JP3289490B2 - Material testing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material testing machine for performing a bending test on a test piece.

[0002]

2. Description of the Related Art FIG.
As shown in FIG.
There is a double bending test in which d and Fu are alternately loaded. In this test, in order to hold the test piece TP against both the downward bending load Fd and the upward bending load Fu, the test piece TP is restrained by the restraint A from both sides in the load direction (vertical direction in the drawing).

[0003] Here, when the test piece TP is bent and deformed, FIG.
As shown in FIG. 2, the deflection angle θ and the displacement δ
Occurs. On the other hand, the restraint A sandwiches the test piece TP in the load direction, and is in a state in which it cannot move relative to the test piece TP in the longitudinal main axis direction (the longitudinal direction of the beam). For this reason, unless the restraint A is moved in accordance with the displacement δ, the load state of the test piece TP is not a simple bending state, and the test accuracy may be impaired. Therefore, conventionally, a bending portion B is disposed on the restraint A, and the bending portion B is elastically deformed with respect to a rigid body C such as a test machine main body as shown by a two-dot chain line in the figure to give a displacement δ.

[0004]

In the conventional structure described above, the flexure B is restricted by the span SP (for convenience, it is assumed to be the distance from the rigid body C to the neutral axis position of the test piece TP) and the bending rigidity. The magnitude of the displacement δ that can be given to the tool A is determined. However, the span SP cannot be increased without limitation due to restrictions on the height in the load direction or the like, and the bending rigidity of the flexure B cannot be excessively reduced due to the need to secure the strength of the restraint A. For this reason, it was difficult to give a large displacement δ to the restraint A. For example, a test piece TP with a span of about 5000 mm
When a bending load of about 0 t was applied, the displacement δ at both ends of the test piece reached 300 mm, and it was impossible to cope with such a bending test with a large load and large displacement.

An object of the present invention is to provide a material testing machine which can easily cope with a bending test with a large load and a large displacement.

[0006]

SUMMARY OF THE INVENTION According to the present invention, there is provided a material testing machine having a load mechanism for applying a bending load to a test piece, and a restraint tool contacting the test piece from both sides in the direction of the bending load. Is separated into a contact portion with the test piece and a support portion that supports the contact portion, the rotational displacement of the test piece in the bending angle direction between the support portion and the contact portion, and the support portion and the contact portion The above-mentioned object is attained by providing a floating mechanism which allows the test piece to slide in the longitudinal main axis direction between the test piece and the test piece.

[0007]

According to the present invention, the rotation of the contact portion with respect to the support portion of the restraint follows the change in the bending angle of the test piece, and the slip portion of the contact portion with respect to the support portion follows the displacement of the test piece in the longitudinal main axis direction. I do. The displacement of the test piece in the longitudinal main axis direction is given by the slip displacement in the restraint, so the displacement of the test piece in the longitudinal main axis direction of the test piece can be expanded regardless of the load direction size and bending rigidity of the restraint. .

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 7 and 8 schematically show a material testing machine according to the present embodiment, and 1 is a mounting table of the testing machine. The mounting table 1 is installed on the floor F or the like, and the tester main body 2 is mounted in the central recess 1a. The tester main body 2 includes a base 20
And a pair of columns 21 arranged on both sides of the base 20, an upper crosshead 22 connecting the upper ends of the columns 21, and a lower crosshead 23 arranged below the upper crosshead 22. The lower crosshead 23 is driven up and down along the column 21 by an actuator (not shown). The lower crosshead 23 is driven by various known methods such as directly moving the lower crosshead 23 up and down by reciprocating motion of a hydraulic cylinder, or converting the rotation of a motor into up and down movement of the lower crosshead 23 by a ball screw. A driving method may be used.

A pair of rails 3 are provided on the upper surfaces of the base 20 and the mounting table 1 so as to extend in the longitudinal direction of the lower crosshead 23.
Are provided perpendicular to the longitudinal direction of the. A pair of supports 4 are arranged on the rail 3, and the supports 4 support both ends of the beam-shaped test piece TP. A pair of four-point bending punches 5 and a center bending punch 6 are selectively disposed inside the support 4. The four-point bending punch 5 is connected to the lower crosshead 23 via a connecting beam 24 (omitted in FIG. 8), and is vertically moved to a position away from the center of the test piece TP by the vertical movement of the lower crosshead 23. Apply a load. Center bending punch 6 is lower crosshead 23
And a vertical bending load is applied to the center of the test piece TP by the vertical movement of the lower crosshead 23.
The load input to the test piece TP via the four-point bending punch 5 or the center bending punch 6 is detected by the load cell 25 attached to the lower crosshead 23.

The support 4 and the four-point bending punch 5 have a function of following the deflection angle of the test piece TP and the displacement in the longitudinal main axis direction due to bending deformation. Hereinafter, these configurations will be described. 1 and 2 show details of the support 4. FIG. 2 is a side view from the direction of arrow II in FIG. 1, and a portion on the right side of the vertical center line Cv is II-II in FIG.
The portion to the left of the line is mainly shown. As shown in these figures, the support 4 includes a support 40 mounted on the rail 3 and a chuck 41 supported by the support 40.
And a floating mechanism 42 interposed between the support 40 and the chuck 41. The support 40 is slidable along the rail 3 and a pair of vertical walls 400
Is provided. The chuck 41 includes a chuck body 410 surrounding the test piece TP, a pair of holding screws 411 screwed up and down on the chuck body 410, and a holding screw 41.
And a pair of shoe members 412 disposed at one end. The test piece TP is inserted between the shoe members 412, and is held between the shoe members 412 by screwing the holding screws 411. The contact portion between the holding screw 411 and the shoe member 412 is a spherical surface 411a, 412a.

The floating mechanism 42 includes a vertical wall 40 of the support 40.
Guide frame 420 fixed in square hole 401 provided in
And a slider 421 inserted into the guide frame 420
And a shaft member 422 having one end inserted into the slider 421 and the other end fixed to the chuck 41. A large number of needle rollers 423 are interposed in a vertical gap between the guide frame 420 and the slider 421, and the slider 421, the shaft member 422, and the chuck 41 slide integrally with the support 40 in the longitudinal direction of the test piece TP. It is possible. A radial bearing 424 is interposed between the slider 421 and the shaft member 422, and the shaft member 422 and the chuck 41 are attached to the support 40 by the shaft member 422.
Are rotatable integrally around the axis of. The center of rotation of the radial bearing 424 substantially coincides with the vertical center position of the test piece TP. 43 is a slider 42
Stopper bolts for restricting one slip displacement, and are attached to the pair of vertical walls 400 one by one in opposite directions. When the support 4 is not used, such as when the support 4 is transferred, the stopper bolt 43 is tightened and the slider 4
The slide displacement of the slider 421 is allowed by loosening the stopper bolt 43 when the support 4 is used.

FIGS. 3 and 4 show the details of the four-point bending punch 5. FIG. FIG. 4 is a side view from the direction of arrow IV in FIG. 3, and a portion on the right side of the vertical center line Cv mainly shows a portion on the left side of the IV-IV line in FIG. 3. As shown in these figures, the four-point bending punch 5 includes a support 50 suspended from the connection beam 24 (see FIG. 7) and a chuck 5 supported by the support 50.
1 and a floating mechanism 52 interposed between the support 50 and the chuck 51. An arbor 500 protrudes from the upper center of the support 50. When the screw portion 501 at the upper end of the arbor 500 is tightened with the nut 502, the support 5
0 is fixed to the fixed position of the connection beam 24. Nut 50
When the support 2 is loosened, the support 50 descends and the left and right rollers 50
3 comes into contact with the rail 240 of the connecting beam 24 and the rail 2
The position of the support 50 along the direction 40 can be adjusted. Since the moving mechanism using the roller 503 is provided in this manner, the load position of the test piece TP by the four-point bending punch 5 can be easily adjusted in the longitudinal direction of the test piece TP. Support 50
A pair of vertical walls 504 is provided below 0.

The chuck 51 has the same configuration as that of the above-described support 4, and includes a chuck body 510 surrounding the test piece TP, a holding screw 511 disposed above and below the chuck body 510, and a tip of the holding screw 511. A pair of shoe members 512 arranged to sandwich the test piece TP.
The same applies to the point that the contact portion between the holding screw 511 and the shoe portion 512 is a spherical surface 511a, 512a. The floating mechanism 52 also has the same configuration as that of the support 4, and has a guide frame 520 fixed in the square hole 505 of the support 5, a slider 521 inserted into the guide frame 520, and one end of the slider 521. A shaft member 522 inserted inside and the other end fixed to the chuck 51; a guide frame 520;
A large number of needle rollers 523 interposed between the slider 521 and the shaft member 522 to allow sliding displacement of the chuck 51 and a radial bearing interposed between the slider 521 and the shaft member 522 to allow the chuck 51 to rotate; 524. A stopper bolt 5 for preventing sliding displacement of the slider 521 during transportation or the like is provided on the vertical wall 504 of the support 50.
3 are provided.

A guide block 7 is provided on the rail 3 at a position facing the four-point bending punch 5 (see FIG. 7). The guide block 7 includes a pair of vertical walls 70 arranged so as to sandwich the four-point bending punch 5 from the neutral axis direction of the test piece TP (a direction parallel to the lower crosshead 23), and a plurality of vertical walls 70 attached to the vertical walls 70. Roller 71. Roller 71
Abuts against the vertical wall 504 of the support 50, whereby the displacement of the four-point bending punch 5 in the direction of the neutral axis of the test piece TP is regulated, and the support 50 is accurately guided in the vertical direction.
The guide block 7 and the support 50 are connected at an angle 72 when the material testing machine is transported. During the test, the angle 72 is removed.

FIG. 5 and FIG. 6 show details of the center bending punch 6. FIG. 6 is a side view from the direction of arrow VI in FIG. 5, and a portion on the right side of the vertical center line Cv mainly shows a portion on the left side of the line VI-VI in FIG. As shown in these figures, the center bending punch 6
It includes a support 60 connected to the lower crosshead 23 (see FIG. 7), and a chuck 61 supported by the support 60. The chuck 61 has the same configuration as that of the support 4 or the four-point bending punch 5 described above, and includes a chuck body 610 surrounding the test piece TP, a holding screw 611 disposed above and below the chuck body 610, and a holding screw 611. And a shoe member 612 which is arranged at the tip of the sample and sandwiches the test piece TP. Contact portions between the holding screw 611 and the shoe member 612 are spherical surfaces 611a and 612a. The chuck 61 includes a shaft member 62 and a radial bearing 63.
And is rotatable about the axis of the shaft member 62. The center bending punch 6 is guided in the vertical direction by the guide block 7 similarly to the four-point bending punch 5. The reason why the chuck 61 was not made to be capable of sliding displacement as in the case of the four-point bending punch 5 is that horizontal displacement due to bending deformation does not occur at the center of the test piece TP. However, the floating mechanism 52 described above may be applied to the center bending punch 6.

As shown in FIGS. 1 to 6, a guide mechanism 8 for moving the support 40 and the guide block 7 along the rail 3 is provided at the lower end of the support 4 and the guide block 7. FIG. 9 shows the details. Guide mechanism 8
Has a main body 81 fixed to the support 40 or the guide block 7 with bolts 80, a rotating shaft 82 horizontally mounted on the main body 81, and a wheel 83 fitted to the large-diameter portion 820 of the rotating shaft 82. . The wheel 83 is rotatable about the axis CL1 of the large diameter portion 820. Large diameter part 82
The zero axis CL1 is provided eccentrically with respect to the rotation axis CL0 of the rotation shaft 82.

When a work tool such as a wrench is applied to the hexagonal portion 821 at the shaft end of the rotating shaft 82 and the rotating shaft 82 is rotated by 90 ° from the position shown in the figure, the axis CL1 of the large-diameter portion 820 moves downward, and the wheels 83 move. Ground on rail 3. When the wheel 83 touches the ground, the stopper shaft 85 urged downward by the spring 84
And the stopper hole 822 of the rotating shaft 82
2 is blocked. Knob 8 at the upper end of stopper shaft 85
When the 6 is lifted, the engagement between them is released, and the rotating shaft 82 can be returned to the position shown in the figure. Note that a radial bearing can be used for the wheel 83, for example. According to the guide mechanism 8, the lifting and lowering work of the wheels 83 can be performed quickly. For example, in the mechanism for screwing the bolt BT to raise and lower the wheel W as shown in FIG. 10, the rotation angle of the bolt BT required to obtain the predetermined stroke ST is large, and quick operation is not possible.

In the material testing machine having the above configuration, the test piece T
To perform a 3-point double swing bending test of P, use a 4-point bending punch 5
Is removed from the tester, the test piece TP is inserted through the chucks 41 and 61 of the support 4 and the center bending punch 6. Subsequently, the center bending punch 6 is aligned with the center of the test piece TP, and the support 4 is moved along the rail 3 so that the support 4 is located at both ends of the test piece TP. After these positions are adjusted, the test pieces TP are vertically clamped by the chucks 41 and 61 by tightening the holding screws 411 and 611. Then, the lower crosshead 23 is raised and lowered,
A downward bending load and an upward bending load are alternately applied from the center bending punch 6 to the center of the test piece TP. At the mounting position of the support 4 with the change of the bending load, the test piece TP
The deflection angle and the displacement in the vertical main axis direction sequentially change, but the chuck 41 of the support 4 rotates and follows the support 40 with respect to the change in the deflection angle, and the displacement in the vertical main axis direction. The chuck 41 slides and follows the chuck 40 with respect to the support 40.

In order to perform the four-point bending swing test of the test piece TP, a four-point bending punch 5 is attached to the testing machine in place of the center bending punch 6, and then the support 4 and the chuck 41 of the four-point bending punch 5, The test piece TP is inserted into the test piece 51, and the four-point bending punch 5 and the support 4 are railed so that the four-point bending punch 5 is located at the load point of the test piece TP and the support 4 is positioned at both ends of the test piece TP. 3 in the longitudinal direction. The position of the guide block 7 is also adjusted according to the position adjustment of the four-point bending punch 5. After these position adjustments, the cap screws 411, 511
And the test piece TP is vertically sandwiched between the chucks 41 and 51. Then, the lower crosshead 23 is raised and lowered,
A downward bending load and an upward bending load are alternately applied from the four-point bending punch 5 to two points on the test piece TP. Also in this case, the chuck 41 rotates and horizontally displaces in accordance with the change in the bending angle at both ends of the test piece TP and the displacement in the longitudinal main axis direction. Also, the test piece T
The deflection angle of P and the amount of displacement in the direction of the vertical main axis are sequentially changed.
Follow and rotate and slide with respect to the support 50.

In the above embodiment, the tester main body 2 is used as a load mechanism, the support 4 and the four-point bending punch 5 are used as restraints, the chucks 41 and 51 are used as contact parts of the restraint, and the supports 40 and 40 are used as supports.
50 corresponds to the support portion of the restraint, and the floating mechanisms 42 and 52 correspond to the free mechanism of the restraint. In addition, the floating mechanism 42,
52 is not limited to the one using the needle rollers 423, 523 and the radial bearings 424, 524, and various motion guide elements may be used. For example, the needle roller 423 may be omitted from the support 4, and a material that reduces sliding resistance, such as a solid lubricant, may be interposed between the guide frame 420 and the slider 421. Although the swing test has been described above as an example, the present invention can be applied to various material testing machines that restrain the test piece TP from both sides in the load direction.

[0021]

As described above, according to the present invention,
The restraint is caused to follow the deflection angle and displacement of the test piece in the longitudinal main axis direction by the rotational displacement and slip displacement of the contact part with respect to the supporting part. Can be accurately followed. In particular, since the displacement of the test piece in the longitudinal main axis direction is allowed by the slip displacement in the restraint, it is possible to easily cope with a bending test with a large load and a large displacement.

[Brief description of the drawings]

FIG. 1 is a diagram showing a support of a material testing machine according to an embodiment of the present invention as viewed in cross section along line II of FIG. 7;

FIG. 2 is a side view of the support of FIG. 1 as viewed from the direction of arrow II in the figure.

FIG. 3 is a view showing a four-point bending punch of the material testing machine according to the embodiment of the present invention, as viewed in section along line III-III in FIG. 7;

FIG. 4 is a side view of the four-point bending punch of FIG. 3 from the direction of arrow IV in the figure.

FIG. 5 is a view showing a center bending punch of the material testing machine according to the embodiment of the present invention, as viewed in section along line VV in FIG. 7;

FIG. 6 is a side view of the center bending punch of FIG. 5 from the direction of arrow VI in the figure.

FIG. 7 is a diagram showing a schematic configuration of a material testing machine according to an embodiment of the present invention.

FIG. 8 shows a material testing machine according to an embodiment of the present invention by an arrow in FIG.
The figure which shows the state seen from VIII direction.

FIG. 9 is a diagram showing details of the guide mechanism shown in FIGS. 1 to 6;

FIG. 10 is a view showing a comparative example of the guide mechanism of FIG. 9;

FIG. 11 is a view for explaining a swing bending test.

FIG. 12 is a diagram for explaining a problem in a double bending test.

[Explanation of symbols]

 2 Tester main body 4 Support 5 4-point bending punch 6 Center bending punch 8 Guide mechanism 40, 50, 60 Support 41, 51, 61 Chuck 42, 52 Floating mechanism 423, 523 Needle roller 424, 524 Radial bearing TP Test piece

──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01N 3/20 JICST file (JOIS)

Claims (1)

(57) [Claims] 1. A material testing machine comprising: a load mechanism for applying a bending load to a test piece; and a restraint that abuts the test piece from both sides in a direction of the bending load, wherein the restraint is applied to the test piece. A contact portion and a support portion supporting the corresponding contact portion, rotation of the test piece in the bending angle direction between the support portion and the contact portion, and the support portion and the contact portion A material testing machine provided with a floating mechanism that allows a slip displacement in a longitudinal main axis direction with respect to bending of the test piece between the first and second test pieces.