JPH0325170Y2 - - Google Patents

Description

[Detailed description of the invention] Technical field The invention relates to a jig for performing a bending test by supporting both ends of a longitudinal specimen with support pins and applying a load to the middle part with a single load pin. .

BACKGROUND TECHNOLOGY The three-point bending test jig as described above is widely used, but when it is used to test brittle materials such as ceramics and cemented carbide, the amount of deformation required until the specimen breaks is Since the errors are small, errors in parallelism and dimensions of jigs and test pieces have a large impact on test results. Therefore, efforts have been made to reduce test errors by improving the precision of the dimensions, parallelism, etc. of jigs and test pieces.

Problems that the invention aims to solve However, there is a limit to improving the accuracy of jigs and test pieces as described above, and if the clearance of the moving parts is made too small, smooth loading may not be possible or the There is a problem that the durability of the tool may be reduced.

Means for Solving the Problems In order to solve the above problems, the present invention uses a three-point bending test jig as described above, and more specifically, bends both ends of a longitudinal test piece parallel to each other. The test piece is supported by the outer peripheral surfaces of two support pins, and the outer peripheral surface of one 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 forces in directions approaching each other by a support device and a load device, respectively, two support pins and one load pin are attached to the support device substantially in their diameter direction. three pin positioning grooves that are immovably accommodated in the test piece, and a test piece positioning groove that is perpendicular to the pin positioning grooves and that positions and accommodates the test piece substantially immovably in the width direction of the test piece. At the same time, the intermediate pin and the intermediate member are positioned between the support pin and the support tool and/or the load pin and the load tool using a test piece positioning groove, and
The intermediate member is placed on the side of the support pin or load pin, and the load applied to the intermediate pin from the support or load device is applied to the intermediate pin with the surface of the intermediate member that contacts at least the support pin or the load pin and the intermediate pin being a flat surface. The signal is transmitted to the support pin or load pin.

Function In the three-point bending test jig configured as described above, load is transmitted from the support or load device to the support pin or load pin via the intermediate pin arranged at right angles thereto. Therefore, when a load is applied by the loading device of the testing machine, the load is transmitted to the test piece while the support pin or load pin is allowed to tilt in the longitudinal direction.

Effects of the invention Therefore, according to the three-point bending test jig of the present invention, even if the parallelism between the upper and lower surfaces of the test piece or the parallelism between the load surfaces of the support and the loading device is insufficient, As mentioned above, these deviations in parallelism are absorbed by tilting the support pin or load pin in the longitudinal direction, and the support pin and load pin apply loads completely along 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 allows highly accurate test results to be obtained even though the amount of deformation required to break the test piece is small. Become.

Moreover, the means for this purpose is simple, in that the intermediate member and the intermediate pin are positioned and interposed between the support device or load device and the support pin or load pin using the test specimen positioning groove. The test jig can be manufactured at low cost.

In addition, in the present invention, since the intermediate pin and the support pin or load pin are each in line contact with the intermediate member, the contact surface pressure is reduced as in the case where the intermediate pin and the support pin or load pin are in direct point contact. is not excessive, and
Since the contact lines of the support pin or load pin and the intermediate pin with the intermediate member are perpendicular to each other, the degree of freedom of the support pin or load pin is similar to that when the support pin or load pin and the intermediate pin are in direct contact. is obtained.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail based on the drawings.

In FIG. 1, 10 is a support, support 1
0, as shown in FIGS. 1 and 2, consists of a cylindrical portion 12 and a small diameter protrusion 16 formed at the center of the cylindrical portion 12. A flange 18 is formed at the lower end of the columnar portion 12, and a circular recess 20 is formed at the bottom surface thereof. A cylindrical guide member 22 is fitted into this support 10 . The guide member 22 has an inner diameter of a large diameter, a medium diameter, and a small diameter in order from the bottom.
The lower end surface of the side wall surrounding flange 1
It is fitted into the support 10 with high accuracy while in contact with the support 8 . In addition, on the side wall surrounding the small diameter hole portion 26 of the guide member 22, there are a plurality of (four in this embodiment) through holes 28 at equal angular intervals whose center line is a straight line parallel to the center line of the guide member 22. It is formed.

Two support pin positioning grooves 30, one load pin positioning groove 32, and one test piece positioning groove 34 are formed in the upper part of the support 10, that is, in the upper part of the cylindrical part 12 and the protrusion 16. The upper part of the columnar part 12 and the protrusion 16 are each divided into a plurality of parts. The two support pin positioning grooves 30 are formed parallel to each other and horizontally in the columnar part 12, and the load pin positioning grooves 3
2 is formed parallel to the support pin positioning grooves 30, passing through the protrusion 16 at an intermediate position after the support pin positioning grooves 30. Further, the test piece positioning groove 34 passes through the center of the support 10 and is formed horizontally and at right angles to the support pin positioning groove 30 and the load pin positioning groove 32. Support pin positioning groove 30 and test piece positioning groove 3
4 is a groove with a rectangular cross-sectional shape, and the load pin positioning groove 32 is, as shown in FIGS. 1 and 3,
The groove has a curved bottom and a U-shaped cross section. The corner formed by the intersection of the load pin positioning groove 32 and the test piece positioning groove 34 of the protrusion 16 is chamfered, and at least these positioning grooves 30, 32 and 34 of the support 10 are chamfered. The formed portions are hardened, and the side wall surfaces of each positioning groove and the bottom surface of the support pin positioning groove 30 are finished with high precision by grinding.

A cylindrical support pin 36 and a cylindrical load pin 38 are fitted into the support pin positioning groove 30 and the load pin positioning groove 32, respectively, so as to be substantially immovable in the diametrical direction thereof. During use, the test piece 4 is placed on these two support pins 36.
0 is spanned over the test piece 40, and the load pin 38 is placed on the upper surface of the center part of the test piece 40. In this state, the test piece 40 is sandwiched between both side wall surfaces of the positioning groove 34, and is substantially stretched in the width direction. is immovably positioned. The side wall of the support pin positioning groove 30 has a height slightly smaller than the diameter of the support pin 36 so that when the test piece 40 is suspended over the support pin 36, both ends of the test piece 40 can be touched with fingers. has been done. Further, the guide member 2
The side wall of 2 has openings 42 at positions spaced apart in the diametrical direction.
are formed respectively, so that it is possible to easily attach and detach the test piece 40 and confirm the attached state.

The test piece positioning groove 34 further includes an intermediate member 44.
and intermediate pins 46 are fitted and positioned one by one. These intermediate member 44 and intermediate pin 46 are placed on the load pin 38 during use, and are fitted so that the intermediate member 44 is on the load pin 38 side. This intermediate member 44 is a member having a rectangular cross section, and its lower surface is in line contact with the load pin 38, and its upper surface is in line contact with the intermediate pin 46. The height of the protrusion 16 is such that when the intermediate member 44 and the intermediate pin 46 are fitted into the test piece positioning groove 34, the upper end of the intermediate pin 46 is above the protrusion 16.
The height is determined to be approximately the same as the top surface of the.

A loading tool 5 is installed in the small diameter hole 26 of the guide member 22.
0 is fitted with high precision and positioned with respect to the support 10, and the
Being guided through separation movements. The load tool 50 is composed of a large diameter portion 52 and a small diameter portion 54, and the small diameter portion 54 is slidably fitted into the small diameter hole 26, and the large diameter portion 52 is connected to the support pin 36 and the load pin. 3
When the test piece 40 is sandwiched between the guide member 8 and the guide member 22, the test piece 40 is raised a short distance from the upper end surface of the guide member 22. Further, the depth of the small diameter hole 26 is selected so that the small diameter part 54 is fitted with a length larger than its diameter, so that the loading tool 50 can be inserted smoothly without twisting. Can be slid.

The load tool 50 has a circular protrusion 56 at a position facing the intermediate pin 46 , and contacts the intermediate pin 46 at this protrusion 56 to apply a load to the load pin 38 via the intermediate pin 46 and the intermediate member 44 . Add. The small diameter portion 54, which is a fitting portion thereof, is fitted into the small diameter hole 26 formed in the guide member 22, thereby positioning the support tool 10 and the load tool 50 in the horizontal direction. In addition, the loading tool 5
A conical positioning recess 58 is formed in the center of the upper surface of the 0, into which a ball 60 is fitted, so that a load can be applied to the load tool 50 via this ball 60.

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 testing machine with the support 10 facing downward, and the test piece 40 is tested. It is fitted into the single positioning groove 34, and its both ends are supported by support pins 36 from below, and a load pin 38 is brought into contact with the upper surface of the intermediate part. Note that after fitting the test piece 40, the guide member 22 is moved from the state shown in FIGS. 1 and 3 by 90°.
The test piece 40 is rotated once so that the two openings 42 are located on both sides of the test piece 40 in the width direction.

In this state, the ball 60 is
If a downward load is applied to the load device 50 via
A bending load will be applied to the test piece 40. In this case, the relationship between the magnitude of the load and the amount of deformation of the test piece 40 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 38, the intermediate member 44, the intermediate pin 46, and the load tool 50 will fall, but the large diameter portion 52 of the load tool 50 will rise slightly from the upper surface of the guide member 22 as described above. Since the large diameter portion 52 falls a short distance and is seated on the upper surface of the guide member 22, it does not fall any further. In addition, the opening 4 of the guide member 22
2 are positioned on both sides of the test piece 40 in the width direction, so that the fragments hardly fly out and the fragments can be easily collected.

In the bending test jig of this embodiment, as is clear from the above description, the support pin 36, the load pin 38, and the test piece 40 are connected to the support pin positioning groove 30 formed in the integrated support 10, and the load Pin positioning groove 32 and test piece positioning groove 34
Since the test piece 40 is positioned accurately by being fitted into the test piece 40, it is easy to set the test piece 40.
And the load can be applied to a precise location on the test piece 40. Moreover, the two support pins 36 have support pin positioning grooves 3 that are precisely finished by grinding.
0, the part of the support pin 36 that supports the test piece 40 has a high degree of parallelism, while the load pin 38 receives the load by line contact via the intermediate member 44 and the intermediate pin 46. Because of this, when a load is applied to the intermediate pin 46, it can tilt in the longitudinal direction, and the parallelism between the upper and lower surfaces of the test piece 40 or the loading device 50 and the support device 10
Even if the parallelism is somewhat poor, the deviation in parallelism is absorbed by the inclination of the load pin 38, and no unbalanced load is applied to the test piece 40.

Also, in this way, the load pin 38 and the intermediate pin 46
are in line contact with the intermediate member 44, thereby preventing the contact surface pressure between them from becoming excessive, and the load pin 3 of the intermediate member 44
8 and the intermediate pin 46 are perpendicular to each other, the degree of freedom of the load pin 38 is close to that when the load pin 38 and the intermediate pin 46 are in direct point-like contact, and the unbalanced load on the test piece 40 is reduced. can be successfully avoided.

Furthermore, the load is transmitted to the load pin 38 by the ball 60, the load tool 50, the intermediate pin 46, and the intermediate member 44, which are connected in series directly above the load pin 38, while the load is transmitted to the support pin 36. Since the bending test is performed directly by the support 10, a highly rigid bending test jig can be obtained.

Furthermore, in this embodiment, since the through hole 28 and the opening 42 are formed in the guide member 22,
When testing the test piece 40 in a special atmosphere other than the air, or even in the air at high temperatures, the difference in atmosphere or temperature inside and outside the jig can be reduced, and accurate test results can be obtained. be able to.

Furthermore, in the jig of this embodiment, the support 10
A recess 20 is formed on the bottom surface of the jig, which reduces the weight of the jig and allows it to be used as an engaging part with a transport device when transporting the jig.

Further, the support pin 36 and the load pin 38, which contact the test piece 40 and easily wear out, are simply removed from the positioning groove 38.
0 and 32, if these are worn out, they can be easily replaced with new ones, and the accuracy of the entire bending test jig can be easily restored.

It should be noted that all of the bending test jigs in the above embodiments are made of metal materials, and the parts that come in contact with each other are hardened and ground. If it is necessary to conduct a test in the field, it is recommended that the components of the jig itself be made of ceramic materials such as SiC, Al ₂ O ₃ , Si ₃ N ₄ to improve heat resistance and corrosion resistance.

Further, in the above embodiment, the intermediate member 44 and the intermediate pin 46 were interposed between the load pin 38 and the load tool 50 that acts on it, but instead of or in addition to this, the support tool 10 and the support pin 36, an intermediate member 44 and an intermediate pin 46
It is also possible to intervene. In this way, even if the machining accuracy of the bottom surface of the support pin positioning groove 30 is slightly poor or if the support pin 36 itself has a taper due to manufacturing error, this will lessen the influence on the test results. . In addition, when an intermediate member and an intermediate pin are interposed between the support tool 10 and the support pin 36, the intermediate member and the intermediate pin have approximately half the length of the intermediate member 44 and the intermediate pin 46 in the above embodiment. Insert two of each with the support pin side facing up, and
Each set of intermediate members and intermediate pins may act independently on the two support pins 36.

Although not illustrated in detail, the present invention can be implemented in various modifications and improvements based on the knowledge of those skilled in the art.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view of a bending test jig which is an embodiment of the present invention. FIG. 2 is a plan view showing a supporting device included in the bending test jig shown in FIG. 1. FIG. 3 is a side sectional view of the bending test jig. 10... Support tool, 22... Guide member, 26...
Small diameter hole portion, 30...Support pin positioning groove, 32...
... Load pin positioning groove, 34 ... Test piece positioning groove, 36 ... Support pin, 38 ... Load pin, 40
... Test piece, 44 ... Intermediate member, 46 ... Intermediate pin, 50 ... Loading device, 60 ... Ball.

Claims (1)

[Claims for Utility Model Registration] Both ends of a longitudinal test piece are supported on the outer peripheral surfaces of two support pins parallel to each other, and one load parallel to the support pins is applied to the middle of the test piece. A jig for performing a bending test by bringing the outer circumferential surface of the pin into contact with the support pin from the opposite side, and applying a force in a direction in which the support pin and the load pin approach each other by a support tool and a load tool, respectively. three pin positioning grooves each accommodating two support pins and one load pin in a substantially immovable state in their diametrical direction;
forming a test piece positioning groove that is orthogonal to the pin positioning grooves and that positions and accommodates the test piece substantially immovably in the width direction thereof;
Positioning the intermediate pin and the intermediate member between the support pin and the support tool and/or the load pin and the load tool using a test specimen positioning groove, and arranging the intermediate member on the side of the support pin or the load pin,
The surface of the intermediate member that contacts at least the support pin or load pin and the intermediate pin is made flat so that the load applied to the intermediate pin from the support or load device is transmitted to the support pin or load pin by line contact. A 3-point bending test jig featuring: