JP4810246B2 - Servo press - Google Patents

Description

  The present invention relates to a servo press that linearly moves a slide using a servo motor. In particular, the present invention relates to a highly safe servo press having an emergency stop inspection function.

  The servo press linearly moves a slide (ram) by using a motion conversion mechanism that converts a rotational motion of a servo motor such as an AC servo motor into a linear motion. In this servo press, the position and speed of the slide can be freely controlled, and the press pressure can be easily controlled. For this reason, it has been widely used in place of the mechanical type in recent years because it increases the forming accuracy of the pressed product and has high productivity.

In such a servo press, a mechanical brake and an electric brake are usually used for stopping the slide in an emergency. The mechanical brake applies, for example, a frictional resistance to the output shaft of the motor or the output shaft of the motion conversion mechanism to brake the coaxial rotation. There are mainly the following three types of electric brakes for servo presses.
A) A motor that brakes the motor by making the rotational energy of the servo motor electrical energy and then consuming it in electrical resistance (so-called dynamic brake).
B) Accumulation of rotational energy of the servo motor in the capacitor as electric energy (regenerative braking).
C) A combination of a) and b).

  Such a servo press is provided with an emergency stop button for the safety of the operator. When this emergency stop button is pressed, the mechanical brake and electric brake work and the slide descent stops even during work. At this time, since the slide has inertia, it cannot be stopped suddenly, and it takes some time to stop. For safety reasons, the emergency stop must be managed so that the slide stop condition satisfies a predetermined standard. The predetermined standard is, for example, that the maximum stop time and the inertia fall value are equal to or less than an allowable value (control value), and are defined in the press standard. Here, the maximum stop time (also referred to as stop time) is the time from when the emergency stop button is pressed until the slide actually stops, and the inertia fall value (also referred to as travel distance) is the emergency stop button. This is the moving distance of the slide from when is pressed until the slide stops.

FIG. 8 is a diagram for explaining an example of a method for defining the maximum stop time.
8A and 8B, a is a horizontal distance (mm) from the push button to the front surface of the slide, b is a vertical distance (mm) from the push button to the top surface of the bolster, and Hd is a die height (slide with the top surface of the bolster). The distance between the lower surfaces of (mm).
For example, in a two-hand operated servo press, as shown in FIG. 8 (A), it is stipulated that the maximum stop time satisfies the following formula (for example, “press worker safety must” (central labor accident) Prevention association)).
D (safety distance [mm]) = 1.6 [mm / ms] × maximum stop time [ms] <a + b + 1/3 · Hd.

  Furthermore, some servo presses are provided with a light-type safety device. The sensor of this device is provided between the operation unit and the working unit of the press device, and is activated when an operator's hand or the like enters the working unit from the front of the device and automatically performs an emergency stop. As shown in FIG. 8 (B), the distance (a) between the sensor optical axis and the slide front surface of this safety device is also required to be longer than the aforementioned 1.6 [mm / ms] × maximum stop time [ms]. Has been.

  By the way, the servo press degrades electric brakes and mechanical brakes after long-term use. It is estimated that the deterioration of the electric brake is mainly caused by deterioration of electric parts such as a capacitor, and the deterioration of the mechanical brake is caused by wear of the brake shoe or the sag of the presser spring. Due to such deterioration of the brake, the above-mentioned maximum stop distance and inertia fall value become longer, which causes a problem in safety management.

  Since it is very important for safety measures to stop the slide within the allowable range at the time of emergency stop, the servo press usually inspects the operation of the emergency stop button once a year (maximum stop distance and inertia) It is obliged to determine whether the fall value is within an acceptable range. This inspection work is usually inspected by an inspection organization brought in a dedicated inspection device and externally attached to the press device.

  However, since it is necessary to stop the machine during the inspection, it is necessary to adjust the manufacturing process, which is troublesome and troublesome.

  On the other hand, a press with a built-in mechanism capable of measuring the maximum stop time has also been proposed (see, for example, Patent Document 1). The mechanism described in this document measures the maximum stop time when the press operation is stopped suddenly, determines whether a sufficient safety distance is secured, and if not satisfied, gives a warning. It is something that is emitted.

JP-A-6-218597

  Since this press machine has a built-in mechanism for measuring the maximum stop time, there is no need to attach an inspection device at the time of inspection, and inspection can be performed relatively easily. However, in this press machine, when there is an abnormality in the emergency stop, it is not determined in which part the abnormality is specifically occurring, and it is difficult to obtain a subsequent countermeasure policy.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a servo press having a test function that can more accurately determine the braking performance at the time of emergency stop.

  A servo press according to an embodiment of the present invention includes: a servo motor; a motion conversion mechanism that transmits a rotational motion of the motor to convert it into a linear motion; a slide that is moved up and down by the mechanism; and rotational energy of the servo motor An electric brake that brakes the motor by converting the electric energy into electric energy to be consumed or stored, a frictional resistance type mechanical brake attached to the servomotor or the motion conversion mechanism, the servomotor, the motion conversion mechanism, or the slide A servo press comprising: an angle or position detection sensor attached to the control unit; and a control unit for controlling each unit, wherein the following brake performance test is performed as a series of operations; a) test start B) Lowering the slide at a predetermined speed, c) Emergency stop signal command, d) Electric brake and mechanical brake operation, e C) Measurement of the time from c) until the slide stops (stop time) and / or calculation of the travel distance (inertia drop value) from c) to the stop of the slide, f) Stop time and / or travel distance G) When it is determined to be defective in f), only the electric brake or the mechanical brake is operated and b) to e) are performed, and h) the stop time and / or the moving distance is determined for each brake. I) Determination result display.

  According to the present invention, since the servo press main body includes a sequence for performing a brake performance test, it is not necessary to request an emergency stop confirmation inspection from an inspection organization or the like, and the inspection can be performed according to the convenience of work. Further, there is no need to attach an inspection device. For this reason, it is easy to have the consciousness that an operator performs an inspection positively, an inspection can be performed when necessary, and safety increases. Furthermore, since the deterioration of the electric brake and the mechanical brake which are considered to be related to the emergency stop abnormality can be individually inspected, it is possible to make a policy for dealing with the abnormality.

  In the present invention, the steps g) and h) are performed only when the stop time or moving distance exceeds the first threshold value in f), and the stopping time or moving distance is the second threshold value in f). When it exceeds, it is preferable to perform the use stop display.

  According to the present invention, each brake is independently inspected only when both the stopping time or the moving distance exceeds the first threshold value. As a result, the inspection time can be shortened and the brake use frequency can be reduced. Further, when the second threshold value, which is larger than the first threshold value, is exceeded, by stopping the use, safety can be secured immediately, and repairs can be quickly dealt with.

  In the present invention, the position information (number of pulses) of the sensor at the time of issuing an emergency stop signal is sent to the control section, the position information (number of pulses) of the sensor at the time of slide stop is sent to the control section, The control unit can calculate the maximum slide stop time (or stop distance) from the number of pulses obtained by subtracting the number of pulses of the sensor at the time of slide stop from the number of pulses of the sensor at the time of issuing an emergency stop signal. .

  In this invention, it is preferable to provide the linear scale which detects the position (height) of the said slide.

  In this case, since the actual stop position of the slide is detected, the maximum stop time and moving distance can be known more accurately. In addition, if a linear scale having a high resolution (for example, about 0.001 mm) is used, it is possible to detect a shift in the slide stop position during normal operation of the press apparatus.

  In the present invention, it is preferable that the motion conversion mechanism includes a ball screw and a nut screwed to the ball screw, and an angle detection sensor is attached to the ball screw.

  In this case, since the stop position of the slide is detected from the rotation angle of the ball screw that moves the slide up and down, the maximum stop time and stop distance can be accurately detected.

  In the present invention, it is preferable that an angle detection sensor is attached to the shaft of the servo motor.

  In this case, the detection value of the angle detection sensor attached to the shaft of the servo motor is compared with the output value of the angle detection sensor attached to the ball screw or the detection value of the linear scale to detect the angle of the servo motor attachment. The detection performance of the sensor can be checked. The angle detection sensor with a servo motor may cause problems such as motor runaway due to the influence of noise or soft errors. Such an inconvenience may also occur in an angle detection sensor and a linear scale provided with a ball screw. However, the abnormality of each sensor can be grasped by comparing the two. For this reason, it is possible to prevent a situation where the motor runs away due to a malfunction of an encoder attached to the motor, and the safety is further enhanced.

  A servo press according to another aspect of the present invention includes: a servomotor; a motion conversion mechanism that converts rotational motion of the motor into linear motion; a slide that is lifted and lowered by the mechanism; and rotational energy of the servomotor. An electric brake that brakes the motor by converting it into electric energy for consumption or accumulation; a frictional resistance mechanical brake attached to the servomotor or motion conversion mechanism; and the servomotor, motion conversion mechanism or slide A servo press comprising an attached angle or position detection sensor and a control unit for controlling each part, wherein the motion conversion mechanism comprises a ball screw and a nut screwed to the ball screw, and the shaft of the servo motor And an angle detection sensor, and a sensor for detecting the rotation angle of the ball screw, or Characterized in that it comprises a linear scale for detecting the position of the serial sliding (height).

  According to the present invention, by comparing the detection value of the angle detection sensor attached to the shaft of the servo motor with the output value of the angle detection sensor attached to the ball screw or the detection value of the linear scale, the servo motor The detection performance of the attached angle detection sensor can be checked. For this reason, it is possible to prevent a situation where the motor runs away due to a malfunction of an encoder attached to the motor, and the safety is further enhanced.

  As is clear from the above description, according to the present invention, since the servo press is equipped with a brake performance test function at the time of emergency stop, an emergency stop inspection can be performed without externally attaching an inspection device. . In addition, since the performance of the electric brake and the mechanical brake can be inspected separately, it is easy to obtain a policy for dealing with abnormalities. Further, in the case where a ball screw angle detection sensor or a linear scale is externally attached in addition to the motor output shaft angle detection sensor, the detection performance of the motor angle detection sensor can be checked by comparing the detection values of both.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram schematically showing the overall configuration of the servo press according to the first embodiment of the present invention.
FIG. 2 is an example of a main part of the control circuit of the servo press of FIG.
As shown in FIG. 1, a servo motor 10 and a motion conversion mechanism 20 that receives the rotational motion of the motor 10 and converts it into linear motion are provided on the upper portion of the main body casing 3 of the servo press 1. As the servo motor 10, for example, an AC servo motor can be used. The drive current of the servo motor 10 is controlled by a servo amplifier 11 that is electrically connected to the motor 10.

  The motion conversion mechanism 20 includes a ball screw 23 into which a nut 21 is screwed (which can of course be converted into rotational motion / linear motion by a crank mechanism or the like). The ball screw 23 is supported by a bearing support 25 fixed to the main body 3 by a bearing 27. A pulley 29 is fixed to the upper part of the ball screw 23. The pulley 29 is rotationally transmitted via a pulley 31 fixed to the output shaft 10 a of the servo motor 10 and a belt 33. When the servo motor 10 is rotationally driven, the ball screw 23 is rotationally driven by the belt 33, and the nut 21 screwed to the screw 23 slides on the straight line in the vertical direction.

  A slide 40 that is guided up and down by a guide (not shown) is fixed to the nut 21 of the ball screw 23. An upper mold 43 is mounted and held on the lower surface of the slide 40.

A bolster 45 is disposed at a position facing the lower surface of the slide 40 at the bottom of the main casing 3. A lower die 47 is installed on the bolster 45.
In addition, an operation unit 50 in which a plurality of push buttons 51 such as two work push buttons operated by both hands and an emergency stop push button are arranged is provided at the lower portion of the main body casing 3. A light beam safety device (not shown) is attached between the operation unit 50 and the operating region of the slide 40.

The slide 40 is moved up and down by the rotation of the servo motor 10, and the workpiece is processed by the upper mold 43 held on the slide 40 and the lower mold 47 installed on the bolster 45.
Note that the upper and lower limits of the slide 40 are set by a mechanical stopper (not shown), and normally, the slide 40 moves up and down between the normal maximum position and the normal minimum position between both stoppers.

The servo press 1 is provided with a mechanical brake 13 and an electric brake 15 that brake the rotation of the servo motor 10 during an emergency stop.
The mechanical brake 13 is provided inside the motor 10. For example, the brake shoe is pressed against a rotating member connected to the output shaft 10 a of the servo motor 10 to generate a frictional resistance, and the output shaft 10 a is generated by this frictional resistance. There are things that brake the rotation of the.
The electric brake 15 includes a plurality of resistors and the like provided in the middle of a motor output line connecting the servo motor 10 and the servo amplifier 11. When a brake operation command is issued, the output line from the servo amplifier 11 to the motor 10 is cut off, and the output of the servo motor 10 is connected to the resistance of the electric brake 15. As a result, the rotational energy during the inertial rotation of the servo motor 10 is consumed in the resistance, and the rotational drive of the motor 10 is braked.
When the emergency stop button is pressed or the light safety device is activated, the mechanical brake 13 is activated after the electric brake 15 is activated.

  An encoder 19 is attached to the servo motor 10. The encoder 19 is a sensor that can detect the rotation angle of the output shaft 10 a of the servomotor 10. The encoder 19 may be an incremental encoder that can detect the rotation amount, rotation speed, and rotation direction of the servo motor 10, or may be an absolute encoder that can detect the absolute position of the rotation angle of the servo motor 10. Good.

The main part of the control circuit of the servo press of FIG. 1 will be described with reference to FIG.
In the figure, a control panel (control unit) 60, a servo motor 10 electrically connected to the control panel 60, a mechanical brake B, an encoder E, and a servo motor 10 connected to an input terminal of the servo motor 10 are connected. A servo amplifier 11 to be driven is illustrated.

  The control panel 60 controls the servo motor 60, the servo amplifier 11, the electric brake relay contact 17, and the R5 relay contact provided on the control panel 60. Therefore, the control panel 60 connected to the operation unit 50 shown in FIG. 1 as a whole has a CPU, a timer, a memory, a counter (not shown), a touch display, a numeric keypad, etc. An input device, a calculation device, a storage device, and a display device necessary for control are included. For example, a screen as shown in FIG. 3 (details will be described later) is displayed on the touch display. In addition, an input from each button 51 of the operation unit 50 in FIG. 1 and a value detected by the encoder 19 are also input to the control panel 60. The R5 relay contact in the control panel 60 invalidates the operation of the mechanical brake 13.

  Terminals L1, L2, and L3 connecting the control panel 60 and the servo amplifier 11 are for connecting power lines, and control instructions input to the control panel 60 from the push button 51 of the operation unit 50 or the touch display are controlled. It is converted into an electrical signal by the panel 60 and input to the servo amplifier 11, and a state necessary for the operation of the servo motor 10 and the servo amplifier is set.

The terminals U, V, and W connecting the servo motor 10 and the servo amplifier 11 mean the U phase, V phase, and W phase of the servo motor 10, respectively. Terminal E is grounded.
For example, when a permanent magnet is used for the rotor of the servo motor 10, in order to generate torque efficiently, the magnetic flux generated by the permanent magnet of the rotor and the U phase, V phase, and W phase of the servo motor 10 Since the vector sum of the currents flowing through the coils must be orthogonal, in order to connect between the servo motor 10 and the servo amplifier 11 that drives the servo motor 10, each phase on the servo motor 10 side and the servo It is necessary to connect the respective phases on the amplifier 11 side so as to correspond to each other.

  In the configuration as described above, the operation mode of the electric brake 15 of the servo amplifier 11 is set according to an instruction from the button 51 of the operation unit 50 or the touch display, and further, an operation of opening or shorting the R5 relay contact is performed. The mode can be set. As modes that are specifically set, for example, a normal operation mode, a stop performance A mode, and a stop performance B mode are assumed. Here, the normal operation mode is a mode in which the electric brake is enabled and the mechanical brake is enabled, and the stop performance A mode is a mode in which the electric brake is enabled and the mechanical brake is disabled. The B mode is a mode in which the electric brake is disabled and the mechanical brake is enabled.

  In the state of the mode set to any of the above, the electric brake relay contact 17 disposed in the servo amplifier 11 and the R5 relay contact provided in the control panel 60 are in a state in which an emergency stop is applied by operating the operation SW. In this case, the operation is as follows.

When the normal operation mode (both brakes enabled) is set, the 1st and 3rd terminals of the electric brake relay contact 17 and the 4th and 6th terminals are short-circuited, and the R5 relay contact Becomes a short circuit state.
In stop performance A mode (electric brake enabled mechanical brake disabled), terminals 1 and 3 of electric brake relay contact 17 and terminals 4 and 6 are short-circuited, and the R5 relay contact is open. It becomes a state.
In stop performance B mode (electric brake disabled mechanical brake enabled), terminals 1 and 2 of electric brake relay contact 17 and terminals 4 and 5 are short-circuited, and R5 relay contact is short-circuited. It becomes a state.

  In the circuit of FIG. 2, MC indicates an electromagnetic switch, P24B indicates DC 24V, and N24 indicates 0V. The analog input / output unit indicates a voltage / current output module, and the output unit indicates a sequencer output module.

Next, the operation during the brake performance deterioration test will be described.
3 and 4 are examples of displays showing the procedure of the brake performance inspection test.
FIG. 5 is a flowchart showing an example of the procedure of the brake performance inspection test.
FIG. 6 is a modification of the flowchart of FIG.

  In this test, when both the normal state mechanical brake 13 and the electric brake 15 are operated in advance, when only the normal state mechanical brake 13 is operated, only the normal state electric brake 15 is operated. When each is operated, the maximum stop time and the maximum stop distance are measured, and each value is stored in the memory of the control panel 60.

  Further, the maximum stop time and moving distance vary depending on the mass of the upper mold 43, and the stop time and distance become longer as the mass increases. Therefore, by measuring the maximum stop time and travel distance in each case (both brakes effective, only electric brakes effective, only mechanical brakes effective) when the mass of the upper mold 43 is changed in advance, the mass and the maximum stop time are measured. Alternatively, the relationship with the movement distance is grasped and stored in the memory of the control panel 60.

First, a basic brake performance inspection test procedure will be briefly described with reference to FIGS.
This operation can be performed in accordance with instructions on a touch-type display provided on the control panel 60. First, as shown in FIG. 3A, a mass input screen appears, and the mass of the upper mold is input from the numeric keypad. Then, as shown in FIG. 3B, a stop performance selection screen appears. Here, a normal operation mode (both brakes effective), stop performance A mode (electric brake effective mechanical brake disabled), and stop performance B mode (electric brake disabled mechanical brake enabled) can be selected.

  When selecting the normal operation mode, the normal operation SW on the display is touched. Then, the screen shown in FIG. 4A is displayed. Then, when the operation SW is touched, the electric brake relay contact 17 disposed in the servo amplifier 11 and the R5 relay contact provided in the control panel 60 operate as described above, and both brakes are activated, A performance inspection test is started.

When the stop performance A mode is selected, the display stop performance ASW is touched. Then, the screen shown in FIG. 4B is displayed. When the operation SW is touched, the electric brake relay contact 17 disposed in the servo amplifier 11 and the R5 relay contact provided in the control panel 60 operate as described above, and the electric brake is valid and the mechanical brake is invalid. After that, the brake performance inspection test is started.
Similarly, when selecting the stop performance B mode, the display stop performance BSW is touched. Then, the screen shown in FIG. 4C is displayed. When the operation SW is touched, the electric brake relay contact 17 disposed in the servo amplifier 11 and the R5 relay contact provided in the control panel 60 operate as described above, and the electric brake is invalid and the mechanical brake is valid. After that, the brake performance inspection test is started.

  Thus, it can set to each mode and can also test | inspect an emergency stop for every mode. However, during the brake performance inspection test, it is preferable to automatically perform a series of operations in the order of normal operation mode → stop performance A mode → stop performance B mode. In this case, the display as shown in FIG. 3 (B) and FIG. 4 does not appear. After inputting the upper mold mass in FIG. 3 (A), the normal operation mode, the stop performance A mode, and the stop performance B mode are followed in this order. Control is performed so as to automatically measure the slide stop time and stop distance and determine whether or not it is normal. Hereinafter, this process will be described.

Next, a standard brake performance inspection flow will be described with reference to FIG.
First, in S1, the upper mold mass is input from the numeric keypad (see FIG. 3A). The same mass is displayed on the display, and the stop time and moving distance in each mode corresponding to the input mass are called up. At the start of the test, the electric brake relay contact 17 and the R5 relay contact are operated during an emergency stop operation so that the normal operation mode (both brakes enabled) is set. Next, in S2, the slide is automatically lowered, lowered for a predetermined time, and then the emergency stop is automatically activated. At this time, the position information (number of pulses) of the encoder 19 when the emergency stop signal is input is read and sent from the servo amplifier 11 to the control panel 60. Since both brakes 13 and 15 are effective in this state, both brakes operate and the slide 40 stops. Even after the emergency stop signal is issued (after brake operation), the slide 40 continues to descend due to inertia and stops. That is, the motor 10 also stops rotating after a predetermined time. Then, the position information (number of pulses) of the encoder 19 when the motor 10 is stopped is read and sent from the servo amplifier 11 to the control panel 60. In S3, the maximum stop time and moving distance (inertia drop value) of the slide 40 are calculated from the difference between the number of pulses of the encoder 19 when the emergency stop signal is issued and the number of pulses of the encoder 19 when the motor is stopped.

  In S4, it is determined whether or not the maximum stop time is within a normal range when both brakes are operated (control range, for example, within 0.1 seconds. If within the normal range, both brakes operate without any problem. In S5, for example, “no abnormality” is displayed on the display.

  On the other hand, if the maximum stop time is not within the normal range in S4, it is determined that there is a problem with the emergency stop, that is, one or both brakes have deteriorated. Therefore, in S6, only the electric brake 13 is operated by operating the electric brake relay contact 17 and the R5 relay contact (see FIG. 2) so that the stop performance A mode (electric brake effective mechanical brake disabled) is set. . In S7, after the slide 40 is lowered for a predetermined time, the emergency stop is automatically activated, the position information (number of pulses) of the encoder 19 when the emergency stop signal is input is read, and the control board 60 is read from the servo amplifier 11. Send to. Then, the position information (number of pulses) of the encoder 19 when the electric brake 13 is activated and the slide 40 is stopped is read and sent from the servo amplifier 11 to the control panel 60. Next, in S8, the stop time of the slide 40 is calculated from the difference between the number of pulses of the encoder 19 when the emergency stop signal is issued and the number of pulses of the encoder 19 when the motor is stopped.

  In S9, it is determined whether or not the stop time when only the electric brake 15 is operated is within a normal range (for example, 0.12 seconds) of the stop time when only the normal electric brake is operated. If it is not within the normal range, it is determined that the electric brake 15 is not operating normally. In S10, for example, an alarm is generated and “electric brake operation failure” is displayed on the display.

  On the other hand, if the stop time is within the normal range in S9, it is determined that the mechanical brake 13 may be abnormal. Therefore, in S11, only the mechanical brake 13 is operated by operating the electric brake relay contact 17 and the R5 relay contact (see FIG. 2) so that the stop performance B mode (electric brake invalid mechanical brake valid) is set. . In S12, after the slide 40 is lowered for a predetermined time, the emergency stop is automatically activated, the position information (number of pulses) of the encoder 19 when the emergency stop signal is input is read, and the control board 60 is read from the servo amplifier 11. Send to. Further, the position information (number of pulses) of the encoder 19 when the mechanical brake 13 is activated and the slide 40 is stopped is read and sent from the servo amplifier 11 to the control panel 60. Next, in S13, the stop time of the slide 40 is calculated from the difference between the number of pulses of the encoder 19 when the emergency stop signal is issued and the number of pulses of the encoder 19 when the motor is stopped.

  In S14, it is determined whether or not the stop time when only the mechanical brake 13 is operated is within the normal range (for example, 0.15 seconds) of the stop time when only the normal mechanical brake is operated. If it is not within the normal range, it is determined that the mechanical brake 13 is not operating normally. In S15, for example, an alarm is generated and “mechanical brake operation failure” is displayed on the display.

  On the other hand, if the stop time is within the normal range in S14, it is determined that the mechanical brake 13 is operating normally. That is, both the mechanical brake 13 and the electric brake 15 are operating normally, but the maximum stop time at the time of emergency stop is larger than the normal range. For example, “other defects” is displayed in S16.

  In the flowchart of FIG. 5, when the stop time is not within the normal range in S9 in the stop performance A mode (electric brake effective mechanical brake disabled), the case of the electric brake failure as shown in S10 and the case of other failures However, the description of the process of selecting the electric brake failure and other failures will be omitted.

  As a result, for example, when it is determined that the electric brake is defective, the electric brake is inspected as a countermeasure, and if necessary, repair or replacement may be performed. For this reason, when the emergency stop is abnormal, it is not necessary to inspect the entire apparatus and the like can be dealt with promptly.

In this example, the following modifications can be made.
The encoder 19 can also be attached to the ball screw 23. In this case, since the position information of the slide 40 can be obtained from the rotation of the ball screw 23 which is relatively close to the actual driving of the slide 40, it is more accurate. This is particularly effective when the rotation of the motor 10 and the rotation of the ball screw 23 are not synchronized due to the elongation of the belt 33 and the wear of the pulleys 29 and 31.

  Furthermore, the normal range of the maximum stop time in each mode can be divided into a first threshold value and a second threshold value (> first threshold value). For example, the first threshold value is a relatively small value within the normal range, and the second threshold value is the maximum value within the normal range. Value.

The flow in this case will be described with reference to FIG. Here, step S4 in FIG. 5 will be described. The same control can be performed in steps S9 and S14.
First, in S41, it is determined whether or not the maximum stop time is greater than a first threshold value (for example, 0.08 seconds). If it is not larger than the first threshold value, it is determined that the maximum stop time is within the good range, and the process proceeds to the subsequent operation (S5). On the other hand, if the maximum stop time is greater than the first threshold value in S41, the process proceeds to S42 to determine whether or not the maximum stop time is greater than a second threshold value (for example, 0.1 seconds). If it is smaller than the second threshold value, it is determined that the maximum stop time is still within the good range but it is necessary to observe the deterioration of each individual brake, and the process proceeds to the subsequent operation (S6). On the other hand, if the maximum stop time is larger than the second threshold value in S42, it is determined that the normal range is exceeded, and continuous use is not preferable. Therefore, the process proceeds to S43, for example, “use stop”. indicate.

FIG. 7 is a diagram showing the configuration of the servo press according to the second embodiment of the present invention.
The servo press 1 ′ in this example is different from the servo press in FIG. 1 in the following points. In the servo press 1 ′ in this example, a linear scale 70 is installed on the side of the elevating orbit of the slide 40. This linear scale 70 can be used for monitoring the brake performance, for example, having a resolution of about 0.1 to 1 mm. In FIG. 7, parts having the same functions and effects as those in FIG. 1 are denoted by the same reference numerals as those in FIG.

  The brake performance deterioration test of this example can be performed in the same manner as the procedure shown in FIGS. The flowchart of this example is substantially the same as the flowchart of FIG. 5 except for steps S3 and S4, S8 and S9, and S13 and S14. Here, the steps of S3 and S4 will be described, but S8 and S9, and S13 and S14 perform the same operation.

  In S3, the position (height) of the slide 40 is read by the linear scale 70 together with the number of pulses of the encoder 19 when the emergency stop signal is issued, and the position information is sent to the control unit 60. Then, the pulse number of the encoder 19 when the brake is activated and the slide 40 is stopped and the position where the slide 40 is stopped are read by the linear scale 70, and the position information is sent to the control unit 60. In S 4, the maximum stop time and the movement distance are calculated from the difference in the number of pulses of the encoder 19, and the slide movement distance is calculated from the difference in the position information of the linear scale 70.

  Here, the movement distance obtained by converting the maximum stop time obtained from the number of pulses of the encoder 19 and the movement distance obtained from the position information of the linear scale 70 are usually the same, but the actual slide 40 The value detected by the linear scale 70 for measuring the position is prioritized. If the difference between the two movement distances is large, there may be a problem with the encoder 19, so the encoder 19 needs to be inspected.

  If the resolution of the linear scale 70 is increased to about 0.001 mm, it is possible to detect the overrun of the slide 40 during normal operation of the press, and it can be used for slide position control feedback.

Next, a servo press according to another aspect of the present invention will be described with reference to FIG.
The servo press of this example has an operation check performance of the encoder 19 with a motor. The encoder 19 may cause problems such as motor runaway due to the influence of noise or soft errors. Therefore, as shown in FIG. 7, in addition to the encoder 19 that detects the rotation angle of the servo motor 10, an encoder 71 that detects the rotation angle of the ball screw 23, or a linear scale that detects the position (height) of the slide 40. 70 is externally attached.

  In the servo press of this aspect, for example, the slide stop position during normal operation is detected by the encoder 19 with the motor and also detected by the encoder 71 with the ball screw or the linear scale 70. Then, the value detected by the encoder 19 is compared with the value detected by the encoder 71 or the linear scale 70 with a ball screw. If the difference between the two is within the allowable range, it is determined that the encoder 19 is operating normally.

  On the other hand, if the difference between the two is outside the allowable range, it is determined that the encoder 19 is abnormal. Then, measures are taken to repair or replace the encoder 19. Further, the servo motor can be controlled based on the value measured by the encoder 71 or the linear scale 70 provided with a ball screw.

It is a figure showing typically the whole servo press composition concerning a 1st embodiment of the present invention. It is an example of the principal part of the control circuit of the servo press of FIG. It is an example of the display which shows the procedure of a brake performance inspection test. It is an example of the display which shows the procedure of a brake performance inspection test. It is a flowchart which shows an example of the procedure of a brake performance test. It is a modification of the flowchart of FIG. It is a figure which shows the structure of the servo press which concerns on the 2nd Embodiment of this invention. It is a figure for demonstrating an example of the method which prescribes | regulates the maximum stop time.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Servo press 3 Main body 10 Servo motor 10a Output shaft 11 Servo amplifier 13 Mechanical brake 15 Electric brake 17 Electric brake relay contact 19 Encoder 20 Motion conversion mechanism 21 Nut 23 Ball screw 25 Bearing support 27 Bearing 29 Pulley 31 Pulley 33 Belt 40 Slide 43 Top Type 45 Bolster 47 Lower type 50 Operation part 51 Push button 60 Control part (control panel)

Claims (6)

A servo motor,
A motion conversion mechanism that converts the rotational motion of the motor into linear motion, and
A slide raised and lowered by the mechanism;
An electric brake that brakes the motor by converting or accelerating or storing the rotational energy of the servomotor into electric energy;
A friction resistance mechanical brake attached to the servo motor or the motion conversion mechanism;
An angle or position detection sensor attached to the servo motor, motion conversion mechanism or slide;
A control unit for controlling each unit;
A servo press comprising:
Servo press characterized by performing the following brake performance tests as a series of operations;
a) Start of test,
b) Descent the slide at a predetermined speed,
c) Emergency stop signal command,
d) Electric brake and mechanical brake operation,
e) Measurement of the time from c) until the slide stops (stop time) and / or calculation of the movement distance (inertia fall value) from c) until the slide stops;
f) Pass / fail judgment of stop time and / or travel distance,
g) When it is determined to be defective in f), only the electric brake or the mechanical brake is operated, and b) to e) are performed.
h) Pass / fail judgment of stop time and / or travel distance for each brake,
i) Determination result display. Perform g) and h) only when the stop time or moving distance exceeds the first threshold in f).
2. The servo press according to claim 1, wherein when the stop time or moving distance exceeds the second threshold value in step f), the use stop display is performed. Sends position information (number of pulses) of the sensor at the time of issuing an emergency stop signal to the control unit,
Sends the position information (number of pulses) of the sensor when the slide stops to the control unit,
The control unit calculates the maximum slide stop time (or stop distance) from the number of pulses obtained by subtracting the number of pulses of the sensor at the time of slide stop from the number of pulses of the sensor at the time of issuing an emergency stop signal. The servo press according to claim 1 or 2.   The servo press according to any one of claims 1 to 3, further comprising a linear scale that detects a position (height) of the slide. The motion conversion mechanism includes a ball screw and a nut screwed into the ball screw,
The servo press according to any one of claims 1 to 4, wherein an angle detection sensor is attached to the ball screw.   6. The servo press according to claim 4, further comprising an angle detection sensor attached to the shaft of the servo motor.

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