Press device

Abstract

To measure a load accurately with a simple structure during operation of a press device.SOLUTION: A press device 1 includes: a frame 10 which supports a slider 2 in a manner that enables reciprocating movement; and a drive part 20 which drives the slider 2. The drive part 20 has: a motor 24 which generates processing force; a link member 23 which transmits the processing force generated by the motor 24 to the slider 2; and a support shaft 15b which supports the link member 23 in a manner that allows the link member 23 to swing relative to the frame 10. The link member 23 is attached with a strain gauge 51 which outputs an electric signal generated according to a deformation amount.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a press device capable of measuring a load during processing. [Background technology]

[0002] For example, Patent Document 1 discloses a press machine in which a slider supported so as to be capable of reciprocating up and down relative to a machine body is driven by the output of a servo motor. This press machine has a strain gauge that measures the deformation of the machine body when the slider moves during a press operation, and a control unit that converts the output of the strain gauge into a load conversion value, and is configured to be able to control a motor driver to stop driving the servo motor when the load conversion value exceeds an upper load limit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-46354 A Summary of the Invention [Problem to be solved by the invention]

[0004] By measuring the load when the press device is in operation, it is possible to determine whether processing is performed normally or not, and to discover abnormalities in the press device. In the case of Patent Document 1, when the die is moved by the slider to press the workpiece, the workpiece simultaneously presses the machine body, and the reaction force generated by this is transmitted to the machine body via the slider. As a result, the machine body is elastically deformed, and in order to detect this elastic deformation, a strain gauge is placed on the side wall surface of the machine body.

[0005] However, when the inventors of the present application placed strain gauges on the machine body and tried to measure the load during actual pressing, they found that the reliability of the measured value was low. That is, the machine body is made highly rigid because it is a member to which a heavy slider and die are attached, and because it is necessary to move the die with high precision to improve the accuracy of the press, and even if a load acts during pressing, the elastic deformation of the machine body is extremely small. Therefore, it becomes difficult to judge the linearity when converting the output of the strain gauge into a load conversion value, and the output from the strain gauge becomes low, and the noise becomes large when amplified. Both the difficulty in judging the linearity and the large noise cause a decrease in measurement accuracy.

[0006] The present disclosure has been made in consideration of the above points, and an object of the present disclosure is to make it possible to measure the load during operation of a press device with high accuracy using a simple configuration. [Means for solving the problem]

[0007] In order to achieve the above object, one aspect of the present disclosure can be based on a press device that processes a workpiece with a processing tool by reciprocating a slider to which the processing tool is attached. The press device includes a frame that supports the slider so that the slider can reciprocate, a drive unit that drives the slider, and a load measurement unit that measures the load during processing by the processing tool. The drive unit includes a processing force generating unit that generates a processing force, a link member that transmits the processing force generated by the processing force generating unit to the slider, and a support shaft that supports the link member so that it can swing freely relative to the frame. The load measurement unit includes a strain gauge that is attached to the link member and outputs an electrical signal corresponding to the deformation amount of the link member, and a conversion processing unit that converts the electrical signal output from the strain gauge into the load.

[0008] According to this configuration, the processing force generated in the processing force generating unit is transmitted to the slider via the link member, and the workpiece is processed by the processing tool. When the workpiece is processed, the link member that receives the reaction force from the workpiece is elastically deformed. At this time, the frame is a member that supports the slider and also affects the processing accuracy, so it has high rigidity and is difficult to deform. On the other hand, the link member that transmits the processing force generated in the processing force generating unit to the slider has lower rigidity than the frame, so the amount of elastic deformation during processing is larger than that of the frame. Since the strain gauge is attached to this link member, it is easier to determine the linearity when converting the output of the strain gauge into a load conversion value, and the output from the strain gauge is also high. Therefore, the accuracy and reliability of the measurement results obtained by the conversion processing unit are improved.

[0009] The link member may have an insertion hole through which the support shaft passes. In this case, the strain gauge can be attached to a portion of the link member that has been thinned by forming the insertion hole. That is, the portion of the link member in which the insertion hole is formed is thinner than other portions of the link member, and therefore the amount of elastic deformation during processing is large. Since the strain gauge is attached to this portion with a large amount of elastic deformation, the output of the strain gauge is high, and the accuracy and reliability of the measurement results are further improved.

[0010] The link member may have one longitudinal end to which the processing force generated by the processing force generating unit is input, and the other longitudinal end to which the slider is connected. In this case, the insertion hole may be formed in the longitudinal middle portion of the link member. With this configuration, a bending force acts on the link member during processing, and the link member to which the bending force acts undergoes greater deformation around the insertion hole, which is relatively thin. This allows the output of the strain gauge to be increased.

[0011] The support shaft may extend horizontally, the slider may be supported on the front side as viewed by a user of the frame, and the link member may be arranged to extend from the front side to the back side as viewed by a user of the frame. In this case, the insertion hole extends horizontally, one end of the link member in the longitudinal direction is arranged on the back side as viewed by a user of the frame, and the other end of the link member in the longitudinal direction is arranged on the front side as viewed by a user of the frame, and the strain gauge may be attached to the upper or lower surface of the link member. According to this configuration, a bending force in the vertical direction acts on the link member during processing. Therefore, by attaching the strain gauge to the upper or lower surface of the link member, the output of the strain gauge can be increased.

[0012] A plurality of the strain gauges may be attached to the upper surface of the link member, and a plurality of the strain gauges may be attached to the lower surface of the link member, thereby further improving the measurement accuracy of the load during processing. Effect of the Invention

[0013] As described above, the load during processing is measured based on the output of the strain gauge attached to the link member that transmits the processing force to the slider, so the load during operation of the press device can be measured with high accuracy using a simple configuration. [Brief description of the drawings]

[0014] [Figure 1] 1 is a perspective view of a press apparatus according to an embodiment of the present invention, as viewed from above. [Diagram 2] FIG. 2 is a perspective view of the press apparatus with the cover removed, as viewed from above. [Diagram 3] FIG. 2 is a side view of the press apparatus with the cover removed, showing the slider at the top dead center position. [Figure 4] FIG. 2 is a side view of the press apparatus with the cover removed, showing the slider at the bottom dead center position. [Diagram 5] FIG. 4 is a side view of a third link member. [Figure 6] FIG. 4 is a plan view of a third link member. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the following description of the preferred embodiments is merely illustrative in nature and is not intended to limit the present invention, its applications, or its uses.

[0016] FIG. 1 is a perspective view of a press device 1 according to an embodiment of the present invention, as viewed from above. Also, FIGS. 2 to 4 are diagrams showing the internal structure of the press device 1. FIG. 3 shows a case where the slider 2 is at the top dead center position, and FIG. 4 shows a case where the slider 2 is at the bottom dead center position. This press device 1 is a device for processing a workpiece with a processing tool (not shown) by reciprocating the slider 2 to which the processing tool is attached. Processing by the press device 1 includes, for example, crimping, bending, drilling, shearing (cutting), and the like. When processing by the press device 1, a processing tool (not shown) according to the type of processing is used. Also, the workpiece may be made of, for example, metal or resin.

[0017] In the description of this embodiment, the side that is in front when viewed from the user of the press apparatus 1 will be simply referred to as the front side, the side that is in front when viewed from the user of the press apparatus 1 will be simply referred to as the back side, the side that is to the left when viewed from the user of the press apparatus 1 will be simply referred to as the left side, and the side that is to the right when viewed from the user of the press apparatus 1 will be simply referred to as the right side. These definitions of directions are provided for the convenience of description, and do not limit the directions of the press apparatus 1 when in use.

[0018] The press device 1 includes a frame 10 that supports the slider 2 so as to be capable of reciprocating motion, a drive unit 20 (shown in Figs. 2 to 4) that drives the slider 2, and a cover 30 (shown only in Fig. 1). The cover 30 is formed so as to cover the slider 2, the frame 10, the drive unit 20, etc., and is detachably attached to the frame 10.

[0019] The frame 10 is made of a highly rigid metal member. A base 11 is fixed to the front side of the lower part of the frame 10. The base 11 extends in the left-right and depth directions at the front side of the press device 1. A workpiece (not shown) can be placed on the upper surface of the base 11. The base 11 is also made of a highly rigid metal member. Meanwhile, as shown in Figures 2 and 3, legs 12 are provided at the rear side of the lower part of the frame 10. The legs 12 are spaced apart from the base 11 toward the rear.

[0020] The frame 10 extends in the left-right direction and also in the up-down direction. A support 13 for supporting the slider 2 is provided on the front side of the upper part of the frame 10, so that the slider 2 is supported on the front side as seen by a user of the frame 10. In this embodiment, the slider 2 can reciprocate only in the up-down direction directly above the platform 11. Therefore, the support 13 is configured to move the slider 2 only in the up-down direction, and specifically has a left support 13a that guides the left side of the slider 2 in the up-down direction and a right support 13b that guides the right side of the slider 2 in the up-down direction. A processing tool is detachably attached to the lower part of the slider 2. The support 13 is a part of the frame 10.

[0021] The slider 2 has an input member 2a at its upper part. The input member 2a is provided with a front connecting shaft 16 that protrudes in the left-right direction. The front connecting shaft 16 is a part of a drive unit 20.

[0022] The rear portion of the frame 10 has two rear plates 14 (only the right one is shown in the figure) that extend in the vertical direction. These rear plates 14 are spaced apart in the left-right direction. As shown in FIG. 3, a substantially circular lower bearing hole 14b is provided in the lower part of the rear plate 14 so as to penetrate in the left-right direction. Both ends of a lower shaft 14c extending in the left-right direction are supported in the lower bearing hole 14b. The legs 12 are provided in the lower part of the rear plate 14. Furthermore, a motor bracket B is provided in the upper part of the rear plate 14 so as to protrude toward the rear side. The rear plate 14 and the motor bracket B are part of the frame 10.

[0023] The drive unit 20 has a first link member 21, a second link member 22, a third link member 23, and a motor 24. As shown in Fig. 3, the motor 24 is controlled by a motor control unit 40 having a microcomputer or the like. The motor 24 corresponds to a processing force generating unit that generates a processing force of the present invention. An operation button 41 is connected to the motor control unit 40. When the motor control unit 40 detects that the operation button 41 has been operated, it rotates the motor 24 at a set speed. This generates a processing force.

[0024] The timing for reversing the rotation of the motor 24 is when the load value reaches a predetermined value or more, when the operation button 41 is operated, etc. This control by the motor control unit 40 is a conventionally well-known control, and therefore will not be described in further detail.

[0025] The motor 24 is fixed to the motor bracket B with the output shaft 24a extending vertically. The output shaft 24a is provided so as to protrude upward from a main body portion (a portion incorporating a rotor, a stator, etc.) 24b of the motor 24. The center portion of a rotating plate 24c extending horizontally is fixed to the upper end portion of the output shaft 24a.

[0026] One end of the output rod 24d is connected via a pivot 24e (shown in FIG. 3) to a portion of the rotating plate 24c that is away from the center to the periphery. The pivot 24e is attached to the rotating plate 24c so as to protrude upward from the upper surface of the rotating plate 24c. By connecting one end of the output rod 24d to the pivot 24e, the output rod 24d becomes rotatable about an axis extending in the vertical direction, and the inclination angle with respect to the horizontal plane can also be changed.

[0027] The output rod 24d is oriented to extend in the depth direction, with one end of the output rod 24d disposed on the rear side and the other end of the output rod 24d disposed on the front side. An output member 25 is attached to the front end (other end) of the output rod 24d. The front portion of the output member 25 is formed so as to be separated into left and right, and bearing holes 25a are formed on both the left and right sides of the front portion of the output member 25 so as to penetrate in the left-right direction. Both ends of a first shaft 25b extending in the left-right direction are supported by the bearing holes 25a. The first shaft 25b is a part of the drive unit 20.

[0028] The first link member 21, the second link member 22, and the third link member 23 are members for transmitting the machining force generated by the motor 24 to the slider 2. The first link member 21 is disposed between the left and right rear plate portions 14 of the frame 10, and extends in the vertical direction. A substantially circular lower through-hole (not shown) penetrating in the left-right direction is formed in the lower end portion of the first link member 21. The middle portion of the lower shaft 14c is inserted into the lower through-hole of the first link member 21. This allows the first link member 21 to swing freely in the depth direction around the lower shaft 14c. The lower shaft 14c is a part of the drive unit 20.

[0029] The upper portion of the first link member 21 extends above the upper edge of the rear plate portion 14. An upper through-hole (not shown) penetrating in the left-right direction is formed in the upper end of the first link member 21. An intermediate portion of the first shaft 25b is inserted into the upper through-hole of the first link member 21. This connects the upper end of the first link member 21 and the output member 25 to be relatively rotatable about an axis extending in the left-right direction.

[0030] The second link member 22 is disposed so as to extend in the vertical direction. The lower end of the second link member 22 is formed so as to be divided into left and right, and the upper end of the first link member 21 is disposed between the left and right parts of the lower end of the second link member 22. A substantially circular lower through hole (not shown) penetrating in the left and right directions is formed in the left and right parts of the lower end of the second link member 22. The middle part of the first shaft 25b is inserted into the lower through hole of the second link member 22. As a result, the lower end of the second link member 22 and the output member 25 are connected to be relatively rotatable around an axis extending in the left and right direction, and the lower end of the second link member 22 and the upper end of the first link member 21 are connected to be relatively rotatable around an axis extending in the left and right direction. In addition, an upper through hole (not shown) penetrating in the left and right direction is formed in the upper end of the second link member 22.

[0031] A link attachment part 15 is provided at the left-right middle part of the upper part of the frame 10 so as to protrude upward. A substantially circular link support hole 15a is formed in the link attachment part 15 so as to penetrate in the left-right direction. A support shaft 15b for supporting the third link member 23 so as to be able to swing freely with respect to the frame 10 is inserted into the link support hole 15a. The support shaft 15b extends horizontally in the left-right direction and is a part of the drive part 20.

[0032] The third link member 23 is disposed so as to extend from the front side to the back side as viewed from the user of the frame 10. As a result, the longitudinal direction of the third link member 23 corresponds to the depth direction of the frame 10. In this embodiment, two third link members 23 are disposed on the left side and the right side of the link attachment portion 15, respectively. The upper end of the second link member 22 is disposed between the rear ends (longitudinal end portions) of the two third link members 23. The two third link members 23 are made of the same material. The left-right dimension of each third link member 23 is set to be shorter than the left-right dimension of the first link member 21 and the left-right dimension of the second link member 22. The number of third link members 23 is not limited to two, and may be one, or may be three or more.

[0033] The rear end (one end in the longitudinal direction) of the third link member 23 is disposed on the rear side as viewed from the user of the frame 10. A substantially circular rear through hole 23a is formed at the rear end of the third link member 23, penetrating in the left-right direction. The rear through hole 23a is disposed so as to coincide with the upper through hole of the second link member 22. A rear connecting shaft 17 is inserted through the rear through hole 23a and the upper through hole of the second link member 22. The rear connecting shaft 17 is a shaft for connecting the second link member 22 and the third link member 23, and the second link member 22 and the third link member 23 are connected to each other so as to be relatively rotatable around the rear connecting shaft 17. As a result, a processing force generated by the motor 24 is input to one end in the longitudinal direction of the third link member 23 via the second link member 22.

[0034] The front end (the other end in the longitudinal direction) of the third link member 23 is disposed on the front side as viewed from the user of the frame 10. A substantially circular front through hole 23b penetrating in the left-right direction is formed at the front end of the third link member 23. A front connecting shaft 16 is inserted into the front through hole 23b. The front connecting shaft 16 is a shaft for connecting the third link member 23 and the input member 2a, and the third link member 23 and the input member 2a are connected to be relatively rotatable around the front connecting shaft 16. As a result, the slider 2 is connected to the other end in the longitudinal direction of the third link member 23.

[0035] A substantially circular insertion hole 23c, through which the support shaft 15b is inserted, is formed in the longitudinal intermediate portion of the third link member 23 so as to extend horizontally in the left-right direction. The insertion hole 23c penetrates the third link member 23 in the left-right direction. The third link member 23 is connected to the link attachment portion 15 so as to be rotatable around the support shaft 15b.

[0036] The press device 1 is equipped with a load measuring unit 50 for measuring the load during processing by the processing tool. The load measuring unit 50 has a strain gauge 51 attached to the third link member 23 and outputs an electric signal corresponding to the amount of deformation of the third link member 23, and a conversion processing unit 52 for converting the electric signal output from the strain gauge 51 into a load. The strain gauge 51 may be a conventionally known one, and is a mechanical sensor that is attached directly to the surface of the member to be measured and outputs an electric signal corresponding to the amount of mechanical strain of the member. Electricity is supplied to the load measuring unit 50 by a power supply unit (not shown).

[0037] In this embodiment, the strain gauge 51 is attached to a portion of the third link member 23 that has been thinned by the formation of the insertion hole 23c. That is, since the insertion hole 23c of the third link member 23 penetrates in the left-right direction (thickness direction of the third link member 23), the portion of the third link member 23 where the insertion hole 23c is formed has a thinner thickness in the vertical direction compared to a portion where the insertion hole 23c is not formed. The strain gauge 51 is attached to the surface of the portion where the thickness in the vertical direction is thinner.

[0038] Specifically, as shown in Fig. 5, two strain gauges 51 are attached to the upper surface of the third link member 23, and two strain gauges 51 are also attached to the lower surface of the third link member 23. As shown by solid lines in Fig. 6, the two strain gauges 51 on the upper surface of the third link member 23 are arranged at intervals from each other in the longitudinal direction of the third link member 23 and are away from the portion corresponding to the maximum diameter of the insertion hole 23c. The two strain gauges 51 on the lower surface of the third link member 23 are also arranged at intervals from each other in the longitudinal direction of the third link member 23.

[0039] 6, the two strain gauges 51 on the upper surface of the third link member 23 may be arranged with a gap between them in the left-right direction. The same applies to the two strain gauges 51 on the lower surface of the third link member 23. Also, the strain gauges 51 may be provided only on the upper surface of the third link member 23 or only on the lower surface of the third link member 23. Also, the number of strain gauges 51 is not particularly limited, and may be, for example, one, two, three, five or more.

[0040] The strain gauge 51 is electrically connected to the conversion processing unit 52. The electrical signal output from the strain gauge 51 is input to the conversion processing unit 52. The conversion processing unit 52 has an amplifier and the like, and executes a conversion process for converting the electrical signal output from the strain gauge 51 into a load during processing by a processing tool according to a conventionally known method.

[0041] The press apparatus 1 includes a display unit 53 that displays the load measured by the load measuring unit 50. The display unit 53 includes, for example, a liquid crystal display as a device for displaying the load measured by the load measuring unit 50 as a numerical value. The display unit 53 may be omitted.

[0042] The load measuring unit 50 continuously measures the load until the slider 2, which is at the top dead center, slides downward and reaches the bottom dead center. Therefore, the numerical value displayed on the display unit 53 changes until the slider 2 reaches the bottom dead center. Information regarding the position of the slider 2 and information regarding the movement of the slider 2 can be obtained from a control signal output from the motor control unit 40, etc.

[0043] The press apparatus 1 is equipped with a storage unit 54 that stores the load measured by the load measuring unit 50. The storage unit 54 can be configured with, for example, a memory card. The highest load value during one reciprocation of the slider 2 can be stored in the storage unit 54.

[0044] (Operation of press device 1) Next, the operation of the press device 1 configured as described above will be described. As shown in Figures 2 and 3, the slider 2 is at the top dead center before processing begins. When the operator places the workpiece on the top surface of the platform 11 and then operates the operation button 41, the motor control unit 40 controls the motor 24 to move the slider 2 to the bottom dead center.

[0045] That is, when the output shaft 24a of the motor 24 rotates, the output rod 24d and the output member 25 move toward the front side. Since the upper end of the first link member 21 is connected to the output member 25, the first link member 21 swings so that its upper end moves toward the front side. Since the lower end of the second link member 22 is connected to the upper end of the first link member 21, the lower end of the second link member 22 is pushed toward the front side. At this time, since the upper end of the second link member 22 is connected to the end of the rear side of the third link member 23 and the third link member 23 swings only around the support shaft 15b, the lower end of the second link member 22 is pushed toward the front side, and the third link member 23 swings so that its front side moves downward. As a result, the slider 2 moves downward until it reaches the bottom dead center, so that the workpiece can be processed by the processing tool.

[0046] When the workpiece is processed, the third link member 23 elastically deforms upon receiving a reaction force from the workpiece. At this time, the frame 10 is a member that supports the slider 2 and also affects the processing accuracy, so it has high rigidity and is difficult to deform. On the other hand, the third link member 23 that transmits the processing force generated by the motor 24 to the slider 2 has lower rigidity than the frame 10, so that the amount of elastic deformation during processing is larger than that of the frame 10. Since the strain gauge 51 is attached to this third link member 23, it becomes easier to determine the linearity when converting the output of the strain gauge 51 into a load conversion value, and the output is also high. Therefore, the accuracy and reliability of the measurement result obtained by the conversion processing unit 52 are improved.

[0047] During processing, a bending force acts on the third link member 23. When the bending force acts on the third link member 23, the deformation around the relatively thin-walled insertion hole 23c becomes large. Therefore, by attaching the strain gauge 51 to the thin-walled portion of the third link member 23, the output of the strain gauge 51 can be increased.

[0048] The above-described embodiment is merely illustrative in all respects and should not be construed as limiting. Furthermore, all modifications and variations within the scope of the claims are within the scope of the present invention. [Industrial Applicability]

[0049] As described above, the press device according to the present disclosure can be used to perform various types of processing. [Explanation of symbols]

[0050] 1 Press equipment 2 Slider 10 Frames 15b Support shaft 20 Drive unit 23 Third link member 23c Insertion hole 24 Motor (machining force generating part) 50 Load measurement section 51 Strain Gauge 52 Conversion processing section

Claims

1. A press device that processes a workpiece with a processing tool by reciprocating a slider to which the processing tool is attached, a frame that supports the slider so as to be capable of reciprocating; A drive unit that drives the slider; A load measuring unit for measuring a load during processing by the processing tool, the drive unit includes a processing force generating unit that generates a processing force, a link member that transmits the processing force generated by the processing force generating unit to the slider, and a support shaft that supports the link member so as to be swingable relative to the frame, The load measuring unit includes a strain gauge attached to the link member and outputting an electrical signal corresponding to the deformation amount of the link member, and a conversion processing unit that converts the electrical signal output from the strain gauge into the load.

2. 2. The press device according to claim 1, The link member is formed with an insertion hole through which the support shaft is inserted, The strain gauge is attached to a portion of the link member that has been thinned by forming the insertion hole.

3. The press device according to claim 2, The processing force generated by the processing force generating unit is input to one end of the link member in the longitudinal direction, The slider is connected to the other end of the link member in the longitudinal direction. The insertion hole is formed in a longitudinal intermediate portion of the link member.

4. In the press device according to claim 3, The support shaft extends horizontally, The slider is supported on a front side of the frame as viewed from a user, the link member is disposed so as to extend from a front side to a rear side as viewed by a user of the frame, The insertion hole extends horizontally, One end of the link member in the longitudinal direction is disposed on the rear side as viewed from a user of the frame, the other end of the link member in the longitudinal direction is disposed on the front side as viewed from a user of the frame, A press apparatus, wherein the strain gauge is attached to an upper surface or a lower surface of the link member.

5. The press device according to claim 4, A press apparatus, wherein a plurality of the strain gauges are attached to an upper surface of the link member and a plurality of the strain gauges are attached to a lower surface of the link member.

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