Material Testing Machine

Abstract

To provide a material testing machine that prevents the tip of a gripper from falling vertically downward and does not apply resistance to deformation to a test specimen. [Solution] The material testing machine grips a specimen with three or more gripping devices arranged approximately horizontally and applies a test force to the specimen symmetrically about its center. Below the gripping devices, a support device is provided that allows the gripping devices to move approximately horizontally and restricts their movement approximately vertically downward.

Description

[Technical Field]

[0001] The present invention relates to a materials testing machine. [Background technology]

[0002] Patent Document 1 discloses a material testing machine that grips a specimen with a plurality of grippers arranged substantially horizontally and applies a test force to the specimen symmetrically about its center. Conventionally, in a material testing machine such as that disclosed in Patent Document 1, a guide rail is sometimes arranged below the gripping tool to prevent the gripping tool from tipping forward. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2016-515718 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the conventional guide rail configuration may cause a constraint on the gripping tool, which may cause resistance during the tensile test. An object of the present invention is to provide a materials testing machine that prevents the gripper from tipping forward and does not generate resistance during tensile testing. [Means for solving the problem]

[0005] One aspect of the present invention is a materials testing machine that grips a specimen with three or more gripping devices arranged approximately horizontally and applies a test force to the specimen in a centrally symmetrical manner, and that is equipped with a support device below the gripping devices that allows the gripping devices to move in an approximately horizontal direction and restricts movement of the gripping devices in an approximately vertically downward direction. [Effects of the Invention]

[0006] According to one aspect of the present invention, the gripper of a materials testing machine can be prevented from tipping forward, and no resistance occurs during a tensile test. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view showing a biaxial tensile testing machine. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II of FIG. [Figure 3] FIG. 2 is an enlarged perspective view showing the center of the biaxial tensile testing machine. [Figure 4] FIG. [Figure 5] FIG. [Figure 6] FIG. [Figure 7] FIG. [Figure 8] FIG. [Figure 9] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0009] [1. Embodiment] Fig. 1 is a perspective view showing a biaxial tensile tester 1. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. The biaxial tensile tester 1 is an example of a material testing machine.

[0010] Each figure shows the X-axis, Y-axis, and Z-axis directions of the biaxial tensile tester 1. The X-axis and Y-axis are axes that are perpendicular to each other in a horizontal plane, and the Z-axis is an axis that runs vertically and along the height direction of the biaxial tensile tester 1.

[0011] The biaxial tensile testing machine 1 is a material testing machine that performs a test by pulling an X-shaped or cross-shaped specimen T (see FIG. 4) in the X-axis direction and the Y-axis direction. The specimen T is a specimen for a biaxial tensile test. The biaxial tensile test is a test that complies with, for example, ISO standard 16842. As shown in FIG. 1, the biaxial tensile tester 1 includes a base 3 , a tension mechanism 5 supported by the base 3 , and a test stand 9 disposed in the center of the base 3 . The base 3 formed in an X-shape has a plurality of jack parts 11 at the bottom. The jack parts 11 allow the height of the base 3 to be adjusted.

[0012] The tensioning mechanisms 5 are an X-side tensioning mechanism 5X that pulls the specimen T with equal force in the +X and −X directions, and a Y-side tensioning mechanism 5Y that pulls the specimen T with equal force in the +Y and −Y directions, and are arranged orthogonally. The biaxial tensile testing machine 1 is equipped with an X-side control device that controls the X-side tensioning mechanism 5X and a Y-side control device that controls the Y-side tensioning mechanism 5Y, although not shown.

[0013] The tensioning mechanism 5 comprises a motor 15, a pulley belt 17, a pulley 19 and a shaft 23 at one end.

[0014] FIG. 2 is a cross-sectional view of a plane that passes through the shaft 23 extending in the X direction and extends in the Z-axis direction, viewed from the −Y direction toward the +Y direction.

[0015] 2, the pulley 19 has an orthogonal force transmission mechanism 21 at its bottom. The orthogonal force transmission mechanism 21 is engaged with the shaft 23. The orthogonal force transmission mechanism 21 is, for example, a worm wheel, and is engaged with a worm formed on the shaft 23. When the motor shaft portion 15A is driven by the motor 15 to rotate, the pulley 19 rotates via the pulley belt 17, and the orthogonal force transmission mechanism 21 rotates together with the pulley 19 about the Z axis, and accordingly the shaft 23 rotates about the Z axis.

[0016] 2, one end of the shaft 23 is supported by a shaft support 25 disposed adjacent to the motor 15. The shaft support 25 includes a pair of vertical plates 25A provided on the base 3 and a cylindrical portion 25B connected between the pair of vertical plates 25A, and the shaft 23 is rotatably supported by the cylindrical portion 25B. The other end of the shaft 23 is supported by a support plate 27 provided on the base 3.

[0017] The shaft 23 of the Y-side tension mechanism 5Y is positioned higher than the shaft 23 of the X-side tension mechanism 5X, and the two shafts 23 are positioned so as not to interfere with each other. The X-side tension mechanism 5X and the Y-side tension mechanism 5Y are positioned offset from each other so as not to interfere with each other, but because they have the same configuration, they will be collectively referred to as tension mechanisms 5 in the following description.

[0018] A pair of ball screw nuts 29 is provided on the shaft 23, and the shaft 23 and the pair of ball screw nuts 29 form a so-called ball screw mechanism. As the shaft 23 rotates, the ball screw nut 29 on the motor 15 side and the ball screw nut 29 on the opposite side move on the axis of the shaft 23 in directions that move away from or towards each other.

[0019] The ball screw nut 29 is connected to the lower part of a housing-like crosshead 31 provided on the base 3, and the ball screw nut 29 and the crosshead 31 move together. The crosshead 31 has a pair of blocks 33 on the sides of its lower part, and the blocks 33 are fitted into rails 35 mounted on the base 3. The blocks 33 and the rails 35 form a so-called guide rail mechanism. This allows the crosshead 31 to move on the base 3 in the axial direction of the shaft 23.

[0020] A rod 45 is inserted through the upper part of the crosshead 31. A connecting rod 45A is connected to the rod 45, and a gripping tool 41 is connected to the tip of the connecting rod 45A. The crosshead 31 is provided with a load cell 43 connected to a rod 45 on the opposite side to the test table 9. The load cell 43 is connected to a control device (not shown) and measures the test force, displacement, etc. of the gripper 41.

[0021] 1 and 2, the rod 45 is inserted into a rod support part 49 provided on the base 3 adjacent to the test stand 9 side of the crosshead 31. The rod support part 49 extends upward from the base 3 in a plate shape, and the rod 45 is inserted into a cylindrical opening at the top to support the load of the rod 45. The rod support part 49 also has an opening at the bottom so that the shaft 23 can be placed therein.

[0022] Next, the gripper 41 provided at the tip of the connecting rod 45A will be described. A connecting portion 53 is connected to the tip of the connecting rod 45A. The connecting portion 53 moves integrally with the crosshead 31 and the rod 45. A gripping tool 41 is connected to the connecting portion 53, and the gripping tool 41 grips and holds the specimen T.

[0023] Rotation of the motor 15 rotates the shaft 23, and the ball screw nut 29 and crosshead 31 move together, which moves the gripper 41 at the tip of the connecting rod 45A. The pulling mechanism 5 can pull the specimen T in two coaxial directions using a pair of grippers 41 arranged opposite to each other.

[0024] Next, the configuration around the test stand 9 will be described. Fig. 3 is an enlarged perspective view showing the center of the biaxial tensile testing machine 1. Fig. 4 is a plan view seen from above showing the test stand 9 and the gripping tool 41. Fig. 5 is a side view showing the gripping tool 41 and the support tool 69.

[0025] 3, the gripping tool 41 is divided into an upper part and an lower part, and includes an upper chuck 57 and a lower chuck 59. The upper chuck 57 and the lower chuck 59 are fastened together by a plurality of fasteners 55A, whereby the specimen T is clamped by the gripping tool 41.

[0026] FIG. 6 is a perspective view showing the test stand 9. As shown in FIG. The test stand 9 includes four support columns 61 extending upward from the base 3, and a base 63 supported on the upper ends of the support columns 61 and having a substantially square shape in top view.

[0027] A flat plate 65 is fixed via bolts 65A to each of the four sides of the base 63. Recesses 65B are formed in two locations on the plate 65, and a support member 69 is disposed in each of the recesses 65B. 5, the support tool 69 is positioned vertically below the gripping tool 41 and restricts the vertically downward movement of the gripping tool 41. The gripping tool 41 is provided at the tip of the connecting rod 45A and is heavy, so it is likely to fall vertically downward due to its own weight, but by being supported from below by the support tool 69, the vertically downward movement is restricted.

[0028] 7 is a perspective view of the support member 69, FIG. 8 is a plan view of the support member 69, and FIG. 9 is a side view of the support member 69. As shown in FIG. As shown in Figures 7, 8, and 9, the support device 69 comprises a pair of side plates 169, an annular movable body 170 supported by the pair of side plates 169, and a plurality of needles 171 rotatably supported on the surface of the movable body 170. Movable body 170 is of a caterpillar type. Needle 171 is disposed with its axis perpendicular to the rotation direction of movable body 170. Needle 171 is rotatable in the direction of arrow A in FIG. 9. Movable body 170 is rotatable in the direction of arrow B in FIG. 9. The needle 171 is an example of a rotating member.

[0029] Protrusions 173 are attached to the pair of side plates 169. The support member 69 is placed in the recess 65B of the plate 65 and fixed to the plate 65 by a fixing member 175. The fixing member 175 passes through the fixing hole 174 of the protrusions 173 and is fixed to the plate 65.

[0030] The support member 69 is a so-called linear roller bearing. The gripping tool 41 described above moves in the pulling direction while resting on the upper surface of the support tool 69. A plurality of needles 171 are exposed on the upper surface of the support tool 69, forming a substantially horizontal surface. As the movable body 170 of the support tool 69 rotates and the needles 171 also rotate, the gripping tool 41 does not encounter much resistance as it moves in the pulling direction. The needles 171 function as rollers that smooth movement in the pulling direction.

[0031] 4 and 5, the support members 69 are formed in a rectangular shape in plan view with a width in the pulling direction of the gripping members 41. As shown in Fig. 4, a pair of support members 69 are arranged on one side and the other side of the gripping members 41 in a direction perpendicular to the pulling direction. Fig. 5 shows gripping tool 41 in the +X direction. As shown in Fig. 5, the majority of the area of ​​support tool 69 mainly contacts the lower surface of connecting portion 53 of gripping tool 41, supporting gripping tool 41 from below. As gripping tool 41 moves, support tool 69 also contacts the rear end side of gripping tool 41 and the front end side of connecting rod 45A, for example.

[0032] As shown in FIG. 6, the plates 65 are attached to corresponding locations on the base 63, and the height of each of the four gripping tools 41 can be adjusted by adjusting the tightness of the bolts 65A. In addition, a space S extending in the vertical direction is created in the center of the base 63 on which the specimen T is placed, equal to the height of the support 69 provided on the plate 65, thereby preventing the specimen T from interfering with the base 63.

[0033] 4, the specimen T is pulled in four directions by a pair of first gripping tools 41X that apply a test force in the X direction and a pair of second gripping tools 41Y that apply a test force in the Y direction perpendicular to the X direction. That is, the specimen T is pulled in the X-axis direction and the Y-axis direction perpendicular to the X-axis direction.

[0034] In this embodiment, the support members 69 prevent the gripping tool 41 from moving vertically downward, but allow it to move easily in the pulling direction. Furthermore, the support members 69 do not restrict the gripping tool 41 from moving in a horizontal direction other than the pulling direction. The rod 45 to which the gripping tool 41 is connected is restricted from moving in a direction other than the pulling direction by the rod support members 49 and the like, but it can move slightly horizontally.

[0035] Therefore, for example, when the specimen T is deformed symmetrically in the +X direction and the -X direction and is distorted more in the +Y direction than in the -Y direction, the gripping tool 41 does not cancel out the load in the +Y direction. Also, when the specimen T is deformed symmetrically in the +Y direction and the -Y direction and is distorted more in the +X direction than in the -X direction, the gripping tool 41 does not cancel out the load in the +X direction.

[0036] In this embodiment, when a test specimen T is gripped with multiple grippers 41 and a test force is applied to the specimen T symmetrically about its center, the constraint factor of the grippers 41 as in the conventional method is eliminated, and the grippers 41 can be prevented from tipping forward while suppressing the generation of resistance when conducting a tensile test, thereby improving the reliability of the results of the tensile test on the specimen T.

[0037] 2. Other Embodiments The above-described embodiment merely exemplifies one aspect of the present invention, and any modifications and applications are possible without departing from the spirit of the present invention.

[0038] In the above-described embodiment, a biaxial tensile tester 1 that pulls the specimen T in two axial directions has been used as an example of a materials testing machine, but this is not limiting. In other embodiments, the materials testing machine may include three or more grippers 41 arranged substantially horizontally, with the axial directions of at least two of the grippers 41 being arranged so as not to be parallel. Even in this case, the specimen T deforms asymmetrically in a direction different from the one axial direction, but the plate 65, an example of a support, supports the grippers 41 so as to be movable in directions other than the axial direction, thereby achieving the same functions and effects as the above-described embodiment. For example, the material testing machine may be configured to have three grips 41 arranged at an angle of 120 degrees apart, or may be configured to have two parallel grips 41 and one grip 41 in another direction, for a total of three grips 41. The material testing machine may also be a multi-axis material testing machine equipped with three or more grips 41.

[0039] In the above-described embodiment, the pulling mechanism 5 constituting a ball screw is exemplified as a mechanism for pulling the gripper 41 in the axial direction, but the present invention is not limited to this. In other embodiments, the gripper 41 may be configured to be pulled by a pulling device such as an actuator.

[0040] In the above-described embodiment, the support 69 is a linear roller bearing, but the present invention is not limited to this as long as it does not become a factor in restricting the gripping tool 41 in the horizontal direction. In other embodiments, the support 69 may be a sliding member with reduced frictional resistance. The reduction in frictional resistance is achieved by the surface shape of the sliding member or by applying a lubricant. Furthermore, the support 69 may be configured to include a rotatable ball instead of the needle 171. A ball is an example of a rotating member. The support 69 is not limited to a bearing as long as the portion that abuts against the gripping tool 41 rotates in accordance with the movement of the gripping tool 41.

[0041] In the above-described embodiment, the plate 65 is not placed in the space S of the pedestal 63 below the specimen T gripped by the gripping tool 41. A predetermined member may be placed in the space S in the center of the pedestal 63 as long as it does not interfere with the specimen T being tested by the material testing machine.

[0042] [3. Aspects] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0043] (Section 1) One embodiment of a materials testing machine is a materials testing machine that grips a specimen with three or more gripping devices arranged approximately horizontally and applies a test force to the specimen in a centrally symmetrical manner, and is provided with a support device below the gripping devices that allows the gripping devices to move approximately horizontally and restricts movement of the gripping devices in an approximately vertical downward direction.

[0044] According to the materials testing machine described in paragraph 1, the support supports the gripper from below but does not restrict movement in other directions. This prevents the gripper of the materials testing machine from tipping forward and does not generate resistance during tensile testing.

[0045] (Section 2) In the material testing machine described in paragraph 1, the support device comprises a pair of side plates, a ring-shaped movable body supported by the side plates, and a plurality of rotating members supported rotatably on the surface of the movable body, and the rotation of the movable body and the rotation of the rotating members allows the gripping tool to move in an approximately horizontal direction.

[0046] According to the material testing machine described in paragraph 2, the support does not provide resistance to the axial movement that the grip normally performs. Therefore, the specimen can be pulled without any unnecessary resistance when the grip is pulled.

[0047] (Section 3) In the material testing machine described in paragraph 2, the rotating member is a needle, and the needle is arranged with its axis perpendicular to the rotation direction of the movable body.

[0048] According to the material testing machine described in paragraph 3, the needle rotates as the gripper moves, and does not create resistance to the axial movement that the gripper normally performs. Therefore, the specimen can be pulled without any unnecessary resistance when the gripper is pulled.

[0049] (Section 4) In the material testing machine described in any one of paragraphs 1 to 3, the grippers include a pair of first grippers that apply a test force in an X direction and a pair of second grippers that apply a test force in a Y direction that is perpendicular to the X direction.

[0050] According to the material testing machine described in paragraph 4, the specimen is pulled in a direction perpendicular to the other direction, so that the material testing machine can perform a biaxial tensile test using an X-shaped or cross-shaped specimen. [Explanation of symbols]

[0051] 1. Biaxial tensile testing machine (material testing machine) 3. Foundation 5 Pulling mechanism 9 Test Stand 11 Jack section 13 Control device 15 Motor 15A motor shaft 17 Pulley Belt 19 Pulley 21 Orthogonal force transmission mechanism 23 Shaft 25 Shaft support 25A vertical board 25B Cylindrical part 27 Support plate 29 Ball screw nut 31 Case 33 blocks 35 Rail 41 Grasping Tool 41X First gripper 41Y Second gripper 43 Load Cell 45 rod 53 Connecting part 55 Chuck 57 Upper chuck 59 Lower zipper 61 Pillar 63 Pedestal 65 plates 69 Support 169 Side Panel 170 Movable body 171 Needle (rotating member) 173 Convex Body 174 Fixed hole 175 Fixtures S space T specimen

Claims

1. A material testing machine that grips a specimen with three or more grippers arranged substantially horizontally and applies a test force symmetrically to the specimen, A support member is provided below the gripping tool to allow movement of the gripping tool in a substantially horizontal direction and restrict movement of the gripping tool in a substantially vertical downward direction. Material testing machine.

2. the support device includes a pair of side plates, an annular movable body supported by the side plates, and a plurality of rotating members rotatably supported on a surface of the movable body, The movable body rotates and the rotating member rotates, thereby allowing the gripper to move in a substantially horizontal direction.

2. The material testing machine according to claim 1.

3. The rotating member is a needle, and the needle is disposed with its axis perpendicular to the rotation direction of the movable body.

3. A material testing machine according to claim 2.

4. The grippers include a pair of first grippers that apply a test force in an X direction and a pair of second grippers that apply a test force in a Y direction perpendicular to the X direction.

4. A material testing machine according to claim 1.

Images