JP2003260597A - Method of avoiding thermal displacement of electrically- driven survo press and thermal displacement avoidance device of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method which enables the easy suppression of a change in die height, dispensing with a sophisticated high-priced thermal displacement compensation device in an electrically-driven survo press and provide the device of the same. <P>SOLUTION: In the thermal displacement avoidance device of the electrically- driven survo press where the rotational power of a survo motor (2) is converted into the reciprocating motion of a slide (4) through a mechanical power transmission means, a partition wall (3) is provided between the survo motor (2) and at least any of the slide (4), a slide position sensor (5), an auxiliary frame (6) and a side frame (7). A suction means (20) for sucking a hot air attributable to the heat generated by the survo motor (2) may be provided above in the vicinity of an output axis of the servo motor (2). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for avoiding thermal displacement and a device for avoiding thermal displacement thereof, which enables highly accurate press working of an electric servo press.

[0002]

2. Description of the Related Art In recent years, in small and medium-sized press working, the demand for high precision and high speed has promoted the development of an electric servo press, and the progress of the electric servo press has been remarkable. Usually, a press machine has a slide that can move up and down, and is configured to perform press work between an upper die attached to this slide and a lower die installed on a bolster (or bed). However, in the case of the electric servo press, the distance from the upper surface of the bolster to the lower surface of the slide is to perform the desired high-precision pressing.
It is necessary to control the so-called die height displacement particularly strictly. Recently, the demand for high-precision machining of electric servo presses has been rapidly increasing, and in some cases, the slide position precision requirement of several microns has been reached.

The displacement of the die height is mainly caused by elastic displacement of the press bed, side frame, slide, slide drive system structure, etc., which is caused by the pressure load on the work. The main displacement of the press is the thermal displacement of the press bed, side frame, slides and slide drive system structures, etc., which occurs due to changes in the environmental temperature, heat generated by the drive motor during processing, or frictional heat in each part of the press drive. Can be raised.

Accurate management and maintenance of the die height is one of the most important matters for obtaining a highly accurate pressed product. Conventionally, the former press, which is a main factor of displacement of the die height, is used. Various methods and devices have been proposed to cope with the elastic displacement of each part so that the processing accuracy is not affected even when the press is elastically displaced. For example, in Japanese Utility Model Publication No. 3-41916, sensors for detecting the bending of the ram guide in the front-rear direction are provided on the left and right support frames provided close to the both side frames, and the sensors are detected based on the detected values by the sensors. A ram guide adjusting device for a press working machine has been proposed, which enables accurate press working by adjusting the ram guide back and forth.

On the other hand, the thermal displacement of the press, which is the main cause of the displacement of the die height amount described above, is
It is generated by thermal expansion of each part of the press due to the influence of temperature. Therefore, various methods and devices have been proposed to prevent the die height amount from being affected by temperature. For example, in Japanese Utility Model Laid-Open No. 2-1599, a temperature sensor for detecting the temperature of the press machine is provided, and the bottom dead center change of the slide corresponding to the temperature detected by this temperature sensor and the temperature of the press machine stored in advance. There is proposed a bottom dead center position correction device that calculates the bottom dead center position correction amount corresponding to the temperature signal from the temperature sensor and controls the slide drive motor based on this calculation result. There is. Further, in Japanese Patent Laid-Open No. 4-190921, thermal displacement is detected from temperature changes of the frame, the upper and lower tables, and the upper and lower molds.
A correction method has been proposed in which the distance between molds of an upper mold and a lower mold is corrected to a preset set value based on the obtained detection value.

Further, the above-mentioned elastic displacement of the press caused by the pressure load on the work and the thermal displacement of the press caused by the thermal expansion of each part of the press due to the influence of temperature during the press working are simultaneously solved. Japanese Patent Laid-Open No. 9-314395 can be cited as a conventional technique. The contents of the technology described in this publication will be described with reference to FIGS.
FIG. 5 is a side view of a C-frame press provided with a die height correction device according to an embodiment of the prior art,
FIG. 6 is a front view of a straight side press provided with a die height correction device according to an embodiment of the prior art. As shown in these drawings, in a press in which a slide 103 that is vertically movable by a slide driving means 102 is provided on the upper part of the press body 101,
An auxiliary frame 105 having a lower end side pivotally attached to the press body 101 and an upper end side having a free end is provided on one side surface of the auxiliary frame 105, and the slide position detecting means 108 and the temperature detection are provided on the free end side of the auxiliary frame 105. Means 110 and temperature detecting means 111 are provided in the slide position detecting means 108 to detect the position of the slide 103, the temperature of the auxiliary frame 105, and the temperature of the slide position detecting means 108, and to detect the slide position detecting means 108. The vertical movement of the slide 103 is NC controlled by the detected value detected by the temperature sensor, and the temperature of the auxiliary frame 105 detected by one temperature detection means 110 and the temperature of the slide position detection means 108 detected by the other temperature detection means 111, The extension of the auxiliary frame 105 is based on the temperature change amount obtained from the temperature difference from the preset reference temperature. The amount and the slide position detection means 10
8 has been disclosed. A technique of a die height correction device is disclosed in which the drift amount of 8 is calculated, and the obtained value is added to or subtracted from the command value of the NC control to correct the command value.

With this configuration, the vertical movement of the slide is controlled by the NC device based on the slide position detection value detected by the slide position detecting means, the temperature of the auxiliary frame supporting the slide position detecting means, and the slide position detecting means. Temperature of the auxiliary frame and the amount of drift of the slide position detecting means are calculated by the temperature detecting means, and the obtained values are added to the command value of the NC device for controlling the vertical movement of the slide. Since the command value is corrected by doing so, even if the air temperature or the temperature of the press body changes during press working, the die height does not change due to this, so highly accurate press working is possible. I am trying.

[0008]

As described above, maintaining and maintaining the die height with high accuracy is one of the most important items for obtaining a pressed product with high accuracy. It is necessary to solve both the elastic displacement of the above and the thermal displacement of the press at the same time, and the technique of Japanese Patent Laid-Open No. 9-314395 was introduced as the conventional technique.
However, this technique adopts an auxiliary frame that is not affected by the displacement of the main body frame due to the pressure reaction force at the time of press molding, and the slide position detecting means and the temperature detecting means are also attached to this auxiliary frame, and the slide position detecting means. A temperature detecting means is provided to detect the position of the slide, the temperature of the auxiliary frame, and the temperature of the slide position detecting means, and the vertical movement of the slide is NC controlled by the detection value detected by the slide position detecting means. Based on the temperature change amount obtained from the temperature difference between the auxiliary frame temperature detected by one temperature detection means, the slide position detection means detected by the other temperature detection means, and a preset reference temperature, The amount of expansion and contraction of the frame and the amount of drift of the slide position detecting means are calculated, and the obtained value is added to or subtracted from the command value of the NC control to obtain the finger value. It is that performs die height correction so as to correct the values. Therefore, although the die height correction control of the above-mentioned prior art has a good die height correction accuracy, the device for performing die height correction according to the amount of temperature change is very complicated, and this control device is costly. At the time of correction, the die height correction formula must be set for each machine,
This requires special know-how and not only requires skill, but also takes a lot of time and trouble to set it.

The present invention has been made in view of the above problems, and in an electric servo press for converting the rotational power of a servomotor into a reciprocating motion of a slide through a mechanical power transmission means, a complicated and expensive thermal displacement is caused. An object of the present invention is to provide a thermal displacement avoiding method and an avoiding device thereof that can easily suppress a change in die height without using a correction device.

[0010]

In order to achieve the above-mentioned object of the present invention, the first aspect of the present invention uses the rotational power of a servomotor to reciprocate a slide through a mechanical power transmission means. In a method for avoiding thermal displacement of an electric servo press that suppresses a change in die height due to thermal displacement of each portion of the electric servo press to be converted, the servo motor, the slide, a slide position sensor, an auxiliary frame having the slide position sensor attached, And a partition wall is provided between the slide frame and at least one of the side frames that support the slide so that the slide motor can be lifted and lowered. I tried to prevent it from being transmitted to at least one of them.

In the first aspect of the invention, the partition wall provided between the servo motor and at least one of the slide, the slide position sensor, the auxiliary frame and the side frame has a great influence on the die height displacement of the electric servo press. The heat generated by the servo motor, which is the largest factor of the thermal displacement, is blocked so as not to be transmitted to at least one of the slide, the slide position sensor, the auxiliary frame, and the side frame by direct or convection heat. Further, it is possible to prevent thermal displacement of the auxiliary frame or the like, or temperature drift due to heat of the slide position sensor. Therefore, without using a complicated and expensive thermal displacement correction device, it is possible to easily suppress the change of the die height by a very simple method of shutting off the heat by the partition wall, which is an excellent effect. Also, from this extremely simple configuration,
This device can be manufactured at low cost. Moreover, as in the prior art, when performing die height correction for each machine, it is troublesome to set the die height correction calculation formula, and it takes time to set the die height correction calculation formula, and the operation rate of the press decreases. The fear of is gone. Moreover, the special know-how required when setting the die height correction arithmetic expression is unnecessary, and the skill of know-how acquisition is not required.

A second aspect of the present invention is an electric servo press for converting rotational power of a servo motor into reciprocating motion of a slide through a mechanical power transmission means, wherein the servo motor is used.
Direct or convection of heat generated by the servo motor between at least one of the slide, the slide position sensor, the auxiliary frame to which the slide position sensor is attached, and the side frame that supports the slide so as to move up and down. A thermal displacement avoidance device for an electric servo press, characterized in that a partition for preventing conduction is provided to suppress a change in die height due to thermal displacement of each part of a slide, a slide position sensor, an auxiliary frame and a side frame. It is configured.

According to the second invention, since the partition wall is provided between the servo motor and at least one of the slide, the slide position sensor, the auxiliary frame and the side frame, the same effect as the first invention can be obtained. can get.

In a third aspect of the present invention, an electric servo press according to the second aspect of the present invention is characterized in that suction means for sucking warm air generated by heat generated by the servo motor is provided near the output shaft of the servo motor. The thermal displacement avoidance device of FIG.

According to the third aspect of the invention, since the suction means is provided near the output shaft side (for example, the motor pulley) of the servo motor, the servo is normally pushed up by the cooling fan attached to the lower part of the servo motor in the axial direction. The hot air generated by the heat generated by the motor is sucked by the suction means from above the servo motor, and the so-called push-pull type exhaust flow, which is generally considered to have excellent exhaust efficiency in terms of fluid dynamics, causes the servo motor to flow. Is generated in the outer peripheral portion of the servo motor, and the servo motor is efficiently cooled. And, in combination with the effect of the partition wall described in the second aspect, adverse effects such as thermal displacement of slides, side frames, auxiliary frames, and drift due to heat of the slide position sensor are suppressed as much as possible.
It is possible to obtain an effect that a change in die height can be suppressed to the extent that highly accurate press working can be performed without using a complicated and expensive thermal displacement correction device.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to FIGS. 1, 2 and 3. 1 is a side view of the inside of the electric servo press according to the present invention, FIG. 2 is an operation explanatory view of a thermal displacement avoidance device according to the present invention, and FIG. FIG.

As shown in FIG. 1, the servo press according to this embodiment includes side frames 7 arranged on both sides, a bed 9 and a bolster 8 arranged on the lower side, and a crown 10 arranged on the upper side. A slide 4 is provided at a position above the inside of the provided straight-side press body 1 so as to face the bolster 8 and above the bolster 8 so that the slide 4 can be moved up and down by the drive of a slide driving means 11. The slide driving means 11 moves the slide 4 up and down and applies a pressing force to a work (not shown), and a timing belt 12 that transmits rotational power of the servo motor 2.
And a motor pulley 13a and a screw shaft pulley 13 for transmitting the rotational power of the servo motor 2 and decelerating the rotation thereof.
b, a ball screw 14 and a nut 16 for converting rotational movement into vertical movement, and slide supporting means 15 for supporting a slide load. Servo motor 2 is press body 1
In order to keep the overall height of the crown low, the output shaft is arranged at the rear of the crown 10 with the posture facing upward. And
A protective cover 17 is provided at the rear of the servo motor 2 in the front-rear direction of the press in order to ensure safety in the rotating portion of the servo motor 2 and to provide the appearance of the press.

Further, in the present invention, as described above in the section of the prior art, in order to improve the positioning accuracy of the press by avoiding adverse effects of thermal displacement and elastic displacement of each part of the press, one side surface of the press main body 1 is provided. It is composed of an auxiliary frame 6 whose lower end is pivotally attached to the press body 1 and whose upper end is a free end, a sensor 5a attached to the side surface of the slide 4 and a linear sensor 5b provided on the upper end of the auxiliary frame 6. The slide position sensor 5 is provided. Further, in the present invention, since the die height displacement is controlled to the minimum and the position of the slide 4 is controlled, the position between the servo motor 2 and at least one of the slide 4, the slide position sensor 5, the auxiliary frame 6 and the side frame 7 is increased. A partition 3 is provided.
In this embodiment, the partition wall 3 partitions the servo motor 2 from all of the slide 4, the slide position sensor 5, the auxiliary frame 6, and the side frame 7.

Next, the operation of the present invention having the above construction will be described with reference to FIG.
3 and FIG. In an electric servo press that requires high-precision machining, even if a slight adverse effect of heat generation is not negligible, the press has an original function of pressurizing the work, and all of this work is performed by the servo motor 2. No matter how efficient the servo motor 2 is, the amount of heat generated is great, and the adverse effect on the thermal displacement of each part of the press is immeasurable.
In the present invention, as shown in FIG. 2, a partition wall 3 is provided between the servo motor 2 and at least one of the slide 4, the slide position sensor 5, the auxiliary frame 6 and the side frame 7.
However, in the conventional electric servo press, as shown in FIG. 3, the partition wall 3 was not provided between the servo motor 2 and each part of the press. Therefore, the heat generated by the servo motor 2 is conducted to the air around the servo motor 2,
It was agitated by a cooling fan provided at the rear portion of the servomotor 2 in the axial direction, and was conducted to each part of the press directly or by convection.

According to the results of the research conducted by the present inventors,
In the conventional electric servo press having the structure in which the partition wall 3 is not provided between the servo motor 2 and each part of the press (see FIG. 3), the temperature rise value (temperature rise) of each part of the press
When the electric servo press is operated without load for 4 hours in a room with a constant temperature environment of 28.1 ° C, for example,
In the auxiliary frame 6, t1 = 7.6 ° C., slide 4
At t2 = 2.2 ° C., at the servo motor 2 t
3 = 47.9 ° C., and as a result, the die height change in this case was +10 μ. However,
In the electric servo press of the present invention in which the partition wall 3 is provided between the servo motor 2 and each part of the press (see FIG. 2), the electric servo press is operated in a room having a constant temperature environment of 28.7 ° C. When operated without load for 4 hours, the temperature rise value (temperature rise) of each part of the press was increased to t3 = 53.0 ° C in the servo motor 2, but the auxiliary frame 6 was used. At t1 = 2.
At slide temperature of 7 ° C., t2 was drastically reduced to 1.8 ° C. in slide 4, and as a result, the die height change in this case was −3 μ, which was a very good result.

As shown in FIG. 2, the good result of the present invention is that the partition wall 3 blocks the servo motor 2 from the slide 4, the slide position sensor 5, the auxiliary frame 6, the side frame 7, and other parts of the press. In addition, the hot air generated by the heat generated in the servo motor 2 being conducted to the air around the servo motor is generated in the space surrounded by the partition wall 3, the side frame 7, and the protective cover 17 in the servo motor. It is considered that this is because the cooling fan in the lower part of 2 rectifies the gas upward and efficiently discharges it, and the heat is not transferred to each part of the press directly or by convection heat as in the conventional example.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a side view of the inside of the electric servo press according to the second embodiment. The same components as those in FIG. 1 are designated by the same reference numerals. In FIG.
The servo motor 2 is provided near the upper portion of the power transmission means (here, the motor pulley 13a) provided on the output shaft of the servo motor 2.
Suction means 20 (for example, an electric fan, a turbo fan, etc.) for sucking the warm air due to the heat generation is provided. According to this structure, since the suction means 20 is provided in the vicinity of the upper side of the output shaft of the servo motor 2, the warm air generated by the heat generated by the servo motor 2 and pushed up by the cooling fan in the axial lower part of the servo motor 2 is Since the suction means 20 sucks from above the servo motor 2, the flow of exhaust gas by a so-called push-pull method, which is generally considered to have very good exhaust efficiency in terms of fluid dynamics, is generated in the outer peripheral portion (heat generating portion) of the servo motor 2. ) Occurs, the servo motor 2 is efficiently cooled. And, in combination with the installation effect of the partition wall 2,
Since the adverse effects such as the thermal displacement of the slide 4, the side frame 7 and the auxiliary frame 6 and the temperature drift due to the heat of the slide position sensor 5 are suppressed as much as possible, the die height can be reduced without using a complicated and expensive thermal displacement correction device. It is possible to obtain the effect of suppressing the change in the number of times to the extent that highly accurate press working is possible.

According to this embodiment, the following actions and effects can be obtained. According to the present invention, in an electric servo press, a servo motor, a slide, a slide position sensor,
A partition wall is provided between at least one of the auxiliary frame and the side frame, which greatly affects the die height displacement of the electric servo press, and the heat generation of the servo motor, which is the largest factor of thermal displacement, is directly or The method or device was set so as not to be transmitted to each part inside the press by convection. Therefore, adverse effects such as thermal displacement of slides, side frames, auxiliary frames, and temperature drift due to heat of the slide position sensor do not occur. Therefore, it is possible to easily suppress the change in die height by a very simple method or device using a partition without using a complicated and expensive thermal displacement correction device. Further, since the configuration is extremely simple as described above, this device can be manufactured at low cost. Moreover, as in the prior art, when performing die height correction for each machine, it is troublesome to set the die height correction calculation formula, and it takes time to set the die height correction calculation formula, and the operating rate of the press decreases. The fear of is gone. Moreover, the special know-how required when setting the die height correction calculation formula is unnecessary, and the skill of know-how acquisition is not necessary.

Further, according to the present invention, in the electric servo press, since the suction means is provided near the output shaft of the servo motor, the warm air generated by the heat generated by the servo motor pushed up by the cooling fan under the servo motor is provided. Is sucked by the suction means from above the servo motor, and a push-pull exhaust flow is generated in the outer peripheral portion of the servo motor, so that the servo motor is cooled very efficiently. Then, in combination with the effect of the partition wall, thermal displacement of slides, side frames, auxiliary frames, and the like, and adverse effects due to heat of the slide position sensor are suppressed as much as possible, without using a complicated and expensive thermal displacement correction device. It is possible to obtain the effect that the change can be suppressed to the extent that highly accurate press working is possible.

[Brief description of drawings]

FIG. 1 is a side view of the inside of an electric servo press according to the present invention.

FIG. 2 is an operation explanatory view of the thermal displacement avoidance device according to the present invention.

FIG. 3 is an explanatory diagram of generation of thermal displacement according to the related art.

FIG. 4 is a side view of the inside of the electric servo press according to the second embodiment of the present invention.

FIG. 5 is a side view of a C-frame press provided with a die height correction device according to an embodiment of the related art.

FIG. 6 is a front view of a straight side press provided with a die height correction device according to an embodiment of the related art.

[Explanation of symbols]

1 ... Press body, 2 ... Servo motor, 3 ... Partition wall, 4 ... Slide, 5 ... Slide position sensor, 5a ... Sensor, 5b
... linear sensor, 6 ... auxiliary frame, 7 ... side frame, 8 ... bolster, 9 ... bed, 10 ... crown, 11
... Slide driving means, 12 ... Timing belt, 13a
... motor pulley, 13b ... screw shaft pulley, 14 ... ball screw, 15 ... slide supporting means, 16 ... nut, 17 ...
Protective cover, 20 ... suction means, 101 ... press body, 1
02 ... Slide driving means, 103 ... Slide, 105 ...
Auxiliary frame 108 ... Slide position detecting means 110
... temperature detecting means, 111 ... temperature detecting means.

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 4E088 AA01 AB04 EA10 GA10 JJ02                       JJ04                 4E090 AA01 AB01 BA02 CC04 HA01

Claims (3)

[Claims] 1. An electric motor that suppresses a change in die height due to thermal displacement of each part of an electric servo press that converts rotational power of a servo motor (2) into reciprocating motion of a slide (4) via a mechanical power transmission means. In a method for avoiding thermal displacement of a servo press, the servo motor (2), the slide (4), a slide position sensor (5), an auxiliary frame (6) with the slide position sensor (5) attached, and the slide ( By providing a partition wall (3) between at least one of the side frames (7) that supports the vertical movement of (4), the heat generated by the servo motor (2) slides (4) by direct or convection heat. ), A slide position sensor (5), an auxiliary frame (6), and / or a side frame (7) so that they are not transmitted to the thermal displacement avoiding method of the electric servo press. 2. An electric servo press for converting rotational power of a servo motor (2) into reciprocating motion of a slide (4) via a mechanical power transmission means, the servo motor (2) and the slide (4). ), A slide position sensor (5), an auxiliary frame (6) to which the slide position sensor (5) is attached, and at least one of a side frame (7) that supports the slide (4) so as to be able to move up and down. A partition wall (3) for preventing conduction of heat generated by the servomotor (2) by direct or convection is provided on the slide (4), slide position sensor (5), auxiliary frame (6) and side frame ( A device for avoiding thermal displacement of an electric servo press, characterized in that a change in die height due to thermal displacement of each part of 7) is suppressed. 3. A suction means (20) for sucking warm air due to heat generation of the servo motor (2) is provided near the upper side of the output shaft of the servo motor (2). A thermal displacement avoidance device for the electric servo press described.