JP3821052B2 - Material testing machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a material testing machine for measuring a mechanical strength of a material of a test piece by applying a tensile or compressive load to the test piece.
[0002]
[Prior art]
In this type of material testing machine, two screw rods are suspended from both sides of the machine base, the upper ends of both screw rods are connected by a yoke, and nuts are screwed into both screw rods. A cross head is installed between the screw rods via the nut, and the cross head is displaced in the screw rod axial direction by the rotation of the two screw rods or the nut, and between the yoke and the cross head or between the cross head and the machine base. A test piece is loaded and tested. FIG. 4 is a diagram showing a basic configuration of this conventional material testing machine, and two screw rods 3L and 3R are vertically suspended on both sides above the machine base 1. As shown in FIG. The machine base 1 is supported by a machine frame 2 surrounding the periphery, and an electric motor 10 and a rotational drive system for rotationally driving the screw rods 3L and 3R are installed below the machine base 1.
[0003]
That is, the electric motor 10 is fixed to the fixed portion of the machine base 1, but a V-groove pulley 11 is attached to the output shaft. On the other hand, the lower ends of both screw rods 3L and 3R penetrate the machine base 1 and protrude downward, and pulleys 12R and 12L having a diameter smaller than that of the pulley 11 and the same diameter are attached to the protruding ends. A V-belt 13 is hung between these pulleys 11 and 12R, 12L to constitute a rotational drive system. 9R and 9L are rolling bearings for rotatably supporting the screw rods 3L and 3R with respect to the machine base 1.
[0004]
The two screw rods 3L and 3R are provided with a crosshead 4 installed at intermediate positions via nuts 6L and 6R, and their upper ends are connected via a yoke 5. Both nuts 6L and 6R are screwed into screw rods 3L and 3R, respectively, but are integrally attached to the crosshead 4 via set screws 7L and 7R. Reference numeral 8 denotes a rolling bearing provided so that the screw rod 3R is rotatably held with respect to the yoke 5. A similar rolling bearing (not shown) is also provided above the screw rod 3L. .
[0005]
In the material testing machine shown in FIG. 4, the screw rods 3L and 3R are examples driven to rotate. However, the screw rods 3L and 3R are fixed and suspended from the machine base 1, and are held by the crosshead 4 and screwed. There is also a system in which nuts 6L and 6R that are screwed into the flanges 3L and 3R are rotationally driven. In this system, the nuts 6L and 6R are rotationally driven by an electric motor (not shown) or the like installed on the cross head 4, and the electric motor and the like are also moved up and down together with the cross head 4.
[0006]
In such a configuration, the test piece (not shown) is held between upper and lower chucks (not shown) connected to the yoke 5 and the crosshead 4 respectively. When the crosshead 4 is displaced downward by synchronously rotating the two screw rods 3L and 3R, a tensile load is applied to the test piece, and the tensile strength of the test piece is tested. In this case, the tensile load is measured by a load cell (not shown) interposed between the chuck and the yoke.
[0007]
On the other hand, a test piece (not shown) is installed between the crosshead 4 and the machine base 1 via a test piece holder (not shown) and the crosshead 4 is displaced downward and compressed into the test piece. A load is applied and a compression test is performed.
[0008]
[Problems to be solved by the invention]
In such a conventional material testing machine, the screw rods 3L and 3R are suspended from the machine base 1 and are rotatably provided. However, the screw rods 3L and 3R themselves move up and down with respect to the machine base 1. Not what you want. This also applies to the material testing machine in which the screw rods 3L and 3R are not driven to rotate. Therefore, the position of the yoke 5 is fixed with respect to the machine base 1. On the other hand, the machine base 1 is a base for a material testing machine, and is configured to have a certain height and size in view of the stability of the equipment. Since the screw rods 3L and 3R are vertically suspended above the machine base 1 having such a constant height, the position of the test is considerably upward. In particular, the tensile test performed by displacing the crosshead 4 downward is a test performed between the yoke 5 and the crosshead 4, and the test is performed because the height position of the yoke 5 is fixed and high, and the test is performed at a high position. Operation is not easy. In order to change the height position, the configuration of the testing machine becomes complicated, and the height cannot be easily adjusted.
The present invention is intended to provide a material testing machine that solves such problems.
[0009]
[Means for Solving the Problems]
In order to solve the above-described problem, the material testing machine provided by the present invention has two screw rods suspended from both sides of the machine base, and the upper ends of both screw rods are connected by a yoke and the two screws. A nut is screwed into each of the rods, and a cross head is installed between the screw rods via the nut. The cross head is displaced in the axial direction of the screw rod by the rotation of both the screw rods or the nut, and the yoke and the cross head are displaced. Alternatively, in a material testing machine that performs a test by loading a test piece between a crosshead and a machine base, two support nuts are rotatably installed on the machine base, and the screws are respectively attached to the both support nuts. A screw driving mechanism is used to support both screw rods, and a rotation drive mechanism is provided for rotating the both bearing nuts to move the screw rod up and down relative to the machine base. Therefore, the yoke and the cross head can be displaced up and down via the screw rod by the rotational drive of the support nut.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the material testing machine provided by the present invention will be described according to the embodiment shown in FIGS.
FIG. 1 is a diagram showing a basic configuration of a material testing machine according to the present invention, in which both screw rods 3L and 3R are supported on a machine base 1 via support nuts 25L and 25R. . That is, both screw rods 3L and 3R are screwed to a support nut 25L that is rotatably held via the rolling bearing 26 with respect to the machine base 1 as shown by the screw rod 3L. On the other hand, a V-belt 24 is wound around the support nuts 25L and 25R. The V-belt 24 is wound around a pulley 22 attached to the output shaft of the electric motor 21. When the electric motor 21 is driven to rotate, the support nuts 25L and 25R are rotated. With this rotation, the cross head 4 and the yoke 5 move up and down together with the screw rods 3L and 3R.
[0011]
Both bearing nuts 25L and 25R have the same size, and both screw rods 3L and 3R have the same diameter and the same pitch. Therefore, when both bearing nuts 25L and 25R are simultaneously driven to rotate by the rotation of the electric motor 21, both bearing nuts 25L and 25R are fixed and maintained with respect to the machine base 1 in the longitudinal direction of the screw rods 3L and 3R. Therefore, both screw rods 3L and 3R are synchronously displaced in the axial direction (vertical direction). For example, the screw rods 3L and 3R are displaced upward by the rightward rotation of the bearing nuts 25L and 25R, and are displaced downward by the leftward rotation.
When both screw rods 3L and 3R are displaced downward, the cross head 4 and the yoke 5 are lowered integrally, and a tensile test position is performed by holding a test piece (not shown) between the upper and lower chucks 14 and 15. Becomes a low position and facilitates the test operation.
[0012]
Incidentally, in the embodiment of FIG. 1, the cross head 4 and both screw rods 3L, 3R are coupled via nuts 19L, 19R, and in this respect, the same as FIG. 4, but in FIG. 19R is configured to be rotationally driven by the electric motor 16. The rotation of the electric motor 16 is transmitted to the nuts 19L and 19R through the pulley 17 and the V belt 18 to displace the crosshead 4 (for example, downward displacement). The nuts 19 </ b> L and 19 </ b> R are rotatably held with respect to the cross head 4 via the rolling bearing 20, but are fixed on both the upper and lower sides of the cross head 4 so as not to move up and down with respect to the cross head 4. It is held by plates 35L and 35R.
[0013]
Therefore, in the tensile test of a test piece (not shown) held between the upper and lower chucks 14 and 15, the electric motor 16 is driven to rotate. Then, when the nuts 19L and 19R are rotated to the right, for example, the crosshead 4 is displaced downward, and a tensile test is performed. The load on the test piece is measured by the load cell 27. In FIG. 1, parts denoted by the same reference numerals as those in FIG. 4 are the same as those in FIG. 4, and detailed description thereof is omitted.
[0014]
In such a tensile test or compression test, the support nuts 25L and 25R are fixed without being driven to rotate. The fixing of the support nuts 25L and 25R stops the driving of the electric motor 21. When the driving stop method of the electric motor 21 is not sufficient, a means for directly fixing the V belt 24 or the supporting nuts 25L and 25R is provided. In the test, it is necessary to adjust the vertical movement of the crosshead 4 so as to correspond to the length between the upper and lower chucks 14 and 15 depending on the length of a test piece (not shown). The nuts 19L and 19R are driven to rotate. The crosshead 4 is lowered according to the rotation direction, and the distance between the upper and lower chucks 14 and 15 can be varied. Fixing plates 36L and 36R are attached to both upper and lower sides of the machine base 1 so that the support nuts 25L and 25R do not move up and down.
[0015]
The material testing machine provided by the present invention is as described above, but is not limited to the above and the embodiment shown in FIG. For example, a modification as shown in FIG. 2 can be given.
FIG. 2 is a longitudinal sectional view showing a modified embodiment of the present invention in the same manner as in FIG. 1. In this modified example, the driving mechanism for performing the test by moving the crosshead 4 up and down is placed in the lower direction of the machine base 1. It is arranged. That is, 4M is a downward direction of both screw rods 3L and 3R, in other words, a lower crosshead constructed between the screw rods 3L and 3R inside the machine base 1, and this lower crosshead 4M is disposed at both ends thereof. Via the bearing 28, the lower azimuth | direction of both screw rods 3L and 3R is engaged rotatably. At the same time, an electric motor 29 is attached to the lower crosshead 4M.
[0016]
A pulley 30 is attached to the output shaft of the electric motor 29, and a V-belt 32 is stretched between the pulley 30 and pulleys 31L and 31R fixed to the lower ends of both screw rods 3L and 3R. That is, the electric motor 29, the pulleys 30, 31L, 31R, and the V belt 32 constitute a rotational drive mechanism for both screw rods 3L, 3R. 2 that are the same as those shown in FIGS. 1 and 4 are the same as those shown in FIGS. 1 and 4, and a detailed description thereof will be omitted.
[0017]
With the above configuration, the nuts 6L, 6R and the nuts 6L, 6L, 6R, and the nuts 6L, 6R and the nuts 6L, 6R that are screwed into the screw rods 3L, 3R by simultaneously rotating the pulleys 31L, 31R by the operation of the electric motor 29 are driven. The crosshead 4 fixed integrally with 6R moves up and down, and the test can be performed. That is, although not shown in FIG. 2, when the test piece is gripped between the chucks respectively attached to the crosshead 4 and the yoke 5 as in FIG. If it is displaced, a tensile test is performed.
[0018]
However, in this case, when both screw rods 3L and 3R are driven to rotate, the bearing nuts 25L and 25R are fixed due to the screwed relationship with the support nuts 25L and 25R, so that both screw rods 3L and 3R are moved up and down. become. When it is necessary to stop this vertical movement, the operation is performed so that both screw rods 3L and 3R do not move up and down by operating the electric motor 29 and simultaneously operating the electric motor 21 and driving the support nuts 25L and 25R in reverse. It is necessary to make it.
[0019]
Furthermore, in the present invention, the screw rods 3L and 3R may be ball screw rods which are screwed with nuts having balls such as steel balls, instead of screw rods formed by simple ordinary screws. FIG. 3 is a diagram showing an example of this ball screw system, in which the screwed relationship between the ball nut 33 and the ball screw rod 34 is partially shown in cross section. By applying this ball screw system to the configuration shown in the screw rod 3R and nut 19R shown in FIG. 1, there is very little screw-related friction and the rotational driving force of both screw rods 3L and 3R is small, and a so-called screw feed mechanism is provided. Provided is a material testing machine that can perform a test with good accuracy with little noise and a smooth test. Various configurations of the ball screw mechanism can be cited, and the configuration is not limited to the embodiment shown in FIG. Reference numeral 33H denotes a set screw hole for fixing the ball nut 33 to the cross head 4.
[0020]
Further, the embodiment shown in FIGS. 1 and 2 is an example in which the method of transmitting the rotation of the motors 16, 21 and 29 to the nuts 19L and 19R, the bearing nuts 25L and 25R, etc. is performed by the V-belt method. Instead of the V-belt system, a modification in which rotation is transmitted via a gear system is also applicable. In this case, it is necessary to attach gears to the output shafts of the electric motors 16, 21 and 29, and to attach gears to the nuts 19L and 19R, the supporting nuts 25L and 25R, etc. It is desirable to install in the stand 1.
The present invention includes these modifications.
[0021]
【The invention's effect】
Since the present invention has been described in detail above, both the screw rods, the crosshead, and the yoke can be displaced downward toward the machine base, and the entire testing machine can be reduced in size and size. Further, it is possible to provide a material testing machine that can easily set a test position by simply adjusting the height of the crosshead and the yoke without changing the chuck.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a material testing machine according to the present invention.
FIG. 2 is a view showing a modification of the material testing machine according to the present invention.
FIG. 3 is a diagram showing an example of a ball screw system as a screw feeding mechanism.
FIG. 4 is a diagram showing a configuration of a conventional material testing machine.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Machine base 3L, 3R ... Screw rod 4 ... Cross head 4M ... Lower cross head 5 ... Yoke 19L, 19R ... Nut 25L, 25R ... Support nut 14 ... Upper chuck 15 ... Lower chuck 16, 21, 29 ... Electric motor 33 ... Ball nut 34 ... Ball screw rod

Claims (1)

  Two screw rods are suspended from both sides of the machine base, the upper ends of both screw rods are connected by a yoke, and nuts are screwed into both screw rods. A cross head is installed on the test piece, the cross head is displaced in the screw shaft direction by the rotation of the two screw rods or nuts, and a test is performed by loading the test piece between the yoke and the cross head or between the cross head and the machine base. In the material testing machine, two support nuts are rotatably installed on the machine base, and the both screw nuts are supported by screwing the screw screws into the both support nuts. A material testing machine provided with a rotation drive mechanism for rotating the screw rod with respect to the machine base by rotating the screw rod.

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