drives the servomotor 42. The servomotor 42 rotates at an angle of rotation that is directly proportional to the number of pulses output from the command pulse generation unit 26. When the servomotor 42 rotates at a desired angle of rotation, the ram 31 moves at a desired amount of movement.

Further, the servomotor driver 27 is connected to the encoder 43 and the calculation unit 20 of the drive unit 4. The servomotor driver 27 receives the rotation angle of the servomotor 42 detected by the encoder 43 and transmits it to the calculation unit 20.

The encoder position counter 28 is configured by a counter circuit. The encoder position counter 28 is connected to the encoder 43 of the drive unit 4 and the calculation unit 20. The encoder position counter 28 receives the amount of rotation of the servomotor 42 encoded from the encoder 43. The encoder position counter 28 accumulates and counts the amount of rotation of the servomotor 42, and transmits it to the calculation unit 20. The calculation unit 20 detects the movement amount and the speed of the ram 31 based on the cumulatively counted rotation amount output from the encoder position counter 28.

The arithmetic unit 20 is composed of a microcomputer. The calculation unit 20 controls the pressurizing unit 3 via the command pulse generation unit 26, the servomotor driver 27, and the drive unit 4 so as to press the object W with a desired press amount DP. The calculation unit 20 controls the display operation of the display unit 22. Further, the calculation unit 20 detects an operation by the operator via the operation unit 23. The calculation unit 20 controls the storage operation of the primary storage unit 24 and the parameter storage unit 25.

The calculation unit 20 receives the rotation angle of the servomotor 42 detected by the encoder 43 via the servomotor driver 27. Further, the calculation unit 20 detects the movement amount and the speed of the ram 31 based on the cumulatively counted rotation amount output from the encoder position counter 28. The calculation unit 20 receives a digital signal applied to the load of the ram 31 of the pressurizing unit 3 from the detection unit 5. The arithmetic unit 20 operates based on the program stored in the program storage unit 21.

[1-2. Action]
Next, the operation of the press device 1 of the present embodiment will be described with reference to FIGS. 1 to 6. The parameters in this embodiment are as follows.
Desired press amount DP [mm]: The desired press amount DP is the position where the ram 31 abuts on the object W at the start of pressing when the desired press is performed on the object W, and the ideal press is performed. It is a difference distance from the position after processing of the later ram 31. The distance from the position XS to the position XT, which will be described later, corresponds to the desired press amount DP [mm].
Set movement distance DS [mm]: The set movement distance DS is a distance for moving the ram 31 based on the position ZT stored in advance in the parameter storage unit 25. The set movement distance DS is the difference between the position ZS and the position ZT. The set moving distance DS is the moving distance of the ram 31 assuming that the press device 1 does not bend. The set movement distance DS is equal to the desired press amount DP for pressing the object W. Since the ram 31 receives a reaction force from the object W and a bending amount δ is generated in the pressing device 1, the pressing of the object W by the set moving distance DS becomes less than the desired pressing amount DP.
Insufficient movement distance DT [mm]: The insufficient movement distance DT is the difference distance between the desired press amount DP and the set movement distance DS.
Difference R [mm]: The difference R is a distance corresponding to the number of "accumulated pulses" when the ram 31 is driven by the servomotor 42.
Deflection amount δ [mm]: The deflection amount δ is a distance corresponding to the deflection generated in the press device 1 due to the reaction force received by the ram 31 from the object W.
Position ZS [mm]: Position ZS is the position where the contact of the ram 31 with the object W starts. Position ZS is equal to position XS.
Position Z0 [mm]: Position Z0 is a position where the calculation unit 20 calculates the insufficient movement distance DT.
Position ZT [mm]: The position ZT is the position of the set movement distance DS in the direction of the base 8 from the position ZS where the contact of the ram 31 with the object W starts. The position ZT is stored in advance in the parameter storage unit 25.
Position XS [mm]: Position XS is a position where the contact of the ram 31 actually starts with the object W. Position XS is equal to position ZS.
Position XT [mm]: Position XT is the position where the pressing of the object W is actually completed. The distance from the position XS to the position XT is equal to the sum of the set movement distance DS and the insufficient movement distance DT.
Load value F (Z0) [N]: The load value F (Z0) is the load value of the ram 31 at the position Z0.
Load value F (ZT) [N]: The load value F (ZT) is the load value of the ram 31 at the position ZT.
Load value F (XT) [N]: The load value F (XT) is the load value of the ram 31 at the position XT.
Deflection coefficient K [mm / N]: The deflection coefficient K is a proportional coefficient of the load value F [N] with respect to the deflection amount δ.
Load slope value W (Z0) [N / mm]: The load slope value W (Z0) is the amount of change in the load value F (Z0) with respect to the moving distance of the ram 31 at the position Z0.
Load slope value W (ZT) [N / mm]: The load slope value W (ZT) is the amount of change in the load value F (ZT) with respect to the moving distance of the ram 31 at the position ZT.
Load slope value W (XT) [N / mm]: The load slope value W (XT) is the amount of change in the load value F (XT) with respect to the moving distance of the ram 31 at the position XT.
Movement speed V [mm / S]: The movement speed V is the movement speed of the ram 31.
Coefficient SV [S]: The coefficient SV is an overshoot distance coefficient.

[Operation of arithmetic unit 20]
The calculation unit 20 of the control unit 2 controls the pressurizing unit 3 via the command pulse generation unit 26, the servomotor driver 27, and the drive unit 4, and presses the object W. The calculation unit 20 detects an operation indicating that the operator starts pressing by the operation unit 23, and controls the operation of pressing the object W.

The ram 31 of the pressurizing unit 3 moves based on the movement command transmitted to the calculation unit 20, and the object W is pressed. First, the calculation unit 20 controls to move the ram 31 and press the object W by the set movement distance DS based on the position ZT preset in the parameter storage unit 25.

The pressing device 1 presses the object W with a high-pressure load by the ram 31. Since the object W is pressed with a high-pressure load, the ram 31 receives a reaction force from the object W. Although the press device 1 is robustly configured, as shown in FIG. 4, this reaction force causes bending of the bending amount δ. This bending generally occurs in the direction in which the ram 31 and the object W are separated from each other.

Therefore, when the ram 31 is moved by the set movement distance DS based on the preset position ZT and the object W is pressed, the object W is pressed with a press amount less than the desired DP.

It is also conceivable to simply store the insufficient movement distance DT as a correction amount in the parameter storage unit 25, add the preset insufficient movement distance DT to the set movement distance DS, and move the ram 31. However, when the object is further pressed by the insufficient movement distance DT, further bending occurs in the press device 1.

The reaction force that the ram 31 receives from the object W when the ram is moved by the insufficient movement distance DT is larger than the reaction force that the ram 31 receives when the ram is moved by the set movement distance DS. Therefore, in general, the amount of deflection δ generated in the press device 1 becomes larger when pressed by the insufficient moving distance DT than when pressed by the set moving distance DS due to further bending. When the ram 31 is moved by adding it to the set movement distance DS by the preset shortage movement distance DT, the object is pressed with less than the desired press amount DP due to this further bending. Not desirable.

The calculation unit 20 of the control unit 2 calculates the set movement distance DS based on the preset position ZT and the insufficient movement distance DT which is the difference between the desired press amount DP and the set movement distance DS. The calculation unit 20 controls the drive unit 4 based on the insufficient movement distance DT, and operates the pressurizing unit 3. The calculation unit 20 calculates the insufficient movement distance DT based on the load detected by the detection unit 5, and moves the distance applied to the set movement distance DS and the insufficient movement distance DT without stopping the ram 31.

The calculation unit 20 of the control unit 2 calculates the amount of deflection δ due to the reaction force generated by the load applied to the object W by the ram 31 based on the load value F detected by the detection unit 5. Then, the insufficient travel distance DT is calculated based on the calculated deflection amount δ.

The calculation unit 20 of the control unit 2 calculates the insufficient movement distance DT based on the load inclination value W, which is the amount of change of the load value F detected by the detection unit 5 with respect to the movement distance of the ram 31.

The calculation unit 20 of the control unit 2 transmits a movement command for the set movement distance DS to the drive unit 4, and then transmits a movement command for the insufficient movement distance DT.

The arithmetic unit 20 of the control unit 2 performs the following operations according to the program shown in FIG. 5 stored in the program storage unit 21.

First, the arithmetic unit 20 detects that the switch 231 of the operation unit 23 has been pressed and starts processing (step S01). At the start of the pressing operation, the operator presses the switch 231 instructing the start of the pressing operation.

Next, the calculation unit 20 reads out the position ZT stored in the parameter storage unit 25 (step S02). The position ZT determines the target stop position of the ram 31 at the end of the press. The position ZT is the position of the set movement distance DS in the direction of the base 8 from the position ZS where the contact of the ram 31 with the object W starts. The set movement distance DS is the difference between the position ZS and the position ZT. The set moving distance DS is the moving distance of the ram 31 assuming that the press device 1 does not bend. The set movement distance DS is equal to the desired press amount DP for pressing the object W.

Next, the calculation unit 20 transmits a movement command to the command pulse generation unit 26 (step S03). The calculation unit 20 moves the ram 31 from the position ZS to the position ZT which is the set movement distance DS by the movement command. The movement command converted into a pulse by the command pulse generation unit 26 is input to the servomotor 42 via the servomotor driver 27. As a result, the servomotor 42 starts rotating. The rotation of the servomotor 42 is transmitted via the power transmission unit 41, the ball screw 32 rotates, and the ram 31 moves.

The servomotor 42 rotates at an angle of rotation that is directly proportional to the number of pulses output from the command pulse generation unit 26. First, the ram 31 is moved to position ZS. At this point, since the ram 31 has not received a reaction force, the position ZS is equal to the position XS where the contact of the ram 31 actually starts with the object W.

After that, the calculation unit 20 transmits a movement command corresponding to the set movement distance DS to the command pulse generation unit 26 in several orders. For example, when the servomotor 42 moves the distance required for the set movement distance DS with 10,000 pulses, the calculation unit 20 makes 1000 times so that 10 pulses are output from the command pulse generation unit 26 every 1 ms. The movement command is separately transmitted to the command pulse generation unit 26.

Next, the calculation unit 20 determines whether the ram 31 has reached the position Z0 (step S04). At position Z0, the calculation unit 20 calculates the insufficient movement distance DT. The position Z0 is a position before the ram 31 makes a movement related to the insufficient movement distance DT and before the movement related to the set movement distance DS is completed. The position of the ram 31 is determined based on the cumulative amount of rotation of the servomotor 42 accumulated and counted by the encoder position counter 28.

If it is not determined that the ram 31 has reached the position Z0, the arithmetic unit 20 repeats the operation of step S03. When it is determined that the ram 31 has reached the position Z0, the arithmetic unit 20 performs the operation of step S05.

When the ram 31 determines that the position Z0 has been reached, the arithmetic unit 20 receives the load value F (Z0) at the position Z0 (step S05). The load value F (Z0) is detected by the detection unit 5 and transmitted to the control unit 2. FIG. 6 shows a graph showing the relationship between the position of the ram 31 and the load value F (Z0).

Next, the calculation unit 20 calculates the load inclination value W (Z0) (step S06). The calculation of the load inclination value W (Z0) is performed based on the load value F (Z0) received in step S05. The load inclination value W (Z0) is the amount of change in the load value F (Z0) with respect to the moving distance of the ram 31. The load slope value W (Z0) corresponds to the differential value of the load value F (Z0) at the position Z0 of the ram 31. The method of calculating the load inclination value W (Z0) will be described later.

Next, the calculation unit 20 calculates the insufficient movement distance DT (step S07). The insufficient movement distance DT calculates the amount of deflection δ due to the reaction force generated by the load applied to the object W by the ram 31 based on the load value F (Z0) detected by the detection unit 5. Then, it is calculated based on the calculated deflection amount δ. Further, the insufficient movement distance DT is calculated based on the load inclination value W (Z0) which is the amount of change of the load value F (Z0) detected by the detection unit 5 with respect to the movement distance of the ram 31. The load inclination value W (Z0) is calculated in step S06. The method of calculating the insufficient travel distance DT will be described later.

After reaching the position Z0, the ram 31 is moved to the position ZT at the time when the calculation unit 20 calculates the insufficient movement distance DT. The object W is pressed with the distance of the set movement distance DS from the position XS to the position ZT. The set travel distance DS is less than the desired press amount DP.

Next, the calculation unit 20 transmits a movement command for the insufficient movement distance DT to the command pulse generation unit 26 (step S08). The command pulse generation unit 26 generates a pulse that controls the amount of rotation of the servomotor 42 applied to the insufficient movement distance DT. The generated pulse is input to the servomotor 42 via the servomotor driver 27. As a result, the servo motor 42 rotates. The rotation of the servomotor 42 is transmitted to the power transmission unit 41 and the ball screw 32, and the ram 31 moves the insufficient movement distance DT.

As a result, the ram 31 is moved to position XT. The object W is pressed with the distance from the position XS to the position XT. The distance from position XS to position XT is equal to the desired press amount DP. As a result, the object W is pressed with a desired pressing amount DP.

After that, the calculation unit 20 stops the press operation.

[Calculation of insufficient travel distance DT by calculation unit 20]
Next, the calculation unit 20 describes the calculation of the insufficient movement distance DT by the calculation unit 20. Since the pressing device 1 presses the object with a high pressure load by the ram 31, the ram 31 receives a reaction force from the object W. As shown in FIG. 4, this reaction force causes the press device 1 to bend due to the amount of bending δ. This bending generally occurs in the direction in which the ram 31 and the object W are separated from each other. Therefore, when the ram 31 is moved by the set movement distance DS and the object W is pressed, the object W is pressed with a press amount less than the desired DP.

Further, when the ram 31 is simply moved by the movement amount obtained by adding the correction amount set in advance to the set movement distance DS and the object W is pressed, further bending is generated in the press device 1. Due to this further bending, the object W is pressed with a pressing amount of less than the desired DP.

Further deflection generated in the press device 1 may differ depending on the object W. In addition, the rigidity of the members constituting the press device 1 may change due to secular variation or temperature change, and the deflection generated in the press device 1 may differ.

In order to solve this problem, the calculation unit 20 calculates the amount of deflection δ generated in the press device 1 for each object W individually, and calculates the insufficient movement distance DT based on the calculated amount of deflection δ.

The ram 31 receives a reaction force from the object W, and the enclosure 9a and the support column 9b of the press device 1 bend with respect to the base 8. This deflection causes the ram 31 to be separated from the base 8. As a result, the object W is pressed with a short distance corresponding to the deflection amount δ with respect to the desired press amount DP.

The amount of deflection δ generated in the press device 1 is directly proportional to the load value F [N] applied to the ram 31. The relationship between the amount of deflection δ [mm] and the load value F [N] is expressed by (Equation 1).
δ [mm] = K [mm / N] * F [N]
(Equation 1)
In (Equation 1), K [mm / N] is a deflection coefficient. The deflection coefficient K [mm / N] is a proportional coefficient of the load value F [N] with respect to the deflection amount δ.

The deflection coefficient K [mm / N] is preset and stored in the parameter storage unit 25. The deflection coefficient K [mm / N] is the load value F [N] applied to the ram 31 and the deflection by lowering the ram 31 with a length measuring device for measuring the distance between the tip of the ram 31 and the base 8. The quantity δ [mm] is measured in advance and calculated.

The deflection coefficient K [mm / N] may be one value in all sections of the moving distance of the ram 31. Further, the deflection coefficient K [mm / N] may be a different value for each section in the moving distance of the ram 31. The deflection coefficient K [mm / N] is not always constant in all sections of the moving distance of the ram 31. The deflection coefficient K [mm / N] may be expressed by, for example, a polygonal line approximation for each section in the moving distance of the ram 31. The section in the moving distance of the ram 31 may be divided into N pieces, and the coefficient of the i-th section may be a deflection coefficient Ki [mm / N] (i = 1 to N).

The relationship between the position Z [mm] of the ram 31 assuming that the pressing device 1 does not bend and the position X [mm] of the ram 31 when the pressing device 1 bends when the object W is pressed. Is expressed by (Equation 2).
X [mm] = Z [mm] + δ [mm]
(Equation 2)
In (Equation 2), δ [mm] is the amount of deflection δ [mm] in the above-mentioned (Equation 1).

In FIG. 6, the position where the ram 31 is moved by the set movement distance DS based on the preset position ZT is represented by Z, and the actual position of the ram 31 when the press device 1 is bent is represented by X. The position where the ram 31 starts to come into contact with the object W is the position ZS or the position XS, and the position of the ram 31 at the time when the pressing of the object W is completed is XT.

The distance from the position ZS to the position ZT when the press device 1 is not bent is the set movement distance DS. The set travel distance DS is equal to the desired press amount DP.

If there is deflection, the distance from position XS to position XT is equal to the desired press amount DP. The desired press amount DP corresponds to the sum of the set movement distance DS and the insufficient movement distance DT. The positions ZS and XS are the positions where the ram 31 starts to come into contact with the object W, and are the same positions.

The calculation unit 20 transmits a movement command corresponding to the set movement distance DS to the command pulse generation unit 26 in order to move the ram 31. The servomotor 42 rotates at an angle of rotation that is directly proportional to the number of pulses output from the command pulse generation unit 26. The servomotor 42 starts rotating based on the number of pulses output from the command pulse generation unit 26.

However, after a plurality of pulses are output from the command pulse generation unit 26, there is a time delay until the rotation of the servomotor 42 reaches the commanded rotation amount. Of the plurality of pulses output from the command pulse generation unit 26, the pulse that is not allocated to the rotation amount of the servomotor 42 due to this time delay is called a “pooled pulse”.

The calculation unit 20 transmits a movement command to the command pulse generation unit 26. The command pulse generation unit 26 converts a movement command into a pulse and outputs a command pulse having a quantity to move to the position ZT to the servomotor 42 (corresponding to step S03). The calculation unit 20 transmits a movement command corresponding to the set movement distance DS so that the command pulse generation unit 26 outputs the command pulse in several orders. Assuming that no bending occurs in the pressing device 1, the position XT = ZT of the ram 31, and it is not necessary to calculate the bending amount δ [mm] by (Equation 1).

However, bending occurs in the pressing device 1 during pressing. The calculation when the press device 1 is bent is performed as follows.

First, the calculation unit 20 controls to move the set movement distance DS to the ram 31, assuming that the press device 1 does not bend. That is, the arithmetic unit 20 transmits a movement command for moving the ram 31 from the position ZS to the position ZT to the command pulse generation unit 26. The command pulse generation unit 26 converts the movement command into a pulse having a quantity for moving the ram 31 to the position ZT, and outputs the movement command to the servomotor 42.

The calculation unit 20 transmits a movement command for moving the ram 31 to the position ZT to the command pulse generation unit 26 in several orders (step S03). Further, the calculation unit 20 receives the load value F (Z0) at this time point from the detection unit 5 (step S05). The calculation unit 20 calculates the load inclination value W (Z0) based on the load value F (Z0) (step S06).

After that, the calculation unit 20 calculates the insufficient movement distance DT (step S07). The shortage travel distance DT is calculated at the time after the ram 31 reaches the position Z0 and before the position ZT is reached.

The position Z0 is detected by calculating the movement amount of the ram 31 by the calculation unit 20 based on the cumulatively counted rotation amount of the servomotor 42 output from the encoder position counter 28. As the load value F (Z0), the analog signal applied to the load of the ram 31 with respect to the object W detected by the strain gauge 51 is converted into a digital signal by the communication unit 52 and input to the calculation unit 20.

The load inclination value W is an amount of increase of the load value F with respect to a unit distance, and has the same dimension [N / mm] as the spring constant. The load slope value W is a derivative of the load value F with respect to the position and is expressed by (Equation 3).
W [N / mm] = dF [N] / dZ [mm]
(Equation 3)

The load inclination value W [N / mm] is the inclination in the graph shown in FIG. 6 with the position Z [mm] as the horizontal axis and the load value F [N] as the vertical axis.

・・・・・（式４） It is preferable to calculate the slope of the graph by linear regression calculation in order to reduce the influence of variation and calculate the slope value with high reliability. The data indicating the position Z [mm] of the tip of the ram 31 is (Z1, Z2 ... Zn), and the data indicating the position Z [mm] load value F [N] at each position is (F1, F2 ... Fn). ), Draw a regression line for each point. The slope of the regression line is expressed by (Equation 4).

(Equation 4)

The calculation unit 20 calculates the load inclination value W (Z0) [N / mm] based on the set of n data until the position Z0 [mm] is reached by (Equation 4).

When the arithmetic unit 20 moves according to the position Z0 [mm] of the ram 31 at the time when all the movement commands related to the set movement distance DS to be output separately are transmitted, and all the movement commands related to the set movement distance DS. The difference R [mm] from the position ZT [mm], which is the assumed target position, is calculated. The difference R [mm] is expressed by (Equation 5).
ZT [mm] = Z0 [mm] + R [mm]
(Equation 5)

The difference R [mm] corresponds to the number of "accumulated pulses" in the case where the ram 31 is driven by the servomotor 42. The quantity of "accumulated pulse" is directly proportional to the moving speed V [mm / S] of the ram 31. The relationship between the difference R [mm] and the moving speed V [mm / S] of the ram 31 is expressed by (Equation 6).
R [mm] = SV [S] * V [mm / S]
(Equation 6)
In (Equation 6), SV [S] is a coefficient.

The coefficient SV [S] differs depending on the configuration of the drive unit 4 and the pressurizing unit 3, the feedback gain of the servomotor driver 27, and the like. The coefficient SV [S] is calculated in advance and stored in the parameter storage unit 25. The coefficient SV [S] inputs a pulse to the servomotor 42 so as to change the moving speed V [mm / S] of the ram 31, and the ram from the time when the input of the pulse is stopped until the movement of the ram 31 is stopped. It is calculated by measuring the moving distance of 31 and measuring the inclination of the measured moving distance of the ram 31.

Assuming that the load inclination value W [N / mm] does not change even if the ram 31 moves by the difference R [mm] which is a minute distance, the load inclination value W (ZT) [N /] at the position ZT [mm] mm] is represented by (Equation 7).
W (ZT) [N / mm] = W (Z0 + R) [N / mm] = W (Z0) [N / mm]
(Equation 7)

After calculating the shortage movement distance DT, the calculation unit 20 transmits a movement command related to the shortage movement distance DT to the command pulse generation unit 26 and converts it into a pulse (step S08). The command pulse generation unit 26 outputs a pulse that controls the amount of rotation of the servomotor 42. As a result, the ram 31 travels a distance corresponding to the insufficient movement distance DT. The calculation unit 20 controls to move the ram 31 to the target position XT.

The calculation unit 20 calculates the insufficient movement distance DT as follows. The difference between the position Z0 [mm] and the position XT, which is the target position, is very small. Therefore, assuming that the load inclination value W (XT) [N / mm] at the position XT [mm] is the same as the load inclination value W (ZT) [N / mm] at the position ZT [mm], the position XT The load inclination value W (XT) [N / mm] in [mm] is expressed by (Equation 8).
W (XT) [N / mm] = W (ZT + DT) [N / mm]
= W (ZT) [N / mm] = W (Z0 + R) [N / mm] = W (Z0) [N / mm]
(Equation 8)

(Equation 3) is modified, and the amount of increase dF of the load value F with respect to the unit distance is expressed by (Equation 9).
dF [N] = W [N / mm] * dZ [mm]
(Equation 9)

From the above, since the load value F (XT) at the position XT, which is the target position, is the load value F (ZT + DT), it is expressed by (Equation 10). Further, the load value F (XT) with respect to the position XT is shown in FIG.
F (XT) [N] = F (Z0 + R + DT)
= F (Z0) [N] + W (Z0) [N / mm] * R [mm]
+ W (Z0) [N / mm] * DT [mm]
(Equation 10)

In FIG. 6, the inclination between the position ZS and the position Z0 is the inclination value W0 [N / mm], and the inclination between the position Z0 and the position ZT is the inclination value W1 [N / mm], the inclination between the position ZT and the position XT. Is the load inclination value W2 [N / mm].

The change ΔF (Z0 → ZT) of the load between the position Z0 and the position ZT is as shown in (Equation 100).
ΔF (Z0 → ZT) [N] = W1 [N / mm] * R [mm]
(Equation 100)

Similarly, the change ΔF (ZT → XT) of the load between the position ZT and the position XT is as shown in (Equation 101).
ΔF (ZT → XT) [N] = W2 [N / mm] * DT [mm]
(Equation 101)

Therefore, F (XT) is as shown in (Equation 102).
F (XT) [N] = F (Z0) [N] + ΔF (Z0 → ZT) [N]
+ ΔF (ZT → XT) [N]
(Equation 102)

Substituting (Equation 100) and (Equation 101), (Equation 102) becomes as shown in (Equation 103).
F (XT) [N] = F (Z0) [N] + W1 [N / mm] * R [mm]
+ W2 [N / mm] * DT [mm]
(Equation 103)

Since the difference R [mm] and the insufficient movement distance DT [mm] are minute, the load inclination values W1 [N / mm] and W2 [N / mm] are based on the approximate expressions of (Equation 104) and (Equation 105). As shown.
W1 [N / mm] = W0 [N / mm]
(Equation 104)
W2 [N / mm] = W0 [N / mm]
(Equation 105)

Substituting (Equation 104) and (Equation 105), (Equation 103) becomes as shown in (Equation 106).
F (XT) [N] = F (Z0) [N] + W0 [N / mm] * R [mm]
+ W0 [N / mm] * DT [mm]
(Equation 106)

Since the load inclination value W0 [N / mm] is the load inclination value W1 [N / mm] at the position Z0 [mm], (Equation 106) becomes (Equation 10).
F (XT) [N] = F (Z0) [N] + W (Z0) [N / mm] * R [mm]
+ W (Z0) [N / mm] * DT [mm]
(Equation 10)

Since the insufficient movement distance DT is the amount of deflection at the position XT, which is the final target position, it is expressed by (Equation 11).
DT [mm] = K [mm / N] * F (XT) [N]
(Equation 11)

Substituting (Equation 10) into the right side of (Equation 11), the insufficient movement distance DT is expressed by (Equation 12).
DT [mm] = K [mm / N] * F (Z0) [N]
+ K [mm / N] * W (Z0) [N / mm] * R [mm]
+ K [mm / N] * W (Z0) [N / mm] * DT [mm]
(Equation 12)

・・・・・（式１３）
ここで、Ｆ（Ｚ０）［Ｎ］、Ｋ［ｍｍ／Ｎ］、Ｗ（Ｚ０）［Ｎ／ｍｍ］、ＳＶ［Ｓ］、Ｖ［ｍｍ／Ｓ］は、測定または算出により上記の通り既知であり、演算部２０は、（式１３）に基づき不足移動距離ＤＴの算出を行う。 Based on (Equation 12) and (Equation 6), the insufficient travel distance DT is expressed by (Equation 13).

(Equation 13)
Here, F (Z0) [N], K [mm / N], W (Z0) [N / mm], SV [S], and V [mm / S] are known as described above by measurement or calculation. Yes, the calculation unit 20 calculates the insufficient travel distance DT based on (Equation 13).

When the ram 31 reaches the position Z0, the calculation unit 20 calculates the insufficient movement distance DT, and transmits a movement command related to the insufficient movement distance DT to the command pulse generation unit 26. The position Z0 is a position before the ram 31 reaches the position ZT, which is a position satisfying the set movement distance DS. The position Z0 is separated from the position ZT by a distance corresponding to the difference R [mm].

When the ram 31 reaches the position Z0, the servomotor 42 has a "reservoir pulse" corresponding to the difference R [mm]. There is a time delay until the rotation of the servomotor 42 reaches the amount of rotation corresponding to the "accumulated pulse". In the time due to this delay, the calculation unit 20 calculates the insufficient movement distance DT before the ram 31 reaches the position ZT.

If the movement applied to the set movement distance DS and the insufficient movement distance DT is performed by stopping the ram 31 once, the load value F (Z0) applied to the ram 31 fluctuates greatly, so that the insufficient movement distance DT is accurately performed. Cannot make a calculation. The calculation unit 20 calculates the insufficient movement distance DT before the ram 31 reaches the position ZT, and moves the distance applied to the set movement distance DS and the insufficient movement distance DT without stopping the ram 31.

[Operation of the arithmetic unit 20 accompanied by deceleration of the ram 31]
The calculation unit 20 may decelerate or accelerate the movement of the insufficient movement distance DT without stopping the ram 31.

When the ram 31 is moved at a constant speed, the arithmetic unit 20 transmits a movement command to the command pulse generation unit 26 at regular time intervals, and the servomotor 42 is directly proportional to the number of pulses output from the command pulse generation unit 26. It rotates at the angle of rotation. For example, when the movement speed of the ram 31 is high, the calculation time of the insufficient movement distance DT is insufficient, and the calculation unit 20 delays the transmission of the movement command related to the insufficient movement distance DT to the command pulse generation unit 26, resulting in the ram. The movement of 31 may be stopped.

The load value F (Z0) differs depending on the moving speed of the ram 31. When the load value F (Z0) applied to the ram 31 is measured after decelerating the movement of the ram 31, the value of the load value F (Z0) fluctuates and the load value F (Z0) is detected accurately. I can't. As a result, the insufficient movement distance DT is not calculated accurately, which is not preferable. When it is predicted that the calculation time of the insufficient movement distance DT will be insufficient and it is necessary to reduce the movement speed of the ram 31, the calculation unit 20 will perform the insufficient movement distance DT before decelerating the movement of the ram 31. May be calculated.

Further, after the movement command is transmitted from the calculation unit 20, there is a time delay until the ram 31 completes the movement by the movement command. In particular, when the drive unit 4 is configured to include the servomotor 42, this time delay is unavoidable. For example, the time until the rotation amount of the servomotor 42 reaches the rotation amount corresponding to the "accumulated pulse" corresponds to this time delay. The separation distance between the position ZT, which is the target position to move by the set movement distance DS, and the position Z0 of the ram 31 at the time when the movement command is transmitted is the distance caused by the "accumulation pulse", and is the distance caused by the "accumulation pulse". It becomes the difference R shown in.

When the difference R is large, the distance between the position ZT which is the target position and the position Z0 of the ram 31 at the time when the movement command is transmitted becomes large, so that the insufficient movement distance DT is not calculated accurately, which is not preferable. The difference R is directly proportional to the moving speed V of the ram 31 as shown in (Equation 6). Therefore, by decelerating the moving speed V of the ram 31, the difference R can be reduced and the calculation accuracy of the insufficient moving distance DT can be improved. Even when the movement speed of the ram 31 is decelerated for the purpose of improving the calculation accuracy of the insufficient movement distance DT, the calculation unit 20 calculates the insufficient movement distance DT before decelerating the movement of the ram 31. May be good.

The calculation unit 20 detects the load value F (ZE) of the ram 31 with respect to the object W at the position ZE before the ram 31 reaches the position Z0 by the detection unit 5, and calculates the insufficient movement distance DT. The position ZE is a position separated from the base 8 by a moving distance Q [mm] from the position Z0. After that, the arithmetic unit 20 controls to decelerate the movement of the ram 31. In order to slow down the movement of the ram 31, the arithmetic unit 20 increases the time interval for transmitting the movement command to the command pulse generation unit 26.

As described above, when the movement of the ram 31 is decelerated at the position ZE, the insufficient movement distance DT is calculated by (Equation 14) instead of (Equation 10).
F (XT) [N] = F (ZE + Q + R + DT)
= F (ZE) [N] + W (ZE) [N / mm] * Q [mm]
W (ZE) [N / mm] * R [mm] + W (ZE) [N / mm] * DT [mm]
(Equation 14)
The moving distance Q [mm] is the distance between the position ZE and the position Z0.

・・・・・（式１５）
ここで、Ｆ（ＺＥ）［Ｎ］、Ｋ［ｍｍ／Ｎ］、Ｗ（ＺＥ）［Ｎ／ｍｍ］、Ｑ［ｍｍ］、ＳＶ［Ｓ］、Ｖ［ｍｍ／Ｓ］は、測定または算出により上記の通り既知であり、演算部２０は、（式１５）に基づき不足移動距離ＤＴの算出を行う。 Further, the insufficient movement distance DT is represented by (Equation 15) instead of (Equation 13).

(Equation 15)
Here, F (ZE) [N], K [mm / N], W (ZE) [N / mm], Q [mm], SV [S], and V [mm / S] are measured or calculated. As described above, the calculation unit 20 calculates the insufficient movement distance DT based on (Equation 15).

The arithmetic unit 20 of the control unit 2 performs an operation accompanied by deceleration of the movement of the ram 31 according to the program shown in FIG. 7 stored in the program storage unit 21.

First, the arithmetic unit 20 detects that the switch 231 of the operation unit 23 has been pressed and starts processing (step S11). At the start of the press operation, the operator presses the switch 231 supporting the start of the press operation.

Next, the calculation unit 20 reads out the position ZT stored in the parameter storage unit 25 (step S12). The position ZT determines the target stop position of the ram 31 at the end of the press. The position ZT is the position of the set movement distance DS in the direction of the base 8 from the position ZS. The set moving distance DS is the moving distance of the ram 31 assuming that the press device 1 does not bend.

Next, the calculation unit 20 transmits a movement command to the command pulse generation unit 26 (step S13). The calculation unit 20 moves the ram 31 from the position ZS to the position ZT which is the set movement distance DS by the movement command.

The servomotor 42 rotates at an angle of rotation that is directly proportional to the number of pulses output from the command pulse generation unit 26. The calculation unit 20 transmits a movement command corresponding to the set movement distance DS to the command pulse generation unit 26 in several orders.

Next, the calculation unit 20 determines whether the ram 31 has reached the position ZE (step S14). At the position ZE, the detection unit 5 detects the load value F (ZE) of the ram 31 with respect to the object W, calculates the insufficient movement distance DT, and controls the ram 31 to decelerate. The position ZE is a position before the ram 31 makes a movement related to the insufficient movement distance DT and before the movement related to the set movement distance DS is completed. The position of the ram 31 is determined based on the cumulative amount of rotation of the servomotor 42 accumulated and counted by the encoder position counter 28.

If it is not determined that the ram 31 has reached the position ZE, the arithmetic unit 20 repeats the operation of step S13. When it is determined that the ram 31 has reached the position ZE, the arithmetic unit 20 performs the operation of step S15.

When the ram 31 determines that the position ZE has been reached, the calculation unit 20 receives the load value F (ZE) at the position ZE (step S15). FIG. 8 shows a graph showing the relationship between the position of the ram 31 and the load value F (ZE).

Next, the calculation unit 20 calculates the load inclination value W (ZE) (step S16). The calculation of the load inclination value W (ZE) is performed by (Equation 4) based on the load value F (ZE) received in step S05. The load inclination value W (ZE) is the amount of change in the load value F (ZE) with respect to the moving distance of the ram 31. The load slope value W (ZE) corresponds to the differential value of the load value F (ZE) at the position ZE of the ram 31.

Next, the calculation unit 20 calculates the insufficient movement distance DT (step S17). The insufficient travel distance DT is calculated by the above (Equation 15).

Next, the calculation unit 20 transmits a movement command for the insufficient movement distance DT to the command pulse generation unit 26 (step S18). The servomotor 42 receives the movement command converted into a pulse from the command pulse generation unit 26. As a result, the servomotor 42 rotates, and the ram 31 moves over the insufficient movement distance DT.

The calculation unit 20 transmits a movement command to the command pulse generation unit 26 so as to decelerate and move the ram 31 (step S19). As a result, the ram 31 moves by decelerating the movement distance Q in the set movement distance DS. The calculation unit 20 may control the ram 31 to move at a speed before reaching the position ZE after the ram 31 decelerates the movement distance Q and moves.

As a result, the ram 31 is moved to position XT. The object W is pressed with the distance from the position XS to the position XT. The distance from position XS to position XT is equal to the desired press amount DP. As a result, the object W is pressed with a desired pressing amount DP.

After that, the calculation unit 20 stops the press operation.

The above is the operation of the press device 1.

[1-3. effect]
(1) According to the present invention, the press device 1 includes a ram 31 that applies a load to an object W to be pressed, a drive unit 4 that drives the ram 31, and a load of the load of the ram 31 on the object W. The detection unit 5 for detecting the value F (Z0) and the control unit 2 for controlling the drive unit 4 so that the ram 31 applies a load to the object W are provided, and the control unit 2 is based on a preset setting. Control is performed to move the ram 31 at a set movement distance DS in which the press amount when the object W is actually pressed is equal to or less than the desired press amount DP, and the desired movement distance DS is desired while the ram 31 is moving the set movement distance DS. The insufficient movement distance DT of the ram 31 that is insufficient with respect to the press amount DP is calculated based on the load value F (Z0) detected by the detection unit 5, and the ram 31 controls to move the insufficient movement distance DT. It is possible to provide a press device 1 capable of pressing an object W well.

Since the load value F (Z0) of the ram 31 is detected by the detection unit 5 while the ram 31 is moving the set movement distance DS, the load value F (Z0) of the load of the ram 31 is accurately detected. As a result, the insufficient movement distance DT is calculated with high accuracy, and as a result, the object W can be pressed with high accuracy.

(2) According to the present invention, the control unit 2 of the press device 1 controls to move the set movement distance DS and the insufficient movement distance DT without stopping the ram 31, so that the object W can be pressed accurately. It is possible to provide a press device 1 that can be used.

If the movement applied to the set movement distance DS and the insufficient movement distance DT is performed by stopping the ram 31 once, the load value F (Z0) applied to the ram 31 fluctuates greatly, so that the insufficient movement distance DT is accurately performed. Cannot make a calculation. According to the present invention, the control unit 2 moves the movements related to the set movement distance DS and the insufficient movement distance DT without stopping the ram 31, so that the fluctuation of the load value F (Z0) applied to the ram 31 is suppressed. be able to. As a result, the insufficient movement distance DT is calculated accurately. As a result, the object can be pressed with high accuracy regardless of the bending generated in the pressing device 1.

Further, when the ram 31 is stopped once, the press working result of the object W may be affected due to press fitting or the like. Further, when the ram 31 is stopped once, there is a drawback that the processing time per object W becomes longer than when the ram 31 is not stopped once. As a result, there is a drawback that the quantity of the object W that can be press-processed in a unit time is reduced.

According to the present invention, the control unit 2 moves the movement related to the set movement distance DS and the insufficient movement distance DT without stopping the ram 31, so that the press working result of the object W caused by press-fitting or the like can be obtained. The impact can be mitigated. Further, according to the present invention, the processing time per object W can be shortened as compared with the case where the ram 31 is not stopped once, and as a result, the object W that can be pressed in a unit time can be pressed. The quantity can be increased.

(3) According to the present invention, the control unit 2 is caused by the reaction force generated by the load applied by the ram 31 to the object W based on the load value F (Z0) detected by the detection unit 5. Since the bending amount δ applied to the bending is calculated and the insufficient movement distance DT is calculated based on the calculated bending amount δ, it is possible to provide the press device 1 capable of accurately pressing the object W.

The amount of deflection δ generated in the press device 1 may differ for each object W. Further, the rigidity of the members constituting the press device 1 may change due to secular variation or temperature change, and the deflection generated in the press device 1 may differ. The control unit 2 calculates the amount of deflection δ generated in the press device 1 based on the load value F (Z0) detected by the detection unit 5, and calculates the insufficient movement distance DT based on the amount of deflection δ.

According to the present invention, the control unit 2 calculates the deflection amount δ for each object W based on the load value F (Z0) detected by the detection unit 5, and the insufficient movement distance based on the calculated deflection amount δ. Since the DT is calculated, the object W can be pressed with high accuracy.

(4) According to the present invention, the control unit 2 calculates the insufficient movement distance DT based on the amount of change of the load value F (Z0) detected by the detection unit 5 with respect to the movement distance of the ram 31, so that the accuracy is correct. It is possible to provide a press device 1 capable of pressing an object W well.

The control unit 2 predicts the load value F (XT) at the position XT of the ram 31 at the time of press completion based on the amount of change in the load value F (Z0) with respect to the movement distance of the ram 31, and calculates the insufficient movement distance DT. conduct. As a result, the insufficient movement distance DT is calculated with high accuracy, and the object W can be pressed with high accuracy.

(5) According to the present invention, the control unit 2 detects the load value F (Z0) of the ram 31 with respect to the object W by the detection unit 5, calculates the insufficient movement distance DT, and then decelerates the ram 31. Since the control is performed to move the ram 31, it is possible to provide the press device 1 capable of accurately pressing the object W even when the moving speed of the ram 31 is high.

When the movement speed of the ram 31 is high, the calculation time of the insufficient movement distance DT is insufficient, and the calculation unit 20 delays the transmission of the movement command related to the insufficient movement distance DT to the command pulse generation unit 26, and as a result, the ram 31 The movement may stop.

The load value F (Z0) differs depending on the moving speed of the ram 31. When the load value F (Z0) applied to the ram 31 is measured after decelerating the movement of the ram 31, the value of the load value F (Z0) fluctuates and the load value F (Z0) is detected accurately. I can't. As a result, the insufficient movement distance DT is not calculated accurately, which is not preferable. When it is predicted that the calculation time of the insufficient movement distance DT will be insufficient and it is necessary to reduce the movement speed of the ram 31, the calculation unit 20 will perform the insufficient movement distance DT before decelerating the movement of the ram 31. Is calculated.

Further, after the movement command is transmitted from the calculation unit 20, there is a time delay until the ram 31 completes the movement by the movement command. In particular, when the drive unit 4 is configured to include the servomotor 42, this time delay is unavoidable. For example, the time until the rotation amount of the servomotor 42 reaches the rotation amount corresponding to the "accumulated pulse" corresponds to this time delay. The separation distance between the position ZT, which is the target position to move by the set movement distance DS, and the position Z0 of the ram 31 at the time when the movement command is transmitted is the distance caused by the "accumulation pulse", and is the distance caused by the "accumulation pulse". It becomes the difference R shown in.

When the difference R is large, the distance between the position ZT which is the target position and the position Z0 of the ram 31 at the time when the movement command is transmitted becomes large, so that the insufficient movement distance DT is not calculated accurately, which is not preferable. The difference R is directly proportional to the moving speed V of the ram 31 as shown in (Equation 6). Therefore, by decelerating the moving speed V of the ram 31, the difference R can be reduced and the calculation accuracy of the insufficient moving distance DT can be improved. Even when the movement speed of the ram 31 is decelerated for the purpose of improving the calculation accuracy of the insufficient movement distance DT, the calculation unit 20 calculates the insufficient movement distance DT before decelerating the movement of the ram 31. May be good.

As a result, the load value F (Z0) applied to the ram 31 is accurately measured, and the insufficient movement distance DT is calculated based on the measured load value F (Z0), so that the insufficient movement distance DT is calculated accurately. .. As a result, the object W can be pressed with high accuracy.

(6) According to the present invention, the control unit 2 transmits a movement command for the set movement distance DS to the drive unit 4, and then transmits a movement command for the insufficient movement distance DT. The rotation of the servomotor 42 is delayed in time until it reaches the rotation amount corresponding to the "accumulation pulse" in the movement command applied to the set movement distance DS. The control unit 2 calculates the insufficient movement distance DT in this delay time.

As a result, the control unit 2 can move the movement related to the set movement distance DS and the insufficient movement distance DT without stopping the ram 31. As a result, the load value F (Z0) applied to the ram 31 can be accurately detected without stopping the ram 31. As a result, the insufficient movement distance DT is calculated accurately. As a result, the object can be pressed with high accuracy.

[2. Other embodiments]
Although embodiments including modifications have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and variations thereof are included in the scope of the invention described in the claims and the equivalent scope thereof, as are included in the scope and gist of the invention. The following is an example.

(1) In the above embodiment, the calculation of the insufficient movement distance DT is performed once at the position Z0 during one press operation, but the calculation of the insufficient movement distance DT is performed once during one press operation. It may be done once. For example, the calculation unit 20 calculates the first shortage movement distance DT1 at the transmission position Z01 after transmitting the movement command related to the set movement distance DS to the command pulse generation unit 26, and the movement related to the shortage movement distance DT1. Even if the second insufficient movement distance DT2 is calculated at the transmission position Z02 after the command is transmitted to the command pulse generation unit 26, the movement command related to the insufficient movement distance DT2 is transmitted to the command pulse generation unit 26. good.

In this way, by calculating the insufficient movement distance DT a plurality of times during one press operation, even when the load value F (Z02) applied to the ram 31 changes due to the insufficient movement distance DT1, the load value F (Z02) is accurately calculated. The insufficient travel distance DT2 can be calculated. This makes it possible to provide the press device 1 capable of pressing the object W with high accuracy.

(2) In the above embodiment, the desired press amount DP is the difference distance between the position where the ram 31 abuts on the object W at the start of pressing and the processed position of the ram 31 after the ideal press is performed. It was supposed to be. However, the desired press amount DP is not limited to the moving distance of the ram 31. For example, the desired press amount DP may be a numerical value relating to the volume of the press portion or the like. The set moving distance DS is the moving distance of the ram 31 corresponding to the desired press amount DP, assuming that the press device 1 does not bend.

(3) In the above embodiment, the position ZT is set in advance, and the set movement distance DS is the distance that the ram 31 moves based on the position ZT stored in advance in the parameter storage unit 25. However, the set movement distance DS may be set in advance and stored in the parameter storage unit 25 in advance.

Further, the items that are preset and stored in the parameter storage unit 25 are not limited to the position ZT or the set movement distance DS. For example, in addition to the position ZT and the set movement distance DS, a desired press amount DP may be preset and stored in the parameter storage unit 25 in advance. Alternatively, at least one of the position ZT, the set movement distance DS, and the desired press amount DP may be preset and stored in the parameter storage unit 25 in advance.

(4) In the above embodiment, the set moving distance DS is assumed to be the moving distance of the ram 31 assuming that the pressing device 1 does not bend, corresponding to the desired pressing amount DP for pressing the object W. .. However, the set movement distance DS is not limited to the above. For the set moving distance DS, a distance is selected by the operator so that the press amount when the object W is actually pressed is equal to or less than the desired press amount DP, is set in advance, and is stored in the parameter storage unit 25 in advance. You may do so. The set movement distance DS may be selected by the operator as follows.

The set movement distance DS is preferably the same value as the movement distance of the ram 31 corresponding to the desired press amount DP, but when the ram 31 is moved by the set movement distance DS, the object to be actually pressed. It may be a value selected so that the press amount of W is equal to or less than the desired press amount DP. The desired press amount DP may be set separately from the position ZT or the set movement distance DS. The set movement distance DS may be a numerical value selected by the operator as follows.

When the moving distance of the ram 31 corresponding to the desired press amount DP is 100 mm and the bending amount δ is 2 mm, for example, 80 mm as the set moving distance DS is set in advance and stored in the parameter storage unit 25 in advance. You may do it. In this case, the control unit 2 adds 20 mm, which is the difference between the set movement distance DS of 80 mm and the movement distance of the ram 31 corresponding to the desired press amount DP, 100 mm, and 2 mm, which is the deflection amount δ. However, the insufficient movement distance DT may be calculated as 22 mm. With this configuration, even when the moving speed of the ram 31 is high, the moving distance for measuring the load value F (Z0) applied to the ram 31 in advance can be specified by the set moving distance DS. .. As a result, it is possible to provide the press device 1 capable of accurately pressing the object W even when the moving speed of the ram 31 is high.

Further, when the moving distance of the ram 31 corresponding to the desired press amount DP is 100 mm and the deflection amount δ is 2 mm, it is known in advance that the deflection amount δ with respect to the total number of the target W is 1 mm or more. The set movement distance DS of 101 mm may be preset and stored in the parameter storage unit 25 in advance. In this case, the control unit 2 has a difference between 1 mm, which is the difference between the set movement distance DS of 101 mm and the movement distance of the ram 31 corresponding to the desired press amount DP, 100 mm, and the difference of 2 mm, which is the deflection amount δ. May be calculated and the insufficient movement distance DT may be calculated as 1 mm. With this configuration, the moving distance for measuring the load value F (Z0) applied to the ram 31 in advance can be specified at a position close to the press completion by the set moving distance DS. As a result, the load value F (Z0) of the ram 31 is detected more accurately. As a result, it is possible to provide the press device 1 capable of pressing the object W with high accuracy.

As described above, the set moving distance DS is set in advance by a distance selected by the operator so that the pressing amount when the object W is actually pressed is equal to or less than the desired pressing amount DP, and the parameter storage unit. It may be stored in advance in 25.

1 ... Press device 2 ... Control unit 20 ... Calculation unit 21 ... Program storage unit 22 ... Display unit 23 ... Operation unit 231 ... Switch 232 ... Input circuit 24 ... Primary storage unit 25 ... Parameter storage unit 26 ... Command pulse generation unit 27 ... Servo motor driver 28 ... Encoder position counter 3 ... Pressurizing unit 31 ... Ram 31a ... Female thread portion 31b ... Distortion column 32 ... Ball screw 4 ... Drive section 41 ... Power transmission section 41a, 41b ... Pulley 41c ... Belt 42 ... Servo motor 43 ... Encoder 5 ... Detection unit 51 ... Strain gauge 52 ... Communication unit 8 ... Base 9 ... Housing 9a ... Encoder 9b ... Support 9c ... Cascade

Claims (6)

A ram that applies a load to the object to be pressed,
The drive unit that drives the ram and
A detection unit that detects the load value of the load of the ram on the object, and
A control unit that controls the drive unit so that the ram applies a load to the object is provided.
The control unit
Based on the preset setting, the ram is controlled to move at a set movement distance at which the press amount when the object is actually pressed is equal to or less than the desired press amount.
While the ram is moving the set movement distance, the insufficient movement distance of the ram, which is insufficient for the desired press amount, is calculated based on the load value detected by the detection unit.
The ram controls the movement of the insufficient movement distance.
Press equipment. The control unit controls to move the set movement distance and the insufficient movement distance without stopping the ram.
Press equipment. The control unit calculates and calculates the amount of deflection due to the reaction force generated by the load applied to the object by the ram, based on the load value detected by the detection unit. The insufficient movement distance is calculated based on the amount of bending.
The press device according to claim 1 or 2. The control unit calculates the insufficient movement distance based on the amount of change of the load value detected by the detection unit with respect to the movement distance of the ram.
The press device according to any one of claims 1 to 3. The control unit
After detecting the load value of the ram on the object by the detection unit and calculating the insufficient movement distance, control is performed to decelerate and move the ram.
The press device according to any one of claims 1 to 4. The control unit transmits a movement command for the set movement distance to the drive unit in several steps, and then transmits a movement command for the insufficient movement distance.
The press device according to any one of claims 1 to 5.

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