JP4583767B2 - Mold and strain sensor unit used for the mold - Google Patents

Description

  The present invention relates to a mold for performing an appropriate molding process such as a bending process on a workpiece and a strain sensor unit used for the mold, and more specifically, deformation ( The present invention relates to a mold capable of detecting (strain) and a strain sensor unit thereof.

  Conventionally, for example, when a plate-like workpiece is bent by a press brake, a bending angle detector has been provided in the press brake in order to detect the bending angle of the workpiece every moment. As the bending angle detector, for example, a distance detection sensor is embedded in a plurality of locations of the die, and a distance dimension from each distance detection sensor to the workpiece is detected to calculate the bending angle of the workpiece. Yes.

It has also been proposed to calculate a workpiece bending angle by providing a sensor such as a strain gauge on the die to detect a horizontal component force and a vertical component force during bending of the workpiece (see Patent Document 1). .
JP-A-9-29341

  In the configuration disclosed in Patent Document 1, when a workpiece is bent, a component provided in the horizontal direction is detected by a sensor provided in the vicinity of the shoulder portion of the die, and the component force in the vertical direction is detected to fold the workpiece. Since the bending angle is calculated, the position of the sensor and the workpiece moves as the contact position between the workpiece and the die gradually moves downward from the upper portion of the die shoulder as the workpiece is bent. There is a problem in that it may be difficult to accurately detect a horizontal component force and a vertical component force because the relationship changes and the strain direction and magnitude near the shoulder change.

The present invention has been made in view of the above-described problems, and is a mold body provided with a V-shaped bending groove (5) for bending a plate-shaped workpiece (W) into a V-shape. (3), a groove formation in the plane perpendicular to the longitudinal direction of the upper surface (3U) of the mold body (3) and the bending groove (5), wherein the bending groove (5) is formed. A strain sensor unit (11) including a plurality of strain sensors (9) is embedded between a surface (5F) and the upper surface (3U), and one end of the strain sensor unit (11) is It is directed to the upper surface (3U) side, the other end portion is directed to the groove forming surface (5F), and the other end portion is obliquely arranged in a state lower than the one end portion. .

Moreover, the mold main body (3) provided with the V-shaped bending groove (5) for bending a plate-shaped workpiece (W) into a V-shape is provided. A strain sensor unit comprising a plurality of strain sensors (9) on both sides of the bending groove (5) in a vertical plane perpendicular to the longitudinal direction of the upper surface (3U) and the mold body (3). (11) is embedded symmetrically in a state parallel to the upper surface (3U), and a plurality of strain sensors (9) provided in each strain sensor unit (11) are provided in the bending groove (5). It arrange | positions at the same height in the position which adjoined, and the position away from the bending groove (5), It is characterized by the above- mentioned.

The strain sensor unit includes a plurality of strain sensors, and includes a mounting hole (19) having a non-circular cross-sectional shape in the axial center portion of the case (17) whose outer peripheral surface is circular. A sensor mounting surface (21A, 21B) is provided on the opposite side between the two joint surfaces of the base member (13) provided on the opposite side with a joint surface integrally joined to the inner surface of the hole (19), Strain sensors (9) are provided at equal intervals and symmetrically in a plurality of locations on the sensor mounting surface (21A, 21B) in the longitudinal direction of the base member (13) .

  Referring to FIG. 1, a mold 1 according to an embodiment of the present invention is a mold that performs a bending process as an example of a forming process of a plate-shaped workpiece W, and a mold body in the mold 1. 3, a V-shaped bending groove 5 for performing a V-shaped bending process on the workpiece W is provided. Then, distortion is detected in a strain generation region where distortion is likely to occur during bending (molding) of the workpiece W, that is, in a plurality of locations near the shoulder 7 of the bending groove 5 in the mold body 3. For this purpose, a strain sensor 9 is embedded.

  The plurality of strain sensors 9 are provided in a strain sensor unit 11. The strain sensor 9 is in a plane perpendicular to the longitudinal direction of the upper surface 3U of the mold body 3 and the bending groove 5 and between the groove forming surface 5F formed with the bending groove 5 and the upper surface 3U. It is arranged diagonally. That is, the mold of the strain sensor unit 11 is such that one end portion is directed to the upper surface 3U side, the other end portion is directed to the groove forming surface 5F, and the other end portion is lower than the one end portion. The main body 3 is embedded obliquely.

  As shown in FIG. 2, the strain sensor unit 11 includes the strain sensors 9 at regular intervals at a plurality of locations in the longitudinal direction of a base member 13 as a substrate made of an insulating member such as silicon. Each strain sensor 9 is assembled into a Wheatstone bridge by a plurality of resistors 15A, 15B, 15C, 15D in the X direction and the Y direction.

  The base member 13 can be directly fitted and fixed in a mounting hole formed in the measured portion. In this embodiment, the base member 13 is formed on a case 17 such as a ceramic case in order to protect the strain sensor 9. It is integrated by being fixedly fitted into the mounting hole 19 as the insertion hole. The outer peripheral surface of the case 17 is circular, and the mounting hole (insertion hole) 19 is formed in a non-circular shape such as a polygonal cross section. The base member 13 is integrally fitted and fixed so as not to rotate in the mounting hole 19.

  That is, the cross-sectional shape of the mounting hole 19 is formed in a rectangular shape in this embodiment. And the cross-sectional shape of the said base member 13 is a square shape, Comprising: The joint surface integrally joined to the inner surface of the said mounting hole 19 is provided in the mutually opposite side, The said strain sensor 9 is provided between the said joint surfaces. The sensor mounting surfaces 21A and 21B are provided on opposite sides. The sensors 9 are symmetrically disposed on the sensor mounting surfaces 21A and 21B.

  The plurality of sensors 9 provided on the one sensor mounting surface 21A are for detecting distortion in the X-axis direction of the mold body 3, and the plurality of sensors 9 provided on the other sensor mounting surface 21B are This is for detecting distortion in the Y-axis direction of the mold body 3. The gap between the sensor mounting surfaces 21A and 21B and the inner surface of the mounting hole 19 is filled with resin, and the base member 13 is integrally fixed to the case 17. The sensor 9 may have a structure appropriately provided on one sensor mounting surface. That is, it may be configured to detect only distortion in the X-axis direction or the Y-axis direction.

  When the strain sensor unit 11 having the above-described configuration is fitted and fixed in a mounting hole provided in the mold main body 3, the plurality of strain sensors 9 provided in the strain sensor unit 11 are provided on the mold main body 3. The strain sensors 9 are arranged in a plurality of locations within a plane perpendicular to the upper surface 3U and at a position close to the bending groove 5 and a position away from the bending groove 5.

  With the above configuration, the strain sensor 9 can detect the strain acting on the mold 3 when the workpiece W is bent.

Incidentally, the positions S ₁ (X ₁ , Y ₁ ), S ₂ (X ₂ , Y ₂ ), S ₃ (X ₃ , Y) of the plurality of strain sensors 9 arranged near the shoulder 7 in the mold body 3. ₃ ), S ₄ (X ₄ , Y ₄ ) is S _i (X _i , Y _i ), and the position of the force F acting on the shoulder 7 of the die body 3 by the bent work W is F (X, Y), the radius of the shoulder 7 is R, the angle between the upper surface of the mold body 3 and the workpiece W is θ, and the vertical line passing through the position F (X, Y) and the position F (X, If the angles θ ₁ to θ ₄ formed by the lines connecting the positions S _{1 to} S _{4 of} each strain sensor 9 from Y) are θ _i , the relational equation of force and strain distribution according to distance is given by the following equation.

σ = − (2F · Cos 2θ _i ) / (πr) (1)
Here, r is the distance away from the force and the element. The point of action of force F is on the arc of shoulder 7 and is given by:

(X−X ₀ ) ² + (Y−Y ₀ ) ² = R ₀ ² (2)
An angular relational equation between the contact point and each sensor-9 is given by the following equation.

θ ₁ = tan ⁻¹ [(X−X ₀ ) / (Y−Y ₀ )] (3)
θ _i = tan ⁻¹ [(X−X _i ) / (Y−Y _i )] (4)
The resulting strain values from the sensor (E _X, E _Y) relationship equation between the output voltage is given by the following equation.

_{V = C · (E X -E} Y) (5)
Here, V is an output voltage, and C is a gauge coefficient.

  If the above equations are solved simultaneously, information on the action point F (X, Y) of the force F can be obtained. However, when considering the influence of frictional force, two or more sensors are required. That is, if there are two or more sensors, the angle θ between the force F and the upper surface of the mold body 3 and the workpiece can be obtained, and the bending angle of the workpiece W can be obtained.

  As is clear from the above-described configuration, the strain sensor 9 is embedded at a plurality of positions near the shoulder portion 7 in the mold body 3 having the V-shaped bending groove 5, so that the shoulder portion at the time of machining the workpiece W is obtained. It is possible to detect not only the magnitude of the strain in the vicinity of 7 but also the strain distribution, and also to detect changes in the strain distribution with the progress of the bending process of the workpiece W. The relationship between the bending angle of the workpiece W and the change in the strain distribution can be grasped experimentally, for example, and the bending angle of the workpiece can be accurately detected by detecting the strain distribution. is there. In addition, since the distortion of the mold can be detected, when performing coining using the mold, it can be detected that the mold is in the state of breaking, and the mold is broken. It can be prevented beforehand.

  FIG. 4 shows a second embodiment. In this embodiment, the direction orthogonal to the upper surface 3U of the mold body 3 and the longitudinal direction of the mold body 3 (the direction perpendicular to the paper surface in FIG. 4). This shows a configuration in which the strain sensor unit 11 is symmetrically embedded in a vertical plane of FIG.

  In this configuration, the same effects as described above can be obtained.

  In the above description, the case where the strain sensor unit is embedded in the die for bending the workpiece has been described. However, the strain sensor unit can be embedded in various molds.

It is a section explanatory view of a metallic mold concerning a 1st embodiment of the present invention. It is a section explanatory view of a strain sensor unit. It is explanatory drawing which shows the relationship between several strain sensors, force, and the angle of a workpiece | work. It is sectional explanatory drawing of the metal mold | die which concerns on 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Mold 3 ... Mold main body 3U ... Upper surface 5 ... Bending groove 5F ... Groove forming surface 7 ... Shoulder part 9 ... Strain sensor 11 ... Strain sensor unit 13 ... Base member 17 ... Case 19 ... Mounting hole 21A, B ... Sensor Mounting surface

Claims (3)

A mold body (3) having a V-shaped bending groove (5) for bending a plate-shaped workpiece (W) into a V-shape is provided, and an upper surface of the mold body (3) ( 3U) and a plane perpendicular to the longitudinal direction of the bending groove (5) and between the groove forming surface (5F) on which the bending groove (5) is formed and the upper surface (3U). The strain sensor unit (11) including the strain sensor (9) is embedded, and one end portion of the strain sensor unit (11) faces the upper surface (3U) side, and the other end portion forms the groove. A mold characterized in that the mold is oriented obliquely so that the surface (5F) is oriented and the other end is lower than the one end . A mold body (3) having a V-shaped bending groove (5) for bending a plate-shaped workpiece (W) into a V-shape is provided, and an upper surface of the mold body (3) ( 3U) and a strain sensor unit (11) having a plurality of strain sensors (9) on both sides of the bending groove (5) in a vertical plane perpendicular to the longitudinal direction of the mold body (3). ) Are embedded symmetrically in parallel with the upper surface (3U), and the plurality of strain sensors (9) provided in each strain sensor unit (11) are close to the bending groove (5). The metal mold | die characterized by arrange | positioning at the same height in the position and the position away from the bending groove (5) . A strain sensor unit including a plurality of strain sensors, the mounting portion (19) having a non-circular cross-sectional shape in the axial center portion of the case (17) having a circular outer peripheral surface, 19) Sensor mounting surfaces (21A, 21B) are provided on the opposite sides between the joint surfaces of the base member (13) provided with joint surfaces integrally joined to the inner surface of 19), and the base member is provided. A strain sensor unit comprising strain sensors (9) at equal intervals and symmetrically at a plurality of locations on the sensor mounting surface (21A, 21B) in the longitudinal direction of (13) .

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