JPH035889Y2 - - 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 too 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 device is disposed between the first load member and the support pin and/or between the second load member and the load pin, and the intermediate load device is aligned with the axis of the support pin and the load pin. It is possible to rotate around an axis perpendicular to both the direction of the load applied by the pins.

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 can be absorbed by rotating and tilting the intermediate load device at a small angle around a straight line, and the support pin and load pin can apply loads while completely aligned with both sides of the test piece. 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 highly accurate test results can be obtained despite the small amount of deformation required to break the test piece. It happens.

Moreover, the means for this purpose is simple, in that the intermediate load device is interposed between the first load member and the second load member and the support pin and the load pin in a state in which it can rotate around a straight line. The bending test jig can be manufactured at low cost.

Embodiment Hereinafter, an embodiment 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 on the lower outer circumferential surface of the cylindrical member 12, and a cylindrical member 12 with both ends open is fitted into the cylindrical member 12 with high precision, with the lower end surface of the cylindrical member 12 in contact with the flange 14. A groove 16 with a rectangular cross section is formed in the outer peripheral surface of the base 10 in parallel to its center line, and a portion of the groove 16 formed in the flange 14 protrudes downward from the lower end surface of the cylindrical member 12. By fitting the bent ear piece 18,
Relative rotation between the base 10 and the cylindrical member 12 is prevented.

As is clear from FIGS. 2 and 3, the upper surface 20 of the base 10 is formed with a protrusion 22 extending diametrically through the center thereof. Two support pin positioning grooves 24 with a rectangular cross section are formed as shown in FIG.
6 is formed. Support pin positioning groove 2
4 are spaced apart from each other at regular intervals in the longitudinal direction of the protrusion 22,
And, it is formed perpendicular to its longitudinal direction. The portion of the base 10 surrounding the support pin positioning groove 24 is hardened, and the bottom and both side surfaces of the support pin positioning groove 24 are finished with high precision by grinding.

A cylindrical support pin 28 is fitted into each of the support pin positioning grooves 24 so as to be substantially immovable in the width direction of the support pin positioning groove 24,
The upper portions of these protrusions project a certain amount upward from the upper end surface of the protrusion 22 . One U-shaped positioning member 30 is attached to a portion of the protrusion 22 located outside of each support pin positioning groove 24 so as to straddle the protrusion 22 at right angles to the longitudinal direction. Shallow notches 32 with a rectangular cross section are formed in the vertical direction on both sides of the projection 22, and the positioning member 30 is formed by fitting a pair of legs 34 hanging down from both ends into the notches 32. It is accurately positioned relative to the protrusion 22. As is clear from FIGS. 1 and 2, the positioning member 30 includes a pair of protrusions 36 facing each other on both end surfaces of the support pin 28.
This protrusion 36 prevents the support pin 28 from moving in the axial direction. As is clear from FIG. 2, the two positioning members 30 are further provided with specimen positioning grooves 38 having a rectangular cross section and extending in the vertical direction on mutually opposing surfaces of the central part, and in these positioning grooves 38, By engaging with both ends of the test piece 40, the width and length of the test piece 40 are positioned.

An upper loading tool 42 as a second loading member is disposed above the base 10. Upper loading device 42
has a large diameter portion 44 and a small diameter portion 46, and the small diameter portion 46 is slidably fitted into the upper opening of the cylindrical member 12. On the lower surface of the upper loading device 42,
As is clear from FIG. 1, a groove 48 is formed parallel to the support pin positioning groove 24. As is clear from FIG. 3, the bottom surface of this groove 48 is
It has a concave partial cylindrical surface 50 having its center on the center line, and an intermediate load tool 52 is disposed in close contact with this surface 50. This intermediate load tool 52
The upper surface is a convex partial cylindrical surface 54 corresponding to the concave partial cylindrical surface 50 described above. The intermediate load device 52 is further connected to the upper load device 42 by a connecting pin 56. The connecting pin 56 is provided so as to pass through the intermediate load device 52 parallel to the center line of the convex partial cylindrical surface 54, and both ends of the connecting pin 56 are connected to the groove 48.
It is loosely fitted into through-holes 58 formed in both side walls of. That is, the connecting pin 56 connects the intermediate load device 5
2 to the upper loading device 42, and the transmission of the load from the upper loading device 42 to the intermediate loading device 52 is performed by the convex partial cylindrical surface 54 of the concave partial cylindrical surface 50. It is meant to be.

A load pin positioning groove 60 is formed at the lower end of the intermediate load tool 52 at an intermediate position between the two support pin positioning grooves 24 and extending parallel to the support pin positioning grooves 24 . This load pin positioning groove 60 is a groove having a cross-sectional shape of a semicircle or more, and holds the load pin 62 with its lower end protruding downward from the lower surface of the intermediate load tool 52, and is perpendicular to its axis. This is for positioning in the direction.

The large diameter portion 44 of the upper loading device 42 is seated on the upper end surface of the cylindrical member 12 when the test piece 40 is not sandwiched between the support pin 28 and the load pin 62; In the pinched state, it is raised a short distance from the upper end surface of the cylindrical member 12. In addition, this upper loading tool 42
A groove 64 corresponding to the groove 16 formed in the base 10 is formed on the outer periphery of the cylindrical member 10, and a lug 66 projecting upward from the upper end surface of the cylindrical member 12 is fitted into this groove 64. This prevents relative rotation between the upper loading device 42 and the cylindrical member 12. Furthermore, a conical positioning recess 68 is formed in the center of the upper surface of the upper loader 42, and the lower part of the ball 70 is fitted into this recess 68.

A circular opening 72 is formed in two diametrically apart parts of the cylindrical member 12, and the test piece 4
0 can be attached and detached, and the attachment status can be confirmed.

When performing a bending test on the test piece 40 using the bending test jig configured as described above, the jig is attached to the test machine with the base 10 facing downward, and both ends of the test piece 40 are the test piece positioning groove 38
At the same time as attaching the support pin 2 to the support pin 2,
8 from below, and a load pin 62 is brought into contact with the upper surface of the intermediate portion.

In this state, the ball 70 is
If a downward load is applied to the upper loading device 42 via the test piece 40, a bending load will be applied to the test piece 40. The relationship between the magnitude of the load and the amount of deformation of the test piece 40 in this case is displayed and recorded by the measuring device of the testing machine until the test piece 40 breaks.

Since the test piece 40 is made of a brittle material, it breaks instantly when the bending load reaches a certain value. As a result, the load pin 62, intermediate load device 52, upper load device 42, and ball 70 fall, but the upper load device 42 is slightly raised from the upper end surface of the cylindrical member 12 as described above. Therefore, if it falls a short distance, its large diameter portion 44 will sit on the upper end surface of the cylindrical member 12, and it will not fall any further. Further, since the intermediate load device 52 is connected to the upper load device 42 by a connecting pin 56, and the load pin 26 is also held by the intermediate load device 52, these devices also fall by the same distance as the upper load device 42. only. Therefore, after falling for a relatively long distance, they are prevented from colliding with other components or the broken test piece 40 and damaging them or themselves.

In the bending test jig of this example, as is clear from the above description, the support pin 28 and the test piece 40 are formed in the support pin positioning groove 24 and the positioning member 30 formed in the base 10, respectively. Since the test piece 40 is positioned accurately by being fitted into the test piece positioning groove 38, the test piece 40 can be easily set and a load can be applied to an accurate position of the test piece 40. Moreover, since the two support pins 28 are supported by the bottom surfaces of the support pin positioning grooves 24 that have been finished with high precision by grinding, the parallelism of the portion of the support pins 28 that supports the test piece 40 is high, while load pin 6
2 is an intermediate load device 5 that can be tilted in the width direction of the test piece 40;
2, even if the parallelism between the top and bottom surfaces of the specimen 40 or the parallelism between the upper load section 42 and the base 10 is somewhat poor, these parallelisms will not be affected. The error is due to the intermediate load device 52
This is absorbed by the inclination of the test piece 40, so that no unbalanced load is applied to the test piece 40. Further, the load to the load pin 62 is transmitted by the intermediate load device 52 and the upper load device 42 which are in contact with each other directly above the load pin 62, while the load to the support pin 28 is transmitted by the base 10. Since the bending test is performed directly by the bending tester, a highly rigid bending test jig can be obtained. Furthermore, since the support pin 28 and load pin 62, which contact the test piece 40 and are likely to wear out, are simply fitted into the positioning grooves 24 and 60, 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.

All of the components of the bending test jig in the above embodiment are made of metal, and the parts that come in contact with each other are hardened and ground. If necessary, some or all of the components of the jig itself may be replaced with SiC, A
It is recommended to improve heat resistance and corrosion resistance by manufacturing with ceramic materials such as ₂ O ₃ , Si ₃ N ₄ , etc.

Further, in the embodiment, the intermediate load tool 52
is the load pin 62 and the upper load device 42 acting on it.
However, instead of or in addition to this, it is also possible to interpose an intermediate load device between the base 10 and the support pin 28. In this way, the two support pin positioning grooves 24
It is no longer necessary to finish the bottom surface of the support pin 28 with high relative positional accuracy, and even if the support pin 28 itself has a minute taper due to manufacturing error, this will not affect the test results.

Further, in the embodiment, the upper loading device 42
The transmission of the load from to the intermediate load device 52 was carried out by the concave partial cylindrical surface 50 and the convex partial cylindrical surface 54, but the lower surface of the upper load device 42 and the upper surface of the intermediate load device 52 It is also possible to transmit the load via the connecting pin 56 by forming a gap therebetween and increasing the diameter of the connecting pin 56.

Furthermore, it is also possible to directly form not only the support pin positioning groove but also the test piece positioning groove on the base 10.

In addition, various modifications and variations may be made to the present invention based on the knowledge of those skilled in the art, although no specific examples will be given.
Of course, it can be implemented in an improved manner.

[Brief explanation of the drawing]

FIG. 1 is a front view showing the left half of a bending test jig according to an embodiment of the present invention in cross section. FIG. 2 is a plan view showing the left half of the bending test jig in cross section. FIG. 3 is a side sectional view showing only half of the bending test jig. {10... Base, 12... Cylindrical member} First load member, 24... Support pin positioning groove, 28... Support pin, 30... Positioning member, 38... Test piece positioning groove, 40... Test Piece, 42... Upper load device, 50... Concave partial cylindrical surface, 52... Intermediate load device, 54... Convex partial cylindrical surface, 56... Connecting pin, 60... Load pin positioning groove, 62... ...Load pin.

Claims (1)

[Claims for Utility Model Registration] (1) Both ends of a longitudinal test piece are parallel to each other.
The specimen 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 pin. In a jig that performs a bending test by applying a force in a direction in which one load member and a second load member approach each other, An intermediate load device is disposed between them, and the intermediate load device is rotatable around an axis perpendicular to both the axes of the support pin and load pin and the direction of the load applied by those pins. Bending test jig. (2) The intermediate load device has a convex partial cylindrical surface centered on the straight line, and those of the first and second load members that act on the intermediate load device correspond to the convex partial cylindrical surface. The bending test jig according to claim 1, which is provided with a concave partial cylindrical surface, and which transmits the load while allowing rotation of the intermediate load device by sliding the partial cylindrical surfaces. .