Pressing device

Abstract

To provide a press device that can accurately detect a position or the like of a slide, not only in short stroke press but also in long stroke press, and is hardly influenced by a foreign matter from an installation environment of press.SOLUTION: A press device 1 comprises: a bed 3 on which a lower mold 17 can be mounted; a slide 8 on which an upper mold 12 can be mounted and which can move toward the lower mold 17 together with the upper mold 12; a scale member 21 having a scale arranged along a moving direction of the slide 8; and an optical detector 20 that reads the scale while moving along the scale member 21 in tandem with movement of the slide 8, which detects a position y or a speed v of the slide 8 on the basis of the scale read by the optical detector 20.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD

[0001] The present invention relates to a press apparatus.

BACKGROUND ART

[0002] For example, hydraulic press apparatuses are characterized by being capable of generating the maximum load at any position from the upper limit to the lower limit of the stroke, and are suitable for long-stroke molding and for molding methods that perform molding while precisely controlling the position and speed of the slide. In order to precisely control the position and the like of the slide in the moving direction, the position and the like of the slide must be accurately detected.

[0003] As a method for detecting the position and the like of a slide, for example, a method using a magnetostrictive sensor as described in Patent Document 1 is known. Further, as described in Patent Document 2, a method is also known in which the linear motion of a slide is converted into rotational motion using a rack and pinion, and the rotation angle is measured with a rotary encoder or a servomotor having the same.

PRIOR ART DOCUMENTS

PATENT DOCUMENTS

[0004]

PATENT DOCUMENT 1

PATENT DOCUMENT 2

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] However, although a magnetostrictive sensor is a high-resolution sensor, it has a problem that the linearity error of measured values increases in proportion to the stroke of the sensor. When the linearity error increases in this manner, the reliability of measured values deteriorates when measuring the position and the like of a slide with a long-stroke hydraulic press apparatus. For example, if a magnetostrictive sensor with an error specification of ±0.01% × FS is used in a hydraulic press machine with a slide stroke of 1000 mm, the full scale of the sensor's stroke becomes 1000 mm, resulting in a relatively large error in the measured value of ±0.1 mm (= ±100 μm) from the theoretical value.

[0006] Furthermore, while the press apparatus described in Patent Document 2 incorporates measures to prevent a decrease in position detection accuracy due to backlash, when converting the linear motion of a slide into rotational motion and measuring the rotation angle with a rotary encoder or servo motor, it is generally not easy to eliminate backlash or play in the rotary joint, or to maintain and manage the machining accuracy and meshing accuracy of the gears. Furthermore, if foreign matter such as dust and debris generated in the press installation environment enters the meshing parts of the gears, it can cause errors in the measurement of the rotation angle by rotary encoders, etc. Also, if foreign matter adheres to the gears, the meshing parts will wear down over time, impairing the precision of the rotation angle measurement.

[0007] This invention has been made in view of the above points, and aims to provide a press device that can accurately detect the position of the slide, etc., not only in short-stroke presses but also in long-stroke presses, and that is less susceptible to the influence of foreign matter from the press installation environment. [Means for solving the problem]

[0008] The press apparatus according to the present invention is A bed to which a lower mold can be attached, The upper mold can be attached. ,before A slide that can move toward the lower mold together with the upper mold, A scale member having a scale provided along the direction of movement of the slide, Linked to the movement of the aforementioned slide It is supported via a mounting part so as to move the slide An optical detector that moves in conjunction with the scale member and reads the scale, Equipped with, The optical detector and the scale member are covered by a housing with the mounting portion extended to the outside. The scale member is ,before The side of the bed below the top surface of the bed Directly fixed only to the side, or indirectly fixed only to the side via a fixing member. It is fixed in place. The position or speed of the slide is detected based on the scale read by the optical detector. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a press device that can accurately detect the position of the slide, etc., not only in short-stroke presses but also in long-stroke presses, and that is less susceptible to the influence of foreign matter from the press installation environment. [Brief explanation of the drawing]

[0010] [Figure 1] This diagram shows the configuration of the press apparatus according to this embodiment. [Figure 2] (a) is an enlarged view of a part of the press device including an optical detector and a scale member, and (b) is a view of the part in (a) from above. [Figure 3] This diagram shows an example configuration in which an optical detector and a scale element are enclosed in a housing. [Figure 4] This diagram shows the configuration of the press apparatus according to this embodiment, including the control unit and other components. [Figure 5] This is a flowchart illustrating the procedure for controlling the position of the slide in the press apparatus according to this embodiment. [Figure 6] This is a diagram illustrating an example of slide motion. [Figure 7] This flowchart shows the procedures for each process in the control unit, including the control of the slide's parallelism. [Modes for carrying out the invention]

[0011] Hereinafter, embodiments of the press apparatus according to the present invention will be described with reference to the drawings. While the following description will focus on the case where the press apparatus is a hydraulic press apparatus, the present invention can also be applied to other types of press apparatus, such as mechanical press apparatuses.

[0012] Figure 1 is a diagram showing the configuration of the press device according to the present embodiment. The press device 1 includes a frame 5 constituted by a crown 2, a bed 3, uprights 4 erected between them, and the like. The crown 2 and the bed 3 are fastened by tie rods 6 inserted into the uprights 4.

[0013] The crown 2 is provided with a main cylinder 7, and a slide 8 is fixed to the lower end of a ram rod 7a of the main cylinder 7. The slide 8 is configured to move downward as the ram rod 7a of the main cylinder 7 moves downward. Further, gib blocks 9 are respectively attached to the four corners of the slide 8. The gib blocks 9 are configured to guide the slide 8 in the vertical direction by moving in the vertical direction along the uprights 4 when the slide 8 moves in the vertical direction.

[0014] A slide hard plate 10 is fixed to the lower surface of the slide 8, and an upper die 12 can be attached to the lower surface side of the slide hard plate 10 via an upper die holder 11. Further, a slide fall prevention device 13 fixed to one or a plurality of corner portions of the slide 8 is attached to the upright 4, and the slide fall prevention device 13 prevents the slide 8 from falling.

[0015] Further, the lower end portions of ram rods 14a of four pullback cylinders 14 provided at corresponding portions of the crown 2 are respectively attached to the four corners on the upper surface side of the slide 8. The ram rod 14a of the pullback cylinder 14 moves upward, so that the lowered slide 8 is moved upward and pulled back. Note that the pullback cylinders 14 may be provided at other positions.

[0016] Furthermore, a bed hard plate 15 is fixed to the upper surface of the bed 3, and the lower mold 17 is attached to the upper side of the bed hard plate 15 via a lower mold holder 16. As a result, the slide 8 can move toward the lower mold 17 together with the upper mold 12. The press device 1 is configured to forge or press-work a workpiece (not shown) between the lower die 17 and the upper die 12, which descends as the slide 8 moves downward.

[0017] On the other hand, as shown in Figure 1, in this embodiment, a mounting bracket 19 is fixed to the lower surface of the gib block 9 via a connecting rod 18, and an optical detector 20 is attached to the mounting bracket 19. Furthermore, a scale member 21, which has markings (not shown), is positioned near the optical detector 20, along the vertical direction which is the direction of movement of the slide 8. Although not shown, the markings are provided on the substrate at predetermined intervals along the direction of movement of the slide 8.

[0018] Figure 2(a) is an enlarged view of a part of the press apparatus including an optical detector and a scale member, and Figure 2(b) is a view of this part from above. In this embodiment, the scale member 21 is attached to the bed 3 and to a fixing plate 22 that extends in the vertical direction.

[0019] Furthermore, a linear guide 23 is attached to the fixing plate 22 so as to extend in the vertical direction, and a mounting bracket 19 is attached to this linear guide 23 so as to be movable in the vertical direction. Furthermore, since the linear guide 23 is installed so that its guide axis is strictly parallel to the axial direction of the scale member 21, the optical detector 20 attached to the mounting bracket 19 moves accurately and smoothly in the axial direction of the scale member 21.

[0020] The aforementioned connecting rod 18 is made of a non-extendable metal rod or the like. Therefore, when the slide 8 moves vertically as described above, that movement is transmitted to the mounting bracket 19 and the optical detector 20 via the connecting rod 18. Therefore, the optical detector 20 moves vertically parallel to the scale member 21 in conjunction with the vertical movement of the slide 8, and reads the scale on the scale member 21. Based on the scale read by the optical detector 20, the position y of the slide 8 (i.e., its vertical position) is detected.

[0021] Furthermore, when using the optical detector 20 and scale member 21 solely to detect the position y (or velocity v) of the slide 8, the combination of the optical detector 20 and scale member 21 may be provided in only one location on the bed 3, rather than being provided in multiple locations as shown in Figure 1. Furthermore, the provision of optical detectors 20 and scale members 21 at multiple locations on the press device 1 will be explained later in the section on parallelism control in slide 8.

[0022] When reading the scale of the scale member 21 with the optical detector 20, it is possible to configure the optical detector 20 so that light emitted from a light-emitting element (not shown) is reflected by the scale member 21, and the reflected light is received and read by a light-receiving element (not shown). Furthermore, it is also possible to configure the optical detector 20 so that light emitted from the light-emitting element is transmitted through the scale member 21, and the transmitted light is received and read by a light-receiving element. There are no particular restrictions on how the optical detector 20 reads the scale of the scale member 21.

[0023] In this embodiment, as described above, the case in which the scale member 21 and optical detector 20 are attached to the press device 1 by attaching the scale member 21 and the like to a fixed plate 22 attached to the bed 3, is explained. However, it is also possible to configure the scale member 21 to be integrally formed with the bed 3, etc. Furthermore, instead of detecting the position y of the slide 8 based on the scale of the scale member 21 read by the optical detector 20 as described above, it is also possible to configure the system to detect the velocity v of the slide 8 (i.e., the speed of movement in the vertical direction) by dividing the position detected at each sampling timing by the sampling timing.

[0024] Furthermore, while the optical detector 20 and the scale member 21 may be pulse-count type increment type, it is more preferable to use an absolute type that detects absolute position information (so-called address). In this case, there is a one-to-one correspondence between the position of slide 8 and the absolute position information of the scale markings on the scale member 21. Therefore, if a correspondence table between the position of slide 8 and the absolute position information of the scale is prepared in advance, for example, the position of slide 8 can be determined if the absolute position information of the scale is known.

[0025] Furthermore, by making the scale of the scale member 21 an absolute type, for example, when restarting the press device 1 after it has stopped due to a power outage, the position of the slide 8 at that time can be determined by reading the absolute position information of the scale, thus eliminating the need for a return to the origin position operation. It goes without saying that even with an increment type mechanism, the position of the slide 8 can be detected by reading the scale on the scale member 21.

[0026] Next, the operation of the press apparatus 1 according to this embodiment will be described. In the following section, we will describe the case where the vertical position of the slide 8 is detected using the optical detector 20 and the scale member 21, as described above. However, as previously mentioned, it is also possible to configure the system to detect the speed of the slide 8.

[0027] As mentioned above, when converting the linear motion of slide 8 into rotational motion and measuring its vertical position, for example, by using a rack and pinion, it is not always easy to eliminate gear backlash and rotary coupling play, as well as to maintain and manage the machining accuracy and meshing accuracy of the gears. Furthermore, if foreign matter such as dust and debris from the press installation environment enters the gear meshing parts, errors can occur in the measurement of the rotation angle by rotary encoders, etc. In addition, if foreign matter adheres to the gears, the meshing parts will wear down over time, which can impair the precision of the rotation angle measurement.

[0028] Furthermore, if the linear motion of slide 8 is not converted to rotational motion, and its vertical position is measured using, for example, a magnetostrictive sensor, there is a problem in that the linearity error of the measured value increases in proportion to the stroke of the sensor. Therefore, for example, if a magnetostrictive sensor with an error specification of ±0.01% × FS is used in a long-stroke press machine such as one with a stroke of 1000 mm, there was a problem in that the error in the measured value became a relatively large error of ±0.1 mm (= ±100 μm) from the theoretical value.

[0029] In contrast, if the press apparatus 1 of this embodiment is configured such that the optical detector 20 moves along the scale member 21 in conjunction with the movement of the slide 8 and detects the vertical position of the slide 8 based on the scale of the scale member 21 read, the resulting error is approximately ±5 μm from the theoretical value, regardless of the total length of the scale member 21 (i.e., the effective measurement length of the sensor). As described above, with the configuration in this embodiment, the error does not depend on the total length of the scale member 21 (i.e., the error does not increase in proportion to the sensor scale as in the magnetostrictive sensor described above), and the deviation from the theoretical value is within ±5 μm regardless of which part of the scale member 21 is read. Therefore, in this embodiment, it is possible to accurately detect the position of the slide 8 even in a long-stroke press.

[0030] Furthermore, in the press apparatus 1 of this embodiment, even if foreign matter such as dust or debris is generated during pressing and gets between the optical detector 20 and the scale member 21, the error will not exceed the above ±5 μm unless it interferes with the optical detector 20's ability to read the scale on the scale member 21. Also, since the optical detector 20 and the scale member 21 are not in contact, the optical detector 20 and the scale member 21 will not be worn down by foreign matter. Therefore, in this embodiment, the press device 1 can be made less susceptible to the influence of foreign matter from the press installation environment.

[0031] As described above, the press apparatus 1 according to this embodiment makes it possible to accurately detect the position (or speed) of the slide 8 not only in the case of a short-stroke press, but also in the case of a long-stroke press. Furthermore, it becomes possible to make the press device 1 less susceptible to the influence of foreign matter from the press installation environment.

[0032] [Regarding the structure and other aspects of protection against foreign objects] In this embodiment, the optical detector 20 and the scale member 21 are designed to be less susceptible to foreign matter, as described above. However, it is also possible to configure the optical detector 20 and the scale member 21 in such a way that foreign matter does not enter between them, or enters them less easily. For example, as shown in Figure 3, the optical detector 20 and the scale member 21 can be configured to be covered by a housing 24. Although not shown in the illustration, the upper and lower ends of the housing 24 are sealed.

[0033] By configuring the optical detector 20 and the scale member 21 to be covered by the housing 24 in this way, it becomes possible to configure the system so that foreign matter does not enter, or is less likely to enter, between the optical detector 20 and the scale member 21. In this case, the scale member 21 is fixed inside the housing 24. A plate-shaped mounting piece 25 is attached to the optical detector 20, and the mounting piece 25 is pulled out to the outside through a slit 24a provided in the housing 24 and attached to a mounting bracket 19 (not shown in Figure 3). As a result, the optical detector 20 can move along the scale member 21 while facing the scale member 21 fixed to the housing 24.

[0034] In this case, however, there is a possibility that foreign matter such as dust and debris may enter the housing 24 through the slit 24a. Therefore, for example, as shown in Figure 3, if a sealing material 24b is provided in the slit 24a and the mounting piece 25 is pulled outwards through a slit in the sealing material 24b, it becomes possible to prevent foreign matter from entering the housing 24 with the sealing material 24b. Furthermore, by making the air pressure inside the housing 24 higher than the outside air pressure, it is possible to create an airflow from inside the housing 24 toward the outside through the crack in the sealing material 24b, thereby making it difficult for foreign matter to enter the housing 24.

[0035] Furthermore, it is also possible to configure the system so that foreign matter does not enter, or is less likely to enter, the space between the optical detector 20 and the scale member 21, by blowing air towards the space between the optical detector 20 and the scale member 21. In addition, configurations that prevent foreign matter from entering or making it difficult for foreign matter to enter between the optical detector 20 and the scale member 21 can be appropriately adopted.

[0036] [Regarding slide position control or speed control] As shown in Figure 4, the press apparatus 1 according to this embodiment includes a control unit 30 consisting of a computer and a dedicated device, and the control unit 30 controls the position or speed of the slide 8 based on the detected position or speed of the slide 8. It is also possible to configure the control unit 30 to perform the detection process of the position or velocity of slide 8. Furthermore, although the following description will focus on controlling the position of slide 8 based on the detected position of slide 8, the same description will be given for controlling the velocity of slide 8 based on the detected velocity of slide 8. When performing velocity control, it is possible to configure the system to control the velocity v as the derivative of the actual position y, as described below.

[0037] In this embodiment, a hydraulic control block 31 is provided for supplying and discharging hydraulic fluid to and from the oil chamber 7c, which is surrounded by the ram rod 7a and cylinder tube 7b of the main cylinder 7. The control unit 30 controls the vertical position of the slide 8, particularly the position when the slide 8 is lowered, according to the slide motion set by the user. This is achieved by adjusting the amount of hydraulic fluid discharged from the main cylinder 7 to the oil chamber 7c (flow rate of hydraulic fluid supplied to the oil chamber 7c) by controlling the opening degree of a valve (not shown) in the hydraulic control block 31, or by controlling the rotation speed of a servo motor (not shown).

[0038] In this embodiment, each return cylinder 14 is also provided with a hydraulic control block 32 for supplying and discharging hydraulic fluid to and from the oil chamber surrounded by the ram rod 14a and the cylinder tube 14b. Each hydraulic control block 32 supplies hydraulic fluid to its oil chamber in accordance with the downward movement of the slide 8, and when it receives a pull-back instruction from the control unit 30, it discharges hydraulic fluid from its oil chamber to raise (pull back) the slide 8.

[0039] The position control of the slide 8 in the press apparatus 1 according to this embodiment will be described in detail below based on the flowchart shown in Figure 5. In the following description, we will explain the case where the control unit 30 controls the opening degree of the valve of the hydraulic control block 31, but the same applies when controlling the rotational speed of the servo motor.

[0040] When performing forging or press working with the press device 1, the user first sets the slide motion S to the control unit 30 of the press device 1 (step S1). Slide motion S is a pattern of movement of slide 8, as shown in Figure 6, for example, and is a pattern of the position Y of slide 8 (for example, the stroke downwards from the top dead center) with respect to the elapsed time t from the start of the slide 8's motion. When speed control is performed, slide motion S becomes a pattern of the speed v of slide 8 with respect to the elapsed time t.

[0041] Next, the control unit 30 determines the position Y (velocity v in the case of velocity control; the same applies hereinafter) that the slide 8 should be at at the elapsed time t, based on the slide motion S and the elapsed time t from the start of the slide 8's motion. The control unit then calculates the valve opening degree of the hydraulic control block 31 so that the slide 8 is at that position Y at the elapsed time t, and instructs the hydraulic control block 31 (step S2). The hydraulic control block 31 opens the valve to the opening degree indicated by the instruction signal, supplying hydraulic fluid to the oil chamber 7c of the main cylinder 7, and lowering the ram rod 7a to lower the slide 8 to the indicated position Y.

[0042] Next, when the control unit 30 receives the detection result (absolute position information (address) in the case of an absolute type) detected by the optical detector 20 reading the scale of the scale member 21 (step S3), it adjusts the opening degree of the valve of the hydraulic control block 31 based on the detection result and the slide motion S (step S4).

[0043] As a method for adjusting the valve opening of the hydraulic control block 31, for example, it is possible to configure the system to determine the actual position y of the slide 8 based on the detection result of the optical detector 20, and then perform feedback control so that the slide 8 approaches the position Y (i.e., the theoretical value) that it should be in at the elapsed time t determined based on the slide motion S. Furthermore, in addition to feedback control, it is also possible to configure the system to perform feedforward control by predicting vibrations that occur in the slide 8 when, for example, the upper mold 12 (see Figure 4) comes into contact with a workpiece (not shown), and various control methods can be employed.

[0044] Regardless of how the position control of slide 8 is configured, if, for example, a magnetostrictive sensor with the aforementioned error specification of ±0.01% × FS is used, then if the stroke of slide 8 is, for example, 1000 mm, the error between the theoretical position Y of slide 8 and the actual position y could be up to ±0.1 mm, or ±100 μm. For example, when forging a workpiece with press machine 1, this could result in a dimensional deviation of up to 200 μm in the product. Therefore, there is a possibility of molding defects, etc.

[0045] Furthermore, for example, in cases where the speed at which the slide 8 descends during the molding process is changed based on the position Y of the slide 8, as shown in the slide motion S in Figure 6, if the error is large as described above, the timing of changing the speed at which the slide 8 descends during the molding process will deviate from the theoretical value. Therefore, the actual molding conditions of the product may differ from the molding conditions set in Slide Motion S.

[0046] In contrast, using the press apparatus 1 according to this embodiment, regardless of whether the stroke of the slide 8 is a long stroke or a short stroke, the error will be limited to a small error of, for example, ±5 μm. Therefore, the product will only have a dimensional deviation of about 10 μm at most, and the possibility of molding defects and other problems is extremely small.

[0047] Furthermore, even in cases where, for example, the speed at which slide 8 is lowered during the molding process of the workpiece is changed based on the position Y of slide 8, it is possible to change the speed at almost the same timing as the theoretical value. Therefore, it becomes possible to mold the product using the molding conditions set by the slide motion S.

[0048] If the motion of the slide 8 instructed by the input slide motion S (such as downward movement) has not been completed (step S5; NO), the control unit 30 repeats each of the above steps S2 to S4 to continue the motion of the slide 8 and continue shaping the workpiece. Furthermore, once the series of motions of slide 8 instructed by the input slide motion S is completed (step S5; YES), and unless the end of the operation has not been instructed (step S6; NO), slide 8 is pulled upward in preparation for molding the next workpiece (step S7), and then each process from step S2 onwards is performed for the next workpiece. Furthermore, if the control unit 30 is instructed to complete the work (step S6; YES), it pulls the slide 8 back to its predetermined position (step S8) and completes the work.

[0049] As described above, with the press apparatus 1 according to this embodiment, the position of the slide 8 can be detected with high accuracy using the optical detector 20 and the scale member 21, making it possible to control the position of the slide 8 with high accuracy. Furthermore, even when configured to control the speed of the slide 8, it is possible to control the speed of the slide 8 with high accuracy. Therefore, the reliability of the position and speed control of slide 8 is improved, and this also leads to an improvement in product quality.

[0050] Furthermore, the position and speed control of slide 8 can be performed based on the position and speed of slide 8 detected using an optical detector 20 or the like, and does not necessarily have to follow the flowchart shown in Figure 5. Furthermore, it goes without saying that it is possible to combine the above-mentioned position control and speed control of slide 8 with other appropriate processing, such as stopping the movement of slide 8 if the error between the theoretical position Y of slide 8 and its actual position y becomes abnormally large, or if there is an abnormality in the hydraulic pressure of the oil chamber 7c.

[0051] [Regarding slide parallelism control] On the other hand, it is also possible to configure the press apparatus 1 according to this embodiment to control the parallelism of the slide 8. In the following, we will explain how to control the parallelism of slide 8 based on the detected position of slide 8, but we will also explain how to control the parallelism of slide 8 based on the detected speed of slide 8 in the same way. Furthermore, in the following, we will explain how to control the parallelism by adjusting the positions of the four corners of slide 8, but the points to be adjusted do not necessarily have to be four.

[0052] In this case, as shown in Figure 4, for example, the combination of the optical detector 20 and the scale member 21 (including the connecting rod 18, etc.) described above is provided at four locations on the bed 3, corresponding to the four corners of the slide 8. In Figure 4, optical detectors 20 and scale members 21 are shown to be attached to two locations on the front side of bed 3, but combinations of optical detectors 20 and scale members 21 are also placed at two locations on the back side of bed 3.

[0053] Then, using each combination of the optical detector 20 and the scale member 21, the position y of different locations on the slide 8 (in this case, the four corners of the slide 8) is detected. Furthermore, the control unit 30 can be configured to perform parallelism control of the slide 8 based on the respective positions y (hereinafter referred to as positions y1 to y4) detected at each of the four corners of the slide 8.

[0054] On the other hand, when controlling the parallelism of the slide 8, it is possible to configure the system to control the parallelism of the slide 8 by appropriately operating the retraction cylinders 14 attached to the four corners of the slide 8. In this case, the system is configured to allow adjustment of the amount of hydraulic fluid discharged into the oil chamber of each return cylinder 14 and the amount of hydraulic fluid discharged from the oil chamber by controlling the opening degree of a valve (not shown) or by controlling the rotational speed of the servo motor of the hydraulic control block 32 of each return cylinder 14.

[0055] With this configuration, it becomes possible to adjust the pulling force of each pull-back cylinder 14 by the ram rod 14a by controlling the valve opening or the rotation speed of the servo motor of the hydraulic control block 32 of each pull-back cylinder 14. Therefore, as described above, when the slider 8 moves downward due to the operation of the main cylinder 7, if any of the positions y1 to y4 of the slide 8 are starting to drop lower than the other positions, the ram rod 14a of each pull-back cylinder 14 corresponding to that position is adjusted to apply an upward force to that position, thereby keeping the slide 8 horizontal and enabling control of the parallelism of the slide 8.

[0056] The following describes in detail the control of the parallelism of the slide 8 in the press apparatus 1 according to this embodiment. In the following description, we will explain the case where the control unit 30 controls the opening degree of the valve of the hydraulic control block 31, but the same applies when controlling the rotational speed of the servo motor. Also, the method of controlling the parallelism of the slide 8 described below is just one example, and other control methods can be adopted as long as the parallelism of the slide 8 is controlled based on the respective positions y1 to y4 (or speeds) detected for each part of the slide 8.

[0057] The parallelism of slide 8 is controlled within the position control shown in Figure 5. After performing steps S1 and S2 in Figure 5, the control unit 30 receives the detection results detected by each optical detector 20 (in this case, four optical detectors 20) by reading the scale of the scale member 21 (step S3). Then, as a process corresponding to step S4 in Figure 5, the control unit 30 calculates the average value of the actual positions y1 to y4 of the four corners of the slide 8, which are determined based on the detection results of each optical detector 20, as shown in the flowchart of Figure 7.

[0058] Then, the control unit 30 adjusts the valve opening of the hydraulic control block 31 of the main cylinder 7 based on the calculated average value of positions y1 to y4 and the slide motion S (step S41), and uses the main cylinder 7 to control the position of the slide 8. In other words, the control unit 30 controls the position of the slide 8 by using the average value of the positions y1 to y4 at the four corners of the slide 8 as the actual position y of the slide 8 as described above.

[0059] At the same time, the control unit 30 controls the parallelism of the slide 8. Specifically, the control unit 30 calculates the difference Δy1 to Δy4 between the position of the slide 8 after position adjustment (position Y as a theoretical value) and the positions y1 to y4 at each of the four corners of the slide 8 (step S9). Then, based on the calculated difference Δy1 to Δy4, the opening degree of the valve in the hydraulic control block 32 of the pull-back cylinder 14 corresponding to each position y1 to y4 is adjusted (step S10), and the parallelism of the slide 8 is controlled using each of the pull-back cylinders 14.

[0060] In other words, if each position y1 to y4 is lower than the adjusted position of the slide 8, the control unit 30 operates each of the pull-back cylinders 14 corresponding to each of the positions y1 to y4 as appropriate to fine-tune the pulling force applied to each position y1 to y4 so that the slide 8 is at the adjusted position, thereby controlling the parallelism of the slide 8. In this way, the control unit 30 controls the parallelism of the slide 8 each time it controls the position (or speed) of the slide 8.

[0061] As described above, the press apparatus 1 according to this embodiment is equipped with multiple combinations of optical detectors 20 and scale members 21 that can accurately detect the position of the slide 8 as described above. By using these combinations to detect the positions y1 to y4 (or speeds) of different parts of the slide 8, and performing parallelism control of the slide 8 based on the detected positions y1 to y4 (or speeds) for each part, it becomes possible to precisely control the slide 8 so that it does not tilt. Therefore, it becomes possible to precisely control the mold (upper mold) to prevent any tilting.

[0062] Therefore, it becomes possible to precisely control the thickness of the product, leading to improved product quality. Furthermore, the large slide 8 makes it possible to prevent buckling during the molding of large presses and long parts, which also has the advantage of expanding the range of product shapes that can be molded.

[0063] It goes without saying that the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention. [Explanation of symbols]

[0064] 1. Pressing device. 3 beds 8 slides 12 Upper mold 14 Retraction Cylinder 17 Lower mold 20 Optical detectors 21 Scale member 24 Housing 30 Control Unit v speed y, y1~y4 position

Claims

1. A bed to which a lower mold can be attached, A slide to which an upper mold can be attached and which can move toward the lower mold together with the upper mold, A scale member having a scale provided along the direction of movement of the slide, An optical detector is supported via a mounting portion so as to move in conjunction with the movement of the slide, and moves along the scale member in conjunction with the movement of the slide to read the scale, Equipped with, The optical detector and the scale member are covered by a housing with the mounting portion extended to the outside. The scale member is either directly fixed only to the side surface of the bed below the upper surface of the bed, or indirectly fixed only to the side surface via a fixing member. The optical detector detects the position or speed of the slide based on the scale it reads. Pressing device.

2. The system includes a control unit that performs position control or speed control of the slide based on the detected position or speed of the slide, The press apparatus according to claim 1.

3. The system comprises multiple combinations of the optical detector and the scale member, For each of the above combinations, the position or speed of a different part of the slide is detected, The control unit performs parallelism control of the slide based on the position or speed detected for each part of the slide. The press apparatus according to claim 2.

4. A retraction cylinder for pulling the slide back in a predetermined direction is attached to different parts of the slide. The control unit operates each of the retraction cylinders based on the respective positions or speeds detected for each part of the slide, thereby controlling the parallelism of the slide. The press apparatus according to claim 3.

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