JPH035890Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a jig for performing a bending test by supporting both ends of a longitudinal test piece with support pins and applying a load to the middle part with a load pin.

Prior Art Bending test jigs such as those described above are widely used, but when used to test brittle materials such as ceramics and cemented carbide, the amount of deformation required before the specimen breaks is small. Therefore, unbalanced loads due to poor parallelism of jigs and test pieces have a large impact on test results. Therefore, conventional efforts have been made to reduce test errors by improving the parallelism of jigs and test pieces as much as possible. However, there is a limit to the improvement in accuracy, and if the clearance of the movable part of the jig is made appropriately small, smooth loading may not be possible or the durability of the jig may be reduced.

Purpose of the invention Based on the above-mentioned circumstances, the present invention was developed to ensure that even if the parallelism of the test piece or jig is insufficient, an uneven load will not be applied to the test piece, allowing highly accurate testing. The purpose of this invention is to provide a bending test jig that provides good results and does not require the clearance of each movable part to be so small.

Structure of the invention The gist of the invention is to support both ends of a longitudinal test piece on the outer peripheral surface of two support pins parallel to each other, and to attach a load pin parallel to the support pins in the middle of the test piece. A jig that performs a bending test by abutting the outer circumferential surface of the support pin from the opposite side to the support pin, and applying force in a direction in which the support pin and the load pin approach each other by a first load member and a second load member, respectively, An intermediate load member is disposed between the first load member and the support pin and/or between the second load member and the load pin, and between the intermediate load member and the first and second load members. A ball is disposed between the intermediate load member and the intermediate load member, and the load is transmitted while allowing rotation of the intermediate load member about the spherical center of the ball.

Effects of the invention In the bending test jig configured as described above, the parallelism between the upper and lower surfaces of the test piece or the parallelism between the loading surfaces of the first load member and the second load member is insufficient. However, these deviations in parallelism are absorbed by the intermediate load member rotating and tilting by a minute angle around the spherical center of the ball, and the support pin and load pin are completely attached to both sides of the test piece and carry the load. This avoids unbalanced loads in which a particularly large load is applied to the portions of the test piece that are uneven in the width direction, and provides highly accurate test results even though the amount of deformation required to break the test piece is small. This will be obtained.

Moreover, the means for this purpose is simple, that is, interposing an intermediate load member and a ball between the first load member, the second load member, and the support pin or load pin, so the bending test jig according to the present invention can be manufactured at low cost.

Embodiments Hereinafter, some embodiments of the present invention will be described in detail based on the drawings.

In FIG. 1, 10 is a base, and a cylindrical member 1
2 constitutes the first load member. That is, although the base 10 is a member with a circular cross-sectional shape,
A flange 14 is provided at its lower end, into which a cylindrical member 12 with open ends is fitted with high precision, with its lower end surface abutting against the flange 14.

Two support pin positioning grooves 16, one load pin positioning groove 18, and one test piece positioning groove 20 are formed in the upper part of the base 10. The two support pin positioning grooves 16 are formed horizontally and parallel to each other with a certain distance apart in the horizontal direction, and the load pin positioning groove 18 is formed parallel to them at an intermediate position after the support pin positioning grooves 16. is formed. In addition, the test piece positioning groove 20
are formed horizontally and at right angles to the support pin positioning groove 16 and the load pin positioning groove 18. These positioning grooves 16, 18 and 20 are all grooves with a rectangular cross-section, and at least these positioning grooves 16, 18 and 2 of the base 10
The portion where 0 is formed is hardened, and the side wall surface of each positioning groove and the support pin positioning groove 16
The bottom surface is finished with high precision by grinding.

A cylindrical support pin 22 is fitted into the support pin positioning groove 16 so as to be substantially immovable in the width direction of the positioning groove 16, and its upper part extends a certain amount upward from the bottom surface of the test piece positioning groove 20. It is made to stand out. During use, the test piece 24 is suspended over these two support pins 22, and a load pin 26 is attached to the upper surface of the center part of the test piece 24.
The test piece 24 is placed in this state.
and the load pin 26 are respectively connected to the test piece positioning groove 2.
The depth of each positioning groove 16, 18, and 20 is determined so that the positioning groove 16, 18, and 20 are raised a certain distance from the bottom surface of the positioning groove 18 and the load pin positioning groove 18, and are sandwiched from both sides by the side wall surfaces of the positioning grooves 20 and 18. ing. Further, the upper part of the outer side wall of the support pin positioning groove 16 is cut off, and an opening 28 is formed in the side wall of the cylindrical member 12, so that the test piece 24 can be attached and detached and the attached state can be confirmed. There is.

A bottomed circular hole 30 is formed at the center of the upper end of the base 10, into which a disk-shaped intermediate load tool 32 is loosely fitted. The depth of the bottomed circular hole 30 is determined such that the upper part of the load pin 26 protrudes upward from the bottom surface of the bottomed circular hole 30 when the test piece 24 is attached. Further, at the center of the bottom of the bottomed circular hole 30, an escape hole 31 having a smaller diameter is formed with a depth that reaches the bottom of the test piece positioning groove 20.

The intermediate load device 32 has a load pin 2 on the bottom surface.
6. On the other hand, a conical positioning recess 34 is formed on the upper surface of the intermediate load tool 32, and a ball 36 is fitted into this recess 34, and the upper part of the ball 36 is made to protrude upward from the upper surface of the intermediate load tool 32. .

An upper loading tool 40 is fitted into the upper opening 38 of the cylindrical member 12 with high precision. Upper loading device 4
0 consists of a large diameter part and a small diameter part, the small diameter part is slidably fitted into the upper opening 38, and the large diameter part is used to hold the test piece between the support pin 22 and the load pin 26. In the sandwiched state, the cylindrical member 24 is raised a short distance from the upper end surface of the cylindrical member 12. This upper load device 40 has a similar positioning recess 41 at a position opposite to the positioning recess 34 of the intermediate load device 32, and engages the ball 36 here, and loads the load through the ball 36 and the intermediate load device 32. It functions as a second member that applies a load to the pin 26. The small diameter portion of the fitting portion is fitted into the upper opening 38 as a fitting hole of the first load member consisting of the base 10 and the cylindrical member 12, thereby connecting the first load member and the second load member. Horizontal positioning with respect to the load member is performed. Further, a conical positioning recess is formed in the center of the upper surface of the upper loader 40, into which a ball 42 is fitted.
A load is applied to the ball 42 through the ball 42.

When performing a bending test on the test piece 24 using the bending test jig configured as described above, the jig is attached to the testing machine with the base 10 facing downward, and the test piece 24 is tested. It is supported from below by the single positioning groove 22, and a load pin 26 is brought into contact with the upper surface of the intermediate portion.

In this state, the ball 42 is
If a downward load is applied to the upper loading device 40 via the test piece 24, a bending load will be applied to the test piece 24. In this case, the relationship between the magnitude of the load and the amount of deformation of the test piece 24 is displayed and recorded by the measuring device of the testing machine until the test piece 24 breaks.

Since the test piece 24 is made of a brittle material, it breaks instantly when the bending load reaches a certain value. As a result, the load pin 26, intermediate load device 32, ball 36, and upper load device 40 fall, but the upper load device 40 is slightly raised from the upper end surface of the cylindrical member 12 as described above. Since it is only a cylindrical member, it falls a short distance and its large diameter portion seats on the upper end surface of the cylindrical member 12, and does not fall any further. Further, the intermediate load tool 32 and the load pin 26 also come into contact with the bottom surfaces of the bottomed circular hole 30 and the load pin positioning groove 18, respectively, and the fall limit is defined. Therefore, after they have fallen a relatively long distance, other components and the specimen 2 after fracture
4 and damage them or itself is prevented. In addition, since the relief hole 31 is formed in the center of the test piece positioning groove 20, even if the test piece 24 is broken in a complicated manner and fragments are generated, the fragments will be removed from the side walls of the test piece positioning groove 20. and the test piece 24.

In the bending test jig of this embodiment, as is clear from the above description, the support pin 22, the load pin 26, and the test piece 24 are each integrated into the base 1.
Since the test piece 24 is positioned accurately by being fitted into the support pin positioning groove 16, the load pin positioning groove 18 and the test piece positioning groove 20 formed at 0, it is easy to set the test piece 24, and the test piece Loads can be applied at 24 precise locations. Moreover, the two support pins 22 have support pin positioning grooves 1 that are precisely finished by grinding.
6, the part of the support pin 22 that supports the test piece 24 has a high degree of parallelism, while the load pin 26 is supported by the ball 36 and the intermediate load device 32 so that a load can be applied thereto. Because it is oriented so that it can be tilted in any direction, even if the parallelism between the top and bottom surfaces of the test specimen 24 or the parallelism between the upper loading device 40 and the base 10 is somewhat poor,
These deviations in parallelism are absorbed by the inclination of the intermediate load tool 32, and no unbalanced load is applied to the test piece 24. Further, the load is transmitted to the load pin 26 by a ball 42, an upper load device 40, a ball 36, and an intermediate load device 32 that are connected in series directly above the load pin 26, while the support pin 22
Since the load is directly transmitted by the base 10, a highly rigid bending test jig can be obtained. Furthermore, since the support pin 22 and load pin 26, which contact the test piece 24 and are likely to wear out, are simply fitted into the positioning grooves 16 and 18, they can easily be replaced with new ones if they become worn. It can be replaced and the accuracy of the entire bending test jig can be easily restored.

FIG. 2 shows another embodiment of the present invention. In this embodiment, a low circular protrusion 44 is formed at the center of the bottom surface of the intermediate load device 32 in the above embodiment,
The intermediate load device 32 is brought into contact with the load pin 26 at this protrusion 44 . Since other parts are the same as those in the previous embodiment, corresponding components are given the same reference numerals and detailed explanations are omitted. However, in this embodiment, the contact between the intermediate load tool 32 and the load pin By reducing the area, the degree of freedom of the load pin 26 increases, and uneven loads on the test piece 24 can be better avoided.

Yet another embodiment of the invention is shown in FIG. This embodiment differs from the previous embodiment in that two load pins 26 are provided. The load pin positioning groove 18 for positioning the load pin 26 is
They are formed horizontally and parallel to the support pin positioning grooves 16 at positions spaced apart by the same distance from the center of the jig.

In this example, the intermediate load device 32 and ball 36 are attached to the test piece 2 as in the previous example.
4 and the jig itself, it also plays the role of evenly distributing the load applied from the upper load tool 40 to the two load pins 26,
A so-called four-point bending test can be performed with high accuracy.
Since other parts are the same as those in the embodiment shown in FIG. 1, corresponding components are given the same reference numerals and detailed explanations will be omitted.

The bending test jigs in each of the above embodiments are all made of metal, and the parts that come in contact with each other are hardened and ground. In some cases, it is recommended that the components of the jig itself be made of ceramic materials such as SiC, A ₂ O ₃ , Si ₃ N ₄ , etc. to improve heat resistance and corrosion resistance.

Further, in each of the above embodiments, the intermediate load device 3
2 and a ball 36 are interposed between the load pin 62 and the upper load device 40 that acts on it, but instead of or in addition to this, an intermediate load device and a ball are interposed between the base 10 and the support pin 22. It is also possible to intervene. In this way, there is no need to finish the bottom surface of the support pin positioning groove 16 with high precision, and even if the support pin 22 itself has a minute taper due to manufacturing error, this will not affect the test results. disappears.

The embodiments of the present invention have been specifically explained above, but
It goes without saying that the present invention can be implemented with various modifications and improvements based on the knowledge of those skilled in the art.

[Brief explanation of drawings]

FIG. 1 is a front sectional view of a bending test jig which is an embodiment of the present invention. FIG. 2 is a front sectional view showing only the main parts of another embodiment of the present invention. FIG. 3 is a front sectional view of yet another embodiment of the present invention. {10... Base, 12... Cylindrical member} First load member, 16... Support pin positioning groove, 18... Load pin positioning groove, 20... Test piece positioning groove,
22...Support pin, 24...Test piece, 26...Load pin, 32...Intermediate load tool, 36, 41...Positioning recess, 36...Ball, 38...Top opening (fitting hole), 40 ...Upper loading device (second loading member).

Claims (1)

[Claims for Utility Model Registration] (1) Both ends of a longitudinal test piece are parallel to each other.
The test piece is supported on the outer circumferential surface of a book support pin, and the outer circumferential surface of a load pin parallel to the support pins is brought into contact with the middle part of the test piece from the opposite side of the support pins. In a jig that performs a bending test by applying a force in a direction in which a load member and a second load member approach each other, an intermediate load member is disposed between the intermediate load member, and a ball is disposed between the intermediate load member and one of the first and second load members that acts on the intermediate load member; A bending test jig characterized in that load is transmitted while allowing rotation of an intermediate load member around the center. (2) A utility model registration request in which positioning recesses for positioning the ball are formed in both the intermediate load member and the member acting on the intermediate load member among the first and second load members so as to face each other. Bending test jig according to item 1. (3) The bending test jig according to claim 2, wherein the positioning recess is conical. (4) The bending test jig according to claim 2, wherein the positioning recess is a bottomed hole with a circular cross section slightly larger in diameter than the ball, and the bottom surface is flat.